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Abordagem de martingais para análise assintótica do passeio aleatório do elefante
(Universidade Federal de São Carlos, 2018-08-20) Miranda Neto, Milton; Gava, Renato Jacob; https://lattes.cnpq.br/0494315910583969; https://lattes.cnpq.br/2915296953908754
In this work we study the elephant random walk introduced in (SCHUTZ; TRIMPER, 2004), a discrete time, non-Markovian stochastic process with unlimited range memory that presents phase transition. Our objective is to proof the almost sure convergence for the subcritical and critical regimes of the model. We also present a demonstration of the Central Limit Theorem for both regimes. For the supercritical regime we proof the convergence of the elephant random walk to a non-normal random variable based on the articles (BAUR; BERTOIN, 2016), (BERCU, 2018) and (COLETTI; GAVA; SCHUTZ, 2017b).
Fisiologia de Chlorella sorokiniana e Ankistrodesmus densus: efeitos e dinâmica de nanopartículas de cobre
(Universidade Federal de São Carlos, 2018-08-20) Barreto, Daniela Mariano; Tonietto, Alessandra Emanuele; https://lattes.cnpq.br/3056194008699912; Lombardi, Ana Teresa; https://lattes.cnpq.br/6737850858443813; https://lattes.cnpq.br/0725648167756426
The phytoplankton community is composed of microalgae that support food chains in aquatic ecosystems. In these environments they are immersed in a complex matrix of organic and inorganic substances. In some situations, they are still subject to a range of anthropogenic wastes that end up entering aquatic environments, such as nanoparticles (NPs). Due to the unique characteristics of NPs, their use is intense, even if neither use nor disposal is regularized by competent governamental agencies. Toxicological studies on the effect of NPs on phytoplankton have controversial results. The toxicity of NPs is related to their reactivity, which depends on the size of the particles, formation of aggregates, availability of organic matter, among other factors. In this study, we first sought to understand the dynamics of NPs in algal cultures and followed investigating on the physiological effects of copper NPs (NPs-Cu) on two freshwater Chlorophyta (Chlorella sorokiniana and Ankistrodesmus densus) exposed to nominal NPs-Cu concentrations estimated for the environment (0.57 to 12.70 μg L-1) and above these (up to 635.0 μg L-1). We analyzed parameters related to growth, photosynthesis and intracellular biomolecules under controlled laboratory conditions at 72 h cultures. The results showed that the population growth rate was affected in both microalgae species. The intensity of the photosynthetic processes varied according to the microalgae, with C. sorokiniana being more resistant than A. densus that presented reductions in photosystem II quantum yield, electron transport rates and consequentely in the estimated gross primary productivity. The biochemical composition (proteins, carbohydrates and lipids) was affected in the presence of NPs-Cu in both microalgae, but at environmentally relevant concentrations of NPs-Cu only carbohydrates were affected. Protein synthesis was stimulated at the higher end of the NPs-Cu concentration range, suggesting the production of antioxidant proteins associated with cell detoxification. This study is a contribution to the knowledge of the toxicology of NPs to freshwater microalgae and their possible consequence in natural environment.
