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

This report is part of a larger investigation that was interested in characterizing the probabilistic thinking of children with disabilities. In particular, the document shows the use of compensatory schemes related to the probabilistic thinking of children with intellectual disabilities. Three guiding axes govern the research, qualitative and ongoing: epistemological, cognitive and social. Here are presented the results of the third phase that concerned the understanding of the fundamental ideas of probability, after teaching, of three young people [15-17 years old] with intellectual disability of the third degree of special secondary, revealed in semi-structured individual interviews in the Gesell camera on the frequency approach of probability. The strategy was to give students the role of examiner to obtain data of their understanding of the mathematical concepts included in what they examine. The results concern the use of working memory, the visual perceptual scheme and the attention for the ideas of sample space, probability measure and random variable (qualitatively with absolute frequencies).

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The Masa Stork Company recognized in the hydrocarbons sector in Colombia, in a power generation project saw the need to use 2-inch tubing to transport wastewater in the cooling of motor-generators, presenting the problem of fracture in the welding when they are put into operation. When stainless steels are heated in a temperature range of 500 ° C to 700 ° C, the carbon-containing the steel reacts with the chromium to form chromium carbides that do not have the same characteristics as the alloyed chromium. These reactions deplete the steel and reduce its properties in the heated zone. This investigation focused in the determination of the influence of the temperature in the ZAT of a welding in stainless steel AISI 316, under GTAW process, welded with ER316 electrode when subjected to pre-heating temperature before welding and its behavior before heat treatment; and determining that in the welding a low contribution of heat must be taken into account, distributing the heat in a balanced way so that it is distributed in the piece as symmetrically as possible. In addition, it must be ensured that the level of embrittlement is as low as possible, thus making the Zone Affected by heat more narrow.

Nitrogen compounds are being injected into the environment by human activities, which are altering the global nitrogen cycle and, thus, water systems. There is principally serious growing concern about the actual environmental consequences of the nitrogen pollutants in groundwater since a safe supply of clean water is needed for human consumption. Recent observations in the field of measurements and studies in the laboratory suggest that there are limitations of effective methods that detect and quantify biogeochemical reactions of nitrogen loss occurred in this aquatic body. This review explores our understanding of nitrogen pollutants on groundwater, taking into consideration the biogeochemical reactions of nitrogen cycle, and the limitations and advantages of analytical methods used in the detection of nitrogen compounds.

This article is part of the results of the research on the Educator in Colombia for Virtual Education from the analysis of the Information Society and Knowledge; the following study and structure on three moments of analysis on the breakthrough of Technology in the field of education; the first, investigates and traces the discursive practices that shape the Virtual Educator and how the virtual emerges in the history of Colombian education; in the second, we chose the archeological-genealogical method, methodological arsenal that distances itself from the transcendental conception of history, to make an analysis of the regimes that establish, normalize, naturalize and legitimize the permanent presence of Technology in Education in the discursive field of Virtuality. In the third moment, the results are presented and it is concluded from the discourses that show the power strategy of the Society of Information and Communication in education.

The densified of wood is a mechanism of deformation that occurs during the manufacture of composite products. This technology aims at the dimensional stabilization of wood and increases its mechanical properties. The objective of the research was to densify Gyrocarpus americanus Jacq. wood and to evaluate the effect of the treatment on density and modulus of elasticity. Initially, the wood was hydrated in water for 72 h and at a temperature of 20 °C. Subsequently, the specimens were softened for 4 h in hot water at a temperature of 93.5 °C. The specimens were then pressed with a device made especially for the investigation. The research strategy was to determine density and perform static flexion tests before and after treatment. The compression and densification coefficients were evaluated after treatment. Thirty-two standardized specimens were prepared and static flexural tests were performed before and after densification. For the before and after densified results tests of mean differences for independent samples were performed. The regressions between the values of the modulus of elasticity as a dependent variable were calculated as a function of the independent variable density. The compression coefficient was 56.3% and the densification coefficient was 50.3%. After treatment, the density of G. americanus increased 102% and its modulus of elasticity increased by 113%. The densified, elastic and quality indices confirmed that the densified hygrothermo- mechanical treatment produced good results for low-density wood.

The evaluation of student behavior in the development of their professional activities represents an important element to measure their academic performance. At the Central University Martha Abreu de las Villas, professional practices are implemented at distances through a system of remote laboratories. However, there are no procedures to mediate professional skills. The present investigation describes a solution to the problematic raised from the development of a model for the evaluation of professional abilities for the systemof remote laboratories. The proposed model uses a multiexpert multicriteria approach with the use of a diffuse cognitive map to represent causal knowledge. Two experiments are applied to test the impact of the proposal using the Wilconxon signed nonparametric range test. It was obtained as a result of the first experiment that there is a significant statistical difference of the access control inferred by the model with respect to the total of people who developed the laboratory practices; In the second experiment it was found that there is no significant statistical difference in access control inferred by the model with respect to the successful development of laboratory practices. The results corroborate that its application guarantees the diagnosis of professional skills for access control of laboratory practices in the system of remote laboratories.

In this paper, some ideas are presented on the aspects that need to be considered in the planning, design, implementation and evaluation of a didactic unit. The importance of understanding the elements that constitute it and its articulation with the objectives, resources, and activities proposed in its development are emphasized. In addition, it is intended to highlight how relevant is the exercise of planning, design and evaluation done by teachers, as a space for reflection, reconstruction, and qualification of their teaching practice. An important contribution is the one related to the curriculum design map, which, since our point of view, is fundamental when it comes to guiding the teaching and learning processes. Some reflections on the importance of the development of cognitive-linguistic skills and the use of new technologies in the design, development, and evaluation of didactic units are also presented.