228 research outputs found

    Bedrock Geology of the Shin Pond-Traveler Mountain Region

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    Early Ascents and Geologic Exploration of Katahdin in the Nineteenth Century; Bedrock Geology of the Shin Pond Region

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    Guidebook for field trips in the Mount Katahdin Region, Maine: 58th annual meeting September 29, 30, October 1, 1966: title page, table of contents, introduction, essay

    Decadal changes in summertime reactive oxidized nitrogen and surface ozone over the Southeast United States

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    Widespread efforts to abate ozone (O3) smog have significantly reduced emissions of nitrogen oxides (NOx) over the past 2 decades in the Southeast US, a place heavily influenced by both anthropogenic and biogenic emissions. How reactive nitrogen speciation responds to the reduction in NOx emissions in this region remains to be elucidated. Here we exploit aircraft measurements from ICARTT (July–August 2004), SENEX (June–July 2013), and SEAC4RS (August–September 2013) and long-term ground measurement networks alongside a global chemistry–climate model to examine decadal changes in summertime reactive oxidized nitrogen (RON) and ozone over the Southeast US. We show that our model can reproduce the mean vertical profiles of major RON species and the total (NOy) in both 2004 and 2013. Among the major RON species, nitric acid (HNO3) is dominant (∼ 42–45%), followed by NOx (31%), total peroxy nitrates (ΣPNs; 14%), and total alkyl nitrates (ΣANs; 9–12%) on a regional scale. We find that most RON species, including NOx, ΣPNs, and HNO3, decline proportionally with decreasing NOx emissions in this region, leading to a similar decline in NOy. This linear response might be in part due to the nearly constant summertime supply of biogenic VOC emissions in this region. Our model captures the observed relative change in RON and surface ozone from 2004 to 2013. Model sensitivity tests indicate that further reductions of NOxemissions will lead to a continued decline in surface ozone and less frequent high-ozone events

    Evaluation of Autogenous Engineered Septal Cartilage Grafts in Rabbits: A Minimally Invasive Preclinical Model

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    Objectives. (1) Evaluate safety of autogenous engineered septal neocartilage grafts and (2) compare properties of implanted grafts versus controls. Study Design. Prospective, basic science. Setting. Research laboratory. Methods. Constructs were fabricated from septal cartilage and then cultured in vitro or implanted on the nasal dorsum as autogenous grafts for 30 or 60 days. Rabbits were monitored for local and systemic complications. Histological, biochemical, and biomechanical properties of constructs were evaluated. Results. No serious complications were observed. Implanted constructs contained more DNA (P<0.01) and less sGAG perDNA (P<0.05) when compared with in vitro controls. Confined compressive aggregate moduli were also higher in implanted constructs (P<0.05) and increased with longer in vivo incubation time (P<0.01). Implanted constructs displayed resorption rates of 20–45 percent. Calcium deposition in implanted constructs was observe. Conclusion. Autogenous engineered septal cartilage grafts were well tolerated. As seen in experiments with athymic mice, implanted constructs accumulated more DNA and less sGAG when compared with in vitro controls. Confined compressive aggregate moduli were higher in implanted constructs. Implanted constructs displayed resorption rates similar to previously published studies using autogenous implants of native cartilage

    Crafting organization

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    The recent shift in attention away from organization studies as science has allowed for consideration of new ways of thinking about both organization and organizing and has led to several recent attempts to \u27bring down\u27 organizational theorizing. In this paper, we extend calls for organization to be represented as a creative process by considering organization as craft. Organizational craft, we argue, is attractive, accessible, malleable, reproducible, and marketable. It is also a tangible way of considering organization studies with irreverence. We draw on the hierarchy of distinctions among fine art, decorative art, and craft to suggest that understanding the organization of craft assists in complicating our understanding of marginality. We illustrate our argument by drawing on the case of a contemporary Australian craftworks and marketplace known initially as the Meat Market Craft Centre (\u27MMCC\u27) and then, until its recent closure, as Metro! &Dagger; Stella Minahan was a board member and then the Chief Executive Officer of the Metro! Craft Centre.<br /

    Sustainable Urban Systems: Co-design and Framing for Transformation

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    Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social–ecological–technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at multiple scales. Such holistic urban approaches are rare in practice. A co-design process involving researchers, practitioners and other stakeholders, has progressed such an approach in the Australian context, aiming to also contribute to international knowledge development and sharing. This process has generated three outputs: (1) a shared framework to support more systematic knowledge development and use, (2) identification of barriers that create a gap between stated urban goals and actual practice, and (3) identification of strategic focal areas to address this gap. Developing integrated strategies at broader urban scales is seen as the most pressing need. The knowledge framework adopts a systems perspective that incorporates the many urban trade-offs and synergies revealed by a systems view. Broader implications are drawn for policy and decision makers, for researchers and for a shared forward agenda

    High-latitude dust in the Earth system

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    Natural dust is often associated with hot, subtropical deserts, but significant dust events have been reported from cold, high latitudes. This review synthesizes current understanding of high-latitude (&ge;50&deg;N and &ge;40&deg;S) dust source geography and dynamics and provides a prospectus for future research on the topic. Although the fundamental processes controlling aeolian dust emissions in high latitudes are essentially the same as in temperate regions, there are additional processes specific to or enhanced in cold regions. These include low temperatures, humidity, strong winds, permafrost and niveo-aeolian processes all of which can affect the efficiency of dust emission and distribution of sediments. Dust deposition at high latitudes can provide nutrients to the marine system, specifically by contributing iron to high-nutrient, low-chlorophyll oceans; it also affects ice albedo and melt rates. There have been no attempts to quantify systematically the expanse, characteristics, or dynamics of high-latitude dust sources. To address this, we identify and compare the main sources and drivers of dust emissions in the Northern (Alaska, Canada, Greenland, and Iceland) and Southern (Antarctica, New Zealand, and Patagonia) Hemispheres. The scarcity of year-round observations and limitations of satellite remote sensing data at high latitudes are discussed. It is estimated that under contemporary conditions high-latitude sources cover &gt;500,000 km2&nbsp;and contribute at least 80&ndash;100 Tg yr&minus;1&nbsp;of dust to the Earth system (~5% of the global dust budget); both are projected to increase under future climate change scenarios
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