Friday, July 16, 2010

RENEWABLES ACCOUNT FOR 62 PERCENT OF THE NEW ELECTRICITY GENERATION CAPACITY INSTALLED IN THE EU IN 2009

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In 2009, and in absolute terms, about 19.9% (608 TWh) of Europe's total electricity consumption (3042 TWh) came from renewable energy sources. Hydro power contributed with the largest share (11.6%), followed by wind (4.2%), biomass (3.5%), and solar (0.4%).

With regards to the new capacity constructed that same year (27.5 GW), among the renewable sources, 37.1% was wind power, 21% photovoltaics (PV), 2.1% biomass, 1.4% hydro and 0.4% concentrated solar power, whereas the rest were gas fired power stations (24%), coal fired power stations (8.7%), oil (2.1%), waste incineration (1.6%) and nuclear (1.6%).

As not all installed technologies operate continuously 24 hours a day, figure 2 shows the expected yearly energy output (TWh) from the new capacity. The new gas-fired electricity plants will deliver yearly 28 TWh, followed by wind and PV with 20 TWh and 5.6 TWh, respectively.

If current growth rates are maintained, in 2020 up to 1400 TWh of electricity could be generated from renewable sources, the report concludes. This would account for approximately 35-40% of overall electricity consumption in the EU, depending on the success of community policies on electricity efficiency, and would contribute significantly to the fulfilment of the 20% target for energy generation from renewables.

However, it also advises that some issues need to be resolved if the targets are to be met. Particular areas of focus include ensuring fair access to grids, substantial public R&D support, and the adaptation of current electricity systems to accommodate renewable electricity. The study highlights that cost reduction and accelerated implementation will depend on the production volume and not on time.

Wind energy: with more than 74 GW of total installed capacity in 2009, it has already exceeded the 2010 white paper target of 40 GW by more than 80%. The European Wind Association's new target aims for 230 GW of installed capacity (40 GW offshore) by 2020, capable of providing about 20% of Europe's electricity demand.

Biomass: if current growth continues, electricity output from biomass could double from 2008 to 2010 (from 108 TWh to 200 TWh). However, other energy uses such as heat and transport fuels compete for this particular source, which could potentially hinder the development of bioelectricity. Being storable for use on demand increases its importance as a source of electricity.

Concentrated Solar Power (CSP): installed capacity is still relatively small in Europe: 0.430 GW in May 2010, about 0.5% of the total, but is steadily increasing. An estimated 30 GW could be installed by 2020 if the European Solar Industry Initiative ESII is realised. Most CSP projects currently under construction are located in Spain.

Solar Photovoltaic: since 2003, the total installed capacity has doubled each year. In 2009 it reached 16 GW, which represents 2% of the overall capacity. The growth will continue, as for 2010, installations of up to 10 GW are expected. Solar photovoltaic has also exceeded the capacity predictions formulated by in the EU white paper on renewable sources of energy.

Other sources of power: technologies such as geothermal, tidal and wave power are still at the R&D stage, so they have not yet been included in the Renewable Energy Snapshots. Yet, they are likely to be introduced to the market within the next decade. As far as hydro generation is concerned, no major increase is expected, as most of the resources are already in use. However, pumped hydro will play an increasingly important role as in a storage capacity for the other renewable energy resources.

(Photo: © Jesper Baerentzen)

European Commission Joint Research Centre

WHY YOU SHOULD NEVER ARM WRESTLE A SABER-TOOTHED TIGER

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Saber-toothed cats may be best known for their supersized canines, but they also had exceptionally strong forelimbs for pinning prey before delivering the fatal bite, says a new study in the journal PLoS ONE.

Commonly called the "saber-toothed tiger," the extinct cat Smilodon fatalis roamed North and South America until 10,000 years ago, preying on large mammals such as bison, camels, mastodons and mammoths. Telltale clues from bones and teeth suggest they relied on their forelimbs as well as their fangs to catch and kill their prey.

The size and shape of sabertooth canines made them more vulnerable to fracture than cats living today, said author Julie Meachen-Samuels, a paleontologist at the National Evolutionary Synthesis Center in Durham, NC.

