SkepticLance

buttacup Many other mammals have a better system. For example, cetaceans do not have our problem system. We have a perfectly useable set of nostrils, and a breathing passage that can lead directly from the nose to the lungs. It would require a widening of that passage, but that is simple engineering. The larynx and voice production would have to be within that passage, but again a mere detail. The point is that evolution, being an imperfect means of development can lead to a breathing/swallowing system that is frequently lethal. A good design by a good bio-engineer would avoid that.

An interesting item in the email version of New Scientist. http://www.newscientist.com/article/mg20126993.300-genes-control-quality-of-brain-connections.html?DCMP=NLC-nletter&nsref=mg20126993.300 I quote : "It is clear that intelligence is at least partly genetically determined. This was supported by the discovery in 2001 that the volume of the brain's grey matter, made up of "processor" cells, is heritable and correlates with certain elements of IQ (Nature Neuroscience, DOI: 10.1038/nn758). The amount of white matter, which provides the connections between these processors, has since been shown to be heritable too (Journal of Neuroscience, vol 26, p 10235)." And also "University of California, Los Angeles, scanned the brains of 23 sets of identical twins and the same number of fraternal twins, using a type of magnetic resonance imaging called HARDI. MRI scans typically show the volumes of different tissues in the brain by measuring the amount of water present. HARDI measures the amount of water that is diffusing through white matter, a measure of the integrity of myelin sheathing, and therefore the speed of nerve impulses. "It's like a picture of your mental speed," says Thompson. By comparing brain maps of identical twins, which share the same genes, with fraternal twins, which share about half their genes, the team calculate that myelin integrity is genetically determined in many brain areas important for intelligence. This includes the corpus callosum, which integrates signals from the left and right sides of the body, and the parietal lobes, responsible for visual and spatial reasoning and logic (see above). Myelin quality in these areas was also correlated with scores on tests of abstract reasoning and overall intelligence" With various indicators of intelligence being more closely correlated between identical twins than fraternal, it appears that intelligence is largely inherited, rather than being environmentally determined.

Stevie My congratulations on your advanced grasp of techno-babble. Suitable for a Star Trek script writer. Your device sounds good, but the possible technology behind it is more full of flaws than a sieve with holes. However, that is quite unimportant in scifi. You are fully entitled to do what scifi writers of the past have done, and just say that your protagonist built a time machine, and ignore how it might work. My earlier suggesiton of a rotating black hole came from a piece written by Stephen Hawking. Another possibility is a wormhole. However, that is pretty much impossible in reality. "Natural' wormholes are most likely too small to even permit a photon to pass through, even if they exist - thus conserving the speed of light barrier. There was a speculative article in Scientific American a few years back about possible wormholes (and other absurdities). Apparently, to make a wormhole big enough to permit a human to pass requires vast amounts of 'negative energy'. Since we do not know whether such a beast exists, or can exist, or any way to make it, even in small amounts, that seems a bit of unlikely. I suggest you do not worry too much about how the time machine works, and just rely on it as a plot device.

Any question relating to the imperfections of the 'creations' should be enough to embarass the creationists. For example : What idiotic creator would make humans with the opening to the gut (esophagus) and the opening to the lungs (trachea) side by side, with a lousy little piece of flesh to act as a valve between them? Every year, untold thousands of humans die of choking (like Mama Cass with her chicken sandwich) by inhaling as they swallow. What a horrible piece of design, if it was the result of creation.

The simple answer is that there is no simple answer. In other words, it all depends.... If a test is important enough, and if the experimenters do all they can to prevent unnecessary suffering, then the testing can be justified - at least to me. Sadly, there are still a lot of trivial and unnecessary tests carried out on animals, in which much suffering is inflicted. It is hard to justify those tests.

Stevie Going back to my earlier post = a rotating black hole might be a time machine, though we still not know for sure. The current 'super-cyclotron' is the large hadron collider, and some people believe it will destroy the Earth by making a mini black hole. I am suggesting a super-super-cyclotron in space, where a black hole will do no harm. The advanced science of the day makes a black hole, and sets it to spinning by throwing mass into it with a lot of velocity to make it spin. Once the spinning black hole is big enough, and spinning fast enough, to permit you to pass through the central hole, you have a possible time machine. http://answers.yahoo.com/question/index?qid=20090212102806AAun1md

Mokele Enzymes can indeed be very flexible. Hence my example of fish under ice. However, the most efficient enzyme systems will be close to 37 C. Increased temperature leads to faster metabolism (basic chemistry), but too hot means damage to enzymes. A temperature close to, or at 37 C seems to be pretty optimum.

