1,073 research outputs found

    Lorentz invariance of entanglement classes in multipartite systems

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    We analyze multipartite entanglement in systems of spin-1/2 particles from a relativistic perspective. General conditions which have to be met for any classification of multipartite entanglement to be Lorentz invariant are derived, which contributes to a physical understanding of entanglement classification. We show that quantum information in a relativistic setting requires the partition of the Hilbert space into particles to be taken seriously. Furthermore, we study exemplary cases and show how the spin and momentum entanglement transforms relativistically in a multipartite setting.Comment: v2: 5 pages, 4 figures, minor changes to main body, journal references update

    Search for the Galactic accelerators of Cosmic-Rays up to the Knee with the Pevatron Test Statistic

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    The Pevatron Test Statistic (PTS) is applied to data from γ\gamma-ray observatories to test for the origin of Cosmic Rays (CRs) at energies around the knee of the CR spectrum. Several sources are analyzed within hadronic emission models. Previously derived results for RX J1713.7-3946, Vela Jr., and HESS J1745-290 are confirmed to demonstrate the concept, reliability, and advantages of the PTS. It is excluded with a significance more than 5σ5\sigma that the sources RX J1713.7-3946 and Vela Jr. are Pevatrons, while strong indications exceeding 4σ4\sigma are found for excluding HESS J1745-290 as a Pevatron. The importance to resolve source confusion with high angular resolution observations for Pevatrons searches is demonstrated using PTS for the region containing the SNR G106.3+2.7 and the Boomerang nebula. No statistically significant conclusion with respect to Pevatron associations could be drawn from this region, for the diffuse γ\gamma-ray emission around the Galactic Center, and the unidentified γ\gamma-ray sources LHAASO J2108++5157, HESS J1702-420A and MGRO J1908++06. Assuming the entire γ\gamma-ray emission from MGRO J1908+06 and the tail region of SNR G106.3+2.7 is hadronic, a statistical indication exceeding 3σ3\sigma is found for the underlying proton spectrum to extend beyond 350-400 TeV as a power-law. This result can indicate that these sources are proton and helium Pevatrons, in which the accelerated particles contribute to the knee of proton and helium spectra observed at Earth.Comment: Accepted for publication in MNRAS. 16 pages, 9 figure

    NUMERICAL STUDY OF THE GEOMETRIC INFLUENCE OF A FIN IN A CYLINDRICAL HEAT EXCHANGER FOR MELTING OF PCM

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    The thermal heat storage it’s an effective way to suit the energy availability with the demand schedule. It can be stored in the means of sensible or latent heat, the latter applying a material denominated Phase Change Material (PCM), which is provided as organic compounds, hydrated salts, paraffins, among others. The latent heat storage systems offer several advantages, like the practically isothermal process of loading and unloading and the high energy density. However, the low thermal conductivity makes the cycle prolonged on these systems, restricting its applicability. Applying computational fluid dynamics, the behavior of the PCM melting process was studied in cylindrical cavities with horizontal and vertical fins, aiming the optimization of the fin geometry. In this way the fin area was kept constant, varying its aspect ratio. The numerical model was validated with results from the literature and it’s composed of the continuity, momentum and energy equations increased by the phase change model. Qualitative and quantitative results are presented, referring to mesh independence, contours of velocity, net fraction and temperature at different moments of the process. The results of the study indicate that the position of the fin in the heat exchanger influences the melting process, although the vertical fins have a faster total melting process, horizontal fins can reach larger partial liquid fractions in less time in the heat exchanger. Such as the position of the fin, the increase of its length propitiates the reduction of the melting time, evidencing the optimal aspect ratio

    Effect of extended surfaces on lauric acid melting process in annular cavities

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    The objective of the present work is to parametrically analyze the effect of extended surfaces’ proportion and positioning on the lauric acid melting process, in an annular cavity. In total 46 geometric configurations were studied, varying between 5 area ratios, 5 proportions, and 2 positions of the extended surface. Numerical simulations performed with the finite volume method were used to conduct the study. The numerical model, composed of the continuity, momentum conservation, and energy conservation equations, plus the enthalpy-porosity phase change model, was validated with experimental data from the literature. The Grid Convergence Index (GCI) was used to evaluate the computational mesh, resulting in an average index of 0.0026%. The results are presented in terms of liquid fraction vs Fourier, and Nusselt number vs. Fourier. Besides, velocity vectors, and streamlines, liquid fraction, and temperature fields, were presented, comparing different instants and geometric arrangements. For the analysis of the results, the melting time was considered as a performance indicator. The results revealed that: while there is solid PCM in the cavity's upper section, the melting rate in systems with horizontal extensions is 15% higher than systems with vertical extensions; when the extended surface thinness is increased, the overall melting time is reduced by more than 10% in vertical arrangements and less than 1.5% in horizontal arrangements; the total melting time is nearly 45% faster in systems with vertical extensions than in systems with horizontal extensions

    Inspiratory muscle training reduces blood lactate concentration during volitional hyperpnoea

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    Although reduced blood lactate concentrations ([lac−]B) have been observed during whole-body exercise following inspiratory muscle training (IMT), it remains unknown whether the inspiratory muscles are the source of at least part of this reduction. To investigate this, we tested the hypothesis that IMT would attenuate the increase in [lac−]B caused by mimicking, at rest, the breathing pattern observed during high-intensity exercise. Twenty-two physically active males were matched for 85% maximal exercise minute ventilation (V˙Emax) and divided equally into an IMT or a control group. Prior to and following a 6 week intervention, participants performed 10 min of volitional hyperpnoea at the breathing pattern commensurate with 85% V˙Emax

