480 research outputs found

    Atlas of Anchorage Community Indicators

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    The Anchorage Community Indicators (ACI) project is designed to make information (extracted from data) accessible so that conversations about the health and well-being of Anchorage may become more completely informed. Policy makers, social commentators, service delivery systems, and scholars often stake out positions based on anecdotal evidence or hunches when, in many instances, solid, empirical evidence could be compiled to support or challenge these opinions.The Atlas of Anchorage Community Indicators makes empirical information about neighborhoods widely accessible to many different audiences. The initial selection of indicators for presentation in the Atlas was inspired by Peter Blau and his interest in measures of heterogeneity (diversity) and inequality and by the work of the Project on Human Development in Chicago Neighborhoods. In both cases the measures they developed were well-conceptualized and validated. The Atlas presents community indicators at the census block group level derived from data captured in the 2000 U.S. Census and the 2005 Anchorage Community Survey. All maps in the Atlas are overlaid by Community Council boundaries to facilitate comparisons across maps.Introduction / COMMUNITY COUNCIL BOUNDARY MAPS / Eagle River Community Councils / North Anchorage Community Councils / South Anchorage Community Councils / Girdwood Community Councils / CENSUS-DERIVES INDICATORS AT BLOCK GROUP LEVEL / 1. Concentrated Affluence / 2. Concentrated Disadvantage / 3. Housing Density / 4. Immigrant Concentration / 5. Index of Concentration at Extremes / 6. Industrial Heterogeneity / 7. Multiform Disadvantage / 8. Occupational Heterogeneity / 9. Population Density / 10. Racial Heterogeneity / 11. Ratio of Adults to Children / 12. Residential Stability / 13. Income Inequality // APPENDIX: ACI Technical Report: Initial Measures Derived from Censu

    Drying-mediated patterns in colloid-polymer suspensions

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    Drying-mediated patterning of colloidal particles is a physical phenomenon that must be understood in inkjet printing technology to obtain crack-free uniform colloidal films. Here we experimentally study the drying-mediated patterns of a model colloid-polymer suspension and specifically observe how the deposit pattern appears after droplet evaporation by varying particle size and polymer concentration. We find that at a high polymer concentration, the ring-like pattern appears in suspensions with large colloids, contrary to suppression of ring formation in suspensions with small colloids thanks to colloidpolymer interactions. We attribute this unexpected reversal behavior to hydrodynamics and size dependence of colloid-polymer interactions. This finding would be very useful in developing control of drying-mediated self-assembly to produce crack-free uniform patterns from colloidal fluids.ope

    Dynamically controlled deposition of colloidal nanoparticles suspension in evaporating drops using laser radiation

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    Dynamic control of the distribution of polystyrene suspended nanoparticles in evaporating droplets is investigated using a 2.9 μm high power laser. Under laser radiation a droplet is locally heated and fluid flows are induced that overcome the capillary flow, and thus a reversal of the coffee-stain effect is observed. Suspension particles are accumulated in a localised area, one order of magnitude smaller than the original droplet size. By scanning the laser beam over the droplet, particles can be deposited in an arbitrary pattern. This finding raises the possibility for direct laser writing of suspended particles through a liquid layer. Furthermore, a highly uniform coating is possible by manipulating the laser beam diameter and exposure time. The effect is expected to be universally applicable to aqueous solutions independent of solutes (either particles or molecules) and deposited substrates

    A Holocene record of climate-driven shifts in coastal carbon sequestration

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    Copyright 2009 by the American Geophysical Union.A sediment core collected in the mesohaline portion of Chesapeake Bay was found to contain periods of increased delivery of refractory black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs). The BC was most likely produced by biomass combustion during four centennial-scale dry periods as indicated by the Palmer Drought Severity Index (PDSI), beginning in the late Medieval Warm Period of 1100 CE. In contrast, wetter periods were associated with increased non-BC organic matter influx into the bay, likely due to greater runoff and associated nutrient delivery. In addition, an overall increase in both BC and non-BC organic matter deposition during the past millennium may reflect a shift in climate regime. The finding that carbon sequestration in the coastal zone responds to climate fluctuations at both centennial and millennial scales through fire occurrence and nutrient delivery has implications for past and future climate predictions. Drought-induced fires may lead, on longer timescales, to greater carbon sequestration and, therefore, represent a negative climate feedback

    Oceanic loading of wildfire-derived organic compounds from a small mountainous river

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    Copyright 2008 by the American Geophysical Union.Small mountainous rivers (SMRs) export substantial amounts of sediment into the world's oceans. The concomitant yield of organic carbon (OC) associated with this class of rivers has also been shown to be significant and compositionally unique. We report here excessively high loadings of polycyclic aromatic hydrocarbons (PAHs), lignin, and levoglucosan, discharged from the Santa Clara River into the Santa Barbara Channel. The abundance of PAHs, levoglucosan, and lignin in Santa Barbara Channel sediments ranged from 201.7 to 1232.3 ng gdw−1, 1.3 to 6.9 μg gdw−1, and 0.3 to 2.2 mg per 100 mg of the sedimentary OC, respectively. Assuming a constant rate of sediment accumulation, the annual fluxes of PAHs, levoglucosan, and lignin, to the Santa Barbara Channel were respectively, 885.5 ± 170.2 ng cm−2 a−1, 3.5 ± 1.9 μg cm−2 a−1 and 1.4 ± 0.3 mg per 100 mg OC cm−2 a−1, over ∼30 years. The close agreement between PAHs, levoglucosan, and lignin abundance suggests that the depositional flux of these compounds is largely biomass combustion-derived. To that end, use of the Santa Clara River as a model for SMRs suggests this class of rivers may be one of the largest contributors of pyrolyzed carbon to coastal systems and the open ocean. Wildfire associated carbon discharged from other high yield fluvial systems, when considered collectively, may be a significant source of lignin, pyrolytic PAHs, and other pyrogenic compounds to the ocean. Extrapolating these methods over geologic time may offer useful historical information about carbon sequestration and burial in coastal sediments and affect coastal carbon budgets

    Tracking Rotational Diffusion of Colloidal Clusters

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    We describe a novel method of tracking the rotational motion of clusters of colloidal particles. Our method utilizes rigid body transfor- mations to determine the rotations of a cluster and extends conventional proven particle tracking techniques in a simple way, thus facilitating the study of rotational dynamics in systems containing or composed of colloidal clusters. We test our method by measuring dynamical properties of simulated Brownian clusters under conditions relevant to microscopy experiments. We then use the technique to track and describe the motions of a real colloidal cluster imaged with confocal microscopy.Comment: 14 pages, 6 figures. Submitted to Optics Expres

    Macondo-1 well oil-derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico

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    Copyright 2012 by the American Geophysical UnionMesozooplankton (>200 μm) collected in August and September of 2010 from the northern Gulf of Mexico show evidence of exposure to polycyclic aromatic hydrocarbons (PAHs). Multivariate statistical analysis revealed that distributions of PAHs extracted from mesozooplankton were related to the oil released from the ruptured British Petroleum Macondo-1 (M-1) well associated with the R/VDeepwater Horizon blowout. Mesozooplankton contained 0.03–97.9 ng g−1 of total PAHs and ratios of fluoranthene to fluoranthene + pyrene less than 0.44, indicating a liquid fossil fuel source. The distribution of PAHs isolated from mesozooplankton extracted in this study shows that the 2010 Deepwater Horizon spill may have contributed to contamination in the northern Gulf of Mexico ecosystem
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