1,436 research outputs found

    Surveyor batteries Final engineering report

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    Design and performance of Surveyor spacecraft silver-zinc main batter

    Outbreak of tropical rat mite (Ornithonyssus bacoti) dermatitis in a home for disabled persons

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    Five mentally handicapped individuals living in a home for disabled persons in Southern Germany were seen in our outpatient department with pruritic, red papules predominantly located in groups on the upper extremities, neck, upper trunk and face. Over several weeks 40 inhabitants and 5 caretakers were affected by the same rash. Inspection of their home and the sheds nearby disclosed infestation with rat populations and mites. Finally the diagnosis of tropical rat mite dermatitis was made by the identification of the arthropod Ornithonyssus bacoti or so-called tropical rat mite. The patients were treated with topical corticosteroids and antihistamines. After elimination of the rats and disinfection of the rooms by a professional exterminator no new cases of rat mite dermatitis occurred. The tropical rat mite is an external parasite occurring on rats, mice, gerbils, hamsters and various other small mammals. When the principal animal host is not available, human beings can become the victim of mite infestation. Copyright (c) 2007 S. Karger AG, Base

    Evaluation of flight foods under hypokinetic conditions, part 2, chapters 4 and 5

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    Effects of weightlessness on body temperature and heart rate determined by 56 day bed rest stud

    Random walks near Rokhsar-Kivelson points

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    There is a class of quantum Hamiltonians known as Rokhsar-Kivelson(RK)-Hamiltonians for which static ground state properties can be obtained by evaluating thermal expectation values for classical models. The ground state of an RK-Hamiltonian is known explicitly, and its dynamical properties can be obtained by performing a classical Monte Carlo simulation. We discuss the details of a Diffusion Monte Carlo method that is a good tool for studying statics and dynamics of perturbed RK-Hamiltonians without time discretization errors. As a general result we point out that the relation between the quantum dynamics and classical Monte Carlo simulations for RK-Hamiltonians follows from the known fact that the imaginary-time evolution operator that describes optimal importance sampling, in which the exact ground state is used as guiding function, is Markovian. Thus quantum dynamics can be studied by a classical Monte Carlo simulation for any Hamiltonian that is free of the sign problem provided its ground state is known explicitly.Comment: 12 pages, 9 figures, RevTe

    Optimization of ground and excited state wavefunctions and van der Waals clusters

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    A quantum Monte Carlo method is introduced to optimize excited state trial wavefunctions. The method is applied in a correlation function Monte Carlo calculation to compute ground and excited state energies of bosonic van der Waals clusters of upto seven particles. The calculations are performed using trial wavefunctions with general three-body correlations

    Divergent evolutionary trajectories of bryophytes and tracheophytes from a complex common ancestor of land plants

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    The origin of plants and their colonization of land fundamentally transformed the terrestrial environment. Here we elucidate the basis of this formative episode in Earth history through patterns of lineage, gene and genome evolution. We use new fossil calibrations, a relative clade age calibration (informed by horizontal gene transfer) and new phylogenomic methods for mapping gene family origins. Distinct rooting strategies resolve tracheophytes (vascular plants) and bryophytes (non-vascular plants) as monophyletic sister groups that diverged during the Cambrian, 515–494 million years ago. The embryophyte stem is characterized by a burst of gene innovation, while bryophytes subsequently experienced an equally dramatic episode of reductive genome evolution in which they lost genes associated with the elaboration of vasculature and the stomatal complex. Overall, our analyses reveal that extant tracheophytes and bryophytes are both highly derived from a more complex ancestral land plant. Understanding the origin of land plants requires tracing character evolution across a diversity of modern lineages

    Topologically disordered systems at the glass transition

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    The thermodynamic approach to the viscosity and fragility of amorphous oxides was used to determine the topological characteristics of the disordered network-forming systems. Instead of the disordered system of atoms we considered the congruent disordered system of interconnecting bonds. The Gibbs free energy of network-breaking defects (configurons) was found based on available viscosity data. Amorphous silica and germania were used as reference disordered systems for which we found an excellent agreement of calculated and measured glass transition temperatures. We reveal that the Hausdorff dimension of the system of bonds changes from Euclidian three-dimensional below to fractal 2.55 ± 0.05-dimensional geometry above the glass transition temperature

    Public crises, public futures

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    This article begins to map out a novel approach to analyzing contemporary contexts of public crisis, relationships between them and possibilities that these scenes hold out for politics. The article illustrates and analyses a small selection of examples of these kinds of contemporary scenes and calls for greater attention to be given to the conditions and consequences of different forms and practices of public and political mediation. In offering a three-fold typology to delineate differences between ‘abject’, ‘audience’ and ‘agentic’ publics the article begins to draw out how political and public futures may be seen as being bound up with how the potentialities, capacities and qualities that publics are imagined to have and resourced to perform. Public action and future publics are therefore analysed here in relation to different versions of contemporary crisis and the political concerns and publics these crises work to articulate, foreground and imaginatively and practically support

    Transfer-Matrix Monte Carlo Estimates of Critical Points in the Simple Cubic Ising, Planar and Heisenberg Models

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    The principle and the efficiency of the Monte Carlo transfer-matrix algorithm are discussed. Enhancements of this algorithm are illustrated by applications to several phase transitions in lattice spin models. We demonstrate how the statistical noise can be reduced considerably by a similarity transformation of the transfer matrix using a variational estimate of its leading eigenvector, in analogy with a common practice in various quantum Monte Carlo techniques. Here we take the two-dimensional coupled XYXY-Ising model as an example. Furthermore, we calculate interface free energies of finite three-dimensional O(nn) models, for the three cases n=1n=1, 2 and 3. Application of finite-size scaling to the numerical results yields estimates of the critical points of these three models. The statistical precision of the estimates is satisfactory for the modest amount of computer time spent

    Young European citizens : An individual by context perspective on adolescent European citizenship

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    This study examined the effects of individual, school-level and country-level variables and their interactions on two components of adolescents’ active European citizenship: trust in European institutions and participation at the European level. For comparison, country-related institutional trust and participation were also predicted. Using multilevel regression models, we re-analysed a subsample of survey data from the International Civic and Citizenship Education Study, collected from 14-year-old students (n = 72,466) in 22 European countries in 2009. Results showed that higher cognitive engagement with politics (e.g., political interest), more opportunities for learning about Europe at school, and country wealth and social equality were positively associated with both aspects of adolescents’ active European citizenship. In contrast to country-related participation, the participatory dimension of active European citizenship was also positively related to a higher socioeconomic status of adolescent’s classroom and family, an association that was more pronounced in less wealthy and post-communist countries
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