Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

This research was intended to identify scientific thinking skills such as argumentation and use of analogies that are emphasized in preparing Costa Rican students to participate in the International Biology Olympics. It is important to explore the types of instruction provided in the training process of students that represent the country in Central American, Ibero-American and World Olympics, since the creation of comprehensively trained individuals should be promoted to provide scientifically competent people who can become agents of transformation in diverse environments.  The investigation was carried out between May and November of 2018, working with 16 students, at least 1 student of each edition, and 8 tutors or professors specialized in various areas of biology. Interviews, case studies and observation were used to collect data. The main results indicated that the preparation processes for competing in the International Biology Olympics promoted scientific thinking skills, and that the use of arguments in a variety of student-tutor interactions, as well as the use of analogies, mainly by the students, served as a way to for students to better understand and internalize content. It is concluded that argumentation should be emphasized in the preparation of students as a way to better explain what they are learning; they always question the usefulness of what they learn in both personal and social terms. On the other hand, analogies are literary devices that enable better understanding of content by allowing students to relate what they are learning to what they already know.

This article presents a case study on the meanings that beginning students of mathematics teaching assign to the Pythagorean theorem. In this study, emphasis was placed on one of the most important elements used for structuring a curriculum: the ways in which students of mathematics teaching make use of a mathematical concept. Twenty (20) students of Mathematics Teaching from the four public universities of Costa Rica that offer this career participated in the study. A questionnaire was designed and applied for collecting information, which consisted of 7 items which presented and solved tasks based on the use of the Pythagorean theorem. Answers to two of these items stand out, which are associated with the phenomenology of a mathematical concept. Content analysis, one of the components of didactic analysis, was used to examine and characterize teaching situations, together with the contexts proposed by this group of students for the statement and solution of mathematics tasks associated with the theorem. The results show that this theorem was mainly seen as a tool for solving mathematical tasks related to the calculation of lengths. Additionally, participants experienced some difficulties in proposing tasks based on non-mathematical situations, and the quality of the tasks proposed varies.

Quantifying and measuring the water footprint allows for the analysis and control over the environmental management of the institution and helps integrate college population, thus directing all efforts towards a sustainable development. The objective of this research is to quantify and calculate the institutional blue water footprint for the 2012-2016 period to analyze and compare its behavior over time, according to the variables included in the calculation such as consumption of water, fossil fuel, reams of paper and electrical energy (since they are important for the function and performance of institutional activities). The methodology applied was the one described by Hoekstra and Chapagain in the Water Footprint Assessment Manual, as well as the water footprint and virtual water factors taken from the Water Footprint Network. The corresponding amount was obtained for each item.  As a result, between 2012 and 2015, the Institutional Water Footprint decreased 8%, from 966 432 m3 to 888 693 m3, while in 2016 it slightly increased to 891 976 m3

The document addresses the problem of low academic performance in Mathematics (LPM). Its principal objective is to analyze how academic performance relates to attitudes towards this subject, perceptions of self-efficacy, social development and the educational level of students’ mothers. One hundred and ninety-seven (197) students in the 7th, 8th and 9th grades of middle and high school, between 13 and 16 years old, participated in the study. This correlational study used techniques of exploratory factor analysis and multiple regression to determine the association between the constructs. The results confirm the importance of students trusting in their abilities when performing mathematical tasks, which is reflected on the significant coefficients for the dimensions of confidence (p = 0.001) and master experience (p <0.001), but the educational level of the mother did not have a significant effect on learning outcomes. Unexpected results were also found with respect to social development and some dimensions of the scale of attitudes towards mathematics, but the impacts of these constructs and self-efficacy on LPM were verified. Based on these findings, it is recommended to carry out further research on the effects of these factors.

This article presents data on the identification of factors that influence student dropout and failure to pass a university-level mathematics course. Research was based on a mixed quantitative-qualitative design, using a predominantly quantitative approach. Questionnaires, interviews and a focus group were used to collect data from students, and a questionnaire was also applied to teachers. Data on student characteristics such as sex, area of origin, type of school or institution in which they finished secondary education, year of admission to university education, average of secondary education grades, university admission examination grade, course enrollment category, schedule of the group in which they enrolled, and career selected allowed the identification of students at risk of dropping out or failing a course. Among the most important reasons that students failed a course were lack of dedication to the study of course topics, poor study habits, deficiencies in necessary background knowledge, prioritization of other courses that a student was enrolled in, and lack of interest in studying. In the case of dropping out, important contributing factors included poor performance in the first course examination, prioritization of other courses, deficiencies in background knowledge, lack of interest, and low levels of dedication studying for the course. Based on these results, there is a need to review the topics included in the course curriculum, and to establish strategies that assure that students with weak backgrounds in mathematics are enrolled in an introductory mathematics course at the university level.

