949 resultados para Arnold, Michael L.: Natural hybridization and evolution
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Natural disasters in Argentina and Chile played a significant role in the state-formation and nation-building process (1822-1939). This dissertation explores state and society responses to earthquakes by studying public and private relief efforts reconstruction plans, crime and disorder, religious interpretations of catastrophes, national and transnational cultures of disaster, science and technology, and popular politics. Although Argentina and Chile share a political border and geological boundary, the two countries provide contrasting examples of state formation. Most disaster relief and reconstruction efforts emanated from the centralized Chilean state in Santiago. In Argentina, provincial officials made the majority of decisions in a catastrophe’s aftermath. Patriotic citizens raised money and collected clothing for survivors that helped to weave divergent regions together into a nation. The shared experience of earthquakes in all regions of Chile created a national disaster culture. Similarly, common disaster experiences, reciprocal relief efforts, and aid commissions linked Chileans with Western Argentine societies and generated a transnational disaster culture. Political leaders viewed reconstruction as opportunities to implement their visions for the nation on the urban landscape. These rebuilding projects threatened existing social hierarchies and often failed to come to fruition. Rebuilding brought new technologies from Europe to the Southern Cone. New building materials and systems, however, had to be adapted to the South American economic and natural environment. In a catastrophe’s aftermath, newspapers projected images of disorder and the authorities feared lawlessness and social unrest. Judicial and criminal records, however, show that crime often decreased after a disaster. Finally, nineteenth-century earthquakes heightened antagonism and conflict between the Catholic Church and the state. Conservative clergy asserted that disasters were divine punishments for the state’s anti-clerical measures and later railed against scientific explanations of earthquakes.
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Actinin and spectrin proteins are members of the Spectrin Family of Actin Crosslinking Proteins. The importance of these proteins in the cytoskeleton is demonstrated by the fact that they are common targets for disease causing mutations. In their most prominent roles, actinin and spectrin are responsible for stabilising and maintaining the muscle architecture during contraction, and providing shape and elasticity to the red blood cell in circulation, respectively. To carry out such roles, actinin and spectrin must possess important mechanical and physical properties. These attributes are desirable when choosing a building block for protein-based nanoconstruction. In this study, I assess the contribution of several disease-associated mutations in the actinin-1 actin binding domain that have recently been linked to a rare platelet disorder, congenital macrothrombocytopenia. I investigate the suitability of both actinin and spectrin proteins as potential building blocks for nanoscale structures, and I evaluate a fusion-based assembly strategy to bring about self-assembly of protein nanostructures. I report that the actinin-1 mutant proteins display increased actin binding compared to WT actinin-1 proteins. I find that both actinin and spectrin proteins exhibit enormous potential as nano-building blocks in terms of their stability and ability to self-assemble, and I successfully design and create homodimeric and heterodimeric bivalent building blocks using the fusion-based assembly strategy. Overall, this study has gathered helpful information that will contribute to furthering the advancement of actinin and spectrin knowledge in terms of their natural functions, and potential unnatural functions in protein nanotechnology.
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The macrofauna assemblages of a XVIIth century shipwreck off southern Portugal were studied and compared with those of nearby natural reefs and sandy bottoms, by underwater visual census. A total of 11 173 specimens of 224 different fauna taxa and 12 phyla were recorded. Natural reefs had the highest density of specimens (35 122 / 1000 m2) followed by the shipwreck (21 392 / 1000 m2) and the sandy bottoms (3771 / 1000 m2). Three biodiversity indices were estimated (Margalef, Shannon- Wiener and Pielou), with the natural reefs showing the highest values. However, the shipwreck presented values relatively similar to those of the natural reefs for the Shannon-Wiener and Pielou indices. The three habitats were clearly distinguishable by multivariate statistical analysis, with the average dissimilarity between sand and shipwreck, and between sand and natural reefs being much higher than that between the shipwreck and the natural reefs. The shipwreck had higher abundances of some commercially important species, such as the pouting Trisopterus luscus, European conger Conger conger, and common spider crab Maja squinado, as well as some vulnerable and threatened species such as the pink seafan Eunicella verrucosa. The results presented emphasize the importance of this habitat on the southern Portuguese coast.
