University of Colorado Boulder
University of Colorado Boulder
News Article | April 25, 2017
A recent report from the Wisconsin Institute for Law and Liberty attempts to compare student test score performance for the 2015-16 school year across Wisconsin’s public schools, charter schools, and private schools participating in one of the state’s voucher programs. Though it highlights important patterns in student test score performance, the report’s limited analyses fail to provide answers as to the relative effectiveness of school choice policies. Apples to Apples: The Definitive Look at School Test Scores in Milwaukee and Wisconsin was reviewed by Benjamin Shear of the University of Colorado Boulder. Comparing a single year’s test scores across school sectors that serve different student populations is inherently problematic. One fundamental problem of isolating variations in scores that might be attributed to school differences is that the analyses must adequately control for dissimilar student characteristics among those enrolled in the different schools. The report uses linear regression models that use school-level characteristics to attempt to adjust for these differences and make what the authors claim are “apples to apples” comparisons. Based on these analyses, the report concludes that choice and charter schools in Wisconsin are more effective than traditional public schools. Unfortunately, the limited nature of available data undermines any such causal conclusions. The inadequate and small number of school-level variables included in the regression models are not able to control for important confounding variables, most notably prior student achievement. Further, the use of aggregate percent-proficient metrics masks variation in performance across grade levels and makes the results sensitive to the (arbitrary) location of the proficiency cut scores. The report’s description of methods and results also includes some troubling inconsistencies. For example the report attempts to use a methodology known as “fixed effects” to analyze test score data in districts outside Milwaukee, but such a methodology is not possible with the data described in the report. Thus, concludes Professor Shear, while the report does present important descriptive statistics about test score performance in Wisconsin, it wrongly claims to provide answers for those interested in determining which schools or school choice policies in Wisconsin are most effective. Find the review by Benjamin Shear at: http://nepc.colorado.edu/thinktank/review-milwaukee-vouchers Find Apples to Apples: The Definitive Look at School Test Scores in Milwaukee and Wisconsin, by Will Flanders, published by the Wisconsin Institute for Law and Liberty, at: http://www.will-law.org/wp-content/uploads/2017/03/apples.pdf The National Education Policy Center (NEPC) Think Twice Think Tank Review Project (http://thinktankreview.org) provides the public, policymakers, and the press with timely, academically sound reviews of selected publications. The project is made possible in part by support provided by the Great Lakes Center for Education Research and Practice: http://www.greatlakescenter.org The National Education Policy Center (NEPC), housed at the University of Colorado Boulder School of Education, produces and disseminates high-quality, peer-reviewed research to inform education policy discussions. Visit us at: http://nepc.colorado.edu
News Article | April 24, 2017
Feeling heartbroken from a recent breakup? Just believing you're doing something to help yourself get over your ex can influence brain regions associated with emotional regulation and lessen the perception of pain.That's the takeaway from a new University of Colorado Boulder study that measured the neurological and behavioral impacts the placebo effect had on a group of recently broken-hearted volunteers.
