SMF

John. To support your notion that twin studies are poorly controlled you found a good twin study that supports my contention that this research is experimental and not just simple correlation, and now you are disparaging your find. I conclude that you don't understand the research. SM

Lemur. I think that some of the carbon composites used in recent aircraft construction (stealth military and the 777) could be used for cars. The question is whether this method is practical for construction and, especially, for structural repairs often required for cars. SM

Marat: Could you please document these three statements. I am not familiar with these concepts and would like to read up on the science. SM

John. You are agreeing with me on everything I have said but claiming I am wrong. The Schizophrenia opinion article you offered was about disease (infection of the mother during pregnancy) and the author admitted that it was only citing correlations, while the intelligence research article was a good twin study of the type that I have been saying is good science. Strange. You don't appear to understand what you are talking about, or how this type of science progresses, so further discussion is not worth pursuing. Perhaps someone else here can clarify for me how the Minnesota and Swedish twin projects are just producing correlational epidemiology, because I think this assertion is obviously incorrect. SM

OK John. The Schizophrenia article suggests that infection of the mother might be responsible for the disease. I asked you to provide evidence of phenotipic variability of normal traits, but you give me disease. In any case, because this article cautions against correlational studies regarding this relationship, saying- "Although epidemiological studies cannot establish causality," -it is basically an example, in your terms, of a bad example. I just love the the Jacobs et.al. (2001) piece because it is an excellent illustration of what I have been saying. Here is a twin study that is able to identify the contribution of the intrauterine environment component that affects intelligence, relative to the inherited and post uterine environmental component, that can be attributed to monochorionic versus dichorionic environments of monozygotic twins. But if I wished to play your game I could still ask about the effect of the competence of the delivery teams and the disposition of the family dog on the result. Instead, I think I will just accept this study as a good example of scientific investigation about which I have been talking. Just correlation eh, you make my point. SM

John, you are playing a distracting logical game. I don't believe that there are very many single studies, in any field, that by themselves don't have some uncertainty. This is why there is replication and extension of results by subsequent experimentation. Scientific certainty is never certain, it is always provisional and is accompanied with confidence limits. Further, like most research the twin studies are hypothesis driven and based on previous research. Your invoking of "just correlation" for this kind of research is inappropriate. Save it for the pop culture sassafras roots prevent cancer claims. If you wish to continue with this silliness, I challenge you to come up with a half dozen differences in normal individuals that can be attributed to normal variations of the placenta. Give me one example. Find me the study that shows the effects of normal placental variation and using your logic I could claim it is just correlation. How about the competence of the delivery teams? How about the disposition of the family dog? This is a game that real scientists do not play; instead criticisms are based on existing facts and contradictory evidence. What is yours for the twin studies? SM

I suggest that you study up on Robert Goddard's work. There are probably some pretty good sources and construction plans for his working rockets. Here is a decent Wikipedia article about him. SM http://en.wikipedia.org/wiki/Robert_H._Goddard#The_.27Goddard_rocket.27

In addition to what I and others have said above, I have a one word explanation based on the behavior of one of the members of my household just yesterday on the rug. Hairballs! Eat some grass and then yak it up. SM

Gnetic, could you please restate your question. I don't understand what you are asking well enough to comment. SM

So John, are you saying that in a large study which finds that if a trait is present that 100% of identical twins reared together, 100% of identical twins reared apart, 50% of nonidentical twins reared together or apart, but only 4% of adoptees reared together will share it, and 4% is the rate the trait is found in the general population as a whole, that the trait is not conclusively the result of genetic inheritance? This is an example of an extreme data set, but with large numbers of subjects the genetic component of many complex traits have been attributed, with high statistical significance, proportionally to inheritance or environment. This is what was contested in the discussion above. I don't think that anybody is claiming that simple demographic correlations with the frequency of some trait demonstrates causation. SM

Because with current technology there is absolutely no way to verify that dream content represents anything, assertions to the contrary are just unsupported opinion and speculation. SM

JohnG: You seem to be confusing simple correlation with the experimental evidence provided by genetic diversity. For some traits the genetic differences (lesions?) are there for scientific observation and the twin studies, for example, are much more than simple correlations. They are natural experiments. SM

DrRocket, Early percussion caps for black powder weapons was fulminate of mercury and was manufactured in the early 1800s. SM EDIT- a quick search finds http://www.powerlabs.org/chemlabs/fulminate.htm which shows how to make fulminate of mercury. I think that this may be illegal because it is a high explosive, but might be useful information for the OPs novel.

Eelpie. Cells, including neurons, recycle molecular components on some time scale. SM

Nathan. Note that 18th century would be mostly muzzle loading flint locks. Black powder made it through most of the 19th century and fowling was much less of a problem with black powder cartridges. It is even less when not using a revolver because the remaining solids don't coat the mechanism and are mostly swept from the barrel with each firing. For example, check out the Gatling gun. It could fire 150 to 200 rounds per minute (up to 600 in the 1864 model) for an hour. The extra barrels were to keep it cool. Black powder cartridges might be a better route for your novel because you don't have to make nitric and sulfuric acid and ether, and have to have oxygen free manufacturing to prevent ignition while washing out the acids (as per the String Junky link). I suggest you talk to some black powder enthusiasts about how to make or modify a modern semiautomatic weapon that could use black powder cartridges. SM