3,357 research outputs found

    LOADS: a computer program for determining the shear, bending moment and axial loads for fuselage type structures

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    LOADS determines rigid body vehicle shears, bending moments and axial loads on a space vehicle due to aerodynamic loads and propellant inertial loads. An example hand calculation is presented and was used to check LOADS. A brief description of the program and the equations used are presented. LOADS is operational on the Univac 1110, occupies 10505 core and typically takes less than one(1) second of CAU time to execute

    LiFE Assessment Tool

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    As part of an ongoing study to construct a molecular Turing machine in which a polymer chain is encoded via allosteric information transfer between macrocyclic complexes, we describe the thermodynamic and kinetic characterization of a multicomponent self-assembled system based on a zinc porphyrin macrocyclic compound, a bidentate ligand (1,4-diazabicyclo[2.2.2]octane, DABCO), and a viologen-substituted polymer guest. Initial addition of DABCO to the porphyrin macrocycle in chloroform solution leads to the formation of a stable 2:1 (porphyrin:DABCO) dimeric complex, even under dilute conditions, by means of strong cooperative interactions involving hydrogen and metal-ligand bonds. Further titration of the porphyrin-DABCO mixtures with the polymer gives rise to a complex array of species in the solution. The system is analyzed in detail by a combination of spectroscopic measurements and computational modeling. Each association constant in the binding scheme and the fraction of each individual complex that is formed in solution are determined precisely using a mass-balance model. Kinetic studies revealed that the rates of the polymer threading and dethreading in and out of the dimeric system are remarkably slow, indicating that the polymer is locked inside the cavity of the stable 2:1 dimeric complex as a result of strong allosteric interactions

    Економіко-правове забезпечення формування та реалізації соціальної політики держави, регіону, міста

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    У статті визначено потребу послідовного правового забезпечення формування та реалізації соціальної політики в багаторівневій системі управління. Обґрунтовано зміст та особливості соціальної політики залежно від рівня управління. Сформульовано пропозиції з удосконалення соціальної політики держави та її регіонів, виконано їх правову регламентацію

    Nondegenerate Fermions in the Background of the Sphaleron Barrier

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    We consider level crossing in the background of the sphaleron barrier for nondegenerate fermions. The mass splitting within the fermion doublets allows only for an axially symmetric ansatz for the fermion fields. In the background of the sphaleron we solve the partial differential equations for the fermion functions. We find little angular dependence for our choice of ansatz. We therefore propose a good approximate ansatz with radial functions only. We generalize this approximate ansatz with radial functions only to fermions in the background of the sphaleron barrier and argue, that it is a good approximation there, too.Comment: LATEX, 20 pages, 11 figure

    Delineation of a unique protein-protein interaction site on the surface of the estrogen receptor

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    Recent studies have identified a series of estrogen receptor (ER)interacting peptides that recognize sites that are distinct from the classic coregulator recruitment (AF2) region. Here, we report the structural and functional characterization of an ER alpha-specific peptide that binds to the liganded receptor in an AF2-independent manner. The 2-angstrom crystal structure of the ER/peptide complex reveals a binding site that is centered on a shallow depression on the beta-hairpin face of the ligand-binding domain. The peptide binds in an unusual extended conformation and makes multiple contacts with the ligand-binding domain. The location and architecture of the binding site provides an insight into the peptide's ER subtype specificity and ligand interaction preferences. In vivo, an engineered coactivator containing the peptide motif is able to strongly enhance the transcriptional activity of liganded ER alpha, particularly in the presence of 4-hydroxytamoxifen. Furthermore, disruption of this binding surface alters ER's response to the coregulator TIF2. Together, these results indicate that this previously unknown interaction site represents a bona fide control surface involved in regulating receptor activity

    SCOPE: a scorecard for osteoporosis in Europe

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    Summary The scorecard summarises key indicators of the burden of osteoporosis and its management in each of the member states of the European Union. The resulting scorecard elements were then assembled on a single sheet to provide a unique overview of osteoporosis in Europe. Introduction The scorecard for osteoporosis in Europe (SCOPE) is an independent project that seeks to raise awareness of osteoporosis care in Europe. The aim of this project was to develop a scorecard and background documents to draw attention to gaps and inequalities in the provision of primary and secondary prevention of fractures due to osteoporosis. Methods The SCOPE panel reviewed the information available on osteoporosis and the resulting fractures for each of the 27 countries of the European Union (EU27). The information researched covered four domains: background information (e.g. the burden of osteoporosis and fractures), policy framework, service provision and service uptake e.g. the proportion of men and women at high risk that do not receive treatment (the treatment gap). Results There was a marked difference in fracture risk among the EU27. Of concern was the marked heterogeneity in the policy framework, service provision and service uptake for osteoporotic fracture that bore little relation to the fracture burden. For example, despite the wide availability of treatments to prevent fractures, in the majority of the EU27, only a minority of patients at high risk receive treatment for osteoporosis even after their first fracture. The elements of each domain in each country were scored and coded using a traffic light system (red, orange, green) and used to synthesise a scorecard. The resulting scorecard elements were then assembled on a single sheet to provide a unique overview of osteoporosis in Europe. Conclusions The scorecard will enable healthcare professionals and policy makers to assess their country’s general approach to the disease and provide indicators to inform future provision of healthcare

    Interferometry with Bose-Einstein Condensates in Microgravity

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    Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Due to their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this paper we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far-field of a double-slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.Comment: 8 pages, 3 figures; 8 pages of supporting materia

    Electronic structure of strained InP/GaInP quantum dots

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    We calculate the electronic structure of nm scale InP islands embedded in Ga0.51In0.49PGa_{0.51}In_{0.49}P. The calculations are done in the envelope approximation and include the effects of strain, piezoelectric polarization, and mixing among 6 valence bands. The electrons are confined within the entire island, while the holes are confined to strain induced pockets. One pocket forms a ring at the bottom of the island near the substrate interface, while the other is above the island in the GaInP. The two sets of hole states are decoupled. Polarization dependent dipole matrix elements are calculated for both types of hole states.Comment: Typographical error corrected in strain Hamiltonia

    Measuring Health: A Multivariate Approach

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    We examined the health status of 171 countries by employing factor analysis on various national health indicators for the period 2000–2005 to construct two new measures on health. The first measure is based on the health of individuals and the second on (the quality of) the health services. Our measures differ substantially from indicators used in previous studies on health and also lead to different rankings of countries. As rankings are not that informative without further information, we analyzed the distance between each country and the sample mean. Differences between countries are much more pronounced for our measure on health services than for our measure on the health of individuals. Using cluster analysis, we classified the countries in six homogenous groups

    Aromaticity in a Surface Deposited Cluster: Pd4_4 on TiO2_2 (110)

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    We report the presence of \sigma-aromaticity in a surface deposited cluster, Pd4_4 on TiO2_2 (110). In the gas phase, Pd4_4 adopts a tetrahedral structure. However, surface binding promotes a flat, \sigma-aromatic cluster. This is the first time aromaticity is found in surface deposited clusters. Systems of this type emerge as a promising class of catalyst, and so realization of aromaticity in them may help to rationalize their reactivity and catalytic properties, as a function of cluster size and composition.Comment: 4 pages, 3 figure
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