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Análise comparativa de vegetação lenhosa do ecossistema campina na Amazônia brasileira
Get PDFAmazonian campinas are sclerophytic vegetation occurring in white sand soils. Although in the beginning they were just mentioned for the rio Negro basin, it is now know that the campinas are widely distributed in the Amazon and some other areas of Tropical America. Amazonian campinas occur as enclaves in areas with dominated by other vegetation types such as rain forests, savannas or campinarana forests. The sandy soils colonized by campinarana plants could be of different origins, such as: a) beds of ancient bodies of water that dry ; b) the sandy profiles derived from the erosion of sandstones from the Guiana Shield or the Brazilian Shield, and; c) ancient sand dunes of eolian origin. This present thesis is aiming to describe and compare from the floristic and phytosociologic point of view, nine Amazonian campinas. Only arboreal and shrubby species with diameter at breast height (DAP) > 5 cm were studied. The nine campinas studied contained, 252 species belonging to 121 genera and 44 families. The families of greatest floristic abundance were Fabaceae, Mytaceae, Rubiaceae, Clusiaceae, Malpighiaceae, and Annonaceae. The genera of most importance were Clusia, Emmotum, Pagamea, Tapirira, Eugenia, Matayba, Myrcia and Ouratea. The nine sampled areas exibited a high proportion of unique species: 72.6% of the species were just registered in one of the campinas. The high proportion of exclusive species resulted in a great floristic comparative distance among the campinas (Jaccard distance ranging from 0.471 to 0.942). In contrast, seven species (2.8% of total) occurred in more than five campinas. These species have wide neotropical distribution and occur in different physiognomies: Humiria balsamifera Aubl., Emmotum nitens Miers, Pagamea guianensis Aubl., Tapirira guianensis Aubl., Byrsonima crassifolia (L.) Kunth., Ouratea spruceana Engl. e Alchornea discolor Poepp. The analysis of the species distribution together with the floristic similarity and MDS analysis have found some phytogeographic patterns for the Amazonian campinas, such as: a) great floristic afinity among Amazonian campinas and the Guiana Shield vegetation and Venezuela-Colombia Llanos; b) campinas in contact with Amazon basin and Brazilian Shield, like the Serra do Cachimbo ones, show greater influence from the Cerrado vegetation; c) campinas from eastern Amazon has shown greater influence from the Guiana and Brazilian Shield floras; d) Low afinity between the Amazonian campinas and restinga vegetation from the Atlantic cost; e) Amazonian campinas from the Brazilian western extreme, like Cruzeiro do Sul (Acre), are significantly different from the other ones.
The results of this work reinforce the need of biodiversity conservation programs for the Amazonian campinas due to the great floristic divergence observed among them, large endemic potential and its occurrence on restricted isolated spots.As campinas amazônicas são formações vegetais esclerófilas que se desenvolvem em solos de areia branca. Apesar de inicialmente citadas apenas para a bacia do Rio Negro, sabe-se atualmente que as campinas estão amplamente distribuídas na Amazônia e em outras áreas da América Tropical. As campinas ocorrem como enclaves em áreas com matriz de floresta ombrófila, cerrado ou campinarana. Os substratos arenosos colonizados pelas plantas de campina podem ser de diferente natureza, tais como: (a) leitos de antigos corpos de água que secaram, (b) perfis arenosos oriundos da decomposição de arenitos do Escudo Guianense e do Escudo Brasileiro, e (c) antigas dunas arenosas de origem heólica. O presente trabalho teve como objetivo descrever e comparar, do ponto de vista florístico e fitossociológico, nove campinas na Amazônia Brasileira. Foram estudadas apenas as espécies arbóreas e arbustivas com diâmetro na altura do peito (DAP) 5 cm. Foram registradas, nas nove campinas estudadas, 252 espécies pertencentes a 121 gêneros e 44 famílias. As famílias de maior riqueza florística foram Fabaceae, Myrtaceae, Rubiaceae, Clusiaceae, Malpighiaceae e Annonaceae. Os gêneros de maior importância foram Clusia, Emmotum, Pagamea, Tapirira, Eugenia, Matayba, Myrcia e Ouratea. As nove campinas amostradas exibiram uma alta