Spatial patterns mediated by subcritical and supercritical thermal fluctuations in the splay Fréedericksz transition

The magnetically induced splay Fréedericksz transition is reexamined to look for pattern forming phenomena slightly above or below criticality. By using our traditional scheme of stochastic nematodynamic equations, situations are, respectively, found of transient and permanent predominance of transversal periodicities (wave numbers) along the direction perpendicular to the initial orientation within the sample. The relevance of these predictions in relation with recent observations in the electrically driven splay Fréedericksz transition, and in general with other pattern forming phenomena, is stressed.

Patterns of cannabis use and prospective associations with health issues among young males.

BACKGROUND AND AIMS: To test prospective associations between cannabis disorder symptoms/frequency of cannabis use and health issues and to investigate stability versus transience in cannabis use trajectories. DESIGN: Two waves of data collection from the longitudinal Cohort Study on Substance Use Risk Factors (C-SURF). SETTING: A representative sample of young Swiss men in their early 20s from the general population. PARTICIPANTS: A total of 5084 young men (mean age 19.98 ± 1.19 years at time 1). MEASUREMENTS: Cannabis use (life-time use, frequency of use, cannabis disorder symptoms) and self-reported measures of health issues (depression, mental/physical health, health consequences) were assessed. Significant changes in cannabis use were tested using t-test/Wilcoxon's rank test for paired data. Cross-lagged panel models provided evidence regarding longitudinal associations between cannabis use and health issues. FINDINGS: Most of the participants (84.5%) remained in the same use category and cannabis use kept to similar levels at times 1 and 2 (P = 0.114 and P = 0.755; average of 15 ± 2.8 months between times 1 and 2). Cross-lagged panel models showed that cannabis disorder symptoms predicted later health issues (e.g. depression, β = 0.087, P < 0.001; health consequences, β = 0.045, P < 0.05). The reverse paths from health issues to cannabis disorder symptoms and the cross-lagged panel model between frequency of cannabis use and health issues were non-significant. CONCLUSIONS: Patterns of cannabis use showed substantial continuity among young Swiss men in their early 20s. The number of symptoms of cannabis use disorder, rather than the frequency of cannabis use, is a clinically important measure of cannabis use among young Swiss men.

Preimplantation genetic diagnosis (PGD) for HLA typing: bases for setting up an open international collaboration when PGD is not available.

In severe forms of Diamond-Blackfan anemia, preimplantation genetic diagnosis (PGD) of histocompatibility leukocyte antigen-compatible embryos for enabling the next sibling in the family to be a stem-cell transplantation donor constitutes the sole lasting cure capable of terminating the enduring need for iterative transfusions. We report here an open collaboration between two renowned institutions to provide a family desiring this treatment even though they resided where the preimplantation genetic diagnosis procedure is banned.

Non-verbal behavioural patterns in trilogue play transitions and family alliances

This case study focuses on non-verbal behaviour in father-mother-infant triads. Analyses were done on transitional moments during which the partners exchanged an active role for a participant-observer role, or vice versa. Transitions are known to be crucial moments for revealing familial transactional mechanisms. Our sample was comprised of six non-clinical families, characterized by different types of functional or problematic alliances (which is the degree of coordination between the partners). Our methodology included micro-analysis of body and gaze formations, facial expressions, and so on. Data were analysed using the research package 'THEME' for the detection of hidden patterns. Different types of non-verbal patterns were found, which may be prototypes corresponding to the different types of alliance. The patterns of the families with high alliances had a more elaborate construction and were more efficient for the concluding of transitions than the patterns of families with low alliances, which were either elementary or laborious. (PsycINFO Database Record (c) 2006 APA, all rights reserved) (journal abstract)

Transient patterns in nematic liquid crystals: Domain-wall dynamics

We study the dynamics of the late stages of the Fréedericksz transition in which a periodic transient pattern decays to a final homogeneous state. A stability analysis of an unstable stationary pattern is presented, and equations for the evolution of the domain walls are obtained. Using results of previous theories, we analyze the effect that the specific dynamics of the problem, incorporating hydrodynamic couplings, has on the expected logarithmic domain growth law.

Dynamics of turing patterns under spatiotemporal forcing

We study, both theoretically and experimentally, the dynamical response of Turing patterns to a spatiotemporal forcing in the form of a traveling-wave modulation of a control parameter. We show that from strictly spatial resonance, it is possible to induce new, generic dynamical behaviors, including temporally modulated traveling waves and localized traveling solitonlike solutions. The latter make contact with the soliton solutions of Coullet [Phys. Rev. Lett. 56, 724 (1986)] and generalize them. The stability diagram for the different propagating modes in the Lengyel-Epstein model is determined numerically. Direct observations of the predicted solutions in experiments carried out with light modulations in the photosensitive chlorine dioxide-iodine-malonic acid reaction are also reported.

