6,019 research outputs found

    The Pharmacological Potential of Mushrooms

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    This review describes pharmacologically active compounds from mushrooms. Compounds and complex substances with antimicrobial, antiviral, antitumor, antiallergic, immunomodulating, anti-inflammatory, antiatherogenic, hypoglycemic, hepatoprotective and central activities are covered, focusing on the review of recent literature. The production of mushrooms or mushroom compounds is discussed briefly

    Wrinkling prediction in sheet metal forming and experimental verification

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    In this work, the analysis of Hutchinson and Neale is used for wrinkling prediction. Under a number of assumptions, limitations and simplifications a wrinkling criterion with some restrictive applicability, is obtained. Unfortunately, Hutchinson analysis is limited to regions of the sheet that are free of any contact. When contact is taken into account the problem is further complicated. Consequently, a local indicator based on the change of curvatures under compressive stresses is developed. Both wrinkling indicators are used to drive the adaptive mesh refinement in order to be able to accurately spot wrinkling. The numerical results will be compared to those obtained through experimental testing. A number of hemispherical product samples have been used with various blank holder forces and drawn to different depths to capture the onset of wrinkling, its mode and locatio

    Hierarchies from D-brane instantons in globally defined Calabi-Yau Orientifolds

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    We construct the first globally consistent semi-realistic Type I string vacua on an elliptically fibered manifold where the zero modes of the Euclidean D1-instanton sector allow for the generation of non-perturbative Majorana masses of an intermediate scale. In another class of global models, a D1-brane instanton can generate a Polonyi-type superpotential breaking supersymmetry at an exponentially suppressed scale.Comment: 4 pages, 4 tables, uses revtex; v2: Discussion of instanton curves improved, typos fixed, references added; v3: version published in PR

    Corporate Responses to Climate Change and Financial Performance: The Impact of Climate Policy

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    This paper examines the relationship between corporate activities to address climate change and stock performance. By separately analyzing the US and European stock markets for different sub-periods, we highlight the impact of the underlying climate policy regime. Methodologically, we compare risk-adjusted returns of stock portfolios comprising corporations that differ in their responses to climate change. In this respect, we apply the flexible Carhart fourfactor model besides the restricted one-factor model based on the Capital Asset Pricing Model (CAPM). While our portfolio analysis shows negative relationships over the entire observation period from 2001 to 2006, we find that a trading strategy, which bought stocks of corporations with a higher level of responses to climate change and sold stocks of corporations with a lower level, led to negative abnormal returns in regions and periods with less ambitious climate policy, but to positive abnormal returns in regions and periods with stringent climate policy.Climate change, Climate policy, Corporate environmental performance, Financial performance, Portfolio analysis, Asset pricing models

    Impact of tax rate cut cum base broadening reforms on heterogeneous firms: Learning from the German tax reform 2008

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    The German corporate tax reform of 2008 has brought about important cuts in corporate tax rates, which were at the same time accompanied by significant changes in the determination of the tax base for both major German corporate taxes - corporate income tax and trade tax. The reform followed the distinct and internationally prevalent pattern of tax rate cut cum base broadening. Its implications are thus not unique to Germany. Especially in view of the current economic crisis, questions on the distribution of the tax burden among firms of different characteristics have arisen and still remain at the heart of the academic and political debate in Germany and other countries. In this paper we present a new corporate microsimulation model, ZEW TaxCoMM, which allows for the coherent micro-based analysis of revenue implications of tax reforms and the distribution of tax consequences among heterogeneous firms. The model processes firm-level financial accounting input data and derives the firm specific tax base and tax due endogenously in accordance with the tax code. To smooth out distortions between the sample and the population of German corporations, the sample is extrapolated on the basis of the corporate income tax statistic. The simulation results show inter alia that the average annual relief as measured by the average decline in the effective tax burden on cash flow amounts to 2.8 percentage points for large corporations and to 6 percentage points for small corporations. Furthermore, the results illustrate that firms with low profitability, high debt ratio and high capital intensity benefit least from the reform. As to tax revenues, the reform induced decrease amounts to 9.8 billion and the trade tax gains fiscally in importance. --Tax reform,microsimulation,tax policy evaluation

    Utilizing weak pump depletion to stabilize squeezed vacuum states

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    We propose and demonstrate a pump-phase locking technique that makes use of weak pump depletion (WPD) - an unavoidable effect that is usually neglected - in a sub-threshold optical parametric oscillator (OPO). We show that the phase difference between seed and pump beam is imprinted on both light fields by the non-linear interaction in the crystal and can be read out without disturbing the squeezed output. Our new locking technique allows for the first experimental realization of a pump-phase lock by reading out the pre-existing phase information in the pump field. There is no degradation of the detected squeezed states required to implement this scheme.Comment: 11 pages, 7 figure
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