News Article | April 25, 2017
Wind and precipitation play a crucial role in advancing or delaying the breeding cycles of North American tree swallows, according to the results of a new University of Colorado Boulder-led study. The research, which appears today in the journal Proceedings of the Royal Society B, sheds new light on how wet, windy weather can affect tree swallow nesting and underscores the importance of considering factors beyond temperature when examining how climate change might affect species' biological niche. Over the past decade and a half, the average egg hatching date for tree swallows -- a common migratory bird species that winters in temperate southern climates before nesting in the spring at sites across North America, including the sub-Arctic regions covered in the study -- has shifted earlier in the year by an average of six days. This change is similar to, but considerably greater than, changes seen in more southerly sites and until now has been believed to correlate with rising temperatures. However, when CU Boulder researchers tested how swallow nesting data from two different Alaskan sites corresponded with both daily and seasonal climate indicators like the number of windy days, days with measureable precipitation and average daily temperature, they found that windiness (or lack thereof) had the most consistent correlation with swallow breeding patterns over time. "We expected that temperature and precipitation would be much more strongly predictive than wind," said Daniel Doak, a professor in CU Boulder's Environmental Studies Program and the co-author of the new research. "The study demonstrates that fine-scale climate effects are important to consider when thinking about what's going to affect a species." The study developed as a result of a CU Boulder undergraduate's research efforts. Rachel Irons, then a junior in the Department of Ecology and Evolutionary Biology, received a UROP grant and worked with the Alaska Department of Fish and Game on a long-term tree swallow nesting study to fulfill her senior thesis requirements. "Swallow phenology in Alaska is shifting at twice the rate of the continental U.S.," said Irons, who is the lead author of the new paper. "I figured it was related to temperature, but I added in wind and precipitation measurements just to get the whole climate picture." The results showed that a long-term decline in windiness (and to a more variable extent, rain) in central Alaska over the past decade-plus correlated with the birds' earlier breeding much more strongly than temperature, indicating that wet, windy spring weather that may have delayed egg laying in the past is now less of an impediment for the swallows. The authors noted that while it is not necessarily surprising that wind and rain would affect an aerial foraging species like tree swallows, the findings emphasize the need to broaden the scope of consideration when making predictions about which climate mechanisms will influence population ecology. "This shows that our initial intuitions are not always good about what's going to impact these birds and their patterns," said Doak. Additional co-authors of the new study include Alexandra Rose of CU Boulder; April Harding Scurr and Tricia Blake of the Alaska Songbird Institute; and Julie Hagelin of the Alaska Department of Fish and Game.
News Article | May 25, 2017
The climbing community is buzzing with news that Mount Everest’s notorious Hillary Step, a nearly vertical rock face just below the summit, may have collapsed. On May 17 British climber Tim Mosedale posted on social media a photograph of a rock outcropping, saying: “It’s official—The Hillary Step is no more.” This reignited chatter from last year speculating that the 2015 Nepal earthquake, which killed about 9,000 people including 19 climbers on Everest, also altered the shape of that part of the mountain. But some Sherpas, including Ang Tshering Sherpa, president of the Nepal Mountaineering Association, told the BBC Mosedale is mistaken and the rocky feature is unchanged. Once thought to be impossible to scale, the Hillary Step—a rocky rise jutting out of a narrow ridge with steep drop-offs of thousands of feet on either side—is the unavoidable final technical challenge before reaching the top of the mountain. The rock feature is named after Sir Edmund Hillary; he and Nepalese Sherpa Tenzing Norgay were the first people known to have successfully summited Everest, in 1953. The step is part of history, says climber and geologist Ulyana Horodyskyj, who specializes in glaciology and earned her PhD at the University of Colorado Boulder. “That’s why it’s an interesting conversation to see if it has changed,” she explains. “That [feature] is—or was—seen as your last true test before reaching the top.” Horodyskyj attempted Everest in 2014, shortly before the mountain’s deadliest avalanche killed 16 Sherpas, including one of her team members. She made it as far as Everest Base Camp. Horodyskyj says Mosedale’s photo of the step looks like something is different from images taken in past years, but she cannot be certain without photos taken more precisely from the same angle. The high winds and altitude (some 28,000 feet, or 8,530 meters) make it too difficult for a helicopter to fly safely and confirm the change. She expects better images of the scene to surface in the coming days, as other climbers reach that stage of their ascent in the middle of the climbing season. Even with the perfect picture, however, the amount of snow on the step varies from year to year, making it tough to know for sure if—and when—the topography has truly changed. “It could have happened during the earthquake or after,” Horodyskyj says. “Sometimes things fall immediately, and sometimes they crack and then eventually fall off.” The 2015 climbing season was canceled after that year’s temblor, and 2016 brought too much snow to confirm whether rumors of an altered landscape had any basis, despite hundreds of climbers reaching the summit. (If the step had indeed collapsed, it would be a somewhat flatter ridge without a rock face. Climbers could still traverse it.) But Horodyskyj says a change or collapse involving the Hillary Step could be dangerous for climbers, because it could expose potentially unstable ground. Without the rock face, “maybe you get the impression that it’s safer” if the climb along the ridge to the summit was flatter, she says. “But it might not be stable yet. It’s still settling post-earthquake.” Melting snow could further expose wobbly terrain. Right now, Horodyskyj says, a snow ridge next to the Hillary Step diverts some climbers over the rocks, easing a dangerous climbing-season traffic bottleneck that often keeps mountaineers waiting in the cold—with dwindling oxygen supplies—to use the fixed ropes installed on the step. That snow might not be there in coming years, in part due to climate change, Horodyskyj says. Much of her research is on “black carbon”—sooty pollution that settles on snowy mountainsides and glaciers, reducing the surface’s reflectivity and accelerating melting by absorbing more sunlight. Because it is tough to get to the summit, she says she and her colleagues do not yet have enough samples to know what effect black carbon has at that altitude. She hopes to attempt another climb soon, but will not make it this season. Horodyskyj, an experienced mountaineer, outlines a number of geologic signs that would confirm the condition of the Hillary Step. “I’d be looking for evidence of fresh rock fractures, and looking at the color of rocks,” she says. “When rocks are exposed to the elements, they get weathered. But when you break rocks open, they are much fresher. That would be a great way to tell.” Further, she adds, the rocks might currently be under too much snow to study: “I guess the true story will come out once the snow reveals its secrets.”
