Dissertations / Theses: 'Determinant of exposures'

1

Alwis, Kuruppuge Udeni. "Occupational Exposure to Wood Dust." Thesis, The University of Sydney, 1998. http://hdl.handle.net/2123/392.

Full text

Abstract:

ABSTRACT Occupational exposure to wood dust and biohazards associated with wood dust (endotoxins, (1->3)-b-D-glucans, Gram (-)ve bacteria and fungi), their correlation to respiratory function, and symptoms among woodworkers have been investigated in the present study. Wood dust, endotoxins, and allergenic fungi are the main hazards found in woodworking environments. Relatively very few studies have been done on wood dust exposure. The present study was designed to comprehensively investigate the health effects of wood dust exposure, and in particular provide new information regarding: Exposure to (1->3)-b-D-glucans in an occupational environment; Levels of exposure to wood dust and biohazards associated with wood dust in different woodworking environments; Correlations among personal exposures, especially correlations between (1->3)-b-D-glucans and fungi exposures, and endotoxins and Gram (-)ve bacteria exposures; Effects of personal exposure to biohazards on lung function; Effects of personal exposure to biohazards on work-related symptoms; and Determinants of inhalable exposures (provide which factors in the environment influence the personal inhalable exposures). Workers at four different woodworking processes; two logging sites, four sawmills, one major woodchipping operation and five joineries situated in the state of New South Wales in Australia were studied for personal exposure to inhalable dust (n=182) and respirable dust (n=81), fungi (n=120), Gram (-)ve bacteria (n=120), inhalable endotoxin (n=160), respirable endotoxin (n=79), inhalable (1->3)-b-D-glucan (n=105), and respirable (1->3)-b-D-glucan (n=62). The workers (n=168) were also tested for lung function. A questionnaire study (n=195) was carried out to determine the prevalence of work-related symptoms. The geometric mean inhalable exposure at logging sites was 0.56 mg/m3 (n=7), sawmills 1.59 mg/m3 (n=93), the woodchipping mill 1.86 mg/m3 (n=9) and joineries 3.68 mg/m3 (n=66). Overall, sixty two percent of the exposures exceeded the current standards. Among joineries, 95% of the hardwood exposures and 35% of the softwood exposures were above the relevant standards. Compared with green mills, the percentage of samples, which exceeded the hardwood standard was high for dry mills (70% in dry mills, 50% in green mills). The respirable dust exposures were high at the joineries compared with the other worksites. Exposure levels to fungi at logging sites and sawmills were in the range 103-104 cfu/m3, woodchipping 103-105 cfu/m3 and joineries 102-104 cfu/m3. The predominant fungi found at sawmills were Penicillium spp. High exposure levels of Aureobasidium pullulans were also found at two sawmills. At the woodchipping mill the predominant species were Aspergillus fumigatus, Penicillium spp., and Paecilomyces spp. The sawmills, which employed kiln drying processes, had lower exposure levels of fungi compared with the green mills. Those workplaces which had efficient dust control systems showed less exposure to fungi and bacteria. Although mean endotoxin levels were lower than the suggested threshold value of 20 ng/m3, some personal exposures at sawmills and joineries exceeded the threshold limit value. The mean inhalable (1->3)-b-D-glucan level at the woodchipping mill was 2.32 ng/m3, at sawmills 1.37 ng/m3, at logging sites 2.02 ng/m3, and at joineries 0.43 ng/m3. For the respirable size fraction, mean endotoxin and mean (1->3)-b-D-glucan concentrations were much lower, being similar to observed dust concentrations. Significant correlations were found between mean inhalable endotoxin and Gram (-)ve bacteria levels (p<0.0001), and mean airborne inhalable (1->3)-b-D-glucan and fungi levels (p=0.0003). The correlations between mean respirable endotoxin levels vs Gram (-)ve bacteria exposure levels (p=0.005), and respirable (1->3)-b-D-glucan exposure levels vs total fungi levels (p=0.005) were also significant. Significant correlations were found between lung function and personal exposures. Multivariate analyses showed that the effect of all the personal exposures on cross-shift decrements in lung function was more prominent among sawmill and chip mill workers compared with joinery workers. Woodworkers had markedly high prevalence of cough, phlegm, chronic bronchitis, frequent headaches, throat and eye irritations, and nasal symptoms compared with controls. Among the woodworkers, smokers had a high prevalence of chronic bronchitis (20%) compared with non-smokers (10%). Some workers also reported a variety of allergy problems due to exposure to various types of wood dust. Both joinery workers and sawmill and chip mill workers revealed significant correlations between work-related symptoms and personal exposures. Chronic bronchitis was significantly correlated with personal exposure to wood dust, endotoxin, (1->3)-b-D-glucan, fungi, and Gram (-)ve bacteria among joinery workers. Whereas among sawmill workers chronic bronchitis was significantly correlated with personal exposure to endotoxin, (1->3)-b-D-glucan, and fungi. Woodworkers showed significant positive correlations between percentage cross-shift change (decrease) in lung function and respiratory symptoms. Significant inverse correlations were also found among percentage predicted lung function and respiratory symptoms. The elevated inhalable dust exposures observed in this study can be explained by a combination of factors, including: lack of awareness of potential health effects of wood dust exposure among both management and workers, aging equipment, inadequate and ineffective dust extraction systems or usually none especially for hand held tools, poor maintenance of the ventilation system in some, non-segregation of dusty processes, dry sweeping, and the use of compressed air jets. The determinant-of-exposure analysis confirmed the field observations. The significant determinants of personal inhalable dust exposures (n=163) were found to be: local exhaust ventilation, job title, use of hand-held tools, cleaning method used, use of compressed air, and green or dry wood processed. Type of wood processed was not found to be statistically significant. A majority of workers (~90%) did not wear appropriate respirators approved for wood dust, while the workers who did wear them, used them on average less than 50% of the time. Workers should be protected by controlling dust at its source. When exposure to wood dust cannot be avoided, engineering controls should be supplemented with the use of appropriate personal protective equipment.

APA, Harvard, Vancouver, ISO, and other styles

2

Alwis, Kuruppuge Udeni. "Occupational Exposure to Wood Dust." University of Sydney, Department of Public Health and Community Medicine, 1998. http://hdl.handle.net/2123/392.

Full text

Abstract:

ABSTRACT Occupational exposure to wood dust and biohazards associated with wood dust (endotoxins, (1->3)-b-D-glucans, Gram (-)ve bacteria and fungi), their correlation to respiratory function, and symptoms among woodworkers have been investigated in the present study. Wood dust, endotoxins, and allergenic fungi are the main hazards found in woodworking environments. Relatively very few studies have been done on wood dust exposure. The present study was designed to comprehensively investigate the health effects of wood dust exposure, and in particular provide new information regarding: Exposure to (1->3)-b-D-glucans in an occupational environment; Levels of exposure to wood dust and biohazards associated with wood dust in different woodworking environments; Correlations among personal exposures, especially correlations between (1->3)-b-D-glucans and fungi exposures, and endotoxins and Gram (-)ve bacteria exposures; Effects of personal exposure to biohazards on lung function; Effects of personal exposure to biohazards on work-related symptoms; and Determinants of inhalable exposures (provide which factors in the environment influence the personal inhalable exposures). Workers at four different woodworking processes; two logging sites, four sawmills, one major woodchipping operation and five joineries situated in the state of New South Wales in Australia were studied for personal exposure to inhalable dust (n=182) and respirable dust (n=81), fungi (n=120), Gram (-)ve bacteria (n=120), inhalable endotoxin (n=160), respirable endotoxin (n=79), inhalable (1->3)-b-D-glucan (n=105), and respirable (1->3)-b-D-glucan (n=62). The workers (n=168) were also tested for lung function. A questionnaire study (n=195) was carried out to determine the prevalence of work-related symptoms. The geometric mean inhalable exposure at logging sites was 0.56 mg/m3 (n=7), sawmills 1.59 mg/m3 (n=93), the woodchipping mill 1.86 mg/m3 (n=9) and joineries 3.68 mg/m3 (n=66). Overall, sixty two percent of the exposures exceeded the current standards. Among joineries, 95% of the hardwood exposures and 35% of the softwood exposures were above the relevant standards. Compared with green mills, the percentage of samples, which exceeded the hardwood standard was high for dry mills (70% in dry mills, 50% in green mills). The respirable dust exposures were high at the joineries compared with the other worksites. Exposure levels to fungi at logging sites and sawmills were in the range 103-104 cfu/m3, woodchipping 103-105 cfu/m3 and joineries 102-104 cfu/m3. The predominant fungi found at sawmills were Penicillium spp. High exposure levels of Aureobasidium pullulans were also found at two sawmills. At the woodchipping mill the predominant species were Aspergillus fumigatus, Penicillium spp., and Paecilomyces spp. The sawmills, which employed kiln drying processes, had lower exposure levels of fungi compared with the green mills. Those workplaces which had efficient dust control systems showed less exposure to fungi and bacteria. Although mean endotoxin levels were lower than the suggested threshold value of 20 ng/m3, some personal exposures at sawmills and joineries exceeded the threshold limit value. The mean inhalable (1->3)-b-D-glucan level at the woodchipping mill was 2.32 ng/m3, at sawmills 1.37 ng/m3, at logging sites 2.02 ng/m3, and at joineries 0.43 ng/m3. For the respirable size fraction, mean endotoxin and mean (1->3)-b-D-glucan concentrations were much lower, being similar to observed dust concentrations. Significant correlations were found between mean inhalable endotoxin and Gram (-)ve bacteria levels (p<0.0001), and mean airborne inhalable (1->3)-b-D-glucan and fungi levels (p=0.0003). The correlations between mean respirable endotoxin levels vs Gram (-)ve bacteria exposure levels (p=0.005), and respirable (1->3)-b-D-glucan exposure levels vs total fungi levels (p=0.005) were also significant. Significant correlations were found between lung function and personal exposures. Multivariate analyses showed that the effect of all the personal exposures on cross-shift decrements in lung function was more prominent among sawmill and chip mill workers compared with joinery workers. Woodworkers had markedly high prevalence of cough, phlegm, chronic bronchitis, frequent headaches, throat and eye irritations, and nasal symptoms compared with controls. Among the woodworkers, smokers had a high prevalence of chronic bronchitis (20%) compared with non-smokers (10%). Some workers also reported a variety of allergy problems due to exposure to various types of wood dust. Both joinery workers and sawmill and chip mill workers revealed significant correlations between work-related symptoms and personal exposures. Chronic bronchitis was significantly correlated with personal exposure to wood dust, endotoxin, (1->3)-b-D-glucan, fungi, and Gram (-)ve bacteria among joinery workers. Whereas among sawmill workers chronic bronchitis was significantly correlated with personal exposure to endotoxin, (1->3)-b-D-glucan, and fungi. Woodworkers showed significant positive correlations between percentage cross-shift change (decrease) in lung function and respiratory symptoms. Significant inverse correlations were also found among percentage predicted lung function and respiratory symptoms. The elevated inhalable dust exposures observed in this study can be explained by a combination of factors, including: lack of awareness of potential health effects of wood dust exposure among both management and workers, aging equipment, inadequate and ineffective dust extraction systems or usually none especially for hand held tools, poor maintenance of the ventilation system in some, non-segregation of dusty processes, dry sweeping, and the use of compressed air jets. The determinant-of-exposure analysis confirmed the field observations. The significant determinants of personal inhalable dust exposures (n=163) were found to be: local exhaust ventilation, job title, use of hand-held tools, cleaning method used, use of compressed air, and green or dry wood processed. Type of wood processed was not found to be statistically significant. A majority of workers (~90%) did not wear appropriate respirators approved for wood dust, while the workers who did wear them, used them on average less than 50% of the time. Workers should be protected by controlling dust at its source. When exposure to wood dust cannot be avoided, engineering controls should be supplemented with the use of appropriate personal protective equipment.

APA, Harvard, Vancouver, ISO, and other styles

3

Moss, Darren. "Cellular determinants of raltegravir exposure." Thesis, University of Liverpool, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632138.

Full text

Abstract:

HIV infection remains a worldwide concern and new drug treatments are required to tackle drug resistance and to reduce drug-associated host toxicity. Raltegravir, a new anti-HIV drug which targets the HIV integrase enzyme, is now being used in anti-HIV treatment and has shown impressive efficacy and low toxicity. However, the drug shows high pharmacokinetic (PK) variability between subjects and it has been difficult to associate PK parameters with treatment outcome. The aim of this thesis was to improve the current understanding of the factors influencing raltegravir PK and cellular exposure using in vitro and in silico techniques.

