Ancora Imparo

30 November 2006

Science News Update (30 Nov 2006)

Filed under: humor,science — Darmok @ 09:57 UTC

I thought I’d share some interesting developments in the world of science.

More on polonium

CNN reports that twenty-one people have now been referred to a specialty clinic for further testing. In addition, radiation has been found on two British Airways airplanes that either Mr. Litvinenko or his contacts travelled on. The 33,000 passengers who have flown on those planes are being contacted for screening. In a column on Nature’s web site, Nicola Jones discusses the difficulty in determining the identity of a poison and why it took so long to recognize the polonium-210. (See my two previous posts on this.)

Cutting back carbon dioxide emissions

As Catherine Brahic of New Scientist reports, Europe has begun setting stricter caps for carbon dioxide emissions. This will help bring them in line with the Kyoto Protocol, an international treaty intended to reduce greenhouse gases. The European Union, Russia, India, and Canada have ratified the treaty; Australia, the United States, and China have not (there are many other nations involved as well).

(more…)

Video Games as an Anti-Obesity Tool?

Filed under: biology,medicine,public health,science,technology — Darmok @ 05:34 UTC

The prevalence of obesity has been increasing at a tremendous rate in industrialized countries. In the United States, where the problem is most pronounced, three-fifths of adults are overweight, and almost a quarter are obese (source, CDC):

In 2005, among the total U.S. adult population surveyed, 60.5% were overweight, 23.9% were obese, and 3.0% were extremely obese. Obesity prevalence was 24.2% among men and 23.5% among women and ranged from 17.7% among adults aged 18–29 years to 29.5% among adults aged 50–59 years…. Among racial/ethnic populations, the greatest obesity prevalence was 33.9% for non-Hispanic blacks. Overall, age-adjusted obesity rates were 15.6%, 19.8%, and 23.7% for the 1995, 2000, and 2005 surveys, respectively.

Children are affected as well. Also according to the CDC,

The most recent data indicate that in the United States about 16% of children ages 6–19 years are overweight. Since the 1970s, overweight has doubled among young children aged 2–5 years and tripled among school-aged children aged 6–19 years.

(more…)

29 November 2006

New Horizons Sights Pluto

Filed under: astronomy,science,technology — Darmok @ 12:05 UTC

Probe spots the dwarf planet for the first time


False-color images from New Horizons, animated to show Pluto’s movement. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

New Horizons, NASA’s Pluto-bound craft, just passed an important milestone (kilometerstone?). As reported by NASA,

The New Horizons team got a faint glimpse of the mission’s distant, main target when one of the spacecraft’s telescopic cameras spotted Pluto for the first time.

The Long Range Reconnaissance Imager (LORRI) took the pictures during an optical navigation test on Sept. 21–24, and stored them on the spacecraft’s data recorder until their recent transmission back to Earth. Seen at a distance of about 4.2 billion kilometers (2.6 billion miles) from the spacecraft, Pluto is little more than a faint point of light among a dense field of stars. But the images prove that the spacecraft can find and track long-range targets, a critical capability the team will use to navigate New Horizons toward 2,500-kilometer wide Pluto and, later, one or more 50-kilometer sized Kuiper Belt objects.

(continue reading at NASA’s web site) (more…)

Further Developments in Litvinenko’s Polonium-210 Poisoning

Filed under: chemistry,medicine,science — Darmok @ 02:35 UTC

In an extensive follow-up article, the BBC discusses some of the developments that have taken place since I last discussed the apparent poisoning of Alexander Litvinenko. The offices of a security and risk management company that Mr. Litvinenko had visited has traces of radiation; also, radiation has been found in the offices of Boris Berezovsky, a friend that Mr. Litvinenko had visited that day.

In addition, 1,121 people have called a helpline arranged by the health service; 68 cases were followed up and eight people have been referred for specialty testing, according to the BBC. Test results should be available in the next few days, New Scientist reports.

In a separate article, Rob Edwards of New Scientist discusses the difficulties and peculiarities of polonium-210 poisoning:

Nick Priest, an expert on polonium-210 who used to work with the UK Atomic Energy Authority, argues that it would be no easy matter to obtain enough to kill someone. “I find it difficult to believe that it was sourced in the UK or the European Union,” he said.

“All the signs point to it being a sophisticated operation,” he told New Scientist. “You would need a reactor capable of producing and irradiating materials and a radiochemical laboratory.”

