The study of soil structure allows inferences on soil behavior. Quantitative parameters are oftentimes required to describe soil structure and the multifractal ones are still underused in soil science. Some studies have shown relations between the multifractal spectrum and both soil surface roughness decay by rainfall and porous system heterogeneity, however, a particular multifractal response to a specific soil behavior is not established yet. Therefore, the objectives of this research were: (i) to establish relations between multifractal parameters and soil structure changes by analyzing both soil surface roughness maps and 2D images from impregnated soil blocks; and (ii) to utilize these parameters to evaluate soil surface degradation by the processes of crusting and sealing. An experiment with simulated rainfall was assembled on a Fine Rhodic Kandiudalf with an intensity of 120 mm h-1 in quadruplicate plots at amounts of 40, 80, and 120 mm, plus a no-rainfall control. The evolution of the surface roughness was evaluated in three scales of measurement: a field microrelief meter (MRM) gathered readings on a fixed grid (10 x 10 mm, 640,000 mm²); a multistripe laser triangulation (MLT) scanner was used in the laboratory in soil blocks, creating a random mesh (0.5 mm of resolution, 5625 mm²); an X-ray tomography (XRT) scanner gathered readings of a soil block on a fixed grid (0.074 x 0.074 mm, 900 mm²). For micromorphometrical analysis, undisturbed soil samples (0.12 x 0.07 x 0.05 m) were impregnated, sliced in blocks and polished. Each block was divided into three layers (0 to 10 mm, 20 to 30 mm and 40 to 50 mm), parallel to surface, and five images (10X magnification, 156.25 μm2 pixel-1) were taken by layer. After segmentation, three representative images were chosen by layer and the pore system was evaluated. Roughness analyzes showed no differences (p > 0.10) between multifractal parameters across rainfall amounts for MRM measurements, while both MLT and XRT could be used to model roughness degradation by rainfall increase. Since the last two scales presented similar results, MLT could replace XRT in such analysis, due to its lower cost and possibility of a larger area coverage. The multifractal behavior of pores changed according to sealing development and depth of measurement, being sensitive to the changes on size distribution and fragmentation degree (number of pores) within each size class. The Hausdorff dimensions at the left side of the spectrum (Lf(α)min, LΔf(α) and D2) showed a linear behavior with increasing rainfall amount, considering both soil surface roughness and area of pores measurements. However, D2 was not different (p > 0.10) along rainfalls for the porosity closer to surface, although parameters D0-D1, D0-D2 and D1-D2 could be used to described the changes in this layer. Was concluded that the multifractal spectrum is sensitive to structure changes caused by rainfall and that it can be used to parameterize both soil surface and pores degradation. / O estudo da estrutura do solo permite inferências sobre seu comportamento. Parâmetros quantitativos são comumente utilizados na avaliação da estrutura e os multifractais ainda são subutilizados na ciência do solo. Alguns estudos mostraram relação entre parâmetros multifractais com a diminuição da rugosidade superficial do solo devido à chuva e a heterogeneidade do sistema poroso. No entanto, uma assinatura multifractal relacionada a um comportamento específico do solo ainda não está estabelecida. Portanto, os objetivos desta pesquisa foram: (i) relacionar parâmetros multifractais com mudanças na estrutura do solo por meio da análise de mapas de rugosidade superficial e de imagens 2D provenientes de blocos impregnados de solo; e (ii) utilizar estes parâmetros para identificar as etapas de degradação do solo devido ao selamento e encrostamento superficial. Um experimento com chuva simulada com intensidade de 120 mm h-1 foi montado em uma Nitossolo Vermelho eutroférrico argiloso em parcelas quadruplas onde aplicou-se volumes de 40, 80 e 120 mm, mais um controle sem-chuva. A evolução da rugosidade superficial foi avaliada em três escalas: um rugosímetro de campo (MRM) reuniu leituras numa grade fixa (10 x 10 mm, 640000 mm²); um escâner com triangulação de lasers em multilinhas (MLT) foi usado em laboratório, sobre blocos de solo, criando uma grade aleatório (0,5 mm de resolução, 5625 mm²); um tomógrafo de raios-X (XRT) reuniu leituras de um bloco de solo em uma grade fixa (0,074 x 0,074 mm, de 900 mm²). Para a análise micromorfométrica, amostras de solo indeformado (0,12 x 0,07 x 0,05 m) foram impregnadas, cortadas em blocos, polidas e subdivididas em três camadas (0 a 10 mm, 20 a 30 mm e de 40 a 50 mm), paralelas à superfície, tendo cinco imagens (ampliação de 10x, 156,25 μm2 pixel-1) geradas por camada. Após a segmentação, três imagens foram selecionadas por camada e o sistema poroso foi avaliado. Análises de rugosidade não mostraram diferenças (p > 