Key findings from the 2006 Scottish Health Behaviour in School-aged Children study

The HBSC study in Scotland is funded by NHS Health Scotland.Publisher PD

Dermatological manifestations of measles infection in hospitalised paediatric patients observed in the 2009 - 2011 Western Cape epidemic

Introduction. Measles is an acute vaccine-preventable infection common in childhood. In this study, the common dermatological signs of measles were designated the ‘classic dermatological measles syndrome’.Methods. We attempted to ascertain the prevalence of ‘non-classic’ dermatological measles presentation in 69 paediatric patients admitted to New Somerset Hospital, Western Cape, during the recent South African measles outbreak. The patients were examined and photographed, after informed consent had been obtained, and findings were assessed by 1 dermatology consultant and 6 dermatology registrars. Measles infection was confirmed in 38 of the patients by means of IgM testing. The data were analysed using Stata version 11.1 statistical software.Outcomes. Of the group, 17.4% (95% confidence interval (CI) 8.2 - 26.6%) displayed a ‘classic’ measles dermatological picture, although all had been clinically diagnosed and admitted as complicated measles cases. Of those serologically confirmed to have measles (N=38), 26.3% (95% CI 11.6 - 40.9%) conformed to the ‘classic’ dermatological picture. Therefore, a significant majority of these patients presented with what was considered in this study to be a ‘non-classic’ dermatological picture.Conclusions. Measles infection in a paediatric population requiring admission may frequently present without a full-house ‘classic’ dermatological picture. Recognised signs in isolation may be of greater value than the classically described syndrome as a whole. ‘Non-classic’ dermatological forms may occur more frequently than anticipated in complicated cases needing admission. Skin necrosis may be associated with measles.S Afr Med J 2012;102(6):356-35

High Spatial Resolution BRDFs with Metallic powders Using Wave Optics Analysis

This manuscript completes the analysis of our SIGGRAPH 2013 paper "Fabricating BRDFs at High Spatial Resolution Using Wave Optics" in which photolithography fabrication was used for manipulating reflectance effects. While photolithography allows for precise reflectance control, it is costly to fabricate. Here we explore an inexpensive alternative to micro-fabrication, in the form of metallic powders. Such powders are readily available at a variety of particle sizes and morphologies. Using an analysis similar to the micro-fabrication paper, we provide guidelines for the relation between the particles' shape and size and the reflectance functions they can produce

Clustering based on adherence data

Adherence to a medical treatment means the extent to which a patient follows the instructions or recommendations by health professionals. There are direct and indirect ways to measure adherence which have been used for clinical management and research. Typically adherence measures are monitored over a long follow-up or treatment period, and some measurements may be missing due to death or other reasons. A natural question then is how to describe adherence behavior over the whole period in a simple way. In the literature, measurements over a period are usually combined just by using averages like percentages of compliant days or percentages of doses taken. In the paper we adapt an approach where patient adherence measures are seen as a stochastic process. Repeated measures are then analyzed as a Markov chain with finite number of states rather than as independent and identically distributed observations, and the transition probabilities between the states are assumed to fully describe the behavior of a patient. The patients can then be clustered or classified using their estimated transition probabilities. These natural clusters can be used to describe the adherence of the patients, to find predictors for adherence, and to predict the future events. The new approach is illustrated and shown to be useful with a simple analysis of a data set from the DART (Development of AntiRetroviral Therapy in Africa) trial in Uganda and Zimbabwe

Combining national survey with facility-based HIV testing data to obtain more accurate estimate of HIV prevalence in districts in Uganda.

BACKGROUND: National or regional population-based HIV prevalence surveys have small sample sizes at district or sub-district levels; this leads to wide confidence intervals when estimating HIV prevalence at district level for programme monitoring and decision making. Health facility programme data, collected during service delivery is widely available, but since people self-select for HIV testing, HIV prevalence estimates based on it, is subject to selection bias. We present a statistical annealing technique, Hybrid Prevalence Estimation (HPE), that combines a small population-based survey sample with a facility-based sample to generate district level HIV prevalence estimates with associated confidence intervals. METHODS: We apply the HPE methodology to combine the 2011 Uganda AIDS indicator survey with the 2011 health facility HIV testing data to obtain HIV prevalence estimates for districts in Uganda. Multilevel logistic regression was used to obtain the propensity of testing for HIV in a health facility, and the propensity to test was used to combine the population survey and health facility HIV testing data to obtain the HPEs. We assessed comparability of the HPEs and survey-based estimates using Bland Altman analysis. RESULTS: The estimates ranged from 0.012 to 0.178 and had narrower confidence intervals compared to survey-based estimates. The average difference between HPEs and population survey estimates was 0.00 (95% CI: - 0.04, 0.04). The HPE standard errors were 28.9% (95% CI: 23.4-34.4) reduced, compared to survey-based standard errors. Overall reduction in HPE standard errors compared survey-based standard errors ranged from 5.4 to 95%. CONCLUSIONS: Facility data can be combined with population survey data to obtain more accurate HIV prevalence estimates for geographical areas with small population survey sample sizes. We recommend use of the methodology by district level managers to obtain more accurate HIV prevalence estimates to guide decision making without incurring additional data collection costs

