Preliminary population study of Methylenetetrahydrofolate Reductase (MTHFR) C677T polymorphism determination in a pilot group of students from the University of Rosario

 Introduction: the 5, 10-methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme in folate metabolism; their polymorphisms have been associated with heart disease risk increase, obstetric problems, neural tube defects in fetuses and cancer susceptibility. This gene has a single nucleotide polymorphism, a C-T change at nucleotide 677, which affects significantly its enzymatic activity. Objective: because of the biological importance of this enzyme and the Colombian population genetic heterogeneity characteristic, a study was performed to determine allele and genotype frequencies of MTHFR C677T polymorphism in healthy individuals, taking into account that in Colombia there are only studies that have involved case-control methodology. Methods: we analyzed this polymorphism trough the amplification of the DNA of a 206 students sample population. Additionally, Colombian overall frequencies were calculated, using data from healthy controls reported in other studies. Results: a Hardy-Weinberg disequilibri m was found in the sample tested. For the Colombian data, we found that the global population was in equilibrium. Conclusion: T allele population frequency seems to be under positive selection pressure, which is reflected in the population allele increase, despite its deleterious effect. A Spanish study reported similar results and identified folic acid supplementation on expectant mothers as a probably cause of this change. 

Evaluation of strategic knowledge of students through authentic tasks of writingin science classroom

The difficulties at evaluating strategic knowledge have been connected to the use of deconxetualized tests that, at the end, do not involve the use of this knowledge. For this reason, an interest in developing authentic writing tasks that offer advantages for these kinds of evaluation have arisen. Throughout this research, authentic writing tasks were developed in a natural sciences class, with the purpose of evaluating the students' strategic knowledge. Different instruments were used to collect data, e.g. Interviews, questionnaires, a self-inform, as well as three samples of writing by the students, with the objective of analyzing the changes that occurred between one and the others, as well as to determine the decisions that students made in order to complete the assigned tasks successfully. An authentic writing task gives great opportunities to evaluate strategic knowledge. These tasks lead students to arrange their knowledge about the topic in hand, organize and adapt it to fit the objectives and the audience, also, it allows them to control and adjust their decisions on the task. This last stage became the perfect opportunity to take notes on the knowledge and regulation of cognitive processes that the students brought into play, as well as to evaluating their understanding of writing and the demands given on the different discursive genres. As a result, the students showed different degrees of strategic knowledge in the task. The students who showed a better strategic knowledge trust in their structural abilities know about discursive genres and have a good performance in basic linguistic abilities. The students who showed weak strategic knowledge distrust their writing skills, seem extremely worried about organizing the content of their texts, fail when checking their writings, and overlook or are unaware of the basic requirements of the discursive genre they are asked to exemplify. It appears that the previous knowledge and experiences at writing the students have been exposed to may affect the strategic knowledge shown when writing in this subject. 

Metacognitive knowledge and self-regulation: A qualitative lecture of students functioning in writing

This research emerges from the world-wide problematic concerning student's failure. It particularly analyzes the meta-cognitive competences in the writing process of this population. Based on Flavell's (1992) viewpoint about meta-cognition and the socio-cognitive approach of self-regulation, two variables were measured: meta-cognitive knowledge and self-regulation strategies. A qualitative study was conducted on a sample of 12 French students at first year university. This study uses a specific technique of interview known as "explicitation interview". The data analysis included the categorization, codification and quantification of the information obtained with the interviews. In conclusion, even though the students had metacognitive knowledge related to the written tasks, they did not show strategies that could help to go beyond the descriptive modality of written discourses by taking into account the readers' expectations. Their writing processes focused on transcription of ideas with little control on the planning and revision phases.

Behavioral differences in violence: the case of intra-group differences of paramilitaries and guerrillas in Colombia

In most studies on civil wars, determinants of conflict have been hitherto explored assuming that actors involved were either unitary or stable. However, if this intra-group homogeneity assumption does not hold, empirical econometric estimates may be biased. We use Fixed Effects Finite Mixture Model (FE-FMM) approach to address this issue that provides a representation of heterogeneity when data originate from different latent classes and the affiliation is unknown. It allows to identify sub-populations within a population as well as the determinants of their behaviors. By combining various data sources for the period 2000-2005, we apply this methodology to the Colombian conflict. Our results highlight a behavioral heterogeneity in guerrilla’s armed groups and their distinct economic correlates. By contrast paramilitaries behave as a rather homogenous group.

El juego una visión desde el maltrato infantil

Desde hace mucho tiempo una de las integrantes de este equipo de trabajo ha querido profundizar sobre la grave situación de maltrato infantil que viven un grupo vulnerable de niños y niñas colombianos. La revisión bibliográfica de este trabajo nos permite tener una visión general sobre los diferentes tipos de maltrato infantil, determinar las características individuales, familiares y sociales y las consecuencias a nivel del desarrollo psicológico, cognitivo y social de los menores.