880 resultados para New Knowledge


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The RMR system is still very much applied in rock mechanics engineering context. It is based on the evaluation of six weights to obtain a final rating. To obtain the final rating a considerable amount of information is needed concerning the rock mass which can be difficult to obtain in some projects or project stages at least with accuracy. In 2007 an alternative classification scheme based on the RMR, the Hierarchical Rock Mass Rating (HRMR) was presented. The main feature of this system was the adaptation to the level of knowledge existent about the rock mass to obtain the classification of the rock mass since it followed a decision tree approach. However, the HRMR was only valid for hard rock granites with low fracturing degrees. In this work, the database was enlarged with approximately 40% more cases considering other types of granite rock masses including weathered granites and based on this increased database the system was updated. Granite formations existent in the north of Portugal including Porto city are predominantly granites. Some years ago a light rail infrastructure was built in the city of Porto and surrounding municipalities whi h involved considerable challenges due to the high heterogeneity levels of the granite formations and the difficulties involved in their geomechanical characterization. In this work it is intended to provide also a contribution to improve the characterization of these formations with special emphasis to the weathered horizons. A specific subsystem applicable to the weathered formations was developed. The results of the validation of these systems are presented and show acceptable performances in identifying the correct class using less information than with the RMR system.

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[Excerpt] Purine nucleobases are fundamental biochemicals in living organisms. They have been a valuable inspiration for drug design once they play several key roles in the cell.1 To the best of our knowledge, reported routes to 8-aminopurines are still scarce due to the difficulty in introducing amino groups in this position of the purine ring. Here we report a novel, inexpensive and facile synthetic method to generate N3,N6-disubstituted-6,8-diaminopurines. In our research group, a number of substituted purines have been obtained from a common imidazole precursor, the 5-amino-4-cyanoformimidoyl imidazole 1. Recently, a comprehensive study on the reactivity of imidazoles 1 with nucleophiles under acidic conditions led us to develop experimental methods to incorporate primary amines into the cyanoformimidoyl group.2 (...)

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[Excerpt] Purine nucleobases are essential biomolecules in living organisms. Playing several key roles in the cell, they have been a significant inspiration for drug design.1 Benzimidazole nucleus is an important pharmacophore in the development of molecules with pharmaceutical or biological interest. Benzimidazoles have been reported to display significant pharmacological activities such as antiulcer, antifungal, antiparkinson, anticancer and antibiotic.2 Fused structures incorporating these two scaffolds might be important for medicinal chemistry and, to the best of our knowledge, there are no reports of these systems in the literature. In particular, benzo[4,5]imidazo[2,1]purines seem to be novel and must be important target molecules in the heterocyclic synthesis. (...)

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Tese de Doutoramento em Ciências da Saúde

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Tese de Doutoramento em Ciências (área de especialização em Química)

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Distribution records of poorly-known species are currently the most explored theme in the Brazilian seabird literature. If properly evaluated, this kind of information can improve our knowledge on distribution, migration and status of occurrence of these species. In this note we present new records for six species of poorly-known seabirds in the Brazilian coast, reviewing distribution records and defining their status of occurrence in the country. We consider Chionis albus (Gmelin, 1789) a pseudo-vagrant in Brazil and define its status as a scarce seasonal visitor from southern South America. We present the first records of Leucophaeus atricilla (Linnaeus, 1758) for Trindade Island, and of Leucophaeus pipixcan (Wagler, 1831) for the state of Rio Grande do Sul, and determined that the former is a vagrant in eastern Brazil and the latter a vagrant across the country. Anous stolidus (Linnaeus, 1758) is a vagrant in southernmost Brazil. We were unable to determine if records of Chlidonias niger (Linnaeus, 1758) for Brazil and southern South America refer to vagrancy or pseudo-vagrancy. Additionally, we verified the occurrence of breeding individuals of Anous minutus Boie, 1844 on Martin Vaz Island and confirmed that there is no evidence of breeding on neighboring Trindade Island.

