149 research outputs found

    Ohne Sozialtheorie keine Gewaltanalyse: Rezension zu "Gewaltgedächtnisse - Analysen zur Präsenz vergangener Gewalt" von Nina Leonhard und Oliver Dimbath (Hg.)

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    Nina Leonhard, Oliver Dimbath (Hrsg.): Gewaltgedächtnisse - Analysen zur Präsenz vergangener Gewalt. Wiesbaden: VS Verlag für Sozialwissenschaften 2021. 978-3-658-32141-

    Near- and mid-infrared supercontinuum sources with MHz repetition rates

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    Examining the Interaction Between Leadership Style and Organizational Justice and its Effect on Organizational Commitment, Job Satisfaction, and Work Stress

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    This thesis examines the constructs of organizational commitment, job satisfaction, and work stress, and the extent to which they are affected by perceptions of organizational justice and leadership styles. Much of the literature related to these topics focuses on exploring the relationship between either justice and commitment or leadership and commitment, with very little research investigating the way that justice and leadership combine to affect outcome variables such as commitment, satisfaction, and stress. This study reviewed the literature that details these topics in order to facilitate the understanding necessary to then focus on the relationship between commitment, organizational justice, and leadership style, as well as job satisfaction and work stress. It is important to understand how these three concepts affect one another, as increasing employee commitment is a goal of many, if not all organizations, and understanding how to better influence and facilitate it could be very valuable information

    Linear refractive index and absorption measurements of nonlinear optical liquids in the visible and near-infrared spectral region

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    Liquid-filled photonic crystal fibers and optofluidic devices require infiltration with a variety of liquids whose linear optical properties are still not well known over a broad spectral range, particularly in the near infrared. Hence, dispersion and absorption properties in the visible and near-infrared wavelength region have been determined for distilled water, heavy water, chloroform, carbon tetrachloride, toluene, ethanol, carbon disulfide, and nitrobenzene at a temperature of 20 °C. For the refractive index measurement a standard Abbe refractometer in combination with a white light laser and a technique to calculate correction terms to compensate for the dispersion of the glass prism has been used. New refractive index data and derived dispersion formulas between a wavelength of 500 nm and 1600 nm are presented in good agreement with sparsely existing reference data in this wavelength range. The absorption coefficient has been deduced from the difference of the losses of several identically prepared liquid filled glass cells or tubes of different lengths. We present absorption data in the wavelength region between 500 nm and 1750 nm

    Wideband tuning of four-wave mixing in solid-core liquid-filled photonic crystal fibers

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    We present an experimental study of parametric four-wave mixing generation in photonic crystal fibers that have been infiltrated with ethanol. A silica photonic crystal fiber was designed to have the proper dispersion properties after ethanol infiltration for the generation of widely spaced four-wave mixing (FWM) bands under 1064 nm pumping. We demonstrate that the FWM bands can be tuned in a wide wavelength range through the thermo-optic effect. Band shifts of 175 and over 500 nm for the signal and idler bands, respectively, are reported. The reported results can be of interest in many applications, such as CARS microscopy

    Structure of the complex of cytochrome c with cardiolipin in non-polar environment

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    The complex of mitochondrial protein cytochrome c (CytC) with anionic phospholipid cardiolipin (CL) plays a crucial role in the initiation of apoptosis by catalyzing lipid peroxidation in mitochondrial membranes. In our previous papers, we found that CytC and CL mixed in millimolar concentrations form a sediment showing microcrystals composed of nanospheres (Cyt-CL) of 11–12 and 8 nm in diameter. The hypothesis was proposed that Cyt-CL, having hydrophobic shell, may appear inside the membrane lipid bilayer in mitochondria and peroxidase membrane phospholipids so initiating the apoptotic cascade. In this work, Cyt-CL complex dissolved in chloroform or hexane was investigated as a model of the complex in mitochondrial membranes. We used dynamic light scattering method to measure the size of the particles. The analysis of particles size distribution of Cyt-CL in chloroform allows to reveal three dominant diameters of 12.1 ± 1.4, 7.8 ± 1.0, and 4.7 ± 0.7 nm. The first two values are closed to those, earlier obtained with small-angle X-ray scattering method in Cyt-CL microcrystals, 11.1 ± 1.0 and 8.0 ± 0.7 nm. CL extracted in chloroform-methanol forms a real solution of particles with diameter of 0.7 ± 0.1 nm. In methanol-water phase, CL and CL + CytC mixture form particles of 83.7 ± 9.8 and 71.3 ± 11.6 nm, respectively. Apparently, cardiolipin in 50% methanol forms single-layer liposomes regardless of the presence of CytC in the medium. Partial unfolding of CytC in the complex was evidenced by (a) appearance of fluorescence of tyrosine and tryptophan residues and (b) disappearance of the absorption band at 699 nm due to breakdown of heme iron – methionine bond > F⋯S(Met80). In hydrophobic solvent Cyt-CL exhibited quasi-lipoperoxidase and lipoxygenase activity as was shown in kinetic measurements of chemiluminescence enhanced by coumarin C-525, a selective sensitizer of chemiluminescence, associated with reactions of lipid peroxyl radicals. Our data in this model system do not contradict the hypothesis (Vladimirov, Y.A. et al. Biochemistry (Mosc) 78, 1086–1097) that nanospheres of Cyt-CL complex, embedded into the lipid phase of mitochondrial membrane, catalyze lipid peroxidation, thereby initiating apoptosis

    Optimistic Planning in Markov Decision Processes Using a Generative Model

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    International audienceWe consider the problem of online planning in a Markov decision process with discounted rewards for any given initial state. We consider the PAC sample com-plexity problem of computing, with probability 1−δ, an -optimal action using the smallest possible number of calls to the generative model (which provides reward and next-state samples). We design an algorithm, called StOP (for Stochastic-Optimistic Planning), based on the "optimism in the face of uncertainty" princi-ple. StOP can be used in the general setting, requires only a generative model, and enjoys a complexity bound that only depends on the local structure of the MDP

    Aggregating Optimistic Planning Trees for Solving Markov Decision Processes

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    peer reviewedThis paper addresses the problem of online planning in Markov decision processes using a randomized simulator, under a budget constraint. We propose a new algorithm which is based on the construction of a forest of planning trees, where each tree corresponds to a random realization of the stochastic environment. The trees are constructed using a “safe” optimistic planning strategy combining the optimistic principle (in order to explore the most promising part of the search space first) with a safety principle (which guarantees a certain amount of uniform exploration). In the decision-making step of the algorithm, the individual trees are aggregated and an immediate action is recommended. We provide a finite-sample analysis and discuss the trade-off between the principles of optimism and safety. We also report numerical results on a benchmark problem. Our algorithm performs as well as state-of-the-art optimistic planning algorithms, and better than a related algorithm which additionally assumes the knowledge of all transition distributions
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