Principais Coleções do Repositório
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Linguagem matemática e língua materna: aproximação para uma aprendizagem significativa
(Universidade Federal de Lavras, 2025-12-19) Mota, Bernadete A. de Oliveira; Goulart, Ilsa do Carmo Vieira; Andrade, José Antônio Araujo; Gazire, Eliane Scheid; Assis, Eliasaf Rodrigues de
The research highlighted the importance of developing literacy skills in the Mother Tongue (MT) and in Mathematics for the full development of students. It emphasizes that literacy is not limited to alphabetization, but rather permeates all aspects of teaching and learning, involves social practice, and broadens the understanding of the world in its diverse cultural manifestations. Based on data from the Programme for International Student Assessment (PISA), which indicate low proficiency among Brazilian students in these areas, the need for effective actions to improve teaching and learning was evident, and the importance of the interrelation between MT and Mathematics was recognized. Given this problem, the objective was to understand how the teaching of MT and Mathematics approached in the literacy process, considering teachers' conceptions, pedagogical practices, and the formative conditions that influence it. As a theoretical basis, it relied on discussions that relate literacy in Mathematics and in MT as complementary processes presenting similar characteristics from a literacy perspective. Therefore, as a methodological approach, exploratory field research was adopted, with a quantitative-qualitative approach, using Likert-type questionnaires via Google Forms and semi-structured interviews as instruments, with literacy teachers from elementary schools (early years) in municipal schools in a city in the southwest region of Minas Gerais. To examine the data collected, description, content analysis, and integration/cross-referencing techniques used. The results indicate that the approximation between the teaching of the mother tongue and mathematics favors the construction of meaning, the mobilization of students' prior knowledge, and contributes to overcoming learning difficulties observed in both subjects. They highlight the importance of teacher training as a central axis so that teachers can understand, plan, and implement pedagogical proposals that bring mathematics and the mother tongue closer together. As an educational product, a Pedagogical Workshop was conducted with volunteer teachers from one of the schools in the municipal network, focusing on the articulation between curricular components through communication, the valuing of collaborative work, conceptual and pedagogical improvement, and the re-signification of pedagogical practices. It concluded that the approximation between mathematical language and the mother tongue enhances the literacy process, promoting contextualized and meaningful learning.
Development and characterization of biodegradable films from xanthan gum/polyvinyl alcohol polymeric blends reinforced with cellulosic nanostructures for food packaging applications
(Universidade Federal de Lavras, 2025-12-17) Costa, Maria Rita Meyer Ferraz da; Guimarães Junior, Mário; Sanadi, Anand Ramesh; Oliveira Junior, Enio Nazaré de; Dias, Marali Vilela; Moreira Neto, João; Patricio, Patricia Santiago de Oliveira; Oliveira, Taíla Veloso de; Oliveira, Taíla Veloso de; Thybring, Emil Engelund; Yoshida, Cristiana Maria Pedroso
Biodegradable polymers are a class of materials that have emerged as an alternative to mitigate environmental issues caused by the use and improper disposal of petroleum-derived polymers. In this context, the development of new materials based on more efficient and sustainable technologies has intensified, aiming to replace synthetic plastics. However, the production of biodegradable materials still faces limitations, mainly due to high manufacturing costs and inferior thermo-mechanical and barrier properties against gases and moisture. A viable strategy to overcome these limitations is the use of polymer blends, which allow the tailoring of material properties to meet specific demands. This approach shows great potential for applications in various sectors, especially in the production of flexible packaging. In this context, the present study aimed to produce and characterize flexible films based on xanthan gum (XG) and polyvinyl alcohol (PVA), using the solvent evaporation method. Xanthan gum was produced in the laboratory via submerged fermentation from sugarcane bagasse, an agro-industrial residue, using the bacterium Xanthomonas campestris CCT5268. The resulting biopolymer yielded 2 g/L, exhibited pseudoplastic behavior (apparent viscosity of 135 mPa·s at 25 °C and 25 s⁻¹), a molar mass of 1,238,000 kDa, and thermal resistance up to 300 °C, values slightly superior to those of commercial gum. FTIR analyses revealed characteristic absorption bands of polysaccharides, indicating structural similarity between the samples. Polymeric blends developed with commercial XG and lab-produced gum (XGL) showed significant improvements compared to the PVA control film, such as reduced thickness and maintained thermal stability (200 °C for