6,558 research outputs found

    Like grandparents, like parents: Empirical evidence and psychoanalytic thinking on the transmission of parenting styles

    Get PDF
    The authors discuss the issue of intergenerational transmission of parenting from an empirical and psychoanalytic perspective. After presenting a framework to explain their conception of parenting, they describe intergenerational transmission of parenting as a key to interpreting and eventually changing parenting behaviors. Then they present (1) the empirical approach aimed at determining if there is actually a stability across generations that contributes to harsh parenting and eventually maltreatment and (2) the psyphoanalytic thinking that seeks to explain the continuity in terms of representations and clinical phenomena. The authors also discuss the relationship between the attachment and the caregiving systems and hypothesize a common base for the two systems in childhood experience. Finally, they propose the psychoanalytic perspective as a fruitful theoretical framework to integrate the evidence for the neurophysiological mediators and moderators of intergenerational transmission. Psychoanalytically informed research can provide clinically relevant insights and hypotheses to be tested

    Scalar fields on SL(2,R) and H^2 x R geometric spacetimes and linear perturbations

    Full text link
    Using appropriate harmonics, we study the future asymptotic behavior of massless scalar fields on a class of cosmological vacuum spacetimes. The spatial manifold is assumed to be a circle bundle over a higher genus surface with a locally homogeneous metric. Such a manifold corresponds to the SL(2,R)-geometry (Bianchi VIII type) or the H^2 x R-geometry (Bianchi III type). After a technical preparation including an introduction of suitable harmonics for the circle-fibered Bianchi VIII to separate variables, we derive systems of ordinary differential equations for the scalar field. We present future asymptotic solutions for these equations in a special case, and find that there is a close similarity with those on the circle-fibered Bianchi III spacetime. We discuss implications of this similarity, especially to (gravitational) linear perturbations. We also point out that this similarity can be explained by the "fiber term dominated behavior" of the two models.Comment: 23 pages, no figures, to be published in Class. Quant. Gravi

    Prediction of minimum temperatures in an alpine region by linear and non-linear post-processing of meteorological models

    No full text
    International audienceModel Output Statistics (MOS) refers to a method of post-processing the direct outputs of numerical weather prediction (NWP) models in order to reduce the biases introduced by a coarse horizontal resolution. This technique is especially useful in orographically complex regions, where large differences can be found between the NWP elevation model and the true orography. This study carries out a comparison of linear and non-linear MOS methods, aimed at the prediction of minimum temperatures in a fruit-growing region of the Italian Alps, based on the output of two different NWPs (ECMWF T511?L60 and LAMI-3). Temperature, of course, is a particularly important NWP output; among other roles it drives the local frost forecast, which is of great interest to agriculture. The mechanisms of cold air drainage, a distinctive aspect of mountain environments, are often unsatisfactorily captured by global circulation models. The simplest post-processing technique applied in this work was a correction for the mean bias, assessed at individual model grid points. We also implemented a multivariate linear regression on the output at the grid points surrounding the target area, and two non-linear models based on machine learning techniques: Neural Networks and Random Forest. We compare the performance of all these techniques on four different NWP data sets. Downscaling the temperatures clearly improved the temperature forecasts with respect to the raw NWP output, and also with respect to the basic mean bias correction. Multivariate methods generally yielded better results, but the advantage of using non-linear algorithms was small if not negligible. RF, the best performing method, was implemented on ECMWF prognostic output at 06:00 UTC over the 9 grid points surrounding the target area. Mean absolute errors in the prediction of 2 m temperature at 06:00 UTC were approximately 1.2°C, close to the natural variability inside the area itself

    Premartensitic transition driven by magnetoelastic interaction in bcc ferromagnetic Ni2MnGaNi_{2}MnGa

    Get PDF
    We show that the magnetoelastic coupling between the magnetization and the amplitude of a short wavelength phonon enables the existence of a first order premartensitic transition from a bcc to a micromodulated phase in Ni2MnGaNi_{2}MnGa. Such a magnetoelastic coupling has been experimentally evidenced by AC susceptibility and ultrasonic measurements under applied magnetic field. A latent heat around 9 J/mol has been measured using a highly sensitive calorimeter. This value is in very good agreement with the value predicted by a proposed model.Comment: 4 pages RevTex, 3 Postscript figures, to be published in Physical Review Letter

    Spin-coherent dynamics and carrier lifetime in strained Ge1−xSnx semiconductors on silicon

    Get PDF
    We demonstrate an effective epitaxial route for the manipulation and further enrichment of the intriguing spin-dependent phenomena boasted by germanium. We show optical initialization and readout of spins in Ge-rich germanium-tin alloys and report on spin quantum beats between Zeeman-split levels under an external magnetic field. While heavy Sn atoms can be readily utilized to strengthen the spin-orbit coupling, our experiments reveal robust spin orientation in a wide temperature range and a persistent spin lifetime that noticeably approaches the nanosecond regime at room temperature. In addition, time decay photoluminescence experiments evidence a temperature-induced monotonic decrease of the carrier lifetime, eventually providing crucial insights also into nonradiative recombination mechanisms

