This false-color image, captured by Mars Exploration Rover Opportunity May 6, 2007, shows Cape St. Vincent, one of many promontories that jut out from the walls of Victoria Crater on Mars.

Having explored Mars for over 3 years during missions originally designed for three months, NASA’s Mars rovers are facing perhaps their biggest challenge.
For nearly a month, a series of severe martian summer dust storms has affected rover Opportunity and, to a lesser extent, its companion, Spirit. The dust in the atmosphere over Opportunity has blocked 99 percent of direct sunlight to the rover, leaving only limited diffuse sky light to power it. Scientists fear the storms might continue for several days, if not weeks.
“We’re rooting for our rovers to survive these storms, but they were never designed for conditions this intense,“ said Alan Stern, associate administrator of NASA’s Science Mission Directorate in Washington.
The rovers use electric heaters to keep some of their vital core electronics from becoming too cold. If the sunlight continues to be cut back for an extended period, the rovers will not be able to generate enough power to keep themselves warm and operate at all, even in a near-dormant state, Astronomy.com reported.
Before the dust storms began blocking sunlight last month, Opportunity’s solar panels had been producing about 700 watt hours of electricity per day, enough to light a 100-watt bulb for seven hours. When dust in the air reduced the panels’ daily output to less than 400 watt hours, the rover team suspended driving and most observations, including use of the robotic arm, cameras and spectrometers to study the site where Opportunity is located.
NASA engineers are taking measures to protect the rovers, especially Opportunity, which is experiencing the brunt of the dust storm. The rovers are showing robust survival characteristics. Spirit, in a location where the storm is currently less severe, has been instructed to conserve battery power by limiting its activities.
“We are taking more aggressive action with both rovers than we needed before,“ said John Callas, project manager for the twin rovers at NASA’s Jet Propulsion Laboratory in Pasadena, California.
By Opportunity’s 1,236th martian day last week, driving and all science observations had already been suspended. The rover still used more energy than its solar panels could generate on that day, drawing down its battery.
This is the first time either of the rovers has been told to skip communications for a day or more in order to conserve energy. Engineers calculate that skipping communications sessions should lower daily energy use to less than 130 watt hours.
A possible outcome of this storm is that one or both rovers could be damaged permanently or even disabled. Engineers will assess the capability of each rover after the storm clears.

University of Southern California researcher Songtao Shi and his colleagues experiment with stem cells that can regenerate bone and skin tissue.
If Songtao Shi’s latest discovery ever reaches Southern California clinics, “Oh, she’s had a stem cell job,“ may one day replace the ubiquitous “She’s had work done“ as a tabloid euphemism for the efforts of the well-heeled to turn back the clock.
Shi, a researcher at USC’s Center for Craniofacial Molecular Biology, and colleagues at dental schools in Korea and China have discovered that mesenchymal stem cells (MSCs) are capable of regenerating facial bone and skin tissue in mouse and swine models.
While there remains much to learn, their work published in the April 2007 issue of the journal Stem Cells points to a future in which MSCs become a plastic surgeon’s weapon of choice for everything from repairing severe facial disfigurement to removing wrinkles.
“It’s very exciting,“ Shi said. “It is fundamentally different from current techniques. At this point it is just a concept, but in the future it may change the way we do plastic surgery.“
The research employs MSCs derived from two sources. To construct orofacial bone tissue, Shi and colleagues utilized MSCs extracted from human bone marrow and transplanted them into the frontal skull, Science Daily reported.
After eight weeks, a pronounced expansion of the skull was readily visible. Tests of this new tissue showed it was healthy and fully integrated into existing bone.
Even more remarkably, the new bone tissue showed evidence of homeostasis Ð the process by which red and white blood cells are created.
“This is very important. This is not an implant. This is an extension of the body. These cells have the ability to work with and organize existing cells and tissue,“ Shi said.
Their second technique relied on MSCs derived from the periodontal ligament. Introducing these stem cells into the facial wrinkles of a mouse model, Shi and colleagues found that the periodontal ligament MSCs eliminated the wrinkles through the production of new collagen fibers.
Shi hopes to improve his initial results by experimenting with delivery methods Ð the stem cells have varying degrees of success based upon the material used to serve as a scaffold. He also hopes to investigate the potential of autologous stem cells, those derived from the animal’s own tissue, to improve clinical results.
“There are many potential applications for these techniques,“ Shi said. “There is still so much that we don’t understand fully. It is clear that we need more studies to explore new therapies and improve clinical consequences.“

