Surprising demographic shifts in endangered monkey population challenge conservation expectations

ScienceDaily (Sep. 18, 2012) — At first glance, the northern muriqui monkey is a prime conservation success story. These Brazilian primates are critically endangered, but in the past 30 years a population on a private reserve has grown from just 60 individuals to some 300, now comprising almost a third of the total remaining animals.

As the population grows, though, it is offering researchers a glimpse into a new phase of recovery as it begins to face the limitations of its habitat. A recent analysis of the factors contributing to this population's tremendous growth reveals surprising trends that raise new questions about conservation, recovery and what constitutes a healthy population.

University of Wisconsin-Madison anthropologist Karen Strier has led observational field studies of this muriqui population for 30 years, meticulously charting demographics and life history of hundreds of individual monkeys. An analysis, published Sept. 17 in the journal PLOS ONE with UW-Madison mathematical ecologist Anthony Ives, provides the most comprehensive, quantitative look to date at long-term demographic trends and the role of individual features such as fertility, mortality, and sex ratios.

The researchers used statistical models designed to handle multiple levels of data so they could construct a comprehensive view of the population while still accounting for variation among individual animals. The approach allowed them to identify specific demographic trends and their effects on the overall population size.

"By separating out these components we were able to see the patterns in the data," Strier says, many of which were unexpected. For example, the analyses revealed increases in both fertility and mortality -- a surprising combination, especially in a population that is still growing. In addition, they documented a remarkable and unexplained shift in infant birth sex ratios from about one-third male to two-thirds male in just 28 years.

"It is an analysis that leads to more questions than answers," Ives says. A birth rate that continues to grow as the population expands flies in the face of most ecological thinking, he says, since demand for resources by larger populations usually reduces fertility. But without the observed fertility increases, the muriqui population would likely have plateaued around 200 individuals; instead, it has reached 300 and is still growing.

Strier believes the trends may be driven by behavioral changes. Though muriquis are typically arboreal animals, her field team has observed increased use of the ground -- first for drinking and eating, then gradually for traveling, playing, and even mating. These data are still qualitative, but she suspects this behavioral innovation could help explain the rises in both fertility and mortality. The ground expands the monkeys' pool of available habitat and food resources but exposes them to additional dangers as well.

"On the ground, there are risks. We suspect there may be more pathogenic risks, and we know there are more predators," she says. Supporting a connection, mortality increased primarily in prime-aged males, who spend more time on the ground than females. "I've always thought it was increasing population size that was driving this increasing use of the ground, but never thought about what the potential consequences of the use of the ground might be for the population's rate of growth," she adds.

The apparent interactions between demography and behavior emphasize the need for ongoing population monitoring, Strier says. Her long-term study, in collaboration with Brazilian colleagues including biologist Sergio Mendes of the Universidade Federal do Espirito Santo, is showing that assumptions about population dynamics based on past observations may not hold true in the future.

Ives views the results as a cautionary tale for other threatened and endangered species, the vast majority of which are not monitored anywhere near as closely as Strier's muriquis.

"From the conservation standpoint I think a main message is, don't presume that the demographics will respond in a 'normal' way," he says. "Even if an area is protected you need to have a close gauge on what's going on. Protecting an area is not necessarily protecting a species."

Strier agrees that the analysis raises important questions about environmental carrying capacity -- basically, how large of a population a habitat can support. "How long will it be able to grow, and if it does continue to grow, is it in danger of crashing?" she asks.

These are critical questions when considering management decisions, she adds, especially given that her study population represents a third of the entire muriqui species. On paper, population growth alone can look like success, but their demographic analysis reveals early indications of stress even as the population continues to expand.

At the same time, Strier says, their studies suggest a solution. "We know exactly what we need to do to alleviate it -- expand the area, and there is area to expand the forest into. In a world with so many unsolvable problems, this seems like a solvable one."

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The above story is reprinted from materials provided by University of Wisconsin-Madison. The original article was written by Jill Sakai.

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Journal Reference:

1. Karen B. Strier, Anthony R. Ives. Unexpected Demography in the Recovery of an Endangered Primate Population. PLoS ONE, 2012; 7 (9): e44407 DOI: 10.1371/journal.pone.0044407

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19 Sep, 2012

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Comet may have exploded over Canada 12,900 years ago after all

ScienceDaily (Sep. 18, 2012) — Did a massive comet explode over Canada 12,900 years ago, wiping out both beast and man in North America and propelling Earth back into an ice age?

That's a question that has been hotly debated by scientists since 2007, with the University of South Carolina's Topper archaeological site right in the middle of the comet impact controversy. However, a new study published Sept.17 in the Proceedings of the National Academy of Sciences (PNAS) provides further evidence that it may not be such a far-fetched notion.

