976 research outputs found
Examining the Correlation Between Coliform Bacteria and Human Wastewater in Home Well Water
Nearly 15% of the U.S. population relies on home wells for drinking water, and approximately 34% of U.S. wells test positive for coliform bacteria. However, the presence of coliform bacteria alone does not confirm the presence of fecal matter, leaving the well users uncertain of their health risk and which mitigation measures to take. Therefore, understanding the correlation between human waste and the presence of coliform bacteria is vital to public health. A significant correlation would inform well owners and public health practitioners that mitigation must include addressing home septic system(s) (the well ownerâs system as well as neighborsâ upgradient systems). The goal of this project is to analyze rural residential well water on the Crow Reservation to determine the degree of correlation between coliform presence, E coli presence and markers of human wastewater. The three primary analytes we are looking for are caffeine, cotinine and urobilin. All three chemicals are biomarkers of human waste. The methodology we are using to identify and quantify analytes within our water samples is solid phase extraction to concentrate the unknowns for further analysis using Gas Chromatography Mass Spectrometry. Subsequent analysis with colleagues will determine whether there are any significant correlations between the biomarkers of human waste and (1) the presence of coliform bacteria, (2) the presence of E. coli bacteria and/or (3) the absence of either coliform or E. coli. I will present my results to team members at a monthly meeting of the Crow Environmental Health Steering Committee, whereupon my colleagues on the Crow Reservation will use the data collected to inform and work with home well owners to properly mitigate home well contamination. After the completion of this project my colleagues and I plan on presenting this project at an additional conference and publishing in a peer review journal
Action Schools! BC: A Socioecological Approach to Modifying Chronic Disease Risk Factors in Elementary School Children
BACKGROUND: Childhood physical inactivity and obesity are serious public health threats. Socioecological approaches to addressing these threats have been proposed. The school is a critical environment for promoting children's health and provides the opportunity to explore the impact of a socioecological approach. CONTEXT: Thirty percent of children in British Columbia, Canada, are overweight or obese, and 50% of youths are not physically active enough to yield health benefits. METHODS: Action Schools! BC, a socioecological model, was developed to create 1) an elementary school environment where students are provided with more opportunities to make healthy choices and 2) a supportive community and provincial environment to facilitate change at the school and individual levels. CONSEQUENCES: The environment in British Columbia for school- and provincial-level action on health behaviors improved. Focus group and project tracking results indicated that the Action Schools! BC model enhanced the conceptual use of knowledge and was an influencing factor. Political will and public interest were also cited as influential factors. INTERPRETATION: The Action Schools! BC model required substantial and demanding changes in the approach of the researchers, policy makers, and support team toward health promotion. Despite challenges, Action Schools! BC provides a good example of how to enhance knowledge exchange and multilevel intersectoral action in chronic disease prevention
Resolvent of Large Random Graphs
We analyze the convergence of the spectrum of large random graphs to the
spectrum of a limit infinite graph. We apply these results to graphs converging
locally to trees and derive a new formula for the Stieljes transform of the
spectral measure of such graphs. We illustrate our results on the uniform
regular graphs, Erdos-Renyi graphs and preferential attachment graphs. We
sketch examples of application for weighted graphs, bipartite graphs and the
uniform spanning tree of n vertices.Comment: 21 pages, 1 figur
Spin and structural halo properties at high redshift in a LCDM Universe
In this paper, we examine in detail the key structural properties of high
redshift dark matter haloes as a function of their spin parameter. We perform
and analyze high resolution cosmological simulations of the formation of
structure in a LCDM Universe. We study the mass function, ellipticities,
shapes, density profiles, rotation curves and virialization for a large sample
of dark matter haloes from z = 15 - 6. We also present detailed convergence
tests for individual haloes. We find that high spin haloes have stronger
clustering strengths (up to 25%) at all mass and redshift ranges at these early
epochs. High redshift spherical haloes are also up to 50% more clustered than
aspherical haloes. High spin haloes at these redshifts are also preferentially
found in high density environments, and have more neighbors than their low spin
counterparts. We report a systematic offset in the peak of the circular
velocity curves for high and low spin haloes of the same mass. Therefore,
estimating halo masses without knowledge of the spin, using only the circular
velocity can yield errors of up to 40%. The strong dependence of key structural
properties on spin that we report here likely have important implications for
studies of star formation and feedback from these galaxies.Comment: 14 pages, 10 figures. Accepted to MNRAS
Sedimentology and stratigraphy of the ANDRILL McMurdo Ice Shelf (AND-1B) core
