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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Darwinismo universal à luz da auto-organização : implicações evolutivas na origem da ordem biológica

Alabí, Letícia Paola January 2014 (has links)
Orientador: Prof. Dr. Charles Morphy D. Santos / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Programa de Pós-Graduação em Ensino, História, Filosofia das Ciências e Matemática, 2014. / O Darwinismo Universal, conceito desenvolvido pelo biólogo evolucionista Richard Dawkins em 1983, responde positivamente à conjectura "Se existe vida fora da Terra, os organismos evoluem como evoluem os seres vivos da Terra?". No entanto, a complexidade adaptativa centrada na seleção natural, seria por si só, aqui ou em qualquer parte do Universo, suficiente para explicar toda a evolução orgânica? O próprio Charles Darwin defendia um pluralismo explicativo para a evolução. A proposta central do trabalho é discutir se uma definição geral de vida pode estar fundamentada na ideia de seleção natural ou se precisamos rediscutir e estender o conceito de Darwinismo Universal à luz de conceitos tais como a auto-organização, que poderia explicar a origem da ordem biológica a partir de características intrínsecas dos sistemas físico-químicos. Também faz parte do escopo do projeto apontar falhas e indevidas extrapolações do Darwinismo associadas a modelos cosmológicos, assim como a não universalidade do conceito frente a tradicional definição universal de vida. Pela falta de uma definição mais ampla do que é vida, a detecção de bioassinaturas ¿ atributos químicos, físicos ou fisiológicos que denotam, necessariamente, a presença de organismos ¿ torna-se limitada por se restringir apenas àquilo que, independentemente do lugar que ocupa no Universo, passa por um processo natural de seleção darwiniana. Tão logo, deve-se buscar uma compreensão universal da vida como um fenômeno emergente coerente. A expansão do conceito de Darwinismo Universal à luz de uma extensão (ou síntese estendida) da Teoria da Evolução ¿ no componente auto-organização ¿ servirá como arcabouço preliminar para uma filosofia da Biologia apta a abarcar a origem da ordem e diversificação de todas as formas de vida na Terra e para determinar diretrizes as buscas de bioassinaturas. / Universal Darwinism, a concept developed by the evolutionary biologist Richard Dawkins in 1983, responds positively to the conjecture "If life out of Earth exists, does it evolve as Earth¿s living beings do?". Nevertheless, the adaptative complex centered in Darwinian evolution and, therefore, in natural selection, would be by itself, here or at any part of the Universe, sufficient to explain all the organic evolution? Charles Darwin himself used to defend an explicative pluralism for evolution. The main purpose of the present work is to discuss if a general definition of life can be uniquely based on natural selection or whether a new discussion and understanding of the Universal Darwinism under the light of concepts like self-organization is required, which would be able to explain the origin of biological order from physicochemical systems intrinsic characteristics. It is also part of this project¿s scope to point out flaws and improper Darwinism extrapolations associated to cosmological models, as well as the concept¿s non-universality faced with life¿s traditional universal definition. By the lack of a broader definition of life, the detection of biosignatures ¿ chemical, physical or physiological attributes which betoken necessarily, the presence of organisms ¿ becomes limited by restricting only what, independently from where it is located in the universe, undergoes a Darwinian natural selection process. Therefore, it is necessary to search for a universal life comprehension as a coherent emerging phenomenon. The expansion of Universal Darwinism under the light of an extension (or extended synthesis) of the Evolutionary theory ¿ at the self-organization component ¿ will serve as preliminary scaffold for a philosophy of biology able to embrace the origin of order and the diversification of all life forms on Earth, and to determine guidelines for biosignatures searches.
12

Levantamento e estudo das ocorrências de grafita do Distrito Grafitífero Aracoiába-Baturité, CE / Survey and study of graphite occurrences in the Aracoiába-Baturité graphite bearing District, CE

