976 resultados para AVELLANEDA, NICOLAS
Resumo:
The 23rd Annual Symposium on Sea Turtle Biology and Conservation was held between 17 and 21 March 2003 at The Legend Hotel in Kuala Lumpur, Malaysia, hosted by the Community Conservation Network, Hawaii, and WWF-Malaysia. The meeting was attended by slightly more than 300 participants representing 73 countries, a dramatic drop in participation from previous years brought about in no small part by the looming war in the middle east region and concerns over travel safety. For 22 years the Symposium had bee an Americas-based event, even though it is the annual gathering of the "international" sea turtle society, and with the move to Malaysia, the Symposium hoped to raise the awareness among the general public of the plight of amrine turtles in Southeast Asia, and share the enormous exspertise of the world authorities on sea turtles with this so-far underrepresented region. Adopting the thems, "Living With Turtles", the Symposium had a very personal flavour, and the smaller number of participants made it possible to make and renew acquaintances, and have time for discussion between sessions. While the travel safety concern excuse was often quoted, it was a pity, particularly to the large contingent of people who attended the event for the first time from underrepresented regions, that many of the household names linked to marine turtle biology and conservation were not present to share their knowledge and promote the global concerns on the plight of turtle populations.
Resumo:
Granular crystals are compact periodic assemblies of elastic particles in Hertzian contact whose dynamic response can be tuned from strongly nonlinear to linear by the addition of a static precompression force. This unique feature allows for a wide range of studies that include the investigation of new fundamental nonlinear phenomena in discrete systems such as solitary waves, shock waves, discrete breathers and other defect modes. In the absence of precompression, a particularly interesting property of these systems is their ability to support the formation and propagation of spatially localized soliton-like waves with highly tunable properties. The wealth of parameters one can modify (particle size, geometry and material properties, periodicity of the crystal, presence of a static force, type of excitation, etc.) makes them ideal candidates for the design of new materials for practical applications. This thesis describes several ways to optimally control and tailor the propagation of stress waves in granular crystals through the use of heterogeneities (interstitial defect particles and material heterogeneities) in otherwise perfectly ordered systems. We focus on uncompressed two-dimensional granular crystals with interstitial spherical intruders and composite hexagonal packings and study their dynamic response using a combination of experimental, numerical and analytical techniques. We first investigate the interaction of defect particles with a solitary wave and utilize this fundamental knowledge in the optimal design of novel composite wave guides, shock or vibration absorbers obtained using gradient-based optimization methods.
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Na virada para o século XXI artistas e curadores em bienais e outras exposições internacionais estão adotando formas colaborativas e educacionais de fazer arte e curadoria envolvendo artistas e não artistas, comunidades, escolas e outras instâncias sociais. Essas iniciativas criam encontros interdisciplinares onde imbricações entre arte e não-arte são colocadas em questão, considerando contextos sociopolíticos mundiais, a globalização e outros temas pós-colonialistas. A dissertação examina as aproximações e atravessamentos de culturas e identidades, questões de centro e periferia, local e global gerando entre-lugares e o interesse por propostas de site-oriented, geradoras de situações de convivência, compartilhamento de experiências coletivas e prática educativa. A pesquisa reflete sobre as intenções dos artistas, curadores, a participação do público e o diálogo entre diferentes discursos críticos e campos do conhecimento em projetos com essas características. O estudo de caso é o projeto Cadernos de Viagem, projeto de residência artística e exposição, realizado na 8 Bienal do Mercosul, em Porto Alegre, Brasil, 2011. Diversos teóricos como Homi Bhabha, Jacques Rancière, Nicolas Bourriaud, Claire Bishop, Grant Kester, Miwon Kwon, Moacir dos Anjos e Félix Guattari, são abordados, entre outros
Utilização de métodos de comparação de sequências para a detecção de genes taxonomicamente restritos
Resumo:
Desde a década de 1990, os esforços internacionais para a obtenção de genomas completos levaram à determinação do genoma de inúmeros organismos. Isto, aliado ao grande avanço da computação, tem permitido o uso de abordagens inovadoras no estudo da estrutura, organização e evolução dos genomas e na predição e classificação funcional de genes. Entre os métodos mais comumente empregados nestas análises está a busca por similaridades entre sequências biológicas. Análises comparativas entre genomas completamente sequenciados indicam que cada grupo taxonômico estudado até o momento contém de 10 a 20% de genes sem homólogos reconhecíveis em outras espécies. Acredita-se que estes genes taxonomicamente restritos (TRGs) tenham um papel importante na adaptação a nichos ecológicos particulares, podendo estar envolvidos em importantes processos evolutivos. Entretanto, seu reconhecimento não é simples, sendo necessário distingui-los de ORFs não-funcionais espúrias e/ou artefatos derivados dos processos de anotação gênica. Além disso, genes espécie- ou gêneroespecíficos podem representar uma oportunidade para o desenvolvimento de métodos de identificação e/ou tipagem, tarefa relativamente complicada no caso dos procariotos, onde o método padrão-ouro na atualidade envolve a análise de um grupo de vários genes (MultiLocus Sequence Typing MLST). Neste trabalho utilizamos dados produzidos através de análises comparativas de genomas e de sequências para identificar e caracterizar genes espécie- e gênero-específicos, os quais possam auxiliar no desenvolvimento de novos métodos para identificação e/ou tipagem, além de poderem lançar luz em importantes processos evolutivos (tais como a perda e ou origem de genes em linhagens particulares, bem como a expansão de famílias de genes em linhagens específicas) nos organismos estudados.
