Land cover classification of Lago Grande de Curuai floodplain (Amazon, Brazil) using multi-sensor and image fusion techniques

Given the limitations of different types of remote sensing images, automated land-cover classifications of the Amazon várzea may yield poor accuracy indexes. One way to improve accuracy is through the combination of images from different sensors, by either image fusion or multi-sensor classifications. Therefore, the objective of this study was to determine which classification method is more efficient in improving land cover classification accuracies for the Amazon várzea and similar wetland environments - (a) synthetically fused optical and SAR images or (b) multi-sensor classification of paired SAR and optical images. Land cover classifications based on images from a single sensor (Landsat TM or Radarsat-2) are compared with multi-sensor and image fusion classifications. Object-based image analyses (OBIA) and the J.48 data-mining algorithm were used for automated classification, and classification accuracies were assessed using the kappa index of agreement and the recently proposed allocation and quantity disagreement measures. Overall, optical-based classifications had better accuracy than SAR-based classifications. Once both datasets were combined using the multi-sensor approach, there was a 2% decrease in allocation disagreement, as the method was able to overcome part of the limitations present in both images. Accuracy decreased when image fusion methods were used, however. We therefore concluded that the multi-sensor classification method is more appropriate for classifying land cover in the Amazon várzea.

Evapotranspiração real diária em sub-bacias do Paracatu, utilizando produtos do sensor Modis

A evapotranspiração define a perda total de água do sistema solo-planta para a atmosfera. Nas áreas agrícolas, particularmente onde se pratica algum tipo de irrigação, a determinação da evapotranspiração, por via de sensoriamento remoto, vem ganhando cada vez mais importância, pois possibilita identificar a eficiência com que a água tem sido utilizada. Nesse contexto, este trabalho tem o objetivo de determinar a evapotranspiração real diária (ETr diária), com a utilização de produtos do sensor MODIS, nas sub-bacias do Ribeirão Entre Ribeiros e Rio Preto, que ficam entre os Estados de Goiás e Minas Gerais. O SEBAL (Surface Energy Balance Algorithm for Land) foi utilizado para a obtenção da ETr diária em quatro dias diferentes, no período de julho a outubro de 2007. Os resultados encontrados foram compatíveis com os citados em outras literaturas e a comparação entre a evapotranspiração, obtida pelo SEBAL, e a evapotranspiração da cultura (ETc) demonstraram que esse algoritmo pode ser utilizado como boa opção para determinar, com a utilização de produtos do sensor MODIS, a evapotranspiração diária nas condições das sub-bacias do ribeirão Entre Ribeiros e rio Preto.

Use efficiency of variable rate of nitrogen prescribed by optical sensor in corn

ABSTRACT The efficiency of nitrogen fertilizer in corn is usually low, negatively affecting plant nutrition, the economic return, and the environment. In this context, a variable rate of nitrogen, prescribed by crop sensors, has been proposed as an alternative to the uniform rate of nitrogen traditionally used by farmers. This study tested the hypothesis that variable rate of nitrogen, prescribed by optical sensor, increases the nitrogen use efficiency and grain yield as compared to uniform rate of nitrogen. The following treatments were evaluated: 0; 70; 140; and 210 kg ha-1 under uniform rate of nitrogen, and 140 kg ha -1 under variable rate of nitrogen. The nitrogen source was urea applied on the soil surface using a distributor equipped with the crop sensor. In this study, the grain yield ranged from 10.2 to 15.5 Mg ha-1, with linear response to nitrogen rates. The variable rate of nitrogen increased by 11.8 and 32.6% the nitrogen uptake and nitrogen use efficiency, respectively, compared to the uniform rate of nitrogen. However, no significant increase in grain yield was observed, indicating that the major benefit of the variable rate of nitrogen was reducing the risk of environmental impact of fertilizer.