USC archaeologist Albert Goodyear is a co-author on the study that upholds a 2007 PNAS study by Richard Firestone, a staff scientist at the Department of Energy's Lawrence Berkeley National Laboratory.

Firestone found concentrations of spherules (micro-sized balls) of metals and nano-sized diamonds in a layer of sediment dating 12,900 years ago at 10 of 12 archaeological sites that his team examined. The mix of particles is thought to be the result of an extraterrestrial object, such as a comet or meteorite, exploding in Earth's atmosphere. Among the sites examined was USC's Topper, one of the most pristine U.S. sites for research on Clovis, one of the earliest ancient peoples.

"This independent study is yet another example of how the Topper site with its various interdisciplinary studies has connected ancient human archaeology with significant studies of the Pleistocene," said Goodyear, who began excavating Clovis artifacts in 1984 at the Topper site in Allendale, S.C. "It's both exciting and gratifying."

Younger-Dryas is what scientists refer to as the period of extreme cooling that began around 12,900 years ago and lasted 1,300 years. While that brief ice age has been well-documented -- occurring during a period of progressive solar warming after the last ice age -- the reasons for it have long remained unclear. The extreme rapid cooling that took place can be likened to the 2004 sci-fi blockbuster movie "The Day After Tomorrow."

Firestone's team presented a provocative theory: that a major impact event -- perhaps a comet -- was the catalyst. His copious sampling and detailed analysis of sediments at a layer in the Earth dated to 12,900 years ago, also called the Younger-Dryas Boundary (YDB), provided evidence of micro-particles, such as iron, silica, iridium and nano-diamonds. The particles are believed to be consistent with a massive impact that could have killed off the Clovis people and the large North American animals of the day. Thirty-six species, including the mastodon, mammoth and saber-toothed tiger, went extinct.

The scientific community is rarely quick to accept new theories. Firestone's theory and support for it dominated the annual meeting of the American Geophysical Union and other gatherings of Paleoindian archaeologists in 2007 and 2008.

However, a 2009 study led by University of Wyoming researcher Todd Surovell failed to replicate Firestone's findings at seven Clovis sites, slowing interest and research progress to a glacial pace.

This new PNAS study refutes Surovell's findings with its lack of reported evidence.

"Surovell's work was in vain because he didn't replicate the protocol. We missed it too at first. It seems easy, but unless you follow the protocol rigorously, you will fail to detect these spherules. There are so many factors that can disrupt the process. Where Surovell found no spherules, we found hundreds to thousands," said Malcolm LeCompte, a research associate professor at Elizabeth City State University and lead author of the newly released PNAS article.

LeCompte began his independent study in 2008 using and further refining Firestone's sampling and sorting methods at two sites common to the three studies: Blackwater Draw in New Mexico and Topper. He also took samples at Paw Paw Cove in Maryland, a site common to Surovell's study.

At each site he found the same microscopic spherules, which are the diameter of a human hair and distinct in appearance. He describes their look as tiny black ball bearings with a marred surface pattern that resulted from being crystalized in a molten state and then rapidly cooled. His investigation also confirmed that the spherules were not of cosmic origin but were formed from earth materials due to an extreme impact.

LeCompte said it was Topper and Goodyear's collaboration, however, that yielded the most exciting results.

"What we had at Topper and nowhere else were pieces of manufacturing debris from stone tool making by the Clovis people. Topper was an active and ancient quarry at the time," LeCompte said. "Al Goodyear was instrumental in our approach to getting samples at Topper."

Goodyear showed LeCompte where the Clovis level was in order to accurately guide his sampling of sediments for the Younger Dryas Boundary layer. He advised him to sample around Clovis artifacts and then to carefully lift them to test the sediment directly underneath.

"If debris was raining down from the atmosphere, the artifacts should have acted as a shield preventing spherules from accumulating in the layer underneath. It turns out it really worked!" Goodyear said. "There were up to 30 times more spherules at and just above the Clovis surface than beneath the artifacts."

LeCompte said the finding is "critical and what makes the paper and study so exciting. The other sites didn't have artifacts because they weren't tool-making quarries like Topper."

While the comet hypothesis and its possible impact on Clovis people isn't resolved, Goodyear said this independent study clarifies why the Surovell team couldn't replicate the Firestone findings and lends greater credibility to the claim that a major impact event happened at the Younger Dryas Boundary 12,900 years ago.

