Multiple Geotechnological Tools Applied to Digital Mapping of Tropical Soils

ABSTRACT In recent years, geotechnologies as remote and proximal sensing and attributes derived from digital terrain elevation models indicated to be very useful for the description of soil variability. However, these information sources are rarely used together. Therefore, a methodology for assessing and specialize soil classes using the information obtained from remote/proximal sensing, GIS and technical knowledge has been applied and evaluated. Two areas of study, in the State of São Paulo, Brazil, totaling approximately 28.000 ha were used for this work. First, in an area (area 1), conventional pedological mapping was done and from the soil classes found patterns were obtained with the following information: a) spectral information (forms of features and absorption intensity of spectral curves with 350 wavelengths -2,500 nm) of soil samples collected at specific points in the area (according to each soil type); b) obtaining equations for determining chemical and physical properties of the soil from the relationship between the results obtained in the laboratory by the conventional method, the levels of chemical and physical attributes with the spectral data; c) supervised classification of Landsat TM 5 images, in order to detect changes in the size of the soil particles (soil texture); d) relationship between classes relief soils and attributes. Subsequently, the obtained patterns were applied in area 2 obtain pedological classification of soils, but in GIS (ArcGIS). Finally, we developed a conventional pedological mapping in area 2 to which was compared with a digital map, ie the one obtained only with pre certain standards. The proposed methodology had a 79 % accuracy in the first categorical level of Soil Classification System, 60 % accuracy in the second category level and became less useful in the categorical level 3 (37 % accuracy).

Digital soil mapping: strategy for data pre-processing

The region of greatest variability on soil maps is along the edge of their polygons, causing disagreement among pedologists about the appropriate description of soil classes at these locations. The objective of this work was to propose a strategy for data pre-processing applied to digital soil mapping (DSM). Soil polygons on a training map were shrunk by 100 and 160 m. This strategy prevented the use of covariates located near the edge of the soil classes for the Decision Tree (DT) models. Three DT models derived from eight predictive covariates, related to relief and organism factors sampled on the original polygons of a soil map and on polygons shrunk by 100 and 160 m were used to predict soil classes. The DT model derived from observations 160 m away from the edge of the polygons on the original map is less complex and has a better predictive performance.

Comparison between artificial neural networks and maximum likelihood classification in digital soil mapping

Soil surveys are the main source of spatial information on soils and have a range of different applications, mainly in agriculture. The continuity of this activity has however been severely compromised, mainly due to a lack of governmental funding. The purpose of this study was to evaluate the feasibility of two different classifiers (artificial neural networks and a maximum likelihood algorithm) in the prediction of soil classes in the northwest of the state of Rio de Janeiro. Terrain attributes such as elevation, slope, aspect, plan curvature and compound topographic index (CTI) and indices of clay minerals, iron oxide and Normalized Difference Vegetation Index (NDVI), derived from Landsat 7 ETM+ sensor imagery, were used as discriminating variables. The two classifiers were trained and validated for each soil class using 300 and 150 samples respectively, representing the characteristics of these classes in terms of the discriminating variables. According to the statistical tests, the accuracy of the classifier based on artificial neural networks (ANNs) was greater than of the classic Maximum Likelihood Classifier (MLC). Comparing the results with 126 points of reference showed that the resulting ANN map (73.81 %) was superior to the MLC map (57.94 %). The main errors when using the two classifiers were caused by: a) the geological heterogeneity of the area coupled with problems related to the geological map; b) the depth of lithic contact and/or rock exposure, and c) problems with the environmental correlation model used due to the polygenetic nature of the soils. This study confirms that the use of terrain attributes together with remote sensing data by an ANN approach can be a tool to facilitate soil mapping in Brazil, primarily due to the availability of low-cost remote sensing data and the ease by which terrain attributes can be obtained.

