The presence of annual density banding in certain long-lived reef-building corals provides a record of the coral’s growth rate over time in response to changing environmental conditions. Coral growth is best described by three parameters: linear extension, bulk density, and calcification. Coral growth is generally controlled by the combined influences of light, temperature, and water quality; however, corals are highly responsive to their surrounding conditions and thus record environmental variations through their rates and patterns of skeletal accretion. Because coral growth rates reflect environmental conditions over time, they allow testing of hypotheses regarding the effects of climate change, more specifically global warming which affects sea surface temperatures and rising atmospheric carbon dioxide which affect the aragonite saturation state of seawater. Influences on coral growth include local changes in sea surface temperature and rainfall as well as large scale climatic indices such as the Atlantic Multidecadal Oscillation (AMO), the North Atlantic Oscillation (NAO), and the Southern Oscillation Index (SOI). Chapter 1, Background, reviews the current state of knowledge in three primary areas: 1) coral biology, growth, density band formation, and measurement of extension, density, and calcification, 2) potential climate change impacts on coral growth, and 3) long-term coral growth records. This section is broadly intended to review the literature, identify possible information gaps, and recognize current debate within coral and climate change research. Chapter 2, Sample Size for Coral Sclerochronology, presents data of sample size correlations based on statistical analyses of annual extension rates. A standardized period (1970-1985) of annual extension rates from the largest number of Montastraea faveolata samples available from southeast Florida (136 corals) was used to test correlation on varying spatial scales and to determine sample size requirements for desired levels of correlation based on objective criteria. The results provide basic information on masterchronology construction for sclerochronological growth rate studies and provide a framework from which further growth rate variability can be assessed. Extension and bulk density can be measured from X-ray films of coral skeletal slabs and can be used to calculate calcification. Chapter 3, Relative Optical Densitometry, describes the techniques and associated errors through the process of coral coring, sectioning, X-raying, developing, digitizing, calibrating and analyzing. The principles of relative optical densitometry and the calculation of mass absorption coefficient ratios for aragonite and aluminum standards are explained. Calculated and measured errors are quantified to define the accuracy and precision of these techniques necessary to detect potentially subtle changes in coral growth caused by climate change. Coral cores from the Florida Key, USA, were used to construct growth records over a 60-yr period from 1973-1996. Chapter 4, Coral Growth Records and Climate Change, uses linear extension rate, bulk-density, and calcification rate from annual and sub-annual bands in order to assess: 1) growth averages, variability, and relationships between growth parameters, 2) long term trends with respect to rising carbon dioxide levels and sea surface temperature, 3) correlation with local environmental variables of temperature and rainfall, and 4) correlation with major climate indices of Atlantic Multidecadal Oscillation, North Atlantic Oscillation, and the Southern Oscillation.

Made available in DSpace on 2016-07-18T17:53:16Z (GMT). No. of bitstreams: 1 Leandro Barbosa.pdf: 680328 bytes, checksum: 22ee01e97ffce340763c0803b4b252c2 (MD5) Previous issue date: 2015-04-09 / The objective of this study is to evaluate the effect of manann oligosaccharides (MOS) prebiotics on densitometry parameters of the femur by means of bone densitometry and biomechanical test in rats. 144 growing male rats were used, 23 days old, and 36.7 ± 0.6 grams of body weight were divided into 04 experimental groups (n = 36) and kept in individual cages during the experimental period of 56 days: Group Control (GC); Mos Group 1 (GM1); Mos Group 2 (GM2); and Group 3 Mos (GM3). Densitometric analysis and biomechanical testing of bone mineral content were conducted in four stages: 14, 28, 42 and 56 days after beginning the experiment. Simple linear regressions were adjusted data pairs situation, time of collection (every 14 days) and results of bone mineral content parameters (BMC), bone mineral density (BMD), area (A), energy, maximum strength and stiffness. The regressions set of treatments for each parameter were compared in pairs by the intercept and slope of the straight and revealed significant differences between treatments (P <0.0125) in the area