An investigation of the accuracy of finite difference methods in the solution of linear elasticity problems

The accuracy of the finite difference method in the solution of linear elasticity problems that involve either a stress discontinuity or a stress singularity is considered. Solutions to three elasticity problems are discussed in detail: a semi-infinite plane subjected to a uniform load over a portion of its boundary; a bimetallic plate under uniform tensile stress; and a long, midplane symmetric, fiber reinforced laminate subjected to uniform axial strain. Finite difference solutions to the three problems are compared with finite element solutions to corresponding problems. For the first problem a comparison with the exact solution is also made. The finite difference formulations for the three problems are based on second order finite difference formulas that provide for variable spacings in two perpendicular directions. Forward and backward difference formulas are used near boundaries where their use eliminates the need for fictitious grid points

Provision of smoking cessation support for pregnant women in England: results from an online survey of NHS Stop Smoking Services for Pregnant women

Background: Smoking during pregnancy is a major public health concern and an NHS priority. In 2010, 26% of UK women smoked immediately before or during their pregnancy and 12% smoked continuously. Smoking cessation support is provided through free at the point of use Stop Smoking Services for Pregnant women (SSSP). However, to date, little is known of how these services provide support across England. The aim of this study was to describe the key elements of support provided through English SSSP. Methods: SSSP managers were invited to participate in this survey by email. Data were then collected via an online questionnaire; one survey was completed for each SSSP. Up to four reminder emails were sent over a two month period. Results: 86% (121 of 141) of services completed the survey. Responding services were, on average, larger than non-responding services in terms of the number of pregnant women setting quit dates and successfully quitting (p < 0.01). In line with the 2010 NICE guidelines, Stop Smoking in Pregnancy and following Childbirth, one in five SSSP identified pregnant smokers using carbon monoxide (CO) testing and refer via an opt-out pathway. All services offered nicotine replacement therapy (NRT) to pregnant women and 87% of services also offered dual therapy NRT, i.e. combination of a patch and short acting NRT product.. The 2010 NICE guidelines note that services should be flexible and client-centred. Consistent with this, SSSP offer pregnant women a range of support types (median 4) including couple/family, group (open or closed) or one-to-one. These are available in a number of locations (median 5), including in community venues, clinics and women's homes. Conclusions: English Stop Smoking Services offer behavioural support and pharmacotherapy to pregnant women motivated to quit smoking. Interventions provided are generally evidence-based and delivered in a variety of both social and health care settings

Delivery of alcohol brief interventions in community-based youth work settings:exploring feasibility and acceptability in a qualitative study

Background  Alcohol Brief Interventions (ABIs) are increasingly being delivered in community-based youth work settings. However, little attention has been paid to how they are being implemented in such settings, or to their feasibility and acceptability for practitioners or young people. The aim of this qualitative study was to explore the context, feasibility and acceptability of ABI delivery in youth work projects across Scotland.  Methods  Individual, paired and group interviews were conducted with practitioners and young people in nine community projects that were either involved in the delivery of ABIs or were considering doing so in the near future. A thematic analysis approach was used to analyse data.  Results  ABIs were delivered in a diverse range of youth work settings including the side of football pitches, on the streets as part of outreach activities, and in sexual health drop-in centres for young people. ABI delivery differed in a number of important ways from delivery in other health settings such as primary care, particularly in being largely opportunistic and flexible in nature. ABIs were adapted by staff in line with the ethos of their project and their own roles, and to avoid jeopardising their relationships with young people. Young people reacted positively to the idea of having conversations about alcohol with youth project workers, but confirmed practitioners’ views about the importance of these conversations taking place in the context of an existing trusting relationship.  Conclusion  ABIs were feasible in a range of youth work settings with some adaptation. Acceptability to staff was strongly influenced by perceived benefits, and the extent to which ABIs fitted with their project’s ethos. Young people were largely comfortable with such conversations. Future implementation efforts should be based on detailed consideration of current practice and contexts. Flexible models of delivery, where professional judgement can be exercised over defined but adaptable content, may be better appreciated by staff and encourage further development of ABI activity

N. AKKAS Buckling and Postbuckling Behavior of Clamped Shallow Spherical Shells Under Axisymmetric Ring Loads

This paper presents the results of a numerical study of the buckling and initial postbuckling behavior of clamped shallow spherical shells under axisymmetric ring loads. This behavior is studied for a cap with fixed geometry when the location of the ring load is allowed to vary from the equivalent of a concentrated load at the apex to a location near the midpoint of the shell base radius, and for a fixed ring load location when the shell geometry is allowed to vary. It is found in both studies that a significant range of the geometric shell parameter X exists such that buckling is accompanied by a loss in loadcarrying capacity