Wikipedia:Reference desk/Archives/Science/2007 February 5

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February 5

Planet Rotations

Why do all of the planets (and many other stellar objects) have somewhat parallel orbits around the sun? Why aren't there things orbiting the sun that are more perpendicular to the orbit of the planets? Imaninjapirate^{talk to me} 00:55, 5 February 2007 (UTC)

The prevailing theory (Planet#Formation) has the planets forming from a nebula condensing into a thin disk rotating around the proto Sun. There are things orbiting outside this narrow plane, but they're just not big things. Clarityfiend 01:06, 5 February 2007 (UTC)

When matter starts to gather up, it tends to flatten in the shape of a disc, what we call protoplanetary disc (see article for a good explanation of why this happens.) This is how solar systems form. Most of the big objects in our solar systems were formed this way, that's why they all tend to have roughly the same orbital plane and move at the same direction. Smaller objects, however, are easily disturbed and have less-stable, irregular orbits. That's why smaller moons and asteroids have highly inclined orbits and all that. — Kieff | Talk 01:19, 5 February 2007 (UTC)

The flattening of a nebula into a protoplanetary disc is simply a case of the conservation of angular momentum. It is exactly the same reason why an ice skater spins faster when they pull their arms in closer to themselves. Carcharoth 02:01, 5 February 2007 (UTC)

Correlation of events...?

Where can I find the correlation between eating a big meal followed by a heart attack? 71.100.10.48 02:41, 5 February 2007 (UTC)

This study found that:

Of the 158 patients who reported eating an unusually heavy meal during the 26 hours before their attack, 25 of them had the meal in the two hours right before the attack. Only 6 patients had their big meal in the corresponding two-hour period the previous day. By comparing the two time-slots-24 hours apart-the study controlled for the possibility that time of day, and not the meal itself, was the trigger. The remaining patients in the group of 158 had their heavy meal at various other times in the 26 hours before the heart attack, but no other time-slot emerged as significant.

Rockpocket 07:41, 5 February 2007 (UTC)

Unknown disease

Anyone know of a disease nicknamed drop(s)? --The Dark Side 02:52, 5 February 2007 (UTC)

Dropsy? —Steve Summit (talk) 02:55, 5 February 2007 (UTC)

Reversed West and East on the Moon?

Hi - I read somewhere years ago that West and East are reversed on the Earth's Moon as a result of astronomers projecting our own West and East onto it - but now I can't find references to that idea anywhere - am I looking in the wrong places, or am I totally mistaken?

Thanks Adambrowne666 03:16, 5 February 2007 (UTC)

Having a look at these two images: Western Hemisphere and Moon surface. It seems like they are not reversed. - Akamad 05:20, 5 February 2007 (UTC)

That's what I keep finding too - I've got such a strong impression of this notion, but can't find evidence of it - I wonder if it has always been the way it is now - is it possible early astronomers mapped it that way, and it has been switched since? Adambrowne666 10:49, 5 February 2007 (UTC)

It's an intersting point you make - it depends on how you define east and west - for instance does the sun always rise in the east? Is east defined by the rotation of the body? The earth and moon are separate bodies so it's difficult to say what is east on the moon??87.102.8.103 11:29, 5 February 2007 (UTC)

It is either based on the rotation of the body, or the Earth as a reference. [Mαc Δαvιs] X (How's my driving?) ❖ 14:31, 5 February 2007 (UTC)

It might have something to do with the fact that astronomical telescopes invert the image. Since reverting the image will degrade it, astronomers have gotten used the inverted images, to the point that even their drawings are inverted. This would mean that "west" is on the right. Perhaps this is what the questioner has in mind. (But before you take this to the bank, this is remembered from when I was an astronomy buff, about 35 years ago. Maybe 'scopes have changed in the meantime). Bunthorne 06:40, 6 February 2007 (UTC)

Why would reverting the image degrade it? Surely a digitally stored image could be spatially inverted in a lossless fashion. I suppose you couldn't do it with an analogue form like a photograph, as you'd have to produce a new photograph from it, which would be a copy of a copy. Maelin (Talk | Contribs) 04:09, 7 February 2007 (UTC)

