Do Cognitive Test Scores Explain Higher U.S. Wage Inequality?

Using microdata from the 1994-8 International Adult Literacy Survey (IALS) for nine countries, we examine the role of cognitive skills in explaining higher wage inequality in the United States. We find that while the greater dispersion of cognitive test scores in the United States plays a part in explaining higher U.S. wage inequality, higher labor market prices (i.e., higher returns to measured human capital and cognitive performance) and greater residual inequality still play important roles, and are, on average, quantitatively considerably more important than differences in the distribution of test scores in explaining higher U.S. wage inequality

Self-reported health and health care use in an ageing population in the Agincourt sub-district of rural South Africa.

BACKGROUND: South Africa is experiencing a demographic and epidemiological transition with an increase in population aged 50 years and older and rising prevalence of non-communicable diseases. This, coupled with high HIV and tuberculosis prevalence, puts an already weak health service under greater strain. OBJECTIVE: To measure self-reported chronic health conditions and chronic disease risk factors, including smoking and alcohol use, and to establish their association with health care use in a rural South African population aged 50 years or older. METHODS: The Study on Global Ageing and Adult Health (SAGE), in collaboration with the INDEPTH Network and the World Health Organization, was implemented in the Agincourt sub-district in rural northeast South Africa where there is a long-standing health and socio-demographic surveillance system. Household-based interviews were conducted in a random sample of people aged 50 years and older. The interview included questions on self-reported health and health care use, and some physical measurements, including blood pressure and anthropometry. RESULTS: Four hundred and twenty-five individuals aged 50 years or older participated in the study. Musculoskeletal pain was the most prevalent self-reported condition (41.7%; 95% Confidence Interval [CI] 37.0-46.6) followed by hypertension (31.2%; 95% CI 26.8-35.9) and diabetes (6.1%; 95% CI 4.1-8.9). All self-reported conditions were significantly associated with low self-reported functionality and quality of life, 57% of participants had hypertension, including 44% of those who reported normal blood pressure. A large waist circumference and current alcohol consumption were associated with high risk of hypertension in men, whereas in women, old age, high waist-hip ratio, and less than 6 years of formal education were associated with high risk of hypertension. Only 45% of all participants reported accessing health care in the last 12 months. Those who reported higher use of the health facilities also reported lower levels of functioning and quality of life. CONCLUSIONS: Self-reported chronic health conditions, especially hypertension, had a high prevalence in this population and were strongly associated with higher levels of health care use. The primary health care system in South Africa will need to provide care for people with non-communicable diseases

Stroke in rural South Africa - contributing to the little known about a big problem

Objectives. To describe the extent of mortality from cerebrovascular accident (CVA) in a rural South African population.Design. Annual demographic and health surveillance with verbal autopsy of all deaths, 1992 - 1995.Outcome measures. Stroke mortality rate by age and sex.Results. Stroke mortality increased with age and is higher in men than women over age 35. Proportionate mortality ratio from CVA: 10.3% of deaths in the 35 - 64-year age group.Conclusion. Cerebrovascular disease is an important cause of death in South Africa's rural north-east. Community-based research is needed to inform policy and practice

The implications of long term community involvement for the production and circulation of population knowledge

Demographic surveillance systems (DSS) depend on community acceptance and involvement to produce high quality longitudinal data. Ensuring community support also exposes power relations usually concealed in the research process. We discuss the Agincourt Health and Demographic Surveillance System in South Africa to argue that: 1) long-term presence and community involvement contribute to high response rates and data quality, 2) to maintain community support the project must demonstrate its usefulness, 3) reporting to community members provides valuable checks on the local relevance and comprehension of questions, and 4) community opinion can modify both wording and content of research questions.community, demographic surveillance system, fertility, health, knowledge, longitudinal, migration, mortality, South Africa

Multi-Period Trading via Convex Optimization

We consider a basic model of multi-period trading, which can be used to evaluate the performance of a trading strategy. We describe a framework for single-period optimization, where the trades in each period are found by solving a convex optimization problem that trades off expected return, risk, transaction cost and holding cost such as the borrowing cost for shorting assets. We then describe a multi-period version of the trading method, where optimization is used to plan a sequence of trades, with only the first one executed, using estimates of future quantities that are unknown when the trades are chosen. The single-period method traces back to Markowitz; the multi-period methods trace back to model predictive control. Our contribution is to describe the single-period and multi-period methods in one simple framework, giving a clear description of the development and the approximations made. In this paper we do not address a critical component in a trading algorithm, the predictions or forecasts of future quantities. The methods we describe in this paper can be thought of as good ways to exploit predictions, no matter how they are made. We have also developed a companion open-source software library that implements many of the ideas and methods described in the paper

Introducing visual participatory methods to develop local knowledge on HIV in rural South Africa

The authors would also like to acknowledge the field staff at the MRC/Wits Agincourt unit, particularly Ms Rirhandzu Debs and Dr Kerstin Edin from the Umeå Centre for Global Health Research, Umeå University, who facilitated data collection and made important contributions to the fieldwork.Peer reviewedPublisher PD

Snakebite: An Exploratory Cost-Effectiveness Analysis of Adjunct Treatment Strategies.

