Saturday, November 29, 2008


Full Spectrum Daylight Light Bulbs

In the past couple of years "daylight" light bulbs have started to be generally sold. These are bulbs which have less yellow light and thus are closer to daylight. The Solux company website persuasively and toughly claims that its competitors all do a bad job of replicating sunlight, as the diagram here shows. If they are being truthful, their own $8 bulb is far better, though it needs a two-prong, non-standard fixture. I wonder whether any normal-fixture bulbs are better than the Reveal brand?

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Tuesday, November 11, 2008


When Does Human Life Begin?

A hard puzzle in abortion policy is when "human life begins". Is a one-celled embryo a human? Is an 8-month fetus a human? Is a 2-year-old a human?

How about if we approach the question from the other end. When does human life end? When is someone dead? It could be when his heart stops, but people do get revived often from that state and we don't call it resurrection. It could be when his brain activity stops, and I think that is the common criterion.

If the criterion for lack of life is lack of brain activity, then the one-celled embryo is not alive. Rather, we need to ask when a brain begins, and when it becomes active. A pro-abortion blog that discusses the brain criterion says that brain activity starts much later than the brain itself is formed, at 21 weeks, which is 5 months. The same blog says anti-abortion people claim the time is 10 weeks (which sounds more plausible to me, and even rather late).

November 18. Another approach would be to ask when an embryo has blood. Blood has special significance in the Bible. This webpage doesn't mention blood specifically, but it implies the embryo has blood somewhere in the 8 to 21 day range. There is a brain at 29-35 days, and brain waves at 40 days. In Arizona, at least, in 2007 of 10,486 abortions, 3,032 were at 6 weeks (42 days) or less. 102 were at 21 weeks or more.

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Saturday, October 25, 2008


Hydrogen Bonds

H. was asking me why ice floats in water-- that is, why solid water is lighter than liquid water. The answer has to do with hydrogen bonds. When hydrogen and oxygen form a molecule together, the hydrogen's lone electron is pulled toward the oxygen, so the other side of the hydrogen has a positive charge from its lone proton. This positive charge is attracted to the negative charge of another oxygen atom's electrons, forming a hydrogen bond. Well, that's my simple story.

The Edinformatics article on ice is good. It has pictures too. It explains that in ice, the hydrogen bonds hold the water molecules apart in a lattice with lots of space, but in water, the molecules do not have such orderly hydrogen bonds.

Here's what Edinformatics's article on hydrogen bonds says:

As the name "hydrogen bond" implies, one part of the bond involves a hydrogen atom. The hydrogen must be attached to a strongly electronegative heteroatom, such as oxygen, nitrogen or fluorine, which is called the hydrogen-bond donor. This electronegative element attracts the electron cloud from around the hydrogen nucleus and, by decentralizing the cloud, leaves the atom with a positive partial charge. Because of the small size of hydrogen relative to other atoms and molecules, the resulting charge, though only partial, nevertheless represents a large charge density. A hydrogen bond results when this strong positive charge density attracts a lone pair of electrons on another heteroatom, which becomes the hydrogen-bond acceptor.
In ice, the crystalline lattice is dominated by a regular array of hydrogen bonds which space the water molecules farther apart than they are in liquid water. This accounts for water's decrease in density upon freezing. In other words, the presence of hydrogen bonds enables ice to float, because this spacing causes ice to be less dense than liquid water.
Someone else says:
The hydrogen bonds that form between water molecules account for some of the essential — and unique — properties of water.

* The attraction created by hydrogen bonds keeps water liquid over a wider range of temperature than is found for any other molecule its size.
* The energy required to break multiple hydrogen bonds causes water to have a high heat of vaporization; that is, a large amount of energy is needed to convert liquid water, where the molecules are attracted through their hydrogen bonds, to water vapor, where they are not.

