Model for coiling and meandering instability of viscous threads

A numerical model is presented to describe both the transient and steady-state dynamics of viscous threads falling onto a plane. The steady-state coiling frequency w is calculated as a function of fall height H. In the case of weak gravity, w ~ H^{-1} and w ~ H are obtained for lower and higher fall heights respectively. When the effect of gravity is significant, the relation w ~ H^2 is observed. These results agree with the scaling laws previously predicted. The critical Reynolds number for coil-uncoil transition is discussed. When the gravity is weak, the transition occurs with hysteresis effects. If the plane moves horizontally at a constant speed, a variety of meandering oscillation modes can be observed experimentally. The present model also can describe this phenomenon. The numerically obtained state diagram for the meandering modes qualitatively agrees with the experiment.Comment: 12 pages, 10 figure

An interpretive investigation of perinatal HIV transmission : from the population to the personal

University of Technology, Sydney. Faculty of Nursing, Midwifery and Health.While there have been many studies investigating perinatal HIV infection, few have addressed the complexity of the disease. The complexities of HIV infection are compounded for families affected by the disease where several family members are infected. HIV infection is a particularly challenging disease when it affects children and their families as it has the potential to extinguish whole families, placing an infected family under extreme stress. The multigenerational impact of the disease, where several family members are infected and where multiple losses may have occurred as a result, severely affects the family’s ability to cope with existing problems. This dissertation explores the experience of children with perinatal HIV and their carers using an interpretative methodology to synthesise understandings from three separate epidemiological, case study, and interview studies. A review of data from the National Perinatal HIV Register provides information on perinatal transmission of HIV in Australia; a case study demonstrates the medical complexity of the disease from diagnosis to treatment while interviews with parents and children provide insight into the effects of the disease. The study is predicated not only on the research undertaken for this study but also on clinical experience of the researcher. The findings demonstrated that although HIV is a relatively rare disease in Australia transmission continues despite strategies which have demonstrated efficacy in preventing transmission from mother to child. Perinatal transmission continues to occur especially when women give birth before a diagnosis is made. The experiences of parents caring for children with HIV infection, although varied, demonstrate the complex nature of HIV. Once diagnosed with HIV, parents find themselves undertaking a fine balancing act during which they must negotiate to strike the right equilibrium for their family to endure the circumstances as best they can. They are faced with contradictory decisions in which, for example, they must disclose their HIV status to others to receive the support necessary to survive the emotional turmoil created by the disease. Children’s experiences of living with perinatal HIV infection are an ongoing process. Most of the children who were interviewed for this study had been affected by HIV either through severe ill health or by the death of one or both parents. Thus, for all the children, HIV was a very real entity even though at the present time all were now well and attending school full time. Across all major themes is the cumulative effect of HIV disease on the child and family. It is the cumulative effects of HIV that presents the greatest challenge for families and clinicians and it is this challenge that underpins the study. This study represents the beginning of a systematic approach to an examination of how and why Australian children have been infected through mother to child transmission and explores the perceptions and experiences of children and their families. It is hoped that this research will provide health care providers, managers and researchers an understanding with which to guide the care of children and their families living with perinatal HIV

Lower levels of damaged protein biomarkers in the plasma of overweight type 2 diabetic men following supplementation with a standardised bilberry extract

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Error analysis of collocation methods for the numerical solution of ordinary differential equations

PhD ThesisThis thesis is concerned with an error analysis of numerical methods for two point boundary value problems and much of the investigation is concentrated on collocation methods from an 'a posteriori' point of view. Most of the previous work on error bounds for boundary value problems has been of an 'a priori' nature, requiring knowledge of the inverse of the differential operator under consideration and furnishing convergence proofs and theoretical bounds on the error. There are however a few results of the converse nature and in this thesis means of determining error bounds in practice are developed, much of the analysis also applying to Fredholm integral equations of the second kind. In more detail, having firstly considered certain preliminaries the setting for the theory and the principal results for later use are presented. It is demonstrated how the approximate solution by collocation of linear differential equations fits into this background and different 'a priori' approaches are examined by example and shown to be rather unsatisfactory. The 'a posteriori' outlook is then considered and to achieve practical results the inverse of the approxi- mating operator is related to the inverse of the collocation matrix. However the problem of obtaining a suitable bound on the norm of this inverse operator is encountered and after examination of the most obvious approach which proves unsatisfactory a convenient bound is developed. Certain interesting computational properties of matrices involved in the process are discussed and a brief examination of condition numbers is given. A different theoretical analysis using the concept of a 'collectively compact sequence of operators' is considered and it is demonstrated that the approximate solution by collocation of linear differential equations can be 'extended' to satisfy the conditions for this theory. Again the error bounds are reduced to a more practical level and subsequently a generalisation of the notion of this extension is suggested. The implementation of the various practical error bounds which have been deduced is then considered in detail and formulae for their evaluation are presented. The numerical results of examples of this application are then given followed by a discussion of certain relevent points concerning the experiments. In the final chapter certain possible extensions of the analysis herein are briefly examined and lastly a review of the work of this thesis with appropriate conclusions is given

Transition in housing design and thermal comfort in rural Tanzania

This study evaluates the performance of three low-income passive housing designs at providing thermal comfort for their inhabitants in temperate tropical rural Tanzania. Severe climatic conditions in these upland regions include large daily oscillations in air temperature (14°C-36°C) and high levels of solar radiation, causing overheating which affects inhabitant health and wellbeing. Inadequate shelter in these difficult climatic conditions is a widespread problem with 71% of Tanzanians living in rural areas, of which 28% of are below the national poverty line. Over the last 10 years an increasing number of houses are using modern building materials (brick or concrete walls and iron roof) rather than traditional vernacular design (mud-pole walls and thatch roof). Three designs were chosen to describe this transition. The performances of the three houses were simulated across a study year using IES and then compared against five chosen criteria to assess thermal comfort. Detailed analyses of critical times of day and specific areas of the building envelope were used to identify critical areas of design. The traditional house overheated significantly less often with smaller diurnal indoor temperature swings than the modern houses (due to its higher roof insulation and wall thermal mass). It also experienced uncomfortably low temperatures least often but maintained higher temperatures for longer during hot evenings. The modern houses outperformed the traditional house in ventilation gains with constant heat rejection throughout the day and night. The traditional house’s open structure resulted in high daytime ventilation gains and night-time heat rejection. Consideration of the position and internal gains of each room was found to be an important design factor. Across the study year the traditional design provided greater thermal comfort. However, as durability and social pressures are important factors in the choice of building materials, the design of modern materials that can mimic and improve on traditional material performance is critical to improving the health of inhabitants

Cohort profile: the DASH (determinants of adolescent social well-being and health) study, an ethnically diverse cohort

No abstract available

Cervical cancer prevention in transgender men : a review

Funding MA was supported by the Horizon 2020 Framework Programme for Research and Innovation of the European Commission, through the RISCC Network (grant no.847845)Peer reviewedPostprin