Utrecht, Canada
Utrecht, Canada

Time filter

Source Type

Hunting is a major threat to wildlife particularly in tropical regions, but a systematic large-scale estimate of hunting-induced declines of animal numbers was lacking so far. A study published in Science on April 14 fills this gap. An international team of ecologists and environmental scientists found that bird and mammal populations were reduced within 7 and 40 km of hunters' access points, such as roads and settlements. Within these impact zones, mammal populations declined on average by 83% and bird populations by 58%. Additionally, the team found that commercial hunting had a higher impact than hunting for family food, and that hunting pressure was higher in areas with better accessibility to major towns where wild meat could be traded. The impact of hunting was found to be larger than the team expected. 'Thanks to this study, we estimate that only 17 percent of the original mammal abundance and 42 percent of the birds remain in hunted areas.' The researchers synthesised 176 studies to quantify hunting-induced declines of mammal and bird populations across the tropics of Central and South America, Africa and Asia. The study was led by Ana Benítez-López, who works at the department of Environmental Science at Radboud University in Nijmegen, the Netherlands. She cooperated with researchers from the Netherlands Environmental Assessment Agency (PBL), the universities of Wageningen and Utrecht in the Netherlands and a colleague from the School of Life Sciences, University of Sussex. 'There are several drivers of animal decline in tropical landscapes: habitat destruction, overhunting, fragmentation etcetera. While deforestation and habitat loss can be monitored using remote sensing, hunting can only be tracked on the ground. We wanted to find a systematic and consistent way to estimate the impact of hunting across the tropics. As a starting point, we used the hypothesis that humans gather resources in a circle around their village and in the proximity of roads. As such, hunting pressure is higher in the proximity of villages and other access points. From there the densities of species increase up to a distance where no effect of hunting is observed. We called this species depletion distances which we quantified in our analysis. This allowed us to map hunting-induced declines across the tropics for the first time,' Benítez-López explains. Not only the big cuddly species The main novelty of the current study is that it combined the evidence across many local studies, thus for the first time providing an overarching picture of the magnitude of the impact across a large number of species. The study takes all animals into account - not only the big cuddly species, but birds and rodents as well. Benítez-López explains the difference in impact between birds and mammals: 'Mammals are more sought after because they're bigger and provide more food. They are worth a longer trip. The bigger the mammal, the further a hunter would walk to catch it.' With increasing wild meat demand for rural and urban supply, hunters have harvested the larger species almost to extinction in the proximity of the villages and they must travel further distances to hunt. Besides, for commercially interesting species such as elephants and gorillas, hunting distances are much larger because the returns are higher. Another interesting finding of this study is that mammal populations have also been reduced by hunting even within protected areas. 'Strategies to sustainably manage wild meat hunting in both protected and unprotected tropical ecosystems are urgently needed to avoid further defaunation,' she says. 'This includes monitoring hunting activities by increasing anti-poaching patrols and controlling overexploitation via law enforcement'. A. Benitez-Lopez*, R. Alkemade2,3, A. M. Schipper2, D. J. Ingram4, P. A. Verweij5, J. A. J. Eikelboom2,5,6, M. A. J. Huijbregts1, 2 . 2017. The impact of hunting on tropical mammal and bird populations. Science (accepted), April 14 2017 DOI: 10.1126/science.aaj1891 1Department of Environmental Science, Institute for Wetland and Water Research, Radboud University,The Netherlands2PBL, Netherlands Environmental Assessment Agency, The Hague, The Netherlands. 3Environmental Systems Analysis Group, Wageningen University & Research, The Netherlands 4School of Life Sciences, University of Sussex, UK. 5Energy and Resources group, Copernicus Institute of Sustainable Development, Utrecht University, 6Resource Ecology Group, Wageningen University & Research The Netherlands


News Article | April 24, 2017
Site: www.eurekalert.org

Two years ago, the Zika virus drew attention to microcephaly, a developmental disorder in which the brain and skull display inhibited growth. But there are other causes of microcephaly, such as congenital genetic diseases. Much is still unknown about brain development, but researchers at Utrecht University, in collaboration with their colleagues in Switzerland, have now new shed light on the molecules involved. The results of their research will be published in Nature Cell Biology.