Sorry, I wasn't clear. While astronomers no longer look through modern scopes (they use CCDs instead), historically (before cameras) they would look through the eyepiece directly at the image. The only way to save the image to paper was to draw it, and they drew it as they saw it. Due to the optics of the scope, the image would appear upside-down. To have it appear right-side up would require extra lenses (or an erecting prism), thus degrading the image. So for many years, it was the convention that drawings, prints, etc. would be printed upside-down, just as it would appear in the telescope.Bunthorne 07:12, 9 February 2007 (UTC)

Well, rather than inverting the image, though that's a clever thought, Bunthorne, I always assumed it was because if the astronomer is facing North as he/she looks up at the moon, then West is to the left, East is to the right, and perhaps for ease of reference, he/she then maps the West to the left side of the Moon, East to the right - so that when you're standingg on the Moon itself, you get a reversed East and West ... does that make sense? Adambrowne666 21:36, 7 February 2007 (UTC)

Yes I get that.. Though I've haven't yet found an example of a moon chart being labelled "east/west" - maybe astronomers have understood this two and avioded using east and west because of the potential for confusion? What they do use to describe degrees around the moon I have no idea - and the article moon doesn't seem to have the answer.83.100.250.165 21:41, 7 February 2007 (UTC)

If you look at this image {Image:Moon map grid showing artificial objects on moon.PNG] and compare it with the list here List of artificial objects on the Moon you'll see that west on the moon is relative to the moon - not earth - so west goes right.. not left like on our earth maps...83.100.250.165 21:48, 7 February 2007 (UTC) Wrong way round - I'm asking at Wikipedia:Reference_desk/Science#moon east

See Selenographic coordinates. --Heron 21:35, 9 February 2007 (UTC)

only eating vitamins

What would happen if I stop eating conventional food and only eat vitamins? Would I die? What if I also eat sugar? Thank you. Renaud Miclette Lamarche

From nutrition: "There are six main classes of nutrients that the body needs: carbohydrates, proteins, fats, vitamins, minerals, and water. It is important to consume these six nutrients on a daily basis to build and maintain healthy bodily function." If you take vitamins, that'd cover vitamins.

And from Sugar#Health_concerns, "The panel [at WHO] stated that the total of free sugars (all monosaccharides and disaccharides added to foods by manufacturers, cooks or consumers, plus sugars naturally present in honey, syrups and fruit juices) should not account for more than 10% of the energy-intake of a healthy diet, while carbohydrates in total should represent between 55% and 75% of the energy-intake."

So the short answer is, no. --Wirbelwindヴィルヴェルヴィント (talk) 04:02, 5 February 2007 (UTC)

YOu need some dietary fiber too. --Shantavira 08:15, 5 February 2007 (UTC)

Vitamins are part of the group called micronutrients (along with minerals), which are needed in doses of milligrams or micrograms. Vitamins are needed for the body to be able to do properly some of its functions. Macronutrients, that is lipids, carbohydrates and proteins are the bulk of our needs (doses in the order of magnitude of grams), and they provide energy. If you only ate vitamins you would be lacking almost all the daily energy intake and would become weaker and weaker in a very short time span (maybe less than 3 weeks) and with die of hunger. --Taraborn 10:10, 5 February 2007 (UTC)

You don't actually need polysaccharides, fat or protein for energy, but proteins are useful for other things instead

mitosis and meiosis

do you have any draws of meiosis and mitosis?

Meiosis and Mitosis? Splintercellguy 03:43, 5 February 2007 (UTC)

Gummy Bear Rocket

I’m having a contest with my buddies to see who can make a device that can fling/shoot/launch a gummy bear the farthest, anything goes. I seem to remember a demonstration that rocketed a bear after it (the bear) was heated. Ring any bells? Thanks --Willworkforicecream 04:55, 5 February 2007 (UTC)

You might want to see our article on Sabots. With such a device (and perhaps a railgun), I'd imagine you could impart nearly unlimited velocity to your Gummy (former) bear.