Otimização superestrutural de biorrefinaria de cana-de-açúcar com hidrólise e gaseificação da biomassa vegetal e biodigestão da vinhaça e do licor de pentoses
(Universidade Federal de São Carlos, 2018-08-20) Fonseca, Gabriel de Castro; Costa, Caliane Bastos Borba; https://lattes.cnpq.br/1602653870311562; Cruz, Antonio José Gonçalves da; https://lattes.cnpq.br/1812806190521028; https://lattes.cnpq.br/4378950347916839
The production of ethanol in sugarcane biorefineries generates large amounts of by-products such as straw, bagasse and vinasse. The objective of this work was to develop and implement a tool for the analysis of investments within the framework of a sugarcane ethanol bio-refinery (E1G) designed to take advantage of all these by-products in the production of second generation ethanol (E2G) and electricity. The combustion of bagasse in low pressure boilers for energy self-sufficiency of the process is a widely used technology. Not all distilleries, however, adopt the technology to produce surplus electricity. Two alternatives for the production of these surpluses were examined: the combustion of straw and bagasse in high pressure boilers (Rankine cycle) and biomass integrated gasification combined cycle (BIGCC). The impact of biogas production by anaerobic digestion of vinasse on the techno-economical viability of the process was also investigated, since the production of second generation ethanol leads to vinasse throughputs even larger than those observed in traditional distilleries. An autonomous distillery with capacity to process 3.84 million tons of cane per harvest and recovery of 50 % of straw from the field was considered. The economic analysis was based on factored-cost estimates and on superstructural optimization in order to define the optimal fraction of hydrolyzed bagasse and the best process for energy production. The uncertainty regarding the economic analysis was estimated by the Monte Carlo method. Different case studies were evaluated assuming changes in product prices, reduction in investment costs due to technological learning effects and expectations for the long-term scenario. In most scenarios the optimal operation involved the generation of electricity by combustion of biomass in high pressure turbines and in all scenarios, the optimum involved the hydrolysis of all bagasse and the production of biogas. Nonetheless, under the conditions evaluated in this work, none of the scenarios evaluated were deemed economically feasible, suggesting that these technologies are not yet sufficiently mature for commercial use without support from the public sector.
Impactos econômicos globais da redução das emissões de gases de efeito estufa
(Universidade Federal de São Carlos, 2018-08-20) Silvestrini, Murilo Mazzotti; Gomes, Alexandre Lopes; https://lattes.cnpq.br/5002157193962189; https://lattes.cnpq.br/8183879774699219
The purpose of this work is to simulate reductions in global greenhouse gas emissions (GHG) to analyze the behavior of emissions and gross production value (GVP) of 40 countries considering the global emission mitigation target, identifying those that present greater economic impact. The methodology of this work is based on the use of Linear Programming and Input-Output in the Multi Regional matrix with GHG emissions, and the data used are from the WIOD tables which represents 40 countries composed by 35 sectors for the year 2009. Three different scenarios were modeled: the pessimistic scenario, the moderate scenario and the optimistic scenario, with reduction of 10%, 30% and 50% of the global GHG emissions, respectively. The results showed the greatest emission reductions in China, India, Russia and Brazil, which also showed the greatest decrease in VBP. The United States and Japan, despite of presenting a high percentage of emission reductions, especially in the optimistic scenario, had a lower economic impact due to their economic structure. European countries, such as Germany, the United Kingdom and France, showed little reduction in emissions and VBP. Furthermore, the scenarios modified the overall composition of emissions and VBP, with the share of GHG emissions increasing in European countries, in addition to the increase of their participation in global VBP. The conclusion is that the reduction of emissions in the face of a global GHG mitigation goal is greater in the most emission-intensive countries, causing the greatest economic impact, mainly due to the production structure of the economic sectors based on higher emission technologies.
Desafios contemporâneos da Ciência da Informação: influenciadores digitais como objetos de investigação
(Universidade Federal de São Carlos, 2018-08-20) Dantas, Melina Simardel; Gracioso, Luciana de Souza; https://lattes.cnpq.br/4898201916360294; https://lattes.cnpq.br/7343134610824006
Constantly, new informational practices have been strengthened by virtual and collaborative information and communication technologies in contemporary times. In this context, the (informational and communicational) practices used by digital influencers consist of a new information action, which, according to this work, have been poorly explored in the scientific perspective of Information Science (IS). In this scenario, the general objective of this research was to bring the IS closer to the new actions of production and consumption of information on the web promoted by digital influencers, analyzing how studies of these new informational practices and informational individual would fit the scope of Information Science. Based on bibliographical research and literature review, studies were carried out both to contextualize and characterize IS, information as its object of study and contemporary users of information, as well as to understand the current informational individuals and current information and communication practices, to produce relations between Information Science and digital influencers. It was noticed that IS, in its evolution as a scientific area, has become a science capable of investigating a wide range of contents, not being restricted to the technical and theoretical aspects related to information, being also in the field research related to the aspects applied and social information uses and users. The objective was to understand, describe and contextualize the digital influence and digital influencers in IS, suggesting approximations of the topic in the range of the Working Groups (WGs) of the National Meeting of Research in Information Science (ENANCIB), indicating possible tendencies for studies about digital influencers in Information Science.