    General behaviour of Bianchi VI_0 solutions with an exponential-potential scalar field

    Get PDF
    The solutions to the Einstein-Klein-Gordon equations without a cosmological constant are investigated for an exponential potential in a Bianchi VI_0 metric. There exists a two-parameter family of solutions which have a power-law inflationary behaviour when the exponent of the potential, k, satisfies k^2<2. In addition, there exists a two-parameter family of singular solutions for all k^2 values. A simple anisotropic exact solution is found to be stable when 2<k^2.Comment: 10 pages, no figures. To be published in General Relativity and Gravitatio

    Stability of inflationary solutions driven by a changing dissipative fluid

    Get PDF
    In this paper the second Lyapunov method is used to study the stability of the de Sitter phase of cosmic expansion when the source of the gravitational field is a viscous fluid. Different inflationary scenarios related with reheating and decay of mini-blackholes into radiation are investigated using an effective fluid described by time--varying thermodynamical quantities.Comment: 17 pages, LaTeX 2.09, 2 figures. To be published in Classical and Quantum Gravit

    A nonhomogeneous boundary value problem in mass transfer theory

    Full text link
    We prove a uniqueness result of solutions for a system of PDEs of Monge-Kantorovich type arising in problems of mass transfer theory. The results are obtained under very mild regularity assumptions both on the reference set ΩRn\Omega\subset\mathbf{R}^n, and on the (possibly asymmetric) norm defined in Ω\Omega. In the special case when Ω\Omega is endowed with the Euclidean metric, our results provide a complete description of the stationary solutions to the tray table problem in granular matter theory.Comment: 22 pages, 2 figure

    La Termogènesi als calorímetres per conducció: les transformacions sòlid-sòlid i les barreges líquides

    Get PDF
    Descrivim alguns mètodes d'obtenció de funcions de transferència associades a fenòmens reals i donem exemples de les termogènesis obtingudes en aquests casos. Els calorimètres amb molt bones característiques dinàmiques (&theta;n&sim;3Hz) són molt adequats per a l'estudi de fenòmens transitoris. En aquest treball presenten en primer lloc resultats relatius a la transformació &beta; &rarr; &gamma;' de l'aliatge Cu- Zn-Al. La transformació presenta un caràcter molt discontinu, una dissipació energètica important, i una excel•lent correlació amb l'emissió acústica generada durant el procés de transformació que permet donar una valoració qualitativa de les possibilitats calorimètriques de l'anàlisi entàlpica diferencial. En segon lloc presentem una anàlisi de les entalpies d'excés en les barreges líquides. Aquest estudi és molt interessant a baixes concentracions. L'ús de sistemes d'injecció permet assolir fraccions molars de solut xs\gtrsim 0.01. L'obtenció d'una funció de transferència correcta del sistema calorimètric i l'ús d'algorismes deconvolutius eficaços permet reduir la fracció molar a xs\gtrsim 0.001.This paper presents several methods to obtain transfer functions associated with power dissipations in actual phenomena and a few examples of the approximate thermogenesis obtained. On the one hand, calorimeters with extremely good dynamic characteristics (&theta;n&sim;3Hz) allow the study of structural transformations in solids. We present results concerning the martensitic transformation &beta; &rarr; &gamma;' of a Cu-Zn-Al alloy. They show the jerky character of the transformation very well correlated with acoustic emission patterns and an important energy 1iberation. This analysis gives an estimate of the posibilities of calorimetry within the field of Differential Enthalpic Analysis. On the other hand, an analysis of the properties of liquid mixtures at low concentrations is very interesting when carried out their excess enthalpies. Steady injection systems allow to reach solute molar fractions xs\gtrsim 0.01. We describe here the obtention of a correct transfer function. Now, the application of proper deconvolutive algorithms make it possible to work at so low concentrations as xs\gtrsim 0.001

    Measurements of the reaction pˉpϕη\bar{p}p \to \phi \eta of antiproton annihilation at rest at three hydrogen target densities

    Full text link
    The proton-antiproton annihilation at rest into the ϕη\phi\eta final state was measured for three different target densities: liquid hydrogen, gaseous hydrogen at NTP and at a low pressure of 5 mbar. The yield of this reaction in the liquid hydrogen target is smaller than in the low-pressure gas target. The branching ratios of the ϕη\phi\eta channel were calculated on the basis of simultaneous analysis of the three data samples. The branching ratio for annihilation into ϕη\phi\eta from the 3S1^3S_1 protonium state turns out to be about ten times smaller as compared to the one from the 1P1^1P_1 state.Comment: 10 pages, 3 Postscript figures. Accepted by Physics Letters
    corecore