Body image in Brazil: recent advances in the state of knowledge and methodological issues

OBJECTIVE To analyze Brazilian literature on body image and the theoretical and methodological advances that have been made. METHODS A detailed review was undertaken of the Brazilian literature on body image, selecting published articles, dissertations and theses from the SciELO, SCOPUS, LILACS and PubMed databases and the CAPES thesis database. Google Scholar was also used. There was no start date for the search, which used the following search terms: “body image” AND “Brazil” AND “scale(s)”; “body image” AND “Brazil” AND “questionnaire(s)”; “body image” AND “Brazil” AND “instrument(s)”; “body image” limited to Brazil and “body image”. RESULTS The majority of measures available were intended to be used in college students, with half of them evaluating satisfaction/dissatisfaction with the body. Females and adolescents of both sexes were the most studied population. There has been a significant increase in the number of available instruments. Nevertheless, numerous published studies have used non-validated instruments, with much confusion in the use of the appropriate terms (e.g., perception, dissatisfaction, distortion). CONCLUSIONS Much more is needed to understand body image within the Brazilian population, especially in terms of evaluating different age groups and diversifying the components/dimensions assessed. However, interest in this theme is increasing, and important steps have been taken in a short space of time.

Senses of body image in adolescents in elementary school

OBJECTIVE To comprehend the perception of body image in adolescence. METHODS A qualitative study was conducted with eight focus groups with 96 students of both sexes attending four public elementary school institutions in the city of Rio de Janeiro, Southeastern Brazil, in 2013. An interview guide with questions about the adolescents’ feelings in relation to: their bodies, standards of idealized beauty, practice of physical exercise and sociocultural influences on self-image. In the data analysis we sought to understand and interpret the meanings and contradictions of narratives, understanding the subjects’ context and reasons and the internal logic of the group. RESULTS Three thematic categories were identified. The influence of media on body image showed the difficulty of achieving the perfect body and is viewed with suspicion in face of standards of beauty broadcast; the importance of a healthy body was observed as standards of beauty and good looks were closely linked to good physical condition and result from having a healthy body; the relationship between the standard of beauty and prejudice, as people who are not considered attractive, having small physical imperfections, are discriminated against and can be rejected or even excluded from society. CONCLUSIONS The standard of perfect body propagated by media influences adolescents’ self-image and, consequently, self-esteem and is considered an unattainable goal, corresponding to a standard of beauty described as artificial and unreal. However, it causes great suffering and discrimination against those who do not feel they are attractive, which can lead to health problems resulting from low self-esteem.

Mapeamento do uso e cobertura da terra a partir da segmentação e classificação de imagens-fração solo, sombra e vegetação derivadas do modelo linear de mistura aplicado a dados do sensor TM/Landsat5, na região do reservatório de Tucuruí - PA

Técnicas de sensoriamento remoto são fundamentais para o monitoramento das mudanças de uso da terra, principalmente em áreas extensas como a Amazônia. O mapeamento de uso da terra, geralmente é realizado por métodos de classificação manual ou digital pixel a pixel, os quais consomem muito tempo. Este estudo aborda a aplicação do modelo linear de mistura em uma imagem Landsat-TM segmentada para o mapeamento das classes de uso da terra na região do reservatório de Tucuruí-PA para os anos de 1996 e 2001.

Exploring TM image texture and its relationships with biomass estimation in Rondônia, Brazilian Amazon

Many texture measures have been developed and used for improving land-cover classification accuracy, but rarely has research examined the role of textures in improving the performance of aboveground biomass estimations. The relationship between texture and biomass is poorly understood. This paper used Landsat Thematic Mapper (TM) data to explore relationships between TM image textures and aboveground biomass in Rondônia, Brazilian Amazon. Eight grey level co-occurrence matrix (GLCM) based texture measures (i.e., mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment, and correlation), associated with seven different window sizes (5x5, 7x7, 9x9, 11x11, 15x15, 19x19, and 25x25), and five TM bands (TM 2, 3, 4, 5, and 7) were analyzed. Pearson's correlation coefficient was used to analyze texture and biomass relationships. This research indicates that most textures are weakly correlated with successional vegetation biomass, but some textures are significantly correlated with mature forest biomass. In contrast, TM spectral signatures are significantly correlated with successional vegetation biomass, but weakly correlated with mature forest biomass. Our findings imply that textures may be critical in improving mature forest biomass estimation, but relatively less important for successional vegetation biomass estimation.