News Article | May 23, 2017
LUXEMBOURG--(BUSINESS WIRE)--SES (Euronext Paris:SESG) (LuxX:SESG) today announced the successful integration of NASA’s Global-Scale Observations of the Limb and Disk (GOLD) hosted payload with SES-14. GOLD will employ an ultraviolet imaging spectrograph to measure densities and temperatures in the Earth’s thermosphere and ionosphere in response to Sun-Earth interaction. It is aimed at revolutionizing scientists’ understanding of this part of the space environment and its impacts on low Earth orbit satellite drag (a force acting opposite to the direction of motion, slowing the satellite), and ionospheric disruptions of communication and navigation transmissions. GOLD will take unprecedented images of the temperature and composition changes over a hemisphere. GOLD is a result of collaboration among several world-leading entities. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is providing overall NASA program management, while the University of Central Florida’s Florida Space Institute is the Principal Investigator for the project. The GOLD instrument was built and will be operated by the University of Colorado Boulder Laboratory for Atmospheric and Space Physics. Satellite operator SES and its fully-owned subsidiary SES Government Solutions are providing the host satellite, mission operations, and science data transport. The project was developed in close partnership with Airbus Defence and Space, the company which is building the SES-14 spacecraft for SES. SES Government Solutions is exclusively focused on meeting the satellite communications needs of the U.S. Government and its agencies. Leveraging more than four decades of experience in the government SATCOM market, SES Government Solutions offers robust and secure end-to-end satellite communications solutions. “Using a host satellite makes access to space quicker and more cost efficient, while meeting the increasingly more sophisticated needs governments have nowadays. SES has extensive experience in hosted payload projects and is well-suited to meet these needs,” said Pete Hoene, President and CEO of SES Government Solutions. “We are very excited about hosting GOLD, and looking forward to it starting its important mission in space.” Testing and preparation of SES-14 and GOLD are on-going in Toulouse, France, in anticipation of a late 2017 launch on a SpaceX Falcon 9 from Kennedy Space Center in Cape Canaveral, Florida. The SES-14 satellite will provide coverage of the Americas, Atlantic Ocean, Western Europe, and Northwest Africa with High Throughput Satellite (HTS) services and Ku-band & C-band wide beam services. The wide beams will serve growing video neighborhoods in the Americas and also support existing VSAT services. The HTS Ku-band multi-spot beams will serve traffic-intensive data applications such as mobile backhaul, maritime and aeronautical services. SES white papers are available under https://www.ses.com/news/whitepapers SES is the world-leading satellite operator and the first to deliver a differentiated and scalable GEO-MEO offering worldwide, with more than 50 satellites in Geostationary Earth Orbit (GEO) and 12 in Medium Earth Orbit (MEO). SES focuses on value-added, end-to-end solutions in two key business units: SES Video and SES Networks. The company provides satellite communications services to broadcasters, content and internet service providers, mobile and fixed network operators, governments and institutions. SES’s portfolio includes the ASTRA satellite system, which has the largest Direct-to-Home (DTH) television reach in Europe, O3b Networks, a global managed data communications service provider, and MX1, a leading media service provider that offers a full suite of innovative digital video and media services. Further information available at: www.ses.com
News Article | May 27, 2017
--Lake County High School sophomores Ariel Benney and Bianca Gonzalez, and Abigail Reigel are the recipients of this year's High Mountain Institute (HMI) (http://www.hminet.org/)merit scholarships.Benney, daughter of Mr. & Mrs. Charles & Suzi Benney, will attend HMI this summer, Gonzales, daughter of Mr. & Mrs. Alberto & Vianca Gonzales, will attend HMI for the fall semester; Reigel, daughter of Mr. & Mrs. Michael & Allison Reigel will attend in the spring. With an extremely competitive admissions year at HMI, these LCHS scholarship recipients were selected for their commitment to academics, leadership, and involvement in their greater communities.The merit scholarships cover the full cost of tuition for each recipient, a $29,263 value for the HMI Semester, and a $8,650 value for the HMI Summer Term.Since inception in 1998, 31 other LCHS students have attended HMI on full merit scholarships. Past LCHS HMI Alumni