1,721,027 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
Dermination of four thiophenethylamine desigrer drugs (2C-T-series) in human plasma by Capillary Electrophoresis with mass spectrometry detection
No full textIn recent years, the frequent appearance of phenethylamine designer drugs on the illicit drug market has been a matter of concern for all
authorities involved. New phenethylamine drugs are being introduced because these compounds are not covered by existing legislation. Therefore,
the new drugs cannot be considered illicit drugs until their names are officially recognized. This paper describes a method to screen for and
quantify four 2,5-methylenedioxy-derivatives of 4-thio-phenethylamine (2C-T-series) in human plasma, using capillary electrophoresis coupled
with electrospray ionisation-mass spectrometry (CE-ESI-MS). Prior to CE-MS analysis, a simple liquid extraction was used for sample cleanup.
The method was validated according to international guidelines
Estrazione e determinazione di deltametrina nel suolo e di carbaryl e benomyl nella quercia da sughero
No full textA rapid method for determination of four thioamphetamine designer drugs (aleph-4, aleph-8, aleph-13, aleph-17) in human urine
No full textAn analytical procedure for the simultaneous determination in human urine of four
thioamphetamine designer drugs (ALEPH series) is reported. The quantitative analysis was
performed by capillary electrophoresis with diode array detector (CE-DAD), using 2,5-dimethoxy-4-
methylthioamphetamine-D3 (ALEPH-D3) as internal standard. In order to minimize interferences
with matrix components and to preconcentrate target analytes, solid phase extraction was introduced
in the method as a clean-up step. The method was validated according to international
guidelines. Data for accuracy and precision were within required limits. Calibration curves were
generated ranging from 1 to 500 lgmL1 and correlation coefficients always exceeded 0.998.
The method was demonstrated to be specific, simple, and reliable for the analysis of these derivatives
in urine samples.An analytical procedure for the simultaneous determination in human urine of four
thioamphetamine designer drugs (ALEPH series) is reported. The quantitative analysis was
performed by capillary electrophoresis with diode array detector (CE-DAD), using 2,5-dimethoxy-4-
methylthioamphetamine-D3 (ALEPH-D3) as internal standard. In order to minimize interferences
with matrix components and to preconcentrate target analytes, solid phase extraction was introduced
in the method as a clean-up step. The method was validated according to international
guidelines. Data for accuracy and precision were within required limits. Calibration curves were
generated ranging from 1 to 500 lgmL1 and correlation coefficients always exceeded 0.998.
The method was demonstrated to be specific, simple, and reliable for the analysis of these derivatives
in urine samples
Determination of p-methoxyamphetamine by capillary electrophoresis with diode array detection from urine and plasma samples
No full textMulti-Residue Analysis of eight Thioamphetamine Designer Drugs in Human Urine by Liquid Chromatography/Tandem Mass Spectrometry
No full textAn analytical procedure for the simultaneous determination in human urine of several thioamphetamine
designer drugs (2C-T and ALEPH series) is reported. The quantitative analysis was performed
by liquid chromatography/tandem mass spectrometry and has been fully validated. The mass
spectrometer was operated in positive-ion, selected reaction monitoring (SRM) mode. In order to
minimize interferences with matrix components and to preconcentrate target analytes, solid-phase
extraction was introduced in the method as a clean-up step. The entire method was validated for
selectivity, linearity, precision and accuracy. The method turned out to be specific, sensitive, and
reliable for the analysis of amphetamine derivatives in urine samples. The calibration curves were
linear over the concentration range of 1 to 100 ngmL1 for all drugs with correlation coefficients that
exceeded 0.996. The lower limits of detection (LODs) and quantification (LOQs) ranged from 1.2 to
4.9 ngmL1 and from 3.2 to 9.6 ngmL1, respectively
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