parameters, energy absorbed to the maximum strength and maximum strength. The slope of the lines was higher in groups supplemented with MOS compared to the CG. MOS intake increased bone mineralization, which, in turn, increased the resistance to fracture of the femur in all the biomechanical properties and densitometric studied, perhaps due to an increase in the intestinal absorption of nutrients in rats. Given the beneficial results of this study with growing rats as experimental model, it is suggested that this functional food can be used as a food component enhancing bone health. / O objetivo deste estudo é avaliar o efeito dos aditivos prebióticos do tipo mananoligossacarídeos (MOS) sobre os parâmetros densitométricos e biomecânicos, por meio da densitometria óssea e ensaio biomecânico, respectivamente, de fêmures de ratos. Foram utilizados 144 ratos machos em crescimento, com 23 dias de idade e 36,7 ± 0,6 gramas de massa corporal, divididos em 04 grupos experimentais (n=36) e mantidos em gaiolas individuais durante o período experimental de 56 dias: Grupo Controle (GC); Grupo MOS 1 (GM1); Grupo MOS 2 (GM2); e Grupo MOS 3 (GM3). A análise densitométrica e o ensaio biomecânico do conteúdo mineral ósseo foram realizadas em quatro momentos: 14, 28, 42 e 56 dias após o inicio do experimento. Foram ajustadas regressões lineares simples, situação de pares de dados, momento de coleta (a cada 14 dias) e resultados dos parâmetros do conteúdo mineral ósseo (CMO), densidade mineral óssea (DMO), área (A), energia, força máxima e rigidez. As regressões ajustadas dos tratamentos de cada parâmetro foram comparadas duas a duas pelos interceptos e inclinação das retas e revelaram diferenças significativas entre os tratamentos (P<0,0125) nos parâmetros área, energia absorvida até a força máxima e força máxima. A inclinação das retas foi maior nos grupos suplementados com MOS em relação ao GC. A ingestão de MOS resultou em uma maior mineralização óssea, o que, por sua vez, aumentou a resistência à fratura do fêmur em todas as propriedades biomecânicas e densitométricas estudadas, talvez devido a um aumento da absorção intestinal de nutrientes nos ratos. Diante dos benéficos resultados obtidos nesse estudo com ratos em crescimento, como modelo experimental, sugere-se que este alimento funcional possa ser utilizado como um componente alimentar intensificador da saúde óssea, particularmente nos dias de hoje, em que a expectativa de vida aumenta exponencialmente.

Zweiphasenströmungen sind Strömungen von heterogenen Stoffgemischen, die aus zwei verschiedenen und voneinander getrennten homogenen Materialien, den Phasen, bestehen und bei einer Vielzahl technischer Anwendungen auftreten, wie zum Beispiel in der chemischen Industrie und der Energietechnik. Dort beeinflussen Zweiphasenströmungen maßgeblich die Prozesseffizienz und -sicherheit. Radiometrische Messverfahren bieten aufgrund ihrer Nicht-invasivität und dem hohen Durchdringungsvermögen die Möglichkeit, diese Strömungen zu visualisieren sowie deren Parameter zur Charakterisierung zu bestimmen. Die quantitativ hoch-genaue Parameterbestimmung kann dabei durch einige Aspekte erschwert werden, die bisher nicht durch Standardalgorithmen berücksichtigt werden können. Bei der Bestimmung von zeitgemittelten Phasenanteilen durch densitometrische und tomo-graphische Messungen kann bei geringen Zählraten die dynamische Verzerrung auftreten, die systematisch zu einer Verfälschung der zu bestimmenden Phasenanteile führt. Mit dem in dieser Arbeit entwickelten Verfahren des korrekten Mittelns kann die dynamische Verzerrung voll-ständig korrigiert werden. Bei der Anwendung des Verfahrens des korrekten Mittelns müssen schlecht konditionierte lineare Gleichungssysteme gelöst werden. Durch geeignete Regularisierungsverfahren lassen sich die Abweichungen vom Mittelwert bei ausreichender Zählratenstatistik beliebig stark verringern. Der Ansatz des Verfahrens des korrekten Mittelns kann bei densitometrischen Messungen von Gas-Flüssigkeits-Strömungen genutzt werden, um auf Basis der Gasgehalts-Wahrscheinlichkeitsdichte das Strömungsregime bei geringen Zähl-raten zu ermitteln. Die Röntgencomputertomographie ermöglicht die Bestimmung von räumlich und zeitlich aufgelösten Phasenverteilungen. Durch Strahlaufhärtung, Streustrahlung und geometrische Verzerrungen können die rekonstruierten Bilder Artefakte enthalten, die die Phasenanteile signifikant verfälschen. Streustrahlung und Strahlaufhärtung können beim ultraschnellen Elektronenstrahl-Röntgencomputertomographen ROFEX durch geeignete Normierungen mit Referenzmessdaten erheblich verringert werden. Weitere Reduktionen der Streustrahlungs-artefakte lassen sich durch Kollimation und einer strahlwegbasierten Vorwärtssimulation der Streustrahlung in der Bildebene erreichen. Durch äußere Einflüsse kann es beim ROFEX zu unerwünschten