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Sunday, March 18, 2012

Popular Science articles about Paleontology And Archaeology

Mystery human fossils put spotlight on China
Fossils from two caves in south-west China have revealed a previously unknown Stone Age people and give a rare glimpse of a recent stage of human evolution with startling implications for the early peopling of Asia. The fossils are of a people with a highly unusual mix of archaic and modern anatomical features and are the youngest of their kind ever found in mainland East Asia.

Dated to just 14,500 to 11,500 years old, these people would have shared the landscape with modern-looking people at a time when China's earliest farming cultures were beginning, says an international team of scientists led by Associate Professor Darren Curnoe, of the University of New South Wales, and Professor Ji Xueping of the Yunnan Institute of Cultural Relics and Archeology.

Details of the discovery are published in the journal PLoS ONE. The team has been cautious about classifying the fossils because of their unusual mosaic of features.

"These new fossils might be of a previously unknown species, one that survived until the very end of the Ice Age around 11,000 years ago," says Professor Curnoe.

"Alternatively, they might represent a very early and previously unknown migration of modern humans out of Africa, a population who may not have contributed genetically to living people."

The remains of at least three individuals were found by Chinese archaeologists at Maludong (or Red Deer Cave), near the city of Mengzi in Yunnan Province during 1989. They remained unstudied until research began in 2008, involving scientists from six Chinese and five Australian institutions.

A Chinese geologist found a fourth partial skeleton in 1979 in a cave near the village of Longlin, in neighbouring Guangxi Zhuang Autonomous Region. It stayed encased in a block of rock until 2009 when the international team removed and reconstructed the fossils.

The skulls and teeth from Maludong and Longlin are very similar to each other and show an unusual mixture of archaic and modern anatomical features, as well as some previously unseen characters.

While Asia today contains more than half of the world's population, scientists still know little about how modern humans evolved there after our ancestors settled Eurasia some 70,000 years ago, notes Professor Curnoe.

The scientists are calling them the "Red-deer Cave people" because they hunted extinct red deer and cooked them in the cave at Maludong.

The Asian landmass is vast and scientific attention on human origins has focussed largely on Europe and Africa: research efforts have been hampered by a lack of fossils in Asia and a poor understanding of the age of those already found.

Until now, no fossils younger than 100,000 years old have been found in mainland East Asia resembling any species other than our own (Homo sapiens). This indicated the region had been empty of our evolutionary cousins when the first modern humans appeared. The new discovery suggests this might not have been the case after all and throws the spotlight once more on Asia.

"Because of the geographical diversity caused by the Qinghai-Tibet plateau, south-west China is well known as a biodiversity hotspot and for its great cultural diversity. That diversity extends well back in time" says Professor Ji.

In the last decade, Asia has produced the 17,000-year-old and highly enigmatic Indonesian Homo floresiensis ("The Hobbit") and evidence for modern human interbreeding with the ancient Denisovans from Siberia.

"The discovery of the red-deer people opens the next chapter in the human evolutionary story -- the Asian chapter -- and it's a story that's just beginning to be told," says Professor Curnoe.

Study suggests link between H. pylori bacteria and blood sugar control in adult Type 2 diabetes

A new study by researchers at NYU Langone Medical Center reveals that the presence of Helicobacter pylori (H. pylori) bacteria is associated with elevated levels of glycosylated hemoglobin (HbA1c), an important biomarker for blood glucose levels and diabetes. The association was even stronger in obese individuals with a higher Body Mass Index (BMI). The results, which suggest the bacteria may play a role in the development of diabetes in adults, are available online in The Journal of Infectious Diseases.

There have been several studies evaluating the effect of the presence of H. pylori on diabetes outcomes, but this is the first to examine the effect on HbA1c, an important, objective biomarker for long-term blood sugar levels, explained Yu Chen, PhD, MPH, associate professor of epidemiology at NYU School of Medicine, part of NYU Langone Medical Center.

"The prevalence of obesity and diabetes is growing at a rapid rate, so the more we know about what factors impact these conditions, the better chance we have for doing something about it," Dr. Chen said. Looking at the effects of H. pylori on HbA1c, and whether the association differs according to BMI status, provided what could be a key piece of information for future treatment of diabetes, she explained.

Type II diabetes causes an estimated 3.8 million adult deaths globally. There have been conflicting reports about the association between H. pylori infection and type II diabetes. To better understand the relationship between H. pylori and the disease, Dr. Chen and Martin J. Blaser, MD, the Frederick H. King Professor of Internal Medicine and professor of microbiology, analyzed data from participants in two National Health and Nutrition Surveys (NHANES III and NHANES 1999-2000) to assess the association between H. pylori and levels of HbA1c.

"Obesity is an established risk factor for diabetes and it is known that high BMI is associated with elevated HbA1c. Separately, the presence of H. pylori is also associated with elevated HbA1c," said Dr. Blaser, who has studied the bacteria for more than 20 years. "We hypothesized that having both high BMI and the presence of H. pylori would have a synergistic effect, increasing HbA1c even more than the sum of the individual effect of either risk factor alone. We now know that this is true."

