Uniciencia https://www.revistas.una.ac.cr/index.php/uniciencia <p>The mission of <strong>Uniciencia</strong>&nbsp;journal is to share, without profit, research results and offer high quality inputs to the national and international scientific community in such a way that they allow the scientific and cultural development of our society. It is a&nbsp;semiannual&nbsp;journal that began in 1984. The journal is indexed in: Scopus, SciELO, Redalyc, LATINDEX Catalog, DOAJ, Emerging Source Citation Index (ESCI), among others.<br><strong>Publishing Entity</strong>: Faculty of Exact and Natural Sciences. Universidad Nacional, Costa Rica.<br><strong>Thematic areas</strong>: biology, physics, computer science, mathematics, chemistry, topography and geodesy (and their teaching).<br><strong>E-ISSN</strong>: 2215-3470<br><strong>Contact</strong>: Yuri Morales-López, Editor • <strong>Email</strong>: revistauniciencia@una.ac.cr</p> en-US <p><span id="result_box" lang="en"><span class="hps">Authors who</span> <span class="hps">publish with this</span> <span class="hps">journal</span> <span class="hps">agree to</span> <span class="hps">the following terms</span>:<br><br> <span class="hps">1. 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The opinions expressed in the paper are the exclusive&nbsp;responsibility of the authors and do not necessarily represent the opinion of the editors or the Universidad Nacional. </span></p> <p><span id="result_box" lang="en"><br></span><span style="color: black; font-family: 'Helvetica','sans-serif'; font-size: 10pt; mso-ansi-language: ES-CR; mso-fareast-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-bidi-language: AR-SA;">Uniciencia Journal and all its productions are under&nbsp;&nbsp;</span><span lang="ES" style="font-family: 'Times New Roman','serif'; font-size: 12pt; mso-ansi-language: ES; mso-fareast-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-bidi-language: AR-SA;"><a href="https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es"><span lang="ES-CR" style="font-family: 'Helvetica','sans-serif'; font-size: 10pt; mso-ansi-language: ES-CR;"><span style="color: #0000ff;">Creative Commons Atribución-NoComercial-SinDerivadas 4.0 Unported</span></span></a></span><span style="color: black; font-family: 'Helvetica','sans-serif'; font-size: 10pt; mso-ansi-language: ES-CR; mso-fareast-language: ES; mso-fareast-font-family: 'Times New Roman'; mso-bidi-language: AR-SA;">.</span></p> <p><strong>There is neither fee for access nor Article Processing Charge (APC)</strong></p> revistauniciencia@una.cr (Yuri Morales López) revista@una.ac.cr (Área UNAWEB) Mon, 31 Jan 2022 00:00:00 -0600 OJS http://blogs.law.harvard.edu/tech/rss 60 Excess Mortality Data Analysis of COVID-19 Infections and Fatalities in Ecuador https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16275 <p>The global COVID-19 pandemic has shocked the world. Since the virus gave rise to health problems and often ended in deaths, the count of the contagion and the deceased has been an open issue. Such statistics are vital for every nation and even every city or district and suburb as these numbers decide the level of intervention and the subsequent reduction of its given spread. Worldwide data show a mortality rate of around two percent prior to successful vaccination campaigns. However, Ecuador's statistical data indicate an abnormal amount of excess mortality, which is officially denied in each of the studied countries. These numbers have been projected on a monthly basis and exceed up to 300% of the official COVID-19 deaths. In particular, the average mortality rate in Ecuador, prior to and close to the pandemic, has been about 6083.4±234.6, while in the worst month during the sanitary crisis, deaths piled up to 21,000 people, and only 1180 were recognized as deceased by COVID-19. The reasons are widespread but based on an insufficient financed health sector, political incompetence, lack of leadership, and a long-lasting economic crisis. Therefore, premature endings of confinements or lockdowns have contributed to an accelerated contagion and seem to even counteract the vaccination phase, in middle 2021, shortly before excess mortality ceased completely.</p> Theofilos Toulkeridis, Esteban Ortiz-Prado, Jamileth Chunga-Moran, Marco Heredia-R, Alexis Debut (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16275 Mon, 31 Jan 2022 00:00:00 -0600 Covid-19 Vaccine Distribution: Combining SEIR and Machine Learning https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15216 <p>The purpose of this study is to build an epidemic model with vaccination control for Covid-19 in El Salvador. A combination of epidemiological SEIR (Susceptible, Exposed, Infectious or Recovered) models and the estimation of parameters using machine learning and contact networks is proposed. The project consisted of three phases: a) Analysis: the critical or key factors or variables of the phenomenon under study were identified, the model to be used, as well as its parameters and components, were defined, designed, and constructed b) Simulation: simulation made it possible to modify variables, implement alternatives, and modify the model itself without affecting the real system, which is highly useful for decision-making and preparing results and recommendations. The simulations were carried out using population data from El Salvador. c) Optimization: different scenarios were evaluated in which vaccination control measures and social distancing measures were applied, in order to identify the optimal strategy. As a result of this study, the best strategy for controlling the disease was identified: a combination of vaccinating the vulnerable population and maintaining social distancing measures provided the best results in terms of reducing the impact of infection and minimizing treatment costs. Finally, recommendations are made to government health authorities for distribution and application of the treatment.</p> Víctor Edgardo López-Sandoval (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15216 Mon, 31 Jan 2022 00:00:00 -0600 An Efficient Convolutional Neural Network to Detect and Count Blood Cells https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16303 <p>Blood cell analysis is an important part of the health and immunity assessment. There are three major components of the blood: red blood cells, white blood cells, and platelets. The count and density of these blood cells are used to find multiple disorders like blood infections (anemia, leukemia, among others). Traditional methods are time-consuming, and the test cost is high. Thus, it arises the need for automated methods that can detect different kinds of blood cells and count the number of cells. A convolutional neural network-based framework is proposed for detecting and counting the cells. The neural network is trained for the multiple iterations, and a model having lower validation loss is saved. The experiments are done to analyze the performance of the detection system and results with high accuracy in the counting of the cells. The mean average precision is achieved when compared to ground truth provided to respective labels. The value of the average precision is found to be ranging from 70% to 99.1%, with a mean average precision value of 85.35%. The proposed framework had much less time complexity: it took only 0.111 seconds to process an image frame with dimensions of 640×480 pixels. The system can also be implemented in low-cost, single-board computers for rapid prototyping. The efficiency of the proposed framework to identify and count different blood cells can be utilized to assist medical professionals in finding disorders and making decisions based on the obtained report.</p> Rakesh Chandra Joshi, Saumya Yadav, Malay Kishore Dutta, Carlos M. Travieso-González (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16303 Wed, 30 Mar 2022 00:00:00 -0600 Automated Quantification of Ki-67 on Gastric Epithelial Tissue based on Cell Nuclei Area Ratio https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16155 <p>The objective was to develop an automated algorithm for the estimation of a protein (Ki-67) index based on cell nuclei area ratio of gastric epithelial tissue cells; for this purpose, digital histopathology images were used. An expert manually annotated each region of interest of the images. A proportion of Ki-67 positive and negative cells within that region was used to obtain the color distribution of the corresponding pixels. The histogram of each color distribution was modeled as a Gaussian and, later, thresholded for segmentation and classification. Finally, the Ki-67 index was estimated as the ratio between the segmented positive area of the nuclei divided by the total area of the positive and negative nuclei. The automated method has a strong correlation of 0.725 and a root mean square error of 0.293 when compared to the manual method, which gives certainty that the automated method can be used to analyze the proliferation rate. Furthermore, compared to manual classification, the presented method automatically classifies every image in the same Ki-67 category: low, intermediate, and high. Despite the small sample size, the utility of the presented method was demonstrated. However, the low number of scored images did not allow for thoroughly sampling the ranges of pixel values and intensities observed by pathologists, which will be addressed in future work.</p> Austin Blanco-Solano, Francisco Siles Canales, Warner Alpízar-Alpízar (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16155 Wed, 30 Mar 2022 00:00:00 -0600 Sphingolipid pathway as a biosensor of cancer chemosensitivity: a proof of principle https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16127 <p>Cancer is a complex genetic disease with reduced treatment alternatives due to tumor heterogeneity and drug multiresistance emergence. The sphingolipid (SL) metabolic pathway integrates different responses of cellular stress signals and defines cell survival. Therefore, we suggest studying the perturbations on the sphingolipid pathway (SLP) caused by chemotherapeutic drugs using a systems biology approach to evaluate its functionality as a drug response sensor. We used a sphingomyelin-BODIPY (SM-BOD) sensor to study SL metabolism by flow cytometry and live cell imaging in different cancer models. To decode pathway complexity, we implemented Gussian mixture models, ordinary differential equations models, unsupervised classification algorithms and a fuzzy logic approach to assess its utility as a chemotherapy response sensor. Our results show that chemotherapeutic drugs perturb the SLP in different ways in a cell line-specific manner. In addition, we found that few SM-BOD fluorescence features predict chemosensitivity with high accuracy. Finally, we found that the relative species composition of SL appears to contribute to the resulting cytotoxicity of many treatments. This report offers a conceptual and mathematical framework for developing personalized mathematical models to predict and improve cancer therapy.