Radiohead - House of Cards

Cool video using lidar.

Unscientific

String theory gets pwned by xkcd:


Except for Bad Astronomy, it's not on any of the big physics blogs yet. CV, Asymptotia, Not Even Wrong.

Last night's lunar eclipse

Saturn at left, Regulus at top.


A widefield view during totality.

Periodic table as prints

Nature's The Great Beyond blog points out a periodic table made by print makers. A lot of them are cool, especially since it's hard to inspired by Praseodymium and Cesium (below).



Wired also had an article on alternative periodic tables two years ago.

Housewatch 4.10

It's been such a long time since a new episode of House, M.D., I almost forgot about my resolution to try and explain some of the science and medicine behind the show.

This week, the woman had breast cancer. But it wasn't in her breasts, it happened to be behind her knee. So how did it get there? It wasn't metastasis. Rather, it was a developmental abnormality that left her with some breast tissue that should have been resorbed before she was born.

So, we have to digress into embryology and teratology, which is embryology gone wrong. Many tissues are created, sorted out, grown, trimmed and pruned as an embryo becomes a fetus and then a baby. In the woman's case, a small patch of breast tissue wasn't properly disposed of during development, and it later became cancerous. 35 is young for breast cancer, but they did mention her mother died of it and that the patient had a prophylactic double mastectomy.

Was that really breast milk House extracted from the knee? Yes. Risperidone can stimulate breast tissue to produce milk.

So the women's treatment became a standard course of surgery and chemotherapy.

Finally, it's worth mentioning osteopetrosis (literally, bonestone). It's rare, basically the osteoclasts, which are supposed to clip and remodel bone, are defective. Or carbon anhydrase deficiency can lead to mildly acidic blood, which alters bone metabolism.

National Post doesn't understand evolution, either

The National Post, which is one of Canada's prime hotbeds of climate change denialism, has an editorial showing that they don't understand evolutionary genetics either.

Toni Vernelli, a dedicated British environmental crusader, may strike some as a deeply devoted champion of her cause. Frankly, she strikes us as more than a little off balance, perhaps even cultish. At 27 (Ms. Vernelli is now 35), she had herself sterilized in order to "protect the planet." Prior to that, she had an abortion rather than bring another consumer/ emitter into the world.

"Having children is selfish," she recently told London's Daily Mail newspaper. "It's all about maintaining your genetic line at the expense of the planet. Every person who is born uses more food, more water, more land, more fossil fuels, more trees and produces more rubbish, more pollution, more greenhouse gases and adds to the problem of over-population."

Toni Vernelli obviously gets the modern understanding of evolutionary genetics. Genes behave in ways that appear to us as selfish.

The National Post, obviously doesn't get it:

We like to think (as most people do) that giving another person life and agreeing to raise them through infancy, childhood and the teenage years into adulthood is the height of selflessness, not selfishness. How much easier to be able to come home from work when you want, not when a child needs picking up from school, or to go out when you want and not have to worry about being home in time to put children to bed and get the babysitter home. No pretending to enjoy animated television or movies. No sitting up nights nursing a scared and feverish little one. No 6:30 a.m. hockey practices. No fights with a ninth-grader over friends, clothes or hair. No worried late nights waiting for a high schooler to return with the car.

Yes, most people think having children is unselfish, because it "ruins" your previous life. Suddenly, you're a full-time child care worker. And having no children seems selfish, because you can do whatever you want, have more disposable income, and far fewer wrinkles than your child-rearing peers.

But from the gene's point of view, having children is exactly the most selfish thing that can possibly be done: pass on your genes to the next generation. That's point of kids. Keep the genes moving. From a gene's point of view, Vernelli is so unselfish her combination of genes are going to go extinct.

The National Post's stupidity continues, and I can't be bothered to pick it all apart. It winds up with:

Finally comes the most indelicate observation of all: If it is selfish of environmentalists to have children because of the damage those offspring would do, isn't it even more selfish for those environmentalists to stay alive themselves when they are consuming every bit as much water, land, fuel and timber, and producing just as much pollution and greenhouse gas? Why sacrifice the lives of their potential children before they have sacrificed their own? Mightn't suicide be the ultimate sacrifice an environmental extremist should make for his or her beloved planet?

Even suicide isn't a solution, nor the ultimate sacrifice for the environment. The bacteria, fungi, insects and worms that devour our bodies are all greenhouse gas emitters. So you can't win, even in premature death.

