181 research outputs found

    Spatial-temporal analysis of breast cancer in upper Cape Cod, Massachusetts

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    INTRODUCTION. The reasons for elevated breast cancer rates in the upper Cape Cod area of Massachusetts remain unknown despite several epidemiological studies that investigated possible environmental risk factors. Data from two of these population-based case-control studies provide geocoded residential histories and information on confounders, creating an invaluable dataset for spatial-temporal analysis of participants' residency over five decades. METHODS. The combination of statistical modeling and mapping is a powerful tool for visualizing disease risk in a spatial-temporal analysis. Advances in geographic information systems (GIS) enable spatial analytic techniques in public health studies previously not feasible. Generalized additive models (GAMs) are an effective approach for modeling spatial and temporal distributions of data, combining a number of desirable features including smoothing of geographical location, residency duration, or calendar years; the ability to estimate odds ratios (ORs) while adjusting for confounders; selection of optimum degree of smoothing (span size); hypothesis testing; and use of standard software. We conducted a spatial-temporal analysis of breast cancer case-control data using GAMs and GIS to determine the association between participants' residential history during 1947–1993 and the risk of breast cancer diagnosis during 1983–1993. We considered geographic location alone in a two-dimensional space-only analysis. Calendar year, represented by the earliest year a participant lived in the study area, and residency duration in the study area were modeled individually in one-dimensional time-only analyses, and together in a two-dimensional time-only analysis. We also analyzed space and time together by applying a two-dimensional GAM for location to datasets of overlapping calendar years. The resulting series of maps created a movie which allowed us to visualize changes in magnitude, geographic size, and location of elevated breast cancer risk for the 40 years of residential history that was smoothed over space and time. RESULTS. The space-only analysis showed statistically significant increased areas of breast cancer risk in the northern part of upper Cape Cod and decreased areas of breast cancer risk in the southern part (p-value = 0.04; ORs: 0.90–1.40). There was also a significant association between breast cancer risk and calendar year (p-value = 0.05; ORs: 0.53–1.38), with earlier calendar years resulting in higher risk. The results of the one-dimensional analysis of residency duration and the two-dimensional analysis of calendar year and duration showed that the risk of breast cancer increased with increasing residency duration, but results were not statistically significant. When we considered space and time together, the maps showed a large area of statistically significant elevated risk for breast cancer near the Massachusetts Military Reservation (p-value range:0.02–0.05; ORs range: 0.25–2.5). This increased risk began with residences in the late 1940s and remained consistent in size and location through the late 1950s. CONCLUSION. Spatial-temporal analysis of the breast cancer data may help identify new exposure hypotheses that warrant future epidemiologic investigations with detailed exposure models. Our methods allow us to visualize breast cancer risk, adjust for known confounders including age at diagnosis or index year, family history of breast cancer, parity and age at first live- or stillbirth, and test for the statistical significance of location and time. Despite the advantages of GAMs, analyses are for exploratory purposes and there are still methodological issues that warrant further research. This paper illustrates that GAM methods are a suitable alternative to widely-used cluster detection methods and may be preferable when residential histories from existing epidemiological studies are available.National Cancer Institute (5R03CA119703-02); National Institute of Enviornmental Health (5P42ES007381

    Method for mapping population-based case-control studies: an application using generalized additive models

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    BACKGROUND: Mapping spatial distributions of disease occurrence and risk can serve as a useful tool for identifying exposures of public health concern. Disease registry data are often mapped by town or county of diagnosis and contain limited data on covariates. These maps often possess poor spatial resolution, the potential for spatial confounding, and the inability to consider latency. Population-based case-control studies can provide detailed information on residential history and covariates. RESULTS: Generalized additive models (GAMs) provide a useful framework for mapping point-based epidemiologic data. Smoothing on location while controlling for covariates produces adjusted maps. We generate maps of odds ratios using the entire study area as a reference. We smooth using a locally weighted regression smoother (loess), a method that combines the advantages of nearest neighbor and kernel methods. We choose an optimal degree of smoothing by minimizing Akaike's Information Criterion. We use a deviance-based test to assess the overall importance of location in the model and pointwise permutation tests to locate regions of significantly increased or decreased risk. The method is illustrated with synthetic data and data from a population-based case-control study, using S-Plus and ArcView software. CONCLUSION: Our goal is to develop practical methods for mapping population-based case-control and cohort studies. The method described here performs well for our synthetic data, reproducing important features of the data and adequately controlling the covariate. When applied to the population-based case-control data set, the method suggests spatial confounding and identifies statistically significant areas of increased and decreased odds ratios

