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An estimate of effective hydration temperature (EHT) is needed for chronological use of obsidian hydration data. This paper describes a method for calculating EHT by the practicing archaeologist, replacing three techniques that are in general use today: estimates based on mean temperature, numerical integration of models of diurnal and annual temperature variations, and use of temperature cells. The hydration (or diffusion) coefficient of obsidian is a function of temperature and thus is time varying, while the classic quadratic law of hydration is not valid for time-varying diffusion coefficients. This paper presents a mathematical solution to the case of a time-varying hydration coefficient, based on diffusion theory, with a concise definition of EHT. It is shown that the results are not affected by concentration dependence in the diffusion coefficient. A computer program to compute the rigorous solution is described, and data are presented to explore the resulting range of variation. That use of the Lee equation to compute EHT is not appropriate for obsidian hydration studies is evident from the data presented. The effects of paleoclimatic variation are estimated, and an algebraic best fit equation and worksheet are provided as practical aids to the archaeologist. 相似文献
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Kenneth Dorter 《European Legacy》2004,9(2):163-172
The question whether the fusion of the musical traditions of different cultures is a good thing or not is irrelevant in practical terms, since there is no realistic possibility of preventing it, but the advantages and disadvantages that the process brings are worth considering nevertheless. The loss of diversity that results when one tradition is overwhelmed by its contact with a more influential one is not redressed by the increased variety that comes about within the dominant tradition, since the latter are variations within a tradition rather than traditions of distinct origins. But the common denominator that allows different traditions to interact meaningfully with one another points to the ability of music to bring us in touch with our common humanity. 相似文献
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Central to climate justice is the question of who will pay for the mitigation and adaptation efforts needed as the climate crisis worsens, particularly in countries that bear little responsibility for global greenhouse gas emissions. Climate finance is a complex set of mechanisms intended to address this concern. World-systems theory has long understood international development assistance as a tool that reproduces spatial dependency between states. In this paper, we ask whether climate finance follows the expectations of world-systems theory and reproduces relationships of dependency, or if it instead advances climate justice and challenges spatial dependency in the world-system. Through this analysis, we consider the implications of climate finance for world-systems theory. We use recent empirical data to ask whether climate finance follows or challenges world-systems theory expectations, focusing on five areas: (1) spatial flows of climate finance between the core, semi-periphery, and periphery; (2) the governance of climate finance institutions; (3) the types of projects supported by climate finance; (4) the relationship of projects to dominant systems of extraction, production, and consumption; and (5) the agency of peripheral state and non-state actors in shaping climate finance in relation to their interests. Taken together, we argue that climate finance in many ways reproduces relationships of dependency, though potential avenues exist for contesting this unequal balance of power and for advocating for climate justice. This case illustrates the need to approach analyses of dependency in a nuanced way, interrogating specific processes through which dependency is produced and contested across scales. 相似文献
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《Journal of Atmospheric and Terrestrial Physics》1987,49(11-12):1107-1117
Ionospheric modification by high power radio waves and by chemical releases are combined in a theoretical study of ionospheric focused heating. The release of materials which promote electron-ion recombination creates a hole in the bottomside ionosphere. The ionospheric hole focuses high power radio waves from a ground-based transmitter to give a 20 dB or greater enhancement in power density. The intense radio beam excites atomic oxygen by collisions with accelerated electrons. Airglow from the excited oxygen provides a visible trace of the focused beam. The large increase in the intensity of the radio beam stimulates new wave-plasma interactions. Numerical simulations show that the threshold for the two-plasmon decay instability is exceeded. The interaction of the pump electromagnetic wave with the backward plasmon produces a scattered electromagnetic wave at 3/2 the pump frequency. The scattered wave provides a unique signature of the two-plasmon decay process for ground-based detection. 相似文献
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Richard Bellamy 《History of European Ideas》2013,39(5):753-756
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BENJAMIN J. COHEN 《International affairs》2008,84(3):455-470
