January 30, 2007, 4:48 AM CT

Vaginal Birth Increases Risk Of Brain Hemorrhage

The first researchers to use magnetic resonance imaging (MRI) to study the brains of a large group of babies soon after birth found a small amount of bleeding in and around the brains of one in four babies who were delivered vaginally. The study appears in the recent issue of Radiology.

"Small bleeds in and around the brain are very common in infants who are born vaginally," said John H. Gilmore, M.D., professor of psychiatry and Vice-Chair for Research and Scientific Affairs at the University of North Carolina School of Medicine in Chapel Hill. "It seems that a normal vaginal birth can cause these small bleeds".

For the study, 88 asymptomatic infants, equally divided between male and female, underwent MRI between the ages of one and five weeks. Sixty-five had been delivered vaginally and 23 had been delivered by cesarean section. MR images showed that 17 (26 percent) of the babies who had been delivered vaginally had intracranial hemorrhages (ICH), or small bleeds in and around the brain. Seven infants had two or more types of ICH. Prior studies have shown a smaller incidence-approximately 10 percent-of intracranial hemorrhage associated with vaginal birth.

While ICH was significantly associated with vaginal birth, it was not dependent on prolonged duration of labor or on traumatic or assisted vaginal birth.........

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January 30, 2007, 4:37 AM CT

Dig Deeper To Find Martian Life

Probes designed to find life on Mars do not drill deep enough to find the living cells that scientists believe may exist well below the surface of Mars, according to research led by UCL (University College London). Although current drills may find essential tell-tale signs that life once existed on Mars, cellular life could not survive the radiation levels for long enough any closer to the surface of Mars than a few metres deep - beyond the reach of even state-of-the-art drills.

The study, published in the journal 'Geophysical Research Letters' (GRL), maps out the cosmic radiation levels at various depths, taking into account different surface conditions on Mars, and shows that the best place to look for living cells is within the ice at Elysium, the location of the newly discovered frozen sea on Mars.

The lead author, Lewis Dartnell, UCL Centre for Mathematics and Physics in the Life Sciences & Experimental Biology (CoMPLEX), said: "Finding hints that life once existed - proteins, DNA fragments or fossils - would be a major discovery in itself, but the Holy Grail for astrobiologists is finding a living cell that we can warm up, feed nutrients and reawaken for studying.

"It just isn't plausible that dormant life is still surviving in the near-subsurface of Mars - within the first couple of metres below the surface - in the face of the ionizing radiation field. Finding life on Mars depends on liquid water surfacing on Mars, but the last time liquid water was widespread on Mars was billions of years ago. Even the hardiest cells we know of could not possibly survive the cosmic radiation levels near the surface of Mars for that long".........

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January 28, 2007, 9:44 PM CT

Improving Energy Efficiency Of Ethanol Production

Carnegie Mellon University Chemical Engineers have devised a new process that can improve the efficiency of ethanol production, a major component in making biofuels a significant part of the U.S. energy supply.

Carnegie Mellon researchers have used advanced process design methods combined with mathematical optimization techniques to reduce the operating costs of corn-based bio-ethanol plants by more than 60 percent.

The key to the Carnegie Mellon strategy involves redesigning the distillation process by using a multi-column system together with a network for energy recovery that ultimately reduces the consumption of steam, a major energy component in the production of corn-based ethanol.

"This new design reduces the manufacturing cost for producing ethanol by 11 percent, from $1.61 a gallon to $1.43 a gallon,'' said Chemical Engineering Professor Ignacio E. Grossmann, who completed the research with graduate students Ramkumar Karuppiah, Andreas Peschel and Mariano Martin. "This research also is an important step in making the production of ethanol more energy efficient and economical.''.

For a long time, corn-based ethanol was considered a questionable energy resource. Today, 46 percent of the nation's gasoline contains some percentage of ethanol. And demand is driven by a federal mandate that 5 percent of the nation's gasoline supply - roughly 7.5 billion gallons - contain some ethanol by 2012.........

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January 24, 2007, 7:53 PM CT

New Species Of Distinctive Cloud-forest Rodent

A strikingly unusual animal was recently discovered in the cloud-forests of Peru. The large rodent is about the size of a squirrel and looks a bit like one, except its closest relatives are spiny rats.

