Volunteers, Home Computers Help Identify Gamma Ray Pulsars

Posted November 26th, 2013 at 5:45 pm (UTC+0)
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A gamma-ray pulsar is a compact neutron star that accelerates charged particles to speeds that are described only by the theory of relativity in a strong magentic field. The process produces gamma radiation seen in violet. (© NASA/Fermi/Cruz de Wilde)

A gamma-ray pulsar is a compact neutron star that accelerates charged particles to speeds that are described only by the theory of relativity in a strong magnetic field. The process produces gamma radiation seen in violet. (NASA/Cruz de Wilde)

A network of 40,000 volunteer researchers, along with 200,000 personal computers worldwide, has helped scientists from the Max Planck Institutes for Gravitational Physics and Radio Astronomy – the Albert Einstein Institute (AEI) discover four gamma-ray pulsars.

Pulsars are compact and rapidly rotating neutron stars which are the remains of stars that have exploded.

The discoveries made by this unique collaboration were made possible by an online computing project called Einstein@Home, which was launched back in 2005 as a joint program from the Center for Gravitation and Cosmology at the University of Wisconsin-Milwaukee and the AEI in Hannover, Germany.

The volunteers were from countries such as Australia, Canada, France, Germany, Japan and the USA, and used data from NASA’s Fermi Gamma-Ray Space Telescope, according to the AEI.

“Our innovative solution for the compute intensive search for gamma-ray pulsars is the combination of particularly efficient methods along with the distributed computing power of Einstein@Home,” said AEI’s Holger Pletsch, who’s also the lead author of the study. “The volunteers from around the world enable us to deal with the huge computational challenge posed by the Fermi data analysis. In this way, they provide an invaluable service to astronomy.”

The online computer project connects 200,000 home and office computers to a global supercomputer.  Since identifying these new gamma-ray pulsars requires a lot of computing power, the combined computing ability provided by the Einstein@Home network of personal computers, along with the supercomputer, provides scientists with an efficient yet more cost effective way to conduct their research.

A neutron star is the densest object astronomers can observe directly, crushing half a million times Earth's mass into a sphere about 20 kilometers across. This illustration compares the size of a neutron star to the area around Hannover, Germany (© NASA's Goddard Space Flight Center)

A neutron star is the densest object astronomers can observe directly, crushing half a million times Earth’s mass into a sphere about 20 kilometers across. This illustration compares the size of a neutron star to the area around Hanover, Germany (NASA)

“The first-time discovery of gamma-ray pulsars by Einstein@Home is a milestone – not only for us but also for our project volunteers. It shows that everyone with a computer can contribute to cutting-edge science and make astronomical discoveries,” said Bruce Allen from AEI and the principal investigator of Einstein@Home. “I’m hoping that our enthusiasm will inspire more people to help us with making further discoveries.”

Pulsars have usually been detected by the beam of electromagnetic radiation or radio waves they emit when the signal points toward Earth. But, according to AEI officials, the four pulsars discovered through this collaborative effort are only visible in gamma-rays and not radio waves.

AEI officials said special follow-up observations of all four new pulsar discoveries will be conducted with radio telescopes located at Germany’s Max Planck Institute for Radio Astronomy and the Parkes Observatory in Australia.  Scientists hope these observations will confirm that radio waves won’t be detected in the pulsars.

Data gathered by the Fermi Gamma-Ray Space Telescope, which was launched from the Cape Canaveral Air Force Base on June 11, 2008 is also credited with helping scientists to discover thousands of gamma-ray sources that they said had been previously unknown.   According to AEI those gamma-ray sources may also include hundreds of yet undiscovered pulsars.

The Sun is About to Flip Its (Magnetic) Poles

Posted November 15th, 2013 at 9:37 pm (UTC+0)
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The Sun photographed by the Atmospheric Imaging Assembly (AIA 304) of NASA's Solar Dynamics Observatory (SDO). This is a false-color image of the Sun observed in the extreme ultraviolet region of the spectrum. (NASA/SDO (AIA))

The Sun photographed by NASA’s Solar Dynamics Observatory (SDO). (NASA/SDO (AIA))

Here at Science World, one of our favorite topics is the sun. We’ve been able to provide you with a number of informational pieces regarding events and phenomena such as the ebb and flow of the sun’s activity throughout its roughly 11 year solar cycle.

