29,362 research outputs found
An investigation of fall protection systems in the roofing industry
No full textThesis Chair, Dr. Sang D. Choi.
This file was last viewed in Adobe Reader 7.0Construction is one of most dangerous industries in the United States. One of the most hazardous areas within the construction industry is roofing. Concern for safety in roofing construction has continued to spread, as a result of falls that make up the greatest rate of fatalities in the construction industry. Previous research has found that falls have been one of the leading categories under type of occupational death and that fall protection systems are not consistently used to prevent fall accidents in the roofing industry. Research is needed in order to analyze falls and other potential hazards in roofing. The main goal for this study is to analyze commercial and residential roofers’ behaviors, attitudes, and beliefs on the fall protection systems. A survey was distributed to commercial and residential roofers in the Midwest. Information collected from roofers was compared and analyzed to find differences between residential and commercial roofers. A total of 129 roofing contractors participated in this study. The results of the survey showed that while most of commercial roofers did use fall protection devices, a significant number of residential roofers did not comply with fall protection regulations and guidelines. Two main reasons of noncompliance with fall protection regulations and guidelines in roofing construction were found: (1) fall protection devices decrease productivity; (2) fall protection equipment makes roofers uncomfortable. Results from this study revealed that personal fall arrest system (PFAS) was the most prevalent fall protection device used among residential and commercial roofers. PFAS was also the most preferred fall protection equipment among the two groups of roofers. For both residential and commercial roofing, there is a significant (p = 0.05 and p = 0.01) negative relationship between enforcing roofers to wear or install fall protection devices and having falls from roofs. In both residential and commercial roofing, there is a very significant (p= 0.001 and p = 0.001) positive relationship between the enforcement and the actual usage of fall protection equipment. This thesis presents the results of the investigation of fall protection systems in roofing construction and recommendations that ultimately would reduce fall accidents
Size at birth and plasma leptin concentrations in adult life
No full textObjectiveTo determine whether low birthweight is associated with higher plasma leptin concentrations in adult life and whether leptin contributes to the metabolic alterations in adults that are associated with reduced foetal growth.DesignMeasurement of plasma leptin concentrations in a group of 502 men and women, aged 61-73, who were born in Hertfordshire and for whom records of birth and infant weight are available. Glucose tolerance was measured with a standard 75 g oral glucose tolerance test.MeasurementsLeptin concentrations were assayed in fasting plasma samples using a radioimmunoassay.ResultsLeptin concentrations ranged from 1.4 to 128.9 (mean 13.4) ng/ml and were higher in the 193 women than the 309 men (23.4 vs. 7.1 ng/ml). In both sexes leptin concentrations correlated positively with body mass index (r=0.65 in both men and women). Leptin concentration also correlated with fasting insulin (r=0.41) and with glucose and insulin concentrations 2 h after a glucose load (r=0.19 and 0.49). Adults with lower birth or infant weight had higher leptin concentrations than those of higher birthweight with similar degrees of obesity (P=0.02 and 0.06, respectively). Although both 2 h glucose and insulin concentrations negatively correlated with birthweight (r=-0.17, PConclusionThese results suggest that adults who had had low birthweight had higher plasma concentrations of leptin than would be expected from their degree of obesity. The higher leptin concentrations, however, do not account for the association between birthsize and glucose tolerance. They may be a consequence of the altered body composition, hyperinsulinaemia, and other long-term endocrine changes associated with reduced foetal growth
Birth size and physical activity in a cohort of Indian children aged 6-10 years
No full textThere is evidence of a reduction in children’s physical activity in India in the last decade. Our objective was to assess whether size and body composition at birth are associated with physical activity in school-aged children. Children from a prospective observational cohort study born in Mysore, South India between 1997 and 1998 (n5663) had neonatal anthropometric measurements made within 72 h of delivery [weight, mid-upper arm circumference (MUAC), chest, abdomen and head circumference, crown–heel, crown–buttock and leg length, triceps and subscapular skinfolds]. At 6–10 years, children (n5449) were asked to wear AM7164 or GT1M Actigraph accelerometers for 7 days. Body composition was measured within 6 months of activity monitoring. Arm muscle area at birth and time of activity monitoring was calculated from MUAC and skinfold measurements. Activity outcome measures were: mean accelerometer counts per minute (cpm); counts per day and proportion of time spent in moderate and vigorous activity. The mean (S.D.) number of days with >500 min of recorded accelerometer data was 7.0 (1.1). Linear regression models showed no significant associations between any of the neonatal anthropometric measures and the activity variables. Body fat percentage at 7.5 years was negatively associated with all activity variables (B524.69, CI: 27.31, 22.07 for mean cpm). In conclusion, this study showed no associations between body size and skinfold thickness at birth and objectively measured physical activityin childhood