APA, Harvard, Vancouver, ISO, and other styles

4

Sabbath, Erika. "Occupational Exposures as Social Determinants of Aging." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA11T018.

Full text

Abstract:

Cette thèse s’intéresse à la contribution des expositions professionnelles —chimiques, biomécaniques, et psychosociaux—tout au long de la vie dans les inégalités sociales de santé liés au vieillissement. Les trois papiers de la thèse essaient de combler les lacunes dans les connaissances sur les effets à long terme des expositions professionnelles et la contribution des expositions individuelles et conjointes dans ces inégalités. Le premier papier cherche à savoir si le niveau d’éducation atteint dans l’enfance modifie l’effet de l’exposition professionnelle aux solvants au cours de la carrière sur la fonction cognitive après 55 ans.. Nous avons trouvé que l’effet de l’exposition aux solvants sur la fonction cognitive était différent selon le niveau d’éducation.. Le deuxième papier discute les effets combinés des expositions biomécaniques et psychosociaux au cours de la vie professionnelle sur la santé physique et fonctionnelle après la retraite. Nous avons trouvé qu’une forte exposition à la fois aux risques physiques et psychosociaux au cours de la vie active est associée à une capacité fonctionnelle bien plus faible après la retraite que l’exposition à un seul type de risques. Aussi, l’effet était différent chez les hommes et chez les femmes. Le troisième papier est un papier méthodologique qui discute des alternatives aux formes longues des échelles généralement utilisées pour évaluer les expositions biomécaniques au travail. Nous avons cherché à vérifier si la question « Trouvez-vous votre travail fatiguant physiquement?» pourrait être une mesure de substitution acceptable pour évaluer des expositions détaillées.. Nous avons comparé la mesure à un item à une mesure plus complète de 38 expositions spécifiques dans huit domaines. Nous avons trouvé que la mesure à un item était plus valide chez les participants fortement exposés à des contraintes biomécaniques de travail. En somme, cette thèse a montré que les expositions professionnelles peuvent à la fois exacerber les disparités existantes en matière de santé et les perpétuer au delà de la retraite
This dissertation focuses on how occupational exposures throughout the lifecourse—chemical, physical, and psychosocial—contribute to social patterns in aging outcomes, addressing the gap in knowledge about lasting effects of occupational exposures and the contribution of individual and combined exposures to social patterns in aging. The first paper explores whether childhood educational attainment modifies effects of occupational solvent exposure during the career on cognitive function after age 55. We found differential effects of solvent exposure on cognition by educational attainment. The second paper looks at combined physical and psychosocial exposures during working life and effects on physical health and functioning after retirement. This paper finds that high exposure to both physical and psychosocial hazards at work is associated with worse functional capacity in retirement than exposure to either one separately; the pattern of this relationship differs for men and women. The third paper is a methodology paper exploring alternatives to extensive testing batteries often used to evaluate physical workplace exposures. We tested whether the question “Do you find your work physically strenuous?” was an acceptable proxy measure for more detailed exposure assessments by comparing the measure to a comprehensive self-report measure of 38 specific biomechanical strains across eight domains. We found that the measure was most valid in the populations that were most highly exposed to physical strains at work. In general, this dissertation found that occupational exposures can exacerbate existing disparities in health and perpetuate disparities into and beyond retirement

APA, Harvard, Vancouver, ISO, and other styles

5

Agena, Mahmoud B. "Neonatal exposure to pathogens : determining key virulence factors." Thesis, Nottingham Trent University, 2017. http://irep.ntu.ac.uk/id/eprint/32859/.

Full text

Abstract:

The neonatal stage is the most critical period for infections, with mortality rate of up to 45% amongst children under five years. The genus Cronobacter has been involved in many outbreaks in neonatal intensive care units, with recorded meningitis, bacteraemia, and necrotizing enterocolitis (NEC). Although this genus was deeply investigated in vitro with different cell lines, until now, few researches have been focused on the use of H4 cell line, which is supposed to be more representative of neonatal response. Therefore, the present PhD study aimed to investigate the interaction of selected clinical isolates and the seven-type species of the genus Cronobacter, as well as one E. coli K1 isolate with H4 cells compared with Caco-2 cell line. Physiological analyses revealed most of the strains to be motile, and capsule and biofilm producers. A link between capsule production and serum resistance was shown by some strains. Strains were examined regarding their attachment, invasion, translocation and cytotoxicity as well as for the role of host cytoskeleton in the invasion process to both cell lines. All strains, especially C. sakazakii ST12 (696 and 703) were significantly more adhesive to the H4 than Caco-2 cells; this sequence type has previously been associated with neonatal NEC. Importantly, this study indicated that some clinical strains were more invasive to H4 than Caco-2 cells such as C. sakazakii 767 (meningitis) and 701 (NECIII). Moreover, attachment and invasion of E.coli were higher in H4 than Caco-2 cells. High attachment and invasion is potentially linked with excessive inflammatory response and NEC development in neonates. Most studied strains were able to translocate human cell lines, causing necrotic damage in the polarized monolayer. More importantly, translocation of blood or meningitic isolates such as C. sakazakii 709, C. malonaticus 1569, C.turicensis 564 was higher via H4 compared with Caco-2 cells. However, translocation of E. coli K1 strain 939 was similar in both cell lines. Most of the bacterial strains were cytotoxic to both cell lines and C. sakazakii ST3 strain 798 showed an ability to kill H4 cells up to 90-fold of blank, and about 70-fold when co-cultured with Caco-2 cells. Results suggests that intact bacterial cells that able to produce new proteins while in direct contact with the host cells is essential for the cytotoxicity, indicating the potential involvement of an active secretion system in cytotoxicity. Cytochalasin D and Colchicine mostly inhibited invasion to the H4 cells and enhanced the invasion of some strains to Caco-2 up to five-fold. Only Nocodazole significantly enhanced the invasion of some strains to H4 cell, and variably effected strains’ invasion to Caco-2. Data obtained from human cytoskeleton inhibitors experiments suggested the possible strain specific role of inhibitors on both cell lines, and strains may encode different pathways for uptake, with the possible involvement of eukaryotic receptors that recognize the invading bacteria. This study indicated that the response of the H4 cells to bacterial challenge and production of inflammatory cytokines was higher than Caco-2 cells. The H4 cells produced more IL-1-β, IL-4, IL-6, IL-8, IP-10, MCP-1, and EGF-α. Furthermore, tested strains (n=12) variably affected the expression of human Toll-like receptors (TLRs) and NF-kB subunits 1 and 2 in both cell lines, only C. sakazakii strain 709 upregulated expression of TLR1-4 in H4 cells and was the strongest inducer of receptor gene expression in both cell lines. More importantly, the upregulation of NF-kB subunits 1 is more likely related to the increased inflammatory cytokine production, while no link with subunit 2. However, TLR-1 was not expressed in Caco-2 in response to these strains, which needs further investigation. The effect of the E. coli K1 strain 939 on the TLRs expression was varied and no specific pattern was detected, but in some cases it showed similarity to the effect of C. sakazakii 767 which is also linked with neonatal meningitis. As most of the investigated bacterial strains displayed virulence factors with H4 cells closely related to their clinical pathology, the present study provides an important initial work to introduce H4 cells as a new modle for neonatal cell lines to analyse neonatal infections.

APA, Harvard, Vancouver, ISO, and other styles

6

Zafar, Janjua Naveed. "Prenatal lead exposure in Karachi magnitude, determinants and effect on birth weight /." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/zafar.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Bostwick, Stephanie L. "Determining hydrogen peroxide exposure of employees at Company XYZ." Online version, 2002. http://www.uwstout.edu/lib/thesis/2002/2002bostwicks.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Lozier, Matthew Joiner. "Determinants of Atrazine contamination in Iowa homes and occupational exposure in Central America." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/848.

Full text

Abstract:

Background : Atrazine is an agricultural herbicide used extensively in corn production worldwide. Atrazine is an endocrine disruptor and has been linked to many other deleterious health outcomes. Exposure assessment studies have been carried out in Iowa among farm and non-farm populations. However, commercial pesticide applicators have been left out of those studies. Atrazine is also used in developing countries in grain production. In developing countries there is great concern about acute pesticide poisonings, but chronic exposure to less acutely toxic pesticides has not been studied extensively. This study assessed the in-home contamination of atrazine among commercial pesticide applicators in Iowa and then quantitatively analyzed these results with results from similar studies. Occupational inhalation exposure to atrazine was also assessed in Honduras. Methods : Dust samples were taken from 29 commercial pesticide applicator households in four different locations. This sampling was done once during the atrazine application season and again six months later during winter months to assess atrazine persistence. Occupational and household characteristics were analyzed for associations with atrazine dust levels. Data from two previous studies that analyzed farm and non-farm household dust samples for atrazine were combined with data from the commercial applicator's homes. This new and larger dataset was analyzed to identify which population has the greatest risk for take-home atrazine exposure and what determinants were associated with in-home atrazine dust levels. Lastly, corn production practices in Honduras were evaluated and personal air samples were taken from pesticide applicators during atrazine application to assess inhalation exposure. Results : The first study found that atrazine levels persist into the winter months in the homes of commercial applicators. Atrazine handling (days, pounds, and acres sprayed) were all positively associated with in-home atrazine levels. Commercial applicators that change their shoes inside had higher atrazine levels. More frequent floor cleaning was associated with lower atrazine levels. The second study identified commercial applicators' homes as the most contaminated compared with farmers who apply atrazine to their own land, farmers who hire out atrazine application, and non-farm homes. Farmers that apply their own atrazine also had significantly higher atrazine levels in their homes. The association between atrazine handling and household atrazine levels was highly significant in this study (p < 0.001). In Honduras, atrazine is applied to corn fields with tractor/boom equipment and manual backpack sprayers. Despite applying about one-fifteenth the amount of atrazine, backpack sprayers are exposed to nearly equal amounts of atrazine via inhalation exposure and likely have greater exposure via the dermal route. Among backpack sprayers, which type of spray nozzle used is associated with inhalation exposure. Among tractor/boom applicators, tractor drivers have much lower inhalation exposure than workers who operate and observe the boom. Conclusions : The amount of atrazine handled is the most important determinant for predicting in-home atrazine levels in Iowa. Ubiquitous atrazine contamination and its distribution within homes and among household type provide strong evidence for the take-home pathway. While some improvements have been made in Honduras regarding pesticide application, poor farm workers and small farmers still use antiquated pesticide application techniques which leads to a higher risk of inhalation and dermal exposure.

APA, Harvard, Vancouver, ISO, and other styles

9

Lakshminarayan, Sooraj T. K. "Distribution and determinants of Atrazine exposure among Central Ohio farm families." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1407234952.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Nieuwenhuijsen, Marius Joannes. "Exposure to aeroallergens : determinants, exposure levels, and skin prick test reactions in bakeries, flour mills and research institutes." Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241827.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Patel, Shalini. "Demographic, Dietary, and Lifestyle Determinants of Vitamin D Status in the US Population: National Health and Nutrition Examination Survey, 2005-2006." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/nutrition_theses/37.

