1,720,985 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
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
Correction: Ser-653-Asn substitution in the acetohydroxyacid synthase gene confers resistance in weedy rice to imidazolinone herbicides in Malaysia.
No full text[This corrects the article DOI: 10.1371/journal.pone.0227397.]
Integrated weed management programs at oil palm plantation -A Survey
No full textWeed control is always regarded as one of the essential operations in the oil palm plantation management. It is the second most costly operation after fertilising. Hence, it is vital to manage noxious weeds’ growth in oil palm plantation areas effectively. Integrated weed management (IWM) refers to a system of sustainable weed management. This system is comprehensive through various control strategies that are undeniably capable of reducing the weeds’ impact to reach economically acceptable levels. The most widely practiced IWM method by plantation companies has been mainly spraying herbicide and cultural practices; many companies are solely depending on the chemical approach for weed control. Our survey indicated that IWM methods always produced lower management costs than non-IWM in FGV Lepar Utara. This indicates that the implementation of IWM could save
on weed control cost up to RM34.00/ha/year. Besides, the cultural practices like mulching (in immature palm) and EFB
applications would reduce weeding cost-efficiently. In addition, the arrangement of fronds, circle raking would reduce weeding cost. Thus, the combination of chemical control and cultural practices was preferred. As a conclusion, it would be appropriate to argue that through IWM implementation, among others, weed populations will be reduced to manageable levels, in addition to the environmental impact that can be reduced significantly instead of adopting an individual weed management practice and reducing the occurrence of herbicide resistance in weed species
Occurrence and management of resistant weed species in FGV plantation in Malaysia : a review.
Get PDFOil palm, currently the world's main vegetable oil crop, is characterized by a large productivity and a long-life span (≥25 years). Weeds are the unwanted plants that grow aggressively, restrict sunlight and compete with desirable plants for nutrients. Weeds population is mainly a mixture of grasses, sedges, broad-leaved weeds plants and ferns in oil palm plantation management. Asystasia gangetica(creeping broad leaf weed), Clidermia hirta (upright woody weed) and Dicranopteris linearis (fern) are amongst noxious weeds under the "must be eradicated "list because of their high tendency to aggressively absorb nutrients and water. In Malaysia alone, since 2004, the use of herbicides has been 67.49% of the total pesticides used. The application of herbicides (e.g. glyphosate, glufosinate, metsulfuron methyl and the recently banned paraquat) in plantations is a common practice even though farmers understand that they are harmful to both applicators and crops if not carefully used. Understanding the mode of herbicidal action is also very useful when diagnosing symptoms of herbicide injuries and to reduce the risk of resistance development in weed populations. Resistance frequently occurs with herbicides that come with very great efficacy to specific weed species, be it acute kill or chronic/slow effect. Herbicide resistance phenomenon in weeds is very depending on the type of herbicides being used (mode of action and selectivity), the period they have been used for, spray dose of the herbicides, the residual effect of the herbicides, the biology and genetic of the weed species being targeted, and existence of other crop management practices that farmers employ. Therefore, weed resistance in Malaysian oil palm plantation is crucial and must be handle with care to avoid unnecessary effect from herbicide resistance
Variation in the phytotoxic activity of Tinospora tuberculata extracts as influenced by solvent type and chemical profile
No full textA study was conducted to evaluate the role of secon-dary metabolites on the allelopathic activity of metha-nol and water extracts obtained from aerial parts of Tinospora tuberculata on seed germination and the radicle and hypocotyl lengths of barnyardgrass. The higher suppressive effects were observed on germina-tion and seedling growth of barnyardgrass, when the methanol extracts of Tinospora tuberculata stem or leaf were applied in comparison to the water extracts. Ultra-fast liquid chromatography analysis confirmed that methanol extracts and leaf extracts contained higher number and amount of chemical compounds than did those of the water extracts and stem extracts respectively. Moreover, the concentrations of 11 iden-tified compounds of the extracts and an equimolar mixture of the chemicals required for 50% growth in-hibition on barnyardgrass germination, radicle and hypocotyle were determined. Trans-cinnamic acid and benzoic acid had the highest allelopathic activity, while chlorogenic acid and orientin had the lowest on the basis of the rank values. Benzoic acid was found in the highest concentration in the methanol leaf extract, while this compound was not identified in the water leaf extract. On the other hand, the predominant compound was orientin for stem extracts. These re-sults suggest that these compounds may be involved in the allelopathy activity of Tinospora tuberculata de-pending on their number, concentration, combination and inhibitory activity. Tinospora tuberculata could be a potential source of natural inhibitor compounds employable for eco-friendly agriculture
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