Believe it or not, I have also read the bible cover to cover, but that was a long time ago, and I am now a total non believer, so I am unlikely to do it again. I have thought a lot about what makes a human, and the only thing that makes sense to me is the human brain. Any person who retains a fully functioning brain is human. We have cases where brain dead people have their life support systems switched off, or even are permitted to starve to death. I see no problem with that, though it might be emotionally distasteful to actually do it. Once the brain is gone, so is the humanity. Most abortions are carried out at a time when the foetus brain is no bigger than that of an earthworm. I regard that abortion as a crime about equivalent to the crime of stepping on an earthworm. I am aware of the argument that you are killing a potential human. However, if you take that argument to its logical extreme, you will force women to be perpetually pregnant from puberty to menopause, for otherwise they are denying life to potential humans. An obvious absurdity.

Paralith I could not agree more. I love it when women get involved in science, and the more women who do, the better. Why shoud 50% of our species avoid the most important field of study there is? However, my comment about using beautiful women as icons is still valid. It is mostly women who do it. Obviously not a perfect guide to gender, but it does seem to be the case more often than not.

As said, in Scifi you can discuss that which is not quite right. It is theoretically impossible to travel through space faster than light, but if that facts stopped scifi writers, it would wipe out most of the entire genre! One theoretical possibility for time travel is a spinning black hole. The event horizon then follows a toroid shape. In theory, if you dived through the centre of the torus - like going through the hole in a giant doughnut - you might end up in another time. More likely you would be torn apart - but this is scifi. Another possibility is that you would end in a different universe. Possible food for thought. Will your giant cyclotron permit a spinning black hole? Woe unto the Earth! Another possibility is to put your cyclotron in space - perhaps way out beyond Earth orbit. In vacuum and weightlessness, it would actually be easier to have such a giant device, and you could make it millions of kilometres long. A resulting black hole could then stay safely in solar orbit instead of destroying the Earth. Your protagonist would have to go through the torus in a space vessel - but why not?

The basic reason why evolution 'chooses' a specific temperature for warm blooded animals is to support enzyme action. Every enzyme has a specific temperature at which it works best. While evolution does result in certain creatures having enzymes that work at temperatures way off the optimum (eg fish that live under ice), the efficiency of those enzymes will never be as good as the efficiency of enzymes working at the optimum temperature. Since different enzymes will be a little different in that optimum, the actual temperature that an animal maintains will vary to a minor degree between species. However, it should always be close to the human 37 Celsius. At higher temperatures, enzymes lose efficacy, and can even be destroyed. It appears that bacteria, in general, have enzymes adapted to lower temperatures than human enzymes are. This means that humans can tolerate a slight increase in body temperature, which can kill many bacteria. Evolution has equipped us to go into fever when attacked by bacteria. This aids the recovery from illness.

Of course, you are asking for opinions in an area where everything is subjective and no scientific testing will provide answers - only opinion. I am not religious and religious dogma has no part in my opinions. My subjective and personal opinion is that the real question is : When does an embryo become human? This is based on the general observation that, in many circumstances, our culture considers it OK to kill animals, but not humans. Actually, in some circumstances our culture considers it OK to kill humans also - eg war - but I do not happily go along with that. So my answer is that it is OK to kill an embryo any time before it becomes human. So what is human? I believe it is based on the brain. Shape is nothing. A plastic doll has the shape. However, we can plot the development of the brain, and there is a time when the brain gets large enough to arouse the possibility that the embryo is now getting somewhat human. When that happens, we should call the killing of the embryo wrong. When is that? I do not want to give a definitive answer, since I am not an expert in the field. My guess is about half way through normal pregnancy, but others may dispute that, with more expertise than I have.

Paralith Even though I do not know you, I get the impression that you are a special kind of woman. I cannot comment on your looks, though I suspect that the need other women have to identify with a gorgeous woman as icon is probably more related to feeling deficient in that area. That is : a bit of wishful thinking. You, however, are a biologist, with a healthy self image bolstered by the knowledge that you are good in your field. Therefore, from that self image, you choose an icon more related to your academic interest than to wishful thinking. I respect that. Your comments about God, and the need for women to reproduce so painfully and dangerously are good. I agree. If we were created, then the creator did a ridiculously lousy job of designing the birth method. I add to that the incredibly poor design of the menstrual cycle, which causes enormous pain and discomfort to women, and the flow on impact of their male partners living through PMT. Why would a competent creator do such a lousy job of design?

Sayonara I am happy to accept your statement. However I am not happy to be called stupid, even by implication, by iNow. Thus I explained my reasoning, which in the absense of your personal knowledge, is valid. Nor did I say that YT was female. I just asked why several posts assumed maleness.

iNow I am well aware of the nature of the icon. Lieutenant Starbuck from Battlestar Galactica. I am also aware that the actress playing that role is quite beautiful, and that female psychology being what it is, lots of women take beautiful women as role models. I have noticed that female participants in this, and other forums frequently adopt beautiful women as icons. So that is not a stupid observation.

Why do you assume YT is male? The attached icon is female.

