Including porosity introduces absorption into the previously developed scattering analysis for elastic spheres. Acoustic propagation in porous media has two distinct compressional modes, one in which the fluid and the structure move in phase with each other and the other in which they move in opposite phase. Expressions for the complex wavenumbers of both waves are derived, using the parameters for manganese nodules. A modal analysis with a pressure boundary condition indicates that the first kind of compressional wave is lightly attenuated and carries most of the energy of the coupled system. The second compressional wave is highly attenuated and effectively loses all of its energy in the first centimeter of the nodule. This second wave is very important for consideration of nodule-scale dimensions since it represents the dominant loss mechanism. A method was developed to form a single effective compressional wave attenuation for both compressional waves by employing a pressure and velocity boundary condition at the surface of the nodule and using a spatially integrated intensity match. An effective wave attenuation is generated for the compressional wave in the non-porous elastic model which accounts for porous attenuation and which is based on a parameter defined as travel distance L. If L is assumed to be proportional to nodule radius, the attenuation is approximated as constant for the frequency range of interest and is independent of nodule radius. An effective attenuation is predicted. The shear attenuation is found to exhibit a frequency squared form dependence for manganese nodules. However, shear attenuation is very small for ideal nodules and is negligible compared to the compressional loss. The elastic model of the nodule was numerically altered to accommodate complex wavenumbers in shear and compression. Four distinct regions of attenuation are observed in individual reflectivity, R_θ, versus ka plots and discussed. The importance of including attenuation is readily apparent from observing the transformation of the elastic non-porous results. Scattering experiments were performed on manganese nodules and experimental individual reflectivity versus ka plots were generated. Good agreement is found for the spherical Atlantic nodules using values in the third region of attenuation. From these experiments, an estimation of attenuation is made and compared with the theoretical prediction. The influence of attenuation on individual scattering and multiple scattering is investigated. Attenuation tends to shift the major bottom reflectivity, C_R, peak toward lower ka values. This affects the prediction of the acoustic response of manganese nodule deposits. / Master of Science

Soil samples from different locations with varied soybean cultivation histories were taken from arable fields in 2018 in East Germany and Poland (Lower Silesia) to evaluate the specific microsymbionts of the soybean, Bradyrhizobium japonicum, one to seven years after inoculation. Soybeans were grown in the selected farms between 2011 and 2017. The aim of the experiment was to investigate whether there is a difference in rhizobia contents in soils in which soybeans have been recultivated after one to seven years break, and whether this could lead to differences in soybean plant growth. The obtained soil samples were directly transferred into containers, then sterilized soybean seeds were sown into pots in the greenhouse. After 94 days of growth, the plants were harvested and various parameters such as the nodular mass, number of nodules, and dry matter in the individual plant parts were determined. In addition, the relative abundances of Bradyrhizobium sp. in soil samples were identified by sequencing. No major decline in Bradyrhizobium sp. concentration could be observed due to a longer interruption of soybean cultivation. Soil properties such as pH, P, and Mg contents did not show a significant influence on the nodule mass or number, but seem to have an influence on the relative abundance of Bradyrhizobium sp. The investigations have shown that Bradyrhizobium japonicum persists in arable soils even under Central European site conditions and enters into an effective symbiosis with soybeans for up to seven years.:Introduction Materials and Methods Results Discussion Supplementary Materials Author Contributions Funding Acknowledgments Conflicts of Interest References

