The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
Complete and utter speculation based on TV medical dramas and 'stuff I read somewhere' here - but AFAIK, a bang to the head can cause a bleed in the brain which, whilst not immediately fatal (or even apparent) can continue to leak blood into the surrounding spaces in the following hours. Eventually, if there's no more space for the blood to go, the intercranial pressure starts to build up to a dangerous level and the brain starts to gets squeezed. Without immediate medical attention, the base of the brain gets squeezed out, toothpaste-like through the hole in the base of the skull - at which point, the only effective treatment for the condition is a pine box. --Kurt Shaped Box (talk) 04:03, 19 March 2009 (UTC)[reply]
Since there's no publicly released information about the mechanism of injury or her medical condition, any response to this question is purely speculative as it applies to Ms. Richardson, and what follows is not intended to imply any one mechanism or cause of death, only what is possible.
That said, the are numerous ways a person could die from a closed head injury, including the slow bleeding scenario KSB described, which is usually a subdural haematoma. Other causes attributable to bleeding include extradural haemorrhage, subarachnoid haemorrhage, although this usually has a more precipitous onset, and intracerebral haemorrhage, to name a few. There are many conditions that increase the risk of some of these catastrophic bleeding problems, some of which are berry aneurysms and arteriovenous malformations. Contre coup type head injuries, and other blunt force, closed-head, traumatic injuries can lead to death through increasing cerebral oedema, ultimately causing the herniation of the lowest parts of the cerebellum throught the foramen magnum, which causes compression of the brain stem, where important things like consciousness, breathing and heart rhythm are controlled. This causes death. This is the process KSB described above, and is described by many doctors as "coning." It is caused by anything that increases intracranial (inside the skull) pressure sufficiently. More obscure causes in the setting of trauma exist, the first that comes to mind is acute high-pessure hydrocephalus that can be caused by a colloid cyst of the third ventricle blocking drainage of cerebrospinal fluid from the lateral ventricles. I could go on, but I won't! Mattopaedia Have a yarn06:07, 19 March 2009 (UTC)[reply]
It is reported that it was an epidural haematoma which sadly affected Natasha. This occurs when a bleed occurs in your head, between a layer called the dura and the skull. This causes an increase in intracranial pressure, resulting in a sort of compressive mechanism on the brain. Roughly 15-20% of people die from this condition, often because it's not as easy to diagnose as the other haemorrhages and haematomas listed above by Mattopaedia. —Cyclonenim (talk · contribs · email) 07:45, 19 March 2009 (UTC)[reply]
But she didn't hit anything, if the reports are correct! Thanks for the impressive list, too--though the skull is strong it's crazy how many ways the brain can go wrong. 69.203.78.244 (talk) 13:18, 19 March 2009 (UTC)[reply]
Brain injuries don't require an external impact. Sudden deceleration can do it, too, due to the brain's inertia causing it damage when it slams against the inside of the skull. StuRat (talk) 14:21, 19 March 2009 (UTC)[reply]
And, she did hit something - she hit the ground. That acounts for both impact and sudden deceleration. This story quotes a couple of ski patrollers who note that falls on flat sections of ski runs can be more dangerous than falls on slopes, as the skier just drops and stops rather than tumbling or sliding down the hill, which can absorb some of the impact. - EronTalk15:04, 19 March 2009 (UTC)[reply]
Indeed - I can tell you from experience that compacted snow is very hard. I've hit my head on the ground after a skiing fall, and it isn't pleasant (I've never required hospitalisation, fortunately). The worst such time was, indeed, on a flat section - right at the bottom of a dip, so I was going flat out, hit a bump, hit the ground and stopped immeadiately. I was completely dazed for several seconds. I don't find it at all hard to believe that someone less fortunate than me could get a fatal head injury from a similar fall. --Tango (talk) 19:16, 19 March 2009 (UTC)[reply]
A possible problem with spinning for Artificial Gravity
I have heard several way involving spinning a ring, or surface, or something to create centrifugal force for artificial gravity. I have always wondered: What would happen if I jumped up off the surface? Once I lost contact with the spinning surface, would I be weightless, or would my velocity bring me down again? Tiailds (talk) 04:18, 19 March 2009 (UTC)[reply]
If you start out spinning with the ring, you will have a lateral velocity. When you jump, that lateral velocity component does not change, so you will continue moving in that direction until you encountered the ring again. You will also have some amount of angular momentum, that will keep you rotating with the ring, so you will likely land in a roughly upright position. In extreme cases this would not be true and you could land at an awkward angle.
In contrast, if you started running in the direction opposite the ring rotation and managed to match that rotation, the centrifugal force would disappear and a jump would launch you into a weightless condition with the ring rotating around you. You could almost think of this as the equivalent of achieving orbital velocity in this inside-out environment. -- Tcncv (talk) 04:55, 19 March 2009 (UTC)[reply]
(EC with above)The idea is that you are on the inside of the spinning surface. Under those conditions, regardless of where you jump from, your straight-line motion (which your inertia will have once you are no longer in contact with a rotating frame of reference) will always bring you back into contact with the surface again. It's the centripetal force which is spinning the ring or whatever that provides you with that motion, not centrifugal force (a fictional force), which is really just the effect of losing contact with a rotating frame of reference and not a real force at all. Since your tendancy will be to move away from the center in both cases, being OUTSIDE the spinning ring will cause you to drift away, but being INSIDE the spinning ring will cause you to always drift into the ring. So you fall back to your "ground". --Jayron32.talk.contribs05:08, 19 March 2009 (UTC)[reply]
I spent a year and a half on Mars and all I got was this stupid t-shirt...
I have a few questions about a manned missions to Mars which Manned mission to Mars sadly does not answer:
First of all, what would be the length of such a mission? I hear people say that the trip there would take 3 months or so, but the entire trip would take much longer, wouldn't it? I mean, once you've taken three months getting there, haven't you pretty much missed your window of opportunity to get back? The article on exploration of Mars states that the launch window comes around every 780 days, so would that mean that the poor astronauts would have to spend something like a year and a half living on the surface of Mars? I'm having trouble even imagining how much food and fresh water you'd need to bring to stay alive that long (not to mention the psychological effects, I've read The Three Stigmata of Palmer Eldritch).
Second, what about communications with Earth? I mean, when Earth and Mars are sort-of near to each other, it wouldn't be much of a problem (you could live with a twenty minute latency, even if it's a pain in the ass), but assuming I'm right on part number one (a bold assumption), for most of the mission, Mars and Earth would be on opposite sides of the sun! Can you reliably communicate with someone when the sun is up? I'd imagine that the interference would be huge.
Third, what tangible benefits would a manned mission to Mars yield? Yes, I get the whole "triumph of the human spirit" thing and it would make a great television event, but if we just went up there to make measurements and bring back rocks for analysis, can't we just get robots to do that? I mean, yeah, the rovers didn't bring anything back, but I imagine it would be WAY easier to make a return trip with a robot compared to making one with a human being. No need to worry about some dude going ape-shit crazy and slaughtering the rest of the crew for one thing (presumably the robot would have a "become_self_aware = false" line in its code somewhere).
I'll comment on the second point only. The Sun would certainly block communications when directly in line between Earth and Mars, although that configuration might never occur during the mission (the two planets orbit in different planes, remember). I don't know about the more likely situation where it is almost directly in line, but experiments could be done to find out if it is a problem. And if it is, the thing to do is launch a communications relay satellite into a solar orbit that will keep it far enough away from the Earth-Sun line.
For single-mission use there would be a wide choice of orbits, but for long-term stability, the obvious thing is to use one of the Trojan positions, 60° ahead of behind of the Earth in its orbit. Incidentally, this solution was anticipated in science fiction as early as 1942, with George O. Smith's lighthearted Venus Equilateral stories. Smith was writing in the days of vacuum tube electronics and assumed the relay station would be manned -- as did Arthur C. Clarke when he invented the geosynchronous communications satellite in a nonfiction article about the same time. Smith's first story, "QRM—Interplanetary", is particularly worth looking for. --Anonymous, on Earth, 08:59 UTC, March 19, 2009.
(A) We're not talking about a solo flight. so the 790 days in point one wouldn't be spent in isolation. I would imagine an expedition consisting of a number of ships - minimum three - and dozens in the crew. (B) Magellan's Victoria took three years to circumnavigate the globe; FitzRoy's second Beagle expedition - the one with Darwin - took five. (C) Supplies need not all be carried along. Unmanned ships stuffed with MREs could be launched separately - starting before the manned component - and either inserted into orbit or dropped to the surface. (D) BTW, a second on the Venus Equalateral recommendation. B00P (talk) 09:40, 19 March 2009 (UTC)[reply]
While you're right we're not talking about a solo flight, the psychological effects of such a long trip in which a few people will be in constant close contact and very far from earth with limited contact are definitely something that has received a great deal of consideration (as with the physical effects) and is one thing that has been studied in numerous ways (e.g. [1] & [2]). Take a look at [3] and is also mentioned in Manned mission to Mars. I saw one suggestion a while back that choosing too many astronauts which are too perfect, as is the norm may actually be a mistake because they may not get along very well with each other over such a long time so there are definitely lots of different ideas. Basically of course, we will never know until it happens since there's no way you can simulate the conditions exactly. P.S. I've never heard a suggestion of multiple simultaenous crewed ships before. While I'm sure it has been proposed somewhere, I don't think it's high on the current list of ideas. Nil Einne (talk) 13:19, 19 March 2009 (UTC)[reply]
As having groups of people who can get along well together for years in confined spaces would be critical for the mission, they should make each group go through a test run for several years of isolation first. StuRat (talk) 19:00, 19 March 2009 (UTC)[reply]
That would be an extremely inefficient use of time. A 6 month spell on the ISS together might be good, although not all the people that would go on such a mission would be useful on the ISS (there aren't many rocks for geologists to study in LEO!). --Tango (talk) 19:04, 19 March 2009 (UTC)[reply]
As for supplies, such a mission would likely benefit from far more recycling than is currently done. Oxygen could be recycled from the air, and carbon dioxide removed (and maybe used to grow plants). Water could be recycled from the air (respiration and evaporation from skin and eyes) and from urine. Recycling food could also be done, say by using feces to grow food. Mushrooms, anyone ?
Another option is to produce some of the things we need directly on Mars. There is water ice at the poles, which could be used to supply water, and, after some electrolysis provided by solar power, oxygen. StuRat (talk) 11:55, 19 March 2009 (UTC)[reply]
An interesting thing that happens with my local NPRradio station periodically is that they'll say "at about X o'clock today, we'll lose transmission of this program due to the Sun passing behind the satellite that gives us our feed". And that's with your transmitter in front of the Sun. --Sean13:34, 19 March 2009 (UTC)[reply]
Manned mission to Mars still has that elephant of "Health threat from cosmic rays" in the closet. I haven't seen us make all that much progress in figuring out sufficient shielding. (Nanotube polymers are a very nice theory, but the spaceship would need more than a thimble full.) As to why, sooner or later our own planet is going to face a huge calamity. It would be nice for the survival of the species - if you are interested in that - to have a population stashed elsewhere by that time. If we intend to head in that direction we'd have to start some when somewhere. 76.97.245.5 (talk) 15:26, 19 March 2009 (UTC)[reply]
I may be misreading this, but in the original post, Belisarius says, "...Mars and Earth would be on opposite sides of the sun! Can you reliably communicate with someone when the sun is up?" The phrase "sun is up" usually refers to it being daytime and the earth does not orbit the sun during the course of a day, but over the course of a year. The sun being "up" would not necessarily be a problem; the sun being "between" would certainly be. Matt Deres (talk) 17:02, 19 March 2009 (UTC)[reply]
Yes, but you can only communicate when the Earth is above the horizon, which would be at the same time as the Sun was above the horizon. The OP's question does make sense. The Sun being up isn't actually a big problem, though, it's only a problem if it is very close to the Earth in the sky. --Tango (talk) 18:08, 19 March 2009 (UTC)[reply]
I'll take a shot at these:
1. First of all, what would be the length of such a mission? I hear people say that the trip there would take 3 months or so, but the entire trip would take much longer, wouldn't it? - yeah - it's partly the launch-window thing, partly that having spent 3 months getting there - and needing another 3 months to get back, it would be kinda silly to stay just a couple of days as we did on the moon. Plus, prolonged periods in zero G aren't good for you - and the guys will need time to recover some of their lost muscle and bone mass for the trip back home. This is also going to be a ruinously expensive trip - we won't be sending half a dozen manned missions there as we did to the moon.
I'm having trouble even imagining how much food and fresh water you'd need to bring to stay alive that long (not to mention the psychological effects - those are all very serious concerns. The plan currently is two-fold. One is to send an unmanned vehicle to mars to manufacture water and (by electrolysis) oxygen and some hydrogen fuel for the return trip - using sunlight for energy, subterranean ice as a water source...whatever. When it has enough supplies built up - we send out our manned mission with enough fuel for a one-way trip - and only enough water and oxygen for the ride out there. We'd need to recycle (we already do that on the ISS for example) - and we'd need to grow our own food en-route using hydroponics and such like. It's not easy - and that's why we didn't do this LONG ago! When we get there - we land a short distance from the robotic mission's landing site - fill up on fuel, water oxygen for the stay - refill again for the trip home. Psychological concerns have been somewhat addressed. Plenty of people have been cooped up in the ISS and in MIR for a year and managed to keep it together that long. Being able to leave the spacecraft and wander out across Mars should make that easier - not harder.
2. Second, what about communications with Earth? - No problem. We've been communicating with the 'Spirit' and 'Opportunity' rovers non-stop for something like five years now! We can still send messages to (and get data back from) the clunky old Voyager probes that have completely left the solar system. This is really not a problem.
3. Third, what tangible benefits would a manned mission to Mars yield? - I have a problem with this too. There is value for sure in having LOTS of humans living their lives on Mars - we need a 'backup planet' in case something terrible happens to ours. For that reason only - we need to make a start on being there - and the first step is to get a small crew out there.
No need to worry about some dude going ape-shit crazy and slaughtering the rest of the crew for one thing - again, it didn't happen with people cooped up in the TINY space of MIR over an entire year (although they certainly had their problems). I think once they get to Mars - they'll be too busy to worry.
(presumably the robot would have a "become_self_aware = false" line in its code somewhere). - :-) Indeed - Asimov's first law of robotics is a "must have" kind of thing...and no putting red LED's in it's fake eyesockets either...that's just not funny! Particularly avoid: "if ( become_self_aware == true ) eye_socket_LED_illumination_level = 1.0f ;"
It took me a while to work out what you were saying that (I didn't cheat and click the link!), but I laughed out loud when I got there - very good! --Tango (talk) 14:54, 20 March 2009 (UTC)[reply]
Strictly speaking, we haven't communicated with Spirit and Opportunity non-stop - there are short periods when they are out of contact due to the position of the Sun. It's only a couple of days a year, or so, though. The lack of real-time communication with anyone other than your crewmates might make life on Mars a little harder than life on MIR/ISS - the psychological issues certainly need to be dealt with, but I don't think any of them are deal-breakers. --Tango (talk) 14:54, 20 March 2009 (UTC)[reply]
To answer the OP's third question: Mars can be explored much faster with humans than with robots because robots are nowhere near as intelligent as a human. Consider this recent possible discovery of liquid water on Mars, for example. It's been months since the pictures were sent back, yet scientists still aren't sure whether what they're seeing is liquid water. If any human saw that substance, he could poke at it and figure out whether it's water within a few seconds.
Another example: Spirit and Opportunity, the two rovers exploring Mars, are constantly meeting obstacles, stopping, and asking Earth for directions. Just read this update archive. It took days for Spirit to get around a potato-sized rock. It's hard to imagine anything a human failing to navigate around anything smaller than a mountain.
So, why should robots not be made self-aware? I'd think conscious robots would be extremely helpful in exploring Mars, as they'd presumably allow the planet to be explored with on-the-spot decisions (as opposed to decisions made by Earth, which take a long time). --Bowlhover (talk) 00:57, 21 March 2009 (UTC)[reply]
"Mars can be explored much faster with humans than with robots because robots are nowhere near as intelligent as a human. " An opposing argument is that it is cheaper to send a robot, because we don't care if it never comes back. A "Hero Astronaut" must have a return capability, with multiple redundant everything. A robot just goes there and is abandoned when it quits working. If it crashes or falls in a hole, too bad, and we send another a bit later. It is far cheaper to send an analytical lab there than to send a Hero Astronaut to walk around for a bit and then bring rocks back. Plus, we avoid the Andromeda Strain scenario wherein pathogens wreak havoc back on Earth. Edison (talk) 02:15, 21 March 2009 (UTC)[reply]
Another way to look at is that we could probably send dozens of rovers, more quickly, and for less cost, than a human crew. Those rovers could stay functional on Mars for longer than a human, who would likely need to head home after a brief visit. StuRat (talk) 05:39, 24 March 2009 (UTC)[reply]
Research with Blood
What is the easiest way to overlay blood on to a FiCol or similiar medium before centrifugation? Currently you have to poor blood from one test tube to another prefilled with medium (ficol) 15-50 mL test tube. —Preceding unsigned comment added by 98.154.31.61 (talk) 07:36, 19 March 2009 (UTC)[reply]
I suggest that you start with a tube containing blood diluted 1:1 (to reduce loss of mononuclear cells at the interface) and underlaying with Ficoll. You need a very clean interface to get good separation. To achieve this, use a long pipette attached to a pipette-aide, load it with the desired amount of Ficoll for the blood volume and tube size you're using, insert through the blood to the bottom of the tube, then very slowly dispense the Ficoll, being careful to avoid ejecting a bubble of air! Spin with the brake off, of course. --Scray (talk) 11:07, 19 March 2009 (UTC)[reply]
Waterflow of the Amazon River
I am interested in knowing more about the force and speed of the waterflow/steady stream of the Amazon, i.e. close to the outlet but before the flow is divided by the "branches" of the delta. Perhaps this can be calculated from the daily amount of water going from the river into the sea, with the tide taken into account?
Does anyone have information about the speed of the flow out to sea? It would be an interesting addition to the page.
On the Amazon river page, the information box notes that the "Discharge - average" at the mouth is 219,000 m³/s; I'll let you do the conversion, but you should get a little over 1013 L/day (a truly mind-boggling amount). My impression is that this takes into account tides, etc. The Drainage area section notes that this can increase almost 40% to 300,000 m³/s during the wet season. What is it you wanted to add? The Talk page might be a good place to discuss additions. --Scray (talk) 11:24, 19 March 2009 (UTC)[reply]
Using Scray's numbers, roughly 1013 L/day, divide by 24, then by 60 and then 60 again to get per second which gives us approx. 1.16 x 10^9 L/sec. Seeing that one liter of water is approximately one kilogram, we can assume 1.16 x 10^9 kg if the mass of the water.
Speed of the Amazon is approximately 3 miles per hour, which is 1.34 m/s-1. Seeing as one liter of water weights approximately one kilogram, we can convert Scray's value of 1013 per day into 1.16 x 109 kg of water flowing per second. Using F=ma, 1.16 x 109 x 1.34 gives us 1.55 x 109 N of force. I feel that's unusally high, but I'm not a good physicist so I'll let others rip that working out to shreds. —Cyclonenim (talk · contribs · email) 16:58, 19 March 2009 (UTC)[reply]
A liter of water has a mass of exactly one kilogram, by definition, not approximately, though there are obviously additives that will change the actual measured mass/weight. Matt Deres (talk) 17:06, 19 March 2009 (UTC)[reply]
I was just wondering how much suspended sediment load there would be in a litre of Amazon river water, so I did a back of the envelope calculation taken from some annual figures of discharge and sediment load (6300 km3 per year & 1200 x 106 tonnes per year [4]), and came up with a mere 0.2 g of suspended sediment in each litre; enough to make it look a bit murky but not enough to seriously affect the approximation. Mikenorton (talk) 19:14, 19 March 2009 (UTC)[reply]
Just as an aside, the Amazon is recognised as the largest river in the world by volume, but is it true what I read that there is an underground "river" underneath the Nile that is six times bigger than the river on land? ~AH1(TCU)01:46, 20 March 2009 (UTC)[reply]
Beneath the Nile there is an enormous canyon created by the drop in base level associated with the Messinian salinity crisis. That is now filled with silt, I don't know if there is likely to be any significant groundwater flow through this great pile of sediment (2400 m thick beneath Cairo) that could be compared to the surface flow. There is interaction between the Nile and aquifers in its banks in the Cairo area, both discharge and recharge,[5] but I'm not sure you would call any of that an underground river. Mikenorton (talk) 11:44, 20 March 2009 (UTC)[reply]
Web search for "callus culture" provides plenty of information. If you have a specific question, please state it clearly and I'm sure people here will respond with similar care. --Scray (talk) 12:48, 19 March 2009 (UTC)[reply]
1) They don't. Their nostrils stay above the waterline in their normal floating position, so they can breathe normally.
2) When they do go underwater, just being a reptile allows them to hold their breath much longer, since reptiles are cold-blooded. Warming the body requires a great deal of energy, and "burning" that energy requires oxygen. Therefore, the oxygen requirements for cold-blooded animals are far lower. StuRat (talk) 11:39, 19 March 2009 (UTC)[reply]
Cold-hearted orb that rules the night....
I'm under the impression that the center of the Moon is far cooler than the center of the Earth. This brings up some Q's:
1) What are those two temps ?
2) Why the diff ? Does it have anything to do with the Moon being tidally locked to Earth, but the Earth not being tidally locked to the Moon ?
3) Is there a formula which can predict the temp at the center of a planet or moon, based on it's mass and distance from the Sun ? (I'd include density, but that may also be somewhat dependent on the temperature). StuRat (talk) 11:35, 19 March 2009 (UTC)[reply]
Partial answer to part 1: Various sources for the earth's core temperature are listed here with 7000 c. being most prevalent, 10,000 c. here, and 9,000 here, so as you can see there's little agreement, which is unsurprising given that we have no direct measurements and all answers are currently based on extrapolation. By the way, are you a Moody Blues fan? (or were they quoting someone else when they used that line?)—70.19.64.161 (talk) 12:17, 19 March 2009 (UTC)[reply]
The redirect made me think my spelling was correct. I wish they had a different color for links which point to redirects, to avoid this problem. The KKK members fancy themselves to be feudal knights, and often wear white satin robes (and many would consider them to be "white satans", too). The Birth of a Nation poster demonstrates both aspects. StuRat (talk) 14:50, 19 March 2009 (UTC)[reply]
For (2), that's likely some part of it, but our structure of the Earth article suggests that the prime source of heat is left over from planetary contraction. Given that the Earth is on the order of 80 times more massive than the Moon, I expect that explains the discrepancy nicely. For a partial answer to (1), inner core puts it at approximately the temp of the sun's surface, 5800K. — Lomn12:21, 19 March 2009 (UTC)[reply]
This source [6] gives a temperature for the centre of the moon as 830°C (1003°K). It also suggests that this temperature means that the concentration of radiogenic isotopes is greater than within the earth. If it wasn't for this heat source both bodies would be a whole lot colder (or need to be much younger). Mikenorton (talk) 12:58, 19 March 2009 (UTC)[reply]
I had no idea it was that hot. That means there's some point under the surface which is always a good temp for people, doesn't it ? It would also mean that "lunarthermal" power might be possible. StuRat (talk) 14:14, 19 March 2009 (UTC)[reply]
Might have to hold back on the lunarthermal energy, the quoted values for heatflow from the Apollo program are somewhat less than the average for the earth and the average is not enough to make geothermal energy a viable option (aside from heat pumps). As far as reaching a liveable temperature, I would guess just being below the direct influence of the diurnal temperature variation would be sufficient. Mikenorton (talk) 14:56, 19 March 2009 (UTC)[reply]
That and isnt the traditional method for geothermal energy involve large quantities of water to convert into steam? Something the moon lacks. 65.167.146.130 (talk) 15:24, 19 March 2009 (UTC)[reply]
I'd say that density has an effect on it too: Neptune's density and core temperature are both higher than Uranus', for example. ~AH1(TCU)17:29, 19 March 2009 (UTC)[reply]
Stents
Hi does anyone know why stents, e.g. those used to counteract constriction of the common bile duct; are mesh like in appearance? Why are solid lumps of metal not used instead? Is there any point in them having a mesh structure? Thanks. —Preceding unsigned comment added by 139.222.240.225 (talk) 11:41, 19 March 2009 (UTC)[reply]
I would guess the mesh stints are flexible and move with the tissue better. I think its also good to minimize the amount of foreign matter in any body. The mesh stints can also be compressed while they are being put in place and then allowed to expand to their working dimensions.--OMCV (talk) 12:12, 19 March 2009 (UTC)[reply]
One reason may be that the mesh tubes are somewhat flexible (as noted above), a second one would be that the gaps allow for the continuing function of the walls of the duct and prevent some atrophy of a small section of the relevant passage (coronary, urinary, etc). --Cookatoo.ergo.ZooM (talk) 12:16, 19 March 2009 (UTC)[reply]
Stents have to be cylindrical to allow normal flow through the vessel (or duct) where they are located. They are inserted using a catheter that has a balloon around which the stent is wrapped. The balloon is passed into the narrow section, inflated, and then deflated leaving the stent to maintain the enlarged diameter. If solid-walled, the balloon would have to actually stretch the metal. Instead, the balloon just bends the metal mesh stent to conform to the wall of the vessel/duct (the length of the stent decreases as the diameter increases). --Scray (talk) 12:41, 19 March 2009 (UTC)[reply]
Help Me! I am stuck on some issues about Evolution
Evolution does away with God. No God. I then worship myself, doing whatever I want owing to no one.
Evolution does not happen around me. I have never seen a chicken turn into a dog.
I frequently see gaps in evolution. “Dino dung contains grass”.
About the dino bird: Why on earth does a dino turn into a bird.
Why do anything when the universe is just going to go kaboom in a billion years.
The Creation “myths” seem alright with me because I know Volcanoes and Floods can create what Evolution scientists claim to have taken millions of years.
The Bible is bullied.
People use evolution for racist ideas. Evolution seems to allow racism. Compassion only came into existence because of chance. The Bible is also used to allow racism, but I read that we are to love every one as ourself. None of the: “I just evolved, no point in life, don't need to love coz love just evolved”.
