Wildman R.A.,Quest University Canada |
Vernieu W.S.,U.S. Geological Survey
Lake and Reservoir Management | Year: 2017
Wildman RA Jr, Vernieu WS. 2017. Turbid releases from Glen Canyon Dam, Arizona, following rainfall-runoff events of September 2013. Lake Reserv Manage. 00:1–6. Glen Canyon Dam is a large dam on the Colorado River in Arizona. In September 2013, it released turbid water following intense thunderstorms in the surrounding area. Turbidity was >15 nephelometric turbidity units (NTU) for multiple days and >30 NTU at its peak. These unprecedented turbid releases impaired downstream fishing activity and motivated a rapid-response field excursion. At 5 locations upstream from the dam, temperature, specific conductance, dissolved oxygen, chlorophyll a, and turbidity were measured in vertical profiles. Local streamflow and rainfall records were retrieved, and turbidity and specific conductance data in dam releases were evaluated. Profiling was conducted to determine possible sources of turbidity from 3 tributaries nearest the dam, Navajo, Antelope, and Wahweap creeks, which entered Lake Powell as interflows during this study. We discuss 4 key conditions that must have been met for tributaries to influence turbidity of dam releases: tributary flows must have reached the dam, tributary flows must have been laden with sediment, inflow currents must have been near the depth of dam withdrawals, and the settling velocity of particles must have been slow. We isolate 2 key uncertainties that reservoir managers should resolve in future similar studies: the reach of tributary water into the reservoir thalweg and the distribution of particle size of suspended sediment. These uncertainties leave the source of the turbidity ambiguous, although an important role for Wahweap Creek is possible. The unique combination of limnological factors we describe implies that turbid releases at Glen Canyon Dam will continue to be rare. 2017 © Copyright by the North American Lake Management Society
Helfand D.J.,Columbia University |
Helfand D.J.,Quest University Canada |
White R.L.,US Space Telescope Science Institute |
Becker R.H.,University of California at Davis |
Becker R.H.,Lawrence Livermore National Laboratory
Astrophysical Journal | Year: 2015
The FIRST survey, begun over 20 years ago, provides the definitive high-resolution map of the radio sky. This Very Large Telescope (VLA) survey reaches a detection sensitivity of 1 mJy at 20 cm over a final footprint of 10,575 deg2 that is largely coincident with the Sloan Digital Sky Survey (SDSS) area. Both the images and a catalog containing 946,432 sources are available through the FIRST Web site (http://sundog.stsci.edu). We record here the authoritative survey history, including hardware and software changes that affect the catalog's reliability and completeness. In particular, we use recent observations taken with the JVLA to test various aspects of the survey data (astrometry, CLEAN bias, and the flux density scale). We describe a new, sophisticated algorithm for flagging potential sidelobes in this snapshot survey, and show that fewer than 10% of the cataloged objects are likely sidelobes, and that these are heavily concentrated at low flux densities and in the vicinity of bright sources, as expected. We also report a comparison of the survey with the NRAO VLA Sky Survey (NVSS), as well as a match of the FIRST catalog to the SDSS and Two Micron Sky Survey (2MASS) sky surveys. The NVSS match shows very good consistency in flux density scale and astrometry between the two surveys. The matches with 2MASS and SDSS indicate a systematic 10-20 mas astrometric error with respect to the optical reference frame in all VLA data that has disappeared with the advent of the JVLA. We demonstrate strikingly different behavior between the radio matches to stellar objects and to galaxies in the optical and IR surveys reflecting the different radio populations present over the flux density range 1-1000 mJy. As the radio flux density declines, stellar counterparts (quasars) get redder and fainter, while galaxies get brighter and have colors that initially redden but then turn bluer near the FIRST detection limit. Implications for future radio sky surveys are also briefly discussed. In particular, we show that for radio source identification at faint optical magnitudes, high angular resolution observations are essential, and cannot be sacrificed in exchange for high signal-to-noise data. The value of a JVLA survey as a complement to Square Kilometer Array precursor surveys is briefly discussed. © 2015. The American Astronomical Society. All rights reserved..