As the sun goes through this process – from when it’s least active (solar minimum) to its most active (solar maximum) and back again – it undergoes what scientists describe as a “complete makeover” when its magnetic field reverses or flips its polarity.  The sun’s magnetic north becomes its south and vice versa, causing effects that can ripple throughout our solar system.

Scientists say that our sun, which is nearing the peak of its current solar cycle, is about to flip its magnetic poles. The current solar cycle that began in 2008 or 2009 is the 24th since scientists started tracking them back in 1755.  Compared to previous solar cycles, researchers have said that the current cycle appears to be weaker than any other before it, perhaps the weakest in 100 years.

While not much is known about the actual mechanics behind this polarity flip, solar scientists at Stanford University’s Wilcox Solar Observatory are keeping an eye on the sun’s magnetic field, monitoring and measuring it every day, as they have done since 1975.

Large field-of-view image of sunspots. The image has been colored yellow for aesthetic reasons. (Royal Swedish Academy of Sciences)

Large field-of-view image of sunspots. The image has been colored yellow for aesthetic reasons. (Royal Swedish Academy of Sciences)

The daily monitoring efforts allow these researchers to observe and identify the magnetic polarity reversal as it actually takes place on the sun’s surface.  This upcoming shift in the Sun’s poles will be the fourth the observatory has watched.

While we laypeople tend to label the sun’s magnetic poles as north and south, Todd Hoeksema, a solar physicist and Director of the Wilcox Solar Observatory, suggests that we think of the poles as positive and negative. “It’s best not to think of it like a big bar magnet.  That works OK for Earth but not the Sun.  Think of the Sun as having a large number of smaller magnetic fields scattered over the surface,” he said.

Of course, hearing that the sun is about undergo a significant event like a pole reversal can alarm some people who may wonder if they might be in danger.  But, according to Hoeksema we have nothing to worry about.

“When it happened about eleven or twelve years ago, you probably didn’t even notice,” he said.

Hoeksema explains that the pole reversal process takes place over time throughout the solar cycle where sunspots come up at the Sun’s mid-latitudes (equator) and spread out toward its poles.  Gradually, as the magnetic flux (a measurement of the quantity of magnetism) that comes up with the sunspots moves pole-ward it erodes the existing polar fields and replaces them with magnetic fields that have the opposite polarity.

Illustration of the sun's magnetic field lines extending out (NASA/SVS)

Illustration of the sun’s magnetic field lines extending out (NASA/SVS)

“What we’re seeing recently is more activity in the (sun’s) southern hemisphere and that’s the pole that’s just about to switch or is switching right now,” said Hoeksema.

He also pointed out that the sun’s northern pole switched about a year ago in the summer of 2012.

The sun’s two hemispheres (north and south) aren’t in perfect synchronization with each other and the number of sunspots that emerge in each of the hemispheres can be different.

Because of this, according to Hoeksema, the sun’s ‘new’ polarity that moves poleward is generally different in the north and south in both timing and strength which causes one geographic pole to change its magnetic field direction before the other.

Since it is at or near its peak of activity, the sun is has been pumping out a lot of energy particles throughout the solar system via the solar wind. Because of this outpouring of sun particles, according to Hoeksema, we’re actually being shielded from the high energy particles that come at us from other parts of the galaxy.

Todd Hoeksema from Stanford University monitors the sun's magnetic field at Stanford's Wilcox Solar Observatory. (Photo: Linda A. Cicero /Stanford News Service)

Todd Hoeksema from Stanford University monitors the sun’s magnetic field at Stanford’s Wilcox Solar Observatory. (Photo: Linda A. Cicero /Stanford News Service)

Along with their ground-based Wilcox Solar Observatory at Stanford, Hoeksema and his fellow scientists also use some sophisticated observational tools in space, too.  One is as an instrument aboard NASA’s Solar Dynamic Observatory (SDO) called the ‘Helioseismic and Magnetic Imager’ (HMI) which allows the team to measure the sun’s magnetic field every 45 seconds.