DNA does not grow on trees. My science teacher recons that the only way to gain more DNA so I can grow wings is to ask God for it. [Year 11 student in Perth, Australia] —Preceding unsigned comment added by 60.230.212.29 (talk) 11:45, 19 March 2009 (UTC)[reply]
You have a lot of questions there, and it might help to organize them better, say as a numbered list, if you expect answers to all of them. Also, evolution says nothing about the existence of God, just that God isn't necessary for the step of one species evolving from another (although you could still argue that God controls mutations). God may still be used as the cause of the Big Bang, etc. God (or "the gods") used to be thought of as doing everything, from making day and night to the seasons, but we now know that is all just a consequence of the Earth's rotation and revolution. In another example, we now know that the variation in children in a family is due to random combinations of DNA in chromosomes. StuRat (talk) 12:04, 19 March 2009 (UTC)[reply]
Let me say that it's really poor logic to conclude that anything you haven't witnessed personally doesn't exist. Also note that this would apply to everything in the Bible, unless you're a lot older than you seem. :-) StuRat (talk) 12:27, 19 March 2009 (UTC)[reply]
As for gaps in evolution, they are relatively small, and closing all the time as we find more fossils. Gaps in the Bible are absolutely huge, on the other hand, and not getting any smaller. For example, how did we get from Adam and Eve to all mankind ? Was there a lot of incest (as opposed to a Lot of incest) ? StuRat (talk) 12:31, 19 March 2009 (UTC)[reply]
As for your "Why do anything when the universe is just going to go kaboom in a billion years" (it's actually many billions), the same is true in the Bible, only on the order of thousands of years, isn't it ? That nasty Armageddon bit in Revelations ? And in billions of years, who knows, perhaps we will be able to travel to parallel universes which aren't about to die. StuRat (talk) 12:21, 19 March 2009 (UTC)[reply]
You said "Volcanoes and Floods can create what Evolution scientists claim to have taken millions of years". You seem to be confusing evolution with geology. There are some geological formations which are formed quickly, yes. There are others which take millions or even billions of years to form. Plate tectonics is a good example of the later, where the continents all used to fit together. In some cases, it's obvious just by looking at them that they once did. The rate at which they are moving tells us it took many millions of years for them to get where they are now. Rates of radioactive decay also tell us that the oldest rocks on the Earth are around 4.3 billion years old. StuRat (talk) 12:51, 19 March 2009 (UTC)[reply]
To take on another of your Q's, let's talk about why a dinosaur might evolve into a bird. First, feathers are useful for flight, but also provide for good insulation. There are many flightless birds, like penguins, which use them for insulation. Next, flaps of skin can develop on arms to allow for longer jumps from tree to tree or on the ground. This has happened in flying squirrels, too. Then, once these basic items are in place, even a small improvement can allow for longer jumps or glides, both of which are helpful for survival. This eventually leads to all the birds. StuRat (talk) 12:14, 19 March 2009 (UTC)[reply]
If you pray to God for wings, and they sprout out and you fly away, then, by all means, believe in God. If that actually happens, I may even join you in your beliefs. StuRat (talk) 12:46, 19 March 2009 (UTC)[reply]
Neither evolution nor the Bible can be used to define a moral code. Evolution says nothing about morality. The Bible says a great deal; so much, in fact, that it has parts that can support any moral code you want, from slavery, genocide, and hate crimes against homosexuals, to the oppression of women. So, in either case, you come up with your moral code on your own, and only use evolution or the Bible to justify what you already believe. StuRat (talk) 12:42, 19 March 2009 (UTC)[reply]
Evolution does away with the literal interpretation of the bible god; it does away with the YEC's god, but evolution has little to say to millions who have compartmentalized enough to conform their mythos to the real world. Inductive logic is what does away with god. But based on your post, I'm wasting my breath. You need to take evolution in baby steps. Start with biology 101 and move progressively. I doubt that will happen but the problem is that you're so lost in the fundamentals, your knowledge of the subject so narrow, that you can actually say something like "I have never seen a chicken turn into a dog." By saying this you show that you have no understanding of evolution at all. Not even the tiniest scintilla, but have some one or two sentence idea of "things turning into other things for mysterious reasons" that is called evolution. The poster above is trying to be helpful but he's skipping the part where we sit down with you for months and months teaching you the basics so you have the slightest understanding to put his post in context.—70.19.64.161 (talk) 12:30, 19 March 2009 (UTC)[reply]
If you "know" that volcanos and floods can cause things that scientists say take millions of years than you're mistaken. Perhaps you're thinking of a common claim that the Grand Canyon could have been created during the Great Flood. This doesn't even stand up to casual examination by a layman. A massive amount of water unleashed at once would cut a wide, shallow swath, not a sharp deep one like a canyon. (And of course, once it's completely covered, even this effect would slow greatly.) You can verify this in your backyard with a large tub of water and a garden hose.
"My science teacher recons that the only way to gain more DNA so I can grow wings is to ask God for it." He is right. The only way you -personally- will will gain additional DNA is divine intervention. Evolution is caused by children having slightly different DNA than their parents. Once you're born you're stuck with whatever DNA you've already got.
"Why do anything when the universe is just going to go kaboom in a billion years." Frankly, I've always thought the answer to this is : "To see how much cool stuff we can do before then." APL (talk) 13:24, 19 March 2009 (UTC)[reply]
In the form of fruit, no doubt. As for sprouting wings, eventually scientists may be able to use a virus to insert genes (to grow wings) into our DNA. However, the wings we would grow would only be decorative. To make a human capable of flight would require a total redesign of our entire body, including tiny legs. StuRat (talk) 13:54, 19 March 2009 (UTC)[reply]
You say on the first line without God you would do what you want owing to no-one. Have you asked yourself if there really is anything much different you would actually do without God looking over your shoulder? Or are you thinking that other people would behave any differently? Dmcq (talk) 14:19, 19 March 2009 (UTC)[reply]
On the subject of sprouting wings. There is a slight problem with the fact that the Angel type of construction basically adds another set of limbs when compared to ordinary things with wings like birds or bats. You'd not only need divine intervention to get wings, you'd also need a constant miracle to move them or would have to add a rather unsightly hump to your ordinary back. Artist pictures don't show any muscles needed to move the wings. (Not to mention the joint that connects them to the body). I assume they are just a decorative appendage and your divine entity would actually provide for Levitation. 76.97.245.5 (talk) 14:57, 19 March 2009 (UTC)[reply]
Oh my - what a lot of questions. Well, now that you've asked so many - you are honor bound to slowly read through ALL of my carefully thought-out answers! No cheating and skipping the ones you don't agree with!
Evolution does away with God. No God. - Not precisely. Evolution does away with the need to use god or gods to explain how we came to be. You are still at liberty to assume that god(s) made the world in one night on September 12th 1962 - and just made it all "look" like there was evolution. It's a pretty crazy thing to believe - but if you've gotta have a god to sleep at nights - there you go.
I then worship myself, doing whatever I want owing to no one. - Well, you COULD - but you live as a part of society that imposes rules in order to make life bearable - and if you do literally "what you want" - then the odds are good that other people will get pissed about it and you'll find that you are physically unable to continue doing what you want. Societal pressures to behave according to the norms are considerably more effective than religious pressures simply because the punishment or restraint is immediate and vastly more certain. I'm fond of pointing out that the Bible is the most shop-lifted book in the USA. Clearly people who are going into bookstores and stealing them aren't afraid of divine retribution.
Evolution does not happen around me. I have never seen a chicken turn into a dog. - No, but if you lived in New York, you'd have seen rats turn into Warfarin-resistant rats that thrive on eating rat poison. If you worked in a hospital, you'd have seen tuberculosis-causing-bacteria turn into tuberculosis-causing-bacteria-that-you-can't-kill-with-antibiotics. The process is relatively slow. However - (for example) humans appear to have evolved to become lactose-tolerant over a space of a few thousand years - and the process isn't complete yet...that's truly evolution in action. There are MANY cases where evolution can be observed happening for real right in front of your eyes in a test-tube. But to change a chicken into a dog might require millions of years of evolution - and that's something you obviously can't see happening before your very eyes. Just because a process takes a long time isn't a reason to assume that it's not true. It took a long time for a relatively small river to carve out the Grand Canyon...but we don't go around denying that this is how it happened.
I frequently see gaps in evolution. - no you don't. You frequently hear like-minded "intelligent design" idiots CLAIMING that there are gaps in evolution. You've never personally spotted one. In fact, science is still plugging holes - finding fossils isn't something you can do "on demand". If you don't happen to have a fossil that shows something halfway between a smooth-skinned fish and one with scales doesn't mean that there is a horrible "gap" that completely blows away the theory - it simply means that nobody has yet found a fossil of that particular animal. Because we HAVE found long chains of very similar animal fossils that DO show continuous, gradual, gapless change from one species to another - we KNOW for 100% certain that those particular species evolved. And with every 'chain' of fossils we find, the gaps get smaller and less frequent - but to expect to have complete evidence for the pathway from every single creature to every single other creature is stupid. There comes a point (and we're WELL past it) where the evidence is simply overwhelming and the gaps are perfectly explicable. "Absence of evidence is not evidence of absence."
About the dino bird: Why on earth does a dino turn into a bird. - Because of some sort of evolutionary pressure. If running along the ground is too dangerous because of predators (say) then maybe a small genetic change allows the creature to have the musculature to climb trees. That creature does better than the earth-bound dinosaurs - so it survives when the ground-based ones are all eaten by predators. However, the ones in the trees still have to climb down out of one tree and up into the next - so they are vulnerable still. If one baby tree-dino happens by luck to have genetically stronger legs and can jump from a tree to another nearby - it'll spend less time on the ground and it (and it's offspring) will thrive while the ones that have to climb down don't. Now, they only have to go to the ground to get from one clump of trees to the next. But if they evolve a flap of skin or feathers and lighter weight bones - they'll be able to glide between trees that are still further apart. Then they may evolve powerful muscles to allow them to flap a bit. Before you know it (and over half a million years) you have birds. Then something happens to all of the predators (like maybe a meteorite kills them all) and the birds have no more predators on the ground - so evolving to be more capable on the ground so you can eat stuff you only find down there - makes sense. Now you have flightless birds like chickens. When the predatory mammals come back - they evolve into ostritches that can kick the hell out of a predator...and so on and so on.
Why do anything when the universe is just going to go kaboom in a billion years. - Indeed, why? Guess what? It's evolution again. If a bunch of humans got it into their silly heads that they should just lie in bed until they die because life is pointless - then they'll fail to pass their crappy genetic makeup onto any children - so only the kids of the people who suck it up and try to make something of themselves will survive into succeeding generations. Before you know it - we've evolved a powerful drive to survive - to have children and to look after them. Hence we are genetically PROGRAMMED not to shrug our shoulders and give up on the world.
The Creation “myths” seem alright with me because I know Volcanoes and Floods can create what Evolution scientists claim to have taken millions of years. - Bullshit. Please explain how a volcano or a flood turns a dinosaur into a chicken? I explained how evolution can do it. What you are REALLY saying is that this is all too hard for your tiny little brain and you're too stupid to think for yourself so you'd rather be spoon-fed a bunch of nonsense than to actually examine how the universe works - look at the evidence - take your sorry ass down to the nearest decent natural history museum and ASK one of the curators if they can show you some fossil sequences to help you to understand. Nope - it's better for you to have some idiot in a silly costume get up there on a sunday morning and tell you that it all happened by magic. Well, good luck with that!
The Bible is bullied. - The Bible is WRONG. I've actually read the Bible - not just a verse here and there as instructed by some Sunday school teacher. I started at page one and read it all the way through - like a real book. It's CRAP! It's self-contradictory, inconsistent, flat out unbelievable. It starts off with this rabid lunatic of a god who does the nastiest things imaginable for the smallest reason - to someone who is supposed to be kind and caring and it's all rainbows and unicorns. You actually have to read the book with open eyes to see what a pile of steaming crap it really is.
People use evolution for racist ideas. Evolution seems to allow racism. - I don't understand why you'd say that. People have certainly used the Bible to promote racist ideas. Just take a look at the KluKluxKlan nut-jobs! They are passionately religious - and equally passionately racist - and they justify every word of their racist nonsense from the Bible.
Compassion only came into existence because of chance. - Actually, there is evidence that compassion and being nice to people and stuff like that is evolved too.
The Bible is also used to allow racism, but I read that we are to love every one as ourself. - And I read (in the Roman Catholic/Lutheran bible - the first of the 10 commandments - that if you worship an idol - your children, grandchildren, greatgrandchildren and great-great-grandchildren will be punished. Sheesh! So if my great-great-grandfather was worshipping idols - I get punished for it!?! Nice god! The bible also says that if your son swears at you - you should kill him. (Although you aren't actually ALLOWED to kill him...hmmm tricky). Really - it doesn't stand up to close examination.
None of the: “I just evolved, no point in life, don't need to love coz love just evolved”. - Nobody who believes evolution to be true says that. We have EVOLVED to have point to our lives. Heck - I'm an out and out atheist - I love life. I had fun as a kid learning stuff - I loved - I married (although a civil contract would have been OK by me). I have a son - we enjoyed bringing him up right - teaching him moral values - things that make society run well "Don't kill people - don't steal things - but go ahead and covet your neighbours ass - I don't give a damn about that". We've EVOLVED those concerns because we're a tribal society. Getting on with a village of people is how we're programmed to be. Passing our DNA onto the next generation is something we're powerfully driven to do. Anyone who didn't have those drives - passed on in their DNA from their parents - would not have children of their own - their DNA would not get passed on. So only the people with genes that give them the drive to have children get to pass their DNA on...so after not too many generations, pretty much everyone wants kids - most people like raising them. It's evolution that does that.
DNA does not grow on trees. - yes it does! :-)
My science teacher recons that the only way to gain more DNA so I can grow wings is to ask God for it. - your science teacher is 100% correct in that! Certainly you can't "gain more DNA" by any known scientific means - you're absolutely stuck with what you were born with. If/when you pass your (and your partner's) DNA onto your children, their DNA will be a little bit different - and the DNA of THEIR children will be different still. If there is an evolutionary pressure for humans to sprout wings and fly - then perhaps over tens of thousands of generations, that MIGHT happen. Evolution is a slow process. So - if there is a god - you could certainly pray for DNA to grow wings with...and by all means try that. Pray your darnest...plead with God for those wings. Do you REALLY think he'll give them to you? I don't.
Soapboxing refers to a situation where someone pretends to ask or answer a question, but is actually just propagating his agenda (or, in some cases, doesn't even bother with the question part at all). Clearly, Steve is answering the original poster's specific questions, and doing a pretty good job of it, too. Yes, absolutely, you can also tell that Steve has opinions about the matter at hand, but he's not expressing them instead of answering the questions. -- Captain Disdain (talk) 19:30, 19 March 2009 (UTC)[reply]
As an aside, I will worship any god, demon, or other deity that gives me the capacity for free flight without any technological support. (I would prefer a pair of wings, but Superman-style flight would also have its advantages.) It goes without saying that I expect this ability up front before I start with the worshiping. I'm an atheist, But I can be bought. :-) APL (talk) 21:19, 19 March 2009 (UTC)[reply]
I'll join you in that religion, but if it's going to be superman-style flying someone had better give me a cape - I'd look stupid without one! --Tango (talk) 23:08, 19 March 2009 (UTC)[reply]
Might be unwise. The Lord giveth, and the Lord taketh away - and if He taketh away thy flying at 25,000 feet, thou art screwed. - EronTalk23:36, 19 March 2009 (UTC)[reply]
That's why sensible gods don't give all their rules in written form - it makes it too easy to find loopholes. If you keep the rules nice and vague you can make them fit the situation however you need. --Tango (talk) 23:39, 19 March 2009 (UTC)[reply]
The Bible is WRONG Hm Steve, what about the very first chapters of the Bible (and some other chapters) being just symbolic? One should read the Bible for it's moral teaching, it's not intended to be used as a science book. Too bad some zealots try to regard it (and try to enforce it) still as a science book, destroying the main concept behind it... and by doing so they are making religion to look ridiculous too. —Preceding unsigned comment added by 79.116.91.3 (talk) 01:19, 20 March 2009 (UTC)[reply]
You haven't read it have you? I tell you - start from page 1 and read to the last page...it's an education. The old testament is NUTS - yeah, yeah - it's all symbolic. So why the heck does it matter if it's just a work of fiction? I don't think the stories surrounding the ten commandments are intended to be symbolic. That bit is really pure slapstick - the guy spends an age up there chatting with god - chiseling the words into literal stone tablets - and when he gets back he drops them (oopsie!) and the break so and has to go back up to god and get another set...but this time, God has obviously lost his train of thought because the second set have completely different rules...this combined with a God who really needs to switch to decaf. SteveBaker (talk) 04:03, 20 March 2009 (UTC)[reply]
Symbolic or not, you can't just cherry-pick the parts that sound nice -- bring up the cuddly "let's all just get along" bits as proof of how wonderful moral guidance the Bible provides and ignore the crazy-ass "the hero of the story murders 200 people for their foreskins to prove his righteousness and get some poontang" bits.
But that is simply not what it says. The Old Testament is clearly full of commandments from God. It was also written hundreds of years before the New Testament, so clearly wasn't intended to be compared to it. --Tango (talk) 00:00, 23 March 2009 (UTC)[reply]
If the moral is contained in the New Testament, then you're cherry-picking. You're making a judgment call on what parts to glorify and what parts to ignore as insignificant. The problem with that is that if it's up to you to figure out what's right, then you're by definition following your own morality, not some great ancient divine wisdom. You can't have it both ways. (Anyway, the New Testament isn't that much better. It still advocates slavery and doesn't exactly say a lot of nice things about the value of women, for example.) -- Captain Disdain (talk) 06:20, 23 March 2009 (UTC)[reply]
Moral teachings as in "The most important thing for anyone to do is to cater to the megalomanic whims of their creator."? No thanks. --Tango (talk) 14:48, 20 March 2009 (UTC)[reply]
Just by the way, I can always, always tell when it's SteveBaker who is posting. Your style of writing, it's etched into my memory. Especially with allcaps for EMPHASIS (no pun intended). ~AH1(TCU)01:39, 20 March 2009 (UTC)[reply]
Evolution does away with God. I know of no serious student of evolution who would postulate such a thing. In fact, evolution ignores God, simply because one is science and the other religion. Or, if you insist on mixing the two, then simply acknowledge that there is nothing at all about evolution that is not compatible with a God. What it is incompatible with is creationism. Very different, unless you're a religious extremist. DOR (HK) (talk) 04:35, 23 March 2009 (UTC)[reply]
'I also have read the bible several times.'Some of the old testament reads like health suggestions.' Such as not eating pork.with no refrigeration and not knowing about food poisoning or parasites from uncooked or undercooked food, eating the meat of a scavenger(pig) could be deadly (Gods ultimate revenge)also, marrige would be a way to make the survival of children more likely. With multiple wives because of the high mortality during birth.etc. etc. etc. resource allocation for the in group, and damnation for the outgroup. Furthermore, the origonal poster does not take non Judeo/christina religions into accountHinduism, is older, and creationism according to the Rigveda, only vaguely says"there was nothing,then there was"Crazybearr (talk) 07:23, 23 March 2009 (UTC)[reply]
Wow, I have a bad day at school, go hiking for the weekend and come back and ... wow! Thank you to all the people who have contributed to this section, you are the people who make Wikipedia what it is. I have read through all your writing and even went so far as to observe other contributions made by every user. I am impressed. I will address Steve first since he answered me the most. Year 11 Student Perth, Western Australia 60.230.212.29 (talk) 09:03, 23 March 2009 (UTC)[reply]
Dear Steve, I studied your answers concerning evolution. However I cannot agree with you for most of it, and nor can my wise, and enjoyable, science teacher.
Their would of being a lot of what you call incest when there was only a few people on the Earth. But back then it was not considered bad because their was no side effects, with perfect genes there was no problem medically.
20 years ago people scoffed at the Hittite civilisation that the Bible describes. Look it up and you will find that they are as real as the brain in your head.
I vote the the page named Introduction of Evolution should be changed to Introduction of Specialization. Even so, the evolution page is quite confusing.
Sorry for confusing you on my Volcanoes and Flood thing. What I meant to say is: “Volcanoes and floods can create and destroy what you believe to have taken millions of years?” Your are not telling me that radioactive decay can actually correctly tell me the age of a rock. I have sand and plants in my garden. If, say, I decide to test your experiment in my garden, with unlimited and copious amounts of water, it would go like this. Firstly the plants will be uprooted because the top soil is being washed away. The plants will still survive in the water, almost the same thing as hydroponics. Then the rest of the soil will wash away, causing a massive hole in my garden, likely a few other gardens and houses as well and a large river. A lot of water has been consumed. I am now using a massive hose pouring thousands of litres on my former garden. The water starts to erode the bedrock and has turned into a flood. A canyon, not half the size of your impressive Grand Canyon, has been formed.
Show me pictures of the in betweens that Evolutionists claim to have existed and did actually exist. Your description of the Dinosaur turning into a bird made sense. But show me some pictures of these dino-gliders. I am interested. But you can also tell me how something as complex as the human eye evolved, just like you told me about the dinosaur evolution. Do not worry about being to scientific for me.
Evolution says to God “We do not need you to explain how we came into existence” Precisely does away with God.
About your statement involving the fact that the Bible is the most stolen book in the world. Well, think about this medicine is stolen with out thought that it is wrong, they need to save themselves or someone else from sickness.
Hitler, Lenon, and Darwin are all people who have used evolution as an excuse for racist ideas. Darwin wanted Australian Aboriginals skinned and sent to him so he could study what he thought mistakenly thought of as a missing link. Hitler thought that his exterminations of Jews and his Master Race breeding program were just helping evolution go faster. Lennon authorised an experiment on African people and monkeys so he could create a half monkey half human slave army because monkeys are “related” to us, and therefore might just be able to breed with us. African people, according to the evolutionary idea are lower on the evolved scale.
My statement concerning DNA growing on trees was small and was taken light-heartedly. DNA can be copied, mistakenly copied, lost (As in the case of your New York rats and bacteria, which is unfortunate to hear about.), but NEVER found, created or gained. Imagine a computer program, it had to be PROGRAMMED, right? This particular one is programed to copy itself. It is not on a perfect computer so data is lost and corrupted when it copies itself again and again. Sometimes those corruptions and lost data are good for it because the computer is always changing. How can something as complex as even a computer program evolve, how did it get there gradually? It could not.
Coveting my neighbours ass is disrespecting her. I do hope your child is not disrespectful, just like you were to me. Calling my friends stupid, my religion crap and putting down what I believe in. But I will not hold that against you or Charles Darwin.
If you believe the Bible, yet say that some of it is wrong, then, how can you believe in the Bible? If the Bible just contained people that were all cherry then would the Bible still be believable. The Bible contains a whole lot of information about David, second king of Israel, not all of it is good, he was not perfect, but the Bible is.
In telling me that I am just PROGRAMED to live, that evolving and procreation is my only objective, that compassion and being nice to people just evolved, and that I can make up any moral code I like, then you have given me an excuse to commit suicide. But fortunately I have no desire to do so. Being a Christian not only helps me sleep at night but gives me a true purpose, not just something that has evolved and will evolve again. I can see a rainbow and know who to thank. I know that God loves me and made me special, just like he did for you. God would rather you believe in Him because you LOVE Him, not coz of fear or coz He can give you wings.
Evolutionist - nothing to lose if there is no God
Christian - nothing to lose if there is no God
Evolutionist - eternity to lose if there is a God
Christian - eternity to gain if there is a God
Then can you please show a better answer to why I should continue living. If I believed in evolution that is.
Year 11 Student Perth, Western Australia 60.230.212.29 (talk) 09:03, 23 March 2009 (UTC)[reply]
I usually refrain from answering questions about evolution because the discussions never seem productive. However, there are several egregious comments that need to be addressed here:
"African people, according to the evolutionary idea are lower on the evolved scale" -- This is an utter misrepresentation of evolution, and no honest person who truly understands the underpinnings of evolution would say such a thing. This would be like you saying that your 2nd cousins are "lower" on the "evolved scale" (whatever that is) than you are. Where on earth did you get the idea that evolution somehow ascribes a "higher" or "lower" degree of "evolved"-ness? This is utter nonsense.
"...you can also tell me how something as complex as the human eye evolved" -- This is a common argument by proponents of "irreducible complexity" as some sort of "proof" that evolution does not occur. It may be true that we don't have a complete explanation for every single step in the process (yet), but it is pretty self-evident if you start to actually think about the problem that evolution of the eye is no different than any other part of the body. Others have already addressed these examples in great detail. Read the article on irreducible complexity. Understand what is being argued. There is no "proof" to be offered in simply stating that something is "too complicated to understand". It is lazy, non-scientific nonsense.
"In telling me that I am just PROGRAMED to live, that evolving and procreation is my only objective, that compassion and being nice to people just evolved, and that I can make up any moral code I like, then you have given me an excuse to commit suicide." - this is a very bizarre interpretation of what evolution teaches us about life. Why do you use the example of suicide? Evolution doesn't give you an "excuse" to do something. It just explains how natural selection might act over millions of years to shape the behaviors exhibited in a species. We have eons of evolutionary history that selected for adaptive features, including fear, aggression, lust, greed, etc. etc. etc., yet our brains have also evolved over millions of years to excel at problem solving and therefore logic, and by logic human societies can arrive at reasonable standards of behavior that allow all of us to thrive and co-exist despite our most base instincts, therefore improving everyone's ability to pass on their genes. That some members of society do not comply with these standards of behavior, and cheat others for their own gain, is part of the evolutionary process as well (and not always rewarded over the long-term). That suicide exists is also part of the evolutionary process. If you know anything about cell biology you will recognize that there are well-regulated programs for cells to commit suicide. This process is fundamental to developmental biology and actually prevents cells from becoming cancer if they are malfunctioning -- cell suicide is therefore quite adaptive at the level of the whole organism. At a higher level, I would argue that evolution has endowed our species with a great aversion to suicide (otherwise we'd no longer exist) and that only under extreme circumstances do people consider this option. How does this conflict with evolution?
Alas, I have spent too much time responding and I fear that I may have been feeding the trolls. You will either spend time using your brain to consider these points, or you will simply be lazy and accept what you are told to believe. Life is yours to do with what you will. --- Medical geneticist (talk) 15:19, 23 March 2009 (UTC)[reply]
20 years ago people scoffed at the Hittite civilisation .... Did your preacher say who scoffed? I have here a dictionary published in 1950 – yup, a rather long entry about the Hittites, their history, their ethnic affinities, and a mention of the decipherment of their language.
You are not telling me that radioactive decay can actually correctly tell me the age of a rock. Yes, that's what (whoever) is telling you. Would you like to know how?
Show me pictures of the in betweens that Evolutionists claim to have existed and did actually exist. Yah, so you can demand fossils between those and their neighbors? Show me a picture of the missing link between you and your mother.
Evolution says to God “We do not need you to explain how we came into existence” Precisely does away with God. Only monotheists, it seems to me, are so hung up on creation. Polytheists have their creator-gods, but the creator usually isn't the most important one in the pantheon. Does evolution do away with their other gods too?
Hitler, Lenin, and Darwin are all people who have used evolution as an excuse for racist ideas, bla bla bla. Can you point to any belief of any kind – religious, scientific, political, aesthetic – so pure that no wicked or misguided person ever adhered to some version of it?
Imagine a computer program, it had to be PROGRAMMED, right? ... How can something as complex as even a computer program evolve, how did it get there gradually? It could not. You might find genetic programming interesting.
I do hope your child is not disrespectful, just like you were to me. Calling my friends stupid, my religion crap and putting down what I believe in. Why should anyone be more respectful to your religion than you are to science?
Then can you please show a better answer to why I should continue living. If I believed in evolution that is. Well, I continue living because I haven't seen all the beauty that I might see – or make.
Technically, I should put this on Steve Baker's talk page but I can't figure out how.
Anyway, I enjoy Steve's responses and find them most informative. HOWEVER, his attitude toward the original poster was rude and condesending. I found it hard to focus on his arguements when his disrespect was so blatant. Steve: you owe the guy an apology. I guess you must have had a bad day.