    Matemática no ensino secundário e a flexibilidade curricular: atividades desenvolvidas com os alunos

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    A introdução do projeto da autonomia e flexibilidade curricular no ensino português suscitou dúvidas e receios nas comunidades escolares que teriam de o implementar. Este trabalho tem como objetivo contribuir com propostas de respostas a dúvidas e receios dos professores. É apresentada a implementação do projeto da autonomia e flexibilidade curricular em turmas lecionadas pelo autor, nas disciplinas de Matemática Aplicada às Ciências Sociais, Matemática B e Matemática A, nos anos letivos 2017/2018 a 2019/2020, com fundamentação legal e científica - pedagógica para o trabalho desenvolvido. A contribuição do autor para o ensino da Matemática no Ensino Secundário no âmbito do projeto da autonomia e flexibilidade curricular traduz-se na criação de tarefas matemáticas contextualizadas nos interesses e na vida diária dos alunos na comunidade local; numa reflexão sobre o desenrolar da implementação do projeto, destacando aspetos positivos e negativos; e numa análise estatística da repercussão da implementação do projeto nas classificações internas e externas dos alunos das turmas visadas. Conclui-se que a implementação apresentada do projeto da autonomia e flexibilidade curricular foi uma mais valia para professor e alunos, proporcionando um leque alargado de novas aprendizagens de acordo com o Perfil dos Alunos à Saída da Escolaridade Obrigatória. Em termos de avaliações internas e externas, os alunos que usualmente têm classificações mais baixas melhoraram as suas classificações, não se observando diferenças significativas nas classificações dos alunos que usualmente já têm boas classificações.The introduction of the project of autonomy and flexibility of the curriculum in the Portuguese schooling system raised doubts and apprehension in the school communities in which the project would be implemented. The objective of this work is to contribute with proposals for answers to doubts and apprehensions of the teachers. The document presents the implementation of the project of autonomy and flexibility of the curriculum in the classes taught by the author, along with its legal and scientific-pedagogical support. The subjects Mathematics Applied to Social Sciences, Mathematics B and Mathematics A were taught in the school years 2017/2018 through 2019/2020. The author's contribution to the teaching of Mathematics in Secondary Education within the scope of the project of autonomy and flexibility of the curriculum consists of the creation of mathematical tasks contextualized in the interests and daily life of students in their local community; a reflection on the implementation of the project, highlighting positive and negative aspects; and a statistical analysis of the repercussion of the implementation of the project in the internal and external classifications of the students of the targeted classes. It is concluded that the presented implementation of the curriculum autonomy and flexibility project was an asset for teachers and students, providing a wide range of new learnings in accordance with the Student Profile on Leaving Compulsory Education. In terms of internal and external evaluations, students who usually have lower ratings have improved their ratings, with no significant differences observed in the ratings of students who already have good ratings

    A power comparison of generalized additive models and the spatial scan statistic in a case-control setting

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    <p>Abstract</p> <p>Background</p> <p>A common, important problem in spatial epidemiology is measuring and identifying variation in disease risk across a study region. In application of statistical methods, the problem has two parts. First, spatial variation in risk must be detected across the study region and, second, areas of increased or decreased risk must be correctly identified. The location of such areas may give clues to environmental sources of exposure and disease etiology. One statistical method applicable in spatial epidemiologic settings is a generalized additive model (GAM) which can be applied with a bivariate LOESS smoother to account for geographic location as a possible predictor of disease status. A natural hypothesis when applying this method is whether residential location of subjects is associated with the outcome, i.e. is the smoothing term necessary? Permutation tests are a reasonable hypothesis testing method and provide adequate power under a simple alternative hypothesis. These tests have yet to be compared to other spatial statistics.</p> <p>Results</p> <p>This research uses simulated point data generated under three alternative hypotheses to evaluate the properties of the permutation methods and compare them to the popular spatial scan statistic in a case-control setting. Case 1 was a single circular cluster centered in a circular study region. The spatial scan statistic had the highest power though the GAM method estimates did not fall far behind. Case 2 was a single point source located at the center of a circular cluster and Case 3 was a line source at the center of the horizontal axis of a square study region. Each had linearly decreasing logodds with distance from the point. The GAM methods outperformed the scan statistic in Cases 2 and 3. Comparing sensitivity, measured as the proportion of the exposure source correctly identified as high or low risk, the GAM methods outperformed the scan statistic in all three Cases.</p> <p>Conclusions</p> <p>The GAM permutation testing methods provide a regression-based alternative to the spatial scan statistic. Across all hypotheses examined in this research, the GAM methods had competing or greater power estimates and sensitivities exceeding that of the spatial scan statistic.</p