Einleitung: Der frühzeitigen Detektion pulmonaler Rundherde kommt eine Schlüsselrolle bei neoplastischen Erkrankungen von Hund und Katze zu, indem sie maßgeblich Prognose und Behandlungsoptionen beeinflusst. Ziel unserer ersten Studie war, die aktuelle diagnostische Wertigkeit und mögliche Limitationen der klassischen Röntgenuntersuchung bei der Detektion pulmonaler Rundherde darzustellen. Unsere zweite Untersuchung beschäftigt sich mit dem Ziel der computerassistierten Detektion (CAD) und deren Einsatz in der Tiermedizin. Material und Methoden: Der Untersuchungszeitraum umfasste die Jahre 2005–2011. In die erste Studie wurden Hunde und Katzen mit pulmonalen Rundherden aufgenommen, an denen zunächst eine klassische Röntgenuntersuchung und anschließend innerhalb von 14 Tagen eine computertomographische Untersuchung (CT) durchgeführt wurde. Neben der Darstellung möglicher Limitationen der klassischen Röntgenuntersuchung wurde auch deren Sensitivität hinsichtlich des Vorliegens pulmonaler Rundherde im Vergleich zur CT als Goldstandard untersucht. Gemäß den Einschlusskriterien wurden 50 Hunde und 20 Katzen in die erste Studie aufgenommen. Die zweite Untersuchung beschäftigt sich mit der Sensitivität eines computerassistierten Detektionssystems sowie dessen möglichen Mehrgewinns für den Radiologen bei der Detektion pulmonaler Rundherde in der Tiermedizin. Darüber hinaus wurden die möglichen Limitationen eines solchen Systems untersucht. In die Untersuchung wurden nicht nur Tiere mit Rundherden eingeschlossen, sondern auch solche mit Massen (Herde größer 3 cm). Ausgeschlossen waren Patienten mit mehr als 50 Rundherden pro Lungenhälfte sowie Rundherde/Massen, die vollständig in Atelektasen eingebettet waren. Gemäß den Einschlusskriterien wurden bei 51 Hunden und 16 Katzen insgesamt 586 Rundherde als Referenzwert für die CAD zugrunde gelegt. Ergebnisse: Als ein Ergebnis aus der vorliegenden ersten Studie zeigt sich für die Projektionsradiographie eine Detektionsrate von insgesamt 61 % (64 % für Hunde und 55 % für Katzen) verglichen mit der CT als Goldstandard. Gründe für eine fehlende Detektion liegen vor allem darin, dass die Röntgenuntersuchung im Ergebnis ein Summationsbild liefert. Daneben spielt auch die Rundherdgröße eine (untergeordnete) Rolle. Das in der zweiten Studie eingesetzte Detektionssystem zur computerassistierten Detektion pulmonaler Rundherde wies für die Tiermedizin eine Sensitivität von 69,4 % auf. Gleichzeitig wurde eine hohe Anzahl falsch positiver sowie falsch negativer Befunde durch die CAD verzeichnet. Dennoch ließ sich durch den Einsatz der CAD die Sensitivität von Untersucher 1 von 89,2 % auf 94,7 % steigern, die von Untersucher 2 von 87,4 % auf 90,8 %. Schlussfolgerungen: Aufgrund der engen Einschlusskriterien dieser Studie kann für die Detektion pulmonaler Rundherde in der Projektionsradiographie als Mindestwert die hier ermittelte durchschnittliche Sensitivität von 61 % zugrunde gelegt werden. Die klassische Röntgenuntersuchung eignet sich weiterhin als erstes bildgebendes Verfahren für die pulmonale Rundherddetektion, für ein genaues Staging sollte allerdings die CT angewandt werden. Für eine fehlende Rundherddetektion war nicht primär die geringe Größe der Rundherde ursächlich, sondern vielmehr Begleiterkrankungen, die mit einer Transparenzminderung der Lunge einhergingen. Daher sollte insbesondere dann die CT zum Einsatz kommen, wenn zusätzliche Veränderungen wie beispielsweise ein Pleuraerguss vorliegen. Für die Detektion pulmonaler Rundherde in der CT-Untersuchung gilt, dass die Sensitivität des Radiologen grundsätzlich durch ein automatisches Detektionssystem gesteigert werden kann. Somit eignet es sich insbesondere dann, wenn kein zweiter radiologischer Befunder vorhanden ist. Allerdings weist die CAD eine sehr hohe Anzahl falsch positiver sowie einige falsch negative Befunde auf, so dass sich für ihren routinemäßigen Einsatz in der Tiermedizin derzeit noch Limitationen ergeben. / Introduction: The early detection of pulmonary nodules plays a key role in neoplastic conditions of dogs and cats substantially influencing prognosis and therapy options. The aim of our first study was to outline the actual diagnostic value as well as the potential limitations of projection radiography for detection of pulmonary nodules. Our second study addresses the newer aspect of computer assisted detection (CAD) and its possible application in veterinary medicine. Materials and methods: The investigation period was between 2005 and 2011. In our first study we included those dogs and cats with pulmonary nodules that underwent a radiographic examination as well as a computed tomographic examination (CT) within a period of 14 days. Aside from the description of possible limitations of projection radiography, we also evaluated its sensitivity for detection of pulmonary nodules compared to CT as gold standard. According to the inclusion criteria 50 dogs and 20 cats were admitted to this study. The second study dealt with the sensitivity of a computer assisted detection system and its potential benefit for radiologists for the detection of pulmonary nodules in veterinary medicine. Furthermore, we outlined possible limitations of the detection system. This study not only comprised dogs and cats with pulmonary nodules, but also those with pulmonary masses (i.e. nodules > 3 cm). We excluded patients with more than 50 nodules either in the right or the left lung as well as nodules/masses embedded