1,029 research outputs found

    An Empirical Framework for Matching with Imperfectly Transferable Utility

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    We introduce an empirical framework for models of matching with imperfectly transferable utility and unobserved heterogeneity in tastes. Our framework includes as special cases the classic fully- and non-transferable utility models, collective models, and settings with taxes on transfers, deadweight losses, and risk aversion. We characterize equilibrium and conditions for identification, and derive comparative statics

    Quantitative modeling of laser speckle imaging

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    We have analyzed the image formation and dynamic properties in laser speckle imaging (LSI) both experimentally and with Monte-Carlo simulation. We show for the case of a liquid inclusion that the spatial resolution and the signal itself are both significantly affected by scattering from the turbid environment. Multiple scattering leads to blurring of the dynamic inhomogeneity as detected by LSI. The presence of a non-fluctuating component of scattered light results in the significant increase in the measured image contrast and complicates the estimation of the relaxation time. We present a refined processing scheme that allows a correct estimation of the relaxation time from LSI data.Comment: submitted to Optics Letter

    Interaction of reactive gases with platinum aerosol particles at room temperature: effects on morphology and surface properties

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    Nanoparticles produced in technical aerosol processes exhibit often dendritic structures, composed of primary particles. Surprisingly, a small but consistent discrepancy was observed between the results of common aggregation models and in situ measurements of structural parameters, such as fractal dimension or mass-mobility exponent. A phenomenon which has received little attention so far is the interaction of agglomerates with admixed gases, which might be responsible for this discrepancy. In this work, we present an analytical series, which underlines the agglomerate morphology depending on the reducing or oxidizing nature of a carrier gas for platinum particles. When hydrogen is added to openly structured particles, as investigated by tandem differential mobility analysis (DMA) and transmission electron microscopy (TEM) analysis, Pt particles compact already at room temperature, resulting in an increased fractal dimension. Aerosol Photoemission Spectroscopy (APES) was also able to demonstrate the interaction of a gas with a nanoscaled platinum surface, resulting in a changed sintering behavior for reducing and oxidizing atmospheres in comparison to nitrogen. The main message of this work is about the structural change of particles exposed to a new environment after complete particle formation. We suspect significant implications for the interpretation of agglomerate formation, as many aerosol processes involve reactive gases or slightly contaminated gases in terms of trace amounts of unintended species

    Influence of spray drying parameters on the formation of β-phase poly(vinylidene fluoride)

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    A simple one-step spraying method to produce poly(vinylidene fluoride) (PVDF) in the desired conformation is presented. The content of the piezoelectric β-phase is measured at different spray drying conditions and during electrospray. The influence of a strong electrical field and charges on the droplet are investigated separately from the electrospray setup with a pneumatic atomizer. For this purpose, the electric field is integrated into a pneumatic atomization process by a plate capacitor and the charge of the droplets by corona discharge. To investigate the drying properties, the drying temperature and the flow rate of dry air are examined. The presented process offers the possibility to deposit PVDF films or to produce PVDF powders, in their piezoelectric β- and γ-phases or in the nonpolar α-phase

    Influence of the impaction angle on the triboelectric charging of aerosol nanoparticles

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    A low pressure impactor is used to measure triboelectric charging behavior of metallic nanoparticles. Ag nanoparticles, produced by spark discharge, were impacted onto Pt sputtered targets. The influence of the impaction angle and impaction velocity on the triboelectric charging was investigated. While for perpendicular impaction the charge transfer behavior of previous work was confirmed, the oblique impaction revealed new phenomena. Additional charge transfer was observable, which increases with obliqueness. The possibility of mass transfer between particle and target due to the high-energy collisions was also investigated. SEM characterization and Auger spectroscopy indicate mass transfer from the particle to the target surface

    Der soziologische Kulturbegriff

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    Matching Function Equilibria with Partial Assignment: Existence, Uniqueness and Estimation

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    In this paper, we argue that models coming from a variety of fields share a common structure that we call matching function equilibria with partial assignment. This structure revolves around an aggregate matching function and a system of nonlinear equations. This encompasses search and matching models, matching models with transferable, non-transferable and imperfectly transferable utility, and matching with peer effects. We provide a proof of existence and uniqueness of an equilibrium as well as an efficient algorithm to compute it. We show how to estimate parametric versions of these models by maximum likelihood. We also propose an approach to construct counterfactuals without estimating the matching functions for a subclass of models. We illustrate our estimation approach by analyzing the impact of the elimination of the Social Security Student Benefit Program in 1982 on the marriage market in the United States

    Joint crisis plans and psychiatric advance directives in German psychiatric practice

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    This study explores the attitude of German psychiatrists in leading positions towards joint crisis plans and psychiatric advance directives. This topic was examined by contacting 473 medical directors of German psychiatric hospitals and departments. They were asked to complete a questionnaire developed by us. That form contained questions about the incidence and acceptance of joint crisis plans and psychiatric advance directives and previous experiences with them. 108 medical directors of psychiatric hospitals and departments responded (response rate: 22.8%). Their answers demonstrate that in their hospitals these documents are rarely used. Among the respondents, joint crisis plans are more accepted than psychiatric advance directives. There is a certain uncertainty when dealing with these instruments. Our main conclusion is that German psychiatry needs an intensified discussion on the use of instruments for patients to constitute procedures for future critical psychiatric events. For this purpose it will be helpful to collect more empirical data. Furthermore, the proposal of joint crisis plans in psychiatric hospitals and departments should be discussed as well as the possibility of consulting an expert during the preparation of a psychiatric advance directive

    Joint crisis plans and psychiatric advance directives in German psychiatric practice

    Get PDF
    This study explores the attitude of German psychiatrists in leading positions towards joint crisis plans and psychiatric advance directives. This topic was examined by contacting 473 medical directors of German psychiatric hospitals and departments. They were asked to complete a questionnaire developed by us. That form contained questions about the incidence and acceptance of joint crisis plans and psychiatric advance directives and previous experiences with them. 108 medical directors of psychiatric hospitals and departments responded (response rate: 22.8%). Their answers demonstrate that in their hospitals these documents are rarely used. Among the respondents, joint crisis plans are more accepted than psychiatric advance directives. There is a certain uncertainty when dealing with these instruments. Our main conclusion is that German psychiatry needs an intensified discussion on the use of instruments for patients to constitute procedures for future critical psychiatric events. For this purpose it will be helpful to collect more empirical data. Furthermore, the proposal of joint crisis plans in psychiatric hospitals and departments should be discussed as well as the possibility of consulting an expert during the preparation of a psychiatric advance directive
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