News Article | November 5, 2016
For the next few articles, I will be featuring interviews with female researchers in animal behaviour (from students to assistant professors), talking about a recent discovery they made. This week’s interview is with Kirsty Graham. Kirsty Graham is a PhD student at the University of St Andrews, Scotland, who works on gestural communication of chimpanzees and bonobos in Uganda and DRCongo. I recently asked her some questions about the work that she does and some exciting recent findings of hers about how these animals communicate. You can check out her personal blog here. Credit: Kirsty Graham How did you become interested in communication, and specifically gestures? Languages are fascinating – the diversity, the culture, the learning – and during undergrad, I became interested in the origins of our language ability. I went to Quest University Canada (a small liberal arts university) and learned that I could combine my love of languages and animals and being outdoors! Other great apes don’t have language in the way that humans do, but studying different aspects of communication, such as gestures, may reveal how language evolved. Although my interest really started from an interest in languages, once you get so deep into studying other species you become excited about their behaviour for its own sake. In the long run, it would be nice to piece together how language evolved, but for now I’m starting with a very small piece of the puzzle – bonobo gestures. How do you study gestures in non-human primates? There are a few different approaches to studying gestures: in the wild or in captivity; through observation or with experiments; studying one gesture in detail or looking at the whole repertoire. I chose to observe wild bonobos and look at their whole repertoire. Since not much is known about bonobo gestural communication, this seemed like a good starting point. During my PhD, I spent 12 months at Wamba (Kyoto University’s research site) in the DRCongo. I filmed the bonobos, anticipating the beginning of social interactions so that I could record the gestures that they use. Then I spent a long time watching the videos, finding gestures, and coding information about the gestures. What’s it like working out in the field with chimps and bonobos? Fieldwork is great! It can be pretty lonely sometimes and physically exhausting, but field observation is imperative for figuring out a species’ natural behaviour. Fieldwork and captive experiments complement one another. At Wamba, the bonobos are very well habituated, so we can observe them at a distance of 5-10m when they’re on the ground. I’m now at Kalinzu doing a pilot study on chimpanzees. Sometimes you have excellent days, where the apes are all travelling together, and sit and groom on a log in a clearing while all the infants are playing. Those are great data days. But sometimes you have a day where it rains and the apes spend all morning in their nests! It’s a mixed bag, but overall it’s a pretty fun job. I think I know what gestures are from when I communicate with people, but how can you decide what counts as a gesture for a non-human animal? A gesture is a body movement (arms, legs, head, torso) that is performed intentionally in order to communicate something to another individual. Bonobos raise their arms, flap their legs, shake their heads, thrust their hips, just to name a few gestures. There are silent-visual gestures like waving, audible gestures like clapping, and contact gestures like slapping someone on the back. A gesture should be directed towards another individual (no random arm flailing while sitting on your own); the signaller should check that the recipient is paying attention (what’s the point in waving at you if you’re facing the other way?) and select an appropriate gesture (e.g. a tap on the shoulder if the recipient is looking away); and if the recipient doesn’t respond to the gesture, the signaller should persist or elaborate. These criteria show that the signaller has a goal in mind, something that they want to communicate, and are using gestures to achieve that goal. What kinds of things do chimpanzees and bonobos gesture about? What have you learned from studying them? Chimpanzees use around seventy gesture types in the wild, and they produce gestures intentionally, aiming to affect the behaviour of the recipient. Chimpanzee gestures are used to request a variety of behaviour, from begging for food to requesting sex. But chimpanzees are not our only closest living relative – the bonobo is equally related to humans. Comparing the two species offers insight into how gesture evolved. My research so far has focused on the bonobo, trying to fill in this gap in our knowledge. We found that the bonobos at Wamba have a vocabulary of 68 gesture types. The overlap with published data for chimpanzees (at Budongo research site in Uganda) was roughly 90%. Such a large overlap points toward a genetically channelled repertoire of gestures – if the gestures were all individually learned, we would expect more differences between species and even between populations and individuals. The chimpanzee repertoire overlaps around 80% with orangutans and 60% with gorillas, and so it is likely that our last common ancestor used