</p> José Arturo Molina-Mora, Susana Mesen-Porras, Isaac Quiros-Fernandez, Mariana Kop-Montero, Andrea Rojas-Cespedes, Steve Quiros, Francisco Siles, Rodrigo Mora (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16127 Tue, 01 Nov 2022 00:00:00 -0600 A Systematic Review About the Contribution of The Genus Tessaria (Asteraceae) To Cancer Study and Treatment https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15997 <p>Belonging to the Asteraceae family, <em>Tessaria</em> (Ruiz &amp; Pavon, 1753) is a genus of shrubs or small trees distributed in various habitats located from Argentina to the southwestern United States of America. The taxa are composed of five confirmed species, which have been previously reported for their ethnopharmacological uses as hypocholesterolemiant, hypoglycemic, antitussive, anti-inflammatory, anticancer, and abortifacient agent; it also has been used in hepatic, renal, pulmonary, and rheumatic diseases. Up to the present, <em>T. absinthioides</em>, <em>T. ambigua</em>, <em>T. dodoneifolia</em>, <em>T. fastigiata</em> and <em>T. integrifolia</em> have been chemically analyzed. While decoctions, infusions, methanolic, and hydromethanolic extracts are the most studied botanical compounds, its most recognized phytochemical constituents are caffeoylquinic acid, eupatorin, naringenin, protocatechuic, and quercetin. Scientifically, several biomedical properties such as virucidal, antibacterial, leishmanicidal, insecticidal, gastroprotective, antiasthmatic, hypoglycemic, and antiatherogenic were attributed to the genus. Concerning oncologic research, the chemicals produced by <em>Tessaria</em> have antitumor activities interfering with carcinogenesis, cell proliferation, metastasis, and angiogenesis. In addition, the natural extracts obtained from <em>Tessaria </em>species have biological activities closely related to cancer, acting as antioxidants and anti-inflammatories. In particular, it has been reported that <em>T. absinthioides</em> resulted cytotoxic against several cancer cell lines and acts as an antitumoral compound in murine models. Due to the aforementioned antecedents, the <em>Tessaria</em> <em>species</em> are considered undervalued within the oncological field; the goal of the current systematic review is to summarize the information available on the genus, relevant for cancer research and treatment.</p> Arianna Sosa-Lochedino, María Belén Hapon, Carlos Gamarra-Luques (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15997 Wed, 01 Jun 2022 00:00:00 -0600 Characterization of Three cDNAs Obtained by Spliced Leader-PCR Screening of a Taenia solium cDNA Library https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15998 <p>Cysticerci or metacestodes of <em>Taenia solium</em> cause cysticercosis, being the neurocysticercosis (NCC) the main pathology. The characterization of genes is essential for the knowledge of parasite biology, the understanding of the parasite-host relationship, and the identification of possible targets for diagnosis, treatment, and protection. The objective of this work was the molecular and bioinformatic characterization of three news cDNAs (TsTF10, TsAAP8, and TsrGAP8), obtained by spliced leader-PCR screening of a <em>Taenia solium</em> cDNA library. The sequences of the three cDNA were compared with the sequences in the nucleic acid and protein databases (GenBank, EMBL) and analyzed by bioinformatic programs (CDD-Search of the National Center for Biotechnology Information, Interpro of the European Bioinformatics Institute, Motif scan and Expert Protein Analysis System of the Proteomics Server from Swiss Institute of Bioinformatics). Considering the high identities with similar molecules of related helminths (<em>Taenia asiatica</em>, <em>Echinococcus granulosus</em>, <em>Echinococcus multilocularis,</em> and <em>Hymenolepis diminuta</em>) and the functional domains found, the TsTF10, TsAAP8, and TsrGAP8 genes of <em>Taenia</em> could act as a nuclear transcription factor gamma, a putative vacuolar ATPase membrane sector associated protein and a Rho GTPase activating protein, respectively. Although few B epitopes could be predicted in the sequences, it could be relevant to evaluate them as possible candidates for diagnosis and protection in cysticercosis. The characterization and analysis of these sequences and the prediction of their possible usefulness as antigens, vaccines, or therapeutic targets contribute to the designing and planning of future studies.</p> Oswgladys Garrido, Elizabeth Ferrer (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15998 Wed, 01 Jun 2022 00:00:00 -0600 Waste management: a study on generating organic fertilizer from oil and grease trap systems https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15725 <p>The grease and oil trap systems (GOTS) of four university food service establishments (FSE) were assessed and treated to evaluate the potential use of the sludge collected to produce compost. The sludge collected from each FSE was kept in a drying bed for 30 days (SDB), during which time calcium oxide was frequently added for stabilization. The sludge deposited monthly was reduced to half after the drying process and was then deposited in a composter and mixed for a period of 22 days with constant agitation. The compost obtained was treated with degrading enzymes and was denominated enzymatic composting (EC), while the remaining compost was not treated with enzyme and was denominated non-enzymatic compost (NEC). The total composting cycle of the sludge lasted 83 days, during which time various physical and chemical analyzes were conducted in the three types of substrates (SDB, NEC, and EC).&nbsp; The total time of the research was 2.5 years.&nbsp; The percentages of phosphorus, potassium, magnesium, and calcium suggest the use of the three substrates as organic fertilizer. A recommendation resulting from this research is to evaluate the sludge quality by mixing it with other substrates such as fruit peels with high nitrogen content and the sludge from wastewater treatment systems.</p> Julián Rojas-Vargas, José Mora-Barrantes, Pablo Herrera-Vargas, Vinicio Arias-Zuñiga (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15725 Mon, 31 Jan 2022 00:00:00 -0600 Distribution, richness, and molecular identification of spider crabs (Brachyura: Majoidea: Mithracidae) from Costa Rica https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15345 <p>The objective of this study was to determine the distribution, richness, and molecular identification of spider crabs in the Costa Rican Pacific and Caribbean coasts. Distribution maps were created for species of the Mithracidae family on the Caribbean and Pacific coasts of Costa Rica, based on exploratory samplings and spatio-temporal records of collections (1960 to 2016) provided by the Universidad de Costa Rica’s Museum of Zoology. In addition, phylogenetic relationships were explored using a multigene concatenated phylogenetic tree based on mitochondrial and nuclear gene fragments. Historical records reveal the presence of 24 species of mithracid crabs and their geographic distribution in the Pacific and Caribbean of Costa Rica, including islands on the continental and oceanic shelf. Molecular analyses confirm sister relationships between the clades <em>Ala-Maguimithrax, Omalacantha-Microphrys, Omalacantha+Microphrys-Teleophrys</em>, and a well-supported clade of species belonging to the genus <em>Mithraculus</em>. However, our concatenated molecular data set suggests a monophyletic relationship between <em>Thoe</em>, <em>Petramithrax</em>, and <em>Hemus</em>, differing from what was previously reported. The results obtained in this study will help in the development of strategies for the environmental protection of these marine resources, by providing a baseline for monitoring environmental degradation and destruction of habitats used by spider crabs on the coasts of Costa Rica. Furthermore, the molecular information obtained in this study will help future studies focusing on understanding the population genetics, phylogeography, regional gene flow, and divergence among species between the Caribbean and Pacific coast.</p> Carolina Sancho-Blanco, Luis E. Salas-Arce, Jorge Alfaro-Montoya, Rita Vargas-Castillo, Juan Antonio Baeza, Rodolfo Umaña-Castro (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15345 Mon, 14 Feb 2022 00:00:00 -0600 Nitrates Evaluation in the National Térraba-Sierpe Wetland https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14827 <p>This research aimed to describe, spatially and temporally, the concentrations of nitrates in correlation with anthropogenic activities surrounding the Sierpe River that crosses the National Térraba-Sierpe Wetland (HNTS). Although territorially protected by Costa Rican legislation, this wetland is surrounded by intense agricultural activity. In 2018, monthly monitoring of pH, nitrates, and dissolved oxygen was carried out in fourteen points of the river. A baseline around 5 mg NO<sub>3</sub><sup>-</sup> / L was obtained in periods without agricultural activities and peaks up to 20 mg NO<sub>3</sub><sup>-</sup> / L after fertilization activities. Correspondingly, a decrease in dissolved oxygen and pH was observed on days of high agricultural activity. In the months following fertilization, accelerated growth of aquatic plants and a general deterioration in mangrove reproduction were observed by collaborators of the HNTS management and surveillance program. Nevertheless, when high nitrates concentration in agricultural areas are observed,&nbsp; their decline is also observed in the direction of the river's flow until it reaches its mouth.&nbsp; This facts shows the still active function of the wetland and its importance in the processing of nitrates. To regulate activities not only in the territorial limit but also in the limits of the water system surrounding the HNTS is recommended to protect this ecosystem function.</p> Laura Hernández-Alpízar, Jesús Mora-Molina (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14827 Mon, 31 Jan 2022 00:00:00 -0600 Environmental contribution of Los Tajos wastewater treatment plant in the removal of physicochemical and microbiological pollutants https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/17070 <p>The objective of the study was to analyze the environmental contribution, in terms of removal of physicochemical and microbiological pollutants, from the Los Tajos Wastewater Treatment Plant (WWTP) to the Torres River. Physicochemical and microbiological data was analyzed including WWTP inflows and outflows (OBD, OCD, TSS, STT, N-NH<sub>4</sub><sup>+</sup>, P-PO<sub>4</sub><sup>3-</sup>, Oils, MBAS, and fecal coliforms). The difference in the concentration of pollutants in the Torres River before and after the construction of the WWTP was analyzed using R 3.6.1, associated with seasonality. According to the Dutch Index Methodology, the Torres River was severely polluted before the construction of the WWTP, and the degree of contamination increases following the WWTP discharge, mainly during the rainy season. The WWTP shows significant removal of seven of the eight parameters analyzed, with the most representative removal percentages being: TSS (68.5%), OBD (49.8%), and Oils (54.7%). The quantitative contribution of the WWTP to the Torres River was demonstrated by removing thousands of Mg of pollutants from wastewater during the years of operation (2015-2020), mainly OCD (26,791.8 Mg), STT (24,162.6 Mg), OBD (12,290.0 Mg), and TSS (30,267.7 Mg). Finally, building the WWTP’s next stages, including secondary treatment, is needed to improve the removal of organic matter, surfactants, and nutrients.