999 research outputs found
Neutrino-Nucleus Quasi-Elastic Scattering in a Relativistic Model
A relativistic distorted-wave impulse-approximation model is applied to
neutral-current and charged-current quasi-elastic neutrino-nucleus scattering.
The effects of final state interactions are investigated and the sensitivity of
the results to the strange nucleon form factors is discussed in view of their
possible experimental determinationComment: 7 pages, 3 figures Proc. of the XXV International Workshop on Nuclear
Theory, 26 June- 1 July, 2006 Rila, Bulgari
Relativistic descriptions of final-state interactions in neutral-current neutrino-nucleus scattering at MiniBooNE kinematics
The analysis of the recent neutral-current neutrino-nucleus scattering cross
sections measured by the MiniBooNE Collaboration requires relativistic
theoretical descriptions also accounting for the role of final state
interactions. In this work we evaluate differential cross sections with the
relativistic distorted-wave impulse-approximation and with the relativistic
Green's function model to investigate the sensitivity to final state
interactions. The role of the strange-quark content of the nucleon form factors
is also discussed.Comment: 8 pages, 5 figure
Electron-induced proton knockout from neutron rich nuclei
We study the evolution of the \eep cross section on nuclei with increasing
asymmetry between the number of neutrons and protons. The calculations are done
within the framework of the nonrelativistic and relativistic distorted-wave
impulse approximation. In the nonrelativistic model phenomenological
Woods-Saxon and Hartree-Fock wave functions are used for the proton bound-state
wave functions, in the relativistic model the wave functions are solutions of
Dirac-Hartree equations. The models are first tested against experimental data
on Ca and Ca nuclei, and then they are applied to a set of
spherical calcium isotopes.Comment: 5 pages, 2 figures. contribution to the XIX International School on
Nuclear Physics, Neutron Physics and Applications, Varna (Bulgaria) September
19-25, 201
Power-laws in recurrence networks from dynamical systems
Recurrence networks are a novel tool of nonlinear time series analysis
allowing the characterisation of higher-order geometric properties of complex
dynamical systems based on recurrences in phase space, which are a fundamental
concept in classical mechanics. In this Letter, we demonstrate that recurrence
networks obtained from various deterministic model systems as well as
experimental data naturally display power-law degree distributions with scaling
exponents that can be derived exclusively from the systems' invariant
densities. For one-dimensional maps, we show analytically that is not
related to the fractal dimension. For continuous systems, we find two distinct
types of behaviour: power-laws with an exponent depending on a
suitable notion of local dimension, and such with fixed .Comment: 6 pages, 7 figure
Mean-field calculations of exotic nuclei ground states
We study the predictions of three mean-field theoretical approaches in the
description of the ground state properties of some spherical nuclei far from
the stability line. We compare binding energies, single particle spectra,
density distributions, charge and neutron radii obtained with non-relativistic
Hartree-Fock calculations carried out with both zero and finite-range
interactions, and with a relativistic Hartree approach which uses a
finite-range interaction. The agreement between the results obtained with the
three different approaches indicates that these results are more related to the
basic hypotheses of the mean-field approach rather than to its implementation
in actual calculations.Comment: 16 pages, 12 figures, 2 tables, accepted for publication in Physical
Review
Prevalenza della sclerosi multipla nell'isola d'Elba
OBIETTIVI: Calcolare la prevalenza della Sclerosi Multipla (SM) nell’isola d’Elba dal momento che non ci sono dati disponibili in letteratura.
METODI: L'isola d'Elba è l’isola più grande dell'Arcipelago Toscano. Al giorno di prevalenza, ovvero il 31/12/2010, la popolazione residente nell’isola era pari a 31.943 ab.
I casi di SM sono stati identificati consultando le cartelle cliniche dell’ospedale e dell’ambulatorio neurologico di riferimento dell’isola. Sono stati arruolati nello studio tutti i pazienti con diagnosi di SM secondo i criteri di McDonald, residenti nell’isola al giorno di prevalenza.
