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

The main purpose of the present research is to solve the sequencing problem with earliness penalties and quadratic tardy penalties for late job completion. Extensive research was carried out to identify a possible gap in the existing models. Due to this, it was possible to identify that the models addressed by the literature lacked the possibility of overlapping jobs. The proposal therefore originates from a pre-existing model that optimizes the penalties for early delivery by inserting idle times that cause the reduction of the earliness penalties. The proposed model starts with a heuristic method that provides an initial solution. In addition to this, the algorithm for inserting idle time generates a first optimization followed by a second optimization that overlaps the jobs so that a job can start before the initial job is completed with the objective of reducing the penalty for late completion. For the present study, the following assumptions were made idle time is allowed, the first job starts at time zero, all jobs are independent, and these can overlap up to a certain limit of compliance. The parameterization and simulations were carried out where the results obtained show that through the overlapping of jobs, the reduction of lateness penalties is achieved, which therefore leads to the validation of the proposal.

The COVID-19 pandemic caused the education sector to switch from face-to-face classes to non-face-to-face classes as a result of biosecurity measures. Then, guaranteeing meaningful distance learning became an essential necessity. This document analyzes the application of project-based learning (PBL) combined with collaborative learning strategies and its effects on the effectiveness of higher education in Control Theory Course of the Faculty of Electrical Engineering at the Technological University of Panama. The analysis showed that the methodology is a complementary tool that facilitates and enhances a learning environment that greatly develops critical and reflective thinking in students, qualities that every engineering professional should have. The results show that the projects developed by students can become self-learning units for other students, providing direct feedback on the concepts seen in the course.

In the present work, we seek to solve a partially flexible scheduling problem, energetically efficient, with sequence dependent setup time, cost penalties for both early and late completion, and preventive maintenance. These variables and objectives were selected because it is considered that these are the ones that have the greatest impact on the day-to-day of companies. For the solution, a genetic algorithm compatible with the proposed variables and capable of obtaining a solution efficiently is proposed. To check the operation of the proposal, the algorithm is tested with a simulation that combines data from other works with fictitious information. The algorithm found a solution for the three proposed objective functions from the information of five generations of data. The result was an optimal schedule, the total makespan and the cost of tardiness and earliness that could not be avoided.  

The objective of the research was to determine the dietary intake of Omega 3, 6, and 9 fatty acids in adults in Panama. This is a descriptive and cross-sectional study of 316 people of both sexes, between 18 and 50 years old. A semi-quantitative online food consumption frequency questionnaire was applied for two months. Sociodemographic data were also collected using a Google form over the Internet. Intake was estimated using the Costa Rican fatty acid composition table and models of portions of food sources of these fatty acids. The median and interquartile range for the daily consumption of Omega-3 was 0.89 (1.22) g/day; of Omega-6 of 12.56 (16.78) g/day; and of Omega-9 16.23 (18.54) g/day. Meats and derivatives, as well as oils and fats, are the main sources of Omega-3, 6, and 9 fatty acids in the diet, with Omega-3 being 1.15 (2.16) g/day, Omega-6 being 53.93 (101.13) g/day. g/day and Omega-9 of 39.32 (68.26) g/day for oils; and Omega-3 of 1.44 (1.32) g/day, Omega-6 of 14.78 (14.93) g/day and Omega-9 of 38.73 (37.12) g/day, for meats. The median Omega-6/Omega-3 intake ratio was 15.2:1 g/day; for Omega-9/Omega-3 it was 23.5:1 g/day, and for Omega-9/Omega-6 it was 1.27:1 g/day. In conclusion, low consumption of Omega-3 and high consumption of Omega-6 and Omega-9 is observed, especially in the interior of the country and at lower levels of education.

Due to the environmental problems caused by the production of conventional plastics, it has been decided to develop alternatives such as the production of polymers from renewable sources, which can be obtained from raw materials rich in starch. The synthesis of these materials requires the establishment of working conditions, in addition to the dimensioning of equipment to achieve maximum efficiency. In this sense, the present work aims to design a chemical reactor for the production of polylactic acid, establishing the main characteristics of the product and the most relevant data for the design. The polymerization was carried out by the ring opening method (ROP), with the synthesis of lactide in the presence of methanol and tin chloride (II) as catalyst. Among the results obtained, the volume of the reactor is presented as a function of the polymerization rate, which is 3.74 L, the density of the product was 1,171.21 kg/m3, the reaction rate was 0.0036 mol/L*h and a required power of 0.14 kW, which indicates that the implementation of a three-phase motor is not necessary. The sizing of equipment is an aspect that considers the design of plants, therefore the availability of raw materials, operating conditions and process yields must be considered, for an adequate calculation of reactors to be used in polymerization processes.

