Wikipedia:Reference desk/Archives/Science/2007 September 9

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[edit] September 9

[edit] Angioplasty vs. Thrombolytics

Which is the more effective treatment for an acute myocardial infarction - percutaneous coronary intervention or thrombolysis? Does a physician ever have to choose between the two? —Preceding unsigned comment added by John1234567890 (talk • contribs) 01:02, 9 September 2007 (UTC)

For acute MI, the most effective approach is cardiac catheterization lab assessment (which often involves recanalization of an occluded vessel). For institutions that don't have a cath lab, thrombolytics are the most appropriate secondary approach, while they send patients to a hospital with a cath lab. --David Iberri (talk) 05:05, 9 September 2007 (UTC)

[edit] Ozone cleaner

I'm having difficulty finding a device that will clean ozone out of a room. If you type "ozone" and anything remotely close to "cleaner" or "filter" into a search engine, you come up with hundreds of ozone generators. I want the exact opposite - a device that will convert the ozone in an ozone-rich room to something less hazardous, such as O2. Is there anything like that available on the open market? -- kainaw™ 01:15, 9 September 2007 (UTC)

Had a bit of an electrical problem? Hopefully you weren't tossing food in front of a microwave RADAR to warm it up! (Sorry, I have no idea how to absorb ozone; maybe you could spray some CFCs around?) Nimur 05:05, 9 September 2007 (UTC)
Incidentally, ozone specifies that the decay time of O3 to O2 in atmospheric conditions is less than a half hour. If you are still having problems with ozone / ozone smell, maybe you have a more serious problem - some other chemical hazard? Insert standard "seek professional advice" comment... Nimur 05:11, 9 September 2007 (UTC)
Potentially whatever is generating the ozone is still operating. Have you isolated the source yet? I remember I once had a defective light producing ozone but it could be anything electrical potentially. If you're unable to operate in the room because of the ozone, I would suggest you do what you would do if you have a shortcircuit. Turn off the room or house's power at the fuse box, ventilate the room and then turn off everything in the room. Turn the fuse back on and turn each device on one by one. Make sure you keep the room ventilated of course Nil Einne 09:31, 9 September 2007 (UTC)
Google remove ozone. 152.16.59.190 07:11, 9 September 2007 (UTC)
Ventilation? DirkvdM 08:01, 9 September 2007 (UTC)
Thanks. Ventilation is not an option and the source of the ozone is well known (liquid oxygen storage and a small room with over 300 power supplies sharing a closed-loop air conditioning unit). The ozone remover from the anonymous user's Google search should work well - if I can get administration to order one. Maybe I can find some OSHA regulation to force the issue. -- kainaw™ 15:28, 9 September 2007 (UTC)
As Nimur says - the stuff decays naturally in 30 minutes or so. So it won't build up indefinitely unless there is really inadequate ventilation. If the amounts you are producing is so high as to represent a health risk even with that decay rate, then I think you have something causing arcing in those power supplies and the ozone is the least of your problems. Personally, I think I'd just install some big fans and blow it out to atmosphere. It seems like it should dilute rapidly and decay before it can do any great harm. However, this is definitely one of those "Seek professional advice" things. SteveBaker 16:07, 9 September 2007 (UTC)
Some copy machine and laser printers have an ozone filter. I can't imagine how it works, though. My understanding is that you have to dilute it, or let it oxidize something. --Mdwyer 03:49, 10 September 2007 (UTC)
A catalyst to accelerate the decomposition of ozone back to molecular oxygen seems reasonable. Google for ozone decompose catalyst to see los of examples, including many that don't look like Infomercial crap. DMacks 07:07, 10 September 2007 (UTC)

Tin Oxide is used I believe. Polypipe Wrangler 11:01, 12 September 2007 (UTC)

[edit] Detection of Maltose

I need to find a way to detect the appearance of maltose, or measure the rate of hydrolysis in starch? My project includes taking corn starch with different pH values, and testing the effect of amylase at different pHes on hydrolysis. Any help appreciated. —Preceding unsigned comment added by Blooooo (talk • contribs) 02:40, 9 September 2007 (UTC)

This might be expensive, but you can use maltase and then look for glucose. ←BenB4 03:11, 9 September 2007 (UTC)
The old iodine trick should work. Iodine will turn starch blue. But I don't think it will discolour maltose. I don't quite know what the effect of pH is on the colour of Iodine though, so this might make things a bit more difficult.PvT 13:07, 9 September 2007 (UTC)
Even if there is a pH effect, you could do the test on a sample at the instant it's exposed to the conditions and compare it to one on a sample after some time. That way you're comparing two results that were under the same pH conditions (and then examine this change with respect to pH or amylase). Any time you have a variable, you need some sort of control group to see what its effect is, both on "what you're testing" as well as on the mechanism of the testing itself. DMacks 15:11, 9 September 2007 (UTC)
Thanks for the help everyone. I plan on using amylase (can't get maltase apparently) and checking the pH at every point of the expirement, before amylase, after amylase, before iodine, and after iodine and then repeating the experiment for discrepancies. Blooooo 19:57, 9 September 2007 (UTC)
You could detect the hydrolysis of starch by other means. For example, you could make some starch gels ready for electrophoresis. Do the various treatments, and then electrophorese some standard things. Check with someone who does this sort of thing. Polypipe Wrangler 11:12, 12 September 2007 (UTC)

