Abstract - Revista CDT Nº 26

Abstracts - CDT Nº 26
		Humanities and Social Sciencies
Research	[Index] - [Spanish]

Modalities of Educational Tutorship in Solving Problems and in Knowledge Learning

N. D. Roselli*

Key-Words: : tutorship modality - didactic model - knowledge teaching - Instruction Psychology - Constructivism

The research aimed at comparing three modalities of educational tutorship: one centered on the teacher ("expositional"), another one on teacher-student interaction ("participative"), and a third one on interaction among students themselves ("do-without"), in order to analyze the differential learning effects. In the first modality, the activity is almost exclusively in charge of the expert-teacher. In the second one, the development of the class is interactive between teacher and students; the former motivates and guides the input by the latter. The third modality is related to a knowledge construction model achieved exclusively among peers, the teacher merely being in charge of organizing the exchange. The design was a pre-test/post-test experimental type, divided in two parts: one with secondary school students and another one with university students. The teaching stage was carried out with groups of 5 to 6 students. The evaluation of the learning achieved included the clinical questioning of the subjects. The data obtained were quite similar in both student groups. It was concluded that no modality was more effective than the others in absolute terms. The type of contents (logical problems and scientific knowledge) and the level of initial aptitude of the subjects are significant intervening variables.

*Director del Instituto Rosario de Investigaciones en Ciencias de la Educación IRICE-CONICET, Argentina. Profesor de la Facultad de Ciencias de la Educación, Universidad Nacional de Entre Ríos (UNER), Argentina. E-mail: roselli@ifir.ifir.edu.ar

Construction of the Knowledge to Be Taught in the Geography, History and Philosophy, Psychology and Pedagogy Teachers College

M. E. Saleme de Burnichon*, M. del C. Castells**, M. A. Migueles, M. l. Corfield

Key-Words: Didactics - knowledge to be taught - construction - teachers' education

In this research a modified reproduction of a previous research was made. Five general hypotheses This research dealt with Didactics teaching, a field considered relevant and not explored enough in that discipline configuration. The Hugo Zemelman proposal was chosen as epistemologic-methodologic perspective. In spite of taking as a starting point the Didactic Transposition theory and its idea of knowledge to be taught as a basic ordering concept, the problematizing movements lead to the specification of concepts related to Didactic Knowledge. The idea arose that the teachers, while preparing the knowledge to be taught, pose a particular form of construction that implies the creation of a new knowledge, which in turn is a product of relationships with subjects, knowledge domains and experiences. The problem has aimed at deciphering the meanings and mechanisms that order such process in the courses of the Didactic Area in different Teachers Colleges, thus understanding that this aspect, overlooked in Teachers Colleges, must constitute a central question.

*) Directora del Centro de Investigación, Fac. Filosofía y Humanidades, Universidad Nacional de Córdoba (UNC), Argentina. E-mail: maburni@cifyfh.edu.ar
**) Codirectora, Profesora Fac. de Ciencias de Educación, Universidad Nacional de Entre Ríos, (UNER), Argentina E-mail: castells@fiqus.unl.edu.ar

An Approach to the Operation of the Flower Market in the Province of Entre Ríos (Argentina)

G. F. Villanova*, G. Dondo, M. Handloser, M. Schoenfeld

Key-Words: Economy - floriculture - supply - demand - non-traditional option

The research presented was aimed to generate information about productive and commercial possibilities of floriculture in the Province of Entre Ríos and to verify whether the obstacles to such activity’s development lay in the market. It was focussed on the characteristics of the supply and demand for flowers in the cities of Paraná and Concepción del Uruguay in a first stage. The absence of commercial producers of flowers in Entre Ríos was determined and wholesale distribution channels from which the local retailers obtain their supply were identified. The characteristics of the cut flowers supply were defined. An important aspect of the results is the characterization of the supply, since the information obtained allows understanding the motivations of consumers, the species in demand along the year, variations according to income and possibilities of future expansion. It was corroborated that floriculture constitutes a productive option but the market access presents obstacles difficult to overcome successfully by small individual producers.