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Cellulose is a biodegradable, renewable, non-meltable polymer which is insoluble in most solvents due to hydrogen bonding and crystallinity. Natural cellulose shows lower adsorption capacity as compared to modified cellulose and its capacity can be enhanced by modification usually by chemicals. This review focuses on the utilization of cellulose as an adsorbent in natural/modified form or as a precursor for activated carbon (AC) for adsorbing substances from water. The literature revealed that cellulose can be a promising precursor for production of activated carbon with appreciable surface area (∼1300 m2 g−1) and total pore volume (∼0.6 cm3 g−1) and the surface area and pore volume varies with the cellulose content. Finally, the purpose of review is to report a few controversies and unresolved questions concerning the preparation/properties of ACs from cellulose and to make aware to readers that there is still considerable scope for future development, characterization and utilization of ACs from cellulose.
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Cellulose is a biodegradable, renewable, non-meltable polymer which is insoluble in most solvents due to hydrogen bonding and crystallinity. Natural cellulose shows lower adsorption capacity as compared to modified cellulose and its capacity can be enhanced by modification usually by chemicals. This review focuses on the utilization of cellulose as an adsorbent in natural/modified form or as a precursor for activated carbon (AC) for adsorbing substances from water. The literature revealed that cellulose can be a promising precursor for production of activated carbon with appreciable surface area ( 1300 m2 g 1) and total pore volume ( 0.6 cm3 g 1) and the surface area and pore volume varies with the cellulose content. Finally, the purpose of review is to report a few controversies and unresolved questions concerning the preparation/properties of ACs from cellulose and to make aware to readers that there is still considerable scope for future development, characterization and utilization of ACs from cellulose.
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2016
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2016
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Os roedores Echimyidae tem distribuição Neotropical e são a família mais diversa de roedores Caviomorpha. Apesar da grande diversidade, pouco se sabe sobre a distribuição geográfica, história natural e evolução de vários grupos de equimídeos. O histórico taxonômico dessa família é confuso, sendo alguns grupos raramente coletados e, consequentemente, inferências sobre aspectos evolutivos e biológicos são pouco conclusivas e limitadas à análise de poucos exemplares. Filogenias moleculares não corroboram a classificação taxonômica para a família baseada em dados morfológicos, evidenciando a complexidade da história evolutiva desse grupo. Na Mata Atlântica são registrados cinco gêneros de Echimyidae: o rato-do-bambu, Kannabateomys; os arborícolas Phyllomys e Callistomys; o terrestre Trinomys, e o semi-fossorial Euryzygomatomys. O presente trabalho se baseou na utilização de sequências de DNA para abordar aspectos da evolução e filogenia de roedores equimídeos da Mata Atlântica em três níveis taxonômicos: família, gênero e espécie. O primeiro capítulo aborda a posição filogenética do gênero Callistomys dentro da família, utilizando sequências de 1 marcador mitocondrial (CitB) e 3 nucleares (GHR, RAG1 e vWF). Os resultados mostram que Callistomys forma um clado com o ratão-do-banhado (Myocastor), roedor semi-aquático das regiões abertas no cone sul da América do Sul e com o rato-de-espinho terrestre Proechimys com ocorrência na Amazônia. Esse clado é irmão de Thrichomys, um equimídeo terrestre que ocupa as áreas secas do centro da América do