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C S Hammen

Publications and source records attributed to C S Hammen.

10 recordsLinked to original sources

Attendance and grades in a human physiology course.

Teaching a lecture course in introductory human physiology with 40-183 students provided an opportunity to test the hypothesis that regular attendance is correlated with higher examination scores. Data on 556 students were recorded during five semesters, each consisting of three classes per week for 14 weeks. The students were in the second year of pharmacy, nursing, physical education, and dental hygiene programs. Attendance was recorded in each class. Regular attendance was encouraged but was not used to influence scores. The maximum possible score was 400 points, based on two 1-h examinations and a 2-h final examination. Examinations consisted of multiple-choice questions derived from reading assignments in a required textbook. Linear regression analysis indicated a small negative relation between total point scores and absences, amounting to an average decrease of 2 points for each absence, or a decrease of 0.5% per absence. Correlation coefficients averaged -0.33. The results suggest that regular attendance was helpful in a statistical sense but was not a decisive factor in learning human physiology as presented in current textbooks.

Education, Medical↗

Determination of isocitrate lyase and malate synthase activities in a marine bivalve mollusk by a new method of assay.

1. A new method for the assay of isocitrate lyase (EC 4.1.3.1) was developed, based on the isolation of 14C-glyoxylate semicarbazone by co-crystallization with authentic carrier. The method was easily adapted to measure malate synthase (EC 4.1.3.2). 2. Interfering reactions were avoided with this method, and isocitrate dehydrogenase (ID) was easily distinguished from isocitrate lyase (IL). Assay of IL in germinating pumpkin seeds gave rates proportional to the amount of extract, with greater sensitivity and less variability than the spectrophotometric method. 3. Six species of marine bivalve mollusks were tested for IL activity, and two species produced glyoxylate: Crassostrea virginica at 0.10 mumol/hr/g tissue, and Petricola pholadiformis at 0.85 mumol/hr/g. The other four species, and four other marine invertebrates from other phyla, lacked detectable IL activity. 4. The rate of disappearance of glyoxylate in the malate synthase (MS) reaction indicated that Petricola had an activity of 0.60 mumol/hr/g: this is the first demonstration of activities of both IL and MS in a marine invertebrate.

Animals↗