Commentary: Polar Science and Social Purpose

... In 1986, I participated in a review of polar science in Canada that resulted in the publication of Canada and Polar Science (Roots, E.F., et al., 1987, report to the Minister of Indian and Northern Affairs, Ottawa K1A 0H4). ... This year, I was able to survey polar researchers in Canadian universities to determine whether, from their point of view, the findings described in Canada and Polar Science had become dated. In doing this, I gained the impression that there have been some changes in this matter of "relevant" northern research. These are some of my impressions; the results of my survey appear in Canada and Polar Science Revisited (Adams, W.P., 1992, Canadian Polar Commission, Suite 1710, 360 Albert Street, Ottawa K1R 7X7). First, insofar as it can be used as a measure of "relevant" science, there appears to have been some increase in social science research in the North and some gain in confidence among social researchers working there. ... Another interesting development since 1986 has been the way in which the term "global change" has captured the imaginations of a wide cross-section of the public and researchers. ... The increased public acceptance of the "relevance" of global change research appears to be particularly marked among northern residents. Ozone depletion, greenhouse warming, atmospheric and ocean pollution, and the focusing of contaminants at key points in the food chain are all examples of environmental degradation that have particularly serious implications for those who live at high latitudes. ... Also, since 1986, devolution of power to the territories has put various aspects of the management of research into the control of northerners. ... Although less marked than some of the other changes that I have tried to describe, it is my impression that university researchers are now more interested in "aboriginal science." This is a matter of very special cultural significance in terms of the involvement of native northerners in research. It is a matter about which there is a feeling of urgency in the North, as many feel that the generation that has the distinctive aboriginal view of the universe and that has the local ecological knowledge is passing. In my survey, I heard of a number of cooperative social and environmental projects that involve both Western and aboriginal science. ..

Bases for Field Research in Arctic and Subarctic Canada

There are more than 50 field stations in northern Canada. These are operated by governments, universities and private agencies. Although many have a particular disciplinary bias, such as marine science, meteorology, native studies, archaeology, limnology, glaciology or biology, most are available to all researchers as a base of operations. Approximately half of the stations are in the Northwest Territories, the remainder in the Yukon and northern parts of the provinces. A table is provided indicating seasonal availability, particular research emphases, level of services provided, accommodation available and ownership. There is no user charge at some stations; most levy a daily fee. The highest cost in 1987 was just over $200 (food and accommodation) per day for the station on the Ice Island, then located northwest of Axel Heiberg. The paper also contains mention of 25 circumpolar stations outside Canada and a bibliography.Key words: field stations, Arctic, Subarctic, Canada, circumpolar NorthMots clés: stations de recherche, Grand Nord canadien, recherche scientifique, stations circumpolaire

Fritz Müller, 1926-1980

... Fritz first came to the Arctic Institute in 1955 .... He came as a McGill-Carnegie Arctic Research Scholar to undertake the study of pingos, which form the basis of his doctoral dissertation and of the definitive publications on pingos, which were his first major scientific contributions. ... After two very full field expeditions to the Mackenzie Delta and Greenland in connection with the pingo work, Fritz left the Arctic Institute and McGill to accompany the successful Swiss Everest Expedition of 1956. ... Fritz climbed to the 8200-m level, taking the opportunity to extend his studies of patterned ground, begun in Greenland, to levels close to 8000 m in the South Col. ... In 1959, Fritz returned to Canada as a Research Associate at McGill and as leader of the Jacobson-McGill Arctic Research Expedition to Axel Heiberg Island, which has effectively operated ever since. Fritz himself was in the field in the Arctic Islands for eighteen field seasons during the last two decades. ... Although Fritz left Canada in 1970 to become head of the Department of Geography at the Swiss Federal Institute of Technology (ETH) in Zürich, he maintained an expedition office and the title of Honorary Professor at McGill for the remainder of his life. ... [During the Seventies, he was extensively involved] in the North Water Project, a study of the relatively ice-free areas between Devon and Ellesmere islands and Greenland, and its surrounding land and ice masses. ... In addition to his roles as leader of the Axel Heiberg and North Water projects, he set up glaciological teaching and research programs at McGill and ETH, ... [and chaired a number of committees of a number of international organizations across Canada, Germany, Switzerland and the United States.] ... We are pleased to report that the Government of the Northwest Territories has officially re-named the ice cap in central Axel Heiberg Island (70 47 N, 91 30 W) as the Müller Ice Cap, in his memory

Identification and Vetting of Ground Ambulance Providers to Support Air Medical Operations at STAT MedEvac