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No presente trabalho, busca-se refletir, em primeiro lugar, sobre as funções sociais da produção, da circulação e do consumo de bens culturais. Com esse objetivo, realiza-se uma análise crítica acerca das formas predominantes desde as quais foram interpretados esses processos, concedendo especial ênfase no papel que cumprem na construção simbólica de certa ordem social. Define-se a produção de bens culturais como uma objetivação de uma subjetividade determinada, e, em tal sentido, se considera como uma construção discursiva onde subjazem determinadas visões do mundo, contribuindo, desse modo, com uma produção simbólica específica. No entanto, sem desconhecer a formação de hegemonias e a sua pretensão de imposição, entende-se, no presente trabalho, que a construção de sentido não pode ser considerada como a imposição plena do objeto sobre o sujeito, senão como uma interação entre ambos. O significado é fruto de um processo interativo entre a história do processo de produção e a história incorporada nos esquemas de classificação que possuem os sujeitos de distintos espaços sociais. Em segundo lugar, considerando os resultados do survey sobre consumo cultural feita no ano 2009 no Uruguai, realiza-se uma discussão sobre as especificidades que este processo assume no citado país, bem como acerca do papel das políticas culturais e sua concepção regressiva da distribuição de fundos públicos, o que redunda no fortalecimento da exclusão simbólica dos setores com menores recursos.
Resumo:
Background: There is growing evidence that microglia are key players in the pathological process of amyotrophic lateral sclerosis (ALS). It is suggested that microglia have a dual role in motoneurone degeneration through the release of both neuroprotective and neurotoxic factors. Results: To identify candidate genes that may be involved in ALS pathology we have analysed at early symptomatic age (P90), the molecular signature of microglia from the lumbar region of the spinal cord of hSOD1(G93A) mice, the most widely used animal model of ALS. We first identified unique hSOD1(G93A) microglia transcriptomic profile that, in addition to more classical processes such as chemotaxis and immune response, pointed toward the potential involvement of the tumour suppressor gene breast cancer susceptibility gene 1 (Brca1). Secondly, comparison with our previous data on hSOD1(G93A) motoneurone gene profile substantiated the putative contribution of Brca1 in ALS. Finally, we established that Brca1 protein is specifically expressed in human spinal microglia and is up-regulated in ALS patients. Conclusions: Overall, our data provide new insights into the pathogenic concept of a non-cell-autonomous disease and the involvement of microglia in ALS. Importantly, the identification of Brca1 as a novel microglial marker and as possible contributor in both human and animal model of ALS may represent a valid therapeutic target. Moreover, our data points toward novel research strategies such as investigating the role of oncogenic proteins in neurodegenerative diseases.
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Rio del Rio Hortega (1882-1945) discovered microglia and oligodendrocytes (OLGs), and after Ramon y Cajal, was the most prominent figure of the Spanish school of neurology. He began his scientific career with Nicolas Achucarro from whom he learned the use of metallic impregnation techniques suitable to study non-neuronal cells. Later on, he joined Cajal's laboratory. and Subsequently, he created his own group, where he continued to develop other innovative modifications of silver staining methods that revolutionized the study of glial cells a century ago. He was also interested in neuropathology and became a leading authority on Central Nervous System (CNS) tumors. In parallel to this clinical activity, del Rio Hortega rendered the first systematic description of a major polymorphism present in a subtype of macroglial cells that he named as oligodendroglia and later OLGs. He established their ectodermal origin and suggested that they built the myelin sheath of CNS axons, just as Schwann cells did in the periphery. Notably, he also suggested the trophic role of OLGs for neuronal functionality, an idea that has been substantiated in the last few years. Del Rio Hortega became internationally recognized and established an important neurohistological school with outstanding pupils from Spain and abroad, which nearly disappeared after his exile due to the Spanish civil war. Yet, the difficulty of metal impregnation methods and their variability in results, delayed for some decades the confirmation of his great insights into oligodendrocyte biology until the development of electron microscopy and immunohistochemistry. This review aims at summarizing the pioneer and essential contributions of del Rio Hortega to the current knowledge of oligodendrocyte structure and function, and to provide a hint of the scientific personality of this extraordinary and insufficiently recognized man.
Resumo:
In the present study we have investigated the population genetic structure of albacore (Thunnus alalunga, Bonnaterre 1788) and assessed the loss of genetic diversity, likely due to overfishing, of albacore population in the North Atlantic Ocean. For this purpose, 1,331 individuals from 26 worldwide locations were analyzed by genotyping 75 novel nuclear SNPs. Our results indicated the existence of four genetically homogeneous populations delimited within the Mediterranean Sea, the Atlantic Ocean, the Indian Ocean and the Pacific Ocean. Current definition of stocks allows the sustainable management of albacore since no stock includes more than one genetic entity. In addition, short-and long-term effective population sizes were estimated for the North Atlantic Ocean albacore population, and results showed no historical decline for this population. Therefore, the genetic diversity and, consequently, the adaptive potential of this population have not been significantly affected by overfishing.
