Nonlinear Programming Techniques Applied to Stochastic Programs with Recourse

Stochastic convex programs with recourse can equivalently be formulated as nonlinear convex programming problems. These possess some rather marked characteristics. Firstly, the proportion of linear to nonlinear variables is often large and leads to a natural partition of the constraints and objective. Secondly, the objective function corresponding to the nonlinear variables can vary over a wide range of possibilities; under appropriate assumptions about the underlying stochastic program it could be, for example, a smooth function, a separable polyhedral function or a nonsmooth function whose values and gradients are very expensive to compute. Thirdly, the problems are often large-scale and linearly constrained with special structure in the constraints. This paper is a comprehensive study of solution methods for stochastic programs with recourse viewed from the above standpoint. We describe a number of promising algorithmic approaches that are derived from methods of nonlinear programming. The discussion is a fairly general one, but the solution of two classes of stochastic programs with recourse are of particular interest. The first corresponds to stochastic linear programs with simple recourse and stochastic right-hand-side elements with given discrete probability distribution. The second corresponds to stochastic linear programs with complete recourse and stochastic right-hand-side vectors defined by a limited number of scenarios, each with given probability. A repeated theme is the use of the MINOS code of Murtagh and Saunders as a basis for developing suitable implementations

Algorithms for Stochastic Programs: The Case for Nonstochastic Tenders

We consider solution strategies for stochastic programs whose deterministic equivalent programs take on one specific form. We suggest algorithms based upon (i) extensions of the revised simplex method, (ii) inner approximations (generalized programming techniques), (iii) outer approximations (min-max strategies). We briefly discuss implementation and associated software considerations

Primary care morbidity in Eastern Cape Province

Background. Primary health care in rural South Africa is predominantly provided by remote clinics and health centres. In 1994, health centres were upgraded and new health centres developed to serve as a health care filter between community clinics and district hospitals.Aim. To describe the spectrum of clinical problems encountered at a new health centre in an area of high economic deprivation and compare this with an adjacent community clinic and district hospital.Design. Cross-sectional survey.Setting. A rural clinic, health centre and district hospital in Eastern Cape Province, South Africa.Methods. The International Classification of Primary Care-2(ICPC-2) was used to code data collected over a 13-week period from patients presenting at a community clinic, health centre and district hospital.Results. Altogether, 4 383 patient encounters were recorded across all three sites. Most contacts at the clinic (97%) and the health centre (80%) were with a nurse. Females over 15 years of age comprised over half of all contacts at health facilities (53%). The most common diagnosis category was respiratory (23%). Cough was the most common symptom.Thirty per cent of children up to 5 years of age were seen for immunisations. Most childhood immunisations (79%) werecarried out at the health centre.Conclusion. Of all the health care facilities surveyed, the health centre had the highest throughput of patients, indicating that the health centre is an efficient filter between the community and hospital. The ICPC-2 can be successfully used to monitor encounters at similar African health care facilities.S Afr Med J 2010; 100: 309-312

A brief intervention for weight control based on habit-formation theory delivered through primary care: results from a randomised controlled trial

Background: Primary care is the 'first port of call' for weight control advice, creating a need for simple, effective interventions that can be delivered without specialist skills. Ten Top Tips (10TT) is a leaflet based on habit-formation theory that could fill this gap. The aim of the current study was to test the hypothesis that 10TT can achieve significantly greater weight loss over 3 months than ‘usual care’. Methods: A two-arm, individually randomised, controlled trial in primary care. Adults with obesity were identified from 14 primary care providers across England. Patients were randomised to either 10TT or 'usual care' and followed up at 3, 6, 12, 18 and 24 months. The primary outcome was weight loss at 3 months, assessed by a health professional blinded to group allocation. Difference between arms was assessed using a mixed-effect linear model taking into account the health professionals delivering 10TT, and adjusted for baseline weight. Secondary outcomes included body mass index, waist circumference, the number achieving a 5% weight reduction, clinical markers for potential comorbidities, weight loss over 24 months and basic costs. Results: Five-hundred and thirty-seven participants were randomised to 10TT (n=267) or to ‘usual care' (n=270). Data were available for 389 (72%) participants at 3 months and for 312 (58%) at 24 months. Participants receiving 10TT lost significantly more weight over 3 months than those receiving usual care (mean difference =−0.87kg; 95% confidence interval: −1.47 to −0.27; P=0.004). At 24 months, the 10TT group had maintained their weight loss, but the ‘usual care’ group had lost a similar amount. The basic cost of 10TT was low, that is, around £23 ($32) per participant. Conclusions: The 10TT leaflet delivered through primary care is effective in the short-term and a low-cost option over the longer term. It is the first habit-based intervention to be used in a health service setting and offers a low-intensity alternative to ‘usual care’

