1,431 research outputs found

    Genetic parameters of wool colour and skin traits in Corriedale sheep.

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    Clean wool colour (CWC) is an important wool price determinant and has been related to suint characteristics, i.e. sudoriparous and sebaceous gland secretions, such as suint percentage and suint K content. In this work heritability, phenotypic and genetic correlations among wool colour and skin traits were examined. The genetic estimates were assessed by Restricted Maximum Likelihood (REML) procedures using average information algorithm (AIREML) in a Corriedale flock. The traits analysed were wool colour traits (CWC), yellow predictive colour (YPC), and Visual Score; suint traits such as suint percentage and potassium and sodium concentrations in suint, and physiological traits such as potassium and sodium concentrations in the skin, including plasma and red blood cells. The objectives of this study were to assess phenotypic and genetic correlations between wool colour and skin traits, and to find the suitability of these traits as indirect selection criteria for clean wool colour. Suint traits were highly genetically correlated to YPC. Suint K, but not suint percentage, was found to have a high genetic correlation with CWC. Skin K, Visual Score, YPC and suint K were amongst the best indirect selection criteria for clean wool colour. However, selection using these traits was expected to reduceCWCfrom 52% to 49% of that estimated under direct selection

    Melhoramento de espécies aquícolas com foco na resistência a doenças.

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    Introdução. Aspectos a serem considerados no melhoramento genético com foco em doenças. Estimativas de herdabilidade e de correlações genéticas entre resistência a doenças e outras características. Cuidados no desenho experimental dos desafios para a fenotipagem de animais. Considerações finais. Referências.bitstream/item/136151/1/CNPASA2015doc17.pd

    Indirect selection criteria against clean wool colour in Corriedale sheep and their effects on wool production traits.

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    The potential of greasy wool colour subjective assessment Visual Colour Score (VCS) and the yellow predictive test (YPC) as indirect selection criteria for reduction of clean wool colour (CWC) in Corriedale sheep was examined. The heritability of these wool colour traits and the wool production traits, greasy (GFW) and clean fleece weights (CFW), and mean fibre diameter (MFD) and the phenotypic and genetic correlations among these traits were estimated from a Corriedale flock using AIREML procedures. A high genetic correlation between YPC and CWC was observed, indicating that YPC could be a suitable indirect selection criterium for CWC. However, direct selection against CWC was predicted to produce faster genetic improvements in CWC than that expected under indirect selection via YPC. Single trait selection based on VCS or YPC were expected to reduce the response in CWC to 51% and 49% of that estimated for direct selection. The positive genetic correlations of CWC, YPC and VCS with CFW and MFD would cause a reduction in both MFD and CFW to result from selection that reduces wool colour. The results showed that the most effective way to genetically improve CWC was through indirect selection to reduce MFD, CFW or GFW, followed by direct selection, but the premiums for CWC in the Corriedale breed may not be sufficient to justify the expected losses in CFW

    A putative resistant DNA marker for wool yellowing susceptibility in sheep.

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    An Australian Merino flock was screened for low (resistant) and high (susceptible) yellow predictive colour (YPC) breeding values in order to compare extreme individuals using the differential display of mRNA technique. One differentially expressed cDNA band was visualised only in the resistant group. This band showed no identity with the DNA sequences of public databases; however, they showed short homologies with three database sequences related to transmembrane signalling functions. The use of these candidate genes as DNA markers needs to be confirmed against sheep with a wide range of susceptibility to wool yellowing to verify the results

    How to Complete an Interactive Configuration Process?

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    When configuring customizable software, it is useful to provide interactive tool-support that ensures that the configuration does not breach given constraints. But, when is a configuration complete and how can the tool help the user to complete it? We formalize this problem and relate it to concepts from non-monotonic reasoning well researched in Artificial Intelligence. The results are interesting for both practitioners and theoreticians. Practitioners will find a technique facilitating an interactive configuration process and experiments supporting feasibility of the approach. Theoreticians will find links between well-known formal concepts and a concrete practical application.Comment: to appear in SOFSEM 201

