18,875 research outputs found

    The Behavioral Firm and Its Internal Game: Evolutionary Dynamics of Decision Making

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    In this paper the firm is analyzed and modeled as a set of different subcoalitions (agents) each with their own objectives. It examines how the goals can be conflicting and in turn how this influences the payoff structure of the subcoalitions given that they follow 'simple' decision rules, i.e. rules of thumb. This implies that the subcoalitions act in aboundedly rational way. To see how these decision making procedures evolve we make use of an (evolutionary) dynamic game theoretical framework. Consequently, the main aim is to address the issue of modeling the dynamic and adaptive nature of the subcoalitions

    The effect of core polarization on longitudinal form factors in 10^{10}B

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    Electron scattering Coulomb form factors for the single-particle quadrupole transitions in pp-shell 10^{10}B nucleus have been studied. Core polarization effects are included through a microscopic theory that includes excitations from the core orbits up to higher orbits with 2\hbarω\omega excitations. The modified surface delta interaction (MSDI) is employed as a residual interaction. The effect of core polarization is found essential in both the transition strengths and momentum transfer dependence of form factors, and gives a remarkably good agreement with the measured data with no adjustable parameters.Comment: 4 pages, 5 figure

    Laboratory mid-IR spectra of equilibrated and igneous meteorites. Searching for observables of planetesimal debris

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    Meteorites contain minerals from Solar System asteroids with different properties (like size, presence of water, core formation). We provide new mid-IR transmission spectra of powdered meteorites to obtain templates of how mid-IR spectra of asteroidal debris would look like. This is essential for interpreting mid-IR spectra of past and future space observatories, like the James Webb Space Telescope. We show that the transmission spectra of wet and dry chondrites, carbonaceous and ordinary chondrites and achondrite and chondrite meteorites are distinctly different in a way one can distinguish in astronomical mid-IR spectra. The two observables that spectroscopically separate the different meteorites groups (and thus the different types of parent bodies) are the pyroxene-olivine feature strength ratio and the peak shift of the olivine spectral features due to an increase in the iron concentration of the olivine

    Evidence for precession of the isolated neutron star RX J0720.4-3125

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    The XMM-Newton spectra of the isolated neutron star RX J0720.4-3125 obtained over 4.5 years can be described by sinusoidal variations in the inferred blackbody temperature, the size of the emitting area and the depth of the absorption line with a period of 7.1 +/- 0.5 years, which we suggest to be the precession period of the neutron star. Precession of a neutron star with two hot spots of different temperature and size, probably not located exactly in antipodal positions, may account for the variations in the X-ray spectra, changes in the pulsed fraction, shape of the light curve and the phase-lag between soft and hard energy bands observed from RX J0720.4-3125. An independent sinusoidal fit to published and new pulse timing residuals from a coherent analysis covering ~12 years yields a consistent period of 7.7 +/- 0.6 years supporting the precession model.Comment: Accepted for publication in A&A Letters, 5 pages, 5 figure

    Towards a Soil Information System with quantified accuracy : a prototype for mapping continuous soil properties

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    This report describes the potential and functionality of software for spatial analysis, prediction and stochastic simulation of continuous soil properties using data from the Dutch Soil Information System (BIS). A geostatistical framework and R codes were developed. The geostatistical model of a soil property has a deterministic component representing the mean value within a soil category, and a stochastic component of standardized residuals. The standardized residuals are interpolated or simulated based on the simple kriging system. The software was tested in four case studies: exchangeable soil pH, clay content, organic matter content and Mean Spring Water table depth (MSW). It is concluded that the geostatistical framework and R codes developed in this study enable to predict values of continuous soil properties spatially, and to quantify the inaccuracy of these predictions. The inaccuracy of a spatial prediction at a certain location is quantified by the kriging variance, which can be interpreted as an indication of the uncertainty about the true value

    Patterns of Adherence to Oral Hypoglycemic Agents: Patterns, Correlates, and Outcomes

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    Despite the development of effective pharmacological therapy to prevent both macrovascular and microvascular complications and adverse events, diabetes control remains sub-optimal. Poor adherence to recommended regimens is a causal factor in preventable morbidity and mortality in diabetic patients. Sub-groups of patients with differing longitudinal profiles of adherence may yield differing treatment outcomes. Identifying characteristics associated with longitudinal profiles can potentially alert clinicians to patients at risk for poor clinical outcomes allowing for early intervention and follow-up. Furthermore, few studies have examined the role of adherence improvements as a mediator of intervention effect on glycemic control. In this work we sought to identify patterns, correlates and outcomes of adherence to oral hypoglycemic agents. We also assessed whether adherence improvements mediated a brief interventions effect on glycemic control. Longitudinal analysis via growth curve mixture modeling was carried out to classify 180 patients who participated in an adherence intervention according to patterns of adherence to oral hypoglycemic agents across 12 weeks. Adherence was assessed using the Medication Event Monitoring System. Hemoglobin A1c assays were used to measure glycemic control as the clinical outcome. Individual patient residential data was geo-coded at the tract level. Three patterns of adherence to oral hypoglycemic agents were identified: adherent, increasing adherence, and nonadherent. Both individual and neighborhood level factors were identified that were associated with patterns of adherence. Patients with an increasing adherence pattern were more likely to have a Hemoglobin A1c (HbA1c) \u3c 7% (adjusted odds ratio = 14.52, 95% CI [2.54, 82.99]) at 12 weeks in comparison with patients with the nonadherent pattern. Across the whole sample, longitudinal adherence profiles mediated 35.2 % (13.2, 81.0 %) of the effect of a brief adherence intervention on glycemic control [from odds ratio (OR) = 8.48, 95 % confidence interval (CI) (3.24, 22.2) to 4.00, 95 % CI (1.34, 11.93)]. These findings imply that the identification of patients with type 2 diabetes at risk of nonadherence is important for clinical prognosis and the development and delivery of interventions
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