Atlant 12:48, 5 February 2007 (UTC)

I would think that in order to have a contest, the bear would have to be a projectile in its natural state, and impact with full gumminess. Otherwise, you could just pour a melted gummy into a hollow-nose bullet, and fire away! --Zeizmic 13:12, 5 February 2007 (UTC)

If anything really goes, how about sending the gummy bear by air mail to someone living on the other side of the earth? It will have flown most of the way. Or figure out some other way to get the gummy bear on an airplane.

To beat even that, you'll need a friend who works at NASA and owes you a big favor. Unfortunately, you missed your best chance by just over a year. —Ilmari Karonen (talk) 13:09, 5 February 2007 (UTC)

Today they told me that "anything goes" means anything mechanical goes, so chemical, magnetic, etc. isn't allowed any more. Wusses, they were just scared of my coilgun idea. --Willworkforicecream 19:06, 5 February 2007 (UTC)

You could build your own scale model of an aeroplane, and stick it to that

Well, if you aren't allowed any chemical or magnetic you can't use anything with an engine, I'm thinking: "What did people use to fling things far before engines and explosives and stuff?". I'd be investigating trebuchet and catapault. Vespine 21:50, 5 February 2007 (UTC)

You could try a stomp rocket or a water rocket. Theresa Knott | Taste the Korn 21:57, 5 February 2007 (UTC)

Hmm a red link! See here Theresa Knott | Taste the Korn 21:59, 5 February 2007 (UTC)

And I've turned it blue. If anyone wants to help edit our brand new stomp rocket article please feel free. Theresa Knott | Taste the Korn 22:33, 5 February 2007 (UTC)

Thanks for the ideas. I think that I'll go with a trebuchet because they're awesome. I'll blow everyone out of the water by putting the bear inside of a bouncy ball that will bounce and roll to gain extra distance. --Willworkforicecream 18:51, 6 February 2007 (UTC)

That might be an excellent idea, if the terrain downrange is such that the ball will bounce nicely on it. If the terrain was, say, loose sand, I'd suggest a (mostly) solid iron/steel ball instead: maximizing the density of the projectile minimizes the effects of atmospheric drag. In any case, you may want to experiment with balls of various sizes and materials. Denser is still better, but elasticity will count a lot too if you go for the bounce. The optimal size of the ball (for a given material) will depend on how powerful your launcher is: too big and the initial velocity will be low, too small and you'll lose speed to drag; a back-of-the-envelope calculation of the optimal mass would be a nice physics exercise, but in practice an empirical approach will probably work just as well if not better. I'd expect a fairly large superball might do well, if you can get the gummy bear inside it without ruining its bounce. —Ilmari Karonen (talk) 20:13, 6 February 2007 (UTC)

a weed pest called Wolsia or Wollsia

This pest is growing in our dam and we cannot find a way to get rid of it - the plant has been identified by the Department of Natural resourses Queensland but they have no knowledge of how to kill it Gwen Kelly

I can't find any info on those two names, I don't think you have spelt it right. If you can't find the correct name, would you be able to upload a photo here? Thanks. --liquidGhoul 12:46, 5 February 2007 (UTC)

woollsia in Ericaceae  ?87.102.8.103 18:02, 5 February 2007 (UTC)

Most pest plants aren't easy to kill - that's why they become pests - you need to find out how it can regenerate - for instance some plants can survive fire / chopping down - because they have a rhizome - the plant regenerates from the rhizome - is this is the case one way to proceed is to keep chopping it down - eventually the store of energy in the rhizome will be used up and the plant die.

You could try using a strong weedkiller - killing everything - don't forget to salt the ground as well.

An alternative is to add an even more invasive species that out grows it.

Or if you are lucky a pest that kills the plant can be found.

It's difficult to beat nature though.87.102.8.103 18:15, 5 February 2007 (UTC)

You're evil. – b_jonas 20:45, 6 February 2007 (UTC)

Han and Hong classification of inverted nipples

This classification is used by plastic surgeons to classify the three main types of inverted nipples. The Han and Hong classification is often cited in journals. I would like to know when this classification first came into effect, the first time it was published and where and also who owns the copyright to this classification. Thank you. Dharani.