"The so-called extra-terrestrial impact hypothesis adds to the mystery of what happened at the YDB with its sudden and unexplained reversion to an ice age climate, the rapid and seemingly simultaneous loss of many Pleistocene animals, such as mammoths and mastodons, as well as the demise of what archaeologists call the Clovis culture," Goodyear said. "There's always more to learn about the past, and Topper continues to function as a portal to these fascinating mysteries."

Goodyear joined USC's College of Arts and Sciences and its South Carolina Institute for Archaeology and Anthropology in 1974 to pursue prehistoric archaeology.

The Topper story

Al Goodyear, who conducts research through the University of South Carolina's S.C. Institute of Anthropology and Archaeology, began excavating Clovis artifacts along the Savannah River in Allendale County in 1984. It quickly became one of the most documented and well-known Clovis sites in the United States. In 1998, with the hope of finding evidence of a pre-Clovis culture earlier than the accepted 13,100 years, Goodyear began focused excavations on a site called Topper, located on the property of the Clariant Corp.

His efforts paid off. Goodyear unearthed small tools such as scrapers and blades made of the local chert that he believed to be tools of an ice age culture back some 16,000 years or more. His findings, as well as similar ones yielded at other pre-Clovis sites in North America, sparked great change and debate in the scientific community.

Goodyear reasoned that if Clovis and later peoples used the chert quarry along the Savannah River, the quarry could have been used by even earlier cultures.

Acting on a hunch in 2004, Goodyear dug even deeper into the Pleistocene terrace and found more artifacts of a pre-Clovis type buried in a layer of sediment stained with charcoal deposits. Radiocarbon dates of the burnt plant remains yielded ages of 50,000 years, which suggested man was in South Carolina long before the last ice age.

Goodyear's findings not only captured international media attention, but it has put the archaeology field in flux, opening scientific minds to the possibility of an even earlier pre-Clovis occupation of the Americas.

Since 2004, Goodyear has continued his Clovis and pre-Clovis excavations at Topper. With support of Clariant Corp. and SCANA, plus numerous individual donors, an expansive shelter and viewing deck now sit above the dig site to allow Goodyear and his team of graduate students and public volunteers to dig free from the heat and rain and to protect what may be the most significant early-man dig in America.

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The above story is reprinted from materials provided by University of South Carolina, via Newswise.

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Journal Reference:

1. M. A. LeCompte, A. C. Goodyear, M. N. Demitroff, D. Batchelor, E. K. Vogel, C. Mooney, B. N. Rock, A. W. Seidel. PNAS Plus: Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1208603109

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18 Sep, 2012

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Sea surface temperatures reach record highs on Northeast continental shelf

ScienceDaily (Sep. 18, 2012) — During the first six months of 2012, sea surface temperatures in the Northeast Shelf Large Marine Ecosystem were the highest ever recorded, according to the latest Ecosystem Advisory issued by NOAA's Northeast Fisheries Science Center (NEFSC). Above-average temperatures were found in all parts of the ecosystem, from the ocean bottom to the sea surface and across the region, and the above average temperatures extended beyond the shelf break front to the Gulf Stream.

The annual 2012 spring plankton bloom was intense, started earlier and lasted longer than average. This has implications for marine life from the smallest creatures to the largest marine mammals like whales. Atlantic cod continued to shift northeastward from its historic distribution center.

The Northeast US Continental Shelf Large Marine Ecosystem (LME) extends from the Gulf of Maine to Cape Hatteras, North Carolina. The NEFSC has monitored this ecosystem with comprehensive sampling programs from 1977 onward; prior to 1977, this ecosystem was also monitored by the NEFSC through a series of separate but coordinated programs dating back decades.

"A pronounced warming event occurred on the Northeast Shelf this spring, and this will have a profound impact throughout the ecosystem," said Kevin Friedland, a scientist in the NEFSC's Ecosystem Assessment Program. "Changes in ocean temperatures and the timing of the spring plankton bloom could affect the biological clocks of many marine species, which spawn at specific times of the year based on environmental cues like water temperature."

Friedland said the average sea surface temperature (SST) exceeded 10.5 degrees C (51°F) during the first half of 2012, exceeding the previous record high in 1951. Average SST has typically been lower than 9 degrees C (48°F) over the past three decades. Sea surface temperature in the region is based on both contemporary satellite remote-sensing data and long-term ship-board measurements, with historical SST conditions based on ship-board measurements dating back to 1854.

In some nearshore locations like Delaware and Chesapeake Bays in the Middle Atlantic Bight region, temperatures were more than 6 degrees C (11°F) above historical average at the surface and more than 5 degrees C (9°F) above average at the bottom. In deeper offshore waters to the north, bottom waters were 1 degree C (2°F) warmer in the eastern Gulf of Maine and greater than 2 degrees C (3.6°F) warmer in the western Gulf of Maine.

