1,863 research outputs found

    Lamb marking

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    LAMB marking is the most severe of the various ordeals which sheep are called upon to endure during their lifetimes—yet it is an operation, or rather a series of operations, to which the average fiockowner gives but little care and thought

    Fleece measurements in selecting merino sheep.

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    During recent months a number of well-attended fleece measurement demonstrations have been held in various districts. The object of the demonstrations was to make studbreeders familiar with the technique under shearing-shed conditions and, during discussion, gain a clearer understanding of fleece measurement and its application to stud-breeding. From a small group of sheep, the stud-breeders selected those they considered carried the heaviest and lightest fleeces. The whole group was then shorn and the fleeces weighed, classed and valued. The demonstrations have shown definitely that selecting for fleece weight by eye and touch is inefficient compared with the scales

    Gravity and magnetic observations in the Red Hill area, Southern Tasmania

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    The results of reconnaissance gravity and magnetic traverses in the Red Hill area of Tasmania confirm the structure postulated as most likely on geological evidence. The granophyre which occurs in the higher parts of the Red Hill Dyke has arisen by differentiation of dolerite in situ, but the gravity work shows that it is unlikely that the dyke continues to a depth sufficient for all the granophyre to have been produced solely by differentiation of the vertical column of dolerite, so that some migration of acid residuum from the underlying dolerite sheet into the dyke has probably taken place. The measurements illustrate how geophysical methods can be helpful in structural problems where dolerite has intruded less dense sediments, but show that caution is necessary when interpreting the results of magnetic surveys

    The V<sub>H</sub> repertoire and clonal diversification of B cells in inflammatory myopathies

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    The contribution of antigen-driven B-cell adaptive immune responses within the inflamed muscle of inflammatory myopathies (IMs) is largely unknown. In this study, we investigated the immunoglobulin VH gene repertoire, somatic hypermutation, clonal diversification, and selection of infiltrating B cells in muscle biopsies from IM patients (dermatomyositis and polymyositis), to determine whether B cells and/or plasma cells contribute to the associated pathologies of these diseases. The data reveal that Ig V&lt;sub&gt;H&lt;/sub&gt; gene repertoires of muscle-infiltrating B cells deviate from the normal VH gene repertoire in individual patients, and differ between different types of IMs. Analysis of somatic mutations revealed clonal diversification of muscle-infiltrating B cells and evidence for a chronic B-cell response within the inflamed muscle. We conclude that muscle-infiltrating B cells undergo selection, somatic hypermutation and clonal diversification in situ during antigen-driven immune responses in patients with IMs, providing insight into the contribution of B cells to the pathological mechanisms of these disorders

    Antibodies to acetylcholine receptor in parous women with myasthenia: evidence for immunization by fetal antigen

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    The weakness in myasthenia gravis (MG) is mediated by autoantibodies against adult muscle acetylcholine receptors (AChR) at the neuromuscular junction; most of these antibodies also bind to fetal AChR, which is present in the thymus. In rare cases, babies of mothers with MG, or even of asymptomatic mothers, develop a severe developmental condition, arthrogryposis multiplex congenita, caused by antibodies that inhibit the ion channel function of the fetal AChR while not affecting the adult AChR. Here we show that these fetal AChR inhibitory antibodies are significantly more common in females sampled after pregnancy than in those who present before pregnancy, suggesting that they may be induced by the fetus. Moreover, we were able to clone high-affinity combinatorial Fab antibodies from thymic cells of two mothers with MG who had babies with arthrogryposis multiplex congenita. These Fabs were highly specific for fetal AChR and did not bind the main immunogenic region that is common to fetal and adult AChR. The Fabs show strong biases to VH3 heavy chains and to a single Vk1 light chain in one mother. Nevertheless, they each show extensive intraclonal diversification from a highly mutated consensus sequence, consistent with antigen-driven selection in successive steps. Collectively, our results suggest that, in some cases of MG, initial immunization against fetal AChR is followed by diversification and expansion of B cells in the thymus; maternal autoimmunity will result if the immune response spreads to the main immunogenic region and other epitopes common to fetal and adult AChR

    Time of lambing experiment : Merredin Research Station, 1959-60 (Progress report)

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    FOLLOWING upon the Time of Lambing Experiments at Esperance Plains Research Station (Journal of Agriculture, May, 1960) it was decided to carry out similar work with Merino sheep under the relatively harsher environment at Merredin Research Station

    Invasiveness of plants is predicted by size and fecundity in the native range

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    This is the final version of the article. Available from Wiley via the DOI in this record.An important goal for invasive species research is to find key traits of species that predispose them to being invasive outside their native range. Comparative studies have revealed phenotypic and demographic traits that correlate with invasiveness among plants. However, all but a few previous studies have been performed in the invaded range, an approach which potentially conflates predictors of invasiveness with changes that happen during the invasion process itself. Here, we focus on wild plants in their native range to compare life-history traits of species known to be invasive elsewhere, with their exported but noninvasive relatives. Specifically, we test four hypotheses: that invasive plant species (1) are larger; (2) are more fecund; (3) exhibit higher fecundity for a given size; and (4) attempt to make seed more frequently, than their noninvasive relatives in the native range. We control for the effects of environment and phylogeny using sympatric congeneric or confamilial pairs in the native range. We find that invasive species are larger than noninvasive relatives. Greater size yields greater fecundity, but we also find that invasives are more fecund per-unit-size. SYNTHESIS: We provide the first multispecies, taxonomically controlled comparison of size, and fecundity of invasive versus noninvasive plants in their native range. We find that invasive species are bigger, and produce more seeds, even when we account for their differences in size. Our findings demonstrate that invasive plant species are likely to be invasive as a result of both greater size and constitutively higher fecundity. This suggests that size and fecundity, relative to related species, could be used to predict which plants should be quarantined.We thank the National Trust and Cornwall Wildlife Trust for access to field sites, Dr. Colin French for use of the ERICA database, and Luke Davis and Cheryl Mills for assistance during data collection. KJ was supported by the University of Exeter as part of its wildlife research partnership with DEFRA's National Wildlife Management Centre. DH was supported by the Natural Environment Research Council grant reference NE/L007770/1
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