1,721,075 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
Ecology of rare North American plant species Bartonia paniculata subsp. texana and Platanthera cooperi
No full textBartonia paniculata subsp. texana is an endemic, imperiled plant occurring within the baygalls of the West Gulf Coastal Plain Forested seep (Southern Type; WGCP-FS-ST) habitats of Southeast Texas, which are also considered rare plant communities. Number of individuals and populations of the taxon have both declined by 50% over the last 57 years. Yet, niche preferences within the WGCP-FS-ST of B. paniculata subsp. texana are not characterized, which could enable targeted surveys to identify additional populations within its dwindling habitat. We investigated whether plant communities and environmental conditions within baygalls that support B. paniculata subsp. texana were distinguishable from locations that do not support the taxon. Our results indicate that B. paniculata subsp. texana prefers narrow niches with its baygall habitat. These areas are characterized by identifiable understory vegetation composition (Shannon Index = 1.4, Simpson Index = 0.62), canopy openness (16%), ground cover (live vegetation= 68%, debris= 11%, bare soil= 30%), and soil moisture (23%) as compared to baygalls that do not consistently support the taxon. However, overstory vegetation and soil physicochemical properties between occupied and unoccupied sites were similar. Abstract Chapter 3: Distribution of orchid populations and their fitness is shown to be correlated to the identity, distribution, and abundance of the associated orchid mycorrhizal fungi (OMF), which in turn may be influenced by soil physicochemical characteristics. Roots of plants from larger populations of Platanthera cooperi were dominated by fungi belonging to the Tulasnellaceae (Tul) and hosted Ceratobasidiaceae (Cerato) in low abundances. The soil in these populations had higher concentrations of soil phosphorus (P) and lower concentrations of soil zinc (Zn) in comparison to the smaller populations. We hypothesized that the dominant fungus (LT) in large populations has a competitive advantage at the natural levels of P (295 mg/l) supporting its mycorrhizal association with the orchid. Conversely, we expected suppressed growth of LT under high Zn (41 mg /l) conditions. We cultured isolates representing Tul and Cerato, either individually or in co-culture, on media supplemented with P and/or Zn found in the soils of large and small populations of the orchid. Surface area comparisons after nine days showed that any media in which Zn was manipulated suppresses both fungi yielding smallest surface areas whether cultured individually or together. Highest surface area was recorded for both fungi on media supplemented only with P when they were cultured individually. The two fungi only physically encountered each other when co-cultured on P-supplemented media, where Cerato was dominant over Tul even though its growth was reduced. These results confirm the ability of both Tul and Cerato to occupy similar P niches while suggesting that Cerato may outcompete Tul if they co-occur in the same space. Germination and protocorm formation % after 40 days showed that the Tul leads to high germination and protocorm rates in the natural levels of P and Zn at large populations. Cerato resulted in higher germination %, protocorm formation %, and protocorm to germination raito as compared to Tul. No germination occurred in high Zn treatments. However, fungal DNA sequencing results results revealed the presence of Tul in 62.5 % and Cerato in 37.5 % of the orchid seeds that turned into protocorms in the presence of co-culture of Tul and Cerato. Altogether, our data suggest that although the orchid-OMF-soil interactions are important, the host orchid is likely the more direct determinant of which fungi get recruited into the roots.Embargo status: Restricted until 01/2025. To request the author grant access, click on the PDF link
to the left
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
First evidence of presence and role of endofungal bacteria (EFB) in orchid mycorrhizal fungi (OMF)
No full textPlant-microbial interactions, especially with fungi and bacteria, are
essential for plant existence. Yet, many symbiotic interactions remain undiscovered.
Orchids, one of the largest angiosperm families, depend on orchid mycorrhizal fungi
(OMF). In the study of orchids, the focus has primarily been on OMF. No studies have
documented whether OMF hosts endofungal bacteria (EFB), and what growth-promoting
benefits these EFB might confer. We discovered and documented EFB within OMF using
molecular, fluorescent (FISH), and electron (SEM) microscopy techniques, isolated EFB,
and empirically tested their role in orchid seed germination and protocorm development.
We isolated and identified 9 unique OMF-EFB pairs from the root tissues and protocorms
of Platanthera chapmanii. Two of them were obtained from protocorms and seven from
roots. In the germination tests, germination percentages after 120 days were highest
(66.02%) when OMF containing their EFB were used. When OMF isolates lacking the
endosymbiont EFB were utilized, the germination percentages were lower (54.74%).
Notably, the EFB alone also improved germination (51.35%) compared to the
uninoculated seeds (33.42%). This study marks the first documentation of the presence of
EFB within OMF. And the functional role of these bacteria as mycorrhizal helper bacteria
or as plant growth-promoting bacteria during orchid seed germination
- …
