6,394 research outputs found
Premessa dei curatori
No full textPremessa introduttiva al volume che raccoglie gli scritti in memoria del giurista modenese Gladio Gemm
L’ART. 11 COME “DIRETTIVA FEDERALISTICA” DELLA COSTITUZIONE. ATTUALITÀ DI UNA RIFLESSIONE
No full textModified special relativity on a fluctuating spacetime
No full textIt was recently proposed that deformations of the relativistic symmetry, as those considered in deformed
special relativity (DSR), can be seen as the outcome of a measurement theory in the presence of nonnegligible
(albeit small) quantum gravitational fluctuations [S. Liberati, S. Sonego, and M. Visser, Phys.
Rev. D 71, 045001 (2005).][R. Aloisio, A. Galante, A. Grillo, S. Liberati, E. Luzio, and F. Mendez, Phys.
Rev. D 73, 045020 (2006).]. In this paper we explicitly consider the case of a spacetime described by a flat
metric endowed with stochastic fluctuations and, for a free particle, we show that DSR-like nonlinear
relations between the spaces of the measured and classical momenta, can result from the average of the
stochastic fluctuations over a scale set to be the de Broglie wavelength of the particle. As illustrative
examples we consider explicitly the averaging procedure for some simple stochastic processes and discuss
the physical implications of our results
Modified Special Relativity on a fluctuating spacetime
No full textIt was recently proposed that deformations of the relativistic symmetry, as those considered in deformed special relativity (DSR), can be seen as the outcome of a measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations [S. Liberati, S. Sonego, and M. Visser, Phys. Rev. D 71, 045001 (2005).][R. Aloisio, A. Galante, A. Grillo, S. Liberati, E. Luzio, and F. Mendez, Phys. Rev. D 73, 045020 (2006).]. In this paper we explicitly consider the case of a spacetime described by a flat metric endowed with stochastic fluctuations and, for a free particle, we show that DSR-like nonlinear relations between the spaces of the measured and classical momenta, can result from the average of the stochastic fluctuations over a scale set to be the de Broglie wavelength of the particle. As illustrative examples we consider explicitly the averaging procedure for some simple stochastic processes and discuss the physical implications of our results
Super Heavy Dark Matter in light of BICEP2, Planck and Ultra High Energy Cosmic Rays Observations
No full textThe announcement by BICEP2 of the detection of B-mode polarization consistent with primordial gravitational waves with a tensor-to-scalar ratio, r=0.2+0.07-0.05, challenged predictions from most inflationary models of a lower value for r. More recent results by Planck on polarized dust emission show that the observed tensor modes signal is compatible with pure foreground emission. A more significant constraint on r was then obtained by a joint analysis of Planck, BICEP2 and Keck Array data showing an upper limit to the tensor to scalar ratio r≤ 0.12, excluding the case 0r= with low statistical significance. Forthcoming measurements by BICEP3, the Keck Array, and other CMB polarization experiments, open the possibility for making the fundamental measurement of r. Here we discuss how r sets the scale for models where the dark matter is created at the inflationary epoch, the generically called super-heavy dark matter models. We also consider the constraints on such scenarios given by recent data from ultrahigh energy cosmic ray observatories which set the limit on super-heavy dark matter particles lifetime. We discuss how super-heavy dark matter can be discovered by a precise measurement of r combined with future observations of ultra high energy cosmic rays
The Maltese Workshop of the Gili. From the Commissions for the Knights of Ursulo to the Malta Map of Aloisio
No full textThe analysis of the Gili workshop in Valletta between the end of the sixteenth century and the first half of the seventeenth century is the starting point to investigate the figure of Aloisio,an eclectic and versatile personality working as a goldsmith, cartographer and besides, and his map of Malta (1614
SU REFERENDUM E DEMOCRAZIA: RIPRENDENDO UN DIALOGO (TROPPO PRESTO) INTERROTTO CON GLADIO GEMMA
No full textScritto in memoria del costituzionalista modenese Gladio Gemma (1938-2021) in cui si delinea la personalità scientifica ed umana dell’Autore attraverso una disanima dei Suoi numerosi scritti in tema di ammissibilità delle richieste di referendum abrogativ
Probabilistic Comparative Analysis of Vehicle-Bridge Interaction Models for Predicting Bridge Response under Moving Vehicles
No full textThis paper compares three approaches for predicting the bridge response under moving vehicles. The first approach represents the vehicle as a concentrated moving load, while the second and third approaches simulate the vehicle using single (1-dof) and two (2-dof) degrees of freedom models, respectively. The vehicle-bridge models have been implemented following a finite-difference formulation. These models have been validated against the experimental displacement response of a mid-span prestressed reinforced concrete bridge. Parametric analyses have been conducted to investigate the impact of road roughness on the discrepancies between the models' predictions. An increasing level of road roughness, modeled according to ISO-8608, tends to conceal the mutual differences between the models' outcomes. Furthermore, a Monte Carlo simulation has been employed to fit the probability distributions of two indicators, comparing the bridge displacement responses in three roughness scenarios and considering variable velocity and vehicle characteristics. The primary objective is to assess whether there are scenarios where vehicle-bridge interaction modeling becomes indispensable for accurately estimating the vehicle's effect on the bridge response. The paper presents expressions for four probability density functions of the chosen metric, facilitating the comparison between the 1-dof and 2-dof models with the concentrated load approach
Ultra High Energy Cosmic Rays: Anisotropies and spectrum
No full textThe recent results of the Pierre Auger Observatory on the possible correlation of Ultra High Energy Cosmic Rays events and several nearby discrete sources could be the starting point of a new era with charged particles astronomy. In this paper we introduce a simple model to determine the effects of any local distribution of sources on the expected flux. We consider two populations of sources: faraway sources uniformly distributed and local point sources. We study the effects on the expected flux of the local distribution of sources, referring also to the set of astrophysical objects whose correlation with the Auger events is experimentally claimed. © 2011 Elsevier B.V. All rights reserved
Protocol-independent, fixed-latency links with FPGA-embedded SerDeses
No full textMost high-speed Serializer-Deserializer (SerDes) chips have a random latency through the data-path each time the link is established (e.g. after a reset, a loss of signal or a power cycle). However, there are fields of applications, such as timing synchronization, radio equipment control and trigger systems of High Energy Physics experiments that would benefit from fixed-latency links. In this paper, we present a link architecture based on high-speed SerDeses circuits embedded in Field Programmable Gate Array (FPGAs). Our architecture works with fixed-latency, it is independent of the protocol and can be customized to support any. As an example of implementation, we report on a synchronous 2.5-Gbps 8B10B serial link. © 2012 IOP Publishing Ltd and Sissa Medialab srl
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