1,721,096 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
Bioactive compounds in lentils and nutraceutical effects
No full textLentils are an endemic crop of central Italy in particular of Umbro-Marchean Apennines and some of these are recognized by the European Union with the acronym PGI, Protected Geographical Indication. Among pulses, lentils have high nutritional value and they are an important sources of bioactive compounds: besides nutrients such as PUFA (regulation of cognitive function, cardiovascular diseases prevention) there are important nutraceutical compounds such as soyasaponins (hypocholesterolemic, antiepatotoxic and anticarcinogenic activity) and isoflavones (osteoporosis prevention, ameloriation postmenopausal symptoms, tumor initiation prevention). In our labs, several methods to determine the above compounds have been validated and applied to lentils and other legumes using HPLC-MS, UHPLC-MS/MS, GC-FID systems. Furthermore, some in vivo and in vitro biological studies have been performed, such as anti-hypercholesterolemic effect on a rat model with diet induced hypercholesterolemia. Additionally, toxic effect of soyasaponins and lentil extracts have been studied in vitro on caco-2 cells.
Results showed that soyasaponins I and βg are present in lentils in concentrations ranging from 541 to 1457 mg kg−1. The isoflavone content in lentils ranged from 0.41 to 58.61 μg kg-1. Unsaturated fatty acids are predominant in lentils with respect to saturated fatty acids. Soyasaponin I and lentil extracts no cytotoxic effect produced in Caco-2 cells at the tested concentrations. Lentils are an important source of bioactive compounds and lentils extracts may have a nutraceutical effect.
References
1Vila-Donat, P.; Caprioli, G.; Conti, P.; Maggi, F.; Ricciutelli, M.; Torregiani E.; Vittori, S.; Sagratini, G., Food Anal. Meth., 2013, DOI 10.1007/s12161-013-9708-3. 2Vila-Donat, P., Caprioli, G., Maggi, F., Ricciutelli, M., Torregiani, E., Vittori, S., Sagratini, G., Food Chem., submitted. 3Folch, J., Lees, M., Sloane Stanley, G. H. (1956). J. Biol. Chem., 1956, 226, 497-509
Effect of the ultrasound-assisted extraction parameters on the determination of ergosterol and vitamin D2 in Agaricus bisporus, A. bisporus Portobello, and Pleurotus ostreatus mushrooms
No full textErgosterol is an important secondary metabolite precursor of vitamin D2 in mushrooms and is responsible for
various health-promoting effects. The increasing interest in searching and analyzing foods rich in provitamin and
vitamin D requires the optimization of a fast and effective extraction method. The comprehensive optimization of
the parameters influencing ultrasound-assisted extraction (U.A.E) was performed to determine the best U.A.E
conditions for ergosterol and vitamin D in mushrooms. The highest extraction yields were obtained with ethanol
as solvent, 20 mg/mL as the solid-solvent ratio (SSR), at a frequency of 40 kHz, and a power of 240 W, for 30 min
at 40 ◦C. For conjugated ergosterol, U.A.E in basic conditions (pH 11 using an ethanolic solution of KOH) at
60 ◦C for 30 min was ideal. Moreover, saponification after U.A.E did not provide any improvement on the
extraction yield. The developed U.A.E. methods were applied on three mushroom species obtaining high levels of
total ergosterol for Agaricus bisporus (6.8 ± 0.1 mg/g dw), A. bisporus Portobello (7.3 ± 0.2 mg/g dw), and
Pleurotus ostreatus (4.9 ± 0.1 mg/g dw). Moreover, good levels of vitamin D2 (13.9–19.2 mg/100 g dw) in
mushrooms were obtained after ultraviolet-C (UV-C) irradiation
Semi-automated liquid chromatography-mass spectrometry (LC-MS/MS) method for basic pesticides in wastewater effluent
No full textEffluent from wastewater treatment plants have been identified as an important source of micro-organic contaminants in the environment. An online highperformance liquid chromatography–heated electrospray ionization tandem mass spectrometric method was developed and validated for the determination of basic pesticides in effluent wastewaters. Most available methods for pesticide analysis of wastewater samples are time-consuming, require complex clean-up steps and are difficult to automate. The method developed used a simple solid-phase extraction clean-up for salt and lipid reduction. On-line sample pre-concentration was performed using a reversed phase (C18) column, and analytes were separated by back-flushing onto an analytical column (C8) with detection using QqQ MS. An option to increase MS resolution was exploited to minimize interference from endogenous compounds in the matrix. A better than unit mass resolution was used (Q1 full width half maximum (FWHM)=0.2 Da and Q3 FWHM=0.7 Da), which was as
