Estimação clássica e Bayesiana em modelos de sobrevida com fração de cura

In Survival Analysis, long duration models allow for the estimation of the healing fraction, which represents a portion of the population immune to the event of interest. Here we address classical and Bayesian estimation based on mixture models and promotion time models, using different distributions (exponential, Weibull and Pareto) to model failure time. The database used to illustrate the implementations is described in Kersey et al. (1987) and it consists of a group of leukemia patients who underwent a certain type of transplant. The specific implementations used were numeric optimization by BFGS as implemented in R (base::optim), Laplace approximation (own implementation) and Gibbs sampling as implemented in Winbugs. We describe the main features of the models used, the estimation methods and the computational aspects. We also discuss how different prior information can affect the Bayesian estimates

Os significados do tabagismo construídos na dinâmica social

The present study has the purpose of catching the significances of smoking in the social dinamics based on the Theory of Social Representations. It was developed among adults with ages from 20 to 59 years, low social and economic conditions, at Natal RN, Brazil. The Free-words Association Test was applied as the instrument of data collection and a semi-structured interview with the smokers and non-smokers, besides a structured interview with smokers, non-smokers and ex-smokers. All data was analyzed by the descriptive statistics using the Analysis of Content Technique of the thematic kind and by the softwares ALCESTE and EVOC 2000. Elaborations about smoking were marked by social, cultural and historical dimension, however they showed sensibility to changes and revealed positive and negative aspects of the habit. The analysis of the semi-structured interviews showed the following categories and under-categories respectively: Initiation of the habit (Friends and Family and Appreciation and Beauty); Psychosocial Implications of smoking (Personal relationship, Work and Financial); Behavior when facing smoking (Positive, Negative and Neutral); Smoking Effects (Smokers´ health and the other people health); Description about oral diseases ( Bad breath, Oral cancer and Dental problems); Smoking treatment (Physician and psychological, Supernatural and Difficulties). ALCESTE analysis presented 4 classes: Ambivalence between pleasure and get ill, Smoking as a trouble and danger to society, Social discrimination of smokers and Mouth as a place of reaffirmation of the discrimination. Those helped us to understand the psychosocial repercussion of the habit. On the social representation structure we identified as a probable central nucleus of the smoker group the categories Pleasure and Bad to the health and as peripheral elements Alcoholic Drink, Financial damage and Nervousness. For the non-smoker group the category Bad to the health comes first and Stop Smoking comes as a peripheral element. Finally, we hope that the knowledge of these representations can contribute to plan and/or to rethink over the professional practices and public policies related to smoking. Besides that, for an amplified comprehension of the study object the discussions over the identified representations should be deepen and amplified to other population and social groups

Maternidade na adolescência: significados e repercussões

From evidence of an existing divergence of opinion among professionals and adolescents using the prenatal and delivery services at a Public Health Unit, aimed to study meanings and consequences of adolescent motherhood among 26 adolescent mothers living in Felipe Camarão, low income district of Natal, capital do Estado do Rio Grande do Norte. Living in a peripheral neighbourhood with a high rate of adolescent mothers in relation to the total new-born, those girls, with offspring among 8 and 12 months age, during interview and focus groups, expressed a different appreciation of their experience than the hegemonic idea among professionals that considers pregnancy and motherhood as unwanted or undesired. With age among 15 and 20 years old, having 53,8% initiated sexual activity before being 15 years old, revealed that the pregnancy was desired in 73,1% of cases, but showing at the same time a social context marked by strong gender oppression and lack of opportunities as consequence of social class deprivation. Life projects, almost always limited to the constitution of a traditional nuclear family, with a purveyor father and care giver mother, appears with very limited possibilities: 46,2% already lived with her partner before becoming pregnant and for 50% of the participants, the birth of the child did not provoke changes in plans and projects. Lack of economical recourses and precarious public services available, together with an idealized maternity role seems to produce extra apprehension among those girls, resulting in frustration and disillusion. As a fact, 92,3% of those adolescents would recommend other adolescent to postpone the maternity project

A experiência de adolescentes portadores de diabetes Mellitus Tipo 1: seus significados e sentido

