Principais Coleções do Repositório
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Um RPG eletrônico como recurso para o ensino de números reais no 9° ano do Ensino Fundamental em uma perspectiva histórica
(Universidade Federal de Lavras, 2025-09-30) Silva, Karina de Fátima Mesquita; Teodoro, Graziane Sales; Costa, Maria do Carmo Pacheco de Toledo; Fargnoli Filho, Helvécio Geovani; Vasconcelos, Lívia de Oliveira
This dissertation presents an investigation into the teaching of real numbers in the 9th grade of Elementary School through the integration of the History of Mathematics and the use of a RPG (Role-Playing Game). The study stems from the recognition that real numbers still represent an important challenge in the learning process of the students, especially when introduced in an exclusively formal manner. The main objective was to investigate the possible contributions that the relationship between historical narrative and interactive digital games can offer to the conceptual understanding of real numbers, particularly regarding the distinction between ratio- nal and irrational numbers. To achieve this purpose, a qualitative research study was conducted, involving the development of a teaching sequence based on the game titled The Guardian of the History of Mathematics: The Legacy of Numbers, authored by the researcher, and developed for pedagogical purposes. The teaching sequence was implemented in a public school in the south of Minas Gerais, with data collected through questionnaires, observations, and student productions. The analysis considered categories such as conceptual understanding, perception of the History of Mathematics, and evaluation of the game as a pedagogical resource. The re- sults revealed progress in the ability of the students to classify and distinguish between rational and irrational numbers, overcome recurring conceptual misconceptions, and relate real numbers to concrete situations. Greater engagement and motivation during the activities were also ob- served, fostered by the narrative and interactivity of the digital environment. Furthermore, the students recognized the History of Mathematics as an important element for understanding the origin and function of numerical concepts, attributing more meaning to the study of the content. Simultaneously, the proposal proved to be adaptable to other content areas, constituting a viable and innovative alternative for teaching Mathematics.
How effective soil depth modulatesimagery vegetation dynamicsin a semi-arid west african savanna
(Universidade Federal de Lavras, 2025-07-18) Muapizera, Saide; Menezes, Michele Duarte; Gomes, Felipe Haenel; Serafim, Milson Evaldo; Acerbi Junior, Fausto Weimar; Menezes, Michele Duarte de
Soil properties govern water availability and plant productivity, particularly in semi-arid environments. Soils with petroplinthic horizons can impose severe physical constraints on root growth, limiting the exploitable soil volume and influencing water drainage. However, the functional impact of this constraint and its interaction with different land-use systems remains poorly quantified. This study evaluated how effective soil depth shapes the seasonal and interannual dynamics of vegetation, using the NDVI as an indicator across land-cover types (cropland, grassland, and shrubland) in Bandiagara II, a plinthic landscape typical of the semi-arid Sikasso region in southern Mali. Field measurements of soil depth were integrated with a five-year (2019–2023) NDVI time series derived from Sentinel-2 imagery processed on the GEE platform. A GLM revealed a significant interaction (p < 0.01) between soil depth and land cover. In grasslands, the relationship was positive and significant (slope = +0.0032) and more pronounced in the dry season, whereas the trend in shrublands did not reach statistical significance. In contrast, NDVI in croplands showed no significant relationship with soil depth, suggesting that annual management practices can override the influence of this intrinsic edaphic property. The overall model explained 57% of NDVI variability (adjusted R2 = 0.569). The functional limitation imposed by a shallow petroplinthic contact is not uniform but depends fundamentally on vegetation type. These results provide a quantitative basis for local land-use planning and demonstrate the potential of DSM approaches integrating remote sensing to map functional edaphic constraints in data-scarce regions.
Associação da expressão de dois genes da família MATE com a tolerância ao alumínio em três espécies de Eucalyptus sp.
(Universidade Federal de Lavras, 2025-08-30) Martins, Mark Melo; Paiva, Luciano Vilela; Esteves, Giovana; Santos, Breno Régis; Paiva, Luciano Vilela
Eucalyptus is a crop of great importance to the market, as its processed wood supplies various production chains, such as paper and cellulose, charcoal and energy, and furniture. However, some species are affected by high concentrations of free aluminum present in the soil, reducing productivity. One of the main soil limitations is the presence of toxic aluminum, which becomes available to plants in soils with a pH below 5. In the Midwest, Southeast, and South regions of Brazil, where most eucalyptus plantations are located, this problem is common due to soil acidity. There is a family of genes called Multidrug and Toxic Compound Extrusion (MATE), which includes a group of proteins responsible for the exudation of organic acids in the roots. These proteins can release organic acids, such as malate and citrate, which can chelate phytotoxic aluminum and reduce its negative effects on plants. Given this, the aim of this study was to investigate and demonstrate the relationship between two genes from the MATE family and citrate exudation in three species of eucalyptus with different levels of tolerance to Al3+. For this purpose, seeds were germinated in vitro, and after 60 days, the seedlings of Eucalyptus grandis, Eucalyptus urophylla, and Eucalyptus dunnii were exposed to liquid media containing 2mM of Al3+ to stimulate citrate production and the activation of genes associated with this physiological response. Samples of the liquid medium were collected for analysis by High Performance Liquid Chromatography - Diode Array Detector (HPLC-DAD) and the enzymatic method for citrate detection using the Sigma-Aldrich® MAK333 Kit. The roots were collected, and total RNA was extracted, followed by DNase treatment to remove genomic DNA, cDNA synthesis, and primer efficiency testing for qPCR. Due to specific issues during the experiment, such as not being able to extract RNA with good quality indices, qPCR analysis, which would demonstrate gene expression under stressful conditions, was not possible. The enzymatic method for quantifying citrate release in the medium failed due to some interference from the medium where the explants were, such as pH or some component, Al3+ for example. However, the HPLC method worked, with some obstacles, to detect citrate concentrations in the medium, but the results did not show statistical variation. Therefore, it was not possible to prove the association of the candidate genes from the MATE family with Al3+ tolerance. However, the main points to be observed when conducting similar research were listed to avoid the same problems.
