294 research outputs found
Superfluid hydrodynamics of polytropic gases:dimensional reduction and sound velocity
Motivated by the fact that two-component confined fermionic gases in
Bardeen-Cooper-Schrieffer-Bose-Einstein condensate (BCS-BEC) crossover can be
described through an hydrodynamical approach, we study these systems - both in
the cigar-shaped configuration and in the disk-shaped one - by using a
polytropic Lagrangian density. We start from the Popov Lagrangian density and
obtain, after a dimensional reduction process, the equations that control the
dynamics of such systems. By solving these equations we study the sound
velocity as a function of the density by analyzing how the dimensionality
affects this velocityComment: Accepted for publication in J. Phys. A: Math. Theo
From particles to firms: On the kinetic theory of climbing up evolutionary landscapes
This paper constitutes the first attempt to bridge the evolutionary theory in economics and the theory of active particles in mathematics. It seeks to present a kinetic model for an evolutionary formalization of economic dynamics. The new derived mathematical representation intends to formalize the processes of learning and selection as the two fundamental drivers of evolutionary environments [G. Dosi, M.-C. Pereira and M.-E. Virgillito, The footprint of evolutionary processes of learning and selection upon the statistical properties of industrial dynamics, Ind. Corp. Change, 26 (2017) 187-210]. To coherently represent the aforementioned properties, the kinetic theory of active particles [N. Bellomo, A. Bellouquid, L. Gibelli and N. Outada, A Quest Towards a Mathematical Theory of Living Systems (Birkhäuser-Springer, 2017)] is here further developed, including the complex interaction of two hierarchical functional subsystems. Modeling and simulations enlighten the predictive ability of the approach. Finally, we outline the potential avenues for future research.Fil: Bellomo, Nicola. Universidad de Granada; España. Politecnico di Torino; ItaliaFil: Dosi, Giovanni. Sant'anna Scuola Universitaria Superiore Pisa; ItaliaFil: Knopoff, Damián Alejandro. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba. Centro de Investigación y Estudios de Matemática. Universidad Nacional de Córdoba. Centro de Investigación y Estudios de Matemática; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, AstronomÃa y FÃsica; ArgentinaFil: Virgillito, Maria Enrica. Sant'anna Scuola Universitaria Superiore Pisa; Itali
Revisiting paramagnetic relaxation enhancements in slowly rotating systems: how long is the long range?
Cross-relaxation terms in paramagnetic systems that reorient rigidly with slow tumbling times can increase the effective longitudinal relaxation rates of protons of more than 1 order of magnitude. This is evaluated by simulating the time evolution of the nuclear magnetization using a complete relaxation rate-matrix approach. The calculations show that the Solomon dependence of the paramagnetic relaxation rates on the metal–proton
distance (as r−6) can be incorrect for protons farther than 15 Å from the metal and thus can cause sizable errors in R1-derived distance restraints used, for instance, for protein structure determination. Furthermore, the chemical exchange of these protons with bulk water protons can enhance the relaxation rate of the solvent protons by far more than expected from the paramagnetic Solomon equation. Therefore, it may contribute significantly to the water proton relaxation rates measured at magnetic resonance imaging (MRI) magnetic fields in the presence of slow-rotating nanoparticles containing paramagnetic ions and a large number of exchangeable surface protons
Quality of Life: Effects of Physical Activity in an Anthropometric, Cognitive and Psychosocial Background, and Variation of Odontoiatric Parameters
The "Quality of Life" project arises from the need to observe and define the existing interconnection between a "healthy" lifestyle and the quality of life perceived by people. Starting from the W.H.O. (World Health Organization) definitions of quality of life and health, and analyzing the studies that describe the benefits of both movement physical and mental, a protocol three months has been set for the pursuit of a diet and personalized training. For this purpose, 20 healthy subjects from the 1st year of the Physiotherapy degree, who had never practiced sports at an agonistic level, have been recruited. All individuals were subject to initial evaluations to define psycho-physical wellbeing, then they have been divided into two groups: the first group, defined as experimental, followed the protocol for the duration of the study, while the second, was only subject to evaluation. At the end of the three months period, the subjects of both groups were evaluated twice, the first immediately after the last training session, the second was evaluated one month from the latter. The final evaluation aimed at verifying a possible conservative effect on modification of experimental group parameters, even when physical activity and nutrition were not supervised by us. The ultimate goal of the project was to specifically analyze, after three months, the changes in cognitive memory capacity and concentration, the stress experienced in work or study, and psycho-physical wellbeing perceived by the concerned subjects. Data collected during the three evaluations showed that, in the experimental group, as our scientific protocol has altered all these parameters in terms of quality of life in positive terms, modifications are susceptible to changes in the event that physical activity and proper nutrition are not followed
