1,721,025 research outputs found
Effetti delle dimensioni delle navi sulle emissioni delle flotte container e passeggeri // Effects of ships’ dimension on emissions of container and cruise fleets
No full textThe paper approaches freight and passengers fleets, affected by naval gigantism, to investigate its energetic and environmental effects. Among the emerging trends, we encounter the increase of the installed power and, more relevantly, of the transport capacity of the ships. The result is a decrease of the specific power, particularly in the last 20 years. In the same period, an increase of the performances of ships in terms of environmental and energetic sustainability is ongoing. A further acceleration in this direction could come from the introduction of less pollutant fuels and renewable energies. It is a pillar for the development of future sustainable fleets, with relevant emerging investigation needs. In this context, the paper proposes a synthetic approach, combining dimensions and environmental performances of ships, tested on container and cruises fleets in operation in selected worldwide most frequented locations. The results could be useful to check effective policies, basing on emerging technologies and implementation of new rules and regulation
Gut microbiota and health: connecting actors across the metabolic system
No full textOverweight-related metabolic diseases are an important threat to health in the Western world. Dietary habits are one of the main causative factors for metabolic syndrome, CVD and type 2 diabetes. The human gut microbiota is emerging as an important player in the interaction between diet and metabolic health. Gut microbial communities contribute to human metabolism through fermentation of dietary fibre and the result of intestinal saccharolytic fermentation is production of SCFA. Acetate, propionate and butyrate positively influence satiety, endocrine system, glucose homeostasis, adipogenesis, lipid oxidation, thermoregulation, hepatic gluconeogenesis, endothelial function and gut barrier integrity, and these mechanisms have all been linked to protection from type 2 diabetes, hypertension and cardiovascular health. The gut microbiota is also involved in bile acid metabolism and regulating their cell signalling potential, which has also been shown to modify pathways involved in metabolic health. Similarly, the gut microbiota renders recalcitrant plant polyphenols into biologically active small phenolic compounds which then act systemically to reduce metabolic disease risk. This review summarises how dietary patterns, specific foods and a healthy lifestyle may modulate metabolic health through the gut microbiota and their molecular cross-talk with the host
Immuno-modulatory effects of microbial metabolites of flavan-3-ols and dimeric procyanidins
No full textObjective: The gut microbiota is recognised to impact on human immune function, but we still know little about the immuno-modulating abilities of specific metabolites derived from microbiota biotransformation of dietary components. The present research aimed to evaluate the potential of microbially-derived metabolites of flavan-3-ols and dimeric procyanidins on human immune function.
Methods: Peripheral blood mononuclear cells from healthy donors were subjected to stimulation with LPS in presence or absence of different microbial polyphenol metabolites. After 5 days, T cell proliferation was measured by means of CFSE staining. IL6 and IL1B gene expression was measured after 4 hours of stimulation by real-time PCR.
Results: The results showed the immuno-modulatory potential of flavon-3-ols and procyanidins bacterial metabolites. Hydroxyphenylacetic acid was able to decrease inflammatory gene expression induced by LPS. 3,4-dihydroxyphenylpropionic acid also presented a marked anti-inflammatory capabilities, reducing IL6 and IL1B gene expression and LPS-primed T cell response.
Conclusions: Those preliminary data indicate that small phenolic acids produced by the gut microbiota upon biotransformation of complex plant polyphenols display different capabilities to regulate the inflammatory response. This has important implications for measuring the metabolic output of the gut microbiome and for identifying the molecular basis of how foods rich in polyphenols actually mediate their purported health effects in humans
Integrating on-board authorisation measurements with in-service measurements and risk assessment towards more effective running dynamics approval
No full textIn-service wheel-rail contact force measurements are increasingly being performed with both on-board and wayside systems for various purposes, such as identifying problems on single vehicles (overloading and unbalance, wheel flats etc.) and enabling predictive maintenance of components. Such a wealth of measurements can be expected not only to fulfil their original purposes, but also to steadily fill in vehicle-track interaction knowledge gaps if properly exploited - e.g. with a big-data approach. One possible exploitation regards the authorisation to place rolling stock in service from the point of view of running dynamics. This issue is carefully addressed in European legislation and usually requires a significant extent of on-track testing. It is still widely considered a topic where significant cost reductions could be achieved without sacrificing safety, and a possible barrier to innovations such as active primary suspensions and steering. A number of research directions have been addressing this issue, first and foremost the use of virtual methods (Multi-Body Simulation) as a supplement to on-track testing. However, the process defined in the legislation opens the door to other possible improvements. It comprises as a key element “return of experience”, and although still essentially rule-based, is open to risk-based approaches such as that defined in the European Common Safety Method for Risk Assessment (CSM RA).
Having developed both on-board and wayside wheel-rail contact force measurement systems, the authors consider that the “return of experience” element may further be specified by taking into account, for a given type of rolling stock, the lateral forces and wheel loads that are increasingly being measured in actual service
Effects of passengers flows on regularity of metro services: case studies of Rome lines A and B
No full textThe regularity is a key performance in the operation of a metro service, because it is normally affecting a large set of secondary performances: e.g. punctuality, energy efficiency, economic efficiency and vehicles availability. Human behaviours are affecting the regularity, by introducing deviations between panned and actual times in various operational phases of metro services: e.g. dwelling times, acceleration/deceleration times, inversion times at terminus, headways themselves. The variability in passengers’ flows is one of the most relevant parameters affecting mainly dwelling times and finally headways themselves. In this framework, this paper is specifically presenting the results of experimental surveys on metro services operated in Rome (Lines A and B).
On these lines, it has been performed a systematic counting of passengers boarding and alighting in the most crowded stations, combined with simultaneous measurement of actual dwelling times and headways. The collected results have been analysed, cleaned by inconsistent data and statistically interrelated looking for significant trends to compare with the most consolidated theoretical models and to quantify the effects in line with the literature developments, including those by the authors themselves. Finally, the focus is on the most relevant quantitative outputs and the main identified and outlined
further research needs
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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