    Physical Wigner functions

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    In spite of their potential usefulness, the characterizations of Wigner functions for Bose and Fermi statistics given by O'Connell and Wigner himself almost thirty years ago has drawn little attention. With an eye towards applications in quantum chemistry, we revisit and reformulate them in a more convenient way.Comment: Latex, 10 page

    Dominance of unicellular cyanobacteria in the diazotrophic community in the Atlantic Ocean

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    ABSTRACT: The horizontal and vertical distribution of representatives of diazotrophic unicellular cyanobacteria was investigated in the subtropical northeast Atlantic Ocean (28.87 to 42.00°N; 9.01 to 20.02°W). Samples from stations encompassing different water conditions (from oceanic oligotrophic waters to upwelling areas and a temperature range of 13.1°C to 24.2°C) were size fractionated and analyzed for nifH by a nested polymerase chain reaction (PCR) and by tyramide signal amplification–fluorescence in situ hybridization (TSA-FISH) using probe Nitro821. In samples from the surface, mixed-layer depth, and deep chlorophyll maximum waters, most (> 50%) of the nifH recovered was from the 0.2–3 µm fraction and was consistent with TSA-FISH counts. The < 3 µm Nitro821-positive cells were more abundant than the larger cells, and the proportion of single cells was larger than that associated with particulate matter or with larger cells. Phylogenetic analysis of representative samples revealed that most of the sequences belong to diazotrophic unicellular cyanobacteria Group A (UCYN-A or Candidatus Atelocyanobacterium thalassa). N2 fixation in the 0.2–3 µm fraction, putatively representing the activity of UCYN-A, contributed more than 50% of the total N2 fixation. There was a positive relationship of this putative UCYN-A abundance and activity with temperature, and a negative relationship with dissolved O2. The dominance of these putative UCYN-A organisms in nitrate-rich upwelling filament regions suggests that the activity of this group of organisms may not be strongly controlled by the availability of fixed N

    Mesopelagic N-2 fixation related to organic matter composition in the Solomon and Bismarck Seas (Southwest Pacific)

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    Dinitrogen (N-2) fixation was investigated together with organic matter composition in the mesopelagic zone of the Bismarck (Transect 1) and Solomon (Transect 2) Seas (Southwest Pacific). Transparent exopolymer particles (TEP) and the presence of compounds sharing molecular formulae with saturated fatty acids and sugars, as well as dissolved organic matter (DOM) compounds containing nitrogen (N) and phosphorus (P) were higher on Transect 1 than on Transect 2, while oxygen concentrations showed an opposite pattern. N-2 fixation rates (up to similar to 1 nmol N L-1 d(-1)) were higher in Transect 1 than in Transect 2, and correlated positively with TEP, suggesting a dependence of diazotroph activity on organic matter. The scores of the multivariate ordination of DOM molecular formulae and their relative abundance correlated negatively with bacterial abundances and positively with N-2 fixation rates, suggesting an active bacterial exploitation of DOM and its use to sustain diazotrophic activity. Sequences of the nifH gene clustered with Alpha-, Beta-, Gamma- and Deltaproteobacteria, and included representatives from Clusters I, III and IV. A third of the clone library included sequences close to the potentially anaerobic Cluster III, suggesting that N-2 fixation was partially supported by presumably particle-attached diazotrophs. Quantitative polymerase chain reaction (qPCR) primer-probe sets were designed for three phylotypes and showed low abundances, with a phylotype within Cluster III at up to 10(3) nifH gene copies L-1. These results provide new insights into the ecology of non-cyanobacterial diazotrophs and suggest that organic matter sustains their activity in the mesopelagic ocean

    É possível estimar a eficiência real dos anti-helmínticos por meio de testes in vitro?

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    Vantagens e desvantagens dos testes de campo e laboratoriais serão, portanto, abordados neste Comunicado Técnico, que tem por objetivo mostrar a técnicos e ovinocultores (a) os fundamentos dos atuais testes de campo para a avaliação dos isolados de parasitos de animais de campo como resistentes (ou não) a princípios ativos, e (b) os avanços obtidos com os testes laboratoriais de antiparasitários na esperança de facilitar a identificação do antihelmíntico mais recomendado, sem a necessidade de testes a campo.bitstream/item/169049/1/CoT-97-online.pd
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