Paulo Roberto Pizarro Fragomeni 23 March 2011 (has links)
O Distrito Grafitífero Aracoiába-Baturité apresenta depósitos do tipo gnaisse grafitoso (minério disseminado) e veio (minério maciço) com diferentes origens genéticas e com características físicas e ambientes geológicos de formação próprios. O minério tipo gnaisse grafitoso é de origem sedimentar, singenético, com teores de 1,5 a 8% de C, que se distribuem ao longo de duas extensas faixas paralelas, hospedadas na Subunidade Baturité, que constitui um importante metalotecto regional. A associação de grafita metamórfica disseminada em metassedimentos da Sequência Acarápe constitui um geoindicador de antiga bacia sedimentar neoproterozóica e, também, pode ser considerado como zona de geosutura resultante do subsequente fechamento de um oceano primitivo. As rochas desta subunidade correspondem na paleogeografia da Sequência Acarápe aos fácies de sopé de talude e de planície abissal. O minério tipo veio (fluido depositado) é epigenético e, com teores entre 20% e 70% de C, forma corpos tabulares e bolsões, controlados em escala local por estruturas de alívio (falhas, fraturas, zonas de contato, eixos de dobras etc.) que permitiram a percolação de soluções penumatolíticas relacionadas ao corpo plutônico de Pedra Aguda. As variações dos valores das relações entre isótopos estáveis de carbono (δ13C) na grafita do minério disseminado são de -26,72 a -23,52 e do minério maciço de -27,03 a -20,83, revelando sinal de atividades biológicas (bioassinaturas) e permitem afirmar que a grafita das amostras acima são derivadas de matéria orgânica. Foram apresentados os principais guias de prospecção para grafita e testados os seguintes métodos geofísicos: Eletro-Resistividade; GPR - Ground Penetrating Radar; Magnetometria; VLF (Very Low Frequency); e Polarização Induzida Espectral (IPS) / Resistividade (ER). A conjugação dos métodos de Polarização Induzida Espectral (IPS) e Eletro Resistividade (ER) foi o que demonstrou a melhor eficiência. Com relação à determinação do teor de carbono por termogravimetria (ATG), que é o método mais utilizado para este elemento. Verificou-se, que as faixas de queima atribuídas ao carbono no minério do Distrito de Aracoiába-Baturité (340 a 570C e de 570 a 1050C) eram diferentes das faixas do minério de Minas Gerais (350C a 650C e 650C a 1.050C). Esta constatação indica a necessidade de se determinar previamente as faixas de temperatura para cada região pesquisada. / The Aracoiába-Baturité Graphite-bearing District has graphitic gneiss deposits (disseminated ore) and vein (solid ore) with different genetic origins and their own physical characteristics and geological environments. The graphite gneiss ore is of sedimentary, syngenetic origin, with 1.5% to 8% C content, which is distributed along two long parallel belts, hosted in the Baturité Sub-unit, which consists of a major regional metallotect. The association of metamorphic graphite disseminated in metasediments of the Acarápe Sequence consists of a geoindicator of an old Neo-Proterozoic sedimentary basin and also can be considered a geosuture zone, the result of the subsequent closing of a primitive ocean. The rocks of this subunit correspond in the paleogeography of the Acarápe Sequence to the facies of the bottom of a slope and of an abyssal plain. The vein ore (deposited fluid) is epigenetic and, with C contents of between 20% and 70%, forms tabular bodies and pockets, controlled on a local scale by relief structures (faults, fractures, contact zones, fold axes, etc.), which allowed seepage of pneumatolithic solutions relating to the plutonic body of Pedra Aguda. The variations in the values of the ratios between stable carbon isotopes (δ13C) in the graphite of the disseminated ore are -26.72 to -23.52 and of the solid ore -27.03 to -20.83, showing a sign of biological activities (biosignatures), and it can be said that the graphite of the above samples is derived from organic matter. The main prospecting guides for graphite were presented and the following geophysical methods tested: Electro-resistivity (ER); Ground Penetrating Radar (GPR); Magnetometry; Very Low Frequency (VLF); and Spectral Induced Polarization (SIP) / Electro-resistivity (ER). It was found that the combination of the Spectral Induced Polarization (SIP) and Electro-resistivity (ER) methods proved the most efficient. In relation to determining the carbon content using thermogravimetry (TG), which is the most commonly used method for this element, it was found that the bands of burning attributed to the carbon in the ore in the Aracoiába-Baturité District (340 to 570C and from 570oC to 1050C) were different from the bands of the ore in Minas Gerais (350C to 650C and 650C to 1050C). This finding suggests the need to determine beforehand the temperature ranges for each region studied.
13

Isotopic Investigations of Carbon Cycling And Microbially Influenced Carbonate Precipitation In Freshwater Microbialites And Carbonate-Rich Microbial Mats / Microbial Carbon Cycling and Isotope Biosignatures

