802 research outputs found

    Quantum Uncertainty, Quantum Play, Quantum Sorrow

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    I argue that intrinsic (as opposed to epistemic or Einsteinian) quantum uncertainty informs the elemental life experiences of random play and compassionate sorrow. These experiences, like Niels Bohr's quantum ontology, point toward unscripted novelty, fresh variation, and far-flung sympathetic interconnections. And in doing this, they allow the inner and outer feeling experiences to grow back together. As we feel the world sensibly”that is, touch it with our sense organs”it touches back in a way that engenders feeling-laden or sympathetic understanding

    Comminution Studies

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    Comminution, reduction in size, is one of the most important, yet least understood, steps in mineral dressing. So that more efficient comminuting devices may be designed and constructed, a better knowledge of the relationship between energy consumption and size reduction is desired. Occasional studies during the last 100 years have produced a few laws purporting to describe this relationship. In each case, the promulgators and supporters of these laws have presented experimental evidence for their verification. Obviously, all of these advocated practices cannot be correct. To the mill designer, the problem is Which, if any, of these laws are valid. In an effort to answer the above question, this investigation was undertaken to study and evaluate the best-known relationships

    Conceptual Nonlocality

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    Nonlocality is a puzzling issue in modern physics. I propose that, aside from the experimental determination of nonlocality, the concept of atomistic lightmdash;discrete, self-bounded photonsmdash;breaks down toward something like nonlocality when subjected to philosophical scrutiny. Louis de Broglie made a similar argument regarding the material atom: the concept of the classical atom, when interrogated, collapses upon itself to offer a glimpse of wave-particle duality. Light atoms or photons, I argue, similarly collapse toward the contradictory possibility of nonlocality

    Failure of Intravenous Morphine to Serve as an Effective Instrumental Reinforcer in Dopamine D2 Receptor Knock-Out Mice

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    The rewarding effects of opiates are thought to be mediated through dopaminergic mechanisms in the ventral tegmental area, dopamine-independent mechanisms in the nucleus accumbens, or both. The purpose of the present study was to explore the contribution of dopamine to opiate-reinforced behavior using D2 receptor knock-out mice. Wild-type, heterozygous, and D2 knock-out mice were first trained to lever press for water reinforcement and then implanted with intravenous catheters. The ability of intravenously delivered morphine to maintain lever pressing in these mice was studied under two schedules of reinforcement: a fixed ratio 4 (FR4) schedule (saline, 0.1, 0.3, or 1.0 mg/kg, per injection) and a progressive ratio (PR) schedule (1.0 mg/kg, per injection). In the wild-type and heterozygous mice, FR4 behavior maintained by morphine injections was significantly greater than behavior maintained by vehicle injections. Response rate was inversely related to injection dose and increased significantly in the wild-type and heterozygous mice when the animals were placed on the PR schedule. In contrast, the knock-out mice did not respond more for morphine than for saline and did not respond more when increased ratios were required by the PR schedule. Thus, morphine served as a positive reinforcer in the wild-type and heterozygous mice but failed to do so in the knock-out mice. Under this range of doses and response requirements, the rewarding effects of morphine appear to depend critically on an intact D2 receptor systemFil: Elmer, Greg I.. University of Maryland; Estados UnidosFil: Pieper, Jeanne O.. National Institutes of Health; Estados UnidosFil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Low, Malcolm J.. Oregon Health and Sciences University; Estados UnidosFil: Grandy, David K.. Oregon Health and Sciences University; Estados UnidosFil: Wise, Roy A.. National Institutes of Health; Estados Unido

    Saving our soils

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    Strength and Conditioning Coaches\u27 Perceptions of Sport Psychology Strategies

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    Strength and conditioning coaches (SCCs) hold a central role in the development of student-athletes. Although they certainly focus on student-athletes\u27 physical skill development, SCCs are in an ideal position to integrate mental skills into their strength and conditioning sessions. For example, sport psychology (SP) strategies can be used within strength and conditioning sessions to assist in athlete exercise execution by regulating arousal, improving concentration, confidence, as well as improve self-correction through self-talk and imagery. The purpose of this study was to assess collegiate SCCs\u27 use of SP skills/strategies. A total sample of 415 SCCs (19.7% return rate) across the United States participated in an online survey. Although the majority of these coaches reported having less than moderate training in SP (59.9%), they also reported a moderate to high use of certain SP strategies (e.g., goal setting, self-talk). Strength and conditioning coaches\u27 familiarity with, knowledge of, and confidence to use the SP strategies were found to be predictors of SCCs\u27 frequency of SP strategy use. This study aimed to provide an initial exploration of SCCs\u27 understanding and use of specific SP strategies, which was influenced by the SCCs\u27 perceived level of preparation to use these strategies. For SCCs to be able to purposefully and confidently incorporate SP strategies into training sessions, the current study suggests the need for specific training aimed to enhance the SCCs\u27 knowledge of and confidence in using specific SP strategies

    Changes in substrate availability drive carbon cycle response to chronic warming

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    As earth\u27s climate continues to warm, it is important to understand how the capacity of terrestrial ecosystems to retain carbon (C) will be affected. We combined measurements of microbial activity with the concentration, quality, and physical accessibility of soil carbon to microorganisms to evaluate the mechanisms by which more than two decades of experimental warming has altered the carbon cycle in a Northeast US temperate deciduous forest. We found that concentrations of soil organic matter were reduced in both the organic and mineral soil horizons. The molecular composition of the carbon was altered in the mineral soil with significant reductions in the relative abundance of polysaccharides and lignin, and an increase in lipids. Mineral-associated organic matter was preferentially depleted by warming in the top 3 cm of mineral soil. We found that potential extracellularenzyme activity per gram of soil at a common temperature was generally unaffected by warming treatment. However, by measuring potential extracellular enzyme activities between 4 and 30 °C, we found that activity per unit microbial biomass at in-situ temperatures was increased by warming. This was associated with a tendency for microbial biomass to decrease with warming. These results indicate that chronic warming has reduced soil organic matter concentrations, selecting for a smaller but more active microbial community increasingly dependent on mineral-associated organic matter

    The statistical mechanics of networks

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    We study the family of network models derived by requiring the expected properties of a graph ensemble to match a given set of measurements of a real-world network, while maximizing the entropy of the ensemble. Models of this type play the same role in the study of networks as is played by the Boltzmann distribution in classical statistical mechanics; they offer the best prediction of network properties subject to the constraints imposed by a given set of observations. We give exact solutions of models within this class that incorporate arbitrary degree distributions and arbitrary but independent edge probabilities. We also discuss some more complex examples with correlated edges that can be solved approximately or exactly by adapting various familiar methods, including mean-field theory, perturbation theory, and saddle-point expansions.Comment: 15 pages, 4 figure

    Lattice Calculation of Point-to-Point Hadron Current Correlation

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    Point-to-point correlation functions of hadron currents in the QCD vacuum are calculated on a lattice and analyzed using dispersion relations, providing physical information down to small spatial separations. Qualitative agreement with phenomenological results is obtained in channels for which experimental data are available, and these correlation functions are shown to be useful in exploring approximations based on sum rules and interacting instantons.Comment: 11 page
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