have attended colleges such as University of Denver, University of Colorado Boulder, and Colorado State University.The High Mountain Institute is a semester-long boarding school for high school juniors. Each semester a new cohort of 48 students travel to Leadville from all over the country to partake in the school's rigorous academic curriculum, extended backpacking expeditions, and a small, intentional community.In addition to the semester program, HMI offers a 5-week Summer Term ( http://www.hminet.org/ summer-term/ about ) for high schoolers, a two week backpacking trip for middle schoolers, and a variety of adult programs including wilderness medicine and avalanche awareness training. HMI also partners with the local non-profit Full Circle of Lake County each summer to offer a free, week-long backpacking program for LCHS 7th and 8th graders.
News Article | May 23, 2017
They’re the most massive mates in the universe — and we have found more of them. Astronomers have raised the number of known pairs of supermassive black holes by about 50 per cent, thanks to a clever new way to sift through existing data. It’s a crucial step towards discovering how supermassive black holes became, well, supermassive. At present, that recipe calls for colossal collisions, but many questions remain. When two galaxies collide, their central supermassive black holes fall into the middle of the newly formed galaxy. There, they circle each other in a treacherous tango, hurtling closer and closer until they eventually merge into a single, even bigger, supermassive black hole. But that newly formed monster isn’t simply a combination of the two ancestors (minus some of the energy carried away in the collision). The coming together also stirs up a huge amount of gas and dust that feeds the central supermassive black holes as they spiral inward, sparking a pair of so-called active galactic nuclei (AGNs) and leading to a much heavier final entity. But by how much? To find out, astronomers have been on the hunt for these deadly duos – known as dual AGNs – for several years. But they haven’t previously been able to spot them, with the nine dual AGNs detected so far found by chance. “Our model of the universe tells us they should be there, but we have failed miserably to find them,” says Sara Ellison at the University of Victoria in Canada. Ellison and her colleagues have now pored through data from two sky surveys to find AGNs that look like they’re the result of a recent collision and simultaneously shine in the infrared part of the spectrum, a hint that there is a lot of dust. Using this technique, they found five new examples of dual AGNs. Not only does this increase the known population by 50 per cent, but it also paves the way towards a better understanding of how supermassive black holes grow, says David Rosario at Durham University in the UK. While Rosario is looking forward to detecting large numbers of these dual AGNs, Julie Comerford at the University of Colorado Boulder is particularly excited to study single examples in detail. Follow-up observations can show how the gas and dust flows into both individual supermassive black holes and help astronomers create a thorough picture of the growth spurt. Gravitational wave watchers in the far future should keep an eye on the galaxies hosting these dual AGNs too – they will be the sites of colossal crashes in tens of millions of years. Read more: Astrophile: Dancing black holes near their grand finale
News Article | May 11, 2017
Glaciers around the world are disappearing before our eyes, and the implications for people are wide-ranging and troubling, Twila Moon, a glacier expert at the University of Colorado Boulder, concludes in a Perspectives piece in the journal Science today. The melting of glacial ice contributes to sea-level rise, which threatens to "displace millions of people within the lifetime of many of today's children," Moon writes. Glaciers also serve up fresh water to communities around the world, are integral to the planet's weather and climate systems, and they are "unique landscapes for contemplation or exploration." And they're shrinking, fast, writes Moon, who returned to the National Snow and Ice Data Center this month after two years away. Her analysis, "Saying goodbye to glaciers," is published in the May 12 issue of Science. Moon admits she was pretty giddy when an editor at Science reached out to her to write a perspective piece on the state of the world's glaciers, because of her research knowledge and extensive publication record. "There was some serious jumping up and down," Moon says. "I thought, 'I've made it!' Their invitation was an exciting recognition of my hard work and expertise." But the topic, itself, is far from a happy one. Moon