2,485 research outputs found

    Modified DFT-based phasor estimation algorithms for numerical relaying applications

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    This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TPWRD.2017.2738621, IEEE Transactions on Power Delivery

    Selectivity of 130 mm Mesh Size in Deep Sea Bottom Trawl Fishery in NAFO Regulatory Area

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    In February 1995 the European Union carried out a selectivity survey on board a Spanish commercial trawler, using the codend-cover method. The objective was to study the selectivity of 130 mm mesh size for the deep sea trawl fisheries in the NAFO Regulatory Area. One hour and four hour hauls were carried out and results obtained for Greenland halibut (Reinhardtius hippoglossoides), American plaice (Hippoglossoides platessoides), roughhead grenadier (Macrourus berglax) and threebeard rockling (Gaidropsarus ensis). For the two flatfish species, the proportion of retention increased with the duration of the haul. This increase reflected in a decrease of the corresponding selection factor. It also varied with the size of fish. The selection factor was greater in smaller individuals, and this induced an asymmetry in the selectivity curve. For the groundfish species, data were enough only to fit the four hour selectivity curves, which appeared more symmetrical than the flatfish ones

    Selectivity of 130 mm Mesh Size in Deep Sea Bottom Trawl Fishery in NAFO Regulatory Area

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    In February 1995 the European Community carried out .a selectivity campaign on board of a Spanish commercial trawler, using the codend cover method. The objective was to study the selectivity of 130 mm mesh size for the deep sea trawl fisheries in the NAFO Regulatory Area. One hour and four hour hauls were used and results obtained for Greenland halibut, American plaice, roughhead grenadier and theebeard rockling. For the two flatfish species the proportion of retention increase with the duration of the haul. This increase, reflected in a decrease of the corresponding selection factor, also varies with the size of fish, being greater in smaller individuals, and induces an asymmetry in the selectivity curve. For the roundfish species data were enough only to fit the four hour selectivity curves, both appearing more symmetrical than the flatfishes ones

    Modelling the distribution of a commercial NE-Atlantic sea cucumber, Holothuria mammata : demographic and abundance spatio-temporal patterns

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    Funding: This study was financed by the Operational Programme Mar2020, MAR-02.01.01-FEAMP-0052, “Newcumber – Avanços para o cultivo sustentável de pepinos do mar”. It received further financial support from Fundação para a Ciência e Tecnologia (projects UIDB/04292/2020, UIDB/00006/2020, CoastNet – PINFRA/22128/2016, AB with the Scientific Stimulus Programme – CEECIND/00095/2017 and FA with the individual research grant 2020.09563.BD). This publication was financed by Portuguese national funds through FCT – Fundação IP under project reference UIDB/04292/2020, and by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement N810139: Project Portugal Twinning for Innovation and Excellence in Marine Science and Earth Observation – PORTWIMS.There is an increasing demand for sea cucumbers, for human consumption, mainly from Asian markets and, as a consequence, NE-Atlantic species are now new targets for exploitation and exportation. Holothuria mammata is one of the most valuable species in Europe. However, the lack of historical economic interest in this species in most European countries has also led to a lack of studies concerning biological and ecological aspects on wild populations and this is a major issue for stock management. This study aims to determine the temporal and spatial patterns of distribution of H. mammata, considering its abundance and demographic structure in a NE-Atlantic area, SW Portugal, as a function of environmental conditions. For that, a population from a marine protected area was followed for 1 year at 1.5-month intervals. Throughout the coastal area, six sites were selected and at each sampling campaign three random transects per site and substrate (rock and sand) in which all H. mammata individuals were counted and measured. For each site and survey several environmental parameters of interest, from the water column, the sediment and substrate cover, were also measured. Generalized Linear Models were used to model the spatial and temporal distribution of the species according to environmental conditions, to determine the species’ habitat preferences. The distribution models indicate that abiotic and biotic parameters of the water column are not the main drivers shaping the distribution of H. mammata. The species has a patchy distribution, and its habitat preferences depend on environmental stability, the presence of shelter and habitat complexity, which is more important for smaller, more vulnerable, individuals, while bigger size classes tend to venture more into less stable environments in an opportunistic fashion. The knowledge of these population traits is determinant to develop stock management measures, which are now urgent to prevent the depletion of commercial sea cucumber populations in the NE-Atlantic. Sustainable fisheries policies should be developed and start by considering to delimit fishing areas and periods, considering the species spatial and temporal distribution patterns.Publisher PDFPeer reviewe