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The present study is a further contribution to the systematic knowledge of the shallow water marine ostracodes from the Brazilian oceanic islands. A total of 14 species belonging to 10 genera and eight families is herein identified. One new genus and species are described and illustrated: Berguecythere insularis gen. nov., sp. nov. In addition to this new taxon, the abundant species Loxocorniculum tricornatum Krutak, 1971, widely distributed in recent sediments in the Gulf of Mexico, Caribbean, north and northeast of Brazil and the Rocas Atoll, along with the cosmopolitan tropical ostracode Triebelina sertata Triebel, 1948, were also identified at specific level. The remaining 11 species were left at the genus level, and should provide new species. Ecological, zoo- and paleozoogeographical aspects were also briefly discussed.

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Two new species of Xestoleberididae: Xestoleberis brasilinsularis sp. nov. and Xestoleberis machadoae sp. nov., both endemic to Archipelago of São Pedro and São Paulo, are described. The record of these shallow marine waters species from Brazilian oceanic islands represents an important contribution to the knowledge of the evolutionary history the species inhabit areas.

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In this paper the authors refere Philometra lateolabracis Yamaguti, 1935 for the first time from the Atlantic Ocean also as a new host record. They report the rpesence of one male of diminished dimensions, found in close relationship with the females of Ph. lateolabracis; as the male of this species is unknown, they admit the possibility of this small nematode be the male of this species.

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This paper publishes the hitherto unpublished correspondence between Allyn Abbott Young’s biographer Charles Blitch and 17 of Young’s former students or associates. Together with related biographical and archival material, the paper shows the way in which this adds to our knowledge of Young’s considerable influence as a teacher upon some of the twentieth century’s greatest economists. The correspondents are as follows: James W Angell, Colin Clark, Arthur H Cole, Lauchlin Currie, Melvin G de Chazeau, Eleanor Lansing Dulles, Howard S Ellis, Frank W Fetter, Earl J Hamilton, Seymour S Harris, Richard S Howey, Nicholas Kaldor, Melvin M Knight

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Intrarenal neurotransmission implies the co-release of neuropeptides at the neuro-effector junction with direct influence on parameters of kidney function. The presence of an angiotensin (Ang) II-containing phenotype in catecholaminergic postganglionic and sensory fibers of the kidney, based on immunocytological investigations, has only recently been reported. These angiotensinergic fibers display a distinct morphology and intrarenal distribution, suggesting anatomical and functional subspecialization linked to neuronal Ang II-expression. This review discusses the present knowledge concerning these fibers, and their significance for renal physiology and the pathogenesis of hypertension in light of established mechanisms. The data suggest a new role of Ang II as a co-transmitter stimulating renal target cells or modulating nerve traffic from or to the kidney. Neuronal Ang II is likely to be an independent source of intrarenal Ang II. Further physiological experimentation will have to explore the role of the angiotensinergic renal innervation and integrate it into existing concepts.

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The heat- and odour-producing genus Arum (Araceae) has interested scientists for centuries. This long-term interest has allowed a deep knowledge of some complex processes, such as the physiology and dynamics of its characteristic lure-and-trap pollination system, to be built up. However, mainly because of its large distributional range and high degree of morphological variation, species' limits and relationships are still under discussion. Today, the genus comprises 28 species subdivided into two subgenera, two sections and six subsections. In this study, the phylogeny of the genus is inferred on the basis of four plastid regions, and the evolution of several morphological characters is investigated. Our phylogenetic hypothesis is not in agreement with the current infrageneric classification of the genus and challenges the monophyly of several species. This demonstrates the need for a new infrageneric classification based on characters reflecting the evolution of this enigmatic genus. To investigate the biogeography of Arum deeply, further spatiotemporal analyses were performed, addressing the importance of the Mediterranean basin in the diversification of Arum. Our results suggest that its centre of origin was the European-Aegean region, and that major diversification happened during the last 10 Myr.