Full text

Abstract:

Background: Determinants of vitamin D status are of interest when studying the epidemiology of disease in population groups because vitamin D is now recognized to decrease the risk of diseases such as osteoporosis, cancer, and cardiovascular disease. Understanding modifiable determinants of vitamin D status are important for managing vitamin D deficiency at the individual level and for addressing this issue at population level. Objective: The objective of this study was to evaluate the associations between serum vitamin D status (deficiency and insufficiency) and distinct demographic, dietary, and lifestyle characteristics of adults in the United States using a large, nationally representative sample survey, the National Health and Nutrition Examination Survey (NHANES) 2005-2006. Methods: The study sample consisted of 2340 adults aged 20-59 who had serum 25(OH)D measured and who had completed various questionnaires concerning dietary intake of vitamin D and other lifestyle factors. Multivariate logistic regression was used to estimate the odds ratio (OR) of vitamin D deficiency, insufficiency, and sufficiency in adults based on distinct demographic, dietary, and lifestyle characteristics. Statistical significance was set at α < 0.05. Results: The prevalence of vitamin D deficiency was higher in obese adults than in underweight to normal weight adults (50.9% ± 4.57 vs. 29.3% ± 3.57), higher in adults who reported no sunburns than in adults who reported ≥ 3 sunburns (49.9% ± 3.82 vs. 18.0% ± 3.07), and higher in adults who use sun protective measures regularly than in adults who do not (48.4% ± 3.93 vs. 27.0% ± 3.75). The prevalence of vitamin D deficiency increased as dietary intake of vitamin D decreased. Non-Hispanic black adults were significantly more likely to be vitamin D deficient (OR = 45.27, 95% CI = 17.27-118.64) and insufficient (OR = 9.37, 95% CI = 3.43-25.61) than non-Hispanic white adults. Significant positive associations were found between vitamin D deficiency and several characteristics, namely obesity (OR = 7.43, 95% CI = 4.33-12.77), physical inactivity (OR = 1.63, 95% CI = 1.03-2.58) poor dietary vitamin D intake (OR = 2.34, 95% CI = 1.44-3.81), non-supplement use or supplement use with a low amount of vitamin D (OR = 1.75, 95% CI = 1.05-2.89), and activities that decrease exposure to sunlight (from OR = 2.97, 95% CI = 2.14-4.13 to OR = 5.30, 95% CI = 3.17-8.85). Conclusion: The results of this nationally representative study demonstrate that obesity, physical inactivity, poor dietary intake of vitamin D, and low sunlight exposure increases the risk for vitamin D deficiency in U.S adults. Future studies are needed to investigate whether vitamin D supplementation, sunlight exposure, and vitamin D-fortified foods are efficient in correcting vitamin D deficiency and insufficiency among these groups.

APA, Harvard, Vancouver, ISO, and other styles

12

El-Masry, Ahmed Ahmed. "Foreign exchange rate exposure and its determinants : firm and industry level analysis." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488633.

Full text

Abstract:

Financial theory predicts that a change in an exchange rate should affect the value of a firm or an industry. To a large extent, past research has not supported this theory. which is surprising especially after considering the substantial exchange ratc fluctuations over the last three' decades. This study extends previous research on the foreign exchange rate exposure using a sample of 364 UK nonfinancial companies over the period from January 1981 to December 2001. The impact of the changes (realised and unexpected) in exchange rates on firms' or industries' stock returns is examined. In addition, the movements in bilateral, equally weighted and trade-weighted exchange rate indices arc considered. The findings indicate that a higher percentage ofUK firms and industries arc exposed to contemporaneous exchange rate changes than those reported in previous studies. UK firms' and industries' stock returns are more affected by changes in the ECU. EQW. US$ and JPY exchange rate, and less significantly to the basket of 20 countries' currencies relative to the British pound exchange rate. There is alsO evidence of significant lagged exchange rate exposure. This lagged exchange rate exposure is consistent with findings in previous studies that some market inefficiencies may exist in incorporating exchange rate changes into the returns of firms and industries. This also means that there is possible mispricing of the: exchange rate to firm value relationship by the market. This study also segregates firms and industries based on various variables that might affect their exchange rate exposure. These variables arc divided into two main groups: foreign involvement variables and hedging variables. The results indicate that the extent of firms' foreign activity has an impact on their exchange rate exposure. These findings imply that restructuring foreign operations can reduce firms' exchange rate exposure. The results also reveal that hedging policies are important detenninants of the exchange rate exposure.

APA, Harvard, Vancouver, ISO, and other styles

13

Schembari, Anna 1982. "Ambient air pollution and birth outcomes : Insights on exposure determinants and new outcomes." Doctoral thesis, Universitat Pompeu Fabra, 2014. http://hdl.handle.net/10803/382485.

Full text

Abstract:

Recent epidemiological evidence on effect of air pollution and pregnancy outcomes is inconsistent. Differences in study design, sample size, population characteristics, control for confounders, air pollution measurements and exposure assessment techniques as well as the lack of knowledge on the exact biological mechanism are likely to contribute to the observed heterogeneity. The aim of this project was to better understand the personal exposure determinants and to use refined exposure assessment techniques such as Land Use Regression (LUR) models to assess the impact of air pollution on birth outcomes. Moreover to encompass outcomes that might help in the identification of possible biological mechanisms of the effect of air pollution on fetus development. Ventilation of the house by opening the windows, the time spent cooking and indicators for traffic intensity were re-occurring statistically significant determinants of the personal and indoor pollutants levels. In our studies of air pollution and birth outcomes we were able to identify congenital anomalies groups not systematically studied before and we were the first to include indicators of fat mass at birth. Air pollutants, estimates using LUR, were associated to increased risk of some congenital anomalies of the hearth and with impaired fetal growth.
Les últimes evidències epidemiològiques sobre l’efecte de la contaminació atmosfèrica i els efectes durant l'embaràs són inconsistents. Les diferències en el disseny de l'estudi, la grandària de la mostra, les característiques de la població, el control dels factors de confusió, les mesures de contaminació de l'aire i les tècniques d'avaluació de l'exposició, així com la manca de coneixement sobre el mecanisme biològic exacte, poden contribuir a l'heterogeneïtat dels resultats observats. L'objectiu d'aquest projecte era comprendre millor els determinants de l'exposició personal i utilitzar tècniques millorades d'avaluació d'exposició, com als models de models d’ús del territori (Land Use Regression, LUR) per avaluar els efectes de la contaminació atmosfèrica a la salut del neonat. Alhora incloure els resultats que podrien ajudar en la identificació de possibles mecanismes biològics dels efectes de la contaminació atmosfèrica en el desenvolupament del fetus. Els factors determinants dels nivells de contaminants personals i d'interior, com ventilació de la casa obrint les finestres, el temps dedicat a la cuina i els indicadors de la intensitat del trànsit es tornen a mostrar estadísticament significatius., En els nostres estudis de la contaminació de l'aire i els efectes en la salut en neonats hem estat capaços d'identificar uns grups d'anomalies congènites no estudiades abans de forma sistemàtica i hem estat els primers a incloure indicadors de massa de greix al néixer. Els contaminants de l'aire i les estimacions utilitzant LUR es van associar a un major risc d'algunes anomalies congènites del cor i amb el retard del creixement fetal.

APA, Harvard, Vancouver, ISO, and other styles

14

Stolt, Patrik. "Cigarette smoking and silica exposure as determinants for the development of rheumatoid arthritis /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-082-6/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Hon, Chun-Yip. "Healthcare workers and antineoplastic drugs : evaluating the risks and identifying determinants of exposure." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42505.

Full text

Abstract:

Healthcare workers’ exposure to antineoplastic drugs may occur through handling of the drugs and/or via contact with drug-contaminated surfaces. However, studies have been limited to select departments and/or certain job titles. This may lead to an underestimate of the risk as the drugs circulate within a facility known as the hospital medication system (process flow of drugs). This study aimed to answer the following questions related to antineoplastic drugs and the hospital medication system: 1) is contamination found on surfaces located throughout, 2) are workers throughout occupationally exposed (dermal and urinary contamination), and 3) what factors are associated with surface contamination and occupational exposure? Site observations were conducted to identify which surfaces may be contaminated and the job categories that may contact these surfaces. Wipe samples were collected from potentially-contaminated surfaces and the hands of at-risk healthcare workers. Urine samples were collected from these same workers. Participants were asked to complete a questionnaire regarding their knowledge and usual protective habits regarding antineoplastic drugs and surveyed about contact with these agents on their work shift. Drug residual was measurable on surfaces located throughout the hospital medication system. Determinants associated with increased surface contamination were the drug preparation and drug administration stages of the medication system as well as having more job categories responsible for drug transport. Up to 11 job categories per facility may have an exposure risk and the maximum dermal contamination levels for every job category exceeded the limit of detection. Factors associated with increased dermal contamination were working in acute care hospitals, female personnel, working as a porter, nurse, transport, unit clerk or other roles in the drug administration unit and having a duty to handle antineoplastic drugs. Urinary drug contamination of participants was higher than in non-hospital controls confirming that exposure is occurring in the workplace. Being a pharmacy receiver, pharmacy technician, porter, nurse, or unit clerk and a facility having more job categories responsible for drug transport were associated with increased urinary contamination. This is believed to be the first study examining environmental contamination and occupational exposure to antineoplastic drugs across the entire hospital medication system.

APA, Harvard, Vancouver, ISO, and other styles

16

Veeranki, Sreenivas P., Hadii M. Mamudu, Shimin Zheng, and James L. Anderson. "Common but Unknown! Extent and Determinants of Worldwide Youth Exposure to Secondhand Smoke." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/86.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Säterborg, Erik. "The Determinants of Hedging with Currency Derivatives : A quantitative study on the Swedish OMX Exchange." Thesis, Umeå universitet, Företagsekonomi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-119809.

Full text

Abstract:

Most firms are actively assessing the financial risks exposure and do determine a policy for the hedging activities. It is not solely the risk aversive attitude from the managers that need to be overlooked, but to provide sufficient information to the shareholder is desirable for minimizing the gap of information asymmetry, which is by itself considered a tool for value creation (Bergstrand et al. 2009:45-47). To narrow this gap, listed Swedish companies have since 2005 been required to disclose their financial risk in their Annual Reports. By using a quantitative approach the researcher will review the financial risk note in Annual Reports of 2008 to identify characteristics and determinant variables on firms depending on whether they utilize currency derivatives or not. An independent two-sample t-test has showed statistical significance that there difference of the means regarding size, FX exposure and leverage between users and non-users of currency derivatives. The means of currency derivatives users were higher for Size and FX exposure, while lower for leverage. A positive correlation between a firm’s size and FX exposure was found, suggesting that the determinant for hedging FX exposure could be explained by the size of the firm and vice versa.

APA, Harvard, Vancouver, ISO, and other styles

18

Gubbins, Eva J. "The role of nanomaterial-protein interactions in determining the toxic consequences of nanomaterial exposure." Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/3153.

Full text

Abstract:

As early biological responses to foreign objects in the body can be influenced by their bound proteins, the nanomaterial hard protein corona (the collection of slow exchange proteins that associate with nanomaterials) is an emerging area of interest in nanotoxicology. There is a limited but growing appreciation of the role these interactions have in influencing nanomaterial toxicity. This research dealt with (i) the characterisation of iron oxide and silica particles with and without a plasma, serum and lung lining fluid protein hard corona, (ii) the identification of the proteins in the hard corona that associate with the particles and (iii) the effect of the hard corona on influencing particle cytotoxicity in a J774.A1 macrophage cell line. Initial investigation of the particles illustrates the advantages in using a variety of characterisation techniques to better elucidate particle properties. Subsequent characterisation of the hard corona protein profile demonstrated a clear difference in the biological identity of the particles in a plasma, serum and in a lung lining fluid corona. Although it is difficult to associate the impact of any individual protein identified in the hard corona to cytotoxicity this study indicates that the binding of proteins plays a significant role in altering the cytotoxic potential (as determined by LDH release) in macrophages. The work also demonstrates the hard corona has an impact on macrophage chemotaxis, which further strengthens the hypothesis that the corona is a key consideration in nanoparticle toxicity. Ultimately this thesis finds that the nanomaterial hard corona is an important element to consider in experimental design and highlights the concept of creating particle preparation protocols to mimic the corona composition in vivo when examining in vitro cellular responses. This research highlights the implications for interpretation of data from in vitro cell culture tests that do not take the protein corona into consideration.

APA, Harvard, Vancouver, ISO, and other styles

19

Abu-Alhaija, Dania M. "The Development and Psychometric Testing of the Oncology Nurses Health Behaviors Determinants Scale." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin161710763068224.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Aldridge, Fiona Jane Psychology Faculty of Science UNSW. "The role of idealised image features in determining post-exposure body image and social comparisons." Publisher:University of New South Wales. Psychology, 2008. http://handle.unsw.edu.au/1959.4/41373.

