Model-based analyses: Promises, pitfalls, and example applications to the study of cognitive control

We discuss a recent approach to investigating cognitive control, which has the potential to deal with some of the challenges inherent in this endeavour. In a model-based approach, the researcher defines a formal, computational model that performs the task at hand and whose performance matches that of a research participant. The internal variables in such a model might then be taken as proxies for latent variables computed in the brain. We discuss the potential advantages of such an approach for the study of the neural underpinnings of cognitive control and its pitfalls, and we make explicit the assumptions underlying the interpretation of data obtained using this approach

Enhanced oil recovery: environmental issues and state regulatory programs

Environmental assessments were prepared for nine EOR demonstration projects located in six states, and the oil regulations for all oil-producing states were reviewed. These evaluations revealed a number of potentially important environmental impacts associated with EOR, including: (1) loss of vegetation; (2) excessive air emissions from thermal operations; (3) excessive erosion and sedimentation (mostly in hilly terrain) and subsequent deterioration of surface-water quality; (4) pollution of land and surface waters from spills or leaks of oil or other chemicals; and (5) contamination of groundwater aquifers. The need for additional environmental planning and monitoring regulations specific for the oil-production industry is emphasized. States are encouraged to continue strengthening and upgrading their oil-regulatory programs to safeguard the environment. The evaluations also identified areas where additional information is needed: (1) toxicity and carcinogenicity studies of chemicals used in injection processes; (2) evaluation of groundwater monitoring methods; and (3) studies of reclamation procedures for soils contaminated by oil and brine

Type A behaviour and prevalent heart disease in the Caerphilly study: increase in risk or symptom reporting?

Type A behaviour was assessed by modified Framingham scale in a total sample of 1956 employed men in the Caerphilly study. Prevalent heart disease was measured by cardiovascular questionnaire to obtain evidence of myocardial infarction and angina, and by electrocardiogram (ECG) for evidence of ischaemia. Type A was inversely related to age and systolic blood pressure and was positively related to social class and height. It was not related to serum cholesterol or alcohol consumption. After control for age, systolic blood pressure, height, smoking and social class, type A was found to be independent of angina but positively associated with an increased risk of possible myocardial infarction (MI). Type A was also associated with increased risk of confirmed MI. An inverse association was found between type A and asymptomatic ischaemic heart disease (IHD). The association between type A and symptomatic IHD could be due to symptom reporting