805 research outputs found

    Causas de anestro em bovinos da microrregião de Juiz de Fora- MG.

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    Anais do Workshop sobre embriões bovinos produzidos in vitro: perspectivas de utilização e possíveis impactos na pecuária brasileira.

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    bitstream/item/82562/1/Anais-do-workshop.pd

    Desenvolvimento de embriões produzidos in vitro da Raça Gir e Holandesa criadas em clima tropical.

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    bitstream/item/89798/1/BOP-22.pd

    Finite elements versus experimental for a CFRP structure

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    The work presented herein is part of a project focused on the optimization of a carbon fibre reinforced epoxy matrix (CFRP) structure. The implemented process resorts to finite elements modelling in order to evaluate the performance of the analysed structure. To validate the finite elements model at the basis of the optimization process a scale model prototype of the composite structure was built and tested under similar loading conditions. The experimental results determined were then compared with those obtained from simulations of a built numerical model depicting the experimental set up and taken into account the mechanical and geometrical properties of the composite part, the used accessories, the interface between parts and production constraints.Portuguese Foundation for Science and Technology under project UID/CTM/50025/2013 and scholarship SFRH / BD / 51106 / 201

    Punção folicular e produção in vitro de embriões em vacas Gir submetidas a estimulação hormonal.

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    bitstream/item/89781/1/BOP-14.pd

    Field-induced Ordering in Critical Antiferromagnets

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    Transfer-matrix scaling methods have been used to study critical properties of field-induced phase transitions of two distinct two-dimensional antiferromagnets with discrete-symmetry order parameters: triangular-lattice Ising systems (TIAF) and the square-lattice three-state Potts model (SPAF-3). Our main findings are summarised as follows. For TIAF, we have shown that the critical line leaves the zero-temperature, zero -field fixed point at a finite angle. Our best estimate of the slope at the origin is (dTc/dH)T=H=0=4.74±0.15(dT_c/dH)_{T=H=0} = 4.74 \pm 0.15. For SPAF-3 we provided evidence that the zero-field correlation length diverges as ξ(T0,H=0)exp(a/Tx)\xi(T \to 0, H=0) \simeq \exp (a/T^{x}), with x=1.08±0.13x=1.08 \pm 0.13, through analysis of the critical curve at H0H \neq 0 plus crossover arguments. For SPAF-3 we have also ascertained that the conformal anomaly and decay-of-correlations exponent behave as: (a) H=0: c=1,η=1/3c=1, \eta=1/3; (b) H0:c=1/2,η=1/4H \neq 0: c=1/2, \eta=1/4.Comment: RevTex, 7 pages, 4 eps figures, to be published in Phys. Rev.

    Embriões F1 (Hol x Gir) produzidos in vitro utilizados a fresco em rebanhos leiteiros comerciais e controlado.

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    RESUMO - A importância do (F1) para o Brasil é notória, associando rusticidade e produtividade, porém é grande a dificuldade do produtor em manter seu rebanho nesse grau de sangue. No laboratório da Embrapa Gado de Leite em Juiz de Fora, MG foram produzidos in vitro 266 embriões (F1), a partir de complexos cumulus-oócitos (CCO's) de vacas Gir puncionadas e fecundadas com sêmen de touro Holandês. Destes, 53 embriões foram transferidos a fresco para receptoras de rebanhos comerciais de uma Cooperativa da Zona da Mata, MG, enquanto 72 embriões foram inovulados em rebanho controlado da Embrapa Campo Experimental de Coronel Pacheco. A produção de embriões F1 por fecundação in vitro apresentou taxa de produção de blastocisto de 15,58%. A taxa de gestação obtida foi de 26,4% no rebanho comercial e 40,2% no rebanho da Embrapa. Considerando-se o nascimento de 50% de machos e fêmeas, conclui-se que em rebanhos de 100 vacas seriam obtidas 13 fêmeas (13% de reposição) nos rebanhos comerciais e 20 fêmeas (20% de reposição) no rebanho da Embrapa. Foram muitas as dificuldades de operacionalização para o uso de dessa biotecnologia que requer um mínimo de escrituração zootécnica, controle sanitário, observação de cios e manejo reprodutivo. ABSTRACT - The importance of (F1) to Brazil is notable, associating productivity and rusticity, it is difficult to the producer maintaining the herd in this blood degree. In Embrapa's Gado de Leite, laboratory in the city of Juiz de Fora, M.G., 266 embryos (F1) were produced in vitro from the oocytes of Gir cows, punched and fecundated with Holstein Friesan bull semen. Out of these, 53 embryos were transferred at natural into recipient cows in the commercial herds indicated by the technicians of a great cooperative of Zona da Mata's area, 72 embryos were transferred into recipients of Embrapa's herds under nutritional and sanitary controls. The remainder 139 embryos were frozen due to the lack of adequate recipient cows. The production of F1 embryos through in vitro fecundation of oocytes from Gir cows with semen from Holstein Friesan bull blastocist production rate of 15,58 %. The pregnance rate obtained was 26.4% in the cows from the commercial herds and 40.2% in the herds of Embrapa Gado de Leite. Considering the birth of 50% female cows, we can estimate a replacement annual rate of 13% (26.2% for gestation) for commercial herds and 20% (40% for pregnancy) for the controlled herd. There were many difficulties encountered in the operation, such as (i) the low level of adoption of technology; (ii) little investment in feeding, handling and sanity conditions of the herds; (iii) conditions capable to compromising the utilization of embryos, which requires a minimum of structure in terms of zoo-technical documentation, observation of rutting and reproduction management
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