1,721,051 research outputs found
The role of occupational exposure on chronic obstructive pulmonary disease in middle-aged adults
Get PDF© 2017 Dr. Sheikh Mohammad AlifChronic Obstructive Pulmonary Disease (COPD) contributes significantly to the global burden of disease. COPD is characterized by the presence of fixed airflow obstruction (AO) as measured by spirometry and defined by irreversible reduction in the post-bronchodilator (BD) ratio between the forced expiratory volume in one second and forced vital capacity (FEV1/FVC). Chronic bronchitis, chronic respiratory symptoms and lung function decline over time are also significant predictors of COPD. However, they are also considered separate conditions as these may exist with normal lung function. Smoking is the main risk factor for COPD but a large number of people with COPD are never smokers, so other factors are contributing to the disease burden. Occupational exposure is one of the known important preventable risk factor for this disease. Understanding how occupational exposures contribute to the overall risk of COPD in the general population is essential to be able to gain a greater understanding of COPD etiology and to be able to identify high-risk occupational groups. Population-based studies have found evidence of a relationship between some occupational exposures and COPD. However, a critical review of literature presented in Chapter 2, identified that studies to date investigating these relationships have had some significant limitations including lack of post-BD measurement, limited use of lifetime work history and cumulative exposure assessment. Furthermore, some common occupational exposures with known respiratory impacts have not been investigated in relation to fixed AO with adequate consideration of asthma and lung function decline. Therefore, the aim of my doctoral work was to investigate the effects of occupational exposures on COPD using robust definitions of COPD, chronic bronchitis, and lung function decline and to explore if any effect modification existed.
My systematic review and meta-analyses (Chapter 3) identified an association between low exposure to mineral dust and high exposure to gases/fumes and COPD, and both low and high exposure to biological dust and mineral dust were associated with chronic bronchitis. This work further helped to identify some of the major gaps in the literature that I have addressed in my subsequent analysis.
In Chapter 4, I used data from the population-based Tasmanian Longitudinal Health Study (TAHS). Lifetime work history calendars were collected at age 45 years, and occupational exposures were assigned using the ALOHA plus Job Exposure Matrix and defined as ever exposed and cumulative exposure-unit years. Multivariable linear and logistic regressions were used to investigate the associations adjusting for possible confounders.
In Chapter 5, I examined the associations between occupational exposure and COPD defined by fixed AO, chronic bronchitis, and respiratory symptoms. I found consistent significant associations between ever exposure and cumulative exposure-unit years to pesticides and herbicides and fixed AO, chronic bronchitis, and respiratory symptoms. I also found evidence of effect modification by current asthma for the association between biological dust, mineral dust, and gases/fumes and fixed AO.
In Chapter 6, I examined the association between exposure to solvents and metals and COPD as defined by fixed AO and gas transfer factor. I found an association between ever exposure to metals and fixed AO. Interestingly I also found an association between increasing cumulative exposure-unit years to chlorinated solvents and fixed AO and fixed AO plus low DLco but only in women, not in men.
In Chapter 7, I investigated the association between occupational exposures and lung function decline between age 45 and 50 years. I found an association between both ever exposure and cumulative exposure-unit years to aromatic solvents and a greater decline in lung function. I also found that increasing cumulative exposure-unit years to aromatic solvents were associated with a greater lung function decline in women, but not in men.
Collectively these findings have strengthened and have filled some major gaps in our understanding of the links between overall occupational exposure and the development of COPD in an adult population. I have confirmed in my study that exposure to pesticides is a risk factor for COPD with solvents and metals exposure also linked to an increased risk of COPD. Importantly, my findings suggest that women are at a greater risk of COPD when exposed to solvents. These findings lead me to make several important public health recommendations. Firstly, workplaces need to be monitored to ensure exposure to pesticides and solvents is reduced via adequate ventilation, storage, and usage solutions. Secondly, occupational groups with regular and high exposure to these chemicals need to be encouraged to utilize personal protective equipment, together with routine monitoring. By implementation of these control measures, the burden of COPD caused by occupational exposures has the potential to be reduced
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
- …