Worldwide, the diabetes mellitus is considered a serious problem of public health; it also involves high costs for its treatment and its complications. Even though the onset of diabetes mellitus type 1 is on 5% to 10% of the diabetic population, it is the most aggressive type of anifestation; furthermore, it is the commonest chronic disease in childhood and adolescence. Such data show the importance of understanding the development of this disease from the moment the individual perceives it, according to their experience, observing the complexity of the phenomenon thoroughly. This study aimed to comprehend the experience of the adolescent with onset of diabetes mellitus type 1 in order to learn how these young individuals perceive and reason their place in the world when they experience this illness. The methodological strategy was based on qualitative research of phenomenological inspiration. We applied the main ideas of heideggerian ontology and some concepts of existential phenomenological psychology to guide our reflexive path. The participants were 10 young individuals (06 female and 04 male), ages between 15 and 18, under treatment in the city of Recife, Pernambuco. The methodological resource was the narrative, which allowed us access to the adolescents experience. The comprehension of the reports was based on the heideggerian hermeneutics, whose priority is the interpretation of the meaning expressed by the participants speech. The results showed that factors such as social, family, economic and cultural context greatly influence the perception and the way the individuals deal with, perceive and reason their experience. We noticed that the diabetes type 1 may often represent a limitation, but it does not make it impossible to be part of the world with others. The data show a significant affective ambivalence regarding the content more directly related to the disease. This demonstrates the unique way which each one gives meaning and reasons their condition of existence. This research points out the need to understand the complexity of this phenomenon in a more complete manner, considering the adolescent in their timely and historical context. We believe we can encourage thinking that may become actions which are more fit to the reality researched regarding all the parties involved with the subject, such as health professionals, adolescents, family, support programs and public health policies

Significados de família para crianças em abrigo

This research explores the meanings of family for institutionalized children. It identifies, more specifically, how the relationship between the child and his/ her family is. The field work was developed at a municipal shelter in Natal/RN, which houses children aged between 7 and 11 years old. The subjects of research consisted of three children: two boys and one girl. Besides age-group criterion, which facilitates the use of oral language and the procedures, we took into consideration another selection criterion: children whose family configurations were similar. In order to achieve the objectives, we used toys, pictures, collages and semi-structured interviews. Data were examined under the Thematic Content Analysis, with three thematic categories previously chosen: Configuration of geographic area, family composition and family s internal dynamics. Among the results, we highlight that, for children, the concept of family is based essentially on existence of affection ties, regardless of kinship. Through this study, we hope to contribute to the discussion on the rights of institutionalized children, concerning their need of experiencing family life and living in community

Os significados de ludoterapia para as protagonistas do processo: crianças em atendimento

The ludic therapy in a Phenomenological-Existential perspective is conceived as a psychotherapeutic process in which, the listening and talking, mediated by playing activities, allow the child to deal with their grief/suffering. This study is based on the need to broaden the understanding of this modality of clinical intervention by emphasizing the speech of the protagonists in the process: children in therapy. The objective was to understand the ludic therapy from the children s perspective, knowing the meanings assigned to the therapeutic process, to the psychologist and to the involvement of the children in clinical consultations. The main ideas that underlie this research are presented in three theoretical chapters covering, respectively, the suffering of children and the demand for psychotherapy, the Phenomenological-Existential clinical psychology, and the psychotherapy for children, in Brazil, under this theoretical-methodological approach. The study was qualitative, on a phenomenological basis, and included six children as participants, aged between six and ten years, undergoing ludic therapy for at least six months, and referred by their own therapists. In the research s corpus construction, individual meetings were held and mediated by tools to support expressiveness (ludic and pictures/figures boxes), added by the storytelling of an incomplete story about a child s visit to the therapy session, and the request for the elaboration of a message to be passed to a child who will go to see a psychologist. The analysis of the data was based on a variant of the phenomenological method proposed by Amedeo Giorgi. The results reveal a lack of knowledge by the children about the psychologist s activities. Thus, the children develop fantasies about this intervention modality because of lack of information. These observations are consistent with the historical meanings assigned to clinical psychology, involving ideas of normality and guilt. The meanings associated with the motives for a referral to a psychologist highlight the conflict "be a problem versus having a problem" and an elitist conception of clinical psychology. Children understand the characteristics of the therapeutic process, such as the specifics of the therapist-client relationship and the notion of freedom. They also demonstrate remarkable pleasure in the therapeutic process. Finally, it was concluded that the meanings attributed to the ludic therapy by the children are consistent with that proposed in the literature about the children s psychotherapy process in the Phenomenological-Existential perspective. Moreover, the relevance of both the children s experience in the therapeutic setting and the meanings of these proceedings understood by the children are highlighted by the listening to the protagonists in the ludic therapeutic process. The comprehension of these aspects and their transference from the clients experience to the reflective field, promote advances in the understanding of child psychotherapy and indicate the need for further studies with children using this approach.

