3D wedge filling and 2D random-bond wetting

Fluids adsorbed in 3D wedges are shown to exhibit two types of continuous interfacial unbinding corresponding to critical and tricritical filling respectively. Analytic solution of an effective interfacial model based on the transfer-matrix formalism allows us to obtain the asymptotic probability distribution functions for the interfacial height when criticality and tricriticality are approached. Generalised random walk arguments show that, for systems with short-ranged forces, the critical singularities at these transitions are related to 2D complete and critical wetting with random bond disorder respectively.Comment: 7 pages, 3 figures, accepted for publication in Europhysics Letter

Correlation function algebra for inhomogeneous fluids

We consider variational (density functional) models of fluids confined in parallel-plate geometries (with walls situated in the planes z=0 and z=L respectively) and focus on the structure of the pair correlation function G(r_1,r_2). We show that for local variational models there exist two non-trivial identities relating both the transverse Fourier transform G(z_\mu, z_\nu;q) and the zeroth moment G_0(z_\mu,z_\nu) at different positions z_1, z_2 and z_3. These relations form an algebra which severely restricts the possible form of the function G_0(z_\mu,z_\nu). For the common situations in which the equilibrium one-body (magnetization/number density) profile m_0(z) exhibits an odd or even reflection symmetry in the z=L/2 plane the algebra simplifies considerably and is used to relate the correlation function to the finite-size excess free-energy \gamma(L). We rederive non-trivial scaling expressions for the finite-size contribution to the free-energy at bulk criticality and for systems where large scale interfacial fluctuations are present. Extensions to non-planar geometries are also considered.Comment: 15 pages, RevTex, 4 eps figures. To appear in J.Phys.Condens.Matte

Moving tales, exploring narrative strategies for scalable locative audio drama.

This paper reports on a recent collaboration between the Lansdown Centre for Electronic Arts at Middlesex University and the BBC Radio Drama Department, which was designed to investigate the narrative possibilities of locative media in a drama context. The locative drama Scratch is the first outcome of an ongoing research project, Locating Drama, whose aim is to investigate and develop narrative strategies that take full advantage of the current generation of GPS enabled portable computing devices for audio drama. In particular, we are exploring content and modes of interaction, which, while based on location awareness are not in any way site-specific allowing users to experience the drama in a location of their choice. We will refer to this approach as translocational as it allows the translation of locative media experiences to a wide variety of spaces. The translocational approach is of particular interest to broadcasters as it is more scalable than a site-specific paradigm, opening the possibility of downloadable location-aware podcasts featuring professionally authored content for a wide audience

A feasibility study of signed consent for the collection of patient identifiable information for a national paediatric clinical audit database

Objectives: To investigate the feasibility of obtaining signed consent for submission of patient identifiable data to a national clinical audit database and to identify factors influencing the consent process and its success. Design: Feasibility study. Setting: Seven paediatric intensive care units in England. Participants: Parents/guardians of patients, or patients aged 12-16 years old, approached consecutively over three months for signed consent for submission of patient identifiable data to the national clinical audit database the Paediatric Intensive Care Audit Network (PICANet). Main outcome measures: The numbers and proportions of admissions for which signed consent was given, refused, or not obtained (form not returned or form partially completed but not signed), by age, sex, level of deprivation, ethnicity (South Asian or not), paediatric index of mortality score, length of hospital stay (days in paediatric intensive care). Results: One unit did not start and one did not fully implement the protocol, so analysis excluded these two units. Consent was obtained for 182 of 422 admissions (43%) (range by unit 9% to 84%). Most (101/182; 55%) consents were taken by staff nurses. One refusal (0.2%) was received. Consent rates were significantly better for children who were more severely ill on admission and for hospital stays of six days or more, and significantly poorer for children aged 10-14 years. Long hospital stays and children aged 10-14 years remained significant in a stepwise regression model of the factors that were significant in the univariate model. Conclusion: Systematically obtaining individual signed consent for sharing patient identifiable information with an externally located clinical audit database is difficult. Obtaining such consent is unlikely to be successful unless additional resources are specifically allocated to training, staff time, and administrative support

Derivation of a Non-Local Interfacial Hamiltonian for Short-Ranged Wetting II: General Diagrammatic Structure

In our first paper, we showed how a non-local effective Hamiltionian for short-ranged wetting may be derived from an underlying Landau-Ginzburg-Wilson model. Here, we combine the Green's function method with standard perturbation theory to determine the general diagrammatic form of the binding potential functional beyond the double-parabola approximation for the Landau-Ginzburg-Wilson bulk potential. The main influence of cubic and quartic interactions is simply to alter the coefficients of the double parabola-like zig-zag diagrams and also to introduce curvature and tube-interaction corrections (also represented diagrammatically), which are of minor importance. Non-locality generates effective long-ranged many-body interfacial interactions due to the reflection of tube-like fluctuations from the wall. Alternative wall boundary conditions (with a surface field and enhancement) and the diagrammatic description of tricritical wetting are also discussed.Comment: (14 pages, 2 figures) Submitted J. Phys. Condens. Matte

Codeine misuse and dependence in South Africa – learning from substance abuse treatment admissions

Background. Misuse of prescription and over-the-counter codeine-containing products is a global public health issue.Objectives. To investigate the extent of treatment demand related to the misuse of codeine or codeine dependence in South Africa (SA) and the profile of patients seeking treatment, so as to understand the nature and extent of the problem.Method. Data were collected from centres participating in the South African Community Epidemiology Network on Drug Use in 2014. A total of 17 260 admissions were recorded.Results. There were 435 recorded treatment admissions for codeine misuse or dependence as a primary or secondary substance of abuse (2.5% of all admissions). Of treatment admissions, 137 (0.8%)  involved codeine as the primary substance of abuse; 74.9% of patients were males, with an even spread across population groups. Ages ranged from 11 to 70 years, with the highest proportion aged 20 - 29  years; >40% were referred by self, family and/or friends, and 26.7% by health professionals; and 36.8% had received treatment previously. The majority reported misuse of tablets/capsules, with 17.6% reporting misuse of syrups. Oral use comprised 96.6% and daily use 63.1%.Conclusions. Data from treatment admissions related to codeine misuse and dependence are  informative, but provide an incomplete picture of the nature and extent of codeine-related problems in SA. Other data sources must be considered before further regulatory/policy changes regarding codeine are implemented

Aboriginal children and family connections to primary health care whilst homeless and in high housing mobility: observations from a Nurse Practitioner-led service

Aim: This article documents the impact of a Nurse Practitioner-led primary health service for disadvantaged children living in housing instability or homelessness. It identifies that First Nations children miss out on essential primary care, particularly immunisation, but have less severe health conditions than non-First Nations children living in housing insecurity. Background: Health services for homeless populations focus on the 11% of rough sleepers, little is done for the 22% of children in Australia living in housing instability; many of whom are from First Nations families. Little is known of the health status of these children or their connections to appropriate primary health care. Methods: This research implemented an innovative model of extended health care delivery, embedding a Nurse Practitioner in a homeless service to work with families providing health assessments and referrals, using clinically validated assessment tools. This article reports on proof of concept findings on the service that measured immunisation rates, developmental, medical, dental and mental health needs of children, particularly First Nations children, using a three-point severity level scale with Level 3 being the most severe and in need of immediate referral to a specialist medical service. Findings: Forty-three children were referred by the service to the Nurse Practitioner over a 6-month period, with nine identifying as First Nations children. Differences in severity levels between First Nations/non-First Nations children were Level 1, First Nations/non-First Nations 0/15%; Level 2, 10/17%; and Level 3, 45/29%. Forty-five percent of First Nations children had no health problems, as compared to 29% on non-First Nations children. Immunisation rates were low for both cohorts. No First Nations child was immunised and only 9% of the non-First Nations children. While numbers for both cohorts are too low for valid statistical analysis, the lower levels of severity for First Nations children suggest stronger extended family support and the positive impact of cultural norms of reciprocity

Fractal scan strategies for selective laser melting of ‘unweldable’ nickel superalloys

The high thermal gradients experienced during manufacture via selective laser melting commonly result in cracking of high γ/γ′ Nickel based superalloys. Such defects cannot be tolerated in applications where component integrity is of paramount importance. To overcome this, many industrial practitioners make use of hot isostatic pressing to ‘heal’ these defects. The possibility of such defects re-opening during the component life necessitates optimisation of SLM processing parameters in order to produce the highest bulk density and integrity in the as-built state. In this paper, novel fractal scanning strategies based upon mathematical fill curves, namely the Hilbert and Peano-Gosper curve, are explored in which the use of short vector length scans, in the order of 100 μm, is used as a method of reducing residual stresses. The effect on cracking observed in CM247LC superalloy samples was analysed using image processing, comparing the novel fractal scan strategies to more conventional ‘island’ scans. Scanning electron microscopy and energy dispersive X-ray spectroscopy was utilised to determine the cracking mechanisms. Results show that cracking occurs via two mechanisms, solidification and liquation, with a strong dependence on the laser scan vectors. Through the use of fractal scan strategies, bulk density can be increased by 2 ± 0.7% when compared to the ‘island’ scanning, demonstrating the potential of fractal scan strategies in the manufacture of typically ‘unweldable’ nickel superalloys