86,662 research outputs found
Scardigli studioso e maestro. Un breve profilo scientifico e maieutico
No full textBiographic and scholarly notes on Piergiuseppe Scardigli, late professor and researcher of Germanic philology of international prominence
La Société digitale, par P.A. Mercier, F. Plassard, V. Scardigli
No full textLaulan Anne-Marie. La Société digitale, par P.A. Mercier, F. Plassard, V. Scardigli. In: Communication et langages, n°62, 4ème trimestre 1984. pp. 123-124
Generalized uncertainty principle, extra-dimensions and holography
No full textWe consider Uncertainty Principles which take into account the role of gravity and the possible existence of extra spatial dimensions. Explicit expressions for such Generalized Uncertainty Principles in 4+n dimensions are given and their holographic properties investigated. In particular, we show that the predicted number of degrees of freedom enclosed in a given spatial volume matches the holographic counting only for one of the available generalizations and without extra dimensions
Perihelion Precession and Generalized Uncertainty Principle
No full textWe compute the corrections to the Schwarzschild metric necessary to reproduce the Hawking temperature derived from a Generalized Uncertainty Princi- ple (GUP), so that the GUP deformation parameter is directly linked to the deforma- tion of the metric. Using this modified Schwarzschild metric, we compute corrections to the standard General Relativistic predictions for the perihelion precession for plan- ets in the solar system. This analysis allows us to set bounds for the GUP deformation parameter from well-known astronomical measurements
Artificial Intelligence Versus Natural Intelligence
No full textThis book centers around a dialogue between Roger Penrose and Emanuele Severino about one of most intriguing topics of our times, the comparison of artificial intelligence and natural intelligence, as well as its extension to the notions of human and machine consciousness. Additional insightful essays by Mauro D’Ariano, Federico Faggin, Ines Testoni, Giuseppe Vitiello and an introduction of Fabio Scardigli complete the book and illuminate different aspects of the debate. Although from completely different points of view, all the authors seem to converge on the idea that it is almost impossible to have real “intelligence” without a form of “consciousness”. In fact, consciousness, often conceived as an enigmatic “mirror” of reality (but is it really a mirror?), is a phenomenon under intense investigation by science and technology, particularly in recent decades. Where does this phenomenon originate from (in humans, and perhaps also in animals)? Is it reproducible on some “device”? Do we ..
E1-Ngn2/Cre is a new line for regional activation of Cre recombinase in the developing CNS
No full textWe generated a transgenic mouse line named
E1-Ngn2/Cre that expresses Cre recombinase and GFP
under the control of the E1 enhancer element of the gene
Ngn2 (Scardigli et al.: Neuron 31:203–217, 2001). Crerecombinase activity and GFP fluorescence are consistent
with the reported expression pattern controlled by
the E1-Ngn2 enhancer. Recombination was detected in
the progenitor domains p1 and p2 in the ventricular zone
of the neural tube and in distinct domains of the pretectum,
the dorsal and ventral thalamus, the tegmentum of
the mesencephalon, and the hindbrain. In the developing
cortex, Cre-recombinase activity is confined to a subpopulation
of progenitors predominantly in the region of
the ventral and lateral pallium. The E1-Ngn2/Cre mouse
line thus provides an excellent novel tool for a regionspecific
conditional mutagenesis in the developing CNS
Generalized uncertainty principle and asymptotically safe gravity
No full textWe present a procedure to link the deformation parameter \beta of the generalized uncertainty principle (GUP) to the two free parameters \omega and \gamma of the running Newtonian coupling constant of the asymptotically safe gravity program. To this aim, we compute the Hawking temperature of a black hole in two different ways. The first way involves the use of the GUP in place of the Heisenberg uncertainty relations, and therefore we get a deformed Hawking temperature containing the parameter \beta
. The second way involves the deformation of the Schwarzschild metric due to the Newtonian coupling constant running according to the asymptotically safe gravity prescription. The comparison of the two techniques yields a relation between
\beta and \omega, \gamma. As a particular case, we discuss also the so-called \zeta -model. The relations between \beta and ̃ omega, \zeta allow us to transfer upper bounds from one parameter to the others
Gravitational tests of the generalized uncertainty principle
No full textWe compute the corrections to the Schwarzschild metric necessary to reproduce the Hawking temperature derived from a generalized uncertainty principle (GUP), so that the GUP deformation parameter is directly linked to the deformation of the metric. Using this modified Schwarzschild metric, we compute corrections to the standard general relativistic predictions for the light deflection and perihelion precession, both for planets in the solar system and for binary pulsars. This analysis allows us to set bounds for the GUP deformation parameter from well-known astronomical measurements
Is the equivalence principle violated by the generalized uncertainty principle and holography in a brane-world?
No full textIt has been recently debated whether a class of generalized uncertainty principles that include gravitational sources of error are compatible with the holographic principle in models with extra spatial dimensions. We had in fact shown elsewhere that the holographic scaling is lost when more than four space-time dimensions are present. However, we shall show here that the validity of the holographic counting can be maintained also in models with extra spatial dimensions, but at the intriguing price that the equivalence principle for a point-like source be violated and the inertial mass differ from the gravitational mass in a specific non-trivial way
- …
