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Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant function analysis (DFA). It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001) and DFA (Wilks’s λ = 0.036, p < 0.01). PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1) and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2) also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant (p < 0.01) differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species.

Cytogenetic analysis of Trichomycterus areolatus, collected from the Tijeral and Huilma Rivers in southern Chile has shown a diploid chromosome number of 2n = 54, a fundamental number of FN = 106, and a karyotypic formula of 44m + 8sm + 2st. Intra-individual polymorphism of chromosome number (2n = 54, 55 and 56) in specimens from the Huilma River has also been documented, providing further evidence of the occurrence of this phenomenon in Trichomycterus. The karyotype exhibited large chromosome pairs: metacentric pairs 1 (relative length 7.54%), 2 (5.75%) and 3 (5.09%), submetacentric pair 23 (5.25%), and subtelocentic pair 27 (5.28%). Nuclear DNA content analysis showed an average value of 5.04 ± 1.09 pg/nucleus. This DNA content is higher than the mean value described for other species in this genus.

En el campo de la docencia se presenta a menudo un gran abismo entre teoría y práctica. Los docente en su mayoría consideran que la teoría y la investigación tienen muy poca la relación con su quehacer diario.El propósito de este trabajo es el de presentar algunas ideas acerca del rol del docente como investigador. Es del conocimiento de las autoras el temor y la preocupación que expresan lo maestros y profesores ante al posibilidad de realizar investigaciones sobre su trabajo en el aula.Según Riordan (citado en Nunan 1989), el docente en raras ocasiones tiene una participación activa en algún proyecto de investigación. Su conocimiento acerca de su trabajo generalmente no se aprecia o no se toma en cuenta como referencia para la realización de investigaciones con la participación de profesionales en este campo. Los resultados de investigaciones, por otro lado, algunas veces se presentan en un estilo que es comprensible solo para el investigador; no así para los docentes, padres de familia o personal administrativo. Este autor insiste en que los investigadores profesionales son los únicos qeu se benefician con los resultados de estas investigaciones, ya que ellos constituyen la audiencia principal de estas, no así el docente.

Una de las preocupaciones de los educadores hoy en día es proporcionar a los educandos un ambiente adecuado para que el proceso enseñanza aprendizaje sea eficaz y al mismo tiempo agradable. Existen variadas técnicas y estrategias que los docentes pueden utilizar en el aula como instrumentos metodológicos para lograr qeu este proceso se lleve a cabo.Una de las modalidades que se han utilizado, en medios ajenos al nuestro, es el "aprendizaje en cooperación". Se pueden encontrar diferentes estudios e investigaciones relacionadas con este tema. Como su nombre lo indica, se trata del trabajo escolar en grupos que se realiza en forma cooperativa. Artzt y Newman (1990, p.2) presenta la siguiente definción: "aprendizaje en cooperación involucra a pequeños grupos de estudiantes, que trabajan juntos en equipo para resolver un problema, completar una tarea, o alcanzar un objetivo común."

The study of communication strategies can provide insights into the ways in which interlanguage changes and develops as language learners become increasingly proficient in the target language. This article describes an investigation centered on the communication strategies used by two groups (intermediate and advanced) of Spanish-speaking students of English to express lexical meaning. Two different tasks, one conskting of answering structured questions and the other a simulated communication situation, were used to elicit data from the students. Data were collected at two different times, once at the beginning of the term and again five weeks later. Proficiency level, task, and time were the independent variables and three types of communication stmtegies (transfer, overgeneralization, and task-influenced) were the dependent variables. It was found that the unstructured task elicited significantly more transfer strategies from both groups of students, and that there was a significant interaction between time and proficiency level with respect to the use of task-influenced strategies—the advanced group used a greater mean proportion of task-influenced strategies than the intermediate group at Time1, while the intermediate group used a greater mean proportion of this type of strategy at Time2. A post hoc analysis of these data suggests that students of a language may go through a period of maximum exploitation of task-influenced strategies which peaks and then drops off as they become more proficient in the language.