[edit] Seeing the future

What is the chance that someone born in 1992 will live to see the year 2100? --124.254.77.148 08:48, 9 September 2007 (UTC)

  • This question obviously calls for speculation, so I'll speculate: I consider the chances to be rather low that anyone will be alive in 2100. In 1892, there was no foreseeable technology that could wipe out all of humanity. Just a half century later that was no longer the case. The democratizing nature of technology means that smaller and smaller entities become more and more powerful over time. In the beginning only the most powerful nations could build nuclear weapons; now some of the poorest in the world have them. It's easy to imagine that in the next 100 years individuals will have access to that level of destructive technology, in the form of genetic engineering, nano-technology, nuclear refinement, or -- more likely -- some unforeseen technology. At that point, all humanity will be subject to the Columbine/Virginia-Tech/September-11 crazies of the world. In short: don't buy any green bananas. --Sean 13:46, 9 September 2007 (UTC)
You sound like Debbie Downer. —Keenan Pepper 17:30, 9 September 2007 (UTC)
Based on recent mortality data from Canada shown here, out of every 100,000 babies born 99,268 survive to age 15 and 31 survive to age 108. So the probability that someone born in 1992 who has survived to age 15 in 2007 will survive a further 83 years to 2100 is 31/99,268, or about 0.03%. This assumes mortality rates remain unchanged for the next 80 years - in practice, they may well improve (leaving aside Sean's pessimistic scenario) so the probability may be higher (50 years ago the probability of a new born baby surviving to age 108 was only 0.003%). The actual probability for a specifc individual will be affected significantly by factors such a gender, life style, access to health care etc. Gandalf61 15:15, 9 September 2007 (UTC)

Thank you, that's the kind of answer I wanted. :) --124.254.77.148 07:46, 10 September 2007 (UTC)

The maximum age humans could possibly reach is sometimes said to be somewhere around 130 years. For the largest part, this has to do with dna strands getting shorter every time they are copied or something (don't know the details). At the moment, in western Europe, people grow to be around 80 on average. Over the next hundred years we're bound to get a fair bit closer to those 130 years. So if the average age has risen from 80 to 108 then that number would be 50%. Mind you, that is in the West, and assuming no catastrophies like war or drastic climate change. See also maximum life span. For a completely different option see the first item in this section on my user page. DirkvdM 18:44, 10 September 2007 (UTC)
You might also want to check back through our archives to several long and interesting threads about the highly controversial (but very entertaining) theory of quantum immortality which would suggest that everyone lives forever as far as they themselves are concerned. SteveBaker 19:18, 10 September 2007 (UTC)

[edit] wave ball

i was watching a re-run of nickelodeon's global guts and they had a wave ball in a pool that creates waves. could you please tell me how that ctually works? —Preceding unsigned comment added by 71.165.201.93 (talk) 08:48, 9 September 2007 (UTC)

Wave pool and [1]. They don't mention a wave 'balls' specifically but the basic concept is going to be the same. It might also help if you think of dropping a pebble in a body of water. You generate (small) waves. Basically the wave ball is doing the same thing but biger waves (think of dropping a rock) and at continually intervals. Nil Einne 09:30, 9 September 2007 (UTC)
Here are some specifications of "wave balls". As one might expect, the basic principle is a ball with a large amount of mass in it that is moved up and down to create waves. This particular company's product that I linked to seems to do some calculations as well to decide when the optimal time to move the weight up and down is, allowing it to multiply existing waves (and thus generating larger waves with less energy). --24.147.86.187 21:32, 9 September 2007 (UTC)
Yes using constructive interference makes a lot of sense. Somehow I never thought of that Nil Einne 20:39, 12 September 2007 (UTC)

[edit] Sensation of Vertigo

I used to think that the sensation one gets when looking over a cliff is that of "vertigo" but after reading the word's definition it doesn't seem to be the case. Is there a word for the sensation you get when looking over a precipous? Not a dizzying or moving sensation but rather, I am embarassed to say, something felt in the genitals. Again is there a name for this? 207.69.139.135 09:36, 9 September 2007 (UTC)

