27,485 research outputs found

    Two monotonic functions involving gamma function and volume of unit ball

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    In present paper, we prove the monotonicity of two functions involving the gamma function Γ(x)\Gamma(x) and relating to the nn-dimensional volume of the unit ball Bn\mathbb{B}^n in Rn\mathbb{R}^n.Comment: 7 page

    Monotonicity results and bounds for the inverse hyperbolic sine

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    In this note, we present monotonicity results of a function involving to the inverse hyperbolic sine. From these, we derive some inequalities for bounding the inverse hyperbolic sine.Comment: 3 page

    A NEW GENERAL CONCEPTUAL APPROACH TO MODELING THE LIVESTOCK SECTOR: AN APPLICATION TO THE JAPANESE SWINE-PORK SECTOR

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    Many livestock sector models have limited coverage of relevant variables, and are somewhat ad hoc in their choice of what should be specified as behavioral equations. This study develops a generic conceptual approach to modeling the livestock sector that provides consistent rules of specification and better coverage of variables. This approach is then applied to the swine-pork sector of Japan. The new approach departs significantly from existing models. The structure clearly differentiates stock and flow variables; only flow variables have behavioral specifications and stock variables are accounting identities; flow variables are expressed in rates rather than levels; logistic functions are used in most flow variables to automatically impose biological-technological limits; and swine slaughter number and weight are disaggregated into sow and other swine (i.e., gilt-barrow). The estimated Japanese swine-pork model has good fit, no serial correlation, significant coefficients, correct signs, and is better able to capture both the mean and variability of all endogenous variables.Livestock Production/Industries, Research Methods/ Statistical Methods,

    Comparing Kalman Filters and Observers for Power System Dynamic State Estimation with Model Uncertainty and Malicious Cyber Attacks

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    Kalman filters and observers are two main classes of dynamic state estimation (DSE) routines. Power system DSE has been implemented by various Kalman filters, such as the extended Kalman filter (EKF) and the unscented Kalman filter (UKF). In this paper, we discuss two challenges for an effective power system DSE: (a) model uncertainty and (b) potential cyber attacks. To address this, the cubature Kalman filter (CKF) and a nonlinear observer are introduced and implemented. Various Kalman filters and the observer are then tested on the 16-machine, 68-bus system given realistic scenarios under model uncertainty and different types of cyber attacks against synchrophasor measurements. It is shown that CKF and the observer are more robust to model uncertainty and cyber attacks than their counterparts. Based on the tests, a thorough qualitative comparison is also performed for Kalman filter routines and observers.Comment: arXiv admin note: text overlap with arXiv:1508.0725

    Fluctuations in Number of Cercospora beticola Conidia in Relationship to Environment and Disease Severity in Sugar Beet

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    All content of Phytopathology is open access without restriction 12 months after publicationCercospora leaf spot, caused by Cercospora beticola, is the most damaging foliar disease of sugar beet in Minnesota (MN) and North Dakota (ND). Research was conducted to characterize the temporal progression of aerial concentration of C. beticola conidia in association with the environment and disease severity in sugar beet. In 2003 and 2004, volumetric spore traps were placed within inoculated sugar beet plots to determine daily dispersal of conidia at Breckenridge, MN, and St. Thomas, ND. Plots were rated weekly for disease severity. At both locations, conidia were first collected in early July 2003 and late June in 2004. Peaks of conidia per cubic meter of air were observed with maxima in late August 2003 and in early September 2004 at both locations. Peaks of airborne conidium concentration were significantly correlated with the average temperature of daily hours when relative humidity was greater than 87%. Weekly mean hourly conidia per cubic meter of air was significantly (P <0.01) associated with disease severity during both years and across locations. This study showed that C. beticola conidial numbers may be used to estimate potential disease severity that, with further research, could be incorporated in a disease forecasting model to rationalize Cercospora leaf spot management.Peer reviewe

    Isovector channel of quark-meson-coupling model and its effect on symmetry energy

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    The non-relativistic approximation of the quark-meson-coupling model has been discussed and compared with the Skyrme-Hartree-Fock model which includes spin exchanges. Calculations show that the spin-exchange interaction has important effect on the descriptions of finite nuclei and nuclear matter through the Fock exchange. Also in the quark-meson-coupling model, it is the Fock exchange that leads to a nonlinear density-dependent isovector channel and changes the density-dependent behavior of the symmetry energy.Comment: 20 pages, 9 figures and 1 table, accepted for publication in Nuclear Physics

    On the Application of Gluon to Heavy Quarkonium Fragmentation Functions

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    We analyze the uncertainties induced by different definitions of the momentum fraction zz in the application of gluon to heavy quarkonium fragmentation function. We numerically calculate the initial gJ/ψg \to J / \psi fragmentation functions by using the non-covariant definitions of zz with finite gluon momentum and find that these fragmentation functions have strong dependence on the gluon momentum k\vec{k}. As k| \vec{k} | \to \infty, these fragmentation functions approach to the fragmentation function in the light-cone definition. Our numerical results show that large uncertainties remains while the non-covariant definitions of zz are employed in the application of the fragmentation functions. We present for the first time the polarized gluon to J/ψJ/\psi fragmentation functions, which are fitted by the scheme exploited in this work.Comment: 11 pages, 7 figures;added reference for sec.

    Monotonicity and logarithmic convexity relating to the volume of the unit ball

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    Let Ωn\Omega_n stand for the volume of the unit ball in Rn\mathbb{R}^n for nNn\in\mathbb{N}. In the present paper, we prove that the sequence Ωn1/(nlnn)\Omega_{n}^{1/(n\ln n)} is logarithmically convex and that the sequence Ωn1/(nlnn)Ωn+11/[(n+1)ln(n+1)]\frac{\Omega_{n}^{1/(n\ln n)}}{\Omega_{n+1}^{1/[(n+1)\ln(n+1)]}} is strictly decreasing for n2n\ge2. In addition, some monotonic and concave properties of several functions relating to Ωn\Omega_{n} are extended and generalized.Comment: 12 page

    Generating EPR beams in a cavity optomechanical system

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    We propose a scheme to produce continuous variable entanglement between phase-quadrature amplitudes of two light modes in an optomechanical system. For proper driving power and detuning, the entanglement is insensitive with bath temperature and QQ of mechanical oscillator. Under realistic experimental conditions, we find that the entanglement could be very large even at room temperature.Comment: 4.1 pages, 4 figures, comments are welcome; to appear in PRA, published version with corrections of typo
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