Ablenkungen des freien Elektronenstrahls kommen, was zu Verzerrungen in den Bildern führt. Die Korrektur kann mithilfe eines iterativen Algorithmus erfolgen, der auf Basis der Schärfe der Bilddaten den Pfad des Elektronenstrahls schätzt und somit die exakte Strahlweggeometrie für die Bildrekonstruktion ermittelt. / Two-phase flows are flows of heterogeneous material mixtures consisting of two different and separated homogeneous materials, the phases, which occur in many technical applications, such as in the chemical industry and energy technology. There, two-phase flows have a significant influence on process efficiency and safety. Due to their non-invasiveness and high penetration capability, radiometric measurement methods offer the possibility of visualizing these flows and determining their parameters for characterization. The quantitative high-precision determination of parameters is hampered by some aspects that are not taken into account by standard algorithms. When determining time-averaged phase fractions by densitometric and tomographic measurements, the dynamic bias error can occur at low count rates, which systematically leads to a falsification of the phase fractions to be determined. With the correct averaging method developed in this thesis, the dynamic bias error can be completely corrected. When applying the correct averaging method, ill-conditioned linear equation systems have to be solved. By suitable regularization methods, the deviations from the exact mean value can be reduced arbitrarily strongly with sufficient count rate statistics. The approach of the correct averaging method can be used for densitometric measurements of gas-liquid flows to determine the flow regime at low count rates on the basis of the gas fraction probability density. X-ray computed tomography enables the determination of spatially and temporally resolved phase distributions. The reconstructed images can contain artifacts due to beam hardening, scattered radiation and geometric distortions, which significantly falsify the phase fractions. In the ROFEX ultrafast electron beam X-ray computer tomography system, scattered radiation and beam hardening can be significantly reduced by suitable normalization with reference measurement data. Further reductions of scatter artifacts can be achieved by collimation and ray-tracking based forward simulation of scattered radiation in the image plane. Due to external influences around the ROFEX, undesired deflections of the free electron beam can occur, which leads to distortions in the images. The correction can be performed using an iterative algorithm that estimates the path of the electron beam based on the sharpness of the image data and thus determines the exact beam path geometry for the image reconstruction.

Indiana University-Purdue University Indianapolis (IUPUI) / Mechanical loading associated with exercise is known to benefit bone health; however, most studies explore exercise benefits on bone mass independent of bone structure and strength. The purpose of this dissertation is to explore the response of the skeleton to exercise across the translational divide between animal- and human-based studies, with a particular emphasis on exercise-induced changes in bone structure and estimated strength. To explore the skeletal benefits of exercise, models were used wherein loading is introduced unilaterally to one extremity. Unilateral exercise enables the contralateral, non-exercised extremity to be used as an internal control site for the influences of systemic factors, such as genetics and circulating hormones. In study 1, a dose response between load magnitude and tibial midshaft cortical bone adaptation was observed in mice that had their right tibia loaded in axial compression at one of three load magnitudes for 3 d/wk over 4 weeks. In study 2, the ability of peripheral quantitative computed tomography to provide very good prediction of midshaft humerus mechanical properties with good short-term precision in human subjects was demonstrated. In study 3, collegiate-level jumping (long and/or high jump) athletes were shown to have larger side-to-side differences in tibial midshaft structure and estimated strength between their jump and lead legs than observed in non-jumping athletes. In study 4, prepubertal baseball players followed for 12 months were shown to gain more bone mass, structure and estimated strength in their throwing arm relative to their nonthrowing arm over the course of 12 months. These cumulative data using a combination of experimental models ranging from animal to cross-sectional and longitudinal human models demonstrate the ability of the skeleton to adapt its structure and estimated strength to the mechanical loading associated with exercise. Study of these models in future work may aid in optimizing skeletal responses to exercise.

