New procedure repairs severed nerves in minutes, restoring limb use in days or weeks
February 4, 2012
American scientists believe a new procedure to repair severed nerves could result in patients recovering in days or weeks, rather than months or years. The team used a cellular mechanism similar to that used by many invertebrates to repair damage to nerve axons. Their results are published today in the Journal of Neuroscience Research.
“We have developed a procedure which can repair severed nerves within minutes so that the behavior they control can be partially restored within days and often largely restored within two to four weeks,” said Professor George Bittner from the University of Texas. “If further developed in clinical trials this approach would be a great advance on current procedures that usually imperfectly restore lost function within months at best.”
The team studied the mechanisms all animal cells use to repair damage to their membranes and focused on invertebrates, which have a superior ability to regenerate nerve axons compared to mammals. An axon is a long extension arising from a nerve cell body that communicates with other nerve cells or with muscles.
This research success arises from Bittner’s discovery that nerve axons of invertebrates which have been severed from their cell body do not degenerate within days, as happens with mammals, but can survive for months, or even years.
The severed proximal nerve axon in invertebrates can also reconnect with its surviving distal nerve axon to produce much quicker and much better restoration of behaviour than occurs in mammals.
“Severed invertebrate nerve axons can reconnect proximal and distal ends of severed nerve axons within seven days, allowing a rate of behavioural recovery that is far superior to mammals,” said Bittner. “In mammals the severed distal axonal stump degenerates within three days and it can take nerve growths from proximal axonal stumps months or years to regenerate and restore use of muscles or sensory areas, often with less accuracy and with much less function being restored.”
The team described their success in applying this process to rats in two research papers published today. The team were able to repair severed sciatic nerves in the upper thigh, with results showing the rats were able to use their limb within a week and had much function restored within 2 to 4 weeks, in some cases to almost full function.
“We used rats as an experimental model to demonstrate how severed nerve axons can be repaired. Without our procedure, the return of nearly full function rarely comes close to happening,” said Bittner. “The sciatic nerve controls all muscle movement of the leg of all mammals and this new approach to repairing nerve axons could almost-certainly be just as successful in humans.”
To explore the long term implications and medical uses of this procedure, MD’s and other scientist- collaborators at Harvard Medical School and Vanderbilt Medical School and Hospitals are conducting studies to obtain approval to begin clinical trials.
“We believe this procedure could produce a transformational change in the way nerve injuries are repaired,” concluded Bittner.
Contact: Ben Norman
Lifesciencenews@wiley.com
44-012-437-70375
Wiley-Blackwell
Does antimatter weigh more, less or the same as matter?
January 26, 2012
Does antimatter behave differently in gravity than matter? Physicists at the University of California, Riverside have set out to determine the answer. Should they find it, it could explain why the universe seems to have no antimatter and why it is expanding at an ever increasing rate.
In the lab, the researchers took the first step towards measuring the free fall of “positronium” – a bound state between a positron and an electron. The positron is the antimatter version of the electron. It has identical mass to the electron, but a positive charge. If a positron and electron encounter each other, they annihilate to produce two gamma rays.
Physicists David Cassidy and Allen Mills first separated the positron from the electron in positronium so that this unstable system would resist annihilation long enough for the physicists to measure the effect of gravity on it.
“Using lasers we excited positronium to what is called a Rydberg state, which renders the atom very weakly bound, with the electron and positron being far away from each other,” said Cassidy, an assistant project scientist in the Department of Physics and Astronomy, who works in Mills’s lab. “This stops them from destroying each other for a while, which means you can do experiments with them.”
Rydberg atoms are highly excited atoms. They are interesting to physicists because many of the atoms’ properties become exaggerated.
In the case of positronium, Cassidy and Mills, a professor of physics and astronomy, were interested in achieving a long lifetime for the atom in their experiment. At the Rydberg level, positronium’s lifetime increases by a factor of 10 to 100.
“But that’s not enough for what we’re trying to do,” Cassidy said. “In the near future we will use a technique that imparts a high angular momentum to Rydberg atoms,” Cassidy said. “This makes it more difficult for the atoms to decay, and they might live for up to 10 milliseconds – an increase by a factor of 10,000 – and offer themselves up for closer study.”
Cassidy and Mills already have made Rydberg positronium in large numbers in the lab. Next, they will excite them further to achieve lifetimes of a few milliseconds. They will then make a beam of these super-excited atoms to study its deflection due to gravity.
“We will look at the deflection of the beam as a function of flight time to see if gravity is bending it,” Cassidy explained. “If we find that antimatter and matter don’t behave in the same way, it would be very shocking to the physics world. Currently there is an assumption that matter and antimatter are exactly the same – other than a few properties like charge. This assumption leads to the expectation that they should both have been created in equal amounts in the Big Bang. But we do not see much antimatter in the universe, so physicists are searching for differences between matter and antimatter to explain this.”
Study results appear in the Jan. 27 issue of Physical Review Letters.
Cassidy and Mills expect to attempt the next step in their gravity experiments this summer.
They were joined in the research by Harry Tom, a professor of physics and astronomy, and Tomu H. Hisakado, a graduate student in Mills’s lab.
The research is being supported by grants from the National Science Foundation and the U.S. Air Force Research Office.
The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California’s diverse culture, UCR’s enrollment has exceeded 20,500 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.
Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California – Riverside
Mysterious monkey re-discovered in Borneo
January 22, 2012
Simon Fraser University PhD student Brent Loken was hoping to capture images of the elusive Bornean clouded leopard when he set up a camera trap in the rainforest. Instead, he made the re-discovery of a lifetime.
Reviewing time-lapse photos taken at a mineral lick in the Wehea Forest of East Kalimantan last June, he and his fellow researchers were stunned to see an animal they didn’t recognize. The pictures showed Miller’s grizzled langur, one of the rarest and least-known primates on the island of Borneo, and also a species many suggested was extinct or on the verge of extinction.
“It was a challenge to confirm our finding as there are so few pictures of this monkey available for study,” says Loken, who is in SFU’s resource and environmental management program. “The only description of Miller’s grizzled langur came from museum specimens. Our photographs from Wehea are some of the only pictures that we have of this monkey.”
Loken’s work is featured in a paper being published online this week in the American Journal of Primatology (print version, March 2012).
A former secondary-school principal and science teacher, Loken holds both Trudeau and Vanier scholarships. He spends up to six months each year in Borneo where he runs Ethical Expeditions, a non-profit organization he co-founded to help the indigenous Wehea Dayak people fight back against deforestation. The island has lost 65 per cent of its rainforest, largely due to palm oil plantations and coal mines.
“Finding Miller’s grizzled langur in a forest outside of its known geographic range highlights how much we don’t know about even the basic ecology of this monkey,” says Loken. “We need more scientists doing research in Borneo to help us learn about understudied species such as Miller’s grizzled langur and clouded leopards. The rapid degradation of Borneo’s forests makes it difficult to learn about and adopt conservation strategies in time to protect species.”
Loken’s camera traps were part of a larger biodiversity study he organized in collaboration with the local Wehea Dayak community to investigate the diversity and abundance of animals that were living in this remote forest.
Balancing scientific freedom and national security
January 19, 2012
The U.S. government’s request that the journals Science and Nature withhold scientific information related to the genetically modified H5N1 virus because of biosecurity concerns does not violate the First Amendment, say two Georgetown University professors. They caution, however, that a fair, transparent process undertaken by research organizations is preferable to governmental constraints on disseminating scientific information.
Writing in Science, John D. Kraemer, JD, MPH, assistant professor of health systems administration at Georgetown University School of Nursing & Health Studies, and Lawrence O. Gostin, the Linda D. and Timothy J. O’Neill Professor of Global Health Law and faculty director of the O’Neill Institute for National and Global Health Law at Georgetown University Law Center, explore the balance of scientific freedom and national security in their opinion piece published online today entitled, “The Limits of Government Regulation of Science.”
