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Elaboração de modelo conceitual para monitoramento de riscos à contaminação da água em comunidades rurais
(Universidade Federal de São Carlos, 2020-03-13) Corrêa, Rony Felipe Marcelino; Ventura, Katia Sakihama; https://lattes.cnpq.br/0765182109837821; https://lattes.cnpq.br/3531381750355708
Some practices and activities adopted in rural communities can impair water quality consumed by owners. The Water Safety Plan (WSP) is a tool proposed by the World Health Organization (WHO) to prevent drinking water contamination for human consumption. The objective of this research was to develop a conceptual model for monitoring risks associated with water contamination in rural communities. The methodology consisted of the following phases: i) characterization of rural sanitation; ii) structuring the risk prioritization matrix; iii) structuring an evaluation and monitoring model; iv) elaboration of software; v) validation of the database; vi) software calibration and validation. As a result, a conceptual model for risk monitoring was conceived as an instrument to assist in the application of WSP in rural communities. The calibration and validation of the software was carried out in rural properties in the interior of São Paulo. The results of the calibration and validation indicate that the hazardous events with the greatest risk of contamination in the properties visited were the presence of feces and the presence of agricultural livestock near the water catchment. Other less impactful events were highlighted, such as irregular disposal of domestic waste and effluents, precarious conditions in water storage tanks and transportation of water to homes. These circumstances were pointed out in the literature and the software made it possible to identify and measure the risk. The software covered the preliminary and evaluation stages of the WSP system, and was submitted to validation and calibration. The monitoring of the WSP depends on the application of prevention mechanisms, such as the software developed, in the rural area.
Optimization models and solution methods for inventory routing problems
(Universidade Federal de São Carlos, 2020-03-13) Álvarez Díaz, Aldair Alberto; Morabito Neto, Reinaldo; https://lattes.cnpq.br/4194801952934254; Munari Junior, Pedro Augusto; https://lattes.cnpq.br/1328868140869976; https://lattes.cnpq.br/9595205651065613
Inventory management and distribution planning are essential activities for an efficient performance in the supply chain, especially for companies operating under the vendor-managed inventory business model. In this model, suppliers are allowed to manage the inventory levels and purchasing orders of their customers with the aim of reducing logistics and improving the supply chain performance. When inventory management and distribution planning are addressed in an integrated way in the vendor-managed inventory context, a challenging optimization problem arises, the inventory routing problem (IRP). In the IRP, a supplier is responsible for simultaneously determining the replenishment plan for its customers throughout a planning horizon as well as the vehicle routing and scheduling plan in each period such that a given performance measure is optimized. The integrated optimization of inventory management and distribution planning activities can provide significant competitive advantages for companies. However, despite its practical appeal and benefits, the IRP has received increasing attention only in the last years. Consequently, there is still a considerable lack of research regarding optimization models and specific solution methods for relevant practical variants of this problem. Thus, the objective of this thesis is to develop comprehensive mathematical models and effective solution methods for several IRPs. Relevant variants are considered to make the addressed problems as realistic as possible. Firstly, we describe the basic variant of the IRP and present a mathematical formulation for this problem. We then present two metaheuristic algorithms based on iterated local search and simulated annealing to solve this variant. Two different objective functions are considered. The results of extensive computational experiments using problem instances from the literature show that the presented metaheuristic algorithms effectively handle both objective functions, providing high-quality solutions within relatively short running times. In addition, the metaheuristics were able to find new best solutions for some of the benchmark instances. Then we shift to a practical variant of the IRP considering product perishability. This feature has a substantial relevance in the supply chain context given that in several industries, the raw materials, as well as intermediate and final products, are often perishable. Moreover, perishability may appear in more than one activity throughout the supply chain. We study a variant in which the product is assumed to have a fixed shelf-life with age-dependent revenues and inventory holding costs. We first introduce four different mathematical formulations and branch-and-cut algorithms to solve them. We also propose a hybrid heuristic based on the combination of an iterated local search metaheuristic and two mathematical programming components. The results of computational experiments show the different advantages of the introduced formulations and the effectiveness of our hybrid method when dealing with this variant as well as the basic variant of the problem. Finally, we focus on a stochastic variant of the IRP. Uncertainty plays a crucial role in supply chain management given that critical input data that are required for effective planning often are not known in advance. We address the basic variant of the IRP under the consideration that both the product supply and the customer demands are uncertain. We introduce a two-stage stochastic programming formulation and a heuristic solution method for this problem. From the results of extensive computational experiments, we show the response mechanisms of the optimal solutions under different uncertainty levels and cost configurations. We also show that the heuristic method effectively solves instances with a large number of scenarios. By investigating different practical constraints for the IRP and providing tailored effective solution methods for the studied variants, this thesis addresses problems arising in several logistics contexts and shows the adaptability of the basic variant of the IRP and how it can be used as a basis to study richer practical IRPs. It brings contributions for the supply chain optimization literature and for the development of tools for supporting decision-making in practice.