in a massive atelectasis. According to our inclusion criteria, we determined 586 nodules in total, distributed on 51 dogs and 16 cats used as reference value for the CAD. Results: As one result of our first study, we found a detection rate of 61 % (64 % for dogs and 55 % for cats) for projection radiography in comparison to CT as gold standard. Reasons for a missing detection of pulmonary nodules are predominantly limitations that come along with superimpositions using projection radiography; apart from that, nodule size is of some subsidiary meaning. The detection system for the computer assisted detection of pulmonary nodules used in the second study showed a sensitivity of 69.4 % in veterinary medicine. Additionally a high number of false positive findings as well as false negative findings was detected by CAD. However, due to the use of CAD the sensitivity of examiner 1 increased from 89.2 % to 94.7 %, the sensitivity of examiner 2 increased from 87.4 % to 90.8 %. Conclusions: Based on the strict inclusion criterion in this study the average sensitivity of 61 % can be used as a minimum for the detection of pulmonary nodules using radiographs. Projection radiography is suitable as first line diagnostic tool for the detection of pulmonary nodules. For accurate tumor staging CT should be used. Since predominant reasons for a missing detection of pulmonary nodules consisted of limitations that come along with superimpositions (like pleural effusion) CT is especially recommended in those cases. In general, the sensitivity of radiologists can be improved by an automatic detection system concerning the detection of pulmonary nodules using CT. Especially in those cases, when no second reader is available, CAD is suitable. However, the CAD system we used herein yielded a high number of false positive findings as well as false negative findings; therefore, its use in veterinary medicine on a routine basis still has some limitations.

Raramente plantações de eucalipto respondem à adubação nitrogenada. Contudo, por se tratar de povoamentos monoespecíficos, com baixa capacidade de fixação de N, depois de algumas rotações de cultivo a probabilidade de resposta a este nutriente aumenta, devido ao esgotamento das reservas naturais de nitrogênio do solo acumuladas no ecossistema anterior. O presente estudo teve como objetivos avaliar i) o crescimento, o desenvolvimento de raízes finas de Eucalyptus grandis e de Acacia mangium em povoamentos monoespecíficos e mistos; ii) a nodulação da A. mangium nestes povoamentos. As árvores foram plantadas em maio de 2003 no espaçamento 3m x 3m. O delineamento experimental foi o de blocos completamente aleatorizados (4 blocos), sendo avaliados 3 tratamentos: povoamentos monoespecíficos de E. grandis e A. mangium e um povoamento em que essas espécies foram consorciadas (1100 plantas por ha de E. grandis e 550 árvores por ha de A. mangium). Quando consorciada, a A. mangium foi plantada no meio da distância entre as árvores de E. grandis na mesma linha de plantio. Foram amostradas raízes finas vivas (≤3 mm) em 5-16 posições (dependendo do tratamento), de uma árvore de área basal média em doze parcelas (3 tratamentos x 4 blocos), até 1 m de profundidade aos 6 e 12 meses pós-plantio e até 2 m de profundidade aos 18 e 30 meses pós-plantio, por meio de uma sonda de aço com 4,5 cm de diâmetro interno. O E. grandis foi diferente da A. mangium quanto ao desenvolvimento radicular nos diferentes períodos de amostragem, principalmente na camada superficial do solo (0-10 cm). No povoamento misto, aos 30 meses pós-plantio, o E. grandis foi 64% maior em altura do que a A. mangium e 75% maior em área basal, produzindo 94% mais biomassa do que esta leguminosa. A assimetria do crescimento radicular foi elevada entre as espécies, reflexo da grande competição por luz na parte aérea. Não houve clara estratificação de exploração das camadas do solo pelo sistema radicular das espécies. O E. grandis apresentou maior exploração radicular em todas as camadas do solo, fazendo com que o desenvolvimento radicular da A. mangium ficasse restrito a proximidade da árvore. O elevado grau de assimetria no desenvolvimento radicular entre as espécies resultou, aos 30 meses, na camada 0-10 cm, numa diferença de 91% na densidade de raízes finas (drf) entre as espécies. A nodulação foi sensível a competição com o E. grandis, aparentemente, devido à variação de umidade e temperatura sazonal. Aos 18 meses, no povoamento monoespecífico, houve tendência de maior densidade de nódulos na linha de plantio, camada 0-10 cm. Aos 30 meses os nódulos foram encontrados próximos às árvores. No misto, aos 18 e 30 meses ocorreu diminuição da densidade de nódulos na camada 10-30 cm e aumento entre 30 e 50 cm. / Eucalypts plantations rarely answer to the nitrogen fertlization. However, for being of monospecific stands, with low capacity of N fixation, after some cultivation rotations the answer