9,978 research outputs found

    How Elastic is The Demand for Labor?

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    This paper investigates the magnitude of the elasticity of demand for labor in time series data using more general and complete models of demand than have been previously employed. It argues that previous analyses have imposed two invalid constraints in calculations, which bias downward estimated elasticities. The first invalid constraint is the assumption that real capital prices have an equal opposite effect to real wages in the demand equation. We show on measurement error grounds that this constraint should not be imposed in econometric work even when long run homogeneity of prices correctly characterizes the market. The constraint is rejected in the data. The second invalid constraint is that all explanatory variables have the same lag distribution. We argue that this constraint is invalid when decisions are made under uncertainty and find that it is also rejected by the data. The principal positive empirical finding is that with the constraints relaxed, the elasticity, of demand with respect to real wages is much larger than the estimates in the literature, indicating much greater price responsiveness on the demand side of the labor market than has previously been thought.

    An extension of SaalschĂŒtz's summation theorem for the series <sub><i>r</i>+3</sub>F<sub><i>r</i>+2</sub>

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    The aim in this research note is to provide an extension of SaalschĂŒtz's summation theorem for the series r+3Fr+2(1) when r pairs of numeratorial and denominatorial parameters differ by positive integers. The result is obtained by exploiting a generalization of an Euler-type transformation recently derived by Miller and Paris [Transformation formulas for the generalized hypergeometric function with integral parameter differences. Rocky Mountain J Math. 2013;43, to appear]

    On a new class of summation formulae involving the Laguerre polynomial

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    By elementary manipulation of series, a general transformation involving the generalized hypergeometric function is established. Kummer’s first theorem, the classical Gauss summation theorem and the generalized Kummer summation theorem due to Lavoie et al. [Generalizations of Whipple’s theorem on the sum of a 3 F 2, J. Comput. Appl. Math. 72 (1996), pp. 293–300] are then applied to obtain a new class of summation formulae involving the Laguerre polynomial, which have not previously appeared in the literature. Several related results due to Exton have also been given in a corrected form

    On two Thomae-type transformations for hypergeometric series with integral parameter differences

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    We obtain two new Thomae-type transformations for hypergeometric series with r pairs of numeratorial and denominatorial parameters differing by positive integers. This is achieved by application of the so-called Beta integral method developed by Krattenthaler and Rao [Symposium on Symmetries in Science (ed. B. Gruber), Kluwer (2004)] to two recently obtained Euler-type transformations. Some special cases are given

    Quartz-based flat-crystal resonant inelastic x-ray scattering spectrometer with sub-10 meV energy resolution

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    Continued improvement of the energy resolution of resonant inelastic x-ray scattering (RIXS) spectrometers is crucial for fulfilling the potential of this technique in the study of electron dynamics in materials of fundamental and technological importance. In particular, RIXS is the only alternative tool to inelastic neutron scattering capable of providing fully momentum resolved information on dynamic spin structures of magnetic materials, but is limited to systems whose magnetic excitation energy scales are comparable to the energy resolution. The state-of-the-art spherical diced crystal analyzer optics provides energy resolution as good as 25 meV but has already reached its theoretical limit. Here, we demonstrate a novel sub-10meV RIXS spectrometer based on flat-crystal optics at the Ir-L3_3 absorption edge (11.215∌\sim keV) that achieves an analyzer energy resolution of 3.9∌\simmeV, very close to the theoretical value of 3.7∌\simmeV. In addition, the new spectrometer allows efficient polarization analysis without loss of energy resolution. The performance of the instrument is demonstrated using longitudinal acoustical and optical phonons in diamond, and magnon in Sr3_3Ir2_2O7_7. The novel sub-10∌\simmeV RIXS spectrometer thus provides a window into magnetic materials with small energy scales

