Uniciencia

Structure and composition of a mangrove forest on the Central Pacific coast of Costa Rica: population of mollusks of commercial interest

Mon, 01 Jan 2024 00:00:00 -0600

[Objective]. The floristic composition and populations of associated molluscs of commercial interest of the Chacarita mangrove forest on the Central Pacific of Costa Rica were evaluated to guide proposals for sustainable exploitation activities in the mangrove forest. [Methodology]. Monthly visits to the study area were conducted for one year to establish a floristic baseline of mangrove trees and measure carbon storage. Additionally, bivalve molluscs were collected to analyze the state of their populations based on the abundances of organisms found, as well as other characteristics such as length and mass. Data regarding the mangrove trees included their diameter at breast height (DBH, cm), height (m), importance value index (IVI), and carbon reserves (Mg C·ha^-1). Four mollusc species of commercial interest were analyzed, using data on their length (cm), weight (g), and gonadosomatic index. Economic evaluations were also conducted using data obtained from the mangrove forest, as well as tourism and historical fishing data for the collection of Chacarita. [Results]. Five species of mangroves were identified: Rhizophora mangle, Rizophora racemosa, Laguncularia racemosa, Avicennia germinans, and Pelliciera rhizophorae, while P. rhizophorae had the highest importance value index. The study revealed a carbon storage equivalent to 78.49 Mg C·ha^-1. A total of 357 organisms were counted, with Anadara similis accounting for 18% of the total count, followed by Anadara tuberculosa (37.5%), Leukoma spp. (41.46%), and Mytella guyanensis (3.08%). When considering the economic value of carbon stocks and the bivalve molluscs obtained from the samples, economic valuations of 9,812.63 USD·ha^-1 and 28 USD·ha^-1were determined, respectively. [Conclusions]. The low population densities of molluscs, particularly those belonging to the Anadara genus, necessitate the establishment of management measures to facilitate the recovery of these mollusk populations. This research proposes sustainable use activities such as community tourism for educational and cultural purposes.

Potential for Saving Drinking Water Through the Use of Rainwater in Social Housing in Viçosa-Brazil

Mon, 01 Jan 2024 00:00:00 -0600

[Objective] The main objective of this research was to evaluate the potential for saving drinking water by using rainwater as a source of supply for non-potable purposes in two neighborhoods with social housing in the municipality of Viçosa, Minas Gerais, Brazil. [Methodology] The consumption statistics for each month of 2020 were used for each of the homes comprising the Benjamin José Cardoso and Sol Nascente Housing Complexes, and the fraction of drinking water that is destined in homes for non-potable purposes was estimated. The information corresponding to the monthly rainfall records of the last 50 years was analyzed and the monthly volume of rainwater that could be harvested in each house was calculated. [Results] The average monthly volume of rainwater that could be captured through the roof area of each dwelling is 3.39 m³. During the rainy months of the year, it would be feasible to save a higher percentage of water than that allocated for non-potable purposes. Sizing a rainwater reservoir that exceeds the monthly needs for non-potable purposes would allow the surplus of collected water to supply the liquid during the dry season. [Conclusions] Since the average percentage of savings in drinking water for both neighborhoods exceeded 53%, the saving of the monthly consumption can contribute to the reduction of payments for the drinking water service and the consumption of the liquid in the municipality, particularly during drought months.

Personal meanings in the formulation and argumentation of conjectures by high school students

Mon, 01 Jan 2024 00:00:00 -0600

[Objective] This paper discusses an investigation of the meaning of “conjecture” for secondary school students, and disparities between personal meanings and those acquired in a mathematical institution. [Methodology] The methodology used is qualitative. A case study was carried out to improve understanding of the personal meanings of conjecture to students in the initial years of secondary education in the city of Río Cuarto, Argentina (15-16 years old). The responses of a group of students to assignments including three problems that involve the creation, contrasting, reformulation and/or validation of conjectures were analyzed, including interviews with the students. These analyses were carried out using tools from the ontosemiotic approach, determining configurations of primary objects and cognitive processes in the students’ personal practices. [Results] It was possible to identify semiotic conflicts in these practices, particularly disparities between personal meanings of the concept of conjecture and the meaning intended to be imparted by the mathematical institution, providing empirical indicators of the epistemic value given by students to emerging propositions in their argumentation. This made it less likely that students would learn to doubt the scope of their initial statements and recognize the need to propose another type of argument, as was intended by the mathematical institution. [Conclusions] The results of this investigation showed the importance of revealing the ontosemiotic complexity of personal practices related to the formulation and validation of conjectures, and revealing the cognitive semiotic conflicts linked to personal meanings.