<p>Allergic asthma is a disease involving airway inflammation, commonly linked to allergen exposure. Computed tomography (CT) is used to quantitatively assess changes in density, hence inflammation, in the lung. CT imaging provides the ability to non-invasively and longitudinally study disease progression and evaluate treatment efficacy. The objective of this study was to determine the sensitivity of CT to detect the anti-inflammatory effects of budesonide (BUD) by measuring airway tissue density in a rat model of allergic airway disease.</p> <p>Female<strong> </strong>Brown Norway rats were exposed intratracheally to house dust mite (HDM) extract (250 µg in 100µL saline) or saline control every other day for a total of five administrations (inflammatory phase). ABUD dose and temporal response study was performed usingBUD 0, 10, 100, and 300 µg/kg administered concurrently with HDM for three and six treatments (treatment phase). CT scanning was performed at baseline, post inflammatory phase, and after three and six BUD treatments. From the CT, density was measured in a defined volume of interest surrounding the major airways. Bronchoalveolar lavage (BAL) and histological samples were collected at the same time points.</p> <p>After the inflammatory phase, a significant increase in peribronchial density was found in the HDM group compared to controls. This corresponded to a significant increase in inflammation by histology andBALtotal cell count (TCC), specifically eosinophils. Within the treatment phase after three treatments,BUD100 and 300 µg/kg led to a significant shift in lung density compared to HDM exposure alone, to a state similar to baseline. All BUD treated groups expressed a significant reduction in peribronchial density after six treatments. However, histology andBALTCC only showed a significant decrease in inflammation after six treatments for all three BUD doses.</p> <p>CT densitometry is a sensitive, non-invasive method of evaluating the anti-inflammatory effects of budesonide and can be used for future screening of therapies in allergic lung models. Airway segmentation of CT permits the localized assessment of peribronchial inflammation, while other outcome measurements, such as BAL cytology, provide whole lung assessment which may not accurately reflect important regional changes.</p> / Master of Science (MSc)

Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill bit penetration and drill bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. This research demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the strength/quality of the bone. Drilling force does not give a direct measure of bone strength; therefore it has been correlated with the shear strength and screw pullout strength to determine the efficacy in estimating the bone strength. Various synthetic bone material densities and animal bones have been tested to demonstrate the use of drilling force data. A novel automated experimental test rig, which enables drilling tests, screw insertion and screw pullout tests to be carried out in a controlled environment, has been developed. Both drilling and screw pullout tests have been carried out in a single setting of the specimen to reduce the experimental errors and increase repeatability of the results. A significantly high value of correlation (r² > 0.99) between drilling force & shear strength and also between drilling force & normalised screw pullout strength in synthetic bone material was found. Furthermore, a high value of correlation (r² = 0.958 for pig bones and r² = 0.901 for lamb bones) between maximum drilling force & normalised screw pullout strength was also found. The result shows that drilling data can be used to predict material strength. Bone screws are extensively used during the internal fixation of fractured bones. The amount of screw been tightened is one of the main factor which affects the bone-screw fixation quality. Over tightening of screw can result into the loss of bone-screw fixation strength, whereas under tightening can result in the screw loosening. Therefore, optimum tightening of the screw is important to achieve the maximum bone-screw fixation strength. At present, optimum tightening of the screw is entirely dependent upon the skill and judgment of the surgeon, which is predominantly based on the feel of the screw tightening torque. Various studies have been reported in the literature to develop an algorithm to set an optimum tightening torque value to be used in surgery. A method which is based on the use of rotation angle of the screw while tightening, rather than using screw insertion/tightening torque, to optimise the bone-screw fixation strength is proposed in this research. The effectiveness of the proposed method has been successfully demonstrated on the synthetic bone material using the designed test rig. The optimum angle for the tested screw was found to be 120° which is equivalent to 33% of the screw pitch.