Comparison between detailed digital and conventional soil maps of an area with complex geology

Since different pedologists will draw different soil maps of a same area, it is important to compare the differences between mapping by specialists and mapping techniques, as for example currently intensively discussed Digital Soil Mapping. Four detailed soil maps (scale 1:10.000) of a 182-ha sugarcane farm in the county of Rafard, São Paulo State, Brazil, were compared. The area has a large variation of soil formation factors. The maps were drawn independently by four soil scientists and compared with a fifth map obtained by a digital soil mapping technique. All pedologists were given the same set of information. As many field expeditions and soil pits as required by each surveyor were provided to define the mapping units (MUs). For the Digital Soil Map (DSM), spectral data were extracted from Landsat 5 Thematic Mapper (TM) imagery as well as six terrain attributes from the topographic map of the area. These data were summarized by principal component analysis to generate the map designs of groups through Fuzzy K-means clustering. Field observations were made to identify the soils in the MUs and classify them according to the Brazilian Soil Classification System (BSCS). To compare the conventional and digital (DSM) soil maps, they were crossed pairwise to generate confusion matrices that were mapped. The categorical analysis at each classification level of the BSCS showed that the agreement between the maps decreased towards the lower levels of classification and the great influence of the surveyor on both the mapping and definition of MUs in the soil map. The average correspondence between the conventional and DSM maps was similar. Therefore, the method used to obtain the DSM yielded similar results to those obtained by the conventional technique, while providing additional information about the landscape of each soil, useful for applications in future surveys of similar areas.

Avaliação do grau de satisfação entre os usuários de amplificação de tecnologia analógica e digital

OBJETIVO: objetivo desta pesquisa foi investigar o grau de satisfação entre os usuários de Aparelho de Amplificação Sonora (AAS) de tecnologia analógica e digital. FORMA DE ESTUDO: clínico com coorte transversal. MATERIAL E MÉTODO: A amostra foi constituída de 40 usuários de AAS unilateral, sendo 20 de tecnologia analógica (Grupo I) e 20 de tecnologia digital (Grupo II). Os indivíduos são portadores de perda auditiva neurossensorial, de configuração plana, de grau leve a moderado, com idade entre 40 e 95 anos. O instrumento de avaliação utilizado foi o International Outcome Inventory for Hearing Aids (IOI-HA - Versão em Português) proposto por Cox et al. (2002). RESULTADOS: Os resultados mostraram que os usuários do Grupo II utilizam o AAS por mais tempo diariamente e também apresentam um grau de dificuldade menor em determinadas situações com o uso da amplificação, comparado aos usuários do Grupo I. Os usuários do Grupo II relatam que sua perda auditiva não afeta em nada sua relação com terceiros. CONCLUSÃO: Apesar de os resultados revelarem que os usuários do Grupo I apresentam um handicap auditivo mais acentuado comparado aos usuários do Grupo II, o grau de satisfação com relação à amplificação não apresenta diferença significativa entre os dois grupos.

Internet e participação: o caso do orçamento participativo digital de Belo Horizonte

Este artigo investiga as representações sociais que emergem da participação pública mediada pelo uso de Tecnologias de Informação e Comunicação (TIC). A prefeitura de Belo Horizonte, em 2006, usou pela primeira vez a TIC no Orçamento Participativo Digital (OP Digital). Foi uma escolha da população das obras prioritárias para o biênio seguinte. O OP Digital foi repetido em 2008 e 2011, mas com participação inferior à obtida na primeira edição. Realizamos este trabalho para compreender o uso da internet pelo cidadão na tomada de decisão pública e para explicar a diminuição da sua participação. Os procedimentos metodológicos estão ancorados na teoria das representações sociais e na análise crítica do discurso de 101 textos - da imprensa e de órgãos públicos ou representantes do governo. Os resultados nos indicam que não está sendo explorado o potencial de interação e construção coletiva da internet, ancorando a nova prática em uma votação, dessa forma, trivializando-a. Essa pode ser uma das razões para o abandono da participação.