News Article | April 27, 2017
Site: www.eurekalert.org

The synchronization of brainwaves among students during class reflects how much they like the class and each other, a team of neuroscientists has found. "How well our brainwaves sync up with those of another person appears to be a good predictor of how well we get along and how engaged we are," explains lead author Suzanne Dikker, a research scientist at New York University's Department of Psychology and Utrecht University in the Netherlands. "Overall, our findings suggest that brain-to-brain synchrony is a possible neural marker for everyday social interactions." In a departure from standard experimentation, the scientists followed a group of 12 high school students and their teacher for an entire semester and recorded their brain activity during their regular biology classes using portable electroencephalogram (EEG) technology. "The study offers a promising new method to investigate the neuroscience of group interactions," adds senior author David Poeppel, a professor in NYU's Department of Psychology and Center for Neural Science and director of the Max Planck Institute for Empirical Aesthetics in Frankfurt. Previous studies have typically measured single individuals or one-on-one interactions in highly controlled laboratory settings. By contrast, this work, appearing in the journal Current Biology, gauged dynamic social interactions in a complex group setting outside of the laboratory, shedding light on the role of brain synchrony in a more natural environment. The study also included University of Florida researchers Lu Wan, the co-lead author, and Mingzhou Ding. Using low-cost, portable brain recording equipment, the researchers compared the EEG readings of the students to each other and then explored the factors that might predict the level of synchronized brain activity between students with their self-reports on classroom engagement (e.g., students' appreciation ratings of different teaching styles and their day-to-day focus level) and measures of classroom social dynamics: Students were not only asked how much they liked each other and the teacher, but also reported on how much they liked group activities in general. Both classroom engagement and social dynamics have been shown to be critical for learning. The results showed a positive correlation between a student's ratings of the course and the student's brain synchrony with her classmates as a group--in other words, the more a student's brain waves were in sync with the those in the classroom as a whole, the more likely she was to give the course a favorable rating. Similarly, the greater the synchrony between an individual student and her classmates, the more likely they were to give positive ratings to the instructor's teaching style. The researchers also examined whether or not brain-to-brain synchrony reflected how much students like each other. To do this, students reported how personally close they were to other individuals in the class. Specifically, they found that pairs of students who felt closer to each other were more in sync during class, but only if they had interacted with each other face-to-face immediately before class. This suggests that having face-to-face interaction right before sharing an experience matters, the researchers conclude, even if you're not directly interacting during that experience (like watching a video). Finally, students who considered group activities important in their lives, exhibited higher synchrony with their classmates. The mechanism underpinning the observed brain-to-brain synchronization is likely to be shared attention, the authors posit, and this new approach provides a quantitative means to measure the factors that mediate social cohesion in groups. The research was supported by the National Science Foundation (1344285) and a Netherlands Organization for Scientific Research Award (275-89-018). A video capturing a portion of the procedure may be viewed here: https:/ (courtesy of Micah Schaffer); still images available upon request.