Detecção de cicatrizes de áreas queimadas baseada no modelo linear de mistura espectral e imagens índice de vegetação utilizando dados multitemporais do sensor MODIS/TERRA no estado do Mato Grosso, Amazônia brasileira

O objetivo desta pesquisa foi avaliar os dados do sensor MODIS para detectar e monitorar cicatrizes de áreas recém queimadas. Utilizamos imagens da reflectância de superfície do sensor MODIS: produto MOD09 (dia 5 de outubro) e produto MOD13A1 (meses de outubro e novembro). Foi avaliada também uma série temporal de um ano dos índices de vegetação (IV) EVI e NDVI (produto MOD13A1). Uma imagem do sensor ETM+ (dia 5 de outubro) foi utilizada como base para a delimitação dos polígonos amostrais e avaliação dos dados MODIS devido a sua melhor resolução espacial. A metodologia focou na aplicação do modelo linear de mistura espectral nas imagens reflectância para a geração das imagens fração sombra. Análises de regressão foram efetuadas para comparação entre o percentual de sombra derivado da imagem ETM+ e das imagens MODIS. As alterações multitemporais nas imagens IV foram avaliadas com base no teste de Tukey. Os resultados mostraram que a imagem fração sombra gerada a partir do produto MOD09 apresentou um R² = 0,66 (p < 0,01) em relação aos dados ETM+. Para as imagens do produto MOD13A1 não foram identificadas relações significativas. Os IV dentro dos mesmos polígonos apresentaram uma variação sazonal durante o ano. No entanto, não houve uma diminuição significativa dos valores destes índices nos meses onde foram observadas as cicatrizes de áreas recém queimadas. Portanto, o produto MOD09 mostrou-se mais eficiente que o produto MOD13A1 para a detecção de cicatrizes de áreas recém queimadas. A análise multitemporal dos IV sugeriu que não foi possível detectar este mesmo padrão na área de estudo.

Mapeamento da antiga cobertura vegetal de várzea do Baixo Amazonas a partir de imagens históricas (1975-1981) do Sensor MSS-Landsat

Este estudo apresenta um mapa da cobertura vegetal da planície de inundação do Rio Amazonas entre as cidades de Parintins (AM) e Almeirim (PA), com base em imagens Landsat-MSS adquiridas entre 1975 e 1981. O processamento digital dessas imagens envolveu a transformação para imagens-fração de vegetação, solo e água escura (sombra), seguido da aplicação de técnicas de segmentação e classificação por região. O mapa resultante da classificação foi organizado em quatro classes de cobertura do solo: floresta de várzea, vegetação não-florestal de várzea, solo exposto e água aberta. A precisão do mapa foi estimada a partir de dois tipos de informações coletadas em campo: 1) pontos de descrição: para validação das classes de cobertura não sujeitas a grandes alterações, como é o caso dos corpos d'água permanentes, e identificação de indicadores dos tipos de cobertura original presentes na paisagem na ocasião da obtenção das imagens (72 pontos); 2) entrevistas com moradores antigos para a recuperação da memória sobre a cobertura vegetal existente há 30 anos (44 questionários). Ao todo foram coletadas informações em 116 pontos distribuídos ao longo da área de estudo. Esses pontos foram utilizados para calcular o Índice Kappa de concordância entre os dados de campo e o mapa resultante da classificação automática, cujo valor (0,78) indica a boa qualidade do mapa de cobertura vegetal da várzea. Os resultados mostram que a região possuía uma cobertura florestal de várzea de aproximadamente 8.650 km2 no período de aquisição das imagens.

Eating behavior and body image among psychology students

OBJECTIVE: To characterize eating habits and possible risk factors associated with eating disorders among psychology students, a segment at risk for eating disorders. METHOD: This is a cross-sectional study. The questionnaires Bulimic Investigatory Test Edinburgh (BITE), Eating Attitudes Test (EAT-26), Body Shape Questionnaire (BSQ) and a variety that considers related issues were applied. Statistical Package for the Social Sciences (SPSS) 11.0 was utilized in analysis. The study population was composed of 175 female students, with a mean age of 21.2 (DP ± 3.6 years). RESULTS: A positive result was detected on the EAT-26 for 6.9% of the cases (CI95%: 3.6-11.7%). The prevalence of increased symptoms and intense gravity, according to the BITE questionnaire was 5% (CI95%: 2.4-9.5%) and 2.5% (CI95%: 0.7-6.3%), respectively. According to the findings, 26.29% of the students presented abnormal eating behavior. The population with moderate/severe BSQ scores presented dissatisfaction with corporal weight. CONCLUSION: The results indicate that attention must be given to eating behavior risks within this group. A differentiated gaze is justified with respect to these future professionals, whose practice is jeopardized in cases in which they are themselves the bearers of installed symptoms or precursory behavior.

