2,995 research outputs found

    Parameter dependence of phase and log amplitude scintillation

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    Parameter dependence of phase and log amplitude scintillation - Signal statistics of spherical wave emitted by transmitter through intervening slab of irregularitie

    Monopoly power of the medical school market and high incomes of U.S. physicians

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    We expect the incomes of physicians to remain high in the next decades. Using the latest published physician income data (2015) we calculated the weighted median income of U.S. physicians and the net present value (NPV) of an investment in physician education. We estimated the NPV assuming that the physicians training began in 2007 and their practice would commence in 2015. We estimated the NPV of the lifetime earnings of a physician based on the median income of all physicians in the sample to be between 7.1and7.1 and 7.3 million. This finding of high NPV’s is consistent with almost all earlier studies of this kind. Physicians continue to experience relatively high incomes and very slow increases in the number of new graduates. We expect an excess demand for positions in medical colleges to continue. Our findings with respect to the incomes of non-primary physicians (surgeons, radiologist and cardiologists), indicate will continue to be much higher than those of primary physicians. There are strong evidence suggesting this is because of blockages in physician residency openings in these non-primary fields of medicine.peer-reviewe

    Characterization of the second- and third-order nonlinear optical susceptibilities of monolayer MoS2_2 using multiphoton microscopy

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    We report second- and third-harmonic generation in monolayer MoS2_\mathrm{2} as a tool for imaging and accurately characterizing the material's nonlinear optical properties under 1560 nm excitation. Using a surface nonlinear optics treatment, we derive expressions relating experimental measurements to second- and third-order nonlinear sheet susceptibility magnitudes, obtaining values of χs(2)=2.0×1020|\chi_s^{(2)}|=2.0\times10^{-20} m2^2 V1^{-1} and for the first time for monolayer MoS2_\mathrm{2}, χs(3)=1.7×1028|\chi_s^{(3)}|=1.7\times10^{-28} m3^3 V2^{-2}. These sheet susceptibilities correspond to effective bulk nonlinear susceptibility values of χb(2)=2.9×1011|\chi_{b}^{(2)}|=2.9\times10^{-11} m V1^{-1} and χb(3)=2.4×1019|\chi_{b}^{(3)}|=2.4\times10^{-19} m2^2 V2^{-2}, accounting for the sheet thickness. Experimental comparisons between MoS2_\mathrm{2} and graphene are also performed, demonstrating \sim3.4 times stronger third-order sheet nonlinearity in monolayer MoS2_\mathrm{2}, highlighting the material's potential for nonlinear photonics in the telecommunications C band.Comment: Accepted by 2D Materials, 28th Oct 201

    Self-Pulsating Semiconductor Lasers: Theory and Experiment

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    We report detailed measurements of the pump-current dependency of the self-pulsating frequency of semiconductor CD lasers. A distinct kink in this dependence is found and explained using rate-equation model. The kink denotes a transition between a region where the self-pulsations are weakly sustained relaxation oscillations and a region where Q-switching takes place. Simulations show that spontaneous emission noise plays a crucial role for the cross-over.Comment: Revtex, 16 pages, 7 figure

    Incommensurate magnetism near quantum criticality in CeNiAsO

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    Two phase transitions in the tetragonal strongly correlated electron system CeNiAsO were probed by neutron scattering and zero field muon spin rotation. For T<TN1T <T_{N1} = 8.7(3) K, a second order phase transition yields an incommensurate spin density wave with wave vector k=(0.44(4),0,0)\textbf{k} = (0.44(4), 0, 0). For T<TN2T < T_{N2} = 7.6(3) K, we find co-planar commensurate order with a moment of 0.37(5) μB0.37(5)~\mu_B, reduced to 30%30 \% of the saturation moment of the ±12|\pm\frac{1}{2}\rangle Kramers doublet ground state, which we establish by inelastic neutron scattering. Muon spin rotation in CeNiAs1xPxO\rm CeNiAs_{1-x}P_xO shows the commensurate order only exists for x \le 0.1 so the transition at xcx_c = 0.4(1) is from an incommensurate longitudinal spin density wave to a paramagnetic Fermi liquid
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