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Lionel Mandrake

Profile Information

Gender: Male
Hometown: The Left Coast
Home country: USA
Current location: electrical wires
Member since: Sun Jul 1, 2007, 06:47 PM
Number of posts: 3,651

About Me

I study, play the piano, play chess and go, and enjoy the company of my wife, children, grandchildren, other relatives, and friends. I am a perennial student at a local university, where they let me take classes and use the library for free (because I'm old). My serious reading includes math, science, history, and biography. I enjoy science fiction and mysteries, which my wife and I refer to as "mind rot". And now on to politics. I hated Nixon and Reagan. I think W is a war criminal and was easily the worst president in US history. Thank Darwin he's gone. I will support any candidate who is a "dove". I support "plan B" without prescription for girls of all ages. I support free abortion on demand, without delay, and without the requirement to notify anyone, for all women and girls who want it. I think it's time to repeal the Bush tax cuts for corporations and the very rich. I think other damage done by conservative Supreme Court Justices rivals that done by the monster they put in the White House.

Journal Archives

Color vision and X-inactivation.

Normal color vision in humans is said to be trichromatic, since there are normally three types of cones in our retinas. The most common types of color deficiencies result from abnormal or missing genes on our X chromosomes. Most of the readers in the Science Group have probably heard that many men, but few women, are "red-green colorblind". This trait is said to be sex-linked and recessive, like baldness and many other abnormalities that affect more men than women.

Roughly speaking, if a man has such a trait and a woman is not a carrier for that trait, their children will not have the trait, but half of their daughters will be carriers. If a woman is a carrier and a man does not have the trait, half of their sons will have the trait, and half of their daughters will be carriers. If a woman is a carrier and a man has the trait, then half of their children of either sex will have the trait, and the daughters who don't have the trait will be carriers. These statements follow from the facts that every female cell has two X chromosomes and every male cell has only one X chromosome.

But the real situation is more complicated. In very precise color-matching experiments, women who are normally considered to be carriers have been shown to have a slight deficit compared to women who are not carriers. In other words, the genes for color deficiencies are not completely recessive. This has to do with the fact that one of the X chromosomes in each cell of a woman's body is inactivated, i.e., most of its genes are not expressed. The reason for X inactivation is to prevent a mismatch between males and females in the amounts of messenger RNA (and hence the amounts of protein) that are produced. In animals (but not plants) if the level of gene expression is off by a factor of two, the results are usually deleterious and often fatal. Even if the level is only off by 50%, as in trisomy 21 (Down Syndrome), there are serious consequences.

A female "carrier" of a sex-linked trait will have clumps of cells in which the X chromosome inherited from her father is inactivated, and other clumps in which the X chromosome inherited from her mother is inactivated. The patches of fur in a calico cat are similarly explained. The retina in each eye will have abnormal patches and normal patches. It's not surprising that such an eye does not perform quite as well as a completely normal eye.
Posted by Lionel Mandrake | Sat Jul 4, 2015, 06:38 PM (12 replies)

Oscar Peterson Trio plays "Down here on the ground"

Oscar Peterson - Piano
Sam Jones - Bass
Bobby Durham - Drums

Posted by Lionel Mandrake | Mon Jun 22, 2015, 05:10 PM (5 replies)

Our broken jury servitude system

Our jury servitude system provides an almost unlimited labor force which is forced to work for almost nothing. The court system wastes jurors' time in many ways: keeping jurors idle for hours in jury assembly rooms, sending hordes of them to courtrooms where they sit idly once again, waiting for the interminable voir dire process to exclude most of them, etc. The court system does all this because it has little incentive to use jurors' time efficiently.

An integral part of this economic distortion is excessive use of what are called peremptory challenges (defined below). We Americans pay little attention to how similar problems have been solved elsewhere in the world. Once when my time was being wasted in a jury assembly room and a judge came by to give the usual pep talk, I asked him what he thought about peremptory challenges. He said that of course he had his opinions but declined to say what they were. I mentioned that peremptory challenges had been abolished in England. The judge said that was interesting - he hadn't been aware of that. (!)

Today's LA Times has an editorial about peremptory challenges:

http://www.latimes.com/opinion/editorials/la-ed-peremptory-challenges-in-misdemeanor-trials-ab87-20150621-story.html
Posted by Lionel Mandrake | Sun Jun 21, 2015, 08:39 PM (38 replies)

Is there any limit to the greed of pharmaceutical companies?

The following story from the LA Times shows some consequences of our ridiculous drug prices. Only in America does the government encourage this abuse. For a private citizen, printing money is called counterfeiting and is prosecuted by the feds, but big pharma practically has a license to print money.

http://www.latimes.com/business/hiltzik/la-fi-hiltzik-20150621-column.html#page=1
Posted by Lionel Mandrake | Sun Jun 21, 2015, 08:29 PM (19 replies)

Happy solstice-eve everybody!