probability to this nutritious one increases, due to the exhaustion of the natural reservations nitrogen of the soil accumulated in previous ecosystem. The present study had as objectives to evaluate i) the growth, the development of Eucalyptus grandis and Acacia mangium fine-root in monospecific and mixed stands; ii) the A. mangium nodulation in these stands. The trees were planted in may of 2003 in the spacing 3m x 3m. The experimental design was it of completely randomized blocks (4 blocks), between assessed 3 treatments: Monospecific stands of E. grandis and A. mangium and a stand in that those species were mixed (1100 plants for ha of E. grandis and 550 trees for ha of A. mangium). When mixed, to A. mangium was planted in the middle of the distance among the trees of E. grandis in the same plantation line. They were sampling live fine-root (≤ 3 mm) in 5-16 positions (depending on the treatment), of a tree of medium basal area in twelve portions (3 treatments x 4 blocks), until 1 m of depth to the 6 and 12 months powder-plantation and until 2 m of depth to the 18 and 30 months powder-plantation, by means of a sledgehammer with 4,5 cm of internal diameter. The E. grandis was different from the A. magium with relationship to the roots development in the different sampling periods, mainly in the superficial layer of the soil (0-10 cm). In the mixed stand, between 29 and 30 months after plantation, E. grandis was 64% larger in height than at A. mangium and 75% larger in basal area, producing 94% more biomass than this leguminous. The asymmetry of the root growth was elevated between the species, reflex of the great competition for light in the aerial part. There was not clear stratification of exploration of the layers of the soil for the roots system of the species. The E. grandis presented larger roots exploration radicular in all the layers of the soil, doing with that the roots development of the A. mangium was restricted in the proximity of the tree. The high asymmetry degree in the roots development between the species, resulted to the 30 months in the layer 0-10 cm, a difference of 91% in the density of fine roots (dfr) between the species. The nodulation was sensitive the competition with the E. grandis , seemingly, due to the humidity variation and seasonal temperature. To the 18 months, in the monospecific stands, there was tendency of larger density of nodules in the plantation line, layer 0-10 cm. To the 30 months the nodules were found close to the trees. In the mixed, to the 18 and 30 months it happened decrease of the density of nodules in the layer 10-30 cm and increase between 30 and 50 cm.

O Pantanal é a maior planície continental inundável do mundo, englobando um mosaico de diferentes habitats, sustentando grande diversidade vegetal, animal e de solos. É constituído por onze sub-regiões, sendo uma delas a do Pantanal de Barão de Melgaço, que está localizado ao nordeste dessa bacia sedimentar quaternária. Apresenta uma heterogeneidade espacial de solos que está relacionada com a diversidade de feições geomórficas. Estas, adicionadas aos tipos de inundação, geram uma grande diversidade de microhabitats: Cordilheiras, Paleodiques, Murunduns, constituem as formas de relevo raramente inundáveis, enquanto que as Planícies fluviais, Campos, Baías, Corixos e Vazantes apresentam inundações anuais ou permanentes. No Pantanal de Barão de Melgaço, as altitudes variam de 100 a 150m e a declividade é inexpressiva. O material de origem dos solos é formado por sedimentos arenosos, síltico-arenosos, argilo-arenosos e arenoconglomeráticos semiconsolidados a consolidados a Formação Pantanal. Contém uma diversidade única de solos, freqüentemente com mineralogia 2:1, cuja morfologia reflete as condições de regime hídrico de cada microambiente: Planossolos, Plintossolos, Planossolos Nátricos, Vertissolos e Neossolos Flúvicos se distribuem de acordo com as feições geomórficas encontradas, sendo na grande maioria afetados por processos redoximórficos. O objetivo desta dissertação foi caracterizar e conhecer os processos pedogenéticos dos solos de um sistema pedológico Planossolo-Plintossolo em duas das principais feições geomórficas do Pantanal de Barão de Melgaço. O estudo foi realizado na RPPN (Reserva Particular do Patrimônio Natural) SESC Pantanal, no município de Barão de Melgaço, Estado de Mato Grosso. No sistema pedológico estudado foram identificados quatro solos da classe dos Plintossolos Argilúvicos e Háplico e dois Planossolos Nátricos. A transição dos Planossolos Nátricos para os Plintossolos é evidencia a pela perda gradual do caráter sódico e aumento do processo de plintização. À medida que ocorre a redução da saturação por Na+, a CTC dos solos torna-se saturada por Al3+. A presença de solos com caráter sódico ou nátrico nas partes altas da paisagem, pode ser uma evidência das mudanças climáticas que ocorreram no Pantanal, neste caso tratando-se de solos reliquiais. As