613 research outputs found
CULTURAL ROOTS OF TECHNOLOGY: AN INTERDISCIPLINARY STUDY OF AUTOMATED SYSTEMS FROM THE ANTIQUITY TO THE RENAISSANCE
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
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
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
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
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, is the Sobolev critical
exponent, -\la_1(\om)0 and , where
\lambda_1(\om) is the first eigenvalue of 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 }. It is interesting that we can prove the existence
of a positive least energy solution (u_\bb, v_\bb) {\it for any } (which can not hold in the special case N=4). We also study the limit
behavior of (u_\bb, v_\bb) as and phase separation is
expected. In particular, u_\bb-v_\bb will converge to {\it sign-changing
solutions} of the Brezis-Nirenberg problem, provided . 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
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
"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
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
We study positive bound states for the equation where is a real
parameter, and is a nonnegative
potential. Using purely variational techniques, we find solutions which
concentrate at local maxima of the potential without any restriction on the
potential.Comment: 25 pages, reformatted the abstract for MathJa
First order Born-Infeld Hydrodynamics via Gauge/Gravity Duality
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 to all
orders of the inverse of the Born-Infeld parameter.Comment: 14 pages, JHEP3, minor revision
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