Avaliação funcional da interação entre os núcleos da rafe e o núcleo retrotrapezóide nas respostas ventilatórias à hipercapnia em ratos
(Universidade Federal de São Carlos, 2020-03-13) Leirão, Isabela de Paula; Colombari, Débora Simões de Almeida; https://lattes.cnpq.br/1684467594359403; Zoccal, Daniel Breseghello; https://lattes.cnpq.br/1958567557189244; https://lattes.cnpq.br/3141506091837442
During hypercapnia, chemosensory cells located in the brainstem are stimulated and send excitatory inputs to the respiratory network to promote an increase pulmonary ventilation. Among the candidates responsible for central chemoreception are the raphe serotonergic neurons, which widely send projections to distinct respiratory compartments. In spite of the anatomical evidence, there are few functional studies demonstrating how the raphe serotonergic neurons interact with the respiratory network, specially other chemosensitive sites. Herein, we explored the hypothesis that the ventilatory response to hypercapnia depends, at least in part, on the stimulation of the raphe serotonergic neurons that send projections to the retrotrapezoid nucleus (RTN) - an important respiratory region of the ventromedullary surface that contains CO2/pH sensitive cells. To reach this goal, the pulmonary ventilation was evaluated under baseline conditions and during the exposure to hypercapnia in unanesthetized juvenile Holtzman rats (60 - 90 g) that received bilateral microinjections of the toxin anti-SERT-SAP (0.1 mM) in the RTN to selectively lesion serotonergic neurons that send projections to this region. Fifteen days after microinjections of anti-SERT-SAP in the RTN (n = 8), baseline respiratory frequency (f) and tidal volume (VT) were not different from control animals that received vehicle microinjections (n = 9). On the other hand, the specific ablation of RTN-projecting serotonergic neurons markedly attenuated the response of increase in the f, but not in the VT, observed during the exposure to 7% CO2. The impaired tachypneic response to hypercapnia induced by anti-SERT-SAP microinjections in the RTN was associated with reduced number of serotonergic neurons in the raphe obscurus and magnus, but not in the raphe pallidus. Our data support the idea that, in the absence of anesthesia, the activation of part of medullary raphe serotonergic neurons that send projection to the RTN are necessary for the processing of ventilatory reflex responses during the exposure to high CO2.
O Estado mínimo de Robert Nozick: uma análise acerca dos limites da ação estatal
(Universidade Federal de São Carlos, 2020-03-13) Foderario, Vinicius Elias; Stival, Monica Loyola; https://lattes.cnpq.br/0624149613819754; https://lattes.cnpq.br/3219982170294571
The aim of this research is to analyze the limits of state action, based on the perspective of political liberalism. The theme is approached from the criticism made by Robert Nozick, in Anarchy, State and Utopia (AEU), the idea of a redistributive State defended by another liberal, John Rawls. Since the defense of freedom is the foundation of liberal theories, we are interested in understanding the space that individual freedom leaves so that the democratic state of law can act without violating the private freedom of the citizen. The general objective of the research obliges us to go through themes, such as: positive freedom, negative freedom, limits of state action, social justice, free market, state intervention, social state, state restricted to security functions, among others. However, the research is limited to analyzing the topic from a moral perspective, that is, the purpose is to understand whether, contrary to what Nozick argues, it would be possible to think of a liberal state that develops social functions, without this, necessarily, morally violates the individual's private freedom. During the analysis, arguments are presented in defense of individual freedom from a conception of a redistributive State, as well as arguments in favor of a minimal state structure, restricted only to protection functions. In general, the research presents the debate carried out between the egalitarian liberalism of John Rawls, present in A Theory of Justice (TJ), and the free process liberalism of Robert Nozick.
