1,720,973 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
Studio quali-quantitativo di Arbutus unedo L.
No full textNell‘ambito della ricerca di specie della flora della Sardegna quali fonte di agenti antiinfiammatori topici per il trattamento di patologie flogistico-infettive del basso tratto genitale femminile, è stata selezionata la specie Arbutus unedo. Arbutus unedo L. (Ericaceae), comunemente noto come corbezzolo, è una specie arbustiva o arborea diffusa nel bacino del Mediterraneo. Il nome "arbutus" deriverebbe dalla radice celtica "ar" = aspro e "butus" = cespuglio, con probabile allusione al sapore di foglie e frutti. Le foglie di questa pianta sono utilizzate nella medicina tradizionale dell‘area mediterranea, soprattutto per le proprietà diuretiche, antisettiche delle vie urinarie, antidiarroiche, ipotensive ed antidiabetiche (1,2). Inoltre, studi sperimentali nel topo hanno evidenziato proprietà antiflogistiche per alcuni estratti, dopo somministrazione orale (2). Indagini fitochimiche hanno invece rivelato la presenza di composti fenolici (3) caratterizzati da interessanti attività biologiche. Lo scopo del presente lavoro è stato lo studio e la caratterizzazione del profilo dei componenti polifenolici di Arbutus unedo. Lo studio fitochimico di A. unedo è stato effettuato sulle parti aeree che, dopo un preliminare sgrassamento con n-esano, sono state sottoposte ad estrazione con Etanolo. Lo studio dell‘estratto etanolico, attraverso varie tecniche cromatografiche quali Sephadex LH-20, cromatografia di adsorbimento e RP-HPLC, ha portato all‘isolamento di alcuni metaboli secondari: arbutin, β-D-glucogallina, gallic acid 4-O-β-d-glucopyranoside, 3-O-galloylquinic acid, 5-O-galloylquinic acid gallic. I composti isolati sono stati identificati mediante studi spettroscopici UV, 1H-NMR, 13C-NMR e mediante spettrometria di massa ESI-MS. Successivamente sono state avviate analisi HPLC-DAD-MS con lo scopo di quantizzare i componenti fenolici presenti in questa specie (4,5)
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
Evaluation of Biological activity in Algerian and Italian cultivars of Olea europeae L. extracts
No full textOlea europaea L. is a typical fruit-tree widely cultivated in the Mediterranean area, belonging to Oleaceae family. The fruits and the oils are mainly studied for their alimentary use as important components in the daily diet of a large part of the world’s population. The growing interest in olives is due to secondary metabolites content and their role in human health. It is well-known that the decreased incidence of cardiovascular disease in the Mediterranean area has been partly attributed to the consumption of olive products (1). In this work, the identification and quantification of phenolic compounds in olive fruit extracts of two Algerian (Chamlal and Sigoise) and five Italians cultivars collected in Basilicata (Leccino, Ogliarola del Bradano, Maiatica, Frantoiana and Coratina) was carried out. Antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power and ß-carotene bleaching assays was also performed and Relative antioxidant capacity index was calculated (2).
Fourteen compounds, indentified by HPLC-DAD HRMS analysis, can be divided into four classes: phenolic acids, flavonoids, phenolic alcohols and secoiridoids.
There were no significant qualitative differences among samples, but it is possible to note important quantitative differences. Chemlal, between the Algerian cultivars, and Coratina, among Italians, demonstrated the highest content of polyphenols related to a higher radical scavenging activity and reducing power. The major contributors of their antioxidant activity were hydrotyrosol, and verbascoside. Results of our work revealed that there are significant differences among health promoting values of different Olea europaea cultivar due to the amount of bioactive compounds
Phenolic compounds in olives and olive oil from Algerian and Italian Olea europaea cultivars and their antioxidant activity
No full textOlive fruits (OF) and virgin olive oil (VOO) have nutritional and sensory characteristics that make it unique and a basic component of the Mediterranean diet.1 The chemical composition of phenolic of OF and VOO is mainly affected by the variety, location, and environmental conditions.2 Phenolic compounds of OF and VOO affect olive and oil shelf lifes since they retard oxidation and the sensorial properties: color, astringency, bitterness, and flavour.2,3 and possess protective effects on human health, including cancer and cardiovascular diseases. In the present study, the identification and quantitation of the most representative phenolic compounds present in OF and VOO of two Algerian (chamlal and sigoise) and some Italian cultivars (leccino cat, ogliarola bradano, maiatica pandolfo, frantoiana pandolfo, leccino pandolfo, frantoiana cat, coratina) using HPLC-DAD based method is reported. HPLC-DAD HRMS was also used to confirm results obtained. Quantitative or semi-quantitative information on OF and VOO phenols is of great interest to find the compounds responsible of the olive oil benefits and to distinguish VOOs with different geographical origin.2,3 Analyzed olive extracts and oils demonstrated significative differences (p < 0.05) in secondary metabolite identified, expecially concerning phenolic acids. The antioxidant activity was also measured using: 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power and β-carotene bleaching assays, 4,5 and relative antioxidant capacity index.5 According to all tests, the highest hydroxytyrosol amount and antioxidant capacity were observed for the Italian cultivars coratina and ogliarola, and the Algerian cultivar chamlal
Phenolic compounds from Clinopodium tomentosum (Kunth) Govaerts (Lamiaceae)
No full textPhytochemical investigation of the leaf extracts of Clinopodium tomentosum (Kunth) Govaerts (Lamiaceae) allowed the isolation of one new compound, named 2-O-benzoyl-3-O-cinnamoyl tartaric acid, along with twelve known compounds, dihydrodehydroconiferyl alcohol 9'-O-β-Dglucopyranoside, blumenol c glucoside, syringaresinol 4'-O-β-D-glucopyranoside, hesperetin, pinocembrin 7-O-rutinoside, clinopodic acid E, caffeic acid, p-coumaric acid, caffeic acid methyl ester, caffeic acid ethyl ester, rosmarinic acid, and rosmarinic acid methyl ester. Their structural characterization was obtained on the basis of extensive spectroscopic analyses, including mono- and bidimensional nuclear magnetic resonance (1D and 2D NMR) experiments and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS)
New phenolic glycosides from Securinega virosa and their antioxidant activity.
No full textOne new flavonoid glycoside, 3-O-kaempferol 4-O-(galloyl)-beta-D-glucoside, one new bergenin derivative, 11-O-caffeoylbergenin, along with other known flavonoids and phenolic derivatives, were isolated from the leaves of Securinega virosa. Their structures were established on the basis of detailed spectral analysis. In vitro biological analysis of the isolated compounds showed that they were able to quench DPPH radicals and had a direct scavenging activity on superoxide anion. Kaempferol 3-O-(4-galloyl)-beta-D-glucopyranoside (1), 11-O-caffeoylbergenin (2), and glucogallin (6) exhibited the highest antioxidant capacity, being also able to modulate hydroxyl radical fori-nation more efficiently than the other compounds, acting as direct hydroxyl radical scavengers and chelating iron
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