1,721,030 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
Amazonian plants from ethnomedicine to biotechnology through pharmaceutical biology approaches: a PhD experience in connecting forest with laboratory
No full textThe South american Natives, Shuar and Achuar people and their ethnomedical culture constitute the
background subject of the Phd research, performed both in Ecuador (Salesian Politechnic University,
Quito), and in Italy (Pharmaceutical biology labs, University of Ferrara). Based on ethnomedical
responses, Piper aduncum, Maytenus macrocarpa, Schinus molle, Tecoma stans and Eugenia hallii were
chosen as amazonian plant species subject of the research.
AIMS
The research has been focused on:
− checking the presence of endophytic fungi in plants;
− isolating and subculturing pure endophytic strains;
− checking the biotransformation capacity of the isolated endophytes on pure compounds; the most
performing endophytes were also tested on phytocomplexes and pure chemicals obtained by the
plant from which the fungi were isolated;
− phytochemical characterization and bioactivity assays of plant extracts: P. aduncum.
−
METHODS
Biotransformations. Fresh aerial plant parts were properly washed in sanitizing solutions and in vitro
cultured using adequate solid media to isolate endophytes. (+/-)-cis-bicyclo[3.2.0]hept-2-en-6-one,
acetophenone, 1-indanone, 2-furyl methyl ketone, 2-methylcyclopentanone, 2-methylcyclohexanone, 2-
methoxycyclohexanone were chosen as substrate model for biotransformations. The cultures were
sampled after 1, 3, 7, 10 days of culturing, and ethyl acetate extracted to verify by GC-MS the presence of
possible biotransformation products. Biotransformations were also checked on P. aduncum whole
essential oil and on dillapiol, cis-ocimene, piperitone, (-)-terpinen-4-ol as most abundant chemicals.
Chemical fingerprinting of P. aduncum essential oil. Steam distillation was adopted to obtain the essential
oil, then characterized by GC-MS, NMR analyses.
In vitro bioassays of P. aduncum essential oil. Antimicrobial activities were checked in vitro using proper
agarized media to reach MIC. Antioxidant capacities were checked through DPPH test, ABTS and
photochemiluminescence assays. Born's turbidimetric method and Writhing test were respectively
adopted to check platelet-aggregation and anti-nociceptive properties. Mutagenic, antimutagenic
properties and toxicity were assayed using classical and modified Ames test.
MAIN RESULTS
364 fungal strains were in vitro isolated. Among all, 5 strains performed biotransformations on
acetophenone to (S)-1-phenylethanol, with important yields (78-97%) and enantiomeric excess (78-
100%). Three strains gave also phenols probably by enzymatic reactions (Baeyer-Villiger oxidations). 15
fungal strains gave the lactones (-)-(1S,5R)-2-oxabicyclo[3.3.0]oct-6-en-3-one and (-)-(1R,5S)-3-
oxabicyclo[3.3.0]oct-6-en-2-one from (+/-)-cis-bicyclo[3.2.0]hept-2-en-6-one, probably as result of
monooxygenase activation. Phytochemical characterization of P. aduncum essential oil has evidenced
dillapiol as the most abundant terpene, followed by cis-ocimene, piperitone and terpinen-4-ol. Only cisocimene
and piperitone gave several biotransformation products through dehydrogenation and
hydroxylation reactions. The essential oil has evidenced non-mutagenic properties and interesting
antifungal and antioxidant activities.
CONCLUSIONS
Several endophytic fungal strains from Amazonian plants were isolated and checked for
biotransformations on pure chemicals and on P. aduncum essential oil. Data obtained will be useful for
possible following patents about micro-organisms able to transform pharmaceutically interesting
chemicals. Taxonomical characterization of the most performing fungal strains is still in progress. P.
aduncum essential oil can be considered genotoxically safe and provides interesting antifungal and
antioxidant properties, supporting its ethnomedical use as cicatrising and disinfectant crude drug and
suggesting an extension of its employ as preservative ingredient
Characterization of polyphenols in Vaccinium berries and evaluation of their chemopreventive properties
No full textThis study was aimed at the complete metabolite profiling of polyphenols in Vaccinium floribundum Kunth berries from Ecuador by means of HPLC-UV/DAD, HPLC-ESI-MS and MS2, using an ion trap mass analyzer. As a comparison, Vaccinium myrtillus L. berries from the Italian Northern Apennine were analyzed in parallel. A sequential selective extraction procedure was developed to maximize the yields of the secondary metabolites from the berries, using ethyl acetate for flavonoids and phenolic acids, followed by acidified methanol for anthocyanins. The results of the HPLC analyses indicated several representative differences in both the quali- and quantitative composition of flavonoids and anthocyanins in the berry extracts obtained from V. floribundum and V. myrtillus, which showed typical fingerprints of their phenolic secondary metabolites. Thanks to its unique polyphenol composition, V. floribundum can be easily differentiated from common bilberries using the proposed techniques.
The chemopreventive activity of these berries and their fractions was evaluated by the determination of their antioxidant activity using a panel of in vitro tests (DPPH, ABTS) and their antimutagenic properties against dietary and environmental, direct and indirect, mutagens. The results of these biological assays were correlated with the chemical composition of the two investigated Vaccinium species, to establish the potential application of V. floribundum as a source of phytochemicals in the nutraceutical and functional food ambit
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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