Soami Oil?
I was at a trendy restaurant yesterday and they served a salad dressing made of balsamic vinegar and "Soami Oil". Surprisingly, no one could tell me what Soami Oil is. And there is no entry for it on Wikipedia. Any idea what it is? And is it even legal to serve a substance that no one can define? --67.66.110.148 (talk) 15:15, 19 March 2009 (UTC)[reply]
Another very long shot, there's a company in Pune, India called 'Swami Oil Industries', that appears to make edible oils. Mikenorton (talk)
Laser safety
Is there something wrong with the graph at the start of Laser safety#Maximum permissible exposure? As I am interpreting it, the longer that you are exposed for, the higher the dose you are allowed to receive. That seems completely backwards. The second graph looks much more sensible. Should I just delete the first one? -- SGBailey (talk) 15:57, 19 March 2009 (UTC)[reply]
I haven't checked to see if it agrees with the source, but it seems to make sense. It's a graph of total energy absorbed (per square centimetre of eye) against time, so it's saying that the more total energy you absorb, the more time this dose has to be spread out over for it to be safe. Algebraist16:14, 19 March 2009 (UTC)[reply]
Indeed. The difference between the two graphs is that the first is talking about energy density (J/cm2) and the second power density (W/cm2). The same amount of energy over a longer time is less dangerous because it corresponds to lower power. The same power over a longer time is more dangerous because it corresponds to more energy. --Tango (talk) 16:23, 19 March 2009 (UTC)[reply]
I've often heard that the mathematics behind string theory is really, really, really complex and that few can interpret the equations, let alone understand it. Could anyone provide an example of where I can see this stuff? I don't intend to try and understand it, I'm just curious to see how complicated we're talking here. —Cyclonenim (talk · contribs · email) 17:46, 19 March 2009 (UTC)[reply]
Hi. Recently on the non-residential sub-urban streets, especially those with lots of large trucks and side-road sand, I've noticed a particular strong and intermittent smell. It smells rather like three parts glue, two parts rubber, one part latex, one part chlorine, one part automobile exhaust, half a part paint, half a part sand and asphalt, half a part vinegar, a quarter part garbage, and a quarter part gasoline, co-mingled together. Sorry about my confusing decription, but I find it easiest to compare unidentified olfaction to other smells, and idea what it is or what causes it? Thanks. ~AH1(TCU)17:54, 19 March 2009 (UTC)[reply]
It could be the asphalt they use to plug potholes. Is there a lot of black patches on the road that look like shiney black glue mixed with rocks? Livewireo (talk) 19:51, 19 March 2009 (UTC)[reply]
It may not be entirely out of the realm of possibility that you are smelling exactly what you have described depending on the surroundings. Truck exhaust, asphalt, garbage haulers, and any typical manufacturing facility (if there are any close by) can all be adding to the mix. cheers, 10draftsdeep (talk) 20:27, 19 March 2009 (UTC)[reply]
Here in North Carolina, lots of trees are in bloom right now, and many, like the Dogwood and Bradford pear trees in my neigboorhood have a rather pungent smell. It reminds me of methylamine sorts of smells (mildly like rotting fish), but lots of blossoming trees do give off odors that many people find unpleasant, like this one. Or it could just be all the stuff noted above. --Jayron32.talk.contribs00:02, 20 March 2009 (UTC)[reply]
Are you talking gravel roads or paved? And what's your current thaw state? It could be patch asphalt (per Livewireo, you will see the patches), it could just be a winter's worth of crap melting and starting to rot/vapourize. And they may be putting non-clumping agents in the sand spread all winter too. I always found in Ontario that you could call up the local Works Department and they would be happy to answer questions and/or go check it out. Franamax (talk) 21:36, 20 March 2009 (UTC)[reply]
My friend is suffering frm sinus infecion.....he drinks a lot of cold drinks..but at d moment he is suffering frm hi fever nd head ache.
he consulted a doc. nd he said he has got cough depostied in his head.
the doc. has given him medications. and said if these dont work....he needs an operation.
i m a bit scared .is it something serious or is it ok....?????????
pls suggest me wid something......... —Preceding unsigned comment added by Sweetgirl290608 (talk • contribs) 18:39, 19 March 2009 (UTC)[reply]
We are not medical professionals here and we can't give medical advice regarding how serious your friend's case may or may not be. For general information about sinus infections, you should read the article on Sinusitis. - EronTalk18:45, 19 March 2009 (UTC)[reply]
I've been trying to get a prescription of focalin refilled for about three weeks. They pharmacies say they haven't been able to get it and no one else has either. I asked if it had been recalled and they said no. Is there a shortage? Did they quit making it? Why aren't they able to get it?
You should ask your doctor for help. S/he probably has samples of the drug that can tide you over until you can get a supply, and also contacts in the drug industry who will be very motivated to get you back on their product. You can also legitimately order scheduled drugs online after doing some paperwork. --Sean19:42, 19 March 2009 (UTC)[reply]
I had always assumed the huge old wooden doors with the rusty metal hinges were made of oak and iron, but I recently discovered these two materials don't work very well together. What actually happens if they are put together, and what do people use instead?
148.197.114.165 (talk) 21:16, 19 March 2009 (UTC)[reply]
Brass is a possibility. Wrought iron surface is different from cast iron. Annealing doesn't mention it, but this article does [10]. Not sure whether that would affect how it interacts with oak. Since oak was used for tanning presumably before it was used for doors, people probably knew about it's properties. AFAIK oak was often soaked and dried before it was used in construction. They also used pitch as surface treatment. My money would be on the Tannins in the oak wood eating your iron. Some of them are acids. 76.97.245.5 (talk) 22:26, 19 March 2009 (UTC)[reply]
I'm not familiar with the details about how they would react, but I would note that common writing ink until very recently was iron gall ink, made from iron compounds and tannin rich oak galls. -- 76.201.156.15 (talk) 03:32, 20 March 2009 (UTC)[reply]
Iron through wood accelerates the decomposition of the wood by feeding bacteria an essential element in short supply. Also you get the black staining due to the iron tannin compounds. Graeme Bartlett (talk) 05:22, 20 March 2009 (UTC)[reply]
I am currently studying organic chemistry, and I was curious how this particular synthesis could be accomplished. These are the steps I used, and I would like someone to tell me if they are correct. No, this isn't a homework problem, I was just curious how this could be accomplished. I know it's not the most economical way to synthesize it; I was just curious.
1)I used Friedel-Crafts alkylation (CH3Cl & AlCl3) to add a methyl group.
2)I added a diazonium group to the para position using NaNO2 and HCl.
3)I added PCC to oxidize the methyl group to an aldehyde. I'm not sure if I used the right oxidizing agent here.
4)I brominated the compound with Br2 and FeBr3.
5)I replaced the bromine with a methoxide group by adding sodium methoxide.
6)Finally, I converted the diazonium group to a hydroxyl group by adding an aqueous acid (H3O+).
CalamusFortis21:59, 19 March 2009 (UTC)[reply]
PCC may not work. PCC generally is specific for taking alcohols to carbonyls. I don't think it is strong enough to take a simply alkyl group all the way to the carbonyl. The other steps look OK, so long as the methoxide will not also substitute the diazonium. You may also want to protect your aldehyde once it is made; else you may end up with unwanted side reactions like the Aldol condensation. See Protecting group for more info on this. --Jayron32.talk.contribs23:47, 19 March 2009 (UTC)[reply]
I see a few problems here, especially if this needs to be any sort of practical (vs "looks possible on paper") approach:
1 Getting a methyl electrophile is probably pretty hard (think about stability of carbocations). Might work, but would be easier to put on...well anything else. Given that you're going to oxidize it, could even be an ethyl or isopropyl, since those additional carbons can be cleaved in step 3.
2 To get diazonium (Ar-N2+), you use those reagents starting from Ar-NH2. For a simple aromatic, those give you the nitroso (Ar-NO). Which could be reduced to the amine.
3 Jayron is right...PCC only oxidizes alcohols well. Need something stronger and mechanistically different for benzylic position (I think KMnO4 is standard).
4 Your ring is *very* electron-deficient at this point (diazonium and aldehyde are electron-withdrawing) so doing another electrophilic aromatic substitution is probably too slow to be practically useful. And I don't think you would get good positional control. Diazonium is probably a strong meta-director and you want to Br go ortho to it.
5 Given how electron-poor the ring is (now with 3 inductively withdrawing groups!) an addition/elimination mechanism for this substution might work, but it's clearly *not* an SN2-type displacement and you have the risk of forming benzyne and then getting the nucleophile adding at a different position. Heck, you've got the diazonium too, which is a much better leaving group. Although it might be unlikely for it to have stayed attached this long.
Overall, might be better to activate the ring first as aniline, then put the para and then ortho substituents on (the NH2 would make the electrophilic reactions go faster whereas diazo and carbonyl each make it go slower), and last diazotize and convert to the hydroxyl. DMacks (talk) 00:04, 20 March 2009 (UTC)[reply]
It should also be noted that synthesizing ANYTHING from benzene is pretty much a pointless exercise; benzene is fairly chemically inert, and substituted aromatic compounds are readily availible. It's about as useful as synthesizing anything with only methane as a starting material. It is theoretically possible, but practically pointless. Our article on Vanilin gives numerous other synthetic pathways to make it, and none are as convoluted as taking it from unsubstituted benzene. If this is a homework problem, I sympathize with you, and say that you should have enough between your initial ideas and those of myself and Dmacks excellent additions to put together a workable synthesis; just know that this is a purely academic exercise; no real chemist would do it this way... like, ever... --Jayron32.talk.contribs02:54, 20 March 2009 (UTC)[reply]
Free will
Everything is life is subject to the laws of physics, and therefore act accordingly. If you drop a rock it will fall down, if you flip a coin it will fall with some outcome. My question is, isn't everything predetermined? Because everything I do, every action every human being and object does in the world is because of the laws of physics. Am I right in saying that if you flip a coin, flicking it with your thumb with a specific amount of force in a specific environment (something like wind, no wind, rain) everything happens because of physical interactions (e.g. a drop of rain falling on the coin) and could only happen in one way. What I wanted to know, is this true? Is there anything in nature that's random? Is there anything that, given the same environment, given the same forces and objects at the same time- would result in something... else? Can two occurrences that are completely the same in every possible metaphysical (I don't know what that word means, it just sounds smart) manner end up.. not being the same?
I hope I've gotten my point across, what I basically mean to ask "is there anything in life that is really random". I don't have much knowledge of quantum mechanics but I've heard that on a quantum level random things do occur, but my question is whether they are really random? To someone like me who doesn't know much about quantum mechanics, it seems impossible that two coin flips that are the same and are affected by the all the same forces and hit the exact same table on the same place should produce different results. If so, how can there be free will if every action we take is because of some chemical or physical reaction in our environment or bodies? --BiT (talk) 22:31, 19 March 2009 (UTC)[reply]
I would like to add that despite the fact that your line of thought is quite common, I find it very puzzling. I see free will as a sentient being's ability to make good choices given the circunstances. Good choices are more often based on logic than on randomness. Dauto (talk) 23:15, 19 March 2009 (UTC)[reply]
No - there are at least two or three reasons why things aren't predetermined...firstly there is quantum randomness - secondly there are chaotic systems. Both of these things guarantee that at least in some situations you can't predict the outcome of some future event with perfect certainty. At least once during the infinite life of an infinite universe, all of the molecules in your rock will spontaneously leap 6" to the right and not fall as you expected. Well, OK - that's pretty rare - but there are certainly 'macro-scale' things that you can't predict. There IS perfect randomness.
However, I don't think you can parley "randomness" into "free will". I don't think we have free will...quantum randomness and chaos theory notwithstanding.
SteveBaker, I agree with you that quantum randomness is a red hearing in discussions about free will. What I don't understand is why so many people equate determinism with lack of free will. As I see it, exactly the opposite is true. Total randomness destroys free will and determinism preserves it. Dauto (talk) 05:50, 20 March 2009 (UTC)[reply]
I find it rather difficult to define "free will". It requires a concept of conciousness that is somehow outside of science in order to make any sense. --Tango (talk) 23:37, 19 March 2009 (UTC)[reply]
It's a common misconception that true randomness can be found in chaos theory. In fact it cannot. A quick read of our own article will show that these systems "appear to be random" and "this happens even though the system is deterministic". Chaos theory is about systems where the tiniest deviation in the starting condition can produce huge changes in the end condition, which makes them practically impossible to predict, but they are in principle predictable. DJ Clayworth (talk) 23:38, 19 March 2009 (UTC)[reply]
I strongly disagree. Chaotic systems might be predictable in principle - but only if you have literally infinite precision in the measurement of initial conditions....but you don't...you CAN'T - you don't have enough paper to write down all of the digits of data to put into the calculations - and there isn't enough energy in the visible universe to crunch the numbers. Even without resorting to "oh no - you can't measure things that accurately because that nice Mr Heisenberg said 'No'."...a completely classical system can be literally impossible to predict. SteveBaker (talk) 03:32, 20 March 2009 (UTC)[reply]
When we're talking about a philosophical subject like Free Will, the question is "is the future determined" not "can we predict the future". Chaotic systems are determined, whether or not we can predict them. I would submit that to deny that the future is determined we have to invoke Heisenberg and quantum; chaos theory won't do it. DJ Clayworth (talk) 14:13, 20 March 2009 (UTC)[reply]
Well - I suppose at that extreme (both of logical position and linguistic interpretation!) - you are right for truly 'classical' systems when you are only talking about predetermination and not prediction. But - of course - there are quantum effects that are truly random (in the not-predetermined sense). What chaos theory does in the real world is to magnify the true uncertainty of the quantum world into macro-scale uncertainty. In a system such as when the ultimate position of a metal-tipped pendulum swinging over two strong magnets is determined by it's starting position in a 'fractal' manner, and for some regions, the initial position of the pendulum has to be known to literally infinite precision - but for quantum/heisenberg reasons, we know that's impossible. Hence the final position of the pendulum is indeed both entirely unpredictable (even in principle) and not predetermined (in the sense that quantum effects are not predetermined). The chaotic nature of that system magnifies quantum uncertainty to macro scales. So even something as 'classical' as a pendulum over two magnets is affected by quantum randomness - and that's enough to bust open predestination. However (as I said before) I don't think that opens things up to "free will" since we cannot influence either the macro-scale chaotic system that is our brain or the quantum randomness that drives that unpredictability. I suppose if you want to equate free will with some quantum-scale randomness, then you have your "get out clause" - but it's not very convincing. SteveBaker (talk) 14:45, 20 March 2009 (UTC)[reply]
Thanks. I completely agree with you. I guess we can summarise as "quantum effects generate true randomness at the microscopic level, and chaos theory says that those microscopic causes can have macroscopic effects". DJ Clayworth (talk) 15:18, 20 March 2009 (UTC)[reply]
i think that evry thing run with aperfect order ... random theories is a sily way to avoid looking for answers , evry action on this universe will affect the whole universe by the way under the same conditions.
the problem that we are trying to explain the whole universe while we're still ignorant about alot of the world basics,even in the most trustable theories in science we have to assume that the light travel with qunstant velocity , while its not, but this assumption could twist the theory so much in ahigher level , and thats why as the science keep going we try to come up with a more accurate theories .
when you try to build lets say a 1000 mile\ hour car you will need more accurate calculations than the ones you will use to build a 150 mile\hour car .
we always try to simplefy evry thing so we can predict it , and there were evry thing goes wrong . and when evry thing go very very complex for our minds we start to use this randomness theories . —Preceding unsigned comment added by Mjaafreh2008 (talk • contribs) 02:01, 20 March 2009 (UTC)[reply]
Well - you're in good company. Albert Einstein refused to believe it too - but sadly, the fundamental randomness of the subatomic world is all too real. If your computer has flash-memory in it - then it only works because of quantum randomness. This is more than just some maybe-true theory - we can do real engineering using it and produce real products that depend on it. SteveBaker (talk) 03:35, 20 March 2009 (UTC)[reply]
I apolgose for sounding arrogant, but most people here (except Tango) are missing a very important point because they are so used to the determinism of physics being the unviolable constant in natural science. Let's start at the beginning... the determinism of physics was discovered through the efforts of various scientists like Galileo and Newton who deciphered various physical laws that governed the behaviour of physical bodies. Determinism wasn't always the accepted (or intuitively correct) principle. The discovery of physical laws went up to make up the edifice of physics which was governed by fixed laws. These laws, until the discovery of quantum processses, meant that you could predict the behavious of any physical system accurately as long as you know the state of the system (position and velocity of particles) at a given point. Now here comes the important part... at some point people (like our OP) make the mistake of extend the determinism of PHYSICS to humans as if humans were nothing more than physical systems. The difference is that there is an entity called the will, which comes into the picture to decide how we will behave. This entity of the will lies outside the purview of Physics. I am not talking matphysical mumbo jumbo here. It is an important question in the study of the philosophy of mind - extending to the concepts of materialism/dualism/idealism. In short, the determinism of the physical world does absolutely nothing to undermine the existence of free will - and you don't need quantum indeterminism or chaos theory to account for that. The question of free will is fundamentally a philosophical one, not physical. --ReluctantPhilosopher (talk) 07:28, 20 March 2009 (UTC)[reply]
What was the arrogant part - that you claim humans are more than just "physical systems" with no evidence to back it up? To me all the evidence points to humans being organisms, with which our "will" helps us maintain homeostasis and ultimately reproduce. Although the physical system can act differently, i.e. in suicide. Depression is still a very complex disorder which isn't well understood and many brain regions are involved, so I can't say specifically what is wrong which would lead to a human to kill itself. --82.21.28.65 (talk) 11:11, 20 March 2009 (UTC)[reply]
"you claim humans are more than just 'physical systems' with no evidence to back it up" - well there is no evidence to the contrary either. You are basically arguing the case for materialism. Materialism states that everything is fundamentally physical, with "will", "conciousness" etc. just being words we throw about to account for our experiences. Well it's not a settled question - and the debate is very much alive on it. Dualism and Idealism are other alternatives. I personally believe in a sort of dual aspect theory --ReluctantPhilosopher (talk) 11:55, 20 March 2009 (UTC)[reply]
Well, you're the one positing an extra-physical "will", so you're the one obliged to do better than saying "there's no evidence to the contrary". --Sean14:11, 20 March 2009 (UTC)[reply]
Einstein only refused to believe in it until there was an overwhelming amount of evidence for it. Once that evidence was provided he accepted it, as any good scientist would. --Tango (talk) 12:39, 20 March 2009 (UTC)[reply]
I'm not sure that that is correct. My understanding is that Einstein never accepted quantum mechanic's indeterminism and tried until his death to find a deterministic model. A Quest For Knowledge (talk) 13:09, 20 March 2009 (UTC)[reply]
Well, yes, I guess you are right - he accepted most of QM, but not the Copenhagen interpretation of it. As I understand it, it was about 17 years after his death that experiments were performed that conclusively showed things like the EPR paradox should be resolved in favour of QM. I don't think he disagreed with anything that was firmly supported by experimental evidence that was available to him (although I could be wrong - I haven't studied the matter in any depth). The point I was trying to make (rather unsuccessfully, perhaps) was that arguments to authority along the lines of "Einstein didn't believe in QM, so neither do I" are seriously flawed since we have access to more experimental data now than Einstein did when he made those statements. --Tango (talk) 14:42, 20 March 2009 (UTC)[reply]
Unfortunately, my knowledge of physics only extends to one college physics class and whatever's on the Discovery and Science Channels, but apparently some people are still trying to come up with a deterministic model. [11]A Quest For Knowledge (talk) 15:18, 20 March 2009 (UTC)[reply]
There are always a few people on the fringes that disagree with everyone else. Without them we wouldn't have paradigm shifts, so they have an important role in the scientific community, but until other scientists start agreeing with them it's best for us non-scientists that don't understand the subject well enough to pass judgement on their theories to just assume the majority are right. --Tango (talk) 17:20, 20 March 2009 (UTC)[reply]
Carbon Fiber
What exactly is the tensile strength for carbon fiber? And how much does it cost? I can't find the information anywhere. I thought this might be a good place to ask. <(^_^)> Pokegeek42 (talk) 22:42, 19 March 2009 (UTC)[reply]
Our article gives a value of 5650MPa or 820,000 psi for the tensile strength, but note from this source "Overall, the strength of a carbon fiber depends on the type of precursor, the processing conditions, heat treatment temperature and the presence of flaws and defects"[12]. Mikenorton (talk) 23:01, 19 March 2009 (UTC)[reply]
Also, the tensile strength for carbon fiber will depend on the orientation of the fibers, as well as the matrix you use to bond the fibers. It is entirely possible for the tensile strength for a force in one direction to be 2x that in another direction. Also, the manufacturing process will introduce errors that can weaken the carbon fiber, so there is not really a simple answer to this question. As far as cost goes, I am not sure, but I believe a lot of the high costs associated with carbon fiber is not so much the cost of materials, but the cost of labor. It is time consuming to manufacture if you want quality stuff.65.167.146.130 (talk) 13:30, 20 March 2009 (UTC)[reply]
No - the drug residues are inside the hair - not on the outside where it could be washed off. I guess you could shave it all off...that would make it kinda difficult to test! But don't forget it would have to be ALL of the hair on your body....hmmm - I guess that also might make it obvious that you tried to hide your past drug use. SteveBaker (talk) 23:27, 19 March 2009 (UTC)[reply]
(EC with SteveBaker) Hey... My wife did her master's thesis research on drug testing in hair, so she is uniquely qualified to answer this. According to her, the drugs are bound in the structure of the hair itself, and any topical washing is going to have no effect on this. Even treatments like bleaching and the like will not remove it; it may reduce the concentration slightly, but there is no way to remove all traces of the drugs from your hair. According to her (who spent two years studying this exact thing, mind you) the only way to get rid of the drugs is to get rid of the hair. Good luck with that! --Jayron32.talk.contribs23:29, 19 March 2009 (UTC)[reply]
Wouldn't that only detect very recent drug use, though? The idea of testing hair is that it can detect drugs that were in the system when that hair was grown, which could have been some time ago. I think shaving your head would work as long as you haven't used drugs in a long enough time that the hair anywhere else on your body isn't long enough (and therefore old enough) to contain traces of them. --Tango (talk) 23:35, 19 March 2009 (UTC)[reply]
Indeed, detectable compounds only remain in the folicle for a short while. Folicle testing could, in theory, tell if you recently smoked a j... But hair testing can show that you smoked one last year... Or last month, or smoked most of last year and stopped six months ago. Its pretty neat stuff... --Jayron32.talk.contribs02:48, 20 March 2009 (UTC)[reply]
March 20
Supernova confusion, and the fate of nearby/bright stars
Hi. The article on Supernovae states that type Ia supernovae are the result of star-dwarf interactions, type Ib and Ic are the result of truly massive stars, possibly Wolf-Rayets, and that type II supernovae have a mass of at least 9 solar masses. However, this causes a contradiction. The article on the Chandrasekhar limit states that stars with masses greater than 1.4 solar masses will collapse into a neutron star rather than a white dwarf, therefore initiating a supernova. Or, is this defined by the mass of the star in the late phase of its life, when it has burned the hydrogen and helium and begins to swell, thereby losing some of its mass? I see that most stars visible in the night sky do have masses greater than 1.4 Sol. Why are there not more supernova explosions in our own galaxy, then? Is it possible for stars to gain significant mass during their lifetime, other than by ingesting material from a companion? The article on black holes does not mention this, but I read somewhere that a star having a mass over 6 Sol is a good indication it may collapse into a black hole (assuming that any core remnant is not destroyed). Also, when two medium-mass stars with similar masses in a very close binary system collide (due to gravity in the system shrinking their orbits, not a by-chance collision), is the result a supernova or a hypernova? The article on supernovae does not mention this category, and apparently hypernovae refer only to hypergiants collapsing.
If the limit for a star to end as a supernova is indeed 1.4 Sol, then looking at the top ten brightest stars in the sky, it looks like that Arcturus and Vega will explode as supernovae; Sirius and Procyon will also explode as supernovae, but interactions with their companion dwarf star could initiate a type Ia instead; Canopus and Achenar will explode as supernovae, and are just massive enough to perhaps end as black holes, Rigel and Betelguese will be especially energetic supernovae resulting in black holes; Rigil Kentarus will have one star swell to red giant first, probably star A, then shed its outer layers, and if the explosion doesn't significantly disrupt the second star, then possibly its remaining material will migrate towards the remnant of star A; Capella appears to be a binary system of two stars massive enough to generate supernovae, perhaps the explosion of one will disrupt the other, or else we could have stellar matter being drawn towards a neutron star. Most of these stars will probably be well away from Earth, though, by the time the explosion occurs, because a positive radial velocity would cause the star to be farther away, and a negative one probably means the star will have long receded by the time the explosion occurs. Or, is there something I'm missing here? Would this mean that supernova explosions are likely to be common near Earth, and would they significantly affect our atmosphere?
Also, what exactly are the evolutionary phases of higher-mass stars (those heavier than 1.4 Sol, specificly)? Does a blue giant evolve to a red supergiant, does a blue supergiant evolve any farther before exploding, what about white and yellowish-white stars in this category, are they still the young versions of red giants or red supergiants? Also, in the case of supergiant-black hole interactions, such as with Cygnus X1, what is expected to occur when the supergiant itself goes through the end of its life cycle? Thanks. ~AH1(TCU)01:29, 20 March 2009 (UTC)[reply]
Wow, so many questions... I won't tackle all of them. The gist of most of what you are asking seem to boil down to "what happens to stars that are heavier than chadrasekar's limit but are lighter than 9 solar masses? Some of them will end their lifes as Planetary nebula. This page has a nice explanation. Dauto (talk) 03:18, 20 March 2009 (UTC)[reply]
My point was that after shedding the outer layers on a planetary nebula the 5 sol star isn't a 5 sol star no more. So that's the end of the 5 sol star. Dauto (talk) 13:38, 20 March 2009 (UTC)[reply]
Hi. OK, so it appears middle-weight stars usually end up with a much lower mass. What happens, however, with binary systems like Sirius and Procyon, does the white dwarf absorb the extra material and end up as a type Ia supernova? Also, is it possible to predict whether a star such as this will lose most of its mass or not? Thanks. ~AH1(TCU)17:14, 20 March 2009 (UTC)[reply]
hair tests again
thanks for the aswers.
but i'm confused...if ur hair takes in drugs....does that mean almost any chemical put in our bodys go in the hair? or is God just getting back at stoners? —Preceding unsigned comment added by 76.14.124.175 (talk) 02:03, 20 March 2009 (UTC)[reply]
Asking my wife again. It's not that everything you take in ends up in your hair, but most drugs have chemically very similar chemical compositions, and those compounds do tend to accumulate in the hair. After all, the basic idea of drugs is that they mimic chemicals in your brain, and those chemicals also tend to accumulate in certain places like hair and fingernails. It isn't that ONLY drugs do, its that drugs are one of the things that do accumulate there. There are many other things that do, like heavy metals and arsenic, and hair tests can be used to show that a person has been poisoned over a period of time. The deal with hair is not that it magically absorbs drugs; its that it lasts a LONG time, so it carries a record of things you have taken in over a long time. And, ethnicity does effect hair type; your ethnicity can be positively identified by microscopic analysis of your hair... however no person or ethnicity is immune from these hair tests. Again, your only option is to shave your head; however if you shave it after being told that you need to give a hair sample for a drug test, then they will likely know exactly why you did so. Your options are a) don't do drugs or b) don't apply for jobs where it matters... --Jayron32.talk.contribs02:46, 20 March 2009 (UTC)[reply]
I don't believe shaving your head will do the trick. We don't have hair only in our head. There are also other ways of testing for drugs - read drug test for more, but they don't have a long detection period like hair test.--80.58.205.37 (talk) 12:54, 20 March 2009 (UTC)[reply]
Are humans the fastest long distance runners?
