160 research outputs found

    Perceptions of Electoral Fairness and Voter Turnout

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    Previous research has established a link between turnout and the extent to which voters are faced with a “meaningful” partisan choice in elections; this study extends the logic of this argument to perceptions of the “meaningfulness” of electoral conduct. It hypothesizes that perceptions of electoral integrity are positively related to turnout. The empirical analysis to test this hypothesis is based on aggregate-level data from 31 countries, combined with survey results from Module 1 of the Comparative Study of Electoral Systems survey project, which includes new and established democracies. Multilevel modeling is employed to control for a variety of individual- and election-level variables that have been found in previous research to influence turnout. The results of the analysis show that perceptions of electoral integrity are indeed positively associated with propensity to vote. </jats:p

    Induction and migration of cryptic/defective Salmonella enterica prophages as a consequence of infection with lytic phages is an additional factor in stability of a coevolutionary vector

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    The influence of infection of natural isolates of Salmonella enterica with lytic (nonlysogenic) phages on the expression of resident cryptic or defective prophages in host bacteria was studied. The induction of defective/cryptic phages after infection with nonlysogenic phages and packaging of bacterial chromosomal fragments in capsids of defective phages is demonstrated. This may lead to migration and wide distribution of both the genomes of defective phages per se and various fragments of the bacterial chromosome (including pathogenic islands) in new bacterial strains with concomitant change of their properties, the acquired new features of pathogenicity among them.This work was supported by EC PhageVet-P (contract no. FOOD-CT-2005-007224) and by the Russian Foundation for Basic Research (grant no. 08-04-00162-a). We gratefully acknowledge the support of organizations presenting the grants.info:eu-repo/semantics/publishedVersio

    Thermodynamics of pyrope-majorite, Mg3Al2Si3O12-Mg4Si4O12, solid solution from atomistic model calculations

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    Static lattice energy calculations, based on empirical pair potentials have been performed for a large set of different structures with compositions between pyrope and majorite, and with different states of order of octahedral cations. The energies have been cluster expanded using pair and quaternary terms. The derived ordering constants have been used to constrain Monte Carlo simulations of temperature-dependent properties in the ranges of 1073 3673K and 0 20 GPa. The free energies of mixing have been calculated using the method of thermodynamic integration. At zero pressure the cubic/tetragonal transition is predicted for pure majorite at 3300 K. The transition temperature decreases with the increase of the pyrope mole fraction. A miscibility gap associated with the transition starts to develop at about 2000K and xmaj 0.8, and widens with the decrease in temperature and the increase in pressure. Activity composition relations in the range of 0 20 GPa and 1073 2673K are described with the help of a high-order Redlich Kister polynomial

    A method of training multi-layer networks with heaviside characteristics using internal representations

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    Two algorithms have recently been reported for training multi-layer networks of neurons with Heaviside characteristics. In these the weights are treated as continuous random variables and the output of a neuron is probabilistic with a distribution that is a differentiable function of the weight parameters. A limitation of these methods is that they are restricted to networks with two layers of variable weights. Other algorithms have been developed for this problem which use internal representations to train networks with Heaviside characteristics. However these suffer from the need to perform "bit flipping" on the internal representations in an effort to reduce the output error and as a result these methods do not guarantee that the network will converge to a solution. We present a learning algorithm that employs internal representations, which are continuous random variables, for the training of multi-layer networks whose neurons have Heaviside characteristics. This algorithm is an improvement over the others in that it is applicable to networks with any number of layers of variable weights and does not require "bit flipping" on the internal representations to reduce output error. The algorithm is extended to apply to recurrent networks. Some illustrative results are given

    Historic evolution of a marsh island: Bloodsworth Island, Maryland

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    High rates of relative sea-level rise in the Chesapeake Bay of about 0.3 m/century has caused rapid land loss of the Bay islands. This study is the first quantitative analysis of both perimeter and interior land loss for one of the large marsh islands?Bloodsworth Island. A geographical information system (GIS) was used for the analysis at a resolution of about 16 meters. From 1849 to 1992, the area of Bloodsworth Island declined by 579 ha, or 26% of the land area in 1849. The land loss can be divided into four geomorphic types: perimeter land loss, channel widening, channel ponding, and non- channel ponding. Perimeter land loss is largest at 3.0 ha/yr from 1942 to 1992, but the three interior land loss types are also significant, totalling 1.6 ha/yr from 1942 to 1992. Channel ponding and widening were responsible for nearly all interior land loss prior to 1942. The initial formation of non- channel ponds is attributed to a short-term acceleration in sea-level rise (to 7 mm/yr from 1930 to 1948). Subsequently, non-channel ponding has been significant, particularly in the southeastern quadrant of the island. Compared to the mainland marshes, interior land loss has occurred at much slower rates; this is probably due to the low thickness of the marsh deposits on Bloodsworth. To date, bombing appears to have only had a secondary impact on land loss at the scale of this study. In the future, the island appears increasingly vulnerable to interior break- up, particularly given another short-term acceleration of sea-level rise

    Theoretical study of a five-coordinated silica polymorph

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    Theoretical calculations are performed to study transformations in silica as a function of nonhydrostatic stress. Molecular-dynamics calculations reveal a crystalline-to-crystalline transition from alpha-quartz to a phase with five-coordinated silicon (Si-V) at high pressure in the presence of deviatoric stress. The phase, which appears for specific orientations of the stress tensor relative to the crystallographic axes of quartz, is a crystalline polymorph of silica with five-coordinated silicon. The structure possesses P3(2)21 space-group symmetry. First-principles calculations within the local-density approximation, as well as molecular dynamics and energy minimization with interatomic potentials, find this phase to be mechanically and energetically stable with respect to quartz at high pressure. The calculated x-ray diffraction pattern and vibrational properties of the phase are reported. Upon decompression, the Si-V phase reverts to alpha-quartz through an intermediate four-coordinated phase and an unusual isosymmetrical phase transformation. The results suggest the importance of application of nonhydrostatic stress conditions in the design and synthesis of novel materials

    Human Differences in Navigational Approaches during Tele-Robotic Search

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    This study investigated the navigational approaches used by humans when operating a simple tele-robot in a simulated search and rescue operation. Tele-robots are being increasingly used in safety-critical operations. During tele-operation, the situational awareness of tele-robot operators needs to be supported. Navigation depends on psychological skills of perception and cognition, and can utlize different problem solving strategies. However, there is limited knowledge of how operators develop situational awareness while navigating tele-robots. The study was conducted to understand if there were distinctive, identifiable strategies in the way operators navigated. When participants manually tele-operated a robot in a remote physical environment, two distinct navigation strategies were found (labeled driver method and searcher method). The result of this work can be used to inform the design of human-centric tele-robot navigational algorithms that can support a variety of human navigation strategies.This is a proceeding from the Human Factors and Ergonomics Society Annual Meeting 57 (2013): 625, doi: 10.1177/1541931213571134. Posted with permission.</div
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