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

This paper summarizes and evaluates the article by Tonni and Politis (1980) on the distribution of guanaco in the province of Buenos Aires. The publication of this article is contextualized within the career of Eduardo P. Tonni. The integration of different lines of evidence: archaeological, paleontological, and paleoenvironmental are discussed. The data presented by different authors who tested the model are discussed, and the new topics generated from its discussion are presented. Among these new topics is the discussion about the presence of llamas on the banks of the Paraná River and the evaluation of dating on bone collagen taking into account its possibilities of contamination with more recent organic matter. It is concluded that after forty years of its proposal, the guanaco distribution model in the province of Buenos Aires has had remarkable vitality and has generated a debate that is still in force. In general, the model shows some trends that have been consolidated with the evidence generated since its proposal.

We describe Lutreolina tonnii sp. nov. (Mammalia, Metatheria, Marsupialia, Didelphimorphia, Didelphidae), recovered from Early (or Early–Middle) Pleistocene deposits of the coastal cliffs near Necochea City in Buenos Aires Province, Argentina. Its holotype, a right maxillary with M1-3, indicates that it belongs to the largest species of the genus, including extinct and extant species. It also differs from other species of the genus in having more anteroposteriorly compressed protocones in the upper molars. It differs from the living species in that the maxillary-jugal contact is less horizontal in its posterior two-thirds, has a deeper ectoflexus in M3, and has a shallow but distinct internal (lingual) crest linking the bases of stylar cusps B and D in M1-3. The new species is the fourth known up to now for the South American record, and the third for the Plio–Pleistocene of the Pampean Region, thus suggesting a considerable diversity for this genus in mid-latitudes of this continent by the end of the Cenozoic Era.

Trace elements, particularly rare earth elements (REE), are widely used as proxies to reconstruct paleoenvironmental and taphonomic conditions. We traced these elements in fossil penguin bones collected along the Paleogene sequence exposed in Seymour Island (=Isla Marambio) to test them as indicators of the tectonic changes to which this region was exposed. The results indicated the contents of REE in thirteen samples of the analyzed bone tissues. The negative europium anomaly in the samples from Bartonian and Priabonian beds reflects regional events. This signal coincides in time with the opening of the Drake Passage, and with the tectonic changes that occurred between the end of the Eocene and the beginning of the Oligocene, between the western margin of South America and the Antarctic Peninsula.

Species of the cellariid genus Melicerita Milne Edwards develop bilaminar flattened colonies consisting of alternate transverse rows of hexagonal zooids. In South America, its stratigraphic range extends from the early Miocene to the Recent. Re-examination of the type material of M. triforis Ortmann from the Monte León Formation at Río Chalía, and scanning electron microscope images of M. ortmanni Canu from the early Miocene Chenque Formation, confirmed that the latter is a junior synonym of M. triforis. Vicarious avicularia are described for the first time in M. triforis. Lectotypes are herein chosen for both nominal species. M. imperforata sp. nov. is described from material obtained in Monte León Formation (early Miocene). It differs from all known Melicerita species in the size and shape of its vicarious avicularia, which are marginal and much larger than the autozooids. The Recent Magellanic species M. temaukeli Moyano and M. blancoae López Gappa share morphological similarities with M. triforis.

EDITORIAL

Continuous teacher training is a constant need in any educational system, public or private. This article presents a systematized bibliographic review carried out under the Systematized Reviews in Human and Social Sciences Framework, with the objective of establishing the modalities, theories and educational methodologies, as well as the instructional design in distance education that can contribute to improve the design of a continuous training model based on virtual learning environments, using technology adaptable to the particular needs of the study context. Scientific documents published from 2004 to date are analyzed through hermeneutics, considering the conceptualization and characteristics of these forms of work, obtained from six different databases (SciELO, Dialnet, Web of Science, Redined, Redalyc and Google Scholar), formal institutions' web pages and some institutional repositories. The results show that it is possible to design a continuous training model based on virtual learning environments with forms of work in line with distance education, such as e-Learning, u-Learning, NOOCs, andragogical mediation, constructivism, socioconstructivism and connectivism, problem-based learning, and ADDIE methodology adapted to the web for the development of competencies.

The aim of this study was to analyze the effectiveness of an instructional intervention in the development of metacognitive skills of high school students at risk of dropping out of school. The study followed a quantitative approach in two phases. In the first phase, a model was validated to predict dropout through the risk of failure, and students at risk were identified. In the second phase, the intervention was carried out using a quasi-experimental design. We worked in an instructional way following the informed training model. The results suggest that it is possible to predict students who are at risk of failure and desertion from individual and contextual psychosocial variables. It was found that metacognitive skills influence the independent performance of contextual elements, that students with low performance have a low use of metacognitive skills. At the end of the intervention all dimensions of metacognition registered modifications, except for the knowledge of the strategies. This could be explained because it was the most developed dimension before starting the process, laying the foundations for the increase in the use of these skills that was appreciated in the study.

El trabajo de Luz Montes presenta una estructura construida lógicamente y se divide en dos secciones. La primera se intitula “Tipos de proyectos universitarios según la intención”, con los capítulos “I. Intención: acción sobre un objeto en un contexto”, “II. Tipos de proyectos” y “III. Expresión de un proyecto como texto argumentativo”. La segunda se llama “Esquema general para la formulación de proyectos”, y está integrada con los apartados “IV. Estrategias para la conceptualización: primera versión del protocolo”, “V. Confirmación: estrategias para ampliar el protocolo” y “VI. Estrategias para la construcción de un anteproyecto”. Como márgenes de estas partes se presentan, al inicio, una introducción y un reconocimiento al trabajo de Javier Nava González, mientras que el cierre incluye, además de las referencias tradicionales en todo trabajo académico, un epílogo y un apéndice. Esto hace del documento señalado un ejercicio didáctico pensado en el lector, quien también podría ser considerado como un usuario, pues el objetivo del libro de Montes es justamente ese: ser usado.

This study pursued three objectives, the first of which was to compare the working memory capacity in the verbal and visuospatial domains between students from two rural communities in the distance learning modality. The second was to compare fluid intelligence between both groups, and the third was to compare the working memory scores of both communities with those obtained by an urban community with similar characteristics. Following a quantitative approach, a descriptive study was carried out with 33 university students in each group, of whom 45% were women with an average age of 20.9 years and 20.6 years in men. To measure working memory, complex span tasks were applied with stimuli from the verbal and visuospatial domains. To measure fluid intelligence, the Raven’s Progressive Matrices test general scale was applied. In both measurements, the scores were similar between both rural communities and in the comparison with the urban community, for the latter, higher scores were found in the tasks of the visuospatial domain. This suggests that the context of the students may have played an important role in the measurements obtained, according to similar previous works.