601 research outputs found

    The Casimir effect from the point of view of algebraic quantum field theory

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    We consider a region of Minkowski spacetime bounded either by one or by two parallel, infinitely extended plates orthogonal to a spatial direction and a real Klein-Gordon field satisfying Dirichlet boundary conditions. We quantize these two systems within the algebraic approach to quantum field theory using the so-called functional formalism. As a first step we construct a suitable unital *-algebra of observables whose generating functionals are characterized by a labelling space which is at the same time optimal and separating and fulfils the F-locality property. Subsequently we give a definition for these systems of Hadamard states and we investigate explicit examples. In the case of a single plate, it turns out that one can build algebraic states via a pull-back of those on the whole Minkowski spacetime, moreover inheriting from them the Hadamard property. When we consider instead two plates, algebraic states can be put in correspondence with those on flat spacetime via the so-called method of images, which we translate to the algebraic setting. For a massless scalar field we show that this procedure works perfectly for a large class of quasi-free states including the Poincar\'e vacuum and KMS states. Eventually Wick polynomials are introduced. Contrary to the Minkowski case, the extended algebras, built in globally hyperbolic subregions can be collected in a global counterpart only after a suitable deformation which is expressed locally in terms of a *-isomorphism. As a last step, we construct explicitly the two-point function and the regularized energy density, showing, moreover, that the outcome is consistent with the standard results of the Casimir effect.Comment: 45 pages, section 2 improved, typos correcte

    Creativity at the crossroad. Creative education as moral education?

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    IP-Lab 6: Cambiamento e CreativitĂ 

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    La formazione del questioning approach: dispositivo metodologico e piano valutativo

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    Le professioni coinvolte nella relazione educativa richiedono competenze specifiche per affrontare le situazioni che, per la presenza “umana”, non possono e non devono essere anticipate da formule o procedure. Tali competenze non sono sempre questione di conoscenze o di strumenti. In alcuni casi, rimandano ad approcci: è questo il caso della competenza della problematizzazione, competenza necessaria per leggere e interpretare nel modo più fedele possibile i significati aperti dalla situazione. Come le altre competenze, anche quella di un approccio problematizzante (questioning approach) richiede una formazione, una formazione particolarmente urgente nelle professioni di cura, dove la relazione con l’altro si misura con la “sospensione” della malattia. Il contributo argomenta a favore della necessità di uno specifico percorso di formazione dell’approccio problematizzante e propone una metodologia di intervento - le 3RPlay - caratterizzata dal dispositivo del pretesto e dal relativo piano valutativo.Le professioni coinvolte nella relazione educativa richiedono competenze specifiche per affrontare le situazioni che, per la presenza “umana”, non possono e non devono essere anticipate da formule o procedure. Tali competenze non sono sempre questione di conoscenze o di strumenti. In alcuni casi, rimandano ad approcci: è questo il caso della competenza della problematizzazione, competenza necessaria per leggere e interpretare nel modo più fedele possibile i significati aperti dalla situazione. Come le altre competenze, anche quella di un approccio problematizzante (questioning approach) richiede una formazione, una formazione particolarmente urgente nelle professioni di cura, dove la relazione con l’altro si misura con la “sospensione” della malattia. Il contributo argomenta a favore della necessità di uno specifico percorso di formazione dell’approccio problematizzante e propone una metodologia di intervento - le 3RPlay - caratterizzata dal dispositivo del pretesto e dal relativo piano valutativo

    Automatic classification of autism spectrum disorder in children using cortical thickness and support vector machine

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    Objective: Autism spectrum disorder (ASD) is a neurodevelopmental condition with a heterogeneous phenotype. The role of biomarkers in ASD diagnosis has been highlighted; cortical thickness has proved to be involved in the etiopathogenesis of ASD core symptoms. We apply support vector machine, a supervised machine learning method, in order to identify specific cortical thickness alterations in ASD subjects. Methods: A sample of 76 subjects (9.5 \ub1 3.4 years old) has been selected, 40 diagnosed with ASD and 36 typically developed subjects. All children underwent a magnetic resonance imaging (MRI) examination; T1-MPRAGE sequences were analyzed to extract features for the characterization and parcellation of regions of interests (ROI); average cortical thickness (CT) has been measured for each ROI. For the classification process, the extracted features were used as input for a classifier to identify ASD subjects through a "learning by example" procedure; the features with best performance was then selected by "greedy forward-feature selection." Finally, this model underwent a leave-one-out cross-validation approach. Results: From the training set of 68 ROIs, five ROIs reached accuracies of over 70%. After this phase, we used a recursive feature selection process in order to identify the eight features with the best accuracy (84.2%). CT resulted higher in ASD compared to controls in all the ROIs identified at the end of the process. Conclusion: We found increased CT in various brain regions in ASD subjects, confirming their role in the pathogenesis of this condition. Considering the brain development curve during ages, these changes in CT may normalize during development. Further validation on a larger sample is required

    Sosialisasi Dan Konseling Penyakit Hipertensi Beserta Komplikasinya Di Desa Jayaraharja, Sukajaya, Bogor

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    Hipertensi merupakan salah satu penyakit kardiovaskular yang paling umum dan paling banyak diderita masyarakat. Hipertensi sering disebut juga sebagai silent killer karena gejalanya sering tanpa ada keluhan. Biasanya, penderita tidak menyadari kalau dirinya mengidap hipertensi dan baru diketahui setelah terjadi komplikasi. Tujuan kegiatan pengabdian masyarakat ini adalah pemberian sosialisasi dan layanan konsultasi dalam pencegahan dan pengendalian hipertensi diantaranya dengan cara meningkatkan promosi kesehatan melalui Gerakan Masyarakat Hidup Sehat (Germas) dengan perilaku CERDIK (Cek kesehatan secara berkala, Enyahkan asap rokok, Rajin aktifitas fisik, Diet sehat dan seimbang, Istirahat yang cukup, dan Kelola stres). Metode yang digunakan oleh tim pengabdian meliputi sosialisasi, pemeriksaan kesehatan, konseling dan pengisian angket. Seluruh kegiatan ini dibantu oleh mahasiswa dan perangkat desa. Hasil yang dicapai pada pelaksanaan pengabdian masyarakat ini adalah memberikan dampak positif terhadap masyarakat, yaitu pengetahuan tentang kesadaran terhadap penyakit Hipertensi, masyarakat antusias menerima sosialisasi dan pemeriksaan kesehatan yang terlihat berdasarkan data 89% peserta meyatakan sangat tertarik dan antusias dengan kegiatan ini
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