According to Acrophobia the sensation is best described as a spinning sensation. It doesn't mention any feeling in the genital region however Nil Einne 09:51, 9 September 2007 (UTC)
When faced with even the thought of a remarkably steep cliff or something involving heights and a falling hazard, I get a very tingly sensation under my feet. 81.93.102.185 10:53, 9 September 2007 (UTC)
When looking off a tall structure at a dizzying height, I usually have to fight the urge to jump. I'm not a suicidal person, but I've always had this compulsion. I think it has something to do with my mind trying to break the suspense. --Sean 13:28, 9 September 2007 (UTC)
Better read The Imp of the Perverse. —Steve Summit (talk) 14:35, 9 September 2007 (UTC)
Read it? I wrote it! --Sean 21:54, 9 September 2007 (UTC)
Did you! Well, then, my hat is off to you! —Steve Summit (talk) 22:51, 9 September 2007 (UTC)
There was a question about this jumping sensation on the desks a few months back, but i'm awful with searching archives. It was created by myself but I was probably acting under an IP at the time. Can any ultra-searchers find it? Capuchin 09:54, 10 September 2007 (UTC)
Wikipedia:Reference_desk/Archives/Language/2007_April_12#Desire_to_jump_from_a_height --Sean 13:24, 10 September 2007 (UTC)
Better not read just do it. I must admit I thought this feeling was vertigo. You don't say exactly what happens in the genital region, but could that just be scrotal piloerection?--Shantavira|feed me 17:55, 9 September 2007 (UTC)
I can concur with the unpleasant sensation when looking down from a great height, but never from an aircraft. I had always assumed this was vertigo. There is an unpleasant sort of "butterflies in the stomach" feeling but also a similar sort of sensation in the genitals, not piloeraction but a deeper uncomfortable sensation perhaps like the testicles being drawn up. I have never experienced giddiness - just the sure and certain feeling that this high vantage point is going to collapse. However the good news is that if you force your self to stay there the feeling will pass, maybe 5 minutes maybe 15 but it will go. It took at least 15 minutes at the top of the Space Needle! Richard Avery 07:47, 10 September 2007 (UTC)

[edit] "Natural genetic engineering"

Hello. I'm just a high school student. In searching around the internet I've run across a concept, "natural genetic engineering," which I can't quite grasp due to the high level it's discussed at. It's all related to a certain biologist named James A. Shapiro. Can someone explain to me, in layman's terms, what this is? In particular I'm interested to know if it means that the life forms undergoing "natural genetic engineering" somehow "know" how to adapt to a new environment. Here are some links:

http://shapiro.bsd.uchicago.edu/index3.html?content=genome.html shapiro.bsd.uchicago.edu/2007.Colchester.pdf http://members.aol.com/jorolat/nge.html http://www.springerlink.com/content/v655m288l6457115/

Any help appreciated. Thanks. 76.247.78.219 19:05, 9 September 2007 (UTC)

I might be too much of a fool to understand it, but it sounds like what he is calling "natural genetic engineering" is what the rest of the world calls "genetics." "Natural genetic engineering" is something of an oxymoronic term, if you ask me — genetic engineering implies human manipulation of what would otherwise be solely in the realm of nature; making it "natural" means removing the human component, yes? The work, from a brief skim, seems to be about the complicated ways in which genetic code can self-regulate and self-correct and that there is code which controls code and the like. All of which is true, but last I checked was subsumed by the definition "genetics" and, without human intervention, is not "genetic engineering" of any sort. The genetic code is quite complicated, and if he is just using the term to get outside of the simple "standard dogma" approach to genetics (which has been known to be misleadingly simple for a long time), I guess that is fine, but if you ask me the right way to do it—and the way most scientists seem to consider it—is to think of that complexity as being part of the definition of "genetics". Genetics has all sorts of regulatory functions built into the code itself—it is like a program that can reprogram itself, aside from doing all sorts of other things—and unless I've missed the mark, that's what he's chosen to label "natural genetic engineering." --24.147.86.187 21:27, 9 September 2007 (UTC)
I'm not an expert either, but it sounds like you got the basic idea right--the organism rearranges its genome in response to environmental changes. I've taken basic genetic sources but have not learned anything about that. What I've read about genetic adaptation are things concerning post transcriptional changes and feedback systems. An example of post transcriptional changes is when the transcribed DNA is spliced and rearranged. Feedback systems concern the regulation of protein production, where depending on the condition in the cell, the rate of a protein's synthesis is adjusted accordingly. The adaptation the guy talks about seems to infer changes in the genome itself. That is, sequences of DNA are rearranged to produce new programs (correct me if I'm wrong, anyone). The post transcriptional changes and feedback systems don't have anything to do with changing the genome. 128.163.224.222 21:44, 9 September 2007 (UTC)
For an opposing viewpoint: I was talking some time ago to a biologist I knew, and expressing dismay over some dangerous-sounding bit of "genetic engineering" that was then in the news, and he made the point that, in his view, he couldn't see any difference between that and regular old natural selection.
  • Natural selection: organisms are selected based on their "fitness for the environment", where this fitness is actually determined by how successfully they reach maturity and reproduce. Random mutations (induced by e.g. cosmic radiation) introduce variability which may produce superior environmental adaptations which will then be selected for. Also, viruses and other pathogens occasionally swap bits of genetic material between unrelated species; this can produce spectacular mutations (which, again, if beneficial will then be selected for).
  • Generic engineering: organisms are selected based on how successfully they reach maturity and reproduce, which is determined by whether some humans like the way they've come out, and let them reproduce. Random mutations (induced perhaps by deliberately-applied radiation) introduce variability which may produce desired adaptations which will then be selected for. Also, those humans may contrive to swap bits of genetic material between unrelated species; this can produce spectacular mutations (which, again, if beneficial will then be selected for).
The point is that, other than that there's an external agent attempting to direct the process towards a predetermined goal (which is, of course, most unlike natural evolution), there's really no difference in the underlying mechanisms or the potential outcomes of the "natural" versus "artificial" selection processes. —Steve Summit (talk) 01:59, 10 September 2007 (UTC)