When it comes to the fastest on land, everyone bows down to the sprint of the cheetah. But beyond the sprint, what is the fastest land animal over a substantial distance, let's say 50 miles or so? I've recently heard an assertion that we, as a species, were very successful in our infancy because we evolved to be the best at tracking herds over very long distances. Sappysap (talk) 02:37, 20 March 2009 (UTC)[reply]
I've heard that said, many times. It may be true...but I don't think so. Marathon runners can do 26 miles without a break. However, in the Man versus Horse Marathon - the race was won by horses in the first seven years although a human did win on the eighth event - but on a bicycle (which, IMHO, is cheating). The race was run for 25 years before the first human won on foot. In 28 years of running the event, only two humans have ever won on foot. For some reason that's only a 22 mile race, but it's cross-country - which may give the horse an unfair advantage. But then consider that they horses are HEAVILY handicapped by having to run with a human rider on their backs! If the runners had to carry a 40lb backpack - I think it would slow them down too!
So it's abundantly clear that 22 miles isn't enough to give the human a winning advantage. I had a neighbour in England who was a big time long-distance runner. He did the London-to-Brighton foot race (which I think is 50 miles or so) - also several double-marathons (52 miles) and the South-Downs-Way run (I believe 70 miles) and the Isle-of-Wight race which is also some crazy long distance. But I don't think an average human can do that - even with training.
Yes, true. But may be the 'Man versus Horse Marathon' isn't the best way to test the hypothesis. Horses, after all, are pretty good long distance runners themselves. May be we would do better against animals more adept of short bursts of very fast sprints like impalas? Dauto (talk) 03:54, 20 March 2009 (UTC)[reply]
But here is my hypothesis in a nutshell: We know that most people (my wife, for example) can more or less run 26 miles - with a bit of training (she's never run a race over any distance in her entire life - she trained over two months - and finished the London Marathon in a hair over 5 hours - although she did walk some of the way). It's not unreasonable to suppose that pre-soft-living-modern-civilisation-humans could all run at least 26 miles if they had to. But we also know from the Man-vs-Horse thing that AT LEAST the one species we've seriously tried this against can beat us easily over 22 miles WITH A HUGE LOAD ON THEIR BACKS. So I'm betting that horses without riders would have no problem whatever in whipping our asses out to at least a few miles beyond the regular marathon distance. However, we have these ultramarathon loonies who run 50 mile races. It's perfectly possible that the horse gives up at about 30 miles...and that SOME humans can make it out to 50 miles. But if we're taking about maybe 1000 people in the world who run ultramarathons - that's the top 0.00001% of humans. I'm pretty sure we couldn't all do that - even with training. And what if we picked the very best long-distance horse out of all the horses in the world - and trained the heck out of it. Gave it really nice Nike running horseshoes and a digital heart-rate monitor with integrated pace timer - no rider, no saddle - and made sure it had specially formulated 'rehydration' stations every few miles...wouldn't the best horse manage equal amounts of improvement over the general population of horses? I don't think there is any evidence whatever that a 'typical' human could out-run a 'typical' horse over any significant distance...and I don't believe that the top 0.0001% of humans with the best training and support facilities could beat the top 0.0001% of horses if they were given fair training and support (and no riders!). And that's just horses. What about all of the other long-legged runners of the world? I think this one is busted...unless there is some solid evidence to the contrary. SteveBaker (talk) 14:22, 20 March 2009 (UTC)[reply]
Wait, that's not a fair comparison at all! Horses have been bred for centuries for speed, endurance, carrying capacity, etc. How would a horse's pre-domestication ancestors fair in a human-vs-Equus ferus marathon? APL (talk) 01:09, 21 March 2009 (UTC)[reply]
How is that fair either thought? Prehistoric humans were probably quite fit but I doubt they compared to modern professional marathon runners at running such long distances. Nil Einne (talk) 14:05, 22 March 2009 (UTC)[reply]
Let's play devil's advocate for a bit... Okay, so an average horse could beat an average human in a single race of 50 miles. How soon until it can go another 50? I imagine it would take a lot longer to refuel a horse than a human; in fact, if the human slowed to a walk here and there, it could refuel on the run to some degree, or at least take in some water. Quadrupeds can't do that. The horse is going to need enough energy to haul its 1,000 lb carcass across the plain, while the human only needs to haul its ~150 lb carcass, and gets to take in higher calorie foods to boot (including, er, horse, but that's a bit rude to your opponent...). Sooner or later the issue of fuel quality and fuel consumption are going to overwhelm any short-term equine superiority. Maybe. Matt Deres (talk) 20:14, 20 March 2009 (UTC)[reply]
Interesting point - I hadn't thought about it that way. However, horses are capable of eating grass, which is generally more readily available in large quantities than food suitable for humans. --Tango (talk) 20:34, 20 March 2009 (UTC)[reply]
See Persistence hunting. Wolves quite probably could beat humans as they also do something similar, I don't know. It would only need a good fit person to run down a horse without a rider though, they wouldn't need to be Olympic standard or anything like that. And by the way I've run longer than that 50 miles of those 'ultramarathon loonies' ;-) Dmcq (talk) 22:40, 20 March 2009 (UTC)[reply]
Why do you say that? As SB has mentioned given the conditions the horse with a rider is subject to, it seems resonable a horse without a rider would be capable of being faster. The question is would it ever actually run that fast if there isn't a rider edging it on? Well it's difficult to say IMHO. As I've mentioned below, in general we can expect most animals wouldn't. But if you are chasing a horse as a prey and the horse realises you are a predator it seems to me easily possible the horse will actually run that fast Nil Einne (talk) 14:33, 22 March 2009 (UTC)[reply]
I just had a good read of the Nature article referenced at the end of the wiki article on the evolution of endurance running in humans and it says some dogs and horses that have been bred for endurance would probably beat humans. The wolves article says they normally give up chasing after a fairly short distance but one was observed hunting a moose for 35km. Another animal that possibly would beat humans is the kangaroo. Dmcq (talk) 17:46, 21 March 2009 (UTC)[reply]
The refueling thing is an interesting point. It's worth remembering many (not all obviously) marathons don't involved the runners bringing their own water. Nil Einne (talk) 14:07, 22 March 2009 (UTC)[reply]
IMHO one issue we're not addressing is the difference between what can be done, and what is done. Personally, it wouldn't surprise me if a number of animals can beat humans in general. However many of them are never going to do it in practice. Similarly while humans may have evolved endurance for long hunts, what sort of distance are we talking about here? Did humans really chase animals by running after them non stop for 50 miles? Nil Einne (talk) 14:11, 22 March 2009 (UTC)[reply]
Without having read the article that Sappysap is referring to, I wonder if it's solely referring to our endurance or it may also refer to our intelligence etc. I presume one advantage humans have is that they have endurance and also intelligence. Let's say you are chasing something. Perhaps it's about the same speed as you so you don't really catch up to it and it doesn't escape. Eventually you tire and slow down (or perhaps you could go on but decide the current run is pointless). It 'escapes' and then slows down itself. Trouble for it is you may rest and 'refuel' and then go on. You can see it's tracks so you can easily still go after it. It doesn't know this so it's not necessarily running away from you any more. Eventually you may get close and it sees you and runs away again. Perhaps you repeat the same thing. It's easily possible you will ultimately win because you are chasing it in a direct line and wearing it down successful. It's not necessarily the case you have more endurance then it, you have good endurance sure but you are also smarter. Nil Einne (talk) 14:33, 22 March 2009 (UTC)[reply]
Plenty of animals are far better trackers than humans. Humans may have an advantage in a race to a pre-determined finish line because we can pace ourselves. I'm not sure any other animal would understand the concept of a long distance race well enough to do that. In a chase, though, pacing yourself doesn't really help unless you know how fast you and your opponent can run and for how long at various speeds and can work out a strategy to win, which would be rather difficult (an maybe impossible, depending on the respective abilities of the predator and prey). --Tango (talk) 14:40, 22 March 2009 (UTC)[reply]
You'd have to watch the episode in David Attenborough's series 'The Life of Mammals' where a Bushman runs a kudu to death to really appreciate what can be done. They typically have to run 25 or 35 kilometers which is nothing to a trained long distance runner. Dmcq (talk) 00:06, 23 March 2009 (UTC)[reply]
What is your point? So humans are better long distance runners than kudu, that doesn't answer the question. We knew humans weren't the worst, we're asking if they're the best. --Tango (talk) 00:12, 23 March 2009 (UTC)[reply]
You seemed to think it required special pacing. It doesn't. To win against other humans does. As to the best long distance runner I don't know but my best guess would be the kangaroo, I'd be surprised if humans actually are the best but they're very good rather than not the worst. I haven't a citation but I believe people in America in the past have run down wild horses rather than doing the sensible thing and creeping up and lassoing them. Dmcq (talk) 14:49, 23 March 2009 (UTC)[reply]
When the sun becomes a red giant...
About how long will it take for it to expand from its current size to red giant size (following the collapse of its core once the hydrogen there is used up)? 69.224.37.48 (talk) 03:09, 20 March 2009 (UTC)[reply]
its the biggest question ever ... what's the beginning , what's the source of evry thing .. if i said god is the source, atheistes will be angry.but if i said it's avery powerfull elian had created the earth ... i think they will buy that.
i just need to know whats wrong with god theory ... it might be right . but i think that humans dont like the idea of being a lower cretures ... we are so pride to be god slaves,we need so much to belive that there's no destiny ,so we can make our own.
human evolved from monky...monky evolved from (whay ever)...all the way to the creation of the universe ... from where did the universe came from ... from where that gas came from ... what is the first thing ... what is ground zero.
and if there is no god , and all this religion thing is just acrap,then i think the best thing that happened to the earth is hetler...we must let the smartest,the strongest , the healthiest ones to survive .who cares about moral standards ,we invinte these standards,and we can change them ,i think it's inmorale to leave the weak alife so they can multiply and reduce the chances of our survive,we should eliminate them.
and why do we evolve to have this huge power of thinking ... were we to needy to find answers for the question we had before we have the mind to ask.whats the need driven us to evolve to have this huge brain ... food ..???
There are two (implied) questions you are asking, even if you don't realize it. They have different answers. Question 1 is "What is the process by which the universe was created" or "what went on when the universe came into being". Its a procedural question. The answer, as far as we can tell, is that some form of the Big Bang brought it about, somewhere in the neighborhood of 13-14 billion years ago. Now, while this satisfactorily answers your first implied question, it does not answer your second which is "What is the cause of the Universe coming into being" or "What is the purpose for which the universe was created". The answers to THOSE questions are ultimately unanswerable via direct observation or by inferences from those direct observation. Assigning meaning and purpose to creation isn't really the realm of observational study, so one must derive their own personal answer to the question. Did God make it so? Is it all random? Any answer you arrive at must be arrived at via faith, even if your answer is "The universe has no purpose at all". You may be interested in looking into the field of Cosmogony which discusses the philosophical (as opposed to the procedural) questions of the creation of the universe. --Jayron32.talk.contribs04:28, 20 March 2009 (UTC)[reply]
Let me point out one thing you said that reveals you haven't thought about that long enough.
You said "i just need to know whats wrong with god theory ... it might be right . but i think that humans dont like the idea of being a lower cretures ..." If that was true, most people wouldn't believe in God. We know that that's not the case.
Now, if we skip all the senselessness about eliminating week people (not a very moral thing to say), we get to the only thing in your rant that actually sounds like a science question:
You asked "why do we evolve to have this huge power of thinking?"
Oh, someone who concludes that if there is no God, Hitler is awesome because without God there's no morality! Why, sir, you have unintentionally created an argument for belief in God! What an amazing coincidence! -- Captain Disdain (talk) 10:53, 20 March 2009 (UTC)[reply]
As far as I understand it, evolution doesn't say that humans evolved from monkeys. Instead, it says that humans and monkeys evolved from a common ancestor. This common ancestor no longer exists (i.e. it is extinct). 12:59, 20 March 2009 (UTC) —Preceding unsigned comment added by A Quest For Knowledge (talk • contribs)
Well, yes, that's true. It's accurate to say we evolved from apes, but monkeys are a separate class of primate - it wouldn't be accurate to describe the most recent common ancestor of modern monkeys and humans as a monkey. (The most recent common ancestor of humans and non-human apes was an ape, though.) --Tango (talk) 13:12, 20 March 2009 (UTC)[reply]
Here we go again...
its the biggest question ever - maybe - but I think I have bigger ones. Abiogenesis is one. Is there intelligent life throughout the universe is another. Are there parallel universes is a third. But this is right up there.
... what's the beginning , what's the source of evry thing - that's an easy one - the Big Bang. We're really very sure about that now. We know pretty much exactly what happened from about the first millisecond of existance. We still need to fill in some details about dark-matter and dark-energy - but we're definitely getting there.
.. if i said god is the source, atheistes will be angry. - No, not angry. Saddened perhaps. Exhausted maybe.
but if i said it's avery powerfull elian had created the earth ... i think they will buy that. - No, we wouldn't. That's really not what the science says and it wouldn't explain how the moon was formed from a collision between early earth and another Mars-sized planet. We don't need 'aliens with godlike powers' as a substitute for 'god' - we have strong evidence for a relatively mundane explanation that centers around stellar remnants, gravitation, that kind of thing.
i just need to know whats wrong with god theory ... - it's "Unfalsifiable". That means that there is no conceivable experiment that could be done to either prove or disprove the theory. The "god theory" is (scientifically) no more and no less probable or provable or credible than that I made the earth and have been keeping quiet about it all these years. There are literally an infinite number of unprovable ("wild-assed") claims you could make - they all have equal status with the "god theory" - and we can't go around believing in an infinite number of random things. On the other hand - we have an exceedingly good 'conventional' theory that works perfectly well without hypothesising supernatural causes. God simply isn't necessary for our explanation of the universe. You might like to read about Occam's Razor.
it might be right. - well, it might but so might be the theory that the Invisible Pink Unicorn (mhhbb) did it...or that roaming gangs of green furry fish did it. I can keep coming up with these stupid suggestions from now until doomesday - they are all just as valid as the "god theory" - there is the same amount of evidence that they are true (ie NONE) and just as easy to prove or disprove (ie IMPOSSIBLE). So why should we give the "god theory" a moment's more attention than the IPU (Invisible Pink Unicorn - mhhbb) theory - at least the incomprehensible but undeniable existence of pineapple and ham pizza provides at least a shade of evidence for the IPU? (I'm kidding - OK?)
but i think that humans dont like the idea of being a lower cretures ... - that's true. When I was a kid - the text books said "Humans are superior to the animals because we have language and use tools." - but then we discovered that bees have a language (involving dancing and wiggling their butts) - and lots of animals use tools (watch a starling breaking open a snail shell by hitting it with a pebble). So the next generation of textbooks said "Humans are unique because we MAKE and use tools."...but then we found that chimpanzees strip the leaves off of thin branches to make tools for getting ants out of termite mounds...and there is a fish that cuts and shapes leaves to make a disguise that it holds over it's body so that birds can't see it swimming by. We are clearly at the 'top of the heap' - but reality keeps reminding us that we're really not that much more superior to the "lower" creatures.
we are so pride to be god slaves,we need so much to belive that there's no destiny ,so we can make our own. - I certainly don't want to be a "god slave". I couldn't imagine what it would be like to believe in all that stuff. To have to continually bow down to an infinitely superior being? Urgh! We have not made up all this stuff we've found out about the universes. We've investigated what the universe has to tell us. We know the Big Bang is true because (in a sense) we sent up a spaceship to take a photo of it! The cosmic microwave background is the clearest proof that the Big Bang really happened. If you take the time to understand the science behind it - you'll be convinced too!
human evolved from monky...monky evolved from (whay ever)...all the way to the creation of the universe ... from where did the universe came from ... from where that gas came from ... what is the first thing ... what is ground zero. - Ground Zero is the Big Bang. We're pretty solidly clear on everything that happened from then to now. What we don't know - and what (if you must) you could attribute to a "God" is what actually caused the Big Bang in the first picosecond of the life of the universe. I don't think we need a supernatural explanation for that - but if you must, you could imagine a god who decides to make the universe and after about a picosecond - steps back and lets it all roll out without touching anything after that. This makes a sort of sense I suppose. It's a "God of the gaps" argument. Wherever we don't yet have a scientific explanation - you can stick God in there. Sadly, those gaps are getting smaller every year. Science is making huge leaps in figuring this stuff out - and every time we plug a hole, there is less need for a god to make a workable explanation. Give it ten years and the role of god will have shrunk from a picosecond to an attosecond. But this raises a bigger question for me. You aren't prepared to accept that the "Big Bang" came from nowhere (despite good evidence pointing that way) - yet you are entirely happy to accept that God "just is" - nobody asks "what is the origin of god?"...but if we were (as scientists) to accept the god-theory, that would have to be the first and biggest new question. "Where did God come from?" When I ask that question, I get some vague hand-wavey thing about him always having been there - or "He's outside of time and space". But when I say that time actually started with the big bang - and that it's meaningless to ask what came "before" - you get all huffy about it and start demanding why I don't have an explanation. Your theory is certainly no better than mine - and Occam's razor says it's a lot worse because it involves a whole extra step that my explanation doesn't need.
and if there is no god , and all this religion thing is just acrap,then i think the best thing that happened to the earth is hetler...we must let the smartest,the strongest , the healthiest ones to survive - but that's not true. Hitler's actions were not acceptable to the majority of humanity - or even to his own people when they finally realised what was happening. So Hitler was attacked from all sides - Europe, Russia, the US...and driven to extinction. He died because the majority of humans could not accept his behavior. That's because we've evolved a mental capacity to reflect the feelings of others - that capacity means that we can put ourselves into the positions of the poor people in those death camps - and we become outraged and belligerent - and we fix the problem. That's an evolutionary response to a failed genotype. Religion had very little to do with that. Plenty of atheists fought against Germany.
who cares about moral standards ,we invinte these standards,and we can change them - some we can - others are so inbred into our genetics that we can't. You can't just decide to do something that's morally repugnant to you. I could no more kill my son than I could kill myself. That's not a matter of logic - it's a matter of what my brain chemistry has made me be. We are like we are because of the genetics of being a "pack animal".
i think it's inmorale to leave the weak alife so they can multiply and reduce the chances of our survive,we should eliminate them. - you say that, but I doubt very much that you'd be able to carry it through. I have no god commanding me not to do that - and I certainly give money to help the needy - I volunteer to help out underprivilaged kids - I donate my time free to answer people's questions here on the Wikipedia reference desks. Without a god - your claim is that I should have no reason to do those things...yet I do! Gladly. For the betterment of mankind - for the survival of the species - for the survival of my genes into future generations. This is a moral standpoint for sure...but one that does not in any way rely on religion to prop it up. I actually agree with most of the more important of the Ten Commandments (although one or two of them are a tad nutty). "Thou shalt not kill" works very well for me! In fact, I'd prefer to avoid the weasel-words added to that that say "oh...unless it's a war or something...or maybe murderers could have the death penalty...and in Texas it's OK to shoot burgulars". No - for me, "Thou Shalt Not Kill" actually means what that bloody stupid book says it does. Not because there is some old white guy up in the clouds somewhere telling me to...it's because my brain tells me that killing (in general) is not a good thing. I have moral principles...pretty strong ones actually. They just don't derive from religion.
and why do we evolve to have this huge power of thinking ... - it helped early humans to be smart. The smartest ones didn't get eaten by the sabre-toothed tigers - so they had more kids - who inherited their parent's smarts - and gradually, via the relentless force of evolution we evolved to what we are now. It's not in any way a mystery.
were we to needy to find answers for the question we had before we have the mind to ask.whats the need driven us to evolve to have this huge brain ... food ..??? - Sex, actually. But food also.
will .. after all evry thing could be true , just leave the door open. - No. It's ridiculous. I don't have the time to go around believing in green furry fish that MIGHT have created the universe - I don't have time to believe that there MIGHT be a teapot orbiting Mars right now. I don't have time for any of the hundred or so wildly different supernatural claims for a "god" or "gods" either. It's unnecessary and (frankly) ridiculous.
Yes, that's right, although we have little or no idea what was going on just before that expansion started (or even immeadiately after it - there is a fraction of a second at the beginning during which our physics breaks down). --Tango (talk) 17:46, 20 March 2009 (UTC)[reply]
'mhhbb' stands, I believe, for 'may Her Hooves be blessed' and is a standard phrase when referring to Her. 'bbhhh' ('blessed be Her holy Hooves) and 'mhhnbs' ('may Her Hooves never be shod') are also in use. 'mtasnro' is a new coining standing for 'may Their ant supply never run out' and is a phrase used to propitiate the pink aardvarks who run the universe. Algebraist19:02, 20 March 2009 (UTC)[reply]
Thanks much for the info, faithfully recorded in my notebook! After Steve's analysis on the chances of being killed in a meteorite strike a while ago, I'm taking no chances on suddenly being called to the "undiscovr'd country from whose bourn no traveller returns". 'Scuse me now, I have to run out and find a goat, a virgin, a 100-foot tall flammable man-like structure and some chicken bones before nightfall. Oh yes, a box of ants too. :)
And to get even more sidetrack-ey, what's the name for when you find only one instance of a Google search term? Of course, when you report it, it then shows up twice. You were oh-so-close there! :) Franamax (talk) 22:43, 20 March 2009 (UTC)[reply]
I get the feeling a lot more evolving of this power of thinking is needed. Or perhaps by then we'll all have evolved so the muslim faith or whatever is bred into our genes. Then nobody will have to ask - we'll all 'know' without any evidence just like the OP. Wouldn't that be a grand fate for our descendants. Dmcq (talk) 15:30, 23 March 2009 (UTC)[reply]
the iron content in steel wool lab queries
for an important lab we're doing titled "percentage of iron in steel wool", a sample of steel wool is placed in excess dilute sulfuric acid, and this supposedly converts the iron present in the steel wool into Fe2+ ions......then, the Fe2+ ions in the solution are titrated against a standard permanganate solution, and thus are further oxidised to Fe3+ ions, while the permanganate ions are reduced to Mn2+ ions..
do you have any idea of the kind of questions that are likely to be asked of me in this lab? also, i'm assuming my teacher will give a 'manufacturer's value of the % Fe'. do you know the equation to figure out the % difference between your value and the manufacturer's claim?
Percent difference? That's a pretty technical article, but the essence is in the "Percent error" formula and the intro: it's a ratio of the difference between the values to the values themselves. You might take one value as "correct" and thus compare to it, or you might just take them both as "someone's data" and consider the average of them to be the value to compare. I would ask a student to write the net ionic equations for the redox reactions involved in this experiment. DMacks (talk) 04:56, 20 March 2009 (UTC)[reply]
You're likely to do stoichiometry calculations somewhere to figure out the mass of iron in your original sample. This can be done any number of ways, but since Fe3+ ions are colored, you could use a spectrophotometer, a series of standardized Fe+3 solutions, and Beer's law to calculate the concentration of Fe+3 ions in your unknown solution. Then, knowing that concentration and volume, you can find moles of Fe3+, which should ALL have come from the steel. You could also do the same via titration with a standardized KMnO4 solution; if you know the volume and concentration of the KMnO4, and have a balanced chemical reaction for the Fe+2/Fe+3//Mn+7/Mn+2 redox reaction, you can also quantitatively find the moles of iron in your unknown, and then its the same calculation as above. --Jayron32.talk.contribs05:03, 20 March 2009 (UTC)[reply]
potential energy
I was watching TV where i saw a man working in a high way project , this man was trying to crack a big rock , he kept hitting the rock with a hummer until and suddenly it just split into half , i asked about it and get some opinions like a potential energy is being stored in the mass until its enough to crack the mass,
but i think that the hummer is producing a hairy cracks at aspecified plan until its reach that critical edge where it to weak to resist that hit energy , so it jut crack down,what did you think....? —Preceding unsigned comment added by Mjaafreh2008 (talk • contribs) 10:24, 20 March 2009 (UTC)[reply]
The rock is certainly not storing significant energy from the hammer blows. It's much more likely that each blow (or even only some of the blows) create and propagate cracks and fissures, gradually weakening the rock. At one point the rock is weak enough that the last blow splits it. --Stephan Schulz (talk)11:12, 20 March 2009 (UTC)[reply]
As a professional rock splitter, I concur with that. When trying to break up a rock down to a size that you can take back as a specimen you generally concentrate your hammering on any obvious existing weakness such as a crack or a weathered zone. Normally you can see, feel (from the change in the response of the hammer handle) or hear (a change in the sound of the blow) when you've started to propagate a crack just before it finally splits. Mikenorton (talk) 11:24, 20 March 2009 (UTC)[reply]
You could argue that a rock with cracks in it has higher energy that one that doesn't (in the same way that two separate atoms have higher energy than when they are bonded together), but there is no way easy way to get that energy back so I'm not sure I'd call it "potential energy". --Tango (talk) 12:17, 20 March 2009 (UTC)[reply]
I'd bet that you're actually releasing energy in the rock by breaking bonds - but the biggest part of what your hammer blows are doing ends up as heat or sound energy (which in turn is going to be heat energy pretty soon). When you hit the rock - you are causing it to vibrate or accelerate (briefly) - and that's getting turned into heat by friction. So to the extent that the rock gets a bit warmer (and most certainly the hammer does - you can feel it!) you are storing energy in the rock - but not usefully. SteveBaker (talk) 13:14, 20 March 2009 (UTC)[reply]
During the recent gasoline price spikes, I imagine quite a few people "kept hitting a rock with their Hummer until suddenly it just split in half". I'm not sure if the junkyard would take half a Hummer, though. :-) StuRat (talk) 04:13, 22 March 2009 (UTC)[reply]
Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. SteveBaker (talk) 13:08, 20 March 2009 (UTC)[reply]
Transcription (genetics), Translation (genetics) look promising and weren't that hard to find. (Click on words in blue in a text on wikipedia and it will get you to the relevant page.) If the assigned textbook for your class doesn't give you good enough answers it might be useful to check if you have a well stocked library in the area. 76.97.245.5 (talk) 14:32, 20 March 2009 (UTC)[reply]
Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. SteveBaker (talk) 13:08, 20 March 2009 (UTC)[reply]
Yes, wikipedia knows. Here's how you can find out what: copy your word into the white box underneath where it says "search" in the left hand sidebar near the top of this page. Then click on "search". If you can't find a relevant page or have trouble understanding some of the content, please feel free to come back with a specific question. 76.97.245.5 (talk) 14:23, 20 March 2009 (UTC)[reply]
Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. SteveBaker (talk) 13:09, 20 March 2009 (UTC)[reply]
Yes, wikipedia can help. Here's how: copy your word into the white box underneath where it says "search" in the left hand sidebar near the top of this page. Then click on "search". If you can't find a relevant page or have trouble understanding some of the content, please feel free to come back with a specific question. 76.97.245.5 (talk) 14:19, 20 March 2009 (UTC)[reply]
If you put solar panels on windmills, could they help increase the energy given to the town or city or whatever the windmill's powering? What would you connect the solar panels to? <(^_^)> Pokegeek42 (talk) 17:38, 20 March 2009 (UTC)[reply]
I think putting the panels on the ground would be the best way to use the same space for solar and wind power. The alternative is putting them on top of the turbines (thus avoiding shadows being cast on them), but I suspect that would mess with the aerodynamics of the turbines and make them less efficient (whereas the shadows should be a mini\mal concern - turbines are pretty thin). --Tango (talk) 17:44, 20 March 2009 (UTC)[reply]
In terms of an individual windmill, its probably not all that efficient, but in terms of a national energy policy; diversifying one's energy sources is a sound idea. Generally, solar power is most productive at times and places quite different from the times and places where wind power is productive. Thus, they tend to complement each other as a source of power, but mostly so on a national rather than individual scale. In general, one windmill or a single solar panel running a single house, or even one of each, is a fantastically wasteful and inefficient way to do things. It would be far more efficient use of resources to provide power via Wind farms and Photovoltaic power stations. --Jayron32.talk.contribs17:54, 20 March 2009 (UTC)[reply]
What an impressive generalisation, but it just squeaks through as accurate but very misleading. In general a small number of solar panels in a house is a pretty efficient way to provide thermal water heating as a top up to other energy sources. Solar for the summer and a wood chip boiler in winter is fine for all year domestic heating. Plenty of people use wind and wood for heating too (but not city ants). Local solar panels are also very efficient to provide local summer heating for things like domestic swimming pools. Only if you convert solar or wood to electricity (at massive inefficiency) does it look very uneconomic at home and equally it looks uneconomic for most climates as Photovoltaic power stations. The trade off between economic of scale and transport cost and loss depends on many things and is not obviously one way or another. --BozMotalk18:37, 20 March 2009 (UTC)[reply]
When you consider transmission losses, local generation starts to look much better. But one windmill, even a utility scale one does not provide much area for the very inefficient photovoltaic power panels. You might get enough panel on the nacelle to get power one home. Rmhermen (talk) 19:25, 20 March 2009 (UTC)[reply]
However, covering the ground at a wind farm with solar panels might work quite well - wind farms are generally quite spread out and the area is often not used for anything else, as far as I know. --Tango (talk) 19:49, 20 March 2009 (UTC)[reply]
The windmill farms I've seen in the desert are not used for much, but the ones I've seen in the plains are used for cattle. Replacing their grazing land with solar panels will mean that the cattle need to graze elsewhere. Also, windmills require a lot of maintenance. It will be hard to work on one if you have to move a lot of solar panels out of the way first. -- kainaw™20:46, 20 March 2009 (UTC)[reply]
In Denmark, on-land wind turbines are quite commonly located on rural land and farming happens right up to the footprint of the turbine foundation itself which I believe is between 12 and 20 feet square. (And obviously the pathway needed to bring the maintenance equipment in counts as footprint too, but farmers need laneways for tractors anyway).