    Cancer risk in HIV-infected individuals on HAART is largely attributed to oncogenic infections and state of immunocompetence

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    <p>Abstract</p> <p>Objectives</p> <p>To estimate the cancer risk of HIV-infected patients in the HAART era with respect to a general reference population and to determine risk factors for malignancy.</p> <p>Methods</p> <p>Long term (1996-2009) cancer incidence of the Bonn single centre HIV cohort was compared to the incidence of the reference population of Saarland using standardized incidence ratios (SIR). Poisson regression analysis was used to identify predictors of cancer risk.</p> <p>Results</p> <p>1,476 patients entered the cohort, enabling 8,772 person years of observation. 121 tumours in 114 patients, 7 in-situ and 114 invasive cancers, were identified. Malignancies associated with infectious agents such as Kaposi sarcoma (SIRs: male: 5,683; female: 277), non-Hodgkin lymphoma (SIRs male: 35; female: 18), anal cancer (SIRs male: 88; female: 115) as well a cervical carcinoma (SIR female: 4) and Hodgkin's disease (SIR male: 39) and liver cancer (SIR male: 18) were substantially more frequent in HIV-infected patients than in the general population (p < 0.001, each), whereas all other types of cancer were not increased. Poisson regression identified HAART (incidence rate ratio IRR (95% CI): 0.28 (0.19-0.41), p < 0.001), CD4 count (IRR per 100 cells/μl increase: 0.66 (0.57-0.76), p < 0.001), hepatitis B (IRR: 2.15 (1.10-4.20), p = 0.046) and age (IRR per 10 year increase: 1.23 (1.03 - 1.46), p = 0.023) as independent predictors for the occurrence of any type of cancer.</p> <p>Conclusions</p> <p>HAART and preserved CD4 cells preferentially reduce the risk of malignancies associated with oncogenic infections.</p

    Molecular Characterization of the Gastrula in the Turtle Emys orbicularis: An Evolutionary Perspective on Gastrulation

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    Due to the presence of a blastopore as in amphibians, the turtle has been suggested to exemplify a transition form from an amphibian- to an avian-type gastrulation pattern. In order to test this hypothesis and gain insight into the emergence of the unique characteristics of amniotes during gastrulation, we have performed the first molecular characterization of the gastrula in a reptile, the turtle Emys orbicularis. The study of Brachyury, Lim1, Otx2 and Otx5 expression patterns points to a highly conserved dynamic of expression with amniote model organisms and makes it possible to identify the site of mesoderm internalization, which is a long-standing issue in reptiles. Analysis of Brachyury expression also highlights the presence of two distinct phases, less easily recognizable in model organisms and respectively characterized by an early ring-shaped and a later bilateral symmetrical territory. Systematic comparisons with tetrapod model organisms lead to new insights into the relationships of the blastopore/blastoporal plate system shared by all reptiles, with the blastopore of amphibians and the primitive streak of birds and mammals. The biphasic Brachyury expression pattern is also consistent with recent models of emergence of bilateral symmetry, which raises the question of its evolutionary significance

    Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags

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    Using the ARGUS detector at the e+ee^+ e^- storage ring DORIS II, we have measured the Michel parameters ρ\rho, ξ\xi, and ξδ\xi\delta for τ±l±ννˉ\tau^{\pm}\to l^{\pm} \nu\bar\nu decays in τ\tau-pair events produced at center of mass energies in the region of the Υ\Upsilon resonances. Using τρν\tau^\mp \to \rho^\mp \nu as spin analyzing tags, we find ρe=0.68±0.04±0.08\rho_{e}=0.68\pm 0.04 \pm 0.08, ξe=1.12±0.20±0.09\xi_{e}= 1.12 \pm 0.20 \pm 0.09, ξδe=0.57±0.14±0.07\xi\delta_{e}= 0.57 \pm 0.14 \pm 0.07, ρμ=0.69±0.06±0.08\rho_{\mu}= 0.69 \pm 0.06 \pm 0.08, ξμ=1.25±0.27±0.14\xi_{\mu}= 1.25 \pm 0.27 \pm 0.14 and ξδμ=0.72±0.18±0.10\xi\delta_{\mu}= 0.72 \pm 0.18 \pm 0.10. In addition, we report the combined ARGUS results on ρ\rho, ξ\xi, and ξδ\xi\delta using this work und previous measurements.Comment: 10 pages, well formatted postscript can be found at http://pktw06.phy.tu-dresden.de/iktp/pub/desy97-194.p

    Residential exposure to plasticizers and its possible role in the pathogenesis of asthma.

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    The plasticizer di(2-ethylhexyl) phthalate (DEHP) is widely used in building materials. DEHP is identified as the major plasticizer exposure in dwellings. We provide evidence that inhalation exposure to DEHP as aerosols adsorbed to particulate matter is as important, or more important, than vapor phase exposure. The particulate inhalation exposure to DEHP is considered to be significant due to its low clearance and extensive penetration into the pulmonary region. DEHP is capable of creating high local concentrations in the airways at the deposition site with subsequent local effects. The proposed mechanism of effect states that mono(2-ethylhexyl) phthalate (MEHP), the primary hydrolysis product of DEHP, mimics the inducing prostaglandins (PG) PGD(2), 9alpha,11betaPGF2, and PGF2alpha, and thromboxanes in the lungs, thereby increasing the risk of inducing inflammation in the airways, which is a characteristic of asthma
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