H. pylori lives in the mucous layer lining the stomach where it persists for decades. It is acquired usually before the age of 10, and is transmitted mainly in families. Dr. Blaser's previous studies have confirmed the bacterium's link to stomach cancer and elucidated genes associated with its virulence, particularly a gene called cagA.

Regarding H. pylori's association with elevated HbA1c, Drs. Chen and Blaser believe the bacterium may affect the levels of two stomach hormones that help regulate blood glucose, and they suggest that eradicating H. pylori using antibiotics in some older obese individuals could be beneficial.

More research will be needed to evaluate the health effects of H. pylori and its eradication among different age groups and in relation to obesity status, the authors noted.

"If future studies confirm our finding, it may be beneficial for individuals at risk for diabetes to be tested for the presence of H. pylori and, depending on the individual's risk factor profile" Dr. Chen.

In an accompanying editorial in The Journal of Infectious Diseases, Dani Cohen, PhD, of Tel Aviv University in Israel, pointed out that while previous studies have addressed the association between type II diabetes and H. pylori in small samples, this study analyzed two independent large national samples of the general population. Dr. Cohen agreed with the study authors, suggesting that adults infected with H. pylori with higher BMI levels, even if asymptomatic, may need anti-H. pylori therapy to control or prevent type II diabetes. If the study findings are confirmed, Dr. Cohen wrote, they "could have important clinical and public health implications."

Popular Science articles about Earth and Climate

Past in monsoon changes linked to major shifts in Indian civilizations
A fundamental shift in the Indian monsoon has occurred over the last few millennia, from a steady humid monsoon that favored lush vegetation to extended periods of drought, reports a new study led by researchers at the Woods Hole Oceanographic Institution (WHOI). The study has implications for our understanding of the monsoon’s response to climate change. The Indian peninsula sustains over a billion people, yet it lies at the same latitude as the Sahara Desert. Without a monsoon, most of India would be dry and uninhabitable. The ability to predict the timing and amount of the next year’s monsoon is vital, yet even our knowledge of the monsoon’s past variability remains incomplete.

One key to this understanding lies in the core monsoon zone (CMZ) – a region in the central part of India that is a very sensitive indicator of the monsoon throughout the India peninsula.

“If you know what’s happening there, you know more or less what’s happening in the rest of India,” said Camilo Ponton, a student in the MIT-WHOI Joint Program in Oceanography and lead author of the study recently published in Geophysical Research Letters entitled "Holocene Aridification of India". “Our biggest problem has been a lack of evidence from this region to extend the short, existing records.”

The study was designed by WHOI geologist Liviu Giosan and geochemist Tim Eglinton, now at ETH in Zurich, and makes use of a sediment core collected by the National Gas Hydrate Program of India in 2006. Sailing around India aboard the drilling vessel JOIDES Resolution for several months, Giosan enlisted colleagues from India and US to help with the project. Extracted from a “sweet spot” in the Bay of Bengal where the Godavari River drains the central Indian peninsula and over which monsoon winds carry most of the precipitation, the core has provided the basis for a 10,000-year reconstruction of climate in the Indian peninsula’s CMZ .

“We are fortunate to have this core from close to the river mouth, where it accumulates sediment very fast,” said Ponton. “Every centimeter of sediment contains 10 to 20 years’ worth of information. So it gives us the advantage of high temporal resolution to address the problems.”

When put together, the research tells the story of growing aridity in India, enables valuable insights into the impact of the monsoon on past cultures, and points scientists toward a way to model future monsoons.

To assemble the 10,000-year record, the team looked to both what the land and the ocean could tell them. Contained within the sediment core’s layers are microscopic compounds from the trees, grasses, and shrubs that lived in the region and remnants of plankton fossils from the ocean.

“The geochemical analyses of the leaf waxes tell a simple story,” said Giosan. “About 10,000 years ago to about 4500 ago, the Godavari River drained mostly terrain that had humidity-loving plants. Stepwise changes starting at around 4,000 years ago and again after 1,700 years ago changed the flora toward aridity-adapted plants. That tells us that central India – the core monsoon zone – became drier.”

Analyses of the plankton fossils support the story reconstructed from plant remains and reveal a record of unprecedented spikes and troughs in the Bay of Bengal’s salinity – becoming saltier during drought periods and fresher when water from the monsoon filled the river and rained into the Bay. Similar drought periods have been documented in shorter records from tree rings and cave stalagmites within India lending further support to this interpretation.

With a picture emerging of changes in the ancient flora of India, Giosan tapped archaeobotanist Dorian Fuller’s interest.