proporção de espécies exclusivas: 72,6% das espécies foi registrada apenas em uma das campinas. A alta proporção de espécies exclusivas resultou em grande distância florística entre as campinas estudadas (distância de Jaccard variando de 0,471 a 0,942). Em contraste, sete espécies (2,8% do total) ocorreram em mais de cinco campinas. Estas espécies, de ampla distribuição neotropical e de ocorrência em diferentes fisionomias, são: Humiria balsamifera Aubl., Emmotum nitens Miers, Pagamea guianensis Aubl., Tapirira guianensis Aubl., Byrsonima crassifolia (L.) Kunth., Ouratea spruceana Engl. e Alchornea discolor Poepp. A análise de distribuição das espécies, juntamente com análises de similaridade florística e de ordenamento MDS (Escalonamento multi-dimensional não-métrico) indicam alguns padrões fitogeográficos para as campinas, tais quais: (a) grande afinidade florística entre as campinas amazônicas e a vegetação do Escudo Guianense e dos Llanos Venezuelanos/Colombianos; (b) campinas no contato da bacia amazônica com o Escudo Brasileiro – como as da Serra do Cachimbo - apresentam maior influência da vegetação do cerrado; (c) campinas do leste
amazônico apresentam influência mista das floras do Escudo Guianense e do Escudo Brasileiro; (d) baixa afinidade da flora das campinas com a da Restinga Atlântica; (e) campinas do extremo oeste da Amazônia brasileira – como a de Cruzeiro do Sul (Acre) - são altamente diferenciadas das demais. Os resultados aqui apresentados reforçam a necessidade de programas de conservação da biodiversidade das campinas amazônicos, dada a alta diferenciação florística observada entre elas, a grande concentração de endemismos e sua ocorrência em manchas restritas e isoladas
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reproductive biology of two bombacaceous trees in the Brazilian Central Amazon
Get PDFStudies were carried out on the reproductive biology of two bombacaceous trees (Pseudobombax munguba and Ceiba pentandra) which occur in the seasonally flooded areas of the white-water river basins ('varzea') in the Amazon region. The unique pollinator of P. munguba, which has nectarless flowers, is the large-sized phyllostomid bat Phyllostomus hastatus. In contrast, the flowers of C. pentandra are visited by a wide range of nocturnal (bats, marsupials, night-monkeys, hawk moths) and diurnal (bees, wasps, hummingbirds) animals, but only the phyllostomid bats, especially Phyllostomus hastatus and Phyllostomus discolor, play a relevant role in the pollination of this mass-flowering species. Both species appear to be self-incompatible since hand self-pollinated flowers always abscised 5-8 days after pollination, whereas a proportion of cross-pollinated flowers (20-29% in P. munguba; 17% in C. pentandra) formed fruit. However, analysis of fixed pistils using fluorescence microscopy revealed that in both species the self-pollen germinated normally on the stigma and the self-pollen tubes penetrated the ovules at the same rate as the cross-pollen tubes. Mixed-pollinated flowers (self- plus cross-pollen on the stigma) also set some fruits (9-14% in P. munguba; 9% in C. pentandra). Paternity analyses using isozyme genetic markers indicated that fruits resulting from controlled mixed-pollinations set a few selfed seeds (range of 0-28% in P. munguba; ca 2% in the studied tree of C. pentandra). The multilocus estimate of the outcrossing rate (tm) was calculated for P. munguba using data from two isozyme loci of 29 parent trees and 728 progenies. The population outcrossing estimation was high (tm = 0.948) suggesting that the breeding population is large and the level of inbreeding (both uniparental and biparental) is very low. The proportion of selfed-seeds produced by two neighbouring C. pentandra trees, which flowered simultaneously, was estimated using isozyme genetic markers at 9% and 28% respectively. It is considered that a high level of genetic load is the main factor responsible for the self-sterility and the predominant outcrossing mating system observed in both species. The number of lethal equivalents per zygote estimated for each was high: average of 13.8 (minimum 6.4) in the P. munguba population, and 12.3 for the single assessed individual of C. pentandra
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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