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

It is an investigation that deals with the phenomenon of occupational stress and its most acute manifestation: Burnout Syndrome. The study was developed in Mexican high school professors. An investigation in Depth inquiry, was made through the phenomenological or interpretive paradigm, the qualitative approach, performed with a single case study method; the techniques used were life history, non-participant observation and interview, and as instruments: the questionnaire and field diary. The main results show an analysis of the problems of this syndrome through four main categories: work-related stress, the professor, the student and the institution. The first explains the essence of how the syndrome is perceived, the remaining three, outline the perception and experience of the problem of the professors and their activities; the student and what implies to share time to professors with this problem and, finally, the institution, in the sense of how it faces what lives inside of it as a result of having the existence of a teacher with these characteristics.

In this paper we analyzed the use of linear graphs in an engineering community in order to generate a significance base for the development of a functional mathematical reasoning. This research is based on the socioepistemological framework. We present three illustrative cases on how the scientific-academic community uses cartesians graphics. From these uses, meanings for mathematical knowledge are integrated into a richer and articulated greater significance on the notion of lineal slope and points of intersection. The objective is to show the possibility of a didactical change from objects to practices, proposal that can permeate along the school context as an educational tool for the development of mathematical reasoning.

El libro Miradas históricas a la formación del profesorado en Chihuahua nos permite realizar un recorrido histórico sobre la formación docente, adentrándonos en las políticas educativas, la formación docente e historia de instituciones y maestros ilustres. Esta reseña tiene la finalidad de exaltar las bondades de la obra e invitar a su lectura como requisito para conocer y entender de forma clara la realidad actual de la formación de los profesores en México, dando énfasis en el estado de Chihuahua. Se conjuntan 13 docentes investigadores que en nueve capítulos –y desde una mirada personal– nos ayudan a construir nuestra propia mirada.

The purpose of the following documentary research was to reflect about the importance and use of the portfolio of evidence as a mode of qualification in normal schools; this implies that the future teacher reflects and analyzes his formation and development of professional competences, by linking them with his teaching practices. The methodology used consisted in a documentary analysis, as well as the use of conceptual cartography to direct the work to be done. The results obtained allowed to identify the idea of portfolio of evidence from the social-formative approach as a process that joints didactic with assessment, and is focused on talent development from the continuous improvement of evidence. It was possible to determine the following axes in the portfolio methodology: competences selection, evidence determination, evidence systematization, assessment, reflection and analysis, socialization and certification. It is suggested to validate the proposed methodology from the socio-formation and to develop an analytic rubric that enables the appraisal of student’s portfolios as a qualification modality in normal schools.

This research work was split into two experiments. The first evaluated the effect of nutrient omission on biomass accumulation and bromatological composition of perennial diploid ray grass (Lolium perenne) while the second assessed the effect of N rate application (0, 70, 140, 210, 280, 350 and 420 kg N/ha/year) on biomass accumulation, bromatological composition and N use efficiency of the same cultivar. Omitted nutrients were N, P, K, Mg and S. Statistically significant differences (p>0.05) were found for biomass production (kg DM/ha/cut) and protein content (%) with N omission, while the omission of P, K and Mg only affected biomass production, but not the bromatological composition. The omission of S did not affect either biomass productionor bromatological composition. Nitrogen application increased biomass production and protein content with the increment in N rates. The DM data in response to the application of N rates were utilized to calculate AEN which in the case of the studied ray grass was of 14 kg DM/kg of applied N. With this information and the implementation of N omission plots the N rate necessary for the following crop cycle can be predicted. A GreenSeeker was used as a tool to obtain NDVI data which confirmed the effect of N in the accumulation of DM and AEN. Finally, the cost to produce one kg of ray grass biomass decreases with the increment of N rates. It was demonstrated that the production costs vary from 0.05 to 0.06 dollars/kg DM with the N rates ≥ 140 kg/ha/year, in comparison with the cost of one kg of concentrate which varies from 0.50 to 0.60 dollars per unit weight.

The objective of this study was to evaluate the agronomic performance of maize hybrids in three different localities in the Ecuadorian Coast. Five hybrids of maize: two local hybrids (INIAP H-551e INIAP H-601), two foreign hybrids (Insignia 105 and S-505) and one experimental material (UTEQ) were evaluated. We used a Complete Block Design with 5 treatments in 4 replications and Tukey tests at 95% probability to establish the differences between the means of the treatments. The main results indicated that the locality had no effect on the dependent variables under analysis. The experimental hybrid UTEQ had the shortest time to male flowering with 49.8 days, while the hybrid S-505 with 53.6 days had the longest. The INIAP H-551 hybrid had the shortest cobs, with an average of 15.5 cm, while the longest cobs were produced by the UTEQ hybrid. The S-505 hybrid had the cobs with the highest number grain rows (17.4), while the INIAP H-551 with an averageof 13.3, showed the lowest number of grain rows. The UTEQ hybrid had higher yields than those observed for the two INIAP hybrids, reaching an average yield of 6852 kg/ha, with the Insignia 105 and S-505 hybrids the most productive with yields of 8336.4 and 8151.6 kg / ha, respectively. In economic terms, the hybrid UTEQ, had a profitability of 75-81%, so that we conclude that this material should be promoted among small-scale producers, since it has low costs per unit of production.