"Cats living today have canines that are round in cross-section, so they can withstand forces in all directions. If the prey is struggling it doesn't matter which way it's pulling — their teeth are unlikely to break," she explained.

In contrast, the elongated canines of saber-toothed cats were oval in cross-section, which made them more vulnerable to breaking than their conical-toothed cousins. "Many scientists infer that saber-toothed cats killed prey differently from other cats because their teeth were thinner side-to-side," said Meachen-Samuels.

Despite their vulnerable canines, prominent muscle attachment scars on sabertooth limb bones suggest the cat was powerfully built. Saber-toothed cats may have used their muscular arms to immobilize prey and protect their teeth from fracture, she explained.

To estimate how strong sabertooth forelimbs were relative to other cats, the researchers used x-rays to measure the cross-sectional dimensions of the upper arm and leg bones of fossils recovered from the La Brea Tar Pits in Los Angeles. They also measured the limb bones of 28 cat species living today — ranging in size from the 6-pound margay to the 600-pound tiger — as well as the extinct American lion, the largest conical-toothed cat that ever lived.

The researchers used their cross-sectional measurements to estimate bone strength and rigidity for each species. When they plotted rigidity against length for the 30 species in their study, species with longer limbs generally had stronger bones. But the data for the saber-toothed cat fell well outside the normal range —while their leg bones scaled to size, their arm bones were exceptionally thick for their length.

"When I looked at the arm bones, Smilodon fatalis was way out in left field," said Meachen-Samuels.

Sabertooth arm bones were not only larger in diameter than other cats, they also had thicker cortical bone, the dense outer layer that makes bones strong and stiff. Thicker cortical bone is consistent with the idea that sabertooth forelimbs were under greater stress than would be expected for cats their size, Meachen-Samuels explained. Just like weight-bearing exercise remodels our bones and improves bone density over time, the repeated strain of grappling with prey may have resulted in thicker and stronger arm bones in saber-toothed cats.

"As muscles pull on bones, bones respond by getting stronger," said Meachen-Samuels. "Because saber-toothed cats had thicker arm bones we think they must have used their forelimbs more than other cats did."

"The findings give us new information about how strong their forelimbs were and how they were built," she added. "This is the first study to look inside sabertooth arm bones to see exactly how much stress and strain they could handle."

(Photo: Wikimedia Commons)

National Evolutionary Synthesis Center

OUR BRAINS ARE MORE LIKE BIRDS' THAN WE THOUGHT

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For more than a century, neuroscientists believed that the brains of humans and other mammals differed from the brains of other animals, such as birds (and so were presumably better). This belief was based, in part, upon the readily evident physical structure of the neocortex, the region of the brain responsible for complex cognitive behaviors.

A new study, however, by researchers at the University of California, San Diego School of Medicine finds that a comparable region in the brains of chickens concerned with analyzing auditory inputs is constructed similarly to that of mammals.

"And so ends, perhaps, this claim of mammalian uniqueness," said Harvey J. Karten, MD, professor in the Department of Neurosciences at UCSD's School of Medicine, and lead author of the study, published in the Proceedings of the National Academy of Sciences Online Early Edition.

Generally speaking, the brains of mammals have long been presumed to be more highly evolved and developed than the brains of other animals, in part based upon the distinctive structure of the mammalian forebrain and neocortex – a part of the brain's outer layer where complex cognitive functions are centered.

Specifically, the mammalian neocortex features layers of cells (lamination) connected by radially arrayed columns of other cells, forming functional modules characterized by neuronal types and specific connections. Early studies of homologous regions in nonmammalian brains had found no similar arrangement, leading to the presumption that neocortical cells and circuits in mammals were singular in nature.

For 40 years, Karten and colleagues have worked to upend this thinking. In the latest research, they used modern, sophisticated imaging technologies, including a highly sensitive tracer, to map a region of the chicken brain (part of the telencephalon) that is similar to the mammalian auditory cortex. Both regions handle listening duties. They discovered that the avian cortical region was also composed of laminated layers of cells linked by narrow, radial columns of different types of cells with extensive interconnections that form microcircuits that are virtually identical to those found in the mammalian cortex.

