321 research outputs found

    Fertility of frozen-thawed stallion semen cannot be predicted by the currently used laboratory methods

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    The aim of the project was to use current simple and practical laboratory tests and compare results with the foaling rates of mares inseminated with commercially produced frozen semen. In Exp. 1, semen was tested from 27 and in Exp. 2 from 23 stallions; 19 stallions participated in both experiments. The mean number of mares per stallion in both experiments was 37 (min. 7, max. 121). Sperm morphology was assessed and bacterial culture performed once per stallion. In Exp. 1, progressive motility after 0, 1, 2, 3, and 4 h of incubation using light microscopy, motility characteristics measured with an automatic sperm analyzer, plasma membrane integrity using carboxyfluorescein diacetate/propidium iodide (CFDA/PI) staining and light microscopy, plasma membrane integrity using PI staining and a fluorometer, plasma membrane integrity using a resazurin reduction test, and sperm concentration were evaluated. In Exp. 2, the same tests as in Exp. 1 and a hypo-osmotic swelling test (HOST) using both light microscopy and a fluorometer were performed immediately after thawing and after a 3-h incubation. Statistical analysis was done separately to all stallions and to those having ≄ 20 mares; in addition, stallions with foaling rates < 60 or ≄ 60% were compared. In Exp. 1, progressive motility for all stallions after a 2 – 4-h incubation correlated with the foaling rate (correlation coefficients 0.39 – 0.51), (p < 0.05). In stallions with > 20 mares, the artificial insemination dose showed a correlation coefficient of -0.58 (p < 0.05). In Exp. 2, the HOST immediately after thawing showed a negative correlation with foaling rate (p < 0.05). No single test was consistently reliable for predicting the fertilizing capacity of semen, since the 2 experiments yielded conflicting results, although the same stallions sometimes participated in both. This shows the difficulty of frozen semen quality control in commercially produced stallion semen, and on the other hand, the difficulty of conducting fertility trials in horses

    Europium-based high-temperature superconductors studied by x-ray diffraction and 151Eu Mössbauer spectroscopy

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    Isotropic powders and magnetically aligned crystallites of EuBa2Cu3O7−ή (1:2:3) and europium-doped Bi2Sr2CaCu2O8 (2:2:1:2) were studied by means of x-ray diffraction and Eu151 Mössbauer spectroscopy. The degree of crystallite orientation of the samples and the values of the lattice constants were determined by x-ray diffraction. The Mössbauer spectra were analyzed considering the full hyperfine Hamiltonian of the nuclear states of the 21.5-keV Îł transition. The Mössbauer hyperfine parameters obtained from the superconducting and semiconducting phases are presented. A small change is seen in the Eu151 isomer shift when the oxygen deficiency ÎŽ of the 1:2:3 compound is varied. The shift can be explained by a decrease in the s-electron density due to lattice expansion. The changes in the oxidation state of the copper atoms with varying ÎŽ were determined from the Mössbauer data: The Cu(2) atoms retain their oxidation state, whereas the Cu(1) atoms adjust their valence according to the value of ÎŽ. In the 2:2:1:2 samples, the Eu concentration clearly affected the value of the electric-field gradient at the Eu nucleus. Using a standard procedure, magnetically aligned 2:2:1:2 samples were prepared. The preferred direction of the crystal c axis changed from parallel to perpendicular alignment with the external magnetic field, when the Eu concentration exceeded 20% of the Ca atoms.Peer reviewe

    Generation of Long-Lived Isomeric States via Bremsstrahlung Irradiation

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    A method to generate long-lived isomeric states effectively for Mossbauer applications is reported. We demonstrate that this method is better and easier to provide highly sensitive Mossbauer effect of long-lived isomers (>1ms) such as 103Rh. Excitation of (gamma,gamma) process by synchrotron radiation is painful due mainly to their limited linewidth. Instead,(gamma,gamma') process of bremsstrahlung excitation is applied to create these long-lived isomers. Isomers of 45Sc, 107Ag, 109Ag, and 103Rh have been generated from this method. Among them, 103Rh is the only one that we have obtained the gravitational effect at room temperature.Comment: ICAME 05 conference repor

    High level vision with the deformable pyramid

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    Une pyramide de graphes, constituant un modÚle multirésoltuion déformable est utilisée pour la reconnaissance de formes. Cette pyramide permet de décrire des formes complexes par des maillages de leur surface, elle est construite à partir d'un volume de référence. Le modÚle est ensuite déformé pour s'adapter aux données tout en conservant ses propriétés topologiques et géométriques. Cette nouvelle méthode permet l'extraction rapide, robuste et précise du modÚle dans le cadre de l'imagerie cardiaque volumique par résoance magnétique. Les potentialités de la pyramide déformable sont illustrées par l'extraction d'un modÚle du thorax et du coeur en mouvement

    Equine post-breeding endometritis: A review

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    The deposition of semen, bacteria and debris in the uterus of the mare after breeding normally induces a self-limiting endometritis. The resultant fluid and inflammatory products are cleared by 48 hours post cover. Mares that are susceptible to persistent post-breeding endometritis (PPBEM) have impaired uterine defence and clearance mechanisms, making them unable to resolve this inflammation within the normal time. This persists beyond 48 hours post-breeding and causes persistent fluid accumulation within the uterus. Mares with PPBEM have an increased rate of embryonic loss and a lower overall pregnancy rate than those without the condition. To enhance conception rates, mares at high risk need optimal breeding management as well as early diagnosis, followed by the most appropriate treatment. This article reviews the pathogenesis, diagnosis and treatment of PPBEM and the management of affected mares

    Reassembling difference? Rethinking inclusion through/as embodied ethics

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    This paper considers inclusion through the lens of embodied ethics. It does so by connecting feminist writing on recognition, ethics and embodiment to recent examples of political activism as instances of recognition-based organizing. In making these connections, the paper draws on insights from Judith Butler’s recent writing on the ethics and politics of assembly in order to re-think how inclusion might be understood and practiced. The paper has three inter-related aims: (i) to emphasize the importance of a critical reconsideration of the ethics and politics of inclusion given, on the one hand, its positioning as an organizational ‘good’ and on the other, the conditions attached to it; (ii) to develop a critique of inclusion, drawing on insights from recent feminist thinking on relational ethics, and (iii) to connect this theoretical critique of inclusion, re-considered here through the lens of embodied ethics, to assembly as a form of feminist activism. Each of these aims underpins the theoretical and empirical discussion developed in the paper, specifically its focus on the relationship between embodied ethics, the interplay between theory and practice, and a politics of assembly as the basis for a critical reconsideration of inclusion
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