14,523 research outputs found

    Surface properties of ocean fronts

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    Background information on oceanic fronts is presented and the results of several models which were developed to study the dynamics of oceanic fronts and their effects on various surface properties are described. The details of the four numerical models used in these studies are given in separate appendices which contain all of the physical equations, program documentation and running instructions for the models

    Critical exponents of a three dimensional O(4) spin model

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    By Monte Carlo simulation we study the critical exponents governing the transition of the three-dimensional classical O(4) Heisenberg model, which is considered to be in the same universality class as the finite-temperature QCD with massless two flavors. We use the single cluster algorithm and the histogram reweighting technique to obtain observables at the critical temperature. After estimating an accurate value of the inverse critical temperature \Kc=0.9360(1), we make non-perturbative estimates for various critical exponents by finite-size scaling analysis. They are in excellent agreement with those obtained with the 4−ϔ4-\epsilon expansion method with errors reduced to about halves of them.Comment: 25 pages with 8 PS figures, LaTeX, UTHEP-28

    From Uncertainty Data to Robust Policies for Temporal Logic Planning

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    We consider the problem of synthesizing robust disturbance feedback policies for systems performing complex tasks. We formulate the tasks as linear temporal logic specifications and encode them into an optimization framework via mixed-integer constraints. Both the system dynamics and the specifications are known but affected by uncertainty. The distribution of the uncertainty is unknown, however realizations can be obtained. We introduce a data-driven approach where the constraints are fulfilled for a set of realizations and provide probabilistic generalization guarantees as a function of the number of considered realizations. We use separate chance constraints for the satisfaction of the specification and operational constraints. This allows us to quantify their violation probabilities independently. We compute disturbance feedback policies as solutions of mixed-integer linear or quadratic optimization problems. By using feedback we can exploit information of past realizations and provide feasibility for a wider range of situations compared to static input sequences. We demonstrate the proposed method on two robust motion-planning case studies for autonomous driving

    Radio-quiet and radio-loud pulsars: similar in Gamma-rays but different in X-rays

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    We present new Chandra and XMM-Newton observations of a sample of eight radio-quiet Gamma-ray pulsars detected by the Fermi Large Area Telescope. For all eight pulsars we identify the X-ray counterpart, based on the X-ray source localization and the best position obtained from Gamma-ray pulsar timing. For PSR J2030+4415 we found evidence for an about 10 arcsec-long pulsar wind nebula. Our new results consolidate the work from Marelli et al. 2011 and confirm that, on average, the Gamma-ray--to--X-ray flux ratios (Fgamma/Fx) of radio-quiet pulsars are higher than for the radio-loud ones. Furthermore, while the Fgamma/Fx distribution features a single peak for the radio-quiet pulsars, the distribution is more dispersed for the radio-loud ones, possibly showing two peaks. We discuss possible implications of these different distributions based on current models for pulsar X-ray emission.Comment: Accepted for publication in The Astrophysical Journal; 12 pages, 3 figures, 2 table

    Development of specifications for surface and subsurface oceanic environmental data

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    The existing need for synoptic subsurface observations was demonstrated giving special attention to the requirements of meteorology. The current state of synoptic oceanographic observations was assessed; a preliminary design for the Basic Observational Network needed to fulfill the minimum needs of synoptic meteorology and oceanography was presented. There is an existing critical need for such a network in the support of atmospheric modeling and operational meteorological prediction, and through utilization of the regional water mass concept an adequate observational system can be designed which is realistic in terms of cost and effort

    Androgenisierung

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    Zusammenfassung: Hirsutismus, androgenetische Alopezie und Akne als Zeichen der Androgenisierung zĂ€hlen zu den hĂ€ufigsten GrĂŒnden fĂŒr ambulante gynĂ€kologische Konsultationen. Das diagnostisch-therapeutische Vorgehen richtet sich nach dem Schweregrad und der Progression der Symptomentwicklung. Die Beurteilung der Therapiewirksamkeit erfordert meist Geduld. Eine Zusammenarbeit zwischen GynĂ€kologie und Dermatologie ist hĂ€ufig sinnvoll. Der Fokus dieses Beitrags liegt auf der Androgenisierung wĂ€hrend der reproduktiven Lebensphase. Etwaige Besonderheiten in der Postmenopause werden hervorgehoben. Eine Androgenisierung vor der PubertĂ€t, bei Kinderwunsch und in der Schwangerschaft wird nicht berĂŒcksichtig
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