Amniotic fluid calcium concentration in the prenatal diagnosis of cystic fibrosis

Calcium concentrations were measured in supernatant amniotic fluid in order to establish whether they may be used as a marker for cystic fibrosis. No difference in values were found, whether the sample was derived from a normal pregnancy or from a pregnancy which resulted in a baby affected with cystic fibrosis.     

Soil erosion in developing countries: A politicoeconomic explanation

Soil erosion is accelerating in developing countries of Asia, Africa, and Latin America. It has threatened the livelihood of millions of peasants, for agriculture is their economic mainstay. A probe into the forces causing erosion reveals that the elite’s resolve to accumulate ever more wealth and to maintain, consolidate, or expand their sociopolitical power and the necessity of the poor to fulfill their requirements of food, fuelwood, and fodder are the two major factors accelerating soil erosion. Unless the vast masses of poor people are integrated into the national mainstream through the implementation of equitable and redistributive development policies, it is impossible to control the accelerating rate of soil erosion and thus to achieve the objective of sustainable development. In this article, the phenomenon “soil erosion” is studied with the sol e focus on causation through anthropogenic factors.     

The impact of feedback and self-efficacy on performance in training

This field experiment examined the main and interactive effects of self-efficacy and feedback (i.e. the use of feedback versus no feedback) on performance in a speed reading class. Results showed that the provision of feedback was beneficial to the performance of all subjects, however as subject self-efficacy increased, the beneficial effects of feedback to the subject's performance also increased. Subjects who received feedback on their performance experienced significantly greater increases in self-efficacy than subjects who received no feedback. The more positive the performance feedback received, the greater the increase in individual self-efficacy. The implications of these results for training programs are discussed.     

ALGAL BLOOM PROBABILITY IN A LARGE SUBTROPICAL LAKE1

ABSTRACT: Algal blooms, defined as chlorophyll α concentrations greater than 40 μg l^?1, are common in Lake Okeechobee, Florida. Using logistic regression techniques, we have developed equations that relate limnological variables to algal bloom occurrence in four distinct open-water regions of this large shallow lake: central pelagic, northwest, southwest, and a transition region between the western and pelagic regions. Wind velocity and total phosphorus, which are closely related to resuspended material in the central region, are negatively related to algal bloom occurrence there. In the transition region, algal bloom occurrence is positively related to total nitrogen and wind velocity. Algal bloom occurrence is strongly and positively related to total nitrogen and total phosphorus concentrations in the western regions. The logistic regression model predicts an algal bloom probability greater than 95 percent in the northwest region when total phosphorus exceeds 0.10 mg l^?1 and total nitrogen exceeds 2.5 mg l^?1. In the southwest region the model predicts algal bloom probability of 100 percent when total phosphorus exceeds 0.10 mg l^?1 and total nitrogen exceeds 2.8 mg l^?1. Given 1994 mean total phosphorus concentrations of 0.05 and 0.04 mg l^?1 in the northwest and southwest regions, respectively, total nitrogen would have to remain below 1.32 and 1.43 mg l^?1, respectively, to keep the algal bloom probability below 10 percent. Because the lake is heterogenous, such nutrient standards should be considered on an in-lake regional basis for Lake Okeechobee.