However, once obtained, it appears it would be a simpler matter to actually administer the poison.

In solution as a citrate, nitrate or other salt, it could be rendered tasteless and easy to slip into a drink, [Mr. Priest] says. Up to 50% would be taken up by blood and tissue fluid, delivering serious radiation doses to different parts of the body.

Further reading

Related posts

28 November 2006

Learning to Walk

Filed under: computers,engineering,research,science,technology — Darmok @ 03:25 UTC

Scientists watch the robot attempt to walk
Credit: Lindsay France/Cornell University. Source: PhysOrg.com.

Josh Bongard and his colleagues at Cornell write in the November 17, 2006, edition of Science (see abstract) about a new robot they have built. As reported on PhysOrg.com (thanks to Food not Bourgeoisie for spotting this), the robot develops a model of self to learn how to move, perhaps somewhat similar to the way human babies learn:

Nothing can possibly go wrong … go wrong … go wrong … The truth behind the old joke is that most robots are programmed with a fairly rigid “model” of what they and the world around them are like. If a robot is damaged or its environment changes unexpectedly, it can’t adapt.

So Cornell researchers have built a robot that works out its own model of itself and can revise the model to adapt to injury. First, it teaches itself to walk. Then, when damaged, it teaches itself to limp.

(continue reading at PhysOrg.com)

The robot is programmed with a list of its parts, but not how they are connected or used. Instead, it uses a process that is a mixture of scientific method and evolution to learn how to move. It activates a single random motor, then, based on the results, it constructs fifteen varying internal models of how it might be put together. Next, it decides on commands to send to its motors, selecting commands that will produce the largest variation between models. It activates its motors and based on the results, the most likely model is selected. Variations on this model are constructed, and the robot again determines which test movement will produce the largest difference in movement between models. (This sort of repeated variation and selection is sometimes called evolutionary computation.) After sixteen cycles, the robot uses its best model of self to determine how to move its motors to move the farthest. It then attempts to move (usually awkwardly, but functional).

In a second part of the experiment, the researchers simulated injury by removing part of a leg. When the robot detects a large discrepancy between its predicted movement and its actual movement, it repeats the sixteen-cycle process, generating a new model of self and new way to walk.

(more…)

27 November 2006

Artificial Sun

Filed under: physics,research,science — Darmok @ 10:34 UTC

Cutaway of ITER
Cutaway schematic of ITER. Note the size of the human for scale. Published with permission of ITER.

I strongly support international collaboration, so I was excited to read on Bainite’s blog that ITER has been formally announced. ITER is a project to demonstrate the feasibility of fusion power on a large scale; it is a joint project between the European Union, Japan, the People’s Republic of China, India, the Republic of Korea, the Russian Federation, and the United States.  The planned location is in Cadarache in southern France (approximate location 43°41’55.65″N 5°44’30.61″E). ITER will fuse deuterium and tritium, contained by magnetic fields. The resultant high-energy neutrons will produce heat. In a fusion power plant, this heat would then be used to produce electricity; however, as ITER intended for research and demonstration, the heat will be allowed to escape.

Fusion is a form of nuclear energy. In fact, it’s the way our sun and all the stars produce energy, which means that ultimately, it’s the source for almost all energy on Earth. The energy from the sun powers solar panels, heats air to produce wind currents, and evaporates water which flows back down to produce hydroelectric power. Plants capture sunlight to make their food in a process called photosynthesis; animals (including humans) eat those plants or eat animals who ate those plants to obtain food. Similarly, our fossil fuels—such as coal, oil, and natural gas—are formed from the remains of plants and animals that died millions of years ago.

The form of nuclear energy used in today’s power plants is fission, in which a large atomic nucleus is split into smaller pieces, releasing energy. While this results in millions of times at much energy as conventional chemical methods like burning coal and avoids producing greenhouse gases, it still produces radioactive waste products. On the other hand, fusion combines two small atomic nuclei: this releases even more energy than fission, and does not produce any toxic waste products. However, the trick is that it is technically much more difficult to control and harness the energy. Of course, we already possess the ability for uncontrolled fusion—the hydrogen bomb—which releases its energy all at once.

