                  |
 Net World Directory Your personal directory for the internet | ||
| Net World Directory: Archives of science blog |
 | ||
Archives Of Science Blog From NetworlddirectorySubscribe To Science Blog RSS Feed 
Red Tide CausesTurtle Death
The culprit is microscopic in size, but its effects are monstrous. Deadly algal blooms- known as "red tide" for the reddish pigments contained in these single-celled organisms at the base of the ocean's food web-have caused the deaths of some 200 sea turtles. The event occurred in November 2005 off the southern coast of El Salvador. Soon after the first appearance of the red-tinged water, some of the region's people fell ill. The government responded by closing shellfish beds in the area, warning against eating seafood from affected areas. The first reports of dead and dying sea turtles washing up on shore occurred in the second week of December. Most of the victims were olive ridley turtles, and a few green and hawksbill turtles were among those stranded. Working quickly, the Salvadoran government and the US Agency for International Development (USAID) called for assistance. WCS veterinary pathologist Dr. Julie White traveled to the site of the crisis in January, where she performed post-mortem examinations on one of the turtles. While there, she also trained Salvadorian colleagues in tissue collection techniques. Samples were then sent to Florida's Fish and Wildlife Research Institute, operated by the National Marine Fisheries Service and the University of Florida. There, researchers diagnosed the problem: high densities of saxitoxin, which is produced by species of algae and sea plankton. The toxin affects the nervous systems of humans and animals alike......... Posted by: Ashley Permalink Source Caribbean And Central America May Have Less Summer Rain
Their research is based on an analysis of 10 global climate computer simulations, from the U.S. National Center for Atmospheric Research, the U.S. National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory, and from Australia, Britain, France, Gera number of and Japan. (The study is published this week in the PNAS online edition.) The majority of the computer models calls for a substantial decrease in tropical rainfall to occur by 2054, or sooner under some of the models, said J. David Neelin, UCLA professor of atmospheric and oceanic sciences, a member of UCLA's Institute of Geophysics and Planetary Physics, and lead author of the study. By the end of this century, the models call for a decrease in summer rainfall of 20 percent or more in parts of the Caribbean and Central America, Neelin said. The winter change in rainfall in this region is not dramatic, added Neelin, who noted that summer and winter rains occur by very different climate phenomena. If the models prove correct, the decreased rainfall would be a consequence of human-induced global warming, he said......... Posted by: Tyler Permalink Source Graphite-based Circuitry May Be Foundation For New Devices
In a paper published April 13 in Science Express, an online advance publication of the journal Science, researchers at the Georgia Institute of Technology and the Centre National de la Recherche Scientifique (CNRS) in France report measuring electron transport properties in graphene that are comparable those seen in carbon nanotubes. Unlike carbon nanotubes, however, graphene circuitry can be produced using established microelectronics techniques, allowing researchers to envision a "road map" for future high-volume production. "We have shown that we can make the graphene material, that we can pattern it, and that its transport properties are very good," said Walt de Heer, a professor in Georgia Tech's School of Physics. "The material has high electron mobility, which means electrons can move through it without much scattering or resistance. It is also coherent, which means electrons move through the graphene much like light travels through waveguides". The results should encourage further development of graphene-based electronics, though de Heer cautions that practical devices may be a decade away......... Posted by: Sarah Permalink Source Testing Fluid Compatibility
A new NIST microfluidic instrument measures the mixing compatibility of complex liquids by observing how drops of one fluid flowing within a "river" of a second fluid change in shape as they travel through channels of various sizes. Credit: Credit line: S.Hudson/NIST
To help industrial engineers improve their ability to systematically test new product formulations, scientists at the National Institute of Standards and Technology (NIST) have developed a microfluidic instrument that quickly measures interfacial tension. The instrument is relatively simple and includes a series of channels ranging from 700 micrometers to 50 micrometers wide. Fluids are pumped toward a "T" intersection where drops of one liquid are pinched off and flow along a "river" of the second liquid. As the spherical drops flow through constriction points in the channel, they speed up and elongate. The degree to which the drops stretch out depends on the interfacial tension between the two fluids. High levels of tension exert more pressure on the drops, keeping them more nearly spherical. Just as the mood of a party goes through stages, the tension between newly mixed liquids can change over time, and the device tracks these changes as the drops move downstream through the channel. A camera captures 100 pictures per second to record the changes, and an algorithm analyzes the data and produces a measurement in approximately 1 second......... Posted by: Sarah Permalink Source Temperatures Causes Niagara Falls' Mist
The suspicion was that new high-rise buildings were altering airflow patterns, contributing to a higher, thicker mist plume. Consultants conducted wind tunnel experiments that seemed to confirm that mist levels were enhanced by the tall buildings around the falls, a report that circulated in the Canadian news media. Now University at Buffalo geologists have determined that the high-rise hotels are probably not to blame. "As per our findings, it is unlikely that the buildings at the falls enhance the mist," said Marcus Bursik, Ph.D., professor in the Department of Geology in the UB College of Arts and Sciences, who led the study with several students who were investigating the plume for their graduate-degree projects. "Rather, our data show that it's air and water temperature that control the amount of mist. "It turns out that the bigger the temperature difference between the air and the water, the higher and more substantial is the mist plume and the thicker is the mist at the Falls," he continued......... Posted by: Tyler Permalink Source New student-designed system tracks firefighters, special forces
