9,332 research outputs found

    Multiplicity of layered solutions for Allen-Cahn systems with symmetric double well potential

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    We study the existence of solutions u:R3→R2u:\R^{3}\to\R^{2} for the semilinear elliptic systems \begin{equation}\label{eq:abs} -\Delta u(x,y,z)+\nabla W(u(x,y,z))=0, \end{equation} where W:R2→RW:\R^{2}\to\R is a double well symmetric potential. We use variational methods to show, under generic non degenerate properties of the set of one dimensional heteroclinic connections between the two minima \a_{\pm} of WW, that (\ref{eq:abs}) has infinitely many geometrically distinct solutions u∈C2(R3,R2)u\in C^{2}(\R^{3},\R^{2}) which satisfy u(x,y,z)\to \a_{\pm} as x→±∞{x\to\pm\infty} uniformly with respect to (y,z)∈R2(y,z)\in\R^{2} and which exhibit dihedral symmetries with respect to the variables yy and zz. We also characterize the asymptotic behaviour of these solutions as ∣(y,z)∣→+∞|(y,z)|\to +\infty

    Determination of continuous variable entanglement by purity measurements

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    We classify the entanglement of two--mode Gaussian states according to their degree of total and partial mixedness. We derive exact bounds that determine maximally and minimally entangled states for fixed global and marginal purities. This characterization allows for an experimentally reliable estimate of continuous variable entanglement based on measurements of purity.Comment: 4 pages, 3 EPS figures. Final versio

    Quaternionic spherical harmonics and a sharp multiplier theorem on quaternionic spheres

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    A sharp LpL^p spectral multiplier theorem of Mihlin--H\"ormander type is proved for a distinguished sub-Laplacian on quaternionic spheres. This is the first such result on compact sub-Riemannian manifolds where the horizontal space has corank greater than one. The proof hinges on the analysis of the quaternionic spherical harmonic decomposition, of which we present an elementary derivation

    Firing costs and the business cycle: Policy implications in light of the financial crisis.

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    This lecture is a tour dhorizon of the financial crisis aimed at extracting lessons for future financial regulation. It combines normative recommendations based on conventional welfare economics with positive assessments of the kind of measures likely to be adopted based on political economy considerations.Konjunktur; Kündigung; Arbeitsmobilität; Kosten; Währungsunion; Arbeitnehmerschutz;

    An Incentive Theory of Matching

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    This paper presents a theory explaining the labor market matching process through microeconomic incentives. There are heterogeneous variations in the characteristics of workers and jobs, and firms face adjustment costs in responding to these variations. Matches and separations are described through firms' job offer and firing decisions and workers' job acceptance and quit decisions. This approach obviates the need for a matching function. On this theoretical basis, we argue that the matching function is vulnerable to the Lucas critique. Our calibrated model for the U.S. economy can account for important empirical regularities that the conventional matching model cannot.matching, incentives, adjustment costs, unemployment, employment, quits, firing, job offers, job acceptance

    Mothers and fathers with Binge Eating Disorder and their 18-36 months old children: a longitudinal study on parent-infant interactions and offspring\u2019s emotional-behavioral profiles

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    Maternal Binge Eating Disorder (BED) has been suggested to be associated with poor parent\u2013infant interactions during feeding and with children\u2019s emotional and behavioral problems during infancy (Blissett and Haycraft, 2011). The role of fathers has received increasing consideration in recent years, yet the research has not focused on interactional patterns between fathers with BED and their children. The present study aimed to longitudinally investigate the in\ufb02uence of BED diagnosis, in one or both parents, on parent\u2013infant feeding interactions and on children\u2019s emotional\u2013behavioral functioning. 612 subjects (408 parents; 204 children), recruited in mental health services and pre-schools in Central Italy, were divided into four groups: Group 1 included families with both parents diagnosed with BED, Group 2 and 3 included families with one parent diagnosed with BED, Group 0 was a healthy control. The assessment took place at T1 (18 months of age of children) and T2 (36 months of age of children): feeding interactions were assessed through the Scale for the Assessment of Feeding Interactions (SVIA) while child emotional\u2013behavioral functioning was evaluated with the Child Behavior Check-List (CBCL). When compared to healthy controls, the groups with one or both parents diagnosed with BED showed higher scores on the SVIA and on the CBCL internalizing and externalizing scales, indicating poorer adult\u2013child feeding interactions and higher emotional\u2013behavioral dif\ufb01culties. A direct in\ufb02uence of parental psychiatric diagnosis on the quality of mother\u2013infant and father\u2013infant interactions was also found, both at T1 and T2. Moreover, dyadic feeding interactions mediated the in\ufb02uence of parental diagnosis on children\u2019s psychological functioning. The presence of BED diagnosis in one or both parents seems to in\ufb02uence the severity of maladaptive parent\u2013infant exchanges during feeding and offspring\u2019s emotional\u2013behavioral problems over time, consequently affecting different areas of children\u2019s psychological functioning. This is the \ufb01rst study to demonstrate the speci\ufb01c effects of maternal and paternal BED on infant development. These results could inform prevention and intervention programs in families with one or both parents diagnosed with BED

    Quantum cooling and squeezing of a levitating nanosphere via time-continuous measurements

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    With the purpose of controlling the steady state of a dielectric nanosphere levitated within an optical cavity, we study its conditional dynamics under simultaneous sideband cooling and additional time-continuous measurement of either the output cavity mode or the nanosphere's position. We find that the average phonon number, purity and quantum squeezing of the steady-states can all be made more non-classical through the addition of time-continuous measurement. We predict that the continuous monitoring of the system, together with Markovian feedback, allows one to stabilize the dynamics for any value of the laser frequency driving the cavity. By considering state-of-the-art values of the experimental parameters, we prove that one can in principle obtain a non-classical (squeezed) steady-state with an average phonon number nph≈0.5n_{\sf ph}\approx 0.5.Comment: 10 pages, 9 figures; v2: close to published versio

    Orofacial muscles activity in children with swallowing dysfunction and removable functional appliances

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    Swallowing dysfunction is a frequent disorder among children and refers to an altered tongue posture and abnormal tongue movement during swallowing. Removable functional appliance is one of the treatments applied by dentistry to correct this disorder. The aim of this study was to evaluate any differences on orofacial muscles activity in children with swallowing dysfunction with and without removable functional appliances. 68 children were eligible for the study and divided into the orthodontic group (OG) and the no-orthodontic group (NO-OG). Both groups performed a dental occlusion-class evaluation, a swallowing function test and a myoscan analysis in order to measure perioral forces (i.e. tongue extension force, lip pressure, masseter contraction force). Our results showed a significant difference (P=0.02) between OG and NO-OG for the tongue extension force, whereas no significant differences (P>0.05) were found for the other parameters. Our findings suggest that children with swallowing dysfunction and removable functional appliance show orofacial muscles activity within the range of reference values (except for the lip pressure). However, we hypothesize that orthodontic treatment can achieve more effective results with integration of myofunctional therapy

    Confining properties of QCD at finite temperature and density

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    A disorder parameter detecting dual superconductivty of the vacuum is used as a probe to characterize the confining properties of the phase diagram of two color QCD at finite temperature and density. We obtain evidence for the disappearing of dual superconductivity (deconfinement) induced by a finite density of baryonic matter, as well as for a coincidence of this phenomenon with the restoration of chiral symmetry both at zero and finite density. The saturation transition induced by Pauli blocking is studied as well, and a general warning is given about the possible effects that this unphysical transition could have on the study of the QCD phase diagram at strong values of the gauge coupling.Comment: 13 pages, 23 figure
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