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1.
An account is given of early geological researches in the Malverns, the Church Stretton area, and the Wrekin. The reconnaissance work of Murchison suggested that each of these areas had Silurian sediments, intruded by igneous rocks (called trap or syenite). The early Survey maps were compiled on this theoretical basis, with the result that the Silurian sediments were regarded as the oldest rocks in Shropshire and the Malverns. Local geologists, working in the three areas, and with sufficient time to study the exposures in detail, began to develop the idea of ‘islands’ of Precambrian (Archaean) rock (perhaps showing some stratification), having younger sediments deposited thereon. This Archaean model was taken up and actively developed, and the stratigraphical details worked out, with the island model being gradually modified. Debates were stronger between members of the ‘Archaean’ fraternity than with the Survey. Traces of trilobite remains were found by Callaway at Comley, near Caer Caradoc, and were identified by Lapworth as Olenellus, enabling the underlying Wrekin Quartzite to be established as the base of the Cambrian, in agreement with ideas developed in North America and Scandinavia. Arguments are detailed concerning the relative ages of the ‘Uriconian’ and ‘Longmyndian’ rocks, and their constituent units. Both were agreed to be Precambrian, but the evidence in terms of field mapping, in relation to the Wrekin Quartzite, is not complete. The problems of stratigraphical work in unfossiliferous rocks are displayed, and also the efforts to achieve correlations with areas such as Pembrokeshire and Anglesey are described. Though consensus has been reached on the Precambrian status of the Malvernian, Uriconian and Longmyndian rocks, radiometric age determinations and other evidence throw doubt on some aspects of the consensus, and research continues.  相似文献   

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The purpose of this work is to review, clarify, and critically analyse modern mathematical cosmology. The emphasis is upon mathematical objects and structures, rather than numerical computations. This paper concentrates on general relativistic cosmology. The opening section reviews and clarifies the Friedmann–Robertson–Walker models of general relativistic cosmology, while Section 2 deals with the spatially homogeneous models. Particular attention is paid in these opening sections to the topological and geometrical aspects of cosmological models. Section 3 explains how the mathematical formalism can be linked with astronomical observation. In particular, the informal, observational notion of the celestial sphere is given a rigorous mathematical implementation. Part II of this work will concentrate on inflationary cosmology and quantum cosmology.  相似文献   

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A detailed account is given of the development of the Archaean Controversy in Caernarvonshire and Anglesey. Sedgwick had found no base for his Cambrian in North Wales, but had intimated that some of the unfossiliferous rocks of the Lleyn Peninsula and Anglesey might be older than his Cambrian. He also described two ‘ribs’ of igneous rock: one running from Caernarvon to Bangor; the other inland, parallel to the first and crossing the Llanberis Pass at Llyn Padarn. The early Surveyors (especially Ramsay) supposed that these ‘ribs’ had altered the surrounding rocks, and the resulting ‘Altered Cambrian’ could be traced across the Menai Strait to Anglesey, where it formed the various metamorphic rocks of that island. This view (which thus denied the occurrence of Precambrian on Anglesey) was challenged by the usual coalition of ‘amateurs’ (Hicks, Hughes, Bonney, Callaway, Blake, etc.) with attempts being made to recognize a sequence of Archaean rocks in North Wales similar to that in Pembrokeshire. However, vigorous debate occurred amongst the ‘Archaean’ geologists themselves, especially about a rock at Twt Hill, Caernarvon, and about a claimed unconformity at the base of the Cambrian in the Llanberis Pass, perhaps adjacent to the Llyn Padarn ‘rib’. (This was at first regarded as a Precambrian ‘island’ like those claimed at St David's, the Malverns, etc.) Vigorous debate took place about the location of the claimed Llanberis unconformity, but the ‘Archaeans’ were united in regarding the metamorphic rocks of Anglesey as Precambrian (or Archaean). Eventually, the greywackes of Anglesey, and around Bangor and Caernarvon, were identified as Ordovician, not Cambrian. Very detailed map-work in Anglesey was carried out privately by Edward Greenly, and his results were published by the Survey in the form of a map and a high-quality Memoir. Greenly utilized for Anglesey tectonic ideas derived from his earlier fieldwork in the Scottish Highlands, so that although his mapping and stratigraphical divisions have proved to be of permanent value it is believed that his structures for Anglesey were mistaken and his stratigraphic sequence inverted. The Survey eventually abandoned its earlier (Ramsay) model of Anglesey without too much difficulty; and the igneous ‘rib’ of Llyn Padarn is now construed as an ignimbrite. However, a definite base for the Cambrian has still not been found in Caernarvonshire, and the stratigraphical evidence for the Precambrian age of the Anglesey rocks (by perceived unconformity with known Cambrian strata) remains incomplete. The study reveals the great difficulty experienced by early geologists when working in unfossiliferous rocks, the evidence from included fragments proving particularly uncertain. The paper also examines further the community of nineteenth-century British geologists, with their various factions and competing interests.  相似文献   

