Instructional patterns for the teaching and learning of argumentative writing in high school English language arts classrooms

Reading and Writing - Argumentative writing has long been considered an essential skill for disciplinary learning. For researchers and curriculum developers to develop ecologically valid...     

Using rapid application development to improve the usability of a preservice teacher technology course

The aim of this research was to examine the use of a rapid application development (RAD) approach in improving the usability (effectiveness, efficiency, and appeal) of instructional materials for preservice teachers. The RAD approach used was the analysis, synthesis, evaluation and change (ASEC) model (Reigeluth & Nelson, 1997). After examining existing materials, 11 units of instruction were prototyped, tested, modified, and retested with the requisite changes being implemented over the course of three semesters. Qualitative and quantitative data were collected from 570 students, 7 instructional designers, and 4 lab assistants. Results of the study showed significant increases in usability scores between the second and third semester. Both positive and negative experiences in using a rapid development model are discussed.     

Automatic recommendation system based on hybrid filtering algorithm

Education and Information Technologies - Web recommendation systems are ubiquitous in the world used to overcome the product overload on e-commerce websites. Among various filtering algorithms,...     

Educational attainment and HIV/AIDS prevalence: A cross-country study

Using data for a large cross-country sample, a reasonable model is estimated to judge the effect of adult educational attainment on prevalence of HIV. Three main points are noted. First, there is an indication of a significantly negative effect of educational attainment on HIV prevalence. Second, magnitude of the impact appears sizable. Third, a simple test suggests that the model does not have any major specification problem. Three additional aspects may also be interesting. First, the impact of per capita income is negative but statistically weak. Second, the effect of health expenditures lacks significance and does not carry the expected sign. Third, the proportion of population that is Muslim has a significantly negative association with HIV prevalence, perhaps reflecting the widely-shared view that male circumcision lowers acquisition of the disease.     

Inhibitory effect of metalloporphyrins in conjunction with cholesterol on hepatic phospholipase A2 activityin vivo in rats

We investigated the effect of cholesterol and the metalloporphyrins cobalt mesoporphyrin (CoMP) and chromium protoporphyrin (CrPP) on phospholipase A₂ (PLA₂) activity and the consequent hepatic mitochondrial stability as well as on lipid concentrations. Our studies revealed that on administration of cholesterol, CrPP, CoMP as well as simultaneous adminstration of cholesterol and CrPP, there was an inhibition of PLA₂ activity. These moieties may therefore, be agents for preventing destabilisation of the mitochondrial membrane and the consequent pathological conditions which may arise due to membrane lysis. Our results revealed that cholesterol administration increased phospholipid concentration, albeit by modest amounts. Although the independent administration of metalloporphyrins led only to minor elevations in phospholipid concentration, the simultaneous administration of cholesterol and CrPP generated a steep elevation in the concentration of total phospholipid. Since cholesterol inhibits PLA₂ activity it has the potential of being therapeutic agent for preventing the pathological conditions which may arise due to membrane lysis.