Full text

Abstract:

This research examined the role that idealised image characteristics have in determining post-exposure body image and amount of self-reported social comparisons. This was tested by exposing female undergraduate students to media-portrayed idealised images that varied in their level of relevance, salience, or attainability. A negative impact of these images was indicated by greater post-exposure body dissatisfaction and body size estimation inaccuracy. In contrast, a positive impact was considered to have occurred when body dissatisfaction decreased and body size estimation was more accurate. If the images had a neutral impact on body image, one would expect little difference between groups or over time. A further aim was to determine whether a higher level of trait tendency to compare was related to more negative responding at post-exposure. In addition, thin ideal internalisation and restraint were examined as possible moderators. Studies 1, 2a, 2b, and 3 indicated that idealised image relevance and salience had little differential impact on post-exposure body image. That is, exposure to thin idealised images, irrespective of the salience and relevance manipulations, resulted in similar post-exposure body dissatisfaction and body size estimation. In contrast to this, the attainability of the image seemed to influence post-exposure responding, at least in terms of body size estimation (Study 4). Higher trait tendency to compare was associated with a greater amount of self-reported comparison with the images, but had little impact on body image. Surprisingly, these results were not moderated by thin ideal internalisation or restraint. The role of individual differences was explored with additional analyses in Study 5, which revealed that, when the power is sufficient, thin ideal internalisation, restraint, and self-reported comparisons with the images predicted post-exposure body dissatisfaction, but not body size estimation. Overall, this program of research suggests that idealised image features do not play a vital differential role in determining post-exposure body image, unless it is the body itself that is being manipulated. Results from this research support the idea that the mere presence of an idealised body is sufficient to activate negative responses, and there was little, if any, evidence for the occurrence of positive responses. These findings are discussed in terms of social comparison and schema theory, and in terms of their practical implications.

APA, Harvard, Vancouver, ISO, and other styles

21

Hugg, T. (Timo). "Exposure to environmental tobacco smoke, animals and pollen grains as determinants of atopic diseases and respiratory infections." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514291968.

Full text

Abstract:

Abstract Little is known about a) the differences in allergic and respiratory diseases between the Finnish and Russian populations, and the environmental factors associated with those differences, and b) exposure to pollen grains indoors and the efficiency of penetration of pollen from outdoor to indoor air. This thesis is based on a cross-sectional population-based epidemiological study conducted in Imatra (Finland) and Svetogorsk (Russia) in 2003 and a rotorod-type-sampler-based pollen study conducted in the province of South Karelia (Finland) between 2003 and 2004. The prevalence of allergic diseases was higher among Finnish than Russian schoolchildren. The symptoms among allergic children were more severe, and the occurrence of respiratory infections was in general more frequent in Russia than in Finland. In the logistic regression analyses the risk of asthma was particularly related to high maternal smoking exposure, and the risk of the common cold was related to high combined parental smoking during infancy (adjusted OR 1.83, 95% CI 1.06–3.17) in Finnish children. Among Russian children, allergic conjunctivitis was related to maternal smoking, while the common cold was inversely related to paternal and parental smoking (0.60, 0.37–0.98 and 0.31, 0.11–0.83, respectively) during the study period. The risk of asthma was inversely related to any indoor dog-keeping in Finland (0.35, 0.13–0.95), whereas in Russia the risk of asthma was increased in relation to combined indoor cat exposure during infancy and the study period (4.56, 1.10–18.91). The concentrations of pollen grains decreased from abundant (0–855 pollen grains per cubic meter, pg/m3) to low (0–3 pg/m3), when moving from outdoors to indoors and further. The differences in diseases and symptoms in these two closely related populations could be ascribed to differences in culture, exposures, diagnostic criteria and treatment. The concentrations of pollen in indoor air during the flowering period were mostly on a level high enough to cause reactions in only the most sensitive subjects. The results suggest that more efforts should be directed to reducing parental smoking, to studying the role and effects of nationally different animal exposures in childhood, and to assessing the importance of different penetration routes of pollen grains
Tiivistelmä Suomen ja Venäjän välisistä allergioiden ja hengitystietulehdusten esiintymiseroista ja esiintymiseen vaikuttavista ympäristötekijöistä tiedetään varsin vähän. Myös tutkimuksia siitepölyille altistumisesta sisätiloissa ja siitepölyjen tunkeutumiskyvystä ulkoilmasta sisäilmaan on niukasti. Tutkimus yhdistää sekä lääketieteellisen että luonnontieteellisen tutkimusalan tutkimustraditiot sekä atooppisten sairauksien ja/tai hengitystietulehdusten tärkeimpien määrittäjien tarkastelun yhdeksi tutkimuskokonaisuudeksi. Väestö- ja kyselylomakepohjainen poikkileikkaustutkimus toteutettiin Suomen ja Venäjän rajan molemmin puolin sijaitsevissa Imatran ja Svetogorskin kaupungeissa vuonna 2003. Tutkimusväestö koostui 512 suomalaisesta ja 581 venäläisestä 7–16-vuotiaasta koululaisesta (osallistumisaste 79 %). Rotorod-tyyppisen keräimen käyttöön perustuva siitepölytutkimus toteutettiin erilaisissa ulko- ja sisätiloissa Lappeenrannan ja Imatran kaupungeissa, Rautjärven kunnassa ja valtatie 6:lla vuosina 2003 ja 2004. Atooppisten sairauksien esiintyvyys oli runsaampaa suomalaisten koululaisten keskuudessa. Sitä vastoin allergisten lasten kokemat oireet olivat voimakkaampia ja hengitystietulehdusten esiintyvyys oli runsaampaa venäläisten koululaisten keskuudessa. Astmariski kytkeytyi erityisesti äidin runsaalle tupakoinnille altistumiseen raskauden (vakioitu OR 3.51, 95 % luottamusväli 1.00–12.3), ensimmäisen elinvuoden (3.34, 1.23–9.07) ja tutkimuksen aikana (3.27, 1.26–8.48). Nuhakuumeen riski oli suurentunut suomalaisten koululaisten keskuudessa, jotka olivat altistuneet molempien vanhempien runsaalle tupakoinnille ensimmäisen elinvuoden aikana (1.83, 1.06–3.17). Äidin tupakoinnille ensimmäisen elinvuoden (4.53, 1.49–13.8) ja tutkimuksen aikana (2.82, 1.07–7.44) altistuneilla venäläisillä oli suurentunut allergisen silmän sidekalvotulehduksen riski. Tutkimuksen aikainen isän ja vanhempien tupakointi vähensi nuhakuumeen riskiä (0.60, 0.37–0.98; 0.31, 0.11–0.83) Venäjällä. Suomessa koiranpito sisätiloissa vähensi astmariskiä (0.35, 0.13–0.95), vastaavasti Venäjällä raskauden jälkeinen sisätiloissa tapahtuva kissa-altistus lisäsi koululaisten astmariskiä (4.56, 1.10–18.91). Siitepölyjen pitoisuudet pienenivät siirryttäessä ulkoa (0–855 siitepölyhiukkasta ilmakuutiossa; sp/m3) sisätiloihin (0–17 sp/m3). Ympäristöaltisteisiin ja sairauden ennusteeseen vaikuttavat sekä kansallinen kulttuuri ja vakiintuneet tavat, että erot diagnosointikriteereissä, yleisessä tautitietoisuudessa ja lääkkeiden saatavuudessa. Näin ollen altisteiden voimakkuus ja kesto sekä terveysvaikutukset voivat vaihdella merkittävästi lähellä toisiaan sijaitsevien alueiden välillä. Siitepölypitoisuudet sisätiloissa olivat pääosin tasolla, jolle altistuminen aiheuttaa oireita vain kaikkein herkimmille allergisille. Tutkimuksen tulosten mukaan lisää voimavaroja tulisi suunnata passiiviselle tupakoinnille altistumisen vähentämiseen erityisesti yksilökehityksellisesti herkkien varhaisvaiheiden aikana, kansallisten eläinaltistuserojen terveysvaikutusten selvittämiseen sekä siitepölyjen erilaisten kulkeutumisreittien merkityksen tutkimiseen

APA, Harvard, Vancouver, ISO, and other styles

22

Quansah, Reginald. "Occupational determinants of adverse pregnancy outcomes : work in healthcare and exposure to welding fumes and metal dust." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/676/.

Full text

Abstract:

The goal of this thesis is to (i) systematically review all epidemiologic studies reporting on the relationship between occupational exposures and adverse pregnancy outcomes among nurses and physicians, (ii) compare the risk of adverse pregnancy outcomes between singleton newborns of nurses, midwives, and physicians and those of women in other occupations (reference groups) and (iii) investigate the risk of adverse pregnancy outcomes among parents exposed to welding fumes or metal dust. Data were obtained from all epidemiologic studies reporting on the relation between occupational exposures and adverse pregnancy outcomes among nurses and physicians, the 1990–2006 Finnish Medical Birth Register, and the Finnish Prenatal Environment and Health Study (FPEHS). Occupational exposure to anaesthetic gases was associated with spontaneous abortion and congenital malformation among nurses and physicians. Chemotherapy agents were associated with spontaneous abortion among nurses. There was moderate to substantial heterogeneity in the studied relations. In the FHCPS, singleton newborns of nurses have increased risk of low birth weight, post-term delivery, and small-for-gestational-age compared to those of teachers (reference group). Maternal employment as a midwife was not related to adverse pregnancy outcomes. The risk of high birth weight and post-term delivery were lower among singleton newborns of the physicians compared to those of other upper-level employees (reference group), but the risk of SGA and LGA did not differ between the newborns of physicians and those of the reference group. In the FPEHS, paternal exposure to welding fumes only was related to small-for-gestational-age. Maternal exposure to metal dust only was related to low birth weight and pre-term delivery and the joint effect of welding fumes and metal dust was related to small-for-gestational age. In conclusion, maternal employment as a nurses and parental occupational exposure to welding fumes or metal dust may increase the risk of adverse pregnancy outcomes.

APA, Harvard, Vancouver, ISO, and other styles

23

Nathell, Lennart. "Some determinants of sick leave for respiratory disease : occupation, asthma, obesity, smoking, and rehabilitation /." Stockholm, 2002. http://diss.kib.ki.se/2002/91-7349-301-5/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Nyström, Jennifer. "Determinants of serum perfluoroalkyl acid concentrations in Swedish adolescents and the importance of drinking water as a source of exposure." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385153.

Full text

Abstract:

The persistent and toxic perfluoroalkyl acids (PFAAs) are ubiquitously present in the environment and reach humans predominantly via food and drinking water. The aim of the present study was to investigate the effect of low-grade (<10 ng L-1 of single PFAAs) contaminated PFAAs drinking water on serum PFAA concentrations in a representative Swedish adolescent population, and to examine the influence of potential determinants on the variation of the PFAAs serum concentrations. This was done by using multivariate regression analysis on the possible determinants of blood serum PFAA concentrations in 479 Swedish adolescents, 10 to 21 years of age, who had left complete dietary and life style information in 2016-17 in the nation-wide food consumption survey Riksmaten Ungdom. Raw and drinking water samples (DW) from water treatment plants (WTPs) that delivered DW to participants schools were sampled in 2018, analysed for PFAAs, and used for assessing the participants DW PFAA exposure. Maternal education level and maternal birth country, consumption of fish, as well as age and sex were significantly associated with the participants PFAAs serum concentrations. DW concentrations as low as <1 ng L for PFOA and PFHxS, <0.45 ng L-1 for PFNA and <4 ng L-1 for PFOS were significantly associated with increased adolescent serum concentrations of the PFAAs in question, which suggests that low-grade contaminated drinking water is an important exposure route for Swedish adolescents. For risk assessment purposes, it was investigated whether parts of the adolescent population exceeded the serum PFOS and PFOA concentrations corresponding to the current health-based reference intakes as assessed by the European Food Safety Authority (EFSA) and the U.S. Agency for Toxic Substances and Disease Registry (ATSDR). Around 1.7% and 2.7% of participants had PFOS serum concentrations exceeding serum levels used to derive the tolerable daily intake (TDI) (EFSA) and the minimum risk level (MRL) (ATSDR), respectively and a cause for concern was consequently identified. However, the high serum concentrations of participants exceeding the TDI and MRL serum concentrations belong to participants suspected to have been previously exposed to highly contaminated drinking water and not from consuming foods and beverages containing background concentrations of PFAAs.

APA, Harvard, Vancouver, ISO, and other styles

25

Barnard, Alison M. "Determining the concentration of lead in MIT athletic facilities and estimating student-athlete exposure to lead." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/114364.

Full text

Abstract:

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 63-66).
In April of 2008, there were reports of elevated lead levels in several AstroTurf surfaced fields in New Jersey that motivated this investigation of MIT's synthetic turf field and other athletic facilities for elevated lead levels. I have analyzed samples of chalk, paint, dust, water, air, and synthetic turf fibers for lead concentration and isotopic composition by thermal ionization mass spectrometry. Additionally, blood lead levels were tested in a student-athlete and a non-athlete for control. The synthetic turf, water, chalk, and air analyzed from the athletic facilities were found to pose no significant lead hazard for student-athletes using the facilities, and the tested student-athlete had a normal blood lead level. The dust and paint did not pose a significant hazard to student athletes, but hazardous levels of lead were found in some dust and paint samples. It is recommended that further studies of the lead in duPont Gymnasium paint and Rockwell and duPont Gymnasium dust be performed and the potential hazards to be investigated.
by Alison M. Barnard.
S.B.

