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141.
FC Varago VS Moutacas BC Carvalho RV Serapião F Vieira H Chiarini‐Garcia FZ Brandão LS Camargo M Henry MA Lagares 《Reproduction in domestic animals》2014,49(5):839-844
The aim of this work was to evaluate the efficiency of the cryoprotectants dimethylformamide and ethylene glycol for cryopreservation of ovine embryos using vitrification and conventional freezing. The recovered embryos were distributed randomly in three treatment groups: Gr. 1: conventional freezing (n = 44), Gr. 2: vitrification with ethylene glycol (n = 39) and Gr. 3: vitrification with dimethylformamide (n = 38). Quality of fresh embryos in control group as well as of frozen and vitrified embryos was examined by three methodologies: staining with propidium iodide and Hoechst 33258 and evaluation under fluorescent microscopy, evaluation of re‐expansion and hatching rates after culture, and determination of apoptotic index with TUNEL technique. It was established that re‐expansion rate in all treatment groups was similar. In the same time, hatching rates were higher in Gr. 1 (40.5%) and Gr. 2 (35.3%) in comparison with Gr. 3 (15.5%, p < 0.05). The number of dead cells in vitrified embryos of Gr. 2 and Gr. 3 was higher (42.6 ± 26.2 and 63.2 ± 34.65, respectively) in comparison with Gr. 1 (conventional freezing, 10.1 ± 8.5, p < 0.05). Embryos vitrified with dimethylformamide included the same quality of apoptotic cells that Gr. 1 (conventional freezing) and fresh embryos. In conclusion, the dimethylformamide and ethylene glycol used as cryoprotectant to vitrify ovine embryos, in the concentrations and exposition time tested in this work, were not as efficient as the conventional freezing for cryopreservation of ovine embryos Thus, the conventional freezing with ethylene glycol was the most efficient method to cryopreserve ovine embryos in comparison with vitrification. 相似文献
142.
P.B. English 《New Zealand veterinary journal》2013,61(3):97-114
A 3-week-old Thoroughbred colt was presented for weakness and cyanosis. A pansystolic regurgitant murmur and other physical findings suggested that the foal developed pulmonary oedema as a consequence of congenital heart disease. A large atria1 septal defect, a high ventricular septal defect and dysplasia of the atrioventricular valves were visualised echocardiographically. A persistent common atrioventricular canal was observed at necropsy. 相似文献
143.
144.
J. Colby Torbett Roland K. Roberts James A. Larson Burton C. English 《Precision Agriculture》2007,8(3):127-137
Site-specific information technologies (IT) provide knowledge about the spatial variability within a field to improve the
efficiency of inputs through variable-rate (VR) applications. Identifying factors that influence farmers’ perceptions of the
importance of precision farming (PF) technologies in improving the efficiency of phosphorus (P) and potassium (K) fertilizer
applications can help to determine why different groups of farmers adopt PF. Knowing these factors can be useful in targeting
specific groups of farmers to adopt PF and increase fertilizer efficiency to meet crop needs and reduce P and K losses to
the environment. Data were obtained from a 2001 mail survey of cotton (Gossypium hirsutum L.) farmers in six southeastern states in the United States of America. Ordered logit analysis was used to evaluate the level
of importance to those who had adopted PF technologies placed on such technologies they had used to improve the efficiency
of P and K applications. Results showed that such farmers found soil sampling by management zone or on a grid, and on-the-go
sensing most important. Precision farmers who used mapping and remote sensing found PF technologies least important. Older
precision farmers who rented larger proportions of their land and used computers for farm management were more likely than
other precision farmers to place greater importance on PF technologies in improving the efficiency of P and K applications. 相似文献
145.
Development of the Rhizobium-legume symbiosis is controlled by the host plant, although the underlying mechanisms have remained obscure. A mutant in the annual legume Medicago truncatula exhibits an increase of more than an order of magnitude in the number of persistent rhizobial infections. Physiological and genetic analyses indicate that this same mutation confers insensitivity to the plant hormone ethylene for multiple aspects of plant development, including nodulation. These data support the hypothesis that ethylene is a component of the signaling pathway controlling rhizobial infection of legumes. 相似文献
146.
The Atmosphere Structure Instrument on the Galileo probe detected wavelike temperature fluctuations superimposed on a 700-kelvin temperature increase in Jupiter's thermosphere. These fluctuations are consistent with gravity waves that are viscously damped in the thermosphere. Moreover, heating by these waves can explain the temperature increase measured by the probe. This heating mechanism should be applicable to the thermospheres of the other giant planets and may help solve the long-standing question of the source of their high thermospheric temperatures. 相似文献