O Inventário de envolvimento paterno: estrutura teórica e ampliação de indicadores de validade e de precisão
(Universidade Federal de São Carlos, 2020-03-13) Santis, Ligia de; Peixoto, Evandro Morais; https://lattes.cnpq.br/1872961522740682; Barham, Elizabeth Joan; https://lattes.cnpq.br/9868595523538592; https://lattes.cnpq.br/3392206001969455
Father involvement is influenced by psychosocial factors in the lives of parents and children and is associated with the healthy development of children and the well-being of parents. A model of the interpersonal processes related to this construct, and a psychometrically sound instrument to measure father involvement would contribute to improving the quality of professional work in this area, in Brazil. The Inventory of Father Involvement (IFI) has been adapted for use in Brazil (the IFI-BR), and although initial evidence of its validity has already been demonstrated, further information is needed to support evidence-based practice. Thus, the objectives of the present study were to: (a) continue to investigate the validity of the IFI-BR, examining additional evidence of the internal validity of the instrument, and its relation with other constructs, (b) compare results for fathers who responded to the instrument in-person, or on-line, and (c) evaluate a processes model of father involvement. Participants included 1,085 fathers with children in early childhood education and primary school settings. They completed the IFI-BR, a sociodemographic questionnaire, the Perceived Stress Scale, and two of the following measures: a second measure of father involvement (the Paternal Engagement Questionnaire or the Parenting Practices Inventory), the Marlowe-Crowne Social Desirability Scale, the Social Skills Inventory - Del Prette, and the Preschool and Kindergarten Behavior Scale. In Study 1, estimators of the precision and evidence of the internal validity (using factor analysis) of the IFI-BR were analyzed, for two samples: (a) fathers with children in early childhood education settings and (b) fathers with children in grades one to five. Based on these results, suggestions were made for changing some of the items. In Study 2, evidence for the internal validity of the modified version of the IFI-BR was examined, confirming the nine-factor structure of the American version of the IFI with the Brazilian sample of fathers with children in preschool through to grade five. The precision of the nine factors varied from 0,611 ≤ ω ≥ 0,779. In Study 3, evidence was found with respect to: (a) convergent validity, and (b) associations with related constructs, for the IFI-BR. In Study 4, initial evidence of validity based on the internal structure of the on-line version of the measure was observed, confirming the American structure of the IFI, with adequate estimators of precision (0,608 ≤ ω ≥ 0,838). However, some differences were found in the level of father involvement and in the sociodemographic profile of each group of fathers. Finally, in Study 5, the interpersonal process model was evaluated, confirming that some demographic variables and the fathers’ social skills predict the quality of father involvement. Fathers’ stress seems to act both as a predictor and as an outcome of father involvement. These results indicate the potential of the IFI-BR in assessing the quality of father involvement with Brazilian fathers of children from early childhood education through to grade five, for both the in-person and on-line versions. In future studies, in addition to examining scores on the IFI-BR for fathers in contexts that may negatively affect the quality of their paternal involvement, efforts are also needed to capture information about the psychometric properties of the items and evidence based on: (a) criterion validity, (b) experimental and quasi-experimental studies, (c) response processes, and (d) consequences of testing. This instrument, combined with greater knowledge about interpersonal processes related to father involvement, in Brazil, will contribute to the quality of research work and professional interventions to support father involvement.