0.10) entre parâmetros multifractais nas medições da escala MRM, enquanto MLT e XRT puderam ser utilizadas para modelar a degradação da rugosidade com o aumento do volume de chuva. Como essas duas ultimas escalas apresentaram resultados similares, MLT poderia substituir o uso de XRT em tais análises, devido ao seu menor custo e possibilidade de cobrir área mais vasta durante as análises. O comportamento multifractal dos poros mudou de acordo com o desenvolvimento do selamento superficial e da camada avaliada, sendo sensitivo a mudanças no grau de fragmentação (número de poros) dentro de cada classe de tamanho de poros. As dimensões de Hausdorff a esquerda do espectro (Lf(α)min, LΔf(α) and D2) tiveram relação linear com o aumento de volume de chuva para ambas medições de rugosidade superficial do solo e de área de poros. Entretanto, D2 não foi significativo (p > 0.10) entre volumes de chuva para diferenciar a porosidade próxima a superfície, embora os parâmetros D0-D1, D0-D2 e D1-D2 pudessem ser utilizados para descrever mudanças nessa camada. Conclui-se que o espectro multifractal é sensível à mudanças estruturais no solo causadas pela chuva e que pode ser utilizado na parametrização da degradação da rugosidade superficial do solo e da porosidade.

Orientadores: Fernando Roberto Martins, Roque Cielo-Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-11T07:12:22Z (GMT). No. of bitstreams: 1 Rochelle_AndreLuisCasarin_M.pdf: 1478945 bytes, checksum: a4104c9f3c9454316c0218d7e704cc74 (MD5) Previous issue date: 2008 / Resumo: A Floresta Atlântica é um ecossistema complexo, exibindo áreas com mais de 200 espécies de árvores coexistindo em um único hectare. Variações topográficas, principalmente em pequenas escalas, parecem ter forte influência sobre a diversidade, porque estão relacionadas com o processo de formação do substrato e com a disponibilidade de água e nutrientes do solo. Este trabalho investigou a relação entre variáveis microtopográficas e a estrutura da comunidade arbórea em 1 hectare de Floresta Atlântica, no Parque Estadual Serra do Mar, Ubatuba, SP. No capítulo 1, testamos as hipóteses que microvariações topográficas aumentam a diversidade de espécies arbóreas e que microhábitats côncavos possuem maior diversidade que microhábitats convexos, e no capitulo 2, que microhábitats côncavos detêm mais biomassa que microhábitats convexos devido ao predomínio de processos de sedimentação neste tipo de microrrelevo. No capítulo 3, apresentamos uma descrição fitossociológica, discutindo sua diversidade em contextos regionais e continentais. Alocamos 100 parcelas contíguas de 10 x 10 metros (S23º21¿59.8¿¿W45º05¿02.8¿) e etiquetamos, medimos (PAP e altura) e identificamos todas as árvores (PAP>15 cm). Para cada parcela, medimos a inclinação do terreno e calculamos a biomassa acima do solo (BAS) e o índice de convexidade (IC), que é considerado indicador da disponibilidade de água e nutrientes no solo, pois processos erosivos predominam em áreas convexas, tornando-as ambientes mais secos, enquanto nas áreas côncavas predominam processos de sedimentação e acúmulo de água e nutrientes. 51 parcelas são convexas e 49 côncavas. O solo das parcelas côncavas foi significativamente mais úmido que das convexas. Encontramos 1881 indivíduos de 206 espécies, 102 gêneros e 48 famílias (H¿= 4,48 nats.ind-1), sendo 1578 árvores (83,89%), 237 palmeiras (12,59%), 8 samambaias arborescentes (0,42 %) e 58 mortos (3,08 %). Euterpe edulis obteve o maior IVI. Myrtaceae (42), Rubiaceae (18) e Fabaceae (15) foram as famílias mais ricas. Ocorreram duas espécies novas. A diversidade (H¿= 4,48 nats.indivíduo-1) está entre as maiores do Brasil. A BAS estimada foi de 255,553 Mg.ha-1. 804 árvores (104,703 Mg.ha-1) nas côncavas e 1077 árvores (150,850 Mg.ha-1) nas convexas. A BAS não mostrou correlação com o IC ou inclinação e apresentou distribuição aleatória, assim como as grandes arvores, que representam sua maior proporção. A diversidade não mostrou correlação com a inclinação e com heterogeneidade microtopográfica. As parcelas convexas apresentaram mais indivíduos e diversidade, contrariando nossas hipóteses e os resultados de outros autores que diversidade é negativamente correlacionada com posições mais altas da encosta. Argumentamos que em florestas com alta pluviosidade, a umidade do solo poderia atuar como fator restritivo ao estabelecimento dos indivíduos, atuando concomitantemente a várias contrastantes condições microclimáticas imposta pela microtopografia, tais como período de exposição à luz, temperatura e evaporação do solo e do ar e taxas de acúmulo e decomposição de serrapilheira e matéria orgânica, que poderiam atuar como filtros ambientais afetando a germinação e o estabelecimento. Nossos resultados mostraram que heterogeneidade ambiental nem sempre aumenta a diversidade de espécies arbóreas e que as espécies exibem diferentes tolerâncias por hábitat, evidenciando os processos de montagem por nichos em comunidades arbóreas tropicais. Palavras-chave: filtros ambientais, heterogeneidade microtopográfica, modelo de montagem por nichos, microrrelevo, fitossociologia, micro-hábitat / Abstract: Atlantic rainforests are complex ecosystems with areas harboring more than 200 species in a single hectare. Micro-topographic variations appear to be associated with tree species diversity because they are related with the process of soil origin and soil water and nutrient availability. We investigated the relationships between fine-scale micro-topographic variables and tree community structure in 1-ha of Atlantic rainforest at SE Brazil. In chapter 1 we tested the hypotheses that concave sites exhibit higher tree species diversity than convex sites and tree species diversity increase with small-scale microtopographic heterogeneity and in chapter 2, that concave micro-habitats harbor more biomass than convex micro-habitats due to the accumulation processes predominating in the concave microtopography. In chapter 3, we described the tree community structure and compared with other surveys. The sampling area (S23º21¿59.8¿¿O45º05¿02.8¿) was a grid of one hundred 10 x 10 m contiguous plots where all trees with DBH > 4.8 cm were tagged, measured (DBH and height) and identified. In each plot, we measured slope inclination, estimated the above-ground biomass (AGB), and calculated the index of convexity (IC), which is considered to reflect the soil water and nutrient availability because erosive processes predominate in convex areas, implying in drier and less fertile micro-sites, whereas accumulation processes prevail in concave areas, producing moister and more fertile micro-sites. 51 plots are convex and 49 are concave. Soil in concave sites was significantly (p=0.04) moister than in convex. We sampled 1881 trees of 206 species, 102 genera and 48 families (H¿= 4.48 nats.inds-1). 1578 stems were trees (83,89%), 237 palms (12,59%), 8 ferns (0,42 %) and 58 standing dead trees (3,08 %). Euterpe edulis had the highest IVI. Myrtaceae (42), Rubiaceae (18) e Fabaceae (15) were the richest families. We found two new species. The diversity (H¿= 4.48 nats.indivíduo-1) is among the highest recorded in Brazil. The estimated AGB was 255.553 Mg C.ha-1. 804 trees (104.703 Mg C.ha-1) in concave plots and 1077 trees (150.850 Mg C.ha-1) in convex. AGB was not correlated with IC or inclination and had a random distribution because the greatest proportion of AGB was yielded by large trees, which also had a random pattern. Diversity had no correlation with inclination and micro-topographic heterogeneity. Convex plots harbored significantly more individuals and species than concave plots, which contradicted our hypotheses that expected a negative correlation between diversity (and AGB) and convexity and other author¿s findings that diversity is negatively correlated with higher positions on slope. We argue that in forests with abundant rainfall and without a dry season, the high soil water content could restrain the establishment of some individuals, together with several microclimatic conditions imposed by the microtopography, such as sunlight exposure, ground and air temperature and evaporation, and litter and organic matter accumulation and decomposition rates, that could act as environmental filters and affects species germination and performance. Our results show that environmental heterogeneity does not always increase tree species diversity and that species do have habitat preferences and tolerances evidencing niche assembly processes in tropical tree communities. Keywords: environmental filters, microtopographic heterogeneity, niche-assembly model, micro-relief, phytosociology, micro-habitats, concave, convex / Mestrado / Mestre em Biologia Vegetal

The study of soil structure allows inferences on soil behavior. Quantitative parameters are oftentimes required to describe soil structure and the multifractal ones are still underused in soil science. Some studies have shown relations between the multifractal spectrum and both soil surface roughness decay by rainfall and porous system heterogeneity, however, a particular multifractal response to a specific soil behavior is not established yet. Therefore, the objectives of this research were: (i) to establish relations between multifractal parameters and soil structure changes by analyzing both soil surface roughness maps and 2D images from impregnated soil blocks; and (ii) to utilize these parameters to evaluate soil surface degradation by the processes of crusting and sealing. An experiment with simulated rainfall was assembled on a Fine Rhodic Kandiudalf with an intensity of 120 mm h-1 in quadruplicate plots at amounts of 40, 80, and 120 mm, plus a no-rainfall control. The evolution of the surface roughness was evaluated in three scales of measurement: a field microrelief meter (MRM) gathered readings on a fixed grid (10 x 10 mm, 640,000 mm²); a multistripe laser triangulation (MLT) scanner was used in the laboratory in soil blocks, creating