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

A review of the current state of organic light-emitting devices (OLED) is presented, with an emphasis on those that emit in the red band. To understand the operation of this type of device, the different architectures used and the emission mechanisms of these optoelectronic devices by fluorescent and phosphorescent radiation are shown. For the case of red emitters, examples with the two most commonly used types of materials are presented: DJCTB for fluorescence and Ir(piq)2(acac) for phosphorescence. Although the architectures and mechanisms herein reviewed apply to red emitters, they can also be extended to emitters throughout the visible range.

Parasitic diseases are considered to be one of the most prevalent pathologies worldwide. They are characterized as one of the most critical sanitary problems in cattle, causing a decrease in the productive capacity of parasitized animals, which translates into economic losses. Intestinal parasitism in cattle is caused by protozoa and helminths, and its manifestation is generally multi-etiological. Clinical signs in gastrointestinal parasitism may vary depending on parasite load, parasite species, and host immunity. This research aimed to determine the prevalence of the main parasitic families affecting cattle in the central province of the department of Boyacá. A cross-sectional study with simple random sampling was carried out, where 716 fecal samples were taken and processed using a modified Ritchie technique. An overall prevalence of 95,6% was determined, and the most prevalent families were Trichostrongylidae, Eimeriidae, Taeniidae, and Trichuridae. The age showed no significant statistical association with most of the parasitic families, except for the Strongyloididae family. The breeds showed a correlation with the Trichostrongylidae, Eimeriidae, Strongylidae, Chabertiidae, and Taeniidae families. The results show the high prevalence of GIP (gastrointestinal parasites) in cattle of the central province of the department of Boyacá.

The objective of this research is to design and implement a methodological strategy based on directed research to develop laboratory practices by using daily products within the organic chemistry course of the Academic Graduate Program in Natural Sciences (PALCN) from Universidad Tecnológica del Chocó. To fulfill this objective, we began with a diagnosis of the laboratory activities in said subject. This study was founded upon a mixed approach by means of a case study design. Theoretical, empirical, and statistical methods were used. The results obtained showed that, during the 2019-2 academic period, he teachers that make up the study sample did not conduct any laboratory practices and, when they guided laboratory activities, these were experiences, illustrative experiments, and practical exercises. As for the methodological strategy, the student and the group of experts expressed that the construction of school knowledge is favored from research by the contextualization of science, whose dynamic process makes it easier for them to understand and apply concepts, as well as to develop skills and positive attitudes towards chemistry from a research problem. Based on directed research, this methodological strategy allowed rethinking organic chemistry laboratory practices, encouraging an active role in the students and turning them into main actors within their education process.

The objective of this work was to conduct a review on the use of artificial intelligence (AI) techniques applied to the formulation of public policies that contribute to the agricultural vocation of the regions. To this effect, a descriptive methodology with a mixed approach was employed. The methodological design used was PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The analyzed publications were taken from the Scopus database. For the quantitative analysis, the VosViewer software and the Bibliometrix R language library were used. As a result, it was found that AI techniques are employed to identify areas with an agricultural vocation or to find better agricultural practices that promote sustainable development. It was concluded that this research area is incipient and that it is necessary to generate new models that are more robust and include demographic, social, environmental, economic, and political variables.

This work presents applications of the Backward Seismic Analysis (BSA) method for steel storage tanks using a data base of more than 382 steel storage tanks in operation during large subductive earthquakes: Valdivia 1960, Central Chile 1985, Tocopilla 2007, El Maule 2010, Alaska 1964, and others in the United States between 1933 and 1995 (subductive and cortical). It has been recorded that most of the steel storage tanks without anchor systems have failed during large earthquakes. These have been designed with the standards API 650-E, AWWA-D100, and NZSEE, which propose similar procedures for estimating seismic forces, but with different design methods. During different conferences, the causes of the failures were evaluated, concluding that the tanks were designed mainly with the API 650-E code and were unanchored. Moreover, the design codes employed do not consider relevant aspects that condition the seismic response of steel storage tanks. This work develops a prediction model based on the historical information already described, which is capable of efficiently predicting if a steel storage tank will suffer any failures during an earthquake. Various algorithms were evaluated, finding that the Random Forest method exhibits the best results. The results obtained in the prediction of steel storage tank failures reach more than 90% efficiency in most of the evaluated scenarios.

Due to competitive markets, the software business wants faster, better, and cheaper solutions in a short amount of time. Software reuse emerges as a viable solution to these demands since it offers significant benefits, such as increased quality and efficiency and lower development costs and effort, as well as shorter commercialization times. This research aims to study and understand the state of the practice of software reuse in Colombia, to make comparisons with related works, and to offer an instrument for decision-making in companies that adopt these practices. To reach these objectives, three stages were proposed. In the first stage, the research questions were defined. In the second stage, a survey was developed, evaluated, and carried out to validate successful practices and adoption barriers in the context of the Colombian software industry. Finally, the results were analyzed and reported. This paper showed and evidenced the expectations, adoption barriers, and factors influencing the success of software reuse in Colombian industrial environments. In the same way, the experience from the development of this work serves as a roadmap for other regions that want to analyze the current state of reuse. Nevertheless, each organization needs to determine its capabilities and find the appropriate factors to be adopted to its context.

The decision to dismiss an employee on disciplinary grounds, following his reckless behaviour that exposed his workmates to the COVID-19 virus, is ruled as lawful by the analysed judgment which overturned the lower’s Tribunal decision for this purpose. The case details and its decisions are addressed in this comment, concluding it complies with the law, the opinion of the experts and the jurisprudence.

From a critical perspective of elements that integrate immigrants’ legal status in Chile, we analyze its legal foundation from the configuration of the rights and freedoms generated by the freedom of transit contained in article 19 Nº 7 a), of the Constitution. A study of the doctrinal constructions and the guarantees of a constitutional nature to protect this freedom is carried, allowing a diagnosis of the main decisions of the superior courts of justice which have had a shaping view of the legal status of immigrants, in disagreement with the decisions of the Immigration and Foreign Affairs Department.

This article aims to propose a control of suitability of intended parents, the elimination of anonymity in the donation of gametes and the determination of maternity by the fact of childbirth as paradigms of reconciliation between the best interests of the child and the intention of one or more adults to procreate. The proposal reacts to an assessment of the legal effects of assisted reproductive technologies on Filiation Law from the point of view of the best interest of the child. It criticizes the normative development that tends to validate the intention to procreate as a means of determination of filiation bonds. The issue is evaluated in aspects such as the access of single women to assisted reproductive technologies, the determination of paternity based upon the intention to procreate, double maternity and double paternity.