The nocturnal, climbing rodent is beautiful yet strange looking, with long dense fur, a broad blocky head, and thickly furred tail. A blackish crest of fur on the crown, nape and shoulders add to its distinctive appearance.

Isothrix barbarabrownae, as the new species has been named, is described in the current issue of Mastozoología Neotropical (Neotropical mammalogy), the principal mammalogy journal of South America. A color illustration of the bushy rodent graces the cover of the journal. It and another color illustration of the new species are both available to the media.

The authors of the study found the rodent in 1999 while conducting field research in Peru's Manu National Park and Biosphere Reserve Mountains in Southern Peru along the eastern slope of the Andes. Extending from lowland tropical forests in the Amazon Basin to open grasslands above the Andean tree line, Manu is home to more species of mammals and birds than any equivalently sized area in the world.

"Like other tropical mountain ranges, such as the Himalayas, Ruwenzoris, Virungas and Kinabalu, the Andes support a fantastic variety of habitats," said Bruce Patterson, MacArthur Curator of Mammals at The Field Museum. "These in turn support some of the richest faunas on the planet".........

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January 24, 2007, 7:33 PM CT

The jet stream of Titan

A pair of rare celestial alignments that occurred in November 2003 helped an international team of astronomers investigate the far-off world of Titan. In particular, the alignments helped validate the atmospheric model used to design the entry trajectory for ESA's Huygens probe.

Now the unique results are helping to place the descent of Huygens in a global context, and to investigate the upper layers of Titan's atmosphere.

Occasionally Titan passes directly in front of a distant star. When it does so, the light from the star is blocked out. Because Titan has a thick atmosphere, the light does not 'turn off' straight away. Instead, it drops gradually as the blankets of atmosphere slide in front of the star. The way the light drops tells astronomers about the atmosphere of Titan.

By pure chance on 14 November 2003, fourteen months before Huygens' historic descent through Titan's atmosphere, Titan passed in front of two stars, just seven and a half hours apart. Bruno Sicardy, Observatoire de Paris, France, organised expeditions to record the occultations, as such events are called.

The first occultation was visible just after midnight from the Indian Ocean and the southern half of Africa. The second could be seen from Western Europe, the Atlantic Ocean, Northern and Central Americas. Teams of astronomers set up along the occultation tracks.........

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January 24, 2007, 5:55 PM CT

The Sun May Have A Dimmer Switch

THERE'S a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100,000 years - exactly the same period as between ice ages on Earth. So says a physicist who has created a computer model of our star's core.

Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled the effect of temperature fluctuations in the sun's interior. As per the standard view, the temperature of the sun's core is held constant by the opposing pressures of gravity and nuclear fusion. However, Ehrlich believed that slight variations should be possible.

He took as his starting point the work of Attila Grandpierre of the Konkoly Observatory of the Hungarian Academy of Sciences. In 2005, Grandpierre and a collaborator, Gábor Ágoston, calculated that magnetic fields in the sun's core could produce small instabilities in the solar plasma. These instabilities would induce localised oscillations in temperature.

Ehrlich's model shows that whilst most of these oscillations cancel each other out, some reinforce one another and become long-lived temperature variations. The favoured frequencies allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years. Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other.........

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January 17, 2007, 8:12 PM CT

Training Your Breathing Muscles To Improves Swimming

Swimmers and scuba divers can improve their swimming endurance and breathing capacity through targeted training of the respiratory muscles, researchers at the University at Buffalo have shown.

In this pioneering work, subjects who followed a resistance-breathing training protocol (breathing load) improved their respiratory muscle strength and their snorkel swimming time by 33 percent and underwater scuba swimming time by 66 percent, compared to their baseline values. Participants randomized to a similar protocol requiring high respiratory flow rates (endurance) improved their respiratory endurance and surface and underwater swimming times by 38 percent and 26 percent, respectively.

The group randomized to a placebo training program, conducted with the same equipment and protocol, showed no significant improvement in respiratory or swimming performance.

Results of the study, conducted in UB's Center for Research and Education in Special Environments (CRESE) appeared in the December online issue of the European Journal of Applied Physiology and will appear in printnext month.

