644 research outputs found

    Fisheries and Aquaculture and Their Potential Roles in Development: An Assessment of the Current Evidence

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    Commissioned by the International Sustainability Unity, this report investigates a number of innovative solutions that have been developed to deal with five key challenges that are impeding progress in achieving sustainable fisheries: overcapacity; perverse subsidies; poor governance; lack of data; and by-catch and discards. These key challenges are interlinked and affect the sustainability of fisheries both directly as well as indirectly by undermining instances of good management. Through 22 case studies demonstrating good practice, we explore how these challenges have been addressed around the world and how these approaches might be scaled up and applied in other fisheries. Each case study draws on published material and interviews with key people involved in the fishery. The main report draws lessons from these case studies

    The diesel-electric locomotive and the railway employees

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    Thesis (Ph.D.) Massachusetts Institute of Technology, Dept. of Economics and Engineering, 1953.Bibliography: leaves [176-180].by Robert James Agnew.Ph.D

    Multiphase gas mechanisms in groundwater

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    Numerous groundwater springs bubble, yet the flow and transport of gases are not well understood in hydrogeology. An understanding of the processes by which gases enter, migrate, and are liberated from groundwater is required. A quantitative conceptual model of gas migration in groundwater will allow an understanding of what informative aquifer signals may be present in gas data, as well as what information signals may be masked or diminished by phase changes. Through analysis of existing published literature, seven facies of groundwater bubbles were developed to provide a framework for research in these specific categories of gas transport. In order to better understand these multiphase bubbling springs, an instrument was designed and deployed over the discharge of a spring in southern Oklahoma that measured the total gas flux, ebullative and diffusive. By measuring the water discharge from the spring too, a hydropneumograph of gas and water mass flux over time can be produced. In addition to the mass flow rates of the two phases provided by the hydropneumograph, water and gas samples were collected for compositional analysis. By combining the compositional data of exsolved and dissolved gas with the mass flow rates from the hydropneumograph, estimation of the quantity of light noble gases is radically changed (60% for He, 45% for Ne) which provides improvements in the calculation of recharge temperature of 4 to 25% depending on the model selected. These improvements in the understanding of the physical hydrogeology of bubbling springs provide an additional avenue for researchers to explore aquifer dynamics that is largely ignored in the extant literature

    The moderating effects of religiosity on the relationship between stressful life events and delinquent behavior

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    Previous research has shown that many forms of strain are positively related to delinquency. Evidence also suggests that religiosity buffers the effects of strain on offending, but this issue requires further research. Using data from a national sample of adolescents, this study examined whether or not religiosity conditioned the relationship between strain and delinquency. This study also looked at the ability of social support, self-esteem, and depression to moderate the influence of strain on delinquent behavior. The findings here lend support to general strain theory in that strain had a direct positive effect on delinquency, yet there was little evidence that the relationship was moderated by religiosity or other conditioning variables. The roles of moderating variables on strain across genders were also considered. Originally published in Journal of Criminal Justice Vol. 36, No. 6 2008

    Entangled Bessel beams

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    Orbital angular momentum (OAM) entanglement is investigated in the Bessel-Gauss (BG) basis. Having a readily adjustable radial scale, BG modes provide a more favourable basis for OAM entanglement over Laguerre-Gaussian (LG) modes. The OAM bandwidth in terms of BG modes can be increased by selection of particular radial modes and leads to a flattening of the spectrum. The flattening of the spectrum allows for higher entanglement. We demonstrate increased entanglement in terms of BG modes by performing a Bell-type experiment and violating the appropriate Clauser Horne Shimony Holt (CHSH) inequality. In addition, we reconstruct the quantum state of BG modes entangled in high-dimensions.Comment: 8 pages, 4 figure

    Using online assessment to replace invigilated assessment in times of a natural disaster: Are some online assessment conditions better than others?

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    As a result of the Canterbury earthquake on 4 September 2010, and associated aftershocks on 22 February 2011 and 13 June 2011, final examinations in the two first-year Economics papers at Canterbury University were cancelled at short notice in Semester 1, 2011. The final examination weightings were spread over the remaining assessments to obtain a final grade for students. This paper attempts to establish how different online assessment conditions affected final grade distributions when online assessments were substituted for an invigilated final examination. Pearson correlation coefficients and Spearman rank-order correlation coefficients were used to show that there was a greater correlation between online quizzes and invigilated assessments when those quizzes were only available for a restricted period of time compared with the whole semester. We found that online quizzes were more closely correlated with invigilated assessments when the first attempt at a quiz was recorded, as opposed to the higher of two attempts. We also found that using the first attempt leads to less grade disruption when compared with a ‘normal’ semester that includes a final examination. Finally, the actual effect on student grades when online quizzes are substituted for a final examination is discussed
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