Décroche pas !: comment comprendre le "décrochage scolaire" et de formation comme un processus dynamique interactif, un enjeu de société majeur et une source de souffrance : travail de Bachelor effectué dans le cadre de la formation à la Haute école de travail social de Genève

Ce travail de Bachelor a été distingué par le Prix d'encouragement 2014 de la Fondation Qualife pour l’insertion des jeunes et jeunes adultes en difficulté. Le « décrochage scolaire » ou de formation est un sujet qui est au coeur de notre actualité sociale et politique. Cette problématique a mobilisé, ces dernières années à Genève, beaucoup d’efforts tant de la part des politiques que des professionnels. L’offre de dispositifs s’est considérablement densifiée et diversifiée, et il n’est pas toujours facile, tant pour les professionnels que pour les jeunes et leurs parents, de s’y retrouver. Nous sommes actuellement dans une période charnière de cette évolution avec l’inscription dans la Constitution genevoise de la formation obligatoire jusqu’à 18 ans. Un des objectifs de ce changement étant d’augmenter le nombre de jeunes obtenant une certification de degré secondaire 2. Face à ces attentes et cette forte mobilisation de la société, nous avons voulu mieux comprendre les enjeux de la prise en charge du « décrochage ». Car, s’il existe un vaste panel d’accompagnement, les jeunes en situation de « décrochage » continuent à interroger et surtout à confronter les professionnels à leurs limites et à un sentiment d’impuissance. Nous avons cherché à comprendre à travers cette recherche, tant ce qui rend le suivi de ces situations délicat et complexe, que ce qui guide les professionnels tout au long de ces suivis. Pour répondre à cette question, nous avons fait le choix d’interroger des intervenants en protection de l’enfance, mais aussi des conseillers sociaux et un professionnel de Point jeunes. Nous avons utilisé comme méthode « l’entretien compréhensif » de Jean-Claude Kaufmann, car nous voulions mettre en avant la parole des intervenants et le savoir de terrain. Ce travail met en évidence les processus complexes qui produisent du « décrochage » et montre comment les intervenants interagissent pour donner sens et cohérence aux politiques promues. Un élément central qui apparaît est la nécessité de mettre en place une coordination dans les actions menées, afin que la souffrance engendrée par ces processus ne soit pas occultée

Der 'historische Block' des 'Modells Deutschland'

PROKLA: Die PROKLA wird dieses Jahr zehn Jahre alt; um diesen Geburtstag zu begehen, haben wir uns überlegt, daß es für Marxisten immer das Wichtigste ist, eine konkrete Analyse der gegenwärtigen Situation zu leisten. In unserem nächsten Heft wollen wir daher einige ausländische Genossen zu Wort kommen lassen, um ihre Analyse der gegenwärtigen Situation des 'Modells Deutschland' in die Diskussion einzubringen. Du arbeitest ja seit langem darüber und bist jetzt dabei, ein Schwerpunktheft von »Politique Aujourd'hui« zu dem Thema vorzubereiten - wie siehst Du die gegenwärtige Entwicklung dieser Bundesrepublik? Und wie erklärst Du das eigentlich, daß gerade in der französischen Diskussion immer wieder von der Repression, der Modernisierung der Polizei in der BRD die Rede ist - nicht aber von der 'Modernisierung der Volkswirtschaft' und der 'konzentrierten Aktion', der Einbindung der Branchengewerkschaften in die kapitalistische Konkurrenz und in die 'selektive Wirtschaftspolitik' des Staates?A.A.: Um das zu beantworten, muß ich weit ausholen ... Zunächst: Irrtümer sind nicht immer interessant und ernstzunehmen, nur bestimmte Irrtümer verdienen das! Zu den uninteressanten Irrtümern gehört das paranoide Bild von Deutschland als einem Polizeistaat, als einem faschistischen Staat usf. Zumindest ein Teil dieses Irrtums verdient wirklich keinerlei Beachtung: Das ist einfach der französische Chauvinismus, der sich hier austobt - auch in der Presse der PCF und in der gesamten linken Presse! Aber es gibt da auch noch einen interessanten Irrtum, den wir diskutieren müssen: Die französische Intelligentsia - von der dieses Deutschlandbild verbreitet wird - ist immer noch wie traumatisiert durch das Verschwinden jeden Begriffs von Deutschland, wie er in französischen Köpfen existierte, nach 1945, aufgrund der deutschen Teilung, der Vernichtung des Dritten Reiches

Modelling ground pickup for microwave telescopes

Microwave telescopes require an ever-increasing control of experimental systematics in their quest to measure the Cosmic Microwave Background (CMB) to exquisite levels of precision. One important systematic for ground and balloon-borne experiments is ground pickup, where beam sidelobes detect the thermal emission of the much warmer ground while the main beam is scanning the sky. This generates scan-synchronous noise in experiment timestreams, which is difficult to filter out without also deleting some of the signal from the sky. Therefore, efficient modelling of pickup can help guide the design of experiments and of analysis pipelines. In this work, we present an extension to the beamconv algorithm that enables us to generate time-ordered data (TOD) from beam-convolved sky and ground maps simultaneously. We simulate ground pickup for both a ground-based experiment and a telescope attached to a stratospheric balloon. Ground templates for the balloon experiment are obtained by re-projecting satellite maps of the Earth's microwave emission.Comment: 10 pages, 6 figures, paper 12190-165 for the "SPIE AT+I 2022 mm, sub-mmm, and Far-Infrared Detectors and Instrumentation for Astronomy XI" conferenc

Electron Mass Operator in a Strong Magnetic Field and Dynamical Chiral Symmetry Breaking