“What the new paleo-climatic information makes clear is that the shift towards more arid conditions around 4,000 years ago corresponds to the time when agricultural populations expanded and settled village life began,” says Fuller of the Institute of Archaeology, University College London. “Arid-adapted food production is an old cultural tradition in the region, with cultivation of drought-tolerant millets and soil-restoring bean species. There may be lessons to learn here, as these drought-tolerant agricultural traditions have eroded over the past century, with shift towards more water and chemical intensive forms of modern agriculture.”

Together, the geological record and the archaeological evidence tell a story of the possible fate of India’s earliest civilizations. Cultural changes occurred across the Indian subcontinent as the climate became more arid after ~4,000 years. In the already dry Indus basin, the urban Harappan civilization failed to adapt to even harsher conditions and slowly collapsed. But aridity favored an increase in sophistication in the central and south India where tropical forest decreased in extent and people began to settle and do more agriculture. Human resourcefulness proved again crucial in the rapid proliferation of rain-collecting water tanks across the Indian peninsula, just as the long series of droughts settled in over the last 1,700 years.

What can this record tell us about future Indian monsoons? According to Ponton, “How the monsoon will behave in the future is highly controversial. Our research provides clues for modeling and that could help determine whether the monsoon will increase or decrease with global warming.”

The study found that the type of monsoon and its droughts are a function of the Northern Hemisphere’s incoming solar radiation – or “insolation.” Every year, the band of heavy rain known as the Inter-Tropical Convergence Zone, or ITCZ, moves north over India.

“We found that when the Asian continent is least heated by the sun, the northward movement of the rain appears to hesitate between the Equator and Asia, bringing less rain to the north,” said Giosan. “The fact that long droughts have not occurred over the last 100 years or so, as humans started to heat up the planet, but did occur earlier, suggest that we changed the entire monsoon game, and may have inadvertently made it more stable!”

Popular Science articles about Astronomy & Space

A half-billion stars and galaxies from NASA's WISE mission revealed -- many for first time
NASA unveiled a new atlas and catalog of the entire infrared sky today showing more than a half billion stars, galaxies and other objects captured by the Wide-field Infrared Survey Explorer (WISE) mission. "Today, WISE delivers the fruit of 14 years of effort to the astronomical community," said Edward Wright, WISE principal investigator at UCLA, who first began working on the mission with other team members in 1998.

WISE launched Dec. 14, 2009, and mapped the entire sky in 2010 with vastly better sensitivity than its predecessors. It collected more than 2.7 million images taken at four infrared wavelengths of light, capturing everything from nearby asteroids to distant galaxies. Since then, the team has been processing more than 15 trillion bytes of returned data. A preliminary release of WISE data, covering the first half of the sky surveyed, was made last April.

The WISE catalog of the entire sky meets the mission's fundamental objective. The individual WISE exposures have been combined into an atlas of more than 18,000 images covering the sky and a catalog listing the infrared properties of more than 560 million individual objects found in the images. Most of the objects are stars and galaxies, with roughly equal numbers of each. Many of them have never been seen before.

WISE observations have led to numerous discoveries, including the elusive, coolest class of stars. Astronomers hunted for these failed stars, called "Y-dwarfs," for more than a decade. Because they have been cooling since their formation, they don't shine in visible light and could not be spotted until WISE mapped the sky with its infrared vision.

WISE also took a poll of near-Earth asteroids, finding there are significantly fewer mid-size objects than previously thought. It also determined NASA has found more than 90 percent of the largest near-Earth asteroids.

Other discoveries were unexpected. WISE found the first known "Trojan" asteroid to share the same orbital path around the sun as Earth. One of the images released today shows a surprising view of an "echo" of infrared light surrounding an exploded star. The echo was etched in the clouds of gas and dust when the flash of light from the supernova explosion heated surrounding clouds. At least 100 papers on the results from the WISE survey already have been published. More discoveries are expected now that astronomers have access to the whole sky as seen by the spacecraft.

"With the release of the all-sky catalog and atlas, WISE joins the pantheon of great sky surveys that have led to many remarkable discoveries about the universe," said Roc Cutri, who leads the WISE data processing and archiving effort at the Infrared and Processing Analysis Center at the California Institute of Technology in Pasadena. "It will be exciting and rewarding to see the innovative ways the science and educational communities will use WISE in their studies now that they have the data at their fingertips."

NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., manages and operates WISE for NASA's Science Mission Directorate in Washington. The mission was competitively selected under NASA's Explorers Program, which is managed by NASA's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah, and the spacecraft was built by Ball Aerospace and Technologies Corp., in Boulder, Colo. Science operations, data processing and archiving take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

Giant squids' giant eyes: The better to see hungry whales with

It's no surprise that giant and colossal squid are big, but it's their eyes that are the real standouts when it comes to size, with diameters measuring two or three times that of any other animal. Now, researchers reporting online on March 15 in Current Biology, a Cell Press publication, have used complex computations to explain those massive peepers. Giant squids' 10-inch eyes allow them to see very large and hungry sperm whales from a distance in the pitch darkness of their deep-sea home. According to the researchers' calculations, animals living underwater would have no use for such large eyes if the goal were to see an average object, such as prey smaller than themselves. That's why even the eyes of large whales aren't much more than 3.5 inches across.

