Making Science More Better For You on 01/29/08

Headlines of the day
Poor workers' kidneys stolen, sold to rich (CNN)

Deejay sets fire to radio station after his songs aren't played (the obscure store)

Illegal aliens rear end homeland security vehicle (KTAR.com)

It just looks like we’re doing nothing. We’re actually quite busy.

Sedentary Lifestyles Associated With Accelerated Aging Process

ScienceDaily (Jan. 29, 2008) — Individuals who are physically active during their leisure time appear to be biologically younger than those with sedentary lifestyles, according to a report in the January 28 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Regular exercisers have lower rates of cardiovascular disease, type 2 diabetes, cancer, high blood pressure, obesity and osteoporosis, according to background information in the article. "A sedentary lifestyle increases the propensity to aging-related disease and premature death," the authors write. "Inactivity may diminish life expectancy not only by predisposing to aging-related diseases but also because it may influence the aging process itself."

Lynn F. Cherkas, Ph.D., of King's College London, and colleagues studied 2,401 white twins, administering questionnaires on physical activity level, smoking habits and socioeconomic status. The participants also provided a blood sample from which DNA was extracted. The researchers examined the length of telomeres--repeated sequences at the end of chromosomes--in the twins' white blood cells (leukocytes). Leukocyte telomeres progressively shorten over time and may serve as a marker of biological age.

Telomere length decreased with age, with an average loss of 21 nucleotides (structural units) per year. Men and women who were less physically active in their leisure time had shorter leukocyte telomeres than those who were more active. "Such a relationship between leukocyte telomere length and physical activity level remained significant after adjustment for body mass index, smoking, socioeconomic status and physical activity at work," the authors write. "The mean difference in leukocyte telomere length between the most active [who performed an average of 199 minutes of physical activity per week] and least active [16 minutes of physical activity per week] subjects was 200 nucleotides, which means that the most active subjects had telomeres the same length as sedentary individuals up to 10 years younger, on average." A sub-analysis comparing pairs in which twins had different levels of physical activity showed similar results.

Oxidative stress--damage caused to cells by exposure to oxygen--and inflammation are likely mechanisms by which sedentary lifestyles shorten telomeres, the authors suggest. In addition, perceived stress levels have been linked to telomere length. Physical activity may reduce psychological stress, thus mitigating its effect on telomeres and the aging process.

"The U.S. guidelines recommend that 30 minutes of moderate-intensity physical activity at least five days a week can have significant health benefits," the authors write. "Our results underscore the vital importance of these guidelines. They show that adults who partake in regular physical activity are biologically younger than sedentary individuals. This conclusion provides a powerful message that could be used by clinicians to promote the potential anti-aging effect of regular exercise."


"Persons who exercise are different from sedentary persons in many ways, and although certain variables were adjusted for in this analysis, many additional factors could be responsible for the biological differences between active and sedentary persons, a situation referred to by epidemiologists as residual confounding," Dr. Guralnik writes. "Nevertheless, this article serves as one of many pieces of evidence that telomere length might be targeted in studying aging outcomes."


That cheer you just heard was from the adult entertainment industry

New Experimental Website Converts Photos Into 3D Models


ScienceDaily (Jan. 28, 2008) — An artist might spend weeks fretting over questions of depth, scale and perspective in a landscape painting, but once it is done, what's left is a two-dimensional image with a fixed point of view. But the Make3d algorithm, developed by Stanford computer scientists, can take any two-dimensional image and create a three-dimensional "fly around" model of its content, giving viewers access to the scene's depth and a range of points of view.

"The algorithm uses a variety of visual cues that humans use for estimating the 3-D aspects of a scene," said Ashutosh Saxena, a doctoral student in computer science who developed the Make3d website with Andrew Ng, an assistant professor of computer science. "If we look at a grass field, we can see that the texture changes in a particular way as it becomes more distant."

The applications of extracting 3-D models from 2-D images, the researchers say, could range from enhanced pictures for online real estate sites to quickly creating environments for video games and improving the vision and dexterity of mobile robots as they navigate through the spatial world.