The findings indicate that laminar and columnar properties of the neocortex are not unique to mammals, and may in fact have evolved from cells and circuits in much more ancient vertebrates.

"The belief that cortical microcircuitry was a unique property of mammalian brains was largely based on the lack of apparent lamination in other species, and the widespread notion that non-mammalian vertebrates were not capable of performing complex cognitive and analytic processing of sensory information like that associated with the neocortex of mammals," said Karten.

"Animals like birds were viewed as lovely automata capable only of stereotyped activity."

But this kind of thinking presented a serious problem for neurobiologists trying to figure out the evolutionary origins of the mammalian cortex, he said. Namely, where did all of that complex circuitry come from and when did it first evolve?

Karten's research supplies the beginnings of an answer: From an ancestor common to both mammals and birds that dates back at least 300 million years.

The new research has contemporary, practical import as well, said Karten. The similarity between mammalian and avian cortices adds support to the utility of birds as suitable animal models in diverse brain studies.

"Studies indicate that the computational microcircuits underlying complex behaviors are common to many vertebrates," Karten said. "This work supports the growing recognition of the stability of circuits during evolution and the role of the genome in producing stable patterns. The question may now shift from the origins of the mammalian cortex to asking about the changes that occur in the final patterning of the cortex during development."

University of California, San Diego

CHOLESTEROL'S OTHER WAY OUT

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Many of us are simply overloaded with cholesterol, and now a report in the July issue of Cell Metabolism brings what might be good news: There is more than one way to get rid of that cholesterol, which can otherwise lead to atherosclerosis and heart disease.

"Cholesterol really can't be broken down," said Mark Brown of Wake Forest University School of Medicine. To get rid of it, it must be excreted, and now Brown and his colleagues have new evidence for an alternate way to deliver cholesterol into the feces. The findings revise scientific dogma about cholesterol loss that goes back almost 40 years.

Textbooks say that white blood cells known as macrophages gobble up cholesterol from artery walls. That cholesterol is then delivered to high-density lipoprotein [HDL, aka good cholesterol], which takes it back to the liver where it goes into bile.

"Bile is necessary under the model to deliver cholesterol to the intestine," Brown said.

There were some hints that might not be the whole story. A model of cholesterol loss first proposed way back in the 1920s suggested the existence of a route that didn't rely on bile. And indeed, studies in dogs unable to get cholesterol into bile showed that the animals actually experienced an increase in cholesterol loss. More recent studies in mice showed a similar thing.

Even so, the researchers said that an alternative pathway has largely been ignored. As a result, scientists have made very little progress in defining the molecular pathways and players involved.

Now, Brown and his colleagues offer new evidence that helps support and clarify this alternate path for cholesterol. They report that mice made unable to secrete cholesterol into bile through genetic manipulation or surgery still lose cholesterol through the feces at a normal rate. Macrophages in those animals also continued to take up cholesterol from blood vessels.

The researchers believe that alternate path delivers cholesterol from the liver to the intestine directly through the bloodstream.

"The classic view of reverse cholesterol transport involved the delivery of peripheral cholesterol via HDL to the liver for secretion into bile," the researchers wrote. "In parallel, we believe that the liver also plays a gatekeeper role for nonbiliary fecal sterol loss by repackaging peripheral cholesterol into nascent plasma lipoproteins that are destined for subsequent intestinal delivery."

For the purposes of cholesterol-lowering drug discovery, it may prove fruitful to consider those two pathways as "separate and complementary," Brown said.

There is some reason to think that drugs aimed to increase cholesterol loss without relying on bile might come with fewer side effects. That's because an excess of cholesterol in bile can lead to gallstones.

"You don't necessarily want to increase cholesterol in the bile," Brown said. And now it seems, there might be a way to get rid of cholesterol without having to.

Cell Press

REVERSIBLE WATERMARKING FOR DIGITAL IMAGES

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Every picture tells a story, but how do you know that a digital photo has not been manipulated to change the tale being told? A new approach to adding an encrypted watermark to digital images allows the an image to be validated against a pass key, according to research published in the International Journal of Signal and Imaging Systems Engineering.