Many scientific studies support the benefits of lowering low-density lipoprotein (LDL) cholesterol, and achieving low LDL cholesterol levels is one of the most important steps in preventing heart disease. New research, however, provides evidence for an association between low LDL levels and cancer risk.
The researchers set out to understand how and why statins cause side effects, particularly damage to the liver and muscle cells. The study findings support taking multiple medications rather than high-dose statins to minimize those side effects, Science Daily reported.
The researchers did not expect to find the increased cancer risk (one additional incident per 1,000 patients) from low LDL levels, and additional studies have already begun to investigate this potential risk further.
“This analysis doesn’t implicate the statin in increasing the risk of cancer,“ said lead author Richard H. Karas, M.D., F.A.C.C., professor of medicine at Tufts University School of Medicine. The researchers found one additional incident of cancer per 1,000 patients with low LDL levels when compared to patients with higher LDL levels.
Researchers assessed absolute change and percentage of change in LDL reduction and the resulting achieved LDL levels in relation to rates of newly diagnosed cancer in each treatment arm. They also looked at the relationship between low, intermediate and high doses of statins and rates of newly diagnosed cancer. Although they did not find a relationship between percent of change and absolute change in LDL levels, they observed higher rates of newly diagnosed cancer among patients with lower achieved LDL levels. In addition, the new cancers were not of any specific type or location.
Recent data from large-scale statin trials have shown that more intensive LDL lowering can provide significant cardiovascular benefits to higher-risk patients. In response to these findings, recent national guidelines have advocated for lower LDL goals and higher doses of statins to reach them. However, informal observations linking intensive LDL lowering and higher incidence of reported health problems, including liver and muscle toxicity and cancer, has introduced some concern over the safety of such treatments.
These concerns in part prompted the current study. However, the current findings are not definitive, as limitations of the study show. Researchers performed their analysis from summary data taken directly from published manuscripts of each trial. An analysis based on data for each individual patient would have yielded more specific and potentially more compelling results, said Dr. Karas.
A link between LDL lowering and liver or muscle irritation was not found. However, liver toxicity levels increased with higher statin dosage. Based on their findings, the researchers concluded that moderate-dose therapy with multiple medications including statins may prove to be preferable to high-dose therapy with statins alone. Dr. Karas emphasized that patients are advised to continue their statin treatments and, as always, consult their doctor before discontinuing use of any medication.

Most cases of Alzheimer's develop in those aged 65 or over--affecting about one in 20.

Scientists have successfully tested a treatment in mice that stops the progression of Alzheimer’s and even sends the disease into reverse.
It will be several years before the experimental treatment can be used on humans but one advantage is that it works at a very early stage. It is hoped the breakthrough could one day enable doctors to stop the disease in its tracks before patients suffer the worst effects.
The treatment is a protein, specifically designed for the job, based on the three-dimensional structure of two other proteins involved in the progression of the disease. It works by sticking to one of these proteins so that it cannot bind with the other--a step that triggers a succession of biochemical events that lead to the death of the nerve cell and ultimately to the patient’s symptoms.
Most cases of Alzheimer’s develop in those aged 65 or over--affecting about one in 20. But by 85 nearly half will have the disease. There are currently about 500,000 Alzheimer’s patients in the UK, Guardian said.
Scientists studying the disease have established that Alzheimer’s patients produce abnormally large quantities of the proteins amyloid--which forms the plaques in the brain typical of the disease--and ABAD. When amyloid and ABAD combine this triggers a cascade of changes leading to the death of the nerve cell.
The researchers worked out how to disrupt this interaction in mice which are genetically engineered to over-produce these proteins in the same way as Alzheimer’s patients. They designed a “decoy“ protein that would stick to the amyloid and prevent it from binding to ABAD. When they gave it to mice they found the animals did not develop the disease and changes that had already happened were reversed.
“The work is now being continued to try and refine the inhibitor into a potential drug,“ said Frank Gunn-Moore, part of the team at St Andrew’s University. “If it gets that far it will have to undergo several years of human tests before it could be used on patients.“