(more…)

Family Circle

Filed under: art,biology,evolution,science,visualization — Darmok @ 06:30 UTC

Tree of Life
Source: David M. Hillis, Derrick Zwickl, and Robin Gutell, University of Texas

In my previous post I mentioned “Pale Blue Dot,” a photograph taken by Voyager 1 from the outer reaches of the solar system showing Earth as a barely visible dot of light. But even on Earth, we humans are just one in a family of millions.

Brett Keller discusses in his blog Brett Keller & the World a remarkable “tree of life” published a few years ago in the prestigious journal Science. This “tree,” arranged in a circular format, was developed by David Hillis and colleagues at the University of Texas. They selected around three thousand species, trying to include representatives from all major groups. You may read more about it and see where our species, Homo sapiens, fits in at Mr. Keller’s blog.

Phylogenetic tree
Possible phylogenetic tree

These representations, more formally called phylogenetic trees, are intended to illustrate the evolutionary relationships between species. Lines are drawn from two species (call them A and B) that are closely related, meeting at a vertex called a “node” representing the most recent species that is ancestral to the both of them. Another node may occur further up, representing the most recent common ancestor of the A-B ancestor and species C, and lines will be drawn to both of those. And perhaps even further up is the ancestor to species A, B, C, and D, with one line going to the A-B-C ancestor and one going to species D.

(more…)

26 November 2006

Night on Saturn

Filed under: art,astronomy,science — Darmok @ 11:06 UTC

About a month and a half ago (11 Oct 2006), NASA released this absolutely stunning image of the night side of Saturn, taken from a composite of 165 Cassini photographs:

Night on Saturn
Source: NASA

NASA explains how the image was obtained:

With giant Saturn hanging in the blackness and sheltering Cassini from the sun’s blinding glare, the spacecraft viewed the rings as never before, revealing previously unknown faint rings and even glimpsing its home world.

This marvelous panoramic view was created by combining a total of 165 images taken by the Cassini wide-angle camera over nearly three hours on Sept. 15, 2006. The full mosaic consists of three rows of nine wide-angle camera footprints; only a portion of the full mosaic is shown here. Color in the view was created by digitally compositing ultraviolet, infrared and clear filter images and was then adjusted to resemble natural color.

(continue reading at NASA’s web site)

(more…)

25 November 2006

Litvinenko Apparently Poisoned with Polonium-210

Filed under: chemistry,physics,science — Darmok @ 11:26 UTC

Former Russian spy Alexander Litvinenko has been in the international news after suddenly falling ill earlier this month, then dying on 23 November. The cause of his illness confounded his physicians, who initially postulated that might have been poisoned with thallium. However, in a surprising twist, the cause of death now appears to be poisoning with radioactive polonium-210 (210Po). That is, the poison did not work by the usual chemical means, but instead released radiation as it decayed inside his body. Given this unusual method of toxicity, officials in the United Kingdom are now trying to determine how next to proceed. Debora MacKenzie writes in the New Scientist

“This is an unprecedented event in the UK,” said HPA [Health Protection Agency] chief executive Pat Troop. “It is the first time someone in the UK has apparently been deliberately poisoned with a radioactive agent.”

The agency is now assessing the health risks posed to members of the public who may have come into contact with Litvinenko, including family members and hospital staff who cared for him during the weeks he spent in hospital. They are also trying to decide the safest way for pathologists to conduct an autopsy of his body, and indeed whether such a procedure is safe enough to be performed at all.

Polonium on periodic table, from Wikipedia
Source: Wikipedia

Polonium is an extremely rare element. It has an atomic number of 84, meaning that it has 84 protons (and therefore, 84 electrons); its position in the periodic table is shown here courtesy of Wikipedia. There are 25 known isotopes of polonium; polonium-210 (with 126 neutrons) is the most common. Polonium and every element with a higher atomic number (that is, 84 and up) are radioactive; that is, they are unstable, and spontaneously decay into other elements. Ms. MacKenzie goes on to write

Polonium is a radioactive element that is used industrially as an anti-static material. It is difficult to get hold of and not used regularly by research scientists, but very small traces of it occur naturally. The metal is usually made by bombarding the element bismuth with neutrons.

“To poison someone, large amounts of polonium-210 are required and this would have to be manmade, perhaps from a particle accelerator or a nuclear reactor,” said Dudley Goodhead at the UK’s MRC Radiation and Genome Stability Unit. “Polonium has a half-life of 138 days. This means that if that was the poison it will still be in the body and in the area – which makes it relatively easy to identify.”

