共查询到20条相似文献,搜索用时 0 毫秒
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G. A. Hallenbeck 《CMAJ》1970,103(12):1255-1262
During the past 40 years, after gastroenterostomy and pyloroplasty for duodenal ulcer had been replaced by partial gastrectomy in many centres, partial gastrectomy itself gave way to combinations of vagotomy with gastroenterostomy, pyloroplasty or antrectomy. Opinions differ concerning the procedure of choice and in this paper the author examines the causes of this diversity of opinion and assesses the reliability of conclusions that can be drawn about the elective treatment of duodenal ulcer today. Most reports of results from various operations have come from retrospective studies, and the causes of variability among such reports are analyzed to point out the great difficulty in making a valid judgment about the relative worth of the various operations used to treat duodenal ulcer. Results of some of the few prospective studies with randomized operations assessed blindly are then presented and note is taken of the surprising observation that greatly different operations appear to give remarkably similar results. From the data available the author develops a logical way of approaching the choice of operation for the various problems related to duodenal ulcer that require elective surgical treatment. 相似文献
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Jean Pierre 《中国实验动物学报》2005,(Z1)
Contents:Duringthe development of biological medical science,a great number of research experiments are carried out andthe various infectious animal experiments are necessary part of them.For lab animal experiments,it is necessary tochoose proper isolation equipments accordingto experiment hazardlevels.1.FunctionsAnimal isolation systemare used broadlyin laboratory research,pharmaceuticals and medical areas.The isolationsystemhas become excellent equipmentsin animal breeding,disease diagnosis… 相似文献
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Lippincott-Schwartz J 《Molecular biology of the cell》2011,22(21):3929-3932
The paradigm that the secretory pathway consists of a stable endoplasmic reticulum and Golgi apparatus, using discrete transport vesicles to exchange their contents, gained important support from groundbreaking biochemical and genetic studies during the 1980s. However, the subsequent development of new imaging technologies with green fluorescent protein introduced data on dynamic processes not fully accounted for by the paradigm. As a result, we may be seeing an example of how a paradigm is evolving to account for the results of new technologies and their new ways of describing cellular processes. 相似文献
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Complete pedigree information is a prerequisite for modern breeding and the ranking of parents and offspring for selection and deployment decisions. DNA fingerprinting and pedigree reconstruction can substitute for artificial matings, by allowing parentage delineation of naturally produced offspring. Here, we report on the efficacy of a breeding concept called "Breeding without Breeding" (BwB) that circumvents artificial matings, focusing instead on a subset of randomly sampled, maternally known but paternally unknown offspring to delineate their paternal parentage. We then generate the information needed to rank those offspring and their paternal parents, using a combination of complete (full-sib: FS) and incomplete (half-sib: HS) analyses of the constructed pedigrees. Using a random sample of wind-pollinated offspring from 15 females (seed donors), growing in a 41-parent western larch population, BwB is evaluated and compared to two commonly used testing methods that rely on either incomplete (maternal half-sib, open-pollinated: OP) or complete (FS) pedigree designs. BwB produced results superior to those from the incomplete design and virtually identical to those from the complete pedigree methods. The combined use of complete and incomplete pedigree information permitted evaluating all parents, both maternal and paternal, as well as all offspring, a result that could not have been accomplished with either the OP or FS methods alone. We also discuss the optimum experimental setting, in terms of the proportion of fingerprinted offspring, the size of the assembled maternal and paternal half-sib families, the role of external gene flow, and selfing, as well as the number of parents that could be realistically tested with BwB. 相似文献
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Martin F. J. Taylor Paul S. Sattler Megan Evans Richard A. Fuller James E. M. Watson Hugh P. Possingham 《Biodiversity and Conservation》2011,20(4):767-777
Despite the growing numbers of threatened species and high levels of spending on their recovery worldwide, there is surprisingly
little evidence about which conservation approaches are effective in arresting or reversing threatened species declines. Using
two government data sets, we examined associations between population trends for 841 nationally-threatened terrestrial species
in Australia, and four measures of conservation effort: (a) how much their distribution overlaps with strictly protected areas
(IUCN I–IV), (b) and other protected areas (IUCN V–VI), (c) the number of recovery activities directed at the species, and
(d) numbers of natural resource conservation activities applied in areas where populations of the threatened species occur.
We found that all populations of 606 (72%) species were in decline. Species with greater distributional overlap with strictly
protected areas had proportionately more populations that were increasing or stable. This effect was robust to geographic
range size, data quality differences and extent of protection. Measures other than strictly protected areas showed no positive
associations with stable or increasing trends. Indeed, species from regions with more natural resource conservation activities
were found to be more likely to be declining, consistent with differential targeting of such generalised conservation activities
to highly disturbed landscapes. Major differences in trends were also found among the different jurisdictions in which species
predominantly occurred, which may be related to different legislative protections against habitat destruction. Although we
were not able to test causation, this research corroborates other evidence that protected areas contribute to the stabilization
or recovery of threatened species, and provides little empirical support for other conservation approaches. 相似文献
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