Update on intensive motor training in spinocerebellar ataxia: time to move a step forward?:
Some evidence suggests that high-intensity motor training slows down the severity of spinocerebellar ataxia. However, whether all patients might benefit from these activities, and by which activity, and the underlying mechanisms remain unclear. We provide an update on the effect and limitations of different training programmes in patients with spinocerebellar ataxias. Overall, data converge of the finding that intensive training is still based either on conventional rehabilitation protocols or whole-body controlled videogames ("exergames"). Notwithstanding the limitations, short-term improvement is observed, which tends to be lost once the training is stopped. Exergames and virtual reality can ameliorate balance, coordination, and walking abilities, whereas the efficacy of adapted physical activity, gym, and postural exercises depends on the disease duration and severity. In conclusion, although a disease-modifying effect has not been demonstrated, constant, individually tailored, high-intensity motor training might be effective in patients with degenerative ataxia, even in those with severe disease. These approaches may enhance the remaining cerebellar circuitries or plastically induce compensatory networks. Further research is required to identify predictors of training success, such as the type and severity of ataxia and the level of residual functioning
From microscopic taxation and redistribution models to macroscopic income distributions
We present here a general framework, expressed by a system of nonlinear
differential equations, suitable for the modelling of taxation and
redistribution in a closed (trading market) society. This framework allows to
describe the evolution of the income distribution over the population and to
explain the emergence of collective features based on the knowledge of the
individual interactions. By making different choices of the framework
parameters, we construct different models, whose long-time behavior is then
investigated. Asymptotic stationary distributions are found, which enjoy
similar properties as those observed in empirical distributions. In particular,
they exhibit power law tails of Pareto type and their Lorenz curves and Gini
indices are consistent with some real world ones.Comment: 12 pages, 4 figures. Version submitted to Physica A on Feb 15, 201
an ecological study on the association between characteristics of hospital units and the risk of occupational injuries and adverse events on the example of an italian teaching hospital
OBJECTIVES: We explored the association of workplace characteristics with occupational injuries and adverse events in an Italian teaching hospital. MATERIAL AND METHODS: This ecological study was conducted using data routinely collected in the University Hospital of Udine, Northeastern Italy. Poisson regression models were used to investigate, at the hospital unit level, the association between 5 outcomes, including: occupational injuries, patient falls, medication errors, other adverse events and near-misses, and various characteristics of the units. RESULTS: The proportion of female workers in a unit, the average number of sick-leave days and of overtime hours, the number of medical examinations requested by employees, and being a surgical unit were significantly associated with some of the outcomes. CONCLUSIONS: Despite ecological nature of the study, which does not allow for inferences to be drawn at the individual level, the results of our study provide useful clues to support strategies and interventions directed towards healthier work environments and better patient care in hospitals. Language: e
Non-invAsive VentIlation for early General wArd respiraTory failurE (NAVIGATE):A multicenter randomized controlled study. Protocol and statistical analysis plan
Few randomized trials have evaluated the use of non-invasive ventilation (NIV) for early acute respiratory failure (ARF) in non-intensive care unit (ICU) wards. The aim of this study is to test the hypothesis that early NIV for mild-moderate ARF in non-ICU wards can prevent development of severe ARF
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