Wikipedia:Reference desk/Archives/Science/2006 July 12

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sepsis[edit]

what is the simple explanation about sepsis of newborn?

i have a case study...and I am asking for a good reference about my topic...

Please remember that the Reference Desk is manned by volunteers who visit in their free time. Patience is appreciated and there is no need to ask a question more than once. Try searching Wikipedia for sepsis, and return here if you have more specific questions. --Ginkgo100 talk · contribs 02:35, 12 July 2006 (UTC)[reply]
I always cringe when I hear "Reference Desk volunteers". I'm pretty certain most of the people here aren't volunteering their time, but rather have nowhere better to go, though that's just semantic ; ).  freshofftheufoΓΛĿЌ  03:12, 12 July 2006 (UTC)[reply]
No, it's just offensive. You should think hard about making such an inflammatory statement. If you have such a low opinion of the people who bother to answer questions, or of Wikipedia itself, maybe you should extend your "long distance relationship" with the site to somewhere like Alpha Centauri. JackofOz 04:01, 12 July 2006 (UTC)[reply]
I agree with JackofOz; Freshgavin, that's rather rude. In the first place, engaging in an activity one enjoys does not preclude it from being volunteering. In the second place, while I cannot speak for others, my life is certainly busy and I have other things to do, but the idea of contributing to human knowledge appeals to me and I will gladly sacrifice some time when I can to write articles, answer questions, and assist in the functioning of the community, because I think it's a good cause. — Knowledge Seeker 04:21, 12 July 2006 (UTC)[reply]
There was a smiley. It was a joke. I found it funny. Folks need to calm down a bit. —Bradley 04:42, 12 July 2006 (UTC)[reply]
The meaning of a communication is the response it elicits. (Anyway, it's 2 against 1. So there.) JackofOz 04:56, 12 July 2006 (UTC)[reply]
2 on 2. if someone's that sensitive about something, its probably because its close to the truth... Xcomradex 05:00, 12 July 2006 (UTC)[reply]
I have little tolerance for incivility or disparaging other editors anywhere on Wikipedia. Furthermore, I don't understand what the purpose of your statement is. Are you implying that I was lying about how busy I am? Perhaps I go on extended Wikibreaks and such just for show? The danger of Freshgavin's comment is not of course its impact on me; it doesn't really matter whether other Wikipedia editors realize my coolness or not. It is important, though, that visitors to the Reference Desk, especially those who aren't regular visitors, realize that contributors here volunteer their time out of goodwill, and that one should maintain the appropriate respect and gratitude to those who are helping one out without any expectation of a return favor. — Knowledge Seeker 05:19, 12 July 2006 (UTC)[reply]
I apologize if I have offended you, and you are right to lash back at my comment. I didn't mean to imply that people weren't volunteering their time, and with a little more thought it is evident that many people on Wikipedia selflessly give a large amount of their time to activities in a manner very similar to volunteering, with noble and humble intentions. When I hear the word "volunteer", it conjures up images of my experiences volunteering, many of them containing acts of a much less "noble" and "humble" nature, which is I guess why I have tried to avoid using the word before now. My apologies.  freshofftheufoΓΛĿЌ  05:30, 12 July 2006 (UTC)[reply]
Accepted. No hard feelings, Freshgavin. JackofOz 06:02, 12 July 2006 (UTC)[reply]
Wow. I never knew that such an obvious joke could elicit so many angry responses. --Bowlhover 04:28, 13 July 2006 (UTC)[reply]
What's obvious is not always obvious. JackofOz 05:36, 14 July 2006 (UTC)[reply]

Artificial gravity[edit]

Another question based on an assumption: Assuming increasing gravity is a piece of cake, what would happen if the gravity of the moon were increased to equal that of the Earth? For the purposes of the question, I'll imagine that an object of incredibly high gravitational attraction is inserted into the center of the moon. Would the surface of the moon experience any structural change? Is there any theory to suggest that the moon doesn't have to smash into the Earth (due to it's suddenly increased mass or percieved mass)?  freshofftheufoΓΛĿЌ  03:45, 12 July 2006 (UTC)[reply]

I am not certain about the effect on the moon's surface, but but if the mass of the moon were suddenly increased in such a manner, its current orbit would certainly become quite unstable. Unless the momentum of the earth or the moon were otherwise modified, it seems certain that the two bodies would collide. Depending on how quickly the moon's mass were increased, the resulting effect on Earth could be devastating to civilization as well, even before the collision. — Knowledge Seeker 04:30, 12 July 2006 (UTC)[reply]
I suppose that the size of the moon would reduce. Then the earth and moon would come closer, due to increased gravity. Then the orbits of both earth and moon would change. May be there is a possibility of Earth and Moon orbiting each other like a pair of binary stars --Wikicheng 12:06, 12 July 2006 (UTC)[reply]
Don't forget that with increased gravity, the moon must have increased mass, which gives it more inertia. So, it would go into a much wider orbit as it takes more gravitational pull between the Earth and moon to bend its path. --Kainaw (talk) 12:52, 12 July 2006 (UTC)[reply]
It depends on what momentum the added mass has when you add it. Since we know of no way to just "magically" change something's mass, we don't actually know what would happen if one did. If we want to be scientific, we have to stick to known-possible things like dropping rocks on (or into the core of) the moon, and then we have to ask whether they're all falling on one side or so. If the rocks were put at the Moon's orbital velocity before being added, the orbit wouldn't change because it would be just like the new rocks orbiting independently. --Tardis 14:26, 12 July 2006 (UTC)[reply]
That would increase the current mass of the moon by a factor of 81 (current mass: 0.0123 Earth masses). Even if the orbit remained unchanged, this would increase the tidal effects of the moon on Earth, which would be quite severe, I would think. I'm not sure how to quantify how the effects would manifest, however. Ocean tides would certainly be increased, but I do not know to what degree. I would expect earthquakes as well. —Bradley 16:14, 12 July 2006 (UTC)[reply]
Tidal sands on the moon would be cool.  freshofftheufoΓΛĿЌ  04:10, 13 July 2006 (UTC)[reply]

You're asking us to apply the laws of physics in a situation where they have been violated. Interresting that someone named 'Tardis' came up with this first. :) DirkvdM 08:21, 14 July 2006 (UTC)[reply]

Think of Gravity as a force that push's away the moon and the moon pushing away the earth. Its not the size of the moon but it weight. The weight of the push,that keep's it away. Like a rock on a string going around and around, the force is not an attraction it is a pushing away. With out this pushing away the moon and the earth would be one.

Both would orbit around a central point. Philc TECI 23:26, 16 July 2006 (UTC)[reply]

Which species?[edit]

I took these pictures yesterday in southern Ontario, Canada:

http://72.136.70.187/IMG_3963.JPG

http://72.136.70.187/IMG_3981_increased_brightness_and_contrast.JPG

http://72.136.70.187/IMG_4006.JPG

(You can go to http://72.136.70.187/toads_original to view the full-sized photos.)

Can someone please identify what species these two toads belong to? Thanks! --Bowlhover 07:18, 12 July 2006 (UTC)[reply]

I would guess that it's just an American toad. I'm not convinced there's another Bufo in Ontario. --Aranae 04:47, 21 July 2006 (UTC)[reply]

password to folder[edit]

Hi I know that you add passwords to a folder using a compressed folder, now I installed winRAR. Can anyone direct me the exact instructions of setting a password to a folder? Thanks

Depends on your operating system. Try variations of this search. Weregerbil 10:22, 12 July 2006 (UTC)[reply]

Seeing Sun & Moon together[edit]

I would like to know why on some days we can see both the sun and the moon in the sky? Does this mean that the people on the opposite side of the earth cannot see either? Is that then new moon for them? If it makes any difference, I am in Knysna on the south coast of South Africa.