a random mesh (0.5 mm of resolution, 5625 mm²); an X-ray tomography (XRT) scanner gathered readings of a soil block on a fixed grid (0.074 x 0.074 mm, 900 mm²). For micromorphometrical analysis, undisturbed soil samples (0.12 x 0.07 x 0.05 m) were impregnated, sliced in blocks and polished. Each block was divided into three layers (0 to 10 mm, 20 to 30 mm and 40 to 50 mm), parallel to surface, and five images (10X magnification, 156.25 μm2 pixel-1) were taken by layer. After segmentation, three representative images were chosen by layer and the pore system was evaluated. Roughness analyzes showed no differences (p > 0.10) between multifractal parameters across rainfall amounts for MRM measurements, while both MLT and XRT could be used to model roughness degradation by rainfall increase. Since the last two scales presented similar results, MLT could replace XRT in such analysis, due to its lower cost and possibility of a larger area coverage. The multifractal behavior of pores changed according to sealing development and depth of measurement, being sensitive to the changes on size distribution and fragmentation degree (number of pores) within each size class. The Hausdorff dimensions at the left side of the spectrum (Lf(α)min, LΔf(α) and D2) showed a linear behavior with increasing rainfall amount, considering both soil surface roughness and area of pores measurements. However, D2 was not different (p > 0.10) along rainfalls for the porosity closer to surface, although parameters D0-D1, D0-D2 and D1-D2 could be used to described the changes in this layer. Was concluded that the multifractal spectrum is sensitive to structure changes caused by rainfall and that it can be used to parameterize both soil surface and pores degradation. / O estudo da estrutura do solo permite inferências sobre seu comportamento. Parâmetros quantitativos são comumente utilizados na avaliação da estrutura e os multifractais ainda são subutilizados na ciência do solo. Alguns estudos mostraram relação entre parâmetros multifractais com a diminuição da rugosidade superficial do solo devido à chuva e a heterogeneidade do sistema poroso. No entanto, uma assinatura multifractal relacionada a um comportamento específico do solo ainda não está estabelecida. Portanto, os objetivos desta pesquisa foram: (i) relacionar parâmetros multifractais com mudanças na estrutura do solo por meio da análise de mapas de rugosidade superficial e de imagens 2D provenientes de blocos impregnados de solo; e (ii) utilizar estes parâmetros para identificar as etapas de degradação do solo devido ao selamento e encrostamento superficial. Um experimento com chuva simulada com intensidade de 120 mm h-1 foi montado em uma Nitossolo Vermelho eutroférrico argiloso em parcelas quadruplas onde aplicou-se volumes de 40, 80 e 120 mm, mais um controle sem-chuva. A evolução da rugosidade superficial foi avaliada em três escalas: um rugosímetro de campo (MRM) reuniu leituras numa grade fixa (10 x 10 mm, 640000 mm²); um escâner com triangulação de lasers em multilinhas (MLT) foi usado em laboratório, sobre blocos de solo, criando uma grade aleatório (0,5 mm de resolução, 5625 mm²); um tomógrafo de raios-X (XRT) reuniu leituras de um bloco de solo em uma grade fixa (0,074 x 0,074 mm, de 900 mm²). Para a análise micromorfométrica, amostras de solo indeformado (0,12 x 0,07 x 0,05 m) foram impregnadas, cortadas em blocos, polidas e subdivididas em três camadas (0 a 10 mm, 20 a 30 mm e de 40 a 50 mm), paralelas à superfície, tendo cinco imagens (ampliação de 10x, 156,25 μm2 pixel-1) geradas por camada. Após a segmentação, três imagens foram selecionadas por camada e o sistema poroso foi avaliado. Análises de rugosidade não mostraram diferenças (p > 0.10) entre parâmetros multifractais nas medições da escala MRM, enquanto MLT e XRT puderam ser utilizadas para modelar a degradação da rugosidade com o aumento do volume de chuva. Como essas duas ultimas escalas apresentaram resultados similares, MLT poderia substituir o uso de XRT em tais análises, devido ao seu menor custo e possibilidade de cobrir área mais vasta durante as análises. O comportamento multifractal dos poros mudou de acordo com o desenvolvimento do selamento superficial e da camada avaliada, sendo sensitivo a mudanças no grau de fragmentação (número de poros) dentro de cada classe de tamanho de poros. As dimensões de Hausdorff a esquerda do espectro (Lf(α)min, LΔf(α) and D2) tiveram relação linear com o aumento de volume de chuva para ambas medições de rugosidade superficial do solo e de área de poros. Entretanto, D2 não foi significativo (p > 0.10) entre volumes de chuva para diferenciar a porosidade próxima a superfície, embora os parâmetros D0-D1, D0-D2 e D1-D2 pudessem ser utilizados para descrever mudanças nessa camada. Conclui-se que o espectro multifractal é sensível à mudanças estruturais no solo causadas pela chuva e que pode ser utilizado na parametrização da degradação da rugosidade superficial do solo e da porosidade.