Foi comparada a massa óssea e a composição corporal dos hemicorpos dominante e não dominante de um grupo (A) de 16 pessoas com paralisia cerebral com hemiplegia espástica, e de um grupo (B) de 29 voluntários normais por meio da mensuração da massa corporal, estatura e densitometria óssea do corpo total com composição corporal. Foi encontrada diferença estatística significante no conteúdo mineral ósseo dos membros superiores do grupo A e dos membros superiores e inferiores, tronco e total do grupo B; na massa magra dos membros inferiores do grupo A e dos membros superiores e inferiores, tronco e total do grupo B; na massa adiposa dos membros inferiores do grupo A e dos membros superiores e inferiores, tronco e total do grupo B; e no conteúdo mineral ósseo dos membros superiores e inferiores, e total e na massa magra dos membros superiores e inferiores entre os hemicorpos não dominantes dos grupos A e B. Foi encontrada também correlação estatística significante entre o conteúdo mineral ósseo e a massa magra nos grupos A e B em todos os sítios, exceto no tronco dominante do grupo A; e o conteúdo mineral ósseo e a massa corpórea no tronco dominante do grupo A e no membro inferior dominante e bilateral do grupo B / Were compared the bone mass and body composition of the dominant and nondominant hemi bodies in a group (A) of a 16 spastic hemiplegic cerebral palsy and in a group (B) of 27 normal volunteers by weight, height, and densitometry of total body with body composition measure. Were observed significant statistical difference in the bone content mineral of the upper limbs of the group A and of the upper and lower limbs, trunk and total of the group B; in the lean mass of the lower limbs of the group A and of the upper and lower limbs, trunk and total of the group B; in the mass fat of the lower limbs of the group A and of the upper and lower limbs, trunk and total of the group B; and in the bone mineral content of the upper and lower limbs, and total, and in the lean mass of the upper and lower limbs between the hemi bodies no dominant of the A and B groups. Were observed too statistical correlation between the bone mineral content and lean mass in the groups A and B in all locals, except in the trunk of group A; and between the bone mineral content and body mass in the trunk of group A and lower limb dominant and bilateral of group B

As árvores de Tectona grandis (Verbenaceae) e de Pinus caribaea var. hondurensis (Pinaceae) são utilizadas em estudos dendroecológicos e dendroclimatológicos pela formação de anéis de crescimento anuais duas espécies plantadas na Mata da Pedreira do Campus da ESALQ/USP para estudos ecológicos e climáticos. Foram selecionadas 8 árvores de Tectona grandis (4 com e 4 sem lianas ocupando a copa das árvores) e 10 árvores de Pinus caribaea var. hondurensis (8 vivas - 4 com e 4 sem lianas ocupando a copa das árvores - e 2 mortas). Com a utilização de sondas de Pressler foram extraídas 2-6 amostras do lenho/árvore das 2 espécies para analisar seus anéis de crecimiento. Foi realizada (i) a caracterização anatômica macro e microscópica dos anéis de crescimento; (ii) estudos de dendrocronologia, pela datação e avaliação do crescimento radial do tronco das árvores; (iii) avaliação da densidade do lenho por densitometria de raios X para a determinação da densidade dos anéis de crescimento, incremento de biomassa e de carbono; (iv) avaliação da influência do clima local e em grande escala no crescimento do tronco das árvores; (v) análise dos vasos das árvores de T. grandis e dos anéis de crescimento falsos nas árvores de P. caribaea. Os resultados principais mostraram que as características anatômicas dos anéis de crescimento das árvores as 2 espécies coincidem com os descritos na literatura; a série de anéis de crescimento mostrou correlação significativa em relação à sincronização dos anéis de crescimento das árvores das 2 espécies. O efeito prejudicial das lianas na copa das árvores de T. grandis e de P. caribaea foi comprovado pela redução da largura dos anéis de crescimento no período de 2000-11 e de 1971-2011, respectivamente. A