Butterflies Shed Light on How Some Species Respond to Global Warming

With global warming and climate change making headlines nearly every day, it could be reassuring to know that some creatures might cope by gradually moving to new areas as their current ones become less hospitable. Nevertheless, natural relocation of species is not something that can be taken for granted, according to Jessica Hellmann, Associate Professor at the University of Notre Dame Department of Biological Science in Notre Dame, Ind. By studying two species of butterfly, she and her team have found evidence suggesting that a number of genetic variables affect whether and how well a species will relocate.


Dr. Hellmann and her team have conducted a series of studies in which manipulating the temperature of the butterfly larvae's environment revealed how the two species might respond to global warming. She will discuss the team's work at the 2010 American Physiological Society's Intersociety Meeting in Westminster, Colo., August 4-7. The program is entitled, Global Change and Global Science: Comparative Physiology in a Changing World.

Duskywing and Swallowtail Butterflies: Coping with Change

The Notre Dame team studied the larvae -- or caterpillar phase -- of two butterfly species, the Propertius duskywing butterfly (Erynnis propertius) and the Anise swallowtail butterfly (Papilio zelicaon). These butterflies, both cold-blooded insects, were chosen because of their ecological differences but they live in the same ecosystem, allowing Dr. Hellmann to compare their responses in a single study.

The duskywing is a small butterfly that does not easily fly great distances and stays close to the West Coast of the United States. Because it does not fly great distances, the genetic makeup of the group does not spread very far. The species is also characterized by the fact that its larvae consume only the new leaves of oak trees, making it highly specialized. The Anise swallowtail, on the other hand, is a much larger butterfly, and can fly greater distances with greater ease. Its genes are more likely to be spread out over a larger range as its flies between the Rocky Mountains and westward to and around California. The swallowtail larvae eat an assortment of plants, which also helps to spread genes across its range.

The researchers performed a number of experiments between butterfly larvae from the northernmost ranges of their habitat (Vancouver Island, Canada; "northern larvae") and butterflies from the central part of their habitat (California and southwest Oregon; "central larvae"). They exposed each group of larvae to conditions simulating the other group's summer and winter climates and fed each group food grown in the other group's location, all with a special focus on how the northern larvae responded. According to Dr. Hellmann, understanding how populations at the edge of a species' range respond to warming will provide insight on whether the species will shift with climate change.

The team theorized that northern members of a species whose genes are more spread out, like the swallowtail's, might be pre-adapted to rising temperatures and could perhaps even thrive as the northern climate gets warmer. Conversely, species like the duskytail, whose genes are not as spread out, could be locally adapted to climatic conditions at the edge of the range and northern populations might reduce under climate change.

Either way, it boils down to whether the species in Vancouver would respond positively to their climate becoming more like California's. So far, the answer for both species is "no," for different reasons in each species.

"In summer conditions, the duskywing larvae grew bigger, faster, and they survived better, which suggested that they liked it warmer, but winter was another story," said Dr. Hellmann. "In the warmer winter, they increased metabolism and burned through energy faster. This suggests that they were adapted to the cooler winters of Vancouver."

As for northern swallowtails in central conditions, "They just didn't care," Dr. Hellmann said. "They didn't respond to warming at all. They didn't do better or worse. This means that assumptions about warming possibly benefiting species [with more spread out genes], particularly at the northern edge of the range, are not appropriate."


The Genetic Connection

The team has begun studying the genetic explanation for how the two species respond to warming. They are investigating what genes are responsible for the individualized responses, and will use genomic tools to learn which genes are involved when the species is experiencing climate change, said Dr. Hellmann. "We will also try to determine which genes these butterflies are synthesizing when they experience climate warming. We want to know if northern and southern members of the same species are expressing their genome differently or the same."

The answers may explain the differences between various populations of the same species -- northern vs. central -- and why some species might not be inclined to relocate as the climate heats up.

"Expecting creatures to pick up and move north makes sense theoretically," Dr. Hellmann said. "But the reality is that genetic and physiological interactions are so complicated, it's hard to imagine how it will play out for all species everywhere."

