1,866 research outputs found

    The subdwarf B star SB 290 - A fast rotator on the extreme horizontal branch

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    Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very thin hydrogen envelopes. In order to form an sdB, the progenitor has to lose almost all of its hydrogen envelope right at the tip of the red giant branch. In close binary systems, mass transfer to the companion provides the extraordinary mass loss required for their formation. However, apparently single sdBs exist as well and their formation is unclear since decades. The merger of helium white dwarfs leading to an ignition of core helium-burning or the merger of a helium core and a low mass star during the common envelope phase have been proposed. Here we report the discovery of SB 290 as the first apparently single fast rotating sdB star located on the extreme horizontal branch indicating that those stars may form from mergers.Comment: 5 pages, 4 figures, A&A letters, accepte

    Documentation of the GLAS fourth order general circulation model. Volume 1: Model documentation

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    The volume 1, of a 3 volume technical memoranda which contains a documentation of the GLAS Fourth Order General Circulation Model is presented. Volume 1 contains the documentation, description of the stratospheric/tropospheric extension, user's guide, climatological boundary data, and some climate simulation studies

    Deuteron Spin Structure Functions at Small Bjorken-x

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    We investigate polarized deuteron structure functions at small values of the Bjorken variable, x < 0.1. In this region contributions from the coherent interaction of diffractively excited hadronic states with both nucleons become important. A proper treatment of this process requires an extension of the Glauber-Gribov multiple scattering theory to include spin degrees of freedom. In the kinematic domain of current fixed target experiments we observe that shadowing effects in g_1d are approximately twice as large as for the unpolarized structure function F_2d. Furthermore at x < 0.1 the tensor structure function b_1 is found to receive significant contributions from coherent double scattering.Comment: 30 pages, Revtex, include discussion on t-dependence of diffractive production processes, to appear in Phys. Rev.

    Deubiquitinases: Novel Therapeutic Targets in Immune Surveillance?

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    Inflammation is a protective response of the organism to tissue injury or infection. It occurs when the immune system recognizes Pathogen-Associated Molecular Patterns (PAMPs) or Damage-Associated Molecular Pattern (DAMPs) through the activation of Pattern Recognition Receptors. This initiates a variety of signalling events that conclude in the upregulation of proinflammatory molecules, which initiate an appropriate immune response. This response is tightly regulated since any aberrant activation of immune responses would have severe pathological consequences such as sepsis or chronic inflammatory and autoimmune diseases. Accumulative evidence shows that the ubiquitin system, and in particular ubiquitin-specific isopeptidases also known as deubiquitinases (DUBs), plays crucial roles in the control of these immune pathways. In this review we will give an up-to-date overview on the role of DUBs in the NF-ÎşB pathway and inflammasome activation, two intrinsically related events triggered by activation of the membrane TLRs as well as the cytosolic NOD and NLR receptors. Modulation of DUB activity by small molecules has been proposed as a way to control dysregulation or overactivation of these key players of the inflammatory response. We will also discuss the advances and challenges of a potential use of DUBs as therapeutic targets in inflammatory pathologies

    Documentation of the GLAS fourth order general calculation model. Volume 3: Vectorized code for the Cyber 205

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    Volume 3 of a 3-volume technical memoranda which contains documentation of the GLAS fourth order genera circulation model is presented. The volume contains the CYBER 205 scalar and vector codes of the model, list of variables, and cross references. A dictionary of FORTRAN variables used in the Scalar Version, and listings of the FORTRAN Code compiled with the C-option, are included. Cross reference maps of local variables are included for each subroutine

    Documentation of the GLAS fourth order general circulation model. Volume 2: Scalar code

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    Volume 2, of a 3 volume technical memoranda contains a detailed documentation of the GLAS fourth order general circulation model. Volume 2 contains the CYBER 205 scalar and vector codes of the model, list of variables, and cross references. A variable name dictionary for the scalar code, and code listings are outlined

    MODELLING AND PROGNOSIS OF COMPETITIVE PERFORMANCES IN ELITE SWIMMING

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    The study demonstrates that the performance of an elite female swimmer in the finals of the 200 m backstroke at the Olympic Games 2000 in Sydney can be predicted by means of the nonlinear mathematical method of a neural back-propagation network. The analysis included the performance output data of 19 competitions prior to the Olympics within a time period of 95 successive weeks and the training input data of the last four weeks prior to each competition. The training data were divided into two phases: (1) a two-week taper cycle, and (2) an earlier two-week high load cycle. The trained neural network was not only able to model the 19 competitive performances, but also to predict the performance in the semi final of the Olympic Games in Sydney on the basis of the two sets of training data during the preparation before that specific competition

    TIME-VARIANT SPECTRAL ANALYSIS OF SURFACE EMG SIGNALS – EXEMPLARILY SHOWN FOR ARCHERY

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    To analyse the spectral density of electromyographic (EMG) signals Fourier transforms are commonly used. The prerequisite of this transform is that the analysed signal is stationary. Generally, this can not be assumed for the electromyograms of muscle contractions of human movement. A new method to analyse non-stationary biological signals is the time-variant spectral analysis. The aim of this paper is to use the timevariant spectral analysis in a realistic sport application to show connections of the athlete’s level and the spectral density of the EMG. Five top-level archers participated in the study. The results suggest, that a higher level of performance generally corresponds to lower median-frequencies and a smaller variability of the median-frequencies of the EMG-signals

    MOTION OF THE BOW DURING AIMING AND RELEASING THE SHOT

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    The range of motion of a recurve bow during aiming and releasing the shot is very small. Thus on-target-trajectories are used. To measure the on-target-trajectories of bows a system originally designed for gun shooting was modified. The system can be fitted onto the archer’s personal bow. 15 highly skilled archers of the German National Teams of women and men participated in the study. Two intraindividual typical strategies of aiming were found: 11 archers try to hold the aim on sight for at least 2 seconds whereas 4 archers tend to “slide” on the target and release the shot at once when the target is on sight. For 14 of 15 archers the “hold boxes” disclose an asymmetry in aiming: The horizontal magnitude of the hold box is larger than the vertical dimension. From release to when the arrow leaves the string, the right handed archers tend to move to the left and the left handed archers tend to move right
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