Two outcomes of this:

* The evaporation of sweat, used by many mammals to cool themselves, achieves this by the large amount of heat needed to break the hydrogen bonds between water molecules.
* Moderating temperature shifts in the ecosystem (which is why the climate is more moderate near large bodies of water like the ocean)



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Tuesday, October 21, 2008


Significant Figures

I haven't used this idea since high school, really, but it comes up now and then, so I looked it up in Wikipedia. 100 has one significant figure, as do 20 and 23 and .0001, the article says. The number .00200, however, has three significant figures. The number 1.234 has 4 significant figures. Digits beyond accurate measurement don't count as significant. There is ambiguity, however, in whether 100 feet really has just one significant figure. It may be that you have measured it to the nearest foot, in which case it really has three significant figures.

The real importance of significant figures comes in doing arithmetic. If you run 100 yards in 11.71 seconds, and the 100 has three significant figures, then the speed should be written with three significant figures as 8.54 yards per second, not as 8.53970965 yards per second.

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Monday, October 20, 2008


Optical Illusions

U. of Washington has a good optical illusion-experiment site. It has the Muller-Lyon illusion below and lots more that['s harder to post in this blog.

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Saturday, October 18, 2008



From the Wikipedia entry on the constellation Cygnus, the Northern Cross, one of the easiest to find this time of year:

The constellation also contains the X-ray source Cygnus X-1, which is now known to be caused by a black hole accreting matter in a binary star system. The system is located close to the star Eta Cygni on star charts.

Eta Cygni is in the long part of the neck of Cygnus, about halfway from the wings to the head. Cygnus X1 isn't visible to the naked eye, though, and Eta Cygni is very faint.

Beta Cygni is Albireo, a double star, at the swan's head. Alpha Cygni, the tail, is the brightest star, named Deneb.

Cygnus contains several variable stars too, as this website describes.



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Thursday, July 24, 2008


Environmental AIDS Transmission

I wonder what the truth is about the danger of getting AIDS from such things as sneezes or toilet seats. The danger can't be too great, or we would come across numerous cases where that method of transmission could be proved. On the other hand, I am skeptical of the claims that no such cases occur. Would someone making that claim really be willing to share a handkerchief with someone in the last stages of AIDS? In the scientific literature, look carefully for language such as "No cases have been found..." or "No cases have been proved...", as opposed to "It is impossible to have transmission by ...". I haven't heard of any experiments on the subject. What would be useful would be to see if an animal can be infected without direct contact with an infected animal. Animals cannot be infected with the same HIV virus as humans, but even moderate similarity in the viruses would tell us something.

It isn't widely known that the HIV virus has a remarkable ability to survive outside of a human body. It can even survive drying! This implies, doesn't it, that it must be common for measurable amounts of HIV virus to be transmitted enviromentally. Since we don't see cases of that, it must be that the virus can't get where it needs to go in the body (e.g., maybe it can't get through the nasal membrane) or those amounts are not big enough to survive initial attack by the immune system, or even to stimulate measurable immune reactions.

Here are some notes from a couple of articles.

"Cell-free and cell-associated human immunodeficiency virus cultures suspended in 10% serum remained infectious for several weeks at room temperature. The stability was further increased when cell-associated virus was suspended in neat serum. When dried onto a glass coverslip, virus remained infectious for several days, although cell-associated virus lost infectivity more rapidly than cell-free virus."

The article says this ability to survive is similar to that of other viruses that have lipid envelopes around them.

JOURNAL OF CLINICAL MICROBIOLOGY, Feb. 1994, P. 571-574, Survival of Human Immunodeficiency Virus in Suspension and Dried onto Surfaces J. vAN BUEREN,* R. A. SIMPSON,t P. JACOBS, AND B. D. COOKSON Vol. 32, No. 2.

I found a good comparison of different germs' survival times. The article itself is about accidental jabs from needles.

30-50% of Australian drug users have been exposed to hepatitis B (as shown by having antibodies against it), but only 1-2% are infected. The hepatitis B virus can survive for a week if dried. It can be frozen and thawed 8 times and the DNA is still intact. Even a minute amount of infected blood can transmit the disease, since it has high concentrations and is virulent. It is often transmistted "environmentally"-- that is, from surfaces contaminated by body fluids or through the air.

50-60% of Australian drug users are infected with Hepatitis C. It survives for 2 days dried.