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All three ‘scientific’ pollsters (Crossley, Gallup and Roper) wrongly predicted incumbent President Harry Truman’s defeat in the 1948 presidential election, and thus faced a potentially serious legitimacy crisis. This ‘fiasco’ occurred at a most inopportune time. Social science was embroiled in a policy debate taking place in the halls of Congress. It was fighting a losing battle to be included, along with the natural sciences, in the National Science Foundation, for which legislation was being drafted. Faced with the failure of the polls, the Social Science Research Council (SSRC) intervened quickly to prevent social science’s adversaries from using this event to degrade further its status. After all, many social scientists considered the sample survey as the paramount tool of social research, and sampling as one of social science’s greatest innovation. Concurrently, there was an ongoing conflict among polling practitioners themselves—between advocates of probability sampling and users of quotas, like the pollsters. The SSRC committee appointed to evaluate the polling debacle managed to keep this contentious issue of sampling from becoming the centre of attention. Given the inauspicious environment in which this event happened, the SSRC did not wish to advertise the fact that the house of social science was in turmoil.  相似文献   

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In this paper, we address the emergence of horticultural practice, agents, spaces and institutions in the two urban settings of Lisbon and Porto, in Portugal, during the second half of the nineteenth century. We do so by following the networking activities of two players: the self-made horticulturist and entrepreneur José Marques Loureiro, who created, in Porto, a commercial horticultural establishment and founded the Journal of Practical Horticulture; and the agronomist Francisco Simões Margiochi, head of the gardens and green grounds department of the municipality, who created the first course on gardening and horticulture, and founded the Royal Horticultural Society, both in Lisbon. Their joint activities were aimed at establishing horticulture as an applied science and to cater simultaneously to an extended audience of citizens. They enable us to enrich the narratives on the emergence and development of horticulture in Europe by calling attention to the participation in circulatory extended networks of actors who are often absent from these accounts. Additionally, they allow a comparative assessment of the outcome of their actions at the national level, and to understand their results in terms consonant with recent historiographical trends on the co-construction of centres and peripheries.

Abbreviations: AML – Arquivo Municipal de Lisboa (Municipal Archive of Lisbon).; ANTT – Arquivo Nacional da Torre do Tombo (National Archives at Torre do Tombo).; AHCPL – Arquivo Histórico da Casa Pia de Lisboa (Historical Archive of the Casa Pia of Lisbon).; JHP – Jornal de Horticultura Practica (Journal of Practical Horticulture). Online at: http://www.fc.up.pt/fa/?p=nav&;f=html.fbib-Periodico-oa&;item=378; BSNHP - Boletim da Sociedade Nacional de Horticultura de Portugal (Bulletin of the National Society of Horticulture of Portugal).  相似文献   

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In this second part of our two-part paper we review and analyse attempts since 1950 to use information theoretic notions to exorcise Maxwell’s Demon. We argue through a simple dilemma that these attempted exorcisms are ineffective, whether they follow Szilard in seeking a compensating entropy cost in information acquisition or Landauer in seeking that cost in memory erasure. In so far as the Demon is a thermodynamic system already governed by the Second Law, no further supposition about information and entropy is needed to save the Second Law. In so far as the Demon fails to be such a system, no supposition about the entropy cost of information acquisition and processing can save the Second Law from the Demon.  相似文献   

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The recovery of the Camp Century deep ice core in 1966 – the first ice core to reach all the way through a polar ice sheet to bedrock – marked a shift from an era of United States military dominated glaciological research in Greenland to an era of climate oriented research on the island. This paper aims to provide an understanding of this shift. I show that the Camp Century ice core was at the heart of a complex blend of environmental, military and scientific interests. By deconstructing these interests, I ultimately show that the island of Greenland underwent two reimaginings during the early Cold War. First, the island was reimagined as part of the US Cold War military sphere: driven by the need to secure the North American continent, the US established a hegemonic military colonization of Greenland. In the second reimagining of the island, environmental geography led the way: the scientific results of the Camp Century ice core and political concern about climatic change converged in the early 1970s to build Greenland into a unique location for pursuing research on climate questions. This paper adds to the literature by contextualizing the Camp Century ice core at the interface between the history of science, environmental history and Cold War history, and thereby illuminating Greenland as a dual geopolitical entity and environmental space. By highlighting the interaction of climatic change, geophysical sciences and national security narratives, it responds to recent historiographic calls to unite a set of narratives which, too often, talk past one another.  相似文献   