More desolate land, esp. deserts are good candidates for solar and mountains for wind - but yes, transmission losses, construction expense and bio-effects for the transmission lines come into play. There is a lot to be said for generation near to consumption, not least of which is grid stablization. If clouds pass over a remote solar plant or the wind calms at a wind-farm, everything in between supply and demand will see voltage effects, possibly quite severe. Franamax (talk) 22:54, 20 March 2009 (UTC)[reply]
The problem is that this idea is solving a non-problem. The problem with solar panels isn't in finding land to put them on. In all the places with the largest amount of sunshine, land is cheap. Deserts and prairie is easy to get for a couple of hundred bucks an acre. Compared to the cost of an acre of solar panels, the cost of the land is quite utterly negligable. So there is no need to make special considerations for putting them near windmills. To the contrary - you place windmills where the wind is good - you place solar panels where the sun is good - going out of your way to put one in the same place as the other is unlikely to be optimal. SteveBaker (talk) 23:35, 20 March 2009 (UTC)[reply]
The solar panels on windmills idea would be more of a benefit to home windmills, where space might be limited and trees and the house may cause shadows to fall on panels placed on the ground. If the windmill is on a tall mast, solar panels near the top would get more sunlight (the additional weight and wind-load might require a stronger mast, though). They could also be placed on the blades. In this case, the electricity could be transmitted from the moving blades to the rotating mast via brushes or some other method. StuRat (talk) 04:06, 22 March 2009 (UTC)[reply]
But that's a dumb idea...the windmill has to face into the wind - and the solar panels have to face towards the sun. Since there is little correlation between the two - you'd expect that either your windmill or your solar panels would be pointing the wrong way at least half of the time! Again, the limiting factor with solar panels isn't available area. Almost all houses have FAR more available roof area than the owner can afford to populate with panels. Going to all that grief to put a handful of solar cells onto the blades of the windmill (making them heavier - and therefore harder to get spinning in a light wind - requiring brushes to extract the power - which will inevitably add to the frictional forces - worse still - you are incurring all of those penalties during the night when the solar panels aren't paying for those additional costs!)...and all for what? About another three square feet of panels that's hardly ever pointing optimally? When did you last see a roof so packed with solar panels that another 3 square feet of them would be so urgently needed?! This is a STUPID idea....period. SteveBaker (talk) 19:39, 22 March 2009 (UTC)[reply]
Then there's the problem that the house roof may be in shade in areas with tall trees (like my house), so not at all suitable for solar panels. Also, there may be a minimum amount of electricity required for a house, and any beyond that may be wasted (if there's no way to sell it back to the power companies in that location). In such a case, pointing the blades either at the wind or Sun may be enough. When there's no sunlight, point it into the wind. When there's no wind, point it into the sunlight. When there's neither, you're out of luck. StuRat (talk) 03:43, 23 March 2009 (UTC)[reply]
You've still greatly added to the complexity of a device that already is unlikely to pay for itself. If your solar panels need to be up on a pole, it'd probably be better to put them on their own pole.
You probably could think up some contrived hypothetical situation where a solar windmill would make sense, but you'd really just be searching for a problem to your solution. APL (talk) 12:52, 23 March 2009 (UTC)[reply]
Russell Watson Brian Tumor
Hi
Do you know the name of the surgeon who performed Russell Watson's brain tumor operation at the Alexadra Hospital in Cheadle (Greater Manchester) in 2007? Many thanksCarlchester (talk) 18:34, 20 March 2009 (UTC)[reply]
Assuming of course that the surgeon has not moved on in the meantime and / or that the list is otherwise up to date - I note that a surgeon who operated on me is still listed on the hospital (I went to) pages, despite being suspended from the GMC :( 78.151.212.201 (talk) 21:59, 21 March 2009 (UTC)[reply]
Should I add this to an article? Electrolyzed water applications
This Reuters article caught my eye because I was just reading about other uses for Electrolyzed water. (Just ignore the snake-oil bits, I'm talking about mainstream uses like hospital disinfectants)
The Reuters article talks about using "electrolysis and ultra-low frequency waves" to raise sea water pH to 10 then spraying it in a scrubber stack to knock down soot, SoX, NoX and CO2 in ship exhaust. I wonder if it would also knock down heavy metal emissions, bunker oil being about the dirtiest thing in the world. The method described sounds very much like the process for producing electrolyzed water in commercial applications. (Again, I'm not talking about bottling it and scamming people into drinking it)
My request here is for some sage observers to look at the Reuters and wiki articles and tell me if it would be appropriate to add some verbiage and source to our wiki article to describe this use. And/or feel free to add it yourself!
I can't figure out the ultra low frequency wave bit. About the only thing I can think of is an ultrasonic cleaning effect, but the frequencies used for ultrasonic cleaners are far from "ultra low." (unless they're comparing sound frequency to light frequency but that doesn't make much sense). If the correspondent doesn't have a strong background in science (I have no clue about this guy), another possibility is that he could have messed up somewhere in the terms or facts so ultra low frequency waves refer to something else. Without putting too much thought into this, the alkaline electrolyzed sea water is basically a bleach solution. Perhaps the concept is to oxidize the NO2, N2O, and NO to NO3- and the SO2 to SO4-2? The CO2 I suppose would be removed when it dissolves in the alkaline water to form Na2CO3. I'm a little surprised because the calcium present in sea water would produce CaCO3 which would build up as scale over time which wouldn't seem good for a ship. I am not sure about heavy metals. If they dissolved into the alkaline bleach water it would need to be treated to remove the metals before dumping it back into the ocean. Sifakatalk23:15, 20 March 2009 (UTC)[reply]
There is some more verbiage on the website of Ecospec, the company that is marketing this thing. It sounds suspiciously like those gadgets that you attach to the fuel line in your car, that are claimed to improve your fuel efficiency, and has a familiar lack of any numbers or measurements. Caveat emptor. --Heron (talk) 12:30, 21 March 2009 (UTC)[reply]
March 21
Olaflur
What exactly is olaflur and how effective is it compared with the other forms of fluoride for teeth? Any disadvantages (human toxicity, environmental, etc)? —Preceding unsigned comment added by 79.107.234.164 (talk) 01:25, 21 March 2009 (UTC)[reply]
Our article olaflur will tell you exactly what it is (it is N,N,N'-tris(2-hydroxyethyl)-N'-octadecylpropane-1,3-diaminium difluoride) but will not, alas, answer your other questions. Algebraist01:33, 21 March 2009 (UTC)[reply]
Thank you Algebraist, I have read that, as I have searched in many different sites all of which have the excactly same info as in the article you mentioned. I am particularly interested in the advantages/disadvantages that it has, how it compares with the othe fluoride forms for dental use, it's hazard-toxicological profile and any concerns/other issues about its use. Thanks again though! —Preceding unsigned comment added by 79.107.234.164 (talk) 01:41, 21 March 2009 (UTC)[reply]
Is there a scale that measures how sweet something tastes, similar to how the Scoville scale measures heat? The closest thing I found is the Brix scale, but that doesn't seem to directly measure sweetness. --Ixfd64 (talk) 02:11, 21 March 2009 (UTC)[reply]
For the sweetness scale see e.g. this. I don't think the scale is named after anyone, though; or at least I am not aware of such a name. --Dr Dima (talk) 09:20, 21 March 2009 (UTC)[reply]
Balling, Brix, Oechsle scales all measure specific gravity, and do not measure sweetness directly. In other words, they only indicate concentration of the sugar (sucrose) in the solution, and do not indicate how sweet other substances are compared to sucrose --Dr Dima (talk) 06:46, 22 March 2009 (UTC)[reply]
cacti
Can anyone identify these cacti? Scale is that they are about 2.5" across, and the flowering one is 3.5" tall. Also, would these do ok with only office florecent lights, or do they need actual sunlight?
A Mammillaria sp. perhaps? If I remember correctly the species in this genus can sometimes be tricky to identify. One website suggests partial shade (Filtered sunlight or direct sun for only a few hours) and watering it weekly. Sifakatalk06:04, 21 March 2009 (UTC)[reply]
Why does the depth of field depend on aperture diameter of a lens? I am a bit confused. Aperture is to control the amount of light entering the lens. If I make my aperture smaller, the less light should enter, but focal length is still the same, so how does it affect the depth of field? Thanks. - DSachan (talk) 16:27, 21 March 2009 (UTC)[reply]
It's because aperture appears in the formula for Hyperfocal distance. I have no idea why that is, though! (Our article doesn't seem to explain the formula much.) Hopefully someone more knowledgeable will come along soon... --Tango (talk) 16:40, 21 March 2009 (UTC)[reply]
Actually, after thinking about it, I think I have it - the circle of confusion is going to depend on aperture (in fact, I suspect it is proportional to it), since that confusion is caused by light passing through different parts of the lens ending up at different points on the screen. How far apart those points are is going to depend on how far apart the bits of lens in question are, and a bigger lens allows for greater distances between parts of the lens and so greater confusion. --Tango (talk) 16:44, 21 March 2009 (UTC)[reply]
The diameter of the circle of confusion is proportional to the aperture diameter, and there's an easy way to see that. Assuming an ideal lens, all light rays emitted from a point in the focal plane and passing through the aperture will be focused onto a single point of the detector. Any light emitted elsewhere along the path of that ray, in the same direction, will end up at the same point. So that point on the film will show features lying within a double cone whose base is the aperture and whose apex is the point in the focal plane. A flat object at a certain distance from the focal plane will be blurred by convolution with the aperture scaled by (distance from object to focal plane / distance from aperture to focal plane). This also shows that the "circle" of confusion is really an image of the aperture, and is only circular if the aperture is. -- BenRG (talk) 18:10, 21 March 2009 (UTC)[reply]
With a pin-hole camera - which is a lot easier to think about that the ones with lenses and mirrors and stuff - the smaller you make the pinhole, the better the depth-of-field (but the less light you get in - so the longer the exposure times you need). In the limit - if you imagine a pin-hole camera with an infinitely small hole then every ray of light from everywhere in the world would have to pass through that infinitely small hole in order to hit the film. But only ONE path for that ray is possible. Light (basically) travels in straight lines - but you can only draw one line that goes from some point in the world, through that infinitesimal hole and onto the film. So a perfect pinhole camera has perfect focus from zero to infinity for an infinite depth-of-field. But now imagine a pinhole camera with a 1cm "pinhole" (more like an "ice-pick-hole camera!") - now, the light from a particular point in space can go through the extreme left side of the hole, the extreme right, the top, the bottom, through the middle - or anywhere inbetween. Each of those rays hits the film at a different place - so you get a fuzzy image. If the film is very close to the hole - then a 1cm hole will produce a roughly 1cm blur around a point-sized object in the world. If the film is further away from the hole, then the blurry region will be even bigger. But a perfect pinhole camera has perfect depth of field and everything is always in focus...it just takes you an infinite amount of time to capture the image because you have an infinitely small hole for the light to pass through!—Preceding unsigned comment added by SteveBaker (talk • contribs) 14:14, 21 March 2009
Now you know about that blow your mind out trying to understand Qinitiq's system desribed in [[16]] which can keep the information from different distances sharp. Dmcq (talk) 23:47, 21 March 2009 (UTC)[reply]
No, a metal halide light does not need a high voltage pulse to ignite it, but may need a transformer to convert to the correct voltage. Metal halide lamps may work off the full mains voltage. Graeme Bartlett (talk) 21:20, 21 March 2009 (UTC)[reply]
That is not correct, Graeme. All HID lamps require a ballast, including HPS and MH/CMH lamps, and all require a high-voltage pulse to strike (initiate) the arc. They do not operate directly off mains voltage. Different ballasts are generally required for MH vs. HPS, because of the different run-up and operating voltage requirements; mixing and matching makes problems ranging from the costly and inconvenient (early failure of lamp and/or ballast) to the extremely dangerous (catastrophic lamp failure). However, there are now on the market various "smart" ballasts compatible with more than one type of lamp, usually HPS and CMH. They detect the current draw characteristics of the lamp during run-up, and since these characteristics are peculiar to the different lamp types, the ballast is thus able to "know" what the lamp wants to see in steady-state operation. We presently have two relevant articles, High-intensity discharge lamp and Gas-discharge lamp, though a merger has been proposed. —ScheinwerfermannT·C22:07, 21 March 2009 (UTC)[reply]
Is this Munchausen, or...?
Okay, so if a person knowingly fakes/exaggerates illness/distress, they would be described as having Munchausen disorder; if they create or fabricate illness/distress in a dependent, Munchausen by proxy; do either over the internet, Munchausen by internet. But if a person who engages in all three of the above also mimics real diseases/distresses of their dependents, does that also fall under Munchausen? What if they are a parent who is chronically negligent to an extent that their child(ren) encounter numerous, potentially life-threatening accidents, yet makes no attempt to be less negligent and revels in the attention that results from the child(ren)'s accidents? And what would you call it if said parent, in a fit of new-found religion, demanded that medical personnel announce a miraculous recovery (in the same manner that a standard Munchausener might demand medical treatment), which resulted in the continuation of an injury of the patient that would have otherwise been corrected or at least improved, as a way to self-confirm their religious ideas (note, this would not be in absence of the Munchausen/by proxy/by internet, but rather alongside it...and the treatment avoided by the "miraculous recovery" ultimately causes the injured party permanent disability)?
Munchausen's, and related diagnoses, are extremely controversial - it's not at all clear what (if anything) distinguishes between someone who abuses themselves or others in a medical context and someone who has Munchhausen's. (In other words, couldn't a diagnosis of "Bank Robber Syndrome" be assigned to anyone who robs banks). There are certainly those who claim that Munchausen's simply does not exist, and others that it is greatly overdiagnosed. At best we can say that empirical diagnostic tools for making even a tentative diagnosis are pretty dismal, so parsing the more complex examples you cite seems beyond current analysis. 87.114.29.204 (talk) 20:20, 21 March 2009 (UTC)[reply]
The bible of mental disorders (the DSM-IV) doesn't even list Munchausen - let alone all of these complicated variations. I agree with '87 - this is controversial at best. SteveBaker (talk) 00:36, 22 March 2009 (UTC)[reply]
Thanks Steve, do you think the refusal of medical treatment in order to force confirmation of religious beliefs would also fall under that category, though? bcatt (talk) 05:50, 22 March 2009 (UTC)[reply]
No! The diagnostic criteria is that the person with the disorder wishes to be treated as if they were sick - or in the "by proxy" version wishes someone they care for be treated as if sick. Refusing treatment to someone who actually IS sick (for whatever reason) doesn't sound to me like the same kind of thing at all. I agree with the subsequent posters - sometimes a jerk is just a jerk. SteveBaker (talk) 19:31, 22 March 2009 (UTC)[reply]
Basically we're talking about where you draw the line between a "bad person" and a "mentally ill person that does bad things". I've never really known how that is supposed to work... --Tango (talk) 01:12, 22 March 2009 (UTC)[reply]
People who are rich enough to afford doctors who can make a diagnosis are mentally ill. Everyone else are just healthy people who make bad choices. --Jayron32.talk.contribs02:22, 22 March 2009 (UTC)[reply]
That would seem to suggest that everyone who behaves badly in countries with "free" medical care is mentally ill, and there are no healthy people who have made bad choices in such places. One might conclude then that socialized medicine causes mental illmess, or even that it cures choosing badly. // BL \\ (talk) 04:45, 22 March 2009 (UTC)[reply]
I am personally in Canada, and we have universal health care. I can assure you that many mentally unstable people access the free health care here. Doctors make money from the pharmaceutical companies every time someone fills a prescription, so it's really not that hard to find a doctor who will play along with a mentally unhealthy person's imaginary problems. Also, BL makes a very good point. And to Tango, I would think that all "bad people" have some sort of mental disorder, no? I don't understand the distinction you're trying to make. bcatt (talk) 05:50, 22 March 2009 (UTC)[reply]
When people are mentally ill we don't punish them for their actions or put them in secure mental facilities. When people are just bad we throw them in prison. (That's an oversimplification, obviously, but you get the point.) I'm not the one making the distinction. I agree with you that such a distinction doesn't make much sense - that was the point I was trying to make. --Tango (talk) 13:14, 22 March 2009 (UTC)[reply]
Of course, my response above was somewhat of an oversimplification, but it comes from a basic problem with the mental health industry, indeed one which Tango has aluded to. The deal with most mental illness is that there is a lack of mechanistic explanation for it. If I have diabetes, its because my pancrease doesn't work right. If I have AIDS, I have a virus in my system which is causing it. If I have ADHD, it means I display a set of behaviors, but what is the underlying physical cause of this?!? See, there's the crux of the problem. Diseases have causes which can be identified. Mental diseases, mostly, are about a set of causeless symptoms; so what sepereates a person who chooses to behave badly from one with a mental illness is simply the existance of a doctor willing to provide the diagnosis. Now, don't get me wrong, there are real mental illnesses. I understand this; however there are also a vast number of people who are overdiagnosed with them, because there is no way to distinguish between people who make bad choices and people who are incapable of making good ones. It;s a shame, because it swamps the system with people who don't need treatment, and reduces the quality of treatment to people who really need it. So people with access to the doctors to make the diagnoses get labeled "unable to make good choices" and those people without get labeled "people who make bad choices". It is unclear what is wrong inside of their bodies that distinguishes one group from the other... --Jayron32.talk.contribs01:07, 23 March 2009 (UTC)[reply]
Ok, I have a lot easier time agreeing with you on these points. Coincidentally (or not), ADD/ADHD appears to be one of the favourite diagnoses of the type of parent that I've described, as well as of every damn teacher out there who expects a child to engage in the completely abnormal behaviour of sitting at a desk for 7 hours 5 days a week...it's simply unnatural. bcatt (talk) 16:19, 23 March 2009 (UTC)[reply]
March 22
Pick on somebody your own size...
Why is it that the largest animals, both on land (elephants) and in water (whales), don't have any natural predators (other than man, that is). I'm talking about adult animals here. So, why isn't there a predator (or group of predators) large enough to take on an adult elephant or adult blue whale ? Somehow the upper size limit for predators seems to be lower than for other animals, but why exactly is this ? StuRat (talk) 04:23, 22 March 2009 (UTC)[reply]
If the largest animals in the world were predators, they would quickly outstrip their food source, and then ensure their own demise. The situation is not unique to modern times, Tyrannosaurus, one of the largest predators ever, was still dwarfed by contemporaneous herbivorous dinosaurs; probably on a scale similar to the size difference between the largest predators and herbivorous animals today. Incidentally, Blue Whales are technically meat-eaters; they subsist on Krill, which is definately not a plant. --Jayron32.talk.contribs04:41, 22 March 2009 (UTC)[reply]
Why couldn't there just be fewer in the predator species than their prey species ? I believe this is the normal situation in any predator-prey relationship. StuRat (talk) 04:47, 22 March 2009 (UTC)[reply]
Well, we could invent any situation we want to; except that time and time again, over history, the same patterns have emerged. We can justify these repeating patterns, by offering explanations as I have done, but offering counterexplanations (like "we SHOULD have really huge predators") doesn't make much sense, since it just appears to not work that way. Except that, as I noted above, the largest animal ever to have lived, IS A PREDATOR. Blue Whales eat other animals, live, which seems to me to be what a predator does... Even if you don't want to include that as a predator, you must admit that predators just AREN'T the largest critters in any environment and at any time, so explanations that attempt to say they should be must be flawed from the start, no? --Jayron32.talk.contribs05:09, 22 March 2009 (UTC)[reply]
Keep in mind that the larger the animal, the longer it takes to grow a replacement. In general, anyway. Preditors can eat rabbits all day long and the population will rebound quickly. If a theoretical uber-hunter ate all the elephants within its range in could be decades before they replenished. It seems like that would leave a very low margin of error for the predator-prey balance.
Incidentally, while adult elephants have no natural predators other then humans, juveniles are general vunerable to big cats although the social herd nature helps to protect them.. The same appears to be the case for mammoths and saber-toothed cats and one common believe is the demise of the mammoths may have played a role in their extinction, take a read of Homotherium and Smilodon for example. Homotherium in particular says
Friesenhahn cave in Texas contained the remains of over 30 H. serum individuals, which were discovered along with the remains of between 300 and 400 juvenile Columbian Mammoths (Mammuthus columbii).[6] Besides mammoth, very few other potential prey species were found in the cave - it is therefore unlikely that Homotherium carried scavenged carcasses of already dead animals to the cave. Such specialization on prey of a particular species and age structure is not covenant with a scavenging lifestyle. For the same reason it is also unlikely that the dire wolves carried the mammoths into the cave.
Wow, they are 1/25th the mass, so that would seem rather ambitious. That's worse than a house cat hunting an adult human. StuRat (talk) 17:22, 22 March 2009 (UTC)[reply]
I think that they only go for the calves and they do hunt in packs, so maybe not so ambitious, although such attacks are said to be rare in our article. Mikenorton (talk) 17:37, 22 March 2009 (UTC)[reply]
Still, there have been cases where a dog of a similar size to a housecat has managed to kill an adult human. I'm not entirely certain - but I think that killer whales are much faster and more manoeuvrable than blue whales, and they are (obviously) much more aggressive. Blue whales are huge, yes - but I'd imagine that taking a chunk the size of a killer whale's mouth out of the body of one would cause it to die. --Kurt Shaped Box (talk) 22:33, 22 March 2009 (UTC)[reply]
There are plenty of ecosystems where the dominant predator is also the largest animal. The Killer Whale eats penguins and seals - and is easily the biggest animal that lives (continuously) in those areas. I doubt that in regions where the Great White Shark lives has any animals that are any larger. Ditto Polar Bears, ditto Grizzly Bears. I think there are plenty of ecosystems where the predator is the biggest creature around - and plenty of others where it isn't - it seems fairly random to me. As for the evolutionary pressures - I agree with the earlier respondant - if an easier living can be had hunting rabbits - why go after elephant? If the only herbivore was the elephant - then probably the carnivores would evolve to take it down. But generally a pack of animals is better at doing that...and for that, size isn't everything. SteveBaker (talk) 19:26, 22 March 2009 (UTC)[reply]
Are you sure no whales live in those oceans ? And how about large land herbivores, such as elk and moose ? They seem like they might be too big to be prey for bears, at least the adult males. As for your "if an easier living can be had hunting rabbits - why go after elephants ?", the point is that the rabbit-hunting niche is already filled by well-adapted predators, while the whale- and elephant-hunting niches are wide open. StuRat (talk) 03:34, 23 March 2009 (UTC)[reply]
Healthy adult sauropods (of the 'giant' type), I'd guess not. I'll bet that there were plenty of predatory dinos that could and would take a young one, or finish off a sick one, though. Predators don't generally attempt to take on prey animals that look as though they might have a good chance of defeating them in combat unless they're really desperate for food. --Kurt Shaped Box (talk) 23:58, 23 March 2009 (UTC)[reply]
I have sprayed a Kaffir Lime tree with a pyrethrin product to eliminate a heavy infestation of red spider mites. Since I use the leaves in cooking, IS IT SAFE to eat the food cooked using these pyrethrin-sprayed leaves? Is there a period of time after spraying not to use them, and then it is OK?
