É apresentada uma nova abordagem na técnica e na avaliação de área de florestas nativas, exóticas e uso do solo do Nordeste do Estado do Rio Grande do Sul, em particular no entorno da escarpa que divide os Campos de Cima da Serra e a Planície Costeira, caracterizada por apresentar espécies de Pinus elliotti Engelm var elliottiii e Pinus taeda L., Eucalyptus sp. e Araucaria angustifólia (Bert.) O. Ktze. e áreas de campo nativo. Nas últimas décadas tem se verificado avanço das florestas exóticas, principalmente de florestas de pinus, sobre as áreas de campo e florestas nativas, surgindo como uma das maiores fontes de exploração econômica da região. Parcialmente em razão disto, as florestas de araucária distribuem-se de forma pouco homogênea, em decorrência de décadas de desmatamento. As técnicas de classificação em Sensoriamento Remoto, usando imagens de Landsat, mostraram que é possível separar tipos diferentes de vegetação, e no exemplo das florestas na região estudada, tanto nativas como exóticas. As limitações em definições espacial e espectral até meados da década de 1990 motivaram o desenvolvimento de uma nova geração de satélites e sensores, incluindo o sensor ASTER a bordo do satélite Terra. Este sensor apresenta 14 bandas espectrais com diferentes resoluções espaciais, sendo usado nesta pesquisa suas 9 bandas correspondentes ao espectro de radiância refletida. O foco central deste trabalho está na utilização de sensoriamento remoto e geoprocessamento para determinação de áreas de vegetação e uso do solo no extremo leste dos Campos de Cima da Serra, através de imagens orbitais do sensor ASTER. Utilizando métodos de classificação supervisionada foi possível caracterizar a área, separar as espécies vegetais entre si, além de quantificá-las O grupo das 9 bandas foram distribuídas em três grupos: com 3 bandas de resolução espacial de 15 metros no visível e infravermelho próximo (VNIR); com 6 bandas com resolução espacial de 30 metros no infravermelho médio (SWIR); e com 9 bandas com resolução espacial de 30 metros cobrindo toda a faixa de resolução espectral do espectro de radiância refletida do sensor ASTER (VNIR+SWIR). A metodologia incluiu processamento de imagem e classificação com o algoritmo de máxima verossimilhança gaussiana. Os resultados são: 1) é possível identificar tipos diferentes de manejo e idade nas florestas de Pinus elliottii (jovens, adulto, velho e manejado diferenciado); 2) a exatidão geral foi de 90,89% no subsistema VNIR, e o índice do Kappa foi de 0,81 em ambos subsistemas VNIR e (VNIR+SWIR); 3) a classificação apresentando o mapa do uso do solo mostra que, de forma geral, os dados de VNIR têm os melhores resultados, incluindo o detalhamento para pequenas áreas da superfície terrestre. O grupo (VNIR+SWIR) têm potencial superior para a determinação das classes araucária , eucalipto e pinus com manejo / pinus adulto , enquanto que o grupo SWIR não apresenta não vence em nenhuma classe; 4) com relação aos dados de exatidão geral resultantes do subsistema VNIR, a área estimada de pinus é 22,28% da área estudada (cena de 1543,63 quilômetros quadrados totais), e de araucária é 10,10%, revelando que aquela espécie exótica está mudando rapidamente a paisagem da região. Na comparação destes resultados com outros estudos na região pesquisada, verifica-se que a utilização de dados ASTER implica em um aumento na acurácia da classificação de vegetação em geral e que este sensor é altamente apropriado para estudos ambientais, devido a suas excelentes características espaciais e espectrais.

Submitted by João Arthur Martins (joao.arthur@ufpe.br) on 2015-03-03T19:36:52Z No. of bitstreams: 2 dissertacao_final...pdf: 9675674 bytes, checksum: 8632ccf65588edcc72a68d26b24f3e28 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-03T19:36:52Z (GMT). No. of bitstreams: 2 dissertacao_final...pdf: 9675674 bytes, checksum: 8632ccf65588edcc72a68d26b24f3e28 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012-08-21 / Este trabalho trata de uma investigação dos métodos de detecção de borda de reservatório usando imagens de Sensoriamento Remoto em um estudo de caso das bordas do reservatório de Sobradinho, Bahia, Brasil. Os testes realizados incluíram imagens TM LANDSAT-5, MDE-SRTM, borda do SRTM-SWBD e ASTER-GDEM-VNIR, e no processamento foram testados operadores de abertura e fechamento de Morfologia Matemática do MDESRTM e segmentação da banda 4 do TM LANDSAT-5 (borda B4). A segmentação da banda 4 do TM foi o método que melhor representou a borda do reservatório de Sobradinho, em relação aos testes de borda feitos com os operadores de Morfologia Matemática aplicadas ao MDE-SRTM, fatiamento altimétrico ASTER-GDEM-VNIR e MDE SRTM, e a borda SRTM-SWBD da NASA/NGA. Os dados ASTER-GDEM-VNIR formam um mosaico descontínuo no tempo implicando em distintos níveis de água de Sobradinho (distinta bordas) que não se completam. Outro problema observado nos dados ASTERGDEM- VNIR disponíveis e grátis para o público, é o não conhecimento da data das imagens. Com relação à análise dos resultados do processamento das imagens para detecção de borda os operadores de Morfologia Matemática de dilatação e erosão geram pixels maiores que 30 m degradando a resolução espacial do TM. Os dados SRTM-SWBD da NASA divergem em planimetria da borda MDE-SRTM e da borda B4. Foram elaborados perfis altimétricos entre as bordas MDE-SRTM e radiométricos na B4 e constatou-se: baixa penetração do imageamento do MDE-SRTM nas reentrâncias das bordas do reservatório, enquanto as maiores elevações do terreno são mais destacadas do que os terrenos de baixa declividade; a não observação das datas das imagens utilizadas na cobertura de solo bem como a ignorância à dinâmica da superfície da borda do reservatório, utilizada na geração dos dados são as principais causas das discrepâncias entre a borda SRTM-SWBD (SWB) e a segmentação da banda 4.

Submitted by Romulus Lima (romulus.lima@ufpe.br) on 2015-03-04T18:22:54Z No. of bitstreams: 2 DISSERTAÇÃO Marcondes Marroquim Santiago.pdf: 3489125 bytes, checksum: 72f11a6dd5bdafe0a78d84b7bad260ea (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-04T18:22:54Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Marcondes Marroquim Santiago.pdf: 3489125 bytes, checksum: 72f11a6dd5bdafe0a78d84b7bad260ea (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / CAPES / Modelo Digital de Elevação (MDE) do ASTER-2 é um modelo obtido a partir de imagens estereoscópicas orbitais que recobre uma área de extensão global, entre as latitudes 83ºN e 83ºS. O United States Geological Survey (UGSS) e o Earth Remote Sensing Data Analysis Center (ERSDAC) desenvolveram estudos sobre a precisão desse modelo, com base no Erro Médio (EM) e no Desvio Padrão ( ) deste erro, chegando a valores diferentes. A declividade é um produto derivado do MDE, obtida por operações de vizinhança sobre ele. Levando-se em consideração a incerteza do MDE ASTER-2, essa pesquisa teve por objetivo analisar e mensurar o efeito da mesma sobre a variável declividade, a partir dos indicadores da USGS e da ERSDAC. Para atender esse objetivo, foi empregado o Método de Simulação Monte Carlo de forma a gerar grades de incertezas altimétricas que deram origem a grades de declividade. Essas grades foram averiguadas em relação ao Coeficiente de Variação (CV), destacando-se as seguintes conclusões: (i) as áreas planas são mais difíceis de serem identificadas pelo MDE ASTER-2; (ii) em função do modelo matemático empregado pelo CV, seu valor tende a aumentar exponencialmente a medida que a média das declividades tende a zero e isso acontece em regiões planas; (iii) o menor valor de declividade que pode ser identificado pelo ASTER-2 é 13.89% com um de nível de confiança de 0,05%. Também foi analisada a estratificação da declividade proposta pela EMBRAPA/IBGE, INCRA e Zoneamento Ecológico Econômico (ZEE). Esses órgãos empregam diferentes pontos de corte para as classes e por isso diferentes realidades foram detectadas. Os mapas se mostraram uma excelente forma de interpretar essas realidades.

