共查询到20条相似文献,搜索用时 15 毫秒
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M. K. Mani 《BMJ (Clinical research ed.)》1971,3(5771):407-408
Sodium nitroprusside is a readily available, powerful hypotensive agent. It was administered intravenously in four cases when all other available hypotensive agents had failed, and blood pressure was controlled promptly and with no side effects. This is a valuable drug and deserves wider use. 相似文献
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Androgenesis Revisited 总被引:1,自引:0,他引:1
José M. Seguí-Simarro 《The Botanical review》2010,76(3):377-404
Androgenesis can be defined as the set of biological processes leading to an individual genetically coming exclusively from a male nucleus. Androgenesis was traditionally considered as the spontaneous, in vivo development of a male-derived haploid embryo from a fertilized egg where the female nucleus is eliminated. However, at present it is also possible to generate androgenic haploids/doubled haploids through in vitro microspore embryogenesis and by in vitro meiocyte-derived callogenesis. These three androgenic alternatives clearly differ in the inducible stage, but lead to the same final haploid or doubled haploid product. Whereas microspore embryogenesis is widely studied and applied, the other two routes are much less known. In this paper, the evidence accounting for the existence of these three alternative pathways is revised, as well as the mechanisms potentially involved in their induction. Their differences and similarities are discussed from a biological perspective, leading to the notion that they might represent an ancient survival mechanism triggered by similar factors. 相似文献
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In Disney/Pixar's phenomenally popular animated film Finding Nemo (Stanton, 2003), one of the central themes of fish welfare was highlighted when the moorish idol, Gill, commented, “Fish aren't meant to be kept in a box, kid. It does things to you.” The notion that fish might have the capacity to suffer in captivity (Chandroo, Duncan, & Moccia, 2004a, 2004b) links to the larger question of sentiency, which remains a fundamental tenet when justifying concerns for nonhuman animal welfare (Dawkins, 2006; Huntingford et al., 2006). Although terrestrial nonhuman-animal welfare has been discussed and explored for many years, the development of aquatic animal welfare concepts and approaches remains relatively new and beyond public awareness (Braastad, Damsgård, & Juell, 2006; Broom, 2007; Farmed Animal Welfare Council, 1996; Fisheries Society of the British Isles, 2002; Håstein, Scarfe, & Lund, 2005; Iwama, 2007; Schreck, 1981). 相似文献
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J. Donald Hughes 《Journal of the history of biology》2011,44(1):43-57
The image of the classical Mediterranean environment of the Greeks and Romans had a formative influence on the art, literature, and historical perception of modern Europe and America. How closely does is this image congruent with the ancient environment as it in reality existed? In particular, how forested was the ancient Mediterranean world, was there deforestation, and if so, what were its effects? The consensus of historians, geographers, and other scholars from the mid-nineteenth century through the first three quarters of the twentieth century was that human activities had depleted the forests to a major extent and caused severe erosion. My research confirmed this general picture. Since then, revisionist historians have questioned these conclusions, maintaining instead that little environmental damage was done to forests and soils in ancient Greco-Roman times. In a reconsideration of the question, this paper looks at recent scientific work providing proxy evidence for the condition of forests at various times in ancient history. I look at three scientific methodologies, namely anthracology, palynology, and computer modeling. Each of these avenues of research offers support for the concept of forest change, both in abundance and species composition, and episodes of deforestation and erosion, and confirms my earlier work. 相似文献
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