In 2011, two research teams genetically modified the H5N1 avian influenza virus. Their work, funded by the National Institutes of Health (NIH), demonstrates the ability to alter a virus in such a way that it could possibly spread rapidly among humans – killing more than half who contract it (the research was conducted in an animal model believed to represent human behavior of the virus). The research prompted the National Science Advisory Board for Biosecurity (NSABB), which advises the Department of Health and Human Services (HHS), to recommend that Science and Nature redact key information prior to publication. Both NSABB and HHS expressed concerns that published details about the papers’ methodology and results could become a blueprint for bioterrorism.
“The NSABB process seems to have worked well in this instance,” says Kraemer. “It raised legitimate security concerns while avoiding censorship of the scientific press. But there remains a need to strengthen precautions around this type of research before it occurs.”
To date, Science and Nature have not yet announced their intentions regarding the government’s request.
In their commentary, Kraemer and Gostin write “HHS’ request reveals a troubled relationship between security and science.” However, the authors point out, “Given the absence of legal force or undue inducements or penalties, the government’s request to withhold information does not violate the First Amendment.”
Kraemer and Gostin say the First Amendment, “affords considerable protection to political artistic and scientific expression, triggering ‘strict scrutiny’ by the Supreme Court.” They point out that had the government compelled either the researchers or the journals to withhold publication, that act would have violated the First Amendment.
In their opinion piece, the authors explore various court cases that challenge and support the government’s rights to go further with such an issue. They say the federal government has the power to prevent dissemination of sensitive life science research, but warn, “ there are good reasons to exercise that power sparingly.”
Looking beyond the current dilemma, Kraemer and Gostin ask: “Can the review process for high-risk biologic research be improved further?”
The origins of the National Science Advisory Board for Biosecurity can be traced to the National Research Council’s Fink Report issued in 2004. The Fink Report endorsed, among other things, expanded self-governance by researchers toward issues of biosecurity, as well as the formation of a national advisory board to help guide both the government and research community in addressing issues involving dual-use research.
However, Kraemer and Gostin point out that vital recommendations in the Fink Report have not yet been implemented, including the need to employ an institutional review process for biological “experiments of concern” patterned on the Institutional Biosafety Committees (IBC) required for recombinant DNA research.
Kraemer and Gostin make the following recommendations to improve the review process:
HHS, in partnership with institutions, will have to ensure that the IBC model works effectively: (1) institutions must develop the requisite expertise to review dual use research; (2) HHS must specify the categories of research requiring institutional review – minimally including the 7 types of high-risk experiments; and (3) HHS must set clear and consistent standards for institutional review. If IBCs are formally designated to conduct the institutional review function, HHS will have to clarify whether NSABB will guide and oversee the process.
Kraemer and Gostin suggest that such a process can ensure a, “sound balance between scientific freedom and national security. A fair, transparent process undertaken by research institutions, with a balanced approach to scientific benefits and public safety, together with HHS guidance and oversight of high-risk research, is preferable to government constraints on scientific information by force of law.”
About Georgetown University Law Center
Georgetown University Law Center is one of the world’s premier law schools. It is pre-eminent in several areas, including constitutional, international, tax and clinical law, and the faculty is among the largest in the nation. Drawing on its Jesuit heritage, it has a strong tradition of public service and is dedicated to the principle that law is but a means, justice is the end. With this principle in mind, Georgetown Law has built an environment that cultivates an exchange of ideas and the pursuit of academic excellence. It brings together an extraordinarily varied group of teachers, scholars and practitioners, as well as an outstanding student body representing more than 60 countries.
About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through MedStar Health). GUMC’s mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis — or “care of the whole person.” The Medical Center includes the School of Medicine and the School of Nursing & Health Studies, both nationally ranked; Georgetown Lombardi Comprehensive Cancer Center, designated as a comprehensive cancer center by the National Cancer Institute; and the Biomedical Graduate Research Organization (BGRO), which accounts for the majority of externally funded research at GUMC including a Clinical Translation and Science Award from the National Institutes of Health. In fiscal year 2010-11, GUMC accounted for 85 percent of the university’s sponsored research funding.
