Subglacial drainage processes at a High Arctic polythermal valley glacier

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Exploration History and Mineral Potential of the Central Arctic Zn-Pb District, Nunavut

Exploration in the central Arctic Zn-Pb District took place in five phases: 1) an initial exploration period (1960–70), during which most surface showings on Cornwallis and Little Cornwallis islands were found; 2) a discovery period (1971–79), during which the buried Polaris ore body was discovered and its feasibility and viability established, new showings were found farther afield, and many showings received limited drill testing; 3) the production period (1980–88), dominated by drilling at Polaris Mine; 4) an ore-replacement exploration period (1989–2001), during which showings close to Polaris were extensively drilled, showings on Cornwallis Island drill tested, and new showings found and drilled farther away; and 5) a reclamation period (2002–05), during which the infrastructure was removed and the mine site restored. Factors affecting the timing and rate of exploration were generally intrinsic to the region: 1) discovery of showings in 1960, 2) discovery of the Polaris ore body in 1971, 3) declining reserves between 1989 and 2002, 4) closure of the mine in 2002, 5) the short exploration season and difficult logistics, and 6) lack of competition. The external drivers of exploration were 1) oil-related exploration that led to the discovery of the Polaris showings, 2) the onset of regional exploration coinciding with spikes in the price of zinc, and 3) the surge in scientific interest in carbonate-hosted Zn-Pb deposits in 1967. Probabilistic, discovery-time curve analysis indicates that over 50 showings remain undiscovered. Because logistics controlled the target selection, the standard assumption of a logical discovery process (from largest target to smallest target) is likely invalid. This means that large, untested targets may still exist in the district.Les travaux d’exploration dans le district de Zn-Pb du centre de l’Arctique se sont déroulés en cinq étapes : 1) une période d’exploration initiale (1960 - 1970), durant laquelle la plupart des traces détectées sur l’île Cornwallis et la Petite île Cornwallis ont été trouvées; 2) une période de découverte (1971- 1979), pendant laquelle la zone de minéralisation enterrée de Polaris a été découverte et sa faisabilité et sa rentabilité ont été déterminées, de nouvelles traces ont été décelées plus au loin, et de nombreuses traces ont fait l’objet d’un nombre restreint d’essais de foration; 3) une période de production (1980-1988), dominée par les travaux de foration à la mine Polaris; 4) une période d’exploration de remplacement de minerai (1989- 2001), dans le cadre de laquelle les traces situées à proximité de Polaris ont fait l’objet de forations intenses, les traces de l’île Cornwallis ont fait l’objet d’essais et de nouvelles traces ont été découvertes et forées plus loin; et 5) une période de remise en état (2002-2005), durant laquelle l’infrastructure a été retirée et l’emplacement de la mine a été restauré. Généralement, les facteurs touchant la programmation et le régime d’exploration étaient intrinsèques à la région : 1) la découverte des traces en 1960, 2) la découverte du corps minéralisé de Polaris en 1971, 3) la diminution des réserves entre 1989 et 2002, 4) la fermeture de la mine en 2002, 5) la courte saison d’exploration et la logistique qui présentait des difficultés, et 6) l’absence de concurrence. Les motifs externes à l’exploration étaient les suivants : 1) l’exploration pétrolière qui a engendré la découverte des traces de Polaris, 2) le début de l’exploration régionale qui coïncidait avec les variations brusques du prix du zinc, et 3) l’intérêt soudain, dans le monde scientifique, envers les gisements de Zn-Pb dans la roche hôte carbonatée en 1967. L’analyse probabiliste de la courbe de découverte par rapport au temps indique que plus d’une cinquantaine de traces n’ont toujours pas été découvertes. Puisque la logistique décidait du choix des cibles, il est très vraisemblable que l’hypothèse standard d’un processus de découverte logique (de la cible la plus grande à la cible la plus petite) ne soit pas valable. Cela signifie que de vastes cibles n’ayant pas fait l’objet d’essais existent encore dans le district

Six-year record of oxygen and hydrogen isotope variations in South Pole firn

Direct measurements of snow accumulation at stakes near the South Pole over a 6-year period (1958–1963) provide an unusual opportunity to check the reliability of accumulation and annual-layer determinations by stratigraphic and isotopic methods. The results are gratifying. Agreement between interpretations based on stratigraphic and isotopic data is excellent, and both are consistent with accumulation-stake measurements in nearly all respects. All three procedures indicate an average annual accumulation of 7 cm of water at the South Pole over the 1958–1963 interval. Isotope data suggest that depth-hoar formation may result in relative enrichment in O^(18). This could come about through partial recondensation of vapor generated within the depth-hoar layer accompanied by escape of residual vapor impoverished in O^(18)

