Anatomically modern humans, Homo sapiens, first made their appearance in Africa during the Middle Stone Age which lasted from about 280,000 to 30,000 years ago.

Some of the earliest examples of human culture and technology are found in South Africa -- with fossil evidence of innovative spurts whose cause has left scientists puzzled.

The record reveals that a notable period of human advancement occurred about 71,500 years ago, and another between 64,000 and 59,000 years ago.

Examples of such innovation include the use of symbols, linked to the development of complex language, in engravings, the manufacture and use of stone tools and personal adornment with shell jewellery.

"We show for the first time that the timing of... these periods of innovation coincided with abrupt climate change," study co-author Martin Ziegler of the Cardiff University School of Earth and Ocean Sciences told AFP of the study in the journal Nature Communications.

"We found that South Africa experienced wetter conditions during these periods of cultural advance.

"At the same time, large parts of sub-Saharan Africa experienced drier conditions, so that South Africa potentially acted as a refugium for early humans."

Ziegler and a team reconstructed the South African climate over the past 100,000 years using a sediment core drilled out from the country's east coast.

The core shows changes in river discharge and rainfall.

"It offers for the first time the possibility to compare the archaeological record with a record of climate change over the same period and thus helps us to understand the origins of modern humans," Ziegler said by email.

Co-author Chris Stringer of London's Natural History Museum said the findings supported the view that population growth fuelled cultural advancement through increased human interactions.

"Such climate-driven pulses in southern Africa and more widely were probably fundamental to the origin of key elements of modern human behaviour in Africa and to the subsequent dispersal of Homo sapiens from its ancestral homeland," concluded the study.

]]> Thu, 23 MAY 2013 23:05:41 AEST Melbourne, Australia (SPX) May 22, 2013 - Salamanders' immune systems are key to their remarkable ability to regrow limbs, and could also underpin their ability to regenerate spinal cords, brain tissue and even parts of their hearts, scientists have found.

In research published in the Proceedings of the National Academy of Sciences researchers from the Australian Regenerative Medicine Institute (ARMI) at Monash University found that when immune cells known as macrophages were systemically removed, salamanders lost their ability to regenerate a limb and instead formed scar tissue.

Lead researcher, Dr James Godwin said the findings brought researchers a step closer to understanding what conditions were needed for regeneration.

"Previously, we thought that macrophages were negative for regeneration, and this research shows that that's not the case - if the macrophages are not present in the early phases of healing, regeneration does not occur," Dr Godwin said.

"Now, we need to find out exactly how these macrophages are contributing to regeneration. Down the road, this could lead to therapies that tweak the human immune system down a more regenerative pathway."

Salamanders deal with injury in a remarkable way. The end result is the complete functional restoration of any tissue, on any part of the body including organs. The regenerated tissue is scar free and almost perfectly replicates the injury site before damage occurred.

"We can look to salamanders as a template of what perfect regeneration looks like," Dr Godwin said.

Aside from "holy grail" applications, such as healing spinal cord and brain injuries, Dr Godwin believes that studying the healing processes of salamanders could lead to new treatments for a number of common conditions, such as heart and liver diseases, which are linked to fibrosis or scarring. Promotion of scar-free healing would also dramatically improve patients' recovery following surgery.

There are indications that there is the capacity for regeneration in a range of animal species, but it has, in most cases been turned off by evolution.

"Some of these regenerative pathways may still be open to us. We may be able to turn up the volume on some of these processes," Dr Godwin said.

"We need to know exactly what salamanders do and how they do it well, so we can reverse-engineer that into human therapies."

]]> Thu, 23 MAY 2013 23:05:41 AEST Durham UK (SPX) May 21, 2013 - Human intelligence cannot be explained by the size of the brain's frontal lobes, say researchers. Research into the comparative size of the frontal lobes in humans and other species has determined that they are not - as previously thought - disproportionately enlarged relative to other areas of the brain, according to the most accurate and conclusive study of this area of the brain.