Sul. O agrupamento encontrado é inesperado, uma vez que seus membros apresentam aspectos morfológico, ecológicos e distribuição geográfica distintos e contrastantes. A filogenia resultante indica que Callistomys não é proximamente relacionado aos outros equimídeos arborícolas e sugere que o hábito arborícolas evoluiu mais de uma vez na família. O segundo capítulo investiga aspectos da filogenia, evolução e limites entre espécies de Phyllomys utilizando dois marcadores mitocondriais (CitB e COI) e três nucleares (GHR, RAG1 e vWF). Foram identificados três grupos principais de espécies: um com distribuição longitudinal pela porção central da Mata Atlântica (P. pattoni (P. mantiqueirensis, Phyllomys sp. 4)); e a partir daí dois outros grupos, um com distribuição na porção norte da Mata Atlântica (Phyllomys sp. 2 (P. blainvilii (P. brasiliensis, P. lamarum))); e outro na porção sul (Phyllomys sp. 3 ((Phyllomys sp. 1, P. lundi), (Phyllomys sp. 5 (P. dasythrix (P. nigrispinus (P. sulinus, Phyllomys sp. 6)))))). Foram identificadas duas linhagens independentes representando possíveis espécies novas, elevando o potencial número de espécies do gênero de 17 para 19. As filogenias associadas aos dados de distribuição geográfica sugerem que a diversificação e distribuição das espécies de Phyllomys foi influenciada pela ação conjunta de vários fatores como atividade neotectônica, gradientes altitudinais e latitudinais e mudanças climáticas que atuaram desde o Mioceno, marcando os primeiros eventos de diversificação do gênero até as especiações mais recentes, no Pleistoceno. O terceiro capítulo avalia a variação genética, distribuição geográfica e status taxonômico da espécie Euryzygomaotmys spinosus utilizando dois marcadores mitocondriais (CitB e D-loop). Os resultados mostraram que E.spinosus apresenta distribuição em áreas de Mata Atlântica e adjacências ao sul do Rio Doce, no Brasil, Paraguai e Argentina, incluindo um registro confirmado no Cerrado. A espécie ocupa habitats muito diversos e pode ser considerada generalista. As populações são geneticamente estruturadas ao longo da sua distribuição e os dados genéticos corroboram a taxonomia atual que considera apenas uma espécie, E. spinosus, para o gênero.
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Introducción: El trasplante hepático es la terapia de elección para los pacientes con enfermedad hepática terminal, logrando mejorar su expectativa y calidad de vida, de acuerdo a estudios realizados en otros países. En la Fundación Cardioinfantil – Instituto de Cardiología (FCI-IC) se han realizado 332 trasplantes hepáticos hasta el 2014, pero no se conoce la supervivencia y los factores pronósticos propios de los pacientes intervenidos. Objetivo Principal: Estimar la supervivencia a 1, 3 y 5 años e identificar los principales factores pronósticos de los pacientes a quienes se les realizó trasplante hepático en el periodo 2005-2013 en la FCI-IC. Método: Estudio observacional y retrospectivo, basado en revisión de historias clínicas de los pacientes adultos a quienes se les realizó trasplante hepático en el periodo 2005-2013 en la FCI-IC. Resultados: La supervivencia al año fue de 90.91% (IC95% 86.40-93.98), a los 3 años 83.64% (IC95% 77.89-88.01) y a los 5 años de 79.18% (IC95% 72.54-84.39). Los principales factores pronósticos fueron el antecedente de ascitis (HR 2.449, IC 1.252 – 4.792), la edad del donante (HR 1.040, IC 1.009 – 1.071) y el receptor (HR 1.037, IC 1.014 – 1.060). Se encontró una mayor supervivencia en los pacientes con cirrosis alcohólica (HR 0.099, IC 0.021 – 0.467). Conclusiones: El estudio mostró una supervivencia mayor a la reportada en estudios realizados en Estados Unidos (67.4-73.0% a los 5 años) y España (73,3% a los 3 años) y similar a la de Chile (80.0% a los 5 años). Cabe resaltar que estos estudios incluyeron series más grandes de pacientes.
