NASA's Fermi telescope discovers first gamma-ray-only pulsar

---

---

Clouds of charged particles move along the pulsar's magnetic field lines (blue) and create a lighthouse-like beam of gamma rays (purple) in this illustration.
Click here for more information.

---

WASHINGTON -- About three times a second, a 10,000-year-old stellar corpse sweeps a beam of gamma-rays toward Earth. Discovered by NASA's Fermi Gamma-ray Space Telescope, the object, called a pulsar, is the first one known that only "blinks" in gamma rays.

"This is the first example of a new class of pulsars that will give us fundamental insights into how these collapsed stars work," said Stanford University's Peter Michelson, principal investigator for Fermi's Large Area Telescope in Palo Alto, Calif.

The gamma-ray-only pulsar lies within a supernova remnant known as CTA 1, which is located about 4,600 light-years away in the constellation Cepheus. Its lighthouse-like beam sweeps Earth's way every 316.86 milliseconds. The pulsar, which formed about 10,000 years ago, emits 1,000 times the energy of our sun.

A pulsar is a rapidly spinning neutron star, the crushed core left behind when a massive sun explodes. Astronomers have cataloged nearly 1,800 pulsars. Although most were found through their pulses at radio wavelengths, some of these objects also beam energy in other forms, including visible light and X-rays. However, the source in CTA 1 only pulses at gamma-ray energies.

"We think the region that emits the pulsed gamma rays is broader than that responsible for pulses of lower-energy radiation," explained team member Alice Harding at NASA's Goddard Space Flight Center in Greenbelt, Md. "The radio beam probably never swings toward Earth, so we never see it. But the wider gamma-ray beam does sweep our way."

Scientists think CTA 1 is only the first of a large population of similar objects.

"The Large Area Telescope provides us with a unique probe of the galaxy's pulsar population, revealing objects we would not otherwise even know exist," says Fermi project scientist Steve Ritz, also at Goddard.

The pulsar in CTA 1 is not located at the center of the remnant's expanding gaseous shell. Supernova explosions can be asymmetrical, often imparting a "kick" that sends the neutron star careening through space. Based on the remnant's age and the pulsar's distance from its center, astronomers believe the neutron star is moving at about a million miles per hour -- a typical speed.

Fermi's Large Area Telescope scans the entire sky every three hours and detects photons with energies ranging from 20 million to more than 300 billion times the energy of visible light. The instrument sees about one gamma ray every minute from CTA 1, enough for scientists to piece together the neutron star's pulsing behavior, its rotation period, and the rate at which it is slowing down.

A pulsar's beams arise because neutron stars possess intense magnetic fields and rotate rapidly. Charged particles stream outward from the star's magnetic poles at nearly the speed of light to create the gamma-ray beams Fermi sees. Because the beams are powered by the neutron star's rotation, they gradually slow the pulsar's spin. In the case of CTA 1, the rotation period is increasing by about one second every 87,000 years.

"This observation shows the power of the Large Area Telescope," Michelson said. "It is so sensitive that we can now discover new types of objects just by observing their gamma-ray emissions."

Original here

Scientists Use Light To Control Proteins

The scientists attached a light-sensing protein (sensor) from the oat plant to an enzyme from E. coli. When they shined white light (stimulus) on the sensor, the enzyme's acitvity increased (output). (Credit: Benkovic lab, Penn State)

A team of researchers from Penn State and the University of Texas Southwestern Medical Center has discovered a way to use light to control certain proteins that catalyze biochemical reactions.

"This is one of the first examples of someone successfully controlling the activity of a protein using light," said Stephen Benkovic, Penn State Evan Pugh Professor of Chemistry, holder of the Eberly Family Chair in Chemistry, and one of the team's leaders. "The technology one day could be expanded to have multiple uses, including the ability to turn off the activities of some disease-causing proteins in the cell," he said.

The team's results will appear in the 17 October issue of the journal Science.

In their experiment, the scientists designed a hybrid protein by inserting a light-sensing protein from an oat plant into an enzyme -- a type of protein that catalyzes biochemical reactions -- from the bacterium E. coli. After engineering the two components together, the researchers found that the enzyme's activity could be manipulated by shining a light on the light-sensing protein, which the scientists refer to as a "domain." "The technology works like a light switch," said Benkovic. "When we shine a light on the light-sensing domain, the enzyme's activity increases, and when we shut the light off, the enzyme's activity decreases."

