115 research outputs found

    Capillarity Theory for the Fly-Casting Mechanism

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    Biomolecular folding and function are often coupled. During molecular recognition events, one of the binding partners may transiently or partially unfold, allowing more rapid access to a binding site. We describe a simple model for this flycasting mechanism based on the capillarity approximation and polymer chain statistics. The model shows that flycasting is most effective when the protein unfolding barrier is small and the part of the chain which extends towards the target is relatively rigid. These features are often seen in known examples of flycasting in protein-DNA binding. Simulations of protein-DNA binding based on well-funneled native-topology models with electrostatic forces confirm the trends of the analytical theory

    Experimental results on strangeness production in proton-proton collisions at COSY

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    The production of K+ and K- mesons in elementary proton-proton collision has been investigated at the Cooler Synchrotron COSY in Juelich. A high quality proton beam with low emittance and small momentum spread permitted to study the creation of these mesons very close to the kinematical threshold. The energy dependence of the total cross section is investigated using internal beam facilities providing a high accuracy particle momentum determination as well as an external non-magnetic detection setup with a large geometrical acceptance. The determination of the four-momentum vectors for all ejectiles of each registered event gives the complete kinematical information allowing to study the interaction of the outgoing particles. Results on the performed studies of the pp --> pp K+ K-, pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions will be presented and their relevance to the interpretation of heavy ion collisions will be discussed.Comment: 8 pages, 6 figures, plenary talk at 6th International Conference On Strange Quarks in Matter: '2001 - A Flavorspace Odyssey' (SQM2001), Frankfurt, Germany, September 25-29, 2001, to be published in J. Phys. G: Nucl. Part. Phy

    Technical Design Report for the PANDA Solenoid and Dipole Spectrometer Magnets

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    This document is the Technical Design Report covering the two large spectrometer magnets of the PANDA detector set-up. It shows the conceptual design of the magnets and their anticipated performance. It precedes the tender and procurement of the magnets and, hence, is subject to possible modifications arising during this process.Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski, Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy), Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy

    Physics Performance Report for PANDA: Strong Interaction Studies with Antiprotons

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    To study fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei, the universal PANDA detector will be built. Gluonic excitations, the physics of strange and charm quarks and nucleon structure studies will be performed with unprecedented accuracy thereby allowing high-precision tests of the strong interaction. The proposed PANDA detector is a state-of-the art internal target detector at the HESR at FAIR allowing the detection and identification of neutral and charged particles generated within the relevant angular and energy range. This report presents a summary of the physics accessible at PANDA and what performance can be expected.Comment: 216 page

    Social Security Reform in the US: Lessons from Hungary

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    The partial privatization of the US Social Security system was clearly the top economic policy priority for the new Bush administration. While many famous economists, publicists and politicians support, others reject the partial privatization of the Social Security system. The international comparisons have been quite infrequent, concentrated on few countries (Chile, Great Britain and Sweden) and left out similar reforms introduced in similar situations, like in Hungary, Poland and other ex-communist countries. In this article I try to make up for this omission and outline the lessons from the Hungarian reform, started in 1998. The conclusion is simple: such a reform is possible but does not solve the problems of social security

    HIGH QUALITY SPEECH CODEC EMPLOYING SINES+NOISE+TRANSIENTS MODEL

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    A method of high quality wideband speech signal representation employing sines+transients+noise model is presented. The need for a wideband speech coding approach as well as various methods for analysis and synthesis of sines, residual and transient states of speech signal is discussed. The perceptual criterion is applied in the proposed approach during encoding of sines amplitudes in order to reduce bandwidth requirements and to preserve high quality of speech. Therefore, the psychoacoustic model devised for perceptual speech coding is presented. The experimental results reveal that method for tonality estimation employed in the psychoacoustic model has a significant impact on perceptual coding accuracy. Various methods for tonality estimation are presented and compared
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