Principais Coleções do Repositório
Submissões Recentes
Efeitos da suplementação aguda e crônica de nitrato no desempenho físico de mulheres praticantes de exercícios resistidos
(Universidade Federal de Lavras, 2025-12-16) Lares, Igor Santos; Maciel, Luiz Henrique Rezende; Silva, Sandro Fernandes da; Couto, Elizandra Milagre
Introduction: Nitrate (NO3-), a dietary anion abundant in vegetables, is metabolized into nitrite (NO2-) and subsequently into nitric oxide (NO), increasing its plasma bioavailability. The growing interest in improving performance in resistance training has led people to seek nutritional supplements. This makes NO3-, with its potential physiological effects, improved mitochondrial efficiency, decreased oxygen cost, and enhanced vasodilation, a viable option. Justification: Although NO3- has shown positive results, especially in aerobic exercise, the literature lacks studies that consistently evaluate its effect in resistance training (RT). Furthermore, there is a lack of studies in female populations and in complete training sessions of longer duration. Objective: To evaluate the effect of acute and chronic NO3- supplementation on physical, hemodynamic, and psychophysiological factors in women practicing resistance training. Methodology: A randomized, double-blind clinical trial, approved by the Ethics and Research Committee (CAAE: 67603023.0.0000.5148), included 21 participants (age: 22.30 ± 2.87; body mass = 60.80 ± 8.01) divided into two groups: nitrate group (NG) (n = 11) and placebo group (PG) (n = 10) – all with experience in RT. Four in-person visits were conducted. In the first phase, familiarization was carried out, including physical and nutritional assessments, as well as measuring the loads to be used in the following days and signing the Informed Consent Form (ICF) and the Image Release Form (IR). In the second phase, the first experimental test was conducted without supplementation. The data collected were heart rate (HR), mean arterial pressure (MAP), and double product (DP) at rest and after the end of each exercise and 5 minutes after the end of the test session. Lactate levels at rest and at the end of the test, the number of repetitions on the leg extension machine, the pre-test and 5 minutes after the end of the last exercise isometric voluntary contraction (IVC) test, and the rating of perceived exertion (RPE). On the 3rd and 4th visits, the same protocol was followed with the intervention of acute and chronic supplementation, respectively. For statistical analysis, a two-way ANOVA test was performed to compare the conditions, with a significance level of p < 0.05. Results: An increase in repetitions was observed in both groups throughout the tests (p < 0.003). Despite the intra-group improvement over time, there were no differences between nitrate and placebo in any variable analyzed. Conclusion: Nitrate supplementation did not promote ergogenic effects on physical performance, lactate, RPE, and hemodynamic factors in women practicing resistance exercise. This suggests that the effects may depend on the type of exercise and the individual's physiological characteristics. Further research with greater control over the menstrual cycle and plasma concentrations of NO2- and NO is recommended for a better understanding of the results.
Oportunidades e desafios profissionais para jovens com altas habilidades: estudo com os egressos do Centro para Desenvolvimento do Potencial e Talento (CEDET) - Lavras-MG
(Universidade Federal de Lavras, 2026-02-24) Silva, Raphael Alex; Cabral, Eloisa Helena de Souza; Silva, Bethania Bittencourt Costa e; Alcantara, Valderi De Castro
This study examines the trajectories of graduates from the Center for the Development of Potential and Talent (CEDET) in Lavras, Brazil, focusing on their access to higher education and integration into the labor market. Framed within the scope of Special Education policies for students with Giftedness and High Abilities (GHA), the research adopted a mixed, qualitative and quantitative, and exploratory approach, combining questionnaires administered to graduates with semi-structured interviews conducted with the center’s facilitators. The objective was to understand to what extent CEDET’s educational experience influenced academic and professional decisions and the construction of life projects. The findings reveal consistent effects, such as a high rate of access to higher education, strong occupational insertion, and diversification of fields and professional affiliations, accompanied by gains in self-knowledge, autonomy, and vocational clarity. Evidence indicates that individualized plans, hands-on experiences in workshops, laboratories, and projects, combined with mentorship, operate as key mechanisms mediating the relationship between interest and opportunity, reducing barriers typically observed in the transition from youth to the workforce. As a technical product, an educational guide was developed to support students with GHA in exploring career areas, planning their studies, and managing their professional transition. It is concluded that CEDET represents an exemplary public policy in talent development and educational equity, providing replicable insights for educational networks seeking to integrate academic training, socioemotional development, and entry into the world of work. Keywords: giftedness and high abilities; special education; public policies; professional insertion; CEDET.