Dr. Hellmann leads the research team comprised of Shannon Pelini, Jason Dzurisin, Shawn O'Neil and Scott Emrich, all of the University of Notre Dame, Notre Dame, IN; and Caroline Williams and Brent Sinclair, of the University of Western Ontario, London, ON, CN. Dr. Hellman will discuss the team's work the conference, Global Change and Global Science: Comparative Physiology in a Changing World, being held

NASA's Great Observatories Witness a Galactic Spectacle

A new image of two tangled galaxies has been released by NASA's Great Observatories. The Antennae galaxies, located about 62 million light-years from Earth, are shown in a new composite image from the Chandra X-ray Observatory (blue), the Hubble Space Telescope (gold and brown), and the Spitzer Space Telescope (red). The Antennae galaxies take their name from the long, antenna-like arms seen in wide-angle views of the system. These features were produced in the collision.


The collision, which began more than 100 million years ago and is still occurring, has triggered the formation of millions of stars in clouds of dusts and gas in the galaxies. The most massive of these young stars have already sped through their evolution in a few million years and exploded as supernovas.

The X-ray image from Chandra shows huge clouds of hot, interstellar gas, which have been injected with rich deposits of elements from supernova explosions. This enriched gas, which includes elements such as oxygen, iron, magnesium and silicon, will be incorporated into new generations of stars and planets. The bright, point-like sources in the image are produced by material falling onto black holes and neutron stars that are remnants of the massive stars. Some of these black holes may have masses that are almost one hundred times that of the sun.

The Spitzer data show infrared light from warm dust clouds that have been heated by newborn stars, with the brightest clouds lying in the overlap region between the two galaxies. The Hubble data reveal old stars and star-forming regions in gold and white, while filaments of dust appear in brown. Many of the fainter objects in the optical image are clusters containing thousands of stars.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

Quantum Networks

 A team of Harvard physicists led by Mikhail D. Lukin has achieved the first-ever quantum entanglement of photons and solid-state materials. The work marks a key advance toward practical quantum networks, as the first experimental demonstration of a means by which solid-state quantum bits, or "qubits," can communicate with one another over long distances.



Quantum networking applications such as long-distance communication and distributed computing would require the nodes that process and store quantum data in qubits to be connected to one another by entanglement, a state where two different atoms become indelibly linked such that one inherits the properties of the other.


"In quantum computing and quantum communication, a big question has been whether or how it would be possible to actually connect qubits, separated by long distances, to one another," says Lukin, professor of physics at Harvard and co-author of a paper describing the work in the journal Nature.


"Demonstration of quantum entanglement between a solid-state material and photons is an important advance toward linking qubits together into a quantum network."


Quantum entanglement has previously been demonstrated only with photons and individual ions or atoms.


"Our work takes this one step further, showing how one can engineer and control the interaction between individual photons and matter in a solid-state material," says first author Emre Togan, a graduate student in physics at Harvard. "What's more, we show that the photons can be imprinted with the information stored in a qubit."

Quantum entanglement, famously termed "spooky action at a distance" by a skeptical Albert Einstein, is a fundamental property of quantum mechanics. It allows one to distribute quantum information over tens of thousands of kilometers, limited only by how fast and how far members of the entangled pair can propagate in space.


The new result builds upon earlier work by Lukin's group to use single atom impurities in diamonds as qubits. Lukin and colleagues have previously shown that these impurities can be controlled by focusing laser light on a diamond lattice flaw where nitrogen replaces an atom of carbon. That previous work showed that the so-called spin degrees of freedom of these impurities make excellent quantum memory.


Lukin and his co-authors now say that these impurities are also remarkable because, when excited with a sequence of finely tuned microwave and laser pulses, they can emit photons one at a time, such that photons are entangled with quantum memory. Such a stream of single photons can be used for secure transmission of information.


"Since photons are the fastest carriers of quantum information, and spin memory can robustly store quantum information for relatively long periods of time, entangled spin-photon pairs are ideal for the realization of quantum networks," Lukin says. "Such a network, a quantum analog to the conventional internet, could allow for absolutely secure communication over long distances."

Prompting hearts to make their own beating muscle

Beating heart muscle cells have for the first time been made directly from other heart cells. The breakthrough may enable damaged heart muscle to be repaired by converting the structural cells called fibroblasts into the cardiomyocytes that make the heart beat.


The route from fibroblasts to cardiomyocytes is so direct that no transitory stem cells need to be formed in the process, avoiding the extra step by which many other researchers are trying to create heart cells from patients' own cells, or from human embryonic stem cells.