APA, Harvard, Vancouver, ISO, and other styles

26

CHAPMAN, DONALD RIVERS. "DETERMINING EMPLOYEE EXPOSURE TO ETHYLENE GLYCOL WHILE PERFORMING MAINTENANCE ON AN AIRCRAFT DEICING FLUID COLLECTION SYSTEM." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1187020385.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Parker, Benjamin. "Determining the relationship between inflammation, therapeutic exposure and cardiovascular risk in patients with systemic lupus erythematosus." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/determining-the-relationship-between-inflammation-therapeutic-exposure-and-cardiovascular-risk-in-patients-with-systemic-lupus-erythematosus(524e5d0f-f5fa-4750-b1bc-20f1c0cfa4d3).html.

Full text

Abstract:

Introduction: SLE is associated with pro-atherogenic metabolic derangement and an elevated cardiovascular risk. The vascular endothelium may be a key interface between active SLE and premature atherosclerosis. Improved understanding of the contribution of inflammation and its management to cardiovascular risk in SLE will inform personalised treatment decisions in SLE patients. Methods: Data from an international inception cohort was used to investigate the relationship between inflammatory disease activity, lupus phenotype and corticosteroid exposure and the metabolic syndrome (MetS) over 2 years in SLE patients. The relationship between disease activity (BILAG-2004) and markers of endothelial function (flow-mediated dilatation (FMD) of the brachial artery) and endothelial damage (endothelial microparticles (EMPs)) following a change in anti-inflammatory therapy was investigated in a longitudinal cohort of patients with active SLE. Results: MetS was common in young SLE patients (12.6-16.0%) over the initial 2 years of disease. Factors independently associated with developing MetS over the 2-year study period were (odds ratio (95% CI)) Hispanic ethnicity (3.47 (1.76, 6.86)), higher initial peak corticosteroid dose (1.02 (1.01,1.03)), and elevated anti-dsDNA antibodies at study entry (1.86(1.19,2.81)). MetS was often persistent and preceding MetS strongly predicted future MetS (4.83 (2.93, 7.87)). Patients with active SLE had reduced FMD (median (IQR) FMD 1.63% (-1.22, 5.32) vs. 5.40% (3.02, 8.57); p = 0.05) and elevated EMPs (157,548/ml (59,906, 272,643) vs. 41,025 (30,179, 98,082); p = 0.003) compared to age-matched controls. Both improved following a change in anti-inflammatory therapy, and correlated moderately with change in disease activity over time. Conclusions: Inflammatory disease activity and higher doses of corticosteroids in very early disease influence the development of MetS in SLE, which can become persistent. Endothelial dysfunction is common in patients with active SLE but can be improved with better disease control. Therefore even from disease onset, therapeutic regimes should be individually tailored to achieve good disease control whilst minimising corticosteroid doses, to improve cardiovascular risk surrogates in SLE.

APA, Harvard, Vancouver, ISO, and other styles

28

Ramnerö, Jonas. "Behavioral Treatments of Panic Disorder with Agoraphobia : Treatment Process and Determinants of Change." Doctoral thesis, Stockholm University, Department of Psychology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-404.

Full text

Abstract:

The present dissertation comprises four empirical studies within the area of behavioral treatment of panic disorder with agoraphobia. The focus is on studying issues pertaining to outcome, treatment process and determinants of change. The first study is a randomized controlled treatment study of 73 patients undergoing 16 sessions of either exposure in vivo (E), or cognitive behavior therapy (CBT). Both treatments showed clear improvements at post-treatment that were well maintained at 1-year follow up, and there were no significant differences between the treatments.

The second study concerned prediction of outcome in the same sample. From a variety of pre-treatment characteristics severity of avoidance was the one most related to outcome. Most predictors were found unrelated. Two approaches of prediction were also compared: treating outcome as a categorical vs. continuous variable. The different approaches yielded a somewhat dissimilar picture of the impact of pre-treatment severity of avoidance. The third study examined different aspects of the therapeutic relationship, and their relation to outcome. Clients’ perceptions of therapists and their ratings of the working alliance were generally not related to outcome at any point. On the other hand, therapists’ perceptions of patients as showing goal-direction and active participation were related to outcome from early on in therapy. The fourth study examined different aspects of change. It was found that change in indices of the frequency of panic attacks was not closely related to change in agoraphobic avoidance at post-treatment. Change in avoidance was also more related to other aspects of outcome. At one-year follow-up, a more unitary picture, regarding the different aspects of change was observed.

APA, Harvard, Vancouver, ISO, and other styles

29

Bradley, Katrina Diane. "Foreign exchange rates and corporate performance : a study of the nature, determinants, and management of economic currency exposure." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/22773.

Full text

Abstract:

In today's world of volatile currencies and increasing levels of cross-border trade, few companies, if any, are unaffected by movements in foreign exchange rates. This thesis investigates the impact of currency fluctuations on UK non-financial companies. In particular it focuses on their economic exposure, or the impact of unexpected changes in foreign exchange rats on the future cash flows of the firm. The empirical research presented in this thesis is based on two postal surveys that were distributed to the finance directors of listed UK non-financial companies (in 1996 and 1997) and also interviews conducted with some of the survey respondents. The aim of the research is to discover the direction, magnitude, and causes of the economic exposure faced by UK firms. This thesis takes as its primary focus the investigation of the indirect, or competitive determinants of economic exposure, in addition to the direct exposures arising from the volume of a company's cross-border trade. The study also reports on the extent to which the sample companies are able to make adjustments to their operating policies such as production location, input sourcing and pricing in order to reduce the sensitivity of their cash flows to foreign exchange rate movements. The principal conclusion of this thesis is that the cash flows of UK companies are less sensitive to changes in foreign exchange rates than the economic exposure theory would suggest. There are two explanations for this finding. The first is that many companies have achieved a natural hedge from currency fluctuations by purchasing a high proportion of their inputs in the foreign currencies they receive for their export sales. A second explanation is that some of the surveyed finance directors may not be aware of the full impact of foreign exchange rates on the competitive position of their companies. The survey evidence also suggests that the direct sources of economic exposure such as the extent to which a company sells in foreign markets are more significant than the indirect sources such as the geographical location of a company's competitors.

APA, Harvard, Vancouver, ISO, and other styles

30

Bigelow, Dyk Melinda Michelle. "Determinants of human exposure to Fipronil following use as a topical flea and tick treatment of companion animals." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=44&did=1905733921&SrchMode=1&sid=2&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270145414&clientId=48051.

Full text

Abstract:

Thesis (Ph. D.)--University of California, Riverside, 2009.
Includes abstract. Includes bibliographical references (leaves 201-210). Issued in print and online. Available via ProQuest Digital Dissertations.

APA, Harvard, Vancouver, ISO, and other styles

31

Forns, i. Guzman Joan 1981. "Social and environmental determinants of neuropsychological development from birth to preadolescence." Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/96193.

Full text

Abstract:

Introduction Neuropsychological development is a genetically guided process which is continuously modified by socio-environmental factors. This thesis aimed to study the main socio-environmental determinants of neuropsychological development in different time-periods, such in the first two years of life, during preschool, and during preadolescence. This thesis also aimed to summarize the work done in environmental epidemiology on neuropsychological development in a novel conceptual framework. Methods This thesis is based on the data of the INMA (Infancia y Medio Ambiente) Project. The main objective of this project is to evaluate the impact of environmental exposures in children’s health in 7 population-based birth cohorts in different regions of Spain. The neuropsychological development of approximate total of 2,650 children was assessed at different time-periods following the same protocols. Results (1) Maternal cognitive capacities were positively related with child cognitive development early in life in more disadvantaged occupational social classes. (2) The levels of child cortisol were not related to child neuropsychological development during the second year of life. (3) Higher levels of long-chain polyunsaturated fatty acids in colostrum due to prolonged periods of breastfeeding improved early neuropsychological development of children, in particular in those children exposed to maternal smoking during pregnancy. (4) Prenatal exposure to PCBs (specially for PCB congener 153) impacted negatively on psychomotor development during the second year in life and on general neuropsychological development at the age of 4 years. (5) Postnatal exposure to organochlorine compounds was associated with a delay in reaction time (speed processing) during the preadolescent period. (6) The conceptual framework proposed will improve the quality of research in this area. Conclusions Social and cultural determinants such as maternal intelligence, educational level or occupational social class, are configuring the proximal environment in which a child develops and determine their neuropsychological development. Current levels of some organochlorine compounds, particularly polychlorinated byphenils, measured in blood samples (from umbilical cord, mothers, or children) are impairing on neuropsychological development in the general population.
Introducció El desenvolupament neuropsicològic infantil és un procés guiat genèticament, el qual és contínuament influenciat per factors socials i ambientals. L’objectiu d’aquesta tesis fou l’estudi dels principals determinants socio-ambientals del desenvolupament neuropsicològic infantil en diferents períodes de temps. Aquesta tesis també té l’objectiu de resumir en un marc conceptual els diferents components del desenvolupament neuropsicològic pel seu ús en estudis d’epidemiologia ambiental. Mètodes Aquesta tesis està basada en dades del projecte INMA (Infancia y Medio Ambiente). El principal objectiu d’aquest projecte és avaluar l’impacte de les exposicions ambientals en la salud infantil en 7 cohorts de població establides en diferents regions d’Espanya. Dintre del marc d’aquest projecte, s’ha avaluat el desenvolupament neuropsicològic d’aproximadament 2.650 nens en diferents moments, seguint els mateixos protocols. Resultats (1) Les capacitats cognitives maternes estan positivament relacionades amb el desenvolupament cognitiu infantil en les primeres etapes, en les classes socials ocupacionals menys afavorides. (2) Els nivells de cortisol infantil no mostren associació amb el desenvolupament neuropsicològic durant el segon any de vida. (3) Nivells elevats d’àcids grassos poliinsaturats de cadena llarga en conjunció amb períodes prolongats de lactancia materna afavoreixen el desenvolupament neuropsicològic a les primeres etapes, especialment en aquells nens de mares fumadores durant l’embaràs. (4) L’exposició prenatal a PCBs (espcialment, al congener 153) impacta negativament en el desenvolupament psicomotor infantil durant el segon any de vida i en el desenvolupament neuropsicològic general als 4 anys d’edat. (5) L’exposició postnatal a compostos organocloroats està associada a una capacitat de reacció (velocitat de processament) més alentida en etapes preadolescents. (6) L’ús del marc conceptual propossat tesis afavorirà la qualitat de l’investigació en aquesta àrea. Conclussions Els determinants socials, com l’intel•ligència materna, el nivell educatiu o la classe social basada en l’ocupació, configuren l’entorn més proper del nen i determinen el seu desenvolupament neuropsicològic. Els nivells actuals de certs compostos organoclorats, especialment els bifenils policlorinats, mesurats en mostres de sang (de cordó umbilical, mares o nens) mostren efectes negatius sobre el desenvolupament neuropsicològic en la població general.
Introducción El desarrollo neuropsicológico infantil es un proceso guiado genéticamente, el cual está contínuamente influenciado por factores sociales y ambientales. El objetivo de esta tesis fue estudiar los principales determinantes socio-ambientales del desarrollo neuropsicológico infantil en diferentes periodos de tiempo. Esta tesis también tenía como objetivo resumir en un marco conceptual el trabajo hecho en epidemiología ambiental en el estudio del desarrollo neuropsicológico infantil. Métodos Esta tesis está basada en datos del proyecto INMA (Infancia y Medio Ambiente). El principal objetivo de esto proyecto es evaluar el impacto de las exposiciones ambientales en la salud infantil en 7 cohortes de población establecidas en diferentes regiones de España. El desarrollo neuropsicológico de aproximadamente 2.650 niños ha sido evaluado en diferentes momentos siguiendo los mismos protocolos. Resultados (1) Las capacidades cognitivas maternas están positivamente relacionadas con el desarrollo cognitivo infantil en edades tempranas en las clases sociales ocupacionales menos aventajadas. (2) Los niveles de cortisol en el niño no se asocian con el desarrollo neuropsicológico durante el segundo año de vida. (3) Niveles altos de ácidos grasos poliinsaturados de cadena larga debido a periodos largos de lactancia materna mejoraron el desarrollo neuropsicológico a edades tempranas, especialmente en esos niños cuyas madres fumaron durante el embarazo. (4) La exposición prenatal a PCBs (espcialmente para el congener 153) impacta negativamente en el desarrollo psicomotor durante el segundo año de vida y en desarrollo neuropsicológico general a la edad de 4 años. (5) La exposición postnatal a compuestos organoclorados está asociado con una peor capacidad de tiempo de reacción (velocidad de procesamiento) durante la preadolescencia. (6) El marco conceptual propuesto mejorará la calidad de la investigación en esta área. Conclusiones Los determinantes sociales tales como inteligencia maternal, nivel educativo o clase social basada en la ocupación, configuran el entorno más cercano en el cual el niño se desarrolla y determinan su desarrollo neuropsicológico. Los niveles actuales de ciertos compuestos organoclorados, especialmente los bifeniles policlorinados, medidos en sangre (de cordón umbilical, madre, o niño) tienen efectos negativos sobre el desarrollo neuropsicológico de la población general.

APA, Harvard, Vancouver, ISO, and other styles

32

Makhubele, Tinyiko Game. "Immune activation and cigarette smoke exposure as potential determinants of failure of haart in the setting of mother-to- child transmission." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/45938.

Full text

Abstract:

Persistent immune activation, even in the setting of virologically-suppressive HAART, is a hallmark of chronic immunodeficiency virus type (HIV-1) infection and a major force driving HIV-1 replication and progression to AIDS. Little is known about immune activation profiles and the effect of therapy in children infected with HIV-1 subtype C. The objectives of this study were to i) investigate and compare levels of circulating biomarkers of immune activation in a cohort of mothers (n=46) infected with HIV-1 subtype C relative to those of 20 healthy controls; ii) compare the biomarkers of immune activation between mothers and their HIV-infected children (n=46); iii) monitor the effects of virologically suppressive and non-suppressive HAART immune activation profiles in a subgroup of children (n=28) and iv) determine the effects of active smoking as well as maternal smoking on the biomarkers of immune activation in the mothers and their children, respectively. Multiplex bead array, ELISA and immunonephelometric procedures were used to measure plasma levels of the following biomarkers of immune activation: soluble CD14 (sCD14), beta 2 microglobulin (β2M), C-reactive protein (CRP), interferon gamma (IFNγ), monokine induced IFNγ, IFNγ-inducible protein 10 (IP10), tumour necrosis factor α (TNFα), macrophage inflammatory protein α and β (MIP-1α and β), transforming growth factor β (TGFβ), interleukin-1 receptor antagonist (IL-2 Ra), granulocyte- and granulocyte macrophage colony stimulating factors (G-CSF and GM-CSF), and several interleukins including IL-2, IL-4, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, and IL-17. Relative to the healthy control subjects, almost all of the circulating biomarkers of immune activation, including sCD14, β2M, CRP, MIG, IP10, IFNγ, TNFα,TGFβ and several of the interleukins and colony stimulating factors, were elevated in the HIV-infected mothers (P=0.0346-P<0.0001). The biomarker levels of the children were generally lower than those of the mothers with the exception of β2M which was significantly higher (P=0.001). Virologically suppressive HAART caused decreases in sCD14, β2M and MIG in a subgroup of the children (P=0.0286-P<0.0001) while sCD14 and MIG were increased in the treatment failure groups relative to the suppressed groups (P=0.0407-0.0002). An unexpectedly high number of mothers were smokers (21.7%); however no significant differences were observed between the non-smokers and smokers. In children exposed to maternal smoking, TGFβ levels were higher (P=0.0288). In conclusion, although somewhat lower than those of their mothers, HIV-infected children were found to have high levels of a range of circulating biomarkers of immune activation in the setting of higher viral loads. Successful HAART with virological suppression and increased levels of CD4+ T lymphocytes, was associated with significant decreases in some of the biomarkers, notably sCD14, beta 2 microglobulin and MIG, in children. Maternal smoking was associated with a significant increase in the concentration of immunosuppressive TGFβ in children, however further studies in larger groups are necessary.
Dissertation (MSc)--University of Pretoria, 2014.
tm2015
Immunology
MSc
Unrestricted

APA, Harvard, Vancouver, ISO, and other styles

33

Rusford, Emmanuel. "Factors determining exposure to benzene vapour among filling station attendants and road tanker drivers in the City of Cape Town, South Africa." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/9375.

Full text

Abstract:

Includes bibliographical references.
The aim of the study was to evaluate the occupational exposure to benzene amongst filling station attendants and road tanker drivers in the City of Cape Town and to determine factors associated with elevated benzene exposure levels.

APA, Harvard, Vancouver, ISO, and other styles

34

Brown, Shuné. "Determining the exposure to and skills needed by Industrial – Organisational Psychologists in the Western Cape Province to counsel employees towards flourishing in the workplace." University of Western Cape, 2019. http://hdl.handle.net/11394/7420.

Full text

Abstract:

Magister Commercii (Industrial Psychology) - MCom(IPS)
According to literature, Industrial-Organisational psychology is mainly concerned with investigating the behaviour of humans within the work environment. It is stated that Industrial-Organisational psychology deals with well-adjusted working adults to improve well-being and efficiency by applying psychology principles (Health Professions Act, 2011). One of the roles of the Industrial-Organisational psychologist is to provide counselling in the workplace.

APA, Harvard, Vancouver, ISO, and other styles

35

Adamopoulos, Dionysios. "Environmental determinants of arterial stiffness and wave reflection: pathophysiological mechanisms and clinical implications." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209744.

Full text

Abstract:

Introduction – Objectives. The cardiovascular system is in direct and constant interaction with its environment. Exposure to various environmental parameters, such as low temperature, air pollution and tobacco smoke, has been strongly associated with serious or even fatal cardiovascular outcomes. Arterial stiffening and greater wave reflection are age-related vascular modifications that lead to an increased risk of cardiovascular events. The aim of this work was to explore the relationship between selected environmental factors and arterial elastic properties in an effort to elucidate the underlying mechanisms that link these factors to increased cardiovascular mortality.

Study 1: Effects of cold exposure on central and peripheral vascular tone. Our first study explored the effects of cold exposure on aortic stiffness and peripheral microvascular tone. We observed that cold exposure, in addition to its chronotropic effects, provoked an increase in aortic stiffness, as assessed by aortic pulse wave velocity, as well as significant vasoconstriction of peripheral arterioles in the microcirculation. Moreover, we explored the magnitude of this effect in a different population (Black subjects of African origin), which is traditionally characterized by exaggerated reactions to adrenergic stimuli. We noted that the vascular reactions, in terms of both aortic stiffness and microvascular vasoconstriction, were more profound in Black Africans than in age-matched Caucasian-Whites. These results argue for a direct effect of cold exposure on arterial stiffness and peripheral vascular tone, probably through activation of the orthosympathetic system.

Study 2: Exposure to ambient particulate matter and arterial stiffness. We explored the effects of acute exposure to outdoor particulate matter on aortic stiffness and aortic wave reflection. We studied the relationship between central hemodynamic parameters and ambient concentration of particulate matter in a population of patients who attended the Hypertension Clinics of Athens University. After statistical correction for a number of potential confounders, we did not observe an association between ambient concentrations of particulate matter and aortic stiffness. However, in men, particulate matter concentration was related to the amplitude of the reflected wave reaching the aorta from the periphery. These results suggest a direct acute interaction between particulate matter concentration and vascular tone, leading to an enhanced arterial wave reflection.

Study 3: The role of nicotine on the vascular effects of environmental tobacco smoke. Environmental tobacco smoke is considered as the most important source of particulate matter in the indoor environment. We recently demonstrated that exposure to tobacco smoke augmented wave reflection, an effect that was not seen after equivalent exposure to the smoke of non-tobacco, herbal cigarettes. We also noticed that the increased wave reflection was proportional to the plasma concentrations of nicotine. However, a direct causal effect between nicotine, arterial wave reflection and aortic stiffness has never been clearly demonstrated. We observed that increasing nicotine plasma concentration to levels comparable to those seen after extensive exposure to environmental tobacco smoke, provoked an increase in both aortic stiffness and arterial wave reflection after correction for heart rate and blood pressure changes. These results confirm the significant participation of nicotine in the vascular effects of passive smoking.

Conclusions. Globally, our results reveal the deleterious effects of cold, particulate matter exposure, and nicotinic stimulation on arterial stiffness, peripheral microcirculation and aortic wave reflection. The hemodynamic modifications associated with these effects may at least partially explain the causal relation between cold exposure, ambient air pollution and cardiovascular mortality.

Introduction-Objectifs. Le système cardiovasculaire est en relation directe et constante avec l’environnement. L’exposition au froid, la pollution atmosphérique et le tabagisme passif sont associés à des événements cardiovasculaires aigus graves et même fatals. La rigidification des artères et l’intensification de la réflexion de l’onde de pouls au niveau de l’aorte accompagnent le vieillissement et prédisent un risque cardiovasculaire accru. Nous avons testés l’hypothèse que les effets cardiovasculaires délétères des facteurs environnementaux comportent une altération des propriétés élastiques artérielles. Ceci pourrait être un des mécanismes physiopathologiques qui lie la mortalité cardiovasculaire aux variables environnementales.

Étude 1 :Exposition au froid ;effets centraux et périphériques. Notre première étude portait sur l’effet de l’exposition au froid sur la rigidité aortique et le tonus vasculaire des artérioles périphériques. Nous avons démontré que l’exposition au froid, hormis ses effets chronotropes, provoquait une augmentation de la rigidité artérielle – mesuré par la vitesse de l’onde de pouls au niveau de l’aorte - ainsi qu’une vasoconstriction importante au niveau des artérioles de la microcirculation. Nous avons ensuite déterminé l’amplitude de cet effet dans une autre population (sujets Africains-Noirs) qui se caractérise par des réactions plus prononcées aux différentes stimulations adrénergiques. Nous avons observé que les réactions vasculaires, tant au niveau de la rigidité aortique qu’au niveau de la microcirculation, étaient plus marquées chez les Africains-Noirs que chez les Caucasiens. Ces résultats révèlent un effet délétère de l’exposition au froid sur la rigidité aortique et le tonus vasculaire des artères périphériques, probablement via une activation du système orthosympathique.

Étude 2 :Exposition aux microparticules atmosphériques et rigidité artérielle. Nous avons ensuite investigué les effets de la pollution atmosphérique sur la rigidité artérielle et la réflexion de l’onde de pouls vers l’aorte. Nous avons étudié la relation entre les paramètres hémodynamiques centraux et la concentration atmosphérique de microparticules dans une population de patients qui ont consulté la Clinique Universitaire d’Hypertension Artérielle d’Athènes. Après correction statistique pour les facteurs confondants, nous n’avons pas observé de corrélation entre la rigidité artérielle et le taux de microparticules atmosphériques dans l’ensemble de la population investiguée. Par contre, si on restreint l’analyse aux résultats obtenus chez les sujets masculins, on s’aperçoit que la concentration atmosphérique de microparticules était associée de façon significative avec l’amplitude de l’onde réfléchie par la périphérie vers l’aorte et la pression pulsée aortique. Ces résultants suggèrent un effet direct des microparticules au niveau de la microcirculation. L’augmentation de l’amplitude de l’onde réfléchie consécutive à une vasoconstriction périphérique, modifie vraisemblablement les pressions au niveau de l’aorte chez le sujet masculin lors de pics de pollution.

Etude 3 :Le rôle de la nicotine dans les effets vasculaires du tabagisme passif. Le tabagisme passif est considéré comme la source la plus importante d’émission de microparticules au niveau domestique. Cependant, la composition chimique des particules semble jouer un rôle essentiel sur les ondes de réflexion. Nous avons démontré récemment que l’exposition passive à la fumée des cigarettes du tabac augmente l’intensité de la réflexion de l’onde de pouls. Ceci n’a pas été observé avec l’exposition à la fumée des cigarettes non tabagiques, en dépit d’une concentration ambiante tout à fait comparable de microparticules. Par ailleurs, nous avons observé que l’augmentation de l’incidence de l’onde de pouls au niveau de l’aorte était fortement associée à la concentration plasmatique de la nicotine. Un lien causal entre la nicotine, réflexion de l’onde de pouls et rigidité artérielle n’avait jamais clairement été établi. Nous avons testé cette hypothèse en administrant la nicotine pure chez des sujets sains. Nous avons observé que l’augmentation des taux plasmatiques de la nicotine à des valeurs comparables à celles qui surviennent après une exposition intensive au tabagisme passif, intensifiait la réflexion de l’onde de pouls et augmentait la rigidité artérielle. La correction statistique pour l’augmentation de la fréquence cardiaque et l’augmentation de la pression artérielle en réponse à la nicotine ne modifiait pas ces conclusions. Nos résultats démontrent ainsi les effets cardiovasculaires importants de faibles concentrations de nicotine, similaires à ceux qui sont atteints en cas d’exposition à un tabagisme passif.

