583 research outputs found

    Das bandkeramische GrĂ€berfeld vom „ViesenhĂ€user Hof“ bei Stuttgart-MĂŒhlhausen: Neue Untersuchungsergebnisse zum Migrationsverhalten im frĂŒhen Neolithikum

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    Einleitung: Gegenstand des vorliegenden Beitrags ist die Rolle der MobilitĂ€t im Leben der frĂŒhen Ackerbauern und ViehzĂŒchter in SĂŒdwestdeutschland. Seit Jahrzehnten werden wissenschaftliche Auseinandersetzungen ĂŒber die Bedeutung von Wanderungsbewegungen bei der Ausbreitung der produzierenden Wirtschaftsweise in Europa zwischen 7000 und 4000 v. Chr. gefĂŒhrt. Dabei gehen traditionelle Überlegungen davon aus, dass die ersten Ackerbauern in Mitteleuropa Zuwanderer waren, die ein ‚Paket‘ neuer Errungenschaften und Ideen mit sich fĂŒhrten, das u. a. Haustiere, dauerhafte Siedlungen, Keramik und den Ackerbau enthielt.1 Neuere Untersuchungen und Überlegungen gestehen dagegen der einheimischen Bevölkerung eine maßgebliche Bedeutung bei der Übernahme der neolithischen Wirtschaftsweise zu.2 Die MobilitĂ€t des Menschen ist aber nicht nur fĂŒr die ErklĂ€rung des Neolithisierungsprozesses, sondern auch fĂŒr das VerstĂ€ndnis der Lebens- und Wirtschaftsweise der Menschen in den mittleren und spĂ€teren Abschnitten der Linearbandkeramik von höchstem Interesse. Die bisherige Forschungsdiskussion basierte in diesem Zusammenhang ĂŒberwiegend auf indirekten Argumenten, d. h. auf Artefakten, die auch getauscht oder gestohlen worden sein konnten, aber nicht auf den Überresten der potenziellen Zuwanderer selbst, die in Form von Knochen und ZĂ€hnen erhalten sind. Die vorliegende Studie bedient sich der direkten Analyse menschlicher Skelettreste der bandkeramischen GrĂ€ber vom ‚ViesenhĂ€user Hof‘, Stuttgart-MĂŒhlhausen, mittels anthropologischer Untersuchungen und Strontiumisotopenanalysen. Nachfolgend werden der Fundplatz in seinem archĂ€ologischen Kontext der Linearbandkeramik sowie die Ergebnisse der anthropologischen Untersuchungen und Strontiumisotopenanalysen vorgestellt und dann die Rolle der MobilitĂ€t im Leben der frĂŒhen Ackerbauern und ViehzĂŒchter sowie fĂŒr die Ausbreitung der neolithischen Wirtschaftsweise diskutiert. Stuttgart-MĂŒhlhausen ist eines der Ă€ltesten bandkeramischen GrĂ€berfelder, die bislang fĂŒr derartige Untersuchungen zur VerfĂŒgung standen

    Antiprotons at Solar Maximum

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    New measurements with good statistics will make it possible to observe the time variation of cosmic antiprotons at 1 AU through the approaching peak of solar activity. We report a new computation of the interstellar antiproton spectrum expected from collisions between cosmic protons and the interstellar gas. This spectrum is then used as input to a steady-state drift model of solar modulation, in order to provide predictions for the antiproton spectrum as well as the antiproton/proton ratio at 1 AU. Our model predicts a surprisingly large, rapid increase in the antiproton/proton ratio through the next solar maximum, followed by a large excursion in the ratio during the following decade.New measurements with good statistics will make it possible to observe the time variation of cosmic antiprotons at 1 AU through the approaching peak of solar activity. We report a new computation of the interstellar antiproton spectrum expected from collisions between cosmic protons and the interstellar gas. This spectrum is then used as input to a steady-state drift model of solar modulation, in order to provide predictions for the antiproton spectrum as well as the antiproton/proton ratio at 1 AU. Our model predicts a surprisingly large, rapid increase in the antiproton/proton ratio through the next solar maximum, followed by a large excursion in the ratio during the following decade