The methodologies for the design and management of projects are increasingly necessary and applied with greater frequency in the public sector in Latin America. There are continually updates and new approaches in the management of investment projects, so the study of methodologies is relevant at the investigative level. The design of reliable research instruments that serve to promote the use of these methodologies is important to ensure quality in the process. Therefore, the objective of this study is to design and validate an instrument that allows the systematic collection and management of project information to obtain the variables that allow defining the appropriate methodology for each organization. In this study, the public sector has taken as a reference the Undersecretary of Fisheries Resources (SRP) in Ecuador. The instrument takes as reference the International Organization for Standardization (ISO) 10006 Standard, the Project Management Fundamentals Guide, by its name in English Project Management Body of Knowledge (PMBOK), the Project Design Methodologies of the Polytechnic University of Catalonia (MDP-UPC) and the National Secretariat for Planning and Development (SENPLADES) of Ecuador. As a result, a survey was developed, whose instrument was internally and externally validated based on reliability, content, and construct parameters. Factorial analysis was performed to determine variables using the SPSS statistical system. Finally, the designed instrument has been validated, ensuring that it is reliable and meets the necessary parameters to obtain variables that define the methodology for project development in the public sector of Ecuador.

This article aims to investigate and study the Political-Ideological Regionalism in the American Continent focusing on the different processes and structures that characterize political regionalization, with the objective of determining the ideological patterns that feed the evolution of the political tendencies that mark the process of integration. The research is based on a descriptive and qualitative methodology using a documentary method. The American Political-Ideological Regionalism of the last three decades has opened a new path in the insertion of the region in the International System, however, it presents deep divisions that respond to clear political factions that follow ideological patterns linked to the shifting interests of governments through time. In the case of the Republic of Panama, although it has helped build the region's political and ideological regionalism, in recent decades it has strategically adhered to multilateralist practices to achieve sovereign purposes. It is concluded that the construction of PoliticalIdeological Regionalism is characterized by outlining dynamic and clearly defined trends, although its integration tends to be asymmetric and far from building solidly cohesive blocks. Finally, Cooperation and Multilateralism emerge as allies in the search for regional consensus and depoliticize integration, using politics as the basis to achieve objectives and ideologies as the link to reach agreements.

Vitaminic supplementation is important to optimize the boar reproductive potential. The study was aimed to evaluate the sperm quality of boar ejaculates supplemented with fat-soluble vitamins and the effect of the conservation in seminal samples through time. Four boars of a commercial terminal line (Duroc*Pietrain) with average age of 25.3±8.8 months and known fertility, were used. Semen samples were collected in the morning, once per week. Animals were randomly allotted to two groups and fed either of the two treatment for 16 weeks: (1) control treatment (TC without supplementation of fat-soluble vitamin), (2) treatment containing 100% fat-soluble vitamin supplementation (TS) based on fat-soluble vitamin supplementation (A, D3, E). Differences were found (P<0.05) in the total motility of the ejaculate for treatment that received vitaminic supplementation (TS) (85.11±0.79%), regarding the control treatment (TC) (74.39±0.79%). The supplemented animals with vitamins showed higher progressive motility (P<0.05), regarding to TC (79.84±0.80%; 69.63±0.80%, respectively). No differences were found (P>0.05) in total motility and progressive motility values at 24 and 48 hours, but after the 96 hours of conservation differences were found (P<0.05) for both variables. Results of TS regarding TC in the curvilinear velocity (VCL), straight-line velocity (VSL), and linearity of forward progression (LIN) variables were higher (P<0.05), during the 24 h of conservation. The ejaculates conservation could contribute to the efficiency of management in the pig farms and can be affected by multiple factors where the supplementation and adequate nutrition could contribute to the seminal quality of boar.

Compassion fatigue is a term to describe the emotional, physical and psychological consequences of helping others. It mainly appears in jobs related to humanitarian assistance. The main aim of this article is to investigate the specific effects of working with victims of gender violence in these professionals.Three different research lines have been established: the first one of how working in gender roles affects their private life (two study samples have been compared: the first one made up of 80 gender specialists and the other one of 80 women who carry out their jobs in other areas), the second one about vicarious trauma and the third one referred to the discomfort caused by precariousness in psychosocial intervention. The outcomes show the following conclusions: 1) Gender experts suffer more negative effects when they face situations in their private life related to gender problems compared with the general population. 2) The majority of the professional interviewed suffered secondary post-traumatic stress symptoms as a result of working in violence. Social workers show the highest rate of symptoms, followed by psychologists and educators, educational assistants and administratives.3) The 78,7% of the psychosocial professionals group think that there is a lack of economical reward for their activity.This article also analyzed the fact that the topic ´gender´ arises frequently in their daily life, making difficult to disconnect from work.

Development NGOs (NGDOs) have adopted communication guidelines to improve the image they offer about the citizens of southern countries, paying specific attention to women. However, various investigations have shown that these entities have not managed to transcend neither the victimized and dependent image that they have used to represent them, nor the gender roles traditionally associated with the female population. On its behalf, the fourth feminist wave has raised new debates and questions that invite NGDOs to rethink the way they treat female figures in their messages. For this reason, this study proposes a new analysis to record any possible changes in the portrait of southern women outlined by these organizations before and after the most recent feminist emergence. Oxfam Intermón, a distinctive organization in the sector, has been taken as a reference and its magazines, published in the periods 2015-2016 and 2018-2019, have been chosen for a more detailed review. Three variables are studied: the presence of individual female figures, the roles assigned to them and their use as information sources. The results show that the presence of female figures is recurrent in the texts analysed. However, the traditional gender roles have not been broken. The potential of southern women as sources is also wasted, since their statements are generally limited to confirming the existence of the adversities indicated by the NGDO and to highlighting the benefits of the interventions they have received.