</p> Carmen Mora-Aparicio, Carolina Alfaro-Chinchilla, Junior Pastor Pérez-Molina, Ilena Vega-Guzmán (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/17070 Wed, 01 Jun 2022 00:00:00 -0600 Disaster risk management: competencies for a new hydro-environmental culture https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15250 <p>The study was aimed to develop and validate competencies, methodologies, and teaching resources for a new hydro-environmental culture in disaster risk management for Costa Rican students and teachers of the second cycle of the <em>Cahuita Excelencia</em> Elementary School in Limón. The research was developed under an interpretive and propositional qualitative approach with the participation of nine national and international experts (3 in Disaster Risk Management [Group 1], 3 in Climate Change [Group 2], and 3 in Education [Group 3]), using the Delphi method which consisted of 3 phases: preparation, consultation, and consensus. Results indicate that Groups 1 and 2 developed 43 competencies, of which ten were validated by each group. Group 1 distributed competencies into conceptual, internal, and external, while Group 2 only distributed cognitive competencies, both for children and teachers, taking into account indicators, didactic resources, and methodologies. During Phase 3, Group 3 adjusted and validated the competencies developed by Groups 1 and 2, which consist of 20 competencies and a series of resources and methodologies. It is concluded that competencies will contribute to guarantee better preparation for vulnerability and risk events caused by climate change. The reference educational material could be adjusted to other regions of Costa Rica and Latin America.</p> Jeannette Arauz Muñoz, Cristian Moreira Segura, Claudia Charpentier Esquivel, Gustavo Barrantes Castillo (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15250 Mon, 31 Jan 2022 00:00:00 -0600 Spectral reconstruction of kilovoltage photon beams using generalized simulated annealing https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16520 <p>To unfold the energy spectrum of two kilovoltage (kV) X-ray beams from transmission curves through a mathematical methodology based on Laplace transform and the generalized simulated annealing algorithm. Energy spectra of photon beams and transmission data were associated by means of a mathematical expression derived from the analytical solution of Laplace transform. Transmission data was calculated by relating the air kerma of the attenuated beams, passing through aluminium plates of different thickness, to that of the non-attenuated beam. Generalized simulated annealing function, developed in an early work, was employed to find the parameters of the expression and so determine the spectra. Validation of the methodology was done by the comparison of the half-value layers obtained from transmission curves and the spectra. The mean square percentage error between transmission data and fitting curve of each spectrum defined from the parameters found was lower than 1% indicating a good adjustment. The same error was observed when the first half-value layer (HVL) from the transmission curves and those of each reconstructed spectrum were compared. Calculation time of parameters was 5 sec for 80 kV and 14 sec for 120 kV. In no case, non-realistic solution of energy spectra was obtained. These results were better than an early work where least-squares were used. The reconstruction methodology based on generalized simulated annealing employed in this manuscript can efficiently derive the spectra of two X-ray beams with comparable accuracy to previous work. A limitation is that validation was not done by comparing data with the equipment’s spectra.</p> Jorge Homero Wilches-Visbal, Danny Giancarlo Apaza-Veliz, Patrícia Nicolucci (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16520 Mon, 31 Jan 2022 00:00:00 -0600 Tectona grandis L.f. clonal selection for the dry Pacific zone of Costa Rica https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14910 <p>Teak has the highest value of any commercially planted tree species in the tropics. The tree improvement international cooperative GENFORES, established in Costa Rica, has led breeding programs with this tree species in Latin America. This investigation was undertaken with the objective of selecting the clones which are best adapted to the dry Pacific zone of Costa Rica, as well as for other dry regions in the tropics. Research was carried out in Nicoya, in the province of Guanacaste (in the northern Pacific region of Costa Rica), where 31 genotypes were evaluated for 13 continuous years, in terms of diameter growth, commercial volume, and stem quality. Genetic parameters were obtained using Selegen-REML/BLUP software, as were selection rankings and estimated genetic gain. The highest values for individual heritability and mean clonal heritability for diameter (h<sup>2</sup>g = 0.12 and h<sup>2</sup>mc = 0.82), and for commercial volume (h<sup>2</sup>g = 0.075 and h<sup>2</sup>mc = 0.74) were obtained for trees that were 8.9 years old. Commercial plantations established with the best 10 clones, with an age of 12.9 years, may attain a commercial volume of 0.88 m<sup>3 </sup>per tree, corresponding to a genetic gain of 11% with respect to the best available seed source from a seed orchard, while diameter would reach 28 cm at the same age. These results allow a reduction of approximately two years of the age at which teak can be harvested in the dry Pacific zone of the country.</p> Yorleny Badilla-Valverde, Olman Murillo-Gamboa (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14910 Mon, 14 Feb 2022 00:00:00 -0600 An overview of the synthesis of graphene by liquid-phase exfoliation: mechanisms, factors, and techniques https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15786 <p>The objective of this article is to create a consensus about the graphene production by the liquid-phase exfoliation (LPE) method, as well as to understand the key causes and factors affecting the yield and quality of the graphene obtained. An exhaustive bibliographic search was conducted in Google Scholar given the extent of its collection. The results of the search are ordered by relevance, giving priority to key causes and physical phenomena related to LPE. The articles focused on understanding physical and chemical phenomena were classified in the mechanism section, in order to have a better understanding of the method at the molecular level. With this information, a classification of the most common LPE techniques (sonication, microfluidics, etc.) is proposed in order to reach a consensus on which techniques belong to the LPE method in function of their mechanism. The proposed classification aims at developing new techniques to significantly improve the performance of this method. From this systematic review, it is concluded that the liquid-phase exfoliation method is robust and very attractive to the industry and has easy scalability with high performance in relation to the techniques analyzed.</p> Carlos Daniel Galindo-Uribe, Patrizia Calaminici, Omar Solorza-Feria (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15786 Wed, 01 Jun 2022 00:00:00 -0600 Social networks in wildlife protected areas of Costa Rica https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14913 <p>This article compares social participation networks in three wildlife protected areas in the Central Pacific of Costa Rica. These areas represent different management categories, which means different approaches to the use of natural resources. A mixed approach methodology was used to have a wider understanding of the socio-environmental processes in these areas. Analyses used included graph theory, social network analysis, and heat maps with attribute variables and global and positional network indicators. The elements of analysis included 40 civil society groups related to local development and environment conservation organized between 2009-2010 and 40 between 2019-2020. The analysis units were the interactions among the groups. Results show that the more centralized the social networks and the less power of local and multisectoral groups, the greater the dissociation of the topics related to sustainability of wildlife protected areas and the more vulnerable to structural and external changes. It is concluded that, from the structural dimension, participation networks are influenced by the management categories, since they condition the access to their ecosystem services. From the functional dimension, the capability of participation networks to transform ecosystem services into development opportunities is irrespective of the management categories, although it is related to other social aspects.</p> Melissa Marín Cabrera (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14913 Mon, 31 Jan 2022 00:00:00 -0600 Surface water quality and socio-environmental pressures in the upper microbasin of the Poás river https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15327 <p>The objective of this research was to determine the quality of surface water in the upper part of the Poás river micro basin and the main socio-environmental pressures that may be related to current quality indices. An exploratory study with a quantitative approach was carried out in which the main socio-environmental pressures experienced by the water resource in the area were identified, while the quality of the surface water was determined based on physical, chemical, and microbiological indicators, as well as the application of two quality indices. Six socio-environmental pressures with a negative impact on the resource were found and related to specific actions carried out in homes and other socio-economic activities. Despite the fact that the evidence showed overall compliance between the analyzed parameters and quality criteria used nationally and internationally, the indices revealed incipient contamination levels, as well as good and medium quality. Statistically, it was found that water quality of the micro-basin does not vary spatially; however, it does vary temporarily due to the incidence of rainfall patterns in the area. This finding, along with the determination of significant correlations between the monitored parameters, contributed to the recognition that the sites monitored in the rainy season have a stronger relationship with parameters associated with organic pollution linked to runoff and wastewater discharge processes. Therefore, it is necessary to coordinate efforts that guarantee sustainability of the micro basin that improve the local sanitary infrastructure, strengthen water management processes, and are focused on the establishment of a monitoring network within a reference framework oriented towards basins.</p> Kelvin Arce-Villalobos, Rolando Sánchez-Gutiérrez, Jacqueline Centeno-Morales, Rolando Marín-León, Jorengeth Abad Rodríguez-Rodríguez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15327 Thu, 10 Mar 2022 00:00:00 -0600 Obtaining leveled heights by GPS leveling. Case study: Morona – Ecuador https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16077 <p>The aim of the study was to demonstrate the applicability of GPS leveling to obtain accurate leveled heights for engineering purposes, in the canton of Morona, Ecuador. Two working scales were evaluated: cantonal (macro) and urban (micro), where the known vertices from which the height value was determined were points that belong to the local geodesic network of the canton. Based on the analysis of the geoid undulation gradient, 5 homogeneous zones of the gradient variation were defined; GPS leveling was applied in the two zones (zone 4 and 5) that had geodesic vertices and that also cover a larger area of the canton. The geoid undulation gradient values in the study area were highly variable, with errors of up to 24 mm/km. At the cantonal scale, errors were reached between 12.19 cm - 1.27 cm at 30 Km - 5.1 Km in zone 4, and 38.48 cm - 8.33 cm at 13 Km - 2.7 Km in zone 5, while on an urban scale, errors of 2.48 cm - 0.14 cm were found at 1.07 Km - 0.19 Km, respectively. Using GPS leveling, useful results are obtained for engineering jobs and geoscience jobs in general, that require the determination of leveled heights quickly and accurately. For the correct application of this technique, two determinants must be considered: the baseline distance and the geoid undulation gradient.