866 research outputs found

    Identity, Life History and Commitment to Welfare

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    Using detailed extracts from two life histories, this article examines the nature of the personal identifications that often underpin the commitment of welfare workers to their jobs. We explore the paradox that it is those identifications such as class and gender, mediated through individual biography, that fix the ‘self as object’ and that also provide us with the resources for self-transformation. In this respect, the article not only throws light upon the psychical and emotional roots of commitment to the other, but also upon some of the impasses ‘identity theory’ currently finds itself in

    Vitexin as an active ingredient in passion flower with potential as an agent for nicotine cessation: Vitexin antagonism of the expression of nicotine locomotor sensitization in rats

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    Context: Nicotine, a bioactive component of tobacco, is highly addictive. Numerous therapies have been developed for smoking cessation, and all have met with limited success. Our laboratory has previously shown that an extract of Passiflora incarnata Linn. (Passifloraceae) antagonized the expression of nicotine locomotor sensitization in rats. Objective: This study examined the ability of vitexin, a flavonoid found in P. incarnata, to ameliorate the signs of nicotine sensitization in rats. Materials and methods: Male Wistar rats were administered 0.4 mg/kg nicotine or vehicle (n = 16–18 per group) once a day for four consecutive days. Nicotine administration produces sensitization of locomotor activity. On the fifth day, locomotor activity was monitored as rats from each treatment group were administered either 30 or 60 mg/kg vitexin or its vehicle (n = 4–6 per group) 30 min before a challenge dose of 0.4 mg/kg nicotine. Results: The challenge dose of nicotine resulted in locomotor activity in rats sensitized to nicotine for 4 days that was approximately twice that measured in rats treated with vehicle during the sensitization phase. Rats sensitized to nicotine and then treated with 60 mg/kg vitexin prior to the nicotine challenge exhibited a level of locomotor activity equivalent to the vehicle-treated controls. Discussion: Vitexin antagonized the expression of nicotine locomotor sensitization in rats as the whole extract did in the previous study. Conclusion: Vitexin should be examined in future studies to evaluate its potential for treating nicotine addiction in humans

    Robustness of a local Fermi Liquid against Ferromagnetism and Phase Separation

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    We study the properties of Fermi Liquids with the microscopic constraint of a local self-energy. In this case the forward scattering sum-rule imposes strong limitations on the Fermi-Liquid parameters, which rule out any Pomeranchek instabilities. For both attractive and repulsive interactions, ferromagnetism and phase separation are suppressed. Superconductivity is possible in an s-wave channel only. We also study the approach to the metal-insulator transition, and find a Wilson ratio approaching 2. This ratio and other properties of Sr_{1-x}La_xTiO_3 are all consistent with the local Fermi Liquid scenario.Comment: 4 pages (twocolumn format), can compile with or without epsf.sty latex style file -- Postscript files: fig1.ps and fig2.p

    Quasiparticle dynamics and phonon softening in FeSe superconductors

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    Quasiparticle dynamics of FeSe single crystals revealed by dual-color transient reflectivity measurements ({\Delta}R/R) provides unprecedented information on Fe-based superconductors. The amplitude of fast component in {\Delta}R/R clearly tells a competing scenario between spin fluctuations and superconductivity. Together with the transport measurements, the relaxation time analysis further exhibits anomalous changes at 90 K and 230 K. The former manifests a structure phase transition as well as the associated phonon softening. The latter suggests a previously overlooked phase transition or crossover in FeSe. The electron-phonon coupling constant {\lambda} is found to be 0.16, identical to the value of theoretical calculations. Such a small {\lambda} demonstrates an unconventional origin of superconductivity in FeSe.Comment: Final published version; 5 pages; 4 figure

    Acoustic attenuation rate in the Fermi-Bose model with a finite-range fermion-fermion interaction

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    We study the acoustic attenuation rate in the Fermi-Bose model describing a mixtures of bosonic and fermionic atom gases. We demonstrate the dramatic change of the acoustic attenuation rate as the fermionic component is evolved through the BEC-BCS crossover, in the context of a mean-field model applied to a finite-range fermion-fermion interaction at zero temperature, such as discussed previously by M.M. Parish et al. [Phys. Rev. B 71, 064513 (2005)] and B. Mihaila et al. [Phys. Rev. Lett. 95, 090402 (2005)]. The shape of the acoustic attenuation rate as a function of the boson energy represents a signature for superfluidity in the fermionic component

    Highlighting the Mechanistic Relationship Between Perinatal Depression and Preeclampsia: A Scoping Review

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    Background: Although there is scientific literature supporting an association between depression and preeclampsia (PE), little is known about the underlying mechanistic pathways that may explain these observed associations. Thus, this study aimed to outline the relationship between depression and PE, and to highlight the underlying cardiovascular and metabolic risk factors that are common to both. Methods: A scoping review of the literature was conducted in Medline, Scopus, and Web of Science. Results: From 706 articles initially identified, 23 articles met the inclusion criteria and were included in this review. Although some studies reported a positive association between PE and postpartum depressive symptoms, challenges comparing different methodologies, measurement instruments and when measurements were administered, and patient populations do not permit a decisive conclusion. In addition, very few studies addressed potential underlying mechanisms that may be contributing to observed associations; thus, a secondary search was conducted to identify cardiovascular and metabolic risk factors that are common to both depression and PE. Conclusion: The cardiovascular and metabolic risk factors (i.e., increased inflammation and oxidative stress and decreased vascular and endothelial function) common to both depression and PE suggest that these factors may contribute as underlying mechanisms in both conditions. These similarities underscore the importance to better understand these mechanisms so preventative and therapeutic strategies could be developed to improve maternal health

    18 Sco: a solar twin rich in refractory and neutron-capture elements. Implications for chemical tagging

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    We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high resolution (R ~ 110 000) high S/N (800-1000) VLT UVES spectra, which allow us to achieve a precision of about 0.005 dex in differential abundances. The effective temperature and surface gravity of 18 Sco are Teff = 5823+/-6 K and log g = 4.45+/-0.02 dex, i.e., 18 Sco is 46+/-6 K hotter than the Sun and log g is 0.01+/-0.02 dex higher. Its metallicity is [Fe/H] = 0.054+/-0.005 dex and its microturbulence velocity is +0.02+/-0.01 km/s higher than solar. Our precise stellar parameters and differential isochrone analysis show that 18 Sco has a mass of 1.04+/-0.02M_Sun and that it is ~1.6 Gyr younger than the Sun. We use precise HARPS radial velocities to search for planets, but none were detected. The chemical abundance pattern of 18 Sco displays a clear trend with condensation temperature, showing thus higher abundances of refractories in 18 Sco than in the Sun. Intriguingly, there are enhancements in the neutron-capture elements relative to the Sun. Despite the small element-to-element abundance differences among nearby n-capture elements (~0.02 dex), we successfully reproduce the r-process pattern in the solar system. This is independent evidence for the universality of the r-process. Our results have important implications for chemical tagging in our Galaxy and nucleosynthesis in general.Comment: ApJ, in pres

    Thermoelectric Figure of Merit of Strongly Correlated Superlattice Semiconductors

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    We solved the Anderson Lattice Hamiltonian to get the energy bands of a strongly correlated semiconductor by using slave boson mean field theory. The transport properties were calculated in the relaxation-time approximation,and the thermoelectric figure of merit was obtained for the strongly correlated semiconductor and its superlattice structures. We found that at room temperature ZTZT can reach nearly 2 for the quantum wire lattice structure.We believe that it is possible to find high values of thermoelectric figure of merit from strongly correlated semiconductor superlattice systems.Comment: 4 pages, 3 figure
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