Maximal-entropy random walks in complex networks with limited information

J.G.-G. was supported by MICINN through the Ramon y Cajal program and by grants FIS2008-01240 and MTM2009-13848

Entanglement properties of degenerate four-wave mixing of matter-waves in a periodic potential

In a recent experiment Campbell et al. [Phys. Rev. Lett. 96, 020406 (2006)] observed degenerate four-wave mixing of matter-waves in a one-dimensional optical lattice, a process with potential for generating entanglement among atoms. We analyse the essential quantum features of the experiment to show that entanglement is created between the quadratures of the two scattered atomic clouds and is a true many-body (rather than two-body) effect. We demonstrate a significant violation of entanglement inequalities that is robust to a moderate level of coherent seeding. The system is thus a promising candididate for generating macroscopically entangled atomic samples.Comment: 4 pages, 3 figure

Detecting phonons and persistent currents in toroidal Bose-Einstein condensates by means of pattern formation

We theoretically investigate the dynamic properties of a Bose-Einstein condensate in a toroidal trap. A periodic modulation of the transverse confinement is shown to produce a density pattern due to parametric amplification of phonon pairs. By imaging the density distribution after free expansion one obtains i) a precise determination of the Bogoliubov spectrum and ii) a sensitive detection of quantized circulation in the torus. The parametric amplification is also sensitive to thermal and quantum fluctuations.Comment: 4 pages, 4 figures; new figures, revised version to appear as a Rapid Communication in Physical Review

Do personality traits and self-regulatory processes affect decision-making tendencies?

Objective: This research attempted to clarify the role played by personality traits and self-regulated motivation in affecting decision-making tendencies. Method: Study 1 (n = 209) examined whether the Big Five personality traits predict minimising, maximising, and satisficing tendencies; Study 2 (n = 460) tested the mediating role of self-regulatory orientations in the relationship between personality traits and decision-making tendencies by performing structural equation modelling with latent variables. Results: Conscientiousness emerged as the strongest positive predictor of maximising, whereas openness to experience, conscientiousness, and agreeableness emerged as negative predictors of satisficing. As for the mediational model, both locomotion and assessment played a role in mediating the relationships between the personality traits and decision-making tendencies. Conclusions: This research provided interesting insights into the underlying motivations and strategies that lead individuals to maximise, satisfice, or minimise

Understanding mobility in a social petri dish

Despite the recent availability of large data sets on human movements, a full understanding of the rules governing motion within social systems is still missing, due to incomplete information on the socio-economic factors and to often limited spatio-temporal resolutions. Here we study an entire society of individuals, the players of an online-game, with complete information on their movements in a network-shaped universe and on their social and economic interactions. Such a "socio-economic laboratory" allows to unveil the intricate interplay of spatial constraints, social and economic factors, and patterns of mobility. We find that the motion of individuals is not only constrained by physical distances, but also strongly shaped by the presence of socio-economic areas. These regions can be recovered perfectly by community detection methods solely based on the measured human dynamics. Moreover, we uncover that long-term memory in the time-order of visited locations is the essential ingredient for modeling the trajectories

Validation of the Internet Gaming Disorder Scale - Short-Form (IGDS9-SF) in an Italian-speaking sample

Background and aims: The inclusion of Internet Gaming Disorder (IGD) in Section III of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders has increased the interest of researchers in the development of new standardized psychometric tools for the assessment of such a disorder. To date, the nine-item Internet Gaming Disorder Scale - Short-Form (IGDS9-SF) has only been validated in English, Portuguese, and Slovenian languages. Therefore, the aim of this investigation was to examine the psychometric properties of the IGDS9-SF in an Italian-speaking sample. Methods: A total of 757 participants were recruited to the present study. Confirmatory factor analysis and multi-group analyses were applied to assess the construct validity. Reliability analyses comprised the average variance extracted, the standard error of measurement, and the factor determinacy coefficient. Convergent and criterion validities were established through the associations with other related constructs. The receiver operating characteristic curve analysis was used to determine an empirical cut-off point. Results: Findings confirmed the singlefactor structure of the instrument, its measurement invariance at the configural level, and the convergent and criterion validities. Satisfactory levels of reliability and a cut-off point of 21 were obtained. Discussion and conclusions: The present study provides validity evidence for the use of the Italian version of the IGDS9-SF and may foster research into gaming addiction in the Italian context