According to Jeeyeon Lee, a postdoctoral scholar in the Penn State Department of Chemistry and one of the paper's authors, the team had to consider a number of factors when designing the hybrid protein, including the protein's shape, or what is referred to as its conformation. "The conformation of a protein is important in determining its function," she said. "Without the proper conformation, our protein would not have responded to the light."

Another important factor that the team had to consider was the proper location on the enzyme into which the light-sensing protein from the oat plant would be inserted. Vishal Nashine, also a postdoctoral scholar in the Department of Chemistry and an author of the paper, said the team was surprised to find that the switch worked only when they attached the light-sensing domain to the enzyme at a particular site. The switch did not operate when they attached the molecule to other locations on the enzyme. "The fact that the switch worked only when the light-sensing domain was attached to the enzyme at a specific site suggests that a unique network is active at that site through which signals, such as those responding to light, are transmitted," he said.

The successful site was located, among more than a hundred different possibilities, using a computational algorithm called the Statistical Coupling Analysis (SCA), which was pioneered by Rama Ranganathan, a professor of pharmacology at the University of Texas Southwestern Medical Center and one of the paper's leading authors.

The team's future research will investigate how the signal triggered by the light was transmitted from the light-sensing domain to the enzyme. "It is not yet clear how this process works," said Benkovic. "So far, the effect has been small, but we plan to optimize the technology to see if we can use light to modulate the enzyme's activity in alternative ways."

Other authors of this paper from the University of Texas Southwestern Medical Center include William Russ, an assistant professor of pharmacology, who was responsible for locating the site on the enzyme into which the light-sensing protein was successfully inserted, and Madhusudan Natarajan, an assistant professor of pharmacology, Tina Vo, a senior technician, and Michael Socolich, a senior technician, who worked together to build the genes for the hybrid proteins.

Original here

New solar tech is over the rainbow

Radiohead already know the tremendous power that lurks 'In Rainbows'

Zoom

<>

Ohio State University chemists have created a new material that could revolutionise photovoltaic solar panels.

Today's solar cell materials are sensitive to only a limited range of frequencies, so they can only capture a small fraction of the energy contained in sunligh.

The new hybrid material - an electrically conductive plastic combined with metals including molybdenum and titanium - is the first that is sensitive to all the colours in the rainbow, allowing it to absorb all the energy contained in visible light at once.

Not only is the hybrid material more sensitive than normal solar panels, it also generates much more charge (more free electrons) than the researchers were expecting.

Easily excited

"This long-lived excited state should allow us to better manipulate charge separation," said Professor Malcom Chisholm, chair of the Ohio State's Chemistry Department.

To design the as-yet-unnamed hybrid material, Chisholm explored different molecular configurations on a supercomputer before synthesizing molecules of the new material in a liquid solution.

However, he warns that it could be years before high-power hybrid solar panels find their way onto our roofs. Until then, we're stuck with today's traditional silicon panels - and hopefully the more efficient thin-film technologies coming soon.

By Mark Harris

Original here

Agriculture unaffected by pollinator declines

Global crop yields have not suffered even though key insect populations have shrunk.

Anna Petherick

Crops may not need quite so many bees for pollination after all.Punchstock

Bees and many other insects may be in decline almost everywhere — but agriculture that depends on pollinators has been surprisingly unaffected at the global scale.

That's the conclusion of a study by Alexandra Klein at the University of California, Berkeley, and her colleagues. Using a data set of global crop production — maintained by the Food and Agriculture Organisation of the United Nations (FAO) — which spanned 1961 to 2006, they compared the yields of crops that require pollinators with those that don't.

They found that crop yields for both crop types have gone up consistently, seeing average annual growth rates of about 1.5%. There was also no difference when the researchers split the data into crops from developing countries and crops from developed countries.

And when the researchers compared crops that are cultivated almost exclusively in tropical regions, they found no difference between the success of insect-pollinated crops — such as oil palm, cocoa and the Brazil nut — and those crops that need only the breeze to spread their pollen.

Underplayed, overplayed

The results, published in Current Biology¹, are surprising because several previous studies have found very large impacts at local scales. Taylor Ricketts, head of conservation group WWF's conservation science programme, and his colleagues, reported in 2004 that pollinators increased coffee yields by 20% on plants growing a kilometre or less from forests in Costa Rica².

In 2005, a team led by Jacobus Biesmeijer of the University of Leeds, UK, found evidence of a drop-off in bee diversity in the United Kingdom and the Netherlands³. This coincided with a decline in outcrossing plant species relative to other sorts of plants.