</p> Iván Fernando Palacios-Orejuela, Karol Dennise Arellano-Pérez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16077 Thu, 10 Mar 2022 00:00:00 -0600 Accurate Symmetry Calculation with Normalized Dynamic Time Warping Gait Symmetry Ratio https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16379 <p>In this paper we propose a new method for symmetry calculation in wearable devices. The problem in this domain is that only discrete features such as stride length, stride duration, or duration of gait phases are used for the symmetry calculation. However, this can lead to failures, since the use of features can result in partial loss of information from the time series. From this we present a possibility to calculate the symmetry by using Dynamic Time Warping (DTW). DTW uses the complete time series for the analysis and is therefore independent of certain features.</p> Tobias Steinmetzer, Ingrid Bönninger, Carlos M. Travieso-González (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16379 Tue, 01 Nov 2022 00:00:00 -0600 Pros and Cons of Computer-Assisted Rehabilitation https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16095 <p>This article summarized the knowledge obtained from exercises with patients using computer-assisted rehabilitation. Working with a wide base of healthy individuals and patients with various problems yielded the results to summarize. This work utilized several rehabilitation devices using computer games and uncovered positive and negative aspects of contemporary rehabilitation procedures. we conclude in this research computer-assisted rehabilitation is the future of modern rehabilitation, so it is necessary to know all factors affecting patients’ health.</p> Norbert Ferenčík, Radovan Hudák, Miroslav Kohan, Viktória Rajťúková (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16095 Wed, 30 Mar 2022 00:00:00 -0600 The Transformation of RGB Images to Munsell Soil-Color Charts https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16087 <p><strong>[Objective]</strong> The transformation from RGB to Munsell color space is a relevant issue for different tasks, such as the identification of soil taxonomy, organic materials, rock materials, skin types, among others. This research aims to develop alternatives based on feedforward networks and the convolutional neural networks to predict the hue, value, and chroma in the Munsell soil-color charts (MSCCs) from RGB images. <strong>[Methodology]</strong> We used images of Munsell soil-color charts from 2000 and 2009 versions taken from Millota <em>et al</em>. (2018) to train and test the models. A division of 2856 images in 10% for testing, 20% for validation, and 70% for training was used to build the models. <strong>[Results]</strong> The best approach was the convolutional neural networks for classification with 93% of total accuracy of hue, value, and chroma combination; it comprises three CNN, one for the hue prediction, another for value prediction, and the last one for chroma prediction. However, the three best models show closeness between the prediction and real values according to the CIEDE2000 distance. The cases classified incorrectly with this approach had a CIEDE2000 average of 0.27 and a standard deviation of 1.06. <strong>[Conclusions]</strong> The models demonstrated better color recognition in uncontrolled environments than the Transformation of Centore, which is the classical method to transform from RGB to HVC. The results were promising, but the model should be tested with real images at different applications, such as soil real images, to classify the soil color.</p> Martín Solís, Erick Muñoz-Alvarado, María Carmen Pegalajar (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16087 Wed, 01 Jun 2022 00:00:00 -0600 Bone level around dental implants adjacent to teeth and implants https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16519 <p><strong>[Objective]</strong> This investigation seeks to determine the difference in bone level around implants adjacent to teeth and implants. <strong>[Methodology] </strong>This cross-sectional study included 17 patients with a total of 51 stable implants with a functional loading of at least 6 months. These implants were located next to natural teeth, other implants, or both. All implants and adjacent teeth were clinically examined, and periodontal and peri-implant parameters were recorded. A radiographic analysis was carried out to measure the bone level around implants in relation to the implant platform. Data were analyzed to detect differences between bone levels on the side of an implant next to a tooth compared to those on the side of an implant next to another implant. Statistical differences were considered significant when p≤0.05. <strong>[Results]</strong> The distance from the crestal bone on the coronal side of the implant platform to adjacent teeth or implants was approximately 1 mm. The bone level in zones adjacent to other implants was more apically located (2.9 ± 1.4 mm) than was the case for bone levels on sides adjacent to natural teeth (1.3 ± 0.07 mm) and the difference in these distances was statistically significant (p&lt;0.05). Bivariate analysis showed that the bone level around implants was more likely to be coronal in relation to the implant platform on the side adjacent to a tooth than on the side adjacent to another implant (p=0.04). <strong>[Conclusions]</strong> The results indicate that the bone level of implants adjacent to natural teeth is maintained more coronal as compared to implants adjacent to other implants. This suggests a greater stability of implants when they are located near remaining natural teeth.</p> John Jairo Gómez-Guzmán, Yohana Marcela Arias-Holguín, María Isabel Pérez, Felipe Augusto Restrepo-Restrepo, Carolina Rodríguez-Medina, Javier Enrique Botero (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16519 Mon, 31 Jan 2022 00:00:00 -0600 Tooth whitening in conventional orthodontic patients: a systematic review https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16696 <p>This systematic review aimed to identify and critically evaluate the available evidence of the appropriate moment to perform tooth whitening in conventional orthodontic patients. A systematic review in MEDLINE and SciELO databases from inception to February 2021 was carried out by two independent reviewers. Randomized clinical trials, non-randomized clinical trials, case-control, cohort, cross-sectional, case-series and reviews that focused on the application of tooth whitening during or after orthodontic treatment were considered for inclusion. The primary outcome was defined as tooth whitening during/after orthodontic treatment. The secondary outcome included the time in days after bracket debonding in which tooth whitening was performed. Risk of bias analysis was performed for each study and the findings were synthesized in a narrative summary. A total of 4 randomized clinical trials, 1 non-randomized clinical trial and 3 reviews were included in the qualitative synthesis. One study performed tooth whitening during, and three studies after orthodontic treatment. One study compared tooth whitening during and after orthodontic treatment. The time after which tooth whitening was applied following bracket debonding ranged from 7 to 90 days with a mean value of 40.2 days. All studies reported satisfactory improvements in tooth color shade during or after orthodontic treatment independent of the protocol. Low quality evidence suggests that the appropriate moment to perform tooth whitening in conventional orthodontic patients is after brackets removal with a waiting period of at least 30 days. There is not adequate evidence to support tooth whitening during conventional orthodontic treatment.</p> Stefanía Hernández-Viana, Miguel Fernando Niño, Felipe Augusto Restrepo, Javier Enrique Botero (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16696 Mon, 14 Feb 2022 00:00:00 -0600 Measuring Traffic Dynamics at the Edge https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16189 <p>This work aims to measure the impact of approximate computing on a case study of traffic dynamics metering on a System-on-Chip edge computing device. Firstly, the study proposes a baseline implementation of the metering system in C++. To analyze the application in detail, study profiled the baseline using a built-in instrumented profiler, presenting the overall performance of each of its parts. During the hotspot analysis, some parts had optimization opportunities exploitable by multi-threading and approximate computing techniques, particularly frame skipping, which is inspired by the loop perforation approximate technique. The first optimization employed was multi-threading, which led to a 1.32x speedup on the application without introducing errors in the metrics. Then, the meter was optimized by using frame skipping. This work demonstrated that adaptatively modifying the number of frames skipped improved the error in the final metrics compared to keeping it fixed. In terms of performance, the frame skipping brought the overall speed up to 1.76x. Approximate computing, in particular, frame skipping, managed to contribute up to 25% of the overall speedup, managing to accelerate the meter from 8.7 frames per second to 15 fps in the most critical case in exchange for some numerical error on the final metrics.</p> Luis Gerardo León-Vega, Jorge Castro-Godínez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16189 Tue, 01 Nov 2022 00:00:00 -0600 Bioinsecticides used against Spodoptera spp. in the cultivation of watermelon (Citrullus lanatus T.) in Los Ríos, Ecuador https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16093 <p><strong>[Objective]</strong> The objective of this work was to analyze the use of organic insecticides from extracts of different plants to control the impact produced by the caterpillar pest <em>Spodoptera</em> spp. on the watermelon (<em>Citrullus lanatus</em>) crop in the province of Los Ríos, Ecuador. <strong>[Methodology]</strong>&nbsp; A randomized&nbsp;complete&nbsp;block&nbsp;design (RCBD) was used, consisting of five treatments with four replicates, with different extracts and a control. Treatment T1 consisted of <em>Capsicum sativum</em> chili bell pepper extract plus common soap; treatment T2 consisted of <em>Allium sativum</em> garlic extract with liquid paraffin vegetable oil plus common soap; treatment T3 consisted of <em>Urtica dioica</em> nettle extract; treatment T4 consisted of <em>Ruta graveolens</em> rue extract, and treatment T5 was defined as a control. Differences between results of treatments were compared using Tukey’s test. Results were considered to be statistically significant when p ≤ 0.05. <strong>[Results]</strong> The T3 treatment was most effective, producing the lowest percentage of pest incidence (an average of 25%), and the lowest percentage of fruit damage (an average of 10%). It was followed by T1 (32.50% pest incidence) and T2 (35.00% pest incidence). The T5 control produced negative results, with 50% pest incidence and 37.50% fruit damage. <strong>[Conclusions]</strong> The study demonstrated that nettle extract, used as a botanical extract for the potential control of <em>Spodoptera</em> spp. in the watermelon crop produced the lowest incidence of pests (25%), demonstrating the usefulness of botanical extracts in sustainable horticultural production.