Pyrethrins are amongst the safest pesticides available. Having said that I'm loath to pronounce anything completely safe. You should judge for yourself from the published information about them, here are a couple of links that discuss both direct exposure [18](i.e. during application) and safety as residue in food [19]. The conclusions seem to be that there are few definite health implications but the possibility of carcinogenesis has not been ruled out. Mikenorton (talk) 12:43, 22 March 2009 (UTC)[reply]
Next time spray the Kaffir Lime with plain water more frequently, two or three times a day if possible. Red spider mites hate moist conditions and will find it hard to survive let alone flourish. Richard Avery (talk) 08:30, 23 March 2009 (UTC)[reply]
In the instruction manual of your pesticide (or on the bottle) there is probably some direction about the use on food crops (which probably includes directions on long you have to wait). If not, at the very least there should be a telephone number for the manufacturer. I highly recommend calling them and asking their recommendation on the matter - especially with potentially hazardous things such as pesticides, I find that most manufacturers are happy to discuss how to use their product safely. -- 76.204.102.79 (talk) 03:19, 25 March 2009 (UTC)[reply]
Metal spoon in microwave
Hi. Sometimes we leave a metal spoon in our food when we put it in the microwave, and nothing happens, and the spoon is barely hot afterwards. Of course, the food must be full, solid, and in a bowl, and most of the spoon is immersed in the food so the microwave isn't heating *just* the spoon. Are there any risks that are unforseen with this practice, such as radiation being emitted outside of the microwave, or the spoon or the food storing excess radiation or an electric current, etc? Thanks. ~AH1(TCU)14:56, 22 March 2009 (UTC)[reply]
It does however say "Microwaving food containing an individual smooth metal object without pointed ends (for example, a spoon) usually does not produce sparking". There is a risk of shorting if the handle gets too close to the side of the oven. I can't see how any excess radiation or electric current could be stored. Mikenorton (talk) 15:25, 22 March 2009 (UTC)[reply]
Well, there are certainly situations when this practice is "A Bad Thing" - sharp metal objects concentrate the charge at their tips and can arc - that produces all sorts of nasty, toxic gasses that you really don't want in your food - also, metal objects positioned "just so" with respect to the microwaves resonant cavity can concentrate the heat in small areas resulting in food that's cool in some areas and dangerously hot in others - that can result in small explosions when heating liquids - it can also "short out" the magnetron to some degree which will shorten it's life and might even outright destroy it. However, there are other times when none of these terrible things can happen. However, the precise reason you get one outcome versus another depends critically on exact placement of the metal, its exact shape and the precise nature of the food (if any) around it. Since we mere mortals have ZERO 'gut-feel' for what's right and what's not when it comes to invisible & intangiable things like microwaves - putting metal that was not designed specifically to be there into your microwave - is just a dumb thing to do. It says that right there in the instruction book for your oven - and there is probably another sticker someplace on the door frame that says it again...they don't do that without a reason...so just don't do it - OK? SteveBaker (talk) 19:17, 22 March 2009 (UTC)[reply]
Let me reword the OP's question a bit to understand it a bit better... "See, this one time, I crossed a busy street wearing a blindfold and blasting my I-pod. I could see nothing, I could hear nothing, and there were like 100 cars crossing the street in front of me. And yet, I didn't get hit. Doesn't this mean that all the things I read about looking where I am walking and only crossing with the light are bullshit? Like, if I managed to cross the street with a blindfold and nothing bad happened, why is there all this fuss?!?". Seriously, putting metal in a microwave is ALWAYS contraindicated, even if occasionally nothing bad happens, it is NOT a habit you want to get into... --Jayron32.talk.contribs00:49, 23 March 2009 (UTC)[reply]
When I was a little kid, I saw a wildcat (Bobcat) in a cage at a roadside zoo. I stuck my finger through the chickenwire of the cage to tease the cat, and suffered no ill effects. Around the same time, I stuck my finger in a live electric socket, and suffered only momentary pain.Around this same time, while walking in high weeds in the southern U.S, I stepped on a snake (of unknown species) which thrashed around dramatically. Can we conclude from these anecdotal reports that these actions were a good idea? Edison (talk) 02:25, 23 March 2009 (UTC)[reply]
, still a spoon is a heck of a lot safer then a fork, so maybe the ipod was not on full blast and the blindfold let you get a glimpse of shadow vs light.65.121.141.34 (talk) 14:03, 23 March 2009 (UTC)[reply]
ATTN Steve Baker - do we really have complete dinosaur dna like in Jurassic Park?
Dear Steve Baker,
My question is: have we really got complete dinosaur dna like in Jurassic Park? Eventually, does it look like there is any reason we couldn't really hatch little dinos?
I'm not sure why you are specifically asking Steve, he wasn't a palaeogeneticist (is that a word?) last time I checked. I'm pretty sure we don't have a complete genome for any dinosaurs - they didn't even have one in Jurassic Park, they had to fill in the blanks with frog DNA (why they didn't use bird DNA, I don't know... probably because the plot wouldn't have worked!), or something, which is what caused all the problems. Our article, Dinosaur#Soft tissue and DNA, suggests we haven't even got a reliable partial genome from any dinosaurs (a couple of unreliable ones, though!). --Tango (talk) 15:33, 22 March 2009 (UTC)[reply]
I'm asking Steve Baker because he's the smartest and best-informed paleogeneticist in existence -- paleogeniticists might not exist as a profession, yet Steve Baker would be the best qualified of them all (if not best-credentialled). Thank you for the link. However, with the above points in mind, I will wait for Steve Baker's verdict. Thank you! 94.27.132.205 (talk) 15:46, 22 March 2009 (UTC)[reply]
Steve is very well read and an excellent researcher, but what gives you the idea he's a well qualified palaeogeneticist? --Tango (talk) 16:20, 22 March 2009 (UTC)[reply]
(edit conflict)Even with an animal as geologically recent as a mammoth, paleogeneticists (6660 ghits BTW) have only assembled part of the genome and in this BBC article [20] Dr Gilbert of Copenhagen's Center for Ancient Genetics says that even if we had the whole genome "technology does not currently exist to turn that biochemical information into a live animal". Mikenorton (talk) 15:50, 22 March 2009 (UTC)[reply]
If you really are only interested in answers from Steve Baker, then you should ask this Q on his talk page, not here. If you want answers from everyone, then post here, but don't address those Q's to any particular person. StuRat (talk) 16:02, 22 March 2009 (UTC)[reply]
We barely have a complete human genome, and there's no shortage of fresh, brand new, human blood. Only very tiny, and (obviously) very old samples of dinosaur blood and soft tissue have been recovered. It's not clear if it's even theoretically possible to extract a complete dinosaur genome from these samples (It's possible that the information we'd need simply doesn't exist anymore.), but even if it is, we'd need technology much more advanced than we've got now. APL (talk) 17:10, 22 March 2009 (UTC)[reply]
I certainly feel like Moses and maybe shouldn't be asking back, but although I understand #1, could you explain the reasoning for #2? I mean, "eventually" is a long time, even if we had to combine 100,000 bits of DNA, there ARE that many in total waiting to be unearthed, no? Couldn't they be combined? If all you have is a very poor (less than VGA) webcam and want a super-super high-resolution scan of something -- couldn't you get it through 100,000 passes? Or in this case, you would have 100,000 deteorated photographs, coudln't you come up with the original based on all that? —Preceding unsigned comment added by 94.27.132.205 (talk) 19:16, 22 March 2009 (UTC)[reply]
Maybe. The problem with DNA is that, while you may have all the bits necessary, you wouldn't have any way to know what order to put them together in. Your photograph analogy doesn't quite work - a better analogy would be a puzzle for which we don't know the image we are supposed to be putting together. --Tango (talk) 19:45, 22 March 2009 (UTC)[reply]
I mean the image of the DNA. We are far from being able to backwards engineer DNA from observations of fossilised bones. --Tango (talk) 20:22, 22 March 2009 (UTC)[reply]
The problems with making a creature from scratch goes a long way beyond just assembling a viable DNA strand. You've also got to implant it in a suitable cell (ie one that has the right chemical environment, etc) - that has to be provoked into replicating by the right chemical setup in the mother - in the case of Dinosaurs, something has to create a huge egg - and lay it and hatch it. The way we clone animals right now is to take the egg from a closely related animal, wipe out its DNA and replace it with the new DNA. Then you implant the cell back into the female of the closely related species and wait for nature to take its course. However, we don't have any extant animals that are anything remotely like a Dinosaur. So we have no egg to implant the DNA into - and no mother dinosaur to implant the egg into. Worse still, it's very likely that all of the food that a baby dinosaur would be able to eat has long gone extinct - so you have a problem feeding it. Because we have no live dinosaurs to study - we don't even have a way to know what nutrients they need. Also, the world has changed quite a bit - different amounts of oxygen in the air - that kind of thing. Most animals get resistance to disease from their mother's antibodies - no chance of that happening here. The obstacles are spectacular...even if you could get an intact DNA strand - which isn't looking very possible from the amounts we've been able to extract. Remember that you can't just collect random DNA snippets from 500 different species spread over 160 million years and expect to be able to stitch them all back together! You need DNA from a single species...perhaps even a single sex of a single species...and over a few thousand years or so. That's asking a lot! SteveBaker (talk) 19:56, 22 March 2009 (UTC)[reply]
It doesn't need to be a huge egg, there were plenty of small species of dinosaur we could try and bring back. We don't have the technology now, but I don't see any theoretical reason why a synthetic egg wouldn't be possible to construct eventually. I think the DNA is the biggest problem, the rest can be overcome with effort but if the DNA doesn't exist, then it doesn't exist. --Tango (talk) 20:22, 22 March 2009 (UTC)[reply]
I'm no SteveBaker, but here's my take.
1.) Not yet, but theoretically possible given a well-preserved specimen. There has been some progress in sequencing the Neanderthal genome but there are still considerable gaps. Another concern is that even if you could piece together a "complete" genome for a given dino species it would almost certainly be a patch-work of pieces from different individual specimens and would utterly fail to capture the degree of genetic variation that would have existed within a population of that particular species. This would lead to considerable trouble with part 2 and any future breeding of your little dinos (which would all be genetically identical to each other -- not good for the health of the species).
2.) Without extraordinary advances in molecular biology, NO. One reason is that even if you knew the complete DNA sequence based on sequencing fragmented pieces of dino DNA, you'd still have problems assembling it into the proper chromosomes that would enable the putative dino cells to replicate. The way the sequencing of the human genome was done, large fragments of DNA contained in bacterial artificial chromosomes were sequenced and mapped to their proper chromosomes, then overlapping fragments were pieced together to generate a computational "assembly" of the genome that is now an advanced draft stage (there are still bits that haven't been sequenced due to their complexity or repetitiveness). We know the structure of human (and mouse, and fly, and dog, etc.) chromsomes because of cytogenetics, fluorescence in situ hybridization, and other such techniques -- which require intact cells and in some cases cell culture. Mapping the fragments of dino DNA to their proper locations within the dino chromosomes would essentially be impossible because of the inability to perform cytogenetic techniques. Furthermore, even if you knew where each piece was supposed to go, we don't currently have the ability to stitch together an entire chromosome "de novo" and somehow get it to assemble into its proper macromolecular structure, complete with histones and all the other DNA binding proteins that endow the DNA with the ability to be replicated in a living cell. Now, it is theoretically possible that you could get enough of the dino DNA to make a "complete" sequence and somehow "splice" it into existing chromosomes from a modern-day species (as was the plot in Jurassic Park) but this would be extraordinarily challenging (dare I say "impossible"?) for today's molecular biology. --- Medical geneticist (talk) 20:25, 22 March 2009 (UTC)[reply]
What about this iterative proposal: put the large species in a small species so that it's cramped and deformed, but alive, at birth. Then put the DNA straight back into the new girl once she's an adult (no CHANGE in the dna). It might still be cramped because of the deformity but basically should be normal. A final few generations the same way will result in a perfectly fit dino -- raised in as good a womb as you get (or whatever cold-blooded lizards have instead of wombs). What do you think of this proposal? 94.27.132.205 (talk) 20:40, 22 March 2009 (UTC)[reply]
See ALL of my objections above. You might maybe be able to get around needing a big egg that way - but you still have no cell to put the DNA into, no parent animal to implant the egg into, no food for the hatchling, no knowledge of how young dinosaurs have to be treated by their mothers - whether the temperature of the egg has to be varied during development (this turns out to be a CRUCIAL factor in the development of Turtles and Crocodiles...so it's probably critical in Dinosaurs too)...there are a million things we don't know (and arguably, cannot know) about raising a dinosaur. When you consider how many species have proven impossible to breed in zoo's - and that's with full knowledge of diet, parenting, etc, etc...this is so far from being possible. Heck, your first step would have to be in assembling lots and lots of plant DNA from species of that era and figuring out how to grow that BEFORE you even start on the actual Dinosaur. SteveBaker (talk) 21:02, 22 March 2009 (UTC)[reply]
I, for one, am very comfortable leaving it to Steve to determine whether paleogeneticists have access to complete dino DNA at this point. Edison (talk) 02:20, 23 March 2009 (UTC)[reply]
Birds are considered the modern descendants of dinosaurs so just hatch an egg and you've got yourself your own little baby dinosaur. It may be possible to get something like a dinosaur by seeing what's common between birds and crocodiles say and then cutting out a selection of those changes which are specifically for bird like features like beaks and putting in some of the more dinosaur like things that have their remnants in the junk dna and occur in crocodiles.
Or breed parrots? A lot of baby parrots look like mini 'raptors for the first few weeks after hatching. Probably sound a lot like them when they're begging for food too. --Kurt Shaped Box (talk) 21:41, 23 March 2009 (UTC)[reply]
I was watching videos of cats falling and being okay--but some of the heights impressed me! If I fell from the same height, I'd be seriously hurt, how do they do it?!24.91.161.116 (talk) 15:48, 22 March 2009 (UTC)[reply]
The lighter the animal the farther it can fall without injury. With a small enough animal, like an insect, it could fall from an airplane and survive, as it's terminal velocity is too low to be, well, terminal. StuRat (talk) 15:56, 22 March 2009 (UTC)[reply]
I don't think it's just mass that's a factor, it's the ratio of mass to the area of animal projected onto a plane. Since mass is roughly proportional to volume (different animal have similar densities), which is proportional to the cube of linear size, whereas area is proportional to the square, smaller animals have an advantage over larger ones. With cats there is more to it, though, since they can self-right so their legs hit the ground first, allowing them to absorb the impact better. --Tango (talk) 18:25, 22 March 2009 (UTC)[reply]
If I drink something with 2 straws in my mouth does it take more or less sucking power to get the same amount of liquid as with 1 straw. How about with 15? I'm looking to find out the most effective number of straws, where I exert the least amount of energy for the most amount of liquid pay-off.24.91.161.116 (talk) 15:51, 22 March 2009 (UTC)[reply]
I'd say one straw is best. Two would at first seem to be the same, but there is likely to be an air gap between the straws which allows some of the suction to be wasted by sucking in air. The more straws, the more likely you will have air gaps. StuRat (talk) 15:58, 22 March 2009 (UTC)[reply]
I wonder what the efficiency of sucking through a straw is... if it's very efficient to start with (and I have a feeling it might be) then adding more straws won't be able to help. The only losses I can see would be from an imperfect seal around the straw (which is probably negligible with one straw) and the usual losses associated with any muscle usage (in this case, the diaphragm). --Tango (talk) 16:40, 22 March 2009 (UTC)[reply]
It's a simple matter of conservation of energy. The liquid is raised to some height - so it gains gravitational potential energy in proportion to (mass x :height) - that's the amount of energy it costs you to lift it through that height. So, neglecting friction and such - there is no difference in the energy required. That's certainly a reasonable assumption for drinking (say) water - but milkshakes are non-Newtonian fluids and their viscosity doesn't behave in a simple way. But in any case - assuming the two straws could be said to be independent - moving X amount of liquid through one straw ought to take the same amount of energy as X amount through two. So this is really a question of efficiency - can your mouth muscles (or rib muscles or diaphragm) produce that energy more efficiently in short-high-power sucks or better in slower, low-power sucks. Think of how your car uses more gasoline if you drive around all day with the tachometer pegged at 6,000 rpm instead of 2,500 rpm. Sadly, the human body is ridiculously complicated - and so that's an insanely difficult question - so probably you need to do a series of serious (albeit delicious) experiments to figure it out. SteveBaker (talk) 18:47, 22 March 2009 (UTC)[reply]
I believe that the viscosity of a milkshake is the main factor limiting flow rate, not the potential energy between the top and bottom of the straw due to gravity. The flow should be approximately proportional to the pressure differential created by sucking (atmospheric pressure minus intra oral pressure) divided by the resistance to flow through the straw, analogous to Ohm's law for linear electrical resistances. The lips, being flexible in the normal person, can seal around two straws as well as around one, especially if they are a short distance apart so there is not a failure to seal between them. Two straws=twice the milkshake per second, with the same suction created by the mouth. Two straws is like a larger straw (but wall effects may prevent a simple relation to the area of the straw opening). The failure to linearly keep increasing the flow with more and more straws would be due to the inability of the mouth to maintain the same high suction when a high flow rate enters, as well as leakage between adjacent straws. Edison (talk) 19:06, 22 March 2009 (UTC)[reply]
WP:OR: (I couldn't help it) with 8 oz of low viscosity liquid (water) and there is a learning curve:
Since there is, as you say, a learning curve, we need to know what order you did the trials in in order to interpret the data. --Tango (talk) 00:02, 23 March 2009 (UTC)[reply]
I have altered the table above to provide clarity as to the trial counting:
You can tell I am not a scientist. From the layout by itself, I assumed Trial 1 was first one straw and then two straws; Trial 2 was one straw and then two straws. You are right that it doesn't say that, though. // BL \\ (talk) 00:39, 23 March 2009 (UTC)[reply]
I recruited an independent referee to do the timing with a one second resolution timer. My challenge was to empty a measuring cup filled with 8 ounces of water with either one or two drinking straws by sucking the water into my mouth and then spitting it out into the adjacent sink in the fastest time. We then practiced a few times withan empty cup to be sure of the cues.
Show time: When she started the timer and said "go" I did the best I could to empty the cup as fast as possible and then declare "stop" while putting the cup down onto the counter (where it started) and then she stopped the timer. I then recorded the elapsed time. The testing trials alternated between between using one and two straws starting with one straw and finally ending with two straws (eight trials in all). The "spitting out" time seemed to go much faster than the "sucking" time that I attribute much of the "learning curve" to the "sucking" part. The apparatus consisted of a 12 ounce graduated clear glass measuring cup with a handle and "squash-proof" plastic drinking straws 7.75 inches long by 0.25 inches diameter. The water was about 48ºF. The referee thought I was nuts! -hydnjo (talk) 01:07, 23 March 2009 (UTC)[reply]
I've replaced the other responses to this question that you removed and moved your latest reply to the bottom - you managed to completely mess up the section!! (We've all done it, don't worry!)
So the conclusion we should draw from this extremely scientific and reliable experiment is that there is no significant difference between one straw and two for drinking water. Thank you for sacrificing your reputation for sanity for the sake of science - I salute you! --Tango (talk) 01:16, 23 March 2009 (UTC)[reply]
USE A MILK SHAKE! Don't spit it out, to avoid lots of wasted time. SWALLOW IT! Water is very low viscosity, so the limiting factor is likely the ability of the tongue and jaws to pump liquid, rather than the rate of flow of a viscous liquid through one or two tubes at constant pressure. Edison (talk) 02:14, 23 March 2009 (UTC)[reply]
Whilst generally in favor of the scientific method - I can't help thinking that our most dedicated test subjects may have trouble maintaining a uniform performance after consuming approximately 8 milkshakes...and that's before we begin to concern ourselves with control groups for the influence of extra chocolate on the viscosity. SteveBaker (talk) 12:36, 23 March 2009 (UTC)[reply]
The low flow rate with a thick shake might allow consumption of a small amount per trial. 3 ounces, maybe? There would probably be lots of volunteer experimental subjects outside a malt shop/McDonalds on a nice day. Edison (talk) 18:41, 23 March 2009 (UTC)[reply]
A useful experiment might measure the flow rate of a viscous liquid through one versus two or more straws, placed such as to allow the lips to seal around them. Weigh the source vessel containing the milk shake, have the experimental subject suck on 1 or 2 straws for a short period such that mechanics of swallowing or spitting out are not a factor, and weigh the source vessel to see how much was consumed in, say 2 seconds, such that the mouth can maintain approximately constant suction. Edison (talk) 03:11, 24 March 2009 (UTC)[reply]
Injuries causing memory loss
Hi all I am researching injuries that can cause memory loss. By this I mean memory loss that occurs as a result of an accident, most likely a head injury in this case, as opposed to the likes of Alzheimer's or Parkinson's disease causing memory loss. I have read about the likes of chronic traumatic encephalopathy (punch drunk syndrome), subarachnoid haemorrhage, skull fractures and concussion causing memory loss. (Only temporary with regard to concussion). My question does anyone know if I have missed out any injuries which can result in memory loss? If so could they give me some pointers as to where I can find out more information on them? Many thanks. —Preceding unsigned comment added by 139.222.240.10 (talk) 20:45, 22 March 2009 (UTC)[reply]
Apologies, I know you guys must get stupid questions like this alot, but I cant get a straight answer anywhere else.
From this quote "A potentially promising area for research is the fact that if particles become more energetic as they are heated or accelerated their gravitational field increases. Changes in gravity can perhaps be attributed to a change in a spherical zpf energy density gradient surrounding an accelerated or decelerated massive particle." It seems to suggust that the zero point field can effect gravity, and the casimir effect moves objects, would it be possible , If we had better tech than we do now, to make a device that can manipulate zero point energy to move objects like the gravity gun if halflife 2 for example. I know this is stupid question but i cant get a strait answer from anyone about this, if not thats fine , if so thats fine too, if opinions are devided who current has the strongest case scientifically.
The Casimir effect is a fairly weak force equivalent to van der Waals bond. It's potential energy must be very low and contribute very little to a measured mass. Its effect will be the greatest on the smallest scales, such as between nucleons. However this mass would already be measured when the mass of nuclei is determined, so there should not be lots of spare energy there for the taking. This force is what gives grease its strength. Graeme Bartlett (talk) 04:24, 23 March 2009 (UTC)[reply]
protonation of the alcohol group in 2-methylcyclohexanol
In order to protonate the OH group with phosphoric acid to weaken the C-(H)OH bond so a dehydration elimination reaction can occur to yield 1-methylcyclohexene, does this mixture need to be subjected to heat? At what stage of the mechanism for the elimination reaction is heat needed? John Riemann Soong (talk) 01:42, 23 March 2009 (UTC)[reply]
Heat probably doesn't affect the extent of protonation much. However, heat probably does promote loss of water because that is a fragmentation reaction, and increasing temperature makes this change in entropy an increasingly important part of the overall energy of the reaction. Heat also makes all reactions faster, so you'll be able to get out of lab in time for the next class:) DMacks (talk) 01:49, 23 March 2009 (UTC)[reply]
Well, I'm a bit confused by my lab manual. It seems to imply that the thermodynamic stability difference between 1-methylcyclohexene and 3-methycyclohexene is greater than the stability difference between 1-methylcyclohexene and 1-methylcyclohexanol. If I look at it a certain way, it almost seems that the 1-methylcyclohexene product is lower in energy than the alkane product! I'm wondering at what point the heat input is critical for what must be an endothermic reaction (reversal of saturation/addition of an alkane). And the protonation of the OH group appears to require the greatest activation energy in the reaction. I know heat aids in reactivity, but surely it can't be just that (as well as yes, the steam distillation of my product?) According to the energy diagram, the loss of the water molecule after the alcohol has been protonated is exothermic so heat would only appear to aid in speed of the fragmentation step. John Riemann Soong (talk) 02:15, 23 March 2009 (UTC)[reply]
If you have the actual energy diagram, then you know exactly where energy needs to be added to make the reaction go:) I assume that it is ΔG, so steps where ΔS changes are generally the ones that are the most affectable by T. You always need energy to get over the activation barrier, but once you have "at least that much", the equilibrium will always be establishable. And no matter what the role of heat may be in the chemistry or where each equilibrium lies, "removing the product as soon as it's formed" is going to drive an even fairly unfavorable (by product stability) reaction, thanks to Le Chatelier. Once you're steam-distilling the product out, that's all that really matters for accomplishing this reaction in practice. DMacks (talk) 02:29, 23 March 2009 (UTC)[reply]
I'm not sure if the diagram is being held at constant temperature though. Fragmentation generally would be exergonic yes? It wouldn't be that elevated temperature between the protonation and fragmentation steps allows fragmentation to proceed, e.g. s*dT exceeds a positive dH? I'm confused about energy flow -- e.g. whether the diagram includes the phosphoric acid in the system or not. The lab manual says the phosphoric acid "catalyses" the reaction so would it be that the H+ is what injects free energy into the system before the mixture is heated? Removing the product sounds really promising as a "drive" for the reaction, except I think the methylcyclohexanol is being distilled too (along with the aqueous components). Is this where volatility and vapor pressure would start to be important as well? I'm trying to finalise my understanding of this process. Thanks for all the help anyway! John Riemann Soong (talk) 05:19, 23 March 2009 (UTC)[reply]
Also, I note interestingly that methylcyclohexanol has a boiling point of 165-168 degrees Celsius. It's miscible with water, so it would probably form some kind of azeotrope and I'm correct to assume it wouldn't boil at significant amounts at 96 degrees Celsius compared with the methylcyclohexenes (bp 104-110)? John Riemann Soong (talk) 05:19, 23 March 2009 (UTC)[reply]
Folic acid
I'm currently working on a spoken version of folic acid. However, as I was going through it for a quick copyedit, I ran into a problem; the equation at the end of the section Biochemistry of DNA base and amino acid production seems, to me, to be nonsensical. I'm having difficulty determining what it's actually supposed to be. Is it wrong, or is it just my sight beginning to blur from too much editing? If someone could take a look at it, I would be much obliged. Thanks! Sophus Bie(talk)10:00, 23 March 2009 (UTC)[reply]
For my science class on a project, we have to draw a scaled drawing showing improvements we made to a windmill. How would I show that I made the turbines out of carbon fiber? <(^_^)> Pokegeek42 (talk) 13:13, 23 March 2009 (UTC)[reply]
By writing "carbon fibre" next to them. Technical drawings are often annotated to include information on construction materials and lots of other stuff. --Tango (talk) 13:23, 23 March 2009 (UTC)[reply]
Maybe you could copy (as in make a similar drawing not photocopy) a micrograph or show how the fiber reinforces the material [21]. Then compare to other materials and say why carbon fiber is better. or do s.th. like Crystal structure. You could also do a drawing of the windmill shaded with areas showing high strain and how your carbon fiber would be an improvement there. S.th. like this would be over the top. [22]. Just get some colored pencils and shade in a turbine image.76.97.245.5 (talk) 13:51, 23 March 2009 (UTC)[reply]
Tango's absolutely right. Use any method that makes your intention clear. I've recently been involved in a rather large construction project and, besides the sheer volume of drawings required, which is staggering, I've also noticed that formality tends to go out the window if there's a more clear way of expressing what you need to. Matt Deres (talk) 19:56, 23 March 2009 (UTC)[reply]
Given that this is a school project the prime target is to impress the teacher, not necessarily communicate with the reader. So something that shows a little effort will help. 76.97.245.5 (talk) 12:42, 24 March 2009 (UTC)[reply]
Probably "purging of toxins". In this case, no, not to any significant degree. Also, it's a mistake to believe that we are all suffering from mysterious unnamed "toxins" in the first place. This is just a marketing scam. StuRat (talk) 15:53, 23 March 2009 (UTC)[reply]
Another possible interpretation is that they are asking if microdermabrasion can cause vomiting. I sure hope not. If so, I'd never do that again. StuRat (talk) 15:55, 23 March 2009 (UTC)[reply]
There is certainly a lot of crap out there about these 'toxins' and things you need to get rid of or deal with. Our bodies pretty much maintain themselves - there are very few things we need to do to it to allow it to keep functioning efficiently. The skin sheds cells very effectively without dermabrasion. Our kidneys filter out most kinds of routine toxins and flush them out when we pee. None of these silly treatments are needed for a normally functioning person. We'd never have survived all of those hundreds of thousands of years without these things if our bodies were really that pathetic. So eat sensibly - exercise moderately - bathe periodically - and you're doing about the best you can. SteveBaker (talk) 11:27, 24 March 2009 (UTC)[reply]
Part of this toxins scam is the claim that they are all a recent occurrence; chemicals created as part of our modern industrial world. In some parts of the world with dismal environment practices, this may actually be true. However, in the West, most of us don't absorb this level of toxins (except for smokers, perhaps). And, in any case, all of these "cures" that promise to remove the toxins are unable to remove a significant portion. StuRat (talk) 14:44, 24 March 2009 (UTC)[reply]
Monophyly of amphibians
Nowadays, the consensus is that amphibians form a monophiletic group. Nonetheless, in the past there was much debate over whether they were paraphyletic (i.e., amniotes descend from them). I have looked in Amphibian articles on Wikipedia and I have done google searches, but I haven't found much; does anybody know some place where I might find an in-depth discussion of the taxonomy of amphibans over the last few decades? Thank you. –Leptictidium (mt) 19:43, 23 March 2009 (UTC)[reply]
I doubt this is part of your problem but monophyletic is the correct spelling. Some of the references in this article may help. The American Museum of Natural History seemed to have overhauled its taxonomy system and googling this may lead to relevant information. This paper, THE AMPHIBIAN TREE OF LIFE, by the American Museum of Natural History seems to go over the various DNA tests, the reasoning for classification, and what changes they suggest in taxonomy. I would raid the sources and check out other works by the authors to look for more material on the topic. I found that paper by googling "Amphibian taxonomic philosophy" without the quotes. Sifakatalk17:18, 24 March 2009 (UTC)[reply]
Expansion of Space
I have a hard time understanding what we mean when we say our universe is expanding. What exactly is expanding? Is it the distances between all cosmological objects? (Are these objects themselves expanding?) If it is, where is it expanding to? Where does this extra space come from? If I get it right, it is the space itself which is expanding. If it is so, is it expanding into its own dimension? I mean in 3 dimensions or something else is going on here. If we assume a hypothetical picture of seeing the universe from 4th dimension, we will see its edge. is this edge moving outside? If yes, what is this outside and what is this outside composed of? Please clarify. - DSachan (talk) 20:11, 23 March 2009 (UTC)[reply]
"What exactly is expanding?" pace itself is stretching
"Are these objects themselves expanding?" Objects that are gravitationally bound like galaxies and solar systems are not expanding. Larger objects like galaxy super clusters may still have some residual expansion but could possibly complete their gravitational 'colapse' in the future and become bound, after which the space within them would have stopped expanding (Only at a very large scale the universe can be considered to have a uniforme rate of expansion).