Resumo:
Under the guidance of Ramon y Cajal, a plethora of students flourished and began to apply his silver impregnation methods to study brain cells other than neurons: the neuroglia. In the first decades of the twentieth century, Nicolas Achucarro was one of the first researchers to visualize the brain cells with phagocytic capacity that we know today as microglia. Later, his pupil Pio del Rio-Hortega developed modifications of Achucarro's methods and was able to specifically observe the fine morphological intricacies of microglia. These findings contradicted Cajal's own views on cells that he thought belonged to the same class as oligodendroglia (the so called "third element" of the nervous system), leading to a long-standing discussion. It was only in 1924 that Rio-Hortega's observations prevailed worldwide, thus recognizing microglia as a unique cell type. This late landing in the Neuroscience arena still has repercussions in the twenty first century, as microglia remain one of the least understood cell populations of the healthy brain. For decades, microglia in normal, physiological conditions in the adult brain were considered to be merely "resting," and their contribution as "activated" cells to the neuroinflammatory response in pathological conditions mostly detrimental. It was not until microglia were imaged in real time in the intact brain using two-photon in vivo imaging that the extreme motility of their fine processes was revealed. These findings led to a conceptual revolution in the field: "resting" microglia are constantly surveying the brain parenchyma in normal physiological conditions. Today, following Cajal's school of thought, structural and functional investigations of microglial morphology, dynamics, and relationships with neurons and other glial cells are experiencing a renaissance and we stand at the brink of discovering new roles for these unique immune cells in the healthy brain, an essential step to understand their causal relationship to diseases.
Resumo:
Este trabalho tem por objetivo investigar processos de criação no campo do ensino das artes através de propostas desenvolvidas em oficinas de artes visuais. Os interlocutores desta pesquisa foram seis jovens com diferentes deficiências: Síndrome Down, deficiência física e deficiência intelectual, matriculados na rede pública de ensino. Os processos de criação aqui tratados revelaram que os variados repertórios utilizados por este grupo para criarestão fortemente atrelados à produção veiculada pelas mídias na contemporaneidade. Dentre as produções de maior recorrência verificadas no interior das narrativas dos jovens estão: a produção da TV, do cinema e das histórias em quadrinhos. As investigações sobre os processos de criação deste grupo se deram tanto a partir dos seus processos individuais quanto dos coletivos. O conceito de processos de criação compreendido neste trabalho está vinculado ao pensamento de Mikhail Bakhtin, Lev Vigotski e Rita Ribes Pereira e do artista Marcel Duchamp. As relações estabelecidas para compreender o campo das artes visuais na contemporaneidade estão no pensamento de Arthur Danto eNicolas Bourriaud. Este trabalho dialoga com o campo do ensino da arte através das reflexões realizadas por Ana Mae Barbosa, Jochen Dietrich, Ana Elisabete Lopes, Mirian Celeste Martins e Lucia Pimentel.
Resumo:
EXTRACT (SEE PDF FOR FULL ABSTRACT): This is a previous presentation of what has been observed in points spread in Mexico. The existing data amount is large enough that an atlas was given out in 1977. This atlas has information which goes back to the beginning of the country. The original data sets from which this atlas was issued exist in a variety of storage forms ranging from simple paper blocks up to books and magnetic tapes.
Resumo:
We describe the food habits of the Sowerby’s beaked whale (Mesoplodon bidens) from observations of 10 individuals taken as bycatch in the pelagic drift gillnet fishery for Swordfish (Xiphias gladius) in the western North Atlantic and 1 stranded individual from Kennebunk, Maine. The stomachs of 8 bycaught whales were intact and contained prey. The diet of these 8 whales was dominated by meso- and benthopelagic fishes that composed 98.5% of the prey items found in their stomachs and cephalopods that accounted for only 1.5% of the number of prey. Otoliths and jaws representing at least 31 fish taxa from 15 families were present in the stomach contents. Fishes, primarily from the families Moridae (37.9% of prey), Myctophidae (22.9%), Macrouridae (11.2%), and Phycidae (7.2%), were present in all 8 stomachs. Most prey were from 5 fish taxa: Shortbeard Codling (Laemonema barbatulum) accounted for 35.3% of otoliths, Cocco’s Lanternfish (Lobianchia gemellarii) contributed 12.9%, Marlin-spike (Nezumia bairdii) composed 10.8%, lanternfishes (Lampanyctus spp.) accounted for 8.4%; and Longfin Hake (Phycis chesteri) contributed 6.7%. The mean number of otoliths per stomach was 1196 (range: 327–3452). Most of the fish prey found in the stomachs was quite small, ranging in length from 4.0 to 27.7 cm. We conclude that the Sowerby’s beaked whales that we examined in this study fed on large numbers of relatively small meso- and benthopelagic fishes that are abundant along the slope and shelf break of the western North Atlantic.