Otimização da montagem de elenco no futebol : aprendizado de máquina para redução da imprevisibilidade em contratações
(Universidade Federal de Lavras, 2026-03-23) Nunes, Lucio Vargas de Albuquerque; Pereira, Dilson Lucas; Moreira, Mayron César de Oliveira; Valle, Cristiano Arbex
Football, the most popular sport in the world, is marked by a high degree of unpredictability, which makes squad building, tactical planning, and player selection particularly challenging. This study explores the use of Machine Learning (ML) and Operations Research (OR) techniques as decision-support tools in the sports context. The objective is to develop a predictive model capable of estimating club performance based on individual player statistics. These predictions are then used as inputs for optimization algorithms aimed at guiding player recruitment strategies, enabling more efficient and data-driven decisions. This approach seeks to reduce subjectivity in sports management processes, promoting greater accuracy in market decisions and contributing to a more strategic, evidence-based decision-making framework within football clubs. Keywords: football; machine learning; operations research; sports analytics; squad building
Ecological risk assessment and soil quality in areas impacted by iron mining tailings deposition
(Universidade Federal de Lavras, 2025-12-12) Reis, Tamires Rodrigues dos; Carneiro, Marco Aúrelio Carbone; Marques, João José Granate Sá e Melo; Botelho, Soraya Alvarenga; Alves, Paulo Roger Lopes; Nunes, Márcio Renato
The failure of the Fundão tailings dam in 2015 in Mariana (Minas Gerais, Brazil) released millions of cubic meters of iron mining tailings that dispersed along the Doce River basin, affecting terrestrial ecosystems. Despite the extensive documentation of the initial impacts, uncertainties remain regarding how the deposition of these tailings’ influences, in the medium term, soil organisms and the biological processes responsible for maintaining the ecological functioning of affected soils. In this context, this thesis investigated how the deposition of mining tailings influences soil chemical, physical, and biological attributes and how these alterations are reflected in the response of soil organisms to environmental stressors and in ecological risk assessment in soils with tailings deposition eight years after the dam failure. To address this objective, the thesis was structured into three complementary studies. In the first study, the toxicity of tailings alone and the response of standardized soil organisms to exposure to tailings combined with a pesticide were evaluated in soils with tailings deposition and in reference soils. The test organisms used were Folsomia candida, Enchytraeus crypticus, and Eisenia andrei. The results indicated that the tailings alone produced low ecotoxicological effects on the evaluated species. However, when the pesticide was applied, greater sensitivity of the species was observed in soils with tailings deposition compared with reference soils, indicating that biological responses to contaminants may vary depending on soil characteristics. In the second study, soil biological processes and the structure of soil organism communities associated with the maintenance of ecological functioning were investigated. Three lines of evidence were integrated: physical, chemical, and biological. Soils with tailings deposition showed higher pH, greater bulk density, and enrichment in Fe and Mn. From a biological perspective, reductions exceeding 50% were observed in microbial biomass, basal respiration, and enzymatic activities. The mesofauna community showed structural simplification, characterized by reduced diversity and the predominance of Hymenoptera. In the third study, an integrated Ecological Risk Assessment (ERA) approach based on the Dutch Triad model was applied, traditionally structured around chemical, ecotoxicological, and ecological lines of evidence. As a methodological innovation, a fourth line of evidence based on soil physical attributes was incorporated. Although the integrated risk derived from the chemical assessment was classified as low due to the low concentrations of potentially toxic elements, the ecological and physical lines of evidence indicated relevant alterations in soil properties, including compaction, reduced porosity, and low microbial biomass. Soil Quality Index (SQI) values corroborated these findings and showed that alterations in physical