    Hydrodynamic propulsion of human sperm

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    The detailed fluid mechanics of sperm propulsion are fundamental to our understanding of reproduction. In this paper, we aim to model a human sperm swimming in a microscope slide chamber. We model the sperm itself by a distribution of regularized stokeslets over an ellipsoidal sperm head and along an infinitesimally thin flagellum. The slide chamber walls are modelled as parallel plates, also discretized by a distribution of regularized stokeslets. The sperm flagellar motion, used in our model, is obtained by digital microscopy of human sperm swimming in slide chambers. We compare the results of our simulation with previous numerical studies of flagellar propulsion, and compare our computations of sperm kinematics with those of the actual sperm measured by digital microscopy. We find that there is an excellent quantitative match of transverse and angular velocities between our simulations and experimental measurements of sperm. We also find a good qualitative match of longitudinal velocities and computed tracks with those measured in our experiment. Our computations of average sperm power consumption fall within the range obtained by other authors. We use the hydrodynamic model, and a prototype flagellar motion derived from experiment, as a predictive tool, and investigate how sperm kinematics are affected by changes to head morphology, as human sperm have large variability in head size and shape. Results are shown which indicate the increase in predicted straight-line velocity of the sperm as the head width is reduced and the increase in lateral movement as the head length is reduced. Predicted power consumption, however, shows a minimum close to the normal head aspect ratio

    Impact of Transporter Polymorphisms on Drug Development: Is It Clinically Significant?

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    Drug transporters are becoming increasingly recognized as relevant to the drug development process. This may be a reflection of increasing target complexity and the need for high-affinity interaction with drug targets that minimize off-target side effects. Moreover, as new molecular entities (NMEs) become larger in size and amphipathic in nature, interaction with drug transporters, both uptake as well as efflux, becomes increasingly likely. In some cases transporters may limit the absorption or organ-specific entry of NMEs, whereas in other cases transporters may enhance their absorption or tissue accumulation. Indeed, in some cases, transporters may prove to be a therapeutic target. Accordingly, a better understanding of potentially clinically relevant drug transporter polymorphisms earlier in the drug development process is highly desirable. In this review we examine key transporters that are important to the absorption, distribution, and excretion of a large number of drugs in clinical use. Importantly, we provide our assessment of the potential impact of known polymorphisms in such transporters and discuss whether there is sufficient evidence to incorporate these polymorphisms in the drug development process

    Solid-state metathesis reactions under pressure: A rapid route to crystalline gallium nitride

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    High pressure chemistry has traditionally involved applying pressure and increasing temperature until conditions become thermodynamically favorable for phase transitions or reactions to occur. Here, high pressure alone is used as a starting point for carrying out rapid, self-propagating metathesis reactions. By initiating chemical reactions under pressure, crystalline phases, such as gallium nitride, can be synthesized which are inaccessible when initiated from ambient conditions. The single-phase gallium nitride made by metathesis reactions under pressure displays significant photoluminescence intensity in the blue/ultraviolet region. The absence of size or surface-state effects in the photoluminescence spectra show that the crystallites are of micron dimensions. The narrow lines of the x-ray diffraction patterns and scanning electron microscopy confirm this conclusion. Brightly luminescent thin films can be readily grown using pulsed laser deposition

    Some new results for the Kampé de Fériet function with an application

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    The generalized hypergeometric functions in one and several variables and their natural generalizations appear in many mathematical problems and their applications. The theory of generalized hypergeometric functions in several variables comes from the fact that the solutions of the partial differential equations appearing in a large number of applied problems of mathematical physics have been expressed in terms of such generalized hypergeometric functions. In particular, the Kampé de Fériet function (in two variables) has proved its practical utility in representing solutions to a wide range of problems in pure and applied mathematics, statistics, and mathematical physics. In this context, in a very recent paper, Progri successfully calculated the 2F2 generalized hypergeometric function for a particular set of parameters and expressed the result in terms of the difference between two Kampé de Fériet functions. Inspired by his work, in the present paper, we obtain three results for a terminating 3F2 series of arguments 1 and 2, together with a transformation formula of a 3F2(z) generalized hypergeometric function in terms of the difference between two Kampé de Fériet functions. One application of this result is also provided. The paper concludes with six reduction formulas for the Kampé de Fériet function. Of note, symmetry occurs naturally in the generalized hypergeometric functions pFq and the Kampé de Fériet function involving two variables, which are the two most important functions discussed in this paper

    Critical Exponents of the Four-State Potts Model

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    The critical exponents of the four-state Potts model are directly derived from the exact expressions for the latent heat, the spontaneous magnetization, and the correlation length at the transition temperature of the model.Comment: LaTex, 7 page
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