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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Ambient air pollution and cardiorespiratory outcomes amongst adult residing in four informal settlements in the Western Province of South Africa

Bagula, Herman Joseph 27 February 2020 (has links)
Background Many studies investigating the relationship between ambient air pollution and cardiorespiratory outcomes have been conducted in developed countries despite more vulnerable populations in low- and middle-income countries especially in Africa. No studies previous studies have been done in South Africa informal settlements. Aim The aim of the study was to investigate the relationship between ambient air pollutant exposure and self-reported cardiorespiratory outcomes amongst adults residing in four informal settlements of the Western Province of South Africa. Methods This cross-sectional study included 572 adults from four informal settlements (Khayelitsha, Marconi Beam, Oudtshoorn and Masiphumele) in the Western Cape, South Africa. The study made use of Land Use Regression to estimate each participant’s exposure to particulate matter of aerodynamic diameter of 2.5µm (PM2.5) and nitrogen dioxide (NO2). A questionnaire was adapted from the European Community Respiratory Health Survey and National Health and Nutrition Examination Survey questionnaire to collect data on self-reported cardiorespiratory outcomes and specific confounding factors of interest. Results The median age the participants was 39 years (Interquartile Range (IQR): 33 - 45) with 88.5% female. The median NO2 level was 22.4 µg/m3 (IQR: 13.3 - 24.1) and the median PM2.5 level was 10.6 µg/m3 (IQR: 8.7 - 13.1). An increase of 10µg/m3 in annual NO2 level was found to be associated with a 2.9 (95%CI: 1.3 to 6.1) odds of having self-reported chest pain, adjusting for PM2.5 and confounders. No other significant association was found indicating an adverse health effect due to air pollution. Conclusion The study found preliminary circumstantial evidence of an association between annual ambient NO2 exposure and self-reported chest pain (a crude proxy of angina related pain), even at levels below both WHO Air Quality Guidelines and the South African National Ambient Air Quality Standards. However, the results should be interpreted cautiously due to the self-reported nature of the outcome measure and the cross-sectional design of the study.
2

Ανάλυση και εξομοίωση επιδημιολογικών μοντέλων εξάπλωσης αυτοαναπαραγόμενων αυτόματων

Θεοδωράκης, Ευτύχιος 26 July 2013 (has links)
Το κάτωθι κείμενο πραγματεύεται το φαινόμενο της εξάπλωσης αυτοαναπαραγόμενων αυτομάτων σε δίκτυα. Αρχικά προβαίνουμε σε μια εισαγωγή στα αυτοαναπαραγόμενα προγράμματα και στο περιβάλλον στο οποίο εξαπλώνονται και εν συνεχεία εμβαθύνουμε στον τρόπο με τον οποίο προσεγγίζουμε το φαινόμενο. Μελετάμε μεθόδους ανίχνευσης με χρήση φίλτρων Kalman και εντροπίας. Τέλος, ασχολούμαστε με μια σειρά παιγνίων και σεναρίων με σκοπό την ανάδειξη συγκεκριμένων πλευρών του όλου προβλήματος και την τροπή που παίρνει στις μέρες μας. Εν κατακλείδι, η παρούσα διπλωματική εργασία τονίζει βασικές ιδιότητες που χαρακτηρίζουν την διάδοση και εισάγει νέες βοηθητικές έννοιες και μοντέλα, με στόχο την κατανόηση και τον ενστερνισμό του πνεύματος των εξελίξεων στα σύγχρονα worms και viruses. / The text below considers the phenomenon of propagation of self replicating automata. We begin with an introduction to self replicating programs and to the environment in which they propagate and then we delve and explain the ways of approaching the phenomenon. We study detection methods via the use of Kalman filters and estimation of entropy. Finally, a series of games and scenarios are introduced and studied, in order to enlighten certain aspects of the problem and its current direction. In conclusion, this diploma thesis marks basic properties of the propagation and introduces auxiliary concepts and new models, having as a goal the comprehension and the adoption of the spirit of evolution of modern worms and viruses.

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