1,721,005 research outputs found
Role of the chronic air pollution levels in the Covid-19 outbreak risk in Italy
Full text linkAfter the initial outbreak in China, the diffusion in Italy of SARS-CoV-2 is exhibiting a clear regional trend
with more elevated frequency and severity of cases in Northern areas. Among multiple factors possibly
involved in such geographical differences, a role has been hypothesized for atmospheric pollution. We
provide additional evidence on the possible influence of air quality, particularly in terms of chronicity of
exposure on the spread viral infection in Italian regions. Actual data on Covid-19 outbreak in Italian
provinces and corresponding long-term air quality evaluations, were obtained from Italian and European
agencies, elaborated and tested for possible interactions. Our elaborations reveal that, beside concentrations, the chronicity of exposure may influence the anomalous variability of SARS-CoV-2 in Italy. Data
on distribution of atmospheric pollutants (NO2, O3, PM2.5 and PM10) in Italian regions during the last 4
years, days exceeding regulatory limits, and years of the last decade (2010e2019) in which the limits
have been exceeded for at least 35 days, highlight that Northern Italy has been constantly exposed to
chronic air pollution. Long-term air-quality data significantly correlated with cases of Covid-19 in up to
71 Italian provinces (updated April 27, 2020) providing further evidence that chronic exposure to atmospheric contamination may represent a favourable context for the spread of the virus. Proinflammatory responses and high incidence of respiratory and cardiac affections are well known,
while the capability of this coronavirus to bind particulate matters remains to be established. Atmospheric and environmental pollution should be considered as part of an integrated approach for sustainable development, human health protection and prevention of epidemic spreads but in a long-term
and chronic perspective, since adoption of mitigation actions during a viral outbreak could be of limited
utility
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
Hyperaccumulation of vanadium in the Antarctic polychaete Perkinsiana littoralis as a natural chemical defense against predation
No full textExceptionally high levels of trace metals have been reported in specific tissues of certain polychaetes. In the present
study, the Antarctic fan worm Perkinsiana littoralis was shown to hyperaccumulate vanadium in the branchial tissues, and the
hypothesis of an antipredatory strategy has been investigated
Trace metals (Ag, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, Zn) were measured by atomic absorption
spectrophotometry in tissues of P. littoralis and, only for V, in two Antarctic bivalves and in various Mediterranean polychaetes.
Subcellular distribution of vanadium was investigated in P. littoralis after differential centrifugations; feeding trials with the
Antarctic rock cod Trematomus berancchii were performed to test the palatability of P. littoralis
Analyses of trace metals in tissues of P. littoralis confirmed the naturally high bioavailability of cadmium due to upwelling
phenomena in the investigated area and revealed extremely high concentrations of vanadium up to 10,000 A mu g/g, in the branchial
crowns; much lower concentrations were measured in the body portions and even less in the Antarctic bivalves and in
Mediterranean polychaetes. The subcellular distribution indicated that this metal was associated in branchial crowns with both
heavy components and vanadium binding proteins; the latter predominated in body tissues, although with a different pattern of
molecular weight. Feeding trials suggested that the elevated levels of vanadium in branchial crown of P. littoralis act as chemical
deterrents against predation in more exposed tissues
The hyperaccumulation of toxic metals might represent a common antipredatory strategy for unpalatable branchial crowns of
sabellid polychaetes, as recently hypothesized also for the high concentrations of arsenic in the Mediterranean Sabella spallanzanii.
The evolution of such adaptation and the reasons behind the possibility for different species to accumulate different metals represent
a stimulating field of investigation for future studies
Oxidative and interactive challenge of cadmium and ocean acidification on the smooth scallop Flexopecten glaber.
