218 research outputs found

    Some rare cases of chimerism in twin cattle and their proposed use in determining germinal cell migration

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    Three dizygotic, heterosexual twins with chimerisms carrying marker chromosomes are described. Phenotypic and cytogenetic methods were used to identify these animals. The occurrence of germinal cell migration causing gonad chimerism can be detected by the marker chromosome event under conditions described in this repor

    Equilibrium in the Assignment Market under Budget Constraints

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    We reexamine the well-known assignment market model in a more general and more practical environment where agents may be financially constrained. These constraints will be shown to have an important impact on the set of Walrasian equilibria. We prove that a price adjustment process will either find a unique minimal Walrasian equilibrium price vector, or exclusively validate the nonexistence of equilibriu

    Canine-Derived Cosmid Probes Containing Microsatellites Can Be Used in Physical Mapping of Arctic Fox (Alopex lagopus) and Chinese Raccoon Dog (Nyctereutes procyonoides procyonoides) Genomes

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    Rapid development of the canine marker genome map facilitates genome mapping of other Canidae species. In this study we present chromosomal localization of 18 canine-derived cosmid probes containing microsatellites in the arctic fox (Alopex lagopus) and Chinese raccoon dog (Nyctereutes procyonoides procyonoides) genomes by the use of fluorescence in situ hybridization (FISH). The chromosome localizations in the arctic fox are in general agreement with data obtained from comparative genome maps of the dog and the fox. However, our studies showed that the order of the loci on some chromosomes was changed during karyotype evolution. Therefore, we suggest that small intrachromosomal rearrangements took plac

    The impact of teacher's self-efficacy and classroom externalising problem behaviors on emotional exhaustion:Between- and within-person associations

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    Teaching can be a challenging profession, which puts teachers at high risk for developing burnout symptoms, such as emotional exhaustion. In this study we aim to investigate the interplay between classroom externalising problem behaviours (as a job demand), teachers’ self-efficacy (as a job resource) and emotional exhaustion over a school year. Conducting three measurements during a school year among 103 Dutch primary education teachers, we examine the sensitivity for, and the individual development of, emotional exhaustion. Findings show that emotional exhaustion, classroom externalising problem behaviours, and teachers’ self-efficacy are stable constructs in teachers. Traditional (between-person) cross-lagged panel models indicate that teachers with low levels of self-efficacy are more likely to develop emotional exhaustion during the school year, compared to their colleagues. We found no evidence that teachers confronted with classroom externalising problem behaviours were more likely to develop emotional exhaustion. Random intercept (within-person) cross-lagged panel models indicate that teachers with high levels of classroom externalising problem behaviours do not show increased emotional exhaustion at a later time point. For self-efficacy and emotional exhaustion, we could not estimate the within-person model due to limited variance in the variables. Implications of these findings and suggestions for further research were discussed

    PRNP promoter polymorphisms are associated with BSE susceptibility in Swiss and German cattle

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    BACKGROUND: Non-synonymous polymorphisms within the prion protein gene (PRNP) influence the susceptibility and incubation time for transmissible spongiform encephalopathies (TSE) in some species such as sheep and humans. In cattle, none of the known polymorphisms within the PRNP coding region has a major influence on susceptibility to bovine spongiform encephalopathy (BSE). Recently, however, we demonstrated an association between susceptibility to BSE and a 23 bp insertion/deletion (indel) polymorphism and a 12 bp indel polymorphism within the putative PRNP promoter region using 43 German BSE cases and 48 German control cattle. The objective of this study was to extend this work by including a larger number of BSE cases and control cattle of German and Swiss origin. RESULTS: Allele, genotype and haplotype frequencies of the two indel polymorphisms were determined in 449 BSE cattle and 431 unaffected cattle from Switzerland and Germany including all 43 German BSE and 16 German control animals from the original study. When breeds with similar allele and genotype distributions were compared, the 23 bp indel polymorphism again showed a significant association with susceptibility to BSE. However, some additional breed-specific allele and genotype distributions were identified, mainly related to the Brown breeds. CONCLUSION: Our study corroborated earlier findings that polymorphisms in the PRNP promoter region have an influence on susceptibility to BSE. However, breed-specific differences exist that need to be accounted for when analyzing such data

    Dual origins of dairy cattle farming - evidence from a comprehensive survey of European Y-chromosomal variation

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    BACKGROUND: Diversity patterns of livestock species are informative to the history of agriculture and indicate uniqueness of breeds as relevant for conservation. So far, most studies on cattle have focused on mitochondrial and autosomal DNA variation. Previous studies of Y-chromosomal variation, with limited breed panels, identified two Bos taurus (taurine) haplogroups (Y1 and Y2; both composed of several haplotypes) and one Bos indicus (indicine/zebu) haplogroup (Y3), as well as a strong phylogeographic structuring of paternal lineages. METHODOLOGY AND PRINCIPAL FINDINGS: Haplogroup data were collected for 2087 animals from 138 breeds. For 111 breeds, these were resolved further by genotyping microsatellites INRA189 (10 alleles) and BM861 (2 alleles). European cattle carry exclusively taurine haplotypes, with the zebu Y-chromosomes having appreciable frequencies in Southwest Asian populations. Y1 is predominant in northern and north-western Europe, but is also observed in several Iberian breeds, as well as in Southwest Asia. A single Y1 haplotype is predominant in north-central Europe and a single Y2 haplotype in central Europe. In contrast, we found both Y1 and Y2 haplotypes in Britain, the Nordic region and Russia, with the highest Y-chromosomal diversity seen in the Iberian Peninsula. CONCLUSIONS: We propose that the homogeneous Y1 and Y2 regions reflect founder effects associated with the development and expansion of two groups of dairy cattle, the pied or red breeds from the North Sea and Baltic coasts and the spotted, yellow or brown breeds from Switzerland, respectively. The present Y1-Y2 contrast in central Europe coincides with historic, linguistic, religious and cultural boundaries.Penedo, Lenstra mail
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