459 research outputs found

    Catch-per-unit-effort and Biological Data of Nephrops norvegicus from the SW Ireland Spanish Trawl Fishery

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    Norway lobster Nephrops norvegicus is a burrowing species inhabiting soft bottoms in the NE Atlantic and Mediterranean. In European western waters (SW Ireland) Nephrops is a comercial species of the bottom mixed fishery prosecuted by fletes from Ireland, France, UK and Spain. A comprehensive collection (1980-2000) of Spanish trawl fishery data and sampling of landings is available. Although Nephrops is a by-catch spcies for the Spanish trawl fleet, some vessels target it mainly during the spring and summer seasoon. This study presents a summarized description of that fishery and catch per unit effort trends. Annual Nephrops length composition by sex, length-weight relationship, sex-ratio and proportion of ovigerous females are given for the referenced period.IEO FPI grant (BOE 06.10.2000, No9). DEMICES project

    Quasi elastic cross sections for the Bi-209(e, e \u27 p)Pb-208 reaction: Jefferson Lab experiment E06007

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    Quasi elastic cross sections were measured for the first time for both negative and positive missing momenta for the Bi-209(e, e\u27p)Pb-208 reaction leading to the ground state and hole states of Pb-208. Experimental cross sections obtained between -0.3 GeV/c to 0.3 GeV/c agree with theoretical calculations using RDWIA techniques both in shape and magnitude for the ground state. The data for the ground state production of Pb-208 are consistent with a theoretical model assuming a single proton(1.06 +/- 0.10) in the 1h9/2 orbit in Bi-209

    Overview of Neutrino–Nucleus Interactions

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    Neutrino–nucleus reactions are surveyed. The approximations usually made are identified and a comparison to the corresponding electron–nucleus processes is presented. Impulse Approximation (IA), factorization of the cross-section and scaling approaches (SA) to lepton–nucleus scattering are examined in detail

    Overview of neutrino-nucleus quasielastic scattering

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    A review of quasielastic neutrino-nucleus scattering will be presented, with emphasis on bringing together the knowledge (and language) of neutrino physics, electron scattering, and nuclear structure communities. Assumptions commonly made which simplify the theoretical calculations will be examined. Finally, an attempt will be made to identify places where improvement from either theoretical or experimental sides would be more significant.Dirección General de Investigación (DGI). España FPA2007-62216, FIS2008-04189 y FPA2006-13807-C02-01Spanish Consolider-Ingenio programme CPAN CSD2007-0004

    Ionospheric biases correction for coordinates derived from GPS single point positioning

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    Most GPS users employ low cost receivers. These receivers do not allow users to record the pseudorange that they observe, but the computed coordinates. This work presents an original and simple method to correct ionospheric biases introduced in GPS signals. The originality of this method is based on the fact that no pseudorange is needed to correct the biases, only the calculated coordinates are used. This distinguishes this method from other classic alternatives. This paper evaluates the efficiency of the method with the use of real data

    Exploring long-term variability of Nephrops norvegicus population in the Porcupine Bank (SW Ireland)

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    PresentationNephrops norvegicus is a commercial species of the bottom fisheries in European western waters which yield has long-term variability. Their distribution is linked to suitable habitats of muddy sediment in which adults construct burrows but the influence of environmental factors on the populations was poorly investigated. Variability in the catch per unit effort (CPUE) of Nephrops norvegicus from Porcupine Bank (Southwest of Ireland) was explored using a time series approach. The CPUE time series (1979-2005) exhibited a seasonal pattern. The seasonal decomposition of the CPUE shows a declining trend in the trend and cycle component from 1982 onwards. ARMA univariate and dynamic regression models were fitted to the CPUE time series. Population (proportion of males, proportion of ovigerous females and recruits) and North Atlantic Oscillation index were tested at different lags to investigate possible factors related to the yield fluctuations

    MAPPING OF CODA ATTENUATION AT THE EXTEND OF THE NATIONAL SEISMOLOGICAL NETWORK OF GREECE

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    Coda decay rates of 538 vertical components corresponding to local earthquakes which occurred in Greece during the period 1998 to 1999 were used to deduce the coda quality factor (Qc) characteristics in the Hellenic area. The seismograms have been selected from a broader sample of 776 records obtained at 8 stations of the National Seismographic Network operated by the Institute of Geodynamics of the National Observatory of Athens. Earthquake magnitudes range from 2.5 to 4.0; epicentral distances and depths are smaller than 100 km and 40 km, respectively. Using the Single Back Scattering model, the dependence of Qc on frequencies between 1 and 10 Hz has been investigated at each station and the usual Qc =Qo f relationships have been deduced. The spatial distribution of Qo has been drawn using waves that sample approximately equivalent ellipsoidal volumes with semiminor axis up to 100 km. The corresponding map shows a decreasing trend in SN direction
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