Sayonara There are lots of flavours of creationist. It is really the rabid fundamentalist type that I abhor - the ones that deny all the evidence of modern biology. My father was religious - traditional Christian - but always declared that the first books of the old testament were merely parables. He believed in 'creation' but only as carried out via evolution. Possibly a bit of a tricky set of beliefs to hold simultaneously, but not at all unusual. There is no problem with a Christian believing in some form of creation, but not blindly adhering to every part of the Old Testament.

My favourite is the vitamin C synthesis by the human body. We have the whole genetic complex that is used by other species to manufacture vitamin C, but in humans it is defective, with a single mutation stopping the process. Easy to explain in evolutionary terms (a mutation plus genetic drift at a time our ancestors were fruit eaters, and didn't really need the vitamin C manufacture.) But why would the creator have built into our bodies the entire gene complex and then deactivated it all with a mutation? Humans are now working on re-establishing the mechanism by means of gene therapy. http://www.lewrockwell.com/sardi/sardi91.html Why didn't God do that?

On the area of general science news, why pay anything? There are a number of ejournals that are free. I receive Science Daily, and New Scientist. The latter requires a financial subscription to see the full text of some articles, but many of the articles are free. Google for sciencedaily. It is an excellent source of general information, with numerous short articles covering a wide range of scientific topics. You receive an issue every day. In a similar way, Skeptic has an ejournal, which is free. Not as good as the written issue, but comes out much more frequently. I am often a bit disappointed with the paper journal, since it is often quite philosophical, rather than dealing with hard science. But don't restrict yourself to American sceptical publications. Skeptics groups exist all round the world, and most of them have excellent web sites. When you have time, visit the web sites. http://www.skeptics.com.au/ http://www.skeptics.org.nz/ http://www.indiansceptic.in/ http://skeptic.org.uk/ etc Some of these may lead you on to access to sceptical ejournals.

Charon is correct, though I would not have used the same argument. If a Ph.D. is simply a tool to make money, there are much better ways. However, there are many other reasons for getting a Ph.D. When I considered going back to university for a Ph.D. I realised that my motive would have been the increased status that comes with being called 'doctor'. That was enough for me to back away, since my motive was insufficient. However, others like the challenge. Some are into learning for its own sake. Some want the academic career in spite of it not being financially lucrative. Examine your motives. If they are good, then go ahead.

Psycho That distress is already there. Today, the genetic selection is purely by chance, depending on your parents' genes. In the future, it will not be the random nature of genetic parentage, but the deliberate choices made by parents. At the end of the day, in either situation, there are children who become "the beautiful people" who live full happy lives, and there are the unfortunates who live miserable lives, where they feel put down by those who were more fortunate. If anything, in the future with gene selection possible, the percentage of "beautiful people" will increase and the number of those who are made miserable by lousy genes will diminish. A net increase in happiness, and a net reduction in misery.

I am 60. 7 years ago, I did a university paper on microbiology. It was fun! I considered continuing to do a Ph.D. The main reason I didn't was financial. Go for it. Age matters not. We have seen people in their 70's getting Ph.D.s.

Society's attitudes change over time. It does not necessarily matter how much support it has now. More important is ten years, twenty, fifty from now, when the technology is much more accessible and much cheaper. I recall how artifical insemination of humans was treated in the 1960's when it was first mooted. My memory suggests massive disapproval. However, here it is. Common. And no-one gives a damn any more. And nor should they. The result is just a baby. If the baby is healthy, and loved, that is what matters. Personally I think it is fine to choose babies that are tall, or athletic, or beautiful, or intelligent. Surveys show that such people live better and happier lives that those who are short, physically incompetent, ugly or stupid. In my opinion, it is perfectly responsible - even wise - to give your child the best start in life if that option is available. My concern would run more to those who have bizarre tastes. For example ; in many animal experiments, a jellyfish gene has been inserted that makes the animal glow green. Imagine some nutter wanting that for their child! I would favour legislation that makes genetic insertion, or genetic selection restricted to those features that occur naturally in the human population, to avoid such bizarre choices, which would blight the life of the poor child bearing them.

Actually x was the weight of the whole ruler. Then 0.5x times 0.325 = 100 times 0.25 Or x = (100 times 0.25) divided by (0.5 times 0.325) Answer in grams.

The principle of moments say that, when a lever is balanced, the centre of mass on one side of the fulcrum multiplied by the distance from fulcrum equals the centre of mass on the other side multiplied by the distance from fulcrum on that side. In this case, I would hang the metre rule by a piece of string one quarter of the way from the end, and add known weights to the short end until it balanced horizontally. Since one quarter of the ruler to the left weighs the same as one quarter to the right, we can temporarily ignore those weights. This means that the weight of half the ruler, multiplied by the distance of its centre of mass (0.375 metres) equals the weights you have hung times the distance to the fulcrum (0.25 m). When you have this, just double the result to get the mass of the whole ruler. Suppose you got the ruler to balance with the fulcrum point at 0.25 metres, and 100 grams added at the short end. Call the weight of the ruler x. Then 0.5x times 0.375 = 100 times 0.25. Solve this equation for x. The result will be in grams. Simple.