During the 2006-2007 austral summer, the ANDRILL McMurdo Ice Shelf Project recovered a core 1285 m long (AND-1B) from Windless Bight in McMurdo Sound. This core contains a range of lithologies, including both siliciclastic and volcanic diamictites, sandstones and mudstones; diatomites; and volcanic ash/tuff and one phonolitic lava flow. This sequence has been subdivided into eight lithostratigraphic units and 25 subunits, based on lithological abundances. Eleven lithofacies have been identified, ranging from open marine diatomites and mudstones to turbidites to ice-proximal massive and stratified diamictites. More than 50 glacimarine sequences have been recognized, bounded by glacial surfaces of erosion. Three distinct stacking patterns are present, showing evidence of glacial advance/retreat/advance with varying degrees of preservation. Carbonate and pyrite are the dominant secondary phases in the core. The pyrite overprint is especially notable in volcanic sediments below ~400 mbsf, where it often obscures stratification and sediment texture
Sedimentology and stratigraphy of the ANDRILL McMurdo Ice Shelf (AND-1B) core
During the 2006-2007 austral summer, the ANDRILL McMurdo Ice Shelf Project recovered a core 1285 m long (AND-1B) from Windless Bight in McMurdo Sound. This core contains a range of lithologies, including both siliciclastic and volcanic diamictites, sandstones and mudstones; diatomites; and volcanic ash/tuff and one phonolitic lava flow. This sequence has been subdivided into eight lithostratigraphic units and 25 subunits, based on lithological abundances. Eleven lithofacies have been identified, ranging from open marine diatomites and mudstones to turbidites to ice-proximal massive and stratified diamictites. More than 50 glacimarine sequences have been recognized, bounded by glacial surfaces of erosion. Three distinct stacking patterns are present, showing evidence of glacial advance/retreat/advance with varying degrees of preservation. Carbonate and pyrite are the dominant secondary phases in the core. The pyrite overprint is especially notable in volcanic sediments below ~400 mbsf, where it often obscures stratification and sediment texture
Invasion of Europe by the western corn rootworm, Diabrotica virgifera virgifera: multiple transatlantic introductions with various reductions of genetic diversity
The early stages of invasion involve demographic bottlenecks that may result in lower genetic variation in introduced populations as compared to source population/s. Low genetic variability may decrease the adaptive potential of such populations in their new environments. Previous population genetic studies of invasive species have reported varying levels of losses of genetic variability in comparisons of source and invasive populations. However, intraspecific comparisons are required to assess more thoroughly the repeatability of genetic consequences of colonization events. Descriptions of invasive species for which multiple introductions from a single source population have been demonstrated may be particularly informative. The western corn rootworm (WCR), Diabrotica virgifera virgifera, native to North America and invasive in Europe, offers us an opportunity to analyse multiple introduction events within a single species. We investigated within- and between-population variation at eight microsatellite markers in WCR in North America and Europe to investigate the routes by which WCR was introduced into Europe, and to assess the effect of introduction events on genetic variation. We detected five independent introduction events from the northern USA into Europe. The diversity loss following these introductions differed considerably between events, suggesting substantial variation in introduction, foundation and/or establishment conditions. Genetic variability at evolutionarily neutral loci does not seem to underlie the invasive success of WCR in Europe. We also showed that the introduction of WCR into Europe resulted in the redistribution of genetic variance from the intra- to the interpopulational level contrary to most examples of multiple introductions
Wind energy development can lead to guildâspecific habitat loss in boreal forest bats
Forest management rarely considers protecting bats in Fennoscandian regions although all species rely on forest habitat at some point in their annual cycle. This issue is especially evident as wind parks have increasingly been developed inside Fennoscandian forests, against the advice of international bat conservation guidelines. In this study, we aimed to describe and explain bat community dynamics at a Norwegian wind park located in a boreal forest, especially to understand potential avoidance or attraction effects. The bat community was sampled acoustically and described using foraging guilds (short, medium, and long-range echolocators; SRE, MRE, LRE) as well as behavior (commuting, feeding and social calls). Sampling was undertaken at two locations per turbine: 1) the turbine pad and 2) a paired natural habitat at ground level, as well as from a meteorological tower. We used a recently developed method for camera trapping nocturnal flying insects synchronously with bat acoustic activity. Our results reveal trends in feeding and general bat activity across foraging guilds in relation to insect availability, habitat type, wind, temperature, and seasonality. We show how seasonal patterns in behavior across guilds were affected by habitat type, temperature, and wind. We found that SRE commuting and especially feeding activity was highest in natural habitats, whereas LRE overall activity at habitats more season dependent. We found that nocturnal insect availability was positively correlated with total bat feeding activity throughout the night. Our results provide evidence for both direct and indirect risks to bat communities by wind parks: SRE bat habitat is lost to wind energy infrastructure and LRE bat may have an increased risk of fatality. Our findings provide important insights on seasonal and spatial variability in bat activity, which can inform standardizing monitoring of bats acoustically in boreal forests, at wind parks, and in combination with non-invasive insect monitoring
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