Images of living human retinas showing the wide diversity of number of cones sensitive to different colors, Eurekalert reported.
First-ever images of living human retinas have yielded a surprise about how we perceive our world. Researchers at the University of Rochester have found that the number of color-sensitive cones in the human retina differs dramatically among people--by up to 40 times--yet people appear to perceive colors the same way. The findings strongly suggest that our perception of color is controlled much more by our brains than by our eyes.
“We were able to precisely image and count the color-receptive cones in a living human eye for the first time, and we were astonished at the results,“ says David Williams, Allyn Professor of Medical Optics and director of the Center for Visual Science.
The technology, known as adaptive optics, was originally used by astronomers in telescopes to compensate for the blurring of starlight caused by the atmosphere.
Williams turned the technique from the heavens back toward the eye to compensate for common aberrations. The technique allows researchers to study the living retina in ways that were never before possible.
The pigment that allows each cone in the human eye to react to different colors is very fragile and normal microscope light bleaches it away. This means that looking at the retina from a cadaver yields almost no information on the arrangement of their cones, and there is certainly no ability to test for color perception.
Likewise, the amino acids that make up two of the three different-colored cones are so similar that there are no stains that can bind to some and not others, a process often used by researchers to differentiate cell types under a microscope.
Imaging the living retina allowed Williams to shine light directly into the eye to see what wavelengths each cone reflects and absorbs, and thus to which color each is responsive. In addition, the technique allows scientists to image more than a thousand cones at once, giving an unprecedented look at the composition and distribution of color cones in the eyes of living humans with varied retinal structure.
Each subject was asked to tune the color of a disk of light to produce a pure yellow light that was neither reddish yellow nor greenish yellow. Everyone selected nearly the same wavelength of yellow, showing an obvious consensus over what color they perceived yellow to be.
Once Williams looked into their eyes, however, he was surprised to see that the number of long- and middle-wavelength cones--the cones that detect red, green, and yellow--were sometimes profusely scattered throughout the retina, and sometimes barely evident. The discrepancy was more than a 40:1 ratio, yet all the volunteers were apparently seeing the same color yellow.

A new high-resolution map of Mars’s magnetic field indicates that the red planet’s crust once moved like present-day Earth’s.
The map was pieced together from observations of Mars’s magnetic field taken by NASA’s Mars Global Surveyor (MGS). It reveals that the planet’s surface was shaped in the same manner as Earth’s--by giant crustal plates pulling apart or smashing together, space.com reported.
In 1999, MGS provided a glimpse of this type of activity over one region in the Southern Hemisphere. The new map is based on four years of data and covers the entire planet, yielding evidence that some of the main features on Mars, such as the Tharsis volcanoes and the Valles Marineris, were created in part by the same processes that created the Hawaiian Islands and Grand Canyon on Earth.
Crustal plates sit on top a layer of molten rock called the mantle, and when they slide around, they produce a pattern scientists refer to as “striping.“ As molten rock rises from the mantle, it breaks through the crust, pushing the plates apart. Once the molten rock reaches the surface, it cools and is magnetized in the direction of the planet’s magnetic field.
Later on, this new surface will likewise be split apart by more rising material.
On Earth, the magnetic field flips direction a few times every million years, so a flow that rises and cools in one period may have a different magnetic orientation to the one next to it. These alternating stripes are proof of both a strong magnetic field and tectonic activity.
Activity like this is widespread on Earth--particularly along the Mid-Atlantic Ridge--but had never been confirmed on Mars until this latest study.
“This map lends support to and expands on the 1999 results,“ said Norman Ness of the Bartol Research Institute at the University of Delaware. Confirming that Mars experienced plate tectonics at some point in its history helps explain some of the mysteries of Mars geology. The Tharsis volcanoes --which include the largest volcano in the solar system, Olympus Mons--lie in a straight line, but until now, scientists couldn’t say why.
With the new map, it is likely that they were formed from the motion of a crustal plate sitting over a “hotspot“ in the mantle, just as the Hawaiian Islands are thought to have formed.
The Valles Marineris is a large canyon six times as long and eight times as deep as the Grand Canyon. It is 2,800 miles long, 125 miles wide, and nearly seven miles deep.
Its features resemble what a tectonic plate being pulled apart would look like on Earth, and its stripe pattern is oriented in a way that scientists would expect from the plate motions implied by the new map.

Damage to a nest of Formosan subterranean termites brings hoards of workers and soldiers with dark, oval-shaped heads scrambling to repair the hole.

The Formosan subterranean termite is a pest so formidable that even a hurricane can’t bring it down, according to ABC News website.
Known as “super termites,“ the insects can hold their breath for up to 16 hours underwater, they’re good at finding tiny air pockets in the soil to breathe once grounds are soaked and they can retreat to aboveground portions of their elaborate nests to wait out a storm.
That said, this hurricane season in New Orleans appears to have struck at least a temporary blow to the city’s infestation problem. Before Hurricane Katrina and subsequent flooding in the city, New Orleans and Lake Charles, La., hosted the most serious infestations of this voracious termite in the nation. Early testing suggests Katrina penetrated some of these populations.
But experts say any immediate drop in the insect’s population will likely be met by a termite boom in the years to come. And now the insect has the perfect opportunity to spread.
“We have found dead termites, so it appears many have drowned,“ said Gregg Henderson, an entomologist and termite guru at Louisiana State University, who dug up previously buried test crates packed with old wood last week in New Orleans to see how the insect’s numbers were looking.
Since Hurricane Katrina devastated the region, Henderson explains, the area has become termite heaven--a virtual termite buffet--packed with moist debris, including soaked homes and downed trees. This material provides the insect with its main food: cellulose.
What’s more, as cleanup continues, infected debris could be transported to other regions and cause the infestation to spread.
The Formosan subterranean termite got its original foothold in the United States by hitching a ride with people. It’s believed the bugs arrived aboard military transport ships returning from Asia after World War II.
Since then, the insects have spread to much of the Southeast as people reused old railroad ties and telephone poles that had been infested. While the insect has spread, it has not saturated most of the Southeast -- yet.
At entomologists’ urging, the Louisiana Department of Agriculture and Forestry imposed a quarantine on Oct. 3 for the termite in infested parishes. This bars anyone from selling or reusing wood from the area until it is fumigated.
Henderson is confident the quarantine will work to limit spreading of infested material for commercial purposes, but preventing individuals from, say, moving their old couch to their new home in Atlanta, is more problematic.