attributes may help explain the effects observed in other system components. Overall, the results demonstrate that even eight years after the dam failure, soils with tailings deposition still exhibit persistent alterations in physical and biological attributes associated with soil ecological functioning. These findings indicate that assessments based exclusively on chemical parameters may underestimate persistent ecological alterations in areas affected by mining tailings. Incorporating soil physical attributes into integrated environmental assessment approaches contributes to a more robust interpretation of the processes regulating ecological functioning and recovery in these systems. Keywords: soil ecosystems; mining tailings; ecological risk; soil quality; soil fauna; microbial activity
Gestão de recursos de uso comum sob a ótica da teoria da ação comunicativa
(Universidade Federal de Lavras, 2026-03-26) Carmo, Gisleine do; Pereira, José Roberto; Rezende, Vânia Aparecida; Cabral, Eloisa Helena de Souza; Alcântara, Valderí de Castro; Tonelli, Dany Flávio; Oliveira, Lucas Canestri de
The management of common-pool resources has received increasing attention in the field of Administration and the Social Sciences. Elinor Ostrom’s Common-Pool Resource Theory demonstrated that communities can develop their own institutional arrangements to collectively manage their goods effectively, without relying exclusively on the state or the market. However, the theory remains underdeveloped regarding the processes of constructing, legitimizing, and revising the norms that support self-governance. To address this gap, this dissertation proposes a theoretical expansion based on Jürgen Habermas’s Theory of Communicative Action, seeking to answer the following question: How can Elinor Ostrom’s Neo-institutional Theory of Common-Pool Resource management be expanded to incorporate communicative action, from a Habermasian perspective, in order to explain the process of constructing legitimate norms that can solve collective problems? The general objective was defined as follows: to analyze the process of elaborating norms, and their forms of legitimation and validation, aimed at solving collective problems, through the expansion of Elinor Ostrom’s Common-Pool Resource Theory grounded in Habermas’s Theory of Communicative Action. The specific objectives were: i) to critically review Elinor Ostrom’s Common-Pool Resource Theory, with emphasis on the construction, adaptation, and legitimation of norms that sustain self-governance; ii) to analyze empirical evidence on commons management through the lens of Ostrom’s theory, focusing on processes of norm construction and legitimation; iii) to propose a theoretical model integrating Habermas’s Theory of Communicative Action with Ostrom’s Common-Pool Resource Theory, highlighting the role of communication in the creation of legitimate norms and in the sustainability of self-governance. This dissertation is theoretical in nature and structured in three parts. First, a systematic review of Elinor Ostrom’s work was conducted, identifying her main contributions as well as analytical gaps related to the absence of an emphasis on intersubjectivity, deliberation, and normative legitimacy. Next, a qualitative metasynthesis of empirical studies applying Ostrom’s Common-Pool Resource Theory was developed, revealing that, in practice, the success of self-governance is often associated with communicative processes such as negotiation, consensus-building, mutual recognition, and rule revision emerging from public spheres. Finally, a theoretical construction was developed, resulting in the model of Deliberative Commons Governance. This model complements the reformulation of the IAD framework (deliberative IAD) and the expansion of the design principles, proposing a communicative reorganization of commons self-governance and distinguishing two analytical moments: the pre-institutional moment, in which norms emerge from public deliberation, and the post-institutional moment, in which they are legitimized and reformulated when necessary. By repositioning communication as a central element of institutional analysis, this dissertation contributes to a more critical and reflective understanding of commons self-governance, offering a theoretical model that expands Elinor Ostrom’s approach. Keywords: common; common-pool resources; Elinor Ostrom; self-government; collective action; communicative action