There are several ways for radioactive decay to occur. Polonium-210 undergoes alpha decay, emitting an alpha particle (two protons and two neutrons, essentially a helium-4 nucleus). As a result, 82 protons (and 124 neutrons) are left. This is lead-206, which is stable. Alpha particles are quite massive, so they cannot penetrate solid matter very well. Therefore, polonium-210 must be inside someone’s body to inflict much damage—so it must be ingested, inhaled, or administered through a wound, according to Roger Cox, director of the UK’s Centre for Radiation, Chemical and Environmental Hazards. Mr. Cox believes that Mr. Litvinenko would have to ingest the polonium to account for the large amount found.

According to Scotland Yard, “Traces of polonium-210 were found at the Itsu sushi restaurant in Piccadilly, the Millennium Hotel, Grosvenor Square, and at Mr. Litvinenko’s home in Muswell Hill, London.” The investigation will continue—Britain’s top-level Cabinet team has met, and the country has asked Russia to assist with the inquiry, according to CNN.

Related posts

Is It Getting Hot in Here?

Filed under: environment,global warming,science — Darmok @ 07:22 UTC

The current issue of Scientific American features its yearly SA 50 Awards. It awarded Policy Leader of the Year to former U.S. Vice President Al Gore for his work in helping to educate the public about the danger of climate change, focusing on global warming. His efforts have culminated in An Inconvenient Truth, a documentary film (and also a book) that has been praised by both scientists and movie critics. J.R. Minkel and Gary Stix write

It sounds improbable: a documentary film about global warming, starring Vice President Al Gore, has become the third-highest-grossing documentary of all time. After his loss in the 2000 presidential election, Gore began giving a talk on global warming to audiences around the world. An Inconvenient Truth is the film version (also appearing in book form) of his multimedia presentation. Remarkably, its heavy use of PowerPoint slides actually adds to the narrative, which interweaves explanations of climate science with defining episodes from Gore’s life to convey a mix of alarm and hope.

The film is a paragon of clear science communication. It explains the workings of complex physical phenomena, such as the jet stream, while chronicling the reality of glaciers receding and the increase in carbon dioxide emissions and global temperatures. Gore, meanwhile, succeeds in bringing the “moral imperative” of reducing greenhouse gases to a personal level, attempting to convince viewers that their own actions can make a difference.

(continue reading at Scientific American)

Temperature record for the past 150 ears
Source: Wikipedia

Of course, the data supporting global warming are quite well-established now, as this graph from Wikipedia helps to illustrate. Please see their article on global warming for more information. But despite the wealth of evidence, not everyone is convinced. The other day, while browsing blog entries categorized as science here at wordpress.com, I came across a blog entry in which the author apparently discounts global warming, oddly enough, because of the abundant evidence. Without commenting on that logic, I’d like to point out what I thought was the most interesting part of the entry, in which the author speculates why people don’t believe these are random fluctuations (emphasis mine):

…no one ever listens to that theory. Why? Probably because its not as exciting as the end of the world.

This is quite a common perception, and I don’t fault the author for writing it (though I could not resist leaving a comment). It is true that several examples have been cited as possible effects of global warming; for instance, a large outbreak of food poisoning from Vibrio parahaemolyticus (gastroenteritis) in the United States appears to be due to rising ocean temperatures (reference: McLaughlin et al. “Outbreak of Vibrio parahaemolyticus Gastroenteritis Associated with Alaskan Oysters.” New England Journal of Medicine. 353: 1463–1470 — see abstract). However, while the world as we know it may end, other ecological disasters would probably be needed for humanity’s complete eradication. And even if that were to happen, the world itself will go on just fine without us. We’ve only been on Earth for a tiny fraction of its existence—if Earth’s lifetime is one day, then Homo sapiens evolved around 2 seconds ago. Or put another way, dinosaurs were dominant on Earth for some 100 million years; they went extinct 65 million years ago, whereas Homo sapiens originated perhaps a couple hundred millennia ago, making the dinosaurs’ tenure some five hundred times longer. And of course, human civilization is only five thousand years old, only one-fortieth of our existence.

Nicely illustrating this transience is a short film entitled “Das Rad” (The Wheel, in German with English subtitles). It was nominated for best short film in the 2003 Academy Awards. It’s a very creative look at the progress of humanity from the point of view of two rocks on a hillside. It’s quite amusing. The film is approximately eight-and-a-half minutes long. From Google Video:

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