Thermal convection in fluidized granular systems

Thermal convection is observed in molecular dynamic simulation of a fluidized granular system of nearly elastic hard disks moving under gravity, inside a rectangular box. Boundaries introduce no shearing or time dependence, but the energy injection comes from a slip (shear-free) thermalizing base. The top wall is perfectly elastic and lateral boundaries are either elastic or periodic. The observed convection comes from the effect of gravity and the spontaneous granular temperature gradient that the system dynamically develops.Comment: 4 pages, 5 figure

Alfvén waves in the near-PSBL lobe: Cluster observations

Electromagnetic low-frequency waves in the magnetotail lobe close to the PSBL (Plasma Sheet Boundary Layer) are studied using the Cluster spacecraft. The lobe waves show Alfvénic properties and transport their wave energy (Poynting flux) on average toward the Earth along magnetic field lines. Most of the wave events are rich with oxygen (O+) ion plasma. The rich O+ plasma can serve to enhance the magnetic field fluctuations, resulting in a greater likelihood of observation, but it does not appear to be necessary for the generation of the waves. Taking into account the fact that all events are associated with auroral electrojet enhancements, the source of the lobe waves might be a substorm-associated instability, i.e. some instability near the reconnection site, or an ion beam-related instability in the PSBL

An Exploration of the Patient Lived Experience of Remission and Relapse of Type 2 Diabetes Following Bariatric Surgery

BACKGROUND: Bariatric surgery is the most effective treatment for patients with obesity and type 2 diabetes (T2DM), inducing profound metabolic changes associated with improvements in glycaemic control. In spite of the recognition of the physiological changes associated with bariatric surgery, what remains underappreciated is the patient experience of surgery to treat T2DM. OBJECTIVES: This study explored the patient experience with regard to motivations, expectations and outcomes, including remission and relapse of diabetes. METHODS: An in-depth qualitative approach was adopted, encompassing semi-structured interviews with patients (n=17) living with obesity and T2DM both pre- and postsurgery. Interpretive thematic analysis identified emergent themes using a grounded approach. RESULTS: Analysis revealed a number of themes throughout the interviews which included motivations and perceived benefits of surgery, obesity stigma and its impact on self-worth as well as perceptions of remission or relapse and the implications for sense of control. CONCLUSIONS: The motivation for undergoing bariatric surgery was driven by health concerns, namely T2DM and the desire to reduce the risk of developing diabetes-related complications. Patients highlighted social and self-stigmatisation associated with obesity and T2DM, leading to feelings of shame and an inability to seek support from family or healthcare professionals. Stigmatisation created a sense of failure and feeling of guilt for having T2DM. As a result, patients felt responsible for maintaining disease remission postoperatively and regarded the need for medication as a sign of treatment failure

A model for collisions in granular gases

We propose a model for collisions between particles of a granular material and calculate the restitution coefficients for the normal and tangential motion as functions of the impact velocity from considerations of dissipative viscoelastic collisions. Existing models of impact with dissipation as well as the classical Hertz impact theory are included in the present model as special cases. We find that the type of collision (smooth, reflecting or sticky) is determined by the impact velocity and by the surface properties of the colliding grains. We observe a rather nontrivial dependence of the tangential restitution coefficient on the impact velocity.Comment: 11 pages, 2 figure

Adopting a healthy lifestyle when pregnant and obese - an interview study three years after childbirth

Background: Obesity during pregnancy is increasing and is related to life-threatening and ill-health conditions in both mother and child. Initiating and maintaining a healthy lifestyle when pregnant with body mass index (BMI) ≥ 30 kg/m2 can improve health and decrease risks during pregnancy and of long-term illness for the mother and the child. To minimise gestational weight gain women with BMI ≥ 30 kg/m2 in early pregnancy were invited to a lifestyle intervention including advice and support on diet and physical activity in Gothenburg, Sweden. The aim of this study was to explore the experiences of women with BMI ≥ 30 kg/m2 regarding minimising their gestational weight gain, and to assess how health professionals' care approaches are reflected in the women's narratives. Methods: Semi-structured interviews were conducted with 17 women who had participated in a lifestyle intervention for women with BMI ≥ 30 kg/m2 during pregnancy 3 years earlier. The interviews were digitally recorded and transcribed in full. Thematic analysis was used. Results: The meaning of changing lifestyle for minimising weight gain and of the professional's care approaches is described in four themes: the child as the main motivation for making healthy changes; a need to be seen and supported on own terms to establish healthy routines; being able to manage healthy activities and own weight; and need for additional support to maintain a healthy lifestyle. Conclusions: To support women with BMI ≥ 30 kg/m2 to make healthy lifestyle changes and limit weight gain during pregnancy antenatal health care providers should 1) address women's weight in a non-judgmental way using BMI, and provide accurate and appropriate information about the benefits of limited gestational weight gain; 2) support the woman on her own terms in a collaborative relationship with the midwife; 3) work in partnership to give the woman the tools to self-manage healthy activities and 4) give continued personal support and monitoring to maintain healthy eating and regular physical activity habits after childbirth involving also the partner and family

Public health campaigns and obesity - a critique

<p>Abstract</p> <p>Background</p> <p>Controlling obesity has become one of the highest priorities for public health practitioners in developed countries. In the absence of safe, effective and widely accessible high-risk approaches (e.g. drugs and surgery) attention has focussed on community-based approaches and social marketing campaigns as the most appropriate form of intervention. However there is limited evidence in support of substantial effectiveness of such interventions.</p> <p>Discussion</p> <p>To date there is little evidence that community-based interventions and social marketing campaigns specifically targeting obesity provide substantial or lasting benefit. Concerns have been raised about potential negative effects created by a focus of these interventions on body shape and size, and of the associated media targeting of obesity.</p> <p>Summary</p> <p>A more appropriate strategy would be to enact high-level policy and legislative changes to alter the obesogenic environments in which we live by providing incentives for healthy eating and increased levels of physical activity. Research is also needed to improve treatments available for individuals already obese.</p

‘Do i care?’ young adults' recalled experiences of early adolescent overweight and obesity: a qualitative study

&lt;p&gt;Objective: Individual behaviour change to reduce obesity requires awareness of, and concern about, weight. This paper therefore describes how young adults, known to have been overweight or obese during early adolescence, recalled early adolescent weight-related awareness and concerns. Associations between recalled concerns and weight-, health- and peer-related survey responses collected during adolescence are also examined.&lt;/p&gt; &lt;p&gt;Design: Qualitative semi-structured interviews with young adults; data compared with responses to self-report questionnaires obtained in adolescence.&lt;/p&gt; &lt;p&gt;Participants: A total of 35 participants, purposively sub-sampled at age 24 from a longitudinal study of a school year cohort, previously surveyed at ages 11, 13 and 15. Physical measures during previous surveys allowed identification of participants with a body mass index (BMI) indicative of overweight or obesity (based on British 1990 growth reference) during early adolescence. Overall, 26 had been obese, of whom 11 had BMI99.6th centile, whereas 9 had been overweight (BMI=95th–97.9th centile).&lt;/p&gt; &lt;p&gt;Measures: Qualitative interview responses describing teenage life, with prompts for school-, social- and health-related concerns. Early adolescent self-report questionnaire data on weight-worries, self-esteem, friends and victimisation (closed questions).&lt;/p&gt; &lt;p&gt;Results: Most, but not all recalled having been aware of their overweight. None referred to themselves as having been obese. None recalled weight-related health worries. Recollection of early adolescent obesity varied from major concerns impacting on much of an individual's life to almost no concern, with little relation to actual severity of overweight. Recalled concerns were not clearly patterned by gender, but young adult males recalling concerns had previously reported more worries about weight, lower self-esteem, fewer friends and more victimisation in early adolescence; no such pattern was seen among females. Conclusion: The popular image of the unhappy overweight teenager was not borne out. Many obese adolescents, although well aware of their overweight recalled neither major dissatisfaction nor concern. Weight-reduction behaviours are unlikely in such circumstances.&lt;/p&gt

Ising model on 3D random lattices: A Monte Carlo study

We report single-cluster Monte Carlo simulations of the Ising model on three-dimensional Poissonian random lattices with up to 128,000 approx. 503 sites which are linked together according to the Voronoi/Delaunay prescription. For each lattice size quenched averages are performed over 96 realizations. By using reweighting techniques and finite-size scaling analyses we investigate the critical properties of the model in the close vicinity of the phase transition point. Our random lattice data provide strong evidence that, for the available system sizes, the resulting effective critical exponents are indistinguishable from recent high-precision estimates obtained in Monte Carlo studies of the Ising model and \phi^4 field theory on three-dimensional regular cubic lattices.Comment: 35 pages, LaTex, 8 tables, 8 postscript figure