20,876 research outputs found

    Age work in organizations: maintaining and disrupting institutionalized understandings of higher age

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    Age diversity research calls for new approaches in explaining the persistence of age inequalities, which integrate different levels of analysis and display greater context sensitivity. Concurrently, neoinstitutionalist research interested in social inequalities calls for merging institutional theory with critical perspectives and to account for issues of power. In this study, we address the calls of both research streams through developing the concept of ‘age work’: the institutional work actors undertake on age as a social institution. Applying our novel concept to a multi-actor study of four German organizations known for their age management, we come across a counterintuitive insight regarding actors’ age work: maintaining stereotypical age images can serve to counter age inequalities, whereas deconstructing age images can reinforce age inequalities. The multi-actor perspective of our study allows us to categorize different forms of power-laden and interest-driven age work and to portray the reproduction of age inequalities as a result of actors’ age work, embedded in different contexts and complex power relations. Comparing employees’ forms of age work across sectors and organizations, we detail how notions of masculinity as well as income and job security shaped the categorized forms of age work

    Out of equilibrium quantum field dynamics of an initial thermal state after a change in the external field

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    The effects of the initial temperature in the out of equilibrium quantum field dynamics in the presence of an homogeneous external field are investigated. We consider an initial thermal state of temperature T for a constant external field J. A subsequent sign flip of the external field, J to -J, gives rise to an out of equilibrium nonperturbative quantum field dynamics. The dynamics is studied here for the symmetry broken lambda(Phi^2)^2 scalar N component field theory in the large N limit. We find a dynamical effective potential for the expectation value that helps to understand the dynamics. The dynamics presents two regimes defined by the presence or absence of a temporal trapping close to the metastable equilibrium position of the potential. The two regimes are separated by a critical value of the external field that depends on the initial temperature. The temporal trapping is shorter for larger initial temperatures or larger external fields. Parametric resonances and spinodal instabilities amplify the quantum fluctuations in the field components transverse to the external field. When there is a temporal trapping this is the main mechanism that allows the system to escape from the metastable state for large N. Subsequently backreaction stops the growth of the quantum fluctuations and the system enters a quasiperiodic regime.Comment: LaTeX, 19 pages, 12 .eps figures, improved version to appear in Phys Rev

    X-ray characterisation of bulk stones from the patina to the depth stone

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    The aim of this study on monumental limestone alteration is to characterise the superficial stone called patina where transformation processes due to air and water occur. We present results on stones from the Chambord castle, so Tuffeau limestone, from the Loire Valley. Three samples has been studied and compared in relationship with their position on the monument (outside or inside). In order to describe these samples, different techniques have been used : chemical analysis, optical microscopy. The three main phases are calcite (CaCO 3), quartz and opal (SiO 2), with various granulometry. X-ray diffraction has been performed on bulk samples. A special sample holder allows to analyse very thin zones, so to describe the mineralogical composition from the epidermis to the depth stone [1]. The stones are constituted of small crystallites which differ in dimension and orientation. This conducts to a semi-quantitative description. Protecting layer of the stone is associated to the rate of dissolution of calcite in patina zone

    Did Board Configuration Matter? The Case of US Subprime Lenders

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    Research Question/Issue: The origins of the global financial crisis have been attributed to the combination of a housing price bubble and innovative financial instruments, as well as the lack of restraint by corporate executives and boards to engage in excessive risk-taking. The rise in subprime lending between 1997 and 2005 played a crucial role in inflating the housing price bubble. We take a unique dataset of US financial institutions heavily engaged in subprime lending and ask the following research question: Did board configuration play a role in determining whether a financial institution specialized in subprime lending? Research Findings/Insights: We use a matched-pair sample of firms in the financial industry from 1997-2005 with half of the sample specializing in subprime lending and conduct panel data logistic regression analysis. We find that the board configurations of those financial institutions that engaged in subprime lending were significantly different from those that did not. Specifically, subprime lenders had boards that were busier, had less tenure, and were less diverse with respect to gender. Theoretical/Academic Implications: This study uses the group decision making perspective in the context of subprime lending to examine board of director configuration and its influence on decision making processes around the issue of risky subprime lending. Findings show that how boards were configured did influence the decision to specialize in subprime lending. We find robust support for predictions based on the group decision making perspective. Practitioner/Policy Implications: The deterioration of mortgage lending requirements that gave rise to the defaults of so many subprime loans, in retrospect, appears to be something that should have been entirely preventable. By demonstrating that subprime specialists had significant differences in board configuration that impacted group decision making, this study offers guidance to policymakers considering additional regulation and for corporate officers examining corporate governance issues