In the past, the Northern Tampa Bay Area (NTBA) wetlands saw severe declines in hydrologic conditions due to excessive groundwater withdrawal rates. Eventually these rates were reduced to allow the wetlands to recover. To monitor this recovery, the Southwest Florida Water Management district (SWFWMD) set up a fieldwork based scoring methodology, called the Wetlands Assessment Procedure (WAP). WAP has been used in many studies of the area since groundwater withdrawal reductions; with many of those studies finding the recovery to be mixed at best. However, these studies were very limited in the number of wetlands they could assess due to the limitations of fieldwork. Therefore, it was proposed that remotely sensed variables associated with water consumption and stress be used to assess the recovery of the NTBA wetlands, as remote sensing allows for efficient assessments of targets over large area. Utilizing ASTER imagery scenes from 2005 and 2014, 211 wetlands’ remotely sensed responses of NDVI, Land Surface Temperature (LST), and Evapotranspiration (ET) were mapped and statistically examined for trends indicating improvement or decline. Furthermore, a subset of WAP scores for the two years were examined and compared to the remotely sensed values. The results were contradictory, with remotely sensed responses showing an improvement over the time period, WAP scores indicating a decline in hydrologic conditions, and the two methods showing little to no fit when modeled against each other. As such, it is believed at this time that the remotely sensed method is not suitable for measuring the indicators of wetland recovery used in the WAP methodology.

The usage of welding in the process of manufacturing has become very widespread, mainly due to its low cost, versatility and the possibility of its automation. With its expansion comes higher demand for the possibilities of weld evaluation during the phase of design. Nowadays its possible to use tools based on finite element method for such evaluation. But the most commonly used tools are often very expensive. Therefore, the possibility of using Open-Source tool such as Salome-Meca to simulate the welding process as an alternative to commercial software was investigated. The first part of the work deals with the welding process and a description of the formation of residual stresses and deformations. It also deals with the description of the Salome-Meca software environment and the Code-Aster solver. In the next part the capabilities of the software in relation to problem of welding simulation are discussed. Furthermore, the goemetry of solved weldment, welding conditions, material properties and boundary conditions of the calculation are described. And finally, the individual solutions, their results and disadvantages of used approaches.

Thesis advisor: David R. Burgess / Centration of the nucleus after fertilization is an essential step for setting-up cell division and proper embryonic development in many proliferating cells such as the sea urchin. The sperm aster must capture the female pronucleus for fusion as well as the nucleus becoming positioned at the center of the cell. Microtubules (MTs) are known to play a role in this centration but the exact mechanism remains unknown. This begins to investigate current models of nuclear centration and the role of various interactions. Three phases of migration were observed as the male aster migrated with support in independent movements of the male and female pronuclei. Dimpling affects present that altered the morphology of the cell were observed when engagement occurred between the male and female pronuclei. It was discovered that this dimpling effect was a result of an interaction between MTs and the cortex, as confirmed by visualization of sheared cells in which only the cortex remained. Stemming from previous and current research in the lab, the role of post-translational modifications (PMTs) in nuclear centration was investigated for the different forces exerted due to various factors. Tyrosinated and detyrosinated populations were observed with and without the presence of parthenolide (PTL), an agent that inhibits detyrosination. PTL was observed to not only prevent the proper migration, but also that it expanded tyrosination of tubulin – which would further disrupt the force vectors created through the PMTs promotion of dyneins and kinesins. The results have lead to a new hypothesis to be furthered in order to gain an in-depth understanding in the mechanism(s) for pronuclear migration. / Thesis (BS) — Boston College, 2018. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Biology.