Extracting 3-D information from still images is an emerging class of technology. In the past, some researchers have synthesized 3-D models by analyzing multiple images of a scene. Others, including Ng and Saxena in 2005, have developed algorithms that infer depth from single images by combining assumptions about what must be ground or sky with simple cues such as vertical lines in the image that represent walls or trees. But Make3d creates accurate and smooth models about twice as often as competing approaches, Ng said, by abandoning limiting assumptions in favor of a new, deeper analysis of each image and the powerful artificial intelligence technique "machine learning."

Restoring the third dimension

To "teach" the algorithm about depth, orientation and position in 2-D images, the researchers fed it still images of campus scenes along with 3-D data of the same scenes gathered with laser scanners. The algorithm correlated the two sets together, eventually gaining a good idea of the trends and patterns associated with being near or far. For example, it learned that abrupt changes along edges correlate well with one object occluding another, and it saw that things that are far away can be just a little hazier and more bluish than things that are close.

To make these judgments, the algorithm breaks the image up into tiny planes called "superpixels," which are within the image and have very uniform color, brightness and other attributes. By looking at a superpixel in concert with its neighbors, analyzing changes such as gradations of texture, the algorithm makes a judgment about how far it is from the viewer and what its orientation in space is. Unlike some previous algorithms, the Stanford one can account for planes at any angle, not just horizontal or vertical. This allows it to create models for scenes that have planes at many orientations, such as the curved branches of trees or the slopes of mountains.

On the Make3d website, the algorithm puts images uploaded by users into a processing queue and will send an e-mail when the model has been rendered. Users can then vote on whether the model looks good, and can see an alternative rendering and even tinker with the model to fix what might not have been rendered right the first time.

Photos can be uploaded directly or pulled into the site from the popular photo-sharing site Flickr.

Although the technology works better than any other has so far, Ng said, it is not perfect. The software is at its best with landscapes and scenery rather than close-ups of individual objects. Also, he and Saxena hope to improve it by introducing object recognition. The idea is that if the software can recognize a human form in a photo it can make more accurate distance judgments based on the size of the person in the photo.

A paper on the algorithm by Ng, Saxena and a fellow student, Min Sun, won the best paper award at the 3-D recognition and reconstruction workshop at the International Conference on Computer Vision in Rio de Janeiro in October 2007.

For many panoramic scenes, there is still no substitute for being there. But when flat photos become 3-D, viewers can feel a little closer—or farther. The algorithm runs at http://make3d.stanford.edu.

Can you say Silver Surfer? Sure you can.

Hyperfast Star Proven To Be Alien

ScienceDaily (Jan. 29, 2008) — A young star is speeding away from the Milky Way so fast that astronomers have been puzzled by where it came from; based on its young age it has traveled too far to have come from our galaxy. Now by analyzing its velocity, light intensity, and for the first time its tell-tale elemental composition, Carnegie astronomers Alceste Bonanos and Mercedes López-Morales, and collaborators Ian Hunter and Robert Ryans from Queen's University Belfast have determined that it came from our neighboring galaxy, the Large Magellanic Cloud (LMC). The result suggests that it was ejected from that galaxy by a yet-to-be-observed massive black hole.

The star, dubbed HE 0437-5439, is an early-type star and one of ten so-called hypervelocity stars so far found speeding away from the Milky Way. "But this one is different from the other nine," commented López-Morales. "Their type, speed, and age make them consistent with having been ejected from the center of our galaxy, where we know there is a super-massive black hole. This star, discovered in 2005*, initially appeared to have an elemental makeup like our Sun's, suggesting that it, too, came from the center of our galaxy. But that didn't make sense because it would have taken 100 million years to get to its location, and HE 0437-5439 is only 35 million years old."

To explain the enigma, or "paradox of youth," the discoverers proposed that HE 0437-5439 was either a so-called blue straggler--a relatively young, massive star resulting from the merger of two low-mass stars from the Milky Way, or it originated from the Large Magellanic Cloud.