Timely medical transportation at an appropriate level of care is essential to achieve positive health outcomes in critical medical situations. Critical care transport programs, such as STAT MedEvac (STAT), often provide the highest level of care and the fastest mode of transport when patients need it most. Issues arise, however, when weather and other operational challenges make it unsafe or impractical to operate an air ambulance. STAT addresses this challenge by collaborating with ground ambulance agencies local to their air medical bases. The ground ambulance agency provides an ambulance and driver while STAT provides the medical crew and most of the required medical equipment to facilitate ground critical care transports. Although STAT currently vets ground ambulance agencies prior to utilizing them, this vetting process is limited and there have been potentially preventable operational and safety events. Additionally, STAT’s Communications Specialists frequently experience challenges in rapidly identifying an appropriate and available ground ambulance for these transports. This essay discusses the current state of STAT MedEvac’s Ground Partner Program, the development of a comprehensive vetting program, and the utilization of information gathered during the vetting process to streamline ground ambulance dispatching. This project is of public health importance because air and ground critical care services improve patient outcomes and facilitate rapid access to regionalized specialty care that is often unavailable locally

An overview of the Riemannian metrics on spaces of curves using the Hamiltonian approach

Here shape space is either the manifold of simple closed smooth unparameterized curves in $\mathbb R^2$ or is the orbifold of immersions from $S^1$ to $\mathbb R^2$ modulo the group of diffeomorphisms of $S^1$. We investige several Riemannian metrics on shape space: $L^2$-metrics weighted by expressions in length and curvature. These include a scale invariant metric and a Wasserstein type metric which is sandwiched between two length-weighted metrics. Sobolev metrics of order $n$ on curves are described. Here the horizontal projection of a tangent field is given by a pseudo-differential operator. Finally the metric induced from the Sobolev metric on the group of diffeomorphisms on $\mathbb R^2$is treated. Although the quotient metrics are all given by pseudo-differential operators, their inverses are given by convolution with smooth kernels. We are able to prove local existence and uniqueness of solution to the geodesic equation for both kinds of Sobolev metrics. We are interested in all conserved quantities, so the paper starts with the Hamiltonian setting and computes conserved momenta and geodesics in general on the space of immersions. For each metric we compute the geodesic equation on shape space. In the end we sketch in some examples the differences between these metrics.Comment: 46 pages, some misprints correcte

Reaction Mechanism and Water/Rock Ratios Involved in Epidosite Alteration of the Oceanic Crust

Epidosites are a prominent type of subseafloor hydrothermal alteration of basalts in ophiolites and greenstone belts, showing an end-member mineral assemblage of epidote + quartz + titanite + Fe-oxide. Epidosites are known to form within crustal-scale upflow zones and their fluids have been proposed as deep equivalents of black-smoker seafloor vent fluids. Proposals of the mass of fluid per mass of rock (W/R ratio) needed to form epidosites are contradictory, varying from 20 (Sr isotopes) to > 1,000 (Mg mobility). To test these proposals we have conducted a petrographic, geochemical and reactive-transport numerical simulation study of the chemical reaction that generates km3-size epidosite zones within the lavas and sheeted dike complex of the Samail ophiolite, Oman. At 250–400°C the modeled epidosite-forming fluid has near-neutral pH (∼ 5.2), high fO2, low sulfur and very low Fe (10−6 mol/kg) contents. These features argue against a genetic link with black-smoker fluids. Chemical buffering by the epidosite fluid enriches the precursor spilites in Ca and depletes them in Na and Mg. Completion of the spilite-to-epidosite reaction requires enormous W/R ratios of 700–∼40,000, depending on initial Mg content and temperature. Collectively, the variably altered rocks in the Samail epidosite zones record flow of ∼1015 kg of fluid through each km3 of precursor spilite rock. This fluid imposed on the epidosite an Sr-isotope signature inherited from the previous rock-buffered chemical evolution of the fluid through the oceanic crust, thereby explaining the apparently contradictory low W/R ratios based on Sr isotopes

THE "FREELY" FALLING TWO-LEVEL ATOM IN A RUNNING LASER WAVE

The time evolution of a two-level atom which is simultaneously exposed to the field of a running laser wave and a homogeneous gravitational field is studied. The result of the coupled dynamics of internal transitions and center-of-mass motion is worked out exactly. Neglecting spontaneous emission and performing the rotating wave approximation we derive the complete time evolution operator in an algebraical way by using commutation relations. The result is discussed with respect to the physical implications. In particular the long time and short time behaviour is physically analyzed in detail. The breakdown of the Magnus perturbation expansion is shown.Comment: 14 Pages, Late