[edit] Softwood shipping Grade Markings

Sorry to ask this question again, but I can't get the answer, please does anyone know where i can get the softwood shipping markings? I have them from 1976 but most have chaged as lots of new ones out now, The main places the wood markings are needed from is Sweden, Finland and Russia I hope someone can help this time, I have been searching for then for weeks thank you Jasimps —Preceding unsigned comment added by 86.130.174.194 (talk) 19:27, 9 September 2007 (UTC)

Can you ask a timberyard? I don't think there are many timberworkers online editing the science reference desk. Graeme Bartlett —Preceding unsigned comment added by Graeme Bartlett (talk • contribs) 06:52, 10 September 2007 (UTC)
Generally, if you get no responses after a couple of days it's because none of us know the answer. Continually re-asking the same question isn't going to get you anywhere. All reasonable questions are typically researched by at least a couple of people. For the record, I searched all over the place on the web and in paper encyclopedias in an attempt to answer your question the first time you asked it. I was able to find odd reports from conferences where shippers discussed timber markings - but I couldn't find any resource describing what they actually were. So sadly, I doubt anyone here will be able to help you. I like Graeme Bartlett's suggestion of asking someone who deals with timber shipments. But this service isn't magical - whilst we can usually come up with something, if the information just isn't out there, we can't find an answer for you no matter how many times you ask. Sorry. SteveBaker 12:40, 10 September 2007 (UTC)
True. But there's no need to scold the OP -- somewhere, in one of our RD instructions or guidelines, is or was the statement suggesting it's fine to re-ask a question after a week or so. —Steve Summit (talk) 12:53, 10 September 2007 (UTC)

Thank you all for trying anyway, I have been scolded and wont ask again! —Preceding unsigned comment added by 86.130.174.194 (talk) 13:21, 10 September 2007 (UTC)

Per the Ref Desk guidelines, it's perfectly OK to re-ask a question - and I'm certainly not scolding anyone for doing it. What the RD guidelines don't say (and they probably should) is that your odds of getting a decent answer fall to approximately zero if you didn't get anything useful the first time you asked the question. It's a sad fact of life that we can't answer everything - and if we can, we generally do so the first time around. SteveBaker 19:11, 10 September 2007 (UTC)

[edit] Creatine and Body Fat Percentage

I had my body fat percentage measured two weeks ago and it was 11.2%, but this week it was 13.5% using the same machine (its this thing that you put on your arm and I guess it sends a signal through you). I havnt gained any weight and my measurements havnt changed either. Is it because I started taking creatine? —Preceding unsigned comment added by 76.167.139.80 (talk) 20:34, 9 September 2007 (UTC)

It's probably just a reflection of statistical error in the technique used to measure body fat. Also, from your description, I'm guessing the apparatus you're using uses bioelectrical impedance analysis (BIA) for its measurement. I don't have any personal experience with the technique, but according to our article on BIA, it's apparently an inferior technique for measuring percent body fat. That in itself may account for the error.
Creatine by itself doesn't have an effect on muscle mass (and there aren't enough convincing data out there to reliably say creatine supplementation is at all worthwhile), but chances are that if you're taking creatine you're also weight training. In the long-term, weight training increases muscle mass and decreases body fat, although two weeks of it is unlikely to cause a dramatic change. --David Iberri (talk) 00:51, 10 September 2007 (UTC)

[edit] dietary supplement

what is and what is it used for .....Omega 3 Fish Oil?

angieb4756 —Preceding unsigned comment added by 12.207.120.234 (talk) 20:50, 9 September 2007 (UTC)

See Omega 3 fatty acid. Someguy1221 20:58, 9 September 2007 (UTC)