Stressors, Recovery Processes, and Manifestations of Training Distress in Dance

Abstract Dancers are expected to maintain consistently high levels of performance capability and to perform on demand. To meet these expectations, they subject their bodies to long hours of intensive physical training. Such training regimens are often combined with tight rehearsal and performance schedules, which over time, can lead to persistent fatigue, psychological distress, performance decrements, and injury. A similar process has been observed as a consequence of high-intensity training in many different sports, and considerable sport-related research has been devoted to identifying the antecedents, the symptoms that are experienced, and the most cost-effective ways of monitoring symptom development. This paper presents a general heuristic framework for understanding this “training distress process” and discusses the framework with specific reference to dance

Liver Transplantation for Advanced Liver Disease with Alpha-1antitrypsin Deficiency

ALPHA-1-antitrypsin deficiency associated with chronic obstructive airway disease was recognized in 1963 by Laurell and Ericksson.1 In 1969, Sharp2 described the first cases of alpha-1-antitrypsin-deficiency disease in children with cirrhosis. Since then, this inborn error has been recognized as one of the more common factors in cirrhosis of infancy and childhood,3 including “neonatal hepatitis.”4 Alpha-1-antitrypsin is a glycoprotein that accounts for a major portion of the alpha-1 globulin fraction of the serum.5 It is responsible for approximately 90 per cent of the antitrypsin activity6 of the serum, and it also inhibits several other plasma enzymes, including plasmin,7 elastase,8 collagenase,9 and. © 1980, Massachusetts Medical Society. All rights reserved

Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)

The Torngat Mountains National Park, northern Labrador, Canada, contains more than 120 small glaciers: the only remaining glaciers in continental northeast North America. These small cirque glaciers exist in a unique topo-climatic setting, experiencing temperate maritime summer conditions yet very cold and dry winters, and may provide insights into the deglaciation dynamics of similar small glaciers in temperate mountain settings. Due to their size and remote location, very little information exists regarding the health of these glaciers. Just a single study has been published on the contemporary glaciology of the Torngat Mountains, focusing on net mass balances from 1981 to 1984. This paper addresses the extent to which glaciologically relevant climate variables have changed in northern Labrador in concert with 20th-century Arctic warming, and how these changes have affected Torngat Mountain glaciers. Field surveys and remote-sensing analyses were used to measure regional glacier area loss of 27 % from 1950 to 2005, substantial rates of ice surface thinning (up to 6 m yr⁻¹) and volume losses at Abraham, Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances appear to be controlled by variations in winter precipitation and, increasingly, by strong summer and autumn atmospheric warming since the early 1990s, though further observations are required to fully understand mass balance sensitivities. This study provides the first comprehensive contemporary assessment of Labrador glaciers and will inform both regional impact assessments and syntheses of global glacier mass balance

Development and Validation of Lifestyle-Based Models to Predict Incidence of the Most Common Potentially Preventable Cancers.

BACKGROUND: Most risk models for cancer are either specific to individual cancers or include complex or predominantly non-modifiable risk factors. METHODS: We developed lifestyle-based models for the five cancers for which the most cases are potentially preventable through lifestyle change in the UK (lung, colorectal, bladder, kidney, and esophageal for men and breast, lung, colorectal, endometrial, and kidney for women). We selected lifestyle risk factors from the European Code against Cancer and obtained estimates of relative risks from meta-analyses of observational studies. We used mean values for risk factors from nationally representative samples and mean 10-year estimated absolute risks from routinely available sources. We then assessed the performance of the models in 23,768 participants in the EPIC-Norfolk cohort who had no history of the five selected cancers at baseline. RESULTS: In men, the combined risk model showed good discrimination [AUC, 0.71; 95% confidence interval (CI), 0.69-0.73] and calibration. Discrimination was lower in women (AUC, 0.59; 95% CI, 0.57-0.61), but calibration was good. In both sexes, the individual models for lung cancer had the highest AUCs (0.83; 95% CI, 0.80-0.85 for men and 0.82; 95% CI, 0.76-0.87 for women). The lowest AUCs were for breast cancer in women and kidney cancer in men. CONCLUSIONS: The discrimination and calibration of the models are both reasonable, with the discrimination for individual cancers comparable or better than many other published risk models. IMPACT: These models could be used to demonstrate the potential impact of lifestyle change on risk of cancer to promote behavior change