"If we assume a hypothetical picture of seeing the universe from 4th dimension, we will see its edge. is this edge moving outside?" There is no evidence that the universe has an 'edge'. Dauto (talk) 21:07, 23 March 2009 (UTC)[reply]
If you were to embed the universe in some 4D space, then there would be an edge - well, the whole thing would be edge, but it would still make sense to talk about it expanding into something that is outside it. General Relativity does not involve any higher dimensional space that the universe is contained in, but there are version of String Theory that do (see Brane cosmology). --Tango (talk) 22:15, 23 March 2009 (UTC)[reply]
Tango, it's not clear to me how would someone embed the universe in a 4D space when the universe itself is already 4D. Still, even if you embed the universe in a higher dimensional space it is istill improper to talk about the edge of the universe. Dauto (talk) 22:25, 23 March 2009 (UTC)[reply]
Ok, a 3+1 universe embedded in a 4+1 space. The OP was talking about just space, not spacetime, so I followed the same convention. --Tango (talk) 23:47, 23 March 2009 (UTC)[reply]
Those who claim to understand this concept often claim that the distance between objects in space expands, such as interstellar or interplanetary distance, but smaller distances, such as my meter stick, or some other measuring device, do not expand at all. This leads to the absurdity that two objects in space linked by a gossamer thread of great length would remain unaffected in their separation by the cosmic expansion, while two similar objects not linked by a gossamer thread would move apart, the hypothetical gossamer thread having a specified length but negligible tensile strength. This makes cosmic expansion a form of magic. Edison (talk) 03:07, 24 March 2009 (UTC)[reply]
It is important to understand that the cosmic expansion is governed through the Einstein GR equations that relate the behaviour of the space-time metric to the density and flux of energy and momentum. The universe has a uniforme distribution of matter on a very large scale and on that scale the expansion of the universe is uniform. But if you look closer, you will see that the universe has clumps of matter (Superclusters, Clusters, Galaxies, etc...). On those smaller scales, the space expansion is not uniforme. In fact, locally you might even have some shrinking. Inside a clump of matter that has virialised (achived an equilibrium) like galaxies, for instance, there is no space expansion (or shrinking) at all. So, the interplanetary and interstellar distances are not expanding, but the intergalactic distances are. A yardstick wouldn't expand even if it were on intergalactic space because it is an object bound by interatomic forces which govern it's size. The gossamer seems to be simple nonsense. Dauto (talk) 04:26, 24 March 2009 (UTC)[reply]
If I am in free fall orbiting the Earth, and I place two grains of sand 1 meter apart, will the space between those grains expand? I gather no because locally space does not expand? If I take more grains of sand, and place each one meter from the previous one, forming a line all the way to a distant galaxy with measurable redshift, will some of those grains move away from their previous neighbor? Such as those far away from significant concentrations of mass. Is it specifically the mass of galaxies which prevents expansion? 88.112.62.225 (talk) 06:12, 24 March 2009 (UTC)[reply]
Yes, that's correct. Within galaxy clusters the expansion has been halted by the gravitational effect of the mass within the cluster.The placement of the grains should be at rest with respect to the comoving coordinates. Dauto (talk) 01:05, 25 March 2009 (UTC)[reply]
So, there's a mated pair of Carlina Wrens that frequent my backyard, foraging together. They're quite cute. Now, I read in our article that: "They eat insects, found in leaf litter or on tree trunks; they may also eat small lizards or tree frogs. In winter, they occasionally eat seeds, berries, and other small fruits." This doesn't quite agree with my observation.
Both of them come to my feeder, in which I've got a variety of seeds and nuts, and also a container of delicious mealworms on top. The smaller member of the pair eats only mealworms, never nuts, and the larger eats only seeds and nuts, never mealworms. Sometimes the larger one will bring the smaller one a bite of peanut, and pass it between their beaks, but it just ends up getting passed back, and the smaller wren goes back for more yummy beetle larvae.
Does anyone know what's going on there? I wonder if the smaller one is the female, loading up on bugs to feed to some chicks back at home? Why is the other one (male?) an apparent vegetarian? -GTBacchus(talk) 20:51, 23 March 2009 (UTC)
They are not nearly as "nice as 1 might think. Besides monopoloizing as many nest cavities as possible (let's not even go into monogamy and cuckoldry in small birds)They also have been known to pierce the eggs of thier nieghbouring insect eaters just before thier own hatch! As an aside, just look at the bill of any bird and it will tell a great deal about how it makes a living. The Ojib word for wren translates as "little bignose", just right for probing to find protein rich insects, not so good for seeds tho? As to what your pair are upto with thier diet choice, I suspect the below to be correct but I can't know for sure. I'm not a wren, i'm a FROG. 67.193.179.241 (talk) 12:38, 24 March 2009 (UTC) Rana sylvatica.[reply]
Could the female be preggers ? And does that alter their diets like in human women (to provide nutrients needed to grow the offspring) ? StuRat (talk) 21:19, 23 March 2009 (UTC)[reply]
Given the season, that makes a bit of sense. I'm not actually sure which one is female, or whether peanuts or bugs make better food for pregnant wrens. -GTBacchus(talk)21:26, 23 March 2009 (UTC)[reply]
It could just be that your feeder is the easiest food source and the wrens are taking advantage of it. If your feeder contained lizards and insects, it would be spot on! Livewireo (talk) 15:38, 24 March 2009 (UTC)[reply]
Wolves, dogs and foxes
Wolves, dogs and foxes are all of the same family (canine) and give birth to cubs, pups and kits (respectively). Lions and bears also have cubs (but are not of the same family as the aforementioned canines nor of each other - not to mention that the latter adults are boars and sows but not related to pigs). Seals have pups (but are not related to canines). Where is the logic in how offspring are named? —Preceding unsigned comment added by 69.77.185.91 (talk) 21:51, 23 March 2009 (UTC)[reply]
As far as I am aware, there is no logic to it whatsoever. Even less logical are the names for groups of a certain animal. --Tango (talk) 22:07, 23 March 2009 (UTC)[reply]
For a 300 foot high windmill, how big would the turbines be? I need to know how much carbon fiber material would be needed to make them. <(^_^)> Pokegeek42 (talk) 22:18, 23 March 2009 (UTC)[reply]
I think you need to try other research methods for this project than asking us everything... I'm sure the rough technical specs for some wind turbines are available online - try Google. --Tango (talk) 22:21, 23 March 2009 (UTC)[reply]
My search engines suck-all they give me is porn. My group members don't help either, they just claim their computers had a "virus" and nothing worked. I have no life anyway-this is the only human interaction I get. Mostly I ask you because I'm lonely. Seriously, do you think a total nerd has many friends? I read manga in japanese, for crying out loud. Cut me a break. I need some social time. When I'm not playing video games or reading manga or watching anime...actually, I don't do anything besides that. God, I need a life. <(^_^)> Pokegeek42 (talk) 22:29, 23 March 2009 (UTC)[reply]
Try googling for "wind turbine specs", I don't you'll just much porn from that (give or take Rule 34!). I'm sorry to hear that you are lonely - there are plenty of people that share your manga and anime obsession, why don't you see if you can find a local anime society where you can meet up with people and watch anime together? (Such societies certainly exist at most universities, I expect you can find them in the real world as well - although I warn you, the kind of people that are members are often pretty... um... intense.) --Tango (talk) 23:44, 23 March 2009 (UTC)[reply]
I'm always surprised at Wikipedia meetups by how normal everyone is. I've never heard anyone describe an AnimeSoc member as "normal"! --Tango (talk) 00:37, 24 March 2009 (UTC)[reply]
I wish I could join something like that, but I'm too "young" in my mom's opinion. I haven't finished sixth grade yet. If I joined something like that, my parents would think I'm like, totally emo and trying to commit suicide. Can you say "paranoid"? Thanks for the help, anyway. <(^_^)> Pokegeek42 (talk) 19:16, 24 March 2009 (UTC)[reply]
The good news is that considering your age, you will probably not be expected to provide an in depth stress analysis using finite-element methods. 65.121.141.34 (talk) 20:39, 24 March 2009 (UTC)[reply]
Once you dissolved the resultant gases in water, you would regenerate the ammonium and nitrate ions, which would just give you a solution of ammonium nitrate back again. What you would need to do is to have some way to seperate the nitrogen oxides from the ammonia gas in the gas phase before dissolving them into water individually. --Jayron32.talk.contribs00:36, 24 March 2009 (UTC)[reply]
I can't find any information on dystonia affecting the lower back. Does it not exist? Is it extremely rare?
Also, are there any muscles in the lower back which, upon contraction or spasm, cause the body to hunch forward? From what I've been able to find out, bending forward is caused by contraction of the abdominal muscles only and the back muscles maintain an upright posture or arch the back.
I have no answer to the first part of your post. Our page for dystonia is not very clear and repetitive in parts (two times "general dystonia" for example). For the second part: It is impossible for muscles in the lower back to cause a forward movement of the body. Muscles are always long when relaxed and "shorten" when they tense. So back muscles work to shorten the back and abdominal muscles contract the abdomen. So both muscle groups work together (called antagonistic muscles) to determine body posture and to perform controlled movements. TheMaster17 (talk) 10:41, 24 March 2009 (UTC)[reply]
Thanks for confirming the info about the back muscles, that's what I thought. I would guess then, that IF dystonia of the lower back does exist, the sufferer would NEVER hunch forward at the time of a spasm? (edit: what is causing me some confusion on this is that I recall, several years ago, pulling a muscle in my neck which caused my head to stay stuck tilted and twisted to one side. I was told that it was the muscle on the opposite side (the elongated one) that was injured, not the one on the side to which my head was sticking. So, while it definitely makes more sense to me that dystonia of the back could not cause a forward bending posture, my experience with my neck reminds me that the body doesn't always seem to work in the most immediately logical way. Or maybe the doc who told me that about my neck was wrong and it was the muscle on the shortened side of my neck that was strained?) bcatt (talk) 16:03, 24 March 2009 (UTC)[reply]
Fingerprints
Why is it widely believed that everyone has different fingerprints? It's not beyond the realms of possibility that two people who are distant and unknown to each other could have the same prints. JCI (talk) 02:12, 24 March 2009 (UTC)[reply]
Francis Galton showed back in the 19th-century that statistically the odds of two people having identical prints is pretty much impossible. This is part of what made fingerprints acceptable evidence to courts. I'm fairly sure you are more likely to have 17 matching snippets of DNA (or whatever the standard matching SNP number is) than a full set of identical prints. --98.217.14.211 (talk) 02:47, 24 March 2009 (UTC)[reply]
But, of course, the problem comes in when comparing fingerprints (especially partials) to a database containing millions. With that many to choose from, you're sure to find several fairly close matches. But, when used properly, say by comparing bloody fingerprints at the scene with the prime suspect's, then the chances of getting a false match are extremely low. StuRat (talk) 05:21, 24 March 2009 (UTC)[reply]
What Galton calculated (the calculation was not a proof in the mathematical sense, more an informed estimate like the Drake equation) was the probability of two different prints matching in all their minutiae (Finger Prints, 1892, Ch. VII). There are tens of thousands of minutiae in one print. Fingerprint analysts, however, do not compare all of them. In fact, the number of minutiae legally required for a match is in the low tens, typically (Criminalistics, James Girard, p149). So Galton's huge probabilities, even if they are correct, tell us absolutely nothing about the reliability of modern practice. --Heron (talk) 23:35, 24 March 2009 (UTC)[reply]
It depends on what you mean by "identical" - if you take two objects that are intended to be identical (two pennies for example) - they aren't REALLY identical, each has little nicks and scratches that distinguish it from the other. You can't imagine making any pair of physical objects that were utterly identical in every way. In that regard, I would maintain there are NO pairs of objects of any kind (at the 'macro-scale' at least) that are identical. Sure, you can talk about two Hydrogen atoms being identical - but not anything of any size.
So this oft-repeated claim that no two fingerprints are identical is OBVIOUSLY true at some scale of examination. There are something like 1020 atoms in your finger - it's clearly impossible that all of the atoms in someone else's finger are arranged precisely the same way. But it's not a particularly interesting or useful claim since no two of ANYTHING are utterly the same.
However, there aren't that many patterns of loops and whorls out there - there simply can't be. So at some other scale of description (perhaps a layman who knows nothing of fingerprint analysis using nothing but naked-eye examination) there are clearly pairs of fingerprints that are so similar that we'd need an expert to tell them apart. So I regard this whole thing with a deal of skepticism. Francis Galton's "calculations" cannot possibly be correct - there is simply not a solid point at which you can say "sufficiently identical to count" without very carefully defining you means of measurement and the errors inherent in making those measurements. Remember that your fingertips get cut and damaged - they grow callused if you work with certain tools - they are continually renewed and regrown. They change over time as our fingers grow from little baby fingers into adulthood. They get wrinkled up when you get them wet...so my fingerprint today is not the same as it was yesterday - at some level of examination.
The measure that I think is worth examining is whether your fingerprint at (say) age 5 years is more similar to your fingerprint at (say) age 75 years than to any one else's fingerprint in the world. I think that's a much harder standard to meet and I'd be very surprised if that were true.
It's on, Steve Baker!! You say "However, there aren't that many patterns of loops and whorls out there - there simply can't be". how much informatino entropy does a fingerprint OBSERVATION (for comparison with other fingerprints) contain? answer THAT question. 79.122.44.240 User ID added by Sifaka
What exactly do you mean by "information entropy"? Steve is right in saying that there are relatively common patterns in fingerprints, see Fingerprint#Classifying fingerprints to see what I mean. According to this paper there are more errors when comparing two fingerprints from the same finger but decades apart than two fingerprints from the same finger taken recently using a minutiae based recognition approach. A quote from the aforementioned article:
"From a theoretical point of view it is common sense that aging may not impact the characteristics of fingerprints [l]. However for practical purposes, scaling effects of minutiae based matching algorithms may render older templates useless... In most cases, the ageing process does not change the structure of the fingerprint image. The ridges in the epidermis (dead dry skin) always show the same pattern since the information thereof is stored in the lower layer of the finger (dermis - live skin). If an injury of only the upper skin is sustained, after a certain time the same ridges are formed as before. Even the ageing process cannot change the paths of the ridges. The fingerprint may be a little larger, the ridges may be lower (if they were worn due to working), and the finger may show some wounds. However, the pattern always remains the same. Therefore, it should not be difficult, for the different verification algorithms, to identify fingerprints of the same finger, which only differ in the date of their acquisition, as being identical."Sifakatalk18:28, 24 March 2009 (UTC)[reply]
The reason I addressed Steve Baker is that he is the only one here who knows what information entropy (Shannon entropy) is and can apply it to fingerprint observations!! But hes too squeemish to do so apparently...
Fingerprint evidence has been used in countless court cases. But there never seems to has been two persons found to have identical prints - not even for one finger, let alone all 10 fingers. If matching prints had ever been found, the occurrence would have received a lot of publicity. Also, from then on every defense lawyer would have fingerprint evidence thrown out. Even identical twins do not have matching prints, although their DNA is identical. Of course, matching prints of different people would have to be stumbled on by chance - fingerprint classification and searching is far from perfect. But with all the criminal cases that have used prints, two persons with the same fingerprint would surely have been found by chance. The problem with prints is that there is no known way to digitize the pattern. If there was, a computer could easily find identical prints. (Threshold scoring with a computer is useful when comparing two known fingerprints, but that is not a random search.) Illustrating this, a friend of mine had his place burgled and the burglar cut himself on the glass of the window he broke to get in, and he left a bloody fingerprint. The police said they could not try to match the print unless my friend could name 10 persons whose prints (if on file) could be checked for a match. That shows there is no way to make a full search of all fingerprints. (The FBI has a database of over 51 million prints.) Even when a match for the same person is found by other means, it is occasionally wrong due to police sloppiness (wrong name on the fingerprint card, etc.). See "Criticism" and "Errors in identification or processing" in the Wikepedia article Fingerprint.– GlowWorm.
The FBI has recently made false positive identification of an innocent person, Brandon Mayfield, as a terrorist bomber. Duplicate fingerprints or malfeasance? The proof of validity of fingerprint identification is generally lacking and is based mainly on hand-waving and unverified statistical assertions. Any forensic technique's validity should hold regardless of whether the government is out to get the individual. Edison (talk) 04:45, 25 March 2009 (UTC)[reply]
Renal Medullary Carcinoma (we don't have an article on this yet -- Done!) is a rare type of cancer that affects the kidney. It tends to be aggressive, difficult to treat, and is often metastatic at the time of diagnosis. It is not the same thing as sickle cell disease but the references in PubMed suggest that most individuals with this type of cancer have sickle cell trait or sometimes sickle cell disease -- meaning that the sickle cell trait may be a risk factor for this type of cancer (although it is still incredibly rare in people who carry the trait). See this for one of the first reports. There are also reviews available (here and here). I hope this helps. Clearly, anyone who has potential concerns about this disorder should see their physician as soon as possible. --- Medical geneticist (talk) 04:48, 24 March 2009 (UTC)[reply]
If humans manage, through war, climate change or any other mechanism, to cause our own extinction, then is it likely that some other sentient creature (not necessarily of a currently existing species, not necessarily originating on Earth, and potentially including the Creator if one exists who isn't already omniscient) will study our mistakes and learn from them? If so, does our capacity to serve as an example in this way increase with our peak population? NeonMerlin10:17, 24 March 2009 (UTC)[reply]
Given the openness of the scenario - yes clearly if some creature capable of study came about after the end of humanity then provided they can uncover a history of our demise they could use it as an aid to preventing their own demise. Of course knowing what causes something and avoiding that occuring are two different things. I don't see how a larger population makes it more obvious - apart from perhaps an increased chance of their being 'evidence' of our existence perhaps...but then i'd say a small population of technologically advanced citizens are more likely to be 'findable' than a mass-population without technological advancement. 194.221.133.226 (talk) 10:25, 24 March 2009 (UTC)[reply]
Well, given the difficulty of interplanetary travel - it's unlikely that aliens would come here. Doubly so if there were no intelligent lifeforms left here. So I think that's really highly unlikely. Another possibility might be that without humans, some other species that could survive whatever we screw up might evolve to eventually reach our levels of intelligence, curiosity and creativity. They might well be able to use archeological approaches to discover who we were and how we screwed up. Sadly, the most enduring things we'll have left behind are things like non-biodegradable plastic waste in landfills and nuclear waste bunkers - which won't speak well of our good sides. What's sad is that it's unlikely that our crowning achievements will survive - art, music, Wikipedia, architecture - all of that will have crumbled to nothing within half a million years...and it would probably take at least that for a race of intelligent cockroach-descendents to take over. I would hope that whatever fate befalls us - we'd have time to consider our legacy and build something so enduring that future species would be able to understand us. SteveBaker (talk) 11:00, 24 March 2009 (UTC)[reply]
NB: My reason for asking these questions is that if the answer is yes, then they add a positive component (which I've heretofore neglected) to, respectively, the total utilitarian value of humanity and the marginal utilitarian value of each new human born. Possibly even enough to shift the sign of these quantities from negative to positive. NeonMerlin11:06, 24 March 2009 (UTC)[reply]
That entirely depends on what you are measuring. This "utilitarian value" thing is nebulous at best and downright nonsense at worst! In order to define a "value" you have to know what you are measuring and why it's important? The universe doesn't give a damn what happens to us or what we do. This is merely a matter of philosophy - and this is the Science desk - not the standing-around-making-specious-arguments-while-being-a-waste-of-quarks desk. SteveBaker (talk) 11:32, 24 March 2009 (UTC)[reply]
In numerous science fiction works, humans have found ancient alien civilizations somewhere in the universe which had flaws leading to their own destruction. Us learning from their mistakes was a plot element, but was never a very convincing one. See also the poem Ozymandias. It would seem to be within our present technology to leave behind a better archive than the crumbling statue of Ozymandias, or some nonbiodegradable plastic bottles in a landfill and some nuclear waste casks. Take some durable substrate and archive a copy of Wikipedia, various great books, copies of world-class art and music, and park it on a space probe at the L3 point or on the moon, where it will be out of harms way for a few million years. Something like that was done on the Voyager space probe, by means of the Voyager Golden Record. Edison (talk) 13:49, 24 March 2009 (UTC)[reply]
We might ourselves be able to go pick up Voyager in a few years when faster space travel is possible. However, a new species which would evolve millions (if from chimps) or billions of years later would have a lot farther to go, since it's headed out into space, and wouldn't know where to look. If there are plastics that last forever, why can't we use them to record Wikipedia, etc. ? If no inks last that long, we could burn letters into plastic pages. Perhaps we could also make something like a DVD out of it, although that would be inherently more difficult for a future species to read, requiring that they create a DVD player. StuRat (talk) 14:22, 24 March 2009 (UTC)[reply]
If we kill ourselves through climate change and leave proof of it, than any new species that comes along will have proof that anthropic climate change can kill you, so they won't cause it. If we kill ourselves through nuclear war, it will a) give proof that nuclear war will kill you, which we know and thus must not prevent us from causing it, and b) tell them how to make nuclear bombs. By the way, this reminds me of a demotivator. — DanielLC15:07, 24 March 2009 (UTC)[reply]
(EC) Your question is very broad and has 2 very different main components. Aliens visiting our planet by definition have made it off their own dust ball. If our demise was due to the fact that we failed to establish a sustainable population elsewhere, they'd not be likely to make that mistake. (Said aliens presumable visiting our now empty world for that very purpose.) Local species would need time to evolve. Animals that are closest to us in the "use of tools" and "problem solving" department (e.g. chimpanzee, parrots) have only small populations left and it is doubtful that they will be able to multiply fast enough to become a dominant species. Animals with large populations (e.g. cockroaches, rats) will need time to evolve. By the time they get to a point of evaluating past events, there is likely to be very little left. They might dig up our "religious temple to energy" and start a traveling exhibit with our nuclear waste. Warning signs tend to be ignored, because risk taking is part of the process of developing s.th. new. (For example: Warnings on the walls of the pyramids were not paid much attention to.) Plastic will get crumbly after about 50 years, give or take. [23] It may make it for a couple of centuries under ideal conditions. Archiving Wikipedia in a durable manner would either require a consecutive population to produce backups on emerging technology or some advancement in data storage. Just consider what you'd do if you found a modern computer and a stack of punch cards, some magnetic tapes or a stack of floppy disks? ...and that would have been from within just a couple of decades. The magnetic storage will probably be unreadable anyway. CDs will merely last for about 5 years. Inscribing data in a crystal is still only a neat trick in the lab. History tells us that a) even things designed for the ages aren't necessarilyintelligible to others and b) very few blunders get avoided the second time around. (aka. History is repeating itself.) Taking what is left behind for a following civilization as the only measure for an individual's worth is a pretty measly standard. Usually his/her contribution to the species while it's still around and to it's future existence and well being might be better gauge. ("If you are going downhill, at least enjoy the ride." :-) 76.97.245.5 (talk) 16:20, 24 March 2009 (UTC)[reply]
Increasing population takes almost no time at all, when compared to the millions or billions of years it takes for new species to evolve. If a population can double every generation, which isn't that difficult in ideal conditions, that would mean it would increase 1000-fold in 10 generations, a million-fold in 20, and a billion-fold in 30. Given a 20 year time frame for each generation, that would only take 600 years. StuRat (talk) 17:33, 24 March 2009 (UTC)[reply]
600 years would indeed be under ideal conditions. It took humans considerably longer to make it from caveman to computers. Tool use and problem solving abilities help to reduce some population pressures, but by no means all. Natural selection is a lot more complex and messy than the simplified "survival of the fittest." Sometimes the fittest get their heads bashed in by the second fittest or they just can't get a prom date :-). One lowly pathogen can wipe out populations in entire areas, so simple mathematical progression doesn't quite apply. 76.97.245.5 (talk) 22:31, 24 March 2009 (UTC)[reply]
Modern humans (Homo sapiens sapiens) are only 200,000 years old, so our population increased from almost nothing to several billion in that time. While much longer than 600 years, that's still nothing compared to how long it would take another species to evolve on Earth to the same level of intelligence as we currently have. Even starting from chimps, which are 98% of the way there, it would still take millions of years. StuRat (talk) 23:57, 24 March 2009 (UTC)[reply]
So given the timescale for another species to evolve to replace us - and assuming it's not chimps or dolphins because they'll probably die right along with us when whatever befalls us comes - we'd probably have to find a way to preserve our Wikipedia backup for a billion years. Sadly, it's not just a matter of finding a good material to write it on. We couldn't count on avoiding vulcanism, earthquakes, continental subduction, rising sea levels, rock deposition, being ground to dust by a kilometer of ice in an ice age...one of those could bury our best efforts beyond the ability of any advanced race to find it. Putting it somewhere more quiet like the moon or one of the Lagrange points would make sense - but remember: that time-capsule that the super-intelligent race of dinosaurs left for us it still sitting in a crater somewhere and the backup copies at the two lagrange points are still there. So even at our level of development - there is no certainty that we'd find these information sources. If you are a pessimist - you might successfully argue that the time it takes a new species to find a carefully preserved archive could easily exceed the typical lifetime of a civilisation. SteveBaker (talk) 01:27, 25 March 2009 (UTC)[reply]
There's another good reason to leave that stuff at the Lagrange points, because when we get there we may find them cluttered with time capsules from all the previous civilizations. :-) StuRat (talk) 05:19, 25 March 2009 (UTC)[reply]
In my attic are boxes of punchcards, reels of magnetic tape,and floppy discs. There is also punched paper tape with a Fortran 2 program for a PDP-8. I have no doubt that all would be readable. Edison (talk) 04:42, 25 March 2009 (UTC)[reply]
How long do CDs last? I have some that are nearly 15 years old that work well, so I know its more then 5 years, but would they last centuries in a place like a bank vault? 65.121.141.34 (talk) 20:34, 24 March 2009 (UTC)[reply]
Plastics degrade rapidly when exposed to UV light, but I imagine they'd last far longer if buried. You'd probably also want to keep ground water away from them and bury them below the frost/freeze line. Hermetically sealed, under ideal conditions, I'd guess centuries, at least. StuRat (talk) 20:41, 24 March 2009 (UTC)[reply]
It depends very much on the specifics. In general, commercially stamped CDs last longer than writable media. But some early batches used an unsuitable glue, with CDs deteriorating after a few years only. --Stephan Schulz (talk) 20:47, 24 March 2009 (UTC)[reply]
I bought three CD's from the Philips Research Labs staff shop - about 2 months before the first CD players went on sale to the general public. All three still play just fine (In case you care - they are: Dire Straits: Brothers in Arms, Some Bach Fugues and a recording of Glenn Miller taken from the original pre-magnetic tape wire-recordings and remastered especially for CD). Those must be close to being the oldest mass-produced CD's in existence. There have been a few snafu's with disk manufacturers over the years - so some disks have behaved badly - but on the whole, they do pretty good. There is certainly no obvious fixed lifespan that you could point to. They don't all die after X number of years. (Mind you - I bet they are all three on about their tenth replacement jewel cases!) SteveBaker (talk) 01:08, 25 March 2009 (UTC)[reply]
There was a court case somewhere (EU?). The industry representatives were unwilling to guarantee their CDs for more than 5 years. So that's how long they think they'll last. That is for ones subjected to ordinary use, though. Under some carefully managed storage conditions they might last as long as the plastic stays intact. 76.97.245.5 (talk) 02:42, 25 March 2009 (UTC)[reply]
I have CD's from 1982, reel-to reel tapes from the 1960's, LPs from 1950, 78's from 1909, and cylinders from the 1890's which still play fine. It is a matter of preservation. Edison (talk) 04:37, 25 March 2009 (UTC)[reply]
There was one period where the formulation of the aluminium that's evaporated onto the disk to make the mirror-surface wasn't quite right - and CD's from many manufacturers over a period of several years had a tendency to develop tiny pin-holes in the aluminium layer - and (weirdly) an effect similar to surface tension in liquids was making the holes grow slowly over time - eventually ruining the disks. But once the problem was known, it was fairly quickly rectified - a lot of the bad press that CD's have had over the years can be attributed to that incident. SteveBaker (talk) 05:26, 25 March 2009 (UTC)[reply]
Fungus can also be a problem for CDs in some tropical countries, I've experience it personally and there are widrespread reports on the internet. It seems to eat the aluminium layer. See [24] as an example image. Nil Einne (talk) 11:17, 25 March 2009 (UTC)[reply]
As noted above, the commercially stamped media is generally far more durable than user writable CDs. The same chemistry the makes most writable CDs able to be encoded by laser heating also makes them degrade over time. I remember seeing a report that most writable CDs developed significant errors in under 5 years. This was even true of the CDs that had never been burned, they also became unusable after only a few years of shelf-life. That said, there are also some companies now that will sell you "archival quality" writable CDs. I have no idea if they really do the job, but I have heard of one company that even offers a 100 year guarantee which at least says they are serious. Of course, their product is also like $5 / disk as opposed to $0.25 for the cheap stuff that dies after a few years. Dragons flight (talk) 06:13, 25 March 2009 (UTC)[reply]
The only place that fingernail growth occurs is at the base. The entire hard part of the 'nail' is non-living; the nail extends as new material is deposited by the nail matrix: living soft tissue that sits under the nail. The visible portion of the nail matrix is the lunula, that whitish semicircular bit at the base of the nail. (The lunula may not be visible on all your fingers and toes, and it is often most conspicuous at the base of the thumbnail.) TenOfAllTrades(talk) 15:58, 24 March 2009 (UTC)[reply]
What's the hottest a human can stand for more than a few seconds?
