4,014 research outputs found

    The effects of recreational activities on aquatic avifauna

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    Bibliography: pages 83-86.The Rietvlei wetland system, 10 km north of Cape Town, South Africa, supports 158 species of birds (Winterbottom,1960), and is the principal wetland for breeding waterbird numbers in the south-western Cape Province. It is an important collection, pairing and distribution centre prior to the breeding season. Emerging mudflats during evaporation in late summer are a major gathering point for waders before migratory departure. Increasing human pressure on open spaces is threatening this natural habitat of aquatic birds. For future waterbird conservation it is necessary to ascertain the impact of recreation and human disturbance in this area. Recreational activities on the northern of two dredged lakes in the northwestern corner of Rietvlei are therefore examined to investigate possible causal relationships between recreational activity and the numbers and behaviour of aquatic avifauna. Counts of waterbirds were carried out in the presence of people involved with various forms of recreational activity. These observations were made between February and May 1983. As a null hypothesis it is proposed that recreational activities on this lake and wetland system do not have a significant effect upon water birds in the area. The method used to test this hypothesis is based on statistical analysis by computer, with disturbance measured by means of correlation coefficients between recreational activities and bird numbers. The major findings (Chapter 5) and subsequent recommendations (Chapter 6) for waterbird conservation on the Rietvlei dredged lakes are presented, and proposals for further research in this field are suggested

    Butyn Versus Cocaine.

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    Design of the CMS-CASTOR subdetector readout system by reusing existing designs

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    CASTOR is a cylindrical calorimeter with a length of 1.5m and a diameter of 60cm located at 14.3 meters from the CMS interaction point and covering the range in pseudorapidity corresponding to 5.1 < | eta | < 6.6. The CASTOR project was approved in the middle of 2007. Given the limited resources and time, developing a readout system from scratch was excluded. Here the final implementations of the readout chain, the considerations for the different choices as well as the performance of the installed equipment are discussed

    The Vision of Myopes.

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    Optimizing egalitarian performance in the side-effects model of colocation for data center resource management

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    In data centers, up to dozens of tasks are colocated on a single physical machine. Machines are used more efficiently, but tasks' performance deteriorates, as colocated tasks compete for shared resources. As tasks are heterogeneous, the resulting performance dependencies are complex. In our previous work [18] we proposed a new combinatorial optimization model that uses two parameters of a task - its size and its type - to characterize how a task influences the performance of other tasks allocated to the same machine. In this paper, we study the egalitarian optimization goal: maximizing the worst-off performance. This problem generalizes the classic makespan minimization on multiple processors (P||Cmax). We prove that polynomially-solvable variants of multiprocessor scheduling are NP-hard and hard to approximate when the number of types is not constant. For a constant number of types, we propose a PTAS, a fast approximation algorithm, and a series of heuristics. We simulate the algorithms on instances derived from a trace of one of Google clusters. Algorithms aware of jobs' types lead to better performance compared with algorithms solving P||Cmax. The notion of type enables us to model degeneration of performance caused by using standard combinatorial optimization methods. Types add a layer of additional complexity. However, our results - approximation algorithms and good average-case performance - show that types can be handled efficiently.Comment: Author's version of a paper published in Euro-Par 2017 Proceedings, extends the published paper with addtional results and proof

    Re-organisation and industrial relations in the National Health Service in Scotland

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    The SoLid anti-neutrino detector's readout system

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    The SoLid collaboration have developed an intelligent readout system to reduce their 3200 silicon photomultiplier detector's data rate by a factor of 10000 whilst maintaining high efficiency for storing data from anti-neutrino interactions. The system employs an FPGA-level waveform characterisation to trigger on neutron signals. Following a trigger, data from a space time region of interest around the neutron will be read out using the IPbus protocol. In these proceedings the design of the readout system is explained and results showing the performance of a prototype version of the system are presented
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