A Service Oriented Geoprocessing System for Real‐Time Road Traffic Monitoring     

Aengus McCullough  Philip James  Stuart Barr 《Transactions in GIS》2011,15(5):651-665

The emergence of the Sensor Web has paved the way for a new set of innovative software applications that exploit the enhanced availability of real‐time information. This article describes one such application built from Sensor Web components that aggregates GPS track data from a fleet of vehicles to provide an overview of road traffic congestion at the city scale. The application embodies a Service Oriented Architecture; web service components are used to archive and pre‐process incoming sensor observations, to encapsulate a horizontally partitioned spatial database that performs geoprocessing, and to disseminate results to client applications. Our results confirm that floating car data can provide an accurate depiction of current road traffic conditions. The presented solution uses Open Geospatial Consortium web services where possible and serves to highlight the difficulties inherent in achieving horizontal database scalability in sensor based geoprocessing systems.  相似文献   

Geodemographics as a tool for targeting neighbourhoods in public health campaigns   总被引：2，自引：1，他引：1  

Jakob Petersen  Maurizio Gibin  Paul Longley  Pablo Mateos  Philip Atkinson  David Ashby 《Journal of Geographical Systems》2011,13(2):173-192

Geodemographics offers the prospects of integrating, modelling and mapping health care needs and other health indicators that are useful for targeting neighbourhoods in public health campaigns. Yet reports about this application domain has to date been sporadic. The purpose of this paper is to examine the potential of a bespoke geodemographic system for neighbourhood targeting in an inner city public health authority, Southwark Primary Care Trust, London. This system, the London Output Area Classification (LOAC), is compared to six other geodemographic systems from both governmental and commercial sources. The paper proposes two new indicators for assessing the performance of geodemographic systems for neighbourhood targeting based on local hospital demand data. The paper also analyses and discusses the utility of age- and sex standardisation of geodemographic profiles of health care demand.  相似文献   

Heterogeneous accretion,composition and core–mantle differentiation of the Earth     

David C. Rubie  Daniel J. Frost  Ute Mann  Yuki Asahara  Francis Nimmo  Kyusei Tsuno  Philip Kegler  Astrid Holzheid  Herbert Palme 《Earth and Planetary Science Letters》2011,301(1-2):31-42

A model of core formation is presented that involves the Earth accreting heterogeneously through a series of impacts with smaller differentiated bodies. Each collision results in the impactor's metallic core reacting with a magma ocean before merging with the Earth's proto-core. The bulk compositions of accreting planetesimals are represented by average solar system abundances of non-volatile elements (i.e. CI-chondritic), with 22% enhancement of refractory elements and oxygen contents that are defined mainly by the Fe metal/FeO silicate ratio. Based on an anhydrous bulk chemistry, the compositions of coexisting core-forming metallic liquid and peridotitic silicate liquid are calculated by mass balance using experimentally-determined metal/silicate partition coefficients for the elements Fe, Si, O, Ni, Co, W, Nb, V, Ta and Cr. Oxygen fugacity is fixed by the partitioning of Fe between metal and silicate and depends on temperature, pressure and the oxygen content of the starting composition. Model parameters are determined by fitting the calculated mantle composition to the primitive mantle composition using least squares minimization. Models that involve homogeneous accretion or single-stage core formation do not provide acceptable fits. In the most successful models, involving 24 impacting bodies, the initial 60–70% (by mass) of the Earth accretes from highly-reduced material with the final 30–40% of accreted mass being more oxidised, which is consistent with results of dynamical accretion simulations. In order to obtain satisfactory fits for Ni, Co and W, it is required that the larger (and later) impactor cores fail to equilibrate completely before merging with the Earth's proto-core, as proposed previously on the basis of Hf-W isotopic studies. Estimated equilibration conditions may be consistent with magma oceans extending to the core–mantle boundary, thus making core formation extremely efficient. The model enables the compositional evolution of the Earth's mantle and core to be predicted throughout the course of accretion. The results are consistent with the late accretion of the Earth's water inventory, possibly with a late veneer after core formation was complete. Finally, the core is predicted to contain ~ 5 wt.% Ni, ~ 8 wt.% Si, ~ 2 wt.% S and ~ 0.5 wt.% O.  相似文献   

Public perception of climate change and disaster preparedness: Evidence from the Philippines     

Vincenzo Bollettino  Tilly Alcayna-Stevens  Manasi Sharma  Philip Dy  Phuong Pham  Patrick Vinck 《Chemie der Erde / Geochemistry》2011