The ocean bottom temperature data came from a variety of sources, including eMOLT, a cooperative research program between the Northeast Fisheries Science Center and lobstermen who deploy temperature probes attached to lobster traps. While some of the temperature probes from the eMOLT program are still in the water and have not yet been returned, those that have been returned indicate that bottom water temperatures in 2012 were the warmest since the eMOLT program began in 2001.

Atlantic cod distribution in the Gulf of Maine continues a northeasterly shift, with the spring 2012 data consistent with a response to ecosystem warming. Warming ocean temperatures and the resulting impact on the distribution of 36 fish stocks was reported by the Center in a 2009 study published in Marine Ecology Progress Series. That study analyzed annual NEFSC spring survey data from 1968 to 2007 and other information and found that about half of the 36 fish stocks studied in the Northwest Atlantic Ocean, many of them commercially valuable species, have been shifting northward over the past four decades, with some disappearing from US waters as they move farther offshore.

Friedland notes that although cod didn't shift as much as other species like hake in the 2009 study, the effects of warming water on ocean currents and other ocean circulation patterns could change that. "Cod distribution continues to be dynamic, with northerly shifts detected in the spring 2012 data, consistent with a response to ecosystem warming," Friedland said. "The big question is whether or not these changes will continue, or are they a short-term anomaly?"

Mike Fogarty, who heads the Ecosystem Assessment Program, says the abundance of cod and other finfish is controlled by a complex set of factors, and that increasing temperatures in the ecosystem make it essential to monitor the distribution of many species, some of them migratory and others not.

"A complex combination of factors influence ocean conditions, and it isn't always easy to understand the big picture when you are looking at one specific part of it at one specific point in time, "Fogarty said, a comparison similar to not seeing the forest when looking at a single tree in it. "We now have information from a variety of sources collected over a long period of time on the ecosystem, and are continually adding more data to clarify specific details. The data clearly show a relationship between all of these factors."

The 2012 spring plankton bloom, one of the longest duration and most intense in recent history, started at the earliest date recorded since the ocean color remote sensing data series began in 1998. In some locations, the spring bloom began in February, and was fully developed by March in all areas except Georges Bank, which had an average although variable spring bloom. The 2012 spring bloom in the Gulf of Maine began in early March, the earliest recorded bloom in that area.

"What this early start means for the Northeast Shelf ecosystem and its marine life is unknown," Fogarty said. "What is known is that things are changing, and we need to continue monitoring and adapting to these changes."

Intensive surveys of environmental conditions on the Northeast Shelf from Cape Hatteras, North Carolina to Nova Scotia were conducted from 1977 to 1987 as part of the Marine Resources Monitoring, Assessment & Prediction (MARMAP) program. The efforts continued at reduced levels through the 1990s and are ongoing today as part of the Center's Ecosystems Monitoring (EcoMon) program.

Plankton samples are collected six times a year in each of the four subareas of the Northeast Shelf: the Middle Atlantic Bight, Southern New England, Georges Bank, and the Gulf of Maine. EcoMon scientists also collect water samples and other oceanographic data about conditions during each season in each of the four areas to provide a long-term view of changing conditions on the Shelf.

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The above story is reprinted from materials provided by NOAA Fisheries Northeast Fisheries Science Center.

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19 Sep, 2012

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Global warming: Evolutionary straitjacket means flies can't take the heat

ScienceDaily (Sep. 17, 2012) — Many species of fruit fly lack the ability to adapt effectively to predicted increases in global temperatures and may face extinction in the near future, according to new research.

In a study published September 18 in Proceedings of the National Academy of Sciences, researchers from Monash University, The University of Melbourne and Danish collaborators showed that many species of fruit fly appear to be constrained within an evolutionary straitjacket and can't readily adapt to climate change-related temperature increases.

Dr Vanessa Kellermann from Monash University's School of Biological Sciences said current projections predict a 3ºC increase in mean annual temperature in the next century and even greater increases in extremes.

"Given our findings, these expected increases pose a major threat to biodiversity in the near future. Particularly as Drosophila or fruit fly findings are often more broadly applicable," Dr Kellermann said.

By examining nearly 100 species of fruit fly from around the world, the researchers showed that species had evolved to the temperature extremes and humidity of their environments. However, they had very little flexibility in being able to change their levels of heat resistance and seem unable to adapt to increased temperatures in the future.

High heat resistance is a feature of only some branches of the phylogeny -- the tree that shows how species are related through evolution -- of Drosophila. Other branches had very limited ability to change their levels of heat resistance; even when flies native to cooler areas grew up in a warm environment, their heat tolerance was not significantly altered.