"Other teams, including ours, have spent significant effort making cardiomyoctes from stem cells for regenerative purposes," says Deepak Srivastava of the Gladstone Institute of Cardiovascular Disease in San Francisco.



Change of heart

Now Srivastava and his team have created mouse cardiomyocytes by exposing mouse fibroblasts to three transcription factor proteins called Gata4, Mef2c and Tbx5 that activate genes needed for the formation of embryonic heart tissue. "The fibroblasts started to convert within a few days and continued to make the transition to cardiomyocytes over several weeks, beating at about one month," Srivastava says.

The team also transplanted treated fibroblasts into the hearts of live mice, where they developed into cardiomyocytes.

Next, Srivastava's team will see if the process works on human fibroblasts. They will also hunt for ways to morph fibroblasts without having to first infect them with a virus – which is how the transcription factors were transported to the mouse fibroblasts.



Future therapy

Srivastava suggests that people with heart damage might eventually be treated with stents that release the transcription factors to stimulate the generation of cardiomyocytes from their own fibroblasts.

"The new approach is elegantly simple, to convert the non-muscular components of the heart to cardiac muscle," says Chris Mason, professor of regenerative medicine at University College London.

Mason points out that in a similar approach reported in 2008, Doug Melton and his colleagues at Harvard University showed they could change ordinary mouse pancreas cells into the beta cells that make insulin. "The direct reprogramming strategy may be the best route forward for a number of diseases where cell replacement is impractical," says Mason.

Greenland Glacier Calves Island Four Times the Size of Manhattan

 A University of Delaware researcher reports that an "ice island" four times the size of Manhattan has calved from Greenland's Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962.

"In the early morning hours of August 5, 2010, an ice island four times the size of Manhattan was born in northern Greenland," said Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware's College of Earth, Ocean, and Environment. Muenchow's research in Nares Strait, between Greenland and Canada, is supported by the National Science Foundation (NSF).

Satellite imagery of this remote area at 81 degrees N latitude and 61 degrees W longitude, about 620 miles [1,000 km] south of the North Pole, reveals that Petermann Glacier lost about one-quarter of its 43-mile long [70 km] floating ice-shelf.

Trudy Wohlleben of the Canadian Ice Service discovered the ice island within hours after NASA's MODIS-Aqua satellite took the data on Aug. 5, at 8:40 UTC (4:40 EDT), Muenchow said. These raw data were downloaded, processed, and analyzed at the University of Delaware in near real-time as part of Muenchow's NSF research.

Petermann Glacier, the parent of the new ice island, is one of the two largest remaining glaciers in Greenland that terminate in floating shelves. The glacier connects the great Greenland ice sheet directly with the ocean.

The new ice island has an area of at least 100 square miles and a thickness up to half the height of the Empire State Building.

"The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days," Muenchow said.

The island will enter Nares Strait, a deep waterway between northern Greenland and Canada where, since 2003, a University of Delaware ocean and ice observing array has been maintained by Muenchow with collaborators in Oregon (Prof. Kelly Falkner), British Columbia (Prof. Humfrey Melling), and England (Prof. Helen Johnson).

"In Nares Strait, the ice island will encounter real islands that are all much smaller in size," Muenchow said. "The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents. From there, it will likely follow along the coasts of Baffin Island and Labrador, to reach the Atlantic within the next two years."

The last time such a massive ice island formed was in 1962 when Ward Hunt Ice Shelf calved a 230 square-mile island, smaller pieces of which became lodged between real islands inside Nares Strait. Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles). In 2005, the Ayles Ice Shelf disintegrated and became an ice island (34 square miles) about 60 miles to the west of Petermann Fjord.

latest news and articles on science: New Wall Climbing Robot

latest news and articles on science: New Wall Climbing Robot: " Wielding two claws, a motor and a tail that swings like a grandfather clock's pendulum, a small robot named ROCR ('rocker') scrambles up a ..."

New Wall Climbing Robot

 Wielding two claws, a motor and a tail that swings like a grandfather clock's pendulum, a small robot named ROCR ("rocker") scrambles up a carpeted, 8-foot wall in just over 15 seconds -- the first such robot designed to climb efficiently and move like human rock climbers or apes swinging through trees.


"While this robot eventually can be used for inspection, maintenance and surveillance, probably the greatest short-term potential is as a teaching tool or as a really cool toy," says robot developer William Provancher, an assistant professor of mechanical engineering at the University of Utah.

