1,720,977 research outputs found
Mercury levels in Merluccius merluccius muscle tissue in the central Mediterranean Sea: Seasonal variation and human health risk
Full text linkIn this study we analysed total mercury (THg) levels in European hake (Merluccius merluccius) – an ecologically and commercially important species throughout the Mediterranean – caught in the northern and central Adriatic Sea. To the best of our knowledge, this is the first study evaluating THg levels in hake fillets in relation to ecological (season) and biological (body size, sex, sexual maturity, lipid content) parameters. THg levels in muscle showed no sex-related differences; in contrast, significant season-related differences were found in females, with higher levels in spring-summer compared with autumn-winter. No season-related differences were seen in males. A significant sex effect was found for body size and sexual maturity. Females showed a correlation between THg level and length, THg being significantly higher in mature compared with immature specimens. No significant sex effect was found for muscle lipid content, because a correlation between THg concentration and tissue lipids was found in both sexes. Since the mean THg concentration found in M. merluccius fillets (0.64 ± 0.29 mg kg−1 dry weight; range, 0.20–1.53) was consistently under the level set by EU regulations, this study demonstrates that European hake caught in the northern and central Adriatic is safe for human consumption
Unlocking the elemental signature of European tea gardens: Implications for tea traceability
Full text linkThis study presents a comprehensive analysis of the elemental profiles of tea leaves coming from plants grown in several European gardens, with a focus on the bioaccumulation of essential and potentially toxic trace elements in relation to processing and location of tea garden. Samples were collected from various gardens across Europe, including Portugal, the Azores, Germany, the Netherlands, and Switzerland. Elemental analysis was conducted on fresh tea leaves, dried leaves, and leaves processed for the production of green and black tea, along with soil samples from the root zones of tea plants. The results reveal no significant differences in elemental content based on the processing of tea leaves. However, distinct elemental profiles were observed among tea leaves of plants grown in gardens from different European regions. Utilizing chemometric and machine learning tools, the study highlights the potential of these elemental profiles for enhancing the traceability of tea products
Hg levels in marine porifera of Montecristo and Giglio Islands (Tuscan Archipelago, Italy)
Full text linkPorifera are filter-feeding organisms known to bioaccumulate different contaminants in their tissues. The presence of mercury (Hg) has been reported in different Mediterranean species, mainly collected in the southern coast of France. In the present study, mercury concentrations in the tissue of the sponges of Montecristo and Giglio, two islands of Tuscany Archipelago National Park (TANP), are presented for the first time. Analyses of total mercury content were performed by Direct Mercury Analyzer. Statistical differences have been reported in the Hg concentrations of species collected in both islands, but they do not appear related to the anthropic impacts of the islands. Among the collected species, a high intra-and inter-variability have been recorded, with Cliona viridis showing the lowest concentration (0.0167-0.033 mgkg-1 dry weight), and Chondrosia reniformis and Sarcotragus spinosulus the highest (0.57 ± 0.15 and 0.64 ± 0.01 mgkg-1 dry weight, respectively). The variability of Hg measured did not allow us to identify sponges as bioindicators of toxic elements. Anyway, these results improve knowledge on the ecosystem of the TANP, underlining the species-specificity of metal concentrations for Porifera, and providing additional data to address the main input of the Marine Strategy guidelines to protect coasts, seas and oceans
Mercury in honey from the Marche region (central Italy). Risk assessment from human consumption and its use as bioindicator of environmental pollution
No full textHoney is a natural product made by honeybees (Apis mellifera) from nectar or honeydew. It is a very popular and appreciated product all over the world as it represents a rapidly available energy source and exerts several beneficial properties for humans. However, it has been demonstrated that honey can be contaminated by potentially toxic elements (PTEs) of natural or anthropogenic origin. Among them, mercury (Hg) represents one of the most dangerous for its toxicity and its capacity to biomagnify along the trophic web. In the present study, 100 honey samples from the Marche Region (Central Italy) produced in the year 2021, were analyzed by thermal decomposition amalgamation atomic absorption spectrometry to determine the Hg content. The overall mean concentration was 0.2 ± 0.2 μg kg-1. The results showed that no statistically significant differences were found in Hg content among honey from different pollen origin, but honeydew had a significantly higher Hg content with respect to all other honey samples (0.6 ± 0.3 μg kg-1). The Hg content in honey depends mainly on local pollution, while geographical origin did not play a key role. Furthermore, considering the regulatory limits and provisional tolerable weekly intake (PTWIs) identified by FAO/WHO, the Hg Hazard Quotient (HQ) measurement revealed that this product is safe for human consumption
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
Insect-based aquafeeds modulate the fatty acid profile of zebrafish: A comparison on the different life stages
Full text linkInsects are considered as an alternative and sustainable ingredient for feed production. In this study, Hermetia illucens (Hi) prepupae (fed on coffee roasted by-product added with 10 % Schyzochytrium sp., a marine protist rich in polyunsaturated fatty acids) was processed into meal and included at graded levels in five experimental diets to replace dietary fish meal (0, 25, 50, 75, 100 %) offered to zebrafish (Danio rerio) as experimental model. The fatty acids (FAs) profile of fish larvae (20 days), juveniles (2 months, deprived of the viscera) and adults (6 months, male and female, deprived of the viscera) specimens was investigated to evaluate the impact of dietary FM replacement with full-fat Hi prepupae meal. For the first time, the quantification of FAs in Danio rerio, performed by gas chromatography-mass spectrometry, was computed in absolute terms (mg 100 g−1 dw), identifying the real variation in the content of any single FA. In fish, quantified total FAs in larvae, juvenile, adult male and adult female were 134 ± 2, 235 ± 8, 266 ± 3 and 266 ± 8 mg g−1 dw, respectively. With respect to zebrafish fed the control diet, specimens fed diet with increasing level of Hi prepupae meal showed significantly higher content of saturated and omega6 FAs, and significantly lower content of poly-unsaturated and omega3 FAs, reflecting partially the FAs composition of the administered diets. At the same time, the docosahexaenoic/eicosapentaenoic acid ratio increased significantly. Moreover, adult female showed a higher content of PUFA with respect to adult male, which could be justified by the needs of physiological reproductive processes. The principal component analysis demonstrated that the FAs composition in Danio rerio depends on both the life stage and the diet
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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