A società Dante Alighieri: um estudo de caso sobre o associativismo étnico italiano em São Carlos/SP – 1902 a 1938
(Universidade Federal de São Carlos, 2020-03-13) Conceição, Carla Fernandes da; Truzzi, Oswaldo Mário Serra; https://lattes.cnpq.br/5005536921435787; https://lattes.cnpq.br/9305606827299303
The present PhD thesis has the objective of analyzing the associationism practice by the Italian immigrants in the São Carlos, São Paulo State, in the years of 1902 through 1938, by understanding the activities of “Dante Alighieri” Italian Society. With this aim, the study is based on comprehending the society as a social space in which the Italian immigrant builds its ethnic identity, associating the mechanisms and strategies of incorporation to the host society upon its professional, economical, cultural, educational and social capitals. The director members of the society, president and vice-president will have a focus in the present study, based on the analysis of regional, professional, educational trajectories, in relation to the fascism and the construction of individual and associativist trajectories. The source of the study is based on several documents, mainly on minutes from ordinary meetings and board meetings of the studied society, complemented by the analysis of the articles of incorporation of the society, as well as local newspapers at the time, city Almanac, in the Municipal census of 1907, marriage certificates, books, journal articles, thesis and dissertations. The present research then prioritizes a qualitative analysis but does not disregard the use of qualitative documents. In the end, the present study will contribute to understand the associationism practices of Italian immigrants in São Carlos, by using the Dante Alighieri Italian Society as a case study, which so far has been a theme not well covered in the literature.
Modelos de sobrevivência bivariados baseados na cópula PVF
(Universidade Federal de São Carlos, 2020-03-13) Biondo, Thiago Ramos; Suzuki, Adriano Kamimura; https://lattes.cnpq.br/4579497412852854; https://lattes.cnpq.br/6278031837756816
An alternative developed to study associations among multivariate survival times is the use of models based on copula functions. In this work, we use the survival model derived from the PVF copula, based on the Power Variance Function distribution, to model the dependence of bivariate data in the presence of covariates and censored observations. For inferential purposes, we perform a Bayesian approach using Monte Carlo Markov Chain (MCMC) methods. Some discussions about model selection criteria are presented. In order to detect influential observations, we used the Bayesian method of deletion influence analysis of cases based on divergence psi. Finally, we show the applicability of the proposed models to simulated and real datasets.
Formulações à base de Bacillus spp., para controle de Alternaria alternata f.sp citri
(Universidade Federal de São Carlos, 2020-03-13) Moura, Álisson Queiroz; Correa, Élida Barbosa; https://lattes.cnpq.br/3308762941982851; Kupper, Katia Cristina; https://lattes.cnpq.br/7900622063392740; https://lattes.cnpq.br/2123150174811729
In the 2018 harvest, Brazil produced 996.872 tons of tangerines and their hybrids, with the state of São Paulo and Minas Gerais responsible for 59% of this production. However, this productive potential requires the use of a high number of fungicide applications to control one of the main phytosanitary problems, an Alternaria Brown Spot (ABS), caused by the fungus Alternaria alternata f.sp citri. However, the results, besides it not being entirely satisfactory, can have a negative impact on health and the environment. The insertion of alternative methods, such as biological control, can be a efficient and socially correct strategy for controlling the disease. Therefore, the present study aimed to develop Bacillus subtilis (ACB-01) and B. amyloliquefaciens (ACB-08) based formulations, which in previous studies showed potential for controlling ABS. For this, it was evaluated: (i) the addition of nitrogen compounds and trace elements on the antagonistic activity from bacteria; (ii) the use of different carrier materials (talc, kaolin and starch) in the formulation; (iii) the shelf life of Bacillus spp.-based formulations, in two storage conditions (22 and 4 ° C); (iv) the effect of formulations on mycelial growth and germination of A. alternata conidia and, finally, (v) the efficiency of Bacillus spp.-based formulations, in the control of the disease. The results obtained showed that: most of the evaluated additives favored the antagonism of the bacterial isolates, affecting the mycelial development of the phytopathogen; the combination of a nitrogenous compound and a trace element showed a lower antagonistic activity of the bacteria, when compared with the additives used individually; all Bacillus spp.-based formulations, regardless of the bacterium carrier material, were efficient in inhibiting the germination and development of the A. alternata colony; most formulations remained viable until six months of storage at 22 oC; B. amyloliquefaciens ACB-08-based formulations did not maintain viability when stored for six months at 4 oC; there was a difference regarding the preference of additive and carrier material for the development of formulations from Bacillus species; the best formulations for Alternaria Brown Spot control included: B. subtilis ACB-01 grown with MnSO4.H2O (1mM) + kaolin and B. amyloliquefaciens ACB-08 grown with CoCl2.12H20 (0.2mM) + talc and they were compatible with strobilurin, when applied in mixture.
