On the decay of turbulence in plane Couette flow

The decay of turbulent and laminar oblique bands in the lower transitional range of plane Couette flow is studied by means of direct numerical simulations of the Navier--Stokes equations. We consider systems that are extended enough for several bands to exist, thanks to mild wall-normal under-resolution considered as a consistent and well-validated modelling strategy. We point out a two-stage process involving the rupture of a band followed by a slow regression of the fragments left. Previous approaches to turbulence decay in wall-bounded flows making use of the chaotic transient paradigm are reinterpreted within a spatiotemporal perspective in terms of large deviations of an underlying stochastic process.Comment: ETC13 Conference Proceedings, 6 pages, 5 figure

Critical exponents of directed percolation measured in spatiotemporal intermittency

A new experimental system showing a transition to spatiotemporal intermittency is presented. It consists of a ring of hundred oscillating ferrofluidic spikes. Four of five of the measured critical exponents of the system agree with those obtained from a theoretical model of directed percolation.Comment: 7 pages, 12 figures, submitted to PR

Transition from the Couette-Taylor system to the plane Couette system

We discuss the flow between concentric rotating cylinders in the limit of large radii where the system approaches plane Couette flow. We discuss how in this limit the linear instability that leads to the formation of Taylor vortices is lost and how the character of the transition approaches that of planar shear flows. In particular, a parameter regime is identified where fractal distributions of life times and spatiotemporal intermittency occur. Experiments in this regime should allow to study the characteristics of shear flow turbulence in a closed flow geometry.Comment: 5 pages, 5 figure

Fluid intake patterns of children and adolescents: results of six Liq.In7 national cross-sectional surveys

Purpose: This study aimed to identify and characterize patterns of fluid intake in children and adolescents from six countries: Argentina, Brazil, China, Indonesia, Mexico and Uruguay. Methods: Data on fluid intake volume and type amongst children (4–9 years; N = 1400) and adolescents (10–17 years; N = 1781) were collected using the validated 7-day fluid-specific record (Liq.In7 record). To identify relatively distinct clusters of subjects based on eight fluid types (water, milk and its derivatives, hot beverages, sugar-sweetened beverages (SSB), 100% fruit juices, artificial/non-nutritive sweetened beverages, alcoholic beverages, other beverages), a cluster analysis (partitioning around k-medoids algorithm) was used. Clusters were then characterized according to their socio-demographics and lifestyle indicators. Results: The six interpretable clusters identified were: low drinkers–SSB (n 523), low drinkers–water and milk (n 615), medium mixed drinkers (n 914), high drinkers–SSB (n 513), high drinkers–water (n 352) and very high drinkers–water (n 264). Country of residence was the dominant characteristic, followed by socioeconomic level, in all six patterns. Conclusions: This analysis showed that consumption of water and SSB were the primary drivers of the clusters. In addition to country, socio-demographic and lifestyle factors played a role in determining the characteristics of each cluster. This information highlights the need to target interventions in particular populations aimed at changing fluid intake behavior and improving health in children and adolescents

Increasing water intake in pre-school children with unhealthy drinking habits: a year-long controlled longitudinal field experiment assessing the impact of information, water affordance, and social regulation

Objective We investigated the effect of three interventions to increase the plain water consumption of children with unhealthy drinking habits, with an innovative approach combining the three layers of Installation Theory: embodied competences, affordances and social regulation. Methods 334 preschool children and their carers were allocated to three interventions: Control (control): no intervention, Information (info): online coaching sessions on water health benefits aiming at modifying embodied competences (knowledge), Information + Water Affordance (info + w): the same plus home delivery of small bottles of water. After three months, half of the info and info + w subjects were allocated to Social Regulation (+social) (on-line discussion forum) or no further intervention (-social). Intake of plain water and all other fluid types of the children were recorded by the carers 6 times over a year using an online 7-day fluid-specific dietary record.Results Over 1 year, all groups significantly increased daily water consumption by 3.0–7.8 times (+118 to +222 mL). Info + w + social and Info-social generated the highest increase in plain water intake after one year compared to baseline, by 7.8 times (+216 mL) and 6.7 times (+222 mL) respectively; both significantly exceeded the control (3.0 times, +118 mL), whilst the effect of info + w-social (5.0 times, +158 mL) and info + social (5.3 times, +198 mL) did not differ from that of control. All groups saw a decrease of sweetened beverages intake, again with info + w + social generating the largest decrease (−27%; −172 mL). No changes in other fluids or total fluid intake were observed. Conclusions Sustainable increased water consumption can be achieved in children with unhealthy drinking habits by influencing representations, changing material affordances, and providing social regulation. Combining the three provided the strongest effect as predicted by Installation Theory

Deep neck infection complicating lymphadenitis caused by Streptococcus intermedius in an immunocompetent child

BACKGROUND: Streptococcus intermedius belongs to the Streptococcus anginosus group. It is part of the normal flora of the human mouth, but it can be etiologically associated with deep-site infections. CASE PRESENTATION: We present a case of deep neck infection complicating Streptococcus intermedius lymphadenitis, which developed in an immunocompetent 14-year-old boy with a history of recent dental work. The infection was ultimately eradicated by a combined medical and surgical approach. CONCLUSION: Our report suggests that combined medical and surgical therapy is essential for the complete resolution of deep infections caused by Streptococcus intermedius. Molecular biological techniques can be useful in guiding the diagnostic investigation and providing insight into the possibility of occult abscesses, which are particularly common with Streptococcus intermedius infections

Pyrolysis Gas Composition for a Phenolic Impregnated Carbon Ablator Heatshield

Published physical properties of phenolic impregnated carbon ablator (PICA) are compiled, and the composition of the pyrolysis gases that form at high temperatures internal to a heatshield is investigated. A link between the composition of the solid resin, and the composition of the pyrolysis gases created is provided. This link, combined with a detailed investigation into a reacting pyrolysis gas mixture, allows a consistent, and thorough description of many of the physical phenomena occurring in a PICA heatshield, and their implications, to be presented

Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO