1,256 research outputs found

    Significant parameters of mining properties in arctic and subarctic areas of North America

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    Editors: Bruce W. Campbell and John J. DiMarchiThis paper is a review of those factors unique to mining in the Arctic and subarctic. The information was developed from an exhaustive Literature search and personal visits to several northern mines in North America. The intent is to present a broad overview of many of these factors, to identify and stimulate consideration of parameters that are likely to be overlooked by companies end persons wlthout p rior arctic experience. Topics of discussion include exploration, cold weather plant design, blasting in permafrost, living conditions and employees relations. The appendices are a brief discussion of a number of the arctic and subarctic operations in North America. In brief, minlng in northern regions is practical provided the deposit has sufficient value to support the higher construction, transportation and operating costs associated with the remoteness and cold weather. Hiring and retaining good employees and integrating the native labor force into the operation have proven to be the most difficult problems. Equipment and plant operation are problems more easily solved.This report is a revised and edited form of the report by the same authors and originally titled "Identification of and Significant Parameters of Mining Properties located in Arctic and Subarctic areas of Norther America", under U.S. Bureau of Mines Contract No. S0144117

    Overtraining and exercise motivation: A research prospectus

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    The problems of exercise overtraining has recently become one of great interest to professionals in the field of human performance assessment. Quite obviously, the ultimate goal of the training process is to improve physical performance. However, excessive training can result in the opposite effect, that is, a performance decline and an impairment in the functional work capacity of the body. Research indicates that both psychological as well as physiological disturbances are quite common in overtrained individuals. For example, psychological changes include increased levels of depression, fatigue, and a lack of motivation. Similarly, impairment of the physiological function of the cardiovascular, metabolic, and endocrine systems also have been found. Some similarities may be found in the psychological and physiological states of crew members exposed to extended space flight and overtrained individuals. Therefore, the possibility exists that the crew members subjected to extended missions in space may develop overstressed or overtrained or both states during their flights. If such states do develop within the crew members, mission performance may be impaired. With these points as a background, the intent is to address potential research directions that NASA may consider viable and of a mutual interest to the researcher. A clear framework by which to begin discussion of research topics is needed; therefore, working definitions of overtraining and exercise motivation are presented. Subsequently, a proposed conceptional model of how exercise overtraining and motivation interact is presented. In support of the proposed model is a brief literature review of relevant areas. Potential research projects are presented and discussed

    A criterion for existence of right-induced model structures

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    Suppose that F:N→MF: \mathcal{N} \to \mathcal{M} is a functor whose target is a Quillen model category. We give a succinct sufficient condition for the existence of the right-induced model category structure on N\mathcal{N} in the case when FF admits both adjoints. We give several examples, including change-of-rings, operad-like structures, and anti-involutive structures on infinity categories. For the last of these, we explore anti-involutive structures for several different models of (∞,1)(\infty, 1)-categories, and show that known Quillen equivalences between base model categories lift to equivalences

    Ultraviolet and X-ray observations of the BL Lac object PKS 05 8-322

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    Spectrophotometric observations of the BL Lac object PKS 0548-322 were made with ultraviolet and X-ray instruments on the IUE and HEAO-2 satellites. Two observations in each spectral region, one set of which was obtained simultaneously are presented. A power law of energy index approximately 1.0 gives a good description of the data from ultraviolet through X-ray frequencies. This source is reported to be variable on short timescales (Gilmore 1980); the implications of the spectral properties and apparent variability are discussed in light of a relativistic jet model. Findings support the jet picture of BL Lac objects

    Clinical management of immunosuppression in sportsmen-women: recommendations for sports medicine physicians and physiotherapists

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    In sportsmen and sportswomen the Overtraining Syndrome (OTS) can be a physically debilitating medical condition that results in these men and women being totally compromised in their capacity to perform and compete athletically. Many physiological systems are affected by the process of overtraining and the OTS; but one system in particular, the immune, is highly susceptible to degradation resulting in a reduction in overall health and performance. The aim of this paper is twofold; 1) to review the evidence-based proactive steps and actions to greatly reduce the risk of development of an infection or a compromised immune system in sportsmen; and 2) to recommend the course of action for clinicians when they are dealing with an sportsmen and women displaying overt signs of an infection and, or inflammation. Based upon the evidence reviewed-presented herewithin, it can be concluded that it is essential for clinicians to take practical preventative and management steps – actions with sportsmen-women involved in intensive exercise training in order to help preserve a healthy and robust immune system