The Philippines is highly susceptible to both geophysical and climate-related disasters. This article explores Filipinos knowledge and perception of climate change and their association with what action Filipinos take to prepare for rapid onset natural hazards such as typhoons. Data for this study were collected from a nationally representative random survey of 5,184 adults conducted between March and April of 2017. Filipinos self-report relatively low levels of knowledge of climate change and cited increased temperatures, shifts in seasons, and heavier rains as the most likely consequences. Levels of disaster preparedness in the Philippines differ widely by region. Although most Filipinos perceive that natural hazards are a risk to them, only a third of Filipinos undertake measures to prepare for disasters. Filipinos who perceive climate-related changes directly impacting their households report taking greater action to prepare for disasters. Filipinos who believe they have been directly impacted by climate-related changes are also more likely to prepare for disasters, take planning actions, and undertake material actions to prepare, such as dwelling improvements. Other factors associated with disaster preparedness include gender, membership in an association, wealth, risk perception, and prior exposure to and losses due to disasters. The findings imply that, while posing different challenges and requiring different responses, adaptation to climate change and disaster preparedness are inherently associated and potentially mutually reinforcing. Policies and programs would arguably benefit from a more unified intervention framework that links climate change adaptation and disaster preparedness.  相似文献   

Impacts of paleohydrological changes on n-alkane biomarker compositions of a Holocene peat sequence in the eastern European Russian Arctic     

Rina A. Andersson  Peter Kuhry  Philip Meyers  Yngve Zebühr  Patrick Crill  Magnus Mörth 《Organic Geochemistry》2011,42(9):1065-1075

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Modelling tide–surge interaction effects using finite volume and finite element models of the Irish Sea     

Jiuxing?XingEmail author  Eric?Jones  Alan?M.?Davies  Philip?Hall 《Ocean Dynamics》2011,61(8):1137-1174

An unstructured mesh model of the west coast of Britain, covering the same domain and using topography and open boundary forcing that are identical to a previous validated uniform grid finite difference model of the region, is used to compare the performance of a finite volume (FV) and a finite element (FE) model of the area in determining tide–surge interaction in the region. Initial calculations show that although qualitatively both models give comparable tidal solutions in the region, comparison with observations shows that the FV model tends to under-estimate tidal amplitudes and hence background tidal friction in the eastern Irish Sea. Storm surge elevations in the eastern Irish Sea due to westerly, northerly and southerly uniform wind stresses computed with the FV model tend to be slightly higher than those computed with the FE model, due to differences in background tidal friction. However, both models showed comparable non-linear tide–surge interaction effects for all wind directions, suggesting that they can reproduce the extensive tide–surge interaction processes that occur in the eastern Irish Sea. Following on from this model comparison study, the physical processes contributing to surge generation and tide–surge interaction in the region are examined. Calculations are performed with uniform wind stresses from a range of directions, and the balance of various terms in the hydrodynamic equations is examined. A detailed comparison of the spatial variability of time series of non-linear bottom friction and non-linear momentum advection terms at six adjacent nodes at two locations in water depths of 20 and 6 m showed some spatial variability from one node to another. This suggests that even in the near coastal region, where water depths are of the order of 6 m and the mesh is fine (of order 0.5 km), there is significant spatial variability in the non-linear terms. In addition, distributions of maximum bed stress due to tides and wind forcing in nearshore regions show appreciable spatial variability. This suggests that intensive measurement campaigns and very high-resolution mesh models are required to validate and reproduce the non-linear processes that occur in these regions and to predict extreme bed stresses that can give rise to sediment movement. High-resolution meshes will also be required in pollution transport problems.  相似文献   

Variations of Li and Mg isotope ratios in bulk chondrites and mantle xenoliths   总被引：4，自引：0，他引：4  

Philip A.E. Pogge von Strandmann  Tim Elliott  Chris Coath  Alistair B. Jeffcoate 《Geochimica et cosmochimica acta》2011,75(18):5247-5268

We present whole rock Li and Mg isotope analyses of 33 ultramafic xenoliths from the terrestrial mantle, which we compare with analyses of 30 (mostly chondritic) meteorites. The accuracy of our new Mg isotope ratio measurement protocol is substantiated by a combination of standard addition experiments, the absence of mass independent effects in terrestrial samples and our obtaining identical values for rock standards using two different separation chemistries and three different mass-spectrometric introduction systems. Carbonaceous, ordinary and enstatite chondrites have irresolvable mean stable Mg isotopic compositions (δ²⁵Mg = −0.14 ± 0.06; δ²⁶Mg = −0.27 ± 0.12‰, 2SD), but our enstatite chondrite samples have lighter δ⁷Li (by up to ∼3‰) than our mean carbonaceous and ordinary chondrites (3.0 ± 1.5‰, 2SD), possibly as a result of spallation in the early solar system. Measurements of equilibrated, fertile peridotites give mean values of δ⁷Li = 3.5 ± 0.5‰, δ²⁵Mg = −0.10 ± 0.03‰ and δ²⁶Mg = −0.21 ± 0.07‰. We believe these values provide a useful estimate of the primitive mantle and they are within error of our average of bulk carbonaceous and ordinary chondrites. A fuller range of fresh, terrestrial, ultramafic samples, covering a variety of geological histories, show a broad positive correlation between bulk δ⁷Li and δ²⁶Mg, which vary from −3.7‰ to +14.5‰, and −0.36‰ to + 0.06‰, respectively. Values of δ⁷Li and δ²⁶Mg lower than our estimate of primitive mantle are strongly linked to kinetic isotope fractionation, occurring during transport of the mantle xenoliths. We suggest Mg and Li diffusion into the xenoliths is coupled to H loss from nominally anhydrous minerals following degassing. Diffusion models suggest that the co-variation of Mg and Li isotopes requires comparable diffusivities of Li and Mg in olivine. The isotopically lightest samples require ∼5-10 years of diffusive ingress, which we interpret as a time since volatile loss in the host magma. Xenoliths erupted in pyroclastic flows appear to have retained their mantle isotope ratios, likely as a result of little prior degassing in these explosive events. High δ⁷Li, coupled with high [Li], in rapidly cooled arc peridotites may indicate that these samples represent fragments of mantle wedge that has been metasomatised by heavy, slab-derived fluids. If such material is typically stirred back into the convecting mantle, it may account for the heavy δ⁷Li seen in some oceanic basalts.  相似文献   

