Situated cognition and the culture of learning

Includes bibliographical references (p. 16-17

The analysis of reading tasks and texts

Bibliography : p. 78-8

Cognitive apprenticeship : teaching the craft of reading, writing, and mathtematics

Includes bibliographical references (p. 25-27)This research was supported by the National Institute of Education under Contract no. US-NIE-C-400-81-0030 and the Office of Naval Research under Contract No. N00014-85-C-002

Association of hematocrit value with cardiovascular morbidity and mortality in incident hemodialysis patients

Association of hematocrit value with cardiovascular morbidity and mortality in incident hemodialysis patients.BackgroundAssociations between hematocrit values and clinical outcome have been studied with conflicting results in cardiac patients, end-stage renal disease (ESRD) patients, and ESRD patients with cardiac disease. We studied dialysis patients to determine the relationship between hematocrit value and cardiac risk under current Dialysis Outcomes Quality Initiative (DOQI) practices.MethodsMedicare data were used to study 50,579 incident hemodialysis patients selected from January 1, 1998, to December 31, 1999, who received hemodialysis for 9 months after the onset of ESRD. Patients were divided into groups on the basis of the hematocrit value: ≤30%, >30% to ≤33%, >33% to ≤36%, >36% to ≤39%, and >39%. For hospitalization, the follow-up extended to 21/2 years; for mortality, 3 years.ResultsCompared to patients with hematocrit values of >33% to ≤36%, patients with values of >36% to ≤39% and those with values of >39% had risk ratios for hospitalization due to cardiac disease of 0.92 (95% CI 0.88 to 0.97) and 0.79 (95% CI 0.72 to 0.87), respectively, and risk ratios for death due to cardiac disease of 0.92 (95% CI 0.87 to 0.98) and 0.83 (95% CI 0.74 to 0.93), respectively, in the follow-up period.ConclusionThe significant associations we report do not establish a causal relationship between higher hematocrit values and lower risks of cardiac morbidity and mortality. A randomized clinical trial in low-risk patients is needed to establish causality

Reproduction of Spanish Mackerel, Scomberomorus maculatus, from the Southeastern United States

Spanish mackerel, Scomberomorus maculatus, were collected during 1977-80 in the Gulf of Mexico and from North Carolina to south Florida during 1980-81 to describe their reproductive biology. The major spawning period extended from May to September in all areas and peaked during the spring and early summer. Most fish were mature at about 350 mm FL, but size at maturity varied between sexes and sampling areas. Males matured at a smaller size than females. Fecundity was estimated from 52 fish from all areas and ranged from about 100,000 eggs for a 328 mm (295 g) fish to 2,113,000 eggs for a 626 mm (2,415 g) fish. Fork length and total weight were equally good predictors of fecundity