23,081 research outputs found

    Some observations on washout of brown trout (Salmo trutta L.) eggs in Teesdale streams

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    Brown trout (Salmo trutta) in Teesdale lay their eggs in the streambed gravels in the Autumn, here the eggs slowly develop to emerge as young fry in the Spring. Whilst the eggs are in the gravel they are vulnerable to displacement by high water velocities. Eggs removed in this way are not thought to remain viable since they are very susceptible to death through physical shock - especially in the earlier stages of development. Streams in Teesdale are known to be amongst the most flashy in England and thus are good sites in which to study egg washout. Three field sites were used for the study of egg washout in Teesdale - Great Eggleshope, Thorsgill and Carl becks. This report describes preliminary studies of a varied nature into this subject from which an attempt is made to assess the importance of egg washout to the survival of brown trout in Teesdale

    Effective Improvement of Symptoms in Patients with Acute Migraine by GR43175 Administered in Dispersible Tablets

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    GR43175, a selective 5-HT1-like agonist, was administered as oral dispersible tablets in an open, uncontrolled dose-ranging study to assess its efficacy as an agent for acute migraine. Nine patients, all with well established attacks, were assessed for changes in severity of headache and associated symptoms over 2 h. Drug absorption was compared during and between attacks in five patients. Doses of 140 mg and 280 mg resulted in complete relief of all symptoms within 2 h. Treatment was well tolerated in all patients

    Modeling and Control for Smart Grid Integration of Solar/Wind Energy Conversion System

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    Performance optimization, system reliability and operational efficiency are key characteristics of smart grid systems. In this paper a novel model of smart grid-connected PV/WT hybrid system is developed. It comprises photovoltaic array, wind turbine, asynchronous (induction) generator, controller and converters. The model is implemented using MATLAB/SIMULINK software package. Perturb and observe (P&O) algorithm is used for maximizing the generated power based on maximum power point tracker (MPPT) implementation. The dynamic behavior of the proposed model is examined under different operating conditions. Solar irradiance, temperature and wind speed data is gathered from a grid connected, 28.8kW solar power system located in central Manchester. Real-time measured parameters are used as inputs for the developed system. The proposed model and its control strategy offer a proper tool for smart grid performance optimization

    Supervised Associative Learning in Spiking Neural Network

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    In this paper, we propose a simple supervised associative learning approach for spiking neural networks. In an excitatory-inhibitory network paradigm with Izhikevich spiking neurons, synaptic plasticity is implemented on excitatory to excitatory synapses dependent on both spike emission rates and spike timings. As results of learning, the network is able to associate not just familiar stimuli but also novel stimuli observed through synchronised activity within the same subpopulation and between two associated subpopulations

    Future proofing

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    Drastic improvements in growing technology in the Netherlands have achieved a large reduction in energy use and a striking increase in production

    Proper Motions in the Andromeda Subgroup

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    This article presents results of VLBI observations of regions of H2O maser activity in the Local Group galaxies M33 and IC10. Since all position measurements were made relative to extragalactic background sources, the proper motions of the two galaxies could be measured. For M33, this provides this galaxy's three dimensional velocity, showing that this galaxy is moving with a velocity of 190 +/- 59 km\s relative to the Milky Way. For IC10, we obtain a motion of 215 +/- 42 km/s relative to the Milky Way. These measurements promise a new handle on dynamical models for the Local Group and the mass and dark matter halo of Andromeda and the Milky Way.Comment: 4 pages 1 figures, to appear in the proceedings of "Galaxies in the Local Volume", Astrophysics and Space Science, editors B. Koribalski and H. Jerjen also available at http://www.mpifr-bonn.mpg.de/staff/abrunthaler/pub.shtm
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