3,388 research outputs found

    Land-use change simulation and assessment of driving factors in the loess hilly region - a case study as Pengyang County

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    The main objective of this study is to evaluate the land-use change and its relationship with its driving factors in the loess hilly region. In this study, a case study was carried out in Pengyang County. We set two land-use demand scenarios (a baseline scenario (scenario 1) and a real land-use requirement scenario (scenario 2)) during year 2001-2005 via assuming the effect of driving factors on land-use change keeps stable from 1993 to 2005. Two simulated land-use patterns of 2005 are therefore achieved accordingly by use of the conversion of land use and its effects model at small regional extent. Kappa analyses are conducted to compare each simulated land-use pattern with the reality. Results show that (1) the associated kappa values were decreased from 0.83 in 1993-2000 to 0.27 (in scenario 1) and 0.23 (in scenario 2) in 2001-2005 and (2) forest and grassland were the land-use types with highest commission errors, which implies that conversion of both the land-use types mentioned above is the main determinant of change of kappa values. Our study indicates the land-use change was driven by the synthetic multiply factors including natural and social-economic factors (e.g., slope, aspect, elevation, distance to road, soil types, and population dense) in 1993-2000 until "Grain for Green Project" was implemented and has become the dominant factor in 2001-2005

    Flavor Symmetry for Quarks and Leptons

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    Present data on neutrino masses and mixing favor the highly symmetric tribimaximal neutrino mixing matrix which suggests an underlying flavor symmetry. A systematic study of non-abelian finite groups of order g31g \leq 31 reveals that tribimaximal mixing can be derived not only from the well known tetrahedral flavor symmetry TA4T \equiv A_4, but also by using the binary tetrahedral symmetry TSL2(F3)T^{'} \equiv SL_2(F_3) which does not contain the tetrahedral group as a subgroup. TT^{'} has the further advantage that it can also neatly accommodate the quark masses including a heavy top quark.Comment: 12 pages latex. More typos correcte

    Non-vanishing boundary effects and quasi-first order phase transitions in high dimensional Ising models

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    In order to gain a better understanding of the Ising model in higher dimensions we have made a comparative study of how the boundary, open versus cyclic, of a d-dimensional simple lattice, for d=1,...,5, affects the behaviour of the specific heat C and its microcanonical relative, the entropy derivative -dS/dU. In dimensions 4 and 5 the boundary has a strong effect on the critical region of the model and for cyclic boundaries in dimension 5 we find that the model displays a quasi first order phase transition with a bimodal energy distribution. The latent heat decreases with increasing systems size but for all system sizes used in earlier papers the effect is clearly visible once a wide enough range of values for K is considered. Relations to recent rigorous results for high dimensional percolation and previous debates on simulation of Ising models and gauge fields are discussed.Comment: 12 pages, 27 figure

    Transonic Shocks In Multidimensional Divergent Nozzles

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    We establish existence, uniqueness and stability of transonic shocks for steady compressible non-isentropic potential flow system in a multidimensional divergent nozzle with an arbitrary smooth cross-section, for a prescribed exit pressure. The proof is based on solving a free boundary problem for a system of partial differential equations consisting of an elliptic equation and a transport equation. In the process, we obtain unique solvability for a class of transport equations with velocity fields of weak regularity(non-Lipschitz), an infinite dimensional weak implicit mapping theorem which does not require continuous Frechet differentiability, and regularity theory for a class of elliptic partial differential equations with discontinuous oblique boundary conditions.Comment: 54 page

    Electromagnetic proton form factors in large NcN_{c} QCD

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    The electromagnetic form factors of the proton are obtained using a particular realization of QCD in the large NcN_c limit (QCD{QCD}_{\infty}), which sums up the infinite number of zero-width resonances to yield an Euler's Beta function (Dual-QCD{QCD}_{\infty}). The form factors F1(q2)F_1(q^2) and F2(q2)F_2(q^2), as well as GM(q2)G_M(q^2) agree very well with reanalyzed space-like data in the whole range of momentum transfer. In addition, the predicted ratio μpGE/GM\mu_p G_E/G_M is in good agreement with recent polarization transfer measurements at Jefferson Lab.Comment: 10 page

    Factors Influencing Resection in Locoregional Pancreatic Cancer Patients

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    Objective: Identify factors associated with resection in a national sample of locoregional pancreatic cancer patients. Poster presented at ISPOR conference in Washington DC.https://jdc.jefferson.edu/jcphposters/1008/thumbnail.jp

    Fast Zonal Field Dynamo in Collisionless Kinetic Alfven Wave Turbulence

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    The possibility of fast dynamo action by collisionless kinetic Alfven Wave turbulence is demonstrated. The irreversibility necessary to lock in the generated field is provided by electron Landau damping, so the induced electric field does not vanish with resistivity. Mechanisms for self-regulation of the system and the relation of these results to the theory of alpha quenching are discussed. The dynamo-generated fields have symmetry like to that of zonal flows, and thus are termed zonal fields

    On the effects of (partial) quenching on penguin contributions to K-> pi pi

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    Recently, we pointed out that chiral transformation properties of strong penguin operators change in the transition from unquenched to (partially) quenched QCD. As a consequence, new penguin-like operators appear in the (partially) quenched theory, along with new low-energy constants, which should be interpreted as a quenching artifact. Here, we extend the analysis to the contribution of the new low-energy constants to the K^0 -> pi^+ pi^- amplitude, at leading order in chiral perturbation theory, and for arbitrary (momentum non-conserving) kinematics. Using these results, we provide a detailed discussion of the intrinsic systematic error due to this (partial) quenching artifact. We also give a simple recipe for the determination of the leading-order low-energy constant parameterizing the new operators in the case of strong LRLR penguins.Comment: 17 pages, 1 figure, minor correction

    Compactness and existence results in weighted Sobolev spaces of radial functions. Part II: Existence

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    We prove existence and multiplicity results for finite energy solutions to the nonlinear elliptic equation u+V(x)u=g(x,u)in ΩRN, N3, -\triangle u+V\left( \left| x\right| \right) u=g\left( \left| x\right| ,u\right) \quad \textrm{in }\Omega \subseteq \mathbb{R}^{N},\ N\geq 3, where Ω\Omega is a radial domain (bounded or unbounded) and uu satisfies u=0u=0 on Ω\partial \Omega if ΩRN\Omega \neq \mathbb{R}^{N} and u0u\rightarrow 0 as x\left| x\right| \rightarrow \infty if Ω\Omega is unbounded. The potential VV may be vanishing or unbounded at zero or at infinity and the nonlinearity gg may be superlinear or sublinear. If gg is sublinear, the case with g(,0)0g\left( \left| \cdot \right| ,0\right) \neq 0 is also considered.Comment: 29 pages, 8 figure

    Literature Review on Hospital Costs for Patients Undergoing Colectomy

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    Objective: This study aims to identify the range of direct hospital costs associated with a minimally invasive or open colectomy procedure across different countries. Poster presented at 2016 ISPOR conference in Washington DC.https://jdc.jefferson.edu/jcphposters/1009/thumbnail.jp
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