Significados de família para adolescentes em liberdade assistida

Guided by the social-historical perspective, this research aimed to understand how the adolescents in Assisted Freedom measure have meaning the family institution. The Pastoral Minor, located in the city of Natal, was chosen as space of investigation, whose social-educative program is the source of our concerns about the attendance of adolescents in conflict with law. The corpus was accomplished, mainly, through the individual semi- structured interview with four adolescents and seven of their relatives that participated of the research. We use another instruments to constitute the corpus, like the documental research of the technical reports on the participants of program files, and the registered notes in the field diary. As resource to data treatment, we use the Thematic Content Analysis. The data discussion was focused on the three thematic units that emerged: Family, Social-Educational Measure, Family and Social-Educational Measure. On the adolescents perspective, the family configures as a group based on the existence of affective bonds. Despite of the vulnerability of their familiar reality and their wish for freedom with their peers, the affective bonds revealed it as being important in their lives. This study, glimpse possibilities to contribute for the construction of public politics and attendance programs, that can be closer of the social-familiar reality of the adolescents who are in conflict with the law and, in this case, to promote their access to the statute of subjects of rights

Extração e análise da fração lipídica da microalga monoraphidium sp., síntese e caracterização do seu biodiesel

The cultivation of microalgae biomass in order to produce biodiesel arises as an extremely promising aspect, in that the microalgae culture includes short cycle of reproduction, smaller areas for planting and residual biomass rich in protein content. The present dissertation evaluates the performance and features, through spectrometry in the region of infrared with transformed Fourier (FTIR) and spectrometry in the region of UVvisible (UV-Vis), of the extracted lipid material (LM) using different techniques of cell wall disruption (mechanical agitation at low and at high spin and agitation associated with cavitation). The technique of gas chromatography (GC) brought to light the success of alkaline transesterification in the conversion of oil into methyl monoesters (MME), which was also analyzed by spectroscopic techniques (FTIR, proton magnetic resonance (1H NMR) and carbon (13C NMR). Through thermogravimetric analysis (TGA) were analyzed the lipid material (LM), biodiesel and the microalgae biomass. The method which provided the best results concerning the efficiency in extraction of the LP of Monoraphidium sp. (12,51%) was by mechanical agitation at high spin (14 000 rpm), for 2 hours being the ideal time, as shown by the t test. The spectroscopic techniques (1H NMR, 13C NMR and FTIR) confirmed that the structure of methyl monoesters and the chromatographic data (CG) revealed a high content of saturated fatty acid esters (about 70%) being the major constituent eicosanoic acid (33,7%), which justifies the high thermal stability of microalgae biodiesel. The TGA also ratified the conversion rate (96%) of LM into MME, pointing out the quantitative results compatible with the values obtained through GC (about 98%) and confirmed the efficiency of the extraction methods used, showing that may be a good technique to confirm the extraction of these materials. The content of LM microalgae obtained (12,51%) indicates good potential for using such material as a raw material for biodiesel production, when compared to oil content which can be obtained from traditional oil for this use, since the productivity of microalgae per hectare is much larger and requires an extremely reduced period to renew its cultivation

Avaliação de uma fração polissacaridica da alga Lobophora variegata (Lamouroux) em modelo de artrite induzida em ratos por Zymosan

