2,724,214 research outputs found

    Kondo and anti-Kondo resonances in transport through nanoscale devices

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    We study the current through a quantum wire side coupled to a quantum dot, and compare it with the case of an embedded dot. The system is modeled by the Anderson Hamiltonian for a linear chain, with one atom either coupled to (side-dot) or substituted by (embedded dot) a magnetic impurity. For realistic (small) hopping of the dot to the rest of the system, an exact relationship between both conductivities holds. We calculate the temperature dependence for moderate values of the Coulomb repulsion U using an interpolative perturbative scheme. For sufficiently large U and temperature greater than the Kondo temperature, the conductance as a function of gate voltage displays two extrema.Comment: 6 pages, 6 figures, submitted to Phys. Rev.

    X-ray reflection in accreting stellar-mass black hole systems

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    The X-ray spectra of accreting stellar-mass black hole systems exhibit spectral features due to reflection, especially broad iron K alpha emission lines. We investigate the reflection by the accretion disc that can be expected in the high/soft state of such a system. First, we perform a self-consistent calculation of the reflection that results from illumination of a hot, inner portion of the disc with its atmosphere in hydrostatic equilibrium. Then we present reflection spectra for a range of illumination strengths and disc temperatures under the assumption of a constant-density atmosphere. Reflection by a hot accretion disc differs in important ways from that of a much cooler disc, such as that expected in an active galactic nucleus.Comment: 5 pages with 9 figures, accepted for publication in MNRA

    A note on R-currents and trace anomalies in the (2,0) tensor multiplet in d=6 and AdS/CFT correspondence

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    We discuss the two- and three-point functions of the SO(5) R-current of the (2,0) tensor multiplet in d=6, using AdS/CFT correspondence as well as a free field realization. The results obtained via AdS/CFT correspondence coincide with the ones from a free field calculation up to an overall 4N^3 factor. This is the same factor found recently in studies of the two- and three-point functions of the energy momentum tensor in the (2,0) theory. We also connect our results to the trace anomaly in d=6 in the presence of external vector fields and briefly discuss their implications.Comment: 11 pages, LaTeX; v4 derivation of sugra gauge coupling and references adde

    Design for waste-management system

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    Study was made and system defined for water-recovery and solid-waste processing for low-rise apartment complexes. System can be modified to conform with unique requirements of community, including hydrology, geology, and climate. Reclamation is accomplished by treatment process that features reverse-osmosis membranes

    Novel constraints on fermionic dark matter from galactic observables I: The Milky Way

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    We have recently introduced a new model for the distribution of dark matter (DM) in galaxies based on a self-gravitating system of massive fermions at finite temperatures, the Ruffini-Arg\"uelles-Rueda (RAR) model. We show that this model, for fermion masses in the keV range, explains the DM halo of the Galaxy and predicts the existence of a denser quantum core at the center. We demonstrate here that the introduction of a cutoff in the fermion phase-space distribution, necessary to account for the finite Galaxy size, defines a new solution with a central core which represents an alternative to the black hole (BH) scenario for SgrA*. For a fermion mass in the range mc2=48mc^2 = 48 -- 345345~keV, the DM halo distribution is in agreement with the Milky Way rotation curve data, while harbors a dense quantum core of about 4×106M4\times10^6 M_\odot within the S2-star pericenter.Comment: 11 pages, 5 figures. Published in Physics of the Dark Univers

    Physiological reactivity to spontaneously occurring seizure activity in dogs with epilepsy and their carers

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    There is a complex bidirectional relationship between stress and epilepsy. Stressful stimuli and subsequent cortisol release act as a trigger for seizure activity in some individuals with epilepsy, and seizure activity itself may act as a stressor to the affected individual. Epilepsy is the most common chronic neurological condition in domestic dogs and requires chronic management by their human carers, impacting upon the quality of life of both dog and carer. Seizures occur unpredictably and may be stressful for carers to witness and manage. In the present study we investigated the role of seizure activity as a stressor, measuring the effect of spontaneously occurring seizure activity in dogs with epilepsy upon their own cortisol levels and that of their carers. Furthermore, we tested whether individual differences in HPA reactivity were associated with owner personality characteristics and the quality of the dog carer relationship. Saliva samples were obtained from sixteen dog carer dyads in the home setting 20 and 40 minute post-seizure, and at time-matched points on the following (non-seizure) day. Significant differences in cortisol levels were found in dogs at 40 minute post-seizure (265.1% increase), and at 20 minute post-seizure in their carers (40.5% increase). No associations were found between cortisol reactivity and the strength of the dog-carer bond. Carers with higher neuroticism scores exhibited higher cortisol levels at both post-seizure sampling points. As there was a gender bias in the carer sample (15/16 were female), and there are known sex differences in cortisol reactivity in response to psychological stress, the conclusions of this study may be limited to female carers. These findings are the first to objectively demonstrate the acutely stressful effects of seizures in dogs with epilepsy and their carers

    Growth Hormone Gene Polymorphism and Its Association with Partial Cumulative Milk Yields of Holstein Friesian Dairy Cattle

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    Growth hormone gene (GH gene) plays an important role in regulating body growth and in developing mammary gland, similar with its interaction to specific receptors. The GH gene has been considered as one of candidate gene associated with selection on lactation trait and milk production. This study was aimed to determine genetic polymorphism of the GH-AluI gene and to associate its genotype variants on various 15-d partial cumulative milk yields in Holstein Friesian (HF) dairy cows. A number of 370 blood samples were collected from six HF populations, respectively from small dairy farmer under the supervision of the North Bandung Milk Cooperation (NBMC) in Cilumber (98) and Pasir Kemis village (96), Dairy Cattle Breeding and Improvement Station (Cikole DCBIS) Cikole (88), Lembang Artificial Insemination Center (Lembang AIC) (17), Singosari Artificial Insemination Center (Singosari AIC (32), and Cipelang Livestock Embryo Center (Cipelang LEC) (40). A polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) method was used to identify variant genotypes of the GH gene using AluI restriction enzyme. Genotyping results produced only two genotypes, i.e. LL and LV genotypes, without VV genotype. Frequency of the former was dominant, whilst that was low for the latter (89% vs. 11%); leading to the frequency of L allele was very high (94%) compared to that of V allele (6%). No significant association between variant genotypes (LL and LV) and various 15-d partial cumulative milk yields
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