Arctic soils store close to 14% of the global soil carbon. Most of arctic carbon is stored below ground in the permafrost. With climate warming the decomposition of the soil carbon could represent a significant positive feedback to global greenhouse warming. Recent evidence has shown that the temperature of the Arctic is already increasing, and this change is associated mostly with anthropogenic activities. Warmer soils will contribute to permafrost degradation and accelerate organic matter decay and thus increase the flux of carbon dioxide and methane into the atmosphere. Temperature and water availability are also important drivers of ecosystem performance, but effects can be complex and in opposition. Temperature and moisture changes can affect ecosystem respiration (ER) and gross primary productivity (GPP) independently; an increase in the net ecosystem exchange can be a result of either a decrease in ER or an increase in GPP. Therefore, understanding the effects of changes in ecosystem water and temperature on the carbon flux components becomes key to predicting the responses of the Arctic to climate change. The overall goal of this work was to determine the response of arctic systems to simulated climate change scenarios with simultaneous changes in temperature and moisture. A temperature and hydrological manipulation in a naturally-drained lakebed was used to assess the short-term effect of changes in water and temperature on the carbon cycle. Also, as part of International Tundra Experiment Network (ITEX), I determined the long-term effect of warming on the carbon cycle in a natural hydrological gradient established in the mid 90’s. I found that the carbon balance is highly sensitive to short-term changes in water table and warming. However, over longer time periods, hydrological and temperature changed soil biophysical properties, nutrient cycles, and other ecosystem structural and functional components that down regulated GPP and ER, especially in wet areas.

Disturbances are ubiquitous features of most northern forest ecosystems. The subsequent response of plant assemblages on both short (resistance or not) and long term (recolonization or not) will depend on a number of factors operating at several spatial scales. In boreal forest ecosystems, bryophyte assemblages are a conspicuous and species rich group of plants for which these processes are poorly understood. Using a combination of experimental and observational approaches this thesis explores these questions for closed-canopy bryophyte assemblages in relation to a) microtopography (both for the initial and long-term response), b) environmental constrains during post-logging succession and c) disturbance type. My results clearly show that the shade and shelter provided by microtopographic surface structures can increase survival rates of bryophytes following clear-cut logging by decreasing mortality from microclimatic stress and mechanical disturbance. Following clear-cutting, the recovery of forest floor and dead wood living bryophytes seems to be a relatively steady and progressive process without any major bottleneck episodes in the young or semi-mature forest stages with much of the pre-disturbance composition recovered after 50 years. Although boulders were found to increase the initial survival on clear-cuts and hence increase disturbance resistance, we found no evidence that boulders influenced the subsequent recolonization process. Lastly, strong compositional dissimilarities were found in young forests (40 years) following clear-cut logging, wildfire and insect outbreak, indicating divergent trajectories to occur following different disturbances. Hence, early seral stages of forest ecosystems regenerating after natural disturbances seem to compliment young managed forests in maintaining landscape level diversity. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript. Paper 4: Manuscript.

