1,721,159 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
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
Developing non-animal methods for thyroid toxicity testing – Validation of a novel in vitro assay investigating Deiodinase I inhibition
Full text linkThe human body can be targeted by many man-made and natural-occurring chemicals, potentially leading to adverse effects. This includes the endocrine system, essentially consisting of the EATS modalities (estrogen, androgen, thyroid, and steroidogenesis). Substances that interfere with the endocrine systems are called endocrine active substances and can finally be assessed as endocrine disruptors. Endocrine disruptors cannot be registered in the EU, unless exposure to the environment is negligible.
The thyroid hormone system (THS) is important in regulating various physiological processes, including metabolism, energy regulation, and organ function. The THS controls gene expression and pathways that impact metabolism, thermoregulation, cardiovascular function, and neural connectivity. Perturbations in the THS can lead to increased or decreased thyroid hormone (TH) signalling as well as thyroid-related diseases including cancer. The developing foetus is dependent on maternal TH supplementation, and very susceptible towards alterations in TH supply. Resulting developmental changes are also called developmental neurotoxicity.
Testing for THS parameters is routinely done in animal experiments. The EU wants to accelerate the switch from animal to non-animal methods (NAMs). Currently, there is no OECD validated NAM for the THS available. Newly developed NAMs should be standardized and reproducible. They should adhere to the Guidance Document on Good In Vitro Method Practices (GIVIMP) that provides guidance on critical aspects for the development of reliable and reproducible in vitro methods.
The THS is a complex signalling pathway that includes production, secretion, transport, uptake, signalling and metabolization of TH as well as a negative feedback loop to control TH release. The iodothyronine deiodinases (DIO) are one important key event (KE) in the THS and is linked to adverse neurodevelopmental outcomes in mammals. DIOs regulate TH signalling by metabolizing TH to more or less active TH metabolites.
Historically, testing for DIO1 inhibition was done in animals. A novel in vitro method using mouse liver enzyme as a source for DIO1 and the Sandell-Kolthoff (SK) reaction to quantify released iodide from a substrate was published in 2014. This method is part of a validation study led by the European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) with the goal to develop NAMs that cover different endpoints in the THS. The validation consists of two parts where the reproducibility of the method is demonstrated (part 1) and the method is checked for its relevance and reliability (part 2).
In this work, the DIO1-SK assay was optimized and standardized. Mouse liver microsomes were substituted by human liver microsomes to adhere to the human situation. Variability of generated results was reduced by implementing measures to control batch-specific microsome activity, inherent activity of assay constituents in the SK reaction and optimal enzymatic iodide release during microsome incubation. Linear reaction kinetics in the SK reaction was ensured by optimizing incubation time and variable SK reagent concentrations. The reproducibility of the DIO1-SK assay was demonstrated by testing of six described DIO1 inhibitors in at least five independent assay runs (part 1). Guidance for establishing the method at other laboratories was provided; an initial Standard Operation Procedure (SOP) as well as acceptance criteria to assess the validity of future runs were defined.
Using the derived SOP, the DIO1-SK assay was tested for its predictivity using a described class of DIO inhibitors, gold-containing substances. As such, organic, inorganic gold substances as well as gold nanoparticles were tested. A strategic approach using the mentioned gold substances as well as substances lacking the gold moiety was chosen to verify that the observed DIO1-inhibition was mediated by the gold. All tested organic and inorganic gold substances produced DIO1 inhibition at concentrations comparable to the literature. Structural analogues lacking the gold moiety did not produce DIO1 inhibition. Interestingly, small gold nanoparticles (5 nm) caused DIO1 inhibition, while bigger nanoparticles (>30 nm) did not. It was verified that the observed inhibition was not caused by dissolved gold in the incubation media. This study verified the potential of the DIO1-SK assay to predict DIO1 inhibition and has shown the applicability of the method towards nanoparticles.
For the part 2 of the validation study of EURL ECVAM, the predictivity of the assay was assessed. A blinded set of substances, provided by the EU, was tested in the method. This included thorough solubility testing as well as two newly introduced methods to assess the specificity of observed DIO1 inhibition. Upon experimental completion, the data was deblinded and compared to available literature data. A data interpretation procedure (DIP) using the variability of the assay was used to categorize the results. Multiple substances produced high inhibition. The introduced specificity methods identified two substances as method-interfering leading to exclusion for further analysis. Inhibition data was consistent with available in vitro and in silico literature data showing the methods relevance. A DIP was derived using three categories classifying substance into full, partial or no inhibitor based on efficacy. Additionally, full inhibitors were subcategorized into potent and weak full inhibitors using the substances IC50 (“potency”). An updated SOP was derived and published to allow other laboratories to use the method.
