Lagrangian analysis of fluid transport in empirical vortex ring flows

In this paper we apply dynamical systems analyses and computational tools to fluid transport in empirically measured vortex ring flows. Measurements of quasisteadily propagating vortex rings generated by a mechanical piston-cylinder apparatus reveal lobe dynamics during entrainment and detrainment that are consistent with previous theoretical and numerical studies. In addition, the vortex ring wake of a free-swimming Aurelia aurita jellyfish is measured and analyzed in the framework of dynamical systems to elucidate similar lobe dynamics in a naturally occurring biological flow. For the mechanically generated rings, a comparison of the net entrainment rate based on the present methods with a previous Eulerian analysis shows good correspondence. However, the current Lagrangian framework is more effective than previous analyses in capturing the transport geometry, especially when the flow becomes more unsteady, as in the case of the free-swimming jellyfish. Extensions of these results to more complex flow geometries is suggested

Towards an understanding of ESL students' approaches to learning: a study of conceptions of learning, perceptions of situational demands, learning approaches and learning outcomes

Includes bibliographical references.An hypothesised relationship between levels of proficiency in English of ESL (English as a Second Language) students and the approaches to learning which they adopt, in situations in which English is the language of instruction, is the focus of this study. An attempt was made to identify the extent to which students, who are required to learn in a second language, adopt undesirable approaches to learning as a consequence of linguistic or cultural factors. Such students appear to adopt reproductive strategies to pass examinations and retain only isolated pieces of information for practical application. In a sense, they graduate but remain unqualified. Quantitative responses of 307 students, relating to their contextualised perceptions of the demands of the learning situation, were gathered and analysed using a learning approach categorisation procedure. Qualitative responses of 120 students, relating to their descriptions of the context and content of learning, were gathered in semi-structured interviews to supplement and enrich the quantitive data collected. Levels of proficiency in the language of instruction were measured using integrative tests of comprehension of spoken discourse and written texts presented in actual lecture situations. Students were given the opportunity to rate the lectures and reading material from which they were expected to learn and self-esteem was measured as a construct considered likely to affect perceptions of the demands of the learning situation. Concurrently with the above, a group of students from each of 3 year groups was taught a new topic over a short series of lectures and tested for understanding in the language of instruction. Balanced groups, from each of the 3 year groups, were taught the same topic and tested for understanding in the mother-tongue. This procedure was subsequently replicated with a second topic of similar complexity, across all three year groups, with languages switched. Critical aspects of the teaching/learning situation were kept constant. These procedures provided compelling evidence, after analysis of quantitative and qualitative data, of a relationship between proficiency in the language of instruction and the ways in which students engage in learning tasks. Difficulty with the language of instruction appears to increase the demands of the learning situation and the likelihood of adopting reproducing strategies, which are not normally associated with success in terms of learning outcomes

Observation of a possible superflare on Proxima Centauri

We report the observation on UT 2017 July 1 of an unusually powerful flare detected in near-infrared continuum photometry of Proxima Centauri. During a campaign monitoring the star for possible exoplanet transits, we identified an increase in Sloan i' flux leading to an observed peak at BJD 2457935.996 that was at least 10 per cent over pre-flare flux in this band. It was followed by a two-component rapid decline in the first 100 s that became a slower exponential decay with time constant of 1350 s. A smaller flare event 1300 s after the first added an incremental peak flux increase of 1 per cent of pre-flare flux. Since the onset of the flare was not fully time resolved at a cadence of 62 s, its actual peak value is unknown but greater than the time average over a single exposure of 20 s. The i' band is representative of broad optical and near-IR continuum flux over which the integrated energy of the flare is 100 times the stellar luminosity. This meets the criteria that established the concept of superflares on similar stars. The resulting implied ultraviolet flux and space weather could have had an extreme effect on the atmospheres of planets within the star's otherwise habitable zone

Opiate substitution treatment combined with appropriate psychosocial interventions.

This paper outlines the benefits of several opiate agonists in reducing health risks and criminal behaviour. The paper focuses not only methadone programmes, but also the use of newer mu ophoid agonists such as levo-alpha-acetylmethadol (LAAM), which has been approved for use in American clinics. The paper cautions against take home doses of this opiate agonist due to its late onset of reaction, which could lead to overdose

Identification of Hemodynamically Optimal Coronary Stent Designs Based on Vessel Caliber

Coronary stent design influences local patterns of wall shear stress (WSS) that are associated with neointimal growth, restenosis, and the endothelialization of stent struts. The number of circumferentially repeating crowns NC for a given stent de- sign is often modified depending on the target vessel caliber, but the hemodynamic implications of altering NC have not previously been studied. In this investigation, we analyzed the relationship between vessel diameter and the hemodynamically optimal NC using a derivative-free optimization algorithm coupled with computational fluid dynamics. The algorithm computed the optimal vessel diameter, defined as minimizing the area of stent-induced low WSS, for various configurations (i.e., NC) of a generic slotted-tube design and designs that resemble commercially available stents. Stents were modeled in idealized coronary arteries with a vessel diameter that was allowed to vary between 2 and 5 mm. The results indicate that the optimal vessel diameter increases for stent configurations with greater NC, and the designs of current commercial stents incorporate a greater NC than hemodynamically optimal stent designs. This finding suggests that reducing the NC of current stents may improve the hemodynamic environment within stented arteries and reduce the likelihood of excessive neointimal growth and thrombus formation

Use of GFCF Diets in children with ASD. An investigation into parents' beliefs using the theory of planned behaviour

Gluten free/Casein free (GFCF) diets are one of the most common types of Complementary and Alternative Medicines (CAM) used in Autism Spectrum Disorders (ASD) despite little evidence to support positive effects. There has been no theory driven literature that has investigated parent's reasons for their use. The Theory of Planned Behaviour (TPB) was used to examine parent's intentions to use GFCF diets for their child with an ASD. Treatment and causal beliefs were also examined. Parents (n=33, children aged 3-17 years) were influenced by anticipated regret, positive outcomes and attitude. Future interventions should provide information to parents and health professionals about the possible causes of ASD and therapy options which are in line with current recommendations

Therapeutic Kitchens in Dementia Care Settings

Therapeutic kitchens, also referred to as country kitchen, domestic kitchens, or activity-based kitchens, have been cited as supportive spaces for residents with dementia. The purpose of this research is to identify physical features that are typically included in therapeutic kitchen design and to explore how these features support activities. Interviews and observation were conducted in the facilities with a therapeutic kitchen. A two-page questionnaire regarding therapeutic kitchens was distributed to 631 nursing homes and assisted living facilities throughout the United States. Results suggest that universal design principles, certain appliances and safety features, as well as homelike imagery, should be incorporated in therapeutic kitchen design.https://dc.uwm.edu/caupr_mono/1013/thumbnail.jp

Vlasov moments, integrable systems and singular solutions

The Vlasov equation for the collisionless evolution of the single-particle probability distribution function (PDF) is a well-known Lie-Poisson Hamiltonian system. Remarkably, the operation of taking the moments of the Vlasov PDF preserves the Lie-Poisson structure. The individual particle motions correspond to singular solutions of the Vlasov equation. The paper focuses on singular solutions of the problem of geodesic motion of the Vlasov moments. These singular solutions recover geodesic motion of the individual particles.Comment: 16 pages, no figures. Submitted to Phys. Lett.