</p> Víctor Ileer, Jorge Peralta, Christian Palacios, Alexis Burgos (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16093 Tue, 01 Nov 2022 00:00:00 -0600 Preliminary study on health effects and their relation to volcanic gas emissions exposure. A case study of two active volcanoes in Costa Rica https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/17654 <p><strong>[Objective]</strong> The objective of this research was to carry out a preliminary diagnosis of the relationship between volcanic gaseous emissions and health effects present among workers of the National System of Conservation Areas (SINAC) of the Poás and Turrialba volcanoes of Costa Rica. <strong>[Methodology]</strong> Ambient air quality was measured by the presence of gaseous emissions (SO<sub>2</sub>(<sub>g</sub>), H<sub>2</sub>S(<sub>g</sub>), HCl(<sub>g</sub>), HNO<sub>3</sub>(<sub>ac</sub>) and HF(<sub>g</sub>)), with sampling carried out in 7 strategic points during 7 months. Analyses were performed using different analytical techniques (ion chromatography, spectrophotometry, portable meters). At the same time, interviews were conducted with a sample consisting of 16 park rangers from the study sites, and their medical records were analyzed to detect a preliminary relationship between exposure to gaseous emissions and reported pathologies. <strong>[Results]</strong> The principal results (pollutants above the detection limit) reported for the two national parks indicated that the highest value in this study was that of SO<sub>2</sub> (average of 3 h) in the Poás Volcano (1.90 ± 0.11) mg/m<sup>3</sup>. The highest concentration of SO<sub>2</sub> in Turrialba was (0.40 ± 0.04) mg/m<sup>3</sup> during the same period. During the evaluation of park rangers’ health, it was found that the most frequently reported pathologies that impact health in the study population were irritation of the mucous membranes-eyes (n = 9), headaches (n = 8), and fatigue (n = 8). <strong>[Conclusion]</strong> The results obtained for the gaseous emissions and their possible relationship with pathologies and medical records indicated by park rangers provide a baseline for future research on the subject. A greater number of measurements over longer periods of time is recommended. At the same time, it is necessary to use surveys and carry out medical controls that include tests on specimens such as blood, urine, hair, and saliva, as well as the use of biological and chemical indicators that allow a pathology to be more directly related to a specific chemical contaminant.</p> Erick Ortiz Apuy, José Carlos Mora Barrantes, Jose Pablo Sibaja Brenes (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/17654 Tue, 01 Nov 2022 00:00:00 -0600 Exploring the use of remote sensing tools and geospatial technologies applied to the multidimensional food security problem https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16260 <p><strong>[Objective]</strong> The aim of this study was to analyze which role remote sensing technologies can play to study multidimensional factors influencing the Food and Nutrition Security (FNS), in Córdoba Argentina. <strong>[Methodology]</strong> The study area includes the city of Córdoba, Argentina. Epidemiological data on the prevalence of underweight, overweight, and obesity (malnutrition) in 2013 were obtained from 23 primary health care centers in the city. The environmental conditions of the surroundings of the health centers were explored within a radius of 1000m. SPOT 5 images were classified using spectral and spatial features and we show how a non-supervised classification can give information to describe the social dimension and economic access to food. In addition, a multivariate stepwise linear regression was performed to examine the relation between the prevalence of malnutrition and the environmental and spatial variables, derived from the SPOT image, proposed.&nbsp; <strong>[Results] </strong>The results of the unsupervised image classification show the difference in the spectral-spatial pattern of neighborhoods showing how a simple satellite image classification can become a useful discrimination tool. Multiple regression analyses with adjusted R2 of 0.70 and 0.6435 respectively are obtained for undernutrition, and overweight, and obesity. On the basis of the obtained models, continuous maps of prevalence are built. <strong>[Conclusions]</strong> The method proposed in this work can discriminate socially different areas related to FNS. It is innovative and necessary to take advantage of remote sensing tools and geospatial technologies, in our region, applied to FNS.</p> Eliana Marina Di Fino, Carlos Matias Scavuzzo, Micaela Natalia Campero, Carlos Marcelo Scavuzzo, María Daniela Defagó (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16260 Tue, 01 Nov 2022 00:00:00 -0600 Nanotechnology diffusion strategy: interdisciplinary teaching to primary school teachers https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15053 <p>The objective of the research was to disseminate nanotechnology concepts, applications, and benefits among educators from different Costa Rican provinces to increase their acceptance and dissemination of the subject to elementary students. Teachers from different areas of the country were called to participate.&nbsp; Five training workshops were held in Turrialba, Cahuita, Alajuela, Buenos Aires, and Nicoya covering fundamental nanotechnology concepts and applications, as well as the contributions offered from an educational point of view. The workshops were held in person two full days including talks, practical activities, and discussions. In addition, educational materials were prepared, such as a poster and an information brochure, and two educational videos on nanotechnology. A total of 98 teachers, 87% men and 13% women, from different provinces were trained. Workshop evaluations were positive in terms of the knowledge acquired with an average of 57.30%, compared to 5.10% before starting the training. This project contributed to strengthen teachers’ knowledge about nanotechnology and its applications. In addition, national and international nanotechnology research projects were made known. The above will help teachers disseminate new knowledge to the student population, thus becoming knowledge multipliers.</p> Melissa Camacho-Elizondo, Diego Batista-Menezes, Rodrigo Mora-Bolaños, José Roberto Vega-Baudrit, Gabriela Montes de Oca-Vásquez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15053 Mon, 31 Jan 2022 00:00:00 -0600 Criteria guiding mathematics professors practice in engineering basic science courses https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15727 <p>The study aims to infer the criteria that guide the practice of professors to explain mathematics, specifically derivatives, in a basic science course in the engineering program. This qualitative research of a multiple case study seeks to understand the teaching of differential calculus through the analysis of the practices of a group of seven professors, and the reflection on these practices when they implement their classes in engineering faculties of public and private universities in Lima, Peru. Each professor’s class was recorded. The criteria they follow to design and implement the classes were inferred, taking the didactic suitability criteria as a reference, which were also used to design the semi-structured interview questionnaire. Triangulation was done between what professors say and what they have been observed to do. It was noted that mathematics professors in engineering programs are completely conditioned by the subject syllabus when developing their derivative classes, as well as by the means and teaching resources and the availability of time for their differential calculus classes. Therefore, it is concluded that the priority criterion of the group of participating professors is meeting the curriculum in the time scheduled. On the other hand, they give more importance to adequately managing group interaction than teaching quality mathematics to be learned in a significant manner by students.</p> Walmer Garcés-Córdova, Vicenç Font-Moll (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15727 Mon, 31 Jan 2022 00:00:00 -0600 Specialized knowledge of polygons of math teachers in training https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14927 <p>The paper is aimed to understand the specialized knowledge shown by a secondary education teacher in training when teaching polygons as part of her pre-professional practice on her senior year. This exploration was based on the Mathematics Teacher’s Specialized Knowledge (MTSK) model developed by a research group in the University of Huelva, Spain. The research methodology was qualitative. Based on an interpretive approach, a case study was used to identify, describe, and understand the student teacher’s geometric knowledge of polygons. Information was collected through non-participant observation, using recordings of three sessions with fifth graders of secondary education. In order to validate the analysis, we used external expert triangulation in the MTSK model. The results show the potential offered by the MTSK model as a tool to deepen the characterization and understanding of teachers’ knowledge, favoring the initial training of secondary education teachers by allowing them to reflect on the need to have a mathematical and didactic knowledge of the content to be taught. Results show how the knowledge of polygons is closely related to the knowledge of teaching mathematics linked to this subject, as well as to the knowledge of the characteristics of mathematics learning.</p> Elizabeth Advíncula-Clemente, Marisel Beteta-Salas, José León-Ríos, Isabel Torres-Céspedes, Miguel Montes (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14927 Mon, 31 Jan 2022 00:00:00 -0600 Knowledge of mathematics teachers in initial training regarding mathematical proofs: Logic-mathematical aspects in the evaluation of arguments https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15060 <p>The objective of this study is to characterize the knowledge of mathematics teachers in initial training (MTITs) at the Universidad Nacional (Costa Rica) on the logic-syntactic and mathematical aspects involved in proving, when evaluating mathematical arguments. The research is positioned in the interpretive paradigm and has a qualitative approach. It consists of two empirical phases: in the first, a questionnaire regarding logic-syntactic aspects was applied to 25 subjects, during the months of September and October 2018 and; in the second phase, a second questionnaire covering mathematical aspects was applied to 19 subjects, during the months of May and June 2019. For the analysis of the information, knowledge indicators were proposed.