Abstract This article shows a qualitative study on formative practices of internship tutors in seven pedagogy programs from the School of Pedagogy of a private Chilean university that belongs to the Council of Deans of Chilean Universities (CRUCH). Representations of tutors and interns about the role of the former and the pedagogic strategies they implement are analyzed in an inductive way, considering theoretical points of view from the constructivist and directive approaches. The data was collected from interviews carried out after watching a video record of their tutoring sessions, and shows a tendency towards educational support instead of the bureaucratic role present in the literature. The results show difficulties in the conceptualization of strategies, and the coexistence of and appreciation for both directive and constructivist strategies. The tutors’ discourse shows a prevalence of constructivist strategies, although internship reports and suggestions for improvement indicate a predominance of directive strategies. The strategy most valued by tutors are questions, while interns demand more directions.

Resumen Este artículo presenta un estudio cualitativo sobre prácticas formativas de tutores de prácticas profesionales en siete carreras de pedagogía de una universidad chilena privada perteneciente al Consejo de Rectores (CRUCH). Se analizan inductivamente las representaciones de tutores y practicantes, respecto al rol de los primeros y las estrategias pedagógicas que implementan, considerando aproximaciones teóricas desde los enfoques directivo y constructivista. Los datos -provenientes de entrevistas tras la observación de un video de su tutoría- evidencian en el rol un tránsito hacia el acompañamiento pedagógico, a diferencia del rol burocrático presente en la literatura. También se develan dificultades para tematizar las estrategias, así como coexistencia y valoración de estrategias directivas y constructivistas. En el discurso de los tutores prevalecen estrategias constructivistas, aunque el reporte de prácticas y sugerencias muestra predominio de estrategias directivas. Las estrategias más valoradas por los tutores son las preguntas, mientras los practicantes demandan incrementar la directividad.

Nous abordons l'étude de la variété des stratégies cognitives, idiosyncratiques ou apprises, utilisées par des étudiants du premier cycle d'école primaire au Chili, pour la pratique du calcul mental. Nous présentons une analyse des performances sur des tâches de calcul mental additif (addition et soustraction) d'un échantillon d'élèves d'écoles subventionnées dans des couches à milieu socio-économique faible et moyen dans les villes de Santiago et Valparaiso. Nous présentons un registre des stratégies détectées et une première version d'un logiciel développé par nous et disponible sur internet qui nous permet d'évaluer la performance des élèves, temps de réponse compris. Nous avons aussi étudié la corrélation entre la performance sur les tâches proposées (pourcentages de réponses correctes, temps de réponse) et le rendement scolaire moyen en mathématiques.

Focalizamos no estudo da variedade de estratégias cognitivas, idiossincráticas ou aprendidas, utilizadas pelos alunos no primeiro ciclo do ensino básico no Chile para a pratica de atividades de cálculo mental. Nós apresentamos uma análise do desempenho em tarefas de cálculo mental aditivo (adição e subtração) de uma amostra de estudantes em escolas de nível socioeconômico médio e médio-baixo subsidiadas pelo estado nas cidades de Santiago e Valparaíso, com um registo das estratégias detectadas e uma primeira versão de um programa desenvolvido por nós, disponivel na internet, para avaliar o desempenho dos alunos, incluindo seus tempos de resposta. Nós investigamos ainda a correlação entre o desempenho nas tarefas propostas (porcentagem de repostas corretas, tempos de resposta) e o desempenho escolar médio em matemática.

We focus on the study of the variety of cognitive strategies, either idiosyncratic or learned, used by students in the first cycle of elementary education in Chile to practice activities of mental calculation. We present an analysis of performance in additive mental calculation tasks (addition and subtraction) of a sample of students from state-subsidized schools in middle and low-middle socioeconomic strata in the cities of Santiago and Valparaiso. We construct a catalogue of the strategies detected and a first version of a software developed by us and available in the internet, which enables us to assess the student's performance, including their response times. We also analyze the correlation between the performance in the proposed tasks (percentage of correct answers and response times) and the average school achievement in mathematics.

Abordamos el estudio de la variedad de estrategias cognitivas, idiosincrásicas o aprendidas, empleadas por alumnos del primer ciclo de la enseñanza básica chilena al practicar actividades de cálculo mental. Presentamos un diagnóstico del desempeño en tareas de cálculo mental aditivo (sumas y restas) de una muestra de alumnos de escuelas subvencionadas por el Estado, en estratos socio-económicos medios y medio-bajos en las ciudades de Santiago y Valparaíso, junto con un catastro de las estrategias observadas, así como una primera versión de un programa desarrollado por nosotros disponible en internet, que permite evaluar el desempeño de los alumnos, incluyendo sus tiempos de respuesta. Analizamos además la correlación entre el desempeño en las tareas propuestas (porcentaje de aciertos y tiempos de respuesta) y el rendimiento escolar promedio en matemáticas.

To identify wild hosts of Trypanosoma cruzi, surveys were conducted in the subandean valleys of Jujuy Province, Argentina, between June 1986 and March 1987. Seventy two mammals from 13 different species were examined by xenodiagnosis. Fifty two of them were mostly roedents trapped at the localities of Maimará, León and Tilcara, and the remainder had been kept in captivity at the Estación Biológica Experimental, in Jujuy. Trypanosoma cruzi infection was detected only in 2 Octodontomys gliroides (2 pos./8 exam. 25%) from all 72 examined mammals. Isolates were called Octodontomys Argentina 1 and 2 (OA1 and OA2). Both infected animals were caught at the archaelogical ruin of Pucará, at Tilcara. Repeated searches for triatomines in the ruin itself and in neighbour houses rendered negative results. Groups of mice inoculated with either OA1 or OA2 isolates became infected between 7 (OA1) to 12 days (OA2) postinoculation PI. Parasitemia peaks were observed between day 12th - 14th PI. Scarce amastigote nests were found in myocardium and skeletal muscle. Mortality was observed only for mice inoculated with OA1. Isoenzyme patterns of OA1 and OA2 were identical to one found in dogs and slightly different from that of human parasites in Argentina. Bones from Octodontomys sp., were recently found in a cave, dated 10200-8600 BC, in Pumamarca, near Tilcara, Jujuy. There are evidences that O. gliroides cohabited with man in ancient times and was associated to the domestic cycle of T. cruzi transmission, playing a role like that of domestic cavies. in Bolivia.