principais causas da manutenção dos altos teores de Na nos Planossolos Nátricos, são a porosidade muito fechada dos horizontes subsuperficiais e as elevadas taxas de evapotranspiração no Pantanal, mesmo ocorrendo em posição mais elevada na paisagem local. Os Nódulos de Fe e Mn que ocorrem nesses solos não são pedorelíquias. Foram formados e continuam se formando em condições climáticas atuais. / The Pantanal is the largest continental flood plains, comprising a mosaic of different habitats, maintaining plant diversity, animal and soil. It consists of eleven sub-regions, one of which the of the Pantanal of Barão de Melgaço, which is located north of the Quaternary sedimentary basin. It presents a spatial heterogeneity that is related to the diversity of geomorphic features. This, added to the types of flooding and soil, generate a wide variety of microhabitats: Cordileira paleoriverbanks, termite hills, the forms of relief are rarely flooded, while the Plains river, Grasslands, Bays, Corixo and present ebb Annual floods or permanent. In the Pantanal of Barão de Melgaço, the above sea level ranging from 100 to 150m and the slope is negligible. The parent material of the soil is composed of sandy sediment, síltico-sand, clay-sandy and sandyconglomerate semiconsolidados the consolidated Training Pantanal. It contains a unique diversity of soils, often with 2:1 mineralogy, whose morphology reflects the conditions of water regime of each microenvironment: Planosols, Plinthosols, Solonetz, Vertisols and Fluvisols are distributed according to the geomorphic features found, and the great most affected by processes redoximorphic. The goal of this dissertation was to characterize and identify the processes pedogenetic soil of a system pedological Solonetz-Plinthosol in two of the main geomorphic features of the Pantanal of Barão de Melgaço. The study was conducted in RPPN (Private Reserve of Natural Heritage) SESC Pantanal, in the Barão de Melgaço county, State of Mato Grosso from Brazil. The transition of Solonetz for Plinthosol is given by the gradual loss of sodium and increase character of the plintização. As is the reduction of the saturation of Na+, the CEC soil becomes saturated by Al3+. The presence of soil character natric in the hillslope is an evidence of climate changes that occurred in the Pantanal, where the soils relic. The main causes of maintenance of high levels of Na in Solonetz are very closed the porosity of subsurface horizons and high rates of evapotranspiration in the Pantanal. The nodules of Fe and Mn that occur in these soils are not relic and were formed and are still forming in weather conditions to actually.

O Pantanal é a maior planície continental inundável do mundo, englobando um mosaico de diferentes habitats, sustentando grande diversidade vegetal, animal e de solos. É constituído por onze sub-regiões, sendo uma delas a do Pantanal de Barão de Melgaço, que está localizado ao nordeste dessa bacia sedimentar quaternária. Apresenta uma heterogeneidade espacial de solos que está relacionada com a diversidade de feições geomórficas. Estas, adicionadas aos tipos de inundação, geram uma grande diversidade de microhabitats: Cordilheiras, Paleodiques, Murunduns, constituem as formas de relevo raramente inundáveis, enquanto que as Planícies fluviais, Campos, Baías, Corixos e Vazantes apresentam inundações anuais ou permanentes. No Pantanal de Barão de Melgaço, as altitudes variam de 100 a 150m e a declividade é inexpressiva. O material de origem dos solos é formado por sedimentos arenosos, síltico-arenosos, argilo-arenosos e arenoconglomeráticos semiconsolidados a consolidados a Formação Pantanal. Contém uma diversidade única de solos, freqüentemente com mineralogia 2:1, cuja morfologia reflete as condições de regime hídrico de cada microambiente: Planossolos, Plintossolos, Planossolos Nátricos, Vertissolos e Neossolos Flúvicos se distribuem de acordo com as feições geomórficas encontradas, sendo na grande maioria afetados por processos redoximórficos. O objetivo desta dissertação foi caracterizar e conhecer os processos pedogenéticos dos solos de um sistema pedológico Planossolo-Plintossolo em duas das principais feições geomórficas do Pantanal de Barão de Melgaço. O estudo foi realizado na RPPN (Reserva Particular do Patrimônio Natural) SESC Pantanal, no município de Barão de Melgaço, Estado de Mato Grosso. No sistema pedológico estudado foram identificados quatro solos da classe dos Plintossolos Argilúvicos e Háplico e dois Planossolos Nátricos. A transição dos Planossolos Nátricos para os Plintossolos é evidencia a pela perda gradual do caráter sódico e aumento do processo de plintização. À medida que ocorre a redução da saturação por Na+, a CTC dos solos torna-se saturada por Al3+. A presença de solos com caráter sódico ou nátrico nas partes altas da paisagem, pode ser uma evidência das mudanças climáticas que ocorreram no Pantanal, neste caso