7,761 research outputs found

    Information economics as mainstream economics and the limits of reform: what does the Stiglitz Report and its aftermath tell us?

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    In this paper we use the Stiglitz Report of 2009/2011 as a point of departure to explore the way the development in economics theory provides a limited contribution to further reform. In so doing we provide a detailed analysis of potential underlying problems of information-theoretic economics. We note this provides an additional way to consider Thomas Palley’s concept of Gattopardo economics

    Marxism and science studies: a sweep through the decades

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    This paper outlines the distinctive contribution of marxism to science studies. It traces the trajectory of marxist ideas through the decades from the origins of marxism to the present conjuncture. It looks at certain key episodes, such as the arrival of a Soviet delegation at the International History of Science Congress in London in 1931 as well as subsequent interactions between marxists and exponents of other positions at later international congresses. It focuses on the impact of several generations of marxists who have engaged with science in different ways. It examines the influence of marxism on contemporary trends in science studies. It concludes that marxism survives in circuitous and complex ways. It argues not only for a positive interpretation of its contribution in the past but for its explanatory and ethical power in the present and future

    J D Bernal: philosophy, politics and the science of science

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    This paper is an examination of the philosophical and political legacy of John Desmond Bernal. It addresses the evidence of an emerging consensus on Bernal based on the recent biography of Bernal by Andrew Brown and the reviews it has received. It takes issue with this view of Bernal, which tends to be admiring of his scientific contribution, bemused by his sexuality, condescending to his philosophy and hostile to his politics. This article is a critical defence of his philosophical and political position

    J D Bernal: philosophy, politics and the science of science

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    This paper is an examination of the philosophical and political legacy of John Desmond Bernal. It addresses the evidence of an emerging consensus on Bernal based on the recent biography of Bernal by Andrew Brown and the reviews it has received. It takes issue with this view of Bernal, which tends to be admiring of his scientific contribution, bemused by his sexuality, condescending to his philosophy and hostile to his politics. This article is a critical defence of his philosophical and political position

    Pathway of protection: Ethnic identity, self-esteem, and substance use among multiracial youth

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    Fifty percent of adolescents have tried an illicit drug and 70% have tried alcohol by the end of high school, with even higher rates among multiracial youth. Ethnic identity is a protective factor against substance use for minority groups. However, little is known about the mechanisms that facilitate its protective effects, and even less is known about this relationship for multiracial youth. The purpose of the present study was to examine the protective effect of ethnic identity on substance use and to determine whether this relationship operated indirectly through self-esteem, a strong predictor of substance use for among adolescent populations. Participants included 468 multiracial youth in grades six through 12 (53% female). The results found that ethnic identity was indeed related to substance use, partially through changes in self-esteem. Findings from this study contribute to our understanding and development of models of risk and protection for an understudied population

    Acetylcholinesterase activity measurement and clinical features of delirium

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    Aims: Cholinergic deficiency is commonly implicated in the pathophysiology of delirium. We aimed to investigate the relationship between directly measured serum AChE activity and (1) clinical features of delirium and (2) outcomes, among older hospital patients with delirium. Methods: Hospitalized patients with delirium were recruited and delirium motor subtype, severity and duration of delirium were measured. Serum AChE activity was measured using a colorimetric assay. Results: The mean AChE activity for the whole sample was 2.46 μmol/μml/min (SD 1.75). Higher AChE activity was associated with increased likelihood of hypoactive delirium rather than the hyperactive or mixed subtype (OR 1.98, CI 1.10-3.59). Conclusion: Higher AChE activity was associated with hypoactive delirium, but did not predict outcomes. Simple enhancement of cholinergic neurotransmission may not be sufficient to treat deliriu

    Maximal work extraction from quantum systems

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    Thermodynamics teaches that if a system initially off-equilibrium is coupled to work sources, the maximum work that it may yield is governed by its energy and entropy. For finite systems this bound is usually not reachable. The maximum extractable work compatible with quantum mechanics (``ergotropy'') is derived and expressed in terms of the density matrix and the Hamiltonian. It is related to the property of majorization: more major states can provide more work. Scenarios of work extraction that contrast the thermodynamic intuition are discussed, e.g. a state with larger entropy than another may produce more work, while correlations may increase or reduce the ergotropy.Comment: 5 pages, 0 figures, revtex

    Computational Studies of Magnetic Nozzle Performance

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    An extensive literature review of magnetic nozzle research has been performed, examining previous work, as well as a review of fundamental principles. This has allow us to catalog all basic physical mechanisms which we believe underlie the thrust generation process. Energy conversion mechanisms include the approximate conservation of the magnetic moment adiabatic invariant, generalized hall and thermoelectric acceleration, swirl acceleration, thermal energy transformation into directed kinetic energy, and Joule heating. Momentum transfer results from the interaction of the applied magnetic field with currents induced in the plasma plume., while plasma detachment mechanisms include resistive diffusion, recombination and charge exchange collisions, magnetic reconnection, loss of adiabaticity, inertial forces, current closure, and self-field detachment. We have performed a preliminary study of Hall effects on magnetic nozzle jets with weak guiding magnetic fields and weak expansions (p(sub jet) approx. = P(sub background)). The conclusion from this study is that the Hall effect creates an azimuthal rotation of the plasma jet and, more generally, creates helical structures in the induced current, velocity field, and magnetic fields. We have studied plasma jet expansion to near vacuum without a guiding magnetic field, and are presently including a guiding magnetic field using a resistive MHD solver. This research is progressing toward the implementation of a full generalized Ohm's law solver. In our paper, we will summarize the basic principle, as well as the literature survey and briefly review our previous results. Our most recent results at the time of submittal will also be included. Efforts are currently underway to construct an experiment at the University of Michigan Plasmadynamics and Electric Propulsion Laboratory (PEPL) to study magnetic nozzle physics for a RF-thruster. Our computational study will work directly with this experiment to validate the numerical model, in order to study magnetic nozzle physics and optimize magnetic nozzle design. Preliminary results from the PEPL experiment will also be presented
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