December 11, 2006, 4:53 AM CT

Birth Pangs of Earth's Crust

Forsyth and Saal, professors of geology at Brown University, were returning from a research cruise to map an area of seafloor near the Galapagos Islands last April, along with seven Brown graduate students and four undergraduates. The cruise route took the ship right by a highly studied section of the mid-ocean ridge called the East Pacific Rise. The area had experienced an episode of seafloor spreading in 1991 and was being closely monitored as part of the RIDGE2000 program sponsored by the National Science Foundation.

A team of scientists headed by Maya Tolstoy, a geologist at Columbia's Earth Institute, had placed an array of ocean-bottom seismometers (OBS) at the spot in 2003 and collected data from the vibration-recording devices at least once a year. With ship-time at a premium, it's common for a research ship to make a quick stop to download such data.

The task should have been simple. The seismometers are anchored to the seafloor by a mechanism that will release them and allow them to float to the surface when triggered by an acoustic signal. The crew and scientists scoop up the microwave-oven-sized devices and return them to shore, replacing them with new ones that will monitor seismic activity for the next year. It's uncommon for an OBS to be lost due to mechanical malfunction.........

Posted by: Tyler      Permalink         Source

December 11, 2006, 4:48 AM CT

Finding Mind-body Connection With Fruit Fly Sex

Male fruit flies are smaller and darker than female flies. The hair-like bristles on their forelegs are shorter, thicker. Their sexual equipment, of course, is different, too.

"Doublesex" is the gene largely responsible for these body differences. Doublesex, new research shows, is responsible for behavior differences as well. The finding, made by Brown University biologists, debunks the notion that sexual mind and sexual body are built by separate sets of genes. Rather, researchers found, doublesex acts in concert with the gene "fruitless" to establish the wing-shaking come-ons and flirtatious flights that mark male and female fly courtship.

Results are published in Nature Genetics.

"What we found here, and what is becoming increasingly clear in the field, is that genetic interactions that influence behavior are more complex than we thought," said Michael McKeown, a Brown biologist who led the research. "In the case of sex-differences in flies, there isn't a simple two-track genetic system - one that shapes body and one that shapes behavior. Doublesex and fruitless act together to help regulate behavior in the context of other developmental genes".

How genes contribute to behavior, from aggression to alcoholism, is a growing and contentious area of biology. For more than a decade, McKeown has been steeped in the science, using the fruit fly as a model to understand how genes build a nervous system that, in turn, controls complex behaviors. Since humans and flies have thousands of genes in common, the work can shine a light on the biological roots of human behavior. For example, McKeown recently helped discover a genetic mutation that causes flies to develop symptoms similar to Alzheimer's disease - a gene very similar to one found in humans.........

Posted by: Ashley      Permalink         Source

December 11, 2006, 4:38 AM CT

Isotopes Score One for Traditional Theory

One great beauty of plate tectonics theory is that it explains so a number of geological phenomena at one time. But plate tectonics could not explain the location of a number of volcanic islands - Hawaii, the Azores or the Galapagos Islands, often called "hotspots" - far from the edge of tectonic plates. To deal with those observations, geologists invoked the concept of "plumes" - areas where buoyant sections of mantle material rose, melted and developed into concentrated upwellings of magma, forming seamounts and island chains.

A running battle has evolved over the last 30 years concerning hotspots: One camp claims it is not necessary to invoke mantle plumes to explain such volcanic islands, and the other camp - a sizeable portion of the geological community - supports mantle plumes as the most internally consistent explanation for a wide variety of data.

A study published this week in the journal Nature raises the bar for plume opponents by finding a close connection between modeled and observed ratios of uranium-series isotopes across eight island locations. The study strongly supports upwelling of mantle material as the source of these islands. Moreover, the detailed data allow scientists to estimate the change in temperature, speed and size of mantle plumes at the locations studied.........

Posted by: Tyler      Permalink         Source

December 10, 2006, 6:21 PM CT

Extreme Life

A host of record-breaking discoveries and revelations that stretch the extreme frontiers of marine knowledge were achieved by the Census of Marine Life in 2006, highlights of which were released recently.

