1,721,124 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
Metabolic engineering of Pichia pastoris for 3-hydroxypropionic acid production from glycerol
Get PDFL'àcid 3-hidroxipropiònic (3-HP), un producte plataforma, ha estat identificat com un dels productes de valor afegit més prometedors per ser obtinguts a partir de biomassa pel Departament d'Energia dels Estats Units. En conseqüència, en els darrers anys, els estudis centrats en la bioproducció de 3-HP han guanyat una atenció notable. Fins ara, s'ha informat de la producció de 3-HP per a la revalorització de múltiples fonts de carboni utilitzant diversos microorganismes. Aquesta tesi s'emmarca en un projecte per aconseguir produir 3-HP a partir de glicerol en Pichia pastoris (Komagataella phaffii). Aquest llevat metilotròfic és capaç de créixer consumint el glicerol cru provinent de la indústria del biodièsel i pot créixer a un pH baix, facilitant la posterior purificació del 3-HP. L'expressió de la via del malonil-CoA al 3-HP, codificada pel gen de la malonil-CoA reductasa (mcr) de Chloroflexus aurantiacus, en P. pastoris va donar lloc a la producció de 3-HP amb rendiments baixos (0.01 Cmol/Cmol, soca PpHP1). Posteriorment, estretègies d'enginyeria enzimàtica i metabòlica dirigides a augmentar la disponibilitat de cofactors i precursors metabòlics van permetre augmentar 14 vegades el rendiment de producció de 3-HP en comparació amb la soca inicial (0.14 Cmol/Cmol, soca PpHP6). En particular, aquest rendiment va ser lleugerament superior als que s'han descrit anteriorment utilitzant altres llevats que expressaven la mateixa via heteròloga, com Saccharomyces cerevisiae o Schyzosaccharomyces pombe (0.12 Cmol/Cmol en ambdós llevats). Això suggereix que el perfil Crabtree negatiu de P. pastoris permet una millor conservació del carboni i un menor malbaratament energètic a través de vies fermentatives. A més, la força del promotor constitutiu pGAP en P. pastoris va provocar que l'activitat específica de MCR fos notablement més alta en comparació amb el promotor pTEF1 en S. cerevisiae (0.30 U/mgproteïna i 0.008 U/mgproteïna, respectivament). Es va realitzar un segon cicle d'enginyeria metabòlica amb l'objectiu d'augmentar el subministrament de malonil-CoA. Es va afegir una segona còpia del gen que codifica el domini C-terminal de MCR (soca PpHP8). La sobreexpressió de la via endògena de producció d'acetil-CoA citosòlic i la supressió de la reacció que produeix el subproducte D-arabitol a la soca PpHP8 va donar lloc a la soca PpHP18. Mentre que la segona còpia del domini C-terminal de MCR (PpHP8) va produir la soca amb un rendiment més alt (0.18 Cmol/Cmol), la soca PpHP18 va mostrar un rendiment de producció inferior (0.15 Cmol/Cmol), mentre que la seva taxa de creixement màxim (µmax) va ser més alta (0.17 h-1 enfront de 0.13 h-1) en cultius a petita escala. Es va portar a terme una anàlisi dels fluxos metabòlic basada en 13C (13C-MFA) utilitzant una plataforma robotitzada d'alt rendiment (High Throughput) per experiments de fluxòmica. Els resultats apunten que el control estricte del flux glicolític en el llevat Crabtree negatiu P. pastoris provoca l'esgotament d'acetil-CoA, donant lloc a limitacions en els recursos per al creixement cel·lular de la soca PpHP8, però rendiments més elevats de 3-HP. Els resultats de 13C-MFA també mostren com els fluxos de la via de la glicòlisi superior i de la via de les pentoses fosfat a la soca PpHP18 es van incrementar molt, cosa que apunta a un malbaratament considerable d'ATP. Això podria explicar el menor rendiment en la producció de 3-HP observat a la soca PpHP18 a la velocitat màxima de creixement. El cultiu en discontinu alimentat (fed-batch) de la soca PpHP8 i PpHP18 van mostrar que la productivitat de la soca PpHP18 va ser notablement superior a la productivitat de la soca PpHP8 (0.71 g/L/h en comparació amb 0.62 g/L/h). La productivitat volumètrica i la concentració