Brady, Allyson Lee January 2009 (has links)
<p>Modern microbialites and microbial mats are the focus of ongoing research as they provide an opportunity to understand microbial-mineral interactions during carbonate precipitation and the generation of biosignatures that can inform our interpretation of the geological record. This study determined the natural abundance isotopic compositions ([13]C, [14]C) of the primary carbon pools and microbial communities associated with modern freshwater microbialites located in Pavilion Lake and in carbonate rich microbial mats on the nearby Cariboo Plateau in British Columbia, Canada. </p> <p> Natural abundance [14]C analysis of carbon pools associated with the Pavilion Lake microbialites demonstrated that structures were actively growing and that groundwater carbon inputs to the lake and microbialites were minimal. Rather, ambient dissolved inorganic carbon (DIC) was the primary carbon source for both microbial communities and recent carbonate. </p> <p> Isotopic enrichment of calcium carbonate within microbial communities associated with the microbialites was identified as a biosignature of microbial photosynthetic influence driving precipitation. Elevated oxygen concentrations and pH within the microenvironment of small, sporadic nodular microbial surface communities was concurrent with in situ precipitation of carbonate with δ[13]C values higher than predicted abiotic values and δ[13]C of bulk organic matter and phospholipid fatty acids (PLFA) that were consistent with a photosynthetically dominated community. Elevated carbonate δ[13]C values were also noted in the thin surface microbial mat recovered from shallow (11m) microbialites. These samples showed increased biomass during summer sampling periods as compared to deeper samples, consistent with expected high rates of photosynthetic activity due to higher light levels and temperature at these depths. These results contrast other recent studies of modern microbialite systems that identified biosignatures of heterotrophic influences on precipitation of carbonates. PLFA profiles demonstrated that the surface microbial mat community consisting of both photosynthetic and heterotrophic microbes was stable over seasonal and spatial changes in light and temperature. However, changes in microbial biomass with depth and season indicated that microbial activity and growth plays an important role in the development of isotopic biosignatures. </p> <p> Biosignatures of high levels of photosynthetic activity were also observed in carbonate, rich microbial mats that exhibited undersaturated p CO2 concentrations during the summer and DIC δ[13]C values enriched above values predicted for isotopic equilibrium with atmospheric CO2. Seasonal and annual shifts in the balance of heterotrophy and autotrophy in the lakes and microenvironment of the mat accounted for observed variations in DIC and associated carbonate δ[13]C values. In contrast to other organic rich microbial mats, bulk organic δ[13]C values were not enriched and the systems did not show evidence of CO2 limitation. Rather, these results indicated that low bulk organic δ[13]C values and large isotopic discriminations can exist under conditions of high DIC concentrations and carbonate content that provide a non limiting carbon source to replenish photosynthetic drawdown. </p> / Thesis / Doctor of Philosophy (PhD)
14

An integrated approach to the study of biosignatures in mineralizing biofilms and microbial mats / Ein umfassender Ansatz zur Untersuchung von Lebensspuren in mineralisierenden Biofilmen und mikrobiellen Matten

Heim, Christine Nora 09 July 2010 (has links)
No description available.
15

CHARACTERIZATION OF DIAGNOSTIC BIOSIGNATURES FOR PARKINSON’S DISEASE AND RENAL CELL CARCINOMA THROUGH QUANTITATIVE PROTEOMICS AND PHOSPHOPROTEOMICS ANALYSES OF URINARY EXTRACELLULAR VESICLES

Marco Hadisurya (16548114) 26 July 2023 (has links)
<p>Urine-based biomarkers offer numerous advantages for clinical analysis, including non-invasive collection, a suitable sample source for longitudinal disease monitoring, a better screenshot of disease heterogeneity, higher sample volumes, faster processing times, and lower rejection rates and costs. They will be extremely useful in a clinical trial context, which can be applied alone or in combination with other methods as long as they demonstrate clear reproducibility across cohorts. While biofluids such as urine present enormous challenges with a wide dynamic range and extreme complex typically dominated by a few highly abundant proteins, we have demonstrated that the analytical issue can be efficiently addressed by focusing on extracellular vesicles (EVs), tiny packages released by all kinds of cells. These tiny packages contain different kinds of molecules from inside the cells. Here, we established a robust EV isolation and characterization platform to screen and validate Parkinson’s Disease (PD) and Renal Cell Carcinoma (RCC) biomarkers from urine. PD is a progressive neurological disorder affecting body movement because some brain cells stop producing dopamine. PD is often not diagnosed until it has advanced, making early detection crucial. We investigated urinary EVs from 138 individuals to enable early detection and found several proteins involved in PD development that could be biological indicators for early disease detection. Several biochemical techniques were applied to verify our findings. In the second project, we attempted to develop a novel diagnostic technique for early intervention of RCC. Here, we made our efforts to develop a quantitative method based on data-independent acquisition (DIA) mass spectrometry to analyze urinary EV phosphoproteomics for non-invasive RCC biomarker screening. Combined with our in-house EVtrap method for EV isolation and PolyMAC enrichment of phosphopeptides, we quantified 2,584 unique phosphosites. We observed unique upregulated phosphosites and pathways differentiating healthy control (HC), chronic kidney disease (CKD), low-grade, and high-grade clear cell RCC. These applications have a significant promise for early PD and RCC diagnosis and monitoring based on actual functional proteins with urine as the source. These studies might provide a viable path to developing urinary EV-based disease diagnosis.</p>

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