3,389 research outputs found

    Birefringent Electroweak Textures

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    The behaviour of electromagnetic waves propagating through an electroweak homilia string network is examined. This string network is topologically stable as a cosmic texture, and is characterized by the spatial variation of the isospin rotation of the Higgs field. As a consequence the photon field couples to the intermediate vector bosons, producing a finite range electromagnetic field. It is found that the propagation speed of the photon depends on its polarization vector, whence an homilia string network acts as a birefringent medium. We estimate the birefringent scale for this texture and show that it depends on the frequency of the electromagnetic wave and the length scale of the homilia string network.Comment: 10 page

    Validation of the Boston University short form speech sound discrimination test.

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    Thesis (M.A.)--Boston Universit

    A spectral nudging method for the ACCESS1.3 atmospheric model

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    A convolution-based method of spectral nudging of atmospheric fields is developed in the Australian Community Climate and Earth Systems Simulator (ACCESS) version 1.3 which uses the UK Met Office Unified Model version 7.3 as its atmospheric component. The use of convolutions allow for flexibility in application to different atmospheric grids. An approximation using one-dimensional convolutions is applied, improving the time taken by the nudging scheme by 10–30 times compared with a version using a two-dimensional convolution, without measurably degrading its performance. Care needs to be taken in the order of the convolutions and the frequency of nudging to obtain the best outcome. The spectral nudging scheme is benchmarked against a Newtonian relaxation method, nudging winds and air temperature towards ERA-Interim reanalyses. We find that the convolution approach can produce results that are competitive with Newtonian relaxation in both the effectiveness and efficiency of the scheme, while giving the added flexibility of choosing which length scales to nudge

    Adjuvant interferon in melanoma – a resurrection?

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    Why national health research systems matter

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    Some of the most outstanding problems in Computer Science (e.g. access to heterogeneous information sources, use of different e-commerce standards, ontology translation, etc.) are often approached through the identification of ontology mappings. A manual mapping generation slows down, or even makes unfeasible, the solution of particular cases of the aforementioned problems via ontology mappings. Some algorithms and formal models for partial tasks of automatic generation of mappings have been proposed. However, an integrated system to solve this problem is still missing. In this paper, we present AMON, a platform for automatic ontology mapping generation. First of all, we show the general structure. Then, we describe the current version of the system, including the ontology in which it is based, the similarity measures that it uses, the access to external sources, etc

    Method and apparatus for power plant simulation and optimization

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    A system for simulating and optimizing a powerhouse designed to furnish electrical power to a process plant which incorporates a plurality of units for simulating operation of the individual components of the powerhouse, and for calculating the cost of operation of the system as a whole, including the cost of fuel for the powerhouse components and the cost of purchased power needed to satisfy the power demand of the process plant beyond the capacity of the powerhouse. An adaptive search routine varies all of the operative parameters of the powerhouse, on a random basis, and repeats the simulation in order to identify a combination of parameters which represents a lower cost solution. The range of random variation is reduced, as lower cost solutions are not found within a given number of repetitions, in order to identify a precise convergence on the optimum solution. The procedure may be restarted, and repeated many times, with the range of variation each time initially at maximum, in order to insure the identification of the global optimum

    Impression Formation and Durability in Mediated Communication

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    Using literature from impression formation and social information processing theory, we examine the impact of communication style on impression formation and durability in a mediated environment. We leverage common writing styles found in workplace emails—emoticons, uppercase, lowercase, typographical errors—to examine how message receivers evaluate senders using these styles. Via a lab experiment with 748 subjects, including undergraduate students, graduate students, and working professionals, we found that impressions were associated with writing style beyond the email content. Receivers perceived senders of emails containing emoticons, errors, or written entirely in uppercase or lowercase as less functionally competent. They also perceived senders as less methodologically competent when emails used emoticons and less politically competent when emails were all lowercase or contained errors. They perceived senders using a neutral writing style as less sociable than senders using emoticons. In contrast to impression durability in face-to-face environments, receivers positively revised impressions when senders changed their style to neutral from any of the non-neutral styles. We attribute this difference to two characteristics of the IT artifact: symbol variety and reprocessability

    The effect of soy phytoestrogen supplementation on thyroid status and cardiovascular risk markers in patients with subclinical hypothyroidism: A randomized, double-blind, crossover study

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    Context: There is concern whether soy phytoestrogens may affect thyroid function. If true, soy phytoestrogens may be expected to have a greater impact in subjects with subclinical hypothyroidism. Objective: The primary aim was to determine the effect of soy phytoestrogen supplementation on thyroid function, with a secondary aim of assessing the effects on cardiovascular risk indices in patients with subclinical hypothyroidism. Design and Setting: We conducted a randomized, double-blind, crossover study in a tertiary care setting. Participants: Sixty patients with subclinical hypothyroidism participated in the study. Intervention: Patients were randomly assigned to either low-dose phytoestrogen (30 g soy protein with 2 mg phytoestrogens, representative of a Western diet) or high-dose phytoestrogen (30 g soy protein with 16 mg phytoestrogens, representative of a vegetarian diet) supplementation for 8 wk, then crossed over after an 8-wk washout period. Main Outcome Measures: The primary outcome was progression to overt hypothyroidism, with secondary outcome measures of blood pressure, insulin resistance, lipids, and highly sensitive C-reactive protein (hsCRP). Results: Six female patients in the study progressed into overt hypothyroidism with a standardized rate ratio of 3.6 (95% confidence interval, 1.9, 6.2) after 16-mg phytoestrogen supplementation. Both systolic and diastolic blood pressure decreased with 16 mg phytoestrogens, whereas systolic pressure alone decreased with 2 mg phytoestrogens. Insulin resistance (homeostasis model assessment of insulin resistance, 3.5 ± 0.09 vs. 2.6 ± 0.08; P < 0.02) and hsCRP (4.9 ± 0.04 vs. 3.9 ± 0.03; P < 0.01) decreased with 16 mg phytoestrogens. Lipid profile remained unchanged. Conclusion: There is a 3-fold increased risk of developing overt hypothyroidism with dietary supplementation of 16 mg soy phytoestrogens with subclinical hypothyroidism. However, 16-mg soy phytoestrogen supplementation significantly reduces the insulin resistance, hsCRP, and blood pressure in these patients. Copyright © 2011 by The Endocrine Society
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