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Ecology of polyembryonic species with emphasis in Cerrado Biome
No full textThe of more than an embryo per seed, known as polyembryony, and the asexual reproduction
via seed, known as apomixis, are usually associated. The records and importance of these
events have increased in the last decades both for the Angiosperms as a whole and for specific
biomes, as the Cerrado, where sexual reproduction is predominant. Despite these records,
information on the ecology of polyembryonic seeds is still lacking. In this scenario, we aimed
to confirm polyembryony as an indicator of apomixes in woody species of Cerrado and, based
on studies of embryo resource allocation, seed germination, emergency and seedling growth,
try to define the advantages and disadvantages of polyembryony for the ecology of these
species. Out of a 132 species sample, 30.30% presented polyembryony, although only 6.82%
did have the percentage of polyembryonic seeds above 5% and were more readily associated
with apomixes. Among the Melastomataceae, a characteristic Neotropical family very well
represented in the Cerrado, 33.96% of the species presented polyembryony, which
predominated in the tribe Miconieae. Both in the Cerrado as a whole and in the
Melastomataceae in particular, the polyembryony was associated with apomixes, but in the
later, the apomixes was less often associated to higher frequencies of polyembryony. More
specific studies with species of Eriotheca (Malvaceae-Bombacoideae) showed mosaics of
monoembryonic and polyembryonic populations in E. gracilipes and E. pubescens, with
ecological differences between either types of population. Polyembryony did not affected
markedly seed germinability and seedling emergence, but resulted in less homogeneous
processes than the one found in monoembryonic seeds. Resource allocation studies showed
that both embryo and seedling mass decreased with the number of embryos or seedling per
seed. These differences reduced the survival ability of seedlings emerging from
polyembryonic seeds but, on the other hand, increased the survival chances of at least one of
the seedlings from these seeds (seed individual survival). In Handroanthus chrysotrichus
(Bignoniaceae), some of the putative advantages of polyembryony, as allee effect and bet
hedging could be experimentally evaluated. Polyembryony was clearly correlated with the
occurrence of apomixis and the results presented here showed that both processes can be
important factors for the persistence and distribution of plant species in the Cerrado Biome.Fundação de Amparo a Pesquisa do Estado de Minas GeraisDoutor em Ecologia e Conservação de Recursos NaturaisA ocorrência de mais de um embrião por semente, conhecida como poliembrionia, e a
reprodução assexuada via semente, conhecida como apomixia, são processos comumente
associados. Os registros e a importância destes eventos vêm aumentando nas últimas décadas,
tanto entre as Angiospermas como um todo quanto em biomas como o Cerrado, reconhecido
como um bioma onde a reprodução sexuada é predominante. Apesar destes registros, existem
ainda poucas informações sobre a ecologia das sementes poliembriônicas. Nesse cenário,
objetivou-se confirmar a poliembrionia como indicador de apomixia em espécies arbóreas e
arbustivas de Cerrado e, a partir de estudos alocação de recursos entre embriões, de
germinação de sementes, emergência e crescimento de plântulas, tentar definir quais são as
vantagens e desvantagens da poliembrionia para a ecologia das espécies. De um total de 132
espécies amostradas, 30,30% apresentaram poliembrionia, embora somente 6,82%
apresentem porcentagens de sementes poliembriônicas acima de 5% e sejam mais diretamente
associadas a presença de apomixia. Entre as melastomatáceas, uma família característica dos
Neotrópicos e muito bem representada no Cerrado, 33,96% das espécies apresentam
poliembrionia, com predominância em espécies da tribo Miconieae. Nos dois grupos
amostrados, a poliembrionia foi associada à espécies apomíticas, poliplóides e com amplo
padrão de distribuição, mas entre as Melastomataceae, a apomixia nem sempre estava
associada a freqüências altas de poliembrionia. Estudos mais específicos com espécies de
Eriotheca (Malvaceae-Bombacoideae) mostraram a ocorrência de mosaicos de populações
monoembriônicas e poliembriônicas em E. gracilipes e E. pubescens, com diferenças na
ecologia dos diferentes tipos de populações. A poliembrionia afetou pouco a germinabilidade
e emergência das sementes, mas produziu um processo menos homogêneo que aquele das
sementes monoembriônicas. Os estudos de alocação mostraram que a massa dos embriões
diminuiu com o número de embriões por semente, fator que se repetiu com a massa individual
de cada plântula. Estas diferenças de alocação reduziram a capacidade de sobrevivência das
plântulas de sementes poliembriônicas, mas de uma maneira geral, aumentaram as
possibilidades de sobrevivência de alguma das plântulas destas sementes. Em Handroanthus
chrysotrichus (Bignoniaceae) algumas das vantagens da poliembrionia como a ocorrência de
allee effect e bet hedging puderam ser avaliadas experimentalmente. A poliembrionia foi
fortemente correlacionada com a presença de apomixia e os resultados mostram que a
presença de poliembrionia e apomixia podem ser fatores importantes para a persistência e
distribuição de espécies no Bioma Cerrado
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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