1,721,024 research outputs found
Studio del processo biologico via nitrito applicato a reflui a basso carico di azoto
Full text linkLa crescente attenzione per la ricerca di nuovi processi di trattamento delle acque reflue persegue l’obbiettivo di combinare il raggiungimento di alti standard di qualità nell’effluente, la riduzione dei inquinanti rilasciati direttamente o indirettamente nell’atmosfera e il recupero di energia e di preziose materie prime dalle acque di scarico. Le prestazioni del processo via nitrito per il trattamento di reflui a basso contenuto di azoto sono state valutate su un pilota da 3 m3, alimentato con acqua reflua reale di origine urbana, al fine di comprendere i meccanismi che favoriscono l’avvio e la stabilità del processo. Studiando selettivamente la combinazione dei diversi parametri in gioco si è cercato di evidenziare quelli che maggiormente incidono sulle prestazioni del processo, cercando di velocizzare la fase di startup e ridurre progressivamente il dosaggio dei reagenti esterni necessari per il condizionamento della biomassa. La sperimentazione è stata suddivisa in tre parti, ognuna corrispondente a una configurazione di lavoro diversa. Ogni configurazione è stata preceduta da studi preliminari in laboratorio per poi passare alla validazione dei risultati ottenuti in scala dimostrativa. Inoltre, durante le fasi in scala pilota, attraverso il monitoraggio in continuo delle emissioni gassose si è cercato di comprendere i meccanismi di formazione e rilascio in atmosfera degli off-gasses, incentrando l’attenzione soprattutto sul protossido di azoto (N2O). Attraverso il monitoraggio delle costanti cinetiche si è messa in luce una notevole differenza di efficacia delle prestazioni in funzione della strategia d’inibizione adottata, passando da un processo stabilmente sopra al 90% via nitrito nella configurazione iniziale a percentuali intorno al 10% durante il condizionamento sull’influente. Le condizioni applicate per l’inibizione dei batteri nitrificanti e il lungo mantenimento delle condizioni di inibizione della biomassa ha permesso di ottenere una notevole crescita delle velocità di nitritazione permettendo di raggiungere un notevole decremento in termini di protossido di azoto rilasciato.The growing attention to the research of new wastewater treatment processes pursues the objective of combine the achievement of high quality standards in the effluent, the reduction of pollutants released directly or indirectly into the atmosphere and the recovery of energy and precious raw materials from wastewater. The performances of the via nitrite process for the treatment of low strength of nitrogen wastewater was evaluated on a 3 m3 pilot plant, fed with real urban wastewater, in order to understand the mechanisms that promote the start-up and stability of the process. Studying selectively the combination of the different parameters involved, we tried to highlight those that most affect the performance of the process, trying to speed up the start-up phase and progressively reduce the dosage of the external reagents needed for the biomass conditioning. The experimentation was divided in three parts, each corresponding to a different work configuration. Each configuration was preceded by preliminary studies in the laboratory and then the results obtained were validated on the demonstrative scale. Moreover, during the pilot scale phases, through the continuous monitoring of gaseous emissions, we tried to understand the mechanisms of formation and release into the atmosphere of off-gasses, focusing the attention on nitrous oxide (N2O). Through the monitoring of the kinetic constants, a considerable difference in terms of performance has been highlighted according to the inhibition strategy adopted, moving from a stable 90% via nitrite process in the initial configuration to around 10% during the conditioning of the influent flow. The conditions applied for the inhibition of nitrifying bacteria and the long maintenance of the biomass inhibition have allowed a remarkable increase in nitrite speeds, allowing a considerable decrease in the amount of nitrous oxide released
BIOLOGICAL TREATMENT VIA NITRITE OF ANAEROBIC SUPERNATANTS FROM LIVESTOCK AND AGRO WASTES: PERFORMANCES AND KINETIC RATES
No full textGreenhouse Gases Emissions From Continuous Process For Treatment Of Urban Wastewater Via Nitrite
No full textTherapeutic potential of stem cell-derived extracellular vesicles in neurodegenerative diseases associated with cognitive decline
No full text: In the central nervous system, cell-to-cell interaction is essential for brain plasticity and repair, and its alteration is critically involved in the development of neurodegenerative diseases. Neural stem cells are a plentiful source of biological signals promoting neuroplasticity and the maintenance of cognitive functions. Extracellular vesicles (EVs) represent an additional strategy for cells to release signals in the surrounding cellular environment or to exchange information among both neighboring and distant cells. In the last years, rising attention has been devoted to the ability of stem cell (SC)-derived EVs to counteract inflammatory and degenerative brain disorders taking advantage of their immunomodulatory capacities and regenerative potential. Here, we review the role of adult neurogenesis impairment in the cognitive decline associated with neurodegenerative diseases and describe the beneficial effects of SC-derived EVs on brain plasticity and repair also discussing the advantages of SC-derived EV administration versus SC transplantation in the treatment of neurodegenerative disorders
Production of greenhouse gases from biological activated sludge processes: N2O emission factors and influences of the sampling methodology
No full text
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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