2,481 research outputs found

    Geotechnical assessment strategy for bridge maintenance – case study.

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    This paper presents a practical strategy used to conduct a geotechnical assessment, drawing principally on a maintenance work carried out recently for Rashwood Interchange which carries the M5 Motorway over the A38. The bridge, which was constructed in the early 1960s, had experienced long-term settlement attributed to historical brine pumping activities in the proximity of the bridge area. In planning for its maintenance work several issues challenged the geotechnical assessment, including the review of settlement history and mining instability in the area, the exploitation of as-built data records and the determination of foundation response to additional loading during the bridge repair. The paper presents how these complex challenges were approached, yet using simple procedures and common design tools. The procedures are also applicable to other infrastructure maintenance projects, particularly in transportation geotechnics.N/

    Microfluidic SAXS study of lamellar and multilamellar vesicle phases of linear sodium alkylbenzenesulfonate surfactant with intrinsic isomeric distribution

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    The structure and flow behaviour of a concentrated aqueous solution (45 w.t. %) of the ubiquitous linear sodium alkylbenzene sulfonate (NaLAS) surfactant is investigated by microfluidic small-angle X-ray scatterong (SAXS) at 70 ⁰C. NaLAS is an intrinsically complex mixture of over 20 surfactant molecules, presenting coexisting micellar (L1) and lamellar (Lα) phases. Novel microfluidic devices were fabricated to ensure pressure and thermal resistance, ability to handle viscous fluids, and low SAXS background. Polarized light optical microscopy showed that the NaLAS solution exhibits wall slip in microchannels, with velocity profiles approaching plug flow. Microfluidic SAXS demonstrated the structural spatial heterogeneity of the system with a characteristic lengthscale of 50 nL. Using a statistical flow-SAXS analysis we identified the micellar phase and multiple coexisting lamellar phases with a continuous distribution of d spacings between 37.5 Å - 39.5 Å. Additionally, we showed that the orientation of NaLAS lamellar phases is strongly affected by a single microfluidic constriction. The bilayers align parallel to the velocity field upon entering a constriction and perpendicular to it upon exiting. On the other hand, multi-lamellar vesicle phases are not affected under the same flow conditions. Our results demonstrate that, despite the compositional complexity inherent to NaLAS, microfluidic SAXS can rigorously elucidate its structure and flow response

    The effects of nitroxyl (HNO) on soluble guanylate cyclase activity: interactions at ferrous heme and cysteine thiols

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    It has been previously proposed that nitric oxide (NO) is the only biologically relevant nitrogen oxide capable of activating the enzyme soluble guanylate cyclase (sGC). However, recent reports implicate HNO as another possible activator of sGC. Herein, we examine the affect of HNO donors on the activity of purified bovine lung sGC and find that, indeed, HNO is capable of activating this enzyme. Like NO, HNO activation appears to occur via interaction with the regulatory ferrous heme on sGC. Somewhat unexpectedly, HNO does not activate the ferric form of the enzyme. Finally, HNO-mediated cysteine thiol modification appears to also affect enzyme activity leading to inhibition. Thus, sGC activity can be regulated by HNO via interactions at both the regulatory heme and cysteine thiols

    Interspecific interactions between Penstemon palmeri and shrubs in the arid shrublands of the Spring Mountains, Nevada

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    A project involving shrub removal was undertaken by the United States Forest Service in the Spring Mountains National Recreation Area (SMNRA) to reduce accumulated woody fuels, which can pose risks to human communities. This research focuses on the interactions between shrubs and the perennial forb Palmer\u27s penstemon (Penstemon palmeri), one of many nectar sources for the endemic Spring Mountains Acastus Checkerspot Butterfly (Chlosyne acastus ssp robusta). Initial observations revealed that P. palmeri (`penstemon\u27) seemed to grow almost exclusively under shrubs. Such spatial associations are often indicative of a history of positive interactions between plants, and led to the research presented here. These studies investigate and discuss the interactions between this penstemon and shrubs in the arid shrublands of the SMNRA. Spatial patterns between populations of penstemon and shrubs were measured during November 2008-May 2011, and the consequences of shrub-association for individual penstemon emergence, survival, growth, and reproduction were documented (Chapter 2). The results suggest that although shrubs reduced penstemon emergence, they increased seedling survival (a seed-seedling conflict) resulting in a strong shift toward association between shrubs and penstemon over time. Further, while no differences in growth were detected between microhabitats, the results suggest that shrubs inhibited P. palmeri flowering but improved the successful maturation of fruits when flowering occurred. The mechanisms driving these patterns were elusive, but seed-sowing and seedling transplant experiments suggested that shrub soils, rather than their canopies, alter the nature of seed-seedling conflicts in a way that may promote seed-bank persistence in penstemon populations (Chapter 3). To provide a detailed description of the reproductive response of penstemon to shrubs, structural equation modeling was used to describe the importance of shrubs for penstemon seed production (Chapter 4). The results suggest that competition with shrubs reduced penstemon seed production, but that shrubs simultaneously facilitated penstemon water balance and altered the foraging behavior of its pollinators, indirectly increasing seed production. I conclude by discussing the importance of these studies, and studies of plant interactions in general, for helping land managers balance the objectives of fuel load reduction with protecting desirable species (Chapter 5)

    Revisiting the Local Scaling Hypothesis in Stably Stratified Atmospheric Boundary Layer Turbulence: an Integration of Field and Laboratory Measurements with Large-eddy Simulations

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    The `local scaling' hypothesis, first introduced by Nieuwstadt two decades ago, describes the turbulence structure of stable boundary layers in a very succinct way and is an integral part of numerous local closure-based numerical weather prediction models. However, the validity of this hypothesis under very stable conditions is a subject of on-going debate. In this work, we attempt to address this controversial issue by performing extensive analyses of turbulence data from several field campaigns, wind-tunnel experiments and large-eddy simulations. Wide range of stabilities, diverse field conditions and a comprehensive set of turbulence statistics make this study distinct

