51,071 research outputs found

    Self-generated Self-similar Traffic

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    Self-similarity in the network traffic has been studied from several aspects: both at the user side and at the network side there are many sources of the long range dependence. Recently some dynamical origins are also identified: the TCP adaptive congestion avoidance algorithm itself can produce chaotic and long range dependent throughput behavior, if the loss rate is very high. In this paper we show that there is a close connection between the static and dynamic origins of self-similarity: parallel TCPs can generate the self-similarity themselves, they can introduce heavily fluctuations into the background traffic and produce high effective loss rate causing a long range dependent TCP flow, however, the dropped packet ratio is low.Comment: 8 pages, 12 Postscript figures, accepted in Nonlinear Phenomena in Complex System

    Coagulation and anticoagulation in idiopathic pulmonary fibrosis

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    Idiopathic pulmonary fibrosis (IPF) is an incurable, progressive interstitial lung disease with a prognosis that is worse than that of many cancers. Epidemiological studies have demonstrated a link between IPF and thrombotic vascular events. Coagulation and fibrinolytic systems play central roles in wound healing and repair, processes hypothesised to be abnormal within the IPF lung. Animal models of pulmonary fibrosis have demonstrated an imbalance between thrombosis and fibrinolysis within the alveolar compartment, a finding that is also observed in IPF patients. A systemic prothrombotic state also occurs in IPF and is associated with increased mortality, but trials of anticoagulation in IPF have provided conflicting results. Differences in methodology, intervention and study populations may contribute to the inconsistent trial outcomes. The new oral anticoagulants have properties that may prove advantageous in targeting both thrombotic risk and progression of lung fibrosis

    Universal Amplitude Ratios of The Renormalization Group: Two-Dimensional Tricritical Ising Model

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    The scaling form of the free-energy near a critical point allows for the definition of various thermodynamical amplitudes and the determination of their dependence on the microscopic non-universal scales. Universal quantities can be obtained by considering special combinations of the amplitudes. Together with the critical exponents they characterize the universality classes and may be useful quantities for their experimental identification. We compute the universal amplitude ratios for the Tricritical Ising Model in two dimensions by using several theoretical methods from Perturbed Conformal Field Theory and Scattering Integrable Quantum Field Theory. The theoretical approaches are further supported and integrated by results coming from a numerical determination of the energy eigenvalues and eigenvectors of the off-critical systems in an infinite cylinder.Comment: 61 pages, Latex file, figures in a separate fil

    Solar Spectrum (SOLSPEC) measurement from 180 to 3000 nanometers

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    The SOLSPEC experiment, planned for the Atmospheric Laboratory for Applications and Science (ATLAS 1) NASA mission, is described. The purpose of this experiment is the measurement of the absolute solar irradiances in the wavelength range from 180 to 3000 nm and the variabilities of the solar irradiances in this wavelength range. Measurements of the irradiances and variabilities are used in: (1) solar-terrestrial/planetary relationships, in particular aeronomy of the stratosphere and mesosphere; (2) climatoglogy; and (3) solar physics

    Paired composite fermion wavefunctions

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    We construct a family of BCS paired composite fermion wavefunctions that generalize, but remain in the same topological phase as, the Moore-Read Pfaffian state for the half-filled Landau level. It is shown that for a wide range of experimentally relevant inter-electron interactions the groundstate can be very accurately represented in this form.Comment: 4 pages, 2 figure

    Charge storage mechanism in nanoporous carbons and its consequence for electrical double layer capacitors

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    Electrochemical capacitors, also known as supercapacitors, are energy storage devices that fill the gap between batteries and dielectric capacitors. Thanks to their unique features, they have a key role to play in energy storage and harvesting, acting as a complement to or even a replacement of batteries which has already been achieved in various applications. One of the challenges in the supercapacitor area is to increase their energy density. Some recent discoveries regarding ion adsorption in microporous carbon exhibiting pores in the nanometre range can help in designing the next generation of high-energy-density supercapacitors

    Use of an audio-paced incremental swimming test in young national-level swimmers

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    Purpose:To evaluate the reliability and sensitivity to training of an audio-paced incremental swimming test.Methods:Eight young national-level male swimmers (age 15 ± 1 year) performed a 7 × 200-m incremental swimming test (velocities 1.19, 1.24, 1.28, 1.33, 1.39, and 1.45 m/s and maximal sprint pace) using an audio-pacing device. The same test was performed 4 times by each participant, 1 wk apart to assess reliability (WK1, WK2) and after 9 and 20 wk of training (WK9, WK20). Blood lactate concentration ([La−]) and heart rate (HR) were recorded after each stage. Outcome measures were the velocity (v) and HR at lactate markers of 2 mM, 4 mM, and Δ1 mM.Results:Velocities at the lactate markers proved to be more reliable than HR, with typical errors ranging from 0.66% to 2.30% and 1.28% to 4.50%, respectively (shifts in mean ranged –0.91% to 0.73% and –0.84% to 1.79%, respectively). Across WK1, WK9, and WK20 there were significant improvements in peak velocity (P &lt; .001) and each of the velocities associated with the lactate markers (P &lt; .05), whereas only HR at Δ1 mM improved (P &lt; .05).Conclusions:This article demonstrates that an audio-paced incremental swimming test is reliable for use with junior swimmers and is sensitive to changes observed after training. The postswimming measurement of HR in the pool was comparatively less reliable.</jats:sec
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