1,720,959 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
A quantitative study of myocardial motion and deformation during early mouse morphogenesis
No full textLa morfogénesis del corazón es un proceso fascinante en el que unas pocas células se transforman en un órgano de bombeo plenamente funcional. Este proceso complejo implica varias etapas de desarrollo, durante las cuales las células se multiplican y reorganizan, dando forma gradualmente al corazón. Estos cambios implican modificaciones en la expresión de genes, aspectos bioquímicos y morfológicos que interactúan de manera organizada en diferentes escalas de tiempo y espacio. Aunque la cardiogénesis ocurre de manera robusta y reproducible, durante el desarrollo embrionario, la forma del corazón puede variar entre especímenes.
Gracias a los avances recientes en la física de la microscopía y al desarrollo de proteínas fluorescentes que indican los patrones espaciales de expresión génica, ahora podemos observar el desarrollo del corazón en vivo. Esta técnica de imágenes nos proporciona datos tridimensionales de alta resolución en diferentes momentos, ofreciendo una representación digital de la morfología del corazón. Sin embargo, estos datos requieren técnicas novedosas de procesamiento y análisis de imágenes para extraer información relevante.
La cuantificación de la deformación y la dinámica involucradas en el proceso de formación del corazón es uno de los desafíos más relevantes en el campo de la biología del desarrollo. Sin embargo, debido a la complejidad del proceso y a las limitaciones para obtener imágenes en vivo del desarrollo cardiaco con suficiente penetración en el tejido y a lo largo de todo el proceso, existe un vacío de conocimiento sobre la deformación subyacente del tejido cardiaco durante la morfogénesis temprana. Esta tesis doctoral aborda este desafío proponiendo una metodología sistemática para cuantificar y comparar los patrones de deformación tisular, utilizando perfiles de movimiento estimados a partir de múltiples imágenes de microscopía fluorescente 3D en vivo. La metodología propuesta se centra en la cuantificación de la cinemática del movimiento, específicamente la deformación y las tensiones, sin tener en cuenta las fuerzas que causan dicho movimiento. Esto se logra mediante un análisis no invasivo directamente en las imágenes en vivo individuales. Para alinear los perfiles de movimiento de diferentes especímenes a lo largo del tiempo, la metodología incorpora un sistema de estadificación que sincroniza las imágenes dinámicas con un modelo geométrico pseudodinámico previamente descrito de la morfología del tejido cardiaco durante la morfogénesis [1]. Para validar este enfoque, se compararon los movimientos celulares rastreados manualmente con los rastreos predichos por el modelo implementado. Los resultados obtenidos validaron esta estrategia para describir las trayectorias celulares y la deformación tisular a nivel celular.
Para abordar la variabilidad en la forma del corazón y facilitar la comparación de los patrones de deformación, la metodología incluye un proceso de registro que proyecta cada espécimen individual sobre la forma sincrónica del modelo geométrico, que sirve como referencia espacial. El modelo generado proporciona un perfil temporal de la deformación durante las diferentes etapas de desarrollo, incluyendo eventos instantáneos y la historia acumulada de la deformación. Estos mapas también permiten el análisis computacional de los destinos celulares o regionales. Los resultados obtenidos indican una marcada compartimentación de la expansión y compresión tisular, así como de la anisotropía de la deformación. Por lo tanto, aunque los cardiomiocitos en el primordio cardiaco temprano parecen homogéneos, en realidad muestran un comportamiento altamente heterogéneo regulado regionalmente.
En resumen, esta tesis doctoral presenta un marco metodológico exhaustivo para el análisis cuantitativo y la comparación de la deformación tisular en corazones en desarrollo. Los resultados de este estudio revelan una notoria compartimentación del tejido cardiaco, que incluye zonas diferenciadas de anisotropía y expansión. Gracias al uso de esta metodología, es posible identificar y seguir los cambios morfológicos en el tejido cardiaco en desarrollo, lo que permite inferir la dinámica de las células cardiacas durante el proceso de desarrollo. Esta caracterización proporciona una base crucial para el desarrollo de modelos mecánicos y, lo que es más importante, ofrece una comprensión más profunda de la complejidad del desarrollo del corazón.
ABSTRACT
Heart morphogenesis is a fascinating process wherein a few cells undergo transformation to form a fully functioning pumping organ. This intricate process spans multiple development stages, during which the cell population proliferates and rearranges gradually shaping the heart. This complexity arises from genetic, biochemical, and morphological changes that interact in a highly organized manner across different spatio-temporal scales. Despite cardiogenesis occurs in a robust and reproducible way, it gives rise to a variable heart shape when comparing different specimens.
Recent advances in microscopy physics and the development of fluorescent proteins capable of reporting spatial gene expression patterns, have enabled in vivo observation of heart development. This imaging process generates high spatio-temporal resolution 3D+t data, providing a digital representation of heart morphogenesis. However, extracting information from these data necessitates novel image processing and data analysis techniques.
Quantifying the deformation and dynamics involved in heart shaping is a significant and challenging area of developmental biology. However, due to the complexity of the process and the limitations in live imaging with sufficient tissue penetration and coverage throughout the entire process, there is a knowledge gap concerning the underlying heart tissue deformation during early morphogenesis. This PhD thesis addresses this challenge by proposing a systematic methodology to quantify and compare tissue deformation patterns, integrating motion profiles estimated from multiple 3D live fluorescent microscopy images. The proposed framework focuses on quantifying motion kinematics, specifically deformation and strains, without considering the forces causing such motion. This is achieved through a non-invasive analysis made directly on individual live images. To align the individual motion profiles of multiple specimens over time, the framework incorporates a staging system that synchronizes 3D live images with a previously described pseudodynamic ATLAS of tissue geometry during heart morphogenesis [1]. To validate this approach, we compared tracked cell motions with tracks predicted by the implemented method. The obtained results validated this strategy for description of cell trajectories and tissue deformation at cellular level.
To address the issue of heart shape variability and facilitate comparison of deformation patterns, the framework includes a registration process that projects each individual specimen onto the synchronous ATLAS shape, which serves as a spatial reference. This framework maps the temporal profile of deformation during different developmental stages, including both instantaneous events and cumulative deformation history. The generated maps also enable in silico fate map analysis at the cellular or regional level. The results indicate a sharp compartmentalization of tissue expansion/compression and deformation anisotropy. Therefore, although cardiomyocytes of the early cardiac primordium appear homogeneous, in fact they show a highly heterogeneous behaviour that is regionally regulated.
In summary, this PhD thesis presents a comprehensive framework for the quantitative analysis and comparison of tissue deformation in developing hearts. The study’s results reveal a remarkable compartmentalization of heart tissue, including distinct zones of anisotropy and expansion. Through the use of this framework, it becomes possible to identify and track morphological changes in developing heart tissue, providing inferred insights into the dynamics of heart cells during the development process. This characterization establishes a crucial foundation for the development of mechanical models and, more importantly, offers a deeper understanding of the intricate complexity of heart development
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
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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