Visible watermarks are routinely added to digital images as a form of copy protection, but their presence essentially destroys the picture, obliterating information within altered pixels in a way that cannot be reversed. Now, Dakshinamurthi Sivakumar and Govindarajan Yamuna of Annamalai University, in Tamil Nadu, India, have developed a new, reversible watermarking scheme. The system could be used initially for the authentication of military images.

Inexpensive image editing software is now available that can be used to make essentially undetectable "photo realistic" changes to almost any photograph, the team explains. In a military setting it is important to prevent unauthorized manipulation of digital images and to be able to demonstrate credibility and provenance.

"Traditionally, source authentication and integrity verification of digital data have been carried out with digital signatures and encrypted watermarks," the team says, "Unfortunately, watermarking techniques modify original data as a modulation of the watermark information and unavoidably cause permanent distortion to the original data." Reversible, or lossless, watermarking is therefore required for many highly sensitive applications.

The team has now developed a reversible watermarking system based on calculating the parameters of every pixel in the image but nevertheless at low computer power. This information is converted into a code, a Hash Message Authentication Code (HMAC), of the image where distinct pixel values are selected for embedding watermark bits and the preferred pixel values are stored as a key. The key thus generated is used for both the watermark extraction and restoration of the original image. The extracted HMAC and the HMAC of the restored image can be compared to verify that the received image is authentic and has not been altered.

Inderscience Publishers

HIPS DONT LIE: RESEARCHERS FIND MORE ACCURATE TECHNIQUE TO DETERMINE SEX OF SKELETAL REMAINS

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Research from North Carolina State University offers a new means of determining the sex of skeletal human remains – an advance that may have significant impacts in the wake of disasters, the studying of ancient remains and the criminal justice system.

Historically, forensic scientists have been able to determine the sex of skeletal remains by visually evaluating the size and shape of the pelvis, or os coxa. “This technique is accurate, but is not without its limitations,” says Dr. Ann Ross, associate professor of sociology and anthropology at NC State and co-author of a paper describing the research.

The new technique for determining the sex of skeletal human remains is significantly more accurate than traditional visual inspections.

“For example,” Ross says, “when faced with fragmentary remains of the os coxa, it can be difficult to determine the deceased person’s sex based solely on visual inspection. This can be a significant challenge when evaluating remains from disasters – such as plane crashes – or degraded remains in mass burials – whether the burials date from prehistory or 20th century political violence.”

But Ross and her colleague Dr. Joan Bytheway have now used three-dimensional imaging technology to effectively quantify the specific characteristics of the os coxa that differentiate males from females. Bytheway is an assistant professor of forensic science at Sam Houston State University.

The researchers found more than 20 anatomical “landmarks” on the os coxa that can be used to determine a body’s sex. Finding so many landmarks is important, Ross says, because it means that the sex of a body can be ascertained even if only a small fragment of the pelvis can be found. In other words, even if only 15 percent of the pelvis is recovered, it is likely that at least a few of the landmarks can be found on that fragment.

Here’s how it would work: a forensic scientist would use a digitizer to create a 3-D map of the pelvic fragment and measure the relevant anatomical landmarks. The scientist could then determine the sex of the remains by comparing those measurements to the measurements listed in the paper by Bytheway and Ross.

“This technique also has the benefit of being significantly more accurate than traditional visual inspections,” Ross says. While determining sex based on visual inspections of os coxa have an accuracy rate of approximately 90 percent, the new technique from Ross and Bytheway has an accuracy rate of 98 percent or better. The researchers found, for example, that several anatomical landmarks commonly used in visual inspection to estimate sex are actually very poor indicators of sex.

The new technique could also have significant benefits in the courtroom. Obviously the improved accuracy is important, but so is the fact that the method relies on quantifiable metric data – not an opinion. This is an important distinction under the federal rules of evidence that govern what evidence can be submitted in criminal court.

The researchers are planning to incorporate their findings into the National Institute of Justice’s 3D-ID program. The 3D-ID program consists of software that allows forensic scientists to plug in data on skeletal remains and determine the sex and ancestral origin of those remains.

(Photo: NCSU)

North Carolina State University

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