These measurements help scientists zero in on where and what kind of solar activity is taking place on the Sun, something that Hoeksema and his colleagues hope will help scientists better predict potentially dangerous space weather.

Dr. Todd Hoeksema joins us this weekend on the radio edition of “Science World.”  To listen to our conversation either tune into the show (see right column for scheduled times) or check out the interview below.

Also check out the video below.

Solar physicist Todd Hoekserma explains sun’s magnetic reversal (Stanford University)

Global Precipitation Changes Linked to Human-induced Climate Change

Posted November 12th, 2013 at 7:43 pm (UTC+0)
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A rainy day in Chicago (Bernt Rostad via Flickr/Creative Commons)

A rainy day in Chicago (Bernt Rostad via Flickr/Creative Commons)

A new study shows changes in precipitation are affected by human activities and can’t be explained by natural phenomena, such as El Niños and La Niñas.

Scientists from the Lawrence Livermore National Laboratory in California published the study in the Proceedings of the National Academy of Sciences.

The researchers suggest two mechanisms will probably cause changes in the distribution and intensity of precipitation worldwide because of human release of greenhouse gases that trap heat and deplete the ozone.

First, there are some thermodynamic changes, caused by the increasing global temperatures, which will likely result in already wet regions of the world getting wetter while the dry areas will become drier.

The researchers also think increased temperatures could change global atmospheric circulation patterns – movement of air at all levels of the atmosphere – which might move storm tracks and push current subtropical dry zones toward the poles.

“Both these changes are occurring simultaneously in global precipitation and this behavior cannot be explained by natural variability alone,” said Kate Marvel, the study’s lead author. “External influences such as the increase in greenhouse gases are responsible for the changes.”

To reach their conclusions, the researchers compared various climate model predictions with global observations from 1979-2012 that were provided by the Global Precipitation Climatology Project.

(Flóra Soós via Flickr/Creative Commons)

(Flóra Soós via Flickr/Creative Commons)

The scientists found natural climate phenomena alone couldn’t explain the ongoing changes in global precipitation patterns. They also noted that any fluctuations in climate brought on by natural causes could either intensify or shift precipitation towards the poles, but it’s very rare for both to take place together naturally.

“In combination, man-made increases in greenhouse gases and stratospheric ozone depletion are expected to lead to both an intensification and redistribution of global precipitation,” said Céline Bonfils, another co-author of the study. “The fact that we see both of these effects simultaneously in the observations is strong evidence that humans are affecting global precipitation.”

The researchers said their studies helped them identify a “fingerprint pattern” that can explain the simultaneous changes in precipitation locations and intensity brought on by external forces such as warming caused by human activities.

“We have shown that the changes observed in the satellite era are externally forced and likely to be from man,” Bonfils said.

Science Images

Posted November 8th, 2013 at 6:00 pm (UTC+0)
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This is a magnification of a nerve cell. The green fibrous material surrounding the yellow core are the branches of the cell. Scientists recently were able to identify a chain reaction that allows the cell to repair of these branches when they are severed. (Yongcheol Cho, PhD)

This is a magnification of a nerve cell. The green fibrous material surrounding the yellow core are the branches of the cell. Scientists recently were able to identify a chain reaction that allows the cell to repair of these branches when they are severed. (Yongcheol Cho, PhD)

This hybrid image of the Boomerang nebula, called the “coldest place in the universe”, was taken with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope and the Hubble Space Telescope. The red in the image are cold gas molecules. (NRAO/AUI/NSF/NASA/STScI/JPL-Caltech)

This hybrid image of the Boomerang nebula, called the “coldest place in the universe”, was taken with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope and the Hubble Space Telescope. The red in the image are cold gas molecules. (NRAO/AUI/NSF/NASA/STScI/JPL-Caltech)

The Heterospilus is one 277 new wasp species that was recently found in Costa Rica by researchers from the University of Illinois at Urbana-Champaign. This image shows a female of the Heterospilus species. (Alexander Wild)