Contact: Karen Mallet
km463@georgetown.edu
Georgetown University Medical Center
Research reveals power of the subconscious in human fear
January 18, 2012
The human subconscious has a bigger impact than previously thought on how we respond to danger, according to research led by the University of Exeter. Published today (I8 January), the study shows that our primitive response to fear can contradict our conscious assessment of danger.
The findings have implications for how anxiety disorders, such as phobias, are treated. The research also suggests we share a primitive response to fear with other animals, despite being able to consciously anticipate and assess danger.
Participants recruited to the study sat in front of a screen, on which a coloured shape sometimes appeared. Half the time, the image was accompanied by a mild electric shock. For the rest of the time, the image appeared but no shock was given.
During the trial they were asked to rate whether or not they expected a shock to be given and their ‘skin conductance’ was monitored. This technique measures the variation in the electrical activity of the sweat glands in the skin, which is an indication of the state of arousal of the sympathetic nervous system. In other words, it gives us a reading of a person’s emotional state.
Following a series of trials involving shocks, participants were more likely to predict they would not receive a shock when the image was next shown. The complementary result was that they generally anticipated receiving a shock if they had not had one for the last few images. This phenomenon of expecting good luck after a run of bad luck and vice versa, is known as the ‘gambler’s fallacy’.
The skin conductance responses revealed the opposite pattern. Following a series of shocks accompanying the image, their physical responses to the next image shown suggested participants were more likely to expect another shock, but that they were less likely to expect a shock after a run of no-shock trials. This pattern of responding is consistent with ‘associative learning’: associating a visual cue with a significant event, a phenomenon that is well known in animals.
Previously it has been thought that, when using this type of procedure, humans respond differently from animals because we rely on conscious reasoning, rather than associative learning to generate our expectations. This study suggests that, despite our sophisticated mental capabilities, our responses are in fact driven by these more primitive processes when in danger.
Lead author, Professor Ian McLaren of the University of Exeter said: “This research clearly shows that, in these circumstances, our reaction to a fear-provoking stimulus depends on a primitive response caused by associative learning. This is something we share with other animals.
“This could have important practical implications. Now that we know that associative processes are implicated in our response to fear-inducing stimuli, we need to consider the implications for the ways in which we treat anxiety and phobias.”
Contact: Sarah Hoyle
s.hoyle@exeter.ac.uk
44-013-927-22062
University of Exeter
Potential new therapy approach for hepatitis C identified
January 16, 2012
Researchers at the University of British Columbia have found a new way to block infection from the hepatitis C virus (HCV) in the liver that could lead to new therapies for those affected by this and other infectious diseases.
More than 170 million people worldwide suffer from hepatitis C, the disease caused by chronic HCV infection. The disease affects the liver and is one of the leading causes of liver cancer and liver transplant around the world. HCV is spread by blood-to-blood contact and there is no vaccine to prevent it. Current treatments for the disease are only moderately effective and can cause serious side effects.
“As HCV infects a person, it needs fat droplets in the liver to form new virus particles,” says François Jean, Associate Professor in the Department of Microbiology and Immunology and Scientific Director of the Facility for Infectious Disease and Epidemic Research (FINDER) at UBC. “In the process, it causes fat to accumulate in the liver and ultimately leads to chronic dysfunction of the organ.”
“HCV is constantly mutating, which makes it difficult to develop antiviral therapies that target the virus itself,” says Jean. “So we decided to take a new approach.”
Jean and his team developed an inhibitor that decreases the size of host fat droplets in liver cells and stops HCV from “taking residence,” multiplying and infecting other cells.
“Our approach would essentially block the lifecycle of the virus so that it cannot spread and cause further damage to the liver,” says Jean. The team’s method is detailed in the journal PLoS Pathogens.
According to Jean, HCV is one of a number of viruses that require fat to replicate in the human body. This new approach to curbing the replication of HCV could translate into similar therapies for other related re-emerging viruses that can cause serious and life threatening infections in humans, such as dengue virus. Dengue is endemic in more than 100 countries, with approximately 2.5 billion people at risk of infection globally. In some countries, Dengue has become the leading cause of child mortality.
