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Avaliação por RMN de alta resolução da presença de cereais não maltados na produção de cervejas
(Universidade Federal de São Carlos, 2020-07-16) Esteves, Rafael Rodrigues; Ferreira, Antonio Gilberto; https://lattes.cnpq.br/3676462220401452; https://lattes.cnpq.br/5523423303982070; https://orcid.org/0000-0001-8221-1394
Statistics show that beer is the most widely consumed alcoholic beverage in the world and it is made up of water, barley malt, hops and yeast as main ingredients. The use of non-malted cereals in beer production is common to reduce the production cost, however the amount used is not declared in the labels. Typically in industrial production, barley malt substitutes are the cheaper sub products from corn (Zea mays) and rice (Oryza sativa). To know about the capability of NMR on detection of different non-malted cereals in beer production, nine beers were produced with different percentages of barley malt, corn grains and rice flakes. The samples were collected during all important stages of production and fermentation. The method was developed with easily preparation of samples, just being a dilution of the sample in deuterated water to avoid errors associated with this step. The ¹H RMN spectra were acquired in a 9.4 Tesla (400 MHz) Bruker® equipment, model AVANCE III, using a 5 mm BBI probe, with the pulse sequence NOESYGPPR1D, being acquired and processed in the Topspin 3.5 pl.7 software. For the chemometric analysis (PCA) was used the AMIX® software version of the 3.9.3 package. Using PCA in the ¹H NMR spectra, it was possible to discriminate the groups of beers produced exclusively with barley malt from beers produced with 30% and 45% non-malted cereals. This analysis showed that the main compounds and metabolites responsible for this discrimination were succinic acid, α(1,4)-glucose, pyruvic acid, and alanine. Finally, it is possible to conclude that the use of ¹H NMR spectroscopy combined with chemometric analyzes were able to discriminate with high precision the presence of non-malted cereals in beer production. These results demonstrate the separation of groups of beers produced with different amounts of adjuncts. Although the results are still initial, they demonstrate the technique's potential for continuing this study and other work that uses NMR applied to food and beverages.
Cure rate models: alternatives methods to estimate the cure rate
(Universidade Federal de São Carlos, 2020-07-16) Rodrigues, Juliana Scudilio; Tomazella, Vera Lucia Damasceno; https://lattes.cnpq.br/8870556978317000; https://lattes.cnpq.br/5189010086005005
Cure rate models in survival data studies has formed an important field in the area and has attracted the attention of researchers. In the search for new models of cure rate, the objective of this work is to propose alternative methods to model the cure rate. For this two methods are presented. The first use the methodology of the defective models and the last method use the concept the distributions family. Then, in the first method propose the defective models induced by a frailty term. Defective models have the advantage of modeling the proportion of cured without adding any extra parameters in the model, in contrast to the most models from the literature. Models with a frailty term incorporate an unobserved heterogeneity among individuals and this incorporation brings advantages for the estimated model, because it incorporates the influence of unobserved covariates in a proportional hazard model. It is showed that the new defective distributions are induced when using the gamma frailty term. The last method proposed in this work, is to use distribution families to calculate the cure rate. For this, a parameter $"p"$ is included in the Beta-G family in order to create a new family of cure rate models, the new family can be more flexible for modeling cure rate than the standard mixture models.
Home field advantage effects on decomposition of leaf litter in tropical riparian forests: effects of restoration age, litter quality and soil nutrients
(Universidade Federal de São Carlos, 2020-07-16) Oliva, Rebeca Leme; Veen, Ciska; Tanaka, Marcel Okamoto; https://lattes.cnpq.br/2768658925977757; https://lattes.cnpq.br/5883865030300571
Decomposition of organic matter is influenced by several biotic and abiotic factors. Litter quality, soil nutrient concentration and plant-soil interactions are major factors influencing this ecosystem process in forests at local scales. The home field advantage effect (HFA) has been proven to accelerate decomposition rates for litter at its own home when compared to away sites, and is directly related to the previously mentioned factors. HFA effects can occur in natural forests, but it is still unknown if it can be detected in riparian areas under restoration. Here, we tested if litter quality, soil nutrient concentrations and restoration stage (age) influenced HFA. We carried out three-way reciprocal litter transplant experiments to test the following hypotheses: (1) areas under restoration of the same age, but with differences in soil nutrient concentration and litter quality, will show HFA in areas with low litter quality and soil nutrient concentration; (2) areas under restoration with different ages, but with similar content of soil nutrients and litter quality, will present HFA in older areas, given that decomposers and plants had more time to develop close-knit positive relationships; (3) riparian forest intact remnant areas (i.e., areas not undergoing restoration) that differ in soil nutrient concentrations and litter quality would present HFA in areas with low litter quality and soil nutrient concentrations. Our results indicated no effects of HFA in any hypotheses tested, although we found some support for hypothesis 1 as there was an ability effect in one area and a trend for a negative HFA effect in another. Leaf litter decomposed very fast across all areas possibly due to heavy rainfall in the end of the experiment, so that labile litter was likely totally decomposed, which could obscure HFA effects. We also analyzed the results of the three independent experiments simultaneously to test the additional hypotheses: (4) soil nutrients and litter quality would affect HFA and (5) higher dissimilarities in soil nutrient concentrations and litter quality between home and away sites would result in stronger HFA effects. We found a relationship between HFA and leaf litter quality, and also a relationship between HFA and dissimilarity in soil quality between home and away sites. Also, the most dissimilar areas were the remnant areas. In natural ecosystems, such as forest remnants, plants may have more time to develop relationships with the soil community, in comparison to the riparian forest fragments under restoration studied. This high dissimilarity among remnant areas could also be due to the development of other complex heterogenous plant-soil relationships, established throughout time. Therefore, our studies suggest that although these riparian forest areas under restoration can cover large areas, the time after restoration may not have been enough to recover microbial communities and more specialized ecosystem functions.