His study on development of the ROCR Oscillating Climbing Robot is set for online publication this month by Transactions on Mechatronics, a journal of the Institute of Electrical and Electronics Engineers and American Society of Mechanical Engineers.

Provancher and his colleagues wrote that most climbing robots "are intended for maintenance or inspection in environments such as the exteriors of buildings, bridges or dams, storage tanks, nuclear facilities or reconnaissance within buildings."

But until now, most climbing robots were designed not with efficiency in mind, only with a more basic goal: not falling off the wall they are climbing.

"While prior climbing robots have focused on issues such as speed, adhering to the wall, and deciding how and where to move, ROCR is the first to focus on climbing efficiently," Provancher says.

One previous climbing robot has ascended about four times faster than ROCR, which can climb at 6.2 inches per second, but ROCR achieved 20 percent efficiency in climbing tests, "which is relatively impressive given that a car's engine is approximately 25 percent efficient," Provancher says.

The robot's efficiency is defined as the ratio of work performed in the act of climbing to the electrical energy consumed by the robot, he says.

Provancher's development, testing and study of the self-contained robot was co-authored by Mark Fehlberg, a University of Utah doctoral student in mechanical engineering, and Samuel Jensen-Segal, a former Utah master's degree student now working as an engineer for a New Hampshire company.


The National Science Foundation and University of Utah funded the research.

ROCR is a Swinger that Claws Its Way to the Top

Other researchers have studied a variety of ways for climbing robots to stick to walls, including dry adhesives, microspines, so-called "dactyl" spines or large claws like ROCR's, suction cups, magnets, and even a mix of dry adhesive and claws to mimic wall-climbing geckos.

Now that various methods have been tried and proven for robots to climb a variety of wall surfaces, "if you are going to have a robot with versatility and mission-life, efficiency rises to the top of the list of things to focus on," Provancher says.

Nevertheless, "there's a lot more work to be done" before climbing robots are in common use, he adds.

Some previous climbing robots have been large, with two to eight legs. ROCR, in contrast, is small and lightweight: only 12.2 inches wide, 18 inches long from top to bottom and weighing only 1.2 pounds.

The motor that drives the robot's tail and a curved, girder-like stabilizer bar attach to the robot's upper body. The upper body also has two small, steel, hook-like claws to sink into a carpeted wall as the robot climbs. Without the stabilizer, ROCR's claws tended to move away from the wall as it climbed and it fell.

The motor drives a gear at the top of the tail, causing the tail to swing back and forth, which propels the robot upward. A battery is at the end of the tail and provides the mass that is necessary to swing the robot upward.

"ROCR alternatively grips the wall with one hand at a time and swings its tail, causing a center of gravity shift that raises its free hand, which then grips the climbing surface," the study says. "The hands swap gripping duties and ROCR swings its tail in the opposite direction."

ROCR is self-contained and autonomous, with a microcomputer, sensors and power electronics to execute desired tail motions to make it climb.


Provancher says that to achieve efficiency, ROCR mimics animals and machines.

"It pursues this goal of efficiency with a design that mimics efficient systems both in nature and manmade," he says. "It mimics a gibbon swinging through the trees and a grandfather clock's pendulum, both of which are extremely efficient."

The study says: "The core innovations of ROCR -- its energy-efficient climbing strategy and simple mechanical design -- arise from observing mass shifting in human climbers and brachiative [swinging] motion in animals."

Simulating and Testing a Climbing Robot

Before testing the robot itself, Provancher and colleagues used computer software to simulate ROCR's climbing, using such simulation to evaluate the most efficient climbing strategies and fine-tune the robot's physical features.

Then they conducted experiments, varying how fast and how far the robot's tail swung, to determine how to get the robot to climb most efficiently up an 8-foot-tall piece of plywood covered with a short-nap carpet.

The robot operated fastest and most efficiently when it ran near resonance -- near the robot's natural frequency -- similar to the way a grandfather clock's pendulum swings at its natural frequency. With its tail swinging more slowly, it climbed but not as quickly or efficiently.

The researchers found it achieve the greatest efficiency -- 20 percent -- when the tail swung back and forth 120 degrees (or 60 degrees to each side of straight down), when the tail swung back and forth 1.125 times per seconds and when the claws were spaced 4.9 inches apart.