Geochemical evolution of uraniferous soda lakes in Eastern Mongolia   总被引：1，自引：1，他引：0  

Benjamin S. Linhoff  Philip C. Bennett  Tamir Puntsag  Ochir Gerel 《Environmental Earth Sciences》2011,62(1):171-183

Extremely high concentrations of uranium (U) were discovered in shallow, groundwater-fed hyperalkaline soda lakes in Eastern Mongolia. A representative groundwater sample in this area is dilute and alkaline, pH = 7.9, with 10 mM TIC and 5 mM Cl⁻. In contrast, a representative lake water sample is pH ~ 10 with TIC and Cl⁻ each more than 1,000 mM. Groundwater concentrations of U range from 0.03 to 0.43 μM L⁻¹. Lake water U ranges from 0.24 to >62.5 μM, possibly the highest naturally occurring U concentrations ever reported in surface water. Strontium isotopes ⁸⁷Sr/⁸⁶Sr varied in groundwaters from 0.706192 to 0.709776 and in lakes ⁸⁷Sr/⁸⁶Sr varied from 0.708702 to 0.709432. High concentrations of U, Na, Cl⁻, and K correlate to radiogenic Sr in lake waters suggesting that U is sourced from local Cretaceous alkaline rhyolites. Uranium-rich groundwaters are concentrated by evaporation and U(VI) is chelated by CO₃⁻² to form the highly soluble UO₂(CO₃)₃⁻⁴. Modeled evaporation of lakes suggests that a U-mineral phase is likely to precipitate during evaporation.  相似文献   

Application of primary haemocyte culture of Penaeus monodon in the assessment of cytotoxicity and genotoxicity of heavy metals and pesticides   总被引：1，自引：0，他引：1  

Jose S  Jayesh P  Mohandas A  Philip R  Bright Singh IS 《Marine environmental research》2011,71(3):169-177

Lack of shrimp cell lines has hindered the study of pollutants which adversely affects shrimp health and its export value. In this context a primary haemocyte culture developed from Penaeus monodon was employed for assessing the cytotoxicity and genotoxicity of two heavy metal compounds, cadmium chloride and mercuric chloride and two organophosphate insecticides, malathion and monocrotophos. Using MTT assay 12?h IC(50) values calculated were 31.09?±?16.27?μM and 5.52?±?1.16?μM for cadmium chloride and mercuric chloride and 59.94?±?52.30?mg?l(-1) and 186.76?±?77.00?mg?l(-1) for malathion and monocrotophos respectively. Employing Comet assay, DNA damage inflicted by these pollutants on haemocytes were evaluated and the pollutants induced DNA damage in >60% of the cells. The study suggested that haemocyte culture could be used as a tool for quantifying cytotoxicity and genotoxicity of aquaculture drugs, management chemicals and pollutants.  相似文献   

An explicit finite difference model for simulating weakly nonlinear and weakly dispersive waves over slowly varying water depth   总被引：2，自引：0，他引：2  

Xiaoming Wang  Philip L.-F. Liu 《Coastal Engineering》2011

In this paper, a modified leap-frog finite difference (FD) scheme is developed to solve Non linear Shallow Water Equations (NSWE). By adjusting the FD mesh system and modifying the leap-frog algorithm, numerical dispersion is manipulated to mimic physical frequency dispersion for water wave propagation. The resulting numerical scheme is suitable for weakly nonlinear and weakly dispersive waves propagating over a slowly varying water depth. Numerical studies demonstrate that the results of the new numerical scheme agree well with those obtained by directly solving Boussinesq-type models for both long distance propagation, shoaling and re-fraction over a slowly varying bathymetry. Most importantly, the new algorithm is much more computationally efficient than existing Boussinesq-type models, making it an excellent alternative tool for simulating tsunami waves when the frequency dispersion needs to be considered.  相似文献