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Following demands to regulate biomedicine in the post-war period, Sweden saw several political debates about research ethics in the 1970s. Many of the debates centered on fetal research and animal experiments. At stake were questions of moral permissibility, public transparency, and scientific freedom. However, these debates did not only reveal ethical disagreement—they also contributed to constructing new boundaries between life-forms. Taking a post-Marxist approach to discursive policy analysis, we argue that the meaning of both the “human” and the “animal” in these debates was shaped by a need to manage a legitimacy crisis for medical science. By analyzing Swedish government bills, motions, parliamentary debates, and committee memorials from the 1970s, we map out how fetal and animal research were constituted as policy problems. We place particular emphasis on the problematization of fetal and animal vulnerability. By comparing the debates, we trace out how a particular vision of the ideal life defined the human-animal distinction.  相似文献   

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Vascular endothelial growth factors (VEGFs), initially thought to act specifically on the vascular system, exert trophic effects on neural cells during development and adulthood. Therefore, the VEGF system serves as a promising therapeutic target for brain pathologies, but its simultaneous action on vascular cells paves the way for harmful side effects. To circumvent these deleterious effects, many studies have aimed to clarify whether VEGFs directly affect neural cells or if the effects are mediated secondarily via other cell types, like vascular cells. A great number of reports have shown the expression and function of VEGF receptors (VEGFRs), mainly VEGFR-1 and -2, in neural cells, where VEGFR-2 has been described as the major mediator of VEGF-A signals. This review aims to summarize and compare the divergent roles of VEGFR-1 and -2 during CNS development and homeostasis.  相似文献   

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Tautomerase superfamily members have an amino-terminal proline and a β–α–β fold, and include 4-oxalocrotonate tautomerase (4-OT), 5-(carboxymethyl)-2-hydroxymuconate isomerase (CHMI), trans- and cis-3-chloroacrylic acid dehalogenase (CaaD and cis-CaaD, respectively), malonate semialdehyde decarboxylase (MSAD), and macrophage migration inhibitory factor (MIF), which exhibits a phenylpyruvate tautomerase (PPT) activity. Pro-1 is a base (4-OT, CHMI, the PPT activity of MIF) or an acid (CaaD, cis-CaaD, MSAD). Components of the catalytic machinery have been identified and mechanistic hypotheses formulated. Characterization of new homologues shows that these mechanisms are incomplete. 4-OT, CaaD, cis-CaaD, and MSAD also have promiscuous activities with a hydratase activity in CaaD, cis-CaaD, and MSAD, PPT activity in CaaD and cis-CaaD, and CaaD and cis-CaaD activities in 4-OT. The shared promiscuous activities provide evidence for divergent evolution from a common ancestor, give hints about mechanistic relationships, and implicate catalytic promiscuity in the emergence of new enzymes. Received 22 May 2008; received after revision 20 June 2008; accepted 02 July 2008  相似文献   

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It is widely acknowledged that the patient's perspective should be considered when making decisions about how her care will be managed. Patient participation in the decision making process may play an important role in bringing to light and incorporating her perspective. The GRADE framework is touted as an evidence-based process for determining recommendations for clinical practice; i.e. determining how care ought to be managed. GRADE recommendations are categorized as “strong” or “weak” based on several factors, including the “values and preferences” of a “typical” patient. The strength of the recommendation also provides instruction to the clinician about when and how patients should participate in the clinical encounter, and thus whether an individual patient's values and preferences will be heard in her clinical encounter. That is, a “strong” recommendation encourages “paternalism” and a “weak” recommendation encourages shared decision making. We argue that adoption of the GRADE framework is problematic to patient participation and may result in care that is not respectful of the individual patient's values and preferences. We argue that the root of the problem is the conception of “values and preferences” in GRADE – the framework favours population thinking (e.g. “typical” patient “values and preferences”), despite the fact that “values and preferences” are individual in the sense that they are deeply personal. We also show that tying the strength of a recommendation to a model of decision making (paternalism or shared decision making) constrains patient participation and is not justified (theoretically and/or empirically) in the GRADE literature.  相似文献   

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The faculty of economics at today's Humboldt University in Berlin, as no other institution of economics, has witnessed three radical ruptures in its history: in 1933, National Socialism replaced the pluralism prevailing in the Weimar Republic by imposing a “German economics”; after WWII, GDR authorities replaced this NS regime by imposing a Marxist imperative, which after the fall of the wall was replaced by the Western standards of neoclassical economics. In reconstructing these three reforms, institutional history can serve as a context in which questions about the political nature of economic knowledge can be answered that remain speculative in a conceptual context. I thus present a natural experiment in the political epistemology of economics: How do economists respond to, resist, and stabilize, changing political regimes? How do economists renegotiate the autonomy of economic knowledge given changing demands as of its social task? Among others, I show that contrary to Robert Merton's old, but still widely held thesis in political epistemology—that the values of science are compatible only with democratic regimes—the totalitarian and authoritarian regimes created better conditions for methodological pluralism in economics than democratic society.  相似文献   

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