Sentidos e significados da participação democrática através da Internet: uma análise da experiência do Orçamento Participativo Digital

Este trabalho analisa três edições (2006, 2008 e 2011) do Orçamento Participativo Digital (OPD) de Belo Horizonte (MG). Objetiva deslindar os sentidos e significados da participação democrática mediada pela internet nessa experiência. Utiliza-se como método o estudo de caso único, de natureza qualitativa. Os dados foram coletados por meio de observação direta nos sítios do OPD e análise documental. Durante a fase de observação direta foram coletadas mensagens e manifestações dos cidadãos que estavam participando do processo. Tais dados foram tratados com o software Atlas TI 6.0®. Conclui-se que tanto o sentido quanto o significado democrático dessa experiência de participação mediadas pela internet são modificados ao longo das edições, indo de grandes impulsos de esperança democrática até a descrença nessa modalidade de participação digital.

Digital disease detection and participatory surveillance: overview and perspectives for Brazil

ABSTRACT This study aimed to describe the digital disease detection and participatory surveillance in different countries. The systems or platforms consolidated in the scientific field were analyzed by describing the strategy, type of data source, main objectives, and manner of interaction with users. Eleven systems or platforms, developed from 1996 to 2016, were analyzed. There was a higher frequency of data mining on the web and active crowdsourcing as well as a trend in the use of mobile applications. It is important to provoke debate in the academia and health services for the evolution of methods and insights into participatory surveillance in the digital age.

Identification and characterization of deforestation hot spots in Venezuela using MODIS satellite images

Land cover changes over time as a result of human activity. Nowadays deforestation may be considered one of the main environmental problems. The objective of this study was to identify and characterize changes to forest cover in Venezuela between 2005-2010. Two maps of deforestation hot spots were generated on the basis of MODIS data, one using digital techniques and the other by means of direct visual interpretation by experts. These maps were validated against Landsat ETM+ images. The accuracy of the map obtained digitally was estimated by means of a confusion matrix. The overall accuracy of the maps obtained digitally was 92.5%. Expert opinions regarding the hot spots permitted the causes of deforestation to be identified. The main processes of deforestation were concentrated to the north of the Orinoco River, where 8.63% of the country's forests are located. In this region, some places registered an average annual forest change rate of between 0.72% and 2.95%, above the forest change rate for the country as a whole (0.61%). The main causes of deforestation for the period evaluated were agricultural and livestock activities (47.9%), particularly family subsistence farming and extensive farming which were carried out in 94% of the identified areas.

Nicolas Sanson and his Map: The Course of the Amazon River

One of the first scientific maps of the Amazon region, The Course of the Amazon River (Le Cours de La Rivière des Amazones), was constructed by Nicolas Sanson, a French cartographer of the seventeenth century, and served as the prototype for many others. The evaluation of this chart, until now, has been that it is a very defective map, a sketch based on a historical account, according to the opinion of La Condamine. Thus, the aim of the present work was to prove that the map of the Amazon River traced by Nicolas Sanson is a scientific work, a map that presents precise geographic coordinates considering its time, shows a well-determined prime meridian, and also employs a creative methodology to deduce longitudes from latitudes and distances that had been covered. To show such characteristics, an analysis of the accuracy of the map was made by comparing its latitudes and longitudes with those of a current map. We determined the prime meridian of this map and analyzed the methodology used for the calculation of longitudes. The conclusion is that it is actually a good map for the time, particularly considering the technology and the limited information that Sanson had at his disposal. This proves that the negative assertion of La Condamine is unfounded.

Uso de digital em idosos admitidos em unidade de geriatria de um hospital geral

OBJETVO: Detectar a freqüência da prescrição do digital, assim como as suas indicações, em idosos admitidos em unidade de geriatria de um hospital geral. MÉTODOS: Foram investigados, consecutivamente, 130 pacientes não selecionados, de ambos os sexos (100 mulheres e 30 homens), com idades > ou = 65 (média 80±9) anos. Os pacientes foram avaliados através de exame clínico completo, rotina básica de sangue, radiografia simples de tórax, eletrocardiograma e ecocardiograma Doppler. Baseados na avaliação clínica e exames complementares, o uso do digital foi considerado adequado, questionável ou inadequado. RESULTADOS: Estavam em uso de digital 27,6% dos pacientes. A indicação foi considerada adequada em 36,1%, questionável em 11,1% e inadequada em 52,7%. CONCLUSÃO: Uma alta prevalência de prescrição do digital foi detectada nos idosos admitidos, sendo que a maior parte a adotava por razões consideradas inadequadas ou questionáveis. Devido ao risco aumentado de intoxicação digitálica nessa faixa etária, a droga deveria ser prescrita sob indicações mais criteriosas.