Thanks so much.

--Guppythane 08:04, 12 July 2006 (UTC)[reply]

  • You can see them because they are both there...well.... some people think that the moon is only in the sky at night, but that's just wrong. You just notice it more at night. Many nights have no moon (and yes, when you don't see the moon (and the sky is clear), people on the other side of the world probably can).
Each month, the moon goes right round the sky. When the moon is full, it is opposite the sun, and you can't see both at the same time. As the moon turns into a crescent shape it is getting closer to the sun. Finally, there is a "new moon" and the moon is very close to the sun and cannot be seen. Then it starts to get further away. Scientists can predict where the moon will be on a given day, even in hundreds of years time. Notinasnaid 08:15, 12 July 2006 (UTC)[reply]
  • If you are able to see both the sun and the moon during the day, people on the other side of the world can't see the moon not because it is new moon for them but because the moon has not risen for them yet. For example, if you are seeing a waning gibbous moon in the morning sky, it is also a waning gibbous for those on the other side of the earth, they just won't be able to see it for a few more hours until it rises above their horizon.
P.S.: "(and yes, when you don't see the moon (and the sky is clear), people on the other side of the world probably can)." This is true unless it is a new moon. If that is the case, nobody can see the moon no matter where they are in the world unless there happens to be a solar eclipse in progress in which case one can see the moon passing in front of the sun. --Nebular110 18:54, 12 July 2006 (UTC)[reply]
The moon rises and sets just like the sun. Its cycle is not 24 hours, so it is not tied to the sun's cycle. In fact, it repeats the cycle every 29.5 days. Sometimes it is up at the same time as the sun; sometimes it is up while the sun is not. What is tied to the sun as well as the lunar cycle is the phase of the moon. When the lunar cycle has the moon rising at the same time as the sun, you can't see the moon at all, and it is termed a new moon. New moons are therefore never at night (although you won't see the moon at night during a new moon because it hasn't risen). Likewise, full moons are always at night. Half moons either rise during the day and set at night, or rise at night and set during the day, depending on whether they are waxing or waning.
Question: Does anyone know how many times the moon rises and sets during a cycle? --Ginkgo100 talk · contribs · e@ 19:41, 12 July 2006 (UTC)[reply]

Rainforests produce Oxygen?[edit]

What are the scientific evidence that Rainforests, as an ecosystem, produce a surplus of oxygen? --DelftUser 13:00, 12 July 2006 (UTC)[reply]

