1,721,070 research outputs found
Adenosine : a putative mediator of bronchoconstriction in asthma
No full textAdenosine causes bronchoconstriction when inhaled by asthmatic subjects, and is released from lung tissue during hypoxia and antigen challenge in vitro. This thesis investigates the possible role of adenosine in the pathogenesis of asthma. The protective effect of a muscarinic cholinergic antagonist, ipratropium bromide (IB) from inhaled adenosine - and methacholine-induced bronchoconstriction in asthma was studied. Inhaled IB protected from methacholine- but not adenosine-induced bronchoconstriction. Parasympathetically mediated bronchoconstriction is therefore unlikely to account for adenosine's airway effect in asthma. The capacity of theophylline, a bronchodilator and a competative antagonist of adenosine at its cell surface receptors, to protect asthmatic subjects from adenosine- and histamine-induced bronchoconstriction was determined. At therapeutic plasma concentrations theophylline protected against both bronchoconstrictor stimuli but exerted a greater protective effect against adenosine. Thus adenosine may mediate bronchoconstriction by an action on its receptors. Asthmatic airways are infiltrated with inflammatory cells. Human leucocytes prelabelled with (3H)-adenine when activated with the calcium ionophore A23187 released labelled hypoxanthine, inosine and adenosine which was associated with a dose-related release of histamine. The chemotactic peptide of f-MLP whilst inducing histamine release had an inconstant effect on release of label. In four of five experiments f-MLP produced a transient early increase in label release but in the remaining experiment no significant release was observed. Anti-human IgE failed to induce significant label release despite releasing histamine. Activated leucocytes are therefore a potential source of adenosine in asthma. Plasma concentrations of adenosine and inosine in asthmatic subjects during bronchial provocation with antigen and methacholine were measured by HPLC. Following both bronchoconstrictor stimuli adenosine levels rose significantly whereas inosine levels were unchanged. The time-course of the airway and plasma adenosine response differed following each bronchial provocant. Antigen inhalation was associated with both a slower onset of bronchoconstriction and a more rapid increase in plasma adenosine, when compared to methacholine challenge. These studies support the hypothesis that adenosine may contribute as a bronchoconstrictor mediator in asthma.</p
Tar sandstone investigation in southwestern Uinta Basin
No full textreportDuring the month of July 1972, the author assisted by Jonathan Mann studied the oil impregnated sandstone (hereafter OISS) deposits in the Lower Unit of the Parachute Creek Member of the Green River Formation on the southwestern edge of the Uinta Basin, along the Roan Cliffs and within the Roan Plateau. Careful mapping was conducted to determine the extent of the Sunnyside OISS deposit and to relate it to other deposits in the general vicinity. In addition to this mapping, which was restricted to the Flat Canyon and Sunnyside 15 min. quadrangles, (correlation investigations? ) were carried out in Nine Mile Canyon, Argyle Canyon, Indian Canyon, and at the headwaters of Avintaquin Canyon near Reservation Ridge (see USGS 7 1/2 min. quadrangles Gray Head Peak, 1969, and Flat Ridge, Utah, 1969). These areas, in this report, are further subdivided into smaller regions (often ridges or canyons) for further expansion of the results of the investigation. A number of the canyons could only be studied by hiking them through, others because of the size of the area studied and time requirements were studied by numerous stops from a four-wheel-drive truck. A field method to categorize the estimated richness of the OISS was used in the mapping: A numeral from I-V was assigned to a deposit, I being void of tar and progressing with each number until very rich OISS would be classed as V
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
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