Browsing by Subject "mortality"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item Beneficial hispanic stroke mortality: An exploration of potential explanatory factors(2009-06-11) Bret Howrey; James S. Goodwin; Mukaila Raji; Ken Ottenbacher; Karl Eschbach; Jean Freeman; David Espino; Daniel FreemanStroke mortality rates are reported to be lower for Hispanics than non-Hispanic Whites. This project investigates factors that contribute to this lower rate in three ways: 1) examine the role of immigrant status in stroke incidence and mortality, 2) investigate the impact of cause of death ambiguity, and 3) examine the role of misreport of ethnicity on death certificates. \r\nIn examining the effect of immigrant status I used the Hispanic Established Populations for the Epidemiologic Study of the Elderly (EPESE) and the East Boston EPESE. This research compares baseline health characteristics of immigrants with native-born respondents. Additionally, I examine differences in stroke mortality, as well as the risk of stroke between waves. In both EPESE samples significant differences in demographics and co-morbidities existed at baseline between immigrants and the US born. However, the odds of stroke mortality or having a stroke during follow-up were not significantly different for immigrants and the US born in either the East Boston or Hispanic data. \r\n To examine the impact of cause of death coding and misreport of ethnicity on death certificates, I used national vital registration data for the years 1989-1991 and 1999-2002, including foreign and US born Hispanics and non-Hispanic Whites. Hispanic deaths were adjusted for misclassification of ethnicity on the death certificate. These data were linked to census estimates and 5% census samples for the corresponding time periods, allowing for estimates of the foreign born population. Adjustment for nativity and death certificate misclassification removed the stroke mortality advantage for US born Hispanic men, but not women. After adjustment, US born Hispanic men and women have higher rates of mortality from subarachnoid stroke than Whites (RR 1.27 and 1.27 respectively), but lower rates of mortality from Ischemic (RR 0.85 and 0.79 respectively) and chronic effects of stroke (RR 0.95 and 0.79 respectively). \r\n These results suggest that health benefits immigrants receive do not continue in older age with regards to stroke. Additionally, after adjustment for misclassification, the lower stroke mortality advantage for Hispanic men disappears, while an advantage still remains for Hispanic women. Part of the previously reported advantage is a combination of imprecise measurement and data quality.\r\nItem Early life ecology of sailfish, Istiophorus platypterus, in the northern Gulf of Mexico(2010-07-14) Simms, Jeffrey R.Sailfish, Istiophorus platypterus, are commonly taken by the recreational and commercial fisheries in the Gulf of Mexico (Gulf) and larvae are frequently reported in the region, indicating the Gulf's potential role as spawning and/or nursery ground of sailfish. Five ichthyoplankton surveys were conducted in shelf and slope waters of the northern Gulf during the summers of 2005 (May, July, September) and 2006 (June, August). Surveys were conducted off the Texas and Louisiana coasts from 27 - 28N and 88 - 94W. During the two year study, 2,426 sailfish larvae were collected, ranging in size from 2.0 - 24.3 mm standard length (SL). Sailfish larvae were collected in 45.0% of collections with a peak density ranging of 51.5 larvae per 1000 m-2 of water sampled, and the highest larval abundances were observed within frontal features of the Loop Current. Sagittal otoliths were extracted from 1,236 larvae, and otolith microstructure analysis indicated sailfish ranged in age from 5 - 25 days post-hatch. Hatch-date distributions indicated fish were from early May to mid September spawning and/or hatching events. Instantaneous growth coefficients (g) ranged from 0.113 to 0.127 with intra- and inter-annual variations in growth observed. Growth coefficients correspond to a 10.7 - 11.9% increase in length per day. Instantaneous daily mortality rates (Z) were estimated from regressions of the decline in loge-transformed abundance on age and ranged from 20.4% to 29.2% per day suggesting large losses during the early life interval. Instantaneous weight-specific growth coefficients (G) ranged from 41.5% to 45.9% per day and were indexed to daily mortality to assess intra- and inter-annual variation in recruitment potential. Recruitment indices > 1.0 were observed during all surveys, suggesting cohort biomass was increasing and that conditions were favorable for growth, survival and recruitment. The results of this study indicate that the northern Gulf represents viable spawning and nursery habitat of sailfish and the sustainability of Atlantic sailfish populations may be linked to spawning in the Gulf.Item Effect of Rate and Season of Application of Aminocyclopyrachlor on the Control of Acacia Farnesiana (L.) Willd. in South Texas(2012-07-16) McGinty, JoshuaThis study was conducted on two rangeland sites in south Texas with large populations of huisache (Acacia farnesiana (L.) Willd.); the Bush Ranch in Goliad County, and the Hitchcock Ranch in Bee County. The purpose of the study was to evaluate the effect of three herbicide treatments and three seasons of application on 1) apparent mortality of huisache, 2) huisache canopy cover, 3) huisache stem density, and 4) herbaceous ground cover. Herbicide treatments included aminocyclopyrachlor alone at a rate of 0.315 kg a.i. ha-1, aminocyclopyrachlor + triclopyr at a rate of 0.210 kg a.i. ha-1 + 0.420 kg a.e. ha-1, and triclopyr + picloram at a rate of 0.560 kg a.e. ha-1 + 0.560 kg a.e. ha-1. Herbicide treatments were applied over 3 x 30 m plots containing previously mowed huisache in May, July, and October of 2010 with ground-broadcast equipment at a rate of 140 L ha-1. Randomly selected huisache individuals and herbaceous ground cover at randomly selected points were monitored for the duration of the study. Statistical analyses of huisache mortality, canopy area, and stem densities revealed that at both sites one year after treatment, huisache mortality across the three seasons of application was consistently higher in plots treated with aminocyclopyrachlor + triclopyr (50 to 99%) versus those treated with aminocyclopyrachlor alone (16 to 78%) or triclopyr + picloram (4 to 70%). This mixture also provided the greatest reductions in huisache canopy area (60 to 99% reduction) and stem density (61 to 99% reduction). Also at both sites, spring applications consistently provided the greatest huisache control and canopy and stem reductions. Herbicide treatment and season of application had little effect on post-treatment herbaceous ground cover, likely due to extreme drought conditions in 2011. Of the possible combinations of seasons of application and herbicide treatments, the application in the spring of aminocyclopyrachlor plus triclopyr provided the most desirable results in terms of huisache mortality, canopy reduction, and stem density reduction. However, for sites invaded by huisache that are located near to potentially susceptible crops, the application of aminocyclopyrachlor plus triclopyr or aminocyclopyrachlor alone in the fall after the harvest of those crops may be more appropriate in order to avoid non-target injury while still providing acceptable huisache control.Item The incidence of death among low-risk populations: a multi-level analysis(Texas A&M University, 2007-09-17) Lewinski, Christi NicoleThis study utilized a multi-level model to examine the impact of religion as an occupation on mortality. Death certificate data were used to examine clergy mortality and compares them to census categorized professionals, counseling professionals and unmarried clergy. Individuals mortality exist in, and is influenced by the state they resided and died in. Because of this, they are not only examined on the individual level, they are also nested in their respective state of death. A series of hierarchical linear models were estimated in order to determine the effects of the different influence levels (individual and state). Findings suggest that clergy have a significant life advantage over professionals and counseling professionals. Married clergy have significant years of life disadvantage when compared to unmarried clergy. Implications of this research are discussed and considerations for future research are presented.