1,720,956 research outputs found
Human Health Risk Assessment of a pilot-plant for catalytic pyrolysis of mixed waste plastics for fuel production
No full textDioxins, PCBs and VOCs are the main hazardous chemicals emitted by gaseous streams from catalytic pyrolysis of waste plastics. In this work we propose a methodology to assess toxic and cancer risk under uncertainty, due to inhalation and ingestion of these chemicals by considering complex scenarios, as repeated start-ups and short continuous operation that may occur in a pilot-plant. Different simulation tools are combined to evaluate the expected concentration of pollutants in the environmental compartments and food. Hazard Index and Cancer Risk remain under the threshold for both dioxins (HI < 0.012, CR < 5.03 10−7) and PCBdl (HI < 1.3 10−7, CR < 2.49 10−12) in all the simulated scenarios, also for the worst case of children ingesting vegetables and meat and uncertainty factors up to 1000. Different results are obtained for VOCs since repeated leakages during the pilot-plant operation are possible. All the risk indexes for benzene are under the threshold (HI < 0.175, CR < 1.41 10−7); acute toxic risk due to inhalation and cancer risk due to ingestion of grain/vegetables are over the threshold if all the uncertainties are considered. Lesson learned: HHRA is important also during scale-up; pilot-plants for pyrolysis of waste plastics must always be equipped with all the abatement systems designed for the final plant
Spatiotemporal role of muscarinic signaling in early chick development: exposure to cholinomimetic agents by a mathematical model
No full textAwareness is growing that, besides several neurotoxic effects, cholinomimetic drugs able to interfere the cholinergic neurotransmitter system may exert a teratogen effect in developing embryos of vertebrate and invertebrate organisms. Cholinomimetic substances exert their toxic activity on organisms as they inhibit the functionality of the cholinergic system by completely or partially replacing the ACh molecule both at the level of the AChE active site and at the level of acetylcholine receptors. In this work, we focused the attention on the effects of muscarinic antagonist (atropine) and agonist (carbachol) drugs during the early development and ontogenesis of chick embryos. An unsteady-state mathematical model of the drug release and fate was developed, to synchronize exposure to a gradient of drug concentrations with the different developmental events. Since concentration measures in time and space cannot be taken without damaging the embryo itself, the diffusion model was the only way to establish at each time-step the exact concentration of drug at the different points of the embryo body (considered two-dimensional up to the 50 h stage). This concentration depends on the distance and position of the embryo with respect to the releasing source. The exposure to carbachol generally enhanced dimensions and stages of the embryos, while atropine mainly caused delay in development and small size of the embryos. Both the drugs were able to cause developmental anomalies, depending on the moment of development, in a time- and dose-dependent way, regardless the expression of genes driving each event
Controlled Combustion and Pyrolysis of Waste Plastics: A Comparison Based on Human Health Risk Assessment
No full textIncreasing conditions of economic and social well-being have led to an increase in waste production. Among the waste products, a significant portion consists of plastic materials that are popular in the components of consumer goods. For this reason, the conversion of plastic to energy via controlled combustion and plastic to fuel via thermal/catalytic pyrolysis or gasification can be proposed to treat the residual heterogeneous mixed plastics that cannot be recovered as individual polymers. The quality and type of fuels that are possible to obtain from these processes are different, as is the quality of their emissions, which generally contain VOCs, PCBs, dioxins, PAHs, and heavy metals. In this work, we propose a methodology based on human health risk assessment to compare controlled combustion and catalytic pyrolysis. Many pathways are analyzed, and pollutant concentrations are computed in the atmosphere, water, vegetables, fish, and food. Exposure is evaluated for inhalation and ingestion routes by taking into account uncertainties. Our results show that the risk profile of catalytic pyrolysis is low. Controlled combustion remains an interesting process, but even if Best Available Technologies (BAT) are adopted, the cancer risk due to PAHs contained in particulate is around the threshold for people living near the plant if a long period of operation is considered
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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