"For seeing in dim light, a large eye is better than a small eye, simply because it picks up more light," said Dan-Eric Nilsson of Lund University. "But for animals that live in the sea or in lakes, the optical properties of water will severely restrict how far away things can be seen.

"Through complex computations we have found that for animals living in water, it does not pay to make eyes much bigger than an orange. Making eyes larger than that will only marginally improve vision, but eyes are expensive to build and maintain."

For Nilsson's team, that begged the question of why giant squid bother with their giant eyes. Using a mathematical model of underwater vision, they tested the benefits of very large eyes for a broad range of tasks under various light conditions. Those efforts showed that very large eyes aren't much better than smaller ones unless one wants to see something that is itself very big, like a whale.

Giant squid may also be unique in that they are powerful enough to escape a sperm whale once they've spotted one, Nilsson says. But how can giant squid see a sperm whale at depths beyond daylight's reach?

"The answer is bioluminescence -- light produced by small gelatinous animals when they are disturbed by the whale moving through the water," Nilsson says. "It is well known that bioluminescence can reveal submarines at night, and diving sperm whales will become visible for the same reason."

The findings may also explain the large eyes of prehistoric ichthyosaurs, giant marine reptiles that looked something like dolphins, the researchers say. Although ichthyosaurs lived long before whales came along, they would have had to contend with giant predatory pliosaurs.

Teenagers scoop science awards

A trio of Britain's brightest youngsters have scooped top honours in science and engineering at the 2012 National Science & Engineering Competition.

Two Cardiff teenagers were voted Young Engineers of the Year for creating a portable device to monitor when mothers are about to go into labour. A third teenager from West Kirby carried off the title of UK Young Scientist of the Year for pioneering work to target specific cancer cells.

The trio, all aged 17, were chosen from a line up of among 360 talented youngsters all with potentially world-beating ideas.

They were singled out by a panel of world-class judges which included Dr Maggie Aderin-Pocock, Nobel Prize-winning biochemist Sir Tim Hunt, and the Science Museum's inventor in residence Mark Champkins.

Wasim Miah and Jessica Jones, from St David's College, Cardiff, South Wales, were named Young Engineers of the Year. The pair impressed with a mechanical and electrical device called the Contraction Optical Monitoring System, which measures foetal contraction intensity. It provides mothers-to-be with a simple indication of when they are about to go into labour, avoiding the traditional mad dash to hospital.

"This is such a massive honour. It feels so strange and I can't believe that we've actually won," a jubilant Jessica said. "The competition was so fierce. I can't believe I'm the first girl to win the UK Young Engineer of the Year, it makes the achievement all the more amazing."

Co-winner Wasim added: "This is absolutely brilliant but we're both still shell shocked. We didn't even tell anyone that we'd entered the competition because we didn't think we would be nominated. We thought we would get some useful contacts to help develop the project so to win is an amazing bonus."

Kirtana Vallabhaneni said she was overwhelmed at being crowned UK Young Scientist of the Year. She has been involved in groundbreaking work helping to identify the harmful cells that cause pancreatic cancer. The aim of the project is to isolate cells in the pancreas that can be targeted with chemotherapy rather than subjecting the whole body to the treatment.

"Everything that I've worked for over the last year has come together. I'm so happy," she said.

The finals took place at The Big Bang UK Young Scientists & Engineers Fair, the country's largest celebration of science and engineering for young people, at The NEC, Birmingham, and prizes were awarded by Minister for Universities and Science David Willetts.

Thursday, March 15, 2012

Google plans major revamp for search engine

The Web giant has been working on the "next generation of search" over the last couple of years and now it's ready to start rolling it out.
Google is about to embark on its biggest renovation in history. In order to keep up with increased competition and new technology, the Web giant is working to keep ahead of the pack by completely revamping its search function, according to The Wall Street Journal.

Google search executive Amit Singhal told The Wall Street Journal that the new Google search will look more like "how humans understand the world."

Changes are expected to roll out over the next few months, the Journal reports, but the full makeover to "next generation of search" will likely take years. A Google spokesperson told CNET that there is not a specific timeline and the company's philosophy is to launch things when they're ready.

The plan for the revamp isn't necessarily to swap out the current keyword-search system but rather to provide more relevant results. This process will work by using technology called "semantic search." With semantic searches, people's searches will be better matched with "entities"--or people, places and things--which the company has been building over the past two years, reports the Journal.

For example, the Journal reports that people who search for "Lake Tahoe" today get links to the lake's visitor bureau website and a map; whereas with the makeover, they will see key "attributes" about the lake, including location, altitude, average temperature and salt content.

ntel's journey in to cloud computing

With increasing number of headcounts and ever growing demand for IT and computing resources, Intel had no other choice but to consolidate its internal IT requirements that would help addressing annual IT budgets as well as overall operational costs.