When the tail swung at two times per second, it was too fast and ROCR jumped off the wall, and was caught by a safety cord so it wasn't damaged.

Provancher says the study is the first to set a benchmark for the efficiency of climbing robots against which future models may be compared. He says future work will include improving the robot's design, integrating more complex mechanisms for gripping to walls of various sorts, such as brick and sandstone, and investigating more complex ways of controlling the robot -- all aimed at improving efficiency.

"Higher climbing efficiencies will extend the battery life of a self-contained, autonomous robot and expand the variety of tasks the robot can perform," he says

Potential Cure Discovered for Degenerative Vision Diseases Leading to Terminal Blindness

 Neurobiologists funded by the Office of Naval Research (ONR) have discovered a potential cure for degenerative vision diseases leading to terminal blindness. The solution, however, may be rooted in an unconventional therapeutic approach.


Scientists at the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland, are manipulating the proteins that cause blindness in mice. The scientists have successfully restored vision in the light-sensing cells of the retina.

Dr. Thomas McKenna, program officer for ONR's Neural Computation Program, said this research has significant future implications.

"In the course of their study, these researchers discovered an approach to restore vision in blind mice with congenital macular degeneration," McKenna said. "This technology shows great promise for the partial restoration of vision for blind patients."

This initiative, supported by ONR Global's Naval International Cooperative Opportunities in Science and Technology Program (NICOP), studies retinitis pigmentosa, the incurable genetic eye disease, which causes more than 2 million worldwide cases of tunnel vision and night blindness. If left untreated, the disease can lead to complete blindness as the color-sensing cells in the retina slowly degenerate.

Dr. Clay Stewart, technical director, ONR Global, explained the importance of the NICOP program for providing a platform for innovative international basic research that could ultimately have a profound impact on naval activities.

McKenna, a recipient of the 2009 Delores M. Etter Top Scientists and Engineers of the Year award, said additional studies are needed before making the treatment available to visually challenged populations. Next, the team plans to explore the duration of therapeutic effects and whether the gene therapy could have applications for other eye diseases.

ONR's research is part of a global effort to combat visual diseases. The American Foundation for the Blind, a national nonprofit organization, reports that more than 25 million U.S. adults have some form vision loss. According to the Foundation Fighting Blindness, about 100,000 Americans suffer from retinitis pigmentosa.

another kind of the solar power

Call it the anti-sunscreen. That's more or less the description of what many solar energy researchers would like to find -- light-catching substances that could be added to photovoltaic materials in order to convert more of the sun's energy into carbon-free electricity.


Research reported in the journal Applied Physics Letters, published by the American Institute of Physics (AIP), describes how solar power could potentially be harvested by using oxide materials that contain the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, embedded selenium in zinc oxide, a relatively inexpensive material that could be promising for solar power conversion if it could make more efficient use of the sun's energy. The team found that even a relatively small amount of selenium, just 9 percent of the mostly zinc-oxide base, dramatically boosted the material's efficiency in absorbing light.

"Researchers are exploring ways to make solar cells both less expensive and more efficient; this result potentially addresses both of those needs," says author Marie Mayer, a fourth-year University of California, Berkeley doctoral student based out of LBNL's Solar Materials Energy Research Group, which is working on novel materials for sustainable clean-energy sources.


Mayer says that photoelectrochemical water splitting, using energy from the sun to cleave water into hydrogen and oxygen gases, could potentially be the most exciting future application for her work. Harnessing this reaction is key to the eventual production of zero-emission hydrogen powered vehicles, which hypothetically will run only on water and sunlight. Like most researchers, Mayer isn't predicting hydrogen cars on the roads in any meaningful numbers soon. Still, the great thing about solar power, she says, is that "if you can dream it, someone is trying to research it."

issue on climate change

The way that humanity reacts to climate change may do more damage to many areas of the planet than climate change itself unless we plan properly, an important new study published in Conservation Letters by Conservation International's Will Turner and a group of other leading scientists has concluded.


The paper Climate change: helping nature survive the human response, looks at efforts to both reduce emissions of greenhouse gases and potential action that could be taken by people to adapt to a changed climate and assesses the potential impact that these could have on global ecosystems.