"Specific respiratory muscle training could allow divers in the military, civilian rescue services, commercial enterprises and sport to perform better underwater," said Claes E.G. Lundgren, M.D., Ph.D., professor of physiology and biophysics in the UB School of Medicine and Biomedical Sciences and the study's senior author.........

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January 16, 2007, 8:21 PM CT

Big Vegetarian Mammals And Ecosystems

Removing large herbivorous mammals from the African savanna can cause a dramatic shift in the relative abundance of species throughout the food chain, according to scientists from Stanford University, Princeton University and the University of California-Davis. Their findings were published in the Jan. 2 edition of Proceedings of the National Academy of Sciences (PNAS).

In the study, the research team used large electric fences to exclude cattle, elephants, zebras and other herbivorous mammals from experimental plots on a ranch in central Kenya from May 2004 to December 2005. During that time, the scientists monitored changes in the populations of trees, beetles, lizards and other plant and animal species.

"All of the species studied increased in abundance in the absence of large plant-eating mammals," said lead author Robert Pringle, a graduate student in the Department of Biological Sciences at Stanford. These results are examples of what ecologists call cascading effects, he added.

Although elephants and zebras do not interact directly with insects, they share plants as a food source, Pringle noted. Previous studies have shown that when elephants and zebras are experimentally removed or hunted out, plant matter accumulates and insect populations increase.........

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January 11, 2007, 9:23 PM CT

Spread Of Modern Humans Occurred Later

The spread of modern humans out of Africa occurred 40,000 to 50,000 years later than previously thought, according to researchers including one Texas A&M University anthropologist.

Ted Goebel, associate director of the Center for the Study of the First Americans at Texas A&M, is the author of the paper titled "The Missing Years for Modern Humans" that appears in the Jan. 12 (Friday) issue of Science.

Goebel's paper is one of three published in the current issue of Science dealing with the origins and dispersals of modern humans during the Ice Age. A fourth paper appeared in a previous issue of the journal.

The other papers are written by human paleontologist Frederick Grine of Stony Brook University, geneticist Annamaria Olivieri from the University of Pavia in Italy, and archeologists Michael Anikovich and Andre Sinitsyn of the Russian Academy of Science and John Hoffecker of the University of Colorado.

"All of them have one thing in common," says Goebel of the papers. "They are all trying to investigate and demonstrate when it was that modern humans evolved in Africa, left Africa and colonized different areas of the Old World".

Previous theories held that modern humans spread from Africa 100,000 years ago. New data, however, suggest that their migration occurred only 50,000 to 60,000 years ago, Goebel argues. Additionally, the spread of modern humans in eastern Europe and Russia occurred earlier than previously thought notes Goebel.........

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January 11, 2007, 7:53 PM CT

Fixing The Nitrogen Balance

Researchers in the US have found that, reassuringly, the global nitrogen cycles can be more easily balanced out than previously thought, as sources and sinks of usable nitrogen are geographically close and respond to each other in rapid feedback.

Conventional wisdom in biogeochemistry suggested that most of the nitrogen fixation in the oceans was going on in the Atlantic, where the supply of iron, required by the nitrogenase enzyme, is more plentiful. However, the evidence also suggested that most of the loss of fixed nitrogen (denitrification) occurred in the Pacific. With such a vast distance between producers and consumers, the equilibrium between the two processes might have taken millennia to adjust to changes in environmental conditions, such as the current climate change.

Curtis Deutsch from the University of Washington at Seattle, together with colleagues from four other institutions across the US, has developed a new way of analysing the existing data on nitrogen cycles, based on the parameter P*, which describes the relative excess or lack of phosphate ions with respect to the predicted ratio between N and P consumption (normally 16:1).

Deutsch and colleagues now conclude that inhabitants of the Pacific Ocean are responsible for around two thirds of the total nitrogen fixation that occurs annually in the oceans (estimated to be 140 million tons). The Atlantic contributes less than 20 per cent. Thus, the sources and sinks of usable nitrogen are geographically closer than anticipated. Furthermore, the analysis suggests that the supply of iron from the continents is not the limiting factor for nitrogenase activity. Instead, it looks as though nitrogen fixation is encouraged by a shortage of nitrate in a negative feedback loop, which stabilises the overall nitrogen balance of our planet.........

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