And worries about a pollination crisis have found their way into international politics, most prominently with the establishment of the International Initiative for the Conservation and Sustainable Use of Pollinators (IPI) at a United Nations meeting in 2000.

But some scientists think that the pollinator crisis is overplayed. Jaboury Ghazoul, a plant ecologist at ETH Zurich, Switzerland, has argued that it is driven mainly by reported declines of crop-pollinating honeybees in North America and bumblebees and butterflies in Europe⁴.

Other data show that native pollinator communities elsewhere exhibit mixed responses to environmental change, and Ghazoul says that few staple food crops depend on insect pollinators.

"When the IPI was established, there was some disagreement about how much pollinators are declining," says Linda Collette, a senior officer on crop associated biodiversity at the FAO, which oversees the IPI programme.

Hidden threat

Klein says her findings do not necessarily negate that idea that the world is in the throes of a pollination crisis. The data might hide how farmers have adapted to the problem, she suggests.

For example, in almond pollination, many growers move honeybees into their orchards and use pheromones to stimulate foraging activity, she says. Some even place compatible pollen in the bees' hives so that they transport it to the desired variety of almond. And many passion-fruit growers in Brazil now pollinate crops by hand.

For the FAO, the increasing reliance on farmworkers rather than insects may not represent a crisis. "At the end of the day, what's important to the FAO is crop production," says Collette. "There may be labour costs involved in pollinating crops but there could also be market benefits — if the fruits are better from that, for instance."

However, Klein points out that a sudden drop in crop yields could be just around the corner. "There could be a more widespread threshold effect coming," she says, "especially if the honeybee problems get worse in places like California."

This may be more likely as farmers all over the planet start to fill ever more hectares with pollinator-dependent crops, which contributed 8.4% of total agricultural production in the developed world in 1961 but 14.7% in 2006. "We assume that the trend will continue as many biofuels crops, such as canola, oil palm and jatropha, are pollinator-dependent plants," says Klein.

Original here

“Hippie” Apes Leave the Commune, Go Hunting

by Lisa Lombardi

Deep in the forest, south of the river Congo, live the free-lovin’ relatives of the common chimpanzee, the bonobo. Previously known as the pygmy chimpanzee, the bonobo spend their days getting frisky in the forest, weaving hemp hammocks, and living among an ever-present haze of sandalwood smoke.

Image courtesy of USAID

Well, maybe not those last two, but they have developed a reputation as being the peaceful hippies of the chimpanzee world. After five years of observation, however, primate researchers stationed in the Democratic Republic of Congo have made a startling discovery about these animals: Not only do they hunt and kill, they hunt and kill other monkeys, just like the common chimpanzee.

Dude. Not cool.

The bonobo society is one where females are the head honchos, and their most frequent activity is getting down (if you know what I mean). From saying hello, to solving an argument, to celebrating a resolved conflict—it’s all about the nookie for bonobos. Or so we thought.

In LiuKuotale, Salonga National Park, Gottfried Hohmann’s team of researchers spied a group of bonobos successfully hunting primate prey three separate times. As the team reported in the October 14th issue of Current Biology, two other, unsuccessful, hunting attempts were observed as well. Before this, Hohmann’s team suspected that the bonobo were hunting monkeys based on fresh fecal remnants, but were unsure if the primates were simply stealing another animal’s kill.

As disheartening as it is to picture a little chimp chowing down on his cousin, this news shakes up a lot more than just your stomach. It was thought that aggression, meat consumption, and hunting were thought to be associated with male dominance, as is the case in common chimpanzee society; the bonobo’s relative lack of hunting and meat-eating was attributed to their female-dominant society. This discovery disputes the idea that male dominance and aggression must be linked to hunting.

Chimpanzees—both common and bonobo—are the closest relatives to Homo sapiens, sharing more than 98% of our genes. The close link between humans and chimpanzees make observations such as Hohmann’s especially important.

Original here

Obese people get less satisfaction from food

By Richard Alleyne

Obese people may overeat because they experience less satisfaction from the taste of food, scientists believe.
New research has found that the taste of food produced less of a pleasureable sensation in the brains of those who are obese and that they may have to eat more to compensate.

In particular the eating of tasty food produced less dopamine in the brain, a hormone which promotes positive feelings of happiness and lowers anxiety.

Scientists feel that it might be that overweight people have to eat more or "comfort eat" in order to produce the same feelings of contentment.

"Although recent findings suggested that obese individuals may experience less pleasure when eating, and therefore eat more to compensate, this is the first prospective evidence for this relationship," said Eric Stice, lead author and a psychology researcher at The University of Texas.