News Article | May 1, 2017
Site: www.newscientist.com

Glacier dying? Snow problem! At least that’s the theory behind a pioneering – and outlandish – attempt to save a landmark glacier in Switzerland. The idea is to create artificial snow and blow it over the Morteratsch glacier in Switzerland each summer, hoping it will protect the ice and eventually cause the glacier to regrow. “The major effect of the snow is reflection of sunlight,” says Johannes Oerlemans of Utrecht University in the Netherlands, who came up with the plan. Without this covering, the sunlight would begin to melt the ice, but “as long as there’s snow on top, the ice beneath is unaffected,” he told the annual meeting of the European Geosciences Union in Vienna, Austria, on 27 April. This would be the first large-scale attempt to do this anywhere in the world. Like many of its Alpine neighbours, Morteratsch is shrinking because of global warming.  It has retreated in length from 8.5 kilometres in 1860 to 6 kilometres today, and is losing 30 to 40 metres per year. Morteratsch is a huge tourist attraction and something of a national treasure because it is the only glacier with a “snout” that is easily accessible. “Locals claim it’s the only place you can reach a glacier from a wheelchair,” says Oerlemans. Eager to try and save their prize economic asset, people in the nearby town of Pontresina appealed to Oerlemans and local colleagues to come up with a plan to save Morteratsch. The locals had been inspired by stories that white fleece coverings on a smaller glacier called Diavolezzafirn had helped it to grow by up to 8 metres in 10 years. So the locals wondered if a similar scheme would restore Morteratsch, and commissioned Oerlemans to investigate. Looking at previous work showing that natural snow can help glaciers grow, he concluded that the glacier could regain up to 800 metres of length within 20 years if it had a covering. He worked out that just a few centimetres of artificial snow blown onto a 0.5 square kilometre plateau high up the glacier each summer could be enough to protect the ice beneath. “In principle, even the snout could grow back,” says Oerlemans. Oerlemans says it would take 4000 snow machines to do the job, producing snow by mixing air blasts with water, which cools down through expansion to create ice crystals. The hope is that the water can be “recycled” from small lakes of meltwater alongside the glacier. But first, a pilot project funded by the locals is under way. In the pilot, Oerleman and his collaborators will spend a season blowing snow onto a small, artificial glacier at the foot of Diavolezzafirn. “We have to carry the glacier through the summer,” he says. If it works, there are hopes that the Swiss government might provide the millions of Euros needed for the much larger scheme. “That would need nationwide involvement,” says Oerleman. But if it proved effective, it could inspire similar projects to save glaciers elsewhere in the world. “The problem with the Morteratsch study,” says Matthias Huss of the University of Freibourg, Switzerland, “is the same as with all of those claiming to save glaciers popping up before: They imply that we can take some engineering measures to cancel the negative effects of climate change. Indeed, we can do this, and we can do it quite efficiently – the method principally works. But the costs for only an incredibly small part of the total glacierized area of a mountain range are immense.”


News Article | April 19, 2017
Site: www.eurekalert.org

Neurons are the main cells in the nervous system. They process information by sending, receiving, and combining signals from around the brain and the body. All neurons have a cell body where molecules vital for its functioning and maintenance are produced. The axon, a long and slender extension that can reach one metre in length in humans, sends information from the nerve cell to other nerve cells. Neuronal survival is highly dependent on the transport of vital molecules within this axon. Research has shown that defects in the transport function in the axons play a key role in degenerative brain diseases such as Alzheimer. "Previous research examined transport processes in small areas of the axon, such as the very beginning or the very end. This left it unclear how the movement of molecules through the axon was regulated over long distances. In our study, we provide the first comprehensive map of transport in mammalian axons", says Casper Hoogenraad, Professor of Cell Biology at Utrecht University, explaining the relevance of this study. In most neurons, an area between the cell body and the axon called the 'axon initial segment' serves as a checkpoint: only some molecules can pass through it. This area has stumped scientists for more than a decade. Why should one type of molecule be able to pass through this area, while others cannot? The answer is to be found in the traffic regulator, a protein called MAP2. "With this discovery, we have answered a fundamental question about the unique functioning of nerve cells that has occupied scientists for a long time", lead author of the study Dr Laura Gumy says. The cell biologists from Utrecht first discovered that larger quantities of MAP2 accumulate between the cell body and the axon. When they removed MAP2 from the neuron, the normal pattern of molecule movement changed. Certain molecules suddenly ceased to enter the axon, whereas others accumulated in the axon instead of passing through to the cell body. This abnormal transport indicates that MAP2 is the driving force behind transport within the axon. The cell biologists from Utrecht University went on to make another very important discovery. Since axons are so long, transport in the neurons is carried out by sets of proteins - known as 'motor proteins' - that carry packages of other proteins on their back. As it turns out, MAP2 is able to switch a specific 'motor protein' on or off, like a car key. This means that MAP2 actually controls which packages of molecules may enter the axon and which may not. Targeting the activity of the transport engine allowed the researchers to make another interesting discovery: MAP2 is also able to control the delivery of molecules at specific points along the axon. "Transport within axons has been shown to fail in Alzheimer, Parkinson's disease and Huntington's disease, as well as in many other diseases. When the neuron is no longer able to control where molecules go, or is unable to get molecules to where they need to be, it cannot do its job. By understanding how transport works, we have laid the foundation for considering new targets and potential therapies for various neurodegenerative disorders", Casper Hoogenraad concludes.


