981 resultados para McKay Correspondence
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A ideia de que as Matemáticas de Portugal (e de Espanha) atravessaram, depois de um período áureo nos Descobrimentos, um longo deserto onde não foi possível florescerem Mestres, nem escolas, nem cultura científica, nem investigação de relevo foi, durante muito tempo, reiteradamente veiculada, inclusivé através de alguns dos nossos mais referenciados historiadores da Matemática, como é o caso de Gomes Teixeira ou de Rey Pastor. Mas a verdade é que o estudo da História das Matemáticas em Portugal tem, na última década, vivido um interesse crescente onde sobressaem, em particular, uma leitura menos enviesada sobre, por exemplo, o papel educativo dos Jesuítas ou a publicação das obras completas de Pedro Nunes. Está-se assim a contribuir para uma compreensão mais completa da História geral de Portugal, de que a História da Ciência e da Cultura faz parte. José Anastácio da Cunha (1744-1787) foi figura de proa no século XVIII português. Sabíamo-lo matemático que, sem nunca ter saído de Portugal, havia sido capaz de antecipar, em mais de 50 anos, os esforços de matemáticos franceses e alemães para fundar a Matemática com rigor. Sabíamo-lo também autor de uma vasta e diversificada obra de inegável importância matemática mas, igualmente, autor de textos poéticos. Agora, com o projecto que denominámos de MAT2, centramo-nos em José Anastácio da Cunha e pretendemos, se possível, ir ainda mais além. Partimos de uma descoberta, árdua mas com final feliz, em um Arquivo de família: o da Casa de Mateus. Sentimo-nos, com esta “sorte”, privilegiados e gratos por nos ter sido gentilmente concedido o acesso a um vasto conjunto de documentos únicos (diários de viagens, notas de aulas e correspondência) que incluem memórias autógrafas e inéditas de Anastácio da Cunha. Organizámo-nos, cientes do trabalho árduo que temos pela frente, multi e interdisciplinarmente englobando a Matemática (nas suas múltiplas especializações) e a História (incluindo a da Matemática) mas também contando com a Física, a Informática, os estudos militares ou a Arquivística e as Humanidades; reunimos académicos, mais e menos veteranos, com investigadores jovens e juntámos valências nacionais e estrangeiras. No presente artigo daremos conta do percurso trilhado, até agora, pelo projecto MAT2.
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This study describes the diversity and the subsistence fishing territoriality of traditional populations of a village Ashaninka and two Kaxinawá living at the margins of Breu River (Brasil/Peru). In general, samplings in the dwellings were carried out late in the afternoon, as the fishermen arrived in the village. The data were analysed in an exploratory way through the index of pondered dominance (ID%), by analysis of variance and by a correspondence analysis in order to determine the associations of the fish species and the fishing spots between the villages of the Indigenous Reserve. The results of the analysis of variance demonstrated that differences exist between the fish diversities of the catches. However, post-hoc tests only detected differences in diversities between the hand fishhook and the other fishing gears (bow and arrow, castnets and rotenone tingui). Although the use of bow and arrow resulted in a low capture (Kg), this fishing strategy is associated with a high fishing diversity, in terms of number of species. These results demonstrate that there is no overlap in the frequency of the visits to the fishing spots between the Ashaninka and Kaxinawá populations. This pattern is the same found for the correspondence analysis for the fish species, which describes the relationship between the deep pools environments exploited by the fishermen Ashaninka and Kaxinawá of Mourão. These ethnic populations still continue to maintain a strong cultural and cosmological tradition, with their territories defined in an informal way of the upper Juruá area.
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Natural regeneration and structure and their relationship to environmental variables were studied in three sections of a gallery forest, in Eastern Mato Grosso, Brazil (14º43′S and 52º21′W). The assumption was that natural regeneration is constrained by environmental determinants at all stages of development of the tree community. The objective was to analyse the forest structure and to verify the relationship between species distribution and abundance at different stages of regeneration and environmental variables. In each section, 47 contiguous (10x10m) permanent plots were established to sample trees (gbh≥15cm), following a systematic design. Seedlings (0.01 to 1m height), saplings (1.01 to 2m) and poles (from 2.01m height to gbh<15cm) were sampled in sub-plots of 1x1m, 2x2m and 5x5m, respectively. In each plot, soil properties, gaps projection, bamboos, rocky cover, declivity and depth of ground watertable were determined. The relationships between the environmental variables with trees and seedling communities were assessed by canonical correspondence analysis. In spite of the sections being near to each other, they presented large differences in floristics, structure and site conditions. The forest soil presented a low cation exchange capacity and a high level of Al saturation. The occurrence of bamboos and gaps and the depth of ground watertable limited the occurrence of poles and trees. The high degree of structural heterogeneity for each regeneration category was related primarily to a humidity gradient; but soil fertility (Ca+Mg) was also a determinant of seedling and sapling communities.