    Characterization of the prolactin response to prolonged endurance exercise

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    This study characterized the blood prolactin responses to a prolonged endurance exercise bout in comparison to a resting, control period with no exercise. Six healthy exercise trained males completed both a 90 minute cycle exercise (70% VO2max) and a rest-control experimental session under standardized conditions. Blood samples were collected at – 15, 0 (exercise start), 15, 30, 45, 60, 75, 90 (exercise end), 105, and 120 minute time points in the exercise and rest-control sessions. Prolactin concentrations were analyzed using radioimmunoassay procedures and tested for significant changes with ANOVA analysis. In the exercise session, prolactin concentrations from 45 to 120 minutes were significantly greater than the 15 minute concentration before exercise (p < 0.01). Furthermore, the exercise concentrations at 45 to 120 minutes were also significantly greater than the concentrations observed at the comparable rest-control time points (p < 0.01; approximately 300% elevation). The frequent blood sampling protocol used in this study clearly portrays the magnitude, timeline, and extend of the prolactin response to prolonged endurance activity. The mechanism and role for the prolactin response was not the focus of this study, but relative to the latter, it is speculated the hormonal change could pertain to signaling energy usage-status within the body and, or prompting immune system activation

    Comparison of the personality traits of male and female BASE jumpers

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    BASE jumping is an extreme adventure sport which consists of jumping from a fixed object with specially adapted parachutes. A few studies of the personality of BASE jumpers have been conducted, but little is known about how the women in this sport compare to the men. The purpose of this study is to compare the personality traits among a sample of men and women who are experienced BASE jumpers, as this provides an interesting and important opportunity to better understand the motivation for extreme sports. Eighty-three participants completed the Temperament and Character Inventory the day before the jump at the New River Gorge Bridge Day BASE Jumping event, West Virginia, United States. The sample included 64 men and 19 women. Results show that men and women BASE jumpers shared similar personality traits both in terms of temperament and character, except for the character trait of cooperativeness on which women scored higher than men. This suggests that the basic drive for participation in extreme sports is self-regulation of personal emotional drives and needs for self-actualization, rather than to oppose social pressure or cultural bias against female participation. These findings are discussed in relation with other studies conducted among extreme athletes and in terms of congruence between personality and activity

    Photochemical colour change for traditional watercolour pigments in low oxygen levels

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    An investigation for light exposure on pigments in low-oxygen environments (in the range 0–5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia. The pigments were prepared for usage in watercolour painting: ground and mixed in gum Arabic and applied to historically accurate gelatine glue-sized cotton and linen-based papers. Anoxia benefited many colorants and no colorant fared worse in anoxia than in air, with the exception of Prussian blue and Prussian green (which contains Prussian blue). A Prussian blue sampled from the studio materials of J.M.W. Turner (1775 − 1851) was microfaded in different environments (normal air (20.9% oxygen) 0, 1, 2, 3.5, or 5% oxygen in nitrogen) and the subsequent dark behaviour was measured. The behaviour of the sample (in normal air, anoxia, and 5% oxygen in nitrogen) proved to be consistent with the 55 separately sourced Prussian blue samples. When exposed to light in 5% oxygen in nitrogen, Prussian blue demonstrated the same light stability as in air (at approximately 21°C and 1 atmosphere). Storage in 5% oxygen is proposed for ‘anoxic’ display of paper-based artworks that might contain Prussian blue, to protect this material while reducing light-induced damage to other components of a watercolour, including organic colorants and the paper support

    The homotopy theory of simplicial props

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    The category of (colored) props is an enhancement of the category of colored operads, and thus of the category of small categories. In this paper, the second in a series on "higher props," we show that the category of all small colored simplicial props admits a cofibrantly generated model category structure. With this model structure, the forgetful functor from props to operads is a right Quillen functor.Comment: Final version, to appear in Israel J. Mat

    Coextension of scalars in operad theory

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    The functor between operadic algebras given by restriction along an operad map generally has a left adjoint. We give a necessary and sufficient condition for the restriction functor to admit a right adjoint. The condition is a factorization axiom which roughly says that operations in the codomain operad can be written essentially uniquely as operations in arity one followed by operations in the domain operad
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