Phylogeny, diversification, and biogeography of a hemiclonal hybrid system of native Australian freshwater fishes (Gobiiformes:Gobioidei: Eleotridae: Hypseleotris)

BACKGROUND: Carp gudgeons (genus Hypseleotris) are a prominent part of the Australian freshwater fish fauna, with species distributed around the western, northern, and eastern reaches of the continent. We infer a calibrated phylogeny of the genus based on nuclear ultraconserved element (UCE) sequences and using Bayesian estimation of divergence times, and use this phylogeny to investigate geographic patterns of diversification with GeoSSE. The southeastern species have hybridized to form hemiclonal lineages, and we also resolve relationships of hemiclones and compare their phylogenetic placement in the UCE phylogeny with a hypothesis based on complete mitochondrial genomes. We then use phased SNPs extracted from the UCE sequences for population structure analysis among the southeastern species and hemiclones. RESULTS: Hypseleotris cyprinoides, a widespread euryhaline species known from throughout the Indo-Pacific, is resolved outside the remainder of the species. Two Australian radiations comprise the bulk of Hypseleotris, one primarily in the northwestern coastal rivers and a second inhabiting the southeastern region including the Murray–Darling, Bulloo-Bancannia and Lake Eyre basins, plus coastal rivers east of the Great Dividing Range. Our phylogenetic results reveal cytonuclear discordance between the UCE and mitochondrial hypotheses, place hemiclone hybrids among their parental taxa, and indicate that the genus Kimberleyeleotris is nested within the northwestern Hypseleotris radiation along with three undescribed species. We infer a crown age for Hypseleotris of 17.3 Ma, date the radiation of Australian species at roughly 10.1 Ma, and recover the crown ages of the northwestern (excluding H. compressa) and southeastern radiations at 5.9 and 7.2 Ma, respectively. Range-dependent diversification analyses using GeoSSE indicate that speciation and extinction rates have been steady between the northwestern and southeastern Australian radiations and between smaller radiations of species in the Kimberley region and the Arnhem Plateau. Analysis of phased SNPs confirms inheritance patterns and reveals high levels of heterozygosity among the hemiclones. CONCLUSIONS: The northwestern species have restricted ranges and likely speciated in allopatry, while the southeastern species are known from much larger areas, consistent with peripatric speciation or allopatric speciation followed by secondary contact. Species in the northwestern Kimberley region differ in shape from those in the southeast, with the Kimberley species notably more elongate and slender than the stocky southeastern species, likely due to the different topographies and flow regimes of the rivers they inhabit

Natural climate solutions

Our thanks for inputs by L. Almond, A. Baccini, A. Bowman, S. CookPatton, J. Evans, K. Holl, R. Lalasz, A. Nassikas, M. Spalding, M. Wolosin, and expert elicitation respondents. Our thanks for datasets developed by the Hansen lab and the NESCent grasslands working group (C. Lehmann, D. Griffith, T. M. Anderson, D. J. Beerling, W. Bond, E. Denton, E. Edwards, E. Forrestel, D. Fox, W. Hoffmann, R. Hyde, T. Kluyver, L. Mucina, B. Passey, S. Pau, J. Ratnam, N. Salamin, B. Santini, K. Simpson, M. Smith, B. Spriggs, C. Still, C. Strömberg, and C. P. Osborne). This study was made possible by funding from the Doris Duke Charitable Foundation. Woodbury was supported in part by USDA-NIFA Project 2011-67003-30205 Data deposition: A global spatial dataset of reforestation opportunities has been deposited on Zenodo (https://zenodo.org/record/883444). This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1710465114/-/DCSupplemental.Peer reviewedPublisher PD

Oligosaccharide and Glycoprotein Microarrays as Tools in HIV Glycobiology Glycan-Dependent gp120/Protein Interactions

AbstractDefining HIV envelope glycoprotein interactions with host factors or binding partners advances our understanding of the infectious process and provides a basis for the design of vaccines and agents that interfere with HIV entry. Here we employ carbohydrate and glycoprotein microarrays to analyze glycan-dependent gp120-protein interactions. In concert with new linking chemistries and synthetic methods, the carbohydrate arrays combine the advantages of microarray technology with the flexibility and precision afforded by organic synthesis. With these microarrays, we individually and competitively determined the binding profiles of five gp120 binding proteins, established the carbohydrate structural requirements for these interactions, and identified a potential strategy for HIV vaccine development