10,949 research outputs found

    Mean-Field Spin Glass models from the Cavity--ROSt Perspective

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    The Sherrington-Kirkpatrick spin glass model has been studied as a source of insight into the statistical mechanics of systems with highly diversified collections of competing low energy states. The goal of this summary is to present some of the ideas which have emerged in the mathematical study of its free energy. In particular, we highlight the perspective of the cavity dynamics, and the related variational principle. These are expressed in terms of Random Overlap Structures (ROSt), which are used to describe the possible states of the reservoir in the cavity step. The Parisi solution is presented as reflecting the ansatz that it suffices to restrict the variation to hierarchal structures which are discussed here in some detail. While the Parisi solution was proven to be correct, through recent works of F. Guerra and M. Talagrand, the reasons for the effectiveness of the Parisi ansatz still remain to be elucidated. We question whether this could be related to the quasi-stationarity of the special subclass of ROSts given by Ruelle's hierarchal `random probability cascades' (also known as GREM).Comment: Based on talks given at `Young Res. Symp.', Lisbon 2003, and `Math. Phys. of Spin Glasses', Cortona 200

    Purposive discovery of operations

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    The Generate, Prune & Prove (GPP) methodology for discovering definitions of mathematical operators is introduced. GPP is a task within the IL exploration discovery system. We developed GPP for use in the discovery of mathematical operators with a wider class of representations than was possible with the previous methods by Lenat and by Shen. GPP utilizes the purpose for which an operator is created to prune the possible definitions. The relevant search spaces are immense and there exists insufficient information for a complete evaluation of the purpose constraint, so it is necessary to perform a partial evaluation of the purpose (i.e., pruning) constraint. The constraint is first transformed so that it is operational with respect to the partial information, and then it is applied to examples in order to test the generated candidates for an operator's definition. In the GPP process, once a candidate definition survives this empirical prune, it is passed on to a theorem prover for formal verification. We describe the application of this methodology to the (re)discovery of the definition of multiplication for Conway numbers, a discovery which is difficult for human mathematicians. We successfully model this discovery process utilizing information which was reasonably available at the time of Conway's original discovery. As part of this discovery process, we reduce the size of the search space from a computationally intractable size to 3468 elements

    Organochloride Pesticides Present in Animal Fur, Soil, and Streambed in an Agricultural Region of Southeastern Arkansas

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    Animals in agricultural settings may be subject to bioaccumulation of toxins. For the last several years, we collected hair samples from bats and rodents in an agricultural area near Bayou Bartholomew in Drew County, Arkansas. Samples were submitted to the Center of Environmental Sciences and Engineering at the University of Connecticut for wide-screen toxin analysis. Several of these samples contained measurable amounts of organochloride pesticides or their metabolites, including some that have been banned for decades, such as dichlorodiphenyltrichloroethane (DDT) and chlordane. In addition, we collected several samples of soil from within an agricultural field, from adjacent edge habitat, from alongside the bank of the Bayou, and from the bed of the Bayou itself. Although none of these samples tested positive for DDT or chlordane, all of the samples except one contained measurable amounts of metabolites from these pesticides. This study raises questions about environmental persistence of DDT/DDE and other organochlorides. There may be risk to wildlife populations, warranting further investigation into effects of long-term exposure to these toxins

    Thermal acoustic oscillations, volume 2

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    A number of thermal acoustic oscillation phenomena and their effects on cryogenic systems were studied. The conditions which cause or suppress oscillations, the frequency, amplitude and intensity of oscillations when they exist, and the heat loss they induce are discussed. Methods of numerical analysis utilizing the digital computer were developed for use in cryogenic systems design. In addition, an experimental verification program was conducted to study oscillation wave characteristics and boiloff rate. The data were then reduced and compared with the analytical predictions

    Educational Needs and Opportunities for Personnel in Convention and Visitor Bureaus

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    This study was undertaken to examine skills and personal qualities which are desirable for employment in convention and visitor bureaus and to identify employment opportunities. Despite a small return, it was found that there were employment opportunities available in CVB\u27s. Sales level {professional) career opportunities were the most frequently reported openings within the responding bureaus. Important skills and personal qualities for all employment levels were identified. Desirable degree areas and years of experience desired were also identified. Professional associations were found to be the primary source of training opportunities. University education and training offerings were geared to the matriculated student, and not easily accessible to professionals already employed in a CVB. There is a need for universities to work closer with the professional associations to develop and provide education and training opportunities for individuals interested in careers in convention and visitor bureaus

    Developing a Fertilizer Program for Tobacco

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    Use of adequate amounts of required fertilizer nutrients are necessary to increase both yield and quality of tobacco if they are lacking in a soil. However, to insure maximum profits from the tobacco crop, careful consideration must be given to fertilizer management (kinds, rates, and methods and times of fertilizer application), the chemical and physical characteristics of the soil, and the crops grown in rotation with tobacco. To develop a profitable fertilization program for tobacco requires thoughtful planning on the part of the grower. Late summer and early fall is a good time to make these plans for the future

    Impacts of mindfulness on disruptive behaviors associated with characteristics of ADHD

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    The prevalence of ADHD has drastically increased over the last decade, and children with this disorder often receive attention from their teachers for their disruptive behaviors (Visser, Danielson, Bitsko, Holbrook, Kogan, Ghandour,... & Blumberg, 2014). Students with ADHD often struggle with controlling their impulses that lead to these disruptions in the classroom. If not addressed, the classroom learning environment is likely to be negatively impacted (Lambert, Cartledge, Heward, & Lo, 2006). Introducing students with ADHD to the practice of mindfulness may help to create a space, or a delay in responding, between thoughts and actions which may, in turn, reduce the amount of disruptive behaviors teachers must manage in the classroom. The following literature will describe mindfulness and its implementation in the K-12 setting; and then, describe ADHD symptoms and how mindfulness is used to address these symptoms
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