They include life adapted to brutal conditions around 407ºC fluids spewing from a seafloor vent (the hottest ever discovered), a mighty microbe 1 cm in diameter, mysterious 1.8 kg (4 lb) lobsters off the Madagascar coast, a US school of fish the size of Manhattan Island, and more unfamiliar than familiar species turned up beneath 700 meters of Antarctic ice.

Now in its 6th year, Census participants and their supporters pool talents and specialties, ships and laboratories, archives and technology in an unprecedented global scientific collaboration. Together, they are systematically recording the diversity, distribution, and abundance of global marine life. The most intense field work is taking place in 2006-8; the results will be analysed and synthesized in 2009-10 with the goal by 2010 of an initial census describing what lived, now lives, and will live in the oceans.

Census scientists mounted 19 ocean expeditions in 2006 (a 20th expedition underway in the Antarctic can be followed online at www.awi.de/MET/Polarstern/psobse.html). They inventoried nearshore biodiversity, where the number of active sampling sites grew exponentially from 30 to 128 in 2006 alone. And, using satellites, they followed across thousands of kilometers of ocean more than 20 tagged species - from sharks and squid to sea lions and albatross.........

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December 10, 2006, 5:42 PM CT

Unusual Deep Sea Animals

We are all familiar with dolphins, whales and sharks; we know what tuna and snapper look like, but what about some less familiar fish such as lizardfish, giant squid, or blind eels? There are so a number of lesser known animals in the depths of the ocean that we hear little or nothing about most times, it is interesting to investigate a few of these creatures and understand them a little more.

The first on our list of deep sea creatures is the fangtooth fish. This fish is one of the most evil looking ocean predators. It lives in the deep ocean and catches its prey by luring them in with glowing light organs called photophores. In such a dark abyss, fish are attracted to the light put off by the organ and once they are close enough the fangtooth fish catches them in his numerous large teeth. He looks like an underwater vampire.

Another carnivorous sea animal is the deep-sea lizardfish. These interesting fish look almost like a short snake in water. Their mouths are covered with harpoon-tipped teeth that grasp their prey and don't let go, similar to a fish hook. These teeth are hinged so that they can flattened down when prey is going in and stand up when resisting. They don't even need to actively swallow; the struggling prey just ratchets itself inside. With their glowing yellow eyes, the lizardfish is a wonder to behold.........

Posted by: Ashley      Permalink         Source

December 8, 2006, 4:51 AM CT

Mood Makes Food Taste Different

Feeling anxious? Your mood may actually change how your dinner tastes, making the bitter and salty flavours recede, as per new research.

This link between the chemical balance in your brain and your sense of taste could one day help doctors to treat depression. There are currently no on-the-spot tests for deciding which medicine will work best in individual patients with this condition. Scientists hope that a test based on flavour detection could help doctors to get more prescriptions right first time.

It has long been known that people who are depressed have lower-than-usual levels of the brain chemicals serotonin or noradrenaline, or in some cases both. A number of also have a blunted sense of taste, which is presumably caused by changes in brain chemistry.

To unpick the relationship between the two, Lucy Donaldson and her colleagues at the University of Bristol, UK, gave 20 healthy volunteers two antidepressant drugs, and checked their sensitivity to different tastes. The drug that raised serotonin levels made people more sensitive to sweet and bitter tastes, the team reports in the Journal of Neuroscience1. The other, which increased noradrenaline, enhanced recognition of bitter and sour tastes.

In healthy people, volunteers whose anxiety levels were naturally higher were less sensitive to bitter and salty tastes.........

Posted by: Sean      Permalink         Source

December 7, 2006, 9:58 PM CT

New Approach To Melanoma Treatment

While investigating a fungus known to cause an infection in people with AIDS, two grantees of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), unexpectedly discovered a potential strategy for treating metastatic melanoma, one of the deadliest forms of skin cancer. The treatment approach, which involves combining an antibody with radiation, has since been further developed and is expected to enter early-stage human clinical studies in 2007.