*) Profesor Facultad de Ciencias Agropecuarias, Universidad Nacional de Entre Ríos (UNER), Argentina. E-mail: villanovagafer@arnet.com.ar

Science and Society: Epistemological Contributions to Reinstate a Dissociated Link

G. Pizzio*

Key-Words: science - society - dissociation

To consider the social domain as a universe constituted by the juxtaposition of multiple fields of relative autonomy, among them the scientific one, could contribute to understand the current process of disintegration of the link between science and society. In this essay, we review this process historically by focusing in the epistemological problem of "science - no science" and "science - sciences" delimitation. It is also proposed that the increase in the specificity, specialty and autonomy levels of science is correlative to its progressive segregation. It is stated that science, as a product of social collaboration processes, cannot continue being the patrimony of a few; therefore the authority to define new criteria for delimitation must be shared with other fields in a solidary way.

*) Lic. en Comunicación Social, Facultad de Cs. de la Educación,Universidad Naciona de Entre Ríos (UNER), Argentina. E-mail: gustavopizzio@hotmail.com

Technical and Natural Sciencies, Ingeneering and Technology

Design of an Electromyographic Equipment Based on a PC

Monica Baroli, Claudia Bonell*

Key Words: electromyography - muscle fiber - motor unit - motor unit potential

The electromyography (EMG) records signals originated in muscles when the train of impulses generated from motor nerves decrease. The width of the EMG signal is of a stochastic nature and can be reasonably represented by a Gaussian distribution function. The signal width ranges from 0 to 6mV (peak-to-peak) or from 0 to 1.5mV (mean quadratic value) and the spectrum of the useful signal (the one where its energy is higher than the noise level) is mostly limited from 0 to 500Hz, being dominant in the range 50-150Hz. This signal, after being acquired and conveniently processed, is widely used in clinics as a tool for diagnosis for numerous pathologies of the central and peripheral nervous systems and neuromotor and muscular systems. The equipment designed and implemented has an acquisition channel for the electromyographic signal, connected to a personal computer for acquisition and later processing. The adquired and processed signal can be employed conventionally for clinical applications or used for mathematical study or biofeedback if access to signal recordings is granted.

* Laboratorio de Ingeniería de Rehabilitación e Investigaciones Neuromusculares y Sensoriales (LIRINS), Facultad de Ingeniería, Universidad Nacional de Entre Ríos (UNER), Argentina. E-mail: mbaroli@yahoo.com

Agricultural and Medical Sciencies

Bioecology of Watergrass (Echinochloa spp.) in Rice Fields Under Different Management Techniques in Entre Ríos (Argentina)

R.A. Sabattini*, S.M. Sione, M.M. Anglada, A.F. Dorsch, J.I. Elizalde, V.H. Lallana, A. Maidana,
A. Del Porto, S. Ledesma, G. Cencig

Key Words: Echinochloa - watergrass - rice - Bioecology - Entre Ríos

This research aimed at assessing the incidence of watergrass under the management techniques for rice cultivation, and the use of herbicides as the most effective method for control in the Central Area of Entre Ríos. The incidence of watergrass species was verified in rice cultivation according to the management techniques used through the study of its seeds, germination conditions, composition of seed bank, seedling emergence, watergrass phenological behavior, life expectancy and use of cultivars to prove its competitive ability. The three agricultural cycles assessed (1997/98, 1998/99 and 1999/00) allowed to confirm the significance of chemical control as a priority management guideline to achieve convenient rice yields, while significant differences were not detected between the different chemical treatments assessed. It was also concluded that the history of the allotment and rotations have an important role in watergrass population installing and weeds in general, and that the selection of cultivars with high competitive ability constitutes a useful technique to diminish the effect of cultivation-weeds competition.

*Facultad de Ciencias Agropecuarias, Universidad Nacional de Entre Ríos (UNER), Argentina. E-mail: rsabatti@fca.uner.edu.ar

Viability and Longevity of Forage Legume Hard Seeds

L. R. Zimmermann*, A. A. Galussi, A. H. M. Martinelli, A. P. Fernández

Key Words: viability - Tetrazolium - longevity - hard seeds - forage legumes

The objectives of this work were to assess viability and longevity of hard seeds of Medicago sativa L., Lotus corniculatus L., Trifolium pratense L., Trifolium repens L. and Melilotus alba Med. In a first stage, the proportion of viable hard seeds was quantified in 50 allotments recently cropped. Then, viability was assessed through the hard seeds time from 10 allotments of each species, stored under different temperature and humidity conditions. In order to evaluate viability Topographic Analysis with Tetrazolium was used. In general, the initial viability percentages of the allotments were high in the species studied. However, responses to time and conservation conditions were different according to the species. Since there was no evidence found to support a 100% of viable hard seeds, as it is established by the curren Argentine legislation, the Topographic Analysis with Tetrazolium is suggested for the hard seeds found in the Germination Analysis.