News Article | May 3, 2017
Site: www.newscientist.com

The road to hell may be paved with good intentions, but at least there’s now a map to get you there. The map is the first to show the whereabouts of almost 100 massive remnants of what were once tectonic plates, but which long ago sank into the bowels of our planet through a process called subduction. “We’re pioneering the first map of the underworld,” says Wim Spakman of Utrecht University in the Netherlands, who unveiled plans to launch the atlas at the annual meeting of the European Geosciences Union in Vienna. “We will make our Atlas of the Underworld public for everyone to use, criticise and supplement with new data once our supporting work is published, which is imminent.” Knowing the positions of huge, ancient slab remnants could prove invaluable for geological research and exploration, says Spakman – and could bring us closer to forecasting earthquakes. So far, 98 slabs strewn throughout Earth’s upper and lower mantles have been mapped. Some are found at depths of 2900 kilometres, and with ages of up to 350 million years. All the slabs originated at or near Earth’s surface. Through collisions with other plates, or other tectonic activity, they all at some point began heading downwards, first through the upper mantle, then through the much more viscous lower mantle, which starts at around 660 kilometres down. Some have reached the outer core at 2900 kilometres. Spakman and his colleagues detected the positions and sizes of the plates through an echolocation technology called seismic tomography. The slabs conduct sound faster than surrounding magma, and so give a telltale seismic signature of their existence. The team combined their measurements with extensive pre-existing research on subducted slabs to corroborate and chart the geological history of each slab found. “We worked our way from the top, where we know and agree on the origins of slabs, to deeper, previously unknown ones,” says Spakman. “We’ve given them all a geographic name to make them easy to recognise.” For example, Spakman and his colleagues Douwe van Hinsbergen and Douwe van der Meer have used their data to explore the history of individual slabs, including one they have called the Aegean plate. This sank 120 million years ago below what is now the Aegean Sea, a key event in the formation of the Tethys Ocean that once separated Africa and Europe. Now, they are moving on to deeper slabs. “We’re looking into the early history of the Pacific Ocean around the ancient land mass of Pangea, and we’ve already found subduction remnants all around the present day Pacific, whose predecessor at the time was the Panthalassa Ocean,” says Spakman. “We can build much tighter connections between how tectonic plates moved around the globe in relation to what was going on in the mantle,” says Spakman. Until now, the main method of doing this has been to analyse ancient subducted rocks brought to the surface again by volcanic plumes. “Now, we can add new information about what once occurred through mapping the geological history of these subduction remnants,” he says. Knowing how subducted slabs might contribute to friction in the mantle could also help our understanding of and ability to forecast earthquakes, as well as how plate tectonics could raise sea level by raising the sea floor. “It could also help us find huge mineral deposits,” says Spakman. Other geologists are enthusiastic about the atlas. “Knowing where all the subducted oceanic crust has gone over the past 300 million years will allow us to play back the movie of plate tectonics in reverse,” says Steve Jacobsen of Northwestern University in Illinois. Jacobsen, who previously discovered evidence for massive water deposits in the deep mantle, says the atlas would also allow calculation of the amounts of water and carbon recycled by the planet over the past few million years. “Such a database would certainly be useful because plate tectonics ultimately controls most of what happens at Earth’s surface, from continent building and weathering rates to volcanism and much more,” says Matthew Dodd at University College London. “So knowing where ancient subduction zones were, how fast and old they were, will help geologists answer a plethora of scientific questions, including the long-term habitability of our planet through time, as well as natural resource exploration.” It might also help us study Earth’s origins, says Lydia Hallis at the University of Glasgow in the UK. “Information relating to the location of past and present subduction zones will help establish whether there are likely to be areas in the deep mantle that are totally unaffected by subduction, and hence maintain Earth’s original mantle composition,” she says. “These areas would provide the best targets for researchers studying Earth’s formation.”