"The problem is that only a handful of species have adapted to hot environments while most species have not and it seems very difficult to switch once you are stuck on a phylogenetic branch," Dr Kellermann said.

The researchers looked at species' prospects for dealing with projected temperature increases in the near future.

"If a species can only withstand temperatures of 36ºC and the maximum temperature of the environment is already 36ºC, an increase of even 1ºC would already put this species over the edge towards extinction," Dr Kellermann said.

Using this method, the researchers identified at-risk species and found that most tropical and mid-latitude species fell into this category.

"Without rapid adaptation, which now seems very unlikely, a lot of species may fall over under even a mild increase in temperature," Dr Kellermann said.

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The above story is reprinted from materials provided by Monash University.

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Journal Reference:

1. V. Kellermann, J. Overgaard, A. A. Hoffmann, C. Flojgaard, J.-C. Svenning, V. Loeschcke. Upper thermal limits of Drosophila are linked to species distributions and strongly constrained phylogenetically. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1207553109

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18 Sep, 2012

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Sorghum eyed as a southern bioenergy crop

ScienceDaily (Sep. 17, 2012) — Sweet sorghum is primarily grown in the United States as a source of sugar for syrup and molasses. But the sturdy grass has other attributes that could make it uniquely suited to production as a bioenergy crop, U.S. Department of Agriculture (USDA) studies suggest.

Sorghum is an ideal candidate because of its drought tolerance, adaptability to diverse growing conditions, low nitrogen fertilizer requirements, and high biomass (plant material) content, according to molecular biologist Scott Sattler and collaborator Jeff Pedersen with USDA's Agricultural Research Service (ARS). It also produces soluble sugar that can be converted to biofuel. Residual fibers left over from the juice extraction process also can be burned to generate electricity.

Sattler and Pedersen's studies of sorghum are part of a larger effort by ARS-USDA's principal intramural scientific research agency-to answer a government mandate calling for the production of up to 36 billion gallons of biofuel by 2022. Approximately 15 billion gallons of that total will come from grain ethanol, with the remaining 21 billion gallons to come from other sources, or "feedstocks," including sorghum, sugarcane, other grasses like switchgrass, and oilseed crops like rapeseed and soybean.

Sorghum and sugarcane are top candidates for production in the southeastern United States because they are complementary crops that can extend the biofuel production season and utilize the same equipment, note Sattler and Pedersen, who work at the ARS Grain, Forage and Bioenergy Research Unit in Lincoln, Neb. However, they are not the only team examining sweet sorghum's energy potential.

At the ARS Crop Genetics and Breeding Research Unit in Tifton, Ga., geneticist William Anderson and his colleagues are working to identify desirable sweet sorghum genes and their functions so improved varieties can be developed. In studies, they selected 117 genotypes from the ARS sorghum germplasm collection at Griffin, Ga., and evaluated them for their ability to mature quickly and resist fall armyworms and the fungal disease anthracnose.

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The above story is reprinted from materials provided by United States Department of Agriculture - Research, Education and Economics. The original article was written by Jan Suszkiw.

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18 Sep, 2012

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Assessing a new technique for ensuring fresh produce remains Salmonella-free

ScienceDaily (Sep. 17, 2012) — Researchers at the Institute of Food Research have tested a new technique to ensure fresh produce is free of bacterial contamination.

Plasmas are a mix of highly energetic particles created when gases are excited by an energy source. They can be used to destroy bacteria but as new research shows, some can hide from its effects in the microscopic surface structures of different foods.

Eating fresh fruit and vegetables is promoted as part of a healthy lifestyle, and consumers are responding to this by eating more and in a greater variety. Ensuring fruit and vegetables are free from contamination by food poisoning bacteria is crucial, as they are often eaten raw, without cooking or processing that kills off bacteria.

A move away from current chlorine-based decontamination is driving the search for new, safe ways of ensuring fresh fruit and vegetables are free from bacterial contamination without reducing quality or flavour. One technique being investigated is cold atmospheric gas plasma technology.

Plasmas can effectively inactivate microorganisms, and as they don't involve extreme conditions such as high temperature they have been suggested for use in decontaminating food surfaces without affecting the structure. Dr Arthur Thompson has been investigating how well cold atmospheric plasmas (CAP) inactivate Salmonella under different conditions and on different fresh produce foods at the Institute of Food Research, which is strategically funded by the Biotechnology and Biological Sciences Research Council.

Publishing in the journal Food Microbiology, Dr Thompson found Salmonella could be effectively inactivated by plasmas, but the length of exposure varied greatly depending on the type of produce. Other variables, such as the ambient temperature of the produce or the growth phase of the Salmonella had no significant effect. Inactivation on food surfaces took longer than on an artificial membrane filter surface.

To understand why, the researchers looked at the food surfaces with an electron microscope. At this microscopic level of detail, it was possible to see how Salmonella could 'hide' from the effects of the plasmas. Different structures, such as the bumps on the strawberries, the pores in lettuce leaves or the cell walls of potatoes create shadowed zones that block plasma reaching bacteria.

This study was conducted using a laboratory scale plasma device, used as part of ongoing research at IFR to study operational parameters and investigate precisely how cold plasma's destroy bacteria.

"The results suggest scaled up devices or combinations with other mild treatments could provide a very effective solution for destroying bacteria with little or no effect on the produce itself." said Dr Thompson. "What this study shows is that it will be important to take into account the type of food and its surface structure."

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Journal Reference:

1. A. Fernández, E. Noriega, A. Thompson. Inactivation of Salmonella enterica serovar Typhimurium on fresh produce by cold atmospheric gas plasma technology. Food Microbiology, 2012; DOI: 10.1016/j.fm.2012.08.007

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18 Sep, 2012

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How birds master courtship songs: Zebra finches shed light on brain circuits and learning

ScienceDaily (Sep. 17, 2012) — By studying how birds master songs used in courtship, scientists at Duke University have found that regions of the brain involved in planning and controlling complex vocal sequences may also be necessary for memorizing sounds that serve as models for vocal imitation.

In a paper appearing in the September 2012 issue of the journal Nature Neuroscience, researchers at Duke and Harvard universities observed the imitative vocal learning habits of male zebra finches to pinpoint which circuits in the birds' brains are necessary for learning their songs.

Knowing which brain circuits are involved in learning by imitation could have broader implications for diagnosing and treating human developmental disorders, the researchers said. The finding shows that the same circuitry used for vocal control also participates in auditory learning, raising the possibility that vocal circuits in our own brain also help encode auditory experience important to speech and language learning.

"Birds learn their songs early in life by listening to and memorizing the song of their parent or other adult bird tutor, in a process similar to how humans learn to speak," said Todd Roberts, Ph.D., the study's first author and postdoctoral associate in neurobiology at Duke University. "They shape their vocalizations to match or copy the tutor's song."

A young male zebra finch, Roberts said, learns his song in two phases -- memorization and practice. He said the pupil can rapidly memorize the song of an adult tutor, but may need to practice singing as many as 100,000 times in a 45-day period in order to accurately imitate the tutor's song.

During the study, voice recognition software was paired with optogenetics, a technology that combines genetics and optics to control the electrical activity of nerve cells, or neurons. Using these tools, the researchers were able to scramble brain signals coordinating small sets of neurons in the young bird's brain for a few hundred milliseconds while he was listening to his teacher, enabling them to test which brain regions were important during the learning process.

The study's results show that a song pre-motor region in the pupil's brain plays two different roles. Not only does it control the execution of learned vocal sequences, it also helps encode information when the pupil is listening to his tutor, Roberts said.

"We learn some of our most interesting behaviors, including language, speech and music, by listening to an appropriate model and then emulating this model through intensive practice," said senior author Richard Mooney, Ph.D., professor of neurobiology and member of the Duke Institute for Brain Sciences. "A traditional view is that this two-step sequence -- listening followed by motor rehearsal -- first involves activation by the model of brain regions important to auditory processing. This is followed days, weeks or even months later by activation of brain regions important to motor control."

"Here we found that a brain region that is essential to the motor control of song also has an essential role in helping in auditory learning of the tutor song," Mooney said. "This finding raises the possibility that the premotor circuits important to planning and controlling speech in our own brains also play an important role in auditory learning of speech sounds during early infancy." This brain region, known as Broca's area, is located in the frontal lobe of the left hemisphere.

The research has implications for the role of premotor circuits in the brain and suggests that these areas are important targets to consider when assessing developmental disorders that affect speech, language and other imitative behaviors in humans, Roberts said.

In addition to Roberts and Mooney, study authors include Sharon M. H. Gobes of Harvard University and Wellesley College; Malavika Murugan of Duke; and Bence P. Ölveczky of Harvard.

The research was supported by grants from the National Science Foundation and the National Institutes of Health (R01 DC02524) to Richard Mooney; and grants from NIH (R01 NS066408) and the Klingenstein, Sloan and McKnight Foundations to Bence P. Ölveczky; and a Rubicon fellowship from the Netherlands Organization for Scientific Research to Sharon M.H. Gobes.

