2,430 research outputs found

    Optimising the location of antenatal classes

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    Objectives: To combine micro simulation and location-allocation techniques to determine antenatal class locations which minimise the distance travelled from home by potential users. Design: Micro simulation modelling and location-allocation modeling. Setting: City of Leeds, U.K. Participants: Potential users of antenatal classes. Methods: An individual-level micro simulation model was built to estimate the number of births for small areas by combining data from the UK Census 2001 and the Health Survey for England 2006. Using this model as a proxy for service demand, we then used a location-allocation model to optimize locations. Findings: Different scenarios show the advantage of combining these methods to optimize (re)locating antenatal classes and therefore reduce inequalities in accessing services for pregnant women. Key Conclusions: Use of these techniques should lead to better use of resources by allowing planners to identifyoptimal locations of antenatal classes which minimise women’s travel. Implications for practice: These results are especially important for health-care planners tasked with the difficult issue of targeting scarce resources in a cost-efficient, but also effective or accessible, manner

    The complexity of pluralistic ignorance in Republican climate change policy support in the United States

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    Most Americans fail to recognize widespread public support for climate change action. Here we investigate how this phenomenon differs for Republican supporters versus opponents of several climate change policies. Surveying a representative sample of Republican voters (N = 1000), we find that misperception of in-group support for climate action is primarily restricted to Republicans already opposed to action. Specifically, those in the minority (i.e., Republicans opposed to climate action) were more likely to erroneously perceive other Republicans as holding views on climate change policy similar to their own. While Republican supporters recognize that most Republicans support climate change policy, they may be discouraged from expressing their support due to an information environment disproportionately portraying Republicans as opposed to climate change action

    Remarks on evolution of space-times in 3+1 and 4+1 dimensions

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    A large class of vacuum space-times is constructed in dimension 4+1 from hyperboloidal initial data sets which are not small perturbations of empty space data. These space-times are future geodesically complete, smooth up to their future null infinity, and extend as vacuum space-times through their Cauchy horizon. Dimensional reduction gives non-vacuum space-times with the same properties in 3+1 dimensions.Comment: 10pp, exposition improved; final versio

    The crime drop and the security hypothesis

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    Major crime drops were experienced in the United States and most other industrialised countries for a decade from the early to mid-1990s. Yet there is little agreement over explanation or lessons for policy. Here it is proposed that change in the quantity and quality of security was a key driver of the crime drop. From evidence relating to vehicle theft in two countries it is concluded that electronic immobilisers and central locking were particularly effective. It is suggested that reduced car theft may have induced drops in other crime including violence. From this platform a broader security hypothesis, linked to routine activity and opportunity theory, is outlined

    A Theory of Sampling for Continuous-time Metric Temporal Logic

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    This paper revisits the classical notion of sampling in the setting of real-time temporal logics for the modeling and analysis of systems. The relationship between the satisfiability of Metric Temporal Logic (MTL) formulas over continuous-time models and over discrete-time models is studied. It is shown to what extent discrete-time sequences obtained by sampling continuous-time signals capture the semantics of MTL formulas over the two time domains. The main results apply to "flat" formulas that do not nest temporal operators and can be applied to the problem of reducing the verification problem for MTL over continuous-time models to the same problem over discrete-time, resulting in an automated partial practically-efficient discretization technique.Comment: Revised version, 43 pages

    The eventization of leisure and the strange death of alternative Leeds

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    The communicative potential of city spaces as leisure spaces is a central assumption of political activism and the creation of alternative, counter-cultural and subcultural scenes. However, such potential for city spaces is limited by the gentrification, privatization and eventization of city centres in the wake of wider societal and cultural struggles over leisure, work and identity formation. In this paper, we present research on alternative scenes in the city of Leeds to argue that the eventization of the city centre has led to a marginalization and of alternative scenes on the fringes of the city. Such marginalization has not caused the death of alternative Leeds or political activism associated with those scenes—but it has changed the leisure spaces (physical, political and social) in which alternative scenes contest the mainstream

