5,577 research outputs found

    The centripetal force law and the equation of motion for a particle on a curved hypersurface

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    It is pointed out that the current form of extrinsic equation of motion for a particle constrained to remain on a hypersurface is in fact a half-finished version for it is established without regard to the fact that the particle can never depart from the geodesics on the surface. Once the fact be taken into consideration, the equation takes that same form as that for centripetal force law, provided that the symbols are re-interpreted so that the law is applicable for higher dimensions. The controversial issue of constructing operator forms of these equations is addressed, and our studies show the quantization of constrained system based on the extrinsic equation of motion is favorable.Comment: 5 pages, major revisio

    Heisenberg equation for a nonrelativistic particle on a hypersurface: from the centripetal force to a curvature induced force

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    In classical mechanics, a nonrelativistic particle constrained on an N−1N-1 curved hypersurface embedded in NN flat space experiences the centripetal force only. In quantum mechanics, the situation is totally different for the presence of the geometric potential. We demonstrate that the motion of the quantum particle is "driven" by not only the the centripetal force, but also a curvature induced force proportional to the Laplacian of the mean curvature, which is fundamental in the interface physics, causing curvature driven interface evolution.Comment: 4 page

    Peningkatan Minat Pembelajaran Pendidikan Kewarganegaraan Menggunakan Metode Cerita di Sekolah Dasar

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    : The purpose of this study is to provide information and describe the increased interest in aspects of attention, interest, and willingness of pupils in learning civics using stories in grade 1 Elementary School 04 Sandai. The method used is descriptive method adopted in three cycles, with four stages: planning, action, observation and evaluation of the action, and reflection. Action research in each cycle by performing learning activities through a method of story. From the data obtained there is an increased interest in aspects of attention of the average baseline kesiklus III 36.67% 90.83% difference of 54.2% with a fairly high category, aspects of interest from baseline by an average of 24.2% to the cycle III 82.5% increased by 58.3% with the category is quite high, the willingness aspect of the baseline average of 92.2% increased by 79.2% cycled III by 70% with the higher category

    The Impact of Perceived Lottery Knowledge on Problem Lottery Playing: A Moderated Mediation Model

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    The study explored the mechanism of perceived lottery knowledge in predicting problem in lottery playing through a Moderated Mediation Model centering on overconfidence. A total of 972 Chinese football bettors from nine provinces completed a questionnaire survey. The result showed that: (1) perceived lottery knowledge could positively predict problem lottery playing; (2) perceived lottery knowledge influenced problem lottery playing directly and indirectly through overconfidence; (3) risk perception moderated the mediated path. The indirect effect was stronger for football bettors with low-risk perception than for those with high-risk perception. Implications of consumption and intervention for problem lottery players were discussed.     Keywords: football bettors, problem lottery playing, perceived lottery knowledge, overconfidence, risk perceptio

    Predicted rocket and shuttle effects on stratospheric ozone

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    The major chemical effluents of either solid- or liquid-fueled rockets that can potentially perturb stratospheric ozone include chlorine compounds (HCl), nitrogen compounds (NO(x)), and hydrogen compounds (H2 and H2O). Radicals (Cl, ClO, H, OH, HO2, NO, and NO2) formed directly or indirectly from rocket exhaust can cause the catalytic destruction of ozone. Other exhaust compounds that could presumably lead to ozone destruction either by direct reaction with ozone or by providing a surface for heterogeneous processes include the particulates Al2O3, ice, and soot. These topics are discussed in terms of the possible effects of rocket exhausts on stratospheric ozone

    Twenty putative palmitoyl-acyl transferase genes with distinct expression patterns in Arabidopsis thaliana

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    Palmitoylation is a reversible posttranslational addition of palmitate to cysteine residues in proteins through a thioester bond by a family of DHHC (Asp-His-His-Cys) palmitoyltransferases (PATs) involved in cellular signaling, membrane trafficking, and synaptic transmission. There are 20 genes containing DHHC domain predicted to encode putative palmitoyltransferase in Arabidopsis thaliana genome. However, little is known about their characteristics such as genetic relationship and expression profile. Here, we present an overview of the putative PAT genes in A. thaliana focusing on their phylogeny, gene structure and expression profiles in different tissues and under different stresses. Besides conserved DHHC domain, the identity of their cDNA sequences was from 30 to 60%. Temprospatial expression profile of each putative gene of the entire PAT family showed that nineteen of twenty putative PAT members differently expressed in flowers, leaves, stems, roots, seedlings, young and old siliques except At2g40990. Among these nineteen expressed putative PATs, some members expressed at very high levels in certain tissue and some exhibited more even distribution in different tissues. This is the first report on the expression patterns of all these putative PAT genes, which will provide important fundamental data for further identification of their biological functions.Key words: Palmitoylation, palmitoyltransferase, Arabidopsis thaliana, expression pattern
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