What do you mean, surplus? More oxygen than they use? How do they use oxygen? (Notwithstanding the oxygen used when they're burned down by farmers, lol).--Anchoress 13:49, 12 July 2006 (UTC)[reply]
Respiration and decomposition. Trees die. For an area to be a net source of oxygen (= net carbon sink) it either tree growth has to exceed death (common in young forests), or carbon has to be accumulating in the soil (again, common in young forests, also in wetlands. Soil carbon stocks in the tropics is uncertain, probably higher in the seasonal tropics than the ever-wet tropics. Deep soil carbon and highly recalcitrent carbon (stuff that decomposes very slowly because it's not attractive to microbes) is the big deal. Guettarda 13:58, 12 July 2006 (UTC)[reply]
(after edit conflict)
Your question is good. It means you've realized that as a tree gets larger and larger, the amount of surplus oxygen it produces decreases. Most people incorrectly believe that the larger the tree, the more surplus oxygen it creates. This has little to do with carbon dioxide consumption (the larger the tree, the more it consumes). I would love to find a graph that shows average tree size and average oxygen production. But, getting to your question, the quote I see all the time is that 40% of oxygen comes from rain forests, 20% comes from the Amazon alone. With those percentages, perhaps you can google the source of them. --Kainaw (talk) 13:52, 12 July 2006 (UTC)[reply]
[ec]
Jean Pierre H. B. Ometto, Antonio D. Nobre, Humberto R. Rocha, Paulo Artaxo & Luiz A. Martinelli. 2005. Amazonia and the modern carbon cycle: lessons learned. Oecologia 143: 483–500
The difference calculated from these two methods would imply a local sink of approximately 1.6–1.7 Pg C year�1, or a source of 0.85 ton C ha-1 year-1. Using our crude extrapolation of LBA values for the Amazon forests (5 million km2) we estimate a range for the C flux in the region of -3.0 to 0.75 Pg C year�1up>-1.
In other words, counting deforestation and carbon sequestration, the Brazilian Amazon is either a source of sink of carbon; if it's a carbon sink, it's a net source of oxygen, if it's a carbon source, it's a net sink of oxygen. Guettarda 13:54, 12 July 2006 (UTC)[reply]
Can you explain why if it is a carbon sink, it is a net source of oxygen? Is not possible for an ecosystem to be a carbon sink and an oxygen sink? I am very skeptical that 20% of produced oxygen results from the Amazon forest! does that number takes into account the oxygen used in the Amazon?! If all other sources of oxygen in the world would be eliminated, and all consumers also, except the Amazon would there be more oxygen after a year or less?? --DelftUser 14:12, 12 July 2006 (UTC)[reply]
[ec]What they are saying is that they found conflicting results based on different methods of estimation, and that their best estimate is that the true value is somewhere between being a moderately large sink (3 Pg per year) and a relately small source (0.75 Pg per year) of carbon (mostly due to deforestion). So the answer to your question is "maybe". On the other hand, saying that 20% of oxygen is produced by the Amazon is a totally different question, because that is a question about gross oxygen production, not net. Guettarda 14:25, 12 July 2006 (UTC)[reply]
That is exactly what I want: net oxygen produced by a rainforest as an ecosystem! I like to dispute the idea that Rainforests are important for human survival, some environmentalists like to claim that they produce oxygen and I just wanted to check so next time I can show them that what they say is wrong! --DelftUser 14:30, 12 July 2006 (UTC)[reply]
Well no, it wouldn't be accurate to say that. While the idea of rainforests as "the lungs of the world" is oversold, it isn't wrong. To say that the estimate is between -3 and + 0.75 suggests that it is a net source (the mean of that estimate would be negative; assuming it is symmetrical, it would be around -2). This is the most recent (and broadest scale) study I can find - there are earlier studies (based on increases in aboveground biomass in the eastern Amazon) which suggest significant carbon uptake by living biomass. It's one of the problems that this study was unable to reconcile - the difference between estimates in carbon uptake based on eddy covariance (estimating the fluxes of carbon and oxygen across a stand of forest) and measures of standing biomass. The other side of this, of course, is that it includes carbon output by deforestation. If someone speaks about the importance of rainforests for human survival, they are talking about the forests as forests, not the forests being destroyed by deforestation.
The other point of this is that the oxygen concentration in the air is a dynamic process - without plants to replace it, oxygen would continue to be consumed by decomposition and reactions with minerals. It's a very reactive compound. In addition you have to think about the trees as standing stocks of carbon, and forest soil as an even bigger stock of carbon. There is a difference between digging up the forest (and its soil) and shipping it off-planet and the common way of removing forest, which is cutting, burning, and converting to pasture or cropland - which continue to be major carbon sources for decades as the carbon stocks are decomposed away. So your friends are right, even if it is potentially for the wrong reasons. Guettarda 14:50, 12 July 2006 (UTC)[reply]
If they are right then where is the scientific evidence for it! The study you cite above is about carbon and not oxygen, I am aware that oxygen in the atmosphere needs replenishing but I am convinced that it is done by phytoplankton, Algae and other plants in the ocean and not by rainforests! I suspect that rainforests consume all they produce, if not more. --DelftUser 14:58, 12 July 2006 (UTC)[reply]
I'm not sure what you mean by "where is the scientific evidence for it". The article I referenced provides just that. Carbon is fixed through photosynthesis, which releases oxygen. (see photosnthesis) Basic reaction of photosynthesis is: 6 CO2 + 12 H2O + ATP + NADPH → C6H12O6 + 6 O2 + 6 H2O - you have one molecule of oxygen released for evey molecule of carbon fixed. An oxygen molecule weighs about 2.5 as much as a carbon atom. Aerobic respiration consumes one molecule of oxygen for every atom of carbon released, C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy released (2830 kJ mol−1). Anaerobic respiration can release carbon without consuming oxygen, so equating carbon fluxes with oxygen fluxes is necessarily conservative.
The range provided by the paper suggest that Brazilian Amazonian forests are a net producer of oxygen. The mean of the estimate is around -2 Pg of carbon, which would equal +4.5 Pg of oxygen. Their estimate also includes an estimates 0.10–0.40 Pg C year-1 released through deforestation, logging and forest fires (which are, in this system, human-caused). It isn't enough to conclusively say that the Brazilian Amazon is a net source of oxygen, but that's a (marginally) more reasonable conclusion than saying that it uses as much or more oxygen than it produces. In addition, this study is conservative. Most previous studies have estimated that the Brazilian Amazon to be a net carbon sink (= net carbon source).
In addition, you said "I like to dispute the idea that Rainforests are important for human survival". If you want to look at it that way, then even if they are a net oxygen sink, they are still important because the alternative is a huge oxygen sink. If you argument is based on oxygen and carbon for human survival, you need to look at the full budget. Guettarda 16:02, 12 July 2006 (UTC)[reply]
I suppose you meant "net carbon sink = net oxygen source". DirkvdM 08:48, 14 July 2006 (UTC)[reply]
Please remember that the question is about the ecosystem and not just the trees! rainforests are full of animals who burn oxygen; so the question now: is the net sum of the total rainforest positive or negative? Until now I haven't seen any scientific evidence that it is positive. On the question of human survival please note that I don't consider CO2 (in the atmosphere) as a polutant, nor global warming as an environmental problem but natural change that human beings should (and will) adapt to. --DelftUser 17:54, 12 July 2006 (UTC)[reply]
PS: I found the article you've cited I'll read and see if it answers my question, thanks! --DelftUser 18:00, 12 July 2006 (UTC)[reply]