    Formation of soliton trains in Bose-Einstein condensates as a nonlinear Fresnel diffraction of matter waves

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    The problem of generation of atomic soliton trains in elongated Bose-Einstein condensates is considered in framework of Whitham theory of modulations of nonlinear waves. Complete analytical solution is presented for the case when the initial density distribution has sharp enough boundaries. In this case the process of soliton train formation can be viewed as a nonlinear Fresnel diffraction of matter waves. Theoretical predictions are compared with results of numerical simulations of one- and three-dimensional Gross-Pitaevskii equation and with experimental data on formation of Bose-Einstein bright solitons in cigar-shaped traps.Comment: 8 pages, 3 figure

    Bridging the gap between complexity science and clinical practice by formalizing idiographic theories: a computational model of functional analysis

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    Background: The past decades of research have seen an increase in statistical tools to explore the complex dynamics of mental health from patient data, yet the application of these tools in clinical practice remains uncommon. This is surprising, given that clinical reasoning, e.g., case conceptualizations, largely coincides with the dynamical system approach. We argue that the gap between statistical tools and clinical practice can partly be explained by the fact that current estimation techniques disregard theoretical and practical considerations relevant to psychotherapy. To address this issue, we propose that case conceptualizations should be formalized. We illustrate this approach by introducing a computational model of functional analysis, a framework commonly used by practitioners to formulate case conceptualizations and design patient-tailored treatment. Methods: We outline the general approach of formalizing idiographic theories, drawing on the example of a functional analysis for a patient suffering from panic disorder. We specified the system using a series of differential equations and simulated different scenarios; first, we simulated data without intervening in the system to examine the effects of avoidant coping on the development of panic symptomatic. Second, we formalized two interventions commonly used in cognitive behavioral therapy (CBT; exposure and cognitive reappraisal) and subsequently simulated their effects on the system. Results: The first simulation showed that the specified system could recover several aspects of the phenomenon (panic disorder), however, also showed some incongruency with the nature of panic attacks (e.g., rapid decreases were not observed). The second simulation study illustrated differential effects of CBT interventions for this patient. All tested interventions could decrease panic levels in the system. Conclusions: Formalizing idiographic theories is promising in bridging the gap between complexity science and clinical practice and can help foster more rigorous scientific practices in psychotherapy, through enhancing theory development. More precise case conceptualizations could potentially improve intervention planning and treatment outcomes. We discuss applications in psychotherapy and future directions, amongst others barriers for systematic theory evaluation and extending the framework to incorporate interactions between individual systems, relevant for modeling social learning processes. With this report, we hope to stimulate future efforts in formalizing clinical frameworks

    Safe use of proton pump inhibitors in patients with cirrhosis

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    Contains fulltext : 194399.pdf (publisher's version ) (Open Access

    Polyhedral Analysis using Parametric Objectives

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    The abstract domain of polyhedra lies at the heart of many program analysis techniques. However, its operations can be expensive, precluding their application to polyhedra that involve many variables. This paper describes a new approach to computing polyhedral domain operations. The core of this approach is an algorithm to calculate variable elimination (projection) based on parametric linear programming. The algorithm enumerates only non-redundant inequalities of the projection space, hence permits anytime approximation of the output

    Teacher Ratings of Children's Behavior Problems and Functional Impairment Across Gender and Ethnicity:Construct Equivalence of the Strengths and Difficulties Questionnaire

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    The present study examined construct equivalence of the teacher Strengths and Difficulties Questionnaire and compared mean scores in an ethnically diverse sample of children living in the Netherlands. Elementary schoolteachers completed the Strengths and Difficulties Questionnaire for 2,185 children aged 6 to 10 years of the four largest ethnic groups in the Netherlands, namely native Dutch (n = 684) and Moroccan (n = 702), Turkish (n = 434), and Surinamese (n = 365) immigrant children. Multigroup confirmatory factor analysis suggested the factor structure of the Strengths and Difficulties Questionnaire to be invariant across children's ethnicity and gender. Additionally, the factor structure appeared to be similar for Dutch and Surinamese teachers. However, mean scores on emotional problems, hyperactivity, conduct problems, prosocial behavior, and impairment varied significantly according to ethnicity and gender. Mean scores on peer problems differed significantly for boys and girls, but not across ethnicity. Whether mean differences reflect a method bias or actual differences in classroom behaviors is discussed and needs further research

