Evaluation of statistical and geostatistical models of digital soil properties mapping in tropical mountain regions

Soil properties have an enormous impact on economic and environmental aspects of agricultural production. Quantitative relationships between soil properties and the factors that influence their variability are the basis of digital soil mapping. The predictive models of soil properties evaluated in this work are statistical (multiple linear regression-MLR) and geostatistical (ordinary kriging and co-kriging). The study was conducted in the municipality of Bom Jardim, RJ, using a soil database with 208 sampling points. Predictive models were evaluated for sand, silt and clay fractions, pH in water and organic carbon at six depths according to the specifications of the consortium of digital soil mapping at the global level (GlobalSoilMap). Continuous covariates and categorical predictors were used and their contributions to the model assessed. Only the environmental covariates elevation, aspect, stream power index (SPI), soil wetness index (SWI), normalized difference vegetation index (NDVI), and b3/b2 band ratio were significantly correlated with soil properties. The predictive models had a mean coefficient of determination of 0.21. Best results were obtained with the geostatistical predictive models, where the highest coefficient of determination 0.43 was associated with sand properties between 60 to 100 cm deep. The use of a sparse data set of soil properties for digital mapping can explain only part of the spatial variation of these properties. The results may be related to the sampling density and the quantity and quality of the environmental covariates and predictive models used.

Optimization of preservation conditions of As (III) bioreporter bacteria.

Long-term preservation of bioreporter bacteria is essential for the functioning of cell-based detection devices, particularly when field application, e.g., in developing countries, is intended. We varied the culture conditions (i.e., the NaCl content of the medium), storage protection media, and preservation methods (vacuum drying vs. encapsulation gels remaining hydrated) in order to achieve optimal preservation of the activity of As (III) bioreporter bacteria during up to 12 weeks of storage at 4 degrees C. The presence of 2% sodium chloride during the cultivation improved the response intensity of some bioreporters upon reconstitution, particularly of those that had been dried and stored in the presence of sucrose or trehalose and 10% gelatin. The most satisfying, stable response to arsenite after 12 weeks storage was obtained with cells that had been dried in the presence of 34% trehalose and 1.5% polyvinylpyrrolidone. Amendments of peptone, meat extract, sodium ascorbate, and sodium glutamate preserved the bioreporter activity only for the first 2 weeks, but not during long-term storage. Only short-term stability was also achieved when bioreporter bacteria were encapsulated in gels remaining hydrated during storage.

Compara����o do uso de modelos digitais de eleva����o em mapeamento digital de solos em Dois Irm��os, RS, Brasil

Os modelos digitais de eleva����o (MDEs) s��o fontes fundamentais para correlacionar a ocorr��ncia e distribui����o de solos com a paisagem pelo mapeamento digital de solos (MDS). A influ��ncia dos tipos e das resolu����es dos MDEs na capacidade de predi����o dos modelos preditores de classes de solo ainda �� pouco estudada. Neste estudo, foram avaliados e comparados os efeitos de diferentes MDEs na predi����o de ocorr��ncia de unidades de mapeamento de solo (UM). Foram correlacionados 12 atributos do terreno derivados de diferentes MDEs com a ocorr��ncia de UM. Os MDEs utilizados foram os oriundos dos projetos SRTM v4.1, ASTER GDEM v2, TOPODATA e Brasil em Relevo, e os MDEs gerados a partir de curvas de n��vel na escala de 1:50.000, com resolu����es de 30 e 90 m. Os modelos preditores foram treinados por ��rvore de decis��o (Simple Cart) com dados amostrados em 4.280 pontos aleat��rios contendo informa����es dos solos extra��dos de um mapa convencional de solos na escala 1:20.000 e 12 atributos do terreno derivados de seis MDEs com tamanhos de pixel de 30 e 90 m. A valida����o dos modelos preditores de UM foi realizada com a totalidade dos dados da ��rea. Os atributos do terreno que melhor explicaram a ocorr��ncia das UM foram eleva����o, declividade, comprimento de fluxo e orienta����o das vertentes. Os MDEs com tamanho de pixel de 30 m geraram correla����es solo-paisagem menos acuradas. Os modelos preditores mais acurados e com maior n��mero de UM estimadas foram os gerados a partir dos MDEs com resolu����o espacial de 90 m (SRTM v4.1 e CN90), sendo esses os MDEs mais indicados para o MDS, quando predominarem relevos plano e suave ondulado.

