16,370 research outputs found

    Zeta-Regularization of the O(N) Non-Linear Sigma Model in D dimensions

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    The O(N) non-linear sigma model in a DD-dimensional space of the form RDM×TM{\bf R}^{D-M} \times {\bf T}^M, RDM×SM{\bf R}^{D-M} \times {\bf S}^M, or TM×SP{\bf T}^M \times {\bf S}^P is studied, where RM{\bf R}^M, TM{\bf T}^M and SM{\bf S}^M correspond to flat space, a torus and a sphere, respectively. Using zeta regularization and the 1/N1/N expansion, the corresponding partition functions and the gap equations are obtained. Numerical solutions of the gap equations at the critical coupling constants are given, for several values of DD. The properties of the partition function and its asymptotic behaviour for large DD are discussed. In a similar way, a higher-derivative non-linear sigma model is investigated too. The physical relevance of our results is discussed.Comment: 26 page

    Parasitic pumping currents in an interacting quantum dot

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    We analyze the charge and spin pumping in an interacting dot within the almost adiabatic limit. By using a non-equilibrium Green's function technique within the time-dependent slave boson approximation, we analyze the pumped current in terms of the dynamical constraints in the infinite-U regime. The results show the presence of parasitic pumping currents due to the additional phases of the constraints. The behavior of the pumped current through the quantum dot is illustrated in the spin-insensitive and in the spin-sensitive case relevant for spintronics applications

    Conformal Sector in D=6D=6 Quantum Gravity

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    We discuss the conformal factor dynamics in D=6D=6. Accepting the proposal that higher-derivative dimensionless terms in the anomaly-induced effective action may be dropped, we obtain a superrenormalizable (like in D=4D=4) effective theory for the conformal factor. The one-loop analysis of this theory gives the anomalous scaling dimension for the conformal factor and provides a natural mechanism to solve the cosmological constant problem.Comment: 9 pages, Oct 27 199

    Rancang Bangun Aplikasi Pelayanan dan Rekam Medis Calon Tenaga Kerja Indonesia pada AL-HUDA MEDICAL CENTER

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    Al-Huda Medical Center is special unit of Al-Huda hospital which manages check-up service for Prospective Indonesian Migrant Worker (CTKI). Al-Huda Medical Center wants to improve the service process and medical record of CTKI using computer system. There are five main problems found in the field regarding this matter, they include (1) all data reports consisting of registration to medical record database is still in paper-based documents, (2) the registration number is processed manually, (3) there is no barcode in health certificate, (4) specimen is labelled using handwriting (5) registration report, medical record, form, and film paper is done manually in terms of calculation and writing. The solution offered for the aforementioned problems is developing a web-based application which is able to manage service process, medical record, and report. Furthermore, this application provides health certificate which fulfills the standardization of the destination country of CTKI. This application also offers the more accurate reports compared to paper-based documentation

    Arthroscopic Anterior Shoulder Stabilization With Incorporation of a Comminuted Bony Bankart Lesion.

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    Bony Bankart lesions are a common finding in patients with anterior glenohumeral dislocation. Although there are no defined guidelines, small bony Bankart fractures are typically treated arthroscopically with suture anchors. The 2 main techniques used are double- and single-row suture anchor stabilization, with debate over superiority. Biomechanical studies have shown improved reduction and stabilization with the double-row over the single-row suture anchor technique; however, this has not been reported for small or comminuted bony fragments. Both techniques have shown promising preliminary clinical outcomes. In this Technical Note, we describe our preferred technique for arthroscopic instability repair using a single-row all-suture anchor method with the incorporation of a comminuted bony Bankart fragment in the lateral decubitus position

    Electrical switching and interferometry of massive Dirac particles in topological insulators constrictions

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    We investigate the electrical switching of charge and spin transport in a topological insulator nanoconstriction in a four terminal device. The switch of the edge channels is caused by the coupling between edge states which overlap in the constriction and by the tunneling effects at the contacts and therefore can be manipulated by tuning the applied voltages on the split-gate or by geometrical etching. The switching mechanism can be conveniently studied by electron interferometry involving the measurements of the current in different configurations of the side gates, while the applied bias from the external leads can be tuned to obtain pure charge or pure spin currents (charge- and spin- bias configurations). Relevant signatures of quantum confinement effects, quantum size effects and energy gap are evident in the Fabry-Perot physics of the device allowing for a full characterization of the charge and spin currents. The proposed electrical switching behavior offers an efficient tool to manipulate topological edge state transport in a controllable way.Comment: 10 pages; 14 figure

    Stellar population gradients from cosmological simulations: dependence on mass and environment in local galaxies

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    The age and metallicity gradients for a sample of group and cluster galaxies from N-body+hydrodynamical simulation are analyzed in terms of galaxy stellar mass. Dwarf galaxies show null age gradient with a tail of high and positive values for systems in groups and cluster outskirts. Massive systems have generally zero age gradients which turn to positive for the most massive ones. Metallicity gradients are distributed around zero in dwarf galaxies and become more negative with mass; massive galaxies have steeper negative metallicity gradients, but the trend flatten with mass. In particular, fossil groups are characterized by a tighter distribution of both age and metallicity gradients. We find a good agreement with both local observations and independent simulations. The results are also discussed in terms of the central age and metallicity, as well as the total colour, specific star formation and velocity dispersion.Comment: 9 pages, 5 figures, accepted for publication on MNRA
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