Validação do “Sarcopenia and Quality of Life” (SarQoL ® ) para o contexto brasileiro
(Universidade Federal de São Carlos, 2020-03-13) Nunes, Juliana Duarte; Orlandi, Fabiana de Souza; https://lattes.cnpq.br/7395879552721664; https://lattes.cnpq.br/5634548433598863
Introduction: Sarcopenia is a chronic condition associated with the physiological aging process and is defined by the reduction of muscle mass, strength and function. Recently, a specific quality of life assessment instrument for people with sarcopenia called Sarcopenia and Quality of Life (SarQoL® ) was created and its Brazilian version has already been translated and adapted, with the validation stage missing for the availability of the instrument in Brazil. Objective: to validate the instrument “Sarcopenia and Quality of Life” (SarQoL® ) in Brazil with elderly people in the community. Methodology: this was a methodological study to validate SarQoL® in Brazil and for this process, the steps recommended by the authors of the SarQoL® instrument were followed. Respecting the inclusion and exclusion criteria previously established, the elderly were invited to participate in the study by telephone and once accepted, an individual interview was conducted, with the application of SarQoL® , from the Medical Outcomes Study 36 - Item Short Form Health Survey (SF-36), EuroQol-5D (EQ-5D), Mini Nutritional Assessment (MAN), Mini Mental State Examination (MMSE) and Geriatric Depression Scale (GDS). For the diagnosis of sarcopenia, the procedure recommended by the Second European Sarcopenia Consensus (EWGSOP2) published in 2019 was followed, in which initially muscle strength is checked (in this study, hand grip strength was used), and to confirm sarcopenia, muscle mass (verified in this study by DXA). The study was formally authorized and approved by the Research Ethics Committee of the Federal University of São Carlos - UFSCar under opinion n.637.779 / 2016. Results: of the 221 elderly participants in the survey, 68.3% were women (n = 151), with an average schooling of 5.4 years, 163 participants were white (73.8%) and 61.1% were married (n = 135). Regarding sarcopenia, 55 elderly people presented sarcopenia according to the criteria of the EWGSOP2. Among the psychometric properties that were verified for the validation of the Brazilian version of SarQoL® , there is reliability, through the internal consistency verified by Cronbach's alpha coefficient, in which the total of SarQoL® was 0.976, indicating excellent internal consistency, and also by the test-retest, verified by means of the intraclass correlation coefficient (ICC), in which the ICC of 0.983 (95% CI 0.901-0.996) was observed in the total SarQoL® , also demonstrating good reliability. In construct validity, SarQoL® was correlated with SF-36 and EQ-5D, generally identifying a positive correlation of moderate to strong magnitude and all correlations were statistically significant. In the discriminant validity, the quality of life of patients with and without sarcopenia was compared, with the elderly with sarcopenia having an average total score of 55.57, compared to a score of 73.94 in the elderly without sarcopenia. All elderly people with sarcopenia had lower scores in all domains of SarQoL® , as well as in total, and all values had a significant p-value, showing good discriminant validity. Conclusion: Based on the proposed objective and the results obtained, it can be concluded that SarQoL® has evidence of reliability and validity. SarQoL® translated, adapted and validated in the Brazilian context is available for use in Brazil.
