November 13, 2006, 9:07 PM CT

Where Chimp And Human Brains Diverge

Six million years ago, chimpanzees and humans diverged from a common ancestor and evolved into unique species. Now UCLA researchers have identified a new way to pinpoint the genes that separate us from our closest living relative and make us uniquely human. The Proceedings of the National Academy of Sciences reports the study in its Nov. 13 online edition.

"We share more than 95 percent of our genetic blueprint with chimps," explained Dr. Daniel Geschwind, principal investigator and Gordon and Virginia MacDonald Distinguished Professor of Human Genetics at the David Geffen School of Medicine. "What sets us apart from chimps are our brains: homo sapiens means 'the knowing man.'

"During evolution, changes in some genes altered how the human brain functions," he added. "Our research has identified an entirely new way to identify those genes in the small portion of our DNA that differs from the chimpanzee's." .

By evaluating the correlated activity of thousands of genes, the UCLA team identified not just individual genes, but entire networks of interconnected genes whose expression patterns within the brains of humans varied from those in the chimpanzee.

"Genes don't operate in isolation each functions within a system of related genes," said first author Michael Oldham, UCLA genetics researcher. "If we examined each gene individually, it would be similar to reading every fifth word in a paragraph you don't get to see how each word relates to the other. So instead we used a systems biology approach to study each gene within its context." .........

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November 10, 2006, 4:15 AM CT

Audio Telescope Heeds Call Of The Wild Birds

Scientists at the National Institute of Standards and Technology (NIST), Intelligent Automation, Inc. (Rockville, Md.) and the University of Missouri-Columbia have modified a NIST-designed microphone array to make an "audio telescope" that could help airports more efficiently avoid costly and hazardous bird-aircraft collisions by locating and identifying birds by their calls. The prototype system was described in a recent paper.*.

From chirps to trills, bird song commonly is soothing and restful--unless you're a pilot. Collisions with birds in flight, called "bird strikes," caused over $2 billion worth of damage to aircraft in the United States or U.S. aircraft abroad, since 1990, as per statistics from the Federal Aviation Administration. Worldwide, wildlife strikes --mostly birds--have destroyed more than 163 aircraft and killed more than 194 people since 1988.

Airports fight back with X-band radar and infrared cameras to monitor birds, but neither technology can distinguish between different kinds of birds, especially in bad weather. That's important because not all birds are equally hazardous to aircraft, and shutting down runways because of the proximity of unknown birds imposes its own costs in delays and increased aircraft congestion. The "audio telescope" proposed by NIST and IAI scientists is a one-meter-diameter concentric array of 192 microphones that would be mounted parallel to the ground to listen to the skies. By comparing the arrival time of sounds at different microphones, the array can determine the direction from which the sound came, even distinguishing simultaneous sounds coming from different directions. The scientists adapted mathematical algorithms designed to allow speech recognition systems to identify different speakers in order to distinguish different species by their calls. The system can tell a Canada goose from a gull or a hawk within a couple of seconds.........

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November 10, 2006, 4:10 AM CT

Sea Urchin Genome And Human Genome

The Sea Urchin Genome Sequencing Project (SUGSP) Consortium, led by the Human Genome Sequencing Center at Baylor College of Medicine (BCM-HGSC) in Houston, announced recently the decoding and analysis of the genome sequence of the sea urchin, Strongylocentrotus purpuratus.

The genome of a male California purple sea urchin was sequenced, and it contained over 814 million letters, spelling out 23,300 genes. Nearly 10,000 of the genes were scrutinized by an international consortium of 240 researchers from over 70 institutions in 11 countries. The high quality "draft" sequence covers over 90 percent of the genome. The primary results are presented in the Nov. 10 issue of Science, and 41 companion manuscripts describing further detailed analyses are contained in Science and a special issue of Developmental Biology appearing on Dec. 1.

The BCM-HGSC generated the sequence data for the SUGSP, then assembled the genome and led the analysis consortium. Additional resources for the project included a BAC library (clones with very large pieces of DNA) prepared at the California Institute of Technology and a physical map prepared at the Michael Smith Genome Sciences Centre at the British Columbia Cancer Agency in Vancouver.

