Variational approach for the quantum Zakharov system

The quantum Zakharov system is described in terms of a Lagrangian formalism. A time-dependent Gaussian trial function approach for the envelope electric field and the low-frequency part of the density fluctuation leads to a coupled, nonlinear system of ordinary differential equations. In the semiclassic case, linear stability analysis of this dynamical system shows a destabilizing r\^ole played by quantum effects. Arbitrary value of the quantum effects are also considered, yielding the ultimate destruction of the localized, Gaussian trial solution. Numerical simulations are shown both for the semiclassic and the full quantum cases.Comment: 6 figure

A Note on the Toda Criterion for Interacting Dipole-Quadrupole Vibrations

The Toda criterion of the Gaussian curvature is applied to calculate analytically the transition energy from regular to chaotic motion in a schematic model describing the interaction between collective dipole and quadrupole modes in atomic nuclei.Comment: Latex, 9 pages, 2 figures (available upon request), to be published in Modern Physics Letters

Different Facets of Chaos in Quantum Mechanics

Nowadays there is no universally accepted definition of quantum chaos. In this paper we review and critically discuss different approaches to the subject, such as Quantum Chaology and the Random Matrix Theory. Then we analyze the problem of dynamical chaos and the time scales associated with chaos suppression in quantum mechanics. Summary: 1. Introduction 2. Quantum Chaology and Spectral Statistics 3. From Poisson to GOE Transition: Comparison with Experimental Data 3.1 Atomic Nuclei 3.2 The Hydrogen Atom in the Strong Magnetic Field 4. Quantum Chaos and Field Theory 5. Alternative Approaches to Quantum Chaos 6. Dynamical Quantum Chaos and Time Scales 6.1 Mean-Field Approximation and Dynamical Chaos 7. ConclusionsComment: RevTex, 25 pages, 7 postscript figures, to be published in Int. J. Mod. Phys.

From the Greek theater to the mind: the opportunities of the mask

From some elements of the mask in the ancient Greek theatre which are expressed in the current civilization and psychic economy, it is possible to identify positive some psychological functions that can be performed by the mask, especially the self-protection and the possibility to put into play unknown parts of the self, therefore meeting the diveristy within and outside us. It's highlighted how the ongoing simplification in the mask could on one side offer a supporting screen in a society that multiplies images and amplifies the fragmentation risk, and on the other could reduce the risk of distortions of one own’s image in the other’s eyes. Therefore, the problem of believable speakers on which one could put his epistemophilic trust is arised and this is linked to the theme of openness to the future, to the persistence and the necessity of sharing, of relationship. Namely, it’s highlighted the possibility offered by the mask of experimenting what is not yet, but is present in the desire, as a sort of anticipating background that, instead of being closed in a mental fantasy or in a daydream, is played in the reality (virtual?). It's underlined how this function stays in a delicate balance between experimentation – the “carnival” function – and the gamble and its collocation could therefore fluctuate between the work-in-progress frame and the suicidary one, in which parts of the self can be integrated rather than reduced. Finally, highlighting the dimension of beauty and culture, recalled from the Greek theatre mask, it’s adfirmed the importance of these values, translated as play and care systems, a transitional space, in the psychological and psychotherapy fields. The explained themes are lastly evoked and exemplified through the illustration of a clinical case

Genetic parameters of dairy traits in the Alpine and Saanen goat breeds

Genetic parameters for milk, fat and protein yields, and fat and protein contents, were estimated for the Alpine and Saanen goat breeds using an animal model. Edited data included first lactations of 33 431 Alpine and 20 700 Saanen goats kidding in 1996 and 1997. Heritability values ranged from 0.32 to 0.40 for yields and from 0.50 to 0.60 for solid contents. The main feature observed on genetic correlations was a low genetic opposition between milk yield and fat content (about - 0.17) with a high genetic association between fat yields and fat contents (up to +0.56). Although the differences between genetic parameters of both breeds were rather low, the estimates suggest a higher potential for genetic progress in protein content and protein yield in the Alpine breed, and a higher potential for joint genetic progress in milk yield and fat content in the Saanen breed

Spin solitons in magnetized pair plasmas

A set of fluid equations, taking into account the spin properties of the electrons and positrons in a magnetoplasma, are derived. The magnetohydrodynamic limit of the pair plasma is investigated. It is shown that the microscopic spin properties of the electrons and positrons can lead to interesting macroscopic and collective effects in strongly magnetized plasmas. In particular, it is found that new Alfvenic solitary structures, governed by a modified Korteweg-de Vries equation, are allowed in such plasmas. These solitary structures vanish if the quantum spin effects are neglected. Our results should be of relevance for astrophysical plasmas, e.g. in pulsar magnetospheres.Comment: 7 page

A new strategy for the seismic assessment of existing RC buildings

This paper presents a new strategy for the seismic assessment of existing Reinforced Concrete (RC) buildings. The proposed method is based on a two steps approach. A field survey of some buildings is first developed torecord their geometrical and mechanical characteristics; such survey is then enriched with information based on regulations and practical rules used during construction: the result of this step is the definition of homogeneus classes of buildings representing typical structures. The second step is based on the assessment of the seismic capacity of these structures using both refined models and parametric analysis: the outcomes can be extended to the defined classes to obtain vulnerability maps. A first application of the proposed strategy was made in Catania and the results of that study on an urban area, characterized by RC buildings constructed in the '60s and '70s without seismic provisions, are briefly presented

Causes of hospitalization among extra-European Union children in a large hospital of Northern Italy, in a five-year observation period

The hospitalizations of 1,239 patients aged 14 years or less and immigrated from extra-European Union countries in Italy were assessed in the 6-year period, from 1999 to 2004. The main demographic and clinical features were analyzed according to several variables, also distiguishing patients aged less than one year, from those aged 1-14 years. The introduction of a deed of indemnity law in 2001 profoundly changed the pattern of admissions and health care needs and exploitation during subsequent years, leading to a massive regularization of clandestine immigrants