Look at the last journal article in which you saw it cited-- it likely contains the reference that answers your question. alteripse 14:05, 5 February 2007 (UTC)

Hyperbolic cooling

Do the huge "hyperbolic cooling towers" seen in power stations actually utilize a section from the perfect shape of hyperboloid? If so, how close to the shape is it? And how does this system improve water cooling efficency?Wbchilds 10:15, 5 February 2007 (UTC)

I can't answer your first two questions. But the reason for the shape is one of structural integrity see Cooling_towers#Cooling_Towers_of_Nuclear_Reactors The shape is chosen for it's stabilty not to improve cooling efficiency. (Not sure if that was your question)87.102.8.103 11:36, 5 February 2007 (UTC)

Projectile Motion

I'm currently doing a prac write up for year 12 Physics. At the moment I've hit some what of a road block. I'll try to describe the problem. A projectile is fired from a table (same height as the table) at a 45° angle, the projectile lands on the ground 2.54m away. The table is 0.75m high. The speed of the projectile is unknown, the time of flight is unknown. Is it possible to work out how far away from the origin the projectile is when it comes in line with the table. Heres a diagram I drew in MS Paint to help illustrate the problem:

The green question marks indicate the value I would like to know. Oh yeah, I almost forgot, Ignore air resistance.

P.S. If anyone works this out could they please tell me how because I would also like to do this with my measurements of other angles/distances.

P.P.S. This isn't really counted as "answering my homework" because we aren't required to put this info in our prac report, I simply want to enhance it.

Yes you can. First, if you were given the initial velocity, angle (which is known), and the time after firing, can you calculate where (x,y position) the projectile is? If so, you have a known (x,y) position of the projectile at some point (the position where it hits the floor, relative the the firing position). From that you should be able to solve for the initial velocity and time after firing (2 equations with 2 unknowns). With the initial velocity and angle, you should easily be able to solve your problem. --Spoon! 12:09, 5 February 2007 (UTC)

(edit conflict) Well, ignoring air resistance, the trajectory is a parabola, which, in general, is described by the function $y(x)=ax^{2}+bx+c$, with the first derivative $y'(x)=2ax+b$. Setting the origin to the starting point on the table, we have $c=0$, and the starting angle tells us that $y'(0)=b=1$. The remaining condition is that $y(2.54)=a(2.54)^{2}+2.54=-0.75$, which can be rearranged to give $a=-(0.75+2.54)/(2.54)^{2}=-0.51$ (approximately). Solving for $y(x)=-0.51x^{2}+1x=0$ the usual way, we get $x=1/0.51=1.96$ (again approximately). Depending on how pedantic your teacher is about significant figures, you may need to round that up to $2.0$ meters (since the table height was technically given only to two significant digits), though in practice I'd consider the three-digit figure a more useful answer. Ps. If you do use these answers in your report, remember to be nice and credit the reference desk. —Ilmari Karonen (talk) 12:36, 5 February 2007 (UTC)

science in transportation

information of what science contribute in transportation. —Preceding unsigned comment added by 210.186.3.142 (talk • contribs) 14:37, 5 February 2007

I guess you mean "information from which sciences contributes to transportation (technology)." - if so the answer includes engineering primarily, computer science in modern computer controlled systems, mathematics - various models not related to engineering eg queueing theory, chemical engineering and metallurgy contribute to materials used in construction of transportaton devices, social sciences may also help in the design of public transportation systems, geography and geology relate to the way the transport network is built, meteorology is important easpecially in sea and air travel, in fact most of the common practical sciences contribute in some way.87.102.8.103 15:29, 5 February 2007 (UTC)

To measure distances on earth

I woud like to know how i can measure shortest way from a place to an other, for exsamble from boston to london.Any solution for this.

hp

If you know the latitude and longitude of the two places, and you assume the earth is spherical it's quite simple.

First calculate the angle between the two places, using the latitude and longitude (relative to the centre of the earth. If you don't know how to do this please ask about it.