many of these gestures. Our study was the first to look at each individual’s “understood repertoire”, which is similar to what linguists would call a “receptive vocabulary” – the words that a person can understand, whether or not they ever use them. One can measure the “expressed repertoire” by seeing what gestures an individual deploys, but for the “understood repertoire”, one must see what gesture types the individual receives and responds to in a way that satisfies the signaller. This is also how I figure out what a gesture means – if Bonobo A does an “arm raise” gesture and Bonobo B responds by starting to groom the signaller, and Bonobo A seems satisfied with that response (i.e. they don’t keep gesturing), then the meaning of “arm raise” in this instance was “please groom me”. In that case, “arm raise” would be in Bonobo A’s expressed repertoire and Bonobo B’s understood repertoire. When we grouped bonobos by age or by sex, then each group had most gestures in their expressed and understood repertoire. For example, both males and females can both express and understand the gesture “Reach”. In fact, of the 47 gesture types that were seen more than three times, forty-two were both used and expressed by males and females, young and adult. Specific gestures are not being produced only by males and received only by females, or only by young and only by old, rather this is a mutually understood communication system in which all individuals have the potential to be both signaller and recipient for almost all gesture types. Language is also a communication system where any native speaker can have access to the same words as any other native speaker. This mutual understanding of signals is required to communicate about goals that anyone might want and anyone might give. For bonobos and chimpanzees, these activities include play, grooming, feeding, travelling together, and sex. At some point, it became necessary for our human ancestors to communicate about more than these immediate goals, and therein lies the mystery of language evolution. How similar are the chimpanzee and bonobo gestures to our own? What can your findings tell us about the evolution of human gestures? Good question! We don’t know exactly how many gestures humans share with chimpanzees and bonobos because we learn a lot of gestures alongside language. By the time infants are old enough to start using gestures, they are also learning words and conventional gestures of the culture that they’re growing up in. Observation of humans is therefore inadequate for seeing which gestures are shared with other apes. Byrne and Cochet wrote a neat paper, “Where have all the (ape) gestures gone?”, suggesting an experiment to test whether naïve human observers could understand other apes’ gestures. Our findings tell us that given the overlap of all great ape gestures, early humans likely also shared this gestural repertoire. Gestures are an important way for great apes to communicate, they use them to request food, grooming, and sex. But there are other aspects to communication as well, such as vocalisations and facial expressions. New research that looks at how great ape communication works across all of these modalities is necessary before we can start to answer the difficult questions of how language evolved. If these other forms of communication are sufficient for other species of great apes, then why language? Graham, K.E., Furuichi, T. & Byrne, R.W. (2016) The gestural repertoire of the wild bonobo (Pan paniscus): a mutually understood communication system. Animal Cognition doi:10.1007/s10071-016-1035-9 All photos were provided by Kirsty Graham, with permission.
Shields G.A.,University of Texas at Austin |
Bonning E.W.,Quest University Canada
Astrophysical Journal Letters | Year: 2013
Recent results indicate that the compact lenticular galaxy NGC 1277 in the Perseus Cluster contains a black hole of mass ∼1010 M ⊙. This far exceeds the expected mass of the central black hole in a galaxy of the modest dimensions of NGC 1277. We suggest that this giant black hole was ejected from the nearby giant galaxy NGC 1275 and subsequently captured by NGC 1277. The ejection was the result of gravitational radiation recoil when two large black holes merged following the merger of two giant ellipticals that helped to form NGC 1275. The black hole wandered in the cluster core until it was captured in a close encounter with NGC 1277. The migration of black holes in clusters may be a common occurrence. © 2013. The American Astronomical Society. All rights reserved.
Prud'homme-Genereux A.,Quest University Canada
American Biology Teacher | Year: 2013
"What is life?" This deceptively simple question lies at the heart of biology. In this activity, students work in groups to come up with their own definition using a set of prompting cards that differs for each team. In doing so, students gain an appreciation of the complexities of addressing this question. The activity takes approximately 60-90 minutes to complete, but students often discuss its implications for weeks afterward. This activity successfully engaged freshman undergraduate students and could easily be adapted to high school and even elementary school students. © 2013 by National Association of Biology Teachers.