It concludes that the size of our frontal lobes cannot solely account for humans' superior cognitive abilities.

The study by Durham and Reading universities suggests that supposedly more 'primitive' areas, such as the cerebellum, were equally important in the expansion of the human brain. These areas may therefore play unexpectedly important roles in human cognition and its disorders, such as autism and dyslexia, say the researchers.

The study is published in the Proceedings of the National Academy of Sciences (PNAS).

The frontal lobes are an area in the brain of mammals located at the front of each cerebral hemisphere, and are thought to be critical for advanced intelligence.

Lead author Professor Robert Barton from the Department of Anthropology at Durham University, said: "Probably the most widespread assumption about how the human brain evolved is that size increase was concentrated in the frontal lobes.

"It has been thought that frontal lobe expansion was particularly crucial to the development of modern human behaviour, thought and language, and that it is our bulging frontal lobes that truly make us human. We show that this is untrue: human frontal lobes are exactly the size expected for a non-human brain scaled up to human size.

"This means that areas traditionally considered to be more primitive were just as important during our evolution. These other areas should now get more attention. In fact there is already some evidence that damage to the cerebellum, for example, is a factor in disorders such as autism and dyslexia."

The scientists argue that many of our high-level abilities are carried out by more extensive brain networks linking many different areas of the brain. They suggest it may be the structure of these extended networks more than the size of any isolated brain region that is critical for cognitive functioning.

Previously, various studies have been conducted to try and establish whether humans' frontal lobes are disproportionately enlarged compared to their size in other primates such as apes and monkeys. They have resulted in a confused picture with use of different methods and measurements leading to inconsistent findings.

The Durham and Reading researchers, funded by The Leverhulme Trust, analysed data sets from previous animal and human studies using phylogenetic, or 'evolutionary family tree', methods, and found consistent results across all their data. They used a new method to look at the speed with which evolutionary change occurred, concluding that the frontal lobes did not evolve especially fast along the human lineage after it split from the chimpanzee lineage.

]]> Thu, 23 MAY 2013 23:05:41 AEST Cancun, Mexico (SPX) May 16, 2013 - It's very hard to convict a murderer if the victim's body can't be found. And the best way to hide a body is to bury it. Developing new tools to find those clandestine graves is the goal of a small community of researchers spread across several countries, some of whom are presenting their work on Tuesday, May 14, at the Meeting of the Americas in Cancun, Mexico, a scientific conference organized and co-sponsored by the American Geophysical Union.

"Nowadays, there are thousands of missing people around the world that could have been tortured and killed and buried in clandestine graves," said Jamie Pringle, lecturer in geoscience at the School of Physical Sciences and Geography at Keele University in the U.K. "This is a huge problem for their families and governments that are responsible for the human rights for everybody. These people need to be found and the related crime cases need to be resolved."

Mostly, people throw resources at the search for clandestine graves and try to see what works best, said Pringle. But he and his colleagues Carlos Molina and Orlando Hernandez of the National University of Colombia in Bogota are among those trying to refine the techniques for finding mass graves, so that eventually there might be a reliable toolkit for not only finding bodies, but discovering details like the time of deaths and burials--all critical evidence for convicting murderers.

Previous studies on which Pringle has worked have involved simulated clandestine graves in the U.K. in which they buried pigs and then monitored soil gases, fluids and other physical changes over time.

That research made it clear how much the detection of graves depends on understanding how corpses change in different soils and climates. This is being applied to active forensic cases throughout Europe.

International collaborations among forensic geophysicists have already proved helpful in cases such as the so-called IRA 'Disappeared' victims found on beaches in Northern Ireland and current work underway to detect Civil War mass graves in Spain.

In the latest project, being presented in a poster at the Cancun meeting, the researchers propose to bury pigs in eight different simulated clandestine mass grave scenarios in different soils and climates in Colombia.

Then they will study the mass graves with geophysical methods like ground penetrating radar, electrical resistivity, conductivity and magnetometry among others. Their plan is to survey the graves every eight days during the first month, 15 days in the second and third months, and monthly until 18 months have passed.

