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Modelos de sobrevivência induzidos por fragilidade discreta com fração de cura e riscos proporcionais
(Universidade Federal de São Carlos, 2022-10-21) Espírito Santo, Ana Paula Jorge do; Cancho, Vicente Garibay; https://lattes.cnpq.br/3503233632044163; https://lattes.cnpq.br/7428767920770482
This work presents two new survival models induced by discrete frailty with unobserved heterogeneity and proportional hazards structure, for lifetime data. The first model consider the discrete frailty variable with Katz distribution and the second with Generalized Poisson distribution, which have overdispersion, equidispersion and underdispersion properties. The new models encompasses as particular case the promotion cure rate model. The proposed model with katz discrete frailty also encompasses the mixture cure rate model and cure rate model with dispersion. Inference aspects for proposed models as discussed, in a classical approach for Katz distribution, for which the maximum likelihood tools were used and regression models were presented to evaluate the effects of covariates in the cured fraction. Furthermore, an expectation maximization algorithm for determining the maximum likelihood estimates of the parameters of the model was presented. For Generalized Poisson model, a baysean aprouch was also used, through Markov chain Monte Carlo simulation method, especifically Metropolis–Hastings algorithm. Finally, the modeling was fully illustrated on cervical cancer data sets.
Desenvolvimento de procedimentos para a determinação de cobre e zinco em fertilizantes minerais misto por espectrometria de emissão óptica com plasma induzido por micro-ondas (MIP OES)
(Universidade Federal de São Carlos, 2022-10-21) Fidelis, Suzane Cristina; Nogueira, Ana Rita de Araújo; https://lattes.cnpq.br/7034773971317045; https://lattes.cnpq.br/1343707476494928
DEVELOPMENT OF PROCEDURES FOR COPPER AND ZINC DETERMINATION IN MIXED MINERAL FERTILIZERS BY MICROWAVE-INDUCED PLASMA OPTICAL EMISSION SPECTROMETRY (MIP OES). In the pulp industry, eucalyptus, introduced in Brazil in 1904, is the main raw material, according to the Brazilian Association of Silviculture. For these plants' good development, fertilizers must be used to meet their nutritional needs. In this approach, the determination of nutrients both in plants and in fertilizers is a demand of industrial quality control laboratories. Mixed mineral fertilizers, specifically the micronutrients copper and zinc, were the object of the present study. In partnership with the raw material supplier, aspects related to sampling were evaluated, and compaction during transport was investigated. Next has studied the sample preparation, with digestions involving open vials and assisted by microwave radiation. The determination of the analytes (copper and zinc) was performed by microwave-induced plasma optical emission spectrometry (MIP OES). The equipment and materials necessary for the execution of this project were made available in the laboratories of Bracell, unit in Lençóis Paulista, in the São Paulo State. The raw material responsible for being the source of copper and zinc (10% of each nutrient) was provided by the supplier. Different extractor solutions such as aqua regia, sulfuric acid, and citric acid did not show greater extractions effectiveness than hydrochloric acid, the method recommended by the manual of analytical methods of the Braziliam Ministry of Agriculture, Livestock and Food Supply (MAPA). The wet digestion procedure in an open system on a hot plate presented statistically similar mean values (paired t-test) compared to the digestion performed in a closed system in a microwave digester for Cu. Otherwise, for Zn, the digestion assisted by microwave radiation was less effective, which suggested problems related to the heater program. The matrix after grinding (20 mesh) and the intermediate portion (retained in a sieve) were analyzed. Addition and recovery tests showed high recovery levels in part had on the sieve in all extractor studied solutions. The results suggest a possible matrix effect in MIP OES determinations, indicating the need to evaluate new alternatives for calibration or the use of an internal standard.