Mapeamento digital de atributos: granulometria e mat��ria org��nica do solo utilizando espectroscopia de de reflect��ncia difusa

A espectroscopia de reflect��ncia difusa (ERD) pode ser utilizada como alternativa para quantifica����o de atributos como granulometria e mat��ria org��nica do solo (MOS). Essa t��cnica pode ser op����o para quantificar esses atributos em grande volume de amostras de solos, visto ser r��pida, com menor custo e sem a gera����o de res��duos qu��micos. O objetivo deste estudo foi desenvolver modelos usando an��lise de regress��o linear m��ltipla para predizer o teor de argila, areia, silte e MOS, utilizando dados de ERD em uma ��rea de relevo e geologia complexa localizada na regi��o central do Rio Grande do Sul. No estudo, foram utilizadas 303 amostras coletadas na profundidade de 0,00-0,20 m para determinar os teores de argila, areia, silte e MOS por meio da an��lise laboratorial e de reflect��ncia espectral. O desempenho dos modelos de predi����o apresentaram bons resultados, com capacidade de explica����o da vari��ncia de 77 e 72 % para areia e argila, respectivamente. Mesmo com a complexidade geol��gica e pedol��gica, os resultados evidenciaram que a t��cnica �� promissora, sendo poss��vel a aplica����o dessa t��cnica para predi����o da granulometria e teor de MOS.

COMPARA����O DE ESQUEMAS DE AMOSTRAGEM PARA TREINAMENTO DE MODELOS PREDITORES NO MAPEAMENTO DIGITAL DE CLASSES DE SOLOS

Os modelos preditores usados no mapeamento digital de solos (MDS) precisam ser treinados com dados que captem ao máximo a variação dos atributos do terreno e dos solos, a fim de gerar correlações adequadas entre as variáveis ambientais e a ocorrência dos solos. Para avaliar a acurácia desses modelos, tem sido constatado o uso de diferentes métodos de avaliação da acurácia no MDS. Os objetivos deste estudo foram comparar o uso de três esquemas de amostragem para treinar algoritmo de árvore de classificação (CART) e avaliar a capacidade de predição dos modelos gerados por meio de quatro métodos. Foram utilizados os esquemas de amostragem: aleatório simples; proporcional à área de cada unidade de mapeamento de solos (UM); e estratificado pelo número de UM. Os métodos de avaliação testados foram: aparente, divisão percentual, validação cruzada com 10 subconjuntos e reamostragem com sete conjuntos de dados independentes. As acurácias dos modelos estimadas pelos métodos foram comparadas com as acurácias mensuradas obtidas pela comparação dos mapas gerados, a partir de cada esquema de amostragem, com o mapa convencional de solos na escala 1:50.000. Os esquemas de amostragem influenciaram na quantidade de UMs preditas e na acurácia dos modelos e dos mapas gerados. Os esquemas de amostragem proporcional e estratificada resultaram mapas digitais menos acurados, e a acurácia dos modelos variou conforme o método de avaliação empregado. A amostragem aleatória resultou no mapa digital mais acurado e apresentou valores da acurácia semelhantes para todos os métodos de avaliação testados.

Squamous cell carcinoma of the larynx with subglottic extension: is larynx preservation possible?. Plattenepithelkarzinom des Larynx mit subglottischer Ausdehnung: ist ein Larynxerhalt m��glich ?