The Heterospilus is one 277 new wasp species that was recently found in Costa Rica by researchers from the University of Illinois at Urbana-Champaign. This image shows a female of the Heterospilus species. (Alexander Wild)

Scientists recently discovered a rocky exoplanet called Kepler-78B that orbits its star every eight and a half hours at a distance of less than 1,609,344 km. This is an artist’s conception of that scorching hot lava world. According to current theories of planet formation, it couldn't have formed so close to its star, nor could it have moved there. (David A. Aguilar/CfA)

Scientists recently discovered a rocky exoplanet called Kepler-78B that orbits its star every eight and a half hours at a distance of less than 1,609,344 km. This is an artist’s conception of that scorching hot lava world. According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there. (David A. Aguilar/CfA)

Recent testing of a new climate-studying instrument that was carried with the help of a helium balloon that lifted it into the atmosphere (HySICS Team/LASP)

Recent testing of a new climate-studying instrument that was carried with the help of a helium balloon that lifted it into the atmosphere (HySICS Team/LASP)

A Soyuz spacecraft carrying three new crewmembers for the International Space Station along with the Olympic Flame for the Sochi 2014 Winter Games blasts off from the Baikonur cosmodrome, in Kazakhstan on Thursday, Nov. 7, 2013. (AP/Dimitry Lovetsky)

A Soyuz spacecraft carrying three new crewmembers for the International Space Station along with the Olympic Flame for the Sochi 2014 Winter Games blasts off from the Baikonur cosmodrome, in Kazakhstan on Thursday, Nov. 7, 2013. (AP/Dimitry Lovetsky)

Sphyrna gilberti, a new species of scalloped hammerhead shark was recently found off the South Carolina coast. Researchers nicknamed it the Carolina Hammerhead. (University of South Carolina)

Sphyrna gilberti, a new species of scalloped hammerhead shark was recently found off the South Carolina coast. Researchers nicknamed it the Carolina Hammerhead. (University of South Carolina)

An X3.3 class solar flare taken by NASA's Solar Dynamics Observer at 5:12 p.m. EST Nov. 5, 2013. This composite image is made up of light blended from the 131 and 193 wavelengths. (NASA/SDO)

An X3.3 class solar flare taken by NASA’s Solar Dynamics Observer at 5:12 p.m. EST Nov. 5, 2013. This composite image is made up of light blended from the 131 and 193 wavelengths. (NASA/SDO)

Fossil Reveals New Species of Ancient Platypus

Posted November 5th, 2013 at 7:15 pm (UTC+0)
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Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus.  Fossil found in the World Heritage fossil deposits of Riversleigh, Australia. Unlike today's platypus this ancient species had teeth - see inset. (Peter Schouten)

Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus. Unlike today’s platypus, this ancient species had teeth (see inset). (Peter Schouten)

Australian scientists say they’ve found the fossil of a new species of  giant platypus that walked the Earth between 5 and 15 million years ago.

Up until now, the fossil record of the platypus indicated that only one species of the animal lived on Earth at any one time. The new study suggests this new extinct giant platypus species, called Obdurodon tharalkooschild, is a side-branch of the platypus family, rather than its direct ancestor.

The platypus is a mammal with a duck-like bill, thick fur that’s much like an otter’s, and a tail similar to a beaver’s. It has webbed feet and reproduces by laying eggs rather than giving birth like other mammals.

The animal was so odd that in 1798 when Captain John Hunter, then the governor of New South Wales, Australia, sent a pelt of a platypus along a sketch of the animal to scientists in Great Britain, the British researchers at first thought it was a joke or a hoax.

The Australian researchers were able to identify this new species of platypus from a single fossilized tooth found in the Riversleigh World Heritage Area of northwest Queensland, Australia.

Monotremes (platypuses and echidnas) are the last remnant of an ancient radiation of mammals unique to the southern continents,” said Rebecca Pian, lead author of the study. “A new platypus species, even one that is highly incomplete, is a very important aid in developing understanding about these fascinating mammals.”