News Article | April 17, 2017
Site: www.newscientist.com

Workplace exposure to electromagnetic fields is linked to a higher risk of developing the most common form of motor neurone disease. Amyotrophic lateral sclerosis (ALS) is a disease that ravages the body’s nerve cells, leaving people unable to control their bodies. People can die as soon as two years after first experiencing symptoms. “Several previous studies have found that electrical workers are at increased risk of ALS,” says Neil Pearce, at the London School of Hygiene and Tropical Medicine. “We don’t know why the risk is higher, but the two most likely explanations involve either electrical shocks, or ongoing exposure to extremely low frequency magnetic fields.” Now an analysis of data from more than 58,000 men and 6,500 women suggests it is the latter. Roel Vermeulen, at Utrecht University in the Netherlands, and his team found that people whose jobs exposed them to high levels of very low frequency magnetic fields were twice as likely to develop ALS as people who have never had this kind of occupational exposure. Jobs with relatively high levels of extremely low frequency electromagnetic fields include electric line installers, welders, sewing-machine operators, and aircraft pilots, says Vermeulen. “These are essentially jobs where workers are placed in close proximity to appliances that use a lot of electricity.” The team have stressed that this study is observational – it has not proven that the fields themselves cause ALS, just that this factor is linked to a person’s likelihood of developing the disease. However, it provides the best evidence yet that magnetic fields could be to blame for the disease. “This study has much better information on exposure to magnetic fields than previous studies,” says Pearce. “It shows that the increased risk of ALS in electrical workers is most likely due to magnetic field exposure, rather than to electrical shocks.” But Christian Holscher, at Lancaster University, UK, says the results should be interpreted with caution. “The effect of extremely low frequency magnetic fields on ALS development is not clear,” he says. The study only just crosses the threshold for statistical significance, and because only 82 people in the analysis developed the disease, the finding may well be a false positive, he says. “Motor neurone disease is a devastating and complex disease, and it is likely that a wide range of triggers, from environmental to genetic, will cause an individual to get the condition,” says Brian Dickie, of UK charity the Motor Neurone Disease Association. Read more: Microsoft app helps people with ALS speak using just their eyes


News Article | April 25, 2017
Site: phys.org

Physicists at Utrecht University have created a 'quantum simulator,' a model system to study theoretical prognoses for a whole new class of materials. These 'supermaterials' include graphene, which has a two-dimensional structure and unique characteristics. The experiments conducted in Utrecht not only confirm the theoretical physicists' predictions, but also provided new insights. They have discovered that at higher energy levels, a simple rectangular lattice has characteristics that are normally only observed in exotic materials. The results of their research are Published in Nature Physics of 24 April 2017.


News Article | April 24, 2017
Site: phys.org

Two years ago, the Zika virus drew attention to microcephaly, a developmental disorder in which the brain and skull display inhibited growth. But there are other causes of microcephaly, such as congenital genetic diseases. Much is still unknown about brain development, but researchers at Utrecht University, in collaboration with their colleagues in Switzerland, have now new shed light on the molecules involved. The results of their research will be published in Nature Cell Biology.