Didactic Suitability Assessment Guide of Educational Processes for the Differential

Manuel Alejandro Verón, Belén Giacomone, Luis Roberto Pino-Fan (Author) — Mon, 01 Jan 2024 00:00:00 -0600

[Objective] This article describes the process of preparing a Guide for the Assessment of Didactic Suitability of a process for studying the concept of the differential of a function. The objective of this exercise was to propose an instrument to promote, guide and support teachers’ analysis of, and reflection on, teaching and learning processes of the differential concept. [Methodology] The research method used was content analysis, and its starting point was a systematic review of didactic-mathematical knowledge in key research. The analysis was guided by the dimensions or facets that characterize an educational process – epistemic, cognitive, affective, instructional and ecological – whose components and criteria are based on the notion of didactic suitability proposed in the Onto-semiotic Approach to Mathematical Knowledge and Instruction (OSA). [Results] The construction of the Didactic Suitability Assessment Guide introduced a methodology for the reconstruction of the reference meaning for the study of various facets of the differential. In addition, this guide represents a powerful tool for teachers at the time of designing, implementing. and evaluating study processes, taking into account the various meanings of the differential, its connections, its potential semiotic conflicts and its relationships with other concepts. [Conclusions] In line with the theoretical reference framework, it is concluded that its ideal use would allow teachers to make informed decisions about management of the didactic process, taking into account its educational context.

Analysis of the School Climate Scale in University Environments (ECEAU)

Mon, 01 Jan 2024 00:00:00 -0600

[Objective] The aim of this paper is to verify the factorial structure of the School Climate Scale in University Environments (ECEAU) through structural equation models (SEM). [Methodology] A non-experimental cross-sectional study was carried out with a random sample of 381 students of the Universidad Nacional de Costa Rica (UNA), to whom the ECEAU was applied. A SEM model was proposed to confirm the factor structure of the scale and an exploratory factor analysis (EFA) was used to provide the basis for an alternative SEM model with a different structure. The reliability of scales was determined using McDonald’s omega, and the goodness of fit indexes used for the SEM models were the RMSEA, the CFI, the TLI and the GFI. The analysis was carried out using R software. [Results] The reliability of the scales in both models was adequate (w >0.70), although the metrics in the proposed model produced better results. The AFE suggested a different structure for the ECEAU, keeping some dimensions of the original structure and modifying and eliminating others. The goodness of fit indexes in both models were almost identical, with RMSEA=0.02, CFI=0.99, TLI=0.99 and GFI=0.98, which provides supporting evidence for the factorial structures proposed. [Conclusions] The original structure of the ECEAU was confirmed, while the differences in the results of the estimation and rotation methods generated another equally valid factorial structure for measuring the school climate construct in this university, and could be applied to other similar contexts.

Specialized Knowledge of Prospective Mathematics Teachers on the Concept of Mathematical Proof

Christian Roberto Alfaro-Carvajal, Jennifer Fonseca-Castro (Author) — Mon, 01 Jan 2024 00:00:00 -0600

[Objetivo] En este artículo, se presentan los resultados de una investigación cualitativa de carácter descriptivo que tiene como objetivo caracterizar el conocimiento especializado de los profesores de matemáticas en formación inicial de la Universidad Nacional en Costa Rica (UNA), sobre el concepto de la demostración matemática, mediante el modelo Mathematics Teacher’s Specialized Knowledge (MTSK). [Metodología] La investigación se posiciona en el paradigma interpretativo y tiene un enfoque cualitativo. Se aplicó un cuestionario, durante el primer semestre del 2021, a 42 profesores de matemáticas en formación inicial de cuarto y quinto año de la carrera Bachillerato y Licenciatura en Enseñanza de la Matemática de la Universidad Nacional de Costa Rica. Para examinar la información, se empleó el análisis de contenido y se hicieron agrupaciones de las respuestas, con el propósito de generar ideas centrales sobre el concepto de demostración. [Resultados] De los resultados se desprenden cuatro ideas centrales sobre lo que es una demostración matemática para los sujetos de la investigación, cercanas a aspectos formales lógico-sintácticos y matemáticos (ALSM) o aspectos informales semánticos (AIS). Se encontraron evidencias de las cinco funciones de De Villiers (1993) para la demostración y surgieron nuevas funciones relacionadas con esta en las matemáticas y en las matemáticas escolares. [Conclusiones] Los resultados brindan insumos a formadores de profesores de matemáticas e investigadores, en la revisión y análisis de programas de formación docente, y contribuyen en la búsqueda de nuevas áreas de investigación relacionadas con el tema.