tratando-se de solos reliquiais. As principais causas da manutenção dos altos teores de Na nos Planossolos Nátricos, são a porosidade muito fechada dos horizontes subsuperficiais e as elevadas taxas de evapotranspiração no Pantanal, mesmo ocorrendo em posição mais elevada na paisagem local. Os Nódulos de Fe e Mn que ocorrem nesses solos não são pedorelíquias. Foram formados e continuam se formando em condições climáticas atuais. / The Pantanal is the largest continental flood plains, comprising a mosaic of different habitats, maintaining plant diversity, animal and soil. It consists of eleven sub-regions, one of which the of the Pantanal of Barão de Melgaço, which is located north of the Quaternary sedimentary basin. It presents a spatial heterogeneity that is related to the diversity of geomorphic features. This, added to the types of flooding and soil, generate a wide variety of microhabitats: Cordileira paleoriverbanks, termite hills, the forms of relief are rarely flooded, while the Plains river, Grasslands, Bays, Corixo and present ebb Annual floods or permanent. In the Pantanal of Barão de Melgaço, the above sea level ranging from 100 to 150m and the slope is negligible. The parent material of the soil is composed of sandy sediment, síltico-sand, clay-sandy and sandyconglomerate semiconsolidados the consolidated Training Pantanal. It contains a unique diversity of soils, often with 2:1 mineralogy, whose morphology reflects the conditions of water regime of each microenvironment: Planosols, Plinthosols, Solonetz, Vertisols and Fluvisols are distributed according to the geomorphic features found, and the great most affected by processes redoximorphic. The goal of this dissertation was to characterize and identify the processes pedogenetic soil of a system pedological Solonetz-Plinthosol in two of the main geomorphic features of the Pantanal of Barão de Melgaço. The study was conducted in RPPN (Private Reserve of Natural Heritage) SESC Pantanal, in the Barão de Melgaço county, State of Mato Grosso from Brazil. The transition of Solonetz for Plinthosol is given by the gradual loss of sodium and increase character of the plintização. As is the reduction of the saturation of Na+, the CEC soil becomes saturated by Al3+. The presence of soil character natric in the hillslope is an evidence of climate changes that occurred in the Pantanal, where the soils relic. The main causes of maintenance of high levels of Na in Solonetz are very closed the porosity of subsurface horizons and high rates of evapotranspiration in the Pantanal. The nodules of Fe and Mn that occur in these soils are not relic and were formed and are still forming in weather conditions to actually.

Les niveaux gargasiens et albiens du Bassin vocontien (Sud-Est de la France) sont constitués par des marnes sombres dénomées "Marnes Bleues". Elles renferment en de nombreux points, des nodules barytiques qui ont été étudiés par PAILLERET (1983) . Une étude minéralogique, granulométrique et géochimique est effectuée sur dix coupes, de situations géographiques et d 'âges différents. La minéralogie des argiles est dominée par l'héritage, et elle permet de différencier trois périodes : - Gargasien - Albien inférieur: l'illite est dominante; - Albien moyen: les smectites prennent le pas sur l'illite; - Albien supérieur: les smectites dominent toujours, mais il apparait une proportion importante de kaolinite. Ces observations sont comparées avec celles de BROSSE (1982) sur les black shales gargaso-albiens de l'Atlantique Central. Un certain nombre d'indices minéralogiques et de relations entre la minéralogie et la géochimie des marnes nous font envisager une origine diagénétique pour certains minéraux: la chlorite, le quartz et certains minéraux entourés d'une auréole de lattes. Il n'existe pas de variations minéralogiques et/ou géochimiques importantes dans les horizons à nodules barytiques. Cependant dans les niveaux à nodules de l'Albien moyen et supérieur. la teneur en Ba est anormalement élevée et se traduit systématiquement par la présence de cristaux de barite (de l'ordre de 1 micron) * dans l'encaissant. L'étude granulométrique couplée aux résultats de l'analyse minéralogique permet de construire un modèle pour expliquer les différents types de croissance des nodules barytiques . Les teneurs anormales en Ba ne sont pas d ' origine détritique : il n'existe aucune relation entre la teneur en Ba dans la roche totale ou la fraction argileuse et la proportion en smectites ou en illites des marnes. Tant que les teneurs en Ba restent faibles, une corrélation avec les quantités de silice biogénique permet de retenir une origine diagénétique pour cet élément. Mais cette relation disparait lorsque les teneurs sont très élevées. Seule l'hypothèse d'une origine hydrothermale peut alors être avancée. Des déc0uvertes récentes (PAULL et al. , 1984) sur un hydrothermalisme "froid" donnent un nouvel éclairage à ce problème.