As shown in this [1] all the carbon in the earth was here from the beginning. The only real carbon sink is in the formation of carbon sediments. We can create a temporary carbon sink by creating more lumber, either in houses or trees. We liberate net carbon by burning sediments. Even over a small cycle of a thousand years, natural processes have fiddled with the carbon cycle a lot more than we have. The other cycle that is just as important to the climate is the free-water cycle, which again has varied tremendously over the larger time scale. --Zeizmic 14:19, 12 July 2006 (UTC)[reply]

It all depends on whether you are talking about historical or geological time scales. Pretty much all the free oxygen in the atmosphere is produced by photosynthesis. Vegetation cover changes with climate change, and while the carbon held in living biomass is a "temporary" sink, forests exist for thousands of years. Even if a large proportion of the carbon turns over on a decadal time scale, the fact that there are trees there for thousands of years means that the forest (but not the individual tree) exists as a carbon sink on a millenial time scale. Charcoal produced by burning biomass is stable even on a geological time scale (I know someone who studies Cretaceous fossils which are simply charred plant bits). Carbon in sediments also enters through biological processes (be it as calcium carbonate or organic carbon). Recalcitrant soil carbon turns over on a millenial time scale as well. So it's really an oversimplification (to the point of being wrong, basically) to sat that the only "real" carbon sink is carbon sediments. Guettarda 14:35, 12 July 2006 (UTC)[reply]