describes the many ways researchers study glacier dynamics, from in-place measurements on the ice to satellite-based monitoring campaigns to models. And she describes sobering trends: The projection that Switzerland will lose more than half of its small glaciers in the next 25 years; the substantial retreat of glaciers from the Antarctic, Patagonia, the Himalayas, Greenland and the Arctic; the disappearance of iconic glaciers in Glacier National Park, Montana, or reduction to chunks of ice that no longer move (by definition, a glacier must be massive enough to move). In her piece, Moon calls for continued diligence by the scientific community, where ice research is already becoming a priority. Moon says she got hooked on glaciers as an undergraduate in geological and environmental sciences at Stanford University, when she spent a semester abroad in Nepal. "For the first time I saw a big valley glacier, flowing through the Himalaya," she said, "and I thought it was about the coolest thing ever. After studying geology, the movement and sound of the ice, right now, made it feel almost alive.'" That experience kicked off a research career that has taken Moon to Greenland, Alaska, Norway, and to conferences around the world. She began her work "merely" as a geologist and glaciologist, interested in ice itself, Moon said. Only later did the influence of climate change come to play in her work. "I think I'm about as young as you can get for being a person who started in glaciology at a time when climate change was not a primary part of the conversation," says Moon, who is 35. She is consistently sought out by journalists hoping to understand Earth's ice, and she's sought out in the scientific community as well, recognized as someone who likes to collaborate across disciplinary boundaries. She recently worked with a biologist in Washington, for example, on a paper about how narwhals use glacial fronts in summertime--the tusked marine mammals appear to be attracted to glaciers with thick ice fronts and freshwater melt that's low in silt, though it's not yet clear why. After a couple of post-doctoral research years, at the National Snow and Ice Data Center and then the University of Oregon, Moon and her husband headed to Bristol, England, where she took a faculty position at the University of Bristol's School of Geographical Sciences. When it became clear that her husband's work wouldn't transfer, the two determined to head back to the Rocky Mountains. Moon started back as a researcher at CU Boulder's National Snow and Ice Data Center, part of CIRES, May 1. Twila Moon, CIRES scientist in the National Snow and Ice Data Center, 406-579-3088
News Article | May 9, 2017
Each night before “Greg” goes to bed he brushes and flosses his teeth. Then he double-checks the instructions on the dark brown bottle his nurse gave him before he unscrews the cap and tips five drops of a light-amber, oily liquid onto a spoon. The brew, glistening from the light of the bathroom fixture, is tasteless and has no odor he can detect. But it’s chock-full of bacteria. He sloshes the substance around in his mouth and swallows. Greg hopes that while he sleeps the foreign microbes will wage war with other organisms in his gut, changing that environment to ultimately help him manage some of the post-traumatic stress disorder (PTSD) symptoms that cloud his mind and riddle his days and nights with nightmares, flashbacks, thoughts of suicide and irrational responses to stressful events. The bacteria he is swallowing, his doctors tell him, “may help reduce symptoms of stress.” Each drop of Greg's brew is filled with millions of Lactobacillus reuteri, a bacterium isolated and derived from human breast milk. The Denver VA Hospital orders the substance and prescribes it as part of a PTSD clinical trial involving 40 veterans who either receive the bacteria or a placebo mix of sunflower oil and other inactive substances. (The bacterium is also currently used to treat a dental condition called chronic periodontitis because it has been shown to help fight inflammation.) Altering the immune system to help build resilience to stressful events is a roundabout way to fight PTSD. But despite the massive burden of this disorder, there are few treatments for many of its crushing symptoms. Of the more than two million troops deployed in U.S. military conflicts worldwide, an estimated 11 to 23 percent have sustained some level of either traumatic brain injury (TBI) or PTSD. Greg, whose name has been changed in this article to protect his identity, is among them. He served in Operation Iraqi Freedom and was injured when the vehicle he was in detonated a roadside improvised explosive device—killing several of his comrades and leaving him with a badly wounded leg, a