2,293 research outputs found

    Top-bottom mass hierarchy, s−μs-\mu puzzle and gauge coupling unification with split multiplets

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    A supersymmetric 5D SU(5) grand unification is considered. The SU(5) is broken down to GSM=SU(3)×SU(2)×U(1)G_{SM}=SU(3)\times SU(2)\times U(1) by the Z2×Z2′Z_2\times Z_2' assignment of the bulk field(s). The matter fields are located at the fixed point(s). In the bulk, a Higgs multiplet 5ˉH\bar 5_H(containing the bottom doublet H1H_1) and the SU(5) gauge multiplet are located. At one fixed point, H2H_2(the top doublet) and the standard model matter multiplets are presented. Because of the difference of the locations of H1H_1 and H2H_2, one can obtain a hierarchy between top and bottom Yukawa couplings. We also present a possibility to understand the s−μs-\mu mass puzzle in this framework of the split multiplet.Comment: LaTeX file of 17 pages including 3 eps figures. A note is added and typo errors corrected. To appear in Euro. Phys. J.

    Overlimiting Current and Shock Electrodialysis in Porous Media

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    Most electrochemical processes, such as electrodialysis, are limited by diffusion, but in porous media, surface conduction and electro-osmotic flow also contribute to ionic fluxes. In this paper, we report experimental evidence for surface-driven over-limiting current (faster than diffusion) and deionization shocks (propagating salt removal) in a porous medium. The apparatus consists of a silica glass frit (1 mm thick with 500 nm mean pore size) in an aqueous electrolyte (CuSO4_4 or AgNO3_3) passing ionic current from a reservoir to a cation-selective membrane (Nafion). The current-voltage relation of the whole system is consistent with a proposed theory based on the electro-osmotic flow mechanism over a broad range of reservoir salt concentrations (0.1 mM - 1.0 M), after accounting for (Cu) electrode polarization and pH-regulated silica charge. Above the limiting current, deionized water (≈10μ\approx 10 \mu MM) can be continuously extracted from the frit, which implies the existence of a stable shock propagating against the flow, bordering a depleted region that extends more than 0.5mm across the outlet. The results suggest the feasibility of "shock electrodialysis" as a new approach to water desalination and other electrochemical separations.Comment: 39 pages, 9 fig

    Density fluctuations in κ\kappa-deformed inflationary universe

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    We study the spectrum of metric fluctuation in κ\kappa-deformed inflationary universe. We write the theory of scalar metric fluctuations in the κ−\kappa-deformed Robertson-Walker space, which is represented as a non-local theory in the conventional Robertson-Walker space. One important consequence of the deformation is that the mode generation time is naturally determined by the structure of the κ−\kappa-deformation. We expand the non-local action in H2/κ2H^2/\kappa^2, with HH being the Hubble parameter and κ\kappa the deformation parameter, and then compute the power spectra of scalar metric fluctuations both for the cases of exponential and power law inflations up to the first order in H2/κ2H^2/\kappa^2. We show that the power spectra of the metric fluctuation have non-trivial corrections on the time dependence and on the momentum dependence compared to the commutative space results. Especially for the power law inflation case, the power spectrum for UV modes is weakly blue shifted early in the inflation and its strength decreases in time. The power spectrum of far-IR modes has cutoff proportional to k3k^3 which may explain the low CMB quadrupole moment.Comment: final revision; 19 pages, 3 figures; to appear in Phys. Rev.

    Holographic interacting dark energy in the braneworld cosmology

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    We investigate a model of brane cosmology to find a unified description of the radiation-matter-dark energy universe. It is of the interacting holographic dark energy with a bulk-holographic matter χ\chi. This is a five-dimensional cold dark matter, which plays a role of radiation on the brane. Using the effective equations of state ωΛeff\omega^{\rm eff}_{\rm \Lambda} instead of the native equations of state ωΛ\omega_{\rm \Lambda}, we show that this model cannot accommodate any transition from the dark energy with ωΛeff≥−1\omega^{\rm eff}_{\rm \Lambda}\ge-1 to the phantom regime ωΛeff<−1\omega^{\rm eff}_{\rm \Lambda}<-1. Furthermore, the case of interaction between cold dark matter and five dimensional cold dark matter is considered for completeness. Here we find that the redshift of matter-radiation equality zeqz_{\rm eq} is the same order as zeqob=2.4×104Ωmh2z^{\rm ob}_{\rm eq}=2.4\times10^{4} \Omega_{\rm m}h^2. Finally, we obtain a general decay rate Γ\Gamma which is suitable for describing all interactions including the interaction between holographic dark energy and cold dark matter.Comment: 17 pages, 4 figure

