13,763 research outputs found

    Comorbidities of patients in tiotropium clinical trials : comparison with observational studies of patients with chronic obstructive pulmonary disease

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    Acknowledgments The authors are fully responsible for all content and editorial decisions made, were involved at all stages of manuscript development, and have approved the final version for publication. Editorial assistance, supported financially by Boehringer Ingelheim and Pfizer, was provided by Godfrey Lisk of PAREXEL International during the preparation of this manuscript. This work is published by Dove Medical Press Limited, and licensed under Creative Commons Attribution - Non Commercial (unported, v3.0) License. The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. Permissions beyond the scope of the License are administered by Dove Medical Press Limited.Peer reviewedPublisher PD

    Unitarisation of EFT Amplitudes for Dark Matter Searches at the LHC

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    We propose a new approach to the LHC dark matter search analysis within the effective field theory (EFT) framework by utilising the K-matrix unitarisation formalism. This approach provides a reasonable estimate of the dark matter production cross section at high energies, and hence allows reliable bounds to be placed on the cut-off scale of relevant operators without running into the problem of perturbative unitarity violation. We exemplify this procedure for the effective operator D5 in monojet dark matter searches in the collinear approximation. We compare our bounds to those obtained using the truncation method and identify a parameter region where the unitarisation prescription leads to more stringent bounds.Comment: 20 pages, 7 figures. References added and minor corrections made to match published versio

    Exact diagonalization study of the tunable edge magnetism in graphene

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    The tunable magnetism at graphene edges with lengths of up to 48 unit cells is analyzed by an exact diagonalization technique. For this we use a generalized interacting one-dimensional model which can be tuned continuously from a limit describing graphene zigzag edge states with a ferromagnetic phase, to a limit equivalent to a Hubbard chain, which does not allow ferromagnetism. This analysis sheds light onto the question why the edge states have a ferromagnetic ground state, while a usual one-dimensional metal does not. Essentially we find that there are two important features of edge states: (a) umklapp processes are completely forbidden for edge states; this allows a spin-polarized ground state. (b) the strong momentum dependence of the effective interaction vertex for edge states gives rise to a regime of partial spin-polarization and a second order phase transition between a standard paramagnetic Luttinger liquid and ferromagnetic Luttinger liquid.Comment: 11 pages, 8 figure

    Slow Synaptic Inhibition in Nucleus HVc of the Adult Zebra Finch

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    Nervous systems process information over a broad range of time scales and thus need corresponding cellular mechanisms spanning that range. In the avian song system, long integration times are likely necessary to process auditory feedback of the bird’s own vocalizations. For example, in nucleus HVc, a center that contains both auditory and premotor neurons and that is thought to act as a gateway for auditory information into the song system, slow inhibitory mechanisms appear to play an important role in the processing of auditory information. These long-lasting processes include inhibitory potentials thought to shape auditory selectivity and a vocalization-induced inhibition of auditory responses lasting several seconds. To investigate the possible cellular mechanisms of these long-lasting inhibitory processes, we have made intracellular recordings from HVc neurons in slices of adult zebra finch brains and have stimulated extracellularly within HVc. A brief, high-frequency train of stimuli (50 pulses at 100 Hz) could elicit a hyperpolarizing response that lasted 2–20 sec. The slow hyperpolarization (SH) could still be elicited in the presence of glutamate receptor blockers, suggesting that it does not require polysynaptic excitation. Three major components contribute to this activity-induced SH: a long-lasting GABA_B receptor-mediated IPSP, a slow afterhyperpolarization requiring action potentials but not CaÂČâș influx, and a long-lasting IPSP, the neurotransmitter and receptor of which remain unidentified. These three slow hyperpolarizing events are well placed to contribute to the observed inhibition of HVc neurons after singing and could shape auditory feedback during song learning

    Interstitial stem cells in Hydra

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    Ni-MH storage test and cycle life test

