1,720,997 research outputs found
Colonization and adaptations of Ficus in Taiwan
No full text臺灣島約在200萬年前形成，此論文研究臺灣的榕屬植物，探討物種於新興島嶼的拓殖和島嶼環境對物種分佈的影響。榕屬植物其互利共生的授粉小蜂擅於長途播遷，榕屬植物的隱頭花序──榕果──也被許多種高效率的種子傳播者取食。在此論文中，我們建立一套屬內通用的基因標記，以同一套分子標記分析不同物種。接著，利用四個榕樹種分析臺灣的遺傳結構。其中雀榕在溫暖的南臺灣呈現明顯的遺傳分化，顯示此高度變異種類可能處於生態種化的初期；而另有徵兆顯示在南臺灣的稜果榕正在進行選汰過程。在更大的尺度下，此研究顯示微衛星體ＤＮＡ資料，特別是R統計量，可針對榕屬的親緣地理學提供有用的理解，在許多的物種上，亞洲大陸似乎提供了單一的遺傳背景，儘管在族群間有強烈的基因分化；然而在幹花榕是由菲律賓拓殖而來，未值測到任何與大陸的基因交流。最後，針對Ｘ種榕樹於臺灣南北兩處的物候調查顯示，唯有可頻繁結果的榕樹種可在此島建立族群。本研究為榕樹在島嶼環境的反應開啟了一系列的觀點。The Island of Taiwan appeared some two million years ago. We investigated the Ficus species of Taiwan in order to understand how the island was colonized and how insular conditions affected the colonizing species. Genus Ficus is characterized by its mutualistic association with highly dispersive pollinating wasps. Further figs, the closed inflorescences of Ficus, are consumed by a large number of highly efficient seed dispersers. We developed a set of portable genetic markers in order to analyze several species using a single set of markers. We then analyzed genetic structuring within Taiwan in a set of four species. One species presented clear genetic differentiation in the warm south Taiwan, suggesting the possibility of incipient ecological speciation in a highly dispersive species. Another species presented indications of ongoing selective processes also in south Taiwan. On a broader scale we show that microsatellite data and notably R statistics provide useful insights into Ficus phylogeography. In three species, continental Asia seems to correspond to a single genetic background despite strong genetic differentiation among populations. For Ficus variegata, we show that it colonized Taiwan from the Philippines and we detect no trace of gene flow from the continent. An investigation of Ficus reproductive phenology suggests that only species producing frequent fig crops have established on the island. This work opens up a series of perspectives on the response of Ficus to insular conditions
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
The figs of winter: Seasonal importance of fruiting fig trees (Ficus: Moraceae) for urban birds
No full textBain, Anthony
No full textSee entry in Marshall County, volume 1, page 13: https://digital.archives.alabama.gov/digital/collection/voter1867/id/285
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
- …
