739 research outputs found

    Operationalizing Culture, Race and Ethnicity

    Get PDF

    Soybean Amino Acids in Health, Genetics, and Evaluation

    Get PDF
    Soybean is an important source of protein and amino acids for humans and livestock because of its well-balanced amino acid profile. This chapter outlines the strengths and weaknesses of soybean as a complete amino acid source as well as the relative importance of individual amino acids. Special attention is paid to the sulfur-containing amino acids, methionine and cysteine. Breeding and genetic engineering efforts are summarized to highlight previous accomplishments in amino acid improvement and potential avenues for future research. Agronomic properties and processing methods that affect amino acid levels in soybean food and feed are also explained. A brief introduction into current amino acid evaluation techniques is provided. By understanding the complexities of amino acids in soybean, protein quality for humans and livestock can be maximized

    A QCD Sum Rule Approach to the sdγs\to d\gamma Contribution to the ΩΞγ\Omega^-\to \Xi^-\gamma Radiative Decay

    Full text link
    QCD sum rules are used to calculate the contribution of short-distance single-quark transition sdγs\rightarrow d \gamma, to the amplitudes of the hyperon radiative decay, ΩΞγ\Omega^-\rightarrow \Xi^-\gamma. We re-evaluate the Wilson coefficient of the effective operator responsible for this transition. We obtain a branching ratio which is comparable to the unitarity limit.Comment: 15 pages, Revtex, 13 figures available as a uuencoded, gz-compressed ps fil

    Instanton vibrations of the 3-Skyrmion

    Get PDF
    The Atiyah-Drinfeld-Hitchin-Manin matrix corresponding to a tetrahedrally symmetric 3-instanton is calculated. Some small variations of the matrix correspond to vibrations of the instanton-generated 3-Skyrmion. These vibrations are decomposed under tetrahedral symmetry and this decomposition is compared to previous knowledge of the 3-Skyrmion vibration spectrum.Comment: 10 pages, LaTeX, no figures, PRD version with longer introduction and minor change

    Long Distance Contribution to sdγs \to d\gamma and Implications for ΩΞγ,BsBdγ\Omega^-\to \Xi ^-\gamma, B_s \to B_d^*\gamma and bsγb \to s\gamma

    Full text link
    We estimate the long distance (LD) contribution to the magnetic part of the sdγs \to d\gamma transition using the Vector Meson Dominance approximation (V=ρ,ω,ψi)(V=\rho,\omega,\psi_i). We find that this contribution may be significantly larger than the short distance (SD) contribution to sdγs \to d\gamma and could possibly saturate the present experimental upper bound on the ΩΞγ\Omega^-\to \Xi^-\gamma decay rate, ΓΩΞγMAX3.7×109\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} \simeq 3.7\times10^{-9}eV. For the decay BsBdγB_s \to B^*_d\gamma, which is driven by sdγs \to d\gamma as well, we obtain an upper bound on the branching ratio BR(BsBdγ)<3×108BR(B_s \to B_d^*\gamma)<3\times10^{-8} from ΓΩΞγMAX\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma}. Barring the possibility that the Quantum Chromodynamics coefficient a2(ms)a_2(m_s) be much smaller than 1, ΓΩΞγMAX\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} also implies the approximate relation 23igψi2(0)mψi212gρ2(0)mρ2+16gω2(0)mω2\frac{2}{3} \sum_i \frac{g^2_{\psi_i}(0)}{m^2_{\psi_i}} \simeq \frac{1}{2} \frac{g^2_\rho(0)}{m^2_\rho} + \frac{1}{6}\frac{g^2_\omega(0)}{m^2_\omega}. This relation agrees quantitatively with a recent independent estimate of the l.h.s. by Deshpande et al., confirming that the LD contributions to bsγb \to s\gamma are small. We find that these amount to an increase of (4±2)%(4\pm2)\% in the magnitude of the bsγb \to s \gamma transition amplitude, relative to the SD contribution alone.Comment: 16 pages, LaTeX fil

    Mean first-passage time of surface-mediated diffusion in spherical domains

    Full text link
    We present an exact calculation of the mean first-passage time to a target on the surface of a 2D or 3D spherical domain, for a molecule alternating phases of surface diffusion on the domain boundary and phases of bulk diffusion. The presented approach is based on an integral equation which can be solved analytically. Numerically validated approximation schemes, which provide more tractable expressions of the mean first-passage time are also proposed. In the framework of this minimal model of surface-mediated reactions, we show analytically that the mean reaction time can be minimized as a function of the desorption rate from the surface.Comment: to appear in J. Stat. Phy

    Influence of Carbon Concentration on the Superconductivity in MgCxNi3

    Full text link
    The influence of carbon concentration on the superconductivity (SC) in MgCx_{x}Ni3_3 has been investigated by measuring the low temperature specific heat combined with first principles electronic structure calculation. It is found that the specific heat coefficient γn=Cen/T\gamma_n=C_{en}/T of the superconducting sample (x1x\approx1) in normal state is twice that of the non-superconducting one (x0.85x\approx 0.85). The comparison of measured γn\gamma_n and the calculated electronic density of states (DOS) shows that the effective mass renormalization changes remarkably as the carbon concentration changes. The large mass renormalization for the superconducting sample and the low TcT_{c}(7K) indicate that more than one kind of boson mediated electron-electron interactions exist in MgCx_{x}Ni3_3.Comment: 4 pages, 4 figure

    Field-linked States of Ultracold Polar Molecules

    Full text link
    We explore the character of a novel set of ``field-linked'' states that were predicted in [A. V. Avdeenkov and J. L. Bohn, Phys. Rev. Lett. 90, 043006 (2003)]. These states exist at ultralow temperatures in the presence of an electrostatic field, and their properties are strongly dependent on the field's strength. We clarify the nature of these quasi-bound states by constructing their wave functions and determining their approximate quantum numbers. As the properties of field-linked states are strongly defined by anisotropic dipolar and Stark interactions, we construct adiabatic surfaces as functions of both the intermolecular distance and the angle that the intermolecular axis makes with the electric field. Within an adiabatic approximation we solve the 2-D Schrodinger equation to find bound states, whose energies correlate well with resonance features found in fully-converged multichannel scattering calculations
    corecore