1,720,995 research outputs found
Evaluation of the electrothermal effects of low-frequency electromagnetic fields on human limb-associated tissue
No full textilustraciones, diagramas, tablasDada la naturaleza de su funcionamiento, la infraestructura de transmisión y distribución de energía eléctrica genera campos electromagnéticos en el ambiente, los cuales pueden generar efectos biológicos que van desde la percepción hasta la molestia [1]. Ahora bien, el límite del nivel de exposición a estos campos no es un estándar internacional; en su lugar, cada país se encarga de establecer sus límites de exposición. Asimismo existe literatura que permite aproximarse a los efectos de la exposición a campos electromagnéticos de baja frecuencia en el cuerpo humano. Con esta información, es posible evaluar los valores límite de exposición según la población de cada país, incluso en ausencia de un estándar establecido para este propósito.
La presente investigación parte de una revisión de la bibliografía sobre los efectos de la radiación no ionizante en tejidos biológicos. Esta proporciona las bases para el desarrollo de modelos computacionales de extremidades para la evaluación de dosimetría a baja frecuencia. Los modelos usan geometrías simples como círculos (2D) y cilindros (3D), los cuales contemplan diferentes capas de tejidos con sus respectivos parámetros eléctricos. Posteriormente, estos datos se complementan con los parámetros térmicos con el objetivo de aproximar los efectos electrotérmicos ocasionados por la radiación no ionizante a 60 Hz. Los resultados muestran cómo la orientación, el tamaño, los parámetros eléctricos de los tejidos y las condiciones de frontera de las extremidades influyen en los campos eléctricos internos distribuidos o inducidos. Por último, se estimaron los efectos eléctricos de densidad de corriente, campo eléctrico interno y densidad de flujo magnético para diferentes niveles de exposición, los cuales aproximan variaciones de temperatura entre 10^{-9} °C y 10^{-5} °C en tejidos como la piel.
El estudio concluye con la propuesta de un modelo computacional basado en extremidades del cuerpo humano que aproxima los efectos eléctricos generados por la exposición a campos electromagnéticos de 60 Hz, permitiendo estimar densidades volumétricas de energía y aumentos de temperatura. Finalmente, se proponen recomendaciones enfocadas al ajuste de los valores normativos colombianos y a la elección de parámetros eléctricos de los tejidos para el desarrollo de modelos computacionales de dosimetría a baja frecuencia (Texto tomado de la fuente)Given the nature of its operation, the electric power transmission and distribution infrastructure generates electromagnetic fields in the environment, which can generate biological effects ranging from perception to annoyance [1]. However, the exposure level limit to these fields is not an international standard; each country is responsible for setting its exposure limits. There is also literature that makes it possible to approximate the effects of exposure to low-frequency electromagnetic fields on the human body. With this information, it is possible to evaluate the exposure limit values according to the population of each country, even in the absence of an established standard for this purpose.
The present research is based on a literature review of the effects of non-ionizing radiation on biological tissues. It provides the basis for the development of computational models of extremities for the evaluation of low-frequency dosimetry. The models use simple geometries such as circles (2D) and cylinders (3D), which contemplate different tissue layers with their respective electrical parameters. Subsequently, these data are complemented with thermal parameters to approximate the electrothermal effects caused by non-ionizing radiation at 60 Hz. The results show how the orientation, size, electrical parameters of the tissues, and boundary conditions of the limbs influence the distributed or induced internal electric fields. Finally, electrical effects of current density, internal electric field, and magnetic flux density were estimated for different exposure levels, which approximate temperature variations between 10^{-9} °C and 10^{-5} °C in tissues such as skin.
The study concludes with the proposal of a computational model based on human body extremities that approximates the electrical effects generated by exposure to 60 Hz electromagnetic fields, allowing the estimation of volumetric energy densities and temperature increases. Finally, recommendations focused on the adjustment of Colombian normative values and the choice of electrical parameters of tissues for developing computational models of low-frequency dosimetry are proposed.MaestríaMagíster en Ingeniería - Ingeniería EléctricaDesarrollo y evaluación de modelos computacionales 2D y 3D en el ámbito del electromagnetismo y su interacción con el cuerpo humano.Energía y electromagnetism
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
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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