A comprehensive understanding of the interactions between orthopaedic and dental implant surfaces with the surrounding host tissue is essential in the design of advanced biomaterials that better promote bone growth and osseointegration of implants. Dental implants with roughened surfaces and high surface energy are well known to promote osteoblast differentiation in vitro and promote increased bone-to-implant contact in vivo. In addition, increased surface roughness increases osteoblasts response to the vitamin D metabolite 1α,25(OH)2D3. However, the exact mechanisms mediating cell response to surface properties and 1α,25(OH)2D3 are still being elucidated. The central aim of the thesis is to investigate whether integrin signaling in response to rough surface microtopography enhances osteoblast differentiation and responsiveness to 1α,25(OH)2D3. The hypothesis is that the integrin α5β1 plays a role in osteoblast response to surface microtopography and that 1α,25(OH)2D3 acts through VDR-independent pathways involving caveolae to synergistically enhance osteoblast response to surface roughness and 1α,25(OH)2D3. To test this hypothesis the objectives of the studies performed in this thesis were: 1) to determine if α5β1 signaling is required for osteoblast response to surface microstructure; 2) to determine if increased responsiveness to 1α,25(OH)2D3 requires the vitamin D receptor, 3) to determine if rough titanium surfaces functionalized with the peptides targeting integrins (RGD) and transmembrane proteoglycans (KRSR) will enhance both osteoblast proliferation and differentiation, and 4) to determine whether caveolae, which are associated with integrin and 1α,25(OH)2D3 signaling, are required for enhance osteogenic response to surface microstructure and 1α,25(OH)2D3. The results demonstrate that integrins, VDR, and caveolae play important roles in mediating osteoblast response to surface properties and 1α,25(OH)2D3. Silencing of the β1 integrin in osteoblast-like MG63 cells significantly reduced osteogenic response to surface topography and 1α,25(OH)2D3. Silencing of the α5 subunit did not alter the response of MG63 cells to changing surface roughness or chemistry, although future work must confirm these results given similar cell surface α5 integrin expression observed in control and α5-silenced cells. Multifunctional RGD, KRSR, and KSSR coated surfaces show that RGD increased osteoblast proliferation and reduced differentiation, KRSR had no affect on osteoblast phenotype, and KSSR increased osteoblast differentiation. These results suggest that titanium surfaces can be modified to manipulate proliferation and differentiation and that RGD/KSSR functionalized surfaces could be further investigated for use as osteointegrative surfaces. The results using VDR deficient osteoblasts demonstrate that 1α,25(OH)2D3 acts via VDR-dependent mechanisms in cells cultured on titanium surfaces that support terminal differentiation. In caveolae deficient osteoblasts, 1α,25(OH)2D3 affected cell number, alkaline phosphatase activity, and TGF-β1 levels, although levels of osteocalcin and PGE2 were not affected. These results are consistent with the hypothesis that VDR is required for the actions of 1α,25(OH)2D3, but that caveolae-dependent membrane 1α,25(OH)2D3 signaling modulates traditional VDR signaling. The exact mechanisms for this interaction remain to be shown. Overall, these results are important in better understanding the role of β1 integrin partners in mediating osteoblast response to implant surfaces and in understanding how integrin signaling can alter osteoblast differentiation and responsiveness to 1α,25(OH)2D3 via genomic and non-genomic pathways.

Orientador: Marco Antonio de Assis / Banca: Leonor Patricia Cerdeira Morellato / Banca: Marcia Cristina Mendes Marques / Resumo: Estudos abrangendo aspectos da ecologia populacional de plantas fornecem informações importantes sobre os processos de regeneração, ocorrência de perturbações e os meios pelos quais as espécies exploram seus ambientes. Estudos dessa natureza em Florestas de Restinga, feições marcantes no litoral brasileiro, ainda são escassos. Assim, no presente trabalho foram investigados alguns aspectos da ecologia populacional de Calophyllum brasiliense Cambess. (Clusiaceae), uma espécie de ampla ocorrência em ambienteis sujeitos à inundação nas florestas Neotropicais, em 0,5 ha de Floresta de Restinga, localizada no Parque Estadual da Serra do Mar, Núcleo Picinguaba, Ubatuba, SP. Foi realizada uma análise temporal da estrutura de tamanho e do padrão de distribuição espacial da população, visando compreender como a heterogeneidade ambiental, relacionada às variações na microtopografia (mosaico de regiões sobre e entre cordões arenosos), na abertura do dossel da floresta e nas condições de drenagem do solo, afeta os parâmetros da estrutura populacional analisados. Observou-se que a população apresenta estrutura com predomínio de indivíduos nas menores classes de tamanho e distribuição agregada em todas as classes (plântulas, jovens, imaturos e adultos). A saturação hídrica do solo e as diferenças na microtopografia dos cordões arenosos influenciaram o padrão encontrado e afetaram os parâmetros demográficos, entretanto, não foram encontradas correlações entre a abertura de dossel e os parâmetros analisados. Além disso, a análise da estrutura de tamanho em subclasses de altura revelou ausência de indivíduos com alturas entre três e 15 metros, o que pode ser um indicativo de que apesar da população apresentar representantes em todas as classes de tamanho, o acesso dos indivíduos à classe reprodutiva está comprometido... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Studies concerning plant population ecology provide important information about status of regeneration, occurrence of disturbances and the means by which the species exploit the environment. Studies like these, in the "Restingas" forests, striking features in the Brazilian coast, are still scarce. Therefore, we investigated some aspects of population ecology of Calophyllum brasiliense Cambess. (Clusiaceae), in 0.5 ha of the Restinga Forest, in the "Parque Estadual da Serra do Mar", "Núcleo Picinguaba", Municipality of Ubatuba, São Paulo State. We performed a temporal analysis of size structure and spatial pattern, to understand how the environmental heterogeneity, such as microtopography variations, light availability and soil drainage conditions can affect the population structure. Population structure presented dominance of individuals in lower size classes as well as aggregated distribution. These patterns result of both drainage and microtopography conditions, however, no correlations were found between canopy openness and the parameters analyzed. In addition, the size structure analysis, performed into different height classes, showed no individuals with heights between 3 and 15 m, which can suggest that the access to reproductive class seems to be compromised, even though there were individuals within all size classes. It was also observed a high frequency of herbivory damage; however, such damage did not contribute to increase the mortality rate of the population. In general, it could be concluded that environmental heterogeneity has a major influence on the size structure and spatial distribution, mainly in smaller size classes, and that the population seems to have trouble reaching the reproductive stage, which can lead, as a long term, to its disappearance in the area. / Mestre

Made available in DSpace on 2014-06-11T19:23:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-09-02Bitstream added on 2014-06-13T20:29:42Z : No. of bitstreams: 1 freitas_dv_me_rcla.pdf: 971560 bytes, checksum: 12bf77581a5c1c40a7b070f7afebb636 (MD5) / Estudos abrangendo aspectos da ecologia populacional de plantas fornecem informações importantes sobre os processos de regeneração, ocorrência de perturbações e os meios pelos quais as espécies exploram seus ambientes. Estudos dessa natureza em Florestas de Restinga, feições marcantes no litoral brasileiro, ainda são escassos. Assim, no presente trabalho foram investigados alguns aspectos da ecologia populacional de Calophyllum brasiliense Cambess. (Clusiaceae), uma espécie de ampla ocorrência em ambienteis sujeitos à inundação nas florestas Neotropicais, em 0,5 ha de Floresta de Restinga, localizada no Parque Estadual da Serra do Mar, Núcleo Picinguaba, Ubatuba, SP. Foi realizada uma análise temporal da estrutura de tamanho e do padrão de distribuição espacial da população, visando compreender como a heterogeneidade ambiental, relacionada às variações na microtopografia (mosaico de regiões sobre e entre cordões arenosos), na abertura do dossel da floresta e nas condições de drenagem do solo, afeta os parâmetros da estrutura populacional analisados. Observou-se que a população apresenta estrutura com predomínio de indivíduos nas menores classes de tamanho e distribuição agregada em todas as classes (plântulas, jovens, imaturos e adultos). A saturação hídrica do solo e as diferenças na microtopografia dos cordões arenosos influenciaram o padrão encontrado e afetaram os parâmetros demográficos, entretanto, não foram encontradas correlações entre a abertura de dossel e os parâmetros analisados. Além disso, a análise da estrutura de tamanho em subclasses de altura revelou ausência de indivíduos com alturas entre três e 15 metros, o que pode ser um indicativo de que apesar da população apresentar representantes em todas as classes de tamanho, o acesso dos indivíduos à classe reprodutiva está comprometido... / Studies concerning plant population ecology provide important information about status of regeneration, occurrence of disturbances and the means by which the species exploit the environment. Studies like these, in the “Restingas” forests, striking features in the Brazilian coast, are still scarce. Therefore, we investigated some aspects of population ecology of Calophyllum brasiliense Cambess. (Clusiaceae), in 0.5 ha of the Restinga Forest, in the “Parque Estadual da Serra do Mar”, “Núcleo Picinguaba”, Municipality of Ubatuba, São Paulo State. We performed a temporal analysis of size structure and spatial pattern, to understand how the environmental heterogeneity, such as microtopography variations, light availability and soil drainage conditions can affect the population structure. Population structure presented dominance of individuals in lower size classes as well as aggregated distribution. These patterns result of both drainage and microtopography conditions, however, no correlations were found between canopy openness and the parameters analyzed. In addition, the size structure analysis, performed into different height classes, showed no individuals with heights between 3 and 15 m, which can suggest that the access to reproductive class seems to be compromised, even though there were individuals within all size classes. It was also observed a high frequency of herbivory damage; however, such damage did not contribute to increase the mortality rate of the population. In general, it could be concluded that environmental heterogeneity has a major influence on the size structure and spatial distribution, mainly in smaller size classes, and that the population seems to have trouble reaching the reproductive stage, which can lead, as a long term, to its disappearance in the area.

