Once-through steam generator (OTSG) materials and water chemistry. [PWR]

Materials and water chemistry research results associated with the development of the Oconee-1 Reactor steam generator are presented. A summary of water chemistry data acquired during preoperational testing and power operation to date is also included. These data confirm the operational practicality of the nuclear once-through concept using volatile water treatment and high purity condensate demineralized feedwater

Updating stochastic networks to integrate cross-sectional and longitudinal studies

Clinical trials are typically conducted over a population within a defined time period in order to illuminate certain characteristics of a health issue or disease process. These cross-sectional studies provide a snapshot of these disease processes over a large number of people but do not allow us to model the temporal nature of disease, which is essential for modelling detailed prognostic predictions. Longitudinal studies on the other hand, are used to explore how these processes develop over time in a number of people but can be expensive and time-consuming, and many studies only cover a relatively small window within the disease process. This paper explores the application of intelligent data analysis techniques for building reliable models of disease progression from both cross-sectional and longitudinal studies. The aim is to learn disease ‘trajectories’ from cross-sectional data by building realistic trajectories from healthy patients to those with advanced disease. We focus on exploring whether we can ‘calibrate’ models learnt from these trajectories with real longitudinal data using Baum-Welch re-estimation

Power analysis and sample size estimation

Determining appropriate sample size is often a difficult decision in the process of developing quantitative research proposals. The novice researcher may well understand that the need for an adequate sample size is an important issue, but lack the knowledge to make an informed decision. Often the sample size will be based on the constraints of practical considerations, such as time or cost, but with little confidence that the sample is adequate in any statistical sense. This paper explores power analysis as an approach to sample size estimation that can be used even by novice researchers to provide a more rational basis for such decisions. The principles underpinning power analysis and the factors that contribute to statistical power are discussed, with an example of power analysis applied to a simple experimental design. Some arguments against a perceived over-emphasis on power analysis are raised. Finally, relevant literature, computer software and World Wide Web resources are included (see Bibliography page 139)

Lifetime body mass index, other anthropometric measures of obesity and risk of knee or hip osteoarthritis in the GOAL case-control study

Objective: To examine the risk of large joint osteoarthritis (OA) in those becoming overweight during early adult life, and to assess the risks associated with high body mass index (BMI) and other anthropometric measures of obesity. Methods: BMI, waist and hip circumference were measured in the GOAL case-control study comprising hip OA cases (n = 1007), knee OA cases (n = 1042) and asymptomatic controls (n = 1121). Retrospective estimates of lifetime weight, body shape and other risk factors were collected using an interview-lead questionnaire. Odds ratios (ORs), adjusted OR (aOR), 95% confidence intervals (Os) and P values were calculated using logistic regression analysis. Results: BMI was associated with knee OA (aOR 2.68, 95% CI 2.33-3.09, P-trend <0.001) and hip OA (aOR 1.65, 95% CI 1.46-1.87, P-trend <0.001). Those who became overweight earlier in adulthood showed higher risks of lower limb OA (P-trend < 0.001 for knee OA and hip OA). Self-reported body shape was also associated with knee OA and hip OA, following a similar pattern to current and life-course BMI measures. Waist:hip ratio (WHR) at time of examination did not associate with OA independently of BMI, except in women-only analysis. Waist circumference was associated with lower limb OA risk. Conclusions: Becoming overweight earlier in adult life increased the risks of knee OA and hip OA. Different distribution patterns of adiposity may be related to OA risk in women. (C) 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved

Assessment of chloroquine single dose treatment of malaria due to Plasmodium vivax in Brazilian Amazon Cloroquina em dose simples no tratamento da malária por Plasmodium vivax na Amazônia brasileira

Malaria regions of the Amazon basin have been characterized by difficult access and non-compliance of the patients to treatment. In an attempt to assess the schizonticide efficacy of chloroquine in a single dose of 600 mg, the authors realized a double-blind, placebo-controlled trial in 132 outpatients with vivax malaria. Patients were distributed into two groups: group CPLA, given chloroquine 600 mg (single dose) on the first day of treatment, and two doses of placebo on second and third days. Group CHLO, given chloroquine 600 mg on first day and 450 mg on second and third day. Geometric means of the parasite density during the follow-up was similar in both groups. No differences were observed in the parasitological cure between the two groups (p = 0.442). There was clinical and parasitological efficacy in treatment of patients given a single-dose of chloroquine. This suggests that its restricted use could be indicated in remote areas of Brazilian Amazon Region, nevertheless the inadequate response of three patients indicates the need for further studies.<br>As regiões malarígenas da Amazônia brasileira têm se caracterizado por dificuldades no acesso ao tratamento e não aceitação das drogas pelos doentes. Com objetivos de avaliar a eficácia da cloroquina em dose simples de 600 mg, os autores realizaram um ensaio clínico duplo cego, placebo controlado em 132 pacientes portadores de malária por P. vivax. Os pacientes foram distribuídos em dois grupos: grupo CPLA que recebia 600 mg de cloroquina em dose simples no primeiro dia de tratamento e duas doses de placebo no segundo e terceiro dias de tratamento. Grupo CLO que recebia 600 mg de cloroquina no primeiro dia e 450 mg no segundo e terceiro dias. A média geométrica da densidade parasitária durante o seguimento foi similar em ambos os grupos. Não houve diferenças de cura parasitológica em ambos os grupos (p = 0,442). Observou-se eficácia clínica e parasitológica nos indivíduos que receberam dose simples de cloroquina, indicando a possibilidade de uso restrito a algumas áreas da Amazônia brasileira, contudo, a resposta inadequada de três pacientes sugere a necessidade de outros estudos