traumatic brain injury and the constellation of symptoms that comprise PTSD. With few options available after he tried a variety of mental health therapies, last year he and 39 other veteran volunteers—all suffering from PTSD and being treated at the Rocky Mountain MIRECC for Veteran Suicide Prevention center in Denver—volunteered to be part of an early clinical trial to determine if L. reuteri can reduce their physiological and psychological responses to stressful situations. The roughly $200,000 trial is funded by the Department of Veterans Affairs and aimed at evaluating the feasibility, acceptability, tolerability and safety measures for the possible use of the bacterium to treat PTSD. The bacterium was chosen after earlier animal trials suggested it produced anxiety-fighting responses. Last year a team of researchers at the University of Colorado Boulder found that injecting beneficial bacteria into mice helped them become more resilient to the stress of residing with much larger, aggressive mice. In that study the scientists injected healthy mice with a heat-killed preparation of Mycobacterium vaccae—which, like L. reuteri, acts like a drug, modulating the mouse’s immune system. (The two microbes are cousins and share a common ancestor.) The injected mice exhibited less anxiety or fearlike behaviors, and behaved more proactively around their aggressors than did those in a control group, which had to make do without the shots. The vaccinated mice’s amplified calm made sense biochemically: The researchers discovered that the gut-altered mice also had more Tph2, an enzyme involved in the biosynthesis of the calming neurotransmitter serotonin, in the brain. The bacterial brew provided another benefit in the gut as well: Biopsies showed the injected mice were 50 percent less likely to suffer stress-induced colitis, as measured by cellular damage to the colon; and they had less system-wide inflammation. That study was hailed as a major breakthrough and named among the top 10 advancements and breakthroughs of 2016 by the nation’s leading nongovernmental funder of mental health research, the Brain and Behavior Research Foundation. “There is a growing recognition that the microbiome can impact health in general and, more specifically, mental health,” clinician Jeffrey Borenstein, the organization’s president, said in a statement about the research. The mouse work “can potentially be a game changer in our understanding of this, and ultimately lead to new treatments,” he added. “Our study in PNAS showed we can prevent a PTSD-like syndrome in mice,” says Christopher Lowry, a professor in the Department of Integrative Physiology at C.U.–Boulder, who headed up the study on mice that demonstrated M. vaccae’s effects on stress resilience. Lowry’s results were also consistent with earlier evidence about the powers of M. vaccae bacteria: Previous work established that M. vaccae increases serotonin in the prefrontal cortex, an area of the brain that modulates anxiety. (The researchers are not using M. vaccae in humans because it is not yet approved for human use whereas L. reuteri works along the same immune-regulating pathway and could be tapped without needing further regulatory approvals.) The human trials with L. reuteri began in August 2016 at the Denver VA Hospital, headed up by Lowry and Lisa Brenner, a psychiatry professor at the University of Colorado Denver School of Medicine. In addition to asking veterans to down a daily allotment of bacteria or placebo—the volunteers are unaware of which substance they are taking—each participant has been asked to keep a diary of gastrointestinal symptoms for about two weeks, and submit to stool tests. Participants then return for further blood tests covering various biomarkers of inflammation and gut permeability. Then, after eight weeks, the veterans are subjected to stress testing like the mice. Instead of exposing them to large mice, however, they are asked to do something even more intimidating to many humans: give a speech in front of a group while researchers collect their psychological and physiological stress measures (including heart rate variability and galvanic skin response). Participants also receive final blood and stool tests for biomarkers of inflammation, gut permeability and any changes in the microbiome. Final results from the study are expected in May 2018. The foundational work behind this study is “very provocative” because it validates the concept of immunizing against a variety of stress-related disorders, says John Cryan, head of the Department of Anatomy and Neuroscience at University College Cork in Ireland, who was not involved with the work. The findings, he says, suggest this may be a promising way to help fight anxiety in PTSD patients.