Thesis (Ph. D.)--University of Bombay, 1969. / Includes bibliographical references (leaves 91-100).

Raramente plantações de eucalipto respondem à adubação nitrogenada. Contudo, por se tratar de povoamentos monoespecíficos, com baixa capacidade de fixação de N, depois de algumas rotações de cultivo a probabilidade de resposta a este nutriente aumenta, devido ao esgotamento das reservas naturais de nitrogênio do solo acumuladas no ecossistema anterior. O presente estudo teve como objetivos avaliar i) o crescimento, o desenvolvimento de raízes finas de Eucalyptus grandis e de Acacia mangium em povoamentos monoespecíficos e mistos; ii) a nodulação da A. mangium nestes povoamentos. As árvores foram plantadas em maio de 2003 no espaçamento 3m x 3m. O delineamento experimental foi o de blocos completamente aleatorizados (4 blocos), sendo avaliados 3 tratamentos: povoamentos monoespecíficos de E. grandis e A. mangium e um povoamento em que essas espécies foram consorciadas (1100 plantas por ha de E. grandis e 550 árvores por ha de A. mangium). Quando consorciada, a A. mangium foi plantada no meio da distância entre as árvores de E. grandis na mesma linha de plantio. Foram amostradas raízes finas vivas (≤3 mm) em 5-16 posições (dependendo do tratamento), de uma árvore de área basal média em doze parcelas (3 tratamentos x 4 blocos), até 1 m de profundidade aos 6 e 12 meses pós-plantio e até 2 m de profundidade aos 18 e 30 meses pós-plantio, por meio de uma sonda de aço com 4,5 cm de diâmetro interno. O E. grandis foi diferente da A. mangium quanto ao desenvolvimento radicular nos diferentes períodos de amostragem, principalmente na camada superficial do solo (0-10 cm). No povoamento misto, aos 30 meses pós-plantio, o E. grandis foi 64% maior em altura do que a A. mangium e 75% maior em área basal, produzindo 94% mais biomassa do que esta leguminosa. A assimetria do crescimento radicular foi elevada entre as espécies, reflexo da grande competição por luz na parte aérea. Não houve clara estratificação de exploração das camadas do solo pelo sistema radicular das espécies. O E. grandis apresentou maior exploração radicular em todas as camadas do solo, fazendo com que o desenvolvimento radicular da A. mangium ficasse restrito a proximidade da árvore. O elevado grau de assimetria no desenvolvimento radicular entre as espécies resultou, aos 30 meses, na camada 0-10 cm, numa diferença de 91% na densidade de raízes finas (drf) entre as espécies. A nodulação foi sensível a competição com o E. grandis, aparentemente, devido à variação de umidade e temperatura sazonal. Aos 18 meses, no povoamento monoespecífico, houve tendência de maior densidade de nódulos na linha de plantio, camada 0-10 cm. Aos 30 meses os nódulos foram encontrados próximos às árvores. No misto, aos 18 e 30 meses ocorreu diminuição da densidade de nódulos na camada 10-30 cm e aumento entre 30 e 50 cm. / Eucalypts plantations rarely answer to the nitrogen fertlization. However, for being of monospecific stands, with low capacity of N fixation, after some cultivation rotations the answer probability to this nutritious one increases, due to the exhaustion of the natural reservations nitrogen of the soil accumulated in previous ecosystem. The present study had as objectives to evaluate i) the growth, the development of Eucalyptus grandis and Acacia mangium fine-root in monospecific and mixed stands; ii) the A. mangium nodulation in these stands. The trees were planted in may of 2003 in the spacing 3m x 3m. The experimental design was it of completely randomized blocks (4 blocks), between assessed 3 treatments: Monospecific stands of E. grandis and A. mangium and a stand in that those species were mixed (1100 plants for ha of E. grandis and 550 trees for ha of A. mangium). When mixed, to A. mangium was planted in the middle of the distance among the trees of E. grandis in the same plantation line. They were sampling live fine-root (≤ 3 mm) in 5-16 positions (depending on the treatment), of a tree of medium basal area in twelve portions (3 treatments x 4 blocks), until 1 m of depth to the 6 and 12 months powder-plantation and until 2 m of depth to the 18 and 30 months powder-plantation, by means of a sledgehammer with 4,5 cm of internal diameter. The E. grandis was different from the A. magium with relationship to the roots development in the different sampling periods, mainly in the superficial layer of the soil (0-10 cm). In the mixed stand, between 29 and 30 months after plantation, E. grandis was 64% larger in height than at A. mangium and 75% larger in basal area, producing 94% more biomass than this leguminous. The asymmetry of the root growth was