Conclusions. Nos résultats révèlent les effets néfastes de l’exposition au froid et aux microparticules atmosphériques sur la rigidité artérielle, la microcirculation périphérique et la réflexion de l’onde de pouls. Nous avons pu également démontrer le rôle de la stimulation nicotinique dans les effets vasculaires aigus du tabagisme passif, comme en témoigne l’augmentation de la réflexion de l’onde de pouls au niveau aortique. Ces modifications hémodynamiques favorisent l’ischémie myocardique, et constituent un des mécanismes par lesquels l’exposition au froid et à la pollution atmosphérique favorisent la pathologie cardiovasculaire.

Doctorat en Sciences médicales
info:eu-repo/semantics/nonPublished

APA, Harvard, Vancouver, ISO, and other styles

36

Cervellati, Linda. "Determinants of Particulate Matter and Soot levels on the transport network of The Rotterdam-The Hague Metropolitan Region and evaluation of cyclists’ exposure among the different cycling infrastructure types." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

Find full text

Abstract:

In the past twenty years, considerable progress has been made to improve urban and sub-urban air quality in The Netherlands as well as in all the others European countries. However, the industrial development, the constitution of increasingly large urban areas, the use of heating sources, the increase in the emission of combustion products and many other factors still contribute considerably to the deterioration of the air quality. Recently, more and more studies about the impact of air pollution in The Netherlands focused on the category of cyclists, for both their great number due to the increasingly promotion of cycling as a mode of transportation in this country and for their direct contact with the air pollutants. It is indeed well known that, despite bicycling in urban areas has beneficial effects on people's health and well-being, it may be associated with health and safety risks due to potentially high levels of exposure to air pollution especially during the morning and evening commute. This study has three main aims. The first one is that of investigate, through the Linear Regression Analysis, which factors have the highest impact on the levels of concentrations of three air pollutants, PM2.5, PM10 and soot, in The Rotterdam – The Hague Metropolitan region. The second goal consists in having an assessment of how much the cyclists are exposed to these air pollutants in the three different main types of cycling infrastructures located in this area: road space shared with motor vehicles, separated lane for them (cycle lane marked on the road), and cycle lane (solitary bike path or lane separated by a physical barrier). Moreover, this section consists also in estimating how many people are impacted by the highest levels of air pollution exposition in the city of Rotterdam. Finally, the last objective focuses on the prediction of the average yearly levels of air pollution for six specific bike routes chose in Rotterdam.

APA, Harvard, Vancouver, ISO, and other styles

37

Fößel, Judith [Verfasser], Gottfried [Akademischer Betreuer] Spangler, and Gottfried [Gutachter] Spangler. "Parenting and Temperament in the Context of Risk: An Investigation of Determinants of Inter- and Intraindividual Differences in Parenting Behavior and Temperament Development under Risk Exposure / Judith Fößel ; Gutachter: Gottfried Spangler ; Betreuer: Gottfried Spangler." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2019. http://d-nb.info/119325275X/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Trask, Catherine, Mieke Koehoorn, Judy Village, Kay Teschke, and Peter W. Johnson. "Modeling determinants of working exposures and exposure variability." 2006. http://hdl.handle.net/2429/837.

Full text

Abstract:

Work-related back injuries represent 25% of workplace injuries in British Columbia, and more than a quarter of all back strain claims are from employees in five high-risk industries: forestry, wood and paper products, construction, transportation, and warehousing. Epidemiological studies require data on physical exposures to risk factors from large numbers of individuals in order to observe exposure-response relationships and for the results to be representative and generalizable. Unfortunately, there is a tradeoff between precision and expense, with the most precise measurement methods being too expensive to use in large epidemiological studies. The overall goal of this study is to identify a suite of measurements that afford both precision and cost efficiency for large scale work-site studies of numerous physical exposures across diverse settings and occupations.

APA, Harvard, Vancouver, ISO, and other styles

39

Lee, Cheng-An, and 李正安. "Exchange Exposure and the Determinants of Exchange Exposure." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/58474669419402556514.

Full text

Abstract:

碩士
逢甲大學
企業管理學系
87
Based on increasing of international trade, Taiwan Exchange Market has become more and more international and free. Exchange rate fluctuations have a substantial impact on the profitability of industries in Taiwan. This study intends to examine industry-level and company-level exchange rate exposure by using regression model which is always used when measure exchange exposure. The sample is divided into two approximately equal subperiodes to measure exchange exposure. This study finds that for the period form January 1986 to December 1995, there is significant exposure on domestic firms and their influence directions are different. Contrary to other research findings, we find little evidence that lagged exchange rate changes have explanatory power. Finally, this study attempts to identify determinates of firm exposure. The evidence is consistent with optimal hedging theory. The results indicate that large firms and firms with higher export ratio tend to have lower exposure to exchange rate risk。 Taiwan is a small and open economic environment；scale of industry is smaller relatively. In compare with foreign industries, the impacts of exchange rate change on profitability of domestic industries are more significant, and them on firms and industries with unique characteristics is also different.

APA, Harvard, Vancouver, ISO, and other styles

40

Chang, Chuan-Yi, and 張全毅. "Determinants of foreign exchange exposure and Asymmetric foreign exchange exposure." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/17904627954932401198.

Full text

Abstract:

碩士
國立成功大學
國際企業研究所碩博士班
94
Abstract The effect of exchange rate movements on the value of a firm has become an important field in both academic research and practical investment analysis. In this paper, we try to answer two questions in this field: (1) what are important factors in determining of foreign exchange exposure? (2) Is the firm value influenced by foreign exchange rate asymmetrically? Previous empirical results focus on firm’s level of foreign involvement, namely export ratio or foreign sales, and using currency derivatives. However, they ignored that firms’ different foreign entry mode might be an important in determining of foreign exchange exposure, too. Thus, we focus on this part to shed more light on the determinants of foreign exposure. Based on firms’ specific behaviors, namely asymmetric pricing-to-market behavior, hysteretic behavior and hedging behavior, we could find some evidences of asymmetric foreign exchange exposure. This result might explain why we cannot detect the significant linear foreign exposure. Our empirical results show that firms’ foreign entry mode indeed an important factor in determining of exposures. Firms adopt joint venture mode as foreign entry strategy could significantly reduce the foreign exchange exposure. It is evidence that firms yield asymmetric foreign exchange exposure in Taiwan market, especially in year 1999 and 2001. We also find that firms with higher export ratio and more foreign countries where invested in have a higher possibility to yield asymmetric exposures.

APA, Harvard, Vancouver, ISO, and other styles

41

Hsieh, Shu-Fan, and 謝舒帆. "Exchange rate exposure and determinants of exposure in Taiwan electronic industry." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/86371086626909606748.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Chien-Jung, Wu, and 吳健榮. "Exchange rate exposure and determinants of exposure in Taiwan electronic industry." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/20743284932255374775.

Full text

Abstract:

碩士
中國文化大學
國際貿易學系碩士班
92
This study uses 83 companies of Taiwan electronic industry as our samples. A re-gression analysis was used to test the degree of exchange rate exposure and weather the exchange rate risk has lag effect in Taiwan electronic industry. Moreover, we also use regression analysis to test the effects of export ratio, stock pledge ratio, debt ratio, firm’s size and research and development ratio on foreign exchange ratio and see weather all of them are the determents of foreign exchange exposure. The empirical results show that our test about the degree of exchange rate exposure in Taiwan electronic industry is not significant. This result is as the same as the em-pirical test of Jorion (1990)、Amihud (1994)、Bartov and Bodnar (1994). However, we will test weather the exchange rate risk has lag effect in Taiwan elec-tronic industry. The empirical results show that it exists lag effect between the firm’s value and exchange rate exposure. The result implies that there may be inefficient in Taiwan investment market. When it mentions to the determents of exposure, debt ratio and firm’s size were significantly related with exposure, however, export ratio, stock pledge ratio, research and development ratio weren’t significantly related with exposure.

APA, Harvard, Vancouver, ISO, and other styles

43

Lai, Pao-Yueh, and 賴寶月. "EXCHANGE RATE EXPOSURE AND DETERMINANTS OF EXPOSURE IN TAIWAN STEEL INDUSTRY." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/24468791975226259138.

Full text

Abstract:

碩士
大同大學
事業經營學系(所)
92
This research studied 33 Taiwan steel companies approved by Security and Futures Commission to be listed in TSEC & OTC, over the 2000-2003 period, probe into the exchange rate exposure of Steel Corporation. Analysis procedure was divided into four steps, first, used a two-factor model engaging in the relationship between contemporaneous exchange-rate fluctuations and stock returns. Next, all variables are adjusted. Taking into account the hedging activities that some companies take to hedge the determinants of expected exchange rate fluctuation, this study puts the variable of unpredictable exchange rate into the regression model in hopes of getting a better picture of exchange rate exposure. Third step a test is done to check whether there is a significantly lagged effect in exchange rate exposure of steel industry in Taiwan. Finally, use cross-sectional data to investigate into determinants of exchange rate exposure, Then employ corporate size, debt ratio, current ratio, the times interest earned ratio and the book-to-market ratio, conduct a multi-regression analysis of five proxy variables on individual corporate coefficient of exchange rate risks. The empirical findings of this research are as follows: 一、Estimate of Exchange Rate Exposure: 1. Among 33 TSEC & OTC listed steel companies in Taiwan, 12.1% of them showed significance in contemporary exchange rate exposure, and their values were all positive. 2. Adjusted the variable of exchange rate fluctuation by using exponential smoothing technique the significant rate only increases from 12.1% to 15.15%. 3. The lagged exchange rate exposure of Taiwan steel industry isn't as significant as contemporary exchange rate exposure, only 2 companies reach the level of significance, or 6%, and with positive value. However, the lagged exchange rate exposure is less significant than the contemporary exchange rate exposure. So the next analysis is based on contemporary exchange rate exposure. 二、 Determinants of Exchange Rate Exposure: Among determinants of influencing exchange rate exposure of steel industry, debt ratio and the times interest earned ratio, which are belonging to hedging motivations of companies, are both significant. It means when having a bigger debt ratio (or smaller times interest earned ratio) a company has higher odds of facing financial distress. In order to reduce bankruptcy cost and agency cost, companies will aggressively take hedging activities, and thus lower their exposure to exchange rate movements. The bigger company size has the more significant of the exchange rate exposure. The beta coefficient of current ratio and book-to-market ratio all show a negative relationship to exchange rate exposure. Nevertheless, all the beta coefficients don't reach the significant level, and thus there's no statistic meaning inside.

APA, Harvard, Vancouver, ISO, and other styles

44

Lin, Ya-Chien, and 林亞倩. "EXCHANGE RATE EXPOSURE AND DETERMINANTS OF EXPOSURE IN TAIWAN TEXTILE INDUSTRY." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/89956745884702610747.

