525 research outputs found

    One-loop corrections to gaugino (co-)annihilation into quarks in the MSSM

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    We present the full O(αs)\mathcal{O}(\alpha_s) supersymmetric QCD corrections for gaugino annihilation and co-annihilation into light and heavy quarks in the Minimal Supersymmetric Standard Model (MSSM). We demonstrate that these channels are phenomenologically relevant within the so-called phenomenological MSSM. We discuss selected technical details such as the dipole subtraction method in the case of light quarks and the treatment of the bottom quark mass and Yukawa coupling. Numerical results for the (co-)annihilation cross sections and the predicted neutralino relic density are presented. We show that the impact of including the radiative corrections on the cosmologically preferred region of the parameter space is larger than the current experimental uncertainty from Planck data.Comment: 19 pages, 9 figures. Matches version published in Phys.Rev.

    Precision predictions for supersymmetric dark matter

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    The dark matter relic density has been measured by Planck and its predecessors with an accuracy of about 2%. We present theoretical calculations with the numerical program DM@NLO in next-to-leading order SUSY QCD and beyond, which allow to reach this precision for gaugino and squark (co-)annihilations, and use them to scan the phenomenological MSSM for viable regions, applying also low-energy, electroweak and hadron collider constraints.Comment: 6 pages, 1 table, 8 figures, proceedings of ICHEP 201

    Cation selectivity of the presequence translocase channel Tim23 is crucial for efficient protein import.

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    Virtually all mitochondrial matrix proteins and a considerable number of inner membrane proteins carry a positively charged, N-terminal presequence and are imported by the TIM23 complex (presequence translocase) located in the inner mitochondrial membrane. The voltage-regulated Tim23 channel constitutes the actual protein-import pore wide enough to allow the passage of polypeptides with a secondary structure. In this study, we identify amino acids important for the cation selectivity of Tim23. Structure based mutants show that selectivity is provided by highly conserved, pore-lining amino acids. Mutations of these amino acid residues lead to reduced selectivity properties, reduced protein import capacity and they render the Tim23 channel insensitive to substrates. We thus show that the cation selectivity of the Tim23 channel is a key feature for substrate recognition and efficient protein import

    Modeling craniofacial development reveals spatiotemporal constraints on robust patterning of the mandibular arch

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    How does pattern formation occur accurately when confronted with tissue growth and stochastic fluctuations (noise) in gene expression? Dorso-ventral (D-V) patterning of the mandibular arch specifies upper versus lower jaw skeletal elements through a combination of Bone morphogenetic protein (Bmp), Endothelin-1 (Edn1), and Notch signaling, and this system is highly robust. We combine NanoString experiments of early D-V gene expression with live imaging of arch development in zebrafish to construct a computational model of the D-V mandibular patterning network. The model recapitulates published genetic perturbations in arch development. Patterning is most sensitive to changes in Bmp signaling, and the temporal order of gene expression modulates the response of the patterning network to noise. Thus, our integrated systems biology approach reveals non-intuitive features of the complex signaling system crucial for craniofacial development, including novel insights into roles of gene expression timing and stochasticity in signaling and gene regulation

    Characterization of photoresist using speckle fields - a theoretical investigation

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    Gray scale lithography consists of numerous sophisticated fabrication steps making it necessary to characterize the process of substrate structuring. We expose the photoresist with random intensity, i.e. speckle fields instead of conventional specific test patterns and observe their behavior in Fourier plane caused by coherent illumination of this processed substrate

    Numerical models for speckle fields

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    Speckles appear as noisy steady light patterns caused by random phase disturbance of coherently propagating light. Their suppression and use in optical metrology make its simulation and evaluation necessary. This contribution addresses the issue of numerical propagation of speckle distributions

    Iterative phase retrieval: a numerical investigation

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    Estimating the complex amplitude of a coherent optical wavefield is important in many metrology applications. One way to recover the phase information from measured intensity distributions are phase retrieval (PR) algorithms. Here we develop a numerical technique that accurately simulates the propagation of speckle fields and investigate the convergence properties of a PR algorithm

    Propositional Dynamic Logic for Message-Passing Systems

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    We examine a bidirectional propositional dynamic logic (PDL) for finite and infinite message sequence charts (MSCs) extending LTL and TLC-. By this kind of multi-modal logic we can express properties both in the entire future and in the past of an event. Path expressions strengthen the classical until operator of temporal logic. For every formula defining an MSC language, we construct a communicating finite-state machine (CFM) accepting the same language. The CFM obtained has size exponential in the size of the formula. This synthesis problem is solved in full generality, i.e., also for MSCs with unbounded channels. The model checking problem for CFMs and HMSCs turns out to be in PSPACE for existentially bounded MSCs. Finally, we show that, for PDL with intersection, the semantics of a formula cannot be captured by a CFM anymore

    Some considerations when numerically calculating diffraction patterns

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    Numerical calculation of diffraction integrals remains a challenge in modern optics, with applications in digital holography, phase retrieval techniques and wave-front sensing. Two different numerical techniques are compared and the associated sampling rules derived.Zuerst erschienen in: Digital holography and three-dimensional imaging (DH), Tokyo, Japan, May 9, 2011, OSA technical digest (CD), Optical Society of America, 2011, paper DTuC5
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