Glaciers in the North Patagonian Ice Fields are temperate glaciers and can be studied to understand the dynamics of climate change. However, the ice field has been neglected in mass balance studies. In this study, multi decadal study of glacial mass balance, glacier retreat and glacial lake expansion in the North Patagonia were studied. Landsat (TM, ETM+ and 8) and ASTER images were used. San Quintin glacier experienced the highest retreat. Demarcation of glacier lakes boundaries indicated an increase in glacial lake area from 13.49 km2 to 65.06 km2 between 1979 and 2013, with an addition of 4 new glacial lakes. Nef glacier recorded the highest mass gain of 9.91 plus or minus 1.96 m.w.e.a.-1 and HPN-4 glacier recorded the highest mass loss of -8.9 plus or minus 1.96 m.w.e.a.-1. However, there is a high uncertainty in the elevation values in the DEM due to the rugged nature of the terrain and presence of the heavy snow cover.

Genetic differences evolve between seed sources of widely distributed species that can impact restoration success. Using the herbaceous perennial Geum triflorum (Pursh) as a model species, we examine genetic differences that evolve across a species’ range in both physiology and fitness. G. triflorum occurs across highly differentiated environments consisting of prairie and alvar habitats. Seeds were collected from 22 populations across three eco-geographic regions. Through a common garden experiment in the prairie environment, I first examined differences in physiological traits between source regions and populations. Significant regional differentiation was observed for a majority of traits assessed, with equal or greater trait variation observed at the population scale. Secondly, differences in fitness between source regions were assessed over a period of three years using the ASTER model. Despite being in the home environment, fitness was considerably lower in prairie-sourced plants than alvar sourced plants, both each year and in total.

Glaciers adjust their sizes as a response to changing climatic conditions which make them a good indicator of climate change. Remote-sensing based glacier monitoring provides a robust way to inventory the health of glaciers and are estimated as a measure of changes in their area, length, volume and mass balance over a period. This research uses remote sensing methods to map glacier extents from satellite images and explores the efficacy of three machine learning algorithms for accurate glacier classification. The results indicated that the Columbia icefield lost 42 km2 of its area cover between 1985 and 2018. It was observed that smaller glaciers lost more of their area at a faster pace than larger ones. Change analysis showed the Columbia glacier experienced the highest area loss (-5.62 km2) and retreat (-3.37 km) while the Athabasca glacier recorded the highest mass ice lose (-2.54 m w.e.) over the study period.

Establishing wetland gains and losses, delineating wetland boundaries, and determining their vegetative composition are major challenges that can be improved through remote sensing studies. In this study, we used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to separate wetlands from uplands in a study of 870 locations on the Virginia Coastal Plain. We used the first five bands from each of two ASTER scenes (6 March 2005 and 16 October 2005), covering the visible to the short-wave infrared region (0.52-2.185υm). We included GIS data layers for soil survey, topography, and presence or absence of water in a logistic regression model that predicted the location of over 78% of the wetlands. While this was slightly less accurate (78% vs. 86%) than current National Wetland Inventory (NWI) aerial photo interpretation procedures of locating wetlands, satellite imagery analysis holds great promise for speeding wetland mapping, lowering costs, and improving update frequency. To estimate wetland vegetation composition classs of the study locations, we generated a Classification and Regression Tree (CART) model and a Multinomial Logistic Regression (logit) model, and compared their accuracy in separating woody wetlands, emergent wetlands and open water. The overall accuracy of the CART model was 73.3%, while the overall accuracy of the logit model was 76.7%. Although the CART producer's accuracy (correct category classification) of the emergent wetlands was higher than the accuracy from the multinomial logit (57.1% vs. 40.7%), we obtained the opposite result for the woody wetland category (68.7% vs. 52.6%). A McNemar test between the two models and NWI maps showed that their accuracies were not statistically different. We conducted a sub-pixel analysis of the ASTER images to establish canopy cover of forested wetlands. The canopy cover ranged from 0 to 225 m2. We used visble-near-infrared ASTER bands, Delta Normalized Difference Vegetation Index, and a Tasselled Cap transformation in an ordinary linear regression (OLS) model. The model achieved an adjusted-R2 of 0.69 and an RMSE of 2.73% when the canopy cover is less than 16%. For higher canopy cover values, the adjusted-R2 was 0.4 and the RMSE was19.79%. Taken together, these findings suggest that satellite remote sensing, in concert with other spatial data, has strong potential for mapping both wetland presence and type. / Ph. D.