The electron mass operator in a strong magnetic field is calculated. The contribution of higher Landau levels of virtual electrons, along with the ground Landau level, is shown to be essential in the leading log approximation. The effect of the electron dynamical mass generation by a magnetic field is investigated. In a model with N charged fermions, it is shown that some critical number N_{cr} exists for any value of the electromagnetic coupling constant alpha, such that the fermion dynamical mass is generated with a doublet splitting for N < N_{cr}, and the dynamical mass does not arise at all for N > N_{cr}, thus leaving the chiral symmetry unbroken.Comment: 4 pages, REVTEX4, 3 figure

Árvores binominais implícitas: aplicação para as opções de Telebrás no exercício de abril de 1999

Unavailable.Este trabalho utiliza o método de árvores binomiais implícitas proposto por Rubinstein (1994), comparando-o com o modelo de Black-Scholes (1973) na construção e manutenção de um portfólio de hedge. O método de árvores binomiais implícitas tenta encontrar uma única árvore binomial que descreva o comportamento do ativo-objeto, de forma que todos os prêmios de opções calculados a partir desta árvore estejam em consonância com os valores observados no mercado para todos os diferentes preços de exercício. Obtêm-se os parâmetros utilizados para hedge da árvore binomial implícita calculada e constroem-se os portfólios, comparando a sua eficácia de hedge com os portfólios que utilizam os parâmetros fornecidos pelo modelo de Black-Scholes. A amostra utilizada constituiu-se dos prêmios de opções dos recibos de Telebrás no período de 2 de março a 16 de abril de 1999. Os resultados indicam que não foram encontradas diferenças estatisticamente significativas entre os portfólios construídos e ajustados pelo modelo aqui apresentado com os portfólios que empregaram os parâmetros de hedge dados pelo modelo de Black-Scholes

Microscopic Calculation of the Constitutive Relations

Homogenization theory is used to calculate the macroscopic dielectric constant from the quantum microscopic dielectric function in a periodic medium. The method can be used to calculate any macroscopic constitutive relation, but it is illustrated here for the case of electrodynamics of matter. The so-called cell problem of homogenization theory is solved and an explicit expression is given for the macroscopic dielectric constant in a form akin to the Clausius-Mossotti or Lorentz-Lorenz relation. The validity of this expression is checked by showing that the macroscopic dielectric constant is causal and has the expected symmetry properties, and that the average of the microscopic energy density is the macroscopic one. Finally, the general expression is applied to Bloch eigenstates. Finally, the corresponding many-body problem is briefly discussed.Comment: 14 pages, 2 figure

A Minimal Model of Metabolism Based Chemotaxis

Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominantly studied as metabolism-independent. All available simulation models of bacterial chemotaxis endorse this assumption. Recent studies have shown, however, that many metabolism-dependent chemotactic patterns occur in bacteria. We hereby present the simplest artificial protocell model capable of performing metabolism-based chemotaxis. The model serves as a proof of concept to show how even the simplest metabolism can sustain chemotactic patterns of varying sophistication. It also reproduces a set of phenomena that have recently attracted attention on bacterial chemotaxis and provides insights about alternative mechanisms that could instantiate them. We conclude that relaxing the metabolism-independent assumption provides important theoretical advances, forces us to rethink some established pre-conceptions and may help us better understand unexplored and poorly understood aspects of bacterial chemotaxis

Casimir effect: running Newton constant or cosmological term

We argue that the instability of Euclidean Einstein gravity is an indication that the vacuum is non perturbative and contains a condensate of the metric tensor in a manner reminiscent of Yang-Mills theories. As a simple step toward the characterization of such a vacuum the value of the one-loop effective action is computed for Euclidean de Sitter spaces as a function of the curvature when the unstable conformal modes are held fixed. Two phases are found, one where the curvature is large and gravitons should be confined and another one which appears to be weakly coupled and tends to be flat. The induced cosmological constant is positive or negative in the strongly or weakly curved phase, respectively. The relevance of the Casimir effect in understanding the UV sensitivity of gravity is pointed out.Comment: Final, slightly extended version, to appear in Classical and Quantum Gravit

Learning from Complex Systems: On the Roles of Entropy and Fisher Information in Pairwise Isotropic Gaussian Markov Random Fields

Markov Random Field models are powerful tools for the study of complex systems. However, little is known about how the interactions between the elements of such systems are encoded, especially from an information-theoretic perspective. In this paper, our goal is to enlight the connection between Fisher information, Shannon entropy, information geometry and the behavior of complex systems modeled by isotropic pairwise Gaussian Markov random fields. We propose analytical expressions to compute local and global versions of these measures using Besag's pseudo-likelihood function, characterizing the system's behavior through its \emph{Fisher curve}, a parametric trajectory accross the information space that provides a geometric representation for the study of complex systems. Computational experiments show how the proposed tools can be useful in extrating relevant information from complex patterns. The obtained results quantify and support our main conclusion, which is: in terms of information, moving towards higher entropy states (A --> B) is different from moving towards lower entropy states (B --> A), since the \emph{Fisher curves} are not the same given a natural orientation (the direction of time).Comment: 46 pages, 16 Figure

J/psi production in Au-Au collisions at root s(NN)=200 GeV

First results on charm quarkonia production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The yield of J/psi\u27s measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au-Au reactions at roots(NN) = 200 GeV is analyzed as a function of collision centrality. For this analysis we have studied 49.3x10(6) minimum bias Au-Au reactions. We present the J/psi invariant yield dN/dy for peripheral and midcentral reactions. For the most central collisions where we observe no signal above background, we quote 90% confidence level upper limits. We compare these results with our J/psi measurement from proton-proton reactions at the same energy. We find that our measurements are not consistent with models that predict strong enhancement relative to binary collision scaling