Great Bustard

The world’s heaviest flying bird, the Great Bustard, has laid its first eggs in Britain in 175 years, conservationists who reintroduced the species here said.
The Great Bustard Group (GBG) said a female of the species, which can weigh up to 40 pounds (18.1 kilogrammes) and has a wing span of up to eight feet (2.4 metres), laid two eggs earlier this year in Wiltshire, southwest England.
But although the eggs were incubated, abandoned and later found to be infertile, GBG director David Walters said it was a major achievement and signs that a breeding programme, first started nine years ago, was working, AFP reported.
“It had been thought 2008 would be the first year that nesting activity would be seen and it is a tremendous boost to have this happening earlier,“ he said in a statement.
“Although males were seen displaying to females this spring, it is understood that males have to be about five years old before they can breed.“
It is thought the eggs were infertile because the male had not reached maturity.
“Significantly, only birds in good condition produce eggs. Hungry or stressed wild birds do not produce eggs so this is a strong indication of the success of the project,“ Walters added.
The announcement that eggs had been laid -- the first in the wild since 1832--was delayed because of fears of egg thieves and disturbance from bird watchers and the location is being kept secret.
The Great Bustard, known as a shy and secretive bird, became extinct in Britain in the 1840s due to hunting. There are thought to be only about 35,000 in the world.
Birds from Russia were reintroduced to Britain in 2004 under a programme licenced by the government after attempts to breed chicks in captivity and release them failed.
A number of birds are released on Salisbury Plain in Wiltshire, south-west England, in the British autumn and winter and return there each spring.

Only chance kept us from looking like our crag-browed Neanderthal cousins. A statistical analysis suggests that the skull differences between the two species stems not from positive natural selection but from genetic drift, in which physical features change randomly, without an environmental driving force.
Some anthropologists had put the cranial differences down to natural selection arising from Neanderthals’ use of their teeth as tools, for instance, or from modern humans’ speech. To test if genetic drift could have been responsible instead, Timothy Weaver of the University of California, Davis, and colleagues compared 37 measurements of the skulls of various modern human populations with those of Neanderthals. After a comparison of the mean divergence between Homo sapiens and Neanderthals and the mean divergence among groups of modern humans, they conclude that genetic drift is responsible, NewScientist.com said.
The development of culture weakened the influence of the environment upon both Neanderthals and modern humans, says Weaver. But ultimately the two species drifted apart genetically when they became isolated from each other.

As any child knows, to answer the question “how many,“ one must start by adding up individual objects in a group. This cognitive ability is shared by animals as diverse as humans and birds.
Surprisingly, the exact brain mechanisms responsible for this process remained unknown until now. In PLoS Biology, Jamie Roitman, Elizabeth Brannon, and Michael Platt from the University of Illinois at Chicago now report novel evidence for the existence of “accumulator neurons,“ which respond to increasing numbers of items in a display with progressively increasing activity, in the parietal cortex of monkeys, Science Daily said.
The authors focused on the parietal cortex based on evidence that damage to this brain region disrupts basic mathematical skills, and is activated during functional imaging studies when people perform basic computations. To understand how parietal cortex contributes to numerical behavior, the authors studied the activity of neurons in the lateral intraparietal area in monkeys while they looked at arrays of dots on a computer screen.
Parietal neurons responded with progressively increasing activity as the total number of elements in the display was varied across a wide range of values (2-32). These neurons resemble “accumulator neurons“ that have been suggested to serve the first stage in counting.
This information could be used by other neurons that respond best for a particular cardinal number, such as “4,“ as have been reported in prior studies. These findings support computer models that separate the processes of summing and numerical identification, and may also explain the fact that parietal cortex damage causes both numerical and spatial confusion.
Neurons in the lateral intraparietal area in monkeys respond in a graded fashion to the number of items in a visual array during a delayed saccade task, suggesting that the neurons “sum up“ individual elements to represent accumulated magnitude.