It was back in 2009 that Intel took a very significant step of moving towards cloud computing and reap its benefits in coming years. “In 2009, we started to work on cloud strategy and initiated the use of public cloud for non-core business needs such as e-mail applications through software-as-a-service model,” said Kimberly S Stevenson, Intel Corporation's vice president - IT and general manager - IT Global Operations and Services.

While, Intel used public cloud for non-core business needs, it framed an internal cloud strategy, also know as private cloud. Under the acronym DOMES (Design, Office, Manufacturing, Enterprise, Services), which stands for various organizational departments and functions, Intel slowly started to deploy virtualization within these units.

During the first year, Intel virtualized around 12 per cent environment within the organization with the focus on federated clouds. By 2011, the company virtualized over 62 per cent of its environment that led to semi-automated server provisioning and resource allocations based the on-demand self servicing model.

“Our aim is 75 per cent virtualization by 2012, which will allow fully automated server provisioning and resource allocations along with 80 per cent effective asset utilization rate with zero business impact,” Stevenson opined.

Though working on federated cloud throws key challenges such as security and business model, Stevenson stressed on the business benefits it offered to Intel. “It helped in improving the velocity and availability of IT services, provisioning servers in short time, flexible configurations, secured infrastructure and saving cost to the business.”

Intel claimed that it saved net $9 million through internal cloud efforts. According to Stevenson, during 2008, Intel allocated about 3.8 per cent of its total revenues on IT spends. However, due to the cloud strategy they were able to bring it down to 2.5- 3 per cent in recent years.

Intel's internal cloud profile include over 40 per cent for production work load, 22 per cent for human resource, finance and legal, 13 per cent for enterprise resource planning, five per cent for engineering and 19 per cent for sales and marketing.

For Stevenson, the cloud journey was a tough one as she and her team had to make business case of the proposed cloud strategy, present it to the board and get it approved. However, moving forward to future she said, “We learned many things on our cloud journey – right from cloud technology, leadership support, IT business partnership to short term priorities.”

Thursday, March 1, 2012

Alta Devices: Finding a Solar Solution

Looking to enter a highly ­competitive solar market, Alta Devices hopes to use a combination of technological advances and manufacturing savvy to succeed where many others have crashed and burned.