PURPOSE: Squamous cell carcinoma of larynx with subglottic extension (sSCC) is a rare location described to carry a poor prognosis. The aim of this study was to analyze outcomes and feasibility of larynx preservation in sSCC patients. PATIENTS AND METHODS: Between 1996 and 2012, 197��patients with sSCC were treated at our institution and included in the analysis. Stage III-IV tumors accounted for 76 %. Patients received surgery (62 %), radiotherapy (RT) (18 %), or induction chemotherapy (CT) (20 %) as front-line therapy. RESULTS: The 5-year actuarial overall survival (OS), locoregional control (LRC), and distant control rate were 59 % (95 % CI 51-68), 83 % (95 % CI 77-89), and 88 % (95 % CI 83-93), respectively, with a median follow-up of 54.4 months. There was no difference in OS and LRC according to front-line treatments or between primary subglottic cancer and glottosupraglottic cancers with subglottic extension. In the multivariate analysis, age > 60 years and positive N stage were the only predictors for OS (HR 2, 95 % CI 1.2-3.6; HR1.9, 95 % CI 1-3.5, respectively). A lower LRC was observed for T3 patients receiving a larynx preservation protocol as compared with those receiving a front-line surgery (HR 14.1, 95 % CI 2.5-136.7; p = 0.02); however, no difference of ultimate LRC was observed according to the first therapy when including T3 patients who underwent salvage laryngectomy (p = 0.6). In patients receiving a larynx preservation protocol, the 5-year larynx-preservation rate was 55 % (95 % CI 43-68), with 36 % in T3 patients. The 5-year larynx preservation rate was 81 % (95 % CI 65-96) and 35 % (95 % CI 20-51) for patients who received RT or induction CT as a front-line treatment, respectively. CONCLUSION: Outcomes of sSCC are comparable with other laryngeal cancers when managed with modern therapeutic options. Larynx-preservation protocols could be a suitable option in T1-T2 (RT or chemo-RT) and selected T3 sSCC patients (induction CT).

Spatial analysis of erythrocyte membrane fluctuations by digital holographic microscopy.

Red blood cell (RBC) membrane fluctuations provide important insights into cell states. We present a spatial analysis of red blood cell membrane fluctuations by using digital holographic microscopy (DHM). This interferometric and dye-free technique, possessing nanometric axial and microsecond temporal sensitivities enables to measure cell membrane fluctuations (CMF) on the whole cell surface. DHM acquisition is combined with a model which allows extracting the membrane fluctuation amplitude, while taking into account cell membrane topology. Uneven distribution of CMF amplitudes over the RBC surface is observed, showing maximal values in a ring corresponding to the highest points on the RBC torus as well as in some scattered areas in the inner region of the RBC. CMF amplitudes of 35.9+/-8.9 nm and 4.7+/-0.5 nm (averaged over the cell surface) were determined for normal and ethanol-fixed RBCs, respectively.

SELE����O DE DENSIDADE DE AMOSTRAGEM COM BASE EM DADOS DE ��REAS J�� MAPEADAS PARA TREINAMENTO DE MODELOS DE ��RVORE DE DECIS��O NO MAPEAMENTO DIGITAL DE SOLOS