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The above story is reprinted from materials provided by Duke University Medical Center, via EurekAlert!, a service of AAAS.

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Journal Reference:

1. Todd F Roberts, Sharon M H Gobes, Malavika Murugan, Bence P Ölveczky, Richard Mooney. Motor circuits are required to encode a sensory model for imitative learning. Nature Neuroscience, 2012; DOI: 10.1038/nn.3206

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

18 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_environment/~3/IIk0D0jpgi0/120917173101.htm
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Rapid urban expansion threatens biodiversity

ScienceDaily (Sep. 17, 2012) — A brief window of opportunity exists to shape the development of cities globally before a boom in infrastructure construction transforms urban land cover, according to a study in the Proceedings of the National Academy of Sciences.

Researchers at Yale, Texas A&M and Boston University predict that by 2030 urban areas will expand by more than 463,000 square miles, or 1.2 million square kilometers. That is equal to 20,000 American football fields becoming urban every day for the first three decades of this century.

The growth in urban areas will coincide with the construction of roads and buildings, water and sanitation facilities, and energy and transport systems that will transform land cover and cities globally. Recent estimates suggest that between $25 trillion and $30 trillion will be spent on infrastructure worldwide by 2030, with $100 billion a year in China alone.

"Given the long life and near irreversibility of infrastructure investments, it will be critical for current urbanization-related policies to consider their lasting impacts," said Karen Seto, lead author of the study and associate professor in the urban environment at the Yale School of Forestry & Environmental Studies. "We have a huge opportunity to shape how cities develop and their environmental impacts."

Nearly half of the increase in high-probability -- defined as greater than 75 percent -- urban expansion is forecasted to occur in Asia, with China and India absorbing 55 percent of the regional total. In China, urban expansion is expected to create a 1,100-mile coastal urban corridor from Hangzhou to Shenyang. In India, urban expansion will be clustered around seven state capital cities, with large areas of low-probability growth forecasted for the Himalaya region where many small villages and towns currently exist.

Africa's urban land cover will grow the fastest, at 590 percent above the 2000 level of 16,000 square miles. Urban expansion will be concentrated in that continent's five regions: the Nile River in Egypt; the coast of West Africa on the Gulf of Guinea; the northern shores of Lake Victoria in Kenya and Uganda and extending into Rwanda and Burundi; the Kano region in northern Nigeria; and greater Addis Ababa, Ethiopia.

"Urban expansion is concentrated in only a few areas where there are large cities and industry," said Seto. "From the northern shore of Lake Victoria down to Rwanda is also a major hotspot of urban expansion."

In North America, where 78 percent of the total population lives in urban areas, urban land cover will nearly double by 96,000 square miles by 2030. The study also forecasts that 48 of the 221 countries in the study will experience negligible amounts of urban expansion.

The researchers examined historical patterns of urban population growth and expansion, and used forecasts from the Intergovernmental Panel on Climate Change on gross domestic product and projections by the United Nations on urban population growth for their analysis.

Urban expansion will have significant impacts on biodiversity hotspots around the world. "We need to rethink conservation policies and what it means to be a sustainable city," said Burak Güneralp, the study's second author and research assistant professor at Texas A&M University. "It's not all about carbon footprint, which is what mayors and planners typically think about now, but we need to consider how urban expansion will have implications for other, nonhuman species and the value of these species for present and future generations."

Moreover, urban expansion will encroach on or destroy habitats for 139 amphibian species, 41 mammalian species and 25 bird species that are either on the Critically Endangered or Endangered Lists of the International Union for Conservation of Nature (IUCN). In addition, based on independent space-borne GLAS LiDAR measurements, the researchers estimate the aboveground, biomass carbon losses associated with land-clearing from new urban areas in the pan-tropics to be 5 percent of the tropical deforestation and land-use-change emissions.

"Urbanization is often considered a local issue, however our analysis shows that the direct impacts of future urban expansion on global biodiversity hotspots and carbon pools are significant," said Seto. "The world will experience an unprecedented era of urban expansion and city-building over the next few decades. The associated environmental and social challenges will be enormous, but so are the opportunities."

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The above story is reprinted from materials provided by Yale University.

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Journal Reference:

1. Karen C. Seto, Burak Güneralp and Lucy R. Hutyra. Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools. PNAS, 2012 DOI: 10.1073/pnas.1211658109

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18 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_environment/~3/2LT_2Pz2bGs/120917152040.htm
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Europe's second polar-orbiting weather satellite is aloft

ScienceDaily (Sep. 17, 2012) — The second Metop satellite was launched today (Sept. 17) from the Baikonur cosmodrome, in Kazakhstan, atop a Russian Soyuz launcher.