    Aharanov-Bohm excitons at elevated temperatures in type-II ZnTe/ZnSe quantum dots

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    Optical emission from type-II ZnTe/ZnSe quantum dots demonstrates large and persistent oscillations in both the peak energy and intensity indicating the formation of coherently rotating states. Furthermore, the Aharanov-Bohm (AB) effect is shown to be remarkably robust and persists until 180K. This is at least one order of magnitude greater than the typical temperatures in lithographically defined rings. To our knowledge this is the highest temperature at which the AB effect has been observed in semiconductor structures

    The role of neutrophils in pregnancy, term and preterm labour

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    Neutrophils are surveillance cells, and the first to react and migrate to sites of inflammation and infection following a chemotactic gradient. Neutrophils play a key role in both sterile inflammation and infection, performing a wide variety of effector functions such as degranulation, phagocytosis, ROS production and release of neutrophil extracellular traps (NETs). Healthy term labour requires a sterile pro-inflammatory process, whereas one of the most common causes of spontaneous preterm birth is microbial driven. Peripheral neutrophilia has long been described during pregnancy, and evidence exists demonstrating neutrophils infiltrating the cervix, uterus and foetal membranes during both term and preterm deliveries. Their presence supports a role in tissue remodelling via their effector functions. In this review, we describe the effector functions of neutrophils. We summarise the evidence to support their role in healthy pregnancy and labour and describe their potential contribution to microbial driven preterm birth

    Phase conversion in a weakly first-order quark-hadron transition

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    We investigate the process of phase conversion in a thermally-driven {\it weakly} first-order quark-hadron transition. This scenario is physically appealing even if the nature of this transition in equilibrium proves to be a smooth crossover for vanishing baryonic chemical potential. We construct an effective potential by combining the equation of state obtained within Lattice QCD for the partonic sector with that of a gas of resonances in the hadronic phase, and present numerical results on bubble profiles, nucleation rates and time evolution, including the effects from reheating on the dynamics for different expansion scenarios. Our findings confirm the standard picture of a cosmological first-order transition, in which the process of phase conversion is entirely dominated by nucleation, also in the case of a weakly first-order transition. On the other hand, we show that, even for expansion rates much lower than those expected in high-energy heavy ion collisions, nucleation is very unlikely, indicating that the main mechanism of phase conversion is spinodal decomposition. Our results are compared to those obtained for a strongly first-order transition, as the one provided by the MIT bag model.Comment: 12 pages, 10 figures; v2: 1 reference added, minor modifications, matches published versio

    A Number-Theoretic Error-Correcting Code

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    In this paper we describe a new error-correcting code (ECC) inspired by the Naccache-Stern cryptosystem. While by far less efficient than Turbo codes, the proposed ECC happens to be more efficient than some established ECCs for certain sets of parameters. The new ECC adds an appendix to the message. The appendix is the modular product of small primes representing the message bits. The receiver recomputes the product and detects transmission errors using modular division and lattice reduction

    Levels of genetic polymorphism: marker loci versus quantitative traits

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    Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species

    Effect of quantum interference in the nonlinear conductance of microconstrictions

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    The influence of the interference of electron waves, which were scattered by single impurities, on nonlinear quantum conductance of metallic microconstrictions (as was recently investigated experimentally) is studied theoretically. The dependence of the interference pattern in the conductance G(V)G(V) on the contact diameter and the spatial distribution of impurities is analyzed. It is shown that the amplitude of conductance oscillation is strongly depended on the position of impurities inside the constriction.Comment: 6 pages, 4 figures, To appear in PR
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