    What are They Saying About Your Head Coach? The Relationship Among Political Skill, Reputation, and Effectiveness

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    Influential leaders in competitive sport fields effectively use political skill to enhance their reputation, gain followers, and obtain support from organizations. In this study, a structural model was tested to determine the mediating role of leader reputation in the relationship between leader political skill and leader effectiveness. A total of 248 NCAA Division I assistant coaches were recruited for participation in a survey on their head coaches’ political skill, reputation, and perceived team-unit and leader-unit effectiveness. The results supported an indirect effect of head coaches’ reputation on their political skill and effectiveness, rather than a direct effect of political skill on leader effectiveness. On this basis, it was concluded that the strong and positive reputation that politically skilled head coaches build facilitates leader effectiveness in collegiate sports

    Noncommutative Field Theory from twisted Fock space

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    We construct a quantum field theory in noncommutative spacetime by twisting the algebra of quantum operators (especially, creation and annihilation operators) of the corresponding quantum field theory in commutative spacetime. The twisted Fock space and S-matrix consistent with this algebra have been constructed. The resultant S-matrix is consistent with that of Filk\cite{Filk}. We find from this formulation that the spin-statistics relation is not violated in the canonical noncommutative field theories.Comment: 13 pages, 1 figure, minor changes, add reference

    Gaugino mass in AdS space

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    We study supersymmetric QED in AdS4 with massless matter. At 1-loop the ultra-violet regulator of the theory generates a contribution to the gaugino mass that is naively inconsistent with unbroken supersymmetry. We show that this effect, known in flat space as anomaly mediated supersymmetry breaking, is required to cancel an infra-red contribution arising from the boundary conditions in AdS space, which necessarily break chiral symmetry. We also discuss an analogous UV/IR cancellation that is independent of supersymmetry.Comment: 20 pages, 1 figur

    Correction for Self-Heating When Using Thermometers as Heaters in Precision Control Applications

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    In precision control applications, thermometers have temperature-dependent electrical resistance with germanium or other semiconductor material thermistors, diodes, metal film and wire, or carbon film resistors. Because resistance readout requires excitation current flowing through the sensor, there is always ohmic heating that leads to a temperature difference between the sensing element and the monitored object. In this work, a thermistor can be operated as a thermometer and a heater, simultaneously, by continuously measuring the excitation current and the corresponding voltage. This work involves a method of temperature readout where the temperature offset due to self-heating is subtracted exactly

    The GLAS Algorithm Theoretical Basis Document for Precision Orbit Determination (POD)

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    The Geoscience Laser Altimeter System (GLAS) was the sole instrument for NASA's Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry mission. The primary purpose of the ICESat mission was to make ice sheet elevation measurements of the polar regions. Additional goals were to measure the global distribution of clouds and aerosols and to map sea ice, land topography and vegetation. ICESat was the benchmark Earth Observing System (EOS) mission to be used to determine the mass balance of the ice sheets, as well as for providing cloud property information, especially for stratospheric clouds common over polar areas. The GLAS instrument operated from 2003 to 2009 and provided multi-year elevation data needed to determine changes in sea ice freeboard, land topography and vegetation around the globe, in addition to elevation changes of the Greenland and Antarctic ice sheets. This document describes the Precision Orbit Determination (POD) algorithm for the ICESat mission. The problem of determining an accurate ephemeris for an orbiting satellite involves estimating the position and velocity of the satellite from a sequence of observations. The ICESatGLAS elevation measurements must be very accurately geolocated, combining precise orbit information with precision pointing information. The ICESat mission POD requirement states that the position of the instrument should be determined with an accuracy of 5 and 20 cm (1-s) in radial and horizontal components, respectively, to meet the science requirements for determining elevation change

    Poliovirus Infection Transiently Increases CopII Vesicle Budding

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    Poliovirus (PV) requires membranes of the host cell\u27s secretory pathway to generate replication complexes (RCs) for viral RNA synthesis. Recent work identified the intermediate compartment and the Golgi apparatus as the precursors of the replication organelles of PV (N. Y. Hsu et al., Cell 141:799-811, 2010). In this study, we examined the effect of PV on COPII vesicles, the secretory cargo carriers that bud from the endoplasmic reticulum and homotypically fuse to form the intermediate compartment that matures into the Golgi apparatus. We found that infection by PV results in a biphasic change in functional COPII vesicle biogenesis in cells, with an early enhancement and subsequent inhibition. Concomitant with the early increase in COPII vesicle formation, we found an increase in the membrane fraction of Sec16A, a key regulator of COPII vesicle formation. We suggest that the early burst in COPII vesicle formation detected benefits PV by increasing the precursor pool required for the formation of its RCs
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