130 research outputs found

    Variations of Gender Gaps in the Labour Market Outcomes of Graduates across Fields of Study: A (Combined) Test of Two Theories

    Get PDF
    Unequal gender outcomes in occupational success unravel through different channels in higher education. Using the AlmaLaurea dataset comprised of 80% of Italian graduates and 98 fields of study, this article investigates whether men and women receive similar returns on employment and earnings when choosing the same field of study. Two complementary perspectives are applied - Kanter's theory of relative numbers and the status theory of gender - to examine the quantitative and qualitative differences between fields. The results show that the most gender 'balanced' fields of study are the most gender unequal in terms of earnings and employment. Separate analyses demonstrate that the status of a field interacts with its gender composition, and gender gaps in female-intensive nurturing fields shrink faster with an increasing proportion of women, albeit at higher absolute levels compared with non-nurturing fields. Therefore, nurturing fields of study should not necessarily be considered as levelling gender inequality in the labour market

    Electron-phonon vertex in the two-dimensional one-band Hubbard model

    Full text link
    Using quantum Monte Carlo techniques, we study the effects of electronic correlations on the effective electron-phonon (el-ph) coupling in a two-dimensional one-band Hubbard model. We consider a momentum-independent bare ionic el-ph coupling. In the weak- and intermediate-correlation regimes, we find that the on-site Coulomb interaction UU acts to effectively suppress the ionic el-ph coupling at all electron- and phonon- momenta. In this regime, our numerical simulations are in good agreement with the results of perturbation theory to order U2U^2. However, entering the strong-correlation regime, we find that the forward scattering process stops decreasing and begins to substantially increase as a function of UU, leading to an effective el-ph coupling which is peaked in the forward direction. Whereas at weak and intermediate Coulomb interactions, screening is the dominant correlation effect suppressing the el-ph coupling, at larger UU values irreducible vertex corrections become more important and give rise to this increase. These vertex corrections depend crucially on the renormalized electronic structure of the strongly correlated system.Comment: 5 pages, 4 eps-figures, minor change

    Interplay of Electron-Phonon Interaction and Electron Correlation in High Temperature Superconductivity

    Get PDF
    We study the electron-phonon interaction in the strongly correlated superconducting cuprates. Two types of the electron-phonon interactions are introduced in the t−Jt-J model; the diagonal and off-diagonal interactions which modify the formation energy of the Zhang-Rice singlet and its transfer integral, respectively. The characteristic phonon-momentum (q⃗)(\vec q) and electron-momentum (k⃗)(\vec k) dependence resulted from the off-diagonal coupling can explain a variety of experiments. The vertex correction for the electron-phonon interaction is formulated in the SU(2) slave-boson theory by taking into account the collective modes in the superconducting ground states. It is shown that the vertex correction enhances the attractive potential for the d-wave paring mediated by phonon with q⃗=(π(1−ή),0)\vec q=(\pi(1-\delta), 0) around ή≅0.3\delta \cong 0.3 which corresponds to the half-breathing mode of the oxygen motion.Comment: 14 pages, 13 figure

    Effect of an Electron-phonon Interaction on the One-electron Spectral Weight of a d-wave Superconductor

    Full text link
    We analyze the effects of an electron-phonon interaction on the one-electron spectral weight A(k,omega) of a d_{x^2-y^2} superconductor. We study the case of an Einstein phonon mode with various momentum-dependent electron-phonon couplings and compare the structure produced in A(k,omega) with that obtained from coupling to the magnetic pi-resonant mode. We find that if the strength of the interactions are adjusted to give the same renormalization at the nodal point, the differences in A(k,omega) are generally small but possibly observable near k=(pi,0).Comment: 10 pages, 14 figures (color versions of Figs. 2,4,10,11,12 available upon request

    Stochastic pump effect and geometric phases in dissipative and stochastic systems

    Full text link
    The success of Berry phases in quantum mechanics stimulated the study of similar phenomena in other areas of physics, including the theory of living cell locomotion and motion of patterns in nonlinear media. More recently, geometric phases have been applied to systems operating in a strongly stochastic environment, such as molecular motors. We discuss such geometric effects in purely classical dissipative stochastic systems and their role in the theory of the stochastic pump effect (SPE).Comment: Review. 35 pages. J. Phys. A: Math, Theor. (in press

    Tunneling spectroscopy in the magnetic superconductor TmNi2B2C

    Full text link
    We present new measurements about the tunneling conductance in the borocarbide superconductor TmNi2_2B2_2C. The results show a very good agreement with weak coupling BCS theory, without any lifetime broadening parameter, over the whole sample surface. We detect no particular change of the tunneling spectroscopy below 1.5K, when both the antiferromagnetic (AF) phase and the superconducting order coexist.Comment: Submitted to Phys. Rev. B, Rapid Communication

    Post-ischaemic silencing of p66Shc reduces ischaemia/reperfusion brain injury and its expression correlates to clinical outcome in stroke

    Get PDF
    In light of the limited repertoire of therapeutical options available for the treatment of ischaemic stroke, the identification of novel potential targets is vital; in this respect, the present study demonstrates that the adaptor protein p66Shc holds this potential as an adjunct therapy to thrombolysis. Post-ischaemic silencing of p66Shc protein yielded beneficial effects in a mouse model of I/R brain injury underlying an interesting translational perspective for this target protein. Further, in proof-of-principle clinical experiments using PBMs, we demonstrate that p66Shc gene expression is transiently increased and that its levels correlate to short-term outcome in ischaemic stroke patients. Although these latter experiments are not directly relevant to the experiments performed in mice and in human endothelial cells, they provide novel important information about p66Shc regulation in stroke patients and set the basis for further investigations aimed at assessing the potential for p66Shc to become a novel therapeutic target as an adjunct of thrombolysis for the management of acute ischaemic strok

    Bidirectional lipid droplet velocities are controlled by differential binding strengths of HCV Core DII protein

    Get PDF
    Host cell lipid droplets (LD) are essential in the hepatitis C virus (HCV) life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein’s lipid binding domain II (DII-core) induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV

    Superconductivity in Fullerides

    Full text link
    Experimental studies of superconductivity properties of fullerides are briefly reviewed. Theoretical calculations of the electron-phonon coupling, in particular for the intramolecular phonons, are discussed extensively. The calculations are compared with coupling constants deduced from a number of different experimental techniques. It is discussed why the A_3 C_60 are not Mott-Hubbard insulators, in spite of the large Coulomb interaction. Estimates of the Coulomb pseudopotential Ό∗\mu^*, describing the effect of the Coulomb repulsion on the superconductivity, as well as possible electronic mechanisms for the superconductivity are reviewed. The calculation of various properties within the Migdal-Eliashberg theory and attempts to go beyond this theory are described.Comment: 33 pages, latex2e, revtex using rmp style, 15 figures, submitted to Review of Modern Physics, more information at http://radix2.mpi-stuttgart.mpg.de/fullerene/fullerene.htm
    • 

    corecore