Seleção e atratividade de plantas medicinais para vespas sociais em sistema ecológico de cultivo
(Universidade Federal de Lavras, 2024-09-27) Noronha, Syara Cesario Bravo de; Carvalho, Geraldo Andrade; Silveira, Luís Cláudio Paterno; Carvalho, Geraldo Andrade; Silveira, Luís Cláudio Paterno; Carvalho, Alexandre Alves de; Jacques, Gabriel de Castro
In ecological planting systems, the application of pesticides is not performed, thereby promoting the maintenance of beneficial soil organisms, pollinators, and natural enemies. These systems utilize intercropping, including medicinal plants. Such plants perform biological functions, such as attracting pollinators and defending them against herbivores, due to their production of secondary metabolites, which can modulate the metabolism of other plants and insects. Integrated management strategies include the use of attractive plants that interfere with foraging behavior and the conservation of natural enemies, such as social wasps. Diverse cultivation can increase biodiversity, reduce the incidence of herbivorous insects, and maintain ecological balance. The present study aimed to develop a methodology for selecting potentially attractive medicinal plants for natural enemies to be cultivated in intercropping systems within ecological planting, focusing on conservative biological control and evaluating the attractiveness of medicinal plants to social wasps in an ecological environment. Scoring criteria were established for the pre-selected plants, considering favorable aspects and unfavorable characteristics, with each species assigned a positive, negative, or neutral score. The preliminary selection of plants for evaluation was based on local biodiversity, edaphoclimatic conditions, availability of plant species, and the presence of favorable metabolites. The methodology was applied, and the selected species were planted in 2022 and 2023 at the Agroecology Sector of IFSULDEMINAS, within the Atlantic Forest biome, characterized by Seasonal Semideciduous Forest physiognomy. The experiment included six treatments chosen from twenty medicinal species based on a literature review: Clinopodium sp. (Clinopodium); Lippia alba (Brazilian Lemon Balm); Petroselinum crispum (Parsley); Bidens pilosa (Black Jack); Coriandrum sativum (Coriander); and Tagetes erecta (Marigold), arranged in randomized blocks. Insects were collected weekly for nine weeks using an entomological net and pan traps and identified based on specific literature. Rarefaction curves, species richness (bootstrap and species), abundance, similarity, and variance analyses were conducted. For species richness, B. pilosa and L. alba exhibited the highest averages, significantly different from T. erecta and Clinopodium sp., while the other plant species showed intermediate richness averages. Significant differences were also observed for abundance, with the highest value recorded for B. pilosa, significantly different from T. erecta and Clinopodium sp., while the other plant species presented intermediate abundance values. Therefore, B. pilosa and L. alba are promising species for providing alternative resources to natural enemies when present in intercropping systems in ecological cultivation environments. The developed methodology can be adapted for other locations and objectives, depending on market interests and the areas of action of farmers and researchers. With the necessary adjustments, the methodology proved to be effective, as the highest-scoring plants were also the most attractive in the field.
Efeitos de uma multiprotease no desempenho, funcionalidade intestinal e digestibilidade em frangos de corte
(Universidade Federal de Lavras, 2025-08-22) Soares, Márcia das Neves; Bertechini, Antônio Gilberto; Pinheiro, Sarah Gomes; Kaneco, Isabelle Naemi; Fassani, Edison José; Silva, Vanessa Avelar
Multi-protease supplementation was evaluated for its effects on growth performance, carcass yield, intestinal morphology, microbiota, nutrient digestibility, and enzymatic activity in broiler chickens. Three experiments were conducted. In the first, performance, intestinal morphology, and microbiota were assessed in birds fed diets with reduced crude protein and amino acids levels (–4% and –8%) and supplemented with different enzyme doses (100, 200, and 300 g/t), using 2,250 broilers. The second experiment investigated the ileal digestibility of amino acids and the apparent metabolizable energy of corn, soybean meal, and deactivated full-fat soybeans, with or without protease addition (200 g/t), using 480 birds housed in metabolic cages. The third experiment evaluated in vitro the activity of four types of proteases (multi-protease, alkaline, acid, and neutral) at different pH values (3, 6, and 9), as well as the synergism between endo- and exo- proteases. Multi-protease inclusion significantly improved weight gain and feed conversion, positively modulated the intestinal microbiota by increasing the abundance of Firmicutes and Bacteroidetes, and enhanced intestinal morphology, particularly in diets with reduced amino acids. Protein and amino acid digestibility were significantly higher in enzyme-supplemented diets, especially for limiting amino acids such as methionine+cystine, lysine, threonine, and valine. Apparent metabolizable energy (AME and AMEn) was also increased with protease addition, particularly in diets containing deactivated full-fat soybeans. Enzyme activity varied according to protease type, pH, and concentration. Each enzyme performed best within its optimal pH range, with acid protease showing the highest activity at pH 3, neutral protease at pH 9, and alkaline protease exhibiting increasing activity up to pH 9. It is concluded that multi-protease supplementation is an effective strategy to improve productive performance, intestinal health, and nutrient utilization in broiler chickens, especially in diets with reduced crude protein and amino acid content.