A simplification, but not wrong. A 'sink' is something that increases carbon storage over time, like a drain. If a forest is increasing it's lumber storage over time, and no forest fires, then it is a sink (but doesn't exist!). Most forests are dynamically stable. If the black soil organics are increasing over time then it is a sink, like an active Dinosaur swamp, but those are sediments. --Zeizmic 17:13, 12 July 2006 (UTC)[reply]

Delftuser, you make it clear that you first draw your conclusions and then want to find the reasons to support. Not a very scientific approach. DirkvdM 08:48, 14 July 2006 (UTC)[reply]

I am willing to listen if you have something to say! Do you? Anyway I found what I was looking for: “It is estimated that algae produce about 73 to 87 percent of the net global production of oxygen” (from the algae article). --DelftUser 20:37, 15 July 2006 (UTC)[reply]

The trees are made of carbon compunds, thats all the evidence you need surely, as it got the carbon from CO2 therefore leaving o2. Philc TECI 23:29, 16 July 2006 (UTC)[reply]

I don't think you even understand what we are discussing here! --DelftUser 19:35, 17 July 2006 (UTC)[reply]

Old Rifles[edit]

I've read the articles on rifles and British rifles, but I can't quite figure out the answer to this. During the Peninsular War, what kind of rifles did the British army use, if any? Also, what kind of bullet, and how were they loaded? What range? I've been rewatching old Sharpe episodes, and I wonder whether they're anywhere near accurate. Black Carrot 14:50, 12 July 2006 (UTC)[reply]

The Baker rifle was in limited use along with the more common Brown Bess musket. Rmhermen 22:36, 12 July 2006 (UTC)[reply]

Algal bloom[edit]

Hi folks. The post about the Amazon got me thinking - I have heard from a few places an idea put forth by some global warming researchers, and I was wondering about what y'all think about the pros and cons. Basically, the idea is to dump huge tankerloads of nutrients into the oceans to encourage a gigantic bloom of algae or zooplankton, which would trigger a huge wave of photosynthesis and a dramatic drop in CO2 levels in the atmosphere. I think the nutrient usually cited is iron - perhaps that is a common limiting nutrient in algae growth? This strikes me as both rather brilliant and incredibly foolhardy and dangerous, and i can't decide if it is more stupid or brilliant. Care to comment? --Bmk 17:22, 12 July 2006 (UTC)[reply]

The process is called iron fertilization (a thorough article that you should find helpful). --Ed (Edgar181) 18:55, 12 July 2006 (UTC)[reply]
Thanks! That certainly hits the nail on the head --Bmk 19:19, 12 July 2006 (UTC)[reply]

botany[edit]

why do the trunks of some trees twist? i don't think this can be due to climatic conditions as i have witnessed it deep in a forest. is it physiological and does the condition have a name? azu fletcher

I don't know if it has a name, and I am not a botanist, but I do have one idea. Keeping in mind that trees grow from the inside out (i.e. the tree starts as a tiny sapling and the trunk grows wider with each season), a twist in a trunk likely reflects that the sapling was twisted somehow when it was young and still twistable. It could be due to something like a second sapling growing up next to the current tree, resulting in their branches running into each other and one giving the other a bit of a twist. Just a thought... 128.197.81.223 19:10, 12 July 2006 (UTC)[reply]
It can be due to other trees or vines. It could also be that a tree that grows "deep in the forest" today used to grow in the middle of an exposed field. Have a look at thigmomorphogenesis and reaction wood. Guettarda 00:18, 13 July 2006 (UTC)[reply]
Both articles are pretty basic - you might want to try google as well. Guettarda 00:20, 13 July 2006 (UTC)[reply]

gravity[edit]

a stone falls from a ledge and takes 8 seconds to hit the ground. The stone has an original velocity of 0m/s. How tall is the ledge in meters? what formula would I use? —Preceding unsigned comment added by 198.175.175.113 (talkcontribs)