Effect of creatine supplementation on the airways of youth elite soccer players

Introduction Owing to its well-established ergogenic potential, creatine is a highly popular food supplement in sports. As an oral supplement, creatine is considered safe and ethical. However, no data exist on the safety of creatine on lung function in athletes. The aim of this project was to evaluate the effects of a standard course of creatine on the airways of youth elite athletes. Methods Nineteen elite soccer players, 16-21 yr old, completed a stratified, randomized, double-blind, placebo-controlled, parallel-group trial. The creatine group (n = 9) ingested 0.3 g·kg-1⋅d-1 of creatine monohydrate (CM) for 1 wk (loading phase) and 5 g·d-1 for 7 wk (maintenance phase), and the placebo group (n = 10) received the same dosages of maltodextrin. Airway inflammation (assessed by exhaled nitric oxide, FENO) and airway responsiveness (to dry air hyperpnoea) were measured pre- and postsupplementation. Results Mild, unfavorable changes in FENO were noticed by trend over the supplementation period in the CM group only (P = 0.056 for interaction, η2 = 0.199), with a mean group change of 9 ± 13 ppb in the CM group versus -5 ± 16 ppb in the placebo group (P = 0.056, d = 0.695). Further, the maximum fall in forced expiratory volume in 1 s after dry air hyperpnoea was larger by trend postsupplementation in the CM group compared with the placebo group: 9.7% ± 7.5% vs 4.4% ± 1.4%, respectively (P = 0.070, d = 0.975). These adverse effects were more pronounced when atopic players only (n = 15) were considered. Conclusion On the basis of the observed trends and medium to large effect sizes, we cannot exclude that creatine supplementation has an adverse effect on the airways of elite athletes, particularly in those with allergic sensitization. Further safety profiling of the ergogenic food supplement is warranted

Electronic Health Record-Based Surveillance for Community Transmitted COVID-19 in the Emergency Department

Introduction: SARS-CoV-2, a novel coronavirus, manifests as a respiratory syndrome (COVID-19) and is the cause of an ongoing pandemic. The response to COVID-19 in the United States has been hampered by an overall lack of diagnostic testing capacity. To address uncertainty about ongoing levels of SARS-CoV-2 community transmission early in the pandemic, we aimed to develop a surveillance tool using readily available emergency department (ED) operations data extracted from the electronic health record (EHR). This involved optimizing the identification of acute respiratory infection (ARI)-related encounters and then comparing metrics for these encounters before and after the confirmation of SARS-CoV-2 community transmission.Methods: We performed an observational study using operational EHR data from two Midwest EDs with a combined annual census of over 80,000. Data were collected three weeks before and after the first confirmed case of local SARS-CoV-2 community transmission. To optimize capture of ARI cases, we compared various metrics including chief complaint, discharge diagnoses, and ARI-related orders. Operational metrics for ARI cases, including volume, pathogen identification, and illness severity, were compared between the pre- and post-community transmission timeframes using chi-square tests of independence.Results: Compared to our combined definition of ARI, chief complaint, discharge diagnoses, and isolation orders individually identified less than half of the cases. Respiratory pathogen testing was the top performing individual ARI definition but still only identified 72.2% of cases. From the pre to post periods, we observed significant increases in ED volumes due to ARI and ARI cases without identified pathogen.Conclusion: Certain methods for identifying ARI cases in the ED may be inadequate and multiple criteria should be used to optimize capture. In the absence of widely available SARS-CoV-2 testing, operational metrics for ARI-related encounters, especially the proportion of cases involving negative pathogen testing, are useful indicators for active surveillance of potential COVID-19 related ED visits

An investigation into the mechanisms controlling seasonal speedup events at a High Arctic glacier

Seasonal variations in ice motion have been observed at several polythermal ice masses across the High Arctic, including the Greenland Ice Sheet. However, such variations in ice motion and their possible driving mechanisms are rarely incorporated in models of the response of High Arctic ice masses to predicted climate warming. Here we use a three-dimensional finite difference flow model, constrained by field data, to investigate seasonal variations in the distribution of basal sliding at polythermal John Evans Glacier, Ellesmere Island, Canada. Our results suggest that speedups observed at the surface during the melt season result directly from changes in rates of basal motion. They also suggest that stress gradient coupling is ineffective at transmitting basal motion anomalies to the upper part of the glacier, in contrast to findings from an earlier flow line study at the same glacier. We suggest that stress gradient coupling is limited through the effect of high drag imposed by a partially frozen bed and friction induced by valley walls and significant topographic pinning points. Our findings imply that stress gradient coupling may play a limited role in transmitting supraglacially forced basal motion anomalies through Arctic valley and outlet glaciers with complex topographic settings and highlight the importance of dynamically incorporating basal motion into models predicting the response of the Arctic's land ice to climate change