A principal components approach to parent-to-newborn body composition associations in South India
No full textBackground: size at birth is influenced by environmental factors, like maternal nutrition and parity, and by genes. Birth weight is a composite measure, encompassing bone, fat and lean mass. These may have different determinants. The main purpose of this paper was to use anthropometry and principal components analysis (PCA) to describe maternal and newborn body composition, and associations between them, in an Indian population. We also compared maternal and paternal measurements (body mass index (BMI) and height) as predictors of newborn body composition.Methods: weight, height, head and mid-arm circumferences, skinfold thicknesses and external pelvic diameters were measured at 30 ± 2 weeks gestation in 571 pregnant women attending the antenatal clinic of the Holdsworth Memorial Hospital, Mysore, India. Paternal height and weight were also measured. At birth, detailed neonatal anthropometry was performed. Unrotated and varimax rotated PCA was applied to the maternal and neonatal measurements.Results: rotated PCA reduced maternal measurements to 4 independent components (fat, pelvis, height and muscle) and neonatal measurements to 3 components (trunk+head, fat, and leg length). An SD increase in maternal fat was associated with a 0.16 SD increase (?) in neonatal fat (p < 0.001, adjusted for gestation, maternal parity, newborn sex and socio-economic status). Maternal pelvis, height and (for male babies) muscle predicted neonatal trunk+head (? = 0. 09 SD; p = 0.017, ? = 0.12 SD; p = 0.006 and ? = 0.27 SD; p < 0.001). In the mother-baby and father-baby comparison, maternal BMI predicted neonatal fat (? = 0.20 SD; p < 0.001) and neonatal trunk+head (? = 0.15 SD; p = 0.001). Both maternal (? = 0.12 SD; p = 0.002) and paternal height (? = 0.09 SD; p = 0.030) predicted neonatal trunk+head but the associations became weak and statistically non-significant in multivariate analysis. Only paternal height predicted neonatal leg length (? = 0.15 SD; p = 0.003).Conclusion: principal components analysis is a useful method to describe neonatal body composition and its determinants. Newborn adiposity is related to maternal nutritional status and parity, while newborn length is genetically determined. Further research is needed to understand mechanisms linking maternal pelvic size to fetal growth and the determinants and implications of the components (trunk v leg length) of fetal skeletal growt
Size at birth, morning cortisol and cardiometabolic risk markers in healthy Indian children
No full textObjective: Prenatal programming of the hypothalamic-pituitary-adrenal (HPA) axis may link reduced fetal growth with higher adult chronic disease risk. South Asians have a high prevalence of low birth weight and a thin-fat phenotype which is associated with subsequent type 2 diabetes and the metabolic syndrome. Altered HPA activity could be one of the pathological processes underlying this link. Methods: Plasma morning cortisol and corticosteroid binding globulin (CBG) concentrations were determined in 528 children aged 9.5 years from a prospective birth cohort in India. They had detailed anthropometry at birth, and current measurements of anthropometry, plasma glucose, insulin and lipid concentrations and blood pressure. Insulin resistance (Homeostasis Model Assessment) and insulin secretion (the 30-minute insulin increment) were also assessed. Results: None of the birth measurements were associated with cortisol concentrations, but both birth weight (P=0.03) and length (P=0.004) were inversely associated with CBG concentrations. Cortisol concentrations were inversely associated with current body mass index (P=0.02), and positively associated with glucose (fasting: P<0.001; 30-minute: P=0.002) concentrations, and systolic blood pressure (P=0.005) but not insulin resistance or the insulin increment. Conclusion: Higher morning cortisol is associated with higher cardiometabolic risk markers in Indian children. Although cortisol concentrations did not appear to be related to birth size, small size at birth was associated with higher CBG levels, and may be one of the processes by which fetal undernutrition affects adult health. The findings suggest a need for dynamic testing of HPA axis activity (such as measuring stress responses). © 2013 Blackwell Publishing Ltd
Elevated plasma cortisol concentrations: a link between low birth weight and the insulin resistance syndrome?
