A Spatial Decision Support System Approach to Evaluate the Efficiency of a Meals-on-Wheels Program*     

David W. S. Wong  Judith W. Meyer 《The Professional geographer》1993,45(3):332-341

Due to limited resources, publicly funded service programs need to operate efficiently. This paper demonstrates how a Spatial Decision Support System (SDSS) can be used to evaluate and enhance the performance of an existing service delivery program. Elements critical to the efficiency of service programs are enumerated. A meals-on-wheels (MOW) program in Connecticut is used as a case study to demonstrate the utility of the SDSS approach. Practical issues related to data sources and system adoption are discussed.  相似文献   

Globalizing urban resilience     

Helga Leitner  Eric Sheppard  Sophie Webber  Emma Colven 《Urban geography》2018,39(8):1276-1284

Urban resilience, a new urban development and governance agenda, is being rolled out from the top down by a network of public, private, non-profit sector actors forming a global urban resilience complex: producing norms that circulate globally, creating assessment tools rendering urban resilience technical and managerial, and commodifying urban resilience such that private sector involvement becomes integral to urban development planning and governance. The Rockefeller Foundation's 100 Resilience Cities Program is at the center of this complex, working with the World Bank, global consultants, NGOs, and private sector service providers to enroll cities, develop and circulate urban resilience assessment tools, and create a market catalyzed by the notion of a resilience dividend. Notwithstanding the claim of this program being open and inclusive, aspects of its initial operationalization in Jakarta suggest that urban resilience assessment tools preempt alternative understandings of urban resilience and marginalizing voices of the city's most vulnerable populations.  相似文献   

“The mangrove preserves life”: Habitat of African survival in the Atlantic world          下载免费PDF全文

Judith Carney 《Geographical review》2017,107(3):433-451

Mangroves emerged a crucial habitat for Africans and their descendants during the transatlantic slave trade. Europeans avoided mangroves because of the deadly fevers that frequently claimed the lives of those who ventured there. Many were felled by lethal falciparum malaria, against which Africans alone carried genetic resistance. The transatlantic slave trade spread the disease‐causing plasmodium to New World Anopheles mosquitoes through infected bloodstreams, extending African mangroves’ pestilential reputation to the Neotropics. On both sides of the Atlantic, an environment Europeans feared provided Africans food, basic necessities, and sometimes, refuge from slavery. In Neotropical mangroves Africans largely replaced declining Amerindian populations, who were also immunologically vulnerable to the introduced plasmodium. Today, African descendants in Old and New World mangroves demonstrate longstanding human use of this ecosystem. Comparison of shellfish gathering and gendered collection patterns in mangroves recognizes Amerindian and African influences in Neotropical mangroves and illuminates the connections to transatlantic diasporic history. The discussion considers how a more‐than‐human geography shaped “place‐based knowledge” of mangrove swamplands that remained marginal to European territorializing during the colonial period. African and Afro‐descendant place‐making underscores the ways people, plants, insects, microbes, shellfish, and tides framed geography and diasporic identity at the periphery of the Atlantic world.  相似文献   

“Grey swan” storm surges pose a greater coastal flood hazard than climate change     

Horsburgh  Kevin  Haigh  Ivan D.  Williams  Jane  De Dominicis  Michela  Wolf  Judith  Inayatillah  Addina  Byrne  David 《Ocean Dynamics》2021,71(6-7):715-730

Ocean Dynamics - In this paper, we show that over the next few decades, the natural variability of mid-latitude storm systems is likely to be a more important driver of coastal extreme sea levels...  相似文献   

The role of knowledge in students’ flood-risk perception     

Bosschaart  Adwin  Kuiper  Wilmad  van der Schee  Joop  Schoonenboom  Judith 《Natural Hazards》2013,69(3):1661-1680

Natural Hazards - Until now, flood-risk perception in the Netherlands has been solely studied as it relates to adults. This exploratory study focused on 15-year-old students who have taken...  相似文献   

Radio-colouration of diamond: a spectroscopic study     

Lutz Nasdala  Dieter Grambole  Manfred Wildner  Alexander M. Gigler  Thomas Hainschwang  Alexander M. Zaitsev  Jeffrey W. Harris  Judith Milledge  Daniel J. Schulze  Wolfgang Hofmeister  Walter A. Balmer 《Contributions to Mineralogy and Petrology》2013,165(5):843-861

We have undertaken a study of the common green or orange-brown spots at the surface of rough diamond specimens, which are caused by alpha particles emanating from radioactive sources outside the diamond. Richly coloured haloes represent elevated levels of structural damage, indicated by strong broadening of the main Raman band of diamond, intense strain birefringence, and up-doming of spots due to their extensive volume expansion. Green radio-colouration was analogously generated through the irradiation of diamond with 8.8 MeV helium ions. The generation of readily visible radio-colouration was observed after irradiating diamond with ≥10¹⁵ He ions per cm². The accumulation of such a high number of alpha particles requires irradiation of the diamond from a radioactive source over long periods of time, presumably hundreds of millions of years in many cases. In the samples irradiated with He ions, amorphisation was observed in volume areas where the defect density exceeded 5 × 10^?3 Å^?3 (or 0.03 dpa; displacements per target atom). In contrast, graphitisation as a direct result of the ion irradiation was not observed. The green colouration transformed to brown at moderate annealing temperatures (here 450 °C). The colour transformation is associated with only partial recovery of the radiation damage. The colour change is mainly due to the destruction of the GR1 centre, explained by trapping of vacancies at A defects to form the H3 centre. An activation energy of ~2.4 ± 0.2 eV was determined for the GR1 reduction. The H3 centre, in turn, causes intense yellowish-green photoluminescence under ultraviolet illumination. Radio-colouration and associated H3 photoluminescence are due to point defects created by the ions irradiated, whereas lattice ionisation is of minor importance. This is concluded from the depth distribution of the colouration and the photoluminescence intensity (which corresponds to the defect density but not the ionisation distribution pattern). The effect of the implanted He ions themselves on the colour and photoluminescence seems to be negligible, as radio-colouration and H3 emission were analogously produced through irradiation of diamond with C ions. The photoluminescence emission becomes observable at extremely low defect densities on the order of 10^?6 Å^?3 (or 0.000006 dpa) and is suppressed at moderate defect densities of ~5 × 10^?4 Å^?3 (or ~0.003 dpa). Intensely brown-coloured diamond hence does not show the H3 emission anymore. Anneals up to 1,600 °C has reduced considerably irradiation damage and radio-colouration, but the structural reconstitution of the diamond (and its de-colouration) was still incomplete.  相似文献   