The research was supported by the Canadian Institutes of Health Research (CIHR) through grants and scholarships and by the Michael Smith Foundation for Health Research (MSFHR) through its Junior Trainee Award. The study is available at http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002468
Contact: Brian Lin
brian.lin@ubc.ca
604-822-2234
University of British Columbia
I recognize you! But how did I do it?
January 14, 2012
Are you someone who easily recognises everyone you’ve ever met? Or maybe you struggle, even with familiar faces? It is already known that we are better at recognising faces from our own race but researchers have only recently questioned how we assimilate the information we use to recognise people.
New research by the University of Nottingham Malaysia Campus has shown that when it comes to recognising people the Malaysian Chinese have adapted their facial recognition techniques to cope with living in a multicultural environment.
The study ‘You Look Familiar: How Malaysian Chinese Recognise Faces’ was led by Chrystalle B.Y. Tan, a PhD student at the University of Nottingham Malaysia Campus. The results have been published online in the prestigious scientific journal PloS One, This research is the first PhD student publication for Nottingham’s School of Psychology in Malaysia.
Chrystalle Tan said: “Our research has shown that Malaysian Chinese adopt a unique looking pattern which differed from both Westerners and Mainland Chinese, possibly due to the multicultural nature of the country.”
The ability to recognise different faces may have social and evolutionary advantages. Human faces provide vital information about a person’s identity and characteristics such as gender, age, health and attractiveness. Although we all have the same basic features we have our own distinguishing features and there is evidence that the brain has a specialised mental module dedicated to face processing.
Recognition techniques
Previous research by a group at Glasgow University in Scotland showed that Asians from mainland China use more holistic recognition techniques to recognise faces than Westerners.
- Chinese focus on the centre of the face in the nose area
- Westerners focus on a triangular area between the eyes and mouth
- British born Chinese use both techniques fixating predominantly around either the eyes and mouth, or the nose
Chrystalle said: “The traditional view is that people recognise faces by looking in turn at each eye and then the mouth. This previous research showed us that some Asian groups actually focus on the centre of the face, in the nose area. While Westerners are learning what each separate part of the face looks like – a strategy that could be useful in populations where hair and eye colour vary dramatically, mainland Chinese use a more global strategy, using information about how the features are arranged. Meanwhile British born Chinese use a mixture of both techniques suggesting an increased familiarity with other-race faces which enhances their recognition abilities.”
Eye tracking technology
The study by the School of Psychology at the University of Nottingham Malaysia Campus set out to investigate whether exposure and familiarity with other cultures affects our recognition accuracy and eye movement strategies.
The team used specialised eye tracking technology to investigate the visual strategies used to recognise photographs of faces. They recruited 22 Malaysian Chinese student volunteers from across Nottingham’s Malaysia campus. The results showed that Malaysian Chinese used a unique mixed strategy by focusing on the eyes and nose more than the mouth.
Chrystalle said: “We have shown that Malaysian Chinese adopt a unique looking pattern which differed from both Westerners and mainland Chinese. This combination of Eastern and Western looking patterns proved advantageous for Malaysian Chinese to accurately recognise Chinese and Caucasian faces.”
The study was supervised by Dr Ian Stephen, an expert on face processing and Dr Elizabeth Sheppard, an expert in eye tracking. Dr Stephen said: “We think that people learn how to recognise faces from the faces that they encounter. Although Malaysia is an East Asian country its ethnic composition is highly diverse. The intermediate looking strategy that Malaysian Chinese use allows them to recognise Western faces just as well as Asians.”
Contact: Lindsay Brooke
lindsay.brooke@nottingham.ac.uk
44-115-951-5751
University of Nottingham
Planets around stars are the rule rather than the exception
January 12, 2012
There are more exoplanets further away from their parent stars than originally thought, according to new astrophysics research.
In a new paper appearing in the Jan. 12 edition of the journal, Nature, astrophysicist Kem Cook as part of an international collaboration, analyzed microlensing data that bridges the gap between a recent finding of planets further away from their parent stars and observations of planets extremely close to their parent star. The results point to more planetary systems resembling our solar system rather than being significantly different.