Then multiply the angle(in degrees) by 2πR/360 - ie Anglex2πR/360 this is the length of an arc(geometry) which subtends an angle of A - that is the distance 'as the crow flys' - R is the radius of the earth.

If you want the absolutely shortest distance from A to B (ie though the earth's crust in a straight line the distance is 2Rsin(πA/360) 87.102.8.103 16:30, 5 February 2007 (UTC)

See the articles Great circle and Great-circle distance. The second article describes a method which uses a sphere to approximate the shape of the earth, and the article claims a maximum error of about 0.5%. The problem of finding a geodesic on an oblate spheroid is much more complex and cannot by solved analytically.

For calculating the shortest distance between two points along a straight line running beneath the surface, convert the latitude and longitude of the two points to earth centered, earth fixed coordinates:[1].—eric 16:59, 5 February 2007 (UTC)

isn't the cross section of the earth elliptical, meaning the difference from the equator streight up is proportional to the distance from a line between the poles outward

Is denatured alcohol 100% volatile as a solvent?

If I were to extract some essential oils from lavendar using denatured alcohol, would it completely evaporate (like acetone or high grade ethanol)?

typically no. If it's surgical spirit no - it leaves an oil behind. If it's purple 'meths' no it leaves a purple residue.

You should be able to get denatured alcohol that does not leave a residue (I assume to avoid having to pay tax) if you seek it out specifically - that could be ethanol with only methanol in. Find a supplier (chemical or similar - and tell them what you want)

Alternatively you could distil some other denatured alcohol to get a residue free liquid (obviously this is a potential hazard and may even require a license to do..) and the distillate may carry over some impurities.

Or it's possible to use alternatives such as propanol.87.102.8.103 17:22, 5 February 2007 (UTC)

Pissing too often

i recently switched from sitting down when i piss to standing up. all of a sudden, it seems like i need to take a leak too often. could it be because sitting down empties my bladder better or is this a sign i could have a serious male medical condition.. i dono prostate colorectal something like that? do i need to see the doctor? i dono why im asking all these questions.. shouldn't i just switch back to sitting and see if the problems stops?

There are lots of different causes of needing to piss more often - including mild infections, over injestion of diuretics (eg coffee), psychological reasons and more serious problems and diseases. As I/We can't see you and check your general health or ask about what other factors may be an issue it's really impossible to give you an good answer.

If it's a problem eg you can control your bladder (wet yourself), or are pissing many times more often than you should you should see a doctor - definately.

However if the difference in the amount of pissing you are doing is trivial - Could it be because it's easier to piss standing up that's why you go more often?

I'd recommend you go and see a doctor - and ask them about it. They usually give you a look over anyway so you should get some feedback on your general health as well as getting an answer to this problem.87.102.8.103 19:44, 5 February 2007 (UTC)

Hmm Could be diabetes. Go to see a doctor soon! —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

Dog breeds -- Help!

Why are chihuahua, poodle, pit bull, labrador retriever, and alaskan husky considered different breeds of the same species, while lions, mountain lions, tigers, jaguars and leopards considered diffirent species of cat? they seem equally unsimilar to me. our Species article says something about a species being a group of animal that can succesfully reproduce and produce fertile offspring. is it even possible for chihuahua and the large domestic dogs reproduce togeher!? if so, is that what makes them one species? and thers so many species of jackal, coyote, and wolf. why arent they lumped together? they cant interbreed?

members of a specis also have to have physiological, morphological, biochemical and behavioral similarities, but this is mostly just for taxonomy which hardly anyone uses now

This discussion cover some aspects of dog breeding. However, the major difference is that the dogs you list are domesticated, while the felines are not. And thus the generation time since the last common ancestor of the dogs is much, much shorter than the last common ancestor of the cats. The cats have become speciated, the dogs have not. Rockpocket 20:00, 5 February 2007 (UTC)

All breeds of dogs -- even a chihuahua and a great dane -- can reproduce and create fertile "hybrids". The fertility of the feline species in question is a bit more complicated, however. Also note that, for example while a coyote and a wolf can interbreed, their offspring tend to be less fit than a pure-bred and often die in the wild, whereas an interbred dog has about equal survival-ship (i.e. fitness) as a pure-bred. Check out speciation and hybridization. --Cody.Pope 07:50, 6 February 2007 (UTC)