&nbsp; Knowledge indicators are understood as phrases to determine evidence of knowledge in the responses of the subjects. It was appreciated that the vast majority of future mathematics teachers show knowledge to discriminate when a mathematical argument corresponds or not to a proof by virtue of the logic and syntactic aspects, and of mathematical elements associated with propositions with the structure of universal implication. In general, subjects displayed greater evidence of knowledge on the logic-syntactic aspects than on the mathematical aspects. Specifically, they evidenced that consideration of a particular case or the proof of the reciprocal proposition does not prove the result; likewise, subjects evidenced knowledge about the direct and indirect proof of the universal implication. In the case of the mathematical aspects considered as hypotheses, axioms, definitions and theorems, it was appreciated that subjects could have different levels of difficulties to understand a proof.</p> Christian Alfaro-Carvajal, Pablo Flores-Martínez, Gabriela Valverde-Soto (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15060 Mon, 31 Jan 2022 00:00:00 -0600 Persistent mathematical errors when entering initial teacher math training: the linearity case https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14903 <p>The objective of this research was to identify persistent errors of mathematical concepts and procedures, in particular, the incorrect application of the linearity concept, as well as implement learning situations to address errors of linearity by designing learning tasks in the context of modeling and the use of mathematical software. The study was applied to 42 students in the mathematics education program, during the 2019-2020 period. Research was conducted under a qualitative and longitudinal approach. Data collection began with a test upon&nbsp;entering the program and a second test after completing a semester of classes. Later on, collaborative workshops were implemented to address linearity errors, and a post-test was applied at the end. Upon entering the initial teacher math training, students showed a high percentage of errors, mistakenly applying linearity to roots, powers, logarithms, and trigonometry. After a semester of classes, these errors persisted. After the workshops, none of the participants made linearization errors in roots, powers and trigonometry, and only some continued applying linearity to logarithms. It was concluded that at the beginning of the program, students were still making errors in concepts and procedures that should have been overcome in school, and many of these errors are highly persistent. Using software in learning situations related to modeling would help students remedy those errors.</p> Maitere Aguerrea, María Eugenia Solís, Jaime Huincahue (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14903 Mon, 31 Jan 2022 00:00:00 -0600 Teacher Reflection on a Teaching-Learning Situation Regarding the Concept of Relation in Secondary Education https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15039 <p>This study is part of the research in <em>didactics of mathematics</em> on teacher training. In particular, the study focuses on the knowledge of mathematics teachers, taking as a reference the theoretical approaches of the Mathematics Teacher’s Specialized Knowledge (MTSK) model and teacher reflection as a professional competence. The study corresponds to a descriptive-qualitative research, based on an instrumental study of cases, whose purpose is to describe and analyze the manifestations of mathematics teachers of Secondary Education when they observe a teaching-learning situation that shows a teacher of mathematics teaching the concept of relation. For this, narratives written by seven Secondary Education mathematics teachers in service were used, which indicate some aspects identified by them as relevant from the observed situation. The analysis of the gathered information was carried out by defining categories, subcategories, and analysis units based on the components of the MTSK model. The results indicate that participating teachers accentuate, in their manifestations, attributes mainly associated with didactic knowledge of mathematical content. The reflection of this group of teachers is characterized by three specific aspects of the MTSK model: teaching, learning, and knowledge of the topics. It is interpreted that teacher reflection has been influenced by the professional experience of the teachers participating in the study.</p> Miguel Picado-Alfaro, José Romilio Loría-Fernández, Jonathan Espinoza-González (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15039 Mon, 31 Jan 2022 00:00:00 -0600 Implementation of the Mathematics curriculum in elementary school from the teacher’s perspective https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15056 <p>The objective of this paper is to analyze, from the perspectives of elementary school teachers, the processes they carry out in their classrooms in terms of methodologies and evaluations used in the development of programs for the study of mathematics. A mixed approach was used in the study, which was based on a sequential design. Non-probabilistic sampling was used for convenience. In the first phase of the research, 117 elementary school teachers from schools in Costa Rica were surveyed. In the second phase, interviews were conducted with three teachers. A questionnaire was used to collect data, and semi-structured interviews were also carried out. The results obtained show that implementation of the Mathematics curriculum led to methodological changes and adjustments in the process of evaluation among the teaching staff, but also created problems. In general, the blackboard was the most used resource, but the use of additional tools has diversified. There is little use of technology and discussion of the history of mathematics as teaching resources. Knowledge of the curriculum is not adequate; priority is given to content, rather than to the development of skills. The teaching staff has difficulty in planning and developing problem-solving activities. Teachers should participate in continuous training processes in areas including mathematical knowledge, methodological and evaluation strategies, use of technology, and problem solving.</p> Ronny Gamboa-Araya, Randall Hidalgo-Mora, Mario Castillo-Sánchez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15056 Mon, 31 Jan 2022 00:00:00 -0600 Gender, self-efficacy and performance in a mathematics test: The moderating role of the educational center https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16344 <p>&nbsp;[<strong>Objective</strong>] The purpose of the present study was to analyze the relationship between students’ mathematical self-efficacy and performance in the national high school graduation mathematics test, taking into account other relevant psychosocial predictors and the moderating effects of sex and educational center. [<strong>Methodology</strong>] The design of the study was observational and cross-sectional, with the participation of 487 eleventh-grade students from public secondary schools in the Greater Metropolitan Area of Costa Rica. Several instruments were applied for measuring hostile and benevolent sexism, perceptions of gender equality in mathematical abilities, mathematical self-efficacy and reasoning abilities. [<strong>Results</strong>] The results of the multilevel Bayesian random effects analysis confirmed that scores were higher for men than for women in measurements of self-efficacy, where the sex of the student body was a moderator in the relationship of mathematical self-efficacy and test scores. In addition, it was found that, depending on the sex of subjects, the association between self-efficacy and performance was also moderated by the educational center. [<strong>Conclusions</strong>] Among the conclusions, it is especially noteworthy that if the moderating effect of the educational center between self-efficacy and performance differs by sex, this implies that actions aimed at promoting self-efficacy will not have the same result in men and women, showing the need to develop differentiated interventions.</p> José Andrey Zamora-Araya, Eiliana Montero-Rojas, Vanessa Smith-Castro, Tania Elena Moreira-Mora, Pablo Zamora-Calvo, Karla Quintero-Arias, Stefani Matarrita-Muñoz (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16344 Tue, 01 Nov 2022 00:00:00 -0600 Guidelines for the analysis of mathematics textbooks lessons on the subject of proportionality https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15399 <p>The objective of this study is the construction of a guideline of indicators of didactic suitability related to the topic of proportionality, which can be used as a basis for the analysis and evaluation of textbook lessons, and as a resource for teachers’ reflection on effectively implemented instructional processes about proportionality. Since the study of proportional reasoning has become a relevant field of research in mathematics education, it is possible to identify specific suitability criteria for guiding the teaching and learning processes, applying the methodology of content analysis to a bibliographic review of key research in this area. Various aspects, components, and indicators of the notion of didactic suitability guide the selection and categorization of didactic-mathematical knowledge about proportionality in elementary and secondary education derived from research about such content. Finally, a <em>Mathematics Textbook Lesson Analysis Guide</em> adapted to the topic of proportionality was created. Since the textbook contains curricular material that largely determines what happens in the classroom and acts as a mediator in student learning, and ratios, proportions, and proportionality are studied in the curricula of elementary and secondary education, the Guide obtained can be a valuable resource for teachers. It is necessary to design and implement training actions with teachers that they are familiar with and can use competently, bearing in mind that there is always room for further improvement.</p> María José Castillo Céspedes, María Burgos Navarro, Juan Díaz Godino (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15399 Mon, 31 Jan 2022 00:00:00 -0600 Mathematical Modeling in Statistical Activities: Key Episodes for Model Generation https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16521 <p>This work is intended to assist 15-year-old secondary school students to learn about statistics using mathematical modeling. Specifically, open statistical problems are presented in which real social phenomena are studied by students using large data sets that comply with the design principles of <em>model-eliciting activities</em>. The tasks assigned are aimed at presenting the concept of variability and its application to understanding the situations studied using a mathematical model. The study focuses on identifying key episodes in the activities in which progress is made in the construction of mathematical models, and the elements that promote them. To do so, a qualitative analysis is carried out based on records of the students’ group work in the classroom using Modeling Activity Diagrams. The results obtained show that decisions about the design of a problem, such as using large amounts of data, or the ambiguity of social concepts such as “fair taxation,” are essential for promoting the development of mathematical models. The conclusions of this investigation have implications for the design of statistical tasks, and also for identifying the role of mathematical modeling in the learning of statistical concepts.