Improvement of brinjals (Solanum Melongena, L.) by selection in the Bombay province

This article does not have an abstract

Predicting the onset and persistence of episodes of depression in primary health care. The predictD-Spain study: Methodology

Background: The effects of putative risk factors on the onset and/or persistence of depression remain unclear. We aim to develop comprehensive models to predict the onset and persistence of episodes of depression in primary care. Here we explain the general methodology of the predictD-Spain study and evaluate the reliability of the questionnaires used. Methods: This is a prospective cohort study. A systematic random sample of general practice attendees aged 18 to 75 has been recruited in seven Spanish provinces. Depression is being measured with the CIDI at baseline, and at 6, 12, 24 and 36 months. A set of individual, environmental, genetic, professional and organizational risk factors are to be assessed at each follow-up point. In a separate reliability study, a proportional random sample of 401 participants completed the test-retest (251 researcher-administered and 150 self-administered) between October 2005 and February 2006. We have also checked 118,398 items for data entry from a random sample of 480 patients stratified by province. Results: All items and questionnaires had good test-retest reliability for both methods of administration, except for the use of recreational drugs over the previous six months. Cronbach's alphas were good and their factorial analyses coherent for the three scales evaluated (social support from family and friends, dissatisfaction with paid work, and dissatisfaction with unpaid work). There were 191 (0.16%) data entry errors. Conclusion: The items and questionnaires were reliable and data quality control was excellent. When we eventually obtain our risk index for the onset and persistence of depression, we will be able to determine the individual risk of each patient evaluated in primary health car

Context, mechanisms and outcomes in end-of-life care for people with advanced dementia: family carers perspective

Background: Keeping people living with advanced dementia in their usual place of residence is becoming a key governmental goal but to achieve this, family carers and health care professionals must negotiate how to provide optimal care. Previously, we reported a realist analysis of the health care professional perspective. Here, we report on family carer perspectives. We aimed to understand the similarities and differences between the two perspectives, gain insights into how the interdependent roles of family carers and HCPs can be optimised, and make recommendations for policy and practice. Method: Qualitative study using a realist approach in which we used the criteria from guidance on optimal palliative care in advanced dementia to examine key contexts, mechanisms and outcomes highlighted by family carers. Results: The themes and views of family caregivers resonate with those of health care professionals. Their overlapping anxieties related to business-driven care homes, uncertainty of families when making EOL decisions and the importance of symptom management referring to contexts, mechanisms and outcomes, respectively. Contexts specific to family carers were ad hoc information about services, dementia progression and access to funding. Not all family carers identified dementia as terminal, but many recognised the importance of continuity of care and knowing the wishes of the person with dementia. New mechanisms included specific resources for improving EOL care and barriers to discussing and planning for future care. Family carers identified the importance of comfort, being present, the meeting of basic care needs and feeling the right decisions have been made as good outcomes of care. Conclusions: Family carers and health care professionals share similar concerns about the challenges to good EOL dementia care. Better understanding of the effects of dementia at the advanced stages would improve confidence in EOL care and reduce uncertainty in decision making for family carers and health care professionals

Arthralgia in South Indian patients with pulmonary tuberculosis during treatment with pyrazinamide and rifampicin

Arthralgia was the major adverse reaction encountered in a clinical trial of the treatment of pulmonary tuberculosis with three short-course regimens containing pyrazinamide in South Indian patients. The first regimen was of rifampicin, streptomycin, isoniazid and pyrazinamide given daily for three months; the second was of the same four drugs daily for three months followed by streptomycin, isoniazid and pyrazinamide twice-weekly for two months, and the third was the same as the second except that rifampicin was not administered. Arthralgia was reported in 36% of 353 rifampicin patients and 66% of 179 non-rifampicin patients, a highly significant difference (p<0.001). The onset of arthralgia was mostly during the first two months of chemotherapy. The knees were affected in about 90% followed by the ankles in about 50% of the patients with arthralgia, and about 60% of these patients had one or more of the signs, swelling, tenderness and limitation of joint movement. Chemotherapy was modified in 10 rifampicin and 15 non-rifampicin patients; the rest of the patients were managed with symptomatic treatment with analgesics. There was a two to three fold increase in serum uric acid concentrations by the end of the first month and the concentrations were more or less stationary throughout the rest of the daily phase of treatment. The mean concentration during the daily phase of treatment in patients with arthralgia (0.482 mmoles/litre) was similar to that in those without arthralgia (0.484 mmoles/litre), while that in the rifampicin patients (0.476 mmoles/litre) was significantly lower (p=0.03) than that in the non-rifampicin patients (0.495 mmoles/litre)