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An electroimmobilisation device has been developed to facilitate the automated shearing of sheep, but there is little information on its effects on the body. We have studied its effects on the cardiovascular system and on intermediary metabolism in sheep. Electroimmobilisation caused statistically significant increases in mean arterial pressure, heart rate, cardiac output, renal and hepatic and hindquarter glucose and lactate flux, organ and whole body oxygen flux, hindquarter blood flow and core temperature and decreases in arterial and posterior vena cava blood pH, renal and hepatic blood flow and PaCO2. Notably, no change occurred in PaO2. The metabolic changes demonstrated the capacity of sheep to respond to the increased muscular and cardiovascular work induced by electroimmobilisation. Pulmonary function was not compromised during electroimmobilisation as judged from blood gas changes, and the acid/base changes were rapidly reversed after electroimmobilisation. The recovery to control conditions for all perturbations generally took no longer than 30 min, consistent with a rapid and physiologically adequate reversal by the animal's homeostatic mechanisms. 相似文献
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The probability that two stratigraphic events are in a particular order in a section in which they occur in sequence is p. Because of finite sampling, statistical techniques are used to calculate the parameters p' and p(l), which express the uncertainty of our knowledge of p; p' is the measured value of the maximum likelihood estimator of p and p(l) is the lower end point of the confidence interval on which p must lie. The most reliable sequence for stratigraphic correlation is obtained by maximizing the parameter p' (1-p(l)) between pairs of events. 相似文献
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Abstract CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6½-year-old female Flat-coated Retriever. PATHOLOGICAL FINDINGS: Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP). DIAGNOSIS: The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass. CLINICAL RELEVANCE: This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy. 相似文献
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The successful development of phenology models from field studies depends on many factors, some of which are entirely under the control of pest managers. For example, one such factor is the choice of method for calculating thermal units. In this study, we have demonstrated that four methods for calculating thermal units provided for acceptable predictions of one phenological event of one insect species, while another method for calculating thermal units did not. The measure of central tendency (mean or median) that is used to estimate lower developmental temperatures and required thermal summations is another factor that pest managers can control when developing phenology models from field studies. Here, we show that predictions that were made when using phenology models based on median lower developmental temperatures and median required thermal summations were superior to predictions that were made when using phenology models based on mean lower developmental temperatures and mean required thermal summations. The use of bootstrap vs. non-bootstrap estimates of lower developmental temperatures and required thermal summations is yet another factor that pest managers can control when developing phenology models from field studies. In this study, we found that calculating and using bootstrap estimates of lower developmental temperatures and required thermal summations in phenology models did not improve the predictions of one phenological event for one insect species. The implications of these and other findings are discussed. 相似文献
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JEP Santos TR Bilby WW Thatcher CR Staples FT Silvestre 《Reproduction in domestic animals》2008,43(S2):23-30
Cattle are fed moderate amounts of long chain fatty acids (FA) with the objective to enhance lactation and growth; however, recent interest on lipid feeding to cows has focused on reproduction, immunity and health. Increasing the caloric density of the ration by fat feeding has generally improved measures of cow reproduction, but when milk yield and body weight losses were increased by fat supplementation, positive effects on reproduction were not always observed. Feeding fat has influenced reproduction by altering the size of the dominant follicle, hastening the interval to first postpartum ovulation in beef cows, increasing progesterone concentrations during the luteal phase of the oestrous cycle, modulating uterine prostaglandin (PG) synthesis, and improving oocyte and embryo quality and developmental competence. Some of these effects were altered by the type of FA fed. The polyunsaturated FA of the n-6 and n-3 families seem to have the most remarkable effects on reproductive responses of cattle, but it is not completely clear whether these effects are mediated only by them or by other potential intermediates produced during rumen biohydrogenation. Generally, feeding fat sources rich in n-6 FA during late gestation and early lactation enhanced follicle growth, uterine PG secretion, embryo quality and pregnancy in cows. Similarly, feeding n-3 FA during lactation suppressed uterine PG release, and improved embryo quality and maintenance of pregnancy. Future research ought to focus on methods to improve the delivery of specific FA and adequately powered studies should be designed to critically evaluate their effects on establishment and maintenance of pregnancy in cattle. 相似文献
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Estimation of average Cenozoic sedimentation rates for the Atlantic, Indian, and Pacific oceans indicates global synchronous fluctuations. Paleocene-early Eocene and late Eocene-early Miocene rates are only a fraction of middle Eocene and middle Miocene-Recent rates. These changes must reflect significantly different modes of continental weathering, which may be due to alternate states of atmospheric circulation marked by reduction of global precipitation. 相似文献
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Cultivation of fungi for food by fungus-growing ants (Attini: Formicidae) originated about 50 million years ago. The subsequent evolutionary history of this agricultural symbiosis was inferred from phylogenetic and population-genetic patterns of 553 cultivars isolated from gardens of "primitive" fungus-growing ants. These patterns indicate that fungus-growing ants succeeded at domesticating multiple cultivars, that the ants are capable of switching to novel cultivars, that single ant species farm a diversity of cultivars, and that cultivars are shared occasionally between distantly related ant species, probably by lateral transfer between ant colonies. 相似文献
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Sediment accumulation rate curves from 95 drilled cores from the Pacific basin and sea-level curves derived from continental margin seismic stratigraphy show that high biogenous sediment accumulation rates correspond to low eustatic sea levels for at least the last 48 million years. This relationship fits a simple model of high sea levels producing lower land/sea ratios and hence slower chemical erosion of the continents, and vice versa. 相似文献
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AIMS: To describe the histopathological lesions of a new canine disease characterised by progressive ataxia, head tremor and seizures, and to deduce the cause of the lesions. METHODS: Formalin-fixed tissues were processed into paraffin wax and epoxy resin for light and transmission electron microscopy of variously stained tissue sections. RESULTS: Significant lesions relevant to the disease were found only in the brain. They consisted of hypoplasia of the cerebellum and the presence of large pale inclusions in the perikaryon of neurons in the neocortex and in macrophages. The inclusion material was not compartmentalised and did not stain for carbohydrate, mucopolysaccharide or lipid. This material displaced nuclei to the periphery of the cells where they were seen as basophilic distorted crescent-shaped structures. CONCLUSIONS: The inclusions were probably made of polymerised protein similar, though not identical, to those of Pick, Lewy and Collins bodies that characterise a variety of chronic neurodegenerative diseases of humans. A genetic basis to this disease was considered probable. 相似文献