Do you have data for the assertion "an interbred dog has about equal survival-ship (i.e. fitness) as a pure-bred"? The common held belief is that a mongrel has a greater fitness than a pure-bred, due to a reduction in inbreeding depression. While I'm sure that isn't the case all the time, I would propose that on average, first generation outbreds would be fitter than first generation inbreds, due to a reduction in homozygosity. Rockpocket 07:45, 7 February 2007 (UTC)

On that note, have a chihuahua and a great dane ever mated and produced offspring? I'd imagine the mother would have to be a great dane, as great dane puppies would probably be too big for a mother chihuahua... but then how would a male chihuahua... erm... "reach" the female great dane? And what would the offspring look like? --Candy-Panda 09:27, 6 February 2007 (UTC)

I don't know if they have done it, but usually when breeders try to mate two creatures of very different sizes, they use artificial insemination. Certainly, new cat and dog breeds are sometimes started by crossing existing breeds. Skittle 00:41, 7 February 2007 (UTC)

While I don't personally know of any actual examples of a chihuahua × great dane, if asked to bet I'd put my money on it having happened several times quite naturally. Where there's a will there's a way, after all, and dogs in heat certainly have the will. For what it's worth, I did once meet a dog that was reportedly the offspring of a (male) papillon and a (female) siberian husky. He seemed like a quite normal medium-sized dog, with somewhat fluffy fur, a distinctive bark and a strong temperament, but nothing that would've really struck me as particularly out of the ordinary. —Ilmari Karonen (talk) 14:46, 9 February 2007 (UTC)

Using digital sound recorder as decibel noise meter?

I've just bough a digital sound recorder - a Tevion Digital Voice Recorder ET-880 to be exact. It can communicate with a computer via USB. It can record in "ACPCN", "ACTPC", and possibly "WMA" sound formats. I'm wondering if I could use it as a decibel noise meter by measuring the average sound intensity when the recorded file is transferred to the computer? —Preceding unsigned comment added by 62.253.44.193 (talk • contribs) 22:16, 5 February 2007

(This answer is aimed at digital audio recorders in general, not this specific one which I only find very little information about.) I don't see how you could end up translating this into db. For one thing, whatever mic is built into the recorder is going to have certain compression characteristics. Also, the level of the sound in your digital recording is going to depend on where your level was set when you recorded, assuming the recorder lets you do this. Long story short- I think in order to measure sound pressure levels, you need a device specifically intended for this. Friday (talk) 22:34, 5 February 2007 (UTC)

You you do, do you? And what do you knoew about anything/ —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

All the same I have known professional noise pollution specialists use a calibrated mic (don't know how calibrated, don't know brand) and a high quality portable recorder (Nagra back in the analog recording days) to record ambient sound on site before a plant is built, then run it through an analyzer back at the lab to determine the dB of noise pre- and post- plant operation. If they had just stared at a meter dial and written down the dB of ambient noise before the plant was built, they could have waited until a truck went by. If someone doubts the high pre-plant noise level, they can haul out the tape and show that it was the pig farm, birds, or bullfrogs. In general mics do not compress sound in the usual sense, but they have a certain gain, like -50dB and a certain frequency curve and directionality which has to be taken into account. The trick would be having a calibrated mic with a calibrated preamp, so that a certain sound pressure level produced a certain level n the recording, then to filter the sound per the applicable Weighting filter to get dbA, for instance. See Weighting filter and decibel for more info and more links. If the desire were to use the system for litigation or environmental health legal applications, an ad-hoc system would be subject to criticism, but if it were to satisfy curiosity, you might be able to conjure up a system. Edison 00:47, 6 February 2007 (UTC)

Quality of radio reception dependent on where I stand

When I have the radio on in my room, sometimes the reception is good when I stand in a certain spot (even in a certain position) and turns crappy as soon as I move from there. How does this happen and is there a (easy) way to improve the reception? Thanks Lukas 22:32, 5 February 2007 (UTC)

