4,714 research outputs found

    Linking Gun Availability to Youth Gun Violence

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    Foreword

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    Foreword

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    Pigeons home faster through polluted air.

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    Air pollution, especially haze pollution, is creating health issues for both humans and other animals. However, remarkably little is known about how animals behaviourally respond to air pollution. We used multiple linear regression to analyse 415 pigeon races in the North China Plain, an area with considerable air pollution, and found that while the proportion of pigeons successfully homed was not influenced by air pollution, pigeons homed faster when the air was especially polluted. Our results may be explained by an enhanced homing motivation and possibly an enriched olfactory environment that facilitates homing. Our study provides a unique example of animals' response to haze pollution; future studies are needed to identify proposed mechanisms underlying this effect

    Strategies in Underwriting the Costs of Catastrophic Disease

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    In this thesis we address the problem of integrated software pipelining for clustered VLIW architectures. The phases that are integrated and solved as one combined problem are: cluster assignment, instruction selection, scheduling, register allocation and spilling. As a first step we describe two methods for integrated code generation of basic blocks. The first method is optimal and based on integer linear programming. The second method is a heuristic based on genetic algorithms. We then extend the integer linear programming model to modulo scheduling. To the best of our knowledge this is the first time anybody has optimally solved the modulo scheduling problem for clustered architectures with instruction selection and cluster assignment integrated. We also show that optimal spilling is closely related to optimal register allocation when the register files are clustered. In fact, optimal spilling is as simple as adding an additional virtual register file representing the memory and have transfer instructions to and from this register file corresponding to stores and loads. Our algorithm for modulo scheduling iteratively considers schedules with increasing number of schedule slots. A problem with such an iterative method is that if the initiation interval is not equal to the lower bound there is no way to determine whether the found solution is optimal or not. We have proven that for a class of architectures that we call transfer free, we can set an upper bound on the schedule length. I.e., we can prove when a found modulo schedule with initiation interval larger than the lower bound is optimal. Experiments have been conducted to show the usefulness and limitations of our optimal methods. For the basic block case we compare the optimal method to the heuristic based on genetic algorithms. This work has been supported by The Swedish national graduate school in computer science (CUGS) and VetenskapsrĂĄdet (VR)

    International Donors’ Influence on International River Basin Organizations in Southern Africa

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    Today, many of the world’s river and lake basins are threatened by environmental problems such as change in river flow, water pollution, reduced water availability, salt water intrusion, or loss of plant and animal species. International River Basin Organizations (RBOs) governing such rivers are increasingly in need to address such challenges. At the same time many of them receive technical and financial support from international donor organizations. The paper therefore addresses the question of how international financing institutions support adaptation capacities of RBOs. The aim is to identify conditions under which donor support to RBOs can support adaptation to environmental changes and improve the resilience of international water basins. It does so by focusing on two cases in Southern Africa, including the Orange-Senqu Basin and the Orange-Senqu River Commission (ORASECOM) as well as the Cubango-Okavango Basin and the Permanent Okavango River Basin Water Commission (OKACOM). The findings of the paper illustrate an ambivalent role of international donors with regard to river basin adaptation. While they do provide important means for adaptation in form of knowledge, financial and technical resources, they can, at the same time, threaten the long-term sustainability of adaptation activities
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