densidade aparente média dos anéis de crescimento (T. grandis: 0,64 g/cm3 e de P. caribaea: 0,60 g/cm3) permitiu calcular o incremento de massa de carbono, resultando que as árvores sem lianas apresentam maior estoque de carbono do que as com lianas. A análise dendroclimatológica mostrou que as árvores de P. caribaea apresentaram correlações positivas com a disponibilidade de água no solo no período de seca; as árvores de T. grandis mostram correlação positiva com o período de maior chuva, temperatura de primavera e a oscilação antártica (AAO) de outono no ano corrente de crescimento, e correlação negativa com o evento de El Niño (TNI) em outono anterior. A ocupação das lianas na copa das árvores de T. grandis provocou o aumento da área dos vasos; os vasos do lenho inicial (e sua frequência) mostraram correlação significativa com a largura dos anéis de crescimento, possibilitando a construção de cronologias desses parâmetros e a avaliação da influência climática nas árvores. A ocupação das lianas na copa das árvores de P. caribaea induziu diminuição da frequência dos anéis de crescimento falsos, formados, principalmente, pelo aumento das pricipatações de Julio anterior y verão (DJF) e corrente. Os resultados deste estudo permitiram concluir que a análise dos anéis de crescimento das árvores das 2 espécies tem grande potencial para estudos ecológicos e ambientais no Brasil. / The trees of Tectona grandis (Verbenaceae) and Pinus caribaea var. hondurensis (Pinaceae) are used in dendroecological and dendroclimatologal studies by formation the annual growth rings. For these reasons, the study aimed to examine the tree-rings of the two species planted in Mata da Pedreira in Campus ESALQ/USP to climatic and ecological studies. We selected eight T. grandis trees (4 with and 4 without lianas occupying the trees canopy) and 10 P. caribaea trees (8 live - 4 with and 4 without lianas- and 2 dead). With the use Pressler increment borer was extracted 2-6 wood samples/tree of two species to analyze their trees-rings growth. Were applied: i) anatomical characterization macro and microscopic of trees-rings; ii) dendrochronology studies, by dating and evaluation of the trees radial growth; iii) evaluating the density of the wood by X-ray densitometry for determination of tree-rings density, biomass and carbon increment; iv) evaluating of influence of local climate and large-scale on tree-rings; v) Analysis of the vessel in T. grandis trees and false rings in P.caribaea trees. The main results showed that the anatomical characteristics of trees-rings of the both species coincide with those described in the literature; the series of trees-rings showed significant correlation with respect to the synchronization of trees-rings in the two species. The unfavorable effect of lianas in the canopy of trees T. grandis and P. caribaea was confirmed by the reduction of the tree-rings width in period 2000-2011 and 1976-2011, respectively. . The apparent density average of tree-rings (T. grandis: 0,64 g/cm3 e de P. caribaea: 0,60 g/cm3) allowed us to calculate the increase of carbon mass, resulting that trees without lianas had higher carbon stocks than those with lianas. The climatological analysis showed that P. caribaea showed positive correlations with water availability in the soil in the dry season; T. grandis trees showed positive correlations with period of highest rainfall, temperature of spring and AAO of fall in the current growing season, and negative correlation with El Niño event (TNI) in the fall. The ocupation of lianas on T. grandis trees caused the increase of the vessels area; the earlywood vessels (and frequency) had a significant correlation with the tree-rings, allowing build of chronologies of these parameters and evaluate the influences climate in the trees. The ocupation of lianas on P. caribaea trees induced a decrease in false rings, which are formed primarily by the increase of the previous July and current summer (DJF). The results of this study showed that the tree-rings analysis of the two species has great potential to ecological and climatical studies in Brazil.

