UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
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Item Relative impacts of determinants of childhood stunting in Malawi(2019) Kaur, Jasbir; Mehta, Mira; Desai, Sonalde B; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: High rates of stunting have persisted in Malawi for several decades. There is a need to better understand trends and determinants of childhood stunting in the population to inform effective policies and programmatic interventions. Objective: To analyze levels, trends, and distribution of stunting in a nationally-representative population of Malawian children under age five, and to analyze determinants and micronutrient levels associated with stunting in a subset of children under age two. Design: The study analyzes data from the Malawi Demographic and Health Surveys in 2000, 2004, 2010 and 2015–16 and the Malawi Micronutrient Survey in 2015–16. Stunting in children is defined as height-for-age index more than two standard deviations below the reference medium. Bivariate and multivariate analyses are used to estimate the change in stunting by socio-demographic variables, and impact of environmental enteropathy, water sanitation and hygiene, access to food, infant and young child feeding practices, women’s empowerment, domestic violence, and biomarkers of nutrition, specifically iron- deficiency anemia and vitamin A deficiency controlled for inflammation in children ages 0–59 months, adjusted for sampling design effects. Setting: Malawi is a landlocked country, divided into three regions: the northern, central, and southern regions. Subjects: Children ages 0–59 months with data on anthropometric measurements from the MDHS survey in 2000 (n=9,188), 2004 (n=8,090), 2010 (n=4,586), and 2016 (n=5,149), and from the MNS survey in 2015¬–16 (n=2,018). Results: The prevalence of stunting decreased in children from 54.3 percent in 2000 to 36.6 percent in 2016. Child’s household structure (a finished roof), child’s age, gender, birth order and birth interval, household wealth, land ownership, mother’s education, mother’s stature and BMI, and mother’s age appear to be the strongest determinants of childhood stunting. With addition of biomarkers of nutrition, inflammation, and inherited disorders, age of the child, birth order, and mother’s report of child’s size at birth and household hunger are major determinants of childhood stunting. At the cellular level, serum ferritin, retinol binding protein, and sickle cell disease and alpha-thalassemia are strongly associated with stunting in children.Item Classification of Northern Hemisphere Stratospheric Ozone and Water Vapor Profiles by Meteorological Regime: Validation, Climatology, and Trends(2007-01-19) Follette, Melanie Beth; Hudson, Robert D.; Atmospheric and Oceanic Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The presence of stratospheric ozone is essential for the survival of life on the Earth's surface. The decrease in the column content of ozone over mid-latitudes from 1979-1991 has previously been attributed to destruction by anthropogenic halogens, and changes in the general circulation. The research presented here shows that a poleward movement of the subtropical and polar upper troposphere fronts is responsible for 35% of this observed decrease. In Hudson et al. (2003) we showed that the Northern Hemisphere total ozone field could be separated into meteorological regimes, bounded by the subtropical and polar upper troposphere fronts. These regimes were characterized by relatively constant total ozone, tropopause height, and ozonepause height. Negative trends in total ozone within each regime were found for the time period January 1979-May 1991. These trends corresponded to a statistically significant increase in the relative area of the tropical regime, and decrease in the relative area of the polar regime, indicating a net poleward movement of the subtropical and polar fronts over this time period. This poleward frontal movement was responsible for ~35% of the negative zonal trend in total ozone over this time period and latitude range, the remaining 65% being the result of total ozone changes within the meteorological regimes. Ozone and water vapor profiles from 1997-2004, from the HALOE and SAGE II satellite-based instruments, were classified by regime. Each regime was characterized by a distinct ozonepause and hygropause height, and profile shape below ~25km, over a wide latitude range (25°-60°N). Therefore, previously reported zonal trends in the lower stratosphere and upper troposphere are a combination of both tropospheric and stratospheric air. Trends within each regime were calculated for both ozone and water vapor from 1997-2004 and from October 1984-May 1991. The relationship between the observed zonal vertical trends and the trends within each regime were consistent with the idea of meteorological regimes and reinforce the major conclusion of this work. A true understanding of zonal trends in either the column or in the lower stratosphere involves understanding both changes within each regime and changes in the relative weighting of each regime over time.