Body image dissatisfaction and its relationship with physical activity and body mass index in Brazilian adolescents

Objective: To evaluate body image dissatisfaction and its relationship with physical activity and body mass index in a Brazilian sample of adolescents. Methods: A total of 275 adolescents (139 boys and 136 girls) between the ages of 14 and 18 years completed measures of body image dissatisfaction through the Contour Drawing Scale and current physical activity by the International Physical Activity Questionnaire. Weight and height were also measured for subsequent calculation of body mass index. Results: Boys and girls differed significantly regarding body image dissatisfaction, with girls reporting higher levels of dissatisfaction. Underweight and eutrophic boys preferred to be heavier, while those overweight preferred be thinner and, in contrast, girls desired to be thinner even when they are of normal weight. Conclusion: Body image dissatisfaction was strictly related to body mass index, but not to physical activity.

Marcapasso com sensor de contratilidade regulado pelas variações do sistema nervoso autônomo na miocardiopatia chagásica crônica

OBJETIVO: Analisar o desempenho da estimulação cardíaca artificial com marcapasso do tipo VVIR cujo sensor é regulado pelas variações do sistema nervoso autônomo em pacientes chagásicos com distúrbio no sistema de condução. MÉTODOS: Estudados 47 chagásicos, 28 do sexo masculino, com idades entre 24 e 68 anos, 36 tinham bloqueio atrioventricular (AV) total; 8, bloqueio AV de 2º grau 2; e 3 doença do nódulo sinusal, e encontravam-se, de acordo com a NYHA, em classe I (4), II (15), III (16) e IV (12). Após o implante de marcapasso do tipo VVIR os pacientes foram acompanhados durante 12 meses. A resposta de freqüência foi registrada em gravações de Holter de 24h e divididos em dois grupos de acordo com a FC em repouso - grupo 1: >65bpm e grupo 2: <=65bpm, para estudo comparativo, considerando: 1) FC em exercício no período de pós-implante; 2) PA em repouso após o implante e 3) avaliação dos grupos de eletrodos identificados como TIR-60-UP e outros eletrodos. RESULTADOS: O grupo 1 teve em exercício menor variação entre seus valores, do que o grupo 2, indicando que esse tipo de sistema de estimulação permite controlar individualmente cada paciente. Os valores de PA em repouso e em exercício não foram diferentes entre os grupos. O eletrodo do tipo TIR-60-UP, comportou-se como os demais eletrodos. CONCLUSÃO: O marcapasso do tipo VVIR cujo sensor é regulado pelas variações do SNA propicia o restabelecimento dos mecanismos fisiológicos em chagásicos, sendo que 74% deles tiveram melhora de uma ou duas classes funcionais da NYHA.

Evaluation of a linear spectral mixture model and vegetation indices (NDVI and EVI) in a study of schistosomiasis mansoni and Biomphalaria glabrata distribution in the state of Minas Gerais, Brazil

This paper analyses the associations between Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) on the prevalence of schistosomiasis and the presence of Biomphalaria glabrata in the state of Minas Gerais (MG), Brazil. Additionally, vegetation, soil and shade fraction images were created using a Linear Spectral Mixture Model (LSMM) from the blue, red and infrared channels of the Moderate Resolution Imaging Spectroradiometer spaceborne sensor and the relationship between these images and the prevalence of schistosomiasis and the presence of B. glabrata was analysed. First, we found a high correlation between the vegetation fraction image and EVI and second, a high correlation between soil fraction image and NDVI. The results also indicate that there was a positive correlation between prevalence and the vegetation fraction image (July 2002), a negative correlation between prevalence and the soil fraction image (July 2002) and a positive correlation between B. glabrata and the shade fraction image (July 2002). This paper demonstrates that the LSMM variables can be used as a substitute for the standard vegetation indices (EVI and NDVI) to determine and delimit risk areas for B. glabrata and schistosomiasis in MG, which can be used to improve the allocation of resources for disease control.

Perceived self-image in adolescent idiopathic scoliosis: an integrative review of the literature

Objective: To learn about the experiences of adolescents diagnosed with idiopathic scoliosis. Method: Integrative review of the literature published within a specified time frame. Results: For both sexes, the predominant clinical symptom of this condition appears to be the negative effect that the deformity exerts on perceived self-image. Quantitative studies used numerical scores to assess perceptions of body image but did not analyse emotional aspects. Patients treated surgically were found to have a better self-image than patients treated with a brace. Quality of life was improved by a reduction in the magnitude of the curve. Conclusion: Spinal deformity exerts a psychological effect on adolescent girls.