The project was led by Drs. Erica Sodergren and George Weinstock, a husband and wife team at the BCM-HGSC, along with Dr. Richard Gibbs, director of the BCM-HGSC, and Drs. Eric Davidson and Andrew Cameron of the California Institute of Technology. The National Human Genome Research Institute of the National Institutes of Health provided most of the funding for the SUGSP.........

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November 7, 2006, 10:38 PM CT

Two Nerve Cells in Direct Contact

For the first time, scientists at the Max Planck Institute for Neurobiology in Martinsried near Munich have been able to show how two nerve cells communicate with each other from different hemispheres in the visual centre. This astoundingly simple circuit diagram could at a later date provide a model for algorithms to be deployed in technical systems (Nature Neuroscience).

Movements in space create in humans and animals so-called optical flow fields which are characteristic for the movement in question. In a forward movement, the objects flow by laterally, objects at the front increase in size and objects further away hardly change at all. At a higher level in the visual centre in the brain, there must be a computation of the visual information, so that animals can differentiate between their own movement and movement of their environment and are able to correct their course if necessary. It is important for the analysis of flow fields that the movement information from both eyes is merged so that the whole flow field can be assessed. In their current study, Karl Farrow, Jürgen Haag and Alexander Borst have for the first time proved the direct link between two nerve cells, one in each half of the brain, combining the movement signals from both the facetted eyes of a fly.........

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November 1, 2006, 7:48 PM CT

A Biomaterial Blend Library

From dental implants to hip replacements, biomaterials have become big business. But researchers pursuing this modern medical revolution share a basic challenge: biocompatibility. How will a biomaterial on the lab bench actually work inside the human body? Will a patient accept the new material or suffer an inflammatory response? And can that material survive in a human's complex system?

To tackle such questions, scientists at the National Institute of Standards and Technology (NIST) and the New Jersey Center for Biomaterials (NJCB) at Rutgers University have developed new methods to analyze the interactions between cells and biomaterials. Their work could lead to inexpensive techniques for building better biomaterials.

Polymers derived from the amino acid tyrosine make up a broad class of degradable biomaterials under investigation. Such materials provide a temporary scaffold for cells to grow and tissue to regenerate. In a 2006 study* presented at the national meeting of the American Chemical Society in September, the scientists analyzed how two types of model cells-immune cells known as macrophages and bone cells known as osteoblasts-responded to changes in the composition of thin films made of these tyrosine-derived polymers. In practice, a number of biomaterials are made from blends of polymers to achieve specific material properties. Optimizing the blend composition is often a difficult and time-consuming task. As the blends gained a higher or lower proportion of a respective material, the cells around them react by changing shape, ultimately increasing or decreasing contact with the films. In the body, such cell-material dynamics are critically important to the outcome-determining whether a biomaterial leads to inflammation or abnormal cell growth, for example.........

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November 1, 2006, 4:18 PM CT

Old Leaves Need To Die In Time

In a study from the recent issue of The American Naturalist, scientists Alex Boonman and co-workers from the Netherlands show that it is beneficial for plants growing in a dense stand to shed their oldest, lower leaves once these become shaded. By using transgenic tobacco plants that do not shed their lower leaves, they were able to show that shaded old leaves become a burden to a plant because they no longer photosynthesize but still require energy to be maintained.

Moreover, the nutrients in these leaves can be more usefully employed by the plant when re-allocated to new leaves at the top of the canopy, where more light is available and higher photosynthetic rates can be attained. Previously, theoretical modeling has been extensively used to investigate how plants should distribute their leaf area and nutrients to maximize their photosynthesis and fitness. However, a direct experimental test was lacking till now.

"Keeping up with the neighbors is important for plants in leaf canopies" Alex Boonman states, "because failure to project enough leaf area at the top of the canopy means that some other plant will do it, with shading and therefore diminished photosynthesis as the consequence." The transgenics, which were originally developed by Susheng Gan and Richard Amasino at the University of Wisconsin, indeed produced less leaf area in the upper canopy layer than normal plants and performed less well in competition exeriments.........

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November 1, 2006, 4:10 PM CT

Floating Lovers Count Too

In a paper from the recent issue of The American Naturalist, Vincenzo Penteriani, Fermin Otalora, and Miguel Ferrer, researchers at the Estacion Biologica de Donana (Consejo Superior de Investigaciones Científicas, Spain), focus on the forgotten and invisible side of animal populations - the floaters. Floaters are dispersed individuals who enter the reproductive population when breeding territory or a potential mate become available.

