25 research outputs found

    Cardiometabolic Risk Assessments by Body Mass Index z -Score or Waist-to-Height Ratio in a Multiethnic Sample of Sixth-Graders

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    Convention defines pediatric adiposity by the body mass index z-score (BMIz) referenced to normative growth charts. Waist-to-height ratio (WHtR) does not depend on sex-and-age references. In the HEALTHY Study enrollment sample, we compared BMIz with WHtR for ability to identify adverse cardiometabolic risk. Among 5,482 sixth-grade students from 42 middle schools, we estimated explanatory variations (R2) and standardized beta coefficients of BMIz or WHtR for cardiometabolic risk factors: insulin resistance (HOMA-IR), lipids, blood pressures, and glucose. For each risk outcome variable, we prepared adjusted regression models for four subpopulations stratified by sex and high versus lower fatness. For HOMA-IR, R2 attributed to BMIz or WHtR was 19%-28% among high-fatness and 8%-13% among lower-fatness students. R2 for lipid variables was 4%-9% among high-fatness and 2%-7% among lower-fatness students. In the lower-fatness subpopulations, the standardized coefficients for total cholesterol/HDL cholesterol and triglycerides tended to be weaker for BMIz (0.13-0.20) than for WHtR (0.17-0.28). Among high-fatness students, BMIz and WHtR correlated with blood pressures for Hispanics and whites, but not black boys (systolic) or girls (systolic and diastolic). In 11-12 year olds, assessments by WHtR can provide cardiometabolic risk estimates similar to conventional BMIz without requiring reference to a normative growth chart

    Modeling of PV Penetration in Residential Neighborhoods on Aruba

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    Aruba is a small island in the Caribbean. It has 101,484 inhabitants and its main income is tourism. As an island it is dependent on fossil fuel to generate its electric energy. As a result of the increasing oil price, it is attractive to be an island that generates its own electric energy through sustainable generators. This is the reason that the Aruban government made an ambitious plan to make the Aruba a self-sustainable island by 2020. To accomplish this plan, one of the goals that need to be accomplished is, to know what the current status is on integration of Photovoltaic (PV) systems is, and what is needed for in the future for integration more PV systems. To summarized; the main goal of this thesis is to know how many PV systems can be integrated in the current grid without modification and what modification is needed to integrate more PV systems into the grid.Electrical Power EngineeringElectrical Engineering, Mathematics and Computer Scienc

    Biogeochemical status of the Paleo-Pacific Ocean: clues from the early Cambrian of South Australia

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    Published online: 28 Mar 2021The Ediacaran–Cambrian transition was a time of profound reorganisation of the biosphere, coinciding with the assembly of Gondwana and increasing atmospheric and oceanic oxygenation. The lower Cambrian marine sediments of the Stansbury Basin, South Australia, were deposited at low northern paleolatitudes on the western margin of the emerging Pacific Ocean. Here we report results of a multi-pronged investigation employing trace and rare earth element (REE) abundances, total organic carbon (TOC) contents and pyritic sulfur isotopic compositions (δ34Spy) in carbonaceous shales from three formations within the Normanville and Kanmantoo groups (sequences Є1.2 to Є2.2). TOC ranges from ≤0.5 wt% in the Emu Bay Shale, through 0.4–1.9 wt% in the Talisker Formation, to 0.2–2.6 wt% in the Heatherdale Shale. Covariance is demonstrated between trace elements and organic matter, with comparative uranium enrichment in the Heatherdale Shale likely linked to increased primary productivity. Heavy REEs and yttrium are typically more depleted than light REEs. Provenance appears to evolve through the upper Normanville sediments into the Kanmantoo Group, corroborating published detrital zircon interpretations that suggest an increasing dominance of southerly derived sources. The prevailing paleoredox regime for the Heatherdale Shale and the Talisker Formation was dysoxic, evolving into progressively more reducing conditions up section, the latter exhibiting a secular decline in δ34Spy (from +10 to −11‰ VCDT). Conversely, redox proxies concur in demonstrating that the basal fossiliferous Emu Bay Shale accumulated beneath an oxic water column. Comparison of trace element and REE distributions with those of slightly older sequences on the Yangtze Platform, South China, reveals striking similarities, implying that the trace element chemistry of the Paleo-Pacific and Asian oceans was homogeneous.P. A. Hall, D. M. McKirdy, G. P. Halverson, J. B. Jago and A. S. Collin

    The Cambrian System in the Arrowie Basin, Flinders Ranges, South Australia

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    The lower to ?middle Cambrian rocks (Terreneuvian, Series 2 and possibly Miaolingian) of the Arrowie Basin are exposed superbly in the Flinders Ranges of South Australia. They comprise two major sedimentary packages: a lower carbonate-rich succession (Hawker Group and correlates) and an upper siliciclastic-dominated succession (Billy Creek Formation, Wirrealpa Limestone and Lake Frome Group). These rocks form one of the most complete lower Cambrian (Terreneuvian and Series 2) successions globally. They contain one of the most diverse known early Cambrian biotas in the world, with trilobites, archaeocyaths, bradoriides, brachiopods, some of the earliest known coralomorphs, small shelly fossils, molluscs, hyoliths, acritarchs and trace fossils. Series divisions, based on ranges of shelly fossils and archaeocyath biostratigraphy are currently being established. Ancient reef structures are prominent in several areas. Syndepositional faulting and diapiric activity affected sedimentation in places. The global significance of the region is enhanced by the presence of tuff horizons at some levels, which provide the opportunity to link the biostratigraphic zones with radiometric dates and carbon isotope curves.J. B. Jago, J. G. Gehling, M. J. Betts, G. A. Brock, C. R. Dalgarno, D. C. García-Bellido, P. G. Haslett, S. M. Jacquet, P. D. Kruse, N. R. Langsford, T. J. Mount, J. R. Paterso
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