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Mazali T.,University Telematica Internazionale Uninettuno
Leonardo | Year: 2011

The information and communication technology system is constantly creating new scenarios, but a tendency in them can still be recognized: the blurring of the limits between consumers and producers and the passage from interactivity to participation (user generated contents, web 2.0, social networks). In this emerging cultural context, constantly redefined and remediated by individual and personalized forms of elaboration, it is important to understand the way in which every single person or group leads his/her own way towards reappropriation of the technological realm. The author aims to explore potential and real capacities of these new technologies to generate a new public sphere by analyzing an exemplary case study: the moblog communities in the megaphone.net project. © 2011 ISAST.

Ruggiero M.L.,University Telematica Internazionale Uninettuno | Ruggiero M.L.,Polytechnic University of Turin | Iorio L.,National Institute of Nuclear Physics, Italy
General Relativity and Gravitation | Year: 2010

We study the effects of a time-varying gravitomagnetic field on the motion of test particles. Starting from recent results, we consider the gravitomagnetic field of a source whose spin angular momentum has a linearly time-varying magnitude. The acceleration due to such a time-varying gravitomagnetic field is considered as a perturbation of the Newtonian motion, and we explicitly evaluate the effects of this perturbation on the Keplerian elements of a closed orbit. The theoretical predictions are compared with actual astronomical and astrophysical scenarios, both in the solar system and in binary pulsars systems, in order to evaluate the impact of these effects on real systems. © 2010 Springer Science+Business Media, LLC.

Iorio L.,R.A.U.M. | Ruggiero M.L.,University Telematica Internazionale Uninettuno | Ruggiero M.L.,Polytechnic University of Turin
International Journal of Modern Physics A | Year: 2010

We focus on HořavaLifshitz (HL) theory of gravity, and, in particular, on the Kehagias and Sfetsos's solution that is the analog of Schwarzschild black hole of General Relativity. In the weak-field and slow-motion approximation, we analytically work out the secular precession of the longitude of the pericentre ̄ω of a test particle induced by this solution. Its analytical form is different from that of the general relativistic Einstein's pericentre precession. Then, we compare it to the latest determinations of the corrections Δ ̄ω̇ to the standard Newtonian/Einsteinian planetary perihelion precessions recently estimated by E. V. Pitjeva with the EPM2008 ephemerides. It turns out that the planets of the solar system, taken singularly one at a time, allow one to put lower bounds on the adimensional HL parameter ψ0 of the order of 10-12 (Mercury)-10-24 (Pluto). They are not able to account for the Pioneer anomalous acceleration for r > 20 AU. © 2010 World Scientific Publishing Company.

Assante D.,University Telematica Internazionale Uninettuno | Verolino L.,University of Naples Federico II
Progress In Electromagnetics Research M | Year: 2012

We discuss the electromagnetic interaction between a traveling charge particle and a perfectly conducting strip of a negligible thickness. The particle travels at a constant velocity along a straight line parallel to the axis of symmetry of the strip. The efficiency of the proposed solution is proved by evaluating the longitudinal coupling impedance in a wide range of parameters.

Cacciapuoti C.,Institute For Angewandte Mathematik | Cacciapuoti C.,University of Insubria | Finco D.,University Telematica Internazionale Uninettuno | Noja D.,University of Milan Bicocca | Teta A.,University of Rome La Sapienza
Letters in Mathematical Physics | Year: 2014

In the present paper, we study the following scaled nonlinear Schrödinger equation (NLS) in one space dimension:(Formula Presented.)(Formula Presented.) This equation represents a nonlinear Schrödinger equation with a spatially concentrated nonlinearity. We show that in the limit (Formula Presented.) the weak (integral) dynamics converges in (Formula Presented.) to the weak dynamics of the NLS with point-concentrated nonlinearity: (Formula Presented.) where Hα is the Laplacian with the nonlinear boundary condition at the origin (Formula Presented.) and (Formula Presented.). The convergence occurs for every (Formula Presented.) if V ≥  0 and for every (Formula Presented.) otherwise. The same result holds true for a nonlinearity with an arbitrary number N of concentration points. © 2014, Springer Science+Business Media Dordrecht.

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