rugged as a unit resolution method, and improved signal/noise and better detection limits were achieved for the targeted basic pesticides. This method was applied to the determination of 11 pesticides, including methoxytriazine, chlorotriazines, chloroacetanilides, phenylurea and carbamate pesticides. The percentage recovery values for these pesticides using the online trapping column were within the range, 73–95%, with relative standard deviation (RSD) values <8.9%. The highest concentrations of these pesticides in wastewater effluents in County Cork, Ireland, were simazine (0.51 μg/L), prometon (0.14 μg/L), diuron (0.21 μg/L) and atrazine (0.19 μg/L)
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
Assessment of lipid oxidation in fish and fish products processed by cold plasma technologies
Full text linkPlasmas generated at or near ambient temperature are emerging as mild, selective and environmentally friendly technologies for extending the shelf-life of perishable fish and fish products. However, the high degree of unsaturation makes fish lipids highly susceptible to the reactive oxygen and nitrogen species (RONS) of plasmas, which can trigger the onset and/or progression of lipid oxidation, leading to the formation of off-flavours, the loss of nutritionally valuable components (polyunsaturated fatty acids, proteins, vitamins) and the formation of risky or toxic substances. Despite numerous experiments on the decontamination effects of cold plasma on fish and fish products, the evaluation of lipid oxidation has been limited to a few parameters. Most studies have focused on measuring global indices of primary and secondary oxidation products (peroxide value and thiobarbituric acid reactive substances, respectively) and some researchers have analysed total fatty acid composition as an indirect measure of the degree of oxidation. However, more advanced analytical methods for the direct quantification of volatile and non-volatile chemical species derived from the oxidation of fatty acids and sterols have been performed only to a very limited extent. The results on the effects of cold plasma on lipid oxidation in fish and fish products are contradictory. Although several studies show a pro-oxidant effect of RONS, others report no significant effects on lipid oxidation and even a lower rate of lipid oxidation during storage of fish products
Quality traits of raw and cooked cupped oysters
Full text linkProximate composition and fatty acid profile of raw cupped oysters (RA) were compared to conspecific submitted to two different cooking preparations (SA: cooking using extra virgin olive oil in a pan; GR: “gratin”). Moister content was significantly higher in RA (81.7%) with respect to SA (81.1%) and GR (81%). Protein rate significantly decreased from RA (8.8%) to SA (8.3%) and GR (8.4%). Lipids significantly increased in the two cooked GR (2.8%) and SA (2.7%) with respect to RA (2%). Ashes ranged from GR (1.98%) to RA (2%). In the two cooking methods, 18:0 was significantly higher (GR 6.99% and SA 6.15%) than in the raw oysters (RA 4.87%). C18:1 was largely doubled in GR (14.43%) and SA (13.77%) with respect to RA (6.81%). Among n-3 PUFA, 22:6 showed the highest percentage in all the three samples with a significant decrease passing from RA (21.39%) to SA (18.45%) and GR (17.95%). 20:5n-3 had the highest content in RA (17.53%) and significantly decreases in SA (14.09%) and GR (14.54%). Considering the trend of n-3 PUFA and n-6 PUFA, the n-3/n-6 ratio significantly decreased from RA (5.33) to SA (3.58) and GR (3.29). Although proximate composition and fatty acid profile changed after the cooking process, as consequence of the heat treatment and extra virgin olive oil added to the plates, the culinary preparations did not negatively compromise the quality traits of the cooked and gratin oysters
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