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Artigo
Quasilinear approximation for interval-valued functions via generalized Hukuhara differentiability
(2022-04-20) Osuna-Gómez, R.; Costa, T. M.; Chalco-Cano, Y.; Hernández-Jiménez, B.
In this paper, a new generalized Hukuhara differentiability concept for interval-valued functions defined on Rn is proposed, which extends the classical Fréchet differentiability notion and provides an interval quasilinear approximation for an interval-valued function in a neighborhood of a point at which such function is gH-differentiable. Moreover, it overcomes the shortcomings generated by the use of the gH-differentiability concept previously presented in the literature, and this presents a good perspective on interval and fuzzy environments. Several properties of this new concept are investigated and compared with the previous concept properties. Furthermore, the gH-differentiability concept is extended for a fuzzy function, and its introduction is argued and illustrated with examples.
dissertação
Isótopos estáveis de carbono em anéis de crescimento como proxies climáticos em floresta tropical sazonalmente seca
(Universidade Federal de Lavras, 2026-02-13) Sousa, Kaick Coelho de; Barbosa, Ana Carolina Maioli Campos; Pereira, Gabriel de Assis; Bianchi, Maria Lucia
Isotopic dendrochronology, which links the study of growth rings to the analysis of stable isotopes, is a tool with potential for reconstructing and correlating environmental and climatic conditions. During the seasons of the year in which rainy and dry periods occur, the stomata found in tree leaves regulate gas exchange, allowing the entry of carbon dioxide (CO₂) necessary for photosynthesis, a process that can be limited in dry conditions due to the partial closure of stomata to prevent excessive water loss. During this process, the plant incorporates more ¹³C (heavy) in dry periods and more ¹²C in rainy periods. Thus, the δC values in wood reflect the environmental and physiological conditions existing at the time of growth ring formation. For tree species from seasonal tropical regions, this approach allows the investigation of physiological responses to hydrological and thermal variations over time. Given the scenario of climate change, understanding how these trees respond to water stress is important for the conservation and management of these ecosystems. Therefore, this study aims to develop a delta C (δC) chronology from annual growth ring series of *Cedrela fissilis* Vell., from the northern region of Minas Gerais state, near the Cavernas do Peruaçú National Park, to investigate the relationships between isotopic variations and climatic variables, as well as the physiological strategies of the species in a seasonally dry tropical forest environment. αcellulose was extracted from each growth ring of six previously dated trees, and subsequently isotopic analysis was performed using isotope ratio mass spectrometry (IRMS) coupled to an elemental analyzer (EA-IRMS). In parallel, historical climatic data from the region were obtained and compiled: precipitation, air temperature, Palmer drought index, and vapor pressure deficit. The data were subjected to δC-Climate Correlation and Principal Component Analysis (PCA) to investigate patterns among isotopic, physiological, and climatic variables. As a result, an intra-annual pattern of ¹³C was identified, although the individual Δ¹³C series showed low synchronism in their absolute values, a high interannual coherence was observed after the application of the first difference, indicating synchronized responses to year-on-year variations in precipitation, showing that water availability acts as the main driving factor of the isotopic composition of the wood. The results also indicate that the carbon ass variations in precipitation, showing that water availability acts as the main driving factor of the isotopic composition of the wood. The results also indicate that the carbon assimilated in the year prior to the current growth, strongly conditioned by rainfall, constitutes the main source for wood formation.
dissertação
Tolerância de gergelim (Sesamum indicum), carinata (Brassica carinata) e mostarda-indiana (Brassica juncea) a herbicidas aplicados em pré e pós-emergência
(Universidade Federal de Lavras, 2026-08-28) Ferreira, Ana Luiza Pereira; Pimentel, Guilherme Vieira; Melo, Christiane Augusta Diniz; Zandoná, Renan Ricardo; Silva, Laryssa Barbosa Xavier da
The diversification of feedstocks for food, industrial, and biofuel purposes has increased interest in oilseed crops such as carinata, Indian mustard, and sesame, for which information on herbicide tolerance remains scarce. Therefore, this study aimed to evaluate the tolerance of these three species to herbicides applied pre- and post-emergence, as well as the influence of soil conditions and herbicide rates on crop response. The dissertation comprised three articles, one for each species. The experiments were conducted under greenhouse conditions, with four replications. In the pre-emergence experiments, a randomized complete block design (RCBD) was used in a 2 × 5 factorial arrangement (two soil conditions × five herbicide rates), with clomazone, quinclorac, and fluroxypyr-methyl evaluated individually under two soil conditions. In post-emergence, a completely randomized design (CRD) with five herbicide rates was used to individually evaluate dicamba, quinclorac, halauxifen-methyl, florpyrauxifen-benzyl, and fluroxypyr-methyl. Tolerance was assessed based on visual crop injury, plant height, shoot dry mass, effective doses required to reduce the evaluated variables by 10% and 20%, and the Mean Tolerance Index (MTI). The experiments were repeated in two experimental periods. In carinata, quinclorac showed response associated with the highest effective doses estimated to cause a 10% reduction in crop response, with 43.00 g a.i. ha⁻¹ in pre-emergence, regardless of soil condition, and 59.83 g a.i. ha⁻¹ in post-emergence. In Indian mustard, quinclorac had an ED₁₀ of 32.96 g a.i. ha⁻¹ in pre-emergence, regardless of soil condition, whereas in post-emergence, no sufficient growth reduction was observed to estimate the ED₁₀ by the MTI for halauxifen-methyl. In sesame, fluroxypyr-methyl had an ED₁₀ of 18.79 g a.e. ha⁻¹ in pre-emergence and 22.70 g a.e. ha⁻¹ in post-emergence. The response to fluroxypyr-methyl differed among species and between application methods, whereas quinclorac showed distinct responses between sesame and the brassica species evaluated. Overall, the results demonstrate that tolerance of these oilseed crops depends on the active ingredient, herbicide rate, and application method. The tolerance of the same species to the same herbicide may vary according to the application method, whether pre- or post-emergence. A shared mechanism of action among herbicides is not sufficient to predict crop tolerance. These results provide a basis for prioritizing active ingredients for field validation and for developing safer chemical weed management strategies for these crops.
tese
Desenvolvimento e caracterização de micropartículas lipídicas sólidas obtidas po spray chilling contendo compostos bioativos naturais
(Universidade Federal de Lavras, 2026-04-29) Silva, Carlos Ramon de Paula; Borges, Soraia Vilela; Campelo, Pedro Henrique; Figueiredo, Jayne de Abreu; Botrel, Diego Alvarenga; Queiroz, Fabiana; Correa, Jefferson Luiz Gomes; Campelo, Pedro Henrique
This work presents the development and characterization of solid lipid microparticles (SLMs) produced by spray chilling and containing natural bioactive compounds, with a focus on the protection and controlled release of curcumin and carotenoids. The study is structured into three main components: the first article addresses the production of SLMs with a lipophilic extract of Curcuma longa, using murumuru butter and stearic acid as wall materials, with emphasis on storage stability and performance under in vitro digestion; the second article focuses on the encapsulation of carotenoids extracted from annatto (Bixa orellana), evaluating different extraction methods and lipid-based materials in relation to the physicochemical properties of the particles; and the third component corresponds to a patent application for a sustainable and efficient technique for the lipophilic extraction of bioactive compounds directly into lipid matrices. The resulting microparticles exhibited spherical morphology, thermal and oxidative stability, high retention of bioactive compounds, and targeted release in simulated gastrointestinal conditions. The proposed encapsulation approach by solvent-free spray chilling proves suitable for heat-sensitive compounds and promotes the valorization of Amazonian resources for functional applications in the food, cosmetic, and pharmaceutical sectors. Furthermore, the findings contribute to strengthening the bioeconomy and adding value to native Amazonian species, aligning with sustainability guidelines and technological innovation. The multidisciplinary approach, encompassing food science, process engineering, and sustainability, endows this thesis with academic, industrial, and societal relevance, fostering the utilization of natural resources through feasible and environmentally responsible technological solutions.
Artigo
Wavelets in the analysis of seed image similarity: an approach using the Hurst directional exponent
(2022-10-27) Cassiano, Fernando Ribeiro; Sáfadi, Thelma; Guimarães, Paulo Henrique Sales
Modernization is present in all fields of knowledge. The wavelet transform and the Hurst exponent are tools that have fundamental importance in many of these advances. In the present study, the wavelet decomposition technique was combined with the Hurst exponent calculation to analyze X-ray images of seeds and thus classify them as full, slightly damaged or damaged. To calculate the Hurst exponent the mean and median were used as measurements of position. A support vector machine was used to validate the proposed method. For the full, damaged and slightly damaged seed groups, the average accuracy of the method, using the mean as measure position, was 74.5%, and using the median was 57.05%. For the full and damaged seed groups, the average accuracy using the mean was 99.76%, and using the median was 80.93%. For the slightly damaged and damaged seed groups, the average accuracy, using the mean as measure of position, was 99.26%, and the median was 76.22%. When analyzing seeds with slight damage, we observed a decrease in accuracy because the classification of the X-rays was subjective. Therefore, for the image database used in this study, the proposed methodology is efficient for automatic classification.