The fossilized tooth’s size leads researchers to believe this ancient platypus was about a meter in length, two times the length of today’s platypus. Today, the male platypus grows to a length of about 50 cm while females grow to about 43 cm in length.

A modern day platypus swimming underwater at the Sydney Aquarium (wehunts via Flickr/Creative Commons)

A modern day platypus swimming underwater at the Sydney Aquarium (wehunts via Flickr/Creative Commons)

“Like other platypuses, it was probably a mostly aquatic mammal and would have lived in and around the freshwater pools in the forests that covered the Riversleigh area millions of years ago,” said Dr. Suzanne Hand of the University of New South Wales, a co-author of the study.

The ancient Obdurodon tharalkooschild was able to eat its prey with a set of well-developed teeth, unlike today’s platypus which has horny pads in its mouth instead.

The extinct platypus probably ate a varied menu that included not only crayfish and other freshwater crustaceans, but also small vertebrates such as lungfish, frogs, and small turtles.

The researchers named  the prehistoric animal Obdurodon, Greek for “lasting (obdurate) tooth,”  because its teeth are unlike today’s platypus species.  Tharalkooschild was given in honor of a story told by Indigenous Australians about the creation and origin of the platypus.

Dogs Communicate with Wag of a Tail

Posted November 1st, 2013 at 8:06 pm (UTC+0)
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A dog wagging its tail (Bill McChesney via Creative Commons @ Flickr)

(Bill McChesney via Creative Commons @ Flickr)

The direction in which a dog wags its tail can communicate its emotional state to other canines, according to a new study published in Current Biology.

The Italian research team behind the study says dogs recognize, and respond accordingly, whether other canines wag their tails to the right or to the left.

The reason dogs understand the right versus left tail wag, according to the researchers, is because they have asymmetrically organized brains, meaning that the left and right sides of our brains are each responsible for controlling different things, much like humans.

In an earlier study, the researchers found dogs tend to wag their tails to the right when they feel positive, such as when they see their owners. Dogs wag their tails to the left when they experience negative emotions, such as feelings that might be triggered by an unfriendly dog or some other kind of danger.

The researchers say that this left and right tail wagging behavior is because of what’s taking place in the canine’s brains. A wag to the right is brought on by activation on the left side of its brain, while activity in the right side of the brain produces a wag to the left.

While this right versus left wagging behavior means something to other dogs, the researchers say that they’re probably not purposely displaying this behavior to communicate with each other.  Instead they say it’s just an automatic response due to left side or right side brain activation. But the team also points out that this behavior could serve a very helpful purpose to people like dog owners and veterinarians as another way to better understand what’s going on with the animal.

Compilation of videos shown to test dogs – left, right, no tail wagging – (Current Biology, Siniscalchi et al.)

To make their findings the researchers showed their dog subjects videos of other dogs either wagging their tails to the left or right. When the test dogs saw a video of a dog wagging its tail to the left, their heart rates increased and they appeared a bit nervous. However, when the dogs saw another animal wagging its tail to the right, they remained calm.

“The direction of tail wagging does in fact matter, and it matters in a way that matches hemispheric activation,” said Giorgio Vallortigara of the Center for Mind/Brain Sciences of the University of Trento. “In other words, a dog looking to a dog wagging with a bias to the right side—and thus showing left-hemisphere activation as if it was experiencing some sort of positive/approach response—would also produce relaxed responses. In contrast, a dog looking to a dog wagging with a bias to the left—and thus showing right-hemisphere activation as if it was experiencing some sort of negative/withdrawal response—would also produce anxious and targeting responses as well as increased cardiac frequency. That is amazing, I think.”

US, India Prep for Unmanned Missions to Mars

Posted October 29th, 2013 at 5:36 pm (UTC+0)
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The planet Mars in late spring as imaged by the Hubble Space Telescope (NASA/JPL/California Institute of Technology)

The planet Mars in late spring as imaged by the Hubble Space Telescope (NASA)

Both the United States and India are gearing up for unmanned missions to Mars.

