701 research outputs found

    The Resonance in the B-P-a Reaction

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    The yield of alpha particles of range greater than 2 cms. from boron bombarded by protons has been studied as a function of bombarding energy in the range from 100 to 200 ekv, using a thin target, either methyl borate or boron trifluoride at pressures of 1 mm. of Hg. The yield vs. energy curve shows an approximately exponential rise on which is superposed a sharp (half breadth ~ 6 ekv) intense line at 150 ± ekv. There is some indication of a weaker and much broader line at 190 ekv. Number range curves are not yet available, but the appearance of pulses on the oscillograph screen leads us to suppose that the high yield (line) at 150 ekv is due to emission of a homogeneous long-range group

    Sports mega-events – three sites of contemporary political contestation

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    This article discusses the contemporary politics of sports mega-events, involving the Olympic Games and Fédération Internationale de Football Association (FIFA) Men’s Football World Cup Finals as well as other lower ‘order’ sports megas, taking two main forms: the promotional and the protest. There is a politics in, and a politics of, sports mega-events. The former focuses on the internal politics of the organizing bodies, such as the International Olympic Committee and FIFA. This form of politics has been written about elsewhere, and hence, there is no detailed discussion in this article about it. Instead this article offers a brief discussion of the range and number of sports mega-events since 2000, an assessment of the contemporary politics of sports mega-events, a focus on three main sites of political contestation – rights, legacy and labour, and finally, it offers conclusions about research into the politics of sports mega-events

    An experimental study of the impulse response of a vibro-impacting cantilever beam

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    The dynamics of a vibro-impacting cantilever beam experiment using an impact load cell is considered. The signal recorded from the cell produces spike train -type data. The issues related to the analysis of such data are discussed; particularly the sampling rate and threshold values. For vibro-impact motion of the beam, the duration of impacts is investigated by using a time of contact measure. The implications are discussed for vibro-impact systems mathematically modelled by using instantaneous impact assumptions (coefficient of restitution). Using the load cell to measure impact forces for the beam system is also considered. Then a delay reconstruction of the dynamics of the system by using interspike intervals is considered. It is demonstrated how this process is effected by the influence of noise and the data-acquision process using numerical simulations of the experimental data. It is shown how simple periodic motions can be identified by using a probability density approach and possible future research is highlighted

    An Economic Feasibility Study of Irrigated Crop Production in the Pecos Valley of Texas

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    Public concern over the potential effects of energy price increases on the U.S. food and fiber system has been dramatically justified in the Trans Pecos region of Texas where a 450 percent increase in the price of natural gas was followed by the idling of thousands of irrigated acres and the departure of many of the farmers. This study was conducted to provide the answers to two questions: (l) Can an irrigated farm survive in the Trans Pecos? and (2) If it survives, how profitable will it be? Coyanosa, one of the irrigated areas of the Trans Pecos, was selected as a study area, and the St. Lawrence area of the Edwards Plateau was selected to provide comparative estimates of survival and profitability. A modified MOTAD linear programming-simulation model was developed to generate estimates of survival and profitability by recursive simulation of multiple time periods, as follows: (l) development of a farm plan, (2) generation of stochastic prices and yields, (3) simulation and evaluation of the farm plan in operation, and (4) update of the planning situation to reflect adjustments in expected prices, expected yields, and credit restrictions. The model then returns to step l for simulation of the next time period. The model was applied to the Coyanosa and St. Lawrence regions under alternative future scenarios for inflation rates, energy prices, crop prices, and interest rates. The Coyanosa model was also applied under most likely scenario conditions to analyze the effects of alternative levels of risk-aversion and alternative tenure situations. Each application included 20 simulations of a 1O year planning horizon to develop a distribution of outcome. The Coyanosa farm survived about 8 years under the optimistic scenario and 5 years under all other scenarios. The most likely rate of survival was 20-30 percent with a range of 1O percent to 65 percent for other scenarios. The average life and rate of survival was higher for the St. Lawrence farm under all scenarios. The internal rate of return on equity capital for the Coyanosa farm was 36.8 percent under the optimistic scenario and negative under all other scenarios. The rate of return for St. Lawrence was not significantly different for the optimistic scenario; however, it was higher than Coyanosa for all other scenarios. The level of risk-aversion described by the baseline model appears to be relatively high compared to other studies, but there are indications that it may be relatively low for the St. Lawrence area. Both rate of return and survival increased in response to decreased levels of risk-aversion, however, the latter result may be related to the specification of the risk restraint. Land purchase provided higher estimates of survival and profitability than rental or combined rental and purchase. These results seem to relate to the finding that traditional crop share rental arrangements are unsatisfactory for the Coyanosa area. It was concluded from this study that (l) survival and profitability of irrigated crop production in the Coyanosa area will depend greatly upon future levels of inflation, energy prices, crop prices, and interest rates, (2) survival and profitability for Coyanosa will most likely be lower than St. Lawrence, and (3) land purchase provides greater potential survival and profitability than traditional crop share rental arrangements. These conclusions were limited by need for additional research regarding the effects of beginning equity levels and consideration of risk in farm planning. Conclusions were also limited by the data and assumptions utilized in the study