Travelling-stripe forcing generates hexagonal patterns

We study the response of Turing stripe patterns to a simple spatiotemporal forcing. This forcing has the form of a traveling wave and is spatially resonant with the characteristic Turing wavelength. Experiments conducted with the photosensitive chlorine dioxide-iodine-malonic acid reaction reveal a striking symmetry-breaking phenomenon of the intrinsic striped patterns giving rise to hexagonal lattices for intermediate values of the forcing velocity. The phenomenon is understood in the framework of the corresponding amplitude equations, which unveils a complex scenario of dynamical behaviors.

Traveling waves and nonequilibrium stationary patterns in two-component reactive Langmuir monolayers

A simple kinetic model of a two-component phase-separating Langmuir monolayer with a chemical reaction is proposed. Its analysis and numerical simulations show that nonequilibrium periodic stationary structures and patterns of traveling stripes can spontaneously develop. The nonequilibrium phase diagram of this system is constructed and the properties of the patterns are discussed.

Self-organizing propagation patterns from dynamic self-assembly in monolayers

Propagation of localized orientational waves, as imaged by Brewster angle microscopy, is induced by low intensity linearly polarized light inside axisymmetric smectic-C confined domains in a photosensitive molecular thin film at the air/water interface (Langmuir monolayer). Results from numerical simulations of a model that couples photoreorientational effects and long-range elastic forces are presented. Differences are stressed between our scenario and the paradigmatic wave phenomena in excitable chemical media.

Patterns of gravity induced aggregate migration during casting of fluid concretes

In this paper, aggregate migration patterns during fluid concrete castings are studied through experiments, dimensionless approach and numerical modeling. The experimental results obtained on two beams show that gravity induced migration is primarily affecting the coarsest aggregates resulting in a decrease of coarse aggregates volume fraction with the horizontal distance from the pouring point and in a puzzling vertical multi-layer structure. The origin of this multi layer structure is discussed and analyzed with the help of numerical simulations of free surface flow. Our results suggest that it finds its origin in the non Newtonian nature of fresh concrete and that increasing casting rate shall decrease the magnitude of gravity induced particle migration. (C) 2012 Elsevier Ltd. All rights reserved.

Performance anxiety : cardiorespiratory activity in high- and low-anxious professional music students in a performance situation

Questionnaire studies indicate that high-anxious musicians may suffer from hyperventilation symptoms before and/or during performance. Reported symptoms include amongst others shortness of breath, fast or deep breathing, dizziness and thumping heart. A self-report study by Widmer, Conway, Cohen and Davies (1997) shows that up to seventy percent of the tested highly anxious musicians are hyperventilators during performance. However, no study has yet tested if these self-reported symptoms reflect actual cardiorespiratory changes just before and during performance. Disturbances in breathing patterns and hyperventilation may negatively affect the performance quality in stressful performance situations. The main goal of this study is to determine if music performance anxiety is manifest physiologically in specific correlates of cardiorespiratory activity. We studied 74 professional music students of Swiss Music Universities divided into two groups (high- and lowanxious) based on their self-reported performance anxiety (State-Trait Anxiety Inventory by Spielberger). The students were tested in three distinct situations: baseline, performance without audience, performance with audience. We measured a) breathing patterns, end-tidal carbon dioxide, which is a good non-invasive estimator for hyperventilation, and cardiac activation and b) self-perceived emotions and self-perceived physiological activation. Analyses of heart rate, respiratory rate, self-perceived palpitations, self-perceived shortness of breath and self-perceived anxiety for the 15 most and the 15 least anxious musicians show that high-anxious and low-anxious music students have a comparable physiological activation during the different measurement periods. However, highanxious music students feel significantly more anxious and perceive significantly stronger palpitations and significantly stronger shortness of breath just before and during a public performance. The results indicate that low- and high-anxious music students a) do not differ in the considered physiological responses and b) differ in the considered self-perceived physiological symptoms and the selfreported anxiety before and/or during a public performance.

Regional integration and specialisation patterns in Spain

The aim of this paper is to analyse how economic integration in Europe has affected industrial geographical concentration in Spain and explain what the driving forces behind industry location are. Firstly, we construct regional specialisation and geographical concentration indices for Spanish 50 provinces and 30 industrial sectors in 1979, 1986 and 1992. Secondly, we carry out an econometric analysis of the determinants of geographical concentration of industries. Our main conclusion is that there is no evidence of increasing specialisation in Spain between 1979 and 1992 and that the most important determinant of Spain¿s economic geography is scale economies. Furthermore, traditional trade theory has no effects in explaining the pattern of industrial concentration