Humans settled the Caribbean ~6,000 years ago, with ceramic use and intensified agriculture marking a shift from the Archaic to the Ceramic Age ~2,500 years ago 1 – 3 . We report genome-wide data from 174 individuals from The Bahamas, Hispaniola, Puerto Rico, Curaçao, and Venezuela co-analyzed with published data. Archaic Age Caribbean people derive from a deeply divergent population closest to Central and northern South Americans; contrary to previous work 4 , we find no support for ancestry contributed by a population related to North Americans. Archaic lineages were >98% replaced by a genetically homogeneous ceramic-using population related to Arawak-speakers from northeast South America who moved through the Lesser Antilles and into the Greater Antilles at least 1,700 years ago, introducing ancestry that is still present. Ancient Caribbean people avoided close kin unions despite limited mate pools reflecting small effective population sizes which we estimate to be a minimum of Ne=500–1500 and a maximum of Ne=1530–8150 on the combined islands of Puerto Rico and Hispaniola in the dozens of generations before the analyzed individuals lived. Census sizes are unlikely to be more than ten-fold larger than effective population sizes, so previous estimates of hundreds of thousands of people are too large 5 – 6 . Confirming a small, interconnected Ceramic Age population 7 , we detect 19 pairs of cross-island cousins, close relatives ~75 kilometers apart in Hispaniola, and low genetic differentiation across islands. Genetic continuity across transitions in pottery styles reveals that cultural changes during the Ceramic Age were not driven by migration of genetically-differentiated groups from the mainland but instead reflected interactions within an interconnected Caribbean world 1 , 8 .

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Palavras chaveEstilística educativa, estilo cognitivo, estilo de aprendizagem, estilo de ensino, pesquisa. Palabras ClaveEstilística educativa, estilo cognitivo, estilo de aprendizaje, estilo de enseñanza, investigación. ResumenEl artículo es una revisión teórica que explora el potencial de la estilística educativa, como campo de investigación, desde dos perspectivas: 1) con el análisis de la presencia del concepto de estilo como tema o problema de investigación educativa en los últimos años en el ámbito latinoamericano, y 2) mediante la identificación de las líneas de investigación educativa relacionada con el concepto de estilo que poseen mayor proyección futura en la región. En el primer caso, se presentan los resultados de un estudio bibliométrico realizado a partir de bases de datos de alcance regional. Para el segundo, se proponen reseñas temáticas que destacan la dirección de la investigación sobre estilos en las cuatro áreas que poseen mayor desarrollo reciente: los entornos virtuales o a distancia, los estilos de enseñanza (docencia), el examen de intervenciones educativas y la discapacidad.

This study is expected to determine the impact of a program based on the cooperative learning methodology. This, in comparison to a traditional learning situation in both mathematics and language achievement. The study was carried out on a group of fourth grade students of primary school. In addition, it tried to find the differential impact according to the cognitive style in the field dependence-independence dimension. This work was carried out with 76 students of the Colegio José Martí I.E.D. (Bogotá-Colombia) ranging from 8-12 years of age. The control group received a traditional teaching methodology and the experimental group received the cooperative learning program, composed of 35 sessions (from July to November 2009). All the participants were tested in mathematics and language performance, before and after the intervention. All of them were tested in cognitive style as well. The results suggested that the cooperative learning methodology benefited importantly the academic achievement of the students in mathematics in contrast to the competitive and individualist situations. The results also suggested that the three cognitive style groups were positively affected from the cooperative learning situation. These results were not found in the language area.

ResumenEl presente artículo explora algunos de los factores que explican el desempeño escolar. Para ello se identificaron y caracterizaron perfiles de estudiantes chilenos de octavo grado de primaria (media 13.65 años de edad/DS 0.74), en función de su desempeño académico en la prueba de Historia, Geografía y Ciencias Sociales, y variables de contexto. La base de datos fue generada por el Sistema de Medición de la Calidad de la Educación de Chile (Simce). La investigación se orientó desde el enfoque cuantitativo correlacional predictivo, utilizando el árbol de clasificación y regresión (cart). Las altas expectativas educacionales de la familia son el factor diferenciador más importante en el rendimiento escolar. Se discuten los resultados en función de la investigación y literatura generada acerca de estos temas. AbstractThis study explored some of the factors that explain school performance. To attain this, Chilean students' profiles of eighth year of primary school were identified and characterized (13.65 year old mean/DS 0.74). This was done according to their academic performance in the History, Geography and Social Sciences test, and the context variables. The database was provided by the Sistema de Medición de la Calidad de la Educación de Chile (Simce). The study was conducted by means of a predictive correlational quantitative design, using a classification and regression tree (cart). Parents' high educational expectations are the most important distinguishing factor in school performance. The results are discussed in relation to previous research about these topics.Palabras clave: desempeño escolar, escuela primaria, rol de la familia, expectativas educacionales de la familia, análisis de regresión, perfiles de estudiantes, cart.