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November 1, 2006, 5:26 PM CT

Why There Are More Species In The Tropics?

Why There Are More Species In The Tropics?
Why are there more species in the tropics than in the temperate regions of the globe? A number of of the world's species live in the tropics (perhaps more than half), but the reason has been debated for more than 100 years.

A number of scientists have hypothesized that climatic factors somehow cause species to originate more quickly in tropical regions. In a paper appearing in the recent issue of The American Naturalist, John Wiens and a group of scientists from Stony Brook University have shown that, contrary to expectations, species seem to evolve at similar rates in tropical and temperate regions. What causes the difference in species numbers between tropical and temperate regions is not something special about the tropics that leads to more rapid speciation, but rather that the temperate areas were colonized more recently, leaving less time for species to originate and accumulate in these regions.

The scientists studied the causes of high tropical species richness in treefrogs in the Americas. Combining analyses of evolutionary trees based on DNA sequences with GIS-based methods for analyzing the effects of climate on species distributions, the scientists found no relationship between how quickly species originate within a group and whether that group is tropical or temperate.........

Posted by: Nora      Permalink         Source


November 1, 2006, 4:13 PM CT

Floating Lovers Count Too

Floating Lovers Count Too Researchers from Spain looked at population data for the Spanish imperial eagle (Aquila adalberti) over the last century
In a paper from the recent issue of The American Naturalist, Vincenzo Penteriani, Fermin Otalora, and Miguel Ferrer, scientists 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 observed 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".........

Posted by: Nora      Permalink         Source


October 31, 2006, 9:25 PM CT

Save Threatened Turtles

Save Threatened Turtles Cayman Islands loggerhead turtle
Credit: Janice Blumentha
Ecology and conservation experts from the University of Exeter today urge international governments to work together to protect threatened Caribbean sea turtle populations.

The Cayman Islands, a UK Overseas Territory, once supported one of the world's largest sea turtle rookeries, which comprised some 6.5 million adult green and loggerhead turtles. These populations were driven into decline from the mid-1600s onwards, when massive harvesting of nesting turtles began. Only a few dozen individuals survive today.

New research, led by the University of Exeter's School of Biosciences and the Cayman Islands Department of Environment, reveals the astonishing distances these animals travel and the extent to which they are now threatened. The study was published open access today in the international conservation journal Endangered Species Research.

Marine turtles spend most of their lives at sea, but where these Cayman Islands survivors live when they are not nesting has been a mystery until now. Experts from the University of Exeter, the Cayman Islands Department of Environment and Duke University, USA, followed the journeys of ten endangered adult females over three years.

Using satellite transmitters, the team tracked the turtles travelling as far as Belize, Guatemala, Honduras, Mexico, Nicaragua and the USA. On these long journeys, turtles face the risk of being caught for meat, as well as accidentally captured by shrimp trawls, longlines, and gillnets. As turtles travel across boundaries between countries, conservation legislation is inconsistently applied and enforced, leaving them vulnerable.........

Posted by: Nora      Permalink         Source


October 31, 2006, 6:58 PM CT

Snake on a Galactic Plane!

Snake on a Galactic Plane!
Something scary appears to be slithering across the plane of our Milky Way galaxy in this new Halloween image from NASA's Spitzer Space Telescope. The snake-like object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say its "belly" may be harboring beastly stars in the process of forming.

"The snake is an ideal place to hunt for massive forming stars as they have not had time to heat up and destroy the cloud they are born in," said Dr. Sean Carey, also known as "Dr. Scarey," of NASA's Spitzer Science Center. Dr. Scarey, who is leading the new research, was also principal investigator of a previous Halloween image from Spitzer, showing a 'great galactic ghoul'.

Spitzer was able to spot the sinuous cloud using its heat-seeking infrared vision. The object is hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because its heat, or infrared light, can sneak through the dust, it first showed up in infrared images from past missions. The cloud is so thick with dust that if you were to somehow transport yourself into the middle of it, you would see nothing but black, not even a star in the sky. Now, that's spooky!

Spitzer's new view of the snake provides the best look at what lurks inside. The yellow and orange spots located on and around it are massive stars just beginning to take shape. The bright red spot located on its belly is a monstrous stellar embryo, with about 20 to 50 times the mass of our sun.........