In this thesis, an in vitro method was developed that predicts the KE of DIO1 inhibition optimized, standardized, and reproducibly. It includes methods to exclude undissolved substance, observed effects that are not specific to inhibition of DIO1 and a method-specific DIP that classifies the generated data based on assay-inherent variability. The work presented is the basis for the acceptance of the method at OECD level and is a forerunner in the validation study coordinated by EURL ECVAM. Once methods covering other KEs in the THS are validated, they must be combined with the DIO1-SK assay to form an in vitro test battery. This includes computational methods that can predict different KEs and modelling that extrapolates enzymatic data to an organismal level. The current acceptance process for methods on an OECD level takes multiple years. Acceptance processes for NAMs at the OECD must be accelerated to make validated methods available more quickly and further drive the switch from animal to non-animal testing.Viele menschengemachte und natürlich vorkommende Chemikalien können auf den menschlichen Körper einwirken und möglicherweise schädliche Effekte haben. Dazu gehört das endokrine System, das im Wesentlichen aus den EATS-Modalitäten (Östrogen, Androgen, Schilddrüse und Steroide) besteht. Stoffe, die in das endokrine System eingreifen, werden als endokrin aktive Stoffe bezeichnet und können letztlich als endokrine Disruptoren eingestuft werden. Endokrine Disruptoren können in der EU nicht registriert werden, es sei denn, die Exposition gegenüber der Umwelt ist vernachlässigbar.
Das Schilddrüsenhormonsystem (THS) ist wichtig für die Regulierung verschiedener physiologischer Prozesse, einschließlich Stoffwechsel, Energieregulierung und Organfunktion. Das THS steuert die Genexpression und Signalwege, die den Stoffwechsel, die Thermoregulation, die Herz-Kreislauf-Funktion und die neuronale Konnektivität beeinflussen. Störungen im THS können zu einer erhöhten oder verminderten Schilddrüsenhormon (TH)-Signalübertragung sowie zu Schilddrüsenerkrankungen, einschließlich Krebs, führen. Der sich entwickelnde Fötus ist besonders auf die mütterliche TH-Ergänzung angewiesen und daher anfällig für Veränderungen in der TH-Versorgung. Daraus resultierende Entwicklungsveränderungen werden auch als Entwicklungsneurotoxizität bezeichnet.
Die Prüfung der THS-Parameter erfolgt routinemäßig in Tierversuchen. Die EU will die Umstellung von tierischen zu tierversuchsfreien Methoden(NAMs) genannt, beschleunigen. Derzeit ist keine von der OECD validiertes NAM für das THS verfügbar. Neu entwickelte NAMs sollten standardisiert und reproduzierbar sein. Sie sollten sich an dem Guidance Document on Good In Vitro Method Practices (GIVIMP) orientieren, das Leitlinien zu kritischen Aspekten der Entwicklung zuverlässiger und reproduzierbarer in-vitro Methoden bietet.
Das THS ist ein komplexer Signalweg, der Produktion, Sekretion, Transport, Aufnahme, Signalübertragung und Metabolisierung des TH sowie eine negative Rückkopplungsschleife zur Steuerung der TH-Freisetzung umfasst. Die Iodothyronin-Deiodasen (DIO) sind ein wichtiges Schlüsselereignis (KE) im THS und werden mit negativen Folgen für die neurologische Entwicklung bei Säugetieren in Verbindung gebracht. DIOs regulieren die TH-Signalübertragung, indem sie TH zu mehr oder weniger aktiven TH-Metaboliten metabolisieren.
In der Vergangenheit wurden Tests zur DIO1-Inhibition an Tieren durchgeführt. Im Jahr 2014 wurde eine neuartige in-vitro Methode veröffentlicht, die Mausleberenzym als Quelle für DIO1 und die Sandell-Kolthoff (SK)-Reaktion nutzt, um freigesetztes Iodid aus einem Substrat zu quantifizieren. Diese Methode ist Teil einer Validierungsstudie unter der Leitung des Referenzlabors der Europäischen Union für Alternativen zu Tierversuchen (EURL ECVAM) mit dem Ziel NAMs zu entwickeln, die verschiedenen Endpunkte im THS abdecken. Die Validierung besteht aus zwei Teilen, in denen die Reproduzierbarkeit der Methode nachgewiesen wird (Teil 1) und die Methode auf ihre Relevanz und Zuverlässigkeit überprüft wird (Teil 2).
In dieser Arbeit wurde der DIO1-SK-Assay optimiert und standardisiert. Mauslebermikrosomen wurden durch menschliche Lebermikrosomen ersetzt, um der menschlichen Situation zu entsprechen. Die Variabilität der generierten Ergebnisse wurde durch die Implementierung von Maßnahmen zur Kontrolle der chargenspezifischen Mikrosomenaktivität, der inhärenten Aktivität der Testbestandteile in der SK-Reaktion und der optimalen enzymatischen Iodidfreisetzung während der Mikrosomeninkubation verringert. Die lineare Reaktionskinetik der SK-Reaktion wurde durch die Optimierung der Inkubationszeit und variabler SK-Reagenzienkonzentrationen sichergestellt. Die Reproduzierbarkeit des DIO1-SK-Assays wurde durch das Testen von sechs beschriebenen DIO1-Inhibitoren in mindestens fünf unabhängigen Wiederholungen nachgewiesen (Teil 1). Es wurden Informationen zur Etablierung der Methode in anderen Laboratorien bereitgestellt. Eine initiale Standardarbeitsanweisung (SOP) sowie Akzeptanzkriterien zur Beurteilung der Gültigkeit zukünftiger Läufe definiert.
Unter Verwendung der abgeleiteten SOP wurde der DIO1-SK-Assay auf seine Vorhersagekraft unter Verwendung einer beschriebenen Klasse von DIO-Inhibitoren, goldhaltigen Substanzen, getestet. Dabei wurden sowohl organische, anorganische Goldsubstanzen als auch Goldnanopartikel getestet. Um zu verifizieren, dass die beobachtete DIO1-Hemmung durch das Gold vermittelt wurde, wurde ein strategischer Ansatz gewählt, bei dem die genannten Goldsubstanzen sowie Substanzen ohne Goldanteil verwendet wurden. Alle getesteten organischen und anorganischen Goldsubstanzen führten verglichen zu Literaturdaten zur kompletten DIO1-Inhibition bei vergleichbaren Konzentrationen. Strukturanaloge ohne Goldanteil führten nicht zu einer DIO1-Hemmung. Interessanterweise verursachten kleine Goldnanopartikel (5 nm) zu einer DIO1-Hemmung, größere Nanopartikel (>30 nm) hingegen nicht. Es wurde sichergestellt, dass die beobachtete Hemmung nicht durch gelöstes Gold in den Inkubationsmedien verursacht wurde. Diese Studie bestätigte das Potenzial des DIO1-SK-Assays zur Vorhersage der DIO1-Inhibition und zeigte die Anwendbarkeit der Methode auch auf Nanopartikel.
Für Teil 2 der Validierungsstudie von EURL ECVAM wurde die Vorhersagekraft des Assays bewertet. In der Methode wurden von der EU bereitgestellte, verblindete Substanzen getestet. Dazu gehörten gründliche Löslichkeitstests sowie zwei neu eingeführte Methoden zur Beurteilung der Spezifität der beobachteten DIO1-Inhibition. Nach Abschluss des Experiments wurden die Daten entblindet und mit verfügbaren Literaturdaten verglichen. Zur Kategorisierung der Ergebnisse wurde ein Dateninterpretationsverfahren (DIP) verwendet, das die Variabilität des Assays nutzte. Mehrere Substanzen führten zu einer starken Hemmung von DIO1. Die eingeführten Spezifitätsmethoden identifizierten zwei Substanzen als interferierend, was zum Ausschluss für die weitere Analyse führte. Die Inhibitionsdaten stimmten mit den verfügbaren in-vitro und in-silico Literaturdaten überein und zeigen die Relevanz der Methode. Ein DIP wurde mithilfe von drei Kategorien abgeleitet, die die Substanz basierend auf ihrer Wirksamkeit in vollständige, teilweise oder Nicht-Inhibitoren einteilten. Zusätzlich wurden vollständige Inhibitoren anhand der IC50 der Substanz („Potenz“) in potente und schwache, vollständige Inhibitoren unterteilt. Eine aktualisierte SOP wurde erstellt und veröffentlicht, um anderen Laboren die Nutzung der Methode zu ermöglichen.
In dieser Arbeit wurde eine in-vitro Methode entwickelt, die das KE der DIO1-Hemmung optimiert, standardisiert und reproduzierbar vorhersagen kann. Es umfasst Methoden zum Ausschluss des Testens von ungelösten Substanzen, beobachtete Effekte, die nicht spezifisch für die Hemmung von DIO1 sind, und einen methodenspezifischen DIP, der die generierten Daten basierend auf der testinhärenten Variabilität klassifiziert. Die vorgestellte Arbeit bildet die Grundlage für die Akzeptanz der Methode auf OECD-Ebene und ist Vorreiter der von EURL ECVAM koordinierten Validierungsstudie. Sobald Methoden validiert sind, die andere KEs im THS abdecken, müssen sie mit dem DIO1-SK-Assay kombiniert werden, um eine in-vitro Testbatterie zu bilden. Dazu gehören computerbasierte Methoden, die verschiedene KEs vorhersagen können, und Modellierungen, die die enzymatischen Daten auf die Ebene des Organismus extrapolieren können. Der aktuelle Akzeptanzprozess für Methoden auf OECD-Ebene ist langwierig und dauert mehrere Jahre. Die Akzeptanzprozesse für NAMs bei der OECD müssen beschleunigt werden, um validierte Methoden schneller verfügbar zu machen und die Umstellung der Toxizitätstestung mit Tierversuchen auf tierversuchsfreie Tests weiter voranzutreiben
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
- …