PVA/XG and 195 °C for PVA/XGL). The PVA/XGL1 blend stood out with a tensile strength of 34 MPa, elongation of 270.97%, water vapor permeability of 0.243 g·mm/m²·h·kPa, and a contact angle of 80.81°, indicating greater hydrophobicity and polymer compatibility. Subsequently, the films were enhanced by incorporating cellulose nanofibrils (CNF) into mono- and bilayer films, along with corona treatment applied to bilayer systems. CNF incorporation increased tensile strength to 46.57 MPa and improved thermal stability (348.6 °C) in monolayer films. In bilayer films without corona treatment, increased stiffness (Young’s modulus of 1679.64 MPa), tensile strength of 48.11 MPa, and a significant reduction in flexibility (elongation of 37.79%) were observed, indicating lower interfacial compatibility between layers. Solubility was 9.80%, and opacity increased, with 85% transmittance, features favorable for packaging light- and moisture-sensitive foods. In bilayer films with CNF and corona treatment, a significant improvement in flexibility (elongation of 158.88%), reduced solubility (8.10%), and increased opacity (transmittance of 78.05%) were observed. These modifications indicate enhanced interfacial adhesion and improved functional performance. The results obtained across the three studies demonstrate the technical feasibility of producing xanthan gum from agro-industrial residues and its application in advanced polymer systems. The combination of PVA and XG, reinforced with CNF and surface-modified via corona treatment, resulted in biodegradable films with functional properties suitable for sustainable packaging, contributing to waste valorization and reduced environmental impact.
Poluição além do visível: microplásticos em ecossistemas lênticos tropicais e seus fatores ecológicos determinantes
(Universidade Federal de Lavras, 2025-09-29) Binler, Natasha Ferreira Valsoni; Bueno, Alessandra Angélica de Pádua; Hernández, John Jairo Arévalo; Pompeo, Paulo dos Santos; Benone, Naraiana Loureiro
Microplastic (MP) pollution represents an emerging threat to the integrity of aquatic ecosystems, particularly in tropical lentic environments that remain poorly studied. This study investigated the occurrence, distribution, and ecological drivers of MP abundance in sediments and marginal soils of tropical artificial lagoons located at the Federal University of Lavras (UFLA), Minas Gerais, Brazil. An initial methodological validation step was conducted for MP extraction, in which sediment samples of different textures were sequentially processed through: (1) organic matter digestion; (2) density separation using water (H₂O), sodium chloride (NaCl), and zinc chloride (ZnCl₂) solutions; (3) filtration; and (4) optical microscopy analysis, including morphological characterization of particles (shape, color, and size). The most efficient methodology was then applied to environmental samples. Environmental and anthropogenic variables (visible plastic debris, soil texture, surrounding land use, hydrological position, and distance from roads) were incorporated into statistical models to identify factors associated with MP abundance. The protocol achieved an average recovery efficiency of 87.2%, with higher rates in sandy sediments and the best performance observed with ZnCl₂ among the tested solutions. MPs were detected in 100% of environmental samples, totaling 9,244 particles and an average abundance of 14,006 ± 17,043 particles·kg⁻¹. The composition was dominated by fragments (73.2%), black particles (81.9%), and sizes <500 µm (94.7%). Although no significant differences were found between margins and lagoon bottoms, high spatial variability was observed across lagoons, with concentrations exceeding 30,000 particles·kg⁻¹ in some and falling below 8,000 in others. Principal component analysis revealed distinct patterns in particle composition among lagoons, suggesting different sources and depositional processes. Regarding hydrological connectivity, lagoons closer to headwaters exhibited higher abundances, whereas more distant or disconnected ones showed reduced values, indicating a filtering effect of hydrological flow. Statistical models identified forest cover (positive relationship) and visible plastic debris mass (negative relationship) as the main predictors of MP abundance. The results confirm that apparently preserved environments, such as headwater areas with greater forest cover, are not free from contamination, possibly due to diffuse inputs such as atmospheric deposition. Conversely, the absence of visible macroplastics did not indicate low contamination, suggesting that visually “clean” sites may conceal high loads of microscopic particles. The predominance of small, dark fragments highlights ecological and health concerns, given their high bioavailability to aquatic organisms and potential for trophic transfer. Overall, tropical lagoons act as important sinks for MPs, reflecting the interaction between anthropogenic and environmental factors. This study helps to fill knowledge gaps on MP pollution in freshwater ecosystems, providing insights for monitoring, mitigation, and public policies aimed at waste management and water quality conservation.
