1,720,977 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
Aluminum determination in biological fluids and dialysis concentrates via chelation with 8-hydroxyquinoline and solvent extraction/fluorimetry
No full textWe describe a simple, rapid, and sensitive fluorescence method for measurement of aluminum (Al) in human biological fluids, in dialysis solutions and in tap water, which uses 8-hydroxyquinoline for ion chelation. The fluorescence intensity Of the toluene-extracted metal chelate (excitation wavelength, 380 nm; emission wavelength, 504 nm) remains unchanged for over 48 h at room temperature. Fluorescence intensity is a linear function of the concentration of Al in the 2-1000 mu g/L range with detection limits of 0.7-2 mu g/L. A large excess of other ions normally found in biological fluids does not interfere in Al determination. The method developed was Successfully used in assaying Al in serum and urine of reference Subjects, in serum samples from patients undergoing long-term dialysis, and in dialysis solutions. Al concentrations, measured by this fluorimetric procedure, were compared with those obtained by Zeeman graphite-furnace atomic absorption spectrometry. A correlation coefficient of 0.98 was obtained. The proposed method could be used for routine analysis in clinical laboratories for accurate determination of aluminum in aqueous or biological fluids
Urinary excretion of 1-hydroxypyrene as a biomarker of exposure to polycyclic aromatic hydrocarbons from different sources
No full text1-Hydroxypyrene (1-OHP) urinary excretion has been studied in subjects
exposed to polycyclic aromatic hydrocarbons (PAH) from different sources
(urban air pollution, cigarette smoking, food contamination or
occupational exposure). In Study A, statistically significant
differences among subjects categorized according to daily cigarette
consumption were observed: 1-OHP median excretion of heavy smokers (more
than 20 cigarettes per day; 1-OHP = 371 ng l(-1); n =6) was
significantly increased over that of non-smokers (1-OHP = 160 ng l(-1);
n = 79), light smokers (less than 10 cigarettes per day, 1-OHP = 157 ng
l(-1); n = 7) and also medium smokers (10-20 cigarettes per day, 1-OHP =
154 ng l(-1); n = 13) (p < 0. 04). In smokers, 1-OHP excretion (y, ng
l(-1)) increased with the intensity of cigarette consumption and was
associated with self-reported number of cigarettes smoked daily (x, n)
(y = 20 + 16.6x; r = 0.58, n = 22, p < 0.01), urinary thiocyanate (x, mu
ol l(-1)) (y = 55 + 2.6x; r = 0.57, n = 20, p < 0.01) and cotinine (x,
mu g l(-1)) (y = 89 + 0.23x; r = 0.62, n = 17, p < 0.01). In Study B the
influence of smoked food consumption on 1-OHP excretion was evaluated:
1-OHP excretion began to increase as soon as 3 h after a PAH-rich meal
and peak values were reached between 6 and 9 h after lunch. Maximum
excretion mean values were respectively 525 ng l(-1) for non-smokers (n
= 8) and 650 ng l(-1) for smokers (n = 4). 1-OHP concentrations in
next-morning samples were back to pre-lunch levels both for non-smokers
and smokers. In Study C non-smoker workers (n = 28) occupationally
exposed to PAH in a steel plant were investigated. At values of airborne
pyrene ranging between 6 and 30 mu g m(-3), excretion values of 1-OHP up
to 80 000 ng l(-1) were observed. The use of urinary 1-OHP as a
screening test to discriminate between smokers and non-smokers in the
presence of uncorrected dietary influence has been calculated according
to a cut-off value of 461 ng l(-1) (reference group upper limit): the
1-OHP positive predictive value is 57 \%, its predictive negative value
is 77 \%, sensitivity is 15\% and specificity is 96 \%. In conclusion,
1-OHP appears to be a valuable biomarker of pyrene exposure. It will be
nevertheless more accurate in assessing human PAH exposure from multiple
sources if the influence of different kinetics for inhaled (particulate
or gaseous) or ingested PAH are considered and if the role of oxidative
polymorphism is adequately elucidated. The possibility of using 1-OHP to
estimate the total burden of PAH from different sources or of screening
groups with different PAH exposure appears to be a possible approach.
However, the use of 1-OHP to evaluate the associated risk of cancer is
still a premature target
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
[Biological monitoring of environmental benzene exposure in traffic wardens]
No full textVehicle exhausts are a well known source of aromatic hydrocarbon pollution in urban environments. The paper reports the results of environmental and biological monitoring of benzene exposure in traffic wardens carried out over a 5-hour workshift. Subjects (n = 131) were grouped according to smoking habits and job task as follows: group (A) 52 nonsmoking office workers, (B) 43 nonsmoking outdoor workers, subdivided into (B1) 36 working on foot and (B2) 7 cyclists; (C) 20 smokers office workers, (D) 16 smokers outdoor workers, subdivided into (D1) 11 working on foot and (D1) 5 cyclists. The median indoor environmental benzene concentration (26 micrograms/m3, n = 50) was significantly lower than the outdoor concentration (45 micrograms/m3, n = 43) (p < 0.01); median exposure value of cyclists was 78 micrograms/m3 (n = 12). For biological monitoring, urinary excretion of trans,transmuconic acid was determined in spot samples collected at 7:30 h (MAit) and 12:30 h (MAft). The MAftA median value (63 micrograms/l, range 2-242 micrograms/l) was not statistically different from MAftB (74 micrograms/l, range 15-216 micrograms/l), while the MAftB2 value of 96 micrograms/l was higher than both MAftB1 (71 micrograms/l) and MAftA. In group (B) there was a relationship between airborne benzene levels and MAftB excretion (y = 17.2 + 1.1x, r = 0.62, n = 35, p < 0.01). The influence of smoking on urinary MA excretion was studied by comparing the results obtained in all nonsmokers (AB) with smokers (CD). MAftCD (192 micrograms/l) was significantly higher than MAftAB (69 micrograms/l) (p < 0.01). In smokers, statistically significant relationships were observed between urinary excretion of MAft (y, microgram/l) and cotinine (x, microgram/l) (y = 83 + 0.08x, r = 0.73, n = 23, p < 0.01), and smoking (x, number cigarettes/day) (y = 87.4 + 4.4x, r = 0.53, n = 29, p < 0.01). Comparison between MAft and MAit median excretion values, calculated for each of the 6 exposure groups, showed that MAft was always higher than the corresponding MAit value. A rough estimate of the total dose of benzene ("index of exposure", EI) inhaled by each subject during the 5-hour working shift as a consequence of air pollution and smoking was also made. Considering the entire group of subjects, a significant association was observed between EI and MAft values (y = 43.4 + 0.39x, r = 0.65, n = 104, p < 0.01). Individual values of MA it were correlated with MAft according to the equation y = 43.6 + 0.82x (r = 0.62, n = 105; p < 0.01) and were also positively associated with EI values (y = 42.3 + 0.20x; r = 0.55; n = 74; p < 0.01). In conclusion, the results suggest that the measurement of urinary MA excretion is a poor indicator for assessing environmental benzene exposure at levels below 100 micrograms/m3, such as those seen in this study; MA can however be reliably used as a biomarker for higher exposures such as those, for example, due to smoking
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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