https://repositorio.utem.cl/handle/30081993/1364 2026-04-14T15:46:07Z 2026-04-14T15:46:07Z Vergaño-Salazar, Juan Gabriel Velásquez, Nelson A. Córdova-Lepe, Fernando https://repositorio.utem.cl/handle/30081993/1385 2023-06-05T16:23:27Z 2023-04-01T00:00:00Z

Persistence condition on mobility parameters for obligate-migration populations. Vergaño-Salazar, Juan Gabriel; Velásquez, Nelson A.; Córdova-Lepe, Fernando Animal species change their residence places due to the high temporal variability in the availability of resources. Thus, animals move to sites with higher productivity and they search environments with the necessary resources that allow it to develop the different stages of their life cycle. Here, we present a simple mathematical model that determines a no extinction condition (stable oscillation) in terms of the movement parameters for obligate-migration populations. We understand the obligate-migration as a movement seasonally predictable in distinct locations, which is associated with patterns of resource distribution. Pág. 27 – 34, gráficos, tablas, fórmulas.

2023-04-01T00:00:00Z Sobetska, Olha https://repositorio.utem.cl/handle/30081993/1384 2023-06-05T16:10:41Z 2023-04-01T00:00:00Z

Relevance of Null Hypothesis Significance Testing (NHST) in biomedical sciences: sociological approach. Sobetska, Olha Significance tests play a very important role in the scientific community, and the biomedical research community is not an exception. This is due, on the one hand, to the widespread use of the test in scientific methodology and the corresponding frequency of its application in research, and, on the other hand, to the general misinterpretation of the results obtained using this method. Misunderstanding of significance testing in academia and erroneous conclusions in research, regardless of the scientific field, are at the root of the distrust of this statistical method. This article aims to give insight into the relevance of this kind of method in the biomedical field and find a theoretical explanation for this phenomenon, and subsequently regulate the correct interpretation of the null hypothesis significance test (NHST), as well as consider alternative statistical methods. In addition, some relevant empirical studies from a geographical and multidisciplinary perspective will be presented to determine the real extent of misspecification at the academic level. In this way, both practical and theoretical arguments will be applied to address the problem of NHST at multiple levels. Pág. 13 – 21, gráficos, tablas. Anexo: Proposal of the questionnaire (4 hojas.)

2023-04-01T00:00:00Z Cássia da Cunha, Amanda de Momo, Fernando Roberto Reganhan Coneglian, Cassiana Maria Catapani Poletti, Elaine Cristina https://repositorio.utem.cl/handle/30081993/1383 2023-06-05T15:54:09Z 2023-04-01T00:00:00Z

Mathematical model as a management tool to analyze organic matter self-purification in reservoirs. Cássia da Cunha, Amanda de; Momo, Fernando Roberto; Reganhan Coneglian, Cassiana Maria; Catapani Poletti, Elaine Cristina A mathematical model to analyze the self-purification potential of organic matter in reservoirs was developed, seeking to constitute a potential water management tool for easy application. Therefore, it was considered the input of organic matter into the watercourse, its sedimentation, decomposition and its output downstream, as well as the oxygen input through the flow and through re-oxygenation, its consumption by microbial activity and its downstream exit. The model was validated using data of Tietê river and applied using data of Salto Grande reservoir, both located at São Paulo State, Brazil, considering different scenarios of biochemical oxygen demand (BOD), dissolved oxygen (DO), water inlet flow and reservoir water volume. The results show that organic matter is decomposed faster in the first 12 hours of water travel; moreover, self-purification efficiency is better with a greater volume of water in the reservoir. The model is quite representative to study different self-purification scenarios in dammed areas, concluding that the developed model, being tested and improved, can already contribute to the management of reservoirs, with the advantage of having a simple application. Pág. 1 – 12, gráficos, tablas, imágenes.

2023-04-01T00:00:00Z Mejías Caballero, Wilson https://repositorio.utem.cl/handle/30081993/1382 2023-06-05T14:36:28Z 2023-04-01T00:00:00Z

Estudio de un modelo predador-presa con tres especies y capacidad de carga variable. Mejías Caballero, Wilson This research focused on the study of an ecosystem in which two predators, Puma concolor and Lycalopex culpaeus, coexist and compete for common prey. This model also includes that the Puma preys on the Culpeo fox, which adds dynamic to the system. Differential equations were used to model the interaction between these three species, considering the variable carrying capacity of prey and assuming no migration or external predation. 256 simulations were performed using different parameter values, and various scenarios were found where both predator species became extinct, exclusive extinction of either the Puma or the Culpeo fox occurred, and situations where the excessive growth of a predator led to a decrease in prey population and therefore extinction of the entire system. The results showed that the consumption rate of predators is one of the factors that most regulate the system’s behavior. It was also observed that the change in the trend of carrying capacity affected the maximum densities of prey that could be achieved. Pág. 35 – 41, gráficos, tablas, fórmulas.

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