No full textRecent studies have shown that reduced fetal growth is associated with the development of the insulin resistance syndrome in adult life. The mechanisms are not known. However increased activity of the hypothalamic-pituitary-adrenal axis (HPAA) may underlie this association; the axis is known to be reset by fetal growth retardation in animals, and there is evidence in humans of an association between raised HPAA activity and the insulin resistance syndrome. We have, therefore, examined the relations among size at birth, plasma cortisol concentrations, and components of the insulin resistance syndrome in a sample of healthy men. We measured 0900 h fasting plasma cortisol and corticosteroid-binding globulin levels in 370 men who were born in Hertfordshire, UK, between 1920-1930 and whose birth weights were recorded. Fasting plasma cortisol concentrations varied from 112-702 nmol/L and were related to systolic blood pressure (P = 0.02), fasting and 2-h plasma glucose concentrations after an oral glucose tolerance test (P = 0.0002 and P = 0.04), plasma triglyceride levels (P = 0.009), and insulin resistance (P = 0.006). Plasma cortisol concentrations fell progressively (P = 0.007) from 408 nmol/L in men whose birth weights were 5.5 lb (2.50 kg) or less to 309 nmol/L among those who weighed 9.5 lb (4.31 kg) or more at birth, a trend independent of age and body mass index. These findings suggest that plasma concentrations of cortisol within the normal range could have an important effect on blood pressure and glucose tolerance. Moreover, this study provides the first evidence that intrauterine programming of the HPAA may be a mechanism underlying the association between low birth weight and the insulin resistance syndrome in adult life.</p
Vitamin D Supplementation Is Associated with a Reduction in Self-Reported Falls among Older Adults with Previous Fall History — Feasibility Study
No full textBackground: Vitamin D insufficiency contributes to muscle weakness and a higher risk of falls in older adults. Objectives: This study explored the impact of vitamin D supplementation on self-reported falls and physical function in older adults with low vitamin D levels and a recent fall history. Materials and Methods: Twenty-five older adults ≥ 70 years with two or more falls during the past year, low vitamin D blood levels (≥10 ng/ml and < 30 ng/mL), and slow gait speed (1.2 m/s) participated in a 6-month vitamin D supplementation (800 IU/day) study. A modified version of the Morse Fall Scale questionnaire was used to assess frequency of falls over one-year prior to study enrollment. Functional outcomes (short physical performance battery, handgrip strength, gait Timed Up and Go, and six-minute walk), and vitamin D levels were assessed at baseline and 6-month follow-up. Results: Based on diaries and pill counts, participants were generally adherent to the intervention (6 of 7 days per week). Supplementation with 800 IU/day of vitamin D for 6 months increased blood vitamin D levels from 23.25±4.8 ng/ml to 29.13±6.9 ng/ml (p<0.001). Self-reported number of falls decreased from an average of 3.76 ± 2.2 falls in one-year to 0.76 ± 1.4 falls (p <0.0001) over the 6-month intervention. No changes in functional outcome measures were observed. Conclusions: Vitamin D supplementation at the currently recommended dose of 800 IU/day increased blood vitamin D levels and reduced frequency of falls in older adults with low vitamin D levels and a recent fall history
A comparative field study of free-fall cone and sphere penetrometers in soft sediment
No full textThis paper describes the field performance of two instrumented free-fall penetrometers (FFPs), which offer the possibility of low cost rapid strength profiling without requiring the equipment associated with conventional CPTs or drilling and sampling. The devices considered are a free-fall cone penetrometer (FFcP) and an instrumented free-fall sphere (IFFS). The performance of the FFPs in assessing soil undrained shear strength was investigated and compared through field trials in the soft sediments of the Swan River, Perth, Western Australia. The penetrometers achieved impact velocities of 1.4–5.8 m/s from drop heights of 0.7–3.0 m above the riverbed, and embedded to depths of up to 1.6 times the FFP length (1.45 m) and 4.5 times the IFFS diameter (0.89 m). The FFP data provided the shear strength indirectly using the acceleration measured from an onboard inertial measurement unit. The accuracy depends on the assumptions made regarding the magnitude of dynamic bearing and shaft frictional resistance. Uncertainty associated with dynamic bearing resistance causes a ±10% and ±13% variation in the calculated strength for the IFFS and the FFcP, respectively. However, the equivalent uncertainty in dynamic shaft resistance can cause a variation in the calculated strength of up to ±76% for the FFcP. The FFcP has higher embedment potential than the IFFS, but the IFFS has the advantage of a simpler interpretation without needing to account for dynamic shaft resistance
Understanding hydrological processes in small Alpine and pre-Alpine catchments: the case of Rio Vauz and Ressi, Northern Italy
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