In particular it notes that one fifth of the world's remaining tropical forests lie within 50km of human populations that could be inundated if sea levels rise by 1m. These forests would make attractive sources of fuel-wood, building materials, food and other key resources and would be likely to attract a population forced to migrate by rising sea levels. About half of all Alliance for Zero Extinction sites - which contain the last surviving members of certain species - are also in these zones.

Dr Turner said: "There are numerous studies looking at the impacts of climate change on biodiversity, but very little time has been taken to consider what our responses to climate change might do to the planet."

The paper notes that efforts to reduce greenhouse gas emissions by constructing dams for hydropower generation can cause substantial damage to key freshwater ecosystems as well as to the flora and fauna in the flooded valleys. It also notes that the generally bogus concept that biofuels reduce carbon emissions is still being used as a justification for the felling of large swathes of biodiverse tropical forests.

The report also reviews studies examining the complex series of outcomes in historical examples of climate change and environmental degradation, and humanity's efforts to adapt to changing circumstances. Migration caused in part by climatic instability in Burkina Faso in the late 20th century, for example, led to a 13 per cent decline in forest cover as areas were cleared for agriculture, and a decline in fish supplies in Ghana may have led to a significant increase in bushmeat hunting.

Dr Turner added: "If we don't take a look at the whole picture, but instead choose to look only at small parts of it we stand to make poor decisions about how to respond that could do more damage than climate change itself to the planet's biodiversity and the ecosystem services that help to keep us all alive.

"While the Tsunami in 2004 was not a climate event, many of the responses that it stimulated are comparable with how people will react to extreme weather events - and the damage that the response to the Tsunami did to many of Aceh province's important ecosystems as a result of extraction of timber and other building materials, and poor choices of locations for building , should be a lesson to us all."

Although the challenge of sustaining biodiversity in the face of climate change seems daunting, the paper notes that we must - and can - rise to the challenge.

Turner adds: "Climate change mitigation and adaptation are essential. We have to ensure that these responses do not compromise the biodiversity and ecosystem services upon which societies ultimately depend. We have to reduce emissions, we have to ensure the stability of food supplies jeopardized by climate change, we have to help people survive severe weather events - but we must plan these things so that we don't destroy life-sustaining forests, wetlands, and oceans in the process.'

The paper concludes that there are many ways of ensuring that the human response to climate change delivers the best possible outcomes for both society and the environments, and notes that in particular, maintaining and restoring natural habitats are among the cheapest, safest, and easiest solutions at our disposal to reduce greenhouse-gas emissions and help people adapt to unavoidable changes.

Dr Turner said: "Providing a positive environmental outcome is often the best way to ensure the best outcome for people. If we are sensible, we can help people and nature together cope with climate change, if we are not it will cause suffering for people and serious problems for the environment."

FACTS ON TOYOTA COMPANY

Toyota Motor said Friday that its hybrid vehicle sales in Japan had topped the one million mark and worldwide it had sold 2.68 million of the vehicles by the end of July.



Toyota Motor said Friday that its hybrid vehicle sales in Japan had topped the one million mark and worldwide it had sold 2.68 million of the vehicles by the end of July.

Toyota, the front-runner in hybrid cars that use two power sources -- a gasoline engine and another source such as an electric motor -- launched the Prius, the world's first mass-produced hybrid car, in 1997.


The world's biggest automaker later expanded use of its hybrid system to mini-vans, SUVs and rear-wheel-drive sedans.


Currently, nine Toyota-produced hybrid passenger vehicle models and three hybrid commercial vehicle models are sold in Japan and a total of eight passenger hybrid models overseas.


Sales of hybrids have been brisk in recent years because of high gasoline prices and increasing public awareness of global warming.


Last year, Toyota recalled 437,000 Prius and other hybrid vehicles to repair a flaw in the braking system, as part of around 10 million recalls worldwide that have tarnished its previously stellar reputation for quality.


However the Prius has retained the top spot in sales in Japan for the past year, according to the Japan Automobile Dealers Association.

artificial bee eye and lens

Despite their tiny brains, bees have remarkable navigation capabilities based on their vision. Now scientists have recreated a light-weight imaging system mimicking a honeybee's field of view, which could change the way we build mobile robots and small flying vehicles.

                                                          

                                           

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New research published Aug. 6 in IOP Publishing's Bioinspiration & Biomimetics, describes how the researchers from the Center of Excellence 'Cognitive Interaction Technology' at Bielefeld University, Germany, have built an artificial bee eye, complete with fully functional camera, to shed light on the insects' complex sensing, processing and navigational skills.