Fucans seaweed Lobophora variegata estructures are known for their chemical and biological properties. In this study, we analyzed, the action of fucans L. variegata and the fractions purified with acetone in Zymosan-induced arthritis. After differential fractionation with acetone, six fractions were obtained and named F0.3, F0.5, F0.8, F1, F1.5 and F2. The results showed that the fraction F1 showed high yield (51.9%) and was chosen for studies of antioxidant activity and induced arthritis. Nuclear magnetic resonance (NMR) of 13C showed signals at 103.3 and 15.78 ppm that are assigned to links β13 galactose and of the C6 methyl fucose, respectively. The infrared (IR) showed absorbance at 1238 and 850 cm-1 which are attributed to sulfate. The fraction F1 showed antioxidant activities in vitro. For analysis of inflammatory parameters chosen the polysaccharide was administered in different doses (25, 50 and 75 mg / kg ip, per body weight) and diclofenac sodium (5 mg / kg ip) and L-NAME (25 mg / kg ip) in groups of animals (n = 6). After 6 h, were analyzed for cellular influx and levels of nitrite. In experiment five days, were made analysis of swelling and serum TNF-α. Histopathological analysis were performed for confirmation of results. The fraction F1 (25, 50 and 75 mg / kg ip) reduced the cellular influx (52.1 to 96.7%) and nitric oxide levels (27.2 - 39%) compared to control group. The reduction of edema (63.4 - 100%) and serum TNF-α (p <0.001) were observed when the polysaccharide F1 administered at a dose (50 mg / kg) These results suggest that these heterofucanas of Lobophora variegata have besides the activity antioxidant and potential anti-inflammatory activity in arthritis induced by zymosan

Modelo de tempo de falha acelerado com fração de cura : uma abordagem unificada

In this work we study the accelerated failure-time generalized Gamma regression models with a unified approach. The models attempt to estimate simultaneously the effects of covariates on the acceleration/deceleration of the timing of a given event and the surviving fraction. The method is implemented in the free statistical software R. Finally the model is applied to a real dataset referring to the time until the return of the disease in patients diagnosed with breast cancer

Testes de hipóteses em modelos de sobrevivência com Fração de cura

Survival models deals with the modeling of time to event data. However in some situations part of the population may be no longer subject to the event. Models that take this fact into account are called cure rate models. There are few studies about hypothesis tests in cure rate models. Recently a new test statistic, the gradient statistic, has been proposed. It shares the same asymptotic properties with the classic large sample tests, the likelihood ratio, score and Wald tests. Some simulation studies have been carried out to explore the behavior of the gradient statistic in fi nite samples and compare it with the classic statistics in diff erent models. The main objective of this work is to study and compare the performance of gradient test and likelihood ratio test in cure rate models. We first describe the models and present the main asymptotic properties of the tests. We perform a simulation study based on the promotion time model with Weibull distribution to assess the performance of the tests in finite samples. An application is presented to illustrate the studied concepts

A distribuição F generalizada para selecionar modelos de sobrevivência com fração de cura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Paisagem arquitetônica da cidade de João Pessoa/PB e seus significados: o perceptivo dos moradores

This study was conducted in the city of João Pessoa, Paraíba mesoregion Forest. Having to analyze how does the appreciation of the architectural heritage to the visitor and pessoense Capital Paraiba, taking into account the narratives of João Pessoa, and practitioners of foreign tourists of cultural tourism. This research builds on a theoretical foundation on concepts of landscape and place. Was taken as a foundation to Cultural Geography. The research in question is justified by embarking on Geography and Heritage and cast a glance on the geographical cultural landscape, trying to unravel the symbols assigned to the ancient architectural examples, meaning that interfere with power relationships that cross generations, constructing and deconstructing identities, is dispersed or integrating cultures, creating cultural groups and social conflict. It is concluded that the geographical area derives from a number of factors, among them the culture and this in turn will shaping the landscape, reflecting the abstract over the concrete architecture of the oldest to the most current, turning from the material to the immaterial in World Heritage Site

Avaliação e correções de testes de hipóteses em modelos de sobrevivência com fração de cura

Survival models deals with the modelling of time to event data. In certain situations, a share of the population can no longer be subjected to the event occurrence. In this context, the cure fraction models emerged. Among the models that incorporate a fraction of cured one of the most known is the promotion time model. In the present study we discuss hypothesis testing in the promotion time model with Weibull distribution for the failure times of susceptible individuals. Hypothesis testing in this model may be performed based on likelihood ratio, gradient, score or Wald statistics. The critical values are obtained from asymptotic approximations, which may result in size distortions in nite sample sizes. This study proposes bootstrap corrections to the aforementioned tests and Bartlett bootstrap to the likelihood ratio statistic in Weibull promotion time model. Using Monte Carlo simulations we compared the nite sample performances of the proposed corrections in contrast with the usual tests. The numerical evidence favors the proposed corrected tests. At the end of the work an empirical application is presented.

Modelos flexíveis de sobrevivência com fração de cura: implementação computacional

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)