17,273 research outputs found
Alcohol Consumption and Binge Drinking Among Young Adults Aged 20–30 Years in Lisbon, Portugal
Background: Over the past decade, the changes to the pattern of alcohol consumption in Portugal, in particular among young people with heavy episodic drinking (binge drinking), are well documented. However, there are limited studies in individuals aged between 20 and 30 years, which is an important period of transition into adulthood where binge drinking can negatively influence the resolution of developmental tasks. Therefore, this study aims at analyzing the pattern of alcohol consumption and binge drinking among young adults aged between 20 and 30 years living in the municipality of Lisbon.
Methodology: This is a quantitative, descriptive correlational study using a convenience sample composed of 259 individuals. We used the Alcohol Use Disorders Identification Test for data collection.
Results: Among the sampled subjects, 19.3% of them reported being nondrinkers. Among the alcohol-drinking subjects (N = 209), 61.3% reported binge drinking behaviors. We found a higher percentage of binge drinkers among vocational training students than among university students, as well as a relatively higher percentage of women. In both cases, we found no statistically significant differences. Within the total sample, 10.8% reported hazardous or harmful consumption, with men showing greater hazardous consumption.
Conclusions: Although approximately one fifth of the sampled subjects reported being nondrinkers, the percentage of binge drinkers in this study was significantly higher than that reported in other studies. We also found that binge drinking is more common among vocational training students, although this difference was not statistically significant. Further studies are needed on this age group and in nonacademic settings
Non-Perturbatively Improved Quenched Hadron Spectroscopy
We make a quenched lattice simulation of hadron spectroscopy at beta=6.2 with
the Wilson action non-perturbatively improved. With respect to the unimproved
case, the estimate of the lattice spacing is less influenced by the choice of
input hadron masses. We study also the effects of using an improved quark mass
in the fits to the dependence of hadron masses upon quark masses.Comment: 12 pages, including 5 postscript figure
First- and second-order phase transitions in Ising models on small world networks, simulations and comparison with an effective field theory
We perform simulations of random Ising models defined over small-world
networks and we check the validity and the level of approximation of a recently
proposed effective field theory. Simulations confirm a rich scenario with the
presence of multicritical points with first- or second-order phase transitions.
In particular, for second-order phase transitions, independent of the dimension
d_0 of the underlying lattice, the exact predictions of the theory in the
paramagnetic regions, such as the location of critical surfaces and correlation
functions, are verified. Quite interestingly, we verify that the
Edwards-Anderson model with d_0=2 is not thermodynamically stable under graph
noise.Comment: 12 pages, 12 figures, 1 tabl
The fractional volatility model : no-arbitrage, leverage and completeness
When the volatility process is driven by fractional noise one obtains a model which is consistent with the empirical market data. Depending on whether the stochasticity generators of log-price and volatility are independent or are the same, two versions of the model are obtained with different leverage behaviors. Here, the no-arbitrage and completeness properties of the models are rigorously studied
Optical properties of charged quantum dots doped with a single magnetic impurity
We present a microscopic theory of the optical properties of self-assembled
quantum dots doped with a single magnetic manganese (Mn) impurity and
containing a controlled number of electrons. The single-particle electron and
heavy-hole electronic shells are described by two-dimensional harmonic
oscillators. The electron-electron, electron-hole Coulomb as well as the
short-range electron spin-Mn spin and hole spin-Mn spin contact exchange
interactions are included. The electronic states of the photo-excited
electron-hole-Mn complex and of the final electron-Mn complex are expanded in a
finite number of configurations and the full interacting Hamiltonian is
diagonalized numerically. The emission spectrum is predicted as a function of
photon energy for a given number of electrons and different number of confined
electronic quantum dot shells. We show how emission spectra allow to identify
the number of electronic shells, the number of electrons populating these
shells and, most importantly, their spin. We show that electrons not
interacting directly with the spin of Mn ion do so via electron-electron
interactions. This indirect interaction is a strong effect even when Mn
impurity is away from the quantum dot center.Comment: 12 pages, 10 figure
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