Yeah dont stand where the sound is crappy —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

I think that the reason you see the effect is generally capacitance between you and the antenna. To improve reception, either stand where reception is good the whole time, or try moving the antenna higher up. anonymous6494 23:33, 5 February 2007 (UTC)

(Edit conflict) At about 3 metres, the wavelengths of broadcast FM signals are roughly the same size as you, so you can interact pretty strongly with those FM waves, diverting them around you or reflecting them. This can produce constructive or destructive interference at your radio's antenna. You may be able to reduce some of this by changing the position of the antenna (remembering that many table radios use their power cord as their antenna). In particular, if the antenna is oriented vertically (as you usually are when walking around), try orienting it horizontally.

Atlant 23:39, 5 February 2007 (UTC)

weather

What type of weather does low air pressure usually indicate?24.34.194.200 22:47, 5 February 2007 (UTC)

Stormy weather —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

See also Cyclone. – b_jonas 20:33, 6 February 2007 (UTC)

more for the poison question above

ok guys first i wanna say thanks so much for helping me understand the effects of the poisons and everything. its really grea and secondly i wanna say thanks for not sugar coating the effects!! now ok here we go as for cyinade posion. if you were to keep the heart beating and the lungs working (via CPR or another method) would it be possable to survive a normal Leathal dose of cyinade once it goes through the body (since it does so at a fast rate) ?? or will the cell damage the cyinade causes be too great to survive?? thanks again Maverick423 22:55, 5 February 2007 (UTC)

You asked a similar question recently, and the first reply had a few errors in it, I would encourage you to scroll up and see the corrections if you haven't already done so.

So as stated above, ATP is the fuel with which the cell carries out many functions. Cyanide causes death by disabling ATP synthesis, and cells and by extension the entire human organism dies as a result. ATP acts on the enzyme cytochrome C oxidase by binding to it and preventing it from performing its normal duties. Cyanide also denatures the cytochrome, preventing further use. There are drugs which help avoid interaction between the cyanide and enzyme, but you are asking whether someone could be kept alive through CPR until the cyanide has the chance to exit the cells. The answer is, unfortunately, no. Cytochrome c oxidase takes four electrons (originally from NADH produced in the TCA) and adds them to molecular oxygen, creating (with dissolved protons, or hydrogen ions) water. This powers the Cytochrome c oxidase to push four hydrogen ions into a space in which they can power the transmembrane protein that creates ATP from ADP. The entire purpose of oxygen, despite the fact that it propagates toxic molecules and is itself reactive to vital cellular structures, is to accept these electrons from cytochrome c, as mediated by the oxidase. Oxygen, that vital substance, is just an electron sink. Without cytochrome c oxidase, oxygen is useless to the human body. Since CPR is little more than an artificial method to keep the body perfused with oxygenated blood, you can see why even perfect oxygenation of cells during cyanide poisoning is useless. Also note that, since the cyanide destroys the enzyme discussed, the body would have to make new cytochrome to replace it, which requires ATP, which is not available. All medicine can do in the case of cyanide poison is prevent it from interacting with cytochrome in the first place (and other important molecules) by introducing an agent which the cyanide prefers to bind with. See methemoglobin. ^tucker/_rekcut 02:12, 6 February 2007 (UTC)

Thanks much tuckerekcut you have been very helpful in my quest for intellect. Maverick423 14:20, 6 February 2007 (UTC)

dental hygienist/therapist

Hi, I am applying for a job as a dental nurse in Scotland, hoping to progress to a hygienist/therapist. What kind of uniform would I be wearing typically, and would I use a stethoscope etc in the latter jobs?

Yours, Alan

Hello Alan. Having been to a few dentists in Scotland, my personal experience is that the nurses and hygienists tend to wear tunics like this chap. I have never seen a stethoscope being used in a dental office. Rockpocket 01:05, 6 February 2007 (UTC)

....Nor by a hygienist or therapist, though there are many different kinds of therapist, and some might have a use for a stethoscope. Stethoscope will explain what it's for.--Shantavira 08:40, 6 February 2007 (UTC)