Consisting of a light-weight mirror-lens combination attached to a USB video camera, the artificial eye manages to achieve a field of vision comparable to that of a bee. In combining a curved reflective surface that is built into acrylic glass with lenses covering the frontal field, the bee eye camera has allowed the researchers to take unique images showing the world from an insect's viewpoint.



In the future, the researchers hope to include UV to fully reflect a bee's colour vision, which is important to honeybees for flower recognition and discrimination and also polarisation vision, which bees use for orientation. They also hope to incorporate models of the subsequent neural processing stages.

As the researchers write, "Despite the discussed limitations of our model of the spatial resolution of the honeybees compound eyes, we are confident that it is useful for many purposes, e.g. for the simulation of bee-like agents in virtual environments and, in combination with presented imaging system, for testing bee-inspired visual navigation strategies on mobile robots."

New Solar Energy Conversion Process Could Double Solar Efficiency of Solar Cells

A new process that simultaneously combines the light and heat of solar radiation to generate electricity could offer more than double the efficiency of existing solar cell technology, say the Stanford engineers who discovered it and proved that it works. The process, called "photon enhanced thermionic emission," or PETE, could reduce the costs of solar energy production enough for it to compete with oil as an energy source.



Stanford engineers have figured out how to simultaneously use the light and heat of the sun to generate electricity in a way that could make solar power production more than twice as efficient as existing methods and potentially cheap enough to compete with oil.




 


Unlike photovoltaic technology currently used in solar panels -- which becomes less efficient as the temperature rises -- the new process excels at higher temperatures.



Called "photon enhanced thermionic emission," or PETE, the process promises to surpass the efficiency of existing photovoltaic and thermal conversion technologies.



"This is really a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak," said Nick Melosh, an assistant professor of materials science and engineering, who led the research group. "It is actually something fundamentally different about how you can harvest energy."



And the materials needed to build a device to make the process work are cheap and easily available, meaning the power that comes from it will be affordable.



Melosh is senior author of a paper describing the tests the researchers conducted. It was published this week in Nature Materials.



"Just demonstrating that the process worked was a big deal," Melosh said. "And we showed this physical mechanism does exist, it works as advertised."



Most photovoltaic cells, such as those used in rooftop solar panels, use the semiconducting material silicon to convert the energy from photons of light to electricity. But the cells can only use a portion of the light spectrum, with the rest just generating heat.



This heat from unused sunlight and inefficiencies in the cells themselves account for a loss of more than 50 percent of the initial solar energy reaching the cell.



If this wasted heat energy could somehow be harvested, solar cells could be much more efficient. The problem has been that high temperatures are necessary to power heat-based conversion systems, yet solar cell efficiency rapidly decreases at higher temperatures.



Until now, no one had come up with a way to wed thermal and solar cell conversion technologies.



Melosh's group figured out that by coating a piece of semiconducting material with a thin layer of the metal cesium, it made the material able to use both light and heat to generate electricity.



"What we've demonstrated is a new physical process that is not based on standard photovoltaic mechanisms, but can give you a photovoltaic-like response at very high temperatures," Melosh said. "In fact, it works better at higher temperatures. The higher the better."



While most silicon solar cells have been rendered inert by the time the temperature reaches 100 degrees Celsius, the PETE device doesn't hit peak efficiency until it is well over 200 degrees C.



Because PETE performs best at temperatures well in excess of what a rooftop solar panel would reach, the devices will work best in solar concentrators such as parabolic dishes, which can get as hot as 800 degrees C. Dishes are used in large solar farms similar to those proposed for the Mojave Desert in Southern California and usually include a thermal conversion mechanism as part of their design, which offers another opportunity for PETE to help generate electricity, as well as minimizing costs by meshing with existing technology.



"The light would come in and hit our PETE device first, where we would take advantage of both the incident light and the heat that it produces, and then we would dump the waste heat to their existing thermal conversion systems," Melosh said. "So the PETE process has two really big benefits in energy production over normal technology."



Photovoltaic systems never get hot enough for their waste heat to be useful in thermal energy conversion, but the high temperatures at which PETE performs are perfect for generating usable high temperature waste heat. Melosh calculates the PETE process can get to 50 percent efficiency or more under solar concentration, but if combined with a thermal conversion cycle, could reach 55 or even 60 percent -- almost triple the efficiency of existing systems.



