1,720,992 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
White wine dealcoholization by osmotic distillation: An experimental study and impact on key quality parameters
Full text linkThis study aimed at investigating the impact of the osmotic distillation (OD) process parameters, including feed and stripping flow rates, on the removal of ethanol from white wine for the production of dealcoholized wine (0.5% v/v ethanol). The research evaluated the dealcoholization kinetics and ethanol mass transfer behavior using mathematical modeling, alongside investigating the impact of different ethanol levels on physico-chemical parameters, color profile and volatile composition of the wine. The results showed that without renewing the stripping solution, ethanol reduction stabilizes after several dealcoholization cycles due to an equilibrium between ethanol content in the feed and stripping side. However, renewing the stripping solution increased ethanol removal rates, facilitating the production of dealcoholized wine. Additionally, variations in feed and stripping flow rates without renewing the stripping solution, in the range of investigated values, did not significantly impact the ethanol removal rate. The total weight loss during the production of dealcoholized wine (0.5% v/v) was 20.7%. Partial dealcoholization (up to 4.6–5.0% v/v) showed minor changes in physico-chemical parameters of wine, while full dealcoholization at 0.5% v/v resulted in changes in acidity, pH, several non-volatile compounds and color of wine. The reduction in total volatile compounds showed a positive correlation (r = 0.93) with ethanol removal, in particular for the loss of esters (reduced by 89%), alcohols (78%), acids (86%), carbonyl compounds (96%) and volatile phenols (88%)
Microwave-assisted extraction and membrane-based separation of biophenols from red wine lees
No full textWinemaking generates huge quantities of waste streams with high added value which can be recycled for the production of innovative products in different market areas. In particular, wine lees contain high concentration of bioactive molecules which can be exploited to obtain extracts or semifinished products of interest for food, nutraceutical and pharmaceutical applications. In agreement with a biorefinery approach applied to winemaking, this work aimed at evaluating the potential of an integrated process, based on a combination of microwave-assisted extraction and membrane-based operations, for the recovery of phenolic compounds from red wine lees before using biomass for energy purposes. Specifically, the hydro-alcoholic extract was clarified by microfiltration (MF) and then processed with three different polymeric membranes: an ultrafiltration (UF) membrane with a molecular weight cut-off (MWCO) of 1000 Da (Etna 01PP) and two nanofiltration (NF) membranes with MWCO of 150–300 Da (NFT50 and Desal DK). The performance of selected membranes was measured in terms of permeate flux, fouling index and retention of phenolic compounds and sugars. Experimental results indicated that all these parameters are mainly affected by membrane material and pore size. All tested membranes did not show a preferential rejection of phenolic compounds over sugars. Among the selected membranes the NFT50 presented the highest retention towards phenolic compounds allowing to maximize the recovery of these compounds in the retentate fraction
Enzyme-mediated extraction of limonene, linalool and linalyl acetate from bergamot peel oil by pervaporation
Full text linkBergamot peel oil is highly attractive for food and pharmaceutical industries due to its content of valuable essential oil, which is enriched with high-added valuable compounds, such as limonene, linalool and linalyl acetate. Nevertheless, there are some limitations for the separation of such compounds. In this framework, pervaporation (PV) technology was proposed as a tool for the separation of limonene, linalool, and linalyl acetate from bergamot oil by using two different commercial organophilic membranes (PDMS-1070 and POMSPEI). The use of an enzymatic pre-treatment was also investigated in order to enhance the performance of selected membranes. All PV experiments were carried out at different temperatures (ranging from 25-40 °C) in order to analyze the temperature dependence by the Arrhenius relationship. Experimental data indicated that both investigated membranes did not present significant differences in terms of enrichment factor, independently from the enzymatic pre-treatment (at 25 °C). However, the enrichment factors increased significantly at 40°C when enzymes were applied. The experimental results clearly indicate that PV is a viable approach for the recovery of such aroma solutes from bergamot peel oils as it yields good separations under mild operating conditions. The efficiency of the pervaporative process is indeed enhanced if assisted by an enzymatic treatment
Evaluating membrane behavior to ethanol-water mixtures and wine: a comparative investigation
Full text linkIn this study the performance of three nanofiltration membranes (TS 40, NF99, HL) and one reverse osmosis membrane (RO-SE) while filtering ethanol-water mixtures (0–10.5% v/v) and a white wine (10.5% v/v) was evaluated. The experiments were conducted using water, ethanol-water mixtures, and white wine at varying pressure (0–20 bar, 21 ± 1 °C) to explore the impact of pressure on permeate flux and permeability. Further tests were performed with white wine and ethanol-water mixture (10.5% v/v) at pressure 20 bar and 21 ± 1 °C up to volume reduction factor of 4 to evaluate performance (based on permeate flux, permeability, fouling index, ethanol rejection and retention of selected compounds) of different membrane. Among the investigated membranes the HL membrane exhibited the highest permeate flux consistently across varying operational pressures, showcasing superior permeability. HL and NF99 membranes showed greater effectiveness in reducing the alcohol content in wine, with ethanol rejection rates of 5.14% and 5.46%, respectively. Conversely, RO-SE (10.64%) and TS 40 (18.30%) exhibited the highest ethanol rejection rate. The fouling index for all the membranes ranged between 22.5 and 43.5%. In addition to this NF and HL also showed highest rejection towards reducing sugars (>90%), glucose (>80%), fructose (>88%), citric acid (>88%) and tartaric acid (>89%) in dealcoholized wine. Overall, HL and NF99 membranes appear to be the most effective options for wine dealcoholization
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
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