Posted by: Edwin      Permalink         Source


October 31, 2006, 6:49 PM CT

Esperanza Fire

Esperanza Fire
Smoke from the Esperanza Fire washed over the mountains southeast of Los Angeles and over the Pacific Ocean.
Waves of gray-brown smoke washed over the mountains southeast of Los Angeles and out over the Pacific on Oct. 26, 2006, on the same day on which four firefighters were killed fighting the blaze. West of Palm Springs, Calif., the Esperanza Fire had ballooned under the influence of Santa Ana winds to encompass more than 19,000 acres as of the morning of Oct. 27, according to the daily report from the National Interagency Fire Center. Racing through grass, brush, and timber, the blaze had forced hundreds to evacuate, and it killed several firefighters who were working to protect homes. Fire officials are reporting the cause of the blaze as arson.

This photo-like image shows the fire and surrounding area captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on Oct. 26. Places where MODIS detected actively burning fire are outlined in red. The Santa Ana Mountains peak out from beneath the smoke near the southeastern suburbs of Los Angeles.

Santa Ana winds are a California firefighter's nightmare. These blustery, dry and often hot winds blow out of the desert and race through canyons and passes in the mountains on their way toward the coast. The air is hot not because it is bringing heat from the desert, but because it is flowing downslope from higher elevations. As fall progresses, cold air begins to sink into the Great Basin deserts to the east of California. As the air piles up at the surface, high pressure builds, and the air begins to flow downslope toward the coast. When winds blow downslope, the air gets compressed, which causes it to warm and dry out. In fact, the air can warm at a rate of 10 degrees Celsius per kilometer of descent (29 degrees Fahrenheit per mile). Canyons and passes funnel the winds, which increases their speed. Not only do the winds spread the fire, but they also dry out vegetation, making it even more flammable.........

Posted by: Edwin      Permalink         Source


October 31, 2006, 6:39 PM CT

Halloween For Nebula

Halloween For Nebula Credit: Adam Block, NOAO, AURA, NSF
The dark nebula SH2-136 appears to be celebrating Halloween all of the time. The complex process of star formation create dust clouds of many shapes and sizes -- it is human perception that might identify a ghoulish creature, on the right of the above image, chasing humans.

Halloween's modern celebration retains historic roots in dressing to scare away the spirits of the dead. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere). With our modern calendar, however, the real cross-quarter day will occur next week. Other cross-quarter markers include Groundhog Day and Walpurgis Night.........

Posted by: Edwin      Permalink         Source


October 31, 2006, 5:06 AM CT

New Species Discovered Inhawaiian Islands

New Species Discovered Inhawaiian Islands This crab was collected during a three-week expedition to the Northwestern Hawaiian Island National Monument
Credit: Joel Martin, NHMLAC, NOA
A three-week scientific expedition to French Frigate Shoals in the Northwestern Hawaiian Islands Marine National Monument returned to Honolulu on Sunday with the discovery of many new species and a better understanding of marine biodiversity in the Hawaiian Archipelago.

An all-star team of world-renowned taxonomists (biologists specializing in identifying and naming organisms) and an experienced support crew collected and photographed many species that they cannot identify and are thought to be new species to science. The expedition found several potentially new species of crabs, corals, sea cucumbers, sea quirts, worms, sea stars, snails, and clams. Many other species were found that are known from other areas but have never been recorded from French Frigate Shoals, the Northwestern Hawaiian Islands, or even the Hawaiian Archipelago. From this expedition, well over a hundred new species records will likely be identified for French Frigate Shoals.

Scientists aboard the National Oceanic and Atmospheric Administration Ship Oscar Elton Sette conducted biodiversity surveys at French Frigate Shoals, with a focus on the small marine organisms - crabs, worms, and many other invertebrates, algae, and even microbes - which are often overlooked but that make up the majority of living diversity on coral reefs. "It was a very successful expedition by almost any criterion, and the discovery phase has really only just begun. In the coming months, and even over the next several years, we will be conducting morphological examinations and analyzing genetic sequence data in order to further identify and classify these organisms, and possibly to shed some light on where these species originated," said Dr. Joel W. Martin of the Natural History Museum of Los Angeles County. "What we did not find is also important. There were several groups of animals that we expected to find but did not find, or found only rarely, such as porcellanid crabs. The apparent absence of these common reef organisms may provide insight into how the unique flora and fauna of French Frigate Shoals came to be".........