Detection of incipient left ventricular hypertrophy in mild to moderate arterial hypertension with normal electrocardiogram and echocardiogram: a new use for signal-averaged electrocardiography

OBJECTIVE: To assess signal-averaged electrocardiogram (SAECG) for diagnosing incipient left ventricular hypertrophy (LVH). METHODS: A study with 115 individuals was carried out. The individuals were divided as follows: GI - 38 healthy individuals; GII - 47 individuals with mild to moderate hypertension and normal findings on echocardiogram and ECG; and GIII - 30 individuals with hypertension and documented LVH. The magnitude vector of the SAECG was analyzed with the high-pass cutoff frequency of 40 Hz through the bidirectional four-pole Butterworth high-pass digital filter. The mean quadratic root of the total QRS voltage (RMST) and the two-dimensional integral of the QRS area of the spectro-temporal map were analyzed between 0 and 30 Hz for the frequency domain (Int FD), and between 40 and 250 Hz for the time domain (Int TD). The electrocardiographic criterion for LVH was based on the Cornell Product. Left ventricular mass was calculated with the Devereux formula. RESULTS: All parameters analyzed increased from GI to GIII, except for Int FD (GII vs GIII) and RMST log (GII vs GIII). Int TD showed greater accuracy for detecting LVH with an appropriate cutoff > 8 (sensitivity of 55%, specificity of 81%). Positive values (> 8) were found in 56.5% of the G II patients and in 18.4% of the GI patients (p< 0.0005). CONCLUSION: SAECG can be used in the early diagnosis of LVH in hypertensive patients with normal ECG and echocardiogram.

Validade de um monitor digital de pulso para mensuração de pressão arterial em comparação com um esfigmomanômetro de mercúrio

FUNDAMENTO: Medidas válidas da pressão arterial, em situações clínicas e na comunidade, são essenciais para a monitoração dessa variável em nível populacional. OBJETIVO: Avaliar a validade de um monitor digital de pulso para mensuração da pressão arterial em adolescentes, em comparação com um esfigmomanômetro de mercúrio. MÉTODOS: Um estudo de validação foi realizado na cidade de Pelotas, região sul do Brasil. A pressão arterial foi medida duas vezes, utilizando-se dois esfigmomanômetros diferentes: um aparelho digital de pulso OMRON e um aparelho de mesa BD de mercúrio. Metade da amostra foi medida primeiro através do manômetro digital e depois pelo de mercúrio, enquanto a outra metade foi avaliada na ordem inversa. A concordância entre as duas medidas foi avaliada através do método de Bland & Altman. RESULTADOS: 120 adolescentes com idade entre 14 e 15 anos foram incluídos no estudo (50% de cada sexo). A pressão sistólica média entre os meninos foi de 113,7 mmHg (DP 14,2) usando o manômetro de mercúrio e 115,5 mmHg (DP 15,2) usando o aparelho digital. Os valores equivalentes para a pressão diastólica foram 61,5 mmHg (DP 9,9) e 69,6 mmHg (10,2), respectivamente. Entre as meninas, a pressão sistólica média foi de 104,7 mmHg (DP 10,1) usando o manômetro de mercúrio e 102,4 mmHg (DP 11.9) usando o aparelho digital. Os valores equivalentes para a pressão diastólica foram 60,0 mmHg (DP 10,4) e 65,7 mmHg (DP 7,7), respectivamente. CONCLUSÕES: O manômetro digital apresentou alta concordância com o manômetro de mercúrio para medir a pressão arterial sistólica. A concordância foi menor para a pressão arterial diastólica. O uso de equações de correção pode ser uma alternativa para estudos utilizando esse monitor digital de pulso em adolescentes.