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    Gates Aerospace Batteries is conducting two long term test programs to fully characterize the NiMH cell technology for aerospace applications. The first program analyzes the effects of long term storage upon cell performance. The second program analyzes cycle life testing and preliminary production lot testing. This paper summarizes these approaches to testing the NiMH couple and culminates with initial storage and testing recommendations. Long term storage presents challenges to deter the adverse condition of capacity fade in NiMH cells. Elevated but stabilized pressures and elevated but stabilized end-of-charge voltages also appear to be a characteristic phenomenon of long term storage modes. However, the performance degradation is dependent upon specific characteristics of the metal-hydride alloy. To date, there is no objective evidence with which to recommend the proper method for storage and handling of NiMH cells upon shipment. This is particularly critical due to limited data points that indicate open circuit storage at room temperature for 60 to 90 days will result in irrecoverable capacity loss. Accordingly a test plan was developed to determine what method of mid-term to long-term storage will prevent irrecoverable capacity loss. The explicit assumption is that trickle charging at some rate above the self-discharge rate will prevent the irreversible chemical changes to the negative electrode that result in the irrecoverable capacity loss. Another premise is that lower storage temperatures, typically 0 C for aerospace customers, will impede any negative chemical reactions. Three different trickle charge rates are expected to yield a fairly flat response with respect to recoverable capacity versus baseline cells in two different modes of open circuit. Specific attributes monitored include: end-of-charge voltage, end-of-charge pressure, mid-point discharge voltage, capacity, and end-of-discharge pressure. Cycle life testing and preliminary production lot testing continue to dominate the overall technology development effort at GAB. The cell life test program reflects continuing improvements in baseline cell designs. Performance improvements include lower and more stable charge voltages and pressures. The continuing review of production lot testing assures conformance to the design criteria and expectations. This is especially critical during this period of transferring technology from research and development status to production

    Morphology and function of Neandertal and modern human ear ossicles.

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    The diminutive middle ear ossicles (malleus, incus, stapes) housed in the tympanic cavity of the temporal bone play an important role in audition. The few known ossicles of Neandertals are distinctly different from those of anatomically modern humans (AMHs), despite the close relationship between both human species. Although not mutually exclusive, these differences may affect hearing capacity or could reflect covariation with the surrounding temporal bone. Until now, detailed comparisons were hampered by the small sample of Neandertal ossicles and the unavailability of methods combining analyses of ossicles with surrounding structures. Here, we present an analysis of the largest sample of Neandertal ossicles to date, including many previously unknown specimens, covering a wide geographic and temporal range. Microcomputed tomography scans and 3D geometric morphometrics were used to quantify shape and functional properties of the ossicles and the tympanic cavity and make comparisons with recent and extinct AMHs as well as African apes. We find striking morphological differences between ossicles of AMHs and Neandertals. Ossicles of both Neandertals and AMHs appear derived compared with the inferred ancestral morphology, albeit in different ways. Brain size increase evolved separately in AMHs and Neandertals, leading to differences in the tympanic cavity and, consequently, the shape and spatial configuration of the ossicles. Despite these different evolutionary trajectories, functional properties of the middle ear of AMHs and Neandertals are largely similar. The relevance of these functionally equivalent solutions is likely to conserve a similar auditory sensitivity level inherited from their last common ancestor

    Renormalization of Crumpled Manifolds

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    We consider a model of D-dimensional tethered manifold interacting by excluded volume in R^d with a single point. By use of intrinsic distance geometry, we first provide a rigorous definition of the analytic continuation of its perturbative expansion for arbitrary D, 0 < D < 2. We then construct explicitly a renormalization operation, ensuring renormalizability to all orders. This is the first example of mathematical construction and renormalization for an interacting extended object with continuous internal dimension, encompassing field theory.Comment: 10 pages (1 figure, included), harvmac, SPhT/92-15

    A New Technique for Detecting Supersymmetric Dark Matter

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    We estimate the event rate for excitation of atomic transition by photino-like dark matter. For excitations of several eV, this event rate can exceed naive cross-section by many orders of magnitude. Although the event rate for these atomic excitation is smaller than that of nuclear recoil off of non-zero spin nuclei, the photons emitted by the deexcitation are easier to detect than low-energy nuclear recoils. For many elements, there are several low-lying states with comparable excitation rates, thus, spectral ratios could be used to distinguish signal from background.Comment: 6 pages plain te
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