India will launch its first interplanetary spacecraft when the Indian Space Research Organization (ISRO) sends its Mars Orbiter Mission (MOM) to the Red Planet on Nov. 5. The spacecraft will be launched from the Satish Dhawan Space Centre located in Sriharikota, Andhra Pradesh, India.

According to ISRO, one of MOM’s main objectives is to allow the Indian space program to develop the technologies required to design, plan, manage and operate an interplanetary mission.

Once the MOM spacecraft arrives at Mars in September 2014, it will drop into orbit around the planet. Throughout its nearly year-long mission the MOM will explore the Martian surface and atmosphere.

India's Mars Orbiter Mission Spacecraft being integrated to the 4th stage of of its launch vehicle. (Indian Space Research Organization)

India’s Mars Orbiter Mission Spacecraft being integrated to the 4th stage of of its launch vehicle. (Indian Space Research Organization)

Meanwhile, NASA is making final preparations to launch a new unmanned mission to Mars that will allow scientists on Earth to examine the Red Planet’s atmosphere in greater detail.

Lift-off for the Mars Atmosphere and Volatile Evolution mission (MAVEN) is currently scheduled on Monday, Nov. 18 from Cape Canaveral Air Force Station in Florida.

In the course of its one-Earth-year primary mission, MAVEN will study the specific processes that led to Mars losing much of its atmosphere about 3.5 billion years ago.

Data sent back to Earth from MAVEN should help scientists gain a greater understanding of climate change on the Red Planet and learn more of the history of planetary habitability.

“The MAVEN mission is a significant step toward unraveling the planetary puzzle about Mars’ past and present environments,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington. “The knowledge we gain will build on past and current missions examining Mars and will help inform future missions to send humans to Mars.”

Artist's concept of the MAVEN spacecraft orbiting Mars. (NASA/Goddard Space Flight Center)

Artist’s concept of the MAVEN spacecraft orbiting Mars. (NASA)

Once it arrives at Mars, also in September 2014, and eases into its elliptical science orbit, the MAVEN will observe all of the Red Planet’s latitudes.  The spacecraft is expected to cruise around Mars at an altitude of between 158 and 6,115 km above its surface.

During its mission, MAVEN will also perform five of what NASA calls “deep dip maneuvers,” that will send the spacecraft down to an altitude of only 125 km above the surface of Mars, which scientists say is the lower boundary of the planet’s upper atmosphere.

ISRO said that NASA and its Jet Propulsion Laboratory will also provide communications and navigation support to the Indian MOM mission.

Gene Enhancers Give Human Face Its Final Look

Posted October 25th, 2013 at 8:19 pm (UTC+0)
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Every human face is as unique as a fingerprint (National Cancer Institute)

Each human face is as unique as a fingerprint. (National Cancer Institute)

When you look at yourself in the mirror, do you ever wonder why you look the way you do?  Do you also wonder what biological processes were at work when it came time to shape and sculpt your face, which is as individual and unique as a fingerprint?

The answer is in a little snippet of your DNA called a gene enhancer, according to scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab)

These little pieces of DNA help switch on, or boost the expression of specific genes that control the development of the face and head while in utero. What’s interesting about these little influential bits of DNA is that a gene enhancer doesn’t have to be found anywhere close to the genes it works on and, in some cases, doesn’t even have to be located on the same chromosome.

Of course, there are a number of hereditary factors, such as when a child resembles a parent, that help determine appearance. The researchers, who outlined their findings in the journal “Science,” said the gene enhancer fine-tunes the genetics to give your face its final unique look. Even with identical twins, there are subtle differences in appearance.

Identical twins Linda and Terry Jamison look similar but are not exactly the same in appearance.  Look for the differences. (Linda and Terry Jamison via Wikimedia Commons)

Identical twins Linda and Terry Jamison look similar but are not exactly the same in appearance.  (Linda and Terry Jamison via Wikimedia Commons)

“Our results suggest it is likely there are thousands of enhancers in the human genome that are somehow involved in craniofacial development,” said Axel Visel, a geneticist with Berkeley Lab’s Genomics Division, who led the research. “We don’t know yet what all of these enhancers do, but we do know that they are out there and they are important for craniofacial development.”