Efeito da associação da fotobiomodulação e exercício físico em mulheres com osteoartrite de joelho sobre o nível de dor: ensaio clínico placebo-controlado randomizado duplo-cego
(Universidade Federal de São Carlos, 2020-03-13) Pelloi, Suzana Cristina Pereira; Renno, Ana Claudia Muniz; https://lattes.cnpq.br/4106611304688552; https://lattes.cnpq.br/5391906649812193
OA is a degenerative disease with joint signs and symptoms associated with changes in the integrity of the articular cartilage, remodeling of the subchondral bones and local and adjacent tissue inflammation, clinically associated by joint pain and functional limitation. Pain is the biggest disabling factor, so it is important to investigate ways to improve it, and photobiomodulation (PBM) has been highlighted for promoting modulation of the inflammatory process and relief of pain of OA. The objective of this study was to verify whether the gradual increase in the dosage of FBM applied to the knee joint has more positive effects in the treatment of OA when combined with physical exercise, especially in relation to pain. Twenty-eight women, between 55 and 75 years old, with knee OA grades II and III, were allocated to the Physical Exercise Group associated with active PBM (PEAP), who received treatment with an eight-week exercise protocol associated with active irradiation of PBM and Physical Exercise Group associated with Placebo PBM (PEPP), which received the same treatment, but with placebo irradiation. PBM was performed with an 808nm laser, applied to the medial and lateral regions of the knee. The instruments used were (for assessment and reassessment) the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire, Visual Analogue Scale (VAS), digital algometer, Timed Up-and-Go Test (TUGT) and 6-minute walk test (6-MWT). The results obtained showed that there was an improvement in pain, symptoms and functionality in both groups, with no significant difference between them. It can be concluded that the exercise program was able to reduce the level of pain and increase the functional capacity of women affected by knee OA. However, the PBM used in the treatment regimen, with a progressive increase in the dose, did not optimize the positive results of the exercise program.
Custos de transação e colaboração entre agentes públicos e setor privado sob a ótica das construtoras no Programa Minha Casa Minha Vida em municípios paulistas
(Universidade Federal de São Carlos, 2020-03-13) Danelon, Leonardo; Paulillo, Luiz Fernando de Oriani e; https://lattes.cnpq.br/9919942357089937; https://lattes.cnpq.br/5972083655911627
There are a variety of studies discussing the issue of production costs in the housing construction sector. However, as a product that usually envolves coletive interests, there are a set of stages of approvals with the public sector that should be considered as costs. As an example, longer approval periods caused by public sector may interfere in the internal rate of return (IRR) of the project (which may render them unfeasible), exposing a typical situation that generates transaction cost for the operation. As a result, this thesis proposes to dimension the main triggers of transaction costs present in the flow of approvals of construction companies' projects with the public bureaucracy, under the perspective of construction companies. The attributes of the transaction costs proposed by Oliver Williamson were adopted as a theoretical framework: the asset specificity, uncertainty (via the concepts of adverse selection and moral hazard) and frequency. Due to its social function and importance regarding the use of public resources, it was opted for the analysis of these attributes in the project approval relationships for the Programa Minha Casa Minha Vida (PMCMV, 1 - FAR). The research is also completed with some elements of the collaborative production chain methodology for verify how jointly articulated are the actions of the government and private sector in these ventures. The project approval process was mapped to create a research that would cross each step of the approval process with each attribute of the transaction, in such a way to dimension them and identify the most critical points and their causes. It was observed - within the adopted methodology, for the observed aspects and in the evaluated enterprises - that the MCMV stimulated some articulation and coordination of actions from different state spheres (municipalities, state and Union), as well as promoting collaboration between municipalities and construction companies in favor of a common goal. From the point of view of transaction costs, the financial agent (intermediary between the FAR and construction companies) came to assume the greatest relevance due to the moral hazard associated with delays in the transfer of resources to the construction companies.