elevated between the species, reflex of the great competition for light in the aerial part. There was not clear stratification of exploration of the layers of the soil for the roots system of the species. The E. grandis presented larger roots exploration radicular in all the layers of the soil, doing with that the roots development of the A. mangium was restricted in the proximity of the tree. The high asymmetry degree in the roots development between the species, resulted to the 30 months in the layer 0-10 cm, a difference of 91% in the density of fine roots (dfr) between the species. The nodulation was sensitive the competition with the E. grandis , seemingly, due to the humidity variation and seasonal temperature. To the 18 months, in the monospecific stands, there was tendency of larger density of nodules in the plantation line, layer 0-10 cm. To the 30 months the nodules were found close to the trees. In the mixed, to the 18 and 30 months it happened decrease of the density of nodules in the layer 10-30 cm and increase between 30 and 50 cm.

A study of the mineralogy and major element geochemistry of ferromanganese crusts and nodules from the northeastern equatorial Pacific Ocean involved three inter-related projects: ft) the major element geochemistry of crusts and nodules from two study areas, (2) the development of a selective sequential extraction scheme (SSES) and a differential X-ray diffraction technique (DXRD) for the study of the mineralogy of the deposits, and (3) the application of the SSES and DXRD to a small population of crusts and nodules from the two study areas. The objectives of the first project were to relate the composition of the crust and nodule samples to the environment of formation as well as to the mineralogy which could be identified from a bulk powdered sample. The SSES was developed to determine the partitioning of Cu, Ni, and Co concentrations between the Mn and Fe oxides present in crusts and nodules. In developing a SSES, two goals had to be attained: (1) since crust and nodule samples are finite in size and numerous different analyses are to be preformed on a single sample, a SSES should be developed which uses as small amount of sample as feasible, and (2) develop a SSES which is as time efficient as possible. The development of the DXRD in conjuction with the SSES identified which Mn and Fe oxide mineral phase was responsible for hosting Cu, Ni, and Co. In developing the DXRD procedure two other goals had to be attained: (1) use of small leached samples, and (2) recovery of the sample aafter XRD analysis. The purpose of the third project was to test the two analytical procedures on a group of crust and nodule samples which have a wide range in compositions and oxide phase mineralogies. One group of hydrothermal nodules, from Survey Region B, was found to be enriched in Mn and depleted in Fe and Si. The Mn-rich mineral phases were identified as todorokite and birnessite. The second group of hydrothermal nodules, from Survey Region B, was found to be enriched in Fe and Si and depleted in Mn. The Fe-Si rich mineral phase was identified as iron-rich nontronite. Both groups of hydrothermal nodules were depleted in Co, Cu, and Ni. Dymond et al. (1984) and Chen & Owen (1989) identified one group of hydrothermal nodules located close to the East Pacific Rise (EPR) as being enriched in Fe but depleted in Mn, Cu, Ni, and Co. This composition agrees with the Fe-Si rich hydrothermal nodules identified in Survey Region B. Both Dymond et al. (1984) and Chen & Owen (1989), however, interpreted a second group of nodules, close to the EPR, which were enriched in Mn but depleted in Cu, Ni, and Co as suboxic diagenetic deposits. This group of nodules is the Mn-rich end-member composition of hydrothermal nodules identifed in this study. The composition of nodules from Survey Region B indicates there is a correlation between Co abundance and the proximity of the nodules to the hydrothermal discharge from the JEPR. Nodules that are Co-enriched are found farthest away from hydrothermal activity. In contrast, cobalt-depleted nodules coincide with known areas of hydrothermal activity. The SSES and DXRD was applied to a small population of crusts and nodules from the two Survey Regions. The DXRD patterns from the second stage of leaching on the crusts and nodules showed that the iron phase mineralogy in marine crusts and nodules is either akaganeite or ferrihydrite. The DXRD patterns from the second stage of leaching on the Mn-rich hydrothermal crusts and nodules, from Survey Region B, identified the Mn-bearing mineral hausmannite. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate