https://tedebc.ufma.br/jspui/handle/tede/5995 Credenciado pela CAPES como Mestrado Acadêmico, na área de Geociências, o PPGC&TAmb teve início com a atualização do seu Regimento Interno em outubro de 2022, conforme decisão do Conselho de Ensino, Pesquisa, Extensão e Inovação (Consepe). Este marco reforça o compromisso da UFMA em promover a excelência acadêmica e impulsionar o avanço científico e tecnológico na região. Esta Coleção contém os trabalhos do Mestrado Acadêmico. 2026-07-21T17:10:04Z https://tedebc.ufma.br/jspui/handle/tede/7092 Título: Sobreposição entre a área de vida do boto-cinza (Sotalia guianensis) e os estressores antrópicos na baía de Sepetiba, Rio de Janeiro, Brasil. Autor: KINGUARI, Distinto Marcos Alberto Primeiro orientador: RINCON FILHO, Getulio Abstract: In the current Anthropocene context, the growing pressure of multiple anthropogenic stressors is increasingly impacting coastal and marine ecosystems. The Guiana dolphin (Sotalia guianensis), a key species and indicator of environmental health, is particularly affected by these pressures in Sepetiba bay, on the southern coast of Rio de Janeiro state, Brazil. The study aimed to determine the Guiana dolphin's home range and its relationship with anthropogenic stressors in the bay. Home range is an important ecological parameter because it represents the daily activities of individuals and was calculated using the Minimum Convex Polygon (MCP) method, and overlapping with areas of human activity was estimated using GIS. Seventy-seven field trips were conducted between 2006 and 2007, totaling 261.37 hours of sampling effort. During this period, 59 individuals were photo-identified, of which 48 were recaptured over more than three days of sampling effort. Of these, 9 had information on the geographic positions of each recapture. The results revealed that home ranges ranged from 19.14 km² to 73.97 km², with an average of 42.60 ± 16.24 km², and overlap of 7.85% to 20.60% with anthropogenic stressors, especially navigation channels and anchoring areas. This indicates that dolphins use strategic feeding areas, even in high-traffic areas, exposing themselves to risks such as collisions, noise pollution, and chemical contamination. It was concluded that, although the Amazon River Dolphin Environmental Protection Area (APA) has potential for conservation, its effectiveness is limited by the intensification of human activities. The implementation of mitigating measures, such as speed reduction zones and a review of the management plan, is recommended to balance economic development and species conservation. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação 2025-09-30T00:00:00Z https://tedebc.ufma.br/jspui/handle/tede/7068 Título: DESENVOLVIMENTO DE BIOINSUMOS PARA O CONTROLE DE INSETOS EM CULTIVOS DE ARROZ (O. sativa L.) Autor: FREITAS, Debora Serra Primeiro orientador: OLIVEIRA, Regina Maria Mendes de Abstract: The development of bioinputs represents a strategic and sustainable alternative for controlling insect pests in agricultural crops. Thus, the objective of this work was to develop natural formulations, including extracts of Azadirachta indica (neem), free lausone (from Lawsonia inermis) and complexed with magnesium ions, for the control of insect pests of stored grains. The methodology was structured in stages: diagnosis of the main rice pests; preparation of natural and treated plant extracts; synthesis and characterization of a magnesium-lausone coordination compound (Mg-bisla); preliminary toxicity testing on Artemia salina; and bioassays of insecticidal and repellent activity against Tribolium castaneum and Sitophilus zeamais. Analytical and spectroscopic characterization data indicate the formation of the Mg-bisla compound, which exhibits superior thermal stability to free lausone. Biological assays revealed that, although no significant mortality due to ingestion was observed in T. castaneum, fresh neem leaf powder showed a repellent effect, while treated neem and Mg-bisla exhibited attractive behavior. Free lausone showed significant repellency against T. castaneum. In contact tests, both lausone and Mg-bisla showed low efficacy in the mortality of S. zeamais (10%), being lower than commercial neem oil (30%). The reduced toxicity of Mg-bisla in A. salina suggests potential for safe application. In conclusion, the results demonstrate the selective potential of bioinputs in grain protection, reinforcing the importance of coordination chemistry as a tool for modulating biological properties. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação 2025-09-24T00:00:00Z https://tedebc.ufma.br/jspui/handle/tede/7058 Título: ESTUDO DO POTENCIAL ANTIOXIDANTE DO EXTRATO ETANÓLICO DA AMBURANA CEARENSIS COMO FATOR DETERMINANTE NA ESTABILIDADE OXIDATIVA DO BIODIESEL DE SOJA Autor: COSTA, Bárbara Beatriz Caxilé Primeiro orientador: PASSOS, Ionara Nayana Gomes Abstract: This master’s thesis aims to investigate the oxidative stability of biodiesel through the use of an ethanolic extract obtained from the exudate of Amburana cearensis as a natural antioxidant additive. The incorporation of antioxidants is a widely used strategy to mitigate the oxidative degradation of biodiesel; however, synthetic antioxidants are often associated with high cost, potential toxicity, and low biodegradability, making the discovery of new chemical substances an area of significant scientific advancement. Experimental results for the ethanol extract of Amburana cearensis demonstrated antioxidant efficacy as determined by the ABTS •⁺ radical scavenging assay, which showed high antioxidant activity even with mass loss over time. Thermogravimetric and differential thermal analysis (TG/DTA) revealed its thermal stability at high temperatures, with degradation beginning at 281°C. Chemical characterization by HPLC and DI-ESI-IT-MSn identified the compounds responsible for the antioxidant activity; the predominant metabolite was associated with coumarins, flavonoids, and phenolic acids. Fragments of five compounds were identified as butein, calicosin, cirsimaritin, 3,5,3-trihydroxy-7,4-dimethoxyflavone, and nevadensiv. The extract’s efficacy as an antioxidant in biodiesel was evaluated using the Rancimat method (EN 14112). The treated sample exhibited an induction time of 11.03 h with 3000 ppm of the ethanolic extract, coming very close to the limits established by the National Agency of Petroleum, Natural Gas, and Biofuels (ANP). Overall, the phytochemicals present in the exudate of Amburana cearensis demonstrate significant scientific, environmental, and socioeconomic potential, supporting its use as a green and regional alternative to synthetic antioxidants. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação 2026-02-27T00:00:00Z https://tedebc.ufma.br/jspui/handle/tede/7042 Título: Atividade inseticida, fagoinibidora e repelente de extratos e frações de Solanum paniculatum sobre Sitophilus zeamais (coleoptera: curculionidae) Autor: MATA, Raylane Rocha da Primeiro orientador: PASSOS, Ionara Nayana Gomes Abstract: Post-harvest losses caused by insect pests represent one of the main factors responsible for the reduction in the quality and quantity of stored grains, with the maize weevil, Sitophilus zeamais, standing out as one of the species of greatest economic importance. In this context, the present study aimed to evaluate the bioinsecticidal potential of extracts and fractions obtained from the leaves of Solanum paniculatum in the control of S. zeamais. The plant extracts were obtained through an extraction process and subsequently fractionated using solvents of different polarities, being evaluated through laboratory bioassays of mortality and insecticidal activity. Additionally, qualitative phytochemical and chromatographic analyses were performed to identify the main secondary metabolites present. The results demonstrated high bioinsecticidal activity of the tested extracts and fractions, with emphasis on the crude extract and the acetate organic fraction, which showed high insect mortality rates. Chemical analyses indicated the presence of phenolic compounds, flavonoids, and lipophilic substances, metabolites frequently associated with insecticidal activity. Therefore, it is concluded that Solanum paniculatum presents promising potential as a source of natural compounds for the development of bioinsecticides applicable to the sustainable management of stored-grain pests. Instituição: Universidade Federal do Maranhão Tipo do documento: Dissertação; Documento sob sigilo. Prazo provável para disponibilização total: 3 anos. Motivo do sigilo: publicação de artigo. 2026-02-26T00:00:00Z