This article examines the dynamics of power and rule‐setting in the international monetary system. It begins with a brief discussion of the meaning of power in international monetary relations, distinguishing between two critical dimensions of monetary power: autonomy and influence. Major developments have led to a greater diffusion of power in monetary affairs, both among states and between states and societal actors. But the diffusion of power has mainly been in the dimension of autonomy, rather than influence, meaning that leadership in the system has been dispersed rather than relocated—a pattern of change in the geopolitics of finance that might be called leaierless diffusion. The pattern of leaderless diffusion, in turn, is generating greater ambiguity in prevailing governance structures. Rule‐setting in monetary relations increasingly relies not on negotiations among a few powerful states but, rather, on the evolution of custom and usage among growing numbers of autonomous agents. Impacts on governance structures can be seen on two levels: the individual state and the global system. At the state level, the dispersion of power compels governments to rethink their commitment to national monetary sovereignty. At the systemic level, it compounds the difficulties of bargaining on monetary issues. More and more, formal rules are being superseded by informal norms that emerge, like common law, not from legislation or statutes but from everyday conduct and social convention. 相似文献
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Gissur
. Erlingsson 《Political Geography》2008,27(8):857-874
Theoretical expectations predict instances of party formation to be unusual. It is therefore puzzling that new ‘non-national’ parties became increasingly common in Swedish local councils between 1973 and 2002. This article sets out to answer why party formation became an increasingly popular strategy throughout these years. I show that previous research has not provided satisfactory answers, and argue that existing theories are of limited use explaining this development. It is suggested that a diffusion mechanism may explain why new parties became increasingly common in Swedish local councils. Theoretically, it is argued that an entrepreneur who creates a new party inspires potential entrepreneurs in neighboring municipalities to repeat this at later points in time. A geographical clustering of municipalities where these parties exist is therefore expected. Support is found for this assertion. The result is important since it outperforms the alternative ‘local contextual’, socioeconomic hypotheses previously tested in this empirical setting. 相似文献
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The authors examine the extent to which the decision to emigrate can be thought of as an innovation spreading across time and space. A methodology is developed based on aggregated data and is used to examine nineteenth-century emigration from the Upper Dalarna region of west central Sweden 相似文献
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刘少奇在长期从事和领导中国新闻事业的实践中,作出过许多精辟的论述,形成了内容丰富、独具特色的新闻观点.刘少奇的新闻观,是对马克思主义新闻理论,尤其是毛泽东新闻思想的丰富和发展,对新时期新闻工作仍然有着重要的指导意义. 相似文献
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Rodney Smith 《Australian journal of political science》1989,24(1):56-67
‘Interest’ is a central concept in contemporary liberal political theory. Much of this discussion is marked by related confusions between ‘interest’ and ‘actions‐in‐interests’ and between ‘subjective’ and ‘objective’ interests. These confusions are damaging, since liberal theorists are ostensibly firmly opposed to treating objective interests as politically relevant, but they inevitably finish up admiting the relevance of some form of objective interests. They do this by limiting valid interest judgements to those which are rational, or which favour future over present interests, or which are made post facto, or which favour public over individual interests. This admission of objective interests into liberal theory has important implications for the way in which liberal theorists conceive of relationships between the liberal democratic state and its citizens. In particular, it seriously undermines the democratic element in contemporary liberal democratic theories of political representation. 相似文献
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Pannese E 《Journal of the history of the neurosciences》1999,8(2):132-140
The black reaction, invented in 1873 by Camillo Golgi (1843-1926, was the first technique to reveal neurons in their entirety, i.e. with all their processes. This important development passed unnoticed at first and only received wide international attention after a long delay. The Golgi stain was widely employed for almost thirty years and was directly responsible for major advances in our knowledge of the microscopic anatomy of the nervous system, as well as in other fields of study. In the hands of other researchers, the black reaction provided vital evidence that helped to establish the neuron theory. The Golgi stain was almost forgotten in the period between the two World Wars, but the introduction of the electron microscope to neurocytological resarch revived its use around the middle of the twentieth century. Today, the black reaction is still used extensively not only in combination with electron microscopy, but also as an autonomous technique in studies on the evolution, ontogeny, and organization of the nervous system. 相似文献