Gravitational microlensing occurs when light from a source star is bent and focused by gravity as a second object (the lens star), which passes between the source star and an observer on Earth. A planet rotating around the lens star will produce an additional deviation in the microlensing. The first gravitational microlensing observations were made by the Massive Astrophysical Compact Halo Object (MACHO) collaboration, led by Livermore scientists.
The new research also determines that a large fraction of planets have orbital distances from 0.5 to 10 sun-Earth distances. In the past, using the Doppler shift technique, most extrasolar planets found were gas giants like Jupiter and Saturn that orbited stars that were much closer to them than the sun is to Earth.
An exoplanet is a planet outside our solar system. Over the past 16 years, astronomers have detected more than 700 confirmed exoplanets and have started to probe the spectra and atmospheres of these worlds. While studying the properties of individual exoplanets is undeniably valuable, a much more basic question remains: how commonplace are planets in the Milky Way?
The team found that approximately 17 percent of stars host Jupiter-mass planets. However, cool-Neptunes and super-Earths are more common, occurring 52 percent and 62 percent, respectively, of the time.
Gravitationally microlensing is very rare. In fact, fewer stars than one per million undergo micolensing at any time.
The team’s result is consistent with every star of the Milky Way, hosting, on average, one planet or more in an orbital distance range of 0.5 to 10 sun-Earth distances.
“Our measurements confirm that low-mass planets are very common and the number of planets increases with decreasing planet mass, in an agreement with the predictions of the core accretion scenario of planet formation,” Cook said. “Planets around stars in our galaxy appear to be the rule rather than the exception.”
“We used to think that the Earth might be unique in our galaxy. But now it seems that there are literally billions of planets with masses similar to Earth orbiting stars in the Milky Way,” concludes Daniel Kuba, of the European Southern Observatory and co-lead author of the paper .
Founded in 1952, Lawrence Livermore National Laboratory (www.llnl.gov) provides solutions to our nation’s most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy’s National Nuclear Security Administration.
Contact: Anne Stark
stark8@llnl.gov
925-422-9799
DOE/Lawrence Livermore National Laboratory
Astronomers reach new frontiers of dark matter
January 9, 2012
For the first time, astronomers have mapped dark matter on the largest scale ever observed. The results, presented by Dr Catherine Heymans of the University of Edinburgh, Scotland, and Associate Professor Ludovic Van Waerbeke of the University of British Columbia, Vancouver, Canada, are being presented today to the American Astronomical Society meeting in Austin, Texas. Their findings reveal a Universe comprised of an intricate cosmic web of dark matter and galaxies spanning more than one billion light years.
An international team of researchers lead by Van Waerbeke and Heymans achieved their results by analysing images of about 10 million galaxies in four different regions of the sky. They studied the distortion of the light emitted from these galaxies, which is bent as it passes massive clumps of dark matter during its journey to Earth.
Their project, known as the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS), uses data from the Canada-France-Hawaii Telescope Legacy Survey. This accumulated images over five years using the wide field imaging camera MegaCam, a 1 degree by 1 degree field-of-view, 340 Megapixel camera on the CFHT in Hawaii.
Galaxies included in the survey are typically six billion light years away. The light captured by the images used in the study was emitted when the Universe was six billion years old – roughly half the age it is today.
The team’s result has been suspected for a long time from studies based on computer simulations, but was difficult to verify owing to the invisible nature of dark matter. This is the first direct glimpse at dark matter on large scales showing the cosmic web in all directions.
Professor Ludovic Van Waerbeke, from the University of British Columbia, said: “It is fascinating to be able to ‘see’ the dark matter using space-time distortion. It gives us privileged access to this mysterious mass in the Universe which cannot be observed otherwise. Knowing how dark matter is distributed is the very first step towards understanding its nature and how it fits within our current knowledge of physics.”
Dr Catherine Heymans, a Lecturer in the University of Edinburgh’s School of Physics and Astronomy, said: “By analysing light from the distant Universe, we can learn about what it has travelled through on its journey to reach us. We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our Universe.”