The data they collect will be used to map the mass graves and compare them, adjusting for site variables like soil type and rainfall. They also expect to compare their results with other studies and forensic cases.

"The project's integrated geophysical survey results will support the search for mass graves and thus help find missing people, bring perpetrators to justice and provide closure for families," said Molina.

]]> Thu, 23 MAY 2013 23:05:41 AEST Oxford, England (UPI) May 16, 2013 - Stimulation applied to a brain area known to be important for math ability has been shown to improve the ability to manipulate numbers, British researchers say.

"With just five days of cognitive training and noninvasive, painless brain stimulation, we were able to bring about long-lasting improvements in cognitive and brain functions," Roi Cohen Kadosh of the University of Oxford reported in the journal Current Biology.

While the researchers acknowledge no one knows exactly how the relatively new technique -- transcranial random noise stimulation -- works, they say the evidence suggests it allows the brain to work more efficiently by making neurons fire more synchronously.

The technique improves mental arithmetic -- the ability to add, subtract or multiply a string of numbers in one's head, for example -- not just new number learning, the researchers said.

Mental arithmetic is a more complex and challenging task, which more than 20 percent of people struggle with, they said.

The stimulation technique could be of particular help to those suffering with neurodegenerative illness, stroke or learning difficulties, Cohen Kadosh said.

"Math is a highly complex cognitive faculty that is based on a myriad of different abilities," he said. "If we can enhance mathematics, therefore, there is a good chance that we will be able to enhance simpler cognitive functions."

]]> Thu, 23 MAY 2013 23:05:41 AEST Tysons Corner, Virginia (AFP) May 16, 2013 - When Dexter the cocker spaniel tore a ligament in his hind leg a few weeks ago, he didn't suffer in silence. Instead, his owner blogged about.

"The vet told me my dog needed surgery, and I thought, 'You know, there's got to be something else'," said Carol Bryant, who writes a "canine-centric online magazine" called A Fidose of Reality.

Responding to her blog entries, readers told Bryant that Dexter didn't have to go under the knife. He had options, like laser therapy and a leg brace he'll be wearing for the next six months.

So good is his progress that Dexter has come with Bryant from rural Pennsylvania to this Washington suburb for the biggest US gathering ever of pet bloggers -- people who embrace social media to rave about pets.

The Fifth Annual BlogPaws Conference, with 500 participants and perhaps as many critters, is a chance to network, swap ideas and maybe win a coveted Nose-to-Nose Pet Blogging and Social Media award (for which The Intrepid Pup, about a peripatetic Vizsla called Tavish, is nominated in three categories).

Workshops include a primer on using Google Analytics to gauge online readership, building bridges between bloggers and veterinarians, and Schmitty the Weather Dog demonstrating a just-released Sony canine video harness.

In its online community, BlogPaws has 2,200 members, said co-founder Yvonne DiVita, who writes about her cat and three dogs in Colorado on a blog titled Scratchings and Sniffings.

"I would guess we're going to hit close to 3,000 by the end of the year," she told AFP as bloggers (predominantly female) and their pets (predominantly dogs) took over the lobby of the Sheraton hotel on Thursday.

With Americans spending $53.33 billion on their pets last year, according to the American Pet Products Association, and 62 percent of households owning a pet, the pet care industry is taking the bloggers seriously.

In an exhibition hall, big hitters like pet food maker Nestle Purina rub shoulders with upstarts like the Spoiled Pup Boutique, a New York area canine couturier, wooing bloggers to test and endorse their products.

"The followers and readers of pet blogs are so loyal, and they trust the word of bloggers," said Bridget Evans, a San Diego publicist attending BlogPaws for VetIQ, a newcomer to the pet medication and health supplements business.

It's come to the point, DiVita said, where some popular bloggers with solid track records and substantial followings can give up their day jobs and earn a good middle-class income -- or better -- through online advertising.

