May 12, 2008, 9:32 PM CT

Human vision inadequate for research on bird vision

The most attractive male birds attract more females and as a result are most successful in terms of reproduction. This is the starting point of a number of studies looking for factors that influence sexual selection in birds. However, is it reasonable to assume that birds see what we see? As per a research findings reported in the latest issue of American Naturalist, Uppsala scientists show that our human vision is not an adequate instrument.

The results mean that a number of studies on sexual selection may need to be re-reviewed, says Anders Odeen, research assistant at the Department of Animal Ecology at Uppsala University, who carried out this study with his colleague Olle Hstad.

The significance of birds plumage, both in terms of richness of colour and particular signals, has been shown to be a major factor in birds choice of partner. In order to assess the colours of birds, everything from binoculars to RGB image analyses are used. However, most studies are based on the hypothesis that human colour vision can be used to assess what birds see.

Its a bit like a colour blind person describing the colours of clothes its often quite accurate but sometimes it can go badly wrong.

This problem has been discussed in the research arena, but so far no study has been able to show its extent. The Uppsala scientists used a mathematical model to investigate how bird and human retina work. Using the model combined with information on differences in the colour-sensitive cones of the eye, they have been able to figure out how colour contrasts are perceived. Greater colour contrast can be translated as richness of colour or more brightly coloured......... Posted by: Kelly      Read more         Source

May 12, 2008, 8:23 PM CT

First Veterinary Corneal Implant Procedure In U.s.

Sinisa Grozdanic an assistant professor of Veterinary Clinical Sciences performed the surgery that restored sight to 7-year-old Dixie, a Mountain Cur breed owned by Brett Williams of Runnells.

"We are excited for Dixie," said Grozdanic. "She was our patient for such a long time and nothing really worked. She was gradually going down visually and we were finally able to do something to definitely improve her quality of life".

"She is my pet and my friend," said Williams. "She is the best dog I've ever had. Even when she was almost blind, she was still my best dog".

Dixie, who had gained weight due to inactivity from her blindness, has lost seven pounds since the surgery.

"She used to walk right behind me when we'd go for a walk. She couldn't see and was scared," said Williams. "Now she wants to run ahead".

Dixie's sight was restored through a two-step surgical procedure that involves cutting into the eye to take out the cloudy cornea and inserting a permanent, plastic cornea. The new cornea is sutured, or stitched, into place. The entire eye including the new, plastic cornea is then covered with tissue from the dog to help the eye heal from the surgery. Because of the tissue and the bandages, the dog cannot see after this procedure......... Posted by: Kelly      Read more         Source

May 12, 2008, 8:08 PM CT

Warming a greater danger to tropical species

Polar bears fighting for survival in the face of a rapid decline of polar ice have made the Arctic a poster child for the negative effects of climate change. But new research shows that species living in the tropics likely face the greatest peril in a warmer world.

A team led by University of Washington researchers has observed that while temperature changes will be much more extreme at high latitudes, tropical species have a far greater risk of extinction with warming of just a degree or two. That is because they are used to living within a much smaller temperature range to begin with, and once temperatures get beyond that range a number of species might not be able to cope.

"There's a strong relationship between your physiology and the climate you live in," said Joshua Tewksbury, a UW assistant professor of biology. "In the tropics a number of species appear to be living at or near their thermal optimum, a temperature that lets them thrive. But once temperature gets above the thermal optimum, fitness levels most likely decline quickly and there may not be much they can do about it."

Arctic species, by contrast, might experience temperatures ranging from subzero to a comparatively balmy 60 degrees Fahrenheit. They typically live at temperatures well below their thermal limit, and most will continue to do so even with climate change......... Posted by: Kelly      Read more         Source

May 7, 2008, 6:26 PM CT

Platypus Genome Decoded

The curious discovery of the duck-billed, egg-laying, otter-footed, beaver-tailed, venomous platypus in Australia in 1798 convinced British researchers that it must be a hoax. Sketches of its appearance were believed to be impossible.

But new research proves that the oddness of the platypus' looks isn't just skin-deep. Platypus DNA is an equally cobbled-together array of avian, reptilian and mammalian lineages that may hold clues for human disease prevention.