formula = g/2 * t^2
with g = 9.89 m/s^2
--DelftUser 18:02, 12 July 2006 (UTC)[reply]
We don't do homework for you... -- Миборовский 22:37, 12 July 2006 (UTC)[reply]
Isn't it 9.81 m/s^2 ? --Shanedidona 01:18, 13 July 2006 (UTC)[reply]
And what formula is that? --Shanedidona 01:21, 13 July 2006 (UTC)[reply]
Yes, the acceleration due to gravity, g, is 9.80665 m/s2. I don't know if the equation has a name, but it's basically the equation of a position of an object moving in one dimension undergoing constant acceleration, with the initial velocities and positions set equal to zero. It's an extremely common equation in physics and algebra. y''(t) = a, so y'(t) = at + C = at + v0, so y(t) = ½at2 + v0t + D = ½at2 + v0t + y0. Setting the initial velocity and height to 0 gives y(t) = ½at2. — Knowledge Seeker 02:51, 13 July 2006 (UTC)[reply]
Isn't the equation one of the Newton's Three Laws of Motion? Jayant,17 Years, Indiacontribs 11:17, 13 July 2006 (UTC)[reply]

science[edit]

when an automotive battery is fully charged the sulfric acid and water mixture will have a specific gravity of about???????? —Preceding unsigned comment added by 198.175.175.113 (talkcontribs)

Close to nothing? Gravity is an extremely weak force compared to say, EM. -- Миборовский 22:38, 12 July 2006 (UTC)[reply]
Wrong science. he means specific gravity. Xcomradex 23:00, 12 July 2006 (UTC)[reply]
at 70 deg F (damn imperial units),
    Open Circuit          Approximate           Average Cell
   Battery Voltage      State-of-charge       Specific Gravity
        12.65+               100%                  1.265+
        12.45                 75%                  1.225
        12.24                 50%                  1.190
        12.06                 25%                  1.155
        11.89                  0%                  1.120
Enjoy. Xcomradex 23:14, 12 July 2006 (UTC)[reply]
Ooops. Didn't see that. -- Миборовский 03:59, 13 July 2006 (UTC)[reply]

Speed of Light Squared[edit]

Why does the speed of light squared happen to give the conversion from matter to energy? What is special about the the speed of light? - PSB

You may find this article useful: E=mc^2 128.197.81.223 19:13, 12 July 2006 (UTC)[reply]
For one thing, it's not just the speed of light (actually it's only the speed of light in a vacuum), it's the fastest speed that makes sense, and it's a kind of conversion ratio between distance and time. In special relativity, distance and time aren't independent quantities. Imagine if we used one unit to measure length and a different unit to measure width. If you turn an object 90 degrees, the length becomes the width and the width becomes the length, so it's silly to have different units for them. In special relativity the same thing happens with distance and time. Two events could be separated in time but not in space to one observer, but to a different observer whizzing past, they are separated in space and much closer in time. The only thing that remains the same for all observers is the spacetime interval, which can be measured in units of either time or space. The speed of light in a vacuum is the conversion factor between these two representations. —Keenan Pepper 21:53, 12 July 2006 (UTC)[reply]
Right. In a very real sense, in special relativity, light goes at c because it's the conversion factor between space and time, not the other way around. And the conversion factor between space and time also appears in converting between mass and energy. -- SCZenz 22:06, 12 July 2006 (UTC)[reply]

Naproxen[edit]

Does naproxen change the effectiveness of the birth control pill?

i doubt it. a google of 'naproxen contraception' shows its recommended for pain while on contraceptives. Xcomradex 23:05, 12 July 2006 (UTC)[reply]

Norwalk Virus and kidney problems/complications?[edit]

My best friend just called me to say he's had it for the last three days and is quarantined. Thing is, he's had kidney failure in the past. He wouldn't listen to any advice I found for him anyway ;-| but can anyone fill me in on recovery time, residual effects etc? He figures he got it from fruit or vegetables at the market; I haven't seen any info on an outbreak locally, which there are sometimes in hospitals and old folks homes; are individual occurrences in the general population documented in any way?Skookum1 21:12, 12 July 2006 (UTC)[reply]