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We evaluated diversity and distribution of fish species in two habitats: flooded forest and open water of lakes of Rio Negro. Each of four lakes within the Anavilhanas Archipelago was sampled three times from 2009-2010. Species diversity generally was higher in flooded forests and at night, according to correspondence analysis. Predators were most active at night, but showed no preference between the flooded forest and open water habitats. Omnivores, filter feeders, and detritivores were most active during the day.
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Dissertação de mestrado em Educação Especial (área de especialização em Dificuldades de Aprendizagem Específicas)
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The determination of the climatic potential of tourism to Tbilisi (the capital of Georgia) into the correspondence with that frequently utilized in other countries of the “tourism climate index” is carried out.
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The taxonomic composition, observed and estimated species richness, and patterns of community structure of arboreal spider assemblages in eleven sites surrounding the "Banhado Grande" wet plain in the state of Rio Grande do Sul, Brazil, are presented. These sites represent three different vegetational types: hillside (four sites), riparian (five sites) and flooded forests (two sites). The spiders were captured by beating on foliage and "aerial litter". A sample was defined as the result of beating on twenty bushes, tree branches or "aerial litter" clusters, which roughly corresponds to one-hour search effort per sample. Fifty five samples (five per site) were obtained, resulting in an observed richness of 212 species present as adult or identifiable juveniles. The total richness for all samples was estimated to be between 250 (Bootstrap) to 354 species (Jackknife 2). Confidence intervals of both sample and individual-based rarefaction curves for each vegetation type clearly indicated that flooded forest is the poorest vegetation type with respect to spider species richness, with hillside and riparian forests having a similar number of species. The percentage complementarity between the eleven sites indicated that all sites contain a distinct set of species, irrespective of their vegetation types. Nevertheless, the spider assemblages in riparian and hillside forests are more similar with respect to each other than when compared to flooded forest. Both cluster and nonmetric multidimensional scaling analyses showed no strong correspondence between the spider arboreal fauna and the three vegetation types. Moreover, a Mantel test revealed no significant association between species composition and geographic distance among sites.
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In the Cerrado vegetation, where the seasonal is well defined, rainfall has an important role in controlling the flow of streams and consequently on the structure of macroinvertebrates community. Despite the effects of rainfall associated with seasonality are well studied, little is known about the effects of stochastic rains on the community. In the present study we evaluated the structure and faunal composition of four first-order streams in Central Brazil during the dry season in two years, with and without stochastic rains. Community sampling was done by colonization of boards of high density polyethylene (HDPE), removed after one month submerged in streams. Analysis of Variance (ANOVA) performed indicated no difference in rarefied richness between the two periods, different from numeric density of organisms that was higher in the period without disturbance; moreover, the Detrended Correspondence Analysis (DCA) revealed differences in faunal composition between the two periods. Our results indicate that stochastic rainfall is an important factor in structuring the macroinvertebrates community in studied region.
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We describe an equivalence of categories between the category of mixed Hodge structures and a category of vector bundles on the toric complex projective plane which verify some semistability condition. We then apply this correspondence to define an invariant which generalises the notion of R-split mixed Hodge structure and compute extensions in the category of mixed Hodge structures in terms of extensions of the corresponding vector bundles. We also give a relative version of this correspondence and apply it to define stratifications of the bases of the variations of mixed Hodge structure.
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We study the incentives of candidates to enter or to exit elections in order to strategically affect the outcome of a voting correspondence. We extend the results of Dutta, Jackson and Le Breton (2000), who only considered single-valued voting procedures by admitting that the outcomes of voting may consist of sets of candidates. We show that, if candidates form their preferences over sets according to Expected Utility Theory and Bayesian updating, every unanimous and non dictatorial voting correspondence violates candidate stability. When candidates are restricted to use even chance prior distributions, only dictatorial or bidictatorial rules are unanimous and candidate stable. We also analyze the implications of using other extension criteria to define candidate stability that open the door to positive results.