Para estudar t��cnicas de amostragem, ��teis ao mapeamento digital de solos (MDS), objetivou-se avaliar o efeito da varia����o da densidade de pontos amostrais com base em dados de ��reas j�� mapeadas por m��todos tradicionais na acur��cia dos modelos de ��rvores de decis��o (AD) para a gera����o de mapas de solos por MDS. Em duas bacias hidrogr��ficas no noroeste do Rio Grande do Sul, usou-se, como refer��ncia, antigos mapas convencionais de solos na escala 1:50.000. A partir do modelo digital de eleva����o do terreno e da rede hidrogr��fica, foram gerados mapas das vari��veis preditoras: eleva����o, declividade, curvatura, comprimento de fluxo, ac��mulo de fluxo, ��ndice de umidade topogr��fica e dist��ncia euclideana de rios. A escolha dos locais dos pontos amostrais foi aleat��ria e testaram-se densidades amostrais que variaram de 0,1 a 4 pontos/ha. O treinamento dos modelos foi realizado no software Weka, gerando-se modelos preditores usando diferentes tamanhos do n�� final da AD para obter AD com tamanhos distintos. Quando n��o se controlou o tamanho das AD, o aumento da densidade de amostragem resultou no aumento da concord��ncia com os mapas b��sicos de refer��ncias e no aumento do n��mero de unidades de mapeamento preditas. Nas AD com tamanho controlado, o aumento da densidade de amostragem n��o influenciou a concord��ncia com os mapas de refer��ncia e interferiu muito pouco no n��mero de unidades de mapeamento preditas.

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 S��o 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).

Field Evaluation of Timber Preservation Treatments for Highway Applications Final Report, December 2007

Timber material repair and replacement cost for timber bridges is a considerable expense to highway agencies in Iowa, especially to county road departments. To address these needs, the objectives of this investigation was to study the field effectiveness of various treatment alternatives used on Iowa roadway projects and to determine if the current specifications and testing are adequate for providing proper wood preservation. To satisfy the research needs, the project scope involved a literature review, identification of metrics, questionnaire survey of Iowa counties, onsite inspections, and a review of current specifications and testing procedures. Based on the preservative information obtained, the following general conclusions were made: Copper naphthenate is recommended as the plant-applied preservative treatment for timber bridges. Best Management Practices should be followed to ensure quality treatment of timber materials. Bridge maintenance programs need to be developed and implemented. The Iowa Department of Transportation specifications for preservative treatment are the regulating specification for bridges constructed with state or federal funding in Iowa and are also recommended for all other bridges.

Digital holographic microscopy: a noninvasive contrast imaging technique allowing quantitative visualization of living cells with subwavelength axial accuracy.

We have developed a digital holographic microscope (DHM), in a transmission mode, especially dedicated to the quantitative visualization of phase objects such as living cells. The method is based on an original numerical algorithm presented in detail elsewhere [Cuche et al., Appl. Opt. 38, 6994 (1999)]. DHM images of living cells in culture are shown for what is to our knowledge the first time. They represent the distribution of the optical path length over the cell, which has been measured with subwavelength accuracy. These DHM images are compared with those obtained by use of the widely used phase contrast and Nomarski differential interference contrast techniques.

Desafios do modelo brasileiro de inclus��o digital pela escola

Este artigo discute os rumos da pol��tica p��blica de inclus��o digital nas escolas com base nos resultados da pesquisa de avalia����o de impacto e de processo do Projeto UCA-Total (Um Computador por Aluno) realizada em cinco munic��pios onde foi implementado no decorrer de 2010 e 2011. A avalia����o de impacto, de car��ter longitudinal, foi feita atrav��s de um survey domiciliar aplicado em duas ondas. A pesquisa de processo associou diversas metodologias qualitativas, como grupos focais, entrevistas e visitas a campo. Limita-se aqui aos resultados derivados da pesquisa de painel, que revelam o baixo n��vel de aproveitamento do Projeto e um padr��o de funcionamento bastante divergente em raz��o de vantagens e debilidades locais. Seu enorme potencial n��o foi at�� hoje completamente aproveitado.

La Recerca en obert al Dip��sit Digital de la UB

Comunicaci�� presentada a: II Setmana Internacional de l'Acc��s Obert a la Universitat de Barcelona. Universitat de Barcelona, del 18 al 22 d'octubre de 2010

Captant la recerca: interconnexi�� entre el repositori institucional (Dip��sit Digital UB) i el Gestor de RECerca (GREC)

Comunicaci�� presentada al 2n Espai CBUC d'intercanvi de coneixements i experi��ncies, Barcelona 3-5 de marzo de 2010