Comet 17P/Holmes

I observed Comet 17P/Holmes two nights ago, only visually. Compared to the previous night, I think it has brightened. On the 24th it was a little brighter than delta Per, which is magnitude 3.01. On the 25th it seemed brighter than gamma Per, which is magnitude 2.91, so I would say it is around 2.5-2.7.

It has a way to go before it can beat the brightest star in Perseus, Mirfak, at magnitude 1.79.

Comet 17P/Holmes

Comet 17P/Holmes has undergone a huge outburst, from magnitude 17 to 2.5, which means it's gone from being visible with only the largest telescopes to easy naked-eye visibility. I took this picture last night in my backyard.

More pictures and maps at www.spaceweather.com.

Housewatch, episode 4.1

I've decided to start explaining (or trying to) episodes of House, M.D. I like the show, medicine and Hugh Laurie.

Now, last night's episode was a case of mistaken identity. Not very medical.

Perhaps the most interesting medical hypothesis was crush syndrome, which I had never heard of. Basically, you get crushed by a building or other heavy object and unsurprisingly, it's not very good for you. It's common after earthquakes, but was first described during the Blitz, in London, (Bywaters EGL, Beall D. Crush injuries with impairment of renal function. BMJ 1941; 1: 427-32.) when buildings were falling left and right.

During crush syndrome, the large muscles of the body get compressed. Cutting off the blood supply causes cells to weaken, since they don't have the energy to maintain themselves, and they release potassium, phosphate, enzymes and the muscle protein myoglobin into the bloodstream. Ultimately, it's bad for the kidneys. But the brain and muscles can suffer too, often leading to amputation of a limb.

The patient also had acute respiratory distress syndrome. It's a little less interesting. When you have lots of other problems, it's not very surprising that the lungs get a little stressed and can fail when they fill with fluid.

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Now playing: Face (Extended Demo Edit) - G.R.R.L.
via FoxyTunes

Moon composite

A composite image of the moon. Two images stitched together. Taken with a Meade black and white DSI ccd camera, and my 85mm Stellarvue refractor.

M57

Took this photo the Ring Nebula, M57, Saturday night. Surprisingly good! Meade black & white DSI, and my 85mm Stellarvue refractor.

M13

I am surprised by how well this picture of globular cluster M13 turned out. Took it Saturday night, with a black and white Meade DSI and my 85mm Stellarvue.

Favourite science images

Following Carl Zimmer, who followed Larry Moran, I've picked my favourite scientific image from the Wellcome Trust's new Creative Commons-licensed image database. I wanted the spectrum of just the sun, but I guess I will have to accept some other stars too.

[Credit: Wellcome Institute, Creative Commons License.]

Recent solar activity

This is a picture I took of the sun yesterday. There are two large prominences, at 1 and 9 o'clock. On the disc there is one sunspot and some small filaments. No retouching to the picture.

Mapping the earliest quasars

This is my fifth post for the weeklong orgy of science blogging, Just Science. There hasn't been much astronomy, so here goes with a discovery from the early universe.

The Sloan Digital Sky Survey has been taking pictures of nearly the entire sky, mapping the universe bit by bit. the project is in its second phase.

Astronomers have been mining this for data. A group reports on new findings concerning the clustering of quasars in the universe's first billion years. Quasars are the superbright cores of active galaxies and are probably powered by black holes at the galaxy's nucleus. We only see them at far distances, which implies we are seeing them in their youth.

A map of 4000 quasars shows they are much more tightly clustered than expected. "Previous maps showed that more nearby quasars cluster like 'normal'galaxies," explained Princeton University graduate student Yue Shen, wholed the study. "But the clustering in our map is ten times stronger, the difference between a high contrast photograph and a washed out xerox."

Quasars and their galaxies cluster together, bringing together normal and dark matter. Dark matter is thought to far outweight the amount of normal matter in the universe. (See here for interesting simulations showing the distribution of the two types of matter.)

The strong clumping of the quasars suggests dark matter is also especially thick in these clumps. These kind of calculations help astronomers, astrophysicists and cosmologists figure out why our universe is the way it is now.

Rational, scientific assessments of drugs and narcotics

This chart above is the best thing I have seen in months. (I first saw it in mixmag.) It is from England's Science Select Committee, who were charged last year with finding out if England's policies on illegal drugs made any sense. The short is answer is no.

