2,303 research outputs found

    Properties of cryogenically worked materials Final report

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    Steel and cobalt-nickel alloy compression and corrosion tests after precipitation hardening at cryogenic temperatures for increased yield strength and corrosion resistanc

    Valuing Private and Public Greenspace Using Remotely Sensed Vegetation Indices

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    In a typical metropolitan area, greenspace varies substantially in its quality and extent. Remotely sensed vegetation index data is used to characterize the heterogeneity in private and public greenspace (riparian corridors) in metropolitan Tucson, Arizona. This data set enables the researcher to test if: (1) greenness is a significant determinant of house price variation in this desert city; and (2) whether there is an interaction between public and private greenspace. Private greenspace amenities can be endogenously improved by homeowners as a complement or substitute for the greenspace that is publicly provided, whereas public greenspace might be exogenous or endogenous depending on households ability to pressure the local government to protect or restore public greenspace. The results of a Hausman test indicate that endogeneity is a problem in the dataset and therefore an instrumental variable two stage least squares estimation is used. The results of this analysis indicate that homebuyers in the study area have preferences for both greener lots and greener riparian corridors and that private and public greenspace appear to be substitutes. Results are robust across multiple identification strategies designed to address potential endogeneity. The study results could have fundamental implications for the efficient use of limited water supplies in this semi-arid metropolitan area.Resource /Energy Economics and Policy,

    Do Homebuyers Care about the 'Quality' of Natural Habitats?

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    We study if homebuyers in Tucson, Arizona care about the condition of natural habitats and if they have preferences between natural and manmade habitats. Using field work data we examine whether homebuyers willingness to pay is influenced by the biological condition of the neighboring riparian habitat and how homebuyers value alternative manmade green areas, specifically golf courses. We also explore the relationship between the field data and remote sensing vegetation indices. The results of a hedonic analysis of houses that sold within 0.2 miles of 51 stratified-random selected riparian survey sites in Tucson, Arizona reveals that homebuyers significantly value habitat quality and negatively value manmade park-like features. Homebuyers are willing to pay twenty percent more to live near a riparian corridor that is densely vegetated and contains more shrub and tree species, particularly species that are dependent on perennial water flow. These environmental premiums are significant, outweighing structural factors such as an additional garage or swimming pool. Likewise, proximity to a riparian habitat with low biological quality or to a golf course lowers property values.Land Economics/Use,

    How Do Homebuyers Value Different Types of Green Space?

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    It is important to understand tradeoffs in preferences for natural and constructed green space in semi-arid urban areas because these lands compete for scarce water resources. We perform a hedonic study using high resolution, remotely-sensed vegetation indices and house sales records. We find that homebuyers in the study area prefer greener lots, greener neighborhoods, and greener nearby riparian corridors, and they pay premiums for proximity to green space amenities. The findings have fundamental implications for the efficient allocation of limited water supplies between different types of green space and for native vegetation conservation in semi-arid metropolitan areas.hedonic model, locally weighted regression, spatial, open space, golf course, park, riparian, Consumer/Household Economics, Land Economics/Use,

    Properties of cryogenically worked materials Interim report

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    Cryogenically worked materials during strain hardenin

    Governing through trust: community-based link workers and parental engagement in education

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    This article seeks to further understandings of contemporary patterns of parental government. Parenting has emerged as a key policy domain in twenty-first century Britain and we explore the politicisation of family life by examining a pilot programme tasked with enhancing parental engagement in education amongst ‘hard-to-reach’ families within the white British community of a large inner-London borough. Concentrating upon the programme’s signature device – the deployment of community-based ‘link workers’ to bridge home and school – ‘governmentality’ (Foucault, 2009) is used as a theoretical lens through which to foreground the link workers’ role in governing parents. We draw on qualitative data collected from link workers, parents, and school leaders, to argue that link workers represent a mode of governmentality that privileges the instrumental use of trust to achieve strategic objectives, rather than coercive authority. The aim being to produce responsible, self-disciplined parents who act freely in accordance with normative expectations as to what constitutes ‘good’ parenting and effective parental support. As such, the article highlights the link workers’ role in (re)producing the ideal, neoliberal parent. However, governing through trust comes at the cost of being unable to firmly secure desired outcomes. We thereby conclude that this gentle art of parental government affords parents some latitude in resisting institutional agendas

    A Lemons “Mirage”: Erroneous Perceptions Of Asymmetric Information In The Market For Arizona Ranchettes

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    Owners of modest-sized,recreation-oriented ranch properties, known as “ranchettes,” appear to judge a key characteristic of the quality of their properties, the extent of vegetative “greenness,” based on their own observation,despite the greater reliability of publicly available climate data. The discrepancy between personal observation and public data is perceived erroneously by owners as reflecting an information asymmetry that favors the former. The consequence of this misperception is adverse selection: transplant owners, who are not familiar with long-term local weather patterns from direct observation, delay the sale of properties that are greener during their term of ownership. Econometric evidence is presented from the analysis of 694 ranchette sales in Yavapai County, Arizona during 1991-2000. The results demonstrate that the efficiency of the market mechanism is affected not just by the actual distribution of information on quality, but by its perceived distribution

    The Trace Fossil Zoophycos as an Indicator of Water Depth

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    A geographically widespread occurrence of the trace fossil Zoophycos is described from the Lower Mississippian Cuyahoga Formation of northeastern Ohio. Although Seilacher (1955, 1964, 1967a, 1967b) stated that Zoophycos is most common in “intermediate water depths,” numerous environmental indicators (oscillation ripple marks, large scale cross lamination, and Lingula) demonstrate that in northeastern Ohio Zoophycos flourished in shallow water which was above wave base. At present the genus encompasses too wide a ränge of morphologic variables. Detailed studies are needed in order to determine the limiting factor of the environment. Water depth does not appear to provide the answer

    Agent-Based Modeling and its Tradeoffs: An Introduction & Examples

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    Agent-based modeling is a computational dynamic modeling technique that may be less familiar to some readers. Agent-based modeling seeks to understand the behaviour of complex systems by situating agents in an environment and studying the emergent outcomes of agent-agent and agent-environment interactions. In comparison with compartmental models, agent-based models offer simpler, more scalable and flexible representation of heterogeneity, the ability to capture dynamic and static network and spatial context, and the ability to consider history of individuals within the model. In contrast, compartmental models offer faster development time with less programming required, lower computational requirements that do not scale with population, and the option for concise mathematical formulation with ordinary, delay or stochastic differential equations supporting derivation of properties of the system behaviour. In this chapter, basic characteristics of agent-based models are introduced, advantages and disadvantages of agent-based models, as compared with compartmental models, are discussed, and two example agent-based infectious disease models are reviewed
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