"I know bloggers that are making upwards of six figures," she said, while others are content with just a few hundred dollars.

"We're kind of the rock stars of the pet industry," added Bryant, who cautions that the key to blogging success is finding a unique voice and then keeping it real: "You need to be yourself when you blog."

Longtime syndicated pet columnist Steve Dale said his blog, which he updates daily, is one of the most popular among 200 blogs hosted by the Chicago Tribune's Chicago Now website, attracting 100,000 visitors a month.

"It's pretty incredible that a pet blog would be among the top 20 ... and here's my secret: I have no idea what I'm doing," Dale, the owner of two mutts, a cat and a northern blue-tongued skink lizard, told AFP.

Actually, he does have an idea: blogging enables Dale to cover breaking pet news ("In the pet world, there is news, believe it or not") like a pet food recall that otherwise wouldn't make his twice-weekly print column My Pet World.

"It can be anything, and bingo! bongo! I can cover it," he said.

A keynote speaker at BlogPaws, Dale is keen to draw fellow bloggers' attention to some worrying pet health trends: fewer pets getting check-ups at the vets, for instance, and upticks in flea infestations and heartworm.

From San Francisco, Julia Gleason hopes her year-old fashion-meets-Fido blog Canines and Couture, which often features her English bulldog, will grow to a stage where she bid farewell to her day job at a legal consultancy.

"I have lofty goals to turn it into an actual business at some point," she told AFP as Chilly, a white poodle with a dyed purple head and tail, chilled out on the floor by the wine bar.

"Right now, I'm focusing on building my audience and building a following."

]]> Thu, 23 MAY 2013 23:05:41 AEST Los Angeles (UPI) May 16, 2013 - When the brain's primary "learning center" is damaged it can rewire itself, creating new neural circuits to compensate for lost functions, U.S. researchers say.

Scientists at UCLA, working with colleagues in Australia, say they've been able to pinpoint the regions of the brain involved in creating those alternate pathways, which are often far from the damaged site.

The finding that parts of the prefrontal cortex can take over when the hippocampus, the brain's key center of learning and memory formation, is disabled -- dubbed neural-circuit plasticity -- could potentially help scientists develop new treatments for Alzheimer's disease, stroke and other conditions involving damage to the brain, a UCLA release said Thursday.

Laboratory experiments with rats identified significant functional changes in two specific regions of the prefrontal cortex after damage to the hippocampus.

"Interestingly, previous studies had shown that these prefrontal cortex regions also light up in the brains of Alzheimer's patients, suggesting that similar compensatory circuits develop in people," neuroscience researcher Bruce Vissel of the Garvan Institute of Medical Research in Sydney said.

"While it's probable that the brains of Alzheimer's sufferers are already compensating for damage, this discovery has significant potential for extending that compensation and improving the lives of many."

The hippocampus, which plays critical roles in processing, storing and recalling information, is highly susceptible to damage through stroke or lack of oxygen and is critically involved in Alzheimer's disease, UCLA's Michael Fanselow said.

"Until now, we've been trying to figure out how to stimulate repair within the hippocampus," he said. "Now we can see other structures stepping in and whole new brain circuits coming into being."

]]> Thu, 23 MAY 2013 23:05:41 AEST Durham, England (UPI) May 15, 2013 - Human intelligence can no longer be explained as just the evolutionary increase in the size of the brain's frontal lobes, British researchers say.

A study by Durham and Reading universities into the comparative size of the frontal lobes in humans and other species has determined that they aren't, as previously believed, disproportionately enlarged relative to other areas of the brain, a Durham release reported Wednesday.

Therefore the size of frontal lobes cannot solely account for humans' superior cognitive abilities, the researchers said; supposedly more "primitive" areas, such as the cerebellum, were equally important in the expansion of the human brain.

These areas may therefore play previously unsuspected roles in human cognition and its disorders such as autism and dyslexia, they said.

"Probably the most widespread assumption about how the human brain evolved is that size increase was concentrated in the frontal lobes," Durham anthropologist Robert Baron said.

