Spacetime metric from linear electrodynamics

The Maxwell equations are formulated on an arbitrary (1+3)-dimensional manifold. Then, imposing a (constrained) linear constitutive relation between electromagnetic field $(E,B)$ and excitation $({\cal D},{\cal H})$, we derive the metric of spacetime therefrom.Comment: 4 pages' latex-scrip

About Superluminal motions and Special Relativity: A Discussion of some recent Experiments, and the solution of the Causal Paradoxes

Some experiments, performed at Berkeley, Cologne, Florence, Vienna, Orsay, Rennes, etc., led to the claim that something seems to travel with a group velocity larger than the speed c of light in vacuum. Various other experimental results seem to point in the same direction: For instance, localized wavelet- type solutions to Maxwell equations have been found, both theoretically and experimentally, that travel with superluminal speed. [Even muonic and electronic neutrinos [it has been proposed] might be "tachyons", since their square mass appears to be negative]. With regard to the first-mentioned experiments, it was recently claimed by Guenter Nimtz that those results with evanescent waves (or tunneling photons) imply superluminal signal and impulse transmission, and therefore violate Einstein causality. In this note we want to stress that, on the contrary, all such results do not place relativistic causality in jeopardy, even if they referred to actual tachyonic motions: In fact, Special Relativity can cope even with superluminal objects and waves. For instance, it is possible (at least in microphysics) to solve also the known causal paradoxes, devised for faster than light motion, although this is not widely recognized yet. Here we show, in detail and rigorously, how to solve the oldest causal paradox, originally proposed by Tolman, which is the kernel of many further tachyon paradoxes (like J.Bell's, F.A.E.Pirani's, J.D.Edmonds' and others'). The key to the solution is a careful application of tachyon mechanics, as it unambiguously follows from special relativity. At Last, in one of the two Appendices, we propose how to evaluate the group-velocity in the case of evanescent waves. [PACS nos.: 03.30.+p; 03.50.De; 41.20.Jb; 73.40.Gk; 84.40.Az; 42.82.Et ]Comment: LaTeX file: 26 pages, with 5 Figures (and two Appendices). The original version of this paper appeared in the Journal below

Dispositivos móveis na escola : redefinição de ambientes e métodos de aprendizagem no contexto italiano

Recenti studi hanno messo in evidenza l'importanza dell'analisi dei bisogni nella progettazione delle classi digitali. Questo articolo propone una riflessione sulla realizzazione di ambienti didattici innovativi in relazione agli impianti didattici che tengono conto dell\u2019incremento della diffusione dei device mobile nella scuola italiana. Recentemente l'attenzione sulle didattiche attive e sugli apprendimenti informali integrati all\u2019uso dei device mobile ha avuto particolare riscontro nelle correnti della Flipped lesson e degli Episodi di Apprendimento Situato, EAS, che si stanno posizionando come alcuni dei metodi pi\uf9 interessanti per sostenere il rinnovamento delle pratiche scolastiche. Questi metodi sono basati sul lavoro di gruppo sia in aula che a casa con i dispositivi digitali e sul modello BYOD Bring Your Own Device (porta il tuo device a scuola). La scelta del metodo di insegnamento \ue8 perci\uf2 fondamentale in una societ\ue0 in cui l'uso di internet \ue8 in crescita e la possibilit\ue0 di essere sempre pi\uf9 collegati durante l\u2019intera giornata permettono processi di Pervasive LearningThis article discusses some recent studies that allow us to understand the importance of analyzing the educational needs in the conceiving of the digital classroom and its possible redefinitions in the learning and methods environment. This paper also proposes a reflection on the implementation of innovative educational environments and settings through mobile technologies in Italian schools. Recently, the focus on active teaching and informal learning with the integration of mobile devices has reflected in the current Flipped Lesson and in the Episodes of Situated Learning EAL, some of the most interesting methods to support the renovation of school practice. These methods are based on group work both in the classroom and at home with digital devices and BYOD Bring Your Own Device model. Choosing the right teaching method to the current challenges is fundamental in a society where the use of the internet increases every day and the possibility of being always connected provides diffuse learning processe

An Experimental and Numerical Study on Glass Frit Wafer-to-Wafer Bonding

A thermo-mechanical wafer-to-wafer bonding process is studied through experiments on the glass frit material and thermo-mechanical numerical simulations to evaluate the effect of the residual stresses on the wafer warpage. To experimentally characterize the material, confocal laser profilometry and scanning electron microscopy for surface observation, energy dispersive X-ray spectroscopy for microstructural investigation, and nanoindentation and die shear tests for the evaluation of mechanical properties are used. An average effective Young’s modulus of 86.5 ± 9.5 GPa, a Poisson’s ratio of 0.19 ± 0.02, and a hardness of 5.26 ± 0.8 GPa were measured through nanoindentation for the glass frit material. The lowest nominal shear strength ranged 1.13 ÷ 1.58 MPa in the strain rate interval to 0.33 ÷ 4.99 × 10 (Formula presented.) s (Formula presented.). To validate the thermo-mechanical model, numerical results are compared with experimental measurements of the out-of-plane displacements at the wafer surface (i.e., warpage), showing acceptable agreement