    A multilevel non-hierarchical study of birth weight and socioeconomic status

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    <p>Abstract</p> <p>Background</p> <p>It is unclear whether the socioeconomic status (SES) of the community of residence has a substantial association with infant birth weight. We used multilevel models to examine associations of birth weight with family- and community-level SES in the Cape Cod Family Health Study. Data were collected retrospectively on births to women between 1969 and 1983 living on Cape Cod, Massachusetts. The sample included siblings born in different residences with differing community-level SES.</p> <p>Methods</p> <p>We used cross-classified models to account for multiple levels of correlation in a non-hierarchical data structure. We accounted for clustering at family- and community-levels. Models included extensive individual- and family-level covariates. SES variables of interest were maternal education; paternal occupation; percent adults living in poverty; percent adults with a four year college degree; community mean family income; and percent adult unemployment.</p> <p>Results</p> <p>Residual correlation was detected at the family- but not the community-level. Substantial effects sizes were observed for family-level SES while smaller magnitudes were observed for community-level SES. Overall, higher SES corresponded to increased birth weight though neither family- nor community-level variables had significant associations with the outcome. In a model applied to a reduced sample that included a single child per family, enforcing a hierarchical data structure, paternal occupation was found to have a significant association with birth weight (p = 0.033). Larger effect sizes for community SES appeared in models applied to the full sample that contained limited covariates, such as those typically found on birth certificates.</p> <p>Conclusions</p> <p>Cross-classified models allowed us to include more than one child per family even when families moved between births. There was evidence of mild associations between family SES and birth weight. Stronger associations between paternal occupation and birth weight were observed in models applied to reduced samples with hierarchical data structures, illustrating consequences of excluding observations from the cross-classified analysis. Models with limited covariates showed associations of birth weight with community SES. In models adjusting for a complete set of individual- and family-level covariates, community SES was not as important.</p

    Retrospective Exposure Estimation and Predicted versus Observed Serum Perfluorooctanoic Acid Concentrations for Participants in the C8 Health Project

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    Background: People living or working in eastern Ohio and western West Virginia have been exposed to perfluorooctanoic acid (PFOA) released by DuPont Washington Works facilities

    A função tutorial na formação continuada docente

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    Mentoring is a topic of great relevance for the practice of the distance education as well as for the process of teaching and learning. Questions guiding this qualitative study related to the differences between mentoring and teaching and skills tutors must possess to ensure effective distance education. Our purpose was to identify tasks and skills teachers need to practice to serve as mentors. Our study highlighted some specific competencies and skills of great value to mentoring practice.A tutoria é um tema de grande relevância no trabalho da educação a distância e no processo de ensino e aprendizagem. Os questionamentos sobre as diferenças entre tutoria e a ação docente, além das competências que o Tutor deve ter sempre foram motivos de análise para a qualidade da educação a distância. Portanto no presente trabalho nosso objetivo é discutir as atribuições e competências necessárias para o exercício da função tutorial, mediante um estudo qualitativo e uma pesquisa-ação a partir do trabalho em desenvolvimento de educação a distância na formação continuada docente. Nossos estudos puderam contribuir com as reflexões sobre a temática e destacaram especificamente algumas competências e habilidades de grande valor para o trabalho tutorial

    The occurrence of the Monarch butterfly, Danaus plexippus L. in the Azores, with a brief review of its biology.

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    The Monarch butterfly, Danaus plexippus L. (Lepidoptera, Nymphalidae), has been an occasional visitor to the Azores. However, during the last two decades it has become a resident species in these islands and has adapted its behaviour to the geographic conditions of this new habitat, feeding on Gomphocarpus fruticosus (L.) Aiton fil. (Asclepiadaceae). The first confirmed breeding of this butterfly in the Azores (Faial island) is reported here and dates from the summer of 1994. However, previous sightings of only a very few adult individuals indicate that there was already a small resident population before 1994. Breeding was confirmed in three additional sites: on 3 June 1999, three adults of Monarch butterfly were observed laying eggs on G. fruticosus bushes near Ribeirinha and on 28 June 1999, several caterpillars were found in the same place. Larvae were also found at S. Roque (Pico island) and larvae and pupae at S. Carlos (Terceira island) in the summer of 1999. Monarch butterflies have been observed, occasionally, in Faial, Pico, Terceira, São Miguel, Santa Maria and Corvo during winter and spring, indicating the existence of a resident population all year round, but the vegetation used for wintering shelters has not yet been confirmed
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