The team would like to design the devices so they could be easily bolted on to existing systems, making conversion relatively inexpensive.



The researchers used a gallium nitride semiconductor in the "proof of concept" tests. The efficiency they achieved in their testing was well below what they have calculated PETE's potential efficiency to be, which they had anticipated. But they used gallium nitride because it was the only material that had shown indications of being able to withstand the high temperature range they were interested in and still have the PETE process occur.



With the right material -- most likely a semiconductor such as gallium arsenide, which is used in a host of common household electronics -- the actual efficiency of the process could reach up to the 50 or 60 percent the researchers have calculated. They are already exploring other materials that might work.



Another advantage of the PETE system is that by using it in solar concentrators, the amount of semiconductor material needed for a device is quite small.



"For each device, we are figuring something like a six-inch wafer of actual material is all that is needed," Melosh said. "So the material cost in this is not really an issue for us, unlike the way it is for large solar panels of silicon."



The cost of materials has been one of the limiting factors in the development of the solar power industry, so reducing the amount of investment capital needed to build a solar farm is a big advance.



"The PETE process could really give the feasibility of solar power a big boost," Melosh said. "Even if we don't achieve perfect efficiency, let's say we give a 10 percent boost to the efficiency of solar conversion, going from 20 percent efficiency to 30 percent, that is still a 50 percent increase overall."



And that is still a big enough increase that it could make solar energy competitive with oil.



The research was largely funded by the Global Climate and Energy Project at Stanford and the Stanford Institute for Materials Energy Systems, which is a joint venture of Stanford and SLAC National Accelerator Laboratory, with additional support from the Department of Energy and DARPA.


A small PETE device made with cesium-coated gallium nitride glows while being tested inside an ultra-high vacuum chamber. The tests proved that the process simultaneously converted light and heat energy into electrical current.
SEE THE PICTURE OF THE DEVICE BELOW:

Research Breakthrough on the Question of Life Expectancy

                                           simple fact on biology

  Why do we grow old and what can we do to stop it? This is the question asked by many, but it appears that we are now closer to an answer thanks to new research published by Monash University researcher Dr Damian Dowling.



According to the research published in the August edition of the journal, The American Naturalist, a small set of genes in mitochondria (a membrane-enclosed organelle found in most eukaryotic cells), passed only from mothers to offspring, plays a more dynamic role in predicting life expectancies than ever previously anticipated.



The research discovered that particular mitochondrial haplotypes were linked to the life expectancies of females in the beetle species Callosobruchus maculatus.



"What we found in these beetles that some combinations of mitochondrial and nuclear genomes confer long life in virgin females, but these are not the same combinations that result in long life in females that mate once, or in females that mate many times," Dr Dowling said.



"Clearly, the genetic determinants underlying life expectancies are complex.



"As we unravel this complexity, we draw closer to the day in which we might use the genetic information encoded in the mitochondria to assist in the development of therapies that slow the onset of ageing in humans," Dr Dowling said.



In animals, most of the genetic material that controls bodily functions is found inside the cell nucleus. This is the nuclear genome -- it is passed on from generation to generation through both mothers and fathers, and it encodes somewhere between 14 thousand and 40 thousand proteins.



However, a separate genome exists that is found only within the energy-producing factories of our cells -- the mitochondria. To put things in perspective, the mitochondrial genome is tiny, encoding just 13 proteins. Despite being so small, it can pack a punch when it comes to its ability to affect a range of fundamental biological processes.



Dr Dowling, a research fellow at Monash University's School of Biological Sciences led the research together with Goran Arnqvist of Uppsala University Sweden and their student, Tejashwari Meerupati, made the discovery.



"Our findings are part of a much broader research agenda in which we are elucidating the ways in which mitochondrial genomes have shaped our evolutionary past and present. What we are finding is that natural variation in this diminutive genome results in a huge range of effects on metabolism, mating behaviour and reproductive biology, including male fertility," Dr Dowling said.



"At the outset of our research program, we suspected that the evolutionary significance of the mitochondria had probably been underestimated by scientists that have come before us, but even we have been continually surprised by the magnitude and ubiquity of the effects that we have uncovered.



"We suspect that this genome still harbours many more secrets awaiting discovery," Dr Dowling said.

                                

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