789 research outputs found

    Seeing motion and apparent motion

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    In apparent motion experiments, participants are presented with what is in fact a succession of two brief stationary stimuli at two different locations, but they report an impression of movement. Philosophers have recently debated whether apparent motion provides evidence in favour of a particular account of the nature of temporal experience. I argue that the existing discussion in this area is premised on a mistaken view of the phenomenology of apparent motion and, as a result, the space of possible philosophical positions has not yet been fully explored. In particular, I argue that the existence of apparent motion is compatible with an account of the nature of temporal experience that involves a version of direct realism. In doing so, I also argue against two other claims often made about apparent motion, viz. that apparent motion is the psychological phenomenon that underlies motion experience in the cinema, and that apparent motion is subjectively indistinguishable from real motion

    Experimental electronic heat capacities of α\alpha- and δ\delta-Plutonium; heavy-fermion physics in an element

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    We have measured the heat capacities of δ\delta-Pu0.95_{0.95}Al0.05_{0.05} and α\alpha-Pu over the temperature range 2-303 K. The availability of data below 10 K plus an estimate of the phonon contribution to the heat capacity based on recent neutron-scattering experiments on the same sample enable us to make a reliable deduction of the electronic contribution to the heat capacity of δ\delta-Pu0.95_{0.95}Al0.05_{0.05}; we find γ=64±3\gamma = 64 \pm 3 mJK2^{-2}mol1^{-1} as T0T \to 0. This is a factor 4\sim 4 larger than that of any element, and large enough for δ\delta-Pu0.95_{0.95}Al0.05_{0.05} to be classed as a heavy-fermion system. By contrast, γ=17±1\gamma = 17 \pm 1 mJK2^{-2}mol1^{-1} in α\alpha-Pu. Two distinct anomalies are seen in the electronic contribution to the heat capacity of δ\delta-Pu0.95_{0.95}Al0.05_{0.05}, one or both of which may be associated with the formation of the α\alpha'- martensitic phase. We suggest that the large γ\gamma-value of δ\delta-Pu0.95_{0.95}Al0.05_{0.05} may be caused by proximity to a quantum-critical point.Comment: 4 pages, 4 figure

    Functional diversity of chemokines and chemokine receptors in response to viral infection of the central nervous system.

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    Encounters with neurotropic viruses result in varied outcomes ranging from encephalitis, paralytic poliomyelitis or other serious consequences to relatively benign infection. One of the principal factors that control the outcome of infection is the localized tissue response and subsequent immune response directed against the invading toxic agent. It is the role of the immune system to contain and control the spread of virus infection in the central nervous system (CNS), and paradoxically, this response may also be pathologic. Chemokines are potent proinflammatory molecules whose expression within virally infected tissues is often associated with protection and/or pathology which correlates with migration and accumulation of immune cells. Indeed, studies with a neurotropic murine coronavirus, mouse hepatitis virus (MHV), have provided important insight into the functional roles of chemokines and chemokine receptors in participating in various aspects of host defense as well as disease development within the CNS. This chapter will highlight recent discoveries that have provided insight into the diverse biologic roles of chemokines and their receptors in coordinating immune responses following viral infection of the CNS

    University rankings:What do they really show?

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    University rankings as developed by the media are used by many stakeholders in higher education: students looking for university places; academics looking for university jobs; university managers who need to maintain standing in the competitive arena of student recruitment; and governments who want to know that public funds spent on universities are delivering a world class higher education system. Media rankings deliberately draw attention to the performance of each university relative to all others, and as such they are undeniably simple to use and interpret. But one danger is that they are potentially open to manipulation and gaming because many of the measures underlying the rankings are under the control of the institutions themselves. This paper examines media rankings (constructed from an amalgamation of variables representing performance across numerous dimensions) to reveal the problems with using a composite index to reflect overall performance. It ends with a proposal for an alternative methodology which leads to groupings rather than point estimates

    Psychology as a natural science in the eighteenth century

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    Psychology considered as a natural science began as Aristotelian "physics" or "natural philosophy" of the soul. C. Wolff placed psychology under metaphysics, coordinate with cosmology. Scottish thinkers placed it within moral philosophy, but distinguished its "physical" laws from properly moral laws (for guiding conduct). Several Germans sought to establish an autonomous empirical psychology as a branch of natural science. British and French visual theorists developed mathematically precise theories of size and distance perception; they created instruments to test these theories and to measure visual phenomena such as the duration of visual impressions. These investigators typically were dualists who included mental phenomena within nature

    “Influence” In historical explanation: Mary morgan’s traveling facts and the context of influence

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    In my years as a student of Mary Morgan and later as her junior peer, I observed that one concept prompted her to react with caution and skepticism. That common notion was “influence.” In this chapter, I follow her cues to ask what are the legitimate grounds for claims of influence in historical explanation. Morgan’s writings have made us aware that the story of social science cannot be captured in simple reckonings of influence, and that long chains of actions are required to seat an idea in the mind, and longer still to set it to paper. My contribution to problematizing influence is to list the pitfalls of its uncritical use but also, once suitably redefined, its potential contribution to analysis. To illustrate my claims, I propose a test case, to study the “influence of Mary Morgan.
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