Metop-B will ensure the continuity of the weather and atmospheric monitoring service provided by its predecessor Metop-A, which has been circling the globe from pole to pole, 14 times a day, since 2006 and has now exceeded its design lifetime.

The Soyuz-Fregat vehicle lifted off at 16:28 GMT on Monday, Sept. 17. The Fregat upper stage manoeuvred to release the satellite into a polar orbit at an altitude of 810 km some 69 minutes later, over the Kerguelen Archipelago, in the Indian Ocean.

Metop-B, developed for EUMETSAT's polar satellite system, is now under the control of ESA's Operations Centre in Darmstadt, Germany.

In the coming days, its systems will be tested before it is handed over to EUMETSAT, also based in Darmstadt, for six months of commissioning of its payload before entering routine service with Metop-A.

For ESA's Director General Jean-Jacques Dordain: "The launch of this second Metop satellite has taken place about two and a half months after that of MSG-3; this is a perfect illustration of the vitality of Europe's weather satellite programmes developed in cooperation between ESA and EUMETSAT. The fact that the next generation satellites in line are already being prepared by ESA shows the strong commitment of Member States of both organisations to continue and improve collecting data that are supporting not only weather-forecasting but also monitoring and understanding of climate change. Such services are demonstrating daily the economical and societal value of investing in space infrastructure."

Volker Liebig, ESA's Director of Earth Observation Programmes, commented: "Metop-B will become operational while Metop-A is still active and performing well. This will ensure the continuity of the service without any risk of interruption in the data feed. Meanwhile, we are working with EUMETSAT to prepare the future with the second generation of European polar satellites."

Unlike the Meteosat satellites, which are watching about half of our planet from a fixed vantage point almost 36 000 km above the Gulf of Guinea, Metops work at lower altitude and fly over the whole globe to provide additional data on the atmosphere.

Beyond weather monitoring, the Metop and Meteosat satellites are part of ESA's effort on climate watch, which includes the experimental Earth Explorer satellites, to probe Earth and its atmosphere.

Three Earth Explorers have been launched since 2009 -- the GOCE gravity mapper, the SMOS water satellite and the CryoSat ice satellite -- and more are in preparation.

In 2013, ESA will start launching Sentinel satellites to monitor our environment and climate under the Global Monitoring for Environment & Security (GMES) initiative with the European Commission.

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18 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_environment/~3/Jr7nlHOWtDY/120917163149.htm
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New gene could lead to better bug-resistant plants

ScienceDaily (Sep. 17, 2012) — The discovery of a new gene could lead to better bug-resistant plants.

Research led by Michigan State University and appearing on the cover of this week's Proceedings of the National Academy of Sciences, demonstrates that domestic tomatoes could re-learn a thing or two from their wild cousins.

Long-term cultivation has led to tomato crops losing beneficial traits common to wild tomatoes. Anthony Schilmiller, MSU research assistant professor of biochemistry and molecular biology, was able to identify a gene that is involved in one of these beneficial traits.

Many tomato secrets are found in its hair. Trichomes, or hair-like protrusions, produce a mixture of specialized chemicals that shape the interactions between the plant and its environment. The location of the chemicals allows some of them to act as the first line of defense against pests.

One class of compounds, acyl sugars, is a frontline defender. Trichomes secrete acyl sugars to fend off pests. Schilmiller teamed with Robert Last, MSU professor of biochemistry and molecular biology, and Amanda Charbonneau, MSU doctoral researcher, to try to understand how these chemicals are made. Little was known about how acyl sugars were produced until now, and this research identifies and describes the first gene that participates in the production of the protective sugars in cultivated tomatoes, Schilmiller said.

"Acyl sugars play a critical role in allowing wild tomatoes to fend off bugs," he said. "Because cultivated tomatoes were not bred for their acyl sugar amounts and quality, they have reduced levels compared to wild ones we do not eat. Understanding how they are made is the first step toward breeding cultivated tomatoes, and other plants in this family, to make them more resistant to herbivores."

Other Solanaceous crops that could benefit from this research include potatoes, peppers, eggplants and petunias.

In addition, this work shows that the newly discovered gene is active only in one specific cell of one trichome type.

"Not only will we be able to potentially engineer heartier tomatoes, but understanding how to specifically target trichome gene expression without affecting the fruit, we'll also be able to add other important chemicals for insect resistance and possibly other beneficial traits to the surface of the plants," Schilmiller said.

The research was funded by the National Science Foundation.

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18 Sep, 2012

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Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_environment/~3/8JPFopyHoNM/120917161422.htm
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