Tomorrow will be the longest day of the year (for those of us in temperate regions of the northern hemisphere), but today is almost as long. (By "day" I mean the interval from sunrise to sunset, not the 24-hour period which is also called a "day".) For those at mid-latitudes in the southern hemisphere, it's the shortest day. Our summer solstice is their winter solstice, and vice versa.

The sun will rise at 23.4 degrees north of east, and sunset will be at 23.4 degrees north of west. Hey, that's almost the title of a Hitchcock movie. (Actually sunset is roughly West by Northwest.)

For those at very high latitude there will be no sunrise or sunset today or tomorrow. But it will still be the "solstice" in the original sense of the word: that the sun is as far north in the sky as it will get this year. This can be observed by those above the arctic circle, but not by those who are wintering over in Antarctica (brr....).
Posted by Lionel Mandrake | Sat Jun 20, 2015, 02:48 PM (20 replies)

Why some saturated colors are darker than others.

Have you ever noticed that blue is darker than red, whereas red is darker than yellow? This gives blue ink the greatest contrast, and yellow the least contrast, against white paper. I've often wondered why this is, and I think I've figured it out.

Color vision involves cones (as opposed to rods). Humans with normal color vision have three types of cones in their eyes. I will refer to them as blue, green, and red cones, although the proper terms are short-wavelength (S), medium-wavelength (M) and long wavelength (L) cones. The following diagram shows the patterns of cones in the foveas of an eye with a normal retina (on the left) and one lacking red cones (on the right). The person with the latter eye suffers from a severe form of red-green colorblindness called protanopia.



The brightness of a color depends on the density of cones that are excited by light of that color. Red and green cones are dense in the normal fovea. Blue cones are very sparse and don't contribute much, if anything, to brightness. Blue light excites mainly the blue cones and has low brightness, i.e., it appears dark. Yellow light excites the red and green cones equally (or approximately so) and has high brightness, since it excites most of the cones. Red light excites mainly the red cones and is intermediate in brightness, since it excites only about half the cones.


Posted by Lionel Mandrake | Thu Jun 18, 2015, 11:59 PM (0 replies)

Shall we go to war over Transnistria?

This is very obscure, but bear with me. Transnistria is a landlocked part of Moldova bordering on Ukraine.



Why is this important? Because Russia has about 1000 soldiers there who need to be supplied with food, clothing, ammo, etc. and the only way to supply them is by crossing over Ukraine. President Poroshenko of Ukraine (whose shaky regime is backed by the US) has denied Russia permission to cross its territory. Putin is contemplating an airlift (like what we did in Berlin during the Cold War), but what happens if the Ukrainian air defense shoots down a Russian plane? The new cold war could suddenly heat up in a big way, and we would be involved.



This all relates to Kerry's recent visit to Sochi (the Black Sea resort where Putin has a dacha) and the Obama administration's subsequent attack on Kerry for not having rattled sabers menacingly enough during the four hours when he was talking with Putin. It seems that Kerry, who has seen war, is out of step with Obama, who has not.

For details, listen to
http://johnbatchelorshow.com/podcasts/tues-6915-hr-2-jbs-stephen-f-cohen-nyu-princeton-professor-emeritus-author-soviet-fates-and
Posted by Lionel Mandrake | Thu Jun 11, 2015, 04:53 PM (33 replies)

Today is the anniversary of when D Day was supposed to happen.

The invasion of Nazi-occupied France in 1944 was originally scheduled for June 5 but had to be postponed because of bad weather. The weather forecast for the following day was not quite as bad, so Ike decided that June 6 would be D Day.
Posted by Lionel Mandrake | Fri Jun 5, 2015, 02:49 PM (16 replies)

A tune to make you feel good

&spfreload=10
Posted by Lionel Mandrake | Fri May 29, 2015, 06:38 PM (1 replies)

Income Inequality

By now it's common knowledge that inequality in wealth and income has been increasing it the US over recent decades. While wealth inequality is hard to measure, income inequality is relatively easy to measure by such statistics as the percentage of income going to the top or bottom X percentage of households.

A problem with this sort of statistic is that X is arbitrary. We often hear about the bottom 10% and the top 1% or 0.1% or 0.01%, etc. No single value of X captures the whole economic picture.

There's a better way: the Gini index is familiar to people who study income inequality, but not to the general public. The Gini index is obscure because its definition is too mathematical for most people to understand. But for those who know a little calculus, it's simple and it's something well worth knowing about. If this is new to you, please take a look at

http://en.wikipedia.org/wiki/Gini_coefficient

While the Gini index is generally considered the best single measure of inequality, various refinements have been considered to describe other aspects of inequality. For example, here is an article about a way to define separate Gini indices for the poor and the rich:

http://www.maa.org/sites/default/files/pdf/upload_library/2/Jantzen-2013.pdf
Posted by Lionel Mandrake | Sat May 23, 2015, 08:51 PM (7 replies)
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