Wetlands serve important ecosystem functions such as carbon sequestration but are often affected by disturbances like urban development, agriculture, and road building. For wetlands created to mitigate losses, it is important that the ecosystem functions successfully replicate those of natural wetlands. Created wetlands have frequently not provided these functions due to issues including low organic carbon (OC), high soil bulk density (BD), lost topsoil, incorrect hydrology, and failure of targeted vegetation establishment. Organic matter (OM) amendments help created wetlands attain these functions quicker, but, their long-term effects are seldom reported. This research's purpose was to measure the long-term effects of treatments at a sandy tidal freshwater wetland created in 2003 (WWE) and a fine-textured, non-tidal wetland created in 2002 (CCW). We tested OM treatments, topsoil amendment, and microtopography effects on soil and vegetation properties at WWE and OM treatments at CCW. Pedogenic changes in soil morphology, physical and chemical properties were detected by comparing data to previous studies at these sites. At both sites, litter and biomass parameters were measured to estimate total mass C. Herbaceous biomass was measured at WWE. At WWE, no long-term OM treatment effects from 78 or 156 Mg ha-1 were observed. Soils in pits had higher OC, lower BD, and lower chroma than soils on mounds. Sandy and loamy HSFI's developed at WWE within four years, but there were fewer sandy indicators after 12 years. Loamy HSFI's were lost at CCW from 2003 to 2016. Plots at WWE that were amended with topsoil had higher soil mass C than the sandy soil due to a finer texture, but total mass C did not vary. At CCW, long-term OM treatment effects were observed, including lower BD, higher soil mass C, and higher tree mass C with increasing compost rates up to 224 Mg ha-1. Overall, the ideal compost loading rate for constructed wetlands varied with wetland type and mitigation goals. Compost rates of 112 Mg ha-1 are sufficient for short term establishment of wetland vegetation and hydric soil properties, but higher rates near 224 Mg ha-1 may be required for effects that last over 10 years. / Ph. D.

Afin de mieux comprendre les effets des changements climatiques sur le pergélisol, il s’avère essentiel d’obtenir une meilleure connaissance des facteurs physiques et biologiques l’influençant. Même si plusieurs études font référence à l’influence de la végétation sur le pergélisol à grande échelle, l’effet de la végétation sur la profondeur du front de dégel du pergélisol à l’échelle de mètres, tel qu’exploré ici, est peu connu. L’étude s’est effectuée dans une forêt boréale tourbeuse dans la zone à pergélisol discontinu au sud des Territoires du Nord-Ouest (N61°18’, O121°18’). Nous avons comparé la profondeur de dégel aux mesures du couvert végétal suivantes : densité arborescente, couvert arbustif, indice de surface foliaire et présence de cryptogames (lichens et bryophytes). Nous avons trouvé qu’une plus grande densité arborescente menait à une moins grande profondeur de dégel tandis que le couvert arbustif (<50cm de hauteur) n’avait aucune influence. De plus, la profondeur de dégel dépendait de l’espèce des cryptogames et des microformes. Cette recherche quantifie l’influence de la végétation par strate sur la dégradation du pergélisol. Ultimement, les résultats pourront être pris en considération dans la mise en place des modèles, afin de valider les paramètres concernant la végétation, la dégradation du pergélisol et le flux du carbone. / In order to better understand the impacts of climate change on permafrost degradation, it is important to understand the influence of abiotic and biotic factors on permafrost dynamics. While studies allude to the effect of broad vegetation groups on permafrost dynamics at landscape-scale, the role vegetation plays in affecting the spatial variability of active-layer development on the scale of metres, as explored here, is largely unknown. The study was carried out in a boreal forest-peatland landscape in the discontinuous permafrost zone in the southern Northwest Territories (N61°18’, W121°18’). We examined the influence of the following vegetation characteristics on the spatial variability of thaw depth: tree density, shrub cover, leaf area index, and cryptogam presence (lichen and bryophyte). We found that greater tree density was associated with shallower thaw depths while shrub cover (<50cm height) had a negligible influence. Furthermore, thaw depth depended on the cryptogam species cover and microform. This research quantifies the impact of vegetation by strata on thaw depth and may ultimately serve to refine vegetation parameters in ecosystem models and land surface schemes as part of climate models.