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The term stimulus, as it was used in science from its earliest appearance in the sixteenth century up to the beginning of the nineteenth century, shows a gradual progress in denotation from the physical object designed to produce nervous and muscular excitation to the generically conceived event or object that initiates sensory or motor activity. To this shift corresponds a shift in the understanding of sensory experience. Johannes Müller's law of specific energy of sensory nerves played a major role in the shift, and Hermann von Helmholtz gave the shift its most thorough philosophical explanation.  相似文献   
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Mumba Rockshelter, Tanzania, is the only East African site spanning a continuous record of more than 100,000 years, including the Middle Stone Age (MSA) to Late Stone Age (LSA) Transition. Rather than examine the presence or absence of traditional markers of “behavioral modernity”, we have endeavored here to respond to the calls of Shea (2011) and Basell (2008) by examining the proportional similarity of a trait present throughout the MSA–LSA sequence at Mumba Rockshelter: the bipolar technique of lithic reduction. We use a quantified, experimentally derived proxy to track the relative amount of bipolar percussion among Mumba's Beds VI, V, and III, namely, waste shatter. Our examination of Mehlman's previously unanalyzed collections from Mumba demonstrates that in terms of bipolar production Bed V is statistically indistinguishable from the Late Stone Age (LSA) Bed III, but significantly different from the Middle Stone Age (MSA) Bed VI. Given that Bed V dates to 56.9 ± 4.8 − 49.1 ± 4.3 ka cal BP, this result is consistent with other evidence that the origins of the LSA in East Africa began well before 40 kya, and that Mumba Bed V represents one of the earliest manifestations of the LSA in East Africa. We conclude with a discussion of factors that may have influenced the increased dependence of bipolar production at the site.  相似文献   
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In this paper, the damage potential of an earthquake ground motion is evaluated in terms of the total power of the acceleration of the ground motion. By assuming an appropriate spectral shape for the input energy spectrum, and using the well-known Parseval theorem for evaluating the total power of a random signal, the peak amplification factor for the equivalent input energy velocity spectrum can be determined. It is shown that the peak amplification factor for the input energy spectrum depends on the peak-ground-acceleration to peak-ground-velocity ratio and duration of the strong motion phase of the ground motion. Values for the equivalent input energy velocity amplification factor vary from about 2 to 10 for most of the recorded ground motions used in this study. Although a considerable scatter of data is observed in this study, the peak amplification factor predicted by the Fourier amplitude spectrum of the ground acceleration provides a fairly good estimate of the mean value of the peak input energy compared to that determined from inelastic dynamic time history analyses, particularly for systems with high damping and low lateral strength. The peak amplification factor derived in this paper provides a more consistent approach for estimation of seismic demand when compared to an earlier empirical expression used for the formulation of duration-dependent inelastic seismic design spectra, even though only a slight difference in the required lateral strength results from the use of the new formula.  相似文献   
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In this paper, the damage prediction of shear-dominated reinforced concrete (RC) elements subjected to reversed cyclic shear is presented using an existing damage model. The damage model is primarily based on the monotonic energy dissipating capacity of structural elements before and after the application of reversed cyclic loading. Therefore, it could be universally applicable to different types of structural members, includeing shear-dominated RC members. The applicability of the damage model to shear-dominated RC members is assessed using the results from reversed cyclic shear load tests conducted earlier on eleven RC panels. First, the monotonic energy dissipating capacities of the panels before and after the application of reversed cyclic loading are estimated and employed in the damage model. Next, a detailed comparison between the analytically predicted damage and the observed damage from the experimental tests of the panels is performed throughout the loading history. Subsequently, the effects of two important parameters, the orientation and the percentage of reinforcement, on the damage of such shear-dominated panels are studied. The research results demonstrated that the analytically predicted damage is in reasonably good agreement with the observed damage throughout the entire loading history. Furthermore, the orientation and percentage of reinforcement is found to have considerable effect on the extent of damage.  相似文献   
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A significant proportion of the Paris metro tunnels comprise a masonry vault built out of stone blocks and mortar joints, and sidewalls and slabs made of unreinforced concrete. In order to provide the necessary data for future structural evaluation, an extensive laboratory testing programme has been conducted to characterize the materials of the tunnel separately, i.e., mortar, stone, and concrete. The tests, carried out on specimens taken from cores extracted from a 1930s tunnel, enabled to determine the mechanical properties, including direct tensile, shear strength, and mode I fracture energy, as well as the properties of the stone-mortar interface. Results show that the masonry mortar joints could reach 10 cm in width, and that blocks of stone varied in composition and porosity, thus producing a wide range of mechanical properties. The concrete was composed of large-sized aggregates and showed low stiffness and strength. Based on these experimental results, ratios between mechanical characteristics are hereby proposed. Perspectives on the use of this experimental data in a finite element model are then discussed.  相似文献   
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This article examines an often overlooked but nevertheless important element of Canada’s Cold War-era development assistance policies—the export of nuclear reactors to the developing world. In particular, the focus is on societal responses to India’s explosion of an underground nuclear device in May 1974, an accomplishment made possible in part through the export of Canada’s nuclear expertise, technology, and material. India’s entrance into the nuclear club sparked an intense and wide-ranging debate in Canadian society concerning the nature of Canada’s development and foreign policies, and more specifically, the types of policies that would enable the country to fulfill its main international purpose as a middle power—contributing to conditions of international peace and security. The protracted debate which involved not only politicians but many civil society actors revealed stark divisions among Canadians centered on the extent to which nuclear reactor exports served Canadian national interests.  相似文献   
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This paper seeks to make a contribution to on-going debates about how to conceptualise the spatial processes of renewable energy transition. It makes a case for understanding renewable energy transitions as simultaneously spatial and political processes, constitutive of new territories and configuring development pathways. Drawing on a case study of South Africa's Renewable Energy Independent Power Procurement Programme (REI4P), the paper explores the ways in which energy transitions are intrinsically bound up with both the materiality and the historical and contemporary politics of land. It then examines the relationship between energy transitions and territory to conceptualise the ways in which transitions take on an experimental shape in the form of 'zones'. The paper argues that these zones are new territories deploying forms of spatial and political-administrative exceptionality, which allow political and economic actors to exercise authority and commercial power. Two types of zone emerging from South Africa's energy transition exemplify these processes: legally-defined zones for the development of solar and wind energy and zones of socioeconomic development required by REI4P. The paper explores the spatial and political consequences of these strategies and suggests that these may not necessarily translate into conflict and confrontation, but instead produce uneasy co-existences of different political, social and spatial projects and interests, with potential to create new polities.  相似文献   
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Human-induced global threats are compelling many anthropologists to rethink roles, methods, and paradigms and engage in public debate and action on energy policies, extraction processes, commodity chains, and consumption. Laura Nader's Energy Reader embodies her decades-long engagement as a catalyst for public debate on U.S. energy issues. Tanja Winther's Impact of Electricity exemplifies ethnography informing development practice. Strauss and colleagues’ Cultures of Energy reflects diverse approaches seeking to build cultural understandings to inform energy choices. There remains a need for collaboration with anthropologists embedded in energy-related agencies—positioned where they can leverage anthropological knowledge to push policy envelopes.  相似文献   
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