Full text

Abstract:

碩士
銘傳大學
國際企業學系碩士在職專班
94
EXCHANGE RATE EXPOSURE AND DETERMINANTS OF EXPOSURE IN TAIWAN TEXTILE INDUSTRY Student: Ya-Chien Ling Advisor: Tzu-Ping Ho Ph.D Abstract This research studied 32 Taiwan textile industries to be listed in TSEC, over the 1996-2004 periods, probe into the exchange rate exposure of Textile Corporation. Analysis procedure was divided into three steps. First, we used a two-factor regressing model engaging in the relationship between contemporaneous exchange rate exposure and stock returns. Secondly, we investigated whether exchange rate exposure is asymmetric for sign asymmetry and magnitude asymmetry. Finally, we investigated into determinants of exchange rate exposure, used firm’s size、 export ratio、 long-term liabilities ratio and the foreign capital investment ratio of four proxy variables on individual corporate coefficient of exchange rate risks.　The empirical findings of this research are as follows：一、Estimate of Exchange Rate Exposure： Most Taiwan textile industries showed significance in contemporary exchange rate exposure. 二、Asymmetric exchange rate exposure： 1.The Taiwan textile industry had an influence on magnitude asymmetries of exchange rate exposure of stock returns. 2.We observed that the significance of exposure coefficients deteriorates drastically when asymmetries were taken into account. One possible interpretation is that the negligence of multiple asymmetries may overestimate exchange rate exposure. 3.Most enterprises showed significantly negative exposure effects, probably in order to lag effect, hot money, importing cost, the J curve effect and competing result etc. 三、Determinants of Foreign Exchange Rate Exposure： Only firm’s size was significantly related with exposure, the coefficient sign direction was negative. However, export ratio、 long-term liabilities ratio and the foreign capital investment ratio weren’t significantly related with exposure. Key Words ： Foreign Exchange Exposure、Asymmetry、Firm’s size

APA, Harvard, Vancouver, ISO, and other styles

45

Chang, Hing-Ju, and 張杏如. "EXCHANGE RATE EXPOSURE AND DETERMINANTS OF EXPOSURE IN TAIWAN ELECTRONIC INDUSTRY." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23311957955434914668.

Full text

Abstract:

碩士
銘傳大學
國際企業學系碩士在職專班
98
In this global international environment, Taiwan’s electronic industry have been investing and trading globally. Currency exchange fluctuation becomes a major risk and influencing factor in companies’ operational earning. Therefore, this theses will study the foreign exchange exposure risk among the listed companies in electronic industry. Using data from the 97 listed electronic companies in Taiwan during 1999 to 2009 as sample base, this study will go over three major areas: 1. how does currency fluctuation affects Taiwan’s listed electronic companies’ operational earning? 2. Asymmetric foreign exchange exposure study. 3. Factors affecting foreign exchange exposure. 一、 Currency exchange fluctuation is a significant influencing factor on individual company’s stock price performance. 二、 Taiwan listed electronic companies can have asymmetric exchange exposure due to fluctuation in currency exchange. Without factoring this, study can underestimate the foreign exchange exposure of Taiwan’s electronic industry. 三、 Determining factors for the Taiwan electronic companies’ foreign exchange exposure. 1.Looking at the companies’financial, only long term liability shows positive correlation to the foreign exchange exposure. Export percentage, company’s size and foreign capital investment are not significant coorelated to the foreign exchange exposure. 2.The use of financial derivatives products do correlate positively with the foreign exchange exposure. 3.Company’s strategic resources and capabilities, including foreign direct investment, diversification, Vertical integration, and product differentiation does not always translate into lower foreign exchange exposure for the individual company.

APA, Harvard, Vancouver, ISO, and other styles

46

Chen, Chin-Hung, and 陳勁宏. "The Determinants of Foreign Exchange Rate Exposure." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/77678310990834050782.

Full text

Abstract:

碩士
國立暨南國際大學
國際企業學系
98
From the breakdown of Bretton Woods system, many researchers begun to study the relationship between foreign exchange rate and firm’s returns. They used foreign currency per US dollar or exchange rate of country trade-weighted to examine exchange rate exposure for individual firm and industries. Unfortunately, the results of most studies were insignificant. Due to the results were insignificant, studies started to realize what reasons for the insignificant results were. Some of studies thought that the return of individual firm was not only affected by foreign exchange rate, but also by other microeconomic effects. Besides, other studies indicate that legged effect, asymmetric effect and the use of financial tool also affect exchange rate exposure be met with limited success. Moreover, passed studies further discuss that the determinants of exchange rate exposure such as the ratio of foreign sales, firm size, speed ratio and leverage etc. They found the positive relationship between the exchange rate exposure of firm value and the ratio of foreign sales or between the exchange rate exposure of firm value and leverage. There was a negative relationship between the exchange rate exposure of firm value and firm size. This paper develops a model of firm valuation to examine exchange rate exposure of 202 Taiwan firms during 1999-2005. In contrast to previous studies, we find that exchange rate fluctuations do affect firm value. More specifically, we find that higher significant exchange rate exposure by using the exchange rate of firm trade-weighted to examine than foreign currency per US dollar or exchange rate of country trade-weighted.

APA, Harvard, Vancouver, ISO, and other styles

47

Burstyn, Igor. "Determinants of flour dust exposure in bakeries." Thesis, 1996. http://hdl.handle.net/2429/4722.

Full text

Abstract:

This thesis presents the results of an investigation into factors that are associated with flour dust exposures in B.C. bakeries. We describe observed exposure levels and advise on control measures which may reduce an individual's exposure to flour dust. In this investigation, flour dust exposure was assesed using three measures: inhalable dust, wheat antigen and fungal a-amylase. Inhalable dust was measured gravimetrically. The wheat antigen and a-amylase content of the water soluble fraction of inhalable dust was assayed via ELISA. Ninety-six bakery workers, employed in seven different bakeries, participated in the investigation. Two side-by-side full-shift inhalable dust samples were obtained from each study participant on a single occasion. We were able to obtain useable exposure measurements for all three exposure measures from each study participant. During sampling, information on potential determinants of exposure was collected. It was used in analysis of variance and multiple regression to identify significant predictors of exposure (determinants). The exposure levels observed in this study indicated that the bakery workers were subject to a mean inhalable dust exposure of 8.2 mg/m3 (ranging from 0.1 to 110 mg/m3), a mean a-amylase exposure of 22.0 ng/m3 (ranging from below limit of detection of 0.1 to 307.1 ng/m3) and a mean wheat antigen exposure of 109 ug/m3 (ranging from below limit of detection of 1 to 1018 ug/m3). Seventeen percent of the measured inhalable dust exposures exceeded the regulatory exposure limit of 10 mg/m3. Some wheat antigen and a-amylase exposures showed levels capable of causing respiratory symptoms. Regression, models which explained 74 to 79% of variability in inhalable dust, a-amylase and wheat antigen exposures were constructed. According to the models, tasks such as weighing, pouring and operating dough forming machinery increased flour dust exposure, while fully automated forming, packing, catching and decorating decreased exposure. Bread, bun and puff pastry production lines were associated with increased exposure, while cake production was associated with decreased exposures. We describe a novel method of controlling the exposures in bakeries via the substitution of dusting with the use of the divider oil, and discuss which pieces of equipment appear to be associated with elevated exposures.

APA, Harvard, Vancouver, ISO, and other styles

48

PAI, CHIH-HUI, and 白智慧. "Exchange Rate Exposure and Determinants of Exposure in Taiwan Semiconductor, Steel and Plastics Industry." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/2s5nez.

Full text

Abstract:

碩士
銘傳大學
國際企業學系碩士在職專班
104
This study takes 43 listed semiconductor companies, 27 listed steel companies and 18 listed plastics companies as sample and uses a regression analysis to estimate the degree of exchange rate exposure. Moreover ,we also use regression analysis to test the effects of firm’s size, export ratio, quick ratio and debt ratio on foreign exchange ratio and see weather all of them are the determinants of foreign exchange exposure. The monthly data from January 2006 to December 2014 and separated two periods by the Financial Tsunami of 2008. The empirical results show that the degree of exchange rate exposure in Taiwan plastics and steel industry is not significant. On the contrary, the semiconductor industry have significant exchange rate exposure, and the results indicate that a appreciating Taiwan dollars have a favorable impact on firm’s returns. For the determinants of foreign exchange exposure, the result of the research indicates that before the financial tsunami, export ratio has negative impact on exchange rate exposure in the semiconductor industry, after the financial tsunami, the semiconductor industry with higher export ratio and smaller size may have lower exchange rate exposure. The export ratio, quick ratio and debt ratio have negative impact on exchange rate exposure in the steel industry before the financial tsunami, after the financial tsunami, all of them become insignificant. Before the financial tsunami, debt ratio has positive impact on exchange rate exposure in the plastics industry, after the financial tsunami, export ratio has negative impact on exchange rate exposure in the plastics industry.

APA, Harvard, Vancouver, ISO, and other styles

49

"Modeling the relation of hand-arm vibration exposure and occupation characteristics using occupational health and safety administrative data." Thesis, 2014. http://hdl.handle.net/10388/ETD-2014-11-1836.

Full text

Abstract:

Background Hand-arm vibration (HAV) is an occupational hazard which, cumulatively, leads to hand-arm vibration syndrome (HAVS). Detection and reduction of HAV can help prevent the disease or slow down its progress. Unfortunately, assessment of HAV through direct measurement is difficult due to the high cost of measurement equipment, interruption of work performance, and long travel cost to worksites. An alternative assessment method is through development of an exposure prediction model to identify workplace, tool, and task characteristics which significantly predict HAV exposure. Purpose The purpose of this study is twofold: 1) to determine the extent and nature of previously published scientific journal articles on exposure prediction modeling of HAV through performing a systematic review; and 2) to develop a new exposure prediction model using administrative data to find significant HAV predictors. Methods A systematic review of relevant studies involved humans aged 18 or over, applicable to occupational setting, with vibration measured using tri-axial accelerometer and statistical modeling of the effects of occupational characteristics on measure HAV were identified. Five online bibliographic databases (Medline, CINAHL, Web of Science, Scopus, and EMBASE) were searched using a combined word list of terms under three categories: “occupational diseases”; “Hand-arm vibration”; and “Statistical Modelling”. Two multiple linear regression models predicting average hand-arm vibration exposure over 8 hour day, A(8), were built using enforcement data collected by Ministry of Labour Relations and Workplace Safety Saskatchewan using standard model building method. In addition, GEE was used to account for repeated data collection within workers and worksites. Results In the first manuscript, 7 articles found were deemed relevant. Four studies built regression models, while three used ANOVA to find significant HAV predictors. Examples of significant HAV predictors included: tool age, tool weight, participant, and operating power; the proportion of HAV variance explained varied from 46 to 90%. In the second manuscript, the models based on administrative data explained 16% to 27% of A(8) variance. The included variables were tool power source, vibration control, and job type for the parsimonious model; the comprehensive model has the same variables as parsimonious along with accelerometer attachment method and tool brand. Conclusion HAV prediction through exposure prediction modeling is a relatively new method for assessing occupational HAV. It is feasible to find HAV predictors using low-cost administrative data, and variables such as tool power source, job type, and vibration control make promising predictors. However, the variance explained will be lower than using data collected for research purposes. The significant predictors found in the systematic review can be considered when installing protective measures in the future. The significant predictors found and procedures used from the modeling study can be considered for future HAV exposure prediction modeling studies.

APA, Harvard, Vancouver, ISO, and other styles

50

Ross, Andrew Spilsbury. "Determinants of exposure to metalworking fluid in small machine shops." Thesis, 1999. http://hdl.handle.net/2429/10340.

Full text

Abstract:

The objectives of this study were to measure personal airborne concentrations of metalworking fluids (MWF) in small machine shops by three different methods and to conduct a determinants of exposure analysis to evaluate factors that contribute to or minimize exposure to MWF. The three aerosol exposure measures were "total" aerosol, PM10 aerosol and extractable mass concentration. Eighty-eight machinists, employed at fifteen different machine shops, participated in the study. Side by side full shift "total" and thoracic aerosol samples were obtained from all participants and seventy-three machinists were sampled on two occasions with a minimum of eight days between measurements. There was total of 161 person-days of participation. Machinists were observed for their entire shift and information was collected at 15-minute intervals on different tasks they performed. Shop, machine tool and MWF management characteristics were also collected. Statistical modeling of the collected information was used to identify significant predictors of exposure. Extractable mass concentration was analyzed using a provisional American Society for Testing and Materials (ASTM) method for metalworking fluids. The ASTM method was performed on filters from "total" aerosol (open-faced, 37 mm cassettes). Thoracic aerosol was collected using personal PM10 samplers. The mean "total" aerosol exposure was 0.32 mg/m³ and the mean thoracic aerosol exposure was 0.27 mg/m³. The mean extractable mass exposure was 0.07 mg/m3 and the mean fraction of extractable mass to "total" aerosol was 0.31. Multiple linear regression models explained 0.65, 0.63 and 0.50 of the variance for the "total" aerosol, thoracic aerosol and extractable mass models respectively. The models all indicated shop height was associated with lower exposure. Operating an enclosed computer controlled (CNC) machine tool, operating a wet grinder, operating a wet saw and the presence of welding in the shop were variables that were associated with increased exposure in all three models. Other predictor variables of increased or reduced exposure were associated with the individual models. The extractable mass analysis was found to predict variables related to MWF than the aerosol models.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Determinant of exposures'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles