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This paper examines the methodology used by Kepler to discover a quantitative law of refraction. The aim is to argue that this methodology follows a heuristic method based on the following two Pythagorean principles: (1) sameness is made known by sameness, and (2) harmony arises from establishing a limit to what is unlimited. We will analyse some of the author's proposed analogies to find the aforementioned law and argue that the investigation's heuristic pursues such principles.  相似文献   

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南极无冰区古气候与冰盖进退历史研究进展   总被引:1,自引:0,他引:1  
环南极洲无冰区就是随着气候变暖、冰川后退而出现,是研究南极乃至全球的自然环境演化历史的理想场所。本文主要介绍了国内外学者在恢复无冰区古气候、古环境演变与冰盖进退历史方面所采用的主要手段和方法,并着重论述了近几年关于南极半岛、西南极和东南极环海岸一带无冰区的冰川作用历史与古气候研究成果,指出了目前研究中所存在的问题,提出了以后研究中所要解决的问题。  相似文献   

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Ebola viruses belong to the family Filoviridae, which are among the most virulent infectious agents known. These viruses cause acute, and frequently fatal, hemorrhagic fever in humans and nonhuman primates. Currently, no vaccines or treatments are available for human use. This review describes Ebola viruses, with a particular focus on the status of research efforts to develop vaccines and therapeutics and to identify the immune mechanisms of protection.  相似文献   

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This paper argues that, contrary to the claims of Alan Chalmers, Boyle understood his experimental work to be intimately related to his mechanical philosophy. Its central claim is that the mechanical philosophy has a heuristic structure that motivates and gives direction to Boyle's experimental programme. Boyle was able to delimit the scope of possible explanations of any phenomenon by positing both that all qualities are ultimately reducible to a select group of mechanical qualities and that all explanations of natural phenomena are to be in terms of the operations of machines and are to appeal only to qualities that are already familiar. This is illustrated by his investigations into the Torricellian experiment. Boyle's explanation of the elevation of the mercurial cylinder by appeal to the spring of the air was an intermediate mechanical explanation. Boyle was convinced that the spring of the air was ultimately reducible to the mechanical qualities. This in turn had implications for his research into the cause of respiration. In a move that was both parsimonious and consistent with the broad requirements of the mechanical philosophy, Boyle was able to solve the problem of the cause of the inflow of air into the lungs by appeal to his research in pneumatics. This application of a mechanical explanation in pneumatics to physiology is just what one would expect if the mechanical philosophy was as universal as Boyle claimed it to be. Therefore, far from Boyle's experiments having a life of their own, they were clearly directed by and understood in terms of the mechanical philosophy.  相似文献   

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We can distinguish ‘mechanical’ in the strict sense of the mechanical philosophers from ‘mechanical’ in the common sense. My claim is that Boyle's experimental science owed nothing to, and offered no support for, the mechanical philosophy in the strict sense. The attempts by my critics to undermine my case involve their interpreting ‘mechanical’ in something like the common sense. I certainly accept that Boyle's experimental science was productively informed by mechanical analogies, where ‘mechanical’ is interpreted in a common sense. But this leaves my original claim untouched and, in the main, unchallenged.  相似文献   

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ABSTRACT

Historians have portrayed the papal bull Coeli et terrae (1586) as a significant turning point in the history of the Catholic Church’s censorship of astrology. They argue that this bull was intended to prohibit the idea that the stars could naturally incline humans towards future actions, but also had the effect of preventing the discussion of other forms of natural astrology including those useful to medicine, agriculture, and navigation. The bull, therefore, threatened to overturn principles established by Thomas Aquinas, which not only justified long-standing astrological practices, but also informed the Roman Inquisition’s attitude towards this art. The promulgation of the bull has been attributed to the ‘rigour’ of the incumbent pope, Sixtus V. In this article I revise our understanding of this bull in two ways. First, I reconsider the Inquisition’s attitude towards astrology in the mid-sixteenth century, arguing that its members promoted a limited form of Thomist astrology that did not permit the doctrine of inclination. Second, using Robert Bellarmine’s unpublished lectures discussing Aquinas’s views of astrology, I suggest that this attitude was common during the sixteenth century, and may have been caused by the crisis of Renaissance astrology precipitated by the work of Giovanni Pico.  相似文献   

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Lambert冰川流域物质平衡和南极冰盖变化   总被引:2,自引:0,他引:2  
对Lambert冰川流域的现场考察资料和浅冰芯研究结果显示,该流域东侧和西侧积累速率分布和过去几十年的变化具有明显差异:东侧平均积累速率较西侧高;近50年东侧处于增加状态,西侧则为明显减小。冰量平衡计算表明,该冰川流域目前处于物质正平衡状态,因而冰盖将趋于增厚。据现有资料估计分析,整个南极冰盖处于微弱负平衡。如果南极地区气候变暖,物质平衡将向正平衡方向发展,因而不会引起海平面上升。但是西南极冰盖的不稳定性可能随气候持续变暖而增强,成为引起海平面上升的最重要潜在因素。  相似文献   

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Zusammenfassung Die Zahl der diploiden Chromosomen vonMarmota caligata undM. flaviventris ist 42 in Bevölkerungen der nördlichen und südlichen Verbreitungsgebiete beider Spezies. Ein Vergleich zwischen den bisher veröffentlichten Informationen überMarmota-Chromosomen mit Angaben über ihre Morphologie, Ekologie, Zoogeographie legt nahe, dass die ursprüngliche Chromosomenzahl 2n 38–40 war.

Supported by National Science Foundation Grant Nos. GB-3251 and GB-5428, and by a National Academy of Sciences US-USSR Exchange Fellowship. We thank Dr.D. L. Pattie for generously providing the specimen ofM. flaviventris and Mrs.Gabriele Forrester for preparation of theM. c. nivaria chromosomes.  相似文献   

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