1,720,972 research outputs found
A computational investigation on singlet and triplet exciton couplings in acene molecular crystals
No full textQuantum chemical calculations (DFT, TDDFT and ZINDO/S) of singlet and triplet exciton couplings are presented and discussed for some acene derivatives (such as anthracene, tetracene, 9,10-di(phenyl) anthracene and 9,10-bis(phenylethynyl) anthracene). An accurate excited state single molecule characterization has been carried out followed by an analysis of the inter-molecular excitonic interactions, taking place in the crystalline phase. These have been correlated to exciton coupling terms obtaining guidelines for the choice of molecular materials with large exciton couplings. Such organic systems are likely to show multiexciton processes such as singlet fission (SF) and triplet-triplet annihilation (TTA) which are useful in energy conversion phenomena to be exploited in photonic and optoelectronic devices
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
Effectiveness of installing an anti-bacterial filter at water taps to prevent legionella infections
No full textLegionella pneumophila is frequently found in hospital hot water mains. To prevent Legionella infection, numerous methods have been applied to eradicate Legionella pneumophila from the hospital water circuit, hyperchlorinization through the use of sodium hypochlorite, calcium hypochlorite and chlorine dioxide, overheating and flushing, copper and silver ionization, UV radiation and ozonization. Nevertheless, the above methods are not always effective, at times achieving only temporarily solving the problem. Installation of anti-bacterial filters at the points where water is used (taps and shower heads) offers some indisputable advantages: installation can be limited to the high risk areas; installation and maintenance are simple and inexpensive. Nevertheless, it is worth noting that most filters last a maximum of 15 days and this constitutes a significant drawback to their use. Recently, however, a filter to protect showerheads from passage of Legionella has been created with a porosity of 0.2 m (Pall – Aquasafe Shower Head Filter, AQL3). The filter membrane resists a maximum recommended water temperature of 60°C and has an operating lifespan of one month. The purpose of the present research was to evaluate whether installation of this filter in 8 showers found in different departments located in different areas of the S. Orsola Malpighi Hospital in Bologna, Italy could prevent the presence of this microorganism in the water over the period of one month. At the time of installation all showers showed the presence of Legionella contamination (102 – 104 cfu/l). Moreover, it is worth noting that, for the entire test period, no other water sanitation system was used. The samples were taken before installation of the filter and once a week thereafter for 4 weeks. After a month the filters were changed and additional samples were taken after 15 and 30 days. All colonies fell under serum group 3. After installation of the filter, no Legionella colonies were found in the water downstream of the filter nor was it possible to detect Legionella 15 and 30 days after the filters were replaced. For the quantities sampled and the dilutions used, the lower limit for Legionella detection was 50 cfu/l. The results lead one to conclude that, prior to installation of the filter, the number of Legionella bacteria present in the hot water mains was at limit levels. As in most countries, Italian Guidelines permit possible water contamination containing between 102-104 cfu/l of Legionella. Therefore it is clear that use of the filters made it possible to eliminate the potential risk of infection
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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