171,293 research outputs found
Italia Epigrafica Digitale, XV (Dicembre 2017), Sardinia, schede nn. 6; 9-14; 27-32; 38-39; 42-44; 67-69; 110; 125-129; 131-132; 135-136; 312-313; 315-316; 320; 324; 326; 807; 899; 900-903; 911; 915; 972-976; 989; 1017; 1030-1031; 1105-1107; 1168-1172; 1174-1186; 1190-1191; 1195
No full textIl volume, con una breve introduzione di Antonio M. Corda, raccoglie 1378 schede relative alle iscrizioni latine della Sardinia, fotografando la situazione della banca dati elettronica EDR al 3 maggio 2016 e senza tener conto delle successive integrazioni, correzioni e già disponibili in rete.
Le schede sono un'edizione critica, cartacea, di una schedatura digitale iniziata nel 2002, progressivamente emendata o aggiornata sino al 201
On the quantization of the extremal Reissner-Nordström black hole
No full textFollowing Rosen's quantization rules, two of the authors (C. Corda and F. Feleppa) recently described the Schwarzschild black hole (BH) formed after the gravitational collapse of a pressureless “star of dust” in terms of a “gravitational hydrogen atom”. Here we generalize this approach to the gravitational collapse of a charged object, namely, to the geometry of a Reissner-Nordström BH (RNBH) and calculate the gravitational potential, the Schrödinger equation and the exact solutions of the energy levels of the gravitational collapse. By using the concept of BH effective state, previously introduced by one of us (CC), we describe the quantum gravitational potential, the mass spectrum and the energy spectrum for the extremal RNBH. The area spectrum derived from the mass spectrum finds agreement with a previous result by Bekenstein. The stability of these solutions, described with the Majorana approach to the Archaic Universe scenario, shows the existence of oscillatory regimes or exponential damping for the evolution of a small perturbation from a stable state
Hologram Domain Data Compression: Performance of Standard Codecs and Image Quality Assessment at Different Distances and Perspectives
No full textComputer generated holograms represent a novel digital media that with adequate processing tools and the advance of holographic display technologies will foster the development of true immersive video technologies applications. A digital hologram typically conveys a considerable amount of data making compression and image quality evaluation tools necessary for the development of practical applications. This paper proposes an objective evaluation of the performances of state-of-the-art compression techniques applied to digital holographic data. The experimental analysis takes into account several holographic images reconstructing the holograms from different perspectives and distances. The results of the exploratory study are reported, discussed and complemented with a statistical analysis of the hologram data under test, providing insights for computer-generated holography compression techniques design
Rhodalgal-foramol facies in equatorial carbonates. Insights from Miocene tectonic islands of the central Atlantic
No full textShallow-water carbonates ranging in thickness from 250 to 500 m have been deposited during the Miocene on
the summit of transverse ridges flanking the Romanche and Vema transforms that offset the equatorial Mid-
Atlantic Ridge. These carbonate platforms are dominated by the same biota assemblages consisting mainly of
perforate larger benthic foraminifera and red algae; corals are present occasionally as minor components.
We discuss several factors (i.e. temperature of sea water, elevated CO2 levels, hydrothermal brine fluxes, trophic
conditions, biological-induced precipitation processes, water energy, substratumstability or instability and platform
geometry) that could have played a role in favoring specific features that characterize our Atlantic carbonates
relative to other known examples fromthe equatorial realm.We use the knowledge on the biota association
of St. Paul Rocks, small islets fromthe equatorial Atlantic, the onlymodern example of oceanic tectonic islands, to
compare present day with ancient assemblages.
We propose that equatorial upwelling and humid conditions, CO2 input and iron addition, related to the midocean
ridge, water energy and substratum instability may have created the conditions suitable for the predominance
of calcitic organisms over aragonitic corals in the Miocene tectonic islands of equatorial Atlantic. Moreover,
we do not exclude for the Vema paleoislands the influence of the fresh-water plumes from South
American rivers
Scalar gravitational waves from scalar-tensor gravity: production and response of interferometers
No full textCompositional evolution of the Laga and Cellino sandstones (Messinian-Lower Pliocene, Adriatic foredeep).
No full text
Entre Sardaigne et Afrique : Nouvelles recherches épigraphiques sur les processus de christianisation dans l’Antiquité tardive
No full textLa Provincia Sardinia fut conquise par Rome en 238 av. J.-C. et réduite en province en 227 av. J.-C. Les sources historiques aujourd’hui disponibles en soulignent souvent de manière explicite le rôle de grenier à blé, de terre riche en métaux précieux, et, en toutes périodes, de terre d’exil et de refuge. Ce qui n’est pas clairement explicité dans les sources mais qui apparaît en filigrane, c’est que la Sardinia fut utilisée par les Romains, surtout il est vrai dans les phases initiales de le..
On the general relativistic framework of the Sagnac effect
No full textThe Sagnac effect is usually considered as being a relativistic effect produced in an interferometer when the device is rotating. General relativistic explanations are known and already widely explained in many papers. Such general relativistic approaches are founded on Einstein’s equivalence principle (EEP), which states the equivalence between the gravitational “force” and the pseudo-force experienced by an observer in a non-inertial frame of reference, included a rotating observer. Typically, the authors consider the so-called Langevin-Landau-Lifschitz metric and the path of light is determined by null geodesics. This approach partially hides the physical meaning of the effect. It seems indeed that the light speed varies by c± ωr in one or the other direction around the disk. In this paper, a slightly different general relativistic approach will be used. The different “gravitational field” acting on the beam splitter and on the two rays of light is analyzed. This different approach permits a better understanding of the physical meaning of the Sagnac effect
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