Sono stati calcolati i tassi di prevalenza grezzi e specifici (sesso e età) e il tasso standardizzato rispetto alla popolazione italiana del 2001. Gli intervalli di confidenza al 95% dei tassi di prevalenza sono stati calcolati assumendo una distribuzione di Poisson.
RISULTATI: Al giorno di prevalenza erano residenti nell’isola 42 soggetti con SM. Di questi il 40,5% era nato fuori dall’isola e 4 pazienti avevano origine sarda.
Il rapporto F:M è risultato pari a 2,8 e l’età media dei soggetti era di 49,8±12,6 anni.
Per quanto riguarda le forme di malattia, il 16,7% dei pazienti aveva una forma CIS, il 61,9% una RR, il 16,7% una SP e il 4,8% una PP. Il grado di disabilità (EDSS) è risultato correlato (trend crescente) con la forma di malattia: EDSS pari a 1,5 per le forme CIS, 2,0 per le RR e 6,0 per le SP e PP. La durata di malattia, in media, era di 15,0±9,8 anni, con un range tra 0 e 37 anni.
Il tasso di prevalenza grezzo è risultato pari a 131,5 (IC 95%: 99,8-177,7) per 100.000 (maschi 70,7; femmine 189,2 per 100.000). Il tasso di prevalenza standardizzato è risultato pari a 131,5 (IC 95%: 91,8-171,2) per 100.000.
Il tasso di prevalenza sesso età specifico mostra un picco, per entrambi i sessi, nella classe di età tra 45-54 anni, mentre non ci sono casi prima dei 15 anni.
Analizzando il periodo di latenza (ovvero la lunghezza in anni tra esordio dei sintomi e diagnosi di malattia) si osserva un trend negativo, statisticamente significativo, rispetto l’anno di esordio: infatti per i pazienti con esordio più recente, il periodo di latenza è diminuito rispetto a quello dei pazienti con esordio più remoto.
CONCLUSIONI: Essendo il primo studio effettuato nell’isola, non è possibile fare confronti con dati precedenti. Il valore di prevalenza osservato dovrebbe essere comunque in linea con l’attuale prevalenza dell’Italia continentale e comunque inferiore a quella stimata in Sardegna (Pugliatti, 2009)
Estimate of the theoretical uncertainty of the cross sections for nucleon knockout in neutral-current neutrino-oxygen interactions
Free nucleons propagating in water are known to produce gamma rays, which
form a background to the searches for diffuse supernova neutrinos and sterile
neutrinos carried out with Cherenkov detectors. As a consequence, the process
of nucleon knockout induced by neutral-current quasielastic interactions of
atmospheric (anti)neutrinos with oxygen needs to be under control at the
quantitative level in the background simulations of the ongoing and future
experiments. In this paper, we provide a quantitative assessment of the
uncertainty associated with the theoretical description of the nuclear cross
sections, estimating it from the discrepancies between the predictions of
different models.Comment: 7 pages, 2 figure
Cardiac Autonomic Effects of Yearly Athletic Retreats on Elite Basket Players. Usefulness of a Unitary Autonomic Nervous System Indicator
In most sports athletic performance is determined by a combination of hard and soft modifiable components, encompassing physical and psychological elements that can be assessed with modern techniques based respectively on simple friendly methods: analysis of HRV and questionnaires. Specifically a novel % rank Autonomic Nervous System Indicator (ANSI) seems particularly useful also in elite sports. In this investigation we assessed ANSI capacity to detect the expected changes in cardiac autonomic regulation induced in the Italian basketball team by the participation (18 subjects) to the yearly biweekly Alpine training summer camp. We observed that ANSI increased from 58.8 +/- 32.5 to 81.7 +/- 27.5 (at the end of training camp) and did not change further in the subsequent initial weeks of competition season (overall p < 0.001). Congruent changes were observed in non-linear indices. Concomitantly indices of somatic symptoms were slightly reduced just at the end of the alpine training. We conclude that analysis of HRV and questionnaires might offer a simple, useful technique to monitor changes in cardiac autonomic regulation and psychological state in elite athletes providing a convenient additional element to evaluation of training routines also in the fields
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