Consciência fonológica na alfabetização: contribuições para apropriação do sistema de escrita alfabética
(Universidade Federal de Lavras, 2025-12-02) Berg, Josiane Valéria Pereira; Vieira, Mauriceia Silva de Paula; Rocha, Juliano Guerra; Martins, Raquel Márcia Fontes
Studies show that phonological awareness, the ability to reflect on the sounds of speech, assists in understanding the phoneme-grapheme relationship, one of the skills required for literacy. Based on this assumption, this research proposes the following question: In what ways is work with phonological awareness developed and explored in the pedagogical practices of first-grade teachers in the context of literacy? The general objective of this research is to investigate teachers’ perceptions of phonological awareness and the ways in which this skill is developed in the classroom. As specific objectives we pretend to: (i) to investigate teachers’ perceptions of phonological awareness; (ii) to map pedagogical strategies and resources used by teachers for the development of phonological awareness in the classroom; and (iii) to analyze evidence of students’ progress in the acquisition of alphabetic writing. The theoretical framework was based on the studies of Morais (2012, 2019), Rigatti-Scherer (2020), and Soares (2004, 2016, 2020). Methodologically, this is an exploratory study with a quali-quantitative approach, conducted with four literacy teachers and 30 first-grade students from a public school. Data collection involved structured interviews with the literacy teachers, classroom observations, and the administration of diagnostic writing assessments at two different moments. The interview analyses showed that literacy teachers advocate for a systematic approach to phonological awareness and argue that it contributes to the development of alphabetic writing. In students’ performance, progress was observed in their stages of writing. It is concluded that phonological awareness is a necessary skill for the acquisition of reading and writing; however, for this to occur, planned, systematic, and intentional teaching practices are required.The educational product, in the form of an ebook, proposes activities that link theory and practice, combining playfulness and systematization in the development of syllabic awareness.
(Multi)letramentos e práticas de leitura : a compreensão de textos multissemióticos no contexto do Ensino Fundamental
(Universidade Federal de Lavras, 2025-12-05) Dias, Lídia Regina; Vieira, Mauriceia Silva de Paula; Ferreira, Helena Maria; Paris, Larissa Giacometti
Teaching reading in contemporary times is a challenging process, since the texts that circulate socially present various semiotic resources (verbal, static or non-static images, sounds, colors, among others) that contribute to the construction of meaning. This research is based on the premise that reading is a social language practice to be learned and, for learning to occur, explicit and systematized teaching is necessary. From this perspective, with this work, we seek to answer the following question: What is the performance of second-grade students in Elementary School – Early Years – in relation to the reading and comprehension of multisemiotic texts? The general objective that guided us during this research was: To analyze the performance of students from three second-grade classes in Elementary School – Early Years – in relation to the reading of multisemiotic texts. As specific objectives we sought to: a) analyze how reading practices are developed by three teachers in the second grade of Elementary School, in relation to multisemiotic texts; b) to analyze the performance of students from three second-grade classes in Elementary School – Early Years in relation to reading skills of multisemiotic texts of different textual genres; c) to reflect on reading strategies that can contribute to the formation of readers; d) to produce an e-book aimed at teachers that addresses work with multisemiotic texts. Methodologically, this research presents a literature review to theoretically support the study, in addition to the collection of primary data gathered through field research, carried out through two practical activities developed with second-grade Elementary School students, in order to assess their level of comprehension of multisemiotic texts. We also conducted interviews with teachers of the same grade level to understand how work with these texts is planned and developed. The analyses revealed that, although the teachers recognize the importance of working with multisemiotic texts, they still encounter challenges in the implementation and application of pedagogical practices, as well as in defining the theoretical and methodological basis that supports work with the reading of multisemiotic texts. The data generated by the analysis of the "Diagnostic Activity" revealed that students have greater difficulty in interpreting texts of the poster and comic strip genres. Examining the data generated by the activity "Reading and interpreting the Vivo Brincar campaign," we observed that students were more skilled at identifying explicit information in multisemiotic texts, while the practice of inference and the identification of implicit information proved more challenging. As an educational product, we present an e-book containing activities focused on working with multi-semiotic texts. We aim to strengthen the relationship between theory and practice, considering the real conditions of the classroom in order to contribute to the development of efficient educational practices as a basis for the implementation of measures that value, promote, encourage and strengthen teaching and practices aimed at the formation of readers.