613 research outputs found

    CULTURAL ROOTS OF TECHNOLOGY: AN INTERDISCIPLINARY STUDY OF AUTOMATED SYSTEMS FROM THE ANTIQUITY TO THE RENAISSANCE

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    The aim of this research work is to outline the history of proto-cybernetic systems throughout antiquity, Middle Ages and Renaissance. After identifying what are considered the main characteristics of an automaton, we examine all technical, literary, historical available sources, in order to get the descriptions not only of the actually built or designed automata, but also of the ones that were imagined in literary texts. From the work of historical reconstruction it has also been possible to make a classification of ancient automata, thanks to a UML representation of their operation. This classification of the types of automata and of the actions they could perform (or attributed to them) made it possible to build a matrix of distances of more than 200 automata (and of their features) with the Minkowski algorithm and consequently to get a philomemetic tree (with the software MEGA 4.0), which describes automata evolution over the period

    Una traduzione dell'Algebra di al-Khwarizmi nella Firenze del 14. secolo

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    This work presents the teaching of the solving technique for equations of the second degree described in the eighth century by al-Khwarizmi in his book Kitab al-hisab al-jabr w\u2019al-muqabalah; the aim is to outline its history not only in the Latin translation by Gerard of Cremona, but especially in a further Tuscan vernacular version (about 1390), preserved in a manuscript (Florence, Biblioteca Nazionale, II.III.198), which has never been studied before, but only quoted in two manuscripts catalogues by Mazzatinti and van Egmond, and in a book about algebra in 14th century by Boncompagni. The manuscript transcription is given here

    Goldstinos, Supercurrents and Metastable SUSY Breaking in N=2 Supersymmetric Gauge Theories

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    We construct an N=2 supersymmetric generalization of the N=1 supercurrent formalism of Komargodski and Seiberg (KS) and use it to show that N=2 theories with linear superconformal anomalies cannot break SUSY under certain broad assumptions. This result suggests that there are no metastable SUSY breaking vacua in a large class of theories that includes N=2 Super Yang-Mills (SYM).Comment: 19 pages; minor revisions; JHEP versio

    Fare didattica inclusiva con le ICT : la formazione dei docenti

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    I CTS-NTD (Centri Territoriali di Supporto - Nuove Tecnologie e Disabilit\ue0) sono scuole scelte dal MIUR per promuovere esperienze di didattica inclusiva con le ICT gi\ue0 realizzate sul territorio e per diffonderne la conoscenza in momenti di formazione destinati a docenti. Il Liceo Scientifico Statale Marconi, CTS-NTD di Milano, ha progettato tali attivit\ue0, attribuendo al concetto di inclusione un ambito pi\uf9 esteso, con l\u2019obiettivo di portare l\u2019abitudine all\u2019uso delle ICT dentro la prassi didattica quotidiana

    Positive Least Energy Solutions and Phase Separation for Coupled Schrodinger Equations with Critical Exponent: Higher Dimensional Case

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    We study the following nonlinear Schr\"{o}dinger system which is related to Bose-Einstein condensate: {displaymath} {cases}-\Delta u +\la_1 u = \mu_1 u^{2^\ast-1}+\beta u^{\frac{2^\ast}{2}-1}v^{\frac{2^\ast}{2}}, \quad x\in \Omega, -\Delta v +\la_2 v =\mu_2 v^{2^\ast-1}+\beta v^{\frac{2^\ast}{2}-1} u^{\frac{2^\ast}{2}}, \quad x\in \om, u\ge 0, v\ge 0 \,\,\hbox{in \om},\quad u=v=0 \,\,\hbox{on \partial\om}.{cases}{displaymath} Here \om\subset \R^N is a smooth bounded domain, 2∗:=2NN−22^\ast:=\frac{2N}{N-2} is the Sobolev critical exponent, -\la_1(\om)0 and ÎČ≠0\beta\neq 0, where \lambda_1(\om) is the first eigenvalue of −Δ-\Delta with the Dirichlet boundary condition. When \bb=0, this is just the well-known Brezis-Nirenberg problem. The special case N=4 was studied by the authors in (Arch. Ration. Mech. Anal. 205: 515-551, 2012). In this paper we consider {\it the higher dimensional case N≄5N\ge 5}. It is interesting that we can prove the existence of a positive least energy solution (u_\bb, v_\bb) {\it for any ÎČ≠0\beta\neq 0} (which can not hold in the special case N=4). We also study the limit behavior of (u_\bb, v_\bb) as ÎČ→−∞\beta\to -\infty and phase separation is expected. In particular, u_\bb-v_\bb will converge to {\it sign-changing solutions} of the Brezis-Nirenberg problem, provided N≄6N\ge 6. In case \la_1=\la_2, the classification of the least energy solutions is also studied. It turns out that some quite different phenomena appear comparing to the special case N=4.Comment: 48 pages. This is a revised version of arXiv:1209.2522v1 [math.AP