"This is an excellent example of how scientific research in one discipline may have payoffs in a completely unpredictable way," says NIAID Director Anthony S. Fauci, M.D. "This important AIDS-related research has led to the development of a promising therapeutic strategy for a terrible cancer that affects thousands of people each year".

Arturo Casadevall, M.D., Ph.D., of the Albert Einstein College of Medicine at Yeshiva University, in New York City, and his research team began studying the biology of the skin pigment melanin to better understand why its synthesis plays a role in the process whereby certain yeast-like fungi, specifically Cryptococcus neoformans, cause disease in some people. C. neoformans can cause cryptococcosis, a potentially fatal fungal infection that can lead to inflammation of the brain and death in people with AIDS and other immunocompromised individuals.........

Posted by: Sean      Permalink         Source

December 6, 2006, 8:29 PM CT

Galaxies And Darwinian Evolution

Using VIMOS on ESO's Very Large Telescope, a team of French and Italian astronomers have shown the strong influence the environment exerts on the way galaxies form and evolve. The scientists have for the first time charted remote parts of the Universe, showing that the distribution of galaxies has considerably evolved with time, depending on the galaxies' immediate surroundings. This surprising discovery poses new challenges for theories of the formation and evolution of galaxies.

The 'nature versus nurture' debate is a hot topic in human psychology. But astronomers too face similar conundrums, in particular when trying to solve a problem that goes to the very heart of cosmological theories: are the galaxies we see today simply the product of the primordial conditions in which they formed, or did experiences in the past change the path of their evolution?

In a large, three-year long survey carried out with VIMOS [1], the Visible Imager and Multi-Object Spectrograph on ESO's VLT, astronomers studied more than 6,500 galaxies over a wide range of distances to investigate how their properties vary over different timescales, in different environments and for varying galaxy luminosities [2]. They were able to build an atlas of the Universe in three dimensions, going back more than 9 billion years.........

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December 5, 2006, 8:56 PM CT

Southern Ocean Could Slow Global Warming

The Southern Ocean may slow the rate of global warming by absorbing significantly more heat and carbon dioxide than previously thought, as per new research.

The Southern Hemisphere westerly winds have moved southward in the last 30 years. A new climate model predicts that as the winds shift south, they can do a better job of transferring heat and carbon dioxide from the surface waters surrounding Antarctica into the deeper, colder waters.

The new finding surprised the scientists, said lead researcher Joellen L. Russell. "We think it will slow global warming. It won't reverse or stop it, but it will slow the rate of increase."

The new model Russell and her colleagues developed provides a realistic simulation of the Southern Hemisphere westerlies and Southern Ocean circulation.

Prior climate models did not have the winds properly located. In simulations of present-day climate, those models distorted the ocean's response to future increases in greenhouse gases.

"Because these winds have moved poleward, the Southern Ocean around Antarctica is likely to take up 20 percent more carbon dioxide than in a model where the winds are poorly located," said Russell, an assistant professor of geosciences at The University of Arizona in Tucson.........

Posted by: Tyler      Permalink         Source

December 5, 2006, 8:37 PM CT

Measuring Carbon Without Destroying Trees

USDA Forest Service (FS) scientists have provided the first proof of concept for a method that allows researchers to study below-ground carbon allocation in trees without destroying them. In the latest issue of the journal Plant, Cell and Environment, Kurt Johnsen and fellow scientists at the FS Southern Research Station unit in Research Triangle Park, NC, describe a reversible, non-destructive chilling method that stops the movement of carbon into root systems.

The photosynthetic process of plants has been estimated to account for almost half of the carbon circulating in the Earth's systems. Reliable data has been developed on carbon cycling in the above-ground processes of trees, but how much carbon is actually moved and stored below the ground has not yet been determined. Most methods to study below-ground processes involve destroying the roots as well as the mycorrhizal communities that live symbiotically with root systems.

"Below-ground carbon allocation is one of the least understood processes in tree physiology," says Johnsen. "Being able to accurately measure it is essential for modeling forest and ecosystem productivity and carbon sequestration, but most methods disturb the root-mycorrhizal continuum that plays an essential role in nutrient transport".........

Posted by: Tyler      Permalink         Source