News Article | May 11, 2017
The Seismological Society of America (SSA) will present its highest honor, the 2017 Harry Fielding Reid Medal, to U.S. Geological Survey emeritus geologist George Plafker, for his transformative work on megathrust earthquakes in subduction zones, places where two tectonic plates meet, with one riding over the top of the other. Plafker will receive the Reid Medal at Seismology of the Americas, a joint meeting of the SSA and the Latin American and Caribbean Seismological Commission (LACSC), to be held 23-26 April 2018 in San Juan, Puerto Rico. Plafker and his colleagues did painstaking fieldwork after the magnitude 9.2 Alaskan earthquake in 1964, covering hundreds of kilometers of Alaskan shoreline in small boats, helicopters, and float-equipped aircraft. His research after the 1964 quake helped to launch a new field of megathrust earthquake geology, which used observations of the placement of intertidal organisms such as acorn barnacles, mussels and rockweed to determine the amounts of vertical change in land relative to sea level near subduction zones. Plafker and his colleagues determined that the massive Alaskan quake was caused by rupture along a deeply buried fault in a subduction zone where the Pacific tectonic plate thrusts below the North American plate. Earlier accounts of the Alaskan earthquake had suggested that the quake took place as slip along a vertical fault, as the Pacific plate rotated counter-clockwise against the North American plate. Plafker's work on the Alaska earthquake led to a re-examination of the 1960 magnitude 9.5 Chilean earthquake, the largest in recorded history, eight years later. After studying more than 1000 kilometers of mainland coast and islands of the Archipiélago de los Chonos in southern Chile, he and his colleagues concluded that the 1960 earthquake was also caused by megathrust faulting at a subduction zone, rather than slip along a vertical fault as previously thought. Megathrust earthquakes include the largest magnitude earthquakes seen on Earth, and often have devastating effects on coastal communities around the globe. "He is the one field geologist whose fieldwork contributed to the essence of plate tectonics, and specifically to subduction," said Peter Molnar, a professor of geological sciences at University of Colorado Boulder, in his commendation of Plafker. In his explorations, Plafker moved beyond his primary geological mapping research in southern Alaska to search for other geological evidence of tectonic deformation, including mapping active faults and studying ancient peat deposits that extended the megathrust record back in time. These paleoseismic studies within the 1964 rupture zone identified a total of nine giant seismic events in Alaska within the past 6500 years. His study of historic active faults and paleoseismicity in Alaska remains the basis for all seismic hazard maps in the state today. In his nomination for the Medal, Plafker's colleagues noted that his thorough and imaginative research has had an impact from earthquake engineering to popular writing about earthquakes and tsunamis. His work on the Alaskan and Chilean earthquakes transformed ideas about the long history of massive earthquakes at subduction zones, highlighting the potential seismic risk of key regions such as the Cascadia subduction zone off the west coast of the United States and Canada. Plafker received his B.S. in geology from Brooklyn College in 1949, his master's degree in geology from the University of California, Berkeley in 1956 and his Ph.D. in geology and geophysics from Stanford University in 1972. He has worked as an engineering geologist from the U.S. Army Corps of Engineers, a geologist for the USGS, and a petroleum geologist for Chevron. In 1979 Plafker received the U.S. Department of the Interior Distinguished Service Award, the highest award that can be granted to a career employee within the Department of the Interior. First awarded in 1975, the Medal recognizes outstanding contributions in seismology and earthquake engineering. Harry Fielding Reid, a pioneering American seismologist, was in 1906 the first to propose the elastic-rebound theory, concerning the buildup and release of stress and strain around faults as a cause of earthquakes. The call for nominations for next year's Medal, along with a list of past winners, is available at the Seismological Society of America's website. The Seismological Society of America is a scientific society devoted to the advancement of earthquake science. Founded in 1906 in San Francisco, the Society now has members throughout the world representing a variety of technical interests: seismologists and other geophysicists, geologists, engineers, insurers, and policy-makers in preparedness and safety.