1,385 research outputs found

    Nuclear structure study around Z=28

    Full text link
    Yrast levels of Ni, Cu and Zn isotopes for 40≤N≤5040 \leq N \leq50 have been described by state-of-the-art shell model calculations with three recently available interactions using 56^{56}Ni as a core in the f5/2pg9/2f_{5/2}pg_{9/2} model space. The results are unsatisfactory viz. large E(2+)E(2^+) for very neutron rich nuclei, small B(E2) values in comparison to experimental values. These results indicate an importance of inclusion of πf7/2\pi f_{7/2} and νd5/2\nu d_{5/2} orbitals in the model space to reproduce collectivity in this region.Comment: 12 pages, 14 figure

    Parametric Generation of Second Sound by First Sound in Superfluid Helium

    Full text link
    We report the first experimental observation of parametric generation of second sound (SS) by first sound (FS) in superfluid helium in a narrow temperature range in the vicinity of TλT_\lambda . The temperature dependence of the threshold FS amplitude is found to be in a good quantitative agreement with the theory suggested long time ago and corrected for a finite geometry. Strong amplitude fluctuations and two types of the SS spectra are observed above the bifurcation. The latter effect is quantitatively explained by the discreteness of the wave vector space and the strong temperature dependence of the SS dissipation length.Comment: 4 pages, 4 postscript figures, REVTE

    Low-Temperature Mobility of Surface Electrons and Ripplon-Phonon Interaction in Liquid Helium

    Full text link
    The low-temperature dc mobility of the two-dimensional electron system localized above the surface of superfluid helium is determined by the slowest stage of the longitudinal momentum transfer to the bulk liquid, namely, by the interaction of surface and volume excitations of liquid helium, which rapidly decreases with temperature. Thus, the temperature dependence of the low-frequency mobility is \mu_{dc} = 8.4x10^{-11}n_e T^{-20/3} cm^4 K^{20/3}/(V s), where n_e is the surface electron density. The relation T^{20/3}E_\perp^{-3} << 2x10^{-7} between the pressing electric field (in kV/cm) and temperature (in K) and the value \omega < 10^8 T^5 K^{-5}s^{-1} of the driving-field frequency have been obtained, at which the above effect can be observed. In particular, E_\perp = 1 kV/cm corresponds to T < 70 mK and \omega/2\pi < 30 Hz.Comment: 4 pages, 1 figur

    Depression and Oral FTC/TDF Pre-exposure Prophylaxis (PrEP) Among Men and Transgender Women Who Have Sex With Men (MSM/TGW).

    Get PDF
    We conducted a longitudinal and cross-sectional analysis of depressive symptomology in iPrEx, a randomized, placebo-controlled trial of daily, oral FTC/TDF HIV pre-exposure prophylaxis (PrEP) in men and transgender women who have sex with men. Depression-related adverse events (AEs) were the most frequently reported severe or life-threatening AEs and were not associated with being randomized to the FTC/TDF arm (152 vs. 144 respectively OR 0.66 95&nbsp;% CI 0.35-1.25). Center for Epidemiologic Studies Depression scale (CES-D) and a four questions suicidal ideation scale scores did not differ by arm. Participants reporting forced sex at anal sexual debut had higher CES-D scores (coeff: 3.23; 95&nbsp;% CI 1.24-5.23) and were more likely to have suicidal ideation (OR 2.2; 95&nbsp;% CI 1.09-4.26). CES-D scores were higher among people reporting non-condom receptive anal intercourse (ncRAI) (OR 1.46; 95&nbsp;% CI 1.09-1.94). We recommend continuing PrEP during periods of depression in conjunction with provision of mental health services

    Large scale shell model calculations for odd-odd 58−62^{58-62}Mn isotopes

    Full text link
    Large scale shell model calculations have been carried out for odd-odd 58−62^{58-62}Mn isotopes in two different model spaces. First set of calculations have been carried out in full fp\it{fp} shell valence space with two recently derived fp\it{fp} shell interactions namely GXPF1A and KB3G treating 40^{40}Ca as core. The second set of calculations have been performed in fpg9/2{fpg_{9/2}} valence space with the fpgfpg interaction treating 48^{48}Ca as core and imposing a truncation by allowing up to a total of six particle excitations from the 0f7/2_{7/2} orbital to the upper fp\it{fp} orbitals for protons and from the upper fp\it{fp} orbitals to the 0g9/2_{9/2} orbital for neutron. For low-lying states in 58^{58}Mn, the KB3G and GXPF1A both predicts good results and for 60^{60}Mn, KB3G is much better than GXPF1A. For negative parity and high-spin positive parity states in both isotopes fpgfpg interaction is required. Experimental data on 62^{62}Mn is sparse and therefore it is not possible to make any definite conclusions. More experimental data on negative parity states is needed to ascertain the importance of 0g9/2_{9/2} and higher orbitals in neutron rich Mn isotopes.Comment: 5 pages, 4 figures, Submitted to Eur. Phys. J.
    • …
    corecore