Os objetivos do presente trabalho foram: avaliar o processo de biodeterioração do lenho das árvores de tipuana na cidade de São Paulo e relacionar as alterações da sua estrutura anatômica e propriedades físico-mecânicas com o seu risco de queda. Nos passeios públicos de regiões selecionadas da cidade, 1109 árvores de tipuana foram caracterizadas quanto às condições de entorno, estado geral, variáveis dendrométricas, biodeterioração externa e interna e o risco de queda, estimado com modelo de cálculo estrutural desenvolvido pelo IPT. A biodeterioração e os mecanismos de resistência das árvores foram avaliados ao nível macroscópico e microscópico. As alterações nas propriedades do lenho de tipuana foram analisadas por densitometria de raios X e pelos ensaios físico-mecânicos (densidade de massa aparente; resistência à flexão) e aplicado o método de elementos finitos para análise da distribuição de tensões no lenho. As árvores de tipuana de elevada idade não apresentaram sinais de declínio, embora com estado geral considerado como crítico, pelo plantio em locais indequados, manejo inapropriado e/ou ocorrência de injúrias. O lenho foi deteriorado por fungos apodrecedores, cupins-subterrâneos e brocas-de-madeira, sendo os fungos e cupins os principais organismos xilófagos, afetando a região do cerne; a associção entre os fungos, os cupins, as variáveis dendrométricas e o risco de queda foram estatisticamente significantes ao nível de 5 %. O cupim-subterrâneo Coptotermes gestroi ocorreu em elevados níveis de infestação nas árvores, sendo considerado, no entanto, como um organismo-praga secundário, fortemente associado com lenho previamente apodrecido por Ganoderma sp.. Os fungos apodrecedores ocorrentes foram classificados como de podridão branca e mole, sendo a primeira mais comum no cerne das árvores. Como mecanismo de resistência à biodeterioração observou-se a compartimentalização do lenho, caracterizada pelo acúmulo de extrativos nas células. Os fungos xilófagos causaram reduções significativas na densidade de massa aparente, tensão de ruptura à flexão estática e módulo de elasticidade em estágios incipiente e intenso de apodrecimento do lenho. Ruptura do tronco e o risco de queda das árvores de tipuana relacionaram-se, principalmente, com a intensidade da deterioração do lenho e com a sua dendrometria. A alteração da distribuição das tensões no lenho foi analisada em relação ao estágio, tamanho e localização da deterioração no tronco das árvores de tipuana. / The objectives of the present work were to evaluate the process of biodeterioration in the wood of tipuana trees in the city of São Paulo and to relate the alterations in the anatomical structures and physical and mechanical properties with there falling risk. In the sidewalks of selected regions of the city, 1109 trees were characterized taking into consideration aspects as surroundings, general conditions, dendrometric variables, external and internal biodeterioration and falling risk estimated by using a structural model developed by IPT. The biodeterioration and the resistance mechanisms of the trees were evaluated at a macro and microscopic levels. The alterations on the wood properties were analysed by X-rays densitometry and by performing physical and mechanical tests (specific gravity; bending resistance); the tension distribution in the wood was analyze by finite-elements method. The old aged trees encountered, did not show any sign of decline, eventhough, the general aspect of their surroundings was critical by the inadequate places they were planted; inappropriate management and/or occurrence of injuries. The trees had their trunks deteriorated by xylophagous organisms, mainly fungi and subterranean-termites, and some wood borer beetle too, which affected the heartwood. The association between the presence of the first two organinsms, the dendrometric variables and the risk of falling, was statistically significant at the 5% level. The infestation of the trees by the subterranean-termite Coptotermes gestroi was at high levels, however, it was considered as a secundary plague-organism, because its attack was strongly associated with the previously decayed heartwood by Ganoderma sp.. The decaying fungi observed were classified as white rot and soft rot, being the white rot more common in the heartwood of the trees. As a resistance mechanism of the trees against biodeterioration, it was observed the compartimentalization of the wood characterized by the accumulation of extractives in the cells. Decaying fungi caused significant reductions in the following wood properties: specific gravity, rupture strength to bending and modulus of elasticity either in incipient or intense decay. Trees trunk rupture and falling risk were associated mainly to biodeterioration intensity and dendrometric variables. The alteration of tension distribution in the wood was analyzed in relation to the stage, size and position of the deterioration in the wood of the trees.

