4,934 research outputs found

    Entropy in the Kerr-Newman Black Hole

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    Entropy of the Kerr-Newman black hole is calculated via the brick wall method with maintaining careful attention to the contribution of superradiant scalar modes. It turns out that the nonsuperradinat and superradiant modes simultaneously contribute to the entropy with the same order in terms of the brick wall cutoff ϵ\epsilon. In particular, the contribution of the superradiant modes to the entropy is negative. To avoid divergency in this method when the angular velocity tends to zero, we propose to intr oduce a lower bound of angular velocity and to treat the case of the angular momentum per unit mass a=0a=0 separately. Moreover, from the lower bound of the angular velocity, we obtain the θ\theta-dependence structure of the brick wall cutoff, which natu rally requires an angular cutoff δ\delta. Finally, if the cutoff values, ϵ\epsilon and δ\delta, satisfy a proper relation between them, the resulting entropy satisfies the area law.Comment: 16 pages, Latex, no figures, References are included, Subsection A and B are reduced to subsection A, Abstract is rewritten, Minor corrections are include

    ELECTROMYOGRAPHICAL ANALYSIS OF TRUNK MUSCLE ACTIVITIES DURING A GOLF SWING

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    The purposes of this study were to describe and compare the activation patterns of the trunk muscles during a golf swing using surface electromyographic (EMG) techniques. Five male collegiate golfers were the subjects. The golf swing was broken into five phases using the critical instants identified from video recordings. Wilcoxon signed ranks tests were used to test for significant differences (12 < .05) in average and peak normalized EMG values between the left and right muscles for each phase. The significant bilateral differences in muscle activation were only found in the average and peak rectus abdominus (acceleration phase), external oblique (acceleration and early follow-through phases), and erector spinae (late follow-through phase). The trunk muscles were highly active in the follow-through phases which may indicate the hyperextension of the trunk, which leads to lower back injury

    Rheological method for alpha test evaluation of developing superplasticizers&apos; performance: Channel flow test

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    Advance in high-range water-reducing admixture revolutionizes the workability and constructability of conventional vibrated concrete as well as self-consolidating concrete. Its need from construction fields has increased, and consequently a variety of new-type polycarboxylates, base polymers for the admixture, are being formulated in these days. Synthesizing new polymers needs a quick, but reliable, test to evaluate its performance on concrete. The test is also asked for selecting the best applicable brand of them before a test concrete will be mixed. This paper proposes a channel flow test and its usage for the purpose. The proposed procedure for the test includes the mix proportion of a test mortar, the test method, and rheological interpretation of the test results.ope

    Preparation of polylactide-co-glycolide nanoparticles incorporating celecoxib and their antitumor activity against brain tumor cells

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    Tae-Ho Kim1*, Young-Il Jeong2*, Shu-Guang Jin2, Jian Pei2, Tae-Young Jung1, Kyung-Sub Moon1, In-Young Kim1, Sam-Suk Kang1, Shin Jung1,21Department of Neurosurgery, 2Brain Tumor Research Laboratory, Chonnam National University Research Institute of Medical Science, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Republic of Korea *These authors contributed equally to this work. Background: Celecoxib, a cyclo-oxygenase (COX)-2 inhibitor, has been reported to mediate growth inhibitory effects and to induce apoptosis in various cancer cell lines. In this study, we examined the potential effects of celecoxib on glioma cell proliferation, migration, and inhibition of COX-2 expression in vitro. Methods: Celecoxib was incorporated into poly DL-lactide-co-glycolide (PLGA) nanoparticles for antitumor drug delivery. Results: PLGA nanoparticles incorporating celecoxib had spherical shapes and their particle sizes were in the range of 50&amp;ndash;200 nm. Drug-loading efficiency was not significantly changed according to the solvent used, except for acetone. Celecoxib was released from the PLGA nanoparticles for more than 2 days, and the higher the drug content, the longer the duration of drug release. PLGA nanoparticles incorporating celecoxib showed cytotoxicity against U87MG tumor cells similar to that of celecoxib administered alone. Furthermore, celecoxib did not affect the degree of migration of U87MG cells. PLGA nanoparticles incorporating celecoxib showed dose-dependent cytotoxicity similar to that of celecoxib alone in C6 rat glioma cells. Western blot assay of the C6 cells showed that neither celecoxib alone nor PLGA nanoparticles incorporating celecoxib affected COX-2 expression. Conclusion: PLGA nanoparticles incorporating celecoxib had antitumor activity similar to that of celecoxib alone, even though these particles did not affect the degree of migration or COX-2 expression in the tumor cells. Keywords: celecoxib, cyclo-oxygenase-2, PLGA nanoparticles, glioma, antitumor activit

    EvalLM: Interactive Evaluation of Large Language Model Prompts on User-Defined Criteria

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    By simply composing prompts, developers can prototype novel generative applications with Large Language Models (LLMs). To refine prototypes into products, however, developers must iteratively revise prompts by evaluating outputs to diagnose weaknesses. Formative interviews (N=8) revealed that developers invest significant effort in manually evaluating outputs as they assess context-specific and subjective criteria. We present EvalLM, an interactive system for iteratively refining prompts by evaluating multiple outputs on user-defined criteria. By describing criteria in natural language, users can employ the system's LLM-based evaluator to get an overview of where prompts excel or fail, and improve these based on the evaluator's feedback. A comparative study (N=12) showed that EvalLM, when compared to manual evaluation, helped participants compose more diverse criteria, examine twice as many outputs, and reach satisfactory prompts with 59% fewer revisions. Beyond prompts, our work can be extended to augment model evaluation and alignment in specific application contexts
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