The researchers' work has shown that factors affecting the survival of floaters within their settlement areas may directly influence the dynamics of the whole population. Vincenzo Penteriani, Fermin Otalora, and Miguel Ferrer looked at population data for the Spanish imperial eagle Aquila adalberti over the last century. With less than 150 pairs in the whole Iberian Peninsula, this eagle is one of the most threatened raptors in the world. They found that extremely high mortalities of floaters in settlement areas cause a decrease in the number of breeders, due to the increasing difficulty of breeding pair formation and, consequently, a positive density-fecundity relationship in the breeding portion of the population.

The results support the novel idea that taking floater dynamics within settlement areas into consideration can illuminate inexplicable positive density-dependent patterns in breeding populations. "Population studies that ignore floater dynamics may fail to understand all the different factors influencing density-dependent population patterns," Penteriani says. He continues, "Clearly defining the portion of the population that shapes density-dependent patterns may help to solve some of the ambiguities that, after some seventy years of debate, still surround density-dependence and population dynamics in general".........

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October 31, 2006, 4:57 AM CT

Grasslands To Go Native

Montana rancher and inventor Lee Arbuckle may soon change the nation's market for native grass seed, a tricky-to-harvest crop worth hundreds of millions and vital to restoring wildlands.

With the help of the Montana Manufacturing Extension Center at Montana State University, Arbuckle and his wife Maggie have spent the last five years researching and developing a native grass seed harvester. The Arbuckle Native Seedster will be manufactured in Billings, with the first one on the market in 2007.

"We're going to change the economics of the native grass seed industry," Arbuckle said. "The Seedster isn't a combine or a stripper, but a new-fangled plucker. This harvester isn't a better mousetrap; it's the first one".

Native grass seed is a growing market. Federal, state and local governments purchase large amounts of native seed, as do ranchers and landscapers. Such seed produces grasses that are prized for their drought and wildfire resistance, ability to stabilize eroding soil, desirability as forage and reseeding capacity. Much of the seed market is for the restoration of lands disturbed by mining, road construction and fires.

The Plant Materials Program of the U.S. Department of Agriculture estimated that in 2001 more than 19 million pounds of PMP released varieties of native seed species sold for $94 million, representing only a fraction of the market.........

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October 31, 2006, 4:21 AM CT

Insights Into Spiders' Polymer Art

A team of MIT engineers has identified two key physical processes that lend spider silk its unrivaled strength and durability, bringing closer to reality the long-sought goal of spinning artificial spider silk.

Manufactured spider silk could be used for artificial tendons and ligaments, sutures, parachutes and bulletproof vests. But engineers have not managed to do what spiders do effortlessly.

According to a research findings published in the recent issue of the Journal of Experimental Biology, Gareth H. McKinley, professor of mechanical engineering, and colleagues examined how spiders spin their native silk fibers, with hopes of ultimately reproducing the process artificially.

McKinley heads the Non-Newtonian Fluid Dynamics research group in MIT's Department of Mechanical Engineering. Non-Newtonian fluids behave in strange and unexpected ways because their viscosity, or consistency, changes with both the rate and the total amount of strain applied to them.

Spider silk is a protein solution that undergoes pronounced changes as part of the spinning process. Egg whites, another non-Newtonian fluid, change from a watery gel to a rubbery solid when heated. Spider silk, it turns out, undergoes similar irreversible physical changes.

Stickiness and Flow........

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October 29, 2006, 8:01 PM CT

See What A Three-legged Tortoise Got

Tina the tortoise has been given a lift after being fitted with a suspension system and a pneumatic tyre to help her cope with muddy terrain.

The three-legged reptile can now go off-road after the 4-4-style system was attached to her shell.

Tina was fitted with a plastic wheel four years ago to replace her rear right leg.

But our increasingly warmer autumns mean Tina hibernates later in the year, leaving her battling to cope with muddy grass and slopes and dead leaves.

So the rudimentary wheel has now been replaced with an air-filled tyre and a spring suspension system with shock absorber.

From Metro.co.uk.........

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