    The Hypermultiplet with Heisenberg Isometry in N=2 Global and Local Supersymmetry

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    The string coupling of N=2 supersymmetric compactifications of type II string theory on a Calabi-Yau manifold belongs to the so-called universal dilaton hypermultiplet, that has four real scalars living on a quaternion-Kaehler manifold. Requiring Heisenberg symmetry, which is a maximal subgroup of perturbative isometries, reduces the possible manifolds to a one-parameter family that describes the tree-level effective action deformed by the only possible perturbative correction arising at one-loop level. A similar argument can be made at the level of global supersymmetry where the scalar manifold is hyper-Kaehler. In this work, the connection between global and local supersymmetry is explicitly constructed, providing a non-trivial gravity decoupled limit of type II strings already in perturbation theory.Comment: 24 page

    Acoustic geometry for general relativistic barotropic irrotational fluid flow

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    "Acoustic spacetimes", in which techniques of differential geometry are used to investigate sound propagation in moving fluids, have attracted considerable attention over the last few decades. Most of the models currently considered in the literature are based on non-relativistic barotropic irrotational fluids, defined in a flat Newtonian background. The extension, first to special relativistic barotropic fluid flow, and then to general relativistic barotropic fluid flow in an arbitrary background, is less straightforward than it might at first appear. In this article we provide a pedagogical and simple derivation of the general relativistic "acoustic spacetime" in an arbitrary (d+1) dimensional curved-space background.Comment: V1: 23 pages, zero figures; V2: now 24 pages, some clarifications, 2 references added. This version accepted for publication in the New Journal of Physics. (Special issue on "Classical and Quantum Analogues for Gravitational Phenomena and Related Effects"

    Clinical Characteristics of Suicidal Youths and Adults: A One-Year Retrospective Study

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    Suicide is a major mental health problem, particularly during youth, when it is the second leading cause of death. Since young people at risk of suicide are often cared for by the adult health system, we sought to identify the specificities and similarities between suicidal youths and adults in order to further inform the potential need for adaptations in taking care of suicidal youths. For this study, we used the following data: mental disorders, treatments, previous hospitalization, and reasons for current hospitalization, that were collected from November 2016 to October 2017 among people hospitalized for a suicidal crisis in a specialized psychiatric unit. First, we compared the data from the youth group with those from the adult group, and then we tried to determine if there were any associations between variables. Analyses showed that youths were more similar to adults than expected. In particular, we found comparable rates of personality disorders (especially borderline) and relapse, and similar profiles of reasons for hospitalization in suicidal crisis. Remarkably, among youth, neuroleptics appeared to be associated with fewer hospitalizations for behavioral than ideational reasons, but with more relapses. Results of this study suggest that young people could benefit from brief psychotherapeutic interventions implemented for adult

    Stationary solutions of the nonlinear Schr\"odinger equation with fast-decay potentials concentrating around local maxima

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    We study positive bound states for the equation −ϔ2Δu+Vu=up,in RN,- \epsilon^2 \Delta u + Vu = u^p, \qquad \text{in $\mathbf{R}^N$}, where Ï”>0\epsilon > 0 is a real parameter, NN−2<p<N+2N−2\frac{N}{N-2} < p < \frac{N+2}{N-2} and VV is a nonnegative potential. Using purely variational techniques, we find solutions which concentrate at local maxima of the potential VV without any restriction on the potential.Comment: 25 pages, reformatted the abstract for MathJa

    First order Born-Infeld Hydrodynamics via Gauge/Gravity Duality

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    By performing a derivative expansion on a class of boosted Born-Infeld-AdS_5 black branes, we study the hydrodynamics of the dual field theory - in the spirit of AdS/CFT correspondence. We determine the fluid dynamical stress-energy tensor to first order, and find that the ratio of the shear viscosity to entropy density conforms to the universal value of 1/4π1/4\pi to all orders of the inverse of the Born-Infeld parameter.Comment: 14 pages, JHEP3, minor revision
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