"We were intrigued by the conundrum and decided to take up the challenge to solve this," stated Bonanos. "Stars in the LMC are known to have lower elemental abundances than most stars in our galaxy, so we could determine if its chemistry was more like that galaxy's or our own."

The team confirmed results of the previous study concerning the mass, age, and speed of the star. It is about nine times the mass of our Sun, about 35 million years old, and it is zooming away from the Milky Way and Large Magellanic Cloud into intergalactic space at 1.6 million miles per hour (2.6 million km/hour).

Although the previous study was able to roughly estimate the star's elemental composition, the measurements were not detailed enough to determine if the elements match stars in our galaxy, or are characteristic of stars from the Large Magellanic Cloud. These astronomers were able to measure the relative abundances of certain elements for the first time in any hypervelocity star. The relative abundance of key elements tells them where a star originated.

"We've ruled out that the star came from the Milky Way," explained Bonanos. "The concentration of elements in Large Magellanic Cloud stars are about half those in our Sun. Like evidence from a crime scene, the fingerprints point to an origin in the Large Magellanic Cloud."

Based on the speed of the star's rotation measured by the discoverers, and confirmed by this team, the astronomers believe that the star was originally part of a binary system. The binary could have passed close to a black hole 1,000 the mass of the Sun**. As one star was pulled into the black hole, the other was whipped into frenzy and flung out of the galaxy.

"This is the first observational clue that a massive black hole exists somewhere in the LMC. We look forward to finding out where this black hole might be," concluded Bonanos.


Earth’s creamy nougat center revealed

Earth's Getting 'Soft' In The Middle, Geologists Note

ScienceDaily (Jan. 28, 2008) — A new study suggests that material in part of the lower mantle has unusual electronic characteristics that make sound propagate more slowly, suggesting that the material there is softer than previously thought. The results call into question the traditional techniques for understanding this region of the planet.

Since we can't sample the deepest regions of the Earth, scientists watch the velocity of seismic waves as they travel through the planet to determine the composition and density of that material. Now a new study suggests that material in part of the lower mantle has unusual electronic characteristics that make sound propagate more slowly, suggesting that the material there is softer than previously thought. The results call into question the traditional techniques for understanding this region of the planet.

The lower mantle extends from about 400 miles to 1800 miles (660-2900 kilometers) into Earth and sits atop the outer core. Pressures and temperatures are so brutal there that materials are changed into forms that don't exist in rocks at the planet's surface and must be studied under carefully controlled conditions in the laboratory. The pressures range from 230,000 times the atmospheric pressure at sea level (23 GPa), to 1.35 million times sea-level pressure (135 GPa). And the heat is equally extreme--from about 2,800 to 6,700 degrees Fahrenheit (1800K--4000K).

Iron is abundant in the Earth, and is a major component of the minerals ferropericlase and the silicate perovskite in the lower mantle. In previous work, researchers found that the outermost electrons of iron in ferropericlase are forced to pair up under the extreme pressures creating a so-called spin-transition zone within the lower mantle.

"What happens when unpaired electrons--called a high-spin state--are forced to pair up is that they transition to what is called a low-spin state. And when that happens, the conductivity, density, and chemical properties change," explained Goncharov. "What's most important for seismology is the acoustic properties--the propagation of sound. We determined the elasticity of ferropericlase through the pressure-induced high-spin to low-spin transition. We did this by measuring the velocity of acoustic waves propagating in different directions in a single crystal of the material and found that over an extended pressure range (from about 395,000 to 590,000 atmospheres) the material became 'softer'--that is, the waves slowed down more than expected from previous work. Thus, at high temperature corresponding distributions will become very broad, which will result in a wide range of depth having subtly anomalous properties that perhaps extend through most of the lower mantle."

The results suggest that scientists may have to go back to the drawing board to model this region of the Earth.

Some say getting soft in the middle is a function of age.