Considerando alterações climáticas na escolha de áreas para conservação de serpentes na região hidrográfica Tocantins-Araguaia
(Universidade Federal de São Carlos, 2020-03-13) Pelegrini, Sóstenes José Souza; Lemes, Priscila; https://lattes.cnpq.br/7228776843625214; São Pedro, Vinícius de Avelar; https://lattes.cnpq.br/7404103190291423; https://lattes.cnpq.br/0138298166376301
One of the most effective ways to preserve biodiversity in situ is through the creation of protected areas. The expansion of the network of protected areas is crucial for efforts to conserve biodiversity to be optimized in suitable areas. To this end, it is important that new areas are chosen with clear criteria - for example, high diversity and level of endemism. It is increasingly important to consider the current global climate changes, as there is evidence that many species change their current range in response to new climatic conditions. Here, we seek to indicate which are the best areas for the conservation of snakes in the Tocantins-Araguaia Hydrographic Region, an area of great biological importance, but also increasingly threatened by human activities. We considered two climate change scenarios, an optimistic and a pessimistic one (RCP 45 and RCP85) and generated ecological niche models for the entire snake community in the region. Finally, using the generated models, the network of existing conservation units and the percentage of native vegetation obtained through MAPBIOMAS, we point out the most climatically stable areas as the most suitable for the conservation of snakes in this basin. For this we use the Zonation software. In our results, we observed that most of these areas are concentrated south of the study region, coinciding with the largest current gap in protected areas in this basin.
Modelos de sobrevivência induzidos por fragilidade discreta série de potência zero-modificada
(Universidade Federal de São Carlos, 2020-03-13) Molina, Katy Rocio Cruz; Calsavara, Vinicius Fernando; https://lattes.cnpq.br/2500432593240959; Tomazella, Vera Lucia Damasceno; https://lattes.cnpq.br/8870556978317000; https://lattes.cnpq.br/8820054149005701
Survival models with a frailty term are presented as an extension of Cox's proportional risk model (COX, 1972), in which a random effect, called frailty, is introduced in the risk function in a multiplicative way with the aim of modeling the unobserved heterogeneity from the units under study. The distribution for the frailty variable is assumed to be continuous and not negative. However, there are some situations it is appropriate to consider discretely-distributed frailty, for example, when heterogeneity in lifetimes arises because of the presence of a random number of flaws in a unit or because of exposure to damage on a random number of occasions. In this work, we developed different frailty models applying some distributions belonging to Zero-Modified Power Series (ZMPS) family. In this context, with the use of the ZMPS distribution for frailty, we can notice the possibility of individuals with zero frailty, which corresponds to a limited failure model that contains a proportion of units that never fail (long-term survivors) or cure fraction model. The proposed model is applied to a set of real melanoma data.
Influência dos contornos de grãos nas propriedades elétricas de hematita policristalina modificada com diferentes elementos químicos
(Universidade Federal de São Carlos, 2020-03-13) Destro, Fabrício Benedito; Leite, Edson Roberto; https://lattes.cnpq.br/1025598529469393; https://lattes.cnpq.br/3501169439113813
The use of molecular hydrogen produced by photoelectrochemical cells is an alternative to fossil fuels, economically and environmentally. Hematite (α-Fe2O3) is a promising candidate to the realization of photoelectrochemical water splitting, by having low bandgap, chemical stability and low cost. However, disadvantages as low electrical conductivity and low lifetime of photogenerated holes harm its theoretical efficiency. Literature has emphasized the production of nanostructured and/or modified hematite photoelectrodes aiming to get around such negatives, but due to the great number of interfaces present in the system, there is not a quali or quantitative control in the contribution of each one on the efficiency loss. Therefore, is proposed a study with a simplified model, using a polycrystalline ceramic body modified with many cations (Sn, B, Ti, Zn, Zr and Sb), sintered at two temperatures, to verify the effect of grain boundaries, besides the different kinds of modifiers, on the electrical properties of hematite. The samples produced showed high relative density, besides different electric behaviors due to the different defects formed by the insertion of modifiers. In the case of modifications with Sn, it was formulated the hypothesis of the separation in two distinct grain boundary populations, as the sintering temperature gets larger. One of the components have a larger relaxation time, which translates into a larger electrical resistance. Ti and Zr present similar behaviors as Sn. B did not present any enhancement, probably because its valence remains the same as iron. Zn, however, induced the formation of a secondary dielectric phase. Sb was appropriated to enhance hematite’s electrical conductivity, although the presence of a secondary phase limits its application. However, the system also presented a grain bounday component with high relaxation time, acting as a limiter of the conductivity.