Science News Update (30 Nov 2006)

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).

Continue reading “Science News Update (30 Nov 2006)”

Video Games as an Anti-Obesity Tool?

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.

Continue reading “Video Games as an Anti-Obesity Tool?”

New Horizons Sights Pluto

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) Continue reading New Horizons Sights Pluto”

Further Developments in Litvinenko’s Polonium-210 Poisoning

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

Learning to Walk

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

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 (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

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.

Continue reading “Learning to Walk”

Artificial Sun

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.

Continue reading “Artificial Sun”

Family Circle

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.

Continue reading “Family Circle”