1,720,984 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
Bacterial histidine kinases : study of the conformational changes and structural determinants involved in the autokinase reaction
No full textLos sistemas de dos componentes son una parte vital de la adaptación a estímulos ambientales en microorganismos. Estos están compuestos por un componente histidinkinasa el cual, ante la señal correspondiente, se autofosforila y luego transfiere el fosfato al componente regulador de respuesta. El regulador de respuesta se encarga a su vez de desencadenar la respuesta adaptativa, uniéndose al ADN y actuando como factor de transcripción. Las histidinkinasas generalmente actúan en forma de dímero. Debido a esto, existen dos mecanismos posibles para la autofosforilación: En cis o intramolecular, en el cual una unidad se fosforila a si misma y en trans o intermolecular, en el cual una unidad fosforila a la opuesta. Cada histidinkinasa se autofosforila exclusivamente por uno de los dos mecanismos, ya que cada mecanismo se corresponde con una organización estructural distinta en la superficie de dimerización. Existe evidencia de que cual de estos mecanismos utiliza una histidinkinasa dada estaría determinado por un loop que conecta las dos hélices que forman la superficie de dimerización, pero no se conocen los detalles de cómo es que este loop repercute sobre el plegado de estas hélices. En este trabajo exploramos varios aspectos de la reacción autokinasa. En primer lugar, estudiamos mediante técnicas computacionales las diferencias entre los loops de histidinkinasas de mecanismo cis y trans. Además, mediante el empleo del programa AlphaFold pudimos modelar las estructuras de cientos de histidinkinasas y mutantes de las mismas para expandir la información disponible. En segundo lugar, utilizamos técnicas bioquímicas para determinar el mecanismo cis/trans de dos histidinkinasas de mecanismo desconocido, DesK y DosS. Estas histidinkinasas pertenecen a la familia HisKA_3, para la cual existe muy poca información bioquímica y estructural, por lo que constituye un aporte significativo al estudio de las histidinkinasas. Finalmente mediante técnicas computacionales estudiamos la transición conformacional del estado inactivo al activo de una histidinkinasa, caracterizando los cambios químicos que se dan sobre la histidina fosforilable a lo largo de esta transición. Además, utilizando simulaciones a nivel cuántico caracterizamos la transferencia del fosfato hacia la histidina.Two-component systems are a vital part of adaptation to stimuli in microorganisms. These are composed by a histidine kinase component which phosphorylates in response to the appropriate signal and then transfers the phosphate to the response regulator component. The response regulator then triggers the adaptive response, binding to DNA and acting as a transcription factor. Histidine kinases generally act as a dimers. Because of this there are two possible autophosphorylation mechanisms: En cis or intramolecular, in which one unit phosphorylates itself, and in trans or intermolecular in which un unit phosphorylates the other. Each histidine kinase autophosphorylates exclusively through one or the other, since each mechanism corresponds to a different structural organization in the dimerization surface. It is known that which mechanisms a histidine kinase uses is determined by a loop connecting the two helices that form the dimerization surface, but the details on how this loop affects the folding of these helices is not known. In this work we explore several aspects of the autokinase reaction. First we studied by computational means the differences between cis and trans histidine kinases. Through the use of AlphaFold we modeled hundreds of histidine kinases and mutants of these in order to expand the available structural information. We also used biochemical techniques to determine the autophosphorylation mechanism of two histidine kinases, DesK and DosS. These histidine kinases belong to the HisKA_3 family for which there is very little biochemical and structural information, therefore significantly expanding the available knowledge. Finally we studied through computational means the conformational transition from the inactive to the active state characterizing the chemical changes that occur to the phosphorylatable histidine as this transition progresses. Using quantum-level simulations we characterized the phosphate transfer to the histidine.Fil: Olivieri, Federico Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
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
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
Cellulose Isolation from Tomato Pomace: Part II—Integrating High-Pressure Homogenization in a Cascade Hydrolysis Process for the Recovery of Nanostructured Cellulose and Bioactive Molecules
No full text: This work proposes a biorefinery approach for utilizing tomato pomace (TP) through a top-down deconstructing strategy, combining mild chemical hydrolysis with high-pressure homogenization (HPH). The objective of the study is to isolate cellulose pulp using different combinations of chemical and physical processes: (i) direct HPH treatment of the raw material, (ii) HPH treatment following acid hydrolysis, and (iii) HPH treatment following alkaline hydrolysis. The results demonstrate that these isolation routes enable the production of cellulose with tailored morphological properties from TP with higher yields (up to +21% when HPH was applied before hydrolysis and approximately +6% when applied after acid or after alkaline hydrolysis). Additionally, the side streams generated by this cascade process show a four-fold increase in phenolic compounds when HPH is integrated after acid hydrolysis compared to untreated sample, and they also contain nanoparticles composed of hemicellulose and lignin, as shown by FT-IR and SEM. Notably, the further application of HPH treatment enables the production of nanostructured cellulose from cellulose pulp derived from TP, offering tunable properties. This approach presents a sustainable pathway for the extraction of cellulose and nanocellulose, as well as the valorization of value-added compounds found in residual biomass in the form of side streams
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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