    First record of the miniature catfish Malacoglanis gelatinosus Myers & Weitzman, 1966 (Siluriformes, Trichomycteridae) in the Orinoco river basin

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    Malacoglanis gelatinosus, a species of miniature catfish of the family Trichomycteridae, is only known from 4 specimens from the Amazon basin. Recently, we collected 3 specimens from the upper basin of the Meta River, a tributary of the Orinoco. This is the first record of M. gelatinosus from the Orinoco river basin, which significantly expands the known geographic distribution of this species, making it one of the most broadly distributed species within the subfamily Sarcoglanidinae. High-resolution photographs of specimens, remarks on character variation, and an updated distribution in Colombia are provided

    Solitary wave trains in granular chains: Experiments, theory and simulations

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    The features of solitary waves observed in horizontal monodisperse chain of barely touching beads not only depend on geometrical and material properties of the beads but also on the initial perturbation provided at the edge of the chain. An impact of a large striker on a monodisperse chain, and similarly a sharp decrease of bead radius in a stepped chain, generates a solitary wave train containing many single solitary waves ordered by decreasing amplitudes. We find, by simple analytical arguments, that the unloading of compression force at the chain edge has a nearly exponential decrease. The characteristic time is mainly a function involving the grains' masses and the striker mass. Numerical calculations and experiments corroborate these findings.Comment: The original publication is available at http://www.springerlink.com (related papers at http://www.supmeca.fr/perso/jobs

    A Confidence Interval for the Wallace Coefficient of Concordance and Its Application to Microbial Typing Methods

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    Very diverse research fields frequently deal with the analysis of multiple clustering results, which should imply an objective detection of overlaps and divergences between the formed groupings. The congruence between these multiple results can be quantified by clustering comparison measures such as the Wallace coefficient (W). Since the measured congruence is dependent on the particular sample taken from the population, there is variability in the estimated values relatively to those of the true population. In the present work we propose the use of a confidence interval (CI) to account for this variability when W is used. The CI analytical formula is derived assuming a Gaussian sampling distribution and recurring to the algebraic relationship between W and the Simpson's index of diversity. This relationship also allows the estimation of the expected Wallace value under the assumption of independence of classifications. We evaluated the CI performance using simulated and published microbial typing data sets. The simulations showed that the CI has the desired 95% coverage when the W is greater than 0.5. This behaviour is robust to changes in cluster number, cluster size distributions and sample size. The analysis of the published data sets demonstrated the usefulness of the new CI by objectively validating some of the previous interpretations, while showing that other conclusions lacked statistical support

    Alternative splicing of a previously unidentified CFTR exon introduces an in-frame stop codon 5' of the R region

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    AbstractThe cystic fibrosis transmembrane conductance regulator (CFTR) has been extensively characterized as the carrier of the basic defect in cystic fibrosis. CFTR is part of a growing family of proteins encoded by a single gene, the variant isoforms of which are generated by alternative splicing or RNA editing. We have analyzed the CFTR mRNA in the region of exons 10–11 in T84 cells and detected an alternatively spliced exon (10b) accounting for about 5% of the CFTR mRNA. The exon lOb found in both the human and mice genomes, introduces an inframe stop codon. The resulting mRNA is translated into a truncated CFTR protein, identified in T84 cells by immunoprecipitation with the CFTR-specific monoclonal antibody MATG 1061. The insertion of a differentially spliced exon carrying an inframe stop codon is a novel cellular mechanism for the production of a protein sharing common sequences with another, but having different properties and functions

    First records of the family Scoloplacidae (Siluriformes, Loricarioidei) in Colombia, including a range expansion of Scoloplax baileyi Rocha, Lazzarotto & Py-Daniel, 2012

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    The Neotropical family Scoloplacidae is a monogeneric group of miniature freshwater catfishes that includes 6 species. Scoloplax dicra has the widest distribution across the Amazon basin, except in the western upper portions. We collected 3 specimens from localities close to Leticia in Colombia, corresponding to S. baileyi and S. dicra, constituting the westernmost records of the family for the Amazon basin and the first for Colombia
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