1% of Australian drug users are infected with HIV. THat is remarkably low-- aren't rates for American homosexuals who frequent homosexual venues more like 20%?

Blood-borne viruses and their survival in the environment: is public concern about community needlestick exposures justified? Thompson, Boughton and Dore. 2003 VOL . 27 NO. 6 AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH.

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Tuesday, June 10, 2008


Nicotine Prevents Senility?

From Wikipedia:
With regard to neurological diseases, a large body of evidence suggests that the risks of Parkinson's disease or Alzheimer's disease might be twice as high for non-smokers than for smokers.[26] Many such papers regarding Alzheimer's disease[27] and Parkinson's Disease[28] have been published.

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Thursday, February 14, 2008


The Danger of Smoking. It's hard to find good information on how much smoking increases a person's risk of death. Actuarial tables, it seems, say that male smokers die about 7 years before non-smokers, and I think that controlled for weight, but it didn't control for most of the reasons people who choose to smoke die earlier than people who do not. An hour's Web search leaves me highly dissatisfied with the research done. I don't think medical researchers think of controlling for ethnicity, education, and income, for example. It would also be a good idea to take any study and see if its methodology would also predict, for example, that smoking causes an increase in car accidents or in criminality. I bet all methodologies would, and the only question is the extent of it.



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Monday, February 4, 2008


Liberals and the Evolution of Man. Steve Sailer notes a contradiction in the liberal view of Man: it vociferously supports evolution of mankind, but vociferously opposes the implication that genetic differences evolve. Sailer uses Race as the undesired implication, but the inheritance of intelligence and behavior is an equally good example.
Perhaps the two doctrines currently most de rigueur for entry into intellectual polite society:

1. That humanity evolved from lower animals according to the process of natural selection outlined by Charles Darwin.

2. That humanity has not evolved any patterns of genetic variation corresponding to geographic ancestry … well, none other than the obvious ones that we can all see.

These two concepts are directly contradictory, as former UCLA professor of science education Cornelius J. Troost points out in his new book Apes or Angels? Darwin, Dover, Human Nature, and Race....

As Troost notes, the second of these two status shibboleths asserts that Darwinian evolution suddenly—magically!—stopped at the exact the moment when Darwinian logic says it should have sped up: when the ancestors of modern humans first left Africa for new climates.

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Tuesday, December 11, 2007


Meteors. My brother recommended to me the powerpoint file, "Lincoln Science Club Asteroid Night Dr. Steve Ostro, JPL Nov. 29, 2007". It has lots of good graphics and, especially, info on sizes of possible crashes between the earth and meteors.



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Tuesday, December 4, 2007


Evolution. "Microevolution looks at adaptations that concern only the survival of the fittest, not the arrival of the fittest" (Gilbert, et. al. 1996, p. 361). The anti-ID site Panda's Thumb gives the abstract for the Gilbert paper, which it seems gives an alternative to ID for the puzzle of macroevolution:
“A new and more robust evolutionary synthesis is emerging that attempts to explain macroevolution as well as microevolutionary events. This new synthesis emphasizes three morphological areas of biology that had been marginalized by the Modern Synthesis of genetics and evolution: embryology, macroevolution, and homology. The foundations for this new synthesis have been provide by new findings from developmental genetics and from the reinterpretation of the fossil record. In this nascent synthesis, macroevolutionary questions are not seen as being soluble by population genetics, and the developmental actions of genes involved with growth and cell specification are seen as being critical for the formation of higher taxa. In addition to discovering the remarkable homologies of homeobox genes and their domains of expression, developmental genetics has recently proposed homologies of process that supplement the older homologies of structure. Homologous developmental pathways, such as those involving the wnt genes, are seen in numberous embryonic processes, and they are seen occurring in discrete regions, the morphogenetic fields. These fields (which exemplify the modular nature of developing embryos) are proposed to mediate between genotype and phenotype. Just as the cell (and not its genome) functions as the unit of organic structure and function, so the the morphogenetic field (and not the genes or the cells) is seen as a major unit of ontogeny whose changes bring about changes in evolution.”

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