1,720,955 research outputs found
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
Evaluation of the plastidic antioxidant system in Jatropha curcas and Swietenia macrophylla seedlings submitted to drought stress
Full text linkTropical plants species face a very particular environment with highly variable light intensity, heat, low mineral availability and other abiotic stresses which might have led to the evolution of specific protective mechanisms. The understanding of mechanisms for tolerance over abiotic stress in these plants could help to protect tropical forests, allow a more intelligent grow of economically interesting species and improve crops.
The study of non-model plants, the category for most tropical species, is hindered by the amount of available information and the quality of this data. Swietenia macrophylla has not been sequenced, since the end of this work. To perform an evaluation of gene expression it was necessary to clone previously partial sequences for all required genes and to design specific primers for PCR amplification, including the reference genes. This work was supported by phylogenetic analysis, nourished by available sequences of related species. On the contrary, Jatropha curcas is on its way to becoming a novel model-species for genetic and eco-physiological studies. The species was sequenced in 2010 and had already some studies of gene expression under abiotic stress. Even when it is a helpful aspect to be able to compare results with other studies, it was demonstrated here that the provided information still needs to be carefully evaluated before it is used. The validity of the information for 2CP, APX, GPX and CAT obtained in two different databases, was corroborated by cloning full cDNA sequences. The characterization of genes belonging to the enzymatic antioxidant system in chloroplasts was performed by studies of exon and for 2CP and APX, the chloroplast targeting was confirmed by transient transformation of N. benthamiana with a construct carrying the signal peptide and a reporter gene.
Stress experiments were performed in outdoor conditions in Panama for Swietenia, and also in greenhouse conditions in Berlin, for Jatropha; they included mainly variations in temperature and irradiance. Physiological parameters such as stem elongation, leaf area, and biomass production seemed different between the two species, praising Jatropha for its capacity of growth regulation during mild and severe drought stress. Nevertheless, PSII quantum yield and CO2 assimilation rates in Swietenia unveiled an unexpected photosynthetic capacity during drought.
The gene regulation of the antioxidant enzymes in Swietenia proved, in most cases, to be similar to the description for other C3 drought sensitive plants such as Arabidopsis. Though few times reached statistical significance, there was considered that plants under treatment experienced a trend for up-regulation in 2CP, APX and GPX during mild stress, for down-regulation during severe stress, and after re-watering, all three genes came back to regular expression. In the case of Jatropha, there was not one single trend for each gene. During mild stress, 2CP was not regulated and APX was down-regulated. During severe stress and re-watering, there was reported a pattern of expression for each gene, depending on the growth conditions of each experimental setup. Moreover, CAT was inhibited by low light intensities in Jatropha at all phases of the experiment and was not upregulated during mild or severe stress inadequate light intensities.
Based on the final holistic evaluation, it can be confirmed that the regulation mechanism of the antioxidant system in the chloroplasts is more sensitive in Jatropha. Counting only the genes evaluated in both species, there was a fine-tuning regulation in the antioxidant system of Jatropha that was not observed in Swietenia. Jatropha curcas can be considered as more tolerant to drought because it can adjust gene transcription levels more specifically, presenting various regulation patterns for each gene and in all evaluated drought conditions, in a balanced way.Tropische Pflanzenarten sind einer sehr spezifischen Umgebung mit stark schwankender Lichtintensität, Wärme, geringer Mineralverfügbarkeit und anderen abiotischen Stressfaktoren ausgesetzt, die zur Entwicklung spezifischer Schutzmechanismen geführt haben könnten. Das Verständnis von Mechanismen der abiotischen Stresstoleranz könnte helfen, tropische Wälder zu schützen, ein intelligenteres Wachstum von wirtschaftlich interessanten Arten zu ermöglichen und Nutzpflanzen zu verbessern.
Die Untersuchung von Nichtmodellpflanzen, der Kategorie für die meisten tropischen Arten, wird durch die geringe Anzahl an verfügbaren Informationen und die Qualität dieser Daten behindert. Swietenia macrophylla ist bis zum Ende dieser Arbeit nicht sequenziert. Um eine Evaluierung der Genexpression durchzuführen, war es notwendig, zuvor Teilsequenzen für alle erforderlichen Gene zu klonieren und spezifische Primer für die PCR-Amplifikation, einschließlich der Referenzgene, zu entwerfen. Diese Arbeit wurde durch eine phylogenetische Analyse gestützt, genährt von verfügbaren Sequenzen verwandter Arten. Im Gegenteil ist Jatropha curcas auf dem Weg eine neue Modellspezies für genetische und ökophysiologische Studien zu werden. Die Art wurde 2010 sequenziert und es gibt bereits einige Studien zur Genexpression unter abiotischem Stress. Auch wenn es ein hilfreicher Aspekt ist, Ergebnisse mit anderen Studien vergleichen zu können, wurde hier gezeigt, dass die bereitgestellten Informationen noch sorgfältig ausgewertet werden müssen, bevor sie verwendet werden. Die Gültigkeit der Information für 2CP, APX, GPX und Catalase in zwei Datenbanken wurde durch Klonen vollständiger Sequenzen bestätigt. Die Gencharakterisierung für das enzymatische Antioxidationssystem in Chloroplasten wurde durch Exonstudien durchgeführt, und für 2CP und APX wurde das Targeting der Chloroplasten durch transiente Transformation von N. benthamiana mit einem Konstrukt, das das Signalpeptid und ein Reportergen trägt, bestätigt.
Stressexperimente wurden unter Freilandbedingungen in Panama für Swietenia und auch in Gewächshausbedingungen in Berlin für Jatropha durchgeführt; Sie beinhalteten hauptsächlich Schwankungen in Temperatur und Bestrahlungsstärke. Physiologische Parameter wie Stammlänge, Blattfläche und Biomasseproduktion sind zwischen den beiden Arten unterschiedlich und zeigen, dass Jatropha die Fähigkeit besitzt das Wachstums während unter leichten und schweren Trockenstress zu regulieren. Dennoch zeigten die PSII-Quantenausbeute und die CO2-Assimilationsraten in Swietenia eine unerwartete photosynthetische Kapazität während der Dürre.
Die Genregulation der antioxidativen Enzyme in Swietenia erwies sich in den meisten Fällen als ähnlich zu der Beschreibung für andere C3 dürreempfindliche Pflanzen wie Arabidopsis. Obwohl kaum signifikant, wurde ein Trend für 2CP, APX und GPX für die Hochregulation bei leichtem Stress, für die Runterregulation während des schweren Stresses und nach dem erneuten Gießen erkannt. Im Falle von Jatropha gab es kein Trend in der Genexpression. Bei leichter Belastung war 2CP nicht reguliert und APX wurde herunterreguliert. Während starker Belastung und erneuter Bewässerung wurde ein Expressionsmuster für jedes Gen beobachtet, abhängig von den Wachstumsbedingungen jeder Versuchsanordnung. Darüber hinaus wurde CAT in allen Phasen des Experiments durch niedrige Lichtintensitäten in Jatropha gehemmt beobachtet und wurde während leichter oder starker Belastung nicht hochreguliert.
Basierend auf der abschließenden ganzheitlichen Bewertung kann bestätigt werden, dass der Regulationsmechanismus des antioxidativen Systems in den Chloroplasten in Jatropha empfindlicher ist. Betrachtet man nur die bei beiden Spezies untersuchten Gene, so gab es eine Feinregulierung im antioxidativen System von Jatropha, die in Swietenia nicht beobachtet wurde. Jatropha kann als toleranter gegenüber Trockenheit angesehen werden, da sie die Genexpression spezifischer anpassen kann, indem sie verschiedene Regulationsmuster in allen Genen und unter allen Dürrebedingungen in ausgewogener Weise präsentiert.Las plantas tropicales se enfrentan a un entorno muy particular con altas variaciones en intensidad de luz y temperatura, poca disponibilidad de minerales y otros tipos de stress abiótico que podrían haber llevado a la evolución de mecanismos específicos de protección. La comprensión de los mecanismos de tolerancia en estas plantas podría ayudar a proteger los bosques tropicales, permitir un crecimiento más inteligente de especies económicamente interesantes y mejorar los cultivos.
El estudio de plantas no-modelo, la categoría en la que se incluyen la mayoría de las especies tropicales, se ve obstaculizada por la cantidad de información disponible y la calidad de estos datos. Swietenia macrophylla no ha sido secuenciada hasta la culminación de este trabajo. Para realizar una evaluación de la expresión génica fue necesario clonar previamente secuencias parciales para todos los genes requeridos y diseñar cebadores (primers) específicos para la amplificación por PCR, incluidos los genes de referencia. Este trabajo fue respaldado por análisis filogenéticos y nutridos con las secuencias disponibles de especies relacionadas. Por el contrario, Jatropha curcas está en camino de convertirse en una nueva especie modelo para estudios genéticos y eco-fisiológicos. La especie fue secuenciada en 2010 y ya cuenta con algunos estudios de regulación génica bajo estrés abiótico. Incluso cuando es beneficioso poder comparar los resultados con otros estudios, aquí se demostró que la información provista debe ser cuidadosamente evaluada antes de ser utilizada. La validez de la información para 2CP, APX, GPX y CAT obtenida de dos bases de datos diferentes se corroboró clonando secuencias completas de cDNA. La caracterización de los genes pertenecientes al sistema antioxidante enzimático en los cloroplastos se realizó mediante estudios de exones; además, se confirmó la localización en el cloroplasto de 2CP y APX por transformación transitoria de N. benthamiana con un plásmido que portaba el pre-péptido marcador de localización y un marcador fluorescente.
Los experimentos de sequía se realizaron en condiciones al aire libre en Panamá para Swietenia, y también en condiciones de invernadero en Berlín, para Jatropha; incluyendo principalmente variaciones de temperatura e irradiación. Parámetros fisiológicos como el alargamiento del tallo, el área foliar y la producción de biomasa son diferentes entre las dos especies, distinguiendo a Jatropha por su capacidad de regulación del crecimiento durante periodo de sequía leve y grave. Sin embargo, el rendimiento cuántico del PSII y las tasas de asimilación de CO2 en Swietenia revelaron una capacidad fotosintética inesperadamente alta durante la sequía también.
La regulación génica de las enzimas antioxidantes en Swietenia demostró, en la mayoría de los casos, ser similar a la descripción de otras plantas sensibles a la sequía C3, como Arabidopsis. Aunque pocas veces alcanzó niveles de significancia estadística, se consideró que las plantas bajo tratamiento experimentaron una tendencia de regulación al incremento para 2CP, APX y GPX durante periodos de estrés leves; de regulación en reducción en los tres genes bajo estrés severo, y después de volver a regar, estos tres genes regresaron a la expresión regular. En el caso de Jatropha, no hubo una sola tendencia para cada gen. Durante estrés leve, 2CP no fue regulado y APX fue regulado negativamente. Durante estrés severo y recuperación, se observaron varios patrones de expresión para cada gen, dependiendo de las condiciones de crecimiento de cada experimento. Además, se observó que CAT se inhibía por la baja intensidad de la luz en Jatropha en todas las fases del experimento y no se regulaba positivamente durante el estrés leve o severo en condiciones lumínicas adecuadas.
Basado en la evaluación holística final, se puede confirmar que el mecanismo de regulación del sistema antioxidante en los cloroplastos es más sensible en Jatropha. Considerando solo los genes evaluados en ambas especies, hubo una delicada regulación del sistema antioxidante de Jatropha que no se observó en Swietenia. Jatropha curcas se puede considerar como más tolerante a la sequía porque puede ajustar los niveles de transcripción de los genes más específicamente, presentando varios patrones de regulación en cada uno los genes y en todas las condiciones de sequía evaluadas, de una manera equilibrada
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
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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