They reviewed the ABC classification scheme, A being worst, C being least worst, and found that the way the drugs had been ranked did not match scientific assessments on their effects and impacts on society and health.

So, they rearranged the impacts of drugs based on scientific assessments. The graph above, from this report, is what they ended up with. They left the old A, B, C labels on. It gives a good idea of how the political and societal judgments on drugs don't match the scientific assessment. For instance, alcohol and tobacco are both much higher than permitted by governments. Marijuana is much higher than its advocates like to admit, but lower than its detractor paint it. Ecstasy and LSD are much lower risks than any policy treats them.

Ponder the graph, for it is wonderful, and chock full of information.

When Inbreeding Isn't So Bad

My third Just Science post:

German researchers have found a fish that prefers to mate with its relatives, rather than strangers. The result, published in Current Biology, suggests inbreeding can be a good evolutionary strategy. Timo Thünken et al. studied African cichlids (Pelvicachromis taetiatus), a river fish. They found that the fish preferred to mate with unfamiliar close kin over unrelated kin. To put it in human terms, they'd rather mate with a distant cousin than a stranger.

Why would this be a good strategy? Well, your kin are more likely to help you than a complete stranger. In this species the male and female care for the young. They have to cooperate to care and feed their young broods, which requires time and energy. The researchers measured the degree of cooperation between related and unrelated parents, and found that related parents invested significantly more time in caring for the young. The desired result is to produce more, stronger offspring.

The scientists also found that there was no inbreeding depression, which is the fancy way of saying the children weren't talking one-eyed mutants with 18 flippers.

The scientists suggest there may be other instances of inbreeding waiting to be discovered.

To be crystal clear, this is not an endorsement of human inbreeding!


Thünken et al.: “Active Inbreeding in a Cichlid Fish and Its Adaptive Significance”. Publishing in Current Biology 17, 225–229, February 6, 2007 DOI 10.1016/j.cub.2006.11.053.

Erase and Rebuild to Program Stem Cells

My second Just Science post:

Biologists from Shanghai have discovered that cloned cells follow an "erase and rebuild" strategy to return to a state where they can begin dividing again. This isn't much of a surprise, since it's long been suspected that something like this happens. But it's nice to put a mechanism to things.
Huizhen Shang and colleagues report in a special stem cell issue of Cell Research that the developing (single) egg cells of mice erase many of the transcription factors and other modifications that control protein expression. The erasure strips away most of the programming done by the mouse's cells, leaving the cell in a "blank" state. (More technically, the chromatin, a mixture of DNA and proteins, factors are nearly all removed.) Then the egg cell gets rebuilt/reprogrammed after fertilization by sperm, and is ready to develop as a stem cell that forms a complete mouse.

In the early days of cloning (ten years ago), this reprogramming was done by electrocuting cells after a nucleus had been transferred into a denucleated oocyte. Nobody knew why this worked, but it did. With this new discovery, biologists can now determine how and what control factors are erased and reset.

Needless to say, but worth mentioning, is that this finding was not discovered in the U.S., due to the federal government's failure to support stem cell research.

Nitrogenase

Nitrogen is a fundamental element for life. There are no living organisms which do not depend on it, because it is found in DNA, RNA and protein. Therefore, obtaining it is absolutely essential.

The ultimate source of nitrogen is the atmosphere, which is 80% nitrogen gas, composed of two nitrogen atoms bound by three strong bonds. In this form, it is absolutely useless to life. It must be broken apart, and there are only a few ways of doing this. (Oxygen gas, which is composed of two oxygen atoms with two bonds, has been broken down every second of your life by enzymes.)

1. Lightning.
2. The Haber process.
3. Enzymes.

If we relied on lightning we'd be dead, since it doesn't produce enough freed nitrogen. The Haber process was only invented in the early 20th century, and is the source of fertilizer. That leaves enzymes, which are the source of nearly all the nitrogen in your body.

The enzyme that does this is nitrogenase. It is found in bacteria that live in the roots of plants. If you ever pull up a plant by its roots and find the roots covered in small nodules, those bumps are probably filled with nitrogen-fixing bacteria. There, they break atmospheric nitrogen and form ammonia and hydrogen gas.

N2 + 8e + 16MgATP + 8H+ = 2NH3 + H2 + 16MgADP + 16Pi.