His team, which included scientists from Yale and Oregon, scanned the brains of 76 volunteer women in two studies as they drank chocolate milkshakes.

They found that the women who were obese or prone to being obese had deficiencies in the "reward circuitry" or striatum of their brains.

When checking a year later it was discovered that those with poor "reward circuitry" were more likely to have gained weight even if they shown no signs of obsesity at the beginning of the study.

Dr Stice found obese people showed less activation in the striatum relative to lean people. He also found individuals with a blunted response were more likely to show unhealthy weight gain.

The researchers believe that the findings could help predict who is prone to weight gain in the future and provide treatment and advice to help them avoid it.

"The study is novel because it is the first to use brain response to food to try to predict future weight gain," said Dana Small, associate professor at Yale.

Original here

Volcanoes May Have Provided Sparks Of First Life

Scripps professor of marine chemistry Jeff Bada produces an electrical stark in an experimental apparatus to show how the atmospheric conditions during volcanic eruptions may have led to early life on Earth. (Credit: Scripps Institution of Oceanography, UC San Diego)

New research suggests that lightening and volcanoes may have sparked early life on Earth. Researcher Jeffrey Bada at Scripps Institution of Oceanography at UC San Diego and colleagues reanalyzed Stanley Miller's classic origin of life experiment, offering a new analysis on how the essential building blocks of life may have arisen from volcanic eruptions.

Bada, Scripps professor of marine chemistry and graduate student of Miller's in the Chemistry Department at the UC San Diego in 1960, preserved Miller's original chemical samples. Bada along with lead author Adam Johnson, Indiana University graduate student and colleagues, reanalyzed the samples to determine if new chemical compounds could be detecting using modern equipment. The paper, "The Miller Volcanic Spark Experiment," is published in the Oct. 17 issue of the journal Science.

"We believed there was more to be learned from Miller's original experiment," said Bada, co-author in the paper. "We found that a modern day version of the volcanic apparatus produces a wider variety of compounds."

Miller's classic "primordial soup" experiment, published in Science in 1953, is still widely used today in high school chemistry labs to mimic chemical reactions that occur in vapor-rich volcanic eruptions. The experiment circulated methane, ammonia, water vapor and hydrogen in a closed experiment, simulating the earth's early atmosphere and sent a lightning-like spark through it. Over a series of days, organic compounds formed in the mixture, demonstrating how Earth's primitive atmosphere may have given rise to life.

It is commonly thought that early Earth was comprised of many small volcanic islands. This study suggests that lightning and the release of gases associated with these volcanic eruptions could have produced the necessary chemical components to give rise to early life.

Bada's lab is the first to perform follow up studies using Miller's original apparatus and chemicals samples, which were discovered following Miller's death in 2007. Researchers reanalyzed 11 of the original samples using contemporary analytical chemistry techniques and produced 22 amino acids, the building blocks of proteins, 10 of which had not been identified previously by Miller.

"Historically, you don't get many experiments that might be more famous than these; they redefined our thoughts on the origin of life and showed unequivocally that the fundamental building blocks of life could be derived from natural processes," said lead author Adam Johnson, a Indiana University graduate student with the NASA Astrobiology Institute team.

Original here

In downturn, solar industry sees bright days ahead

Posted by Martin LaMonica

SAN DIEGO--People in the solar industry are hopeful that the sun is a good place to put money these days.

To be sure, the financial crunch is rippling through even the fast-growing solar business: With falling house prices and general belt-tightening, consumers may be more reluctant to purchase solar panels, even if they want renewable electricity. And less available capital makes it difficult to finance large-scale projects, like corporate rooftop arrays or solar power plants.

But even with the gloomy economic outlook, the mood at this week's Solar Power International 2008 conference was decidedly upbeat.

The solar industry scored a major policy win, getting an eight-year extension to federal tax credits that tacked on more generous terms for homeowners.

And in a volatile investment environment, solar looks solid, purely from a financial point of view, many executives argued.

"I think there's a flight to quality and we believe there's a flight to solar because of that," said Tom Werner, the CEO of California-based solar panel manufacturer and installer SunPower. He noted that big solar projects over the past three or four years have created a track record of delivering expected financial returns.

"Now having said that...the credit markets are different and more measured. Banks are studying things more--the risk profiles and the balance sheets of companies," Werner said.

Long meetings with bankers
Discussion of the impact of the credit crisis and an economic slowdown at the conference alternated between "glass half full" and "glass half empty" perspectives.