Mark Batzer and Andrew C. Pereboom of Louisiana State University, along with an international group of researchers led by Wes Warren at Washington University in St. Louis, Missouri, recently completed the first draft sequence and analysis of the platypus genome.

It was the first genome sequencing project of a mammal that lays eggs, confirming that platypus DNA also looks like something of a patchwork.

"Their genomic organization was strange and a little unexpected," says Batzer. "It appeared much more bird- and reptile-like than mammalian, even though it is indeed classified as a mammal.".

Having the genome in hand is a huge step for researchers seeking new details about evolution and human disease. The fact that the platypus is an ancient animal that is relatively primitive and unchanged may be a scientific boon for researchers......... Posted by: Kelly      Read more         Source

May 5, 2008, 5:46 PM CT

Global warming will negatively impact tropical species

Global warming is likely to reduce the health of tropical species, researchers from UCLA and the University of Washington report May 6 in Proceedings of the National Academy of Sciences.

At the same time, a little bit of warming may actually move certain organisms, especially insects, in the high latitudes closer to their optimal temperature, the scientists say.

"In the tropics, most of the organisms we have studied, from insects to amphibians and reptiles, are already living at their optimal physiological temperatures," said Curtis Deutsch, UCLA assistant professor of atmospheric and oceanic sciences and co-author of the study. "When warming starts, they do less well as they move toward the hottest end of their comfort range. Even a modest increase in temperature appears rather large to them and negatively impacts their population growth rates." .

Why should we be concerned with the fate of insects in the tropics? .

"The biodiversity of the planet is concentrated in tropical climates, where there is a tremendous variety of species," Deutsch said. "This makes our finding that the impacts of global warming are going to be most detrimental to species in tropical climates all the more disturbing. In addition, what hurts the insects hurts the ecosystem. Insects carry out essential functions for humans and ecosystems such as pollinating our crops and breaking down organic matter back into its nutrients so other organisms can use them. Insects are essential to the ecosystem." ......... Posted by: Kelly      Read more         Source

May 2, 2008, 8:14 AM CT

Bees Disease - One Step Closer To Finding A Cure

Researchers in Gera number of have discovered a new mechanism of infection for the most fatal bee disease. American Foulbrood (AFB) is the only infectious disease which can kill entire colonies of bees. Every year, this notifiable disease is causing considerable economic loss to beekeepers all over the world. The only control measure is to destroy the infected hive.

The mechanism of infection (pathogenic mechanism) was originally believed to be through the growth of a bacterium called Paenibacillus larvae in the organ cavity of honey bee larvae. The accepted view was that the bacteria germinate preferentially at either end of the gut of honey bee larvae then make holes in the gut wall and enter the larval organ cavity, the presumed primary place of bacterial proliferation.

In a paper published in Environmental Microbiology, Professor Elke Genersch and his colleagues in Berlin explain that they have discovered that these bacteria cause infection in a completely different way. They colonize the larval midgut, do most of their multiplying in the mid-gut - living from the food ingested by the larvae - until eventually the honey bee larvae gut contains nothing but these disease-causing (pathogenic) bacteria. It isn't until then that the bacteria 'burst' out of the gut into the organ cavity thereby killing the larvae. These findings are a major breakthrough in honeybee pathology......... Posted by: Kelly      Read more         Source

April 30, 2008, 6:58 PM CT

It's a unisex brain with specific signals

Research by Yale researchers shows that males and females have essentially unisex brains at least in flies as per a recent report in Cell designed to identify factors that are responsible for sex differences in behavior.

The scientists showed that a courting song and dance routine that only male flies naturally perform one wing is lifted and wiggled to make a humming song can also be triggered in female flies by artificially stimulating particular brain cells that are present in both sexes. It isnt what youve got its how you use it, the authors say.

It appears there is a largely bisexual or unisex brain. Anatomically, the differences are subtle and a few critical switches make the difference between male and female behavior, said senior author Gero Miesenboeck, formerly of Yale University and now at the University of Oxford.

As per the authors, most male animals have to perform elaborate courtship displays to try to convince the female that they are worthy mates. Their study was designed to see what neurons were responsible for behavior in the courtship dance of flies, and how the neural circuits in males and females differed. To do this, they genetically engineered specific neurons in the fly to respond to light. This optical trick allowed them to activate the neural circuits that control the behavior pattern directly......... Posted by: Kelly      Read more         Source

April 30, 2008, 6:36 PM CT

Sequencing of Protein from T. rex Confirms Dinosaurs' Link to Birds

Researchers have put more meat on the theory that dinosaurs' closest living relatives are modern-day birds.

