1,720,956 research outputs found
Radioactivity measurements in water: An overview of the actual technologies
No full textAmong the most significant matrices in the field of environmental radioactivity, water is certainly included, being subject to monitoring and controls to safeguard the environment from pos-sible anthropogenic contamination. The presence of radionuclides in water also constitutes a health risk to human, because its consumption increases the likelihood of incurring cancer. In authors’ laboratory, different experimental techniques were employed to measure radioactivity content of surface and drinking water, according to the Italian Legislation and to the Italian Institute for the Environmental Protection and Research (ISPRA) guidelines. Gamma spectrometry was employed to quantify the specific activity of gamma-emitters anthropogenic contaminants and natural radionuclides; liquid scintillation counting (LSC), to measure the activity concentration of triti-um, radon and gross alpha and beta; total alpha/beta counting, with the thick source method, to de-tect about gross alpha and beta specific activity; emanometry, to estimate gas radon activity concen-tration
Radioattività nelle acque superficiali e potabili: overview delle attuali tecniche sperimentali
No full textRadioactivity and heavy metals concentration in Italian (Calabrian) DOC wines
No full textWine is an alcoholic drink, largely used to accompany food, with a key role in the protective effects on cardiovascular diseases. This study was developed to investigate radioisotopes and heavy metal content of twenty red, rose and white Italian wines, belonging to controlled origin denomination (DOC) geographic areas of the Calabria region, south of Italy. High Purity Germanium (HPGe) Gamma Spectrometry was employed to evaluate anthropogenic (137Cs) and natural (40K) radionuclides specific activity. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to assess any possible heavy metals contamination by a comparison between Cu, Zn, Pb, B, As and Cd concentrations with the limits set by the Italian Legislation. Calculated annual effective doses due to the ingestion of investigated samples are under allowable levels (1 mSv/year), thus excluding the risk of ionizing radiation effects on humans. Regarding to the metals concentration, experimental results show that they are lower than the contamination threshold values, thus excluding their presence as pollutants
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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