By comparing the human genome with that of the chimpanzee, man’s closest living relative, researchers have discovered that chunks of similar DNA that have been flipped in orientation and reinserted into chromosomes are hundreds of times more common in primates than previously thought.
According to Eurekalert, these large structural changes in the genome, called inversions, may account for much of the evolutionary difference between the two species. They may also shed light on genetic changes that lead to human diseases.
Although humans and chimpanzees diverged from one another genetically about six million years ago, the DNA sequences of the two species are approximately 98 percent identical.
Given the 2005 publication of the draft chimpanzee genome sequence, researchers can now readily identify the differences between the human and chimp genomes. These differences lend insight into how primates evolved, including traits specific to humans.
Senior author Stephen W. Scherer is a HHMI international research scholar, a senior scientist in the Genetics and Genomic Biology Program at the Hospital for Sick Children in Toronto, Canada, and an associate professor of molecular and medical genetics at the University of Toronto.
Instead of identifying sequence changes between the two genomes at the base-pair level, Scherer focused his research on large structural variations in chromosomes between humans and chimps, specifically genetic inversions. Inversions can disrupt the expression of genes at the point where the chromosome breaks, as well as genes adjacent to breakpoints.
According to Scherer, prior to this research, only nine inversions between humans and chimps had been identified. Using a computational approach, Scherer’s group identified 1,576 presumed inversions between the two species, 33 of which span regions larger than 100,000 base pairs--a sizeable chunk of DNA. The average human gene is smaller, only about 60,000 bases in length.
Scherer’s team experimentally confirmed 23 out of 27 inversions tested so far. Moreover, by comparing the chimp genome with its ancestor, the gorilla genome, they determined that more than half of the validated inversions flipped sometime during human evolution.
Perhaps even more interesting than the abundance of inversions that Scherer’s group unveiled was their discovery that a subset of the inversions are polymorphic--taking different forms--within humans, meaning that the human genome is still evolving. When the 23 experimentally confirmed inversions were tested against a panel of human samples, the scientists found three inversions with two alleles or pairs of genes displaying the human inversion in some people, whereas others had one allele of the human inverted sequence and one allele of the normal sequence in chimps.
Having one allele with an inversion and one allele without represents a ticking time bomb in genetic terms, Scherer said, since these alleles may improperly align and recombine during replication, ultimately causing DNA deletions or a loss of DNA that subsequent generations inherit. Scherer’s prior research on Williams-Beuren syndrome, a disease caused by DNA micro-deletions, identified a significantly higher incidence of inversions among the parents of afflicted patients.
Interestingly, one of the inversions that Scherer identified as polymorphic in his current paper includes a gene known to be involved in colorectal cancer. Whether individuals polymorphic for this inversion are at increased risk for the development of colorectal cancer is not yet known.
Scherer determined that about 10 percent of the presumed inversions either contain a complete gene within the flipped region, constitute a flipped region within a gene, or cause a breakpoint somewhere within a gene. These inversions represent prime targets for disease gene discovery, which Scherer’s team is exploring further.

Nearly half of the world’s coral reefs may be lost in the next 40 years unless urgent measures are taken to protect them against the threat of climate change, according to LiveScience
The Swiss-based organization called for the establishment of additional marine protected areas to prevent further degradation by making corals more robust and helping them resist bleaching.
“Twenty percent of the earth’s coral reefs, arguably the richest of all marine ecosystems, have been effectively destroyed today,’’ said Carl Gustaf Lundin, head of the agency’s marine environment program who helped write the report “Coral Reef Resilience and Resistance to Bleaching.’’
“Another 30 percent will become seriously depleted if no action is taken within the next 20-40 years, with climate change being a major factor for their loss,’’ he said in a statement.
Coral bleaching is caused by increased surface temperatures in the high seas and higher levels of sunlight caused by climate change. As temperatures rise, the algae on which corals depend for food and color die out, causing the coral to whiten, or “bleach.’’
Prolonged bleaching conditions over ten weeks can eventually lead to the death of the coral.
“Current predictions are that massive coral bleaching will become a regular event over the next 50 years,’’ Lundin said.
In its report, the organization said that marine parks reduce the stress on coral reef ecosystems by reducing the impact of pollution and overfishing.
The report also recommends a strategy for the establishment of a global marine park network in the face of climate change, covering all important marine ecosystems including coral reefs.
Other key strategies to enable coral reefs to be more resilient to bleaching are sustainable fisheries management and integrated coastal management, the report found.
“Destructive fishing practices such as blast or poison fishing can make coral reef more vulnerable to bleaching,’’ said The Nature Conservancy’s Rod Salm in a statement. “It can decrease coral cover or deplete fish populations that are important for the coral reef ecosystem.’’