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The first case of Kala-azar in Colombia was discovered in Soledad, S. Vicente do Chucuri, Dept. Santander, by Gast-Galvis who viscerotomized a three year old girl deceased in December, 1943. In 1944, fifty-three Phlebotominae were collected in the chicken pen of the girl's house, two new species included. Mangabeira helped by A. Gast Galvis, Juan Antonio Montoya and E. Osorno Mesa, collected some Phlebotomus in that country. The geographical distribution of the species of Phlebotomus collected in Colombia (P. abonnenci, P. camposi, P. columbianus, P. dubitans, P. gasti, P. montoyai, P. saulensis, P. serranus, P. triramulus) and two species of Brumptomyia (B. beaupertuyi and b mesari), are included. our description of the male P. columbianus is based on some specimens found in association with females. However, doubts exist about such association of sexes. There is no correspondence between the length of the spicules and the ducts of spermathecae. Besides, the specimens were not obtained by raising. The following new species are described and compared with previously known ones: a) Phlebotomus gasti sp. n. differs from the other species by a protruding tubercle in the gubernaculum. It has also fewer setae in the tuft of the basistyle, a different length of the inferior gonapophyses, and a differently shaped clasper. b) Phlebotomus dubitans sp. n. differs from P. walkeri and P. deanei (according to personal information from O. Theodor, who examined the types, they are identical to P. williamsi and P. sericeus respectively), mainly because these species have the inferior gonapophyses larger than the basistyle and fewer setae in the basistyle. P. evandroi is separated by the shape of the claspers and by the tuft of setae of the basistyle. P. marajoensis is the closest relative to P. dubitans. There is a possibility of their being synonymous. On the other hand, they can be differentiated by the existence of three extra distal spines in P. marajoensis. There is also a difference in their palpal indexes: for marajoensis I - II - IV - III - V, and for dubitans I - IV (III - II) - V. We notice, too, that the inferior gonapophyses in P. marajoensis is a little shorter. P. marajoensis has a long seta in the basistyle (clearly shown in the original drawing), not found in the new species. c) Phlebotomus montoyai sp. n.: The closest relatives are P. noguchii, P. peruensis, P. pescei, P. quinquifer and P. rickardi. They differ from the new species by the number and length of the setae of the basistyle tuft which are more numerous and longer in the new species. The shapes of their claspers are also different. Other differences are: the basal portion of the basistyle in P. noguchii is very wide (in montoyai it is narrower); the intermediate spine of the dististyle is located on a protruding tubercle ( in the new species there is hardly a tubercle); the spicules are long, and the inferior gonapophyses is longer than the basistyle. P. quinquifer and P. rickardi have a shorter dististyle and narrower wings, with different venation. The main difference, however lies, in the M4, which ends almost at the level of the junction of M1 with M2 (in P. montoyai the M4 ends far behind). In P. peruensis and P. pescei the intermediary spine of the dististyle is closer to the distal spine than to the basal one, whereas in the new species it is situated between the two pairs. Their inferior gonapophyses is longer than the basistyle. d) Brumptomyia mesai sp. n. - Closest relatives are: B. hamatus, B. pentacanthus, B. beaupertuyi which are easily separated from the new species because the tufts of their basistyle have thin and differently shaped hairs. Also their claspers are shaped differently. B. avellari is also easily recognized on account of the twisted aspect of its clasper and because the basal tuft of the basistyle has few setae, B. brumpti tuft of setae arise directly from the basistyle; these setae are stronger than those of the new species. It has 8 blade-like setae located on the inner surface of the distal half, whereas the new species has only six setae. In B. brumpti, there are three median and two terminal spines in the dististyle; in the new species, there are two median and two terminal spines and one between them, which is closer to the two median spines. The comparison with B. galindoi is based in a specimen determined by Fairchild and deposited in the entomological collection of the "Faculdade de Higiene e Saúde Pública da Universidade de S. Paulo". The genitalia of the new species is much shorter, in galindoi the inferior gonapophyses is 0,8 mm long whereas in B. mesai it hardly reaches 0,6 mm. The shape of the clasper and the distribution of its setae are different. The sub-median lamellae, besides being longer in B. galindoi are also longer in comparison with the other parts of the genitalia. The gubernaculum of the new species is longer, thinner, and more pointed; in B. galindoi it is shorter and triangular. In the drawing published by Fairchild and Hertig 91947), the basistyle shows 8 blade-like setae on the distal half, whereas in the new species only six are found.