1,720,987 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
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
Effects of UV and Elevation on Flavonoid Production in Juvenile Landrace Maize Leaf Tissue
Get PDFMany plant populations are locally adapted to conditions that vary across the landscape. At the maize center of diversity in Southern Mexico, maize landraces are locally adapted to the environments in which they grow. Maize from higher elevation zones has been selected under conditions of greater exposure to UV-B light compared to lower elevation landraces. This could be important as climate change urges farmers to plant varieties from warmer, lower climes at higher elevations with higher UV-exposure. Our goal was to understand the biochemical mechanisms that may maintain high performance under local conditions, and how this biochemistry changes under novel conditions. In this study, we investigated UV-B protective flavonoids produced by maize landraces collected at three elevations (600 m, 1550 m, and 2050 m) and planted in common gardens at 1550 m and 2050 m in Chiapas, Mexico. Using high performance liquid chromatography (HPLC), we examined the presence and quantity of maize leaf flavonoids maysin, quercetin-3-glucoside (q-3-glucoside), and quercetin-3-rutinoside (q-3-rutinoside) produced across 12 maize collections from three elevations (i.e. maize types) and garden locations. Due to results from a previous gene expression study and the likely adaptive importance of UV-B protection, we hypothesized that highland maize may have higher production of certain UV-B protective compounds than lower elevational types, with all types inducing greater production in response to increases in UV-B. Our results demonstrate that increases in elevation increased flavonoid production. This response was similar across maize types from different elevations, although highland types seemed to have a greater induced response. These results may have implications for maize production with climate change since moving of crop populations to higher elevations to address warming may be disrupted by differential UV-B adaptation. Future work could investigate the fitness effects on plants that employ these different flavonoid pathways under higher and lower UV-B conditions to better understand desired chemotypes and their biological consequences.ECOSUROSUA one-year embargo was granted for this item.Academic Major: Evolution and Ecolog
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
Seed and seedling characteristics of chile pepper (Capsicum annuum L.) across a domestication gradient
Get PDFChile peppers (Capsicum annuum L.) are a crop with great importance both economically and culturally across Mesoamerica and beyond. During a time of climate change, the use of this crop species is threatened by rising temperatures and droughts. As such, the sources of genetic diversity found in landrace and wild (C. annuum glabriusculum) accessions are incredibly valuable. Identification of the natural adaptations in landraces and the wild relatives of chiles can facilitate the breeding of biotic and abiotic stress resistance into our crops, better securing their continued use. Seedlings, the most vulnerable stage of the plant life cycle, are an important focus area. Seed and seedling characteristics can be adaptations that assist in the survival of the plant. In this study, we examined seed and seedling characteristics across a domestication gradient in order to better understand the responses in phenotype resulting from the domestication process and the degree to which those changes may be similar across localities of origin. In order to investigate this, C. annuum seeds representing multiple domestication levels from across Mexico were measured using both digital phenotyping methods and physical measurements to quantify traits regarding size and shape of the seeds. Seeds were then planted, and seedlings grown in the greenhouse; they were measured from the time of emergence for phenotypes such as height, cotyledon size, leaf size, and number of leaves. We predicted that both seed and seedling phenotypes would significantly differ across level of domestication and across location of origin. We found that this was true for the majority of phenotypes examined, with certain phenotypes such as cotyledon area and height being especially impacted by domestication. We also found that seed phenotypes were significantly affected by both domestication and location of origin but were more strongly influenced by origin overall. These results inform our understanding of the effects of domestication and local environments on phenotypes, indicating that characteristics influencing seedling vigor may have been selected for during domestication. In addition, this research uncovered landrace and wild accessions of interest that show beneficial phenotypes that are recommended for further examination.The Ohio State University Department of Horticulture and Crop Science, Wilhelm and Eleanor Beckert Scholarship FundGarden Club of America, Katharine M. Grosscup Scholarships in HorticultureThe Ohio State University Honors and Scholars Center, Honors & Scholars Enrichment GrantThe Ohio State University Undergraduate Research & Creative Inquiry, Undergraduate Research Apprenticeship ProgramIntramural research program of the U.S. Department of Agriculture, National Institute of Food and Agriculture, Agriculture and Food Research Initiative [Grant # 2018-67013-27555] to Dr. Kristin MercerNo embargoAcademic Major: Sustainable Plant System
Germination and dormancy of crop-wild sunflower hybrid cross types
Get PDFGene flow from agricultural crops into related wild plant populations can produce viable hybrid offspring with characteristics that differ significantly from those of their wild counterparts. Such crop-wild gene flow, especially in situations involving transgenic crops, has raised concerns about potential losses of genetic diversity, or increases in invasiveness, of wild relatives. The annual sunflower (Helianthus annuus) is an ideal species for studying crop-wild gene flow, the subsequent hybrid generations produced, and the effects on wild populations because the crop and wild types are often found in close proximity, are cross compatible, share pollinators, and are differentiated for important traits that may affect fitness, such as seed dormancy. Outside of cultivation, seeds that germinate in the fall are killed by the winter frost before reproducing, which has lead to the evolution of dormancy in wild populations; their seeds must experience a cold period before germinating in the spring. By contrast, cultivated varieties have been artificially selected to germinate immediately under favorable conditions. Consequently, the degree to which crop-wild hybrids germinate under fall conditions affects the extent to which crop genes may persist in, or introgress into, wild populations. Furthermore, the germination and dormancy characteristics of sunflower seeds, in particular, are due, in part, to the structural characteristics of their achenes (i.e., seeds and hulls). Most of these structures are maternally inherited while the genetics of the embryo involve contributions from both parents. This project determined the rates of germination and dormancy of fifteen crop-wild hybrid sunflower cross types and used microscopy to explore achene characteristics that could influence the differential germination we observed. Maternal effects (e.g., seed covering structures) had significant impacts on germination and dormancy, with crop-produced achenes germinating most readily, followed by those produced on F1 maternal plants, followed by those produced on wild plants.
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The proportion of crop alleles (i.e., nuclear genetics of the embryo) was also important. There was a significant, positive relationship between the proportion of crop alleles and germination in the wild and F1 produced seeds. Microscopy revealed that maternal parent significantly affected achene size, embryo size, and relationships between structures and the micropylar (i.e., pointed) end of the achene. Crop produced achenes were largest and had minimal structural barriers to radicle (i.e, embryonic root) extension. F1 produced achenes were larger and had more substantial barriers which broke down quickly. Wild produced achenes were smallest and had the greatest barriers to radicle extension. Although they differed in size, structural characteristics, and germination rate, seeds produced on crop, F1, and wild maternal parents underwent the same general processes of leading up to germination. These findings suggest that crop alleles and the maternal effects associated with crop-wild hybridization can reduce dormancy, but that this reduction in dormancy may not be significant enough to prevent the introgression of crop alleles into wild populations.OARDC SEEDS Undergraduate Research GrantWilhelm and Eleanor Beckert ScholarshipNo embarg
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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