</p> Àngels Aymerich, Lluís Albarracín (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16521 Mon, 31 Jan 2022 00:00:00 -0600 Mathematical Creative Thinking Ability and Self-Efficacy: A Mixed-Methods Study involving Indonesian Students https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15263 <p>With regard to creativity in mathematics, scholars tend to focus on the logical realm, which includes fluency, flexibility, and originality while overlooking the value of the affective domain, which includes self-efficacy, beliefs, and attitudes. The objectives of this study were 1) to investigate the extent to which self-efficacy affects students’ mathematical creative thinking ability; and 2) to determine the characteristics of students with high mathematical creative thinking ability and high self-efficacy. A mixed-method approach, that combined semi-structured interviews, and correlation analysis was employed to investigate the effect of self-efficacy on students’ mathematical creative thinking ability. The participants of the study were selected from junior high schools (JHS) in the city of Makassar. Ninety-six students (42 boys and 54 girls, aged 14 years old) completed a questionnaire assessing their mathematics self-efficacy. In general, the results proved that self-efficacy had an effect on JHS students’ mathematical creative thinking ability. This study also revealed that students with high self-efficacy are more likely to possess high mathematical creative thinking ability and vice versa. The characteristics of students with high mathematical creative thinking ability and high self-efficacy include excessive anxiety, reliance on key experiences, such as the ability to generate ideas (cognitive novelty), the ability to propose various solutions (cognitive variety), and the ability to change perceptions (cognitive framing).</p> Sri Rahayuningsih, Muhammad Nurhusain, Nenny Indrawati (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15263 Mon, 14 Feb 2022 00:00:00 -0600 Literacy and probabilistic thinking in pre-service and in service mathematics teachers https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15452 <p>The objective of this study is to characterize the literacy and probabilistic thinking skills that trainee and currently active mathematics teachers use when faced with real-world problems, in which uncertainty plays a role. A qualitative methodology was used, applying a case study design and the content analysis method. As a technique to obtain information, an open-question instrument was prepared based on two problem situations, which the participants were asked to complete. The 55 participants were selected through intentional or disposition sampling, 26 of whom were actively teaching, and 29 of whom were trainee teachers. Among the main results, it is worth noting that all teachers that participated in the study, both active and trainees, have not developed probabilistic skills that allow them to consider problems from the intuitive, classical and frequency perspectives, essentially resorting to the classical meaning of probability. In addition, there is little evidence of the development of conceptual and argumentative skills that allow comparing empirical and theoretical results. In conclusion, it was observed that both active and trainee teachers have not developed literacy skills and probabilistic thinking which would allow a way of teaching probability that goes beyond the purely algorithmic, promoting learning environments for the probabilistic literacy of students during their school years.</p> Francisco Rodríguez-Alveal, Danilo Díaz-Levicoy, Maitere Aguerrea (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15452 Mon, 14 Feb 2022 00:00:00 -0600 Emotions associated with the process of construction the parallelepiped volume https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15459 <p>This study analyzes the emotions of students between 14 and 17 years of age when they autonomously construct a rectangular box in 2D and 3D that represents the volume of a parallelepiped, using Cabri II Plus software. The methodology was based on frequency analysis using heat maps constructed with the Python computing tool. Using non-probabilistic sampling, and with the prior informed consent of their legal representatives, 34 ninth grade elementary school students were selected from a public educational institution in the city of Medellin, Colombia, of whom 28 participated in this study. Emotion was considered from a comprehensive point of view, taking into account its evolutionary, physiological-neural, cognitive, volitional and expressive aspects. FaceReader software, a specialized tool for detecting facial expressions, was used to capture these emotions. The results showed that, due to difficulties in the construction process, emotions such as sadness, anger, neutrality, fear, disgust and surprise were experienced. In the population studied, a correlation between emotional processing capacity and cognitive processing was detected. It was concluded that, when faced with difficulties in geometric construction that required drawing parallel lines and perpendicular lines, the difference between one point of intersection and another, and the relationship between the area or volume of a parallelepiped in 2D and 3D, negative emotions associated with the lack of mastery of these concepts emerged which, if students cannot exercise self control, can inhibit their cognitive processing, blocking their mental activities and leading them to abandon the task.</p> Fabricio Vladimir Vinces-Vinces, Juan David Giraldo-Rojas, Marcela Cecilia Parraguez-González, Luis Albeiro Zabala-Jaramillo (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15459 Mon, 14 Feb 2022 00:00:00 -0600 Inferential reasoning of high school mathematics teachers about t-Student statistic https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15788 <p>One of the topics that have been deeply studied in Statistical Education is that of how to promote formal inferential reasoning (FIR) based on the results of informal inferential reasoning (IIR). However, it is still necessary to have proposals to explore and progressively develop the inferential reasoning of students and teachers from IIR to FIR. In this context, this article seeks to characterize the inferential reasoning displayed by high school mathematics teachers in the practices they developed for solving problems about Student’s t statistic. To do this, we use theoretical and methodological notions introduced by the Onto-Semiotic Approach (OSA) to mathematical knowledge and instruction, among which are the notion of mathematical practice, mathematical object and the theoretical proposal of progressive levels of inferential reasoning about the Student’s t statistic. The subjects who participated in this qualitative study were 59 teachers in training from Costa Rica and 22 practicing teachers from Chile. The practices developed by the pre-service teachers and the practicing teachers were found to have similar elements (representations, concepts/definitions, properties, procedures, arguments). The principal conclusion of this investigation was that the proposal of inferential reasoning levels about Student’s t statistic proved to be a useful predictor of the practices developed by the teachers, making it possible to distinguish characteristic elements of each level of inferential reasoning.</p> Jesús Guadalupe Lugo-Armenta, Luis Roberto Pino-Fan (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15788 Thu, 10 Mar 2022 00:00:00 -0600 Technical skills in the professional practice of engineering in Costa Rica: A neuro correlation analysis https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14954 <p>The study is aimed at defining the correlations and affectation that the demographic variables of gender, age, and educational level have in the technical skills for engineering. The paper analyzes crossover data of a field study applied to a random probability sample of active engineers in Costa Rica.&nbsp; The theoretical bases needed for understanding the neurobehavioral factors to approach a given technical skill are defined and analyzed in an applicative manner based on crossed results and linked to the demographic variables of interest in the study subjects. To conclude, the paper studies multiple statistical correlations in terms of skills and demographic elements of interest such as educational level and age. Worth mentioning are the direct influences that age and educational level have on technical skills, with average coefficients amounting to 5.01% and 3.45%, respectively. In addition, an opposite correlation is observed in terms of skills such as mathematics and programming. A relationship of interest is established, in which technical skills seem to be directly related to the independent variables.</p> Juan Diego Sánchez-Sánchez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/14954 Wed, 01 Jun 2022 00:00:00 -0600 Analyzing students’ visual attention through spy glasses https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15783 <p>Visual attention is an important indicator in teacher-student interactions. This article presents the results of a study aimed to determine how the visual attention paid to the teacher by students fluctuates during their math and English classes and to detect possible differences in their attention.&nbsp; The study was conducted in a secondary school with a sample of 16 male students.&nbsp; Data was obtained by a mini video camera mounted on glasses wore by students. Using google images, we automatically and objectively analyzed 2613 frames from the recordings where the teacher appeared in the students’ visual field. Results show a difference in students’ visual attention between introvert and extrovert students throughout the 90-minute class. It was also observed that students were more visually engaged when the teacher's speech was accompanied by gestures. The paper highlights the importance of diversifying interactions that seek other ways to engage students in the last two-thirds of the class. Some implications for professional development programs are derived from this study.</p> Danyal Farsani, Jhony Alexander Villa-Ochoa (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15783 Wed, 01 Jun 2022 00:00:00 -0600 Teachers’ specialized knowledge through problem posing in pre-school education https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16218 <p>Problem posing, as a genuinely mathematical activity, provides an inexhaustible source of alternatives in a classroom. Many authors, as well as institutions such as the National Council of Teachers of Mathematics, highlight the importance of this mathematical practice. With this case study, we intend to demonstrate the characteristics of the type of knowledge used by a teacher when implementing this type of session in 4-year-olds, with an emphasis on the knowledge used for planning and putting the session into practice. We used fragments of the session’s recording, as well as a subsequent interview with the informant, in order to corroborate the information identified during the data analysis. The specific mathematical nature of this activity leads us to use the MTSK model (Mathematics Teachers’ Specialized Knowledge) as a reference to analyze the specialized knowledge that a pre-school teacher uses during a classroom practice. This practice is comprised of two tasks, both created and designed by the informant teacher. Results show aspects of knowledge related to MK (Mathematical Knowledge), but, above all, PCK (Pedagogical Content Knowledge) predominance, evidencing the importance of this type of knowledge in early childhood education to implement a problem posing session.