final de 3-HP aconseguides són els valors més alts descrits en llevats fins ara.El ácido 3-hidroxipropiónico (3-HP), un producto plataforma, ha sido identificado como uno de los productos de valor añadido más prometedores para ser obtenidos a partir de biomasa por el Departamento de Energía de los Estados Unidos. En consecuencia, en los últimos años, los estudios centrados en la bioproducción de 3-HP han ganado una atención notable. Hasta la fecha, se ha reportado la producción de 3-HP para la revalorización de múltiples fuentes de carbono utilizando varios microorganismos. Esta tesis se enmarca en un proyecto para conseguir producir 3-HP a partir de glicerol en Pichia pastoris (Komagataella phaffii). Esta levadura metilotrófica es capaz de crecer consumiendo el glicerol crudo proveniente de la industria del biodiésel y puede crecer a un pH bajo, facilitando la posterior purificación del 3-HP. La expresión de la vía del malonil-CoA al 3-HP, codificada por el gen de la malonil-CoA reductasa (mcr) de Chloroflexus aurantiacus, en P. pastoris dio lugar a la producción de 3-HP con rendimientos bajos (0.01 Cmol/Cmol, cepa PpHP1). Posteriormente, estrategias de ingeniería enzimática y metabólica dirigidas a aumentar la disponibilidad de cofactores y precursores metabólicos permitieron aumentar 14 veces el rendimiento de producción de 3-HP en comparación con la cepa inicial (0.14 Cmol/Cmol, cepa PpHP6). En concreto, este rendimiento fue ligeramente superior a los descritos anteriormente utilizando otras levaduras que expresaban la misma vía heteróloga, como Saccharomyces cerevisiae o Schyzosaccharomyces pombe (0.12 Cmol/Cmol en ambas levaduras). Esto sugiere que el perfil Crabtree negativo de P. pastoris permite una mejor conservación del carbono y un menor derroche energético a través de vías fermentativas. Además, la fuerza del promotor constitutivo pGAP en P. pastoris provocó que la actividad específica de MCR fuera notablemente más alta en comparación con el promotor pTEF1 en S. cerevisiae (0.30 U/mgproteína y 0.008 U/mgproteína, respectivamente). Se realizó un segundo ciclo de ingeniería metabólica con el objetivo de aumentar el suministro de malonil-CoA. Se añadió una segunda copia del gen que codifica el dominio C-terminal de MCR (cepa PpHP8). La sobrexpresión de la vía endógena de producción de acetil-CoA citosólico y la supresión de la reacción que produce el subproducto D-arabitol en PpHP8 dio lugar a la cepa PpHP18. Mientras que la introducción de la segunda copia del dominio C-terminal de MCR (PpHP8) produjo la cepa con un rendimiento más alto (0.18 Cmol/Cmol), la cepa PpHP18 mostró un rendimiento de producción inferior (0.15 Cmol/Cmol), aunque su tasa de crecimiento máximo (µmax) fue más alta (0.17 h-1 frente a 0.13 h-1) en cultivos a pequeña escala. Se llevó a cabo un análisis de los flujos metabólicos basado en 13C (13C-MFA) utilizando una plataforma robotizada de alto rendimiento (High Throughput) para experimentos de fluxómica. Los resultados apuntan a que el control estricto del flujo glicolítico en la levadura Crabtree negativa P. pastoris provoca el agotamiento de acetil-CoA, dando lugar a limitaciones en los recursos para el crecimiento celular de la cepa PpHP8, pero rendimientos más elevados de 3-HP. Los resultados de 13C-MFA también muestran como los flujos de la vía de la glicólisis superior y de la vía de las pentosas fosfato de la cepa PpHP18 se incrementaron mucho, cosa que apunta a un derroche considerable de ATP. Esto podría explicar el menor rendimiento en la producción de 3-HP observado en PpHP18 a la velocidad máxima de crecimiento. Los cultivos en discontinuo alimentado (fed-batch) de PpHP8 y PpHP18 mostraron que la productividad de la cepa PpHP18 fue notablemente superior a la productividad de PpHP8 (0.71 g/L/h en comparación con 0.62 g/L/h). La productividad volumétrica y la concentración final de 3-HP conseguidas son los valores más altos descritos en levaduras hasta la fecha.3-hydroxypropionic acid (3-HP), a platform chemical, has been identified as one of the top value-added products to be produced from biomass by the US Energy Department. Consequently, 3-HP bioproduction has gained remarkable attention in recent years. So far, production of 3-HP for revalorization of multiple carbon sources has been reported using a variety of microorganisms. In this thesis, the yeast Pichia pastoris (Komagataella phaffii) has been metabolically engineered to produce 3-HP using glycerol as substrate.This methylotrophic yeast is able to grow on crude glycerol from the biodiesel industry and can grow at a low pH, facilitating the downstream processing of 3-HP. Expression of the malonyl-CoA to 3-HP pathway, encoded in the malonyl-CoA reductase gene (mcr) from Chloroflexus aurantiacus in P. pastoris resulted in 3-HP production at low yields on glycerol (0.01 Cmol/Cmol, strain PpHP1). Further enzyme and metabolic engineering approaches aimed at increasing the cofactor and metabolic precursors availability allowed for a 14-fold increase in the production of 3-HP compared to the starting strain (0.14 Cmol/Cmol, strain PpHP6). Notably, this yield was slightly higher to those previously reported using other yeasts with the same heterologous pathway, such as Saccharomyces cerevisiae or Schyzosaccharomyces pombe (0.12 Cmol/Cmol in both yeasts). This suggests that the Crabtree negative profile of P. pastoris allows a better conservation of carbon and a lower energy waste through fermentative pathways. In addition, the strength of the constitutive pGAP promoter in P. pastoris led to a remarkably higher MCR specific activity compared to pTEF1 in S. cerevisiae (0.30 U/mgprotein and 0.008 U/mgprotein, respectively). A second metabolic engineering cycle was performed, aiming at increasing the malonyl-CoA supply. To this end, a second copy of the gene encoding the C-terminal domain of MCR was added (strain PpHP8). In addition, the overexpression of the endogenous cytosolic acetyl-CoA production pathway and the deletion of the reaction producing the by-product D-arabitol in strain PpHP8 yielded the strain PpHP18. While the second copy of the C-terminal domain of MCR (PpHP8) yielded the highest producing strain (0.18 Cmol/Cmol), strain PpHP18 showed a lower production yield (0.15 Cmol/Cmol), while its maximal growth rate (µmax) was higher (0.17 h-1 compared to 0.13 h-1) in small-scale cultivations. To further characterize this series of strains, 13C-based Metabolic Flux Analysis (13C-MFA) was performed using a high throughput fluxomics robotic platform. The results point at the tight control of the glycolytic flux in Crabtree negative yeast P. pastoris causing depletion of acetyl-CoA, resulting in reduced resources for cell growth of strain PpHP8, but higher 3-HP yields. 13C-MFA also shows how the upper glycolysis and pentose phosphate pathway fluxes in strain PpHP18 were highly increased, pointing at a considerable waste of ATP, which might explain the lower 3-HP yield observed in strain PpHP18 at maximal growth rate. Fed-batch cultures of strains PpHP8 and PpHP18 were performed at a pre-programmed constant growth rate of 0.075 h-1. In contrast to the strain rankings observed in small scale cultures, final 3-HP titer obtained for the strain PpHP18 was higher (37.05 g/L, 0.20 Cmol/Cmol) than in PpHP8 (35.4 g/L, 0.18 Cmol/Cmol). Moreover, productivity of strain PpHP18 was remarkably higher than productivity of strain PpHP8 (0.71 g/L/h compared to 0.62 g/L/h), due to the higher growth rate of PpHP18, which led to a shorter batch phase. The volumetric productivity and the final 3-HP concentration achieved herein are the highest values reported in yeast to date, showing the great potential of P. pastoris to produce 3-HP
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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