"It has been thought that frontal lobe expansion was particularly crucial to the development of modern human behavior, thought and language and that it is our bulging frontal lobes that truly make us human," he said.

"We show that this is untrue: human frontal lobes are exactly the size expected for a non-human brain scaled up to human size."

Many high-level cognitive abilities are carried out by more extensive networks linking many different areas of the brain, the researchers argue, suggesting the structure of these networks -- more than the size of any particular brain region -- is critical for cognitive functioning.

]]> Thu, 23 MAY 2013 23:05:41 AEST Southampton, UK (SPX) May 14, 2013 - A University of Southampton professor has carried out the most detailed analysis ever of the archaeological remains of the lost medieval town of Dunwich, dubbed 'Britain's Atlantis'.

Funded and supported by English Heritage, and using advanced underwater imaging techniques, the project led by Professor David Sear of Geography and Environment has produced the most accurate map to date of the town's streets, boundaries and major buildings, and revealed new ruins on the seabed.

Professor Sear worked with a team from the University's GeoData Institute; the National Oceanography Centre, Southampton; Wessex Archaeology; and local divers from North Sea Recovery and Learn Scuba.

He comments, "Visibility under the water at Dunwich is very poor due to the muddy water. This has limited the exploration of the site.

"We have now dived on the site using high resolution DIDSON acoustic imaging to examine the ruins on the seabed - a first use of this technology for non-wreck marine archaeology.

"DIDSON technology is rather like shining a torch onto the seabed, only using sound instead of light. The data produced helps us to not only see the ruins, but also understand more about how they interact with the tidal currents and sea bed."

Peter Murphy, English Heritage's coastal survey expert who is currently completing a national assessment of coastal heritage assets in England, says: "The loss of most of the medieval town of Dunwich over the last few hundred years - one of the most important English ports in the Middle Ages - is part of a long process that is likely to result in more losses in the future. Everyone was surprised, though, by how much of the eroded town still survives under the sea and is identifiable.

"Whilst we cannot stop the forces of nature, we can ensure what is significant is recorded and our knowledge and memory of a place doesn't get lost forever. Professor Sear and his team have developed techniques that will be valuable to understanding submerged and eroded terrestrial sites elsewhere."

Present day Dunwich is a village 14 miles south of Lowestoft in Suffolk, but it was once a thriving port - similar in size to 14th Century London. Extreme storms forced coastal erosion and flooding that have almost completely wiped out this once prosperous town over the past seven centuries. This process began in 1286 when a huge storm swept much of the settlement into the sea and silted up the Dunwich River.

This storm was followed by a succession of others that silted up the harbour and squeezed the economic life out of the town, leading to its eventual demise as a major international port in the 15th Century. It now lies collapsed and in ruins in a watery grave, three to 10 metres below the surface of the sea, just off the present coastline.

The project to survey the underwater ruins of Dunwich, the world's largest medieval underwater town site, began in 2008. Six additional ruins on the seabed and 74 potential archaeological sites on the seafloor have since been found.

Combining all known archaeological data from the site, together with old charts and navigation guides to the coast, it has also led to the production of the most accurate and detailed map of the street layout and position of buildings, including the town's eight churches. Findings highlights are:

+ Identification of the limits of the town, which reveal it was a substantial urban centre occupying approximately 1.8 km2 - almost as large as the City of London

+ Confirmation the town had a central area enclosed by a defensive, possibly Saxon earthwork, about 1km2

+ The documentation of ten buildings of medieval Dunwich, within this enclosed area, including the location and probable ruins of Blackfriars Friary, St Peter's, All Saint's and St Nicholas Churches, and the Chapel of St Katherine

+ Additional ruins which initial interpretation suggests are part of a large house, possibly the town hall

+ Further evidence that suggests the northern area of the town was largely commercial, with wooden structures associated with the port

+ The use of shoreline change analysis to predict where the coastline was located at the height of the town's prosperity

Commenting on the significance of Dunwich, Professor Sear says: "It is a sobering example of the relentless force of nature on our island coastline. It starkly demonstrates how rapidly the coast can change, even when protected by its inhabitants.