    Mobile, wearable and ingestible health technologies : towards a critical research agenda

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    In this article, we review critical research on mobile and wearable health technologies focused on the promotion of ‘healthy lifestyles’. We begin by discussing key governmental and policy interests which indicate a shift towards greater digital integration in health care. Subsequently, we review relevant research literature, which highlights concerns about inclusion, social justice, and ownership of mobile health data, which we argue, provoke a series of key sociological questions that are in need of additional investigation. We examine the expansion of what counts as health data, as a basis for advocating the need for greater research into this area. Finally, we consider how digital devices raise questions about the reconfiguration of relationships, behaviours, and concepts of individuality

    Understanding Video Game Developers as an Occupational Community

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    The video game industry has rapidly expanded over the last four decades; yet there is limited research about the workers who make video games. In examining these workers, this article responds to calls for renewed attention to the role of the occupation in understanding project-based workers in boundaryless careers. Specifically, this article uses secondary analysis of online sources to demonstrate that video game developers can be understood as a unique social group called an occupational community (OC). Once this classification has been made, the concept of OC can be used in future research to understand video game workers in terms of identity formation, competency development, career advancement and support, collective action, as well as adherence to and deviance from organizational and industry norms

    Normothermic Ex Vivo Lung Perfusion (Novel) as an Assessment of Extended Criteria Donor Lungs: A Prospective Multi-Center Clinical Trial

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    Purpose: Ex vivo lung perfusion (EVLP) allows re-evaluation of extended criteria/marginal donor lungs. This can increase the number of lung transplants. However, the long-term outcomes of transplanting EVLP-screened lungs in a multicenter setting are unknown. We proposed to evaluate the short- and long-term outcomes of EVLP performed at multiple centers. Methods: This is a prospective, nonrandomized clinical trial. Seventeen lung transplant centers in the United States. Adult patients with end-stage pulmonary disease requiring lung transplant from May 2011 to December 2017 were eligible. Lung allografts initially deemed extended criteria/marginal (n=216) were placed on EVLP and re-evaluated prior to transplant. Patients received either standard donors (n=116) or lungs screened with EVLP (n=110). Results: Half of the lung grafts (110/216, 50.9%) placed on EVLP were transplanted. The incidence of primary graft dysfunction 24 hours post-transplant was higher in the EVLP group (25.5% vs 10.3%, p=0.003), but was not significantly different 48 hours (EVLP: 15.5%, control: 9.5%, p=0.49) and 72 hours (13.6% vs 6.9%, p=0.34) post-transplant. Survival was not significantly different between the 2 groups 1 year (n=226, EVLP: 86%, control: 94%, p=0.06), 3 years (n=226, EVLP: 68%, control: 76%, p=0.16, Figure), or 5 years (n=159, EVLP: 59%, control: 65%, p=0.68) post-transplant. There were also no differences in pulmonary function, the incidence of chronic lung allograft dysfunction or quality of life measures post-transplant. Conclusion: In this multicenter study, recipients of lungs that were re-evaluated on EVLP and deemed suitable for transplant had similar outcomes as a recipients of a standard lung transplants. EVLP offers the opportunity to screen donated lungs initially considered high risk and can safely increase the availability of transplantable lungs without compromising outcomes
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