1,720,977 research outputs found
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
Seed Ecology In Montane Forests On O‘ahu: Implications For Conservation
Get PDFHawai‘i is renowned for its unique biota, and for the degree to which that biota is imperiled by extinction. Key threats to the native flora include alien herbivores, the loss of mutualists, and competition with alien species. Ecological restoration on the islands focuses on removing alien ungulates, reducing invasive alien plants, and increasing native diversity and recruitment. Oʻahu is the most populated island and has lost the highest proportion of forest cover compared to other main Hawaiian Islands. Forest communities are dominated by alien plants at lower elevations but retain increasing native diversity at higher elevations. All forest types have lost all native seed dispersers, which may significantly alter the recruitment of native species. Ongoing restoration efforts on Oʻahu, in combination with novel interactions between alien birds and both alien and native plants, provide a unique opportunity to investigate novel interactions and assess the effects of restoration efforts to reduce invasive alien plants and increase the recruitment of native plant species. I conducted three field studies on O‘ahu investigating various aspects of seed ecology. In Chapter 2, I used seed rain traps and vegetation surveys, in three mixed and one native forest community, to investigate the distribution, reproduction, and dispersal of native and alien species adapted for bird dispersal. At all sites, alien seeds were more abundant in the seed rain and more frequently dispersed than native species, even where alien species made up <5% of the vegetation cover. Abundant alien species both in the vegetation and seed rain are among the most invasive alien species in the world. In Chapter 3, I measured and compared the seed rain and vegetation of native and alien bird-adapted species and the wind-dispersed native tree Metrosideros polymorpha in a three-year-old clear-cut surrounded by relatively intact forest to understand whether clear-cutting an invasive tree, Psidium cattleyanum, facilitates native plant regeneration. Two invasive alien understory species, Clidemia hirta and Rubus rosifolius, were the most abundant species in the seed rain in both habitats and the most abundant vegetation in the clear-cut. Seeds of the dominant native tree, Metrosideros polymorpha, were dispersed into the clear-cut, but few seedlings occurred, possibly owing to microsite limitation. In Chapter 4, I investigated the effect of canopy cover on the germination and seedling survival of four common native plant species—Alyxia stellata, Coprosma foliosa, Dianella sandwicensis, and Leptecophylla tameiameiae—in a managed mesic forest. Germination of A. stellata and C. foliosa was positively correlated with canopy cover. Germination of D. sandwicensis, and L. tameiameiae was independent of canopy cover. Invasive alien plants are regenerating more vigorously and more frequently dispersed than natives under current conditions. Two small-seeded alien species, C. hirta and R. rosifolius, are the most prolific invasive aliens in the seed rain and disperse into most forest microsites. Native recruitment is limited in all forest types and native species may benefit from human-mediated dispersal. Seed sowing in appropriate microsites is a potential method for increasing recruitment of common species.Ph.D
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
Flower biology of Hibiscus clayi (Koki‘o ‘ula): Determining the effects of inbreeding on seed set, germination, and growth on ex-situ plants
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High elevation Hawaiian plant communities: implications for conservation under climate change
Get PDFGlobally, subalpine, and alpine plant communities are receiving increasing attention due to disproportionate rapid warming at high altitudes and the resultant shrinking habitat leaving high-altitude specialists with less habitat and nowhere to migrate. Plant communities on tropical high islands, such as the Hawaiian Islands, are predicted to experience rapid climate change, and if increased temperature and/or drought exceed plant species’ current tolerances, species that are unable to adapt or shift ranges, risk extinction. While extensive climate modeling is underway in Hawaiʻi, few studies have assessed the potential impacts of climate change on high elevation vegetation. To address this knowledge gap, I first quantified habitat specialization for 170 plant species using species co-occurrence data from over one thousand plots to rank species’ realized habitat niche breadth using the Jaccard index. This indirect method of estimating species’ potential climatic flexibility uses increasingly available large plant community data sets with output rankings which represent species’ realized habitat niches. The distribution of species along this continuum differed by species’ biogeographic origin, with endemic plant species ranked on the specialist end and non-native plant species ranked on the generalist end. Habitat specialization rankings also differed by number of habitat moisture types, minimum elevation, number of Hawaiian Islands, and life form. Volcanic mountains in Hawaiʻi have distinct treeline ecotones driven by trade wind inversion. During the past fifty years, periods of increased temperature and drought associated with increasingly frequent cloud inversion events have occurred, but little is known about how these climatic changes have influenced treeline vegetation. Vegetation data from 225 plots spanning treelines (1500-2500 m) on Haleakalā and Mauna Loa were used to categorize ecotonal plant communities. Treeline indicator species differ by moisture and temperature variables with common native species important for all types: wet forest (Cheirodendron and Metrosideros trees, ferns), subalpine woodland (Myoporum and Sophora trees), and subalpine shrubland (Vaccinium and Leptecophylla shrubs, native graminoids). The subalpine woodland contains the most habitat generalist indicator species, likely due to high non-native species richness. Moisture best explains the described patterns in plant community composition, with wet canopy evaporation, mean annual precipitation, and aridity index values differentiating between wet forest and subalpine communities. A wider extent of the subalpine zone (i.e., beyond treeline ecotone) was analyzed to further identify commonalities and differences between plant communities on Haleakalā and Mauna Loa volcanoes. I compared plant species richness, cover, and density data from 89 plots. A total of 138 plant species were recorded and over half of these species were non-native (56%) with the remainder being endemic (30%) and indigenous (14%). Gamma diversity differed between volcanoes with one-third found only on Haleakalā, one-third found only on Mauna Loa, and one-third shared. Species richness per plot differed from gamma diversity in that endemic species were more abundant than non-native species for both volcanoes indicating that while many non-natives are present, their populations remain patchy and not yet widespread. Non-native species richness was higher on Haleakalā than Mauna Loa. In general, the subalpine communities are characterized by patchy low-lying (3500/ha) and indigenous Leptecophyllya (>2430/ha) shrubs dominant. I recommend continued monitoring of biotic communities and climate in this sensitive high elevation zone, additional physiological in situ studies for the few native matrix subalpine plant species, stricter non-native species biosecurity and sanitation protocols, wildfire prevention, and improved documentation of the effects of feral ungulates including their ongoing removal.Ph.D
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
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