857 research outputs found

    Release of noble gases and nitrogen from grain-surface sites in lunar ilmenite by closed-system oxidation

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    Noble gases and nitrogen were extracted from a 100 to 150 microns ilmenite separate from lunar soil 71501 by closed system stepped heating in approx. 10 torr O2 at 300 C, 400 C, 500 C, 600 C and 630 C, followed by stepped pyrolysis at ten temperatures between 680 C and approx. 1500 C. The five oxidation steps together liberated approx. 65% of the total He-4, 45% of the Ne-20, 23% of the N-14 and Ar-36, 12% of the Kr-84 and 8% of the Xe-132 in the sample; Ne-20/Ar-36 and Ne-20/Ne-22 ratios agree with the solar wind composition experiment, and Kr-84/Ar-36 and Xe-132/Ar-36 are within approx. 10% of Cameron's estimates for the sun and solar wind. The remaining gases, released above 630 C by pyrolysis, are strongly fractionated with respect to the SWC-Cameron solar wind elemental composition. Large concentrations of fractionated noble gases in grain interiors, their virtual absence in the relatively unfractionated surface gas reservoir, and the high N/noble gas ratio all imply that most of the solar wind noble gases initially implanted in grain surfaces are eventually lost by diffusion. Loss limits can be estimated by considering two given scenarios. It is concluded tat approx. 70 to 97% or more of the Ar implanted in 71501 ilmenite grains has diffusively escaped

    EVALUATION OF SPEED-TESTS FOR PLAYERS OF SPORT GAMES

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    PROBLEM. The characteristics demands of the load of the common sport games are different, but many similarities are obvious. 'They all require a high ability of anticipation. reaction- and action speed. Many actions like dribbling, feint. tracing and attacking adversary are carried out with highest intensity (speed) in combination with rapid changes in direction of motion In split seconds decisions between alternative movements must be reached and go into action. The available speed tests were not able to satis6 these requirements (e.g. 1, 2). The aim of this study was to evaluate tests for speed-diagnostics. which consider the specific demands of the sport games soccer, handball, tennis. MEI'HODS The length of the run and the kind of changes of direction depends on the conditions of the sport game For the time recording we used a measuring system of 4 double lightbars Each run starts from a defined position on a contact platform. The starts were free selected and/or given by an optical signal. The following abilities here recorded differently in separate tests: 4 the ability to start and accelerate straight on. I3 the ability to start. decelerate. accelerate in connection with changes in direction of motion the ability to react in connection \kith selection and following game specific movement. calculated by test-retest correlation coefficient To check the selectivity of the tests analysis of variance were used to calculate significant differences. KESliL.T.5 - the reliability of the evaluated tests are in the range of rtt = 72 - .98. and therefore altogether acceptable - the selectivity of the tests is also acceptable in general ( exception. test .4 for Tennis plavers). - the great intraindividuell differences between runners with turns to the left and right. as well as between the players within a team illustrate the necessarity from precise diagnostics A few number of training sessions will eliminate individual deficit

    A note on shell models for MHD Turbulence

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    We investigate the time evolution of two different (GOY-like) shell models which have been recently proposed to describe the gross features of MHD turbulence. We see that, even if they are formally of the same type sharing with MHD equations quadratic couplings and similar conserved quantities, fundamental differences exist which are related to the ideal invariants.Comment: 6 pages, 5 figures.eps, to appear in Europhysics Letter

    A Sparse Stress Model

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    Force-directed layout methods constitute the most common approach to draw general graphs. Among them, stress minimization produces layouts of comparatively high quality but also imposes comparatively high computational demands. We propose a speed-up method based on the aggregation of terms in the objective function. It is akin to aggregate repulsion from far-away nodes during spring embedding but transfers the idea from the layout space into a preprocessing phase. An initial experimental study informs a method to select representatives, and subsequent more extensive experiments indicate that our method yields better approximations of minimum-stress layouts in less time than related methods.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

    Resilient Placement of VNFs and Distributed MANO Components in a WMN-based NFV Infrastructure

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    Wireless Multi-Radio Outdoor-Routers are building a Wireless Mesh Network (WMN), which is used as an emergency communication infrastructure in case a disaster destroyed the existing communication system. A dynamic service provisioning shall be achieved by integrating Network Function Virtualisation (NFV) into the network. A distributed management and orchestration (MANO), which operates in-band of the network, controls the NFV infrastructure (NFVI). The primary goal of the distributed MANO consists of improving the network resilience to changes affecting the NFVI, namely node and link failures. For this aspect, the position of the Virtual Network Functions (VNFs), implementing a functional service component, as well as the position of the components building the distributed MANO within the WMN-based NFVI is essential. For this purpose, this publication proposes a concept for the resilient placement of the VNFs and distributed MANO components required within the WMN-based NFVI. Furthermore, a mathematical model of the network and an Integer Linear Programming (ILP) based optimisation target for implementing the concept are proposed. The optimisation target considers the connectivity of NFVI-Nodes at the placement by preferring well-connected NFVI-Nodes and avoiding poorly-connected ones. If required due to limited hardware resources, priorities among the different kinds of network functions are considered. Multiple existing solvers are used on the optimisation target to evaluate their performance in terms of their required time for providing an optimal solution based on different network sizes

    The RNA helicase database

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    RNA helicases are ubiquitous and essential enzymes that function in nearly all aspects of RNA metabolism. The RNA helicase database (www.rnahelicase.org) integrates the wealth of accumulating information on RNA helicases in a readily accessible format. The database is a portal that allows straightforward retrieval of comprehensive information on sequence, structure and on biochemical and cellular functions of all RNA helicases from the most widely used model organisms Escherichia coli, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mouse and human. Also included are RNA helicases from other organisms that are subject to specific investigation. The database is structured according to the most recent helicase classification into helicase superfamilies (SFs) and families, and thus emphasizes phyologenetic relations between RNA helicases as well. Information on individual RNA helicases can be accessed through various browsing routes or through text-based searches of the database

    Predictors of state-of-the-art management of early breast cancer in Switzerland

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    Background: The aim of this study was to investigate predictors of state-of-the-art management of early breast cancer in Switzerland. Patients and methods: The study included 3499 women aged 25-79 years diagnosed with invasive breast cancer stages I-IIIA in 2003-2005. Patients were identified through population-based cancer registries and treated in all kinds of settings. Concordance with national and international recommendations was assessed for 10 items covering surgery, radiotherapy, systemic adjuvant therapy and histopathology reporting. We used multivariate logistic regression to identify independent predictors of high (10 points) and low (≤7 points) concordance. Results: In one-third of the patients, management met guidelines in all items, whereas in about one-fifth, three or more items did not comply. Treatment by a surgeon with caseload in the upper tercile and team involved in clinical research were independent predictors of a high score, whereas treatment by a surgeon with a caseload in the lower tercile was associated with a low score. Socioeconomic characteristics such as income and education were not independent predictors, but patient's place of residence and age independently predicted management according to recommendations. Conclusion: Specialization and involvement in clinical research seem to be key elements for enhancing the quality of early breast cancer management at population leve
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