    Stellar Companions to Stars with Planets

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    A combination of high-resolution and wide-field imaging reveals two binary stars and one triple star system among the sample of the first 11 stars with planets detected by radial velocity variations. High resolution speckle or adaptive optics (AO) data probe subarcsecond scales down to the diffraction limit of the Keck 10-m or Lick 3-m, and direct images or AO images are sensitive to a wider field, extending to 10" or 38", depending upon the camera. One of the binary systems -- HD 114762 -- was not previously known to be a spatially resolved multiple system; additional data taken with the combination of Keck adaptive optics and NIRSPEC are used to characterize the new companion. The second binary system -- Tau Boo -- was a known multiple with two conflicting orbital solutions; the current data will help constrain the discrepant estimates of periastron time and separation. Another target -- 16 Cyg B -- was a known common proper motion binary, but the current data resolve a new third component, close to the wide companion 16 Cyg A. Both the HD 114762 and 16 Cyg B systems harbor planets in eccentric orbits, while the Tau Boo binary contains an extremely close planet in a tidally-circularized orbit. Although the sample is currently small, the proportion of binary systems is comparable to that measured in the field over a similar separation range. Incorporating the null result from another companion search project lowers the overall fraction of planets in binary systems, but the detections in our survey reveal that planets can form in binaries separated by less than 50 AU.Comment: 5 Tables, 16 Figures. ApJ, accepte

    Air transport liberalisation and airport dependency: developing a composite index

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    Air transport liberalisation in Europe has produced some major changes to the networks operated by airlines and the services available at airports. Within this context the degree of airport dependency in terms of market, spatial and temporal concentration is important to know from an economic geography and risk management perspective. A composite index called the Airport Dependency Index (ADI) is developed to measure airport dependency based on the concept of the relative Gini coefficient. Liberalisation has had varying impacts depending on the size and type of airport and so a comparison is made of the degree of dependency at a large sample of European airports using the ADI. The ADI has the potential to provide insight on the sustainability and worthiness of financing airport projects, and on whether airports should diversify further their activities by investing in the growth and expansion of their network

    Spinaxinus (Bivalvia: Thyasiroidea) from sulfide biogenerators in the Gulf of Mexico and hydrothermal vents in the Fiji Back Arc: Chemosymbiosis and Taxonomy

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    Two new species of the thyasirid genus Spinaxinus (S. emicatus Oliver n. sp. and S. phrixicus Oliver n. sp.) are described from the Gulf of Mexico and the southwest Pacific, respectively. Both are compared with the type species of the genus, the eastern Atlantic S. sentosus Oliver and Holmes, 2006. Living specimens from the Gulf of Mexico were retrieved from artificial sulfide bio-generators on the upper Louisiana Slope. Gill morphology and molecular markers from the symbiotic bacteria confirm that Spinaxinus is chemosynthetic and that the chemoautotrophic bacteria are related to sulfide oxidizing Gammaproteobacteria. Living specimens from the southwest Pacific were retrieved from hydrothermal vent sites in the Fiji and Lau Back Arc Basins. In the Atlantic Spinaxinus is now recorded from two anthropogenic situations and appears to be generally absent from natural cold seep sites and not yet recorded at any hydrothermal sites. The primarily anthropogenic distribution of Spinaxinus in the Atlantic is discussed with reference to the natural hydrothermal vent habitat of the Pacific S. phrixicus.Spinaxinus (Bivalvia: Thyasiroidea) de bio-generadores artificiales de sulfuro situados en el Golfo de Méjico y en fuentes hidrotermales de las Islas Fiji: quimiosimbiosis y taxonomía. – En este trabajo se describen dos especies nuevas de tisárido del género Spinaxinus (S. emcatus Oliver n. sp. y S. phrixicus Oliver n. sp.) encontradas res- pectivamente en el Golfo de Méjico y en el sureste del Pacífico. Se comparan estas dos especies nuevas con la especie tipo del género, S. sentous Oliver y Holmes, 2006 descrita en el Este del Atlántico. Para describir estas dos especies, se observaron ejemplares vivos recolectados sobre bio-generadores artificiales de sulfuro situados en la parte alta de la plataforma conti- nental de Louisiana, en el Golfo de Méjico. Las observaciones realizadas de las branquias de Spinaxinus y la caracterización genética de las bacterias simbiontes en estos ejemplares confirmaron que Spinaxinus es un género quimiosintético que con- tiene bacterias quimioautótrofas cercanas a las Gammaproteobacterias responsables de la oxidación del sulfuro. También se recolectaron ejemplares vivos de fuentes hidrotermales situadas en las Islas Fiji y en ‘Lau Back Arc Basins’ ambas localiza- das en el Pacífico suroccidental. La especie atlántica de Spinaxinus se encontró en dos tipos de sustratos artificiales mientras que parece que esta especie no se encuentra en ambientes naturales equivalentes como serían las surgencias frías y las fuentes hidrotermales. La distribución aparentemente limitada de la especie atlántica se discute en relación con la distribución de S. phrixicus en las fuentes hidrotermales del Pacífico
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