O estado do Acre possui uma vocação eminentemente florestal, devido a alta abundância natural de espécies madeireiras em um ecossistema caracterizado pela biodiversidade de espécies tropicais. Pesquisas em dendrocronologia nessa região tropical indicam que 35-50% das espécies arbóreas formam anéis de crescimento. Neste sentido, a dendrocronologia, método baseado na análise de anéis de crescimento anuais no lenho, torna-se importante ferramenta, fornecendo dados de longos períodos de crescimento e estimativas acuradas da idade das árvores, para o entendimento da dinâmica da floresta e desenvolvimento de sistemas de manejo florestal sustentados. Portanto, o objetivo dessa pesquisa foi o de estudar três espécies arbóreas de ocorrência natural no Acre, verificar a influência da quantidade total e distribuição sazonal de pluviosidade, temperatura e evapotranspiração, e os aspectos fenológicos apresentados por cada espécie, no seu crescimento em diâmetro e na qualidade do lenho produzido. O estudo foi realizado em três diferentes sítios, sendo que na Reserva Experimental Catuaba, havia três diferentes microsítios: floresta primária, borda de floresta e pastagem. Avaliou-se mensalmente o incremento em circunferência do tronco das árvores com dendrômetros e a fenologia com observações visuais das árvores das espécies selecionadas. Foram retiradas amostras de lenho no DAP do tronco para as avaliações dendrocronológicas, de densitometria de raios X e anatômicas do lenho. Verificou-se que a fenologia das árvores das espécies estudadas é regulada pela precipitação no mês corrente ou dos meses anteriores. Observou-se que a formação dos anéis de crescimento das árvores dessas espécies é regulada pela evapotranspiração, e pelas fenofases de queda e brotação de folhas nas diferentes estações sazonais do ano, indicando que possuem potencial para estudos paleoclimáticos. A análise da densitometria de raios X e anatômica do lenho mostrou ser possível separar seções de lenho juvenil e adulto no sentido radial do tronco das árvores. Houve diferença significativa no ritmo de crescimento do tronco das árvores entre as espécies, sítios e microsítios. Há grande potencial do uso da dendrocronologia aliada ao uso de parcelas de inventário permanente para a definição do ciclo de corte das árvores dessas espécies / The state of Acre has an eminently forest asset due the high natural timber species abundance in an ecosystem characterized by the biodiversity of tree tropical species. Researches in dendrochronology in this tropical region indicate that 35-50% of species form tree rings. Therefore, dendrochronology, a method based on tree ring analysis becomes important tool, providing data for long growth periods and accurate estimates of trees age, to understanding the forest dynamics and the development of sustainable forestry management. Thus, the objective of this research was to study some tree species of natural occurrence in Acre, verify influence of total amount and seasonal distribution of rainfall, temperature and evapotranspiration, and phenological aspects presented by each species in their growth in diameter and quality of timber produced. The study was conducted at three different sites, and in the Catuaba Experimental Reserve in three different microsites: primary forest, pasture and forest edge.The increase in the circumference the trunk was assessed monthly with a dendrometer and phenology was evaluated with visual observations in selected tree species. Samples were collected from wood in the DBH of the trunk for dendrochronological, X-ray densitometry and wood anatomy assessments. It was found that the phenology of the trees species is regulated by rainfall in the current month or previous months. It was observed that the formation of growth rings of trees of these species is regulated by evapotranspiration, and by phenophases of fall and sprouting new leaf during the year, indicating that these species have potential for paleoclimate studies. The analysis of Xray densitometry and anatomical of the wood allowed to separate portions of the juvenile and adult wood in radial section of the trunk. There were significant differences in the growth of the trunk of tress between species, sites and microsites. There is great potential for the use of dendrochronology combined with the use of permanent inventory plots to define cutting cycles for these species.