Alta Devices is a small but well-funded startup located in the same nondescript Silicon Valley office building that once served as the headquarters for Solyndra, the infamous solar company that went bankrupt last year after burning through hundreds of millions of dollars in public and venture investments. Whether the location has bad karma is still not clear, jokes Alta's CEO, Christopher Norris. But Norris, a former semiconductor-industry executive and venture capitalist, does know that the fate of his company will hinge on its ability to navigate the risky and expensive process of scaling up its novel technology, which he believes could produce power at a price competitive with fossil-fuel plants and far more cheaply than today's solar modules.
On a table in Alta's conference room, Norris lays out samples of the company's solar cells, flexible black patches encapsulated in clear plastic. They look unremarkable, but that's because the key ingredient is all but invisible: microscopically thin sheets of gallium arsenide. The semiconductor is so good at absorbing sunlight and turning it into electricity that one of Alta's devices, containing an active layer of gallium arsenide only a couple of micrometers thick, recently set a record for photovoltaic efficiency. But gallium arsenide is also extremely expensive to use in solar cells, and thin films of it tend to be fragile and difficult to fabricate. In fact, Alta's innovations lie not in choosing the material—the semiconductor has been used in solar cells on satellites and spacecraft for decades—but in figuring out how to turn it into solar modules cheap enough to be practical for most applications.
The company, which was founded in 2007, is based on the work of two of the world's leading academic researchers in photonic materials. One of them, Eli Yablonovitch, now a professor of electrical engineering at the University of California, Berkeley, developed and patented a technique for creating ultrathin films of gallium arsenide in the 1980s, when he worked at Bell Communications Research. The other, Harry Atwater, a professor of applied physics and materials science at Caltech, is a pioneer in the use of microstructures and nanostructures to improve materials' ability to trap light and convert it into electricity. Andy ­Rappaport, a venture capitalist at August Capital, teamed up with the two scientists to found Alta, recruiting fellow Silicon Valley veteran Bill Joy as an investor and, with the other cofounders, building a management team that included Norris. The goal: to make highly efficient solar cells, and to make them more cheaply than those based on existing silicon technology.
It is at this point that many solar startups have gone wrong, rushing to scale up an innovative technology before understanding its economics and engineering challenges. Instead, Alta spent its first several years in stealth mode, quietly attempting to figure out, as Norris puts it, whether its process for making gallium arsenide solar cells was more than a "science experiment" and could serve as a viable basis for manufacturing.
Flexible power: Alta’s solar cells can be made into bendable sheets. In this sample, a series of solar cells are encapsulated in a roofing material. Credit: Gabriela Hasbun
Remnants of the science experiment are still visible in the modest lab at the back of Alta's offices. Small ceramic pots sit on electric hot plates—relics of the company's early efforts to optimize ­Yablonovitch's technique of "epitaxial liftoff," which uses acids to precisely separate thin films of gallium arsenide from the wafers on which they are grown. Elsewhere in the lab the equipment gets progressively larger and more sophisticated, reflecting the scaling up of the process. Near a viewing window that allows potential investors to peer into the lab without donning clean-room coverings is one of the jewels of the company's development efforts: a long piece of equipment in which batches of samples are processed to create the thin-film solar cells. It's convincing evidence that the early work with pots and hot plates can be transformed into an automated process capable of the yields necessary for real-world manufacturing.
SOLAR LIFTOFF
When Bill Joy, a cofounder of Sun Microsystems and now a leading Silicon Valley venture capitalist, first saw the business plan for what became Alta Devices, he and his colleagues at Kleiner Perkins Caufield & Byers were already looking for high-efficiency thin-film solar technology. Joy keeps a running list—currently about 12 to 15 items long—of desirable technologies that he believes he has "a reasonable chance of finding." Solar cells that are highly efficient in converting sunlight and that can be made cheaply in flexible sheets could provide ways to dramatically lower the overall costs of solar power. Gallium arsenide technology was a natural choice for efficiency, but Alta's economics were what really interested the investors. "Their core competency was how to make it manufacturable," says Joy, who joined Rappaport as an investor within a few months.
Gallium arsenide is a nearly ideal solar material, for a number of reasons. Not only does it absorb far more sunlight than silicon—thin films of it capture as many photons as silicon 100 times thicker—but it's less sensitive to heat than silicon solar cells, whose performance dramatically declines above 25 °C. And gallium arsenide is better than silicon in retaining its electricity-producing abilities in conditions of relatively low light, such as early in the morning or late in the afternoon.
Key to reducing its manufacturing costs is the technique that Yablonovitch helped figure out decades ago. The semiconductor can be grown epitaxially: when thin layers are chemically deposited on a substrate of single-crystal gallium arsenide, each adopts the same single-crystal structure. Yablonovitch found that if a layer of aluminum arsenide is sandwiched between the layers, this can be selectively eaten away with an acid, and the gallium arsenide above can be peeled off. It was an elegant and simple way to create thin films of the material. But the process was also problematic: the single-crystal films easily crack and become worthless. In adapting Yablonovitch's fabrication method, Alta researchers have found ways to create rugged films that aren't prone to cracking. And not only do the thin films use little of the semiconductor material, but the valuable gallium arsenide substrate can be reused multiple times, helping to make the process affordable.