A pulsed atomic soliton laser

It is shown that simultaneously changing the scattering length of an elongated, harmonically trapped Bose-Einstein condensate from positive to negative and inverting the axial portion of the trap, so that it becomes expulsive, results in a train of self-coherent solitonic pulses. Each pulse is itself a non-dispersive attractive Bose-Einstein condensate that rapidly self-cools. The axial trap functions as a waveguide. The solitons can be made robustly stable with the right choice of trap geometry, number of atoms, and interaction strength. Theoretical and numerical evidence suggests that such a pulsed atomic soliton laser can be made in present experiments.Comment: 11 pages, 4 figure

Sportspersonship in martial arts.

Studies on psychological outcomes related to individual differences have increased showing contradictory results, especially in martial arts. The difficulty to provide conclusive evidence for the psychological outcomes of martial arts practice and to determine if and to what extent martial arts trainings explain the above mentioned effects needs a more in-depth analysis of those dispositional aspects which can impact adaptive behaviors in terms of sportspersonship. Since no studies on sportspersonship and goal orientations has been carried out in the specific context of martial arts, the current research aimed at examining the role of goal orientations and trait aggressiveness as predictors of sportspersonship. A cross-sectional study was conducted. 389 Italian martial artists (Mage = 29.60, SD = 9.22) completed a questionnaire composed of four sections: a socio-anagraphic section, the Multidimensional Sportspersonship Orientations Scale, the Task and Ego Orientation in Sport Questionnaire, and the Aggression Questionnaire. Descriptive and casual analyses were applied to data. The expected hypotheses were generally confirmed. Results suggested that ego orientation and trait aggressiveness negatively predicted sportspersonship, whereas task orientation positively predicted a sportspersonship attitude. In sum, this research contributed to a better identification of the dispositional factors which prevent antisocial behaviors, especially in the context of martial arts

Decisional procrastination in academic settings: The role of metacognitions and learning strategies

Nowadays, university students suffer from a broad range of problems, such as educational underachievement or the inability to control themselves, that lead to procrastination as a consequence. The present research aimed at analyzing the determinants of decisional procrastination among undergraduate students and at assessing a path model in which self regulated learning strategies mediated the relationship between metacognitive beliefs about procrastination and decisional procrastination. 273 students from Southern Italy filled out a questionnaire composed by: the socio-demographic section, the Metacognitive Beliefs About Procrastination Questionnaire, the procrastination subscale of the Melbourne Decision Making Questionnaire, and the Anxiety, the Time Management, and the Information Processing subscales of the Learning and Study Strategies Inventory. Results showed that the relationship between negative and positive metacognitive beliefs about procrastination and decisional procrastination was mediated only by time management and anxiety. Such findings underlined the crucial role played by learning strategies in predicting the tendency to delay decisional situations and in mediating the relationship between metacognitive beliefs about procrastination and decisional procrastination

Quantum corrections to the dynamics of interacting bosons: beyond the truncated Wigner approximation

We develop a consistent perturbation theory in quantum fluctuations around the classical evolution of a system of interacting bosons. The zero order approximation gives the classical Gross-Pitaevskii equations. In the next order we recover the truncated Wigner approximation, where the evolution is still classical but the initial conditions are distributed according to the Wigner transform of the initial density matrix. Further corrections can be characterized as quantum scattering events, which appear in the form of a nonlinear response of the observable to an infinitesimal displacement of the field along its classical evolution. At the end of the paper we give a few numerical examples to test the formalism.Comment: published versio