"Global climate change has made coastal erosion a topical issue in the 21st Century, but Dunwich demonstrates that it has happened before. The severe storms of the 13th and 14th Centuries coincided with a period of climate change, turning the warmer medieval climatic optimum into what we call the Little Ice Age.

"Our coastlines have always been changing, and communities have struggled to live with this change. Dunwich reminds us that it is not only the big storms and their frequency - coming one after another, that drives erosion and flooding, but also the social and economic decisions communities make at the coast. In the end, with the harbour silting up, the town partly destroyed, and falling market incomes, many people simply gave up on Dunwich."

]]> Thu, 23 MAY 2013 23:05:41 AEST London, UK (SPX) May 10, 2013 - From Ireland to the Balkans, Europeans are all closely related according to a new study of the DNA of people from across the continent. The study, conducted by Graham Coop at the University of California, Davis, and Peter Ralph of the University of Southern California, examined relatedness among Europeans up to about 3,000 years ago, comparing genetic sequences from over 2,000 individuals. Their results are published in the open access journal PLOS Biology.

The researchers found that the extent to which two people are related tends to be smaller the farther apart they live, as one might expect. However, even two individuals as far apart as the UK and Turkey are still likely to share all of each other's ancestors from only a thousand years ago.

"What's remarkable about this is how closely everyone is related to each other," said Graham Coop, Professor of Evolution and Ecology at UC Davis. "On a genealogical level, everyone in Europe traces back to nearly the same set of ancestors within a thousand years.

"This was predicted by theory over a decade ago, and we now have concrete evidence from DNA data." Although the data was from Europeans, the same pattern is likely to apply to the rest of the world as well, he added.

"Imposed on top of this high level of relatedness are subtle local trends that probably mark demographic shifts and historic migrations," Ralph noted. "Barriers like mountain ranges or linguistic differences have also had the effect of slightly reducing relatedness between regions."

"There are lots of tantalizing hints at history," he explained. For example, although the differences are relatively small, Italians tend to have a lower level of relatedness to each other, and to other Europeans, perhaps resulting from the long history of many distinct cultures within the peninsula.

Also, many eastern Europeans showed subtly higher levels of relatedness, possibly influenced by the expansion of Slavic peoples into Europe over a thousand years ago.

To learn about these patterns, Ralph and Coop used ideas about the expected amount of shared genome between relatives of varying degrees of relatedness. For example, first cousins have grandparents in common and share long stretches of DNA. Ralph and Coop looked for shorter blocks of DNA that were shared between cousins separated by many more generations.

Because the number of ancestors doubles with every generation, the chance of having identical DNA in common with more distant relatives quickly drops, but in large samples, rare cases of distant sharing could be detected.

With their analysis, Coop and Ralph were able to detect these blocks of DNA in common between different individuals spread across Europe, and calculate how long ago they shared an ancestor.

The authors hope to continue the work with larger and more detailed databases, including much finer resolution data on individuals from regions within countries.

However, Coop noted that while studies of genetic ancestry can be informative about history, they do not tell the whole story. Archaeology and linguistics can tell us much more about how cultures and societies moved and changed-but in turn cannot always inform us about the movement of people, since people can learn a new language or a new cultural practice whatever their ancestry.

"These studies need to proceed hand in hand, to form a much fuller picture of history over the past thousands of years," Coop said.

Ralph P, Coop G (2013) The Geography of Recent Genetic Ancestry across Europe. PLoS Biol 11(5): e1001555. doi:10.1371/journal.pbio.1001555 FAQ PAGE

]]> Thu, 23 MAY 2013 23:05:41 AEST Subscribe to our daily selection of space, military, environment and energy newsletters responseText http://visitor.constantcontact.com/manage/optin/ea?v=0016gbbKsaiGSpQFojVO8ZoHw%3D%3D