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Introducción: El trasplante hepático ortotópico es la colocación de un nuevo hígado en la misma ubicación del explantado. El objetivo es prolongar la duración y la calidad de vida en pacientes con enfermedades hepáticas terminales. Sin embargo, las infecciones bacterianas son una complicación en los pacientes receptores del trasplante, comprometiendo el éxito del procedimiento. El objetivo fue determinar los factores asociados a infecciones bacterianas en el primer mes tras realizada la intervención y describir las características demográficas de esa población. De 332 trasplantes realizados, que 262 cumplieron criterios para el análisis. Métodos: Se realizó un estudio observacional analítico de casos y controles anidado en una cohorte, en mayores de 18 años, receptores de trasplante hepático primario, de la FCI-IC de 2005 a 2014; excluyendo trasplante combinado hígado riñón, retrasplantes o fallecidos por causa diferente a la infecciosa durante el primer mes. Resultados: Se encontró que la ventilación mecánica por más de 1 día, el catéter venoso central mayor de 3 días son los principales factores de riesgo para infecciones bacterianas. La albúmina mayor de 2,6gr/dl se asoció a menor infección. Los agentes etiológicos predominantes fueron gérmenes gram negativos como E. coli, K. pneumonia y E. cloacae. Mientras que bacteremia, infección urinaria y peritonitis fueron las infecciones más frecuentes. La incidencia de infección bacteriana en esta población fue 24%. Discusión: Se recomienda por tanto extubación antes de 24 horas, uso de catéter central menor de 3 días y limitar el uso del catéter vesical.
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This research focuses on taxonomy, phylogeny and reproductive ecology of Gentiana lutea. L.. Taxonomic analysis is a critical step in botanical studies, as it is necessary to recognize taxonomical unit. Herbarium specimens were observed to assess the reliability of several subspecies-diagnostic characters. The analysis of G. lutea genetic variability and the comparison with that of the other species of sect. Gentiana were performed to elucidate phylogenetic relationships among G. lutea subspecies and to propose a phylogenetic hypothesis for the evolution and the colonization dynamics of the section. Appropriate scientific information is critical for the assessment of species conservation status and for effective management plans. I carried out field work on five natural populations and performed laboratory analyses on specific critical aspects, with special regard to G. lutea breeding system and type and efficiency of plant-pollinator system. Bracts length is a reliable character to identify subsp. vardjanii, however it is not exclusive, hence to clearly identify subsp. vardjanii, other traits have to be considered. The phylogenetic hypotheses obtained from nuclear and chloroplast data are not congruent. Nuclear markers show a monophyly of sect. Gentiana, a strongly species identity of G. lutea and clear genetic identity of subsp. vardjanii. The little information emerging from plastid markers indicate a weak signal of hybridization and incomplete sorting of ancestral lineages. G. lutea shows a striking variation in intra-floral dichogamy probably evolved to reduce pollen-stigma interference. Although the species is partially self-compatible, pollen vectors are necessary for a successful reproduction, and moreover it shows a strong inbreeding depression. G. lutea is a generalist species: within its spectrum of visitors is possible to recognize "nectar thieves" and pollinators with sedentary or dynamic behaviour. Pollen limitation is frequent and it could be mainly explained by poor pollen quality.
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The exponential growth of studies on the biological response to ocean acidification over the last few decades has generated a large amount of data. To facilitate data comparison, a data compilation hosted at the data publisher PANGAEA was initiated in 2008 and is updated on a regular basis (doi:10.1594/PANGAEA.149999). By January 2015, a total of 581 data sets (over 4 000 000 data points) from 539 papers had been archived. Here we present the developments of this data compilation five years since its first description by Nisumaa et al. (2010). Most of study sites from which data archived are still in the Northern Hemisphere and the number of archived data from studies from the Southern Hemisphere and polar oceans are still relatively low. Data from 60 studies that investigated the response of a mix of organisms or natural communities were all added after 2010, indicating a welcomed shift from the study of individual organisms to communities and ecosystems. The initial imbalance of considerably more data archived on calcification and primary production than on other processes has improved. There is also a clear tendency towards more data archived from multifactorial studies after 2010. For easier and more effective access to ocean acidification data, the ocean acidification community is strongly encouraged to contribute to the data archiving effort, and help develop standard vocabularies describing the variables and define best practices for archiving ocean acidification data.