4,195 research outputs found

    Corruption in bank lending to firms : do competition and information sharing matter?

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    Building on the important study by Beck, Demirguc-Kunt and Levine (2006), we examine the effects of borrower and lender competition and information sharing νia credit registries/bureaus on corruption in bank lending. Using the unique World Bank dataset of the World Business Environment Survey (WBES) covering 58 countries and information on credit registries/bureaus and bank regulation assembled by other scholars, we find (1) strong evidence that banking competition reduces lending corruption and (2) the first and robust evidence that information sharing among banks (especially via private bureaus) contributes to reducing corruption in bank lending. We also find that government- and foreign-owned firms as well as exporting firms tend to be subject to less lending corruption, objective courts and better law enforcement tend to reduce lending corruption, and private and foreign ownership of the banking industry are associated with more integrity in lending. These findings pass a number of robustness tests and they are consistent with the predictions of a Nash bargaining model

    A new family-based association test via a least-squares method

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    To test the association between a dichotomous phenotype and genetic marker based on family data, we propose a least-squares method using the vector of phenotypes and their cross products within each family. This new approach allows covariate adjustment and is numerically much simpler to implement compared to likelihood- based methods. The new approach is asymptotically equivalent to the generalized estimating equation approach with a diagonal working covariance matrix, thus avoiding some difficulties with the working covariance matrix reported previously in the literature. When applied to the data from Collaborative Study on the Genetics of Alcoholism, this new method shows a significant association between the marker rs1037475 and alcoholism

    The influence of water immersion on the mechanical property of cement asphalt mortar and its implications on the slab track

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    Dynamic compression test of cement asphalt (CA) mortar specimens, due to water immersion history of 0d, 7d, 14d and 30d, are carried out using a universal electronic test machine, with the strain rates ranging from 1×10-5 s-1 to 1×10-2 s-1. The stress-strain full curves, the compressive strength and the elastic modulus of CA mortar at different strain rates and water immersion durations are analyzed and the effects of strain rates and water immersion duration on these behaviors are studied. Experimental results demonstrate that the compressive strength and elastic modulus increase with the strain rate. In the same strain rate, the compressive strength decreases with the increase of water immersion duration, but the elastic modulus decrease first and then increase with the increase of water immersion duration. The largest reduction of average compressive strength of CA mortar is 46.5 %, and the largest reduction in the average elastic modulus of CA mortar is 47.5 %. A vertical coupling vibration model for a vehicle-railway track-subgrade system was established on the base of wheel-rail coupling dynamics theory and experimental results. The effects of elastic modulus deterioration of CA mortar on the dynamic responses of the vehicle and railway track system were studied. The results show that the reduction of CA mortar has little influence on the dynamic properties of the track and the running stability

    An energy stable C<sup>0</sup> finite element scheme for a quasi-incompressible phase-field model of moving contact line with variable density

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    In this paper, we focus on modeling and simulation of two-phase flow with moving contact lines and variable density. A thermodynamically consistent phase-field model with General Navier Boundary Condition is developed based on the concept of quasi-incompressibility and the energy variational method. Then a mass conserving and energy stable C0 finite element scheme is developed to solve the PDE system. Various numerical simulation results show that the proposed schemes are mass conservative, energy stable and the 2nd order for P1 element and 3rd order for P2 element convergence rate in the sense of L2 norm

    Non-saturating large magnetoresistance in semimetals

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    The rapidly expanding class of quantum materials known as {\emph{topological semimetals}} (TSM) display unique transport properties, including a striking dependence of resistivity on applied magnetic field, that are of great interest for both scientific and technological reasons. However, experimental signatures that can identify or discern the dominant mechanism and connect to available theories are scarce. Here we present the magnetic susceptibility (χ\chi), the tangent of the Hall angle (tanθH\tan\theta_H) along with magnetoresistance in four different non-magnetic semimetals with high mobilities, NbP, TaP, NbSb2_2 and TaSb2_2, all of which exhibit non-saturating large MR. We find that the distinctly different temperature dependences, χ(T)\chi(T) and the values of tanθH\tan\theta_H in phosphides and antimonates serve as empirical criteria to sort the MR from different origins: NbP and TaP being uncompensated semimetals with linear dispersion, in which the non-saturating magnetoresistance arises due to guiding center motion, while NbSb2_2 and TaSb2_2 being {\it compensated} semimetals, with a magnetoresistance emerging from nearly perfect charge compensation of two quadratic bands. Our results illustrate how a combination of magnetotransport and susceptibility measurements may be used to categorize the increasingly ubiquitous non-saturating large magnetoresistance in TSMs.Comment: Accepted for publication at Proc. Natl. Acad. Sci., minor revisions, 6 figure

    Suppression of Superconductivity by Twin Boundaries in FeSe

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    Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate twin boundaries in stoichiometric FeSe films grown by molecular beam epitaxy. Twin boundaries can be unambiguously identified by imaging the 90{\deg} change in the orientation of local electronic dimers from Fe site impurities on either side. Twin boundaries run at approximately 45{\deg} to the Fe-Fe bond directions, and noticeably suppress the superconducting gap, in contrast with the recent experimental and theoretical findings in other iron pnictides. Furthermore, vortices appear to accumulate on twin boundaries, consistent with the degraded superconductivity there. The variation in superconductivity is likely caused by the increased Se height in the vicinity of twin boundaries, providing the first local evidence for the importance of this height to the mechanism of superconductivity.Comment: 6 pages, 7 figure
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