2,596 research outputs found

    Influence of a magnetic fluxon on the vacuum energy of quantum fields confined by a bag

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    We study the simultaneous influence of boundary conditions and external fields on quantum fluctuations by considering vacuum zero-point energies for quantum fields in the presence of a magnetic fluxon confined by a bag, circular and spherical for bosons and circular for fermions. The Casimir effect is calculated in a generalized cut-off regularization after applying zeta-function techniques to eigenmode sums and using recent techniques about Bessel zeta functions at negative arguments

    Precision tunable resonant microwave cavity

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    A tunable microwave cavity containing ionizable metallic vapor or gases and an apparatus for precisely positioning a microwave coupling tip in the cavity and for precisely adjusting at least one dimension of the cavity are disclosed. With this combined structure, resonance may be achieved with various types of ionizable gases. A coaxial probe extends into a microwave cavity through a tube. One end of the tube is retained in a spherical joint attached in the cavity wall. This allows the coaxial probe to be pivotally rotated. The coaxial probe is slideable within the tube thus allowing the probe to be extended toward or retracted from the center of the cavity

    Galaxy Cluster Mass Estimation from Stacked Spectroscopic Analysis

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    We use simulated galaxy surveys to study: i) how galaxy membership in redMaPPer clusters maps to the underlying halo population, and ii) the accuracy of a mean dynamical cluster mass, Mσ(λ)M_\sigma(\lambda), derived from stacked pairwise spectroscopy of clusters with richness λ\lambda. Using  ⁣130,000\sim\! 130,000 galaxy pairs patterned after the SDSS redMaPPer cluster sample study of Rozo et al. (2015 RMIV), we show that the pairwise velocity PDF of central--satellite pairs with mi<19m_i < 19 in the simulation matches the form seen in RMIV. Through joint membership matching, we deconstruct the main Gaussian velocity component into its halo contributions, finding that the top-ranked halo contributes 60%\sim 60\% of the stacked signal. The halo mass scale inferred by applying the virial scaling of Evrard et al. (2008) to the velocity normalization matches, to within a few percent, the log-mean halo mass derived through galaxy membership matching. We apply this approach, along with mis-centering and galaxy velocity bias corrections, to estimate the log-mean matched halo mass at z=0.2z=0.2 of SDSS redMaPPer clusters. Employing the velocity bias constraints of Guo et al. (2015), we find ln(M200c)λ=ln(M30)+αmln(λ/30)\langle \ln(M_{200c})|\lambda \rangle = \ln(M_{30}) + \alpha_m \ln(\lambda/30) with M30=1.56±0.35×1014MM_{30} = 1.56 \pm 0.35 \times 10^{14} M_\odot and αm=1.31±0.06stat±0.13sys\alpha_m = 1.31 \pm 0.06_{stat} \pm 0.13_{sys}. Systematic uncertainty in the velocity bias of satellite galaxies overwhelmingly dominates the error budget.Comment: 14 pages, 7 figure

    The influence of local field corrections on Thomson scattering in non-ideal two-component plasmas

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    Thomson scattering in non-ideal (collision-dominated) two-component plasmas is calculated accounting for electron-ion collisions as well as electron-electron correlations. This is achieved by using a novel interpolation scheme for the electron-electron response function generalizing the traditional Mermin approach. Also, ions are treated as randomly distributed inert scattering centers. The collision frequency is taken as a dynamic and complex quantity and is calculated from a microscopic quantum-statistical approach. Implications due to different approximations for the electron-electron correlation, i.e. different forms of the OCP local field correction, are discussed

    The Effect of M&A on Employee Performance : An empirical study on post-MBA employee performance in private Norwegian target companies

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    This paper analyses post-M&A employee performance for private Norwegian target companies using accounting data between 2007 and 2016. We have created an algorithm which identifies ownership changes in firms from accounting data. Our model is based on the Cobb-Douglas productivity function to measure firm productivity, and utilizes Propensity Score Matching (PSM) to control for confounding variables. Additionally, we research if the effect of M&A are different based on labor size or sector. As a robustness test we use Nearest Neighbour matching combined with a Difference-In-Difference (DD) analysis to control for possible bias in the PSM analyses. Our results conclude that M&As do not have an effect on employee performance in Norwegian private companies. Furthermore, results indicate a negative effect on firm performance post-M&A. We neither find any reliable differences on employee performance from labor size nor sector. However, we find that the firm performance for the companies with the largest labor force, in the retail industry, and in the remaining sectors are negatively affected post-M&A. The DD analysis mostly support the PSM findings on employee performance and strengthens the validity of our findings. However, we cannot exclude potential confounding of the firm performance outcome variable.nhhma

    August Stramm – YOU. Lovepoems & posthumous love poems:a centenary commemoration ; translation and essay by Susanne Fiessler

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    August Stramm was among the most innovative poets of his time, creating a style of extreme intensity and concentration. His small legacy stands comparison with the international avant-garde. You. Lovepoems celebrates his poetic achievements in memory of his passing in September 1915. The translations bring out the erotic tone of the originals while keeping their flow alive. You aims to convey the “inner experience” captured in the poems, to transfer their “heart” to the listener
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