Scientists have previously been able to identify some of the genetic flaws that can cause birth defects, such as a cleft lip or palate, but haven’t been able to fully understand what genetic factors are responsible for normal, subtle differences in appearance.

In the past, Visel and his colleagues were able to map gene enhancers in the heart, brain and other vital organs. The researchers said their studies showed that gene enhancers can control their targets from across distances of hundreds of thousands of base pairs, which are each two chemical bases that scientists consider to be the fundamental components of the DNA double helix.

To find out if these gene enhancers have the same type of long-distance effect on the development of the head and face, the researchers studied transgenic mice or those that had been genetically modified.

They were able to identify more than 4,000 possible gene enhancer sequences they think play a role in fine-tuning the genes responsible for developing and defining the head and face.

Berkeley Lab researchers identified distant-acting transcriptional enhancers in the developing craniofacial structure.  Changes in appearance made by removing one of these enhancers shown in red. (Berkeley Labs)

Berkeley Lab researchers identified distant-acting transcriptional enhancers in the developing craniofacial structure. The changes in appearance made by removing one of these enhancers are shown in red. (Berkeley Labs)

A later analysis of their data showed that removing a few of these individual craniofacial enhancers can cause changes to the shape of the head and/or face.

“Our results also offer an opportunity for human geneticists to look for mutations specifically in enhancers that may play a role in birth defects, which in turn may help to develop better diagnostic and therapeutic approaches,” said Visel.

While the researchers continue their own research, they are also working with geneticists to carry out specialized searches to look for mutations within the enhancer sequences of humans with craniofacial birth defects.

Study Suggests a Significant Change to Human History

Posted October 18th, 2013 at 6:40 pm (UTC+0)
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This is "Skull 5" that was found at the Dmanisi, Georgia dig site. (Georgian National Museum)

This is “Skull 5″ that was found at the Dmanisi, Georgia dig site. (Georgian National Museum)

An international team of scientists claim that their recent research could rewrite the history of human evolution.

The researchers suggest that instead of our early human ancestors belonging to different evolutionary species such as Homo habilis, Homo rudolfensis or Homo erectus, they are all actually of the same species, but just happen to look a bit different from each another.

Writing in the journal Science, the scientists from Georgia, Switzerland, Israel and the U.S. came to their conclusions after studying a 1.8-million-year-old skull from the early Pleistocene epoch that was unearthed in Dmanisi, Georgia.

According to the researchers, the skull they studied, called Skull 5, is not like other fossils of the Homo genus.  Skull 5, they said, reveals a combination of a braincase that’s about 546 cubic centimeters along with a long face and large teeth.

Despite having limb proportions and the body size of a modern human, the researchers said that the small braincase of Skull 5 indicates that this early human ancestor had a small brain.

The skull was found with the remains of four other human ancestors along with other material that included an assortment of animal fossils and some stone tools.

Dmanisi, Georgia excavation site circa 2007 (Georgian National Museum)

Dmanisi, Georgia excavation site circa 2007 (Georgian National Museum)

The researchers said this was a unique find since all of the unearthed material could be associated with the same time period and location.

In examining and analyzing “Skull 5”, the researchers said that they found that the differences between the various fossils were no more noticeable than those between five modern humans or five chimpanzees.

“Had the braincase and the face of Skull 5 been found as separate fossils at different sites in Africa, they might have been attributed to different species,” said Christoph Zollikofer from the Anthropological Institute and Museum in Zurich, Switzerland and a co-author of the report. “That’s because Skull 5 unites some key features, like the tiny braincase and large face, which had not been observed together in an early Homo fossil until now.”

Researchers previously have typically considered variations among Homo fossils as an indication that they were of different species.

But those involved with this recent study say that their findings suggest that fossils of various early members of the human family, all originating in Africa, are part of one evolving lineage, probably what is known as Homo erectus. Previous research indicates that this now extinct hominid lived as recently as 143,000 to about 1.8 million years ago.