A group of University of Florida engineering students has designed a system to locate, track and communicate with special forces troops or firefighters in remote areas where no cell towers or other communications infrastructure exist. The system allows soldiers or firefighters to pinpoint their own and their comrades' whereabouts on digital maps displayed on handheld personal digital assistants. It can transmit this information via satellite phone, making it available to Internet-connected commanders or observers anywhere in the world. It even gives users the option of punching a panic button or sending text messages such as "need more water," "pull me out," or simply "help!". "It's live and it's in real time," said UF electrical and computer engineering senior Rolando Estrella. Estrella is among seven UF engineering seniors who spent the semester creating the system as part of the College of Engineering's Integrated Product & Process Design program. The 11-year-old program's goal is to assist corporations, small businesses and government agencies with engineering problems while giving engineering students practical experience working on real-world projects......... Posted by: Kevin Permalink Source Interstellar Chemical Tamed in The Lab
Interstellar molecules in a bottle at UCR
The finding of their paper, titled Cyclopropenylidenes: From Interstellar Space to an Isolated Derivative in the Laboratory are being released recently in Science Express a precursor to its publication in the journal Science. The co-authors are Vincent Lavallo, Yves Canac and Bruno Donnadieu who work in the laboratory of Distinguished Professor of Chemistry Guy Bertrand at UCR; and Chemistry Professor Wolfgang W. Schoeller of Gera number of's Universität Bielefeld. "This is about a compound that is very abundant in deep space, which was supposed to not be able to exist in the laboratory, and we found a way to slightly modify it and make it stable," said Bertrand. The new molecule belongs to a family of compounds known as carbenes, very few of which are stable. However, carbenes are now widely used to prepare catalysts that have a number of applications in industries such as pharmaceuticals, plastics and other petrochemicals. The cyclopropenylidene that exists naturally in space is made of three carbon atoms arranged in a triangle with two hydrogen atoms attached. The UCR scientists synthesized a more stable version by replacing the hydrogen with two nitrogen atoms. Because of its unique shape and size, the new carbene prepared at UCR might lead to even more powerful catalysts......... Posted by: Sarah Permalink Source Higher Carbon Dioxide, Lack Of Nitrogen Limit Plant Growth
That, in turn, is likely to dampen the ability of plants to offset increases in atmospheric carbon dioxide. "We found that atmospheric carbon dioxide levels may rise even faster than anticipated, because ecosystems likely will not store as much carbon as had been predicted," said Peter Reich of the University of Minnesota, lead author of the study, which was conducted at the National Science Foundation (NSF)'s Cedar Creek Long-Term Ecological Research (LTER) site in Minn. "As a result, soils will be unable to sustain plant growth over time [as atmospheric carbon dioxide continues to increase]," said plant ecologist David Ellsworth of the University of Michigan. Estimating the role of terrestrial ecosystems as current and future sinks--or storage places--for excess carbon dioxide hinges on an ability to understand the complex interaction between atmospheric carbon dioxide and nitrogen in soils, the scientists believe......... Posted by: Jessica Permalink Source Evolutionary Consequences Of Bluebird Aggression
This study, conducted by Renee Duckworth, Ph.D., suggests the birds may play more active roles in their own natural selection than traditional models of evolution would support. "The traditional view of evolution is that organisms are passive creatures on which natural selection operates," said Duckworth, who just completed her doctoral training at Duke. But her research results, published online on Wednesday, April 12, 2006, in the journal Proceedings of the Royal Society B, suggest a different model, at least among these bluebirds. "By selecting the environment in which they live, animals can actively affect the natural selection they experience," Duckworth said in an interview. "The main message of this study is that the ability of organisms to choose their environment needs to be made a more explicit part of evolutionary theory". In her studies, funded by the National Science Foundation, Duckworth followed up on previous findings that adult western bluebirds aggressively defend large breeding territories and also use different foraging strategies in wooded and open habitats......... Posted by: Ashley Permalink Source Frictionless Motion In Water
Each rotating cyanide ion creates a shock wave that throws back the surrounding water molecules, allowing it to spin for a time with essentially no friction.
Credit: Nicolle Rager-Fuller, National Science Foundation
Indeed, the technique gives chemists a potential new tool to influence how a reaction progresses, as one way to do that is to isolate an interacting molecule from its surroundings. In experiments they describe in a recent issue of the journal Science, the chemists start with a water sample containing cyanide ions, each of which is basically a molecular stick with a carbon atom at one end and a nitrogen atom at the other. Then they spin the sticks to with a laser. Within the first quarter-turn, each rotating cyanide ion creates a shock wave that throws back the surrounding water molecules. (Bradforth, who is part of the study team, likens the phenomenon to a passenger swinging a suitcase in a crowded airport terminal, minus the real-life bruises and hurt feelings.) Inside the resulting bubble, the molecule will then continue whirling for a time with essentially no friction......... Posted by: Sarah Permalink Source |
||
| Net World Directory: Navigation |