Research by Alta's founding scientists has also led to techniques for increasing the performance of the solar cells. Photovoltaics work because the photons they absorb boost the energy levels of electrons in the semiconductor, freeing them up to flow to metal contacts and create a current. But the roaming electrons can be wasted in various ways, such as in heat. In gallium arsenide, however, the freed electrons frequently recombine with positively charged "holes" to re-create photons and start the process over again. Work done by ­Yablonovitch and Atwater to explain this process has helped Alta design cells to take advantage of this "photon recycling," providing many chances to recapture photons and turn them into electricity.
Thus Alta's efficiency record: its cells have converted 28.3 percent of sunlight into electricity, whereas the highest efficiency for a silicon solar cell is 25 percent, and commonly used thin-film solar materials don't exceed 20 percent. Yablonovitch suggests that Alta has a good chance of eventually breaking 30 percent efficiency and nearing the theoretical limit of 33.4 percent for cells of its type.
The high efficiency, combined with gallium arsenide's ability to perform at relatively high temperatures and in low light, means that the cells can produce two or three times more energy over a year than conventional silicon ones, says Norris. And that, of course, translates directly into lower prices for solar power. Norris says a "not unreasonable expectation" is that the gallium arsenide technology could yield a "levelized cost of energy" (a commonly used industry metric that includes the lifetime costs of building and operating a power plant) of seven cents per kilowatt-hour. At such a price, says Norris, solar would be competitive with fossil fuels, including natural gas; new gas plants generate electricity for around 10 cents per kilowatt-hour. And it would trounce today's solar power, which Norris says costs around 20 cents per kilowatt-hour to generate.
Such numbers are tantalizing. But Norris is quick to bring up another: it costs roughly $1 billion to build a manufacturing facility capable of producing enough solar modules to generate a gigawatt of power, which is roughly the output of several medium-sized power plants. "I don't see any scenario where we would do this on our own," he says.
GHOST OF SOLYNDRA
Silicon Valley has been infatuated with clean tech since the mid-2000s, but it has yet to figure out something crucial: who will supply all the money necessary to scale up energy technologies and build factories to manufacture them? Venture investors might be skilled at picking technologies, but few of them have the deep pockets or the patience required to compete in a capital-intensive business such as the manufacturing of solar modules. The collapse of Solyndra, which built a $733 million factory in Fremont, California, is just the most recent reminder of what can go wrong.
Alta's lead investor Andy Rappaport says he usually stays away from investments in clean tech, including photovoltaics. Many investors in solar, he suggests, have bet that a startup could lower the marginal costs of manufacturing and thus "capture some market share." That's "a recipe for failure," he says, because "you need to spend hundreds of millions to build a factory before you know if you have anything of value." The strategy is especially risky now, because photovoltaics are becoming an increasingly competitive commodity business and prices continue to plummet, creating a moving target for new production. But rather than trying to create value by building manufacturing capacity, Rappaport says, Alta can profit from its intellectual property: "We have said simply and consistently that we can scale capacity faster and build a much stronger company by leveraging partnerships rather than raising and spending our own capital to build factories."
Current investors in Alta include GE, Sumitomo, and Dow Chemical, which recently introduced roofing shingles that incorporate thin-film photovoltaics (see "Can We Build Tomorrow's Breakthroughs?" January/February 2012). Though these companies have invested in several rounds of funding—Alta has so far raised $120 million—eventually Norris would like to see deals, such as licensing agreements or joint ventures, in which manufacturers build capacity to produce Alta's solar cells or use the solar technology in their products. To do that, he says, Alta first needs to "retire the risk" of the production technology, demonstrating to prospective partners that the gallium arsenide solar modules can in fact be produced in an economically competitive way.
Less than a mile from its headquarters, Alta is gutting and renovating a building where Netflix used to warehouse DVDs, turning it into a $40 million pilot facility to test its equipment. Though the facility is far smaller than a commercial solar factory, it is still no small or inexpensive undertaking. Norris warily eyes the new columns required to reinforce the roof, which will need to hold heavy ventilation and emission-control equipment. But the Alta CEO becomes more buoyant as he approaches the nearly completed back section of the facility. There, in several white rooms, are the large custom-designed versions of the lab apparatus used to make the solar cells.
Whether Alta succeeds will depend chiefly on how well these manufacturing inventions perform. The cost of the pilot facility might pale next to the price tag for a commercial-scale solar factory, but it is still a critical investment for the startup. And even as Alta is busily trying to get the facility up and running by the end of the year, Norris says, it is taking a deliberate, methodical approach to the process of scaling up. That contrasts sharply with earlier solar startups that spent hundreds of millions in venture investments to build factories as fast as possible. But Alta's cautious approach should not be confused with a lack of ambition. The goal, says Norris, is to make this a "foundational, transformative technology."