Fabricating BRDFs at high spatial resolution using wave optics

Recent attempts to fabricate surfaces with custom reflectance functions boast impressive angular resolution, yet their spatial resolution is limited. In this paper we present a method to construct spatially varying reflectance at a high resolution of up to 220dpi, orders of magnitude greater than previous attempts, albeit with a lower angular resolution. The resolution of previous approaches is limited by the machining, but more fundamentally, by the geometric optics model on which they are built. Beyond a certain scale geometric optics models break down and wave effects must be taken into account. We present an analysis of incoherent reflectance based on wave optics and gain important insights into reflectance design. We further suggest and demonstrate a practical method, which takes into account the limitations of existing micro-fabrication techniques such as photolithography to design and fabricate a range of reflection effects, based on wave interference.United States-Israel Binational Science FoundationIntel Corporation (Intel Collaborative Research Institute for Computational Intelligence)National Science Foundation (U.S.) (CGV 1116303

Dermatological manifestations of measles infection in hospitalised paediatric patients observed in the 2009 - 2011 Western Cape epidemic

Introduction. Measles is an acute vaccine-preventable infection common in childhood. In this study, the common dermatological signs of measles were designated the ‘classic dermatological measles syndrome’. Methods. We attempted to ascertain the prevalence of ‘non-classic’ dermatological measles presentation in 69 paediatric patients admitted to New Somerset Hospital, Western Cape, during the recent South African measles outbreak. The patients were examined and photographed, after informed consent had been obtained, and findings were assessed by 1 dermatology consultant and 6 dermatology registrars. Measles infection was confirmed in 38 of the patients by means of IgM testing. The data were analysed using Stata version 11.1 statistical software. Outcomes. Of the group, 17.4% (95% CI 8.2 - 26.6%) displayed a classic measles dermatological picture, although all had been clinically diagnosed and admitted as complicated measles cases. Those serologically confirmed to have measles (N=38), 26.3% (95% CI 11.6 - 40.9%) conformed to the classic dermatological picture. Therefore, a significant majority of these patients presented with what was considered in this study to be a ‘non-classic’ dermatological picture. Conclusions. Measles infection in a paediatric population requiring admission may frequently present without a full-house classic dermatological picture. Recognised signs in isolation may be of greater value than the classically described syndrome as a whole. ‘Non-classic’ dermatological forms may occur more frequently than anticipated in complicated cases needing admission. Skin necrosis may be associated with measles

Power market models for the clean energy transition: State of the art and future research needs

As power systems around the world are rapidly evolving to achieve decarbonization objectives, it is crucial that power system planners and operators use appropriate models and tools to analyze and address the associated challenges. This paper provides a detailed overview of the properties of power market models in the context of the clean energy transition. We review common power market model methodologies, their readiness for low- and zero‑carbon grids, and new power market trends. Based on the review, we suggest model improvements and new designs to increase modeling capabilities for future grids. The paper highlights key modeling concepts related to power system flexibility, with a particular focus on hydropower and energy storage, as well as the representation of grid services, price formation, temporal structure, and the importance of uncertainty. We find that a changing resource mix, market restructuring, and growing price uncertainty require more precise modeling techniques to adequately capture the new technology constraints and the dynamics of future power markets. In particular, models must adequately represent resource opportunity costs, multi-horizon flexibility, and energy storage capabilities across the full range of grid services. Moreover, at the system level, it is increasingly important to consider sub-hourly time resolution, enhanced uncertainty representation, and introduce co-optimization for dual market clearing of energy and grid services. Likewise, models should capture interdependencies between multiple energy carriers and demand sectors.publishedVersio