Dr Christian Veillet, CFHT Executive Director, said “This dark matter study illustrates the strong legacy value of the CFHT Legacy Survey which is now enabling exciting results obtained by teams from many nations which use the images retrieved from the Canadian Astronomy Data Centre where they are archived and publicly available”.
Professor Lance Miller, from Oxford University said: “This result has been achieved through advances in our analysis techniques which we are now applying to data from the Very Large Telescope’s (VLT) Survey Telescope in Chile.”
Professor Koen Kuijken, from Leiden University, said: “Over the next three years we will image more than 10 times the area mapped by CFHTLenS, bringing us ever closer to our goal of understanding the mysterious dark side of the Universe.”
Image Caption: The observations show that dark matter in the Universe is distributed as a network of gigantic dense (white) and empty (dark) regions, where the largest white regions are about the size of an Earth moon on the sky. Credit: Van Waerbeke, Heymans and the CFHTLenS Collaboration
More images are available at:
www.cfhtlens.org
www.cfht.hawaii.edu/en/news/CFHTLens
This research was supported by the European Research Council, Natural Sciences and Engineering Research Council of Canada, the Canadian Institute for Advanced Research and the Canadian Astronomy Data Centre.
Contact: Catriona Kelly
catriona.kelly@ed.ac.uk
44-131-651-4401
University of Edinburgh
Earth’s massive extinction: The story gets worse
January 6, 2012
Scientists have uncovered a lot about the Earth’s greatest extinction event that took place 250 million years ago when rapid climate change wiped out nearly all marine species and a majority of those on land. Now, they have discovered a new culprit likely involved in the annihilation: an influx of mercury into the eco-system.
“No one had ever looked to see if mercury was a potential culprit. This was a time of the greatest volcanic activity in Earth’s history and we know today that the largest source of mercury comes from volcanic eruptions,” says Dr. Steve Grasby, co-author of a paper published this month in the journal Geology. “We estimate that the mercury released then could have been up to 30 times greater than today’s volcanic activity, making the event truly catastrophic.” Grasby is a research scientist at Natural Resources Canada and an adjunct professor at the University of Calgary.
Dr. Benoit Beauchamp, professor of geology at the University of Calgary, says this study is significant because it’s the first time mercury has been linked to the cause of the massive extinction that took place during the end of the Permian.
“Geologists, including myself should be taking notes and taking another look at the other five big extinction events,” says Beauchamp, also a co-author.
During the late Permian, the natural buffering system in the ocean became overloaded with mercury contributing to the loss of 95 per cent of life in the sea.
“Typically, algae acts like a scavenger and buries the mercury in the sediment, mitigating the effect in the oceans,” says lead-author Dr. Hamed Sanei, research scientist at Natural Resources Canada and adjunct professor at the University of Calgary. “But in this case, the load was just so huge that it could not stop the damage.”
About 250 million years ago, a time long before dinosaurs ruled and when all land formed one big continent, the majority of life in the ocean and on land was wiped out. The generally accepted idea is that volcanic eruptions burned though coal beds, releasing CO2 and other deadly toxins. Direct proof of this theory was outlined in a paper that was published by these same authors last January in Nature Geoscience.
The mercury deposition rates could have been significantly higher in the late Permian when compared with today’s human-caused emissions. In some cases, levels of mercury in the late Permian ocean was similar to what is found near highly contaminated ponds near smelters, where the aquatic system is severely damaged, say researchers.
“We are adding to the levels through industrial emissions. This is a warning for us here on Earth today,” adds Beauchamp. Canada has taken a lead role in reducing emissions internationally. In North America, at least, there has been a steady decline through regulations controlling mercury.
No matter what happens, this study shows life’s tenacity. “The story is one of recovery as well. After the system was overloaded and most of life was destroyed, the oceans were still able to self clean and we were able to move on to the next phase of life,” says Sanei.
Contact: Leanne Yohemas
lmyohema@ucalgary.ca
403-540-6552
University of Calgary