An Inventor at Heart

An Inventor at Heart

Inspired by lessons he learned at MIT, Ronald Berger '81 is trying to perfect a painless method of preventing cardiac arrest.
  • March/April 2012
  • By Genevieve Wanucha, SM '09
Credit: Michael Northrup
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At the Boston Museum of Science, audiences gather around the Van de Graaff generator to watch as two million volts crackle between twin metal spheres while the operator, who stands nearby inside a simple cage, remains unaffected. This lightning show demonstrates a Faraday cage, an enclosure that keeps electrical charges from getting in—or out. In 1999, when Ronald Berger '81, SM '83, PhD '87, took his kids to the Boston spectacle, it wasn't just for fun. He was in the midst of a plot to fit a Faraday cage around the human heart.
If Berger can make it work, his device will improve conditions for patients with heart problems. Sudden cardiac arrest, a leading cause of death, results from a severe arrhythmia called ventricular fibrillation. In this emergency, the only way to restore normal rhythm is with a defibrillator, which delivers a chest-seizing wallop of hundreds or thousands of volts. For more than three decades, patients considered at risk for heart attacks have been able to get an internal cardiac defibrillator (ICD) installed beneath the skin to detect irregular heartbeats. A wire that passes from the ICD into the heart through a vein delivers shocks as needed. However, the shocks are painful, and patients often live in dread of them or choose to forgo treatment because of them. "It's an important problem," Berger says. "I've been very interested in making defibrillation painless." And a type of ­Faraday cage could be the answer.
Berger, who is co-director of cardiac electrophysiology at Johns Hopkins, earned three MIT degrees in electrical engineering and computer science and then completed his MD through the Harvard-MIT Division of Health Sciences and Technology in 1987. Mirroring his education, he is both engineer and doctor. More specifically, he is a cardiac electrophysiologist—one who understands that "we can actually fool Mother Nature and interrupt the propagation of the [electrical] impulse in hearts," as he puts it. Berger spends 75 percent of his time at Johns Hopkins teaching, serving as an administrator, and performing procedures to quiet cardiac electrical dysfunction, or arrhythmia. The rest of the time, he researches and invents.
Berger has always invented. For his undergraduate thesis at MIT, he designed a new way to steer and deflect laser beams through crystals. The result, recalls his thesis advisor, EECS professor Cardinal Warde, "was one of the best undergraduate theses ever done in my laboratory." Soon after Berger met his best friend, Joseph Smith, SM '82, PhD '85, in the lab of MIT biomedical engineer ­Richard Cohen in 1980, they turned a black-and-white handheld TV into an EKG machine capable of reading the heart's electrical activity at the surface of the body. Today, Berger has been issued 25 patents for cardiology methods and equipment.
Fifteen years ago, Berger became fixated on the pain that ICD shocks caused his patients. He knew that the pain wasn't coming from the heart. The organ itself has so little capacity for pain sensation that patients can stay wide awake as cardiologists perform ablation, burning away chronically malfunctioning heart tissue with a wire that's been snaked up through a blood vessel. So Berger concluded that electrical pulses from the ICD must leak out as the nerves and muscles of the chest wall activate.
Something clicked. "I said to myself, wouldn't it be cool if there was a way to keep the electrical activity confined to the heart?" Berger says. That's when he was reminded of a lesson on the Faraday cage from 8.022, Electricity and Magnetism, a class he had taken with Professor Claude Canizares back in 1977. Berger wondered if it would be possible to sheathe the heart inside a Faraday cage to contain a shock that halted arrhythmia.
One problem, however, is that a Faraday cage around the heart would not just keep electricity confined to the heart; it would also block electricity from another source from entering. This meant that patients would be unable to get emergency external defibrillation if their heart failure were extreme enough to require a bigger shock. To deal with that, Berger began to think about a configuration of metal panels that would not be entirely contiguous. They would merely be close enough to act as a Faraday cage when electricity passed through them. He recalls that a research fellow mentioned the idea to his wife, who suggested sewing the metal mesh into a nylon stocking. She even produced a prototype. It was a Faraday cage—or, more accurately, a Faraday sock.
Electric shock: Ronald Berger’s prototype cardiac sock is made of multiple flexible electrodes that are electrically joined together to act as a Faraday cage. The Faraday cage prevents leakage of the electric field to surrounding tissues, reducing the pain caused by the shock of an implanted defibrillator. Credit: Courtesy of Dr. Ronald Berger
In practice, the sock would fit around the heart and serve as one electrode of the shock delivery circuit; when an attached sensor detected abnormal heart activity, an electrical coil implanted inside the heart would deliver the jolt. In 2005, when Berger and his research team tested the prototype in dogs, the device reset the heartbeat using less energy than a standard ICD. Most important, the dogs' chest muscles contracted much less, meaning that less electricity was seeping out and causing pain.
Berger and Johns Hopkins colleagues have refined the design in the past year, using mathematical modeling to find the optimal spacing for the panels. In the most recent version, the panels electrically unite into a contiguous shield and act as a Faraday cage only in the 10 milliseconds right before and during the moment in which the shock is delivered.
Despite the progress, some cardiac experts question the sock's potential. Bioengineer Igor Efimov at Washington University in St. Louis points out that covering the heart with the mesh would require major open-chest surgery. "Who would agree to such a dramatic surgery with unclear clinical benefits?" he says. He also predicts that scar tissue would encrust the device's wire slats and prevent them from opening. "Unless there is a breakthrough in biomaterials, I don't think it could be used," he says. Berger agrees that scar tissue could be a problem, but he holds out hope that his invention can work. He notes that private companies have already invented socks made of elastic mesh to reduce heart muscle stress in patients with heart failure. Berger suggests that his Faraday cage might be built into one of those socks. Heart patients who already need invasive surgery to implant the sock could get a two-for-one solution.
Berger and his friend Smith, who is now chief medical officer for West Wireless Health Institute, have spent many a Baltimore night discussing the Faraday sock and how Berger might bring it to fruition. "It's one of those things that only comes from a bright engineer being able to understand the problem from a physics perspective but also see the clinical applications," Smith says.
These two complementary talents started to meld not long after Berger began at MIT in 1976. One day, he walked into the office of his advisor, George W. Pratt, and noticed a large painting of a horse. He was puzzled until Pratt, a horse-racing enthusiast, began drawing chalk diagrams of electrical resistors and capacitors to model the equine blood system; the heart was acting like a battery and the blood vessels like a charged capacitor. For Berger, these lessons are still a revelation 35 years later. He says, "It's an amazing thing—the principles of electrical engineering underlie how one native impulse in the heart gets from one cell to the next."
Today Berger is trying to improve defibrillation in the very place the technique was born. In 1933, a New York electric company funded efforts by Johns Hopkins researchers to find solutions for the frequent electrocution accidents of the era; after studying what happens when a heart's rhythm is off course, these men were the first to get a dog's heart to stop fibrillating. Hopkins physicians implanted the first ICD into a patient in 1980.
But though the technology has its roots in the Johns Hopkins clinic, Berger says his mind goes back to MIT every day. "I always say that performing ablation reminds me very much of my undergraduate course 6.082, where we would move the probe from point to point within a circuit to debug it," he says. He thinks of those lab projects each time he inches the catheter's tip to the right place in a patient's heart and watches the arrhythmia disappear as he delivers the burn.