The dramaturgy of music: its impact on my composition

This submission for PhD by Prior Output (comprising of six compositions and this dissertation) defines my personal approach to musical composition using music dramaturgy as its main source of inspiration and expression, contextualising the compositions within other pieces in the field and also within my own production. The pieces were selected following recommendations and regulations from the Graduate School at London Metropolitan University, which are fully explained in section II.L A further criterion for the selection of precisely these six pieces was, that in spite of their apparent diversity (showing a vast range of compositional techniques, including acousmatic music, ensemble and solo pieces with live-electronics) they nevertheless form a 'coherent whole', as it is explained in section ILi and ll.ii. A detailed analysis of the compositional techniques for each of the six works, a list of all works and publications of my authorship in the public domain, reviews about some of the works and diverse publications related to the compositions or main subjects are presented in the Appendices, as required. Papers which are relevant either to the pieces or to some of the concepts explained in this dissertation are presented in the appendices XV to XIX. List of the works included in the prior output: Geqenstitze (gegenseitig): alto flute, quadraphonic tape and live-electronics (ca. 33') Arte Poetice (I): quadrophonic tape (ca. 8') Overture (in memoriam T.A. T.): quadrophonic tape (ca. 11') Spectral colours: ensemble and tape (ca. 11') Color Code: quadrophonic tape and live-electronics, live viola, video (ca. 30') L.S. (waiting for changes): small orchestra (ca.12') Keywords Music dramaturgy, intrinsic and extrinsic music dramaturgy, communication process, musical discourse, musical semiotics, sound imprint, intention/reception, something-to-hold-on-to-factors

Espectrómetro de doble paso, simple y económico, para analizar radiación láser

En distintas épocas, antes y después del advenimiento del láser, se han diseñado espectrómetros ópticos para incrementar la dispersión con la cual se desea analizar la radiación o bien para reducir lo más posible la luz difundida en los elementos dispersivos, prismas o redes de difracción. Una vez que el láser pasó a ser una eficaz herramienta de laboratorio, varios campos de la óptica encontraron la oportunidad de lograr desarrollos sensacionales. La holografía y la espectroscopia de la radiación dispersada por la materia, constituyen ejemplos notables de aquellos campos de la óptica en los que el láser provocó una situación de avance sin precedentes. En el caso de los estudios de la radiación dispersada por la materia, fue necesario el diseño de espectrómetros especiales para detectar, por ejemplo, las débiles señales Stokes y anti-Stokes, excitadas por láseres diversos, en gases, líquidos o sol idos. Los espectrómetros ópticos o monocromadores usados en la investigación del efecto Raman, pueden clasificarse en tres tipos: a) los monocromadores de doble paso; b) los monocromadores duales y c) los monocromadores en tándem

Innovazione dei setting per la didattica universitaria

In recent years, Italian universities have been called upon to experiment with innovative processes and changes that have involved different aspects. This contribution focuses in particular on the factors related to teaching that influence the design of university settings, characterized by student\u2019s profile evolution, the pervasiveness of the media and the ever-increasing demand to develop skills. and achieve the stated training goals are some aspects that have influenced the teaching. BYOD, inverted classroom, feedback, experience learning are considered relevant factors for the re-definition of settings for university teaching Starting from two approaches, teacher or student-centered, some scenarios that could characterize in the next decades the following university settings: the lecture hall, the small classroom in presence, the online synchronous environments and the asynchronous online environments

bullous wells syndrome associated with non hodgkin s lymphocytic lymphoma

3/µl; eosinophils 14.3% neutrophils 48%, lymphocytes 31.2%, monocytes 6.5%, basophils 0.2%), total immunoglobulin E (IgE) = 751 IU/ml, C-reactive protein (CRP) 1.25 mg/dl, erythrocyte sedimentation rate (ESR) in the first hour 60 mm; viral markers (Epstein Barr virus, cytomegalovirus, hepatitis A, B and C virus), cryoglobulin, ANCA, LAC, ANA, ENA and anti-DNA antibodies were all negative. Histopathological examination of the lesion on the left leg showed an epidermis characterized by multiple, sometimes confluent vesicles containing serum and eosinophil granulocytes. The underlying papillary dermis was markedly oedematous, with focal and minimal erythrocytic extravasations and an interstitial eosinophil granulocytic infiltrate. The reticular dermis was infiltrated by a large number of prevalently perivascular lymphocytic elements and numerous perivascular and interstitial eosinophil granulocytes, which also extended along the interlobular hypodermal septa and, to a lesser extent, the hypodermic lobules. The reticular dermis also showed some small and isolated flame figures (Fig. 2). The diagnosis of Wells' syndrome was made on the basis of the clinical picture and the histological findings, together with a negative direct immunofluorescence test (5). Having excluded pharmacological, infective, vasculitic and inflammatory causes, the subsequent instrumental and laboratory investigations were aimed at identifying a possible relapse of the patient's previous neoplastic disease. Complete abdominal ultrasonography, chest radiography and colonoscopy were negative, as was a search for tumour markers. The physical examination findings of numerous swollen inguinal and axillary lymph nodes therefore drew our attention to a possible underlying lymphoproliferative disease, and a subsequent lymph node biopsy revealed a picture compatible with a diffuse, small-cell non-Hodgkin's B lymphoma/ B-cell CLL, which was confirmed by a bone marrow biopsy