Prud'Homme-Genereux A.,Quest University Canada
American Biology Teacher | Year: 2016
Freshman students are instructed to read a popular science book related to the topic of the course and produce an outline of the work. To achieve this, they must identify the author's thesis and the arguments brought forth in support of the thesis. This analysis is done for the whole book and is repeated for every chapter. This exercise develops the ability to grasp how experiments serve as evidence in scientific discourse. This gives students the tools to read popular science books critically. Given the ease of access to this type of resource, this assignment may develop lifelong skills for scientifically informed citizens. © 2016 National Association of Biology Teachers. All rights reserved.
Porritt L.A.,University of British Columbia |
Russell J.K.,University of British Columbia |
Quane S.L.,Quest University Canada
Earth and Planetary Science Letters | Year: 2012
Pele's tears are a well known curiosity commonly associated with low viscosity basaltic explosive eruptions. However, detailed studies of these pyroclasts are rare and, thus, there is no full explanation for their formation. These intriguing pyroclasts have smooth glassy surfaces, vesiculated interiors (~30%), and fluidal morphologies trending towards teardrops and then spheres as they decrease in size to <2. mm. Detailed characterisation of Pele's tears from the 1959 fire-fountaining eruption of Kilauea Iki has led to a reassessment of the mechanisms of magma disruption and fragmentation, timescales of relaxation, and cooling rates that are responsible for their formation. We conclude that the particle size distributions and vesicularities of Pele's tears are representative of the magma properties at the moment of explosive disruption. However, the morphology of these unique pyroclasts results from reshaping through viscous relaxation, driven by surface tension forces, on a time scale fast enough to compete with cooling times. © 2012 Elsevier B.V.
Bedore M.,Quest University Canada
Studies in Social Justice | Year: 2014
While food deserts create whole sets of tangible consequences for people living within them, the problem has yet to be the subject of much normative, in-depth evaluation as an urban political economy of food access. This paper provides a critical analysis of a specific food desert and its responses, drawing on a case study of the low-income, spatially segregated North End of the small city of Kingston, Ontario, Canada. The main thrust of the paper is that the food desert remains a useful yet underexplored phenomenon through which to reveal the complexities and tensions surrounding the treatment of "choice" in a classed society. Understood as an urban political economy of declining food access, the food desert phenomenon reveals capital's complex role in the promotion or violation of dignity through the urban geographies of acquiring food for oneself, family, or household. Through the data presented here, the article also argues for a collective pause among critical scholars to radicalize, rather than reject, the role of consumer choice in a more just food system, and for further normative engagement with urban landscapes of retail consolidation.
Wildman Jr. R.A.,Harvard University |
Wildman Jr. R.A.,Quest University Canada |
Forde N.A.,Quest University Canada
Journal of the American Water Resources Association | Year: 2012
The water of the Colorado River of the southwestern United States (U.S.) is presently used beyond its reliable supply, and the flow of this river is forecast to decrease significantly due to climate change. A recent interim report of the Colorado River Basin Water Supply and Demand Study is the first acknowledgment of these facts by U.S. federal water managers. In light of this new stance, we evaluate the current policy of adaptation to water shortages in the Colorado River Basin. We find that initial shortages will be borne only by the cities of Arizona and Nevada and farms in Arizona whereas the other Basin states have no incentive to reduce consumptive use. Furthermore, the development of a long-term plan is deferred until greater water scarcity exists. As a potential response to long-term water scarcity, we evaluate the viability of an interstate water market in the Colorado River Basin. We inform our analysis with newly available data from the Murray-Darling Basin of Australia, which has used interstate water trading to create vital flexibility during extreme aridity during recent years. We find that, despite substantial obstacles, an interstate water market is a compelling reform that could be used not only to adapt to increased water scarcity but also to preserve core elements of Colorado River Basin law. © 2012 American Water Resources Association.
Prud'homme-Genereux A.,Quest University Canada
American Biology Teacher | Year: 2010
Four inquiry-based laboratories are described that introduce students to the properties of human brain cells. These experiments require no technical equipment, are inexpensive and safe, and introduce students to genuine research using neuropsychological investigations as a means of studying the properties of brain cells. Students design and conduct an experiment using optical illusions to explore the activity and response of specific nerve cells of the visual system. Some of the successes and pitfalls of such an activity are discussed. © 2010 by National Association of Biology Teachers.