The returns on solar projects for utilities and corporations have the advantage of being predictable and thus low-risk, said Bill Gross, CEO of a tech incubator called Idealab, which has spawned two solar companies targeting utilities--Energy Innovations and eSolar.

New technologies are bringing the cost of solar electricity closer to fossil fuel generation. And policies that encourage clean-energy production improve the financial return on big projects.

"It's so tight trying to beat the price of fossil fuel electricity. If you can cut the price at all with totally green energy, that's awesome," Gross said.

Sempra Energy, which builds and operates natural gas power plants, plans to invest billions in solar power plants in the coming years and expects to get about the same 10 percent return on the capital it typically gets, said Michael Allman, president and CEO of Sempra Generation. Because of the credit crunch, other firms may have a harder time than Sempra launching large projects, he said.

Matt Cheney, CEO of solar financing firm MMA Renewable Ventures, said solar company executives should expect to have long meetings with financial analysts and bankers as they seek to clamp down on risk and get better terms.

Click on the image to launch a photo gallery of products and solar installations from this week's Solar Power International conference.

(Credit: Martin LaMonica/CNET News)

"Historically, with respect to an impact, a shock like we've just experienced...takes about four years for things to settle down to the point where we can access capital at a rate that we were getting just six months ago," Cheney said during a CEO panel at the conference.

Other executives were more sanguine about the commercial market, noting that many funds set up to invest in renewable energy projects already have the money to invest.

Large deals are still "financeable" because the government incentives are generous and the demand strong, said Steven Chan, chief strategy officer at solar cell and panel manufacturer Suntech Power. Financiers, however, are likely to shift terms around.

A recession in the general economy can put a damper on solar in another way. If corporations see their tax bills drop because of falling earnings, they are less likely to purchase a rooftop solar array because they won't have the "tax appetite" to benefit from government incentives.

For solar companies themselves, the financial turmoil can stall plans to expand. Raising money on the stock market to build a new manufacturing facility, for example, is likely to be delayed as there are few initial public offerings.

Residential looks strong
For consumers, meanwhile, solar power looks more attractive than ever.

That's helped by the recently changed federal policy that gives homeowners a 30 percent tax credit on solar electric panels. Before, that credit was capped at $2,000.

"Without that cap, an average suburban home system could probably get a $9,000 tax credit on a system that might cost $30,000," Chan said. "It's real money now. The economics have gotten a whole lot better for the residential homeowner."

Significantly, the tax credits, which go into effect next year, were extended for eight years, a relatively long period for people to take advantage of them. Also, because solar cell efficiency continues to improve, homeowners can purchase more productive panels for about the same price, Chan said.

For a business that caters to environmentally minded consumers, talk at the Solar Power International conference was laced with hard-boiled financial terms like "tax equity investors" and "internal rate of return."

(Credit: Martin LaMonica/CNET News)

Shifting to an economically driven business is a very deliberate attempt to scale up solar adoption rapidly in the next five years, according to Julia Hamm, the executive director of the Solar Energy Industry Association.

Technology enhancements are helping bring the price of rooftop solar panels closer to the retail electricity rate, or "grid parity."

To lower the upfront cost barrier, start-ups like SolarCity and SunRun are offering financing options, such as leases, for consumers and small businesses. A handful of utilities, too, are getting into solar as well, a move that could make it more accessible.

All the numbers talk, though, is not to say that the environmental attributes of solar energy are insignificant. On the contrary, the existing federal and state policies place a value on renewable energy, executives said. The industry is lobbying for more policy initiatives, such as plans to modernize and bulk up the electricity grid.

Sempra Generation's Allman said that policies like a renewable portfolio standard, which mandates a certain percentage of renewable electricity generation, act as a market signal.

"Nobody would sign up for solar power today without the environmental attributes it offers. It's just too expensive," he said. "I think of it as two separate markets--one for brown power and one for green power."

Today's economic and political environment favors a push toward energy independence and environmental protection. For that reason, most solar company executives are bullish when they take a long-term view.

What's still unknown for solar--or other industries--is how badly the bruising from the current financial crisis will be.

"The price of electricity is determined in large part by the cost of capital," said Michael Ahearn, CEO of First Solar, which is recognized as having the cheapest solar panels. "We're in a temporary state where there is no real market functioning. The question is, where does the market reset?" he said during a panel.

Martin LaMonica is a senior writer for CNET's Green Tech blog. He started at CNET News in 2002, covering IT and Web development. Before that, he was executive editor at IT publication InfoWorld. E-mail Martin.

Original here