The generalized extreme value distribution (GEVD) was used to model extreme rainfall events in Central America for a period of 30 years, beginning in 1971. Data consisted of daily rainfall records of 103 meteorological stations located throughout the isthmus. Central America was divided into 3 regions: Pacific, Caribbean and an intermediate zone. A bootstrap hypothesis test was used to compare the parameters of location, scale and form of the 3 regions. The results of the study showed significant differences between the 3 regions, mainly in terms of location and scale parameters.

The Monster of Troy, depicted in a 6th Century BC Corinthian vase, has been proposed to be the earliest artistic record of a vertebrate fossil, possibly a Miocene giraffe (Samotherium sp.). The purpose of the paper was to analyze the giraffe hypothesis using four approaches: a double-blind random design in which 78 biologists compared the vase skull with Samotherium and several reptiles; an informed survey of 30 art and science students who critically assessed the hypothesis based on images of candidate species; an objective computerized mathematical comparison of the images; and a detailed morphological comparison of the skulls. All of the participants rejected the giraffe hypothesis. The types of eyes and teeth unambiguously discard a mammal, whether fossil or living, as the model.  The model was most likely an extant carnivorous reptile of the Varanidae family.

Access to higher education is only a first step in achieving equity in education; the following step is improving student retention, or lowering dropout rates, which is the same thing. The present study focused on the definition of an index as an estimator of the risk of individuals dropping out of a university using a Markov chain model, based on the randomness of the occurrence of dropping out. The suggested index was applied to a sample of 5,700 university students from the 2012-2015 annual cohorts of 8 university departments of a public regional university in Chile. The results indicate that the highest average probability of dropping out (slightly more than 39%) occurs in the first 2 semesters of university studies, and then decreases through time. This indicates the need for institutional retention policies that pay particular attention to the first year of university studies. Having this index also allows a formal estimation of changes or temporary variations in the risk, as well as quantifying the impact of interventions, not only for the case under study but for the entire higher education system.

La simbiosis entre rizobios y alfalfa (Medicago sativa L.) contribuye a la incorporación de nitrógeno en los agroecosistemas a través de la fijación biológica, que dependerá de la adecuada provisión de nutrientes disponibles en el suelo. El objetivo de este trabajo fue evaluar el efecto de la inoculación con Ensifer meliloti y la fertilización con 0, 20 y 40 kg/ha de fósforo sobre la nodulación y productividad de una pastura de alfalfa en el centro de la provincia de Santa Fe. La inoculación y la aplicación de dosis crecientes de fósforo aumentaron el número de nódulos, biomasa nodular y la producción del forraje de las plantas. La técnica de la inoculación condujo a un incremento de la producción de materia seca entre 23 y 58 % para los tratamientos con el máximo nivel de fertilizante a los 120, 180 y 240 días de la siembra. La adición de la cepa de rizobio utilizada como inoculante y la fertilización fosfatada constituyeron una estrategia favorable para incrementar la producción de alfalfa.

The objective of this work was to study the effect of the addition of polyphenolic peanut skin extracts (PSE) and oregano essential oil (OEO) on the microbiological, chemical, and sensory properties of frankfurter-type sausages during storage. Seven treatments were prepared: control sample (C: without additives); sausage with commercial additives (F); with OEO (O); with Runner PSE (R); with Virginia PSE (V); with OEO and Runner PSE (OR), and with OEO and Virginia PSE (OV). Consumer tests and general composition analysis were performed on the fresh products (sausages without storage). Sausages were stored at 4 °C during 37 days and samples were extracted at days 0, 12, 23, and 37 for microbiological, chemical (peroxide value and conjugated dienes), and sensory descriptive analysis. All sausages had low fat content (3.36 g/100g) and good colour, flavour and texture acceptance scores by consumers (between 57 on a 9-point hedonic scale). The absence of commercial additives (nitrite, nitrate, and other compounds) affected the sausage characteristic colour, reducing the consumer’s acceptance. The treatments with natural additives had less microbiological and chemical deterioration compared to control sample. The results suggest peanut skin extracts and oregano essential oil can replace commercial additives as preservatives in sausages.