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Relief of exertional breathlessness following bariatric surgery for severe obesity: Physiological mechanisms
No full textPurpose: Obese adults are two-to-four times more likely to experience physical activity-limiting breathlessness than their normal weight counterparts. Despite the high prevalence of breathlessness in obesity, researchers and healthcare providers have a limited understanding of the physiological mechanisms of breathlessness on exertion in obesity. Therefore, the aim of this study was to advance the understanding of the physiological mechanisms of exertional breathlessness in obesity by examining the effects of extreme weight loss through bariatric surgery for class III obesity (BMI>40 kg/m2) on physiological and breathlessness responses during cardiopulmonary cycle exercise testing. We hypothesized that relief of exertional breathlessness following bariatric surgery would be primarily related to the reduced metabolic and ventilatory requirements of exercise, while changes in static and dynamic respiratory mechanics would be less important.Methods: We compared cardiac, metabolic, ventilatory, breathing pattern, operating lung volume and breathlessness responses to symptom-limited incremental CPET (25-watts/2-min) in 6 obese adults (3 women) aged 43.7±2.8 years (mean±SEM) before (PRE) and 3-months after bariatric surgery (POST). Pulmonary function test and body composition parameters were also compared PRE and POST.Results: Compared with PRE, body mass, BMI, fat mass and lean body mass decreased by an average of 23.8 kg (129.4±6.2 vs.105.6±5.8 kg), 8.7 kg/m2 (47.1±1.6 vs. 38.4±1.6 kg/m2), 18.5 kg (61.6±4.6 vs. 43.1±4.8 kg) and 4.4 kg (62.2±4.1 vs. 57.8±4.6 kg) in POST, respectively (all p<0.05). Peak power output was not significantly different in POST vs. PRE: 154±21 vs. 133±11 watts (p=0.185). With few exceptions, heart rate, the rate of oxygen uptake, the rate of carbon dioxide production and minute ventilation (V̇E) were lower during exercise in POST vs. PRE. The reduced V̇E response to exercise in POST vs. PRE reflected adoption of a relatively slower (less tachypneic) breathing pattern. Inspiratory capacity (IC) decreased by 0.13 L from rest-to-peak exercise in PRE, reflecting dynamic lung hyperinflation. In contrast, IC increased by 0.21 L from rest-to-peak exercise in POST (p=0.034 vs. PRE). Inspiratory reserve volume (expressed as a percentage of forced vital capacity [IRV%FVC]) was lower at any given V̇E during exercise in POST vs. PRE. Clinically-meaningful decreases in intensity ratings of breathlessness were observed during exercise at standardized submaximal power outputs ≥75 watts in POST vs. PRE; for example, by 1.0 and 1.4 Borg 0-10 scale units at 75-watts (p<0.05) and at the highest equivalent power output of 117-watts (p<0.08). However, these differences did not persist when breathlessness was examined in relation to V̇E. Breathlessness-IRV%FVC curves were rightward shifted during exercise in POST vs. PRE, such that breathlessness intensity ratings were lower at any given IRV%FVC during exercise in POST vs. PRE.Conclusion: Relief of exertional breathlessness following extreme weight loss via bariatric surgery for class III obesity could not be explained by improved breathing mechanics but was mechanistically linked to the reduced metabolic and ventilatory requirements of exercise.Objectifs: Les adultes obèses sont deux à quatre fois plus susceptibles de subir de l'essoufflement qui pourrait limiter leur activité physique comparé à des individus de poids normal. La compréhension des mécanismes physiologiques sur cet essoufflement parmi les chercheurs et professionnels de santé demeurent toutefois limitées. Donc, le but de cette étude était de mieux comprendre les mécanismes physiologiques de l'essoufflement chez les individus obèses en examinant les effets de la perte de poids extrême à la suite d'une intervention de chirurgie bariatrique pour l'obésité de classe III (IMC ≥ 40 kg/m2). À cet effet, nous avons évalué les responses physiologiques et l'essoufflement lors d'un test d'exercice cardio-pulmonaire à base de cycloergomètre. Nous postulons que le soulagement de l'essoufflement à l'effort à la suite d'une chirurgie bariatrique serait principalement lié à la réduction des besoins métabolique et ventilatoires durant l'exercice, tandis que les changements de mécanismes respiratoires statique et dynamique seraient moins important. Méthodologie: Nous avons comparé les paramètres cardiaques, métaboliques, le schéma respiratoire, les volumes pulmonaires ainsi que le taux d'essoufflement atteint à la limite symptomatique lors d'un test d'exercice à intensité progressive sur une bicyclette ergométrique (25 watts/2 min) avec 6 adultes obèses (3 femmes) âgés de 43,7±2,8 ans (moyenne ± SEM) avant (PRÉ) et 3 mois après la chirurgie bariatrique (POST). Les tests de fonction pulmonaire et les paramètres de composition corporelle ont également été évalués PRÉ-POST.Résultats: Par rapport au PRÉ, la masse corporelle, l'IMC, la masse grasse et la masse maigre ont diminué en moyenne de 23,8 kg (129,4 ± 6,2 vs 105,6 ± 5,8 kg), 8,7 kg / m2 (47,1 ± 1,6 vs 38,4 ± 1,6 kg / m2), 18,5 kg (61,6 ± 4,6 vs 43,1 ± 4,8 kg) et 4,4 kg (62,2 ± 4,1 vs 57,8 ± 4,6 kg) dans le POST, respectivement (tous p <0,05). La puissance de sortie maximale n'était pas significativement différente entre le POST et PRÉ: 154 ± 21 vs 133 ± 11 watts (p = 0,185). En dehors de quelques exceptions, la fréquence cardiaque, le taux d'absorption d'oxygène, le taux de production de dioxyde de carbone et la ventilation (V̇E) étaient plus faibles pendant l'exercice durant le POST comparativement au PRÉ. La réduction de la réponse V̇E durant l'exercice dans le POST par rapport au PRÉ reflète l'utilisation d'un schéma respiratoire relativement plus lent (moins de tachypnée). Le fait que la capacité inspiratoire (CI) entre les exercices de repos et les exercices de pointe a diminué de 0,13 L révèle une hyperinflation pulmonaire dynamique. En revanche, la CI a augmenté de 0,21 litre lors de l'exercice de repos à l'exercice maximale dans le POST (p = 0,034 vs PRÉ). Le volume de réserve inspiratoire (exprimé en pourcentage de la capacité vitale forcée [% CVF]) était plus faible à toute mesure de V̇E durant l'exercice dans le POST vs PRÉ. Des diminutions cliniquement significatives sur l'intensité de l'essoufflement ont été observées pendant l'exercice à des puissances de sortie sous-maximales normalisées ≥75 watts en POST vs PRÉ; par exemple, par 1,0 et 1,4 unités d'échelle Borg 0-10 à 75 watts (p <0,05) et à la puissance de sortie équivalente la plus élevée de 117 watts (p <0,08). Cependant, ces différences n'ont pas persisté lorsque l'essoufflement a été examiné par rapport à la V̇E. Les courbes associées à l'essoufflement et IRV%CVF ont été décalées vers la droite pendant l'exercice dans POST vs. PRÉ, de telle sorte que les taux d'intensité d'essoufflement étaient plus faibles à tout IRV% de CVF pendant l'exercice du POST comparativement au PRÉ.Conclusion: Le soulagement de l'essoufflement à l'effort après une perte de poids extrême par chirurgie bariatrique pour l'obésité de classe III ne pouvait être expliquer par une amélioration des mécanismes pulmonaires, mais était plutôt lié à une réduction d'exigences métaboliques et ventilatoires durant l'exercice
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
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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