This article analyzes the effect of 1-Meticlclclpropen on the inhibition of ethylene in babaco fruit (Vasconcellea x heilbornii var. Pentagona), with three ripe stages and three exposition times. A Complete Random Design with four repetitions was used. The variables under study were: loss of weight, fruit firmness, total concentration of soluble solids and percentage of titrated acidity. The lowest loss of weight was obtained for fruits harvested earlier (“Green”) and exposed to 1-Meticlciclpropen for a short period of time (7 days). In the case of fruit firmness, the best results were obtained when fruits were harvested “Green”. The total concentration of soluble solids was higher for fruits harvested in stages “Green-Yellow” and “Yellow”, while the values of titrated acidity increased with the fruit ripeness. The time of exposure to 1-Meticlclclpropen had no significant effect on fruit firmness, total concentration of soluble solids and percentage of titrated acidity.

The demand for broccoli has increased significantly in the last years due to the benefits of its consumption for human health. This poses new challenges for producers, who increasingly rely on technology to improve production processes, increase yields and thereby meet the current demand. One of the technology fields that has gained interest in crop production the use of Computer Vision models, which can provide support and assistance in food production. This paper proposes an algorithm based on color detection of broccoli, which, at the macro level can identify phytosanitary problems in broccoli plantations; and, at the micro level can be used to identify the product that is suitable for consumption. The algorithm uses open source tools such as OpenCV and Python, so that it can be developed at low cost with results similar or better than those obtained with commercial softwares.

From the analysis of several sources and the legal regulations in force, this paper addresses the situation of the Agricultural Mechanization as a professional field of action within the Agricultural Engineering, its characteristics and requirements in Ecuadorian conditions. The resulting analysis -written from a detailed literature review and discussion with experts within the field-, will be useful for the understanding of the role that the professionals within the field play in the management and administration of agricultural machinery, as well as in the learning process. Finally, it is concluded that the agricultural machinery management is an important field of action for the Agricultural Engineer, so that it demands training for the selection and planning, as well as in the estimation of costs and yields.

A study was conducted in two phases, one at the Experimental Station greenhouse and other at the Soil Testing Lab, both belonging to the College of Agriculture, Central University. The objective was to evaluate the effect lime amendments to control soil acidity on a soil representative from the red acid soils classified as Oxic Dystrudepts at the Loreto canton, Orellana province. Soil presented an initial 5.2 pH, and values of 0.52 cmolc kg-1 of exchangeable acidity (H+ + Al+3) and 0.39 cmolc kg-1 of exchangeable aluminum (Al+3). Four amendments (calcium carbonate, dolomite, calcium oxide and magnesium carbonate) and 8 lime rates (0, 1.0, 1.5, 2.9, 3.0, 4.0, 6.0 t ha-1) were evaluated. Treatments were replicated 3 times giving a total of 24 experimentalunits per amendment. The greenhouse experiment was started mixing the lime rates with 2 kg of soils and placing them in plastic pots which were kept at near field capacity for 45 days to allow complete reaction of the liming materials. After this time pots were seeded with wheat (Triticum vulgare) and were allowed to grow for 6 weeks. Above ground biomass was harvested to evaluate fresh and dry matter accumulation. Soils samples from the pots after harvest were used for the lab analysis determination of pH, H+ + Al+3 and Al+3. A complete randomized design was used for statistical evaluation. Greenhouse results indicated that the higher mean biomass yields of the indicator plant were obtained with the application of dolomite and calcium carbonate. It was also observed that the higher accumulation of biomass was obtained with amendment rates ranging from 1.0 to 1.5 t ha-1. Soil analysis demonstrated that pH values increased as lime rate increased, but the opposite was observed for H+ + Al+3 and Al+3, however, only the lower rates agreed with the rates that produced the higher yields. Graphic analysis of the pH with H+ and pH with Al+3 interactions showed the same tendencies. All this information documented the dynamics of the changes promoted by the addition of the amendments on biomass accumulation and soil properties and, in indirect form, the right rate of the amendment, but this information is not enough to deliver a rate recommendation fitted for every particular soil. It was proposed to use the method developed by Kamprath using the initial values of H+ + Al+3 to be plugged in the following formula: CaCO3 (t ha-1) = 2.0 x cmolc of + + Al+3 kg-1 of soil. When the numbers were plugged the result was CaCO3 (t ha-1) = 2.0 x 0.52 cmolc of H+ + Al+3 kg-1 of soil ≈ 1 t ha-1 CaCO3. This formula can then be used for all the acid soils with the same characteristics as the soil incubated at the greenhouse.