6,348 research outputs found

    Being Independent is a Great Thing: Subjective Evaluations of Self-Employment and Hierarchy

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    One can be independent, or subject to decisions made by others. This paper empirically tests whether individuals attach an intrinsic value to the institutional difference between independence and hierarchy. Taking self-employment as an important case of independence, it is shown that the self-employed derive more utility from their work than people employed by an organization, irrespective of income gained or hours worked. This is evidence for procedural utility: people do not only value outcomes, but also the conditions and processes leading to these outcomes.procedural utility, institutions, hierarchiy, self-employment, job satisfaction

    Testing multivariate uniformity based on random geometric graphs

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    We present new families of goodness-of-fit tests of uniformity on a full-dimensional set W⊂RdW\subset\R^d based on statistics related to edge lengths of random geometric graphs. Asymptotic normality of these statistics is proven under the null hypothesis as well as under fixed alternatives. The derived tests are consistent and their behaviour for some contiguous alternatives can be controlled. A simulation study suggests that the procedures can compete with or are better than established goodness-of-fit tests. We show with a real data example that the new tests can detect non-uniformity of a small sample data set, where most of the competitors fail.Comment: 36 pages, 2 figure

    Transit Costs and Cost Efficiency: Bootstrapping Nonparametric Frontiers.

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    This paper explores a selection of recently proposed bootstrapping techniques to estimate non-parametric convex (DEA) cost frontiers and efficiency scores for transit firms. Using a sample of Norwegian bus operators, the key results can be summarised as follows: (i) the bias implied by uncorrected cost efficiency measures is numerically important (close to 25%), (ii) the bootstrapped-based test rejects the constant returns to scale hypothesis (iii) explaining patterns of efficiency scores using a two-stage bootstrapping approach detects only one significant covariate, in contrast to earlier results highlighting, e.g., the positive impact of high-powered contract types. Finally, comparing the average inefficiency obtained for the Norwegian data set with an analogous estimate for a smaller French sample illustrates how the estimated differences in average efficiency almost disappear once sample size differences are accounted for.

    Monitoring of the “Energiewende” – energy efficiency indicators for Germany

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    The increasing number of energy and climate targets both at national and international level induces a rising demand for regular monitoring. In this paper, we analyse the possibilities and limits of using energy efficiency indicators as a tool for monitoring these targets. We refer to the energy efficiency targets of the German “Energiewende” and calculate and discuss several energy efficiency indicators for Germany both at the level of the overall economy and the main energy consumption sectors. We make use of the energy efficiency indicator toolbox that we have developed within the ODYSSEE database in recent years and find that there is still a considerable gap to close to achieve the overall energy efficiency targets in Germany by 2020. We also show that progress in energy efficiency slowed down between 2008 and 2012, i.e. compared to the base year of most of the German energy efficiency targets and find that energy efficiency progress in the industrial sector during the last decade has been especially slow. We conclude that improvements in energy efficiency have to speed up considerably in order to achieve the targets for 2020. Although the use of energy efficiency indicators is limited by data constraints and some methodological problems, these indicators give a deep insight into the factors determining energy consumption and can therefore complement the official monitoring process of the German “Energiewende” which only relies on highly aggregated indicators for energy efficiency

    Expert System for the Evaluation of Measurement Uncertainty: Making Use of the Software Tool uncertaintyMANAGERÂź

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    An expert system for the evaluation of the measurement uncertainty is presented. It follows the four-step process established by the Eurachem/CITAC guide QUAM. The expert system provides a considerably better estimate of the overall measurement uncertainty than certain summary approaches used nowadays in most private and public laboratories and in industry. This is demonstrated by an example from the production control in a pharmaceutical lab. In addition, the expert system allows performing the entire process to evaluate the measurement uncertainty much faster than the summary approaches used in industry

    Corporate Management of Highly Dynamic Risks: The Case of Terrorism Insurance in Germany

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    This article extends the theory of corporate risk management to encompass highly dynamic risks. Taking Viscusi'ïżœs (1989) prospective reference from the context of individual decision making and applying it to a corporate context we propose a theory of how corporations process new information. Using unique data on all terrorism insurance policies sold in Germany we find support for this concept of risk-updating by showing that the demand for terrorism insurance is strongly determined by the recent occurrence of terrorist attacks.Corporate Insurance, Risk Management, Terrorism Insurance, Expected Utility, Prospect Theory

    Phenotyping renal leukocyte subsets by four-color flow cytometry: Characterization of chemokine receptor expression

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    To investigate mechanisms of cell-mediated injury in renal inflammatory disease it is critical to determine the surface phenotype of infiltrating renal leukocyte subsets. However, the cell-specific expression of many leukocyte receptors is difficult to characterize in vivo. Here, we report a protocol based on flow cytometry that allows simultaneous characterization of surface receptor expression on different subsets of infiltrating renal leukocytes. The described technique combines an adapted method to prepare single cell suspensions from whole kidneys with subsequent four-color flow cytometry. We recently applied this technique to determine the differential expression of murine chemokine receptors CCR2 and CCR5 on infiltrating renal leukocyte subsets. In this article, we summarize our current findings on the validity of the method as compared with immunohistology and in situ hybridization in two murine models of nonimmune ( obstructive nephropathy) and immune-mediated ( lupus nephritis) inflammatory renal disease. Flow cytometry analysis revealed an accumulation of CCR5-, but not CCR2-positive lymphocytes in inflamed kidneys, compared to the peripheral blood. Particularly renal CD8(+) cells expressed CCR5 (79% in obstructed kidneys, 90% in lupus nephritis). In both models, infiltrating renal macrophages were positive for CCR2 and CCR5. These data corresponded to immunohistological and in situ hybridization results. They demonstrate that flow cytometric analysis of single cell suspensions prepared from inflamed kidneys is a rapid and reliable technique to characterize and quantify surface receptor expression on infiltrating renal leukocyte subsets

    Electron microscopy of high pressure frozen samples: bridging the gap between cellular ultrastructure and atomic resolution

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    Transmission electron microscopy has provided most of what is known about the ultrastructural organization of tissues, cells, and organelles. Due to tremendous advances in crystallography and magnetic resonance imaging, almost any protein can now be modeled at atomic resolution. To fully understand the workings of biological "nanomachines” it is necessary to obtain images of intact macromolecular assemblies in situ. Although the resolution power of electron microscopes is on the atomic scale, in biological samples artifacts introduced by aldehyde fixation, dehydration and staining, but also section thickness reduces it to some nanometers. Cryofixation by high pressure freezing circumvents many of the artifacts since it allows vitrifying biological samples of about 200ÎŒm in thickness and immobilizes complex macromolecular assemblies in their native state in situ. To exploit the perfect structural preservation of frozen hydrated sections, sophisticated instruments are needed, e.g., high voltage electron microscopes equipped with precise goniometers that work at low temperature and digital cameras of high sensitivity and pixel number. With them, it is possible to generate high resolution tomograms, i.e., 3D views of subcellular structures. This review describes theory and applications of the high pressure cryofixation methodology and compares its results with those of conventional procedures. Moreover, recent findings will be discussed showing that molecular models of proteins can be fitted into depicted organellar ultrastructure of images of frozen hydrated sections. High pressure freezing of tissue is the base which may lead to precise models of macromolecular assemblies in situ, and thus to a better understanding of the function of complex cellular structure
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