Study suggests that other human ancestor species may actually belong to the species Homo erectus seen here in this reconstruction. (Westfälisches Landesmuseum via Wikimedia Commons)

Study suggests that other human ancestor species may actually belong to the species Homo erectus seen here in this reconstruction. (Westfälisches Landesmuseum via Wikimedia Commons)

“[The Dmanisi finds] look quite different from one another, so it’s tempting to publish them as different species,” explained Zollikofer. “Yet we know that these individuals came from the same location and the same geological time, so they could, in principle, represent a single population of a single species.”

Checking the African fossil record, the researchers said that they also noticed a similar pattern and range of variation in the African fossil record so they figured that it was safe to assume that there was a single Homo species at that time in Africa too.

Furthermore, the researchers also found that since the hominid fossils recovered from the Dmanisi site are so similar to those found in Africa, they theorize that they are also both of the same species.

While the Georgian dig site is already providing opportunities for researchers to “compare and contrast” the physical characteristics of a number of human ancestors that happened to be in the same place and time, scientists expect even more evidence to be uncovered, since the site has only been partially excavated.

Scientists Make Progress on Artificial Limbs That Can Feel

Posted October 15th, 2013 at 6:13 pm (UTC+0)
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(PNAS, 2013)

(PNAS, 2013)

Chicago researchers have made significant progress developing prosthetic limbs that can feel and touch.

Writing in the Proceedings of the National Academy of Sciences, the researchers say they’ve established a foundation to develop touch-sensitive prosthetic limbs.

This research could lead to a direct interface with the brain that could someday allow those who have lost limbs to, not only manipulate objects, but also to be able to touch and feel again.

“To restore sensory motor function of an arm, you not only have to replace the motor signals that the brain sends to the arm to move it around, but you also have to replace the sensory signals that the arm sends back to the brain,” said  Sliman Bensmaia of the University of Chicago. “We think the key is to invoke what we know about how the brain of the intact organism processes sensory information, and then try to reproduce these patterns of neural activity through stimulation of the brain.”

The research by the Chicago team is part of a project, under way since 2006, called Revolutionizing Prosthetics at the Defense Advanced Research Projects Agency (DARPA).  Researchers hope to create a modular artificial upper limb that will restore an amputee’s natural motor control and sensation.

The work being done by the Chicago research team focuses on developing the sensory aspects of the prosthetic limbs. Their experiments have been conducted with monkeys since the animals’ sensory systems are similar to humans.

The researchers said  they’ve been able to identify patterns of neural activity which occur when an object is being manipulated and then artificially replicate those patterns.

In their first experiment, the researchers wanted to learn more about sensing where the skin was touched. They trained the test monkeys to recognize several types of physical contact with their fingers and then connected electrodes to parts of the monkey’s brains related to each of their fingers. Instead of using actual physical touches, they substituted them with electrical stimulation directed to those specific areas of their brains. As a result, the researchers found that the monkeys reacted to the electrical stimulation the same way they did with actual physical contact.

Experiments were conducted on rhesus macaque monkeys, such as the one in this picture taken at Kinnerasani Wildlife Sanctuary, Andhra Pradesh, India. (J.M. Garg/Wikimedia Commons)

Experiments were conducted on rhesus macaque monkeys, such as the one in this picture taken at Kinnerasani Wildlife Sanctuary, Andhra Pradesh, India. (J.M. Garg/Wikimedia Commons)

The next area the researchers wanted to concentrate on was sense of pressure on the skin. They came up with an algorithm that would produce the proper amount of electrical current to artificially produce the sensation of pressure. As in their first experiment, the researchers found  their test animals responded the same way whether the sensation was actually felt through their fingers or reproduced artificially.

Finally, the researchers looked into the natural sensations that are felt when a hand first touches or releases an object. Since this series of events also produces bursts of activity in the brain, the research team was able to provide direct stimulation to the brain that also duplicated those sensations.

The experiments helped the scientists develop computer instructions to be incorporated into a robotic prosthetic arm.  They said that these instructions, working with the robotic appendage and through a neural interface, will be able to deliver sensory responses that mimic natural sensations of touch directly to the brain.

With the progress that the researchers have made with their animal experimentation, they hope to soon be able to test their devices during clinical trials with humans.

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