Molecular analysis, or genetic sequencing, of a 68-million-year-old Tyrannosaurus rex protein from the dinosaur's femur confirms that T. rex shares a common ancestry with chickens, ostriches, and to a lesser extent, alligators.

The dinosaur protein was wrested from a fossil T. rex femur discovered in 2003 by paleontologist John Horner of the Museum of the Rockies; the bone was found in a fossil-rich stretch of land in Wyoming and Montana.

The new research results, published this week in the journal Science, represent the first use of molecular data to place a non-avian dinosaur in a phylogenetic tree, a "tree of life," that traces the evolution of species.

"These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur," says Science paper co-author Chris Organ, a researcher at Harvard University. "Even though we only had six peptides--just 89 amino acids--from T. rex, we were able to establish these relationships.".

"Tests of the peptide sequences in T. rex bone fossils have confirmed that newer methods of molecular systematics agree with more traditional methods of taxonomic classification based on morphology, or shapes," says Paul Filmer, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research......... Posted by: Kelly      Read more         Source

April 30, 2008, 5:52 PM CT

Photochemical Compass for Bird Navigation

A team of scientists at Arizona State University and the University of Oxford are the first to model a photochemical compass that may simulate how migrating birds use light and Earth's weak magnetic field to navigate. The team reports in the April 30, 2008, online issue of Nature that the photochemical model becomes sensitive to the magnitude and direction of weak magnetic fields similar to Earth's when exposed to light. The research funded by the National Science Foundation (NSF) demonstrates that this phenomenon, known as chemical magnetoreception, is feasible and gives insight into the structural and dynamic design features of a photochemical compass.

The most common bird migration pattern in the northern hemisphere is to fly north in the summer to breed in the Artic and to fly south to warmer regions for the winter.

Regardless of which way they are flying, migrating birds are important ecologically as a food source for other animals. They also transport plankton, materials involved in plant reproduction and hitchhikers such as ticks and lice, which can carry micro-organisms harmful to human health.

About 50 animal species, ranging from birds and mammals to reptiles and insects, use Earth's weak magnetic field for navigation. Earth's magnetic field ranges from approximately 30 to 60 millionths of one tesla. By comparison, magnetic resonance imaging, or MRI, uses magnetic fields from 1.5 to 3.0 tesla......... Posted by: Kelly      Read more         Source

April 30, 2008, 5:38 PM CT

Engineering and invention on the half-shell

Marine snails, sea urchins, and other animals from the sea are teaching scientists in UC Riversides Department of Chemical and Environmental Engineering how to make the world a better place.

Consider, for example, the possibilities of designing a lightweight armor that would protect U.S. soldiers in Iraq from Improvised Explosive Devices. Or, what flexible ceramics might offer industry. Or, how everyone could benefit from new ways of producing and storing energy.

Nature holds these secrets and the answers to the questions that Prof. David Kisailuss research group is learning how to ask. My hope, Kisailus said, is that we can truly learn from these organisms how to design, optimize, and synthesize engineering materials that display properties that we as engineers can only dream of.

Studying ocean animals daily as they grow seems a tough task for Inland Southern California scientists. Instead of commuting to the coast, the scientists have brought the oceans to UCR in a unique 500-gallon seawater system that dominates the Biomimetic and Nanostructured Materials Laboratory, offering homes for both coldwater (60 degrees Fahrenheit) and tropical (80 degrees Fahrenheit) species.

While some people trek to exotic, faraway locales to admire the beauty of coral reefs, at UCR, people simply can visit Bourns Hall to see a dramatic and authentic tropical coral reef ecosystem. Another showcase tank boasts a thriving coldwater marine population that includes Californias red abalone (Haliotis rufescens), purple and brown sea urchins (Strongylocentrotus purpuratus and Lytechinus pictus), giant keyhole limpets (Megathura crenulata), several coral species (Balanophyllia elegans, Astrangia lajollaensis and Paracyathus stearnsi), along with numerous colonies of club-tipped corallimorpharians (Corynactis californica)......... Posted by: Kelly      Read more         Source