This equation says take nitrogen gas, electricity, energy, protons, and convert them into ammonia, hydrogen gas, and spent fuel. Ammonia is easier to convert into nitrate, which is now biologically useful.

The enzyme is one of the most difficult ones to study. What happens "inside" it as it breaks nitrogen has been nearly impossible to observe by traditional methods, because the delivery of electrons can't be controlled. Biochemists know that the bonds are broken one at a time. A new paper by Dmitriy Lukoyanov et al. (subscription required) has unravelled much of the first part of the reaction. They find that no bonds are broken, and that nitrogenase accumulates four of the eight electrons before breaking a single bond. Their discovery finally links electronic states of the enzyme to hypothesized intermediates, and gives a better idea of the order of events performed by nitrogenase.

Just Science blogging week

I will be blogging this week for Just Science, where a bunch of science bloggers will be posting on science every day from February 5th to the 11th. Stay tuned. Should be a lot of great posts, maybe even some from me.

Stem cell debate

Bunk from beginning to end. Some day Levin and Kass and all the rest of the nuts will be gone from the President's Council on Bioethics. I hope it's soon.

Oekologie, first issue

Oekologie, a new blog carnival featuring writings on ecology and the environment, has posted its first issue.

Neil Tyson speaks the truth

Talking about the recent case of a teacher spouting religious anti-science nonsense in class, Neil de Grasse Tyson wrote in his letter to the New York Times:

To the Editor:

People cited violation of the First Amendment when a New Jersey schoolteacher asserted that evolution and the Big Bang are not scientific and that Noah’s ark carried dinosaurs.

This case is not about the need to separate church and state; it’s about the need to separate ignorant, scientifically illiterate people from the ranks of teachers.

Neil deGrasse Tyson

New York, Dec. 19, 2006

The writer, an astrophysicist, is director of the
Hayden Planetarium.

PS. 500th post!

The speed of links

Everybody else is doing it. Link to this! It's science!

Efston Science needs to learn some science

Efston Science, a large retailer of microscopes, telescopes, and other scientific gadgets in Toronto, had this ad attached in the latest issue of SkyNews which contains numerous errors.

The ad is for a device called a Radiometer. I've had one since I was a kid. It's pretty simple. Put it in sunlight and it spins. The glass case protects it from wind, and the sunlight shines on the vanes, powering it. The question is, how?




Efston's ad gets it wrong, two different ways. One, light is not made of atoms, it's made of photons. Two, light does not have a pressure that forces the vanes. (Sunlight (or any light) does have a pressure, but it is not strong enough to have any effect once it has passed through Earth's atmosphere.

So, how does it work? Wikipedia has a good explanation involving some of history's great physicists. Theory 2 is the one I've known since I was a kid. Sunlight strikes the sides of the vanes. The black side absorbs more heat than the white side, so it heats faster. Air currents flowing around the vane's edges push it along.

Ultimately, it comes down to two forces:

1. A partial explanation is that gas molecules hitting the warmer side of the vane will pick up some of the heat i.e. will bounce off the vane with increased speed. Giving the molecule this extra boost effectively means that a minute pressure is exerted on the vane. The imbalance of this effect between the warmer black side and the cooler silver side means the net pressure on the vane is equivalent to a push on the black side, and as a result the vanes spin round with the black side trailing. The problem with this idea is that the faster moving molecules produce more force, they also do a better job of stopping other molecules from reaching the vane, so the force on the vane should be exactly the same — the greater temperature causes a decrease in local density which results in the same force on both sides. Years after this explanation was dismissed, Albert Einstein showed that the two pressures do not cancel out exactly at the edges of the vanes because of the temperature difference there. The force predicted by Einstein would be enough to move the vanes, but not fast enough.

2. The final piece of the puzzle, thermal transpiration, was theorized by Osborne Reynolds, but first published by James Clerk Maxwell in the last paper before his death in 1879. Reynolds found that if a porous plate is kept hotter on one side than the other, the interactions between gas molecules and the plates are such that gas will flow through from the cooler to the hotter side. The vanes of a typical Crookes radiometer are not porous, but the space past their edges behave like the pores in Reynolds's plate. On average, the gas molecules move from the cold side toward the hot side whenever the pressure ratio is less than the square root of the (absolute) temperature ratio. The pressure difference causes the vane to move cold (white) side forward.

Strangely, scientists still aren't sure which is providing more force.