Address databases for national SDI: Comparing the novel data grid approach to data harvesting and federated databases     

Serena Coetzee  Judith Bishop 《International journal of geographical information science》2013,27(9):1179-1209

The original purpose of addresses was to enable the correct and unambiguous delivery of postal mail. The advent of computers and more specifically geographic information systems (GIS) opened up a whole new range of possibilities for the use of addresses, such as routing and vehicle navigation, spatial demographic analysis, geo‐marketing, and service placement and delivery. Such functionality requires a database which can store and access spatial data effectively. In this paper we present address databases and justify the need for national address databases. We describe models used for national address databases, and present our evaluation framework for an address database at a national level within the context of a spatial data infrastructure (SDI). The models of data harvesting, federated databases and data grids are analyzed and evaluated according to our novel framework, and we show that the data grid model has some unique features that make it attractive for a national address database in an environment where centralized control and/or coordination is difficult or undesirable.  相似文献   

Micrometeoroid impact crater statistics at the boundary of Earth's gravitational sphere of influence     

Stanley G. Love  Judith H. Allton 《Icarus》2006,184(2):302-307

We surveyed craters on a space-exposed surface from the Genesis solar wind sample return mission to find new constraints on the population of micrometeoroids at the edge of the Earth's gravitational sphere of influence. The target was made of 6061-T6 aluminum, identical to the composition of the space-facing end of the Long Duration Exposure Facility satellite, which recorded micrometeoroid impacts in low Earth orbit. We use data from both locations to compare crater frequency as a function of size, with and without gravitational focussing by the Earth. We find that the cratering flux near the Earth-Sun L1 libration point is indistinguishable, within the ∼40% uncertainty of this study, from that in low Earth orbit. The small degree of gravitational focussing between the two locations indicates that particles with geocentric free-space velocities less than a few kilometers per second comprise no more than a few percent of the interplanetary dust complex.  相似文献   

Managing Bay and Estuarine Ecosystems for Multiple Services     

Lisa A. Needles  Sarah E. Lester  Richard Ambrose  Anders Andren  Marc Beyeler  Michael S. Connor  James E. Eckman  Barry A. Costa-Pierce  Steven D. Gaines  Kevin D. Lafferty  Hunter S. Lenihan  Julia Parrish  Mark S. Peterson  Amy E. Scaroni  Judith S. Weis  Dean E. Wendt 《Estuaries and Coasts》2015,38(1):35-48

Managers are moving from a model of managing individual sectors, human activities, or ecosystem services to an ecosystem-based management (EBM) approach which attempts to balance the range of services provided by ecosystems. Applying EBM is often difficult due to inherent tradeoffs in managing for different services. This challenge particularly holds for estuarine systems, which have been heavily altered in most regions and are often subject to intense management interventions. Estuarine managers can often choose among a range of management tactics to enhance a particular service; although some management actions will result in strong tradeoffs, others may enhance multiple services simultaneously. Management of estuarine ecosystems could be improved by distinguishing between optimal management actions for enhancing multiple services and those that have severe tradeoffs. This requires a framework that evaluates tradeoff scenarios and identifies management actions likely to benefit multiple services. We created a management action-services matrix as a first step towards assessing tradeoffs and providing managers with a decision support tool. We found that management actions that restored or enhanced natural vegetation (e.g., salt marsh and mangroves) and some shellfish (particularly oysters and oyster reef habitat) benefited multiple services. In contrast, management actions such as desalination, salt pond creation, sand mining, and large container shipping had large net negative effects on several of the other services considered in the matrix. Our framework provides resource managers a simple way to inform EBM decisions and can also be used as a first step in more sophisticated approaches that model service delivery.  相似文献   

Using Polar Coronal Hole Area Measurements to Determine the Solar Polar Magnetic Field Reversal in Solar Cycle 24     

N. Karna  S. A. Hess Webber  W. D. Pesnell 《Solar physics》2014,289(9):3381-3390

An analysis of solar polar coronal hole (PCH) areas since the launch of the Solar Dynamics Observatory (SDO) shows how the polar regions have evolved during Solar Cycle 24. We present PCH areas from mid-2010 through 2013 using data from the Atmospheric Imager Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) instruments onboard SDO. Our analysis shows that both the northern and southern PCH areas have decreased significantly in size since 2010. Linear fits to the areas derived from the magnetic-field properties indicate that, although the northern hemisphere went through polar-field reversal and reached solar-maximum conditions in mid-2012, the southern hemisphere had not reached solar-maximum conditions in the polar regions by the end of 2013. Our results show that solar-maximum conditions in each hemisphere, as measured by the area of the polar coronal holes and polar magnetic field, will be offset in time.  相似文献