See Norwalk virus group. No mention of kidney problems associated. --Ginkgo100 talk · contribs · e@ 19:52, 13 July 2006 (UTC)[reply]

So important to have been returned[edit]

I am Taiser Aborashed.My research was appreciated from the ministry for health of syria in 2001 for Basel Assad Prize in hazards reduction, depends upon a kind of a communication that occures in accordance and continiously since 26 years and up to now,between me at my space and time and/with who are in front of me at the screen or and the microphone of the audiovisual devices which are in front of me,at my side in direct broadcast and/or transcending time. Please if you let me know if you could get me some possibility at your foundation,I would be grateful. I am sorry I could not attend the third international conference on early warning: (Removed email address EVOCATIVEINTRIGUE TALKTOME | EMAILME | IMPROVEME), as I am a participant and to contribute its outcome.

Best Regards, Taiser Aborashed

If you're looking for a job, try the "Contact Wikipedia" link in the box to your left. EVOCATIVEINTRIGUE TALKTOME | EMAILME | IMPROVEME 21:23, 12 July 2006 (UTC)[reply]
There is a position open on the Board. ---CH 22:07, 14 July 2006 (UTC)[reply]

CD picture[edit]

can you burn a picture into the information site of a CD, like Lightscribe (exept that thst this would be on the information side of the disk and wouldn't need a particular brand of drive) --Shanedidona 21:36, 12 July 2006 (UTC)[reply]

Yes, DiscT@2 can do that, however, for obvious reasons, only on areas of the data side where there is no data. — QuantumEleven 11:44, 13 July 2006 (UTC)[reply]
Do you have to use a Yamaha drive? --Shanedidona 22:38, 13 July 2006 (UTC)[reply]

optimum mph for best mpg[edit]

What would be the best speed on the interstate for a large block full size pickup and a SUV in N.E. Texas. The pickup will be driveing with tailgate up.21:50, 12 July 2006 (UTC)Thanks

This looks rather similar to another post. We would need to know the vehicle model and the exact engine, transmission gear ratios, and wheel sizes to hazard a guess. StuRat 22:54, 12 July 2006 (UTC)[reply]
Another option is to figure it out experimentally. That is, drive 55 on the highway from one fill-up to the next, then 60 the next time, then 65 another, and compare the number of gallons of fuel and elapsed mileage to get the mileage at each speed. If 60 gets the best mileage, then maybe repeat the experiment with speeds of 57, 60, and 63 to find the ideal speed more precisely. StuRat 23:01, 12 July 2006 (UTC)[reply]
That assumes linear or near-linear response with no surprising discontinuities or local minima/maxima. :-) Johntex\talk 01:35, 13 July 2006 (UTC)[reply]
Maybe the manufacturer would have information on efficiency vs. MPH. --Shanedidona 00:31, 13 July 2006 (UTC)[reply]
Odds are, you're going to get local minima at around 10-15mph, 25mph, 35mph, and 50-55mph, corresponding to first, second, third, and fourth gear. Which one is the most efficient depends on wind resistance, internal rolling resistance, road friction, and drivetrain design, but I'd bet on either 25mph or 35mph. --Serie 22:36, 13 July 2006 (UTC)[reply]

nuclear power plant[edit]

hello, i would like to know which nuclear power plant is on this picture : File:Nuclear powerplant-01.jpg. thanks


It's the Byron Nuclear Generating Station in Ogle County, Illinois. --Bmk 22:38, 12 July 2006 (UTC)[reply]
Damn you! After the long search I just did before finding it, I hit refresh and there you are! :) 128.197.81.223 22:51, 12 July 2006 (UTC)[reply]
Lol - better luck next time --Bmk 15:25, 13 July 2006 (UTC)[reply]