6,558 research outputs found
Like grandparents, like parents: Empirical evidence and psychoanalytic thinking on the transmission of parenting styles
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
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
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
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 .
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
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
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
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
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
, and on the (possibly asymmetric) norm defined in
. In the special case when 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
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 (θn∼3Hz) són molt adequats per a l'estudi de fenòmens transitoris. En aquest treball presenten en primer lloc resultats relatius a la transformació β → γ' de l'aliatge Cu-
Zn-Al. La transformació presenta un caràcter molt discontinu, una dissipació energètica important, i una excellent 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 (θn∼3Hz) allow the study of structural transformations in solids. We present results concerning the martensitic transformation β → γ' 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 of antiproton annihilation at rest at three hydrogen target densities
The proton-antiproton annihilation at rest into the 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 channel were calculated on the basis of
simultaneous analysis of the three data samples. The branching ratio for
annihilation into from the protonium state turns out to be
about ten times smaller as compared to the one from the state.Comment: 10 pages, 3 Postscript figures. Accepted by Physics Letters
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