1,720,960 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Progress in bacterial cellulose matrices for biotechnological applications
Get PDFBacterial cellulose (BC) is an extracellular polymer produced by many microorganisms. The Komagataeibacter genus is the best producer using semi-synthetic media and agricultural wastes. The main advantages of BC are the nanoporous structure, high water content and free hydroxyl groups. Modification of BC can be made by two strategies: in-situ, during the BC production, and ex-situ after BC purification. In bioprocesses, multilayer BC nanocomposites can contain biocatalysts designed to be suitable for outside to inside cell activities. These nanocomposites biocatalysts can (i) increase productivity in bioreactors and bioprocessing, (ii) provide cell activities does not possess without DNA cloning and (iii) provide novel nano-carriers for cell inside activity and bioprocessing. In nanomedicine, BC matrices containing therapeutic molecules can be used for pathologies like skin burns, and implantable therapeutic devices. In nanoelectronics, semiconductors BC-based using salts and synthetic polymers brings novel films showing excellent optical and photochemical properties.Fil: Cacicedo, Maximiliano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; ArgentinaFil: Castro, M. Cristina. Universidad Pontificia Bolivariana; ColombiaFil: Servetas, Ioannis. University of Patras; GreciaFil: Bosnea, Loulouda. University of Patras; GreciaFil: Boura, Konstantina. University of Patras; GreciaFil: Tsafrakidou, Panagiota. University of Patras; GreciaFil: Dima, Agapi. University of Patras; GreciaFil: Terpou, Antonia. University of Patras; GreciaFil: Koutinas, Athanasios. University of Patras; GreciaFil: Castro, Guillermo Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentin
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
Organic acids production from cellulosic biomass using kissiris as promoter
No full textIn this doctoral thesis the aim was to find the optimum conditions for the production of volatile fatty acids and ethanol through the process of anaerobic digestion in the presence of the mineral kissiris as promoter. The experiments for the study of acidogenesis were initially carried out using a synthetic glucose medium as substrate. The effect of initial pH of the fermentation substrate (3, 4, 5, 6, 7, 8 and 9), the sugar concentration (30, 50, and 70 g/L) and the fermentation temperature (30, 37 and 52°C) were studied. These experiments were preformed with the use of both free cells of the mixed UASB anaerobic culture and cells immobilized on kissiris in order to study the effect of the promoter. The total acid production was higher at pH 9, 37oC, and 30 g/L substrate concentration. The lignocellulosic material was studied next. Initially, the effect of the presence of kissiris on batch fermentations of chemically delignified straw, were studied. These fermentations were carried out for 48 h, at 37°C, 30 g/L straw concentration, and initial pH 7, 8 and 9, for comparison reasons. Ethanol production was at 0.2 mL/L while the acids produced were mainly lactic (4.5-5.3 g/L), as well as succinic and acetic in smaller quantities (1 and 1.5 g/L, respectively). Repeated batch fermentations were then performed at initial pH 7, 8 and 9, 37oC, and straw concentration 30 g/L, in the presence and absence of kissiris. The fermented liquids were replenished every 9 h with a nutrient solution identical to that used for the fermentation but without the addition of straw. Acid production was observed for 4 repeated batches. Subsequently, the continuous fermentation of glucose was studied. The continuous operation of the reactor lasted 97 days and three different concentrations of glucose at initial pH 9 and 37°C were tested. Initially, the system was pumped with nutrient medium containing 70 g/L glucose, the concentration of which gradually decreased to 30 g/L. The continuous fermentation gave high concentrations of organic acids reaching up to 15.2 g/L. For the continuous anaerobic straw fermentation in the presence of kissiris, the same experimental arrangement was used but the reactor was opened to fill with a 30 g/L straw solution, and then feeding was done with synthetic medium that did not contain any straw. This fermentation produced acids for 10 days, mainly acetate and butyrate. Subsequently, scale-up experiments were performed using a 82 L volume