</p> Juan Pedro Martín-Díaz, Miguel Montes (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16218 Wed, 01 Jun 2022 00:00:00 -0600 Cognitive analysis of probability comparison tasks by preservice primary school teachers https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16285 <p>To promote mathematical learning, teachers must be able to analyze, interpret and assess students’ mathematical activity, making decisions about their understanding of, and difficulties in, solving mathematical tasks. This cognitive analysis skill enables teachers to understand mathematical learning processes and to establish different ways of institutionalizing the mathematical knowledge involved. <strong>[Objective] </strong>This work is intended to present the results of an assessment of preservice Primary Education teachers’ knowledge and abilities to interpret students’ responses to probability comparison tasks, identify incorrect strategies and recognize proportional reasoning in mathematical activity. Furthermore, the strategies proposed by preservice teachers to help students overcome the difficulties that led them to obtain inadequate solutions are analyzed. <strong>[Methodology] </strong>Descriptive and qualitative research was carried out with the collaboration of 116 preservice Primary Education teachers from the University of Almería (Spain). The investigation was carried out once the process of training in the mathematical contents of Statistics and Probability had been completed. <strong>[Results] </strong>One of the most important results obtained is a didactic-mathematical knowledge of the type of proportional and probabilistic reasoning that impedes preservice teachers in their interpretation and decision-making about student responses. <strong>[Conclusions] </strong>These results highlight the need to implement educational solutions to adequately resolve these common situations in schools.</p> María Burgos, María del Mar López-Martín, Carmen Gloria Aguayo-Arriagada, Verónica Albanese (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16285 Tue, 01 Nov 2022 00:00:00 -0600 Towards a characterization of algebraic competence: an exploratory study with students https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15994 <p>[<strong>Objective</strong>] The present article seeks to determine the algebraic competence displayed by a group of 27 university students in Mexico when they worked on an algebraic problem. A study framework is proposed based on the investigation of mathematical competence and levels of algebrization&nbsp; in three areas: solving, interpreting and validating. [<strong>Methodology</strong>] A qualitative and exploratory study with convenience-based selection of students was implemented during a regular two-hour class. The professor and the researcher were present when the task was carried out in the classroom. [<strong>Results</strong>] The results show that the students had difficulties in problem solving because they did not effectively manipulate symbolic-literal expressions, and did not achieve the expected level of algebraization. They were also inconsistent in interpreting the task – that is, they did not identify or connect knowledge about the properties of the operations necessary to solve the algebraic problem. When validating their responses, they provided descriptive proofs or verifications. [<strong>Conclusions</strong>] The findings suggest that most of the participants did not display a basic level of algebraic competence, and the necessity of formulating stages of development based on the three actions is discussed.</p> Lilia P Aké, Carmen Olvera-Martínez (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/15994 Tue, 01 Nov 2022 00:00:00 -0600 Knowledge used by preservice teaching students when comparing areas of 2D figures https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16306 <p><strong>[Objective]</strong> This study seeks to characterize the specialized mathematical knowledge that preservice teachers make use of when solving tasks that involve comparison of areas of flat figures. <strong>[Methodology]</strong> Seventy (70) preservice teachers, in the third year of the Primary Education degree at the Universidad Autónoma de Barcelona during the period 2020-21, participated in the study. Preservice teachers answered a semi-structured open-ended questionnaire, which included eight tasks. A qualitative content analysis was carried out to analyze the procedures and justifications used by preservice teachers when solving two tasks. The analysis focuses on two of the subdomains of the Mathematics Teacher’s Specialized Knowledge model, Knowledge of Topics and of the Structure of Mathematics. <strong>[Results]</strong> The use of procedures related to the decomposition and reorganization of surfaces facilitates making use of categories of specialized knowledge, and establishing connections with other types of mathematical content. Furthermore, coordination of different registers of representation makes it possible to establish intra conceptual connections in the solution of the two tasks presented. <strong>[Conclusions]</strong> Representations, in their discursive and non-discursive registers, are presented as key indicators which assist in making explicit the procedures used by preservice teachers, and based on them, the justifications, properties and geometric principles that support the resolution process.</p> Sofía Caviedes, Genaro De Gamboa, Edelmira Badillo (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16306 Tue, 01 Nov 2022 00:00:00 -0600 Contrasts in the learning process among Forest Engineering students https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16187 <p><strong>[Objective]</strong> This study is focused on the analysis of learning styles and perceptions of university forestry engineering students at three different levels (beginning, intermediate and advanced). <strong>[Methodology]</strong> Tests were applied to determine students’ knowledge of topics related to the career, such as their perception of the career and topics or concepts that they considered to be complicated or problematic, all a using double-blind methodology with previously validated tests; a model of learning styles was subsequently developed. <strong>[Results]</strong> The results showed significant differences between beginning students and intermediate and advanced students. The group of beginners tends to be deficient in rote and meaningful learning, which improves as students advance in the program of study. In addition, it was determined that improvement in learning areas such as teamwork, soft skills and working under pressure increase students’ learning abilities. When the model was analyzed, it was determined that students’ expectations showed little relationship with the proposed model, regardless of the level of learning. Aspects such as prior knowledge and social influences significantly affect learning, which indirectly affects student satisfaction. <strong>[Conclusions] </strong>The proposed model is adaptable to forestry engineering students and helps them to better understand critical concepts and skills for the career; however, improvements must be made in the first stage of the program of study (for beginners) to reduce the need for memorization and promote learning through observational and discovery methods that would give students greater capabilities and motivation.</p> Juan Carlos Valverde, Mariela Romero-Zúñiga, Lupita Vargas-Fonseca (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16187 Tue, 01 Nov 2022 00:00:00 -0600 Transitions when adjusting interdisciplinary mathematical models: the case of financial literacy https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16426 <p><strong>[Objective]</strong> The objective of this research was to analyze the types of transitions in a modeling cycle that Chilean students performed in an interdisciplinary mathematical modeling task. <strong>[Methodology]</strong> To achieve this objective, a qualitative methodology was used, consisting of a case study in which a mathematical modeling task, based on the Blum-Borromeo modeling cycle, was implemented with 5 high school students from a private school in Chile. The task design incorporated components present in the curricula of History, Geography and Social Sciences, and Mathematics, and the four competencies proposed by OECD in terms of Financial Education. <strong>[Results]</strong> As a result of the research, it was found that students made 3 types of transitions in the modeling cycle, which were related to their level of financial literacy: the first transit, based on adjustments from the actual model; the second transit, based on adjustments from the actual results; and the third transit, based on adjustments from the actual model and the actual results. Based on these results, a discussion of students’ literacy levels is presented. <strong>[Conclusions]</strong> It was concluded that modeling tasks such as those discussed here are suitable environments for developing students’ levels of financial literacy.</p> Alejandro Cabrera-Baquedano, Jaime Huincahue, Claudio Gaete-Peralta (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16426 Tue, 01 Nov 2022 00:00:00 -0600 Cognitive and social skills in collaborative solution of mathematical problems https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16358 <p><strong>[Objective]</strong> The objective of this study was to analyze the cognitive and social skills of a group of students and their teacher in an exercise based on Collaborative Problem Solving (CPR) in Mathematics<strong>. [Methodology]</strong> A study was carried out by selecting one of the 8 groups of 4 students randomly assigned in a non-curricular exercise scheduled in 24 biweekly sessions of 90 minutes. The group selected consisted of 4 female students. The sessions were recorded, and data on the interactions between subjects (students and teacher) were coded at the beginning and at the end of the exercise for factors including skills of representation, regulation, communication and roles assumed in group work, and interaction with the teacher. The coded data were subsequently analyzed using asymmetric graph analysis techniques to measure the intensity of interactions, and correspondence analysis to determine the significance of relationships between the sub-skills involved. Rstudio software was used to carry out the analysis. <strong>[Results]</strong> A significant change in the intensity of interactions between participants was observed throughout the implementation with respect to the centrality and closeness indices associated with the graphs obtained. <strong>[Conclusions]</strong> The systematic CPR work in mathematics carried out in the exercise promotes and modifies social and cognitive skills and their interaction.</p> Eugenio Chandia, Anahí Huencho, Carlos Pérez, Andrés Ortiz, Gamal Cerda (Author) ##submission.copyrightStatement## http://creativecommons.org/licenses/by-nc-nd/4.0 https://www.revistas.una.ac.cr/index.php/uniciencia/article/view/16358 Tue, 01 Nov 2022 00:00:00 -0600