the question on actually experiencing boiling water weeks back brough to my mind a story - don't recall where, but my money's on it being James Bond - where the bad guy locks the protagonist in a sauna or somesuch and knobs it up to about 165 degrees or so.
My question is, how much can the human body stand for more than a few seconds? I imagine the writer did some research on how high to have that turned up (why would one have the option to have it dangeruosly high, anyway?), but ISTR someone saying a really hot sauna can get up to 212 F, which is boiling? Is that really doable?
It makes me wonder about people near a blast furnace, too, where I imagine as you get real close it can be what, several hundred degrees? Or just what firefighters face, ignoring the problem of smoke.172.130.27.46 (talk) 15:44, 24 March 2009 (UTC)[reply]
This depends heavily on what the hot thing in question is. Hot metal, hot water and hot air of the same temperature will have different effects, due to differing thermal conductivity and heat capacity. A human can easily stand hot air at well above boiling temperature (try sticking your hand in an oven sometime), but boiling water is another matter. Algebraist15:50, 24 March 2009 (UTC)[reply]
Real Finland style saunas routinely go up to 100℃, and sometimes reach 110℃, significantly above the boiling point of water. People can stand this with low humidity for several to many minutes - the body manages to regulate its temperature fairly well for short periods of time. On the other hand, long-term exposure to 45℃ is very unhealthy, as is, of course, exposure to hot water quite a bit below boiling point. --Stephan Schulz (talk) 15:54, 24 March 2009 (UTC)[reply]
The key factor is humidity. In low humidity (such as the saunas Stephan mentions), the human body can cool itself very effectively through sweat even at temperatures significantly above the boiling point of water. In high humidity, sweat doesn't work, and you get into trouble at temperatures well below the boiling point of water - 50℃ will have you suffering severe heat stroke pretty quickly in tropical humidities if you aren't careful (and probably even if you are careful - without access to some form of refrigeration, at least an cool box full of ice, I can't see what you could do to survive more than a couple of hours, if that). --Tango (talk) 18:49, 24 March 2009 (UTC)[reply]
I remember reading in the Guinness Book of Records in the 1980s that humans had experienced temperatures of over 500 deg C in US Army trials and survived! Unfortunately the GBWR website is not at all search-friendly so I can't instantly confirm this. --TammyMoet (talk) 19:04, 24 March 2009 (UTC)[reply]
The melting point of Aluminium is 660.32°C, so not far off. I agree that 500°F is far more likely (that's 260°C - still rather toasty!). --Tango (talk) 20:45, 24 March 2009 (UTC)[reply]
Thanks; yeah, I thought of looking at Guinness, but yeah, their site isn't too easy to move around in? Wow, 500 degrees F is still amazing. the stuff on how much of a different humidity makes is really helpful, too. I'd have thought something that high would do something really bad to the blood or skin or somethingg even after a couple seconds; just like I've read putting one's hand in liquid nitrogen (or is that oxygen) freezes it instantly. (Then again, that's a liquid, but at that low a temperature, I think you'd get frostbite anyway.).209.244.187.155 (talk) 21:42, 24 March 2009 (UTC)[reply]
So my recollection is a little different. The way I remember it, they were NASA experiments rather than Army. The numbers I recall were that you could tolerate 400 F unclothed or 500 F if bundled up (at those temperatures a heavy jacket keeps you cool, relatively speaking). I don't know what the time frame was; I can't believe it was a really long time but presumably it was long enough to accomplish some task, or maybe make it through re-entry and have the ship pick up a living person rather than some barbecue. --Trovatore (talk) 21:59, 24 March 2009 (UTC)[reply]
There is a big difference between liquid nitrogen and air - liquid nitrogen conducts heat far better than air. If your skin ever got to 100 degrees, you would be in serious trouble within a fraction of a second, but heat doesn't go from air to skin very quickly so the body's cooling methods can prevent the skin ever getting hot enough to burn even when in direct contact with 200 degree air. --Tango (talk) 22:17, 24 March 2009 (UTC)[reply]
Putting your hand in liquid nitrogen doesn't freeze it instantly, anyway. It's perfectly possible to dip your hand in for a brief period without taking any harm (be very careful if doing this at home!). Algebraist00:38, 25 March 2009 (UTC)[reply]
Having had my face briefly immersed in a large propane flame (probably around 1000°F), walking through a turbocharged diesel exhaust plume from a military vehicle (about 400°F), and having inadvertantly swallowed drops of splashing liquid nitrogen, I can attest personally that you neither burn nor freeze instantly. My eybrows and eyelashes got singed, but otherwise I was unharmed. With the nitrogen, I was also unharmed. Frostbite can happen after a few seconds of liquid nitrogen exposure but for the most part it evaporates so fast it never directly contacts the skin (swallowing a drop results in belching out a white cloud of vapor a few seconds later). I highly recommend not trying any of this yourself. In my case, they were accidents. ~Amatulić (talk) 01:07, 25 March 2009 (UTC)[reply]
Kind of continued from this thread. Do we know whether space is expanding all over the universe (i.e. all space around us is stretching) or whether it's just the outermost sections of our universe expanding? I mean is the space around us now, Earth, the Moon, expanding with the rest of space around the universe? I'm not even sure if this is testable or not, because if all space around us was expanding at the same rate as everything else, then it wouldn't be detectable. —Cyclonenim (talk · contribs · email) 18:41, 24 March 2009 (UTC)[reply]
The expansion of space on a local scale would be detectable (at least theoretically). We measure the distance to the moon, for example, by bouncing laser beams off mirrors left by Apollo astronauts and timing how long it takes for them to get back. The speed of light isn't changed by metric expansion, so we would notice the time taken increasing (actually, the moon is moving away from the Earth due to tidal forces, but that's irrelevant!). Gravitationally bound systems (anything on the scale of galaxy clusters or smaller) aren't expanding. That doesn't mean it is just "outermost" sections of the universe expanding (whatever that means - there is no centre to be far away from) - expansion happens on large scales, but not small scales. Any two objects a large enough distance apart will be moving away from each other, regardless of where they are in the universe. --Tango (talk) 18:57, 24 March 2009 (UTC)[reply]
It sure seems like there's an influx of "expansion of space" questions lately. Anyway, this is answered in the lede of the metric expansion of space article linked in the first answer of the above question: no, small-scale gravitationally-bound systems (including the Earth-Moon system and the solar system, but also including the Milky Way as a whole and yet larger systems) do not expand within themselves. As for detectability, the "measuring distance in a metric space" subsection addresses this.
However, along a related line, it's possible that all space (and other related constants) expand at a particular rate, shared equally, and that it's therefore completely undetectable. Of course, it's also completely irrelevant -- if everything continues to function in such fashion as if there were no inexplicable immeasurable force, then we might as well assume that there is not. — Lomn18:59, 24 March 2009 (UTC)[reply]
How would you define such an expansion? Our definition of "distance" depends on various constants, and the units we express those constants in depends on our definition of distance. I can't see how you could define things in a way that makes the kind of expansion you describe make any sense. --Tango (talk) 20:35, 24 March 2009 (UTC)[reply]
I don't know how it would work, either -- I'm just noting that while such a philosophical concept could be bantered about, it's not a meaningful discussion. I've seen a few thought experiments before along the lines of "what if everything is expanding, all means of reference included?" and thought it worth addressing why they're not really interesting. — Lomn20:54, 24 March 2009 (UTC)[reply]
Hmm... as I understand it, a simple answer to your question doesn't exist: there is no universal "rate of expansion". We suspect that much of the universe is, due to expansion, now beyond our light horizon. As such, it is unknowable to us (save that it has receded at a rate greater than c). Within the observable universe, the rate of recession varies object to object; however, scientists currently believe the general trend (the deceleration parameter) is that those rates are increasing. — Lomn19:21, 24 March 2009 (UTC)[reply]
Locally, things can't travel faster than the speed of light, but on cosmological scales it doesn't quite work like that - you can think of it as the galaxies staying still and space being created inbetween them (BenRG will tell us this isn't the case, but I'm still not convinced!). --Tango (talk) 00:30, 25 March 2009 (UTC)[reply]
I realize, but space is, at least locally, homogenous, so shouldn't the observed values be the same everywhere in our observable universe? I know that most scientists believe that the rates are increasing; I am looking for the exparimentally measured redshifts that back this up. *Max* (talk) 20:12, 24 March 2009 (UTC)[reply]
There is a universal rate of expansion (or large enough scales), it's just proportional to separation. See Hubble's law. It is theorised that Hubble's Constant varies over time (increasing due to dark energy, decreasing due to gravity - observations suggest more of the former than the latter, so a net increase). I can't find any estimates of its value at other times than now, though, sorry. --Tango (talk) 20:30, 24 March 2009 (UTC)[reply]
Looking at earth from near another star, how bright would it seem? Brighter than the sun? One of the brightest things in the sky? I would like to ignore the time delay caused by the speed of light and assume that the radio brightness in 2009 is what is observed. 78.146.178.204 (talk) 23:01, 24 March 2009 (UTC)[reply]
The only terrestrial signals likely to be detectable from another star are those intentionally sent into space - either specific attempts at signalling to aliens, or from studies of planets and asteroids using radar. Those could only be detected if they were pointed directly at the star in question. So, from virtually all stars, the Earth would not be visible in the radio spectrum. If one of these radar signals happened to go to the star, I'm not sure how bright it would be - it would, obviously, depend on how far away it was, but I'm not even sure how it would compare to the Sun... --Tango (talk) 23:32, 24 March 2009 (UTC)[reply]
Using our current technology, detecting an Earth-sized planet with a level of technology similar to ours (i.e. looking at "earth from another star") would be impossible on any level, and at any frequency, visible or radio or any other. Earth is just too small. Nearly every extrasolar planet we have found has been basically a Jupiter-sized planet orbiting at rediculously close distances; such planets cause their parent stars to "wobble" and also "dim" as they pass in front of it. From a distance of a few light-years or more (remember the closest star to us is about 4 light years away) Earth would be entirely undetectable. Looking for the Earth would be like trying to resolve a specific grain of sand on a beach if viewing the beach from the moon. We are REALLY small, and we just don't give off enough general radiation to be detectable, and we don't reflect enough light, block enough of the sun's light, or gravitationally effect the sun enough to be seen. MAYBE an outside-of-the-solar-system viewer could detect Jupiter, but not earth. Possibly, if we were beaming a tight, high energy radio signal directly at another star, it could be detected, but otherwise we would be invisible. --Jayron32.talk.contribs01:41, 25 March 2009 (UTC)[reply]
I seem to recall that there have been at least two signals intentionally sent into space from radio telescopes which would have made the Earth far brighter than the sun. I strongly question the wisdom of such efforts to call attention to us. Edison (talk) 04:28, 25 March 2009 (UTC)[reply]
I'm picturing a tentacled, drooling alien creature noticing the radio emissions from Earth, then heading our way as he straps on a bib... :-)
Well - if he's that hungry, he may be in a lot of trouble because getting here is (in all likelyhood) going to take a couple of centuries. SteveBaker (talk) 05:20, 25 March 2009 (UTC)[reply]
Yes - that's true - the actual amount of power in those transmissions isn't really that great - but being sent from a radio telescope means that the beam is highly directional...I forget which stars they were aimed at - but only beings orbiting around those stars would have any chance of seeing the signal. For the rest of the universe, the earth would still have been pretty much invisible. There are other people claiming to do this though - there used to be (and maybe still is) a company on the web someplace that'll beam any short ASCII message you care to give them out in some direction or other for just a few bucks. Aleksandr Leonidovich Zaitsev[25] has been sending all sorts of things out on a really powerful narrow-beam transmitter. So this does happen...but the odds of anyone out there picking it up are really slim. SteveBaker (talk) 05:20, 25 March 2009 (UTC)[reply]
If you add up the power of all the radio, tv, and other radio-wave type emmissions (including those from power lines or electrical wiring, even thunderstorms) it must be a lot. Either it gets absorbed, or it leaks into space. I'm wondering how this would compare with the power of similar wavelengths from the sun - if these emmissions from modern technology would be a beacon in some wavelengths. 89.243.177.130 (talk) 11:39, 25 March 2009 (UTC)[reply]
March 25
Radioactive sickness?
I am writing a research report on radioactive sickness. But when I search on Google I also get radiation sickness in my resaults. Is radioactive sickness and radiation sickness the same thing? —Preceding unsigned comment added by 174.6.144.211 (talk) 00:59, 25 March 2009 (UTC)[reply]
I got a topic on Aleksandr Litvinenko's poisoning and was asked to write a report on radioactive poisoning, as this is what happened to him. But, as i mentioned before, i am not sure whether or not radioactive poisoning and radiation poisoning is the same thing, sine they both pop up when i search for radioactive poisoning. —Preceding unsigned comment added by 174.6.144.211 (talk) 01:12, 25 March 2009 (UTC)[reply]
Litvinenko died of radiation poisoning. I think whoever it was that said "radioactive poisoning" just make a mistake. --Tango (talk) 01:27, 25 March 2009 (UTC)[reply]
All these phrases are talking about the same thing, but "radiation sickness" is the proper name for it. It's not really a kind of poisoning, although people talk of it that way. (Poisons injure the body in different ways than radiation does.) --Anonymous, 01:32 UTC, March 25, 2009.
(after multiple edit conflicts) We have an article on this incident, Alexander Litvinenko poisoning. The name for what he died from is radiation poisoning. It is surmised that this was caused by the ingestion of a radioactive substance, rather than from exposure to an external source of radiation. One could call it "radioactive poisoning" in that he was poisoned by a radioactive substance as opposed to a toxic chemical such as cyanide or a neurotoxin of some sort. However, there is no real difference between what killed him and what killed the victims of the Chernobyl disaster; the only distinction is the means by which he was exposed to the lethal dose of ionizing radiation. - EronTalk01:34, 25 March 2009 (UTC)[reply]
Yes, it does. It doesn't matter where the radiation comes from or how it gets to your tissues, the effect is still called radiation poisoning/sickness. --Tango (talk) 01:55, 25 March 2009 (UTC)[reply]
Yes - my earlier response may have added some confusion here. I was speculating as to why someone might call what happened to Litvinenko "radioactive poisoning" - I didn't mean to infer any difference between internal and external sources of radiation. - EronTalk02:26, 25 March 2009 (UTC)[reply]
No. Radiation poisoning (not "radioactive poisoning" - that is not the proper name for it) is caused by exposure to high levels of ionizing radiation. There is no genetic component to it. - EronTalk02:28, 25 March 2009 (UTC)[reply]
Does nuclear warfare, nuclear reactors, radioactive materials and gamma rays cause radiation poisoning because they realease ionizing radiation? —Preceding unsigned comment added by 174.6.144.211 (talk) 02:36, 25 March 2009 (UTC)[reply]
I wrote a good chunk of the Alexander Litvinenko poisoning article - it's an amazing story, the closest thing to a classic Hollywood spy story you'll ever see in real life. But what was significant here is that Polonium-210 (which is the radioactive material that was mixed into Litvinenko's tea - and which eventually killed him) - is not normally particularly dangerous stuff. In fact, you can buy significant quantities of it in anti-static lens cleaning equipment from any decent camera store. It's radioactive - but only emits alpha radiation - which is stopped by a single sheet of paper. Even if you get Polonium-210 directly on your skin - the layer of dead skin cells that covers your body is quite enough to stop the radiation from harming you. What's dangerous is only if you eat (or in this case, drink) the stuff (or perhaps breathe it in as a fine dust in large enough quantities). That spreads it throughout your body and gives the alpha radiation a way to irradiate living tissue. I suspect that is the reason why everyone calls it a 'poisoning' - it's not at all like standing a foot away from a chunk of plutonium and getting irradiated. It only took a couple of days for Litvinenko to show symptoms bad enough to put him in hospital - but it was close to three weeks until he eventually died. For the majority of that time, it was thought that he had been poisoned with non-radioactive Thallium - because although his symptoms were classic symptoms of radiation sickness (nausea, hair falling out, that kind of thing) - there was no measurable radiation coming from his body. So they looked for more conventional poisons that produce that set of symptoms, and thallium popped up. But again - this is probably why the term "poisoning" was initially kicked around and kinda stuck - even after it was realised that this wasn't strictly a poison. The thing that's particularly chilling about this is that the murderer could have used any of a dozen - much easier to obtain - poisons in Litvinenko's tea. This one is so unique and trivially easy to trace (it has to be made in a nuclear reactor - and there are only two sources of it - one Russian and another American - but the isotope ratios make it abundantly clear that this is batch is Russian - and that it was made very soon before the poisoning took place (suggesting that the stuff hadn't been smuggled through long, complicated chains of black-market dealers). The Russians aren't stupid - they'd have known that this particular technique for killing him would be instantly traceable back to them. So it's clear that the point of the exercise was to send a message: "You aren't safe from us anywhere - and we don't care that anyone out there knows that we do this kind of thing."...that's real cold-war stuff! What we don't know is who, specifically, this rather gruesome message was intended for...whoever that is - is evidently keeping a much lower profile! Anyway - enjoy reading the article - and be sure to follow the links to the 150 or so references at the bottom - there is much more to be learned here! SteveBaker (talk) 05:03, 25 March 2009 (UTC)[reply]
In Flight Pitch Control / Dive or Stall
Can someone with knowledge of the principles of flight help me understand something? A UK company named Parajet is building a flying car of sorts called the SkyCar. At the link the above, they make the following statement about the SkyCar:
"It has no pitch control and therefore (is) impossible to stall or dive."
So what is it about having pitch control in fight that makes stalling or diving possible? Why would its absence prevent these situations? Appreciate any input. Wolfgangus (talk) 01:23, 25 March 2009 (UTC)[reply]
"Pitch control" means being able to control what angle the nose is at in a vertical direction. Obviously, that is required to dive - diving is pointing to nose steeply downwards. Stalling is caused by trying to climb too steeply (or not descending fast enough if you're going quite slowly). Presumably this flying car sets its own pitch, somehow, at a level somewhere below where it would stall. (I guess you then control altitude by varying speed - slow down to go down, speed up to go up. However, that would mean it must be possible to either stall, or dive - if you cut the engines, one of those two things has to happen.)--Tango (talk) 01:32, 25 March 2009 (UTC)[reply]
I imagine they just mean it is possible for you to cause a dive or stall by applying too much upward or downward pitch. --Anonymous, 21:35 UTC, March 25, 2009.
Actually, I take my last statement back - cutting the engines wouldn't be sufficient, you would probably need some way to actually brake to get slow enough for the only non-stalling configuration to be a dive. --Tango (talk) 01:36, 25 March 2009 (UTC)[reply]
What stalls a plane is when the pitch of the wing to the airflow is too steep. If you pitch the plane up and have plenty of engine power - the plane climbs and the airflow remaines pretty much parallel to the wing....but if you pitch the plane up without enough power applied - you get into a vicious circle where the wing loses lift - you start to fall downwards - which means that the airflow is now somewhat upwards - which further increases the angle of pitch to the airflow - which increases the drag - which slows you down - and the pitch angle to the airflow increases still further - until you're simply falling like a rock. What's suspicious about this claim is that even without pitch control - if you slow the motor down enough then the roughly 4 degrees of upward pitch (which you pretty much have to have built into the wing to make the plane fly) - is enough to cause a low-speed stall. The way you recover from such a stall is to push the nose down and (if you can) you apply power. Without pitch control - if your engine fails - you've got no means to recover from the stall and you're going to crash.
There is a means to fix this problem - and that's to have a 'canard' design - where the pitch control happens on surfaces in front of the main wing and with a slightly steeper pitch than the main wing. What happens then is that if your speed drops, the little 'canard' wings stall before the main wing can - when the front wings stall - they lose lift - the nose falls - and that automatically reduces the angle of attack - so they immediately un-stall without any input from the pilot. Of course if you lose the motor - the plane is going to nose down into the ground...but it won't stall - so you stand at least a chance of pulling out of the dive when you've built up enough speed.
The other odd thing about not having pitch control is that you can't fly faster or slower...if you add power without altering your pitch - you'll climb - and if you reduce power without changing pitch - you'll lose altitude. At a particular pitch there is only exactly one speed that'll keep you flying level! I find it hard to believe that this contraption really doesn't have some means to control pitch - I imagine that what they REALLY mean is that the pilot has no direct control over pitch - it's hard to believe that the flight computer can't control pitch.
I definitely agree with Steve here, the only reasonable explanation is that the pilot has no direct control over pitch. There must be a mechanism for pitch control for the airplane to be flyable. If there were no pitch control, a steady altitude could only be maintained at one speed, which would be a complex function of weight, center of gravity, and air density. It would even change during flight as fuel is consumed, or even if a passenger leans forward in their seat! In turbulent air natural stability would be the only way to maintain attitude (and therefore altitude). It's even possible that in turbulence near the ground, the aircraft could be put into an attitude where recovery with no pitch control is impossible. Finally, pitch control would be necessary to flare into the proper attitude for landing. So pitch control is basically required for any airplane, even if the pilot has no direct control. anonymous649403:43, 25 March 2009 (UTC)[reply]
Thanks so much for the solid feedback, and that's right- a powered parachute, although the term - the entire field actually - is new to me. There are clearly some pretty substantial differences between this vehicle and the Terrafugia Transition but I was assigned to write a feature about the SkyCar and was told it was a flying car plain and simple. Evidently that's not the case at all. Wolfgangus (talk) 06:57, 25 March 2009 (UTC)[reply]
Mount st Helens
hi,
i think i heard somewhere that when mt st helens erupted in 1980 that it released more corbon dioxide into the atmosphere than humans have done to date. Is this at all true or not?
Please do your own homework.
most libationious of ways, maybe russians or something more viscous next. ;-) -hydnjo (talk) 02:38, 23 March 2009 (UTC)
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