The cost-effectiveness of the standard of care for snakebite treatment, antivenom, and supportive care has been established in various settings. In this study, based on data from South Indian private health-care providers, we address an additional question: "For what cost and effectiveness values would adding adjunct-based treatment strategies to the standard of care for venomous snakebites be cost-effective?" We modeled the cost and performance of potential interventions (e.g., pharmacologic or preventive) used adjunctively with antivenom and supportive care for the treatment of snakebite. Because these potential interventions are theoretical, we used a threshold cost-effectiveness approach to explore this forward-looking concept. We examined economic parameters at which these interventions could be cost-effective or even cost saving. A threshold analysis was used to examine the addition of new interventions to the standard of care. Incremental cost-effectiveness ratios were used to compare treatment strategies. One-way, scenario, and probabilistic sensitivity analyses were conducted to analyze parameter uncertainty and define cost and effectiveness thresholds. Our results suggest that even a 3% reduction in severe cases due to an adjunct strategy is likely to reduce the cost of overall treatment and have the greatest impact on cost-effectiveness. In this model, for example, an investment of $10 of intervention that reduces the incidence of severe cases by 3$75 per individual. These findings illustrate the striking degree to which an adjunct intervention could improve patient outcomes and be cost-effective or even cost saving

Comparative interference by haemolysis in automated assays for bilirubin at multiple analyte concentrations

The negative interference caused by haemolysis in manual bilirubin assays contrasts with the positive interference reported for some automated methods utilizing the same basic chemistry. A comparison was therefore made of the haemolysis interference associated with several automated bilirubin methodologies: multilayer film (Kodak Ektachem- total bilirubin (TBil), direct bilirubin (DBil), conjugated bilirubin (Bc), unconjugated bilirubin (Bu),; tableted reagents (Baxter Paramax- TBil, DBil); continuous flow (Technicon SMAC — TBil). Thirty serum pools were analysed (five concentrations of bilirubin, 2-229 μmol/l; six concentrations of haemoglobin, 0.00002-0.052 mmol/1). All methods, except one (Bc), exhibited both positive and negative interference, depending upon the relative haemoglobin and bilirubin concentrations. This interference, at any given haemoglobin concentration, was neither constant nor proportional with increasing bilirubin concentration. These complex patterns of interference suggest that the best characterization of interference is obtained when (1) both percentage-difference and absolute-difference ‘interferographs’ are plotted; and (2) the interference is determined at multiple analyte concentrations

Efficient Code Generation from SHIM Models

Programming concurrent systems is substantially more difficult than programming sequential systems, yet most embedded systems need concurrency. We believe this should be addressed through higher-level models of concurrency that eliminate many of the usual challenges, such as nondeterminism arising from races. The shim model of computation provides deterministic concurrency, and there already exist ways of implementing it in hardware and software. In this work, we describe how to produce more efficient C code from shim systems. We propose two techniques: a largely mechanical one that produces tail-recursive code for simulating concurrency, and a more clever one that statically analyzes the communication pattern of multiple processes to produce code with far less overhead. Experimentally, we find our tail-recursive technique produces code that runs roughly twice as fast as a baseline; our statically-scheduled code can run up to twelve times faster

Large area polysilicon films with predetermined stress characteristics and method for producing same

Multi-layer assemblies of polysilicon thin films having predetermined stress characteristics and techniques for forming such assemblies are disclosed. In particular, a multi-layer assembly of polysilicon thin films may be produced that has a stress level of zero, or substantially so. The multi-layer assemblies comprise at least one constituent thin film having a tensile stress and at least one constituent thin film having a compressive stress. The thin films forming the multi-layer assemblies may be disposed immediately adjacent to one another without the use of intermediate layers between the thin films. Multi-layer assemblies exhibiting selectively determinable overall bending moments are also disclosed. Selective production of overall bending moments in microstructures enables manufacture of such structures with a wide array of geometrical configurations