1,720,970 research outputs found
Preliminary Investigations To Identify Seven Neonicotinoid Insecticides in Honeybee Samples
Full text linkNeonicotinoids (NEOs) are widely used pesticides aimed at controlling harmful insects but can pose significant risks to human health, including potential links to cancer, infertility, and congenital disabilities. Consequently, monitoring NEO residues in food is critical to safeguard public health and support ecological stability. This study presents a newly developed and validated method to measure residues of clothianidin, acetamiprid, imidacloprid, dinotefuran, nitenpyram, thiamethoxam, and thiacloprid in honeybee samples. The method uses a STRATA XPRO (Solid-Phase Extraction) prepacked column for efficient removal of interferents and concentration of NEOs. Quantification was conducted with a reverse-phase high-performance liquid chromatography (HPLC) system equipped with a Kinetex C18 column and a Diode Array Detector (DAD). This approach, leveraging STRATA XPRO cartridges, enabled faster processing and delivered high recovery rates. To validate the method, we applied the accuracy profile strategy endorsed by the Commission of the Société Française des Sciences et Techniques Pharmaceutiques (SFSTP) to assess the entire analytical procedure. Results demonstrated recoveries between 70% and 110%, a strong linear correlation between observed and predicted values (R2 = 0.999), a quantification limit exceeding the target NEO concentrations, accuracy below 10% (complying with European Commission standards), and over 95% of results falling within ±15% of the acceptance limits. The method's low cost, speed, and operational simplicity support its use for routine analysis
Detection of endocrine-disrupting chemicals in milk
Full text linkPlastic packaging, while offering significant societal and economic advantages, also contributes to global pollution and presents health hazards. Additives such as alkylphenols (APs) can disrupt endocrine functions even at minimal concentrations. Consequently, it is essential validate analytical methods for their measurement in food products. This study successfully validated a chromatographic technique for quantifying alkylphenols (specifically mono-ethoxylate, 4-n-octylphenol, 4-tert-octylphenol, 4-n-octylphenol, and 4-n-nonylphenol) in milk. The analytical approach employs solid-liquid extraction (SLE) to mitigate matrix effects, followed by reverse phase chromatography combined with a Diode Array Detector (DAD) for the quantification of alkylphenols. Validation was conducted using accuracy profiling, a straightforward decision-making tool that assesses the total error of the method, including both bias and standard deviation. The validation results indicated no interfering peaks at the retention times of the APs, a strong linear correlation between the independent variables in the regression model and the dependent variable (with linear regression coefficients approximately equal to 1), excellent precision across various concentration levels for both intra-day and inter-day measurements, and systematic and random errors falling within the predefined acceptable limits (± 10%). The method's minimal environmental impact and simplicity of execution recommend it for routine analytical applications
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
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