News Article | April 17, 2017
Site: www.newscientist.com

LIFE might eke out an existence far deeper inside Earth than we imagined. Samples from a mud volcano contain biological signatures that suggest microbes lived in the material when it was several kilometres beneath the ocean floor. “We might have a very big biosphere below our feet that’s very hard to get to,” says Oliver Plümper of Utrecht University in the Netherlands. Other researchers agree life could exist at such depths, but say the case is not yet proven. “They don’t have conclusive evidence,” says Rocco Mancinelli, an astrobiologist at NASA’s Ames Research Center, who studies life in extreme environments. “We might have a very big biosphere deep below our feet that’s very hard to get to” Plümper’s team studied 46 samples drilled from the South Chamorro mud volcano, near the deepest part of the ocean, the Mariana trench. Here, one tectonic plate slides under another. The heat and stress causes some of the material on the subducting plate to become a buoyant mineral called serpentinite that rises and erupts out of mud volcanoes. Examining the serpentinite in their samples, the team found chemicals usually produced by life, including amino acids and hydrocarbons. Given that some microbes can withstand temperatures as high as 122°C and pressures about 3000 times higher than at Earth’s surface, Plümper calculates that life could survive up to 10 kilometres beneath the seabed. There have been several recent reports of life at great depths, with nematode worms found living 3 kilometres down in a gold mine, for instance. But if Plümper is right, life can survive far deeper still. Mineral reactions at these depths would provide the carbon, nitrogen and energy life needs, says Mancinelli. But the chemicals found by Plümper’s team might have been produced by processes that don’t involve life, he adds. This article will appear in print under the headline “Life could exist up to 10 km below sea floor” Read more: Deep life: Strange creatures living far below our feet, Life is found in deepest layer of Earth’s crust


News Article | May 3, 2017
Site: www.eurekalert.org

VIDEO:  Extension of Continental, Marginal and Marine environments from ~18.4 to ~10.5 Ma showing the the two marine incursions reported in this study. view more A tiny shark tooth, part of a mantis shrimp and other microscopic marine organisms reveal that as the Andes rose, the Eastern Amazon sank twice, each time for less than a million years. Water from the Caribbean flooded the region from Venezuela to northwestern Brazil. These new findings by Smithsonian scientists and colleagues, published this week in Science Advances, fuel an ongoing controversy regarding the geologic history of the region. "Pollen records from oil wells in eastern Colombia and outcrops in northwestern Brazil clearly show two short-lived events in which ocean water from the Caribbean flooded what is now the northwest part of the Amazon basin," said Carlos Jaramillo, staff scientist at the Smithsonian Tropical Research Institute and lead author of the study. "Geologists disagree about the origins of the sediments in this area, but we provide clear evidence that they are of marine origin, and that the flooding events were fairly brief," Jaramillo said. His team dated the two flooding events to between 17 to18 million years ago and between 16 to 12 million years ago. Several controversial interpretations of the history of the region include the existence of a large, shallow sea covering the Amazon for millions of years, a freshwater megalake, shifting lowland rivers occasionally flooded by seawater, frequent seawater incusions, and a long-lived "para-marine metalake," which has no modern analog. Jaramillo assembled a diverse team from the Smithsonian and the University of Illinois at Urbana-Champaign; Corporacion Geologica Ares; the University of Birmingham; the University of Ghent; the Universidad del Norte, Baranquilla, Colombia; the University of Alberta, Edmonton; the University of Zurich; Ecopetrol, S.A.; Hocol, S.A.; the Royal Netherlands Institute for Sea Research at Utrecht University; the University of Texas of the Permian Basin; and the Naturalis Biodiversity Center. Together, they examined evidence including more than 50,000 individual pollen grains representing more than 900 pollen types from oil drilling cores from the Saltarin region of Colombia and found two distinct layers of marine pollen separated by layers of non-marine pollen types. They also found several fossils of marine organisms in the lower layer: a shark tooth and a mantis shrimp. "It's important to understand changes across the vast Amazonian landscape that had a profound effect, both on the evolution and distribution of life there and on the modern and ancient climates of the continent," Jaramillo said. The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a part of the Smithsonian Institution. The Institute furthers the understanding of tropical nature and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. STRI website: http://www. . C. Jaramillo, I. Romero, C. D'Apolito, J. Ortiz. "Miocene flooding events of western Amazonia." Science Advances. Manuscript Number: sciadv.1601693; Smithsonian Tropical Research Institute

Loading Utrecht University collaborators
Loading Utrecht University collaborators