    Practical mammography

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    ‘Digital health’ is an overarching concept that currently lacks theoretical definition and common terminology. For instance, this broad and emerging field includes all of the following terms within its lexicon: mHealth, Wireless Health, Health 2.0, eHealth, e-Patient(s), Healthcare IT/Health IT, Big Data, Health Data, Cloud Computing, Quantified Self, Wearable Computing, Gamification, and Telehealth/Telemedicine [1]. However, whilst a definition is difficult to provide, in this overview it is considered that digital health is the use of digital media to transform the way healthcare provision is conceived and delivered. We consider it does this through three basic features

    A Sky Island Fire Ecology Primer, with a Focus on Chiricahua National Monument: A Reference Document for the National Park Service

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    Fire is a keystone ecological process in the vegetation of the Sky Islands of Arizona and beyond, affecting every aspect of these ecosystems, including soils, forest structure, species composition, carbon storage, wildlife populations, and much more. For thousands of years, wildfires have been, not a disruptive external force, but an intrinsic part of these natural communities, as integral as water, sunlight, soil, and air. Times have changed. Human-induced fire suppression and climate change have dramatically altered fire regimes across the region, and the fires of the 21st century are a serious problem. Not only are uncharacteristically large and intense fires disrupting ecosystems that historically experienced more frequent, low-intensity wildfire, they are also threatening human communities in the rapidly-growing wildland-urban interface. A key recommendation of the 2007 Statewide Strategy for Restoring Arizona’s Forests was that “The Arizona State Legislature, county and local governments, tribal governments, and state agencies should develop land use policies and practices that support forest restoration, community protection, and fire management efforts.” (Recommendation 2.2, p.9). The goal of this essay is to discuss the landscape role of fire in the Sky Islands of southern Arizona, and in particular Chiricahua National Monument. We will describe fire and vegetation conditions before Euro-American settlement, changes in fire regime and ecosystems wrought over the past 150 years, the accompanying shifts in plant communities, and projections for the future. We will marshal our recent field research, tying our results to specific places in the park, but we will also summarize general principles developed from many decades of ecological research across the Southwest. Our mission is to provide essential fire ecology background for park staff, who enlighten park visitors about the ecologically-rich and regionally-important environments of Chiricahua National Monument (CHIR)

    Implementing Arts on Prescription at Home for People Living With Dementia: A Hybrid-Effectiveness Feasibility Study

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    Arts on prescription at home (AoP@Home) is a participatory art-based approach involving a professional artist engaging a person with dementia (and their family carer) in art-making in their own home. This study evaluated the implementation of AoP@Home within a real-world community aged care context. A hybrid effectiveness-implementation design was used to simultaneously test both the AoP@Home intervention and the implementation process. AoP@Home program outcomes included person with dementia and family carer (dyad) health and wellbeing, and personal goal attainment. Implementation outcomes were evaluated according to feasibility, fidelity, acceptability, uptake, and costs via routinely collected data, artist notes, and interviews with program managers, artists, and participant dyads. Four dyads completed an AoP@Home program during the study period. All participants with dementia reported improvements in their overall health and wellbeing, and wellbeing scores improved for all carers from baseline to post-program. Implementation was feasible using existing government funding mechanisms, and programs were acceptable to all stakeholders. It is possible to deliver participatory arts programs for community-dwelling people with dementia and their family, in their home, using sustainable and available funding models. Programs such as AoP@Home should be made more accessible alongside broader allied health and care services

    Finding Our Fathers

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    We never considered how hard it was for our fathers to go to work every day, toiling away at a job they didn’t like. And even worse, seemingly having no other choices because their families were depending on them for their very existence. Growing up, our fathers did not have time for family; spending time with us was something remote from their daily life, making them a stranger in each of their perspective homes. Worse still, We were too young to understand why our fathers were not present. This essay reveals how we have attempted to make sense of the experience this distance between us and our fathers has caused in order to detoxify our individual images of our fathers. Detoxifying the image of father means recognizing that our fathers’ have been wounded as well.</p

    Steps to implementation: Understanding barriers and enablers for implementing Arts on Prescription at Home for people impacted by dementia

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    Issue addressed: Arts on Prescription at Home (AoP@Home) involves a professional artist visiting a person with dementia and their informal carer(s) in their own home to engage them in participatory art making. While there is evidence for the use of these programs, more work is needed to facilitate effective implementation. This study explored contextual barriers and enablers to implementation of AoP@Home within a real-world community aged care service. Methods: Two remote focus groups were conducted at a community aged care provider in Sydney, Australia. Key stakeholders (n = 14) were recruited, representing: people with dementia, informal (family) carers, AoP artists, service referrers and community service managers. Focus group transcripts were analysed using qualitative content analysis and mapped onto the Consolidated Framework for Implementation Research (CFIR). Outcomes were reviewed against the Expert Recommendations for Implementing Change (ERIC) strategy compilation to inform development of a tailored implementation strategy. Results: Four overarching themes described the range of barriers and enablers to AoP@Home implementation: (1) “I don't know enough about it” (awareness and engagement within the sector), (2) artists delivering programs, (3) awareness and engagement of people impacted by dementia, (4) practicalities of implementation. All five domains of the CFIR were represented across the four themes. The ERIC compilation provided a list of practical strategies for implementation of AoP@Home. Conclusions: The implementation of psychosocial interventions for people living with dementia within a community aged care service is complex and multifactorial. So what?: Organisations planning implementation should consider conducting their own pre-implementation analysis to identify context-specific strategies
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