ABSTRACT
Social relationships are pivotal for human beings. Yet, we still lack a complete understanding of the types and conditions of social relationships that facilitate learning among children. Here, we present the results of a study involving 855 elementary school children from 14 different public schools in Chile designed to understand their social learning strategies in classrooms. We mapped students' social relationships using a behavioral experiment-a non-anonymous social dilemma-that allows us to measure cooperation and infer reciprocal and asymmetrical relationships between peers. We implemented the experiment synchronously in each classroom using networked tablets and a friendly user interface to mitigate cognitive barriers and boost students' engagement. Using regression models, we found a positive and significant association between reciprocity and academic performance. This result holds after controlling for class attendance, sex, parents' education, social status, individual cooperative dispositions, and fixed effects per class group. Finally, using a difference-in-difference framework, we found robust evidence that reciprocity heightens academic performance by comparing two consecutive academic semesters. This effect is heterogeneous and is considerably more prominent for the top 20% students experiencing higher levels of reciprocity in their social relationships. We expect these results to inform cooperative learning interventions in elementary education.
ABSTRACT
BACKGROUND: The significance of clinical and epidemiological rubella lies in its teratogenic effects on fetus; thus, rubella and congenital rubella represent great public health problems. OBJECTIVES: To determine the frequency of antibodies against rubella virus in early puerperium women, and to identify factors related to the absence of immunity against it. MATERIAL AND METHODS: During the period 2000-2002, a cross-sectional study was conducted. Women in puerperium period, residents of urban and rural areas of Delicias, Chihuahua, Mexico, were included. Women were interviewed and asked about factors that have been associated with the absence of immunity against rubella virus such as age, schooling, number of gestations, and residence area. We collected a blood sample between 1 and 6 hours after delivery, and anti-rubella IgG was determined. RESULTS: 396 patients aged 24 +/- 6 years were studied. The frequency of antibodies against rubella virus was of 87% (CI 95% 84-90). The factors related to the absence of antibodies against rubella were: number of gestations and schooling; patients whose pregnancy was the first or second gestation had a smaller frequency of antibodies against rubella virus (84%) compared to those with two previous gestations (95%, p = 0.03). CONCLUSION: The observed frequency of antibodies of rubella virus in this population is smaller than the informed one in industrialized countries. It is recommended to reinforce procedures of vaccination for susceptible women and after delivery, in order to prevent the infection consequences, as well as routinely carry out tests for detection of antibodies against rubella like protocol of premarital study.