Posted by: Nora      Permalink         Source


October 31, 2006, 4:52 AM CT

Global Warming And Insect Population Growth

Global Warming And Insect Population Growth
Insects have proven to be highly adaptable organisms, able through evolution to cope with a variety of environmental changes, including relatively recent changes in the world's climate. But like something out of a scary Halloween tale, new University of Washington research suggests insects' ability to adapt to warmer temperatures carries an unexpected consequence - more insects.

It appears that insect species that adapt to warmer climates also will increase their maximum rates of population growth, which UW researchers say is likely to have widespread affects on agriculture, public health and conservation.

Many studies have shown that insects readily adapt to the temperature of their environment. For example, those living in deserts easily tolerate high temperatures but are much less tolerant of cold temperatures than insects living in mountains. Now UW biology researchers have found that insect species that have adapted to warmer environments also have faster population growth rates. The research shows, in effect, that "warmer is better" for insects, said Melanie Frazier, a UW biology doctoral student.

"Enhanced population growth rates for butterflies might be a good thing, but enhanced growth rates for mosquito populations is much more dubious," said Frazier, who is lead author of the new research, published in the October edition of the journal The American Naturalist.........

Posted by: Nora      Permalink         Source


October 31, 2006, 4:26 AM CT

Technique Harnesses 3-D Game Engines

Technique Harnesses 3-D Game Engines Production still of a robot avatar from machinima research at MIT.
Image courtesy / Beth Coleman, CMS
Student researchers working with Beth Coleman, assistant professor in comparative media studies and in the Program in Writing and Humanistic Studies, are exploring machinima, one branch of the rapidly evolving world of computer animation. As members of the Machinima Work Group, they are experimenting in the medium to find new modes of cinematic expression.

Machinima (pronounced "machine-ima," the word is coined from "machine" and "cinema") is animation that is made by harnessing 3-D game engines, such as those used in Xbox or PlayStation games, and adding original content--dialogue, dramatic situations, and new or modified characters. Relative to traditional computer-generated imagery (CGI), in which animators must create the characters, scenes (levels) and action from scratch, machinima is fast and cheap--though still enormously time-consuming. The most well-known work of machinima to date is "Red vs. Blue," a comic sci-fi series based on the popular Xbox games Halo and Marathon. But many, including Coleman's group, are working to expand the medium above and beyond the genre of parody and to gauge its potential for artistic and cinematic expression.

Coleman explained in a recent interview that the medium has really exploded in the past five years, to the point where you now see ads on television that are made in machinima.........

Posted by: John      Permalink         Source


October 31, 2006, 4:09 AM CT

Microwave Your French Fries Before You Fry Them

Microwave Your French Fries Before You Fry Them
Microwaving your French fries before you fry them reduces the levels of a cancer-causing substance, reveals findings published recently in the SCI's Journal of the Science of Food and Agriculture.

The discovery of acrylamide - a possible carcinogenic in humans - has led to much research being done to investigate the benefits of alternative cooking methods. Acrylamide forms during processes such as frying, baking and roasting where high-temperature and low-moisture conditions exist.

Eventhough numerous studies have been conducted to explore the possibilities of reducing acrylamide levels in French fries, a team of scientists from Turkey has shown that by reducing the frying time and hence the acrylamide formation by microwave pre-cooking of potato strips previous to frying.

Publishing their work in the Journal of the Science of Food and Agriculture, the researches showed that microwave application previous to frying resulted in a marked reduction of the acrylamide level in the surface region. When the potato strips were subjected to frying after a microwave pre-cooking step, acrylamide content in the whole potato strip was reduced by 36%, 41% and 60% for frying at 150, 170 and 190oC respectively.

"Microwaving French fries before cooking takes little time and in fact, microwave pre-cooked samples fried to the same degree of cooking appeared to have a more acceptable colour, probably due to the more gentle heat therapy they experienced during frying," says lead author Koray Palazoglu, of the University of Mersin, Turkey.........

Posted by: Nora      Permalink         Source


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