    Safe use of proton pump inhibitors in patients with cirrhosis

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    Aims: Proton pump inhibitors (PPIs) belong to the most frequently used drugs, also in patients with cirrhosis. PPIs are extensively metabolized by the liver, but practice guidance on prescribing in cirrhosis is lacking. We aim to develop practical guidance on the safe use of PPIs in patients with cirrhosis. Methods: A systematic literature search identified studies on the safety (i.e. adverse events) and pharmacokinetics of PPIs in cirrhotic patients. This evidence and data from the product information was reviewed by an expert panel who classified drugs as safe; no additional risks known; additional risks known; unsafe; or unknown. Guidance was aimed at the oral use of PPIs and categorized by the severity of cirrhosis, using the Child–Turcotte–Pugh (CTP) classification. Results: A total of 69 studies were included. Esomeprazole, omeprazole and rabeprazole were classified as having ‘no additional risks known’. A reduction in maximum dose of omeprazole and rabeprazole is recommended for CTP A and B patients. For patients with CTP C cirrhosis, the only PPI advised is esomeprazole at a maximum dosage of 20 mg per day. Pantoprazole and lansoprazole were classified as unsafe because of 4- to 8-fold increased exposure. The use of PPIs in cirrhotic patients has been associated with the development of infections and hepatic encephalopathy and should be carefully considered. Conclusions: We suggest using esomeprazole, omeprazole or rabeprazole in patients with CTP A or B cirrhosis and only esomeprazole in patients with CTP C. Pharmacokinetic changes are also important to consider when prescribing PPIs to vulnerable, cirrhotic patients

    Coarse-Grained Finite-Temperature Theory for the Condensate in Optical Lattices

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    In this work, we derive a coarse-grained finite-temperature theory for a Bose condensate in a one-dimensional optical lattice, in addition to a confining harmonic trap potential. We start from a two-particle irreducible (2PI) effective action on the Schwinger-Keldysh closed-time contour path. In principle, this action involves all information of equilibrium and non-equilibrium properties of the condensate and noncondensate atoms. By assuming an ansatz for the variational function, i.e., the condensate order parameter in an effective action, we derive a coarse-grained effective action, which describes the dynamics on the length scale much longer than a lattice constant. Using the variational principle, coarse-grained equations of motion for the condensate variables are obtained. These equations include a dissipative term due to collisions between condensate and noncondensate atoms, as well as noncondensate mean-field. To illustrate the usefulness of our formalism, we discuss a Landau instability of the condensate in optical lattices by using the coarse-grained generalized Gross-Pitaevskii hydrodynamics. We found that the collisional damping rate due to collisions between the condensate and noncondensate atoms changes sign when the condensate velocity exceeds a renormalized sound velocity, leading to a Landau instability consistent with the Landau criterion. Our results in this work give an insight into the microscopic origin of the Landau instability.Comment: 38 pages, 2 figures. Submitted to Journal of Low Temperature Physic

    Vortex dynamics in trapped Bose-Einstein condensate

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    We perform numerical simulations of vortex motion in a trapped Bose-Einstein condensate by solving the two-dimensional Gross-Pitaevskii Equation in the presence of a simple phenomenological model of interaction between the condensate and the finite temperature thermal cloud. At zero temperature, the trajectories of a single, off - centred vortex precessing in the condensate, and of a vortex - antivortex pair orbiting within the trap, excite acoustic emission. At finite temperatures the vortices move to the edge of the condensate and vanish. By fitting the finite -temperature trajectories, we relate the phenomenological damping parameter to the friction coefficients α\alpha and αâ€Č\alpha^{'}, which are used to describe the interaction between quantised vortices and the normal fluid in superfluid helium.Comment: 16 pages, 18 figures, published in JLT
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