Full text linkOcean acidification (OA) may affect sensitivity of marine organisms to metal pollution modulating chemical bioavailability, bioaccumulation and biological responsiveness of several cellular pathways. In this study, the smooth scallop Flexopecten glaber was exposed to various combinations of reduced pH (pH/pCO2 7.4/∼3000 μatm) and Cd (20 μg/L). The analyses on cadmium uptake were integrated with those of a wide battery of biomarkers including metallothioneins, single antioxidant defenses and total oxyradical scavenging capacity in digestive gland and gills, lysosomal membrane stability and onset of genotoxic damage in haemocytes. Reduced pH slightly increased concentration of Cd in scallop tissues, but no effects were measured in terms of metallothioneins. Induction of some antioxidants by Cd and/or low pH in the digestive gland was not reflected in variations of the total oxyradical scavenging capacity, while the investigated stressors caused a certain inhibition of antioxidants and reduction of the scavenging capacity toward peroxyl radical in the gills. Lysosomal membrane stability and onset of genotoxic damages showed high sensitivity with possible synergistic effects of the investigated factors. The overall results suggest that indirect effects of ocean acidification on metal accumulation and toxicity are tissue-specific and modulate oxidative balance through different mechanisms
Effects of ocean warming and acidification on accumulation and cellular responsiveness to cadmium in mussels Mytilus galloprovincialis: Importance of the seasonal status
Full text linkOcean warming and acidification could represent an additional threat to marine organisms already coping with other anthropogenic impacts, such as chemical contamination in coastal areas. In this study, interactions between such multiple stressors and their synergistic effects in terms of accumulation, detoxification and biological effects of metals were investigated in the Mediterranean mussel Mytilus galloprovincialis. Organisms sampled during the winter period were exposed for 28 days to different combinations of two temperatures (10 degrees C and 15 degrees C), two pH/pCO(2) (8.20/ similar to 400 mu atm and 7.4/ similar to 3000 mu atm) and two cadmium concentrations (0 and 20 mu g/L). Cadmium concentrations increased in digestive glands and gills of metal-exposed mussels and were further enhanced by co-exposure at higher temperature. Interactive effects of temperature and/or pH were observed on Cd-mediated metallothionein induction, responsiveness of antioxidant system and onset of oxidative damages in lipids, with tissue-specific effects. Immunological effects showed a generalized sensitivity of lysosomal membrane stability toward the investigated stressors with major effects in co-exposed organisms. Cadmium and temperature affected phagocytosis efficiency and composition of haemocyte populations probably influencing the micronucleus frequency through varied mitotic rate. Several differences were highlighted between these results and those previously obtained from mussels exposed in summer, supporting the importance of season when addressing the tolerance of temperate organisms to variations of environmental factors. The elaboration of the whole biomarker results through weighted criteria allowed to summarize specific hazard indices, highlighting tissue-specific sensitivity toward multiple stressors and the need of improving the knowledge on interactions between multiple stressors
Human pharmaceuticals in marine mussels: Evidence of sneaky environmental hazard along Italian coasts
Full text linkDespite the increasing interest for pharmaceuticals in the marine environment, their accumulation in wild organisms and consequent environmental hazards are still poorly known. The Mediterranean Sea is highly challenged by the density of coastal populations, large consumption of pharmaceuticals and their often limited removal by Wastewater Treatment Plants (WWTPs). In this respect, the present study aims to provide the first large-scale survey on the distribution of such contaminants of emerging concern in native mussels, Mytilus galloprovincialis from Italian coasts. Organisms were collected from 14 sites representative of relatively unpolluted marine waters along the Adriatic and Tyrrhenian Sea and analysed for 9 common pharmaceuticals including Non-Steroidal Anti-Inflammatory Drugs (NSAIDs: Diclofenac DIC, Ibuprofen IBU, Ketoprofen KET and Nimesulide NIM), the analgesic Acetaminophen AMP, the antiepileptic Carbamazepine CBZ, the antihypertensive Valsartan VAL, the anxiolytic Lormetazepam LOR and the antidepressant Paroxetine PAR. Results indicated the widespread occurrence of the majority of pharmaceuticals in mussel tissues: CBZ was measured in >90% of analysed samples, followed by VAL (>50%), PAR (>40%), and DIC (>30%), while only AMP and KET were never detected. Heterogeneous tissue concentrations ranged from a few units up to hundreds of ng/g (d.w.), while seasonal and interannual variability, investigated over 4 years, did not highlight any clear temporal trend. Limited differences obtained between the Adriatic and Tyrrhenian Sea, as well as coastal versus off-shore sampling sites, suggest that analysed levels of pharmaceuticals in mussels tissues should be considered as baseline concentrations for organisms collected in unpolluted areas of the Mediterranean. This study provided the first unambiguous evidence of the widespread occurrence of pharmaceuticals in marine mussels from Italian coasts, giving novel insights on the potential ecotoxicological hazard from such compounds in marine species
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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