bioreactor using kissiris as promoter. Two volumes of 17 L and 40 L were studied. The production of organic acids reached 17.2 g/L and consisted mainly of butyric and acetic acid. Finally, the recovery of organic acids from the fermentation broths was studied by liquid-liquid extraction using various organic solvents. The experiments were carried out in standard aqueous solutions but also in fermentation broths of delignified straw. Of all the solvents tested, butanol-1 was chosen as the best solvent for this particular application in terms of extraction yields and process cost. Regarding the acid extraction from the fermentation broths, the results were similar to those of the standard organic acid solutions. In particular, the best results were obtained at pH 1 with butanol-1 (almost 80% total recovery).Στην παρούσα διδακτορική διατριβή ο στόχος ήταν η εύρεση των βέλτιστων συνθηκών για την παραγωγή πτητικών λιπαρών οξέων (ΟΑ) και αιθανόλης μέσω της διεργασίας της αναερόβιας χώνευσης, υπό παρουσία ενός προωθητή της βιοδιεργασίας όπως είναι η κίσσηρης. Αυτά τα οξέα θα μπορούν να χρησιμοποιηθούν για την παραγωγή νέας γενιάς βιοκαυσίμου ή για άλλες εφαρμογές. Τα πειράματα για τη μελέτη της οξεογένεσης έγιναν αρχικά σε συνθετικό μέσο γλυκόζης. Μελετήθηκε η επίδραση της αρχική τιμής pH του υποστρώματος ζύμωσης (3, 4, 5, 6, 7, 8 και 9), η συγκέντρωση του σακχάρου (30, 50, και 70 g/L) και η θερμοκρασία της ζύμωσης (30, 37 και 52oC). Τα πειράματα αυτά έγιναν τόσο με τη χρήση ελεύθερων κυττάρων της μικτής αναερόβιας καλλιέργειας UASB όσο και με τη χρήση ακινητοποιημένων κυττάρων σε κίσσηρη για να μελετηθεί η επίδραση του προωθητή. Η συνολική παραγωγή οξέων ήταν υψηλότερη στο αρχικό pH 9, θερμοκρασία 37oC ενώ η καλύτερη συγκέντρωση ήταν τα 30 g/L. Στη συνέχεια πραγματοποιήθηκε ξεκίνησε η μελέτη της οξεογένεσης του λιγνινοκυτταρινούχου αποβλήτου. Αρχικά μελετήθηκε η επίδραση της παρουσίας της κίσσηρης σε ζυμώσεις διαλείποντος έργου (batch) σε χημικώς απολιγνινοποιημένο άχυρο. Οι ζυμώσεις αυτές έγιναν στους 37 οC σε συγκέντρωση 30 g/L απολιγνινοποιημένου άχυρου και δοκιμάστηκαν οι αρχικές τιμές pH 7, 8, και 9 για λόγους σύγκρισης και διήρκησαν 48 h. Η παραγωγή αιθανόλης ήταν στα 0,2 mL/L ενώ από τα οξέα παράχθηκε κυρίως γαλακτικό (4,5–5,3 g/L), ηλεκτρικό και οξικό σε μικρότερες ποσότητες (1 και 1,5 g/L, αντίστοιχα). Στη συνέχεια πραγματοποιήθηκαν επαναλαμβανόμενες ζυμώσεις διαλείποντος έργου σε αρχικές τιμές pH 7, 8, και 9 σε αρχική συγκέντρωση άχυρου 30 g/L σε θερμοκρασία 37oC παρουσία και απουσία κίσσηρης. Tα ζυμωμένα υγρά αναπληρωνόντουσαν κάθε 9 ώρες με θρεπτικό διάλυμα ίδιο με αυτό που χρησιμοποιήθηκε για τη ζύμωση αλλά χωρίς την προσθήκη άχυρου. Παρατηρήθηκε παραγωγή οξέων για 4 επαναλαμβανόμενα batch. Στη συνέχεια μελετήθηκε η συνεχής ζύμωση της γλυκόζης. Η συνεχής λειτουργία του αντιδραστήρα διήρκησε 97 μέρες και δοκιμάστηκαν 3 διαφορετικές συγκεντρώσεις γλυκόζης με αρχικό pH 9 και θερμοκρασία 37oC. Αρχικά στο σύστημα παροχετεύθηκε με θρεπτικό υγρό που περιείχε 70 g/L γλυκόζη του οποίου η συγκέντρωση σταδιακά μειώθηκε στα 30 g/L. Η συνεχής ζύμωση έδωσε συγκεντρώσεις οργανικών οξέων που έφτασαν μέχρι τα 15,2 g/L. Για τη συνεχή αναερόβια ζύμωση άχυρου παρουσία κίσσηρης χρησιμοποιήθηκε η ίδια πειραματική διάταξη, ο αντιδραστήρας ανοίχθηκε ώστε να πληρωθεί με διάλυμα άχυρου 30 g/L, ενώ έγινε τροφοδοσία με συνθετικό υγρό χωρίς άχυρο. Η ζύμωση αυτή έδωσε οξέα για 10 μέρες, κυρίως οξικό και βουτυρικό. Στη συνέχεια έγιναν πειράματα σε μεγάλη κλίμακα (scale-up) χρησιμοποιώντας βιοαντιδραστήρα όγκου 82 L με χρήση κίσσηρης ως προωθητή. Μελετήθηκαν 2 όγκοι 17 L και 40 L. Η παραγωγή οργανικών οξέων έφτασε τα 17,2 g/L και αποτελούνταν κυρίως από βουτυρικό και οξικό οξύ. Τέλος μελετήθηκε η ανάκτηση των οργανικών οξέων από τα υγρά ζύμωσης με τη χρήση οργανικών διαλυτών με τη μέθοδο της υγρής-υγρής εκχύλισης. Τα πειράματα έγιναν σε πρότυπα υδατικά διαλύματα αλλά και σε υγρά ζύμωσης απολιγνινοποιημένου άχυρου. Από τους διαλύτες που δοκιμάστηκαν η βουτανόλη-1 επιλέχθηκε ως ο καλύτερος διαλυτής για τη συγκεκριμένη εφαρμογή από άποψη απόδοσης εκχύλισης και κόστους. Όσον αφορά στην εκχύλιση των οξέων από τα υγρά της ζύμωσης τα αποτελέσματα ήταν ανάλογα με αυτά των πρότυπων διαλυμάτων. Πιο συγκεκριμένα τα καλύτερα αποτελέσματα ελήφθησαν για αρχικό pH 1 με διαλύτη τη βουτανόλη-1 (σχεδόν 80% συνολική παραλαβή)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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