Commodifying poverty: gentrification and consumption in Vancouver’s Downtown Eastside     

Katherine Burnett 《Urban geography》2013,34(2):157-176

The Downtown Eastside of Vancouver, British Columbia, remains one of the poorest neighborhoods in Canada, yet is also a site of rapid gentrification. Both new and revitalized restaurants have created new spaces of consumption, transforming the neighborhood into a dining destination. Site visits and an analysis of the discourses used in newspaper articles and magazine features, as well as on blogs and in other online spaces, indicate that the presence of poor and marginalized residents of the Downtown Eastside is one of the reasons for some consumers’ decisions to visit new upscale establishments in the area. Analysis of advertisements and other primary documents indicates that the presence of poor and marginalized residents has become a competitive niche for the promotion of distinctive and authentic culinary adventures. This trend toward poverty tourism signals a shift from the simple displacement of low-income residents to a more complex form of gentrification in which residents face spatial management and control while their poverty is commodified.  相似文献   

The politics of the encounter: urban theory and protest under planetary urbanization,by Andy Merrifield     

Katherine Burnett 《Urban geography》2013,34(3):457-458

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Geochemical mapping using stream sediments in west-central Nigeria: Implications for environmental studies and mineral exploration in West Africa     

Dan J. Lapworth  Katherine V. Knights  Roger M. Key  Christopher C. Johnson  Emmanuel Ayoade  Michael A. Adekanmi  Tunde M. Arisekola  Olugbenga A. Okunlola  Birgitta Backman  Mikael Eklund  Paul A. Everett  Robert T. Lister  John Ridgway  Michael J. Watts  Simon J. Kemp  Peter E.J. Pitfield 《Applied Geochemistry》2012

This paper provides an overview of regional geochemical mapping using stream sediments from central and south-western Nigeria. A total of 1569 stream sediment samples were collected and 54 major and trace elements determined by ICP-MS and Au, Pd and Pt by fire assay. Multivariate statistical techniques (e.g., correlation analysis and principal factor analysis) were used to explore the data, following appropriate data transformation, to understand the data structure, investigate underlying processes controlling spatial geochemical variability and identify element associations. Major geochemical variations are controlled by source geology and provenance, as well as chemical weathering and winnowing processes, more subtle variations are a result of land use and contamination from anthropogenic activity.  相似文献   

Effect of groundwater pH and ionic strength on strontium sorption in aquifer sediments: Implications for Sr mobility at contaminated nuclear sites     

Sarah H. Wallace  Samuel Shaw  Katherine Morris  Joe S. Small  Adam J. Fuller  Ian T. Burke 《Applied Geochemistry》2012

Strontium-90 is a beta emitting radionuclide produced during nuclear fission, and is a problem contaminant at many nuclear facilities. Transport of ⁹⁰Sr in groundwaters is primarily controlled by sorption reactions with aquifer sediments. The extent of sorption is controlled by the geochemistry of the groundwater and sediment mineralogy. Here, batch sorption experiments were used to examine the sorption behaviour of ⁹⁰Sr in sediment–water systems representative of the UK Sellafield nuclear site based on groundwater and contaminant fluid compositions. In experiments with low ionic strength groundwaters (<0.01 mol L⁻¹), pH variation is the main control on sorption. The sorption edge for ⁹⁰Sr was observed between pH 4 and 6 with maximum sorption occurring (K_d ∼ 10³ L kg⁻¹) at pH 6–8. At ionic strengths above 10 mmol L⁻¹, and at pH values between 6 and 8, cation exchange processes reduced ⁹⁰Sr uptake to the sediment. This exchange process explains the lower ⁹⁰Sr sorption (K_d ∼ 40 L kg⁻¹) in the presence of artificial Magnox tank liquor (IS = 29 mmol L⁻¹). Strontium K-edge EXAFS spectra collected from sediments incubated with Sr²⁺ in either HCO₃-buffered groundwater or artificial Magnox tank liquor, revealed a coordination environment of ∼9 O atoms at 2.58–2.61 Å after 10 days. This is equivalent to the Sr²⁺ hydration sphere for the aqueous ion and indicates that Sr occurs primarily in outer sphere sorption complexes. No change was observed in the Sr sorption environment with EXAFS analysis after 365 days incubation. Sequential extractions performed on sediments after 365 days also found that ∼80% of solid associated ⁹⁰Sr was exchangeable with 1 M MgCl₂ in all experiments. These results suggest that over long periods, ⁹⁰Sr in contaminated sediments will remain primarily in weakly bound surface complexes. Therefore, if groundwater ionic strength increases (e.g. by saline intrusion related to sea level rise or by design during site remediation) then substantial remobilisation of ⁹⁰Sr is to be expected.  相似文献   

Community respiration of decomposing plants in Oregon estuarine marshes     

John L. Gallagher  Harold V. Kibby  Katherine W. Skirvin 《Estuarine, Coastal and Shelf Science》1984,18(4):421-431

Community respiration rates in air and water were measured as indicators of the decomposition rate of dead plant tissue from nine stands of plants in two Oregon estuarine marshes. Respiration rates were low and relatively constant from November to February; during warmer periods several patterns emerged. The highest respiration rates for the most and least active communities differed up to one order of magnitude. The moisture, nitrogen, and crude fibre content, as well as plant shoot and canopy structure, appeared to be important determinants of the respiration rate. Comparisons of aerial and aquatic respiration rates for a single date may be useful for determining the recent moisture history of the tissue. Rates of dead plant community respiration in Pacific North-west marshes equalled and, in one case, exceeded those in the Atlantic South-east.  相似文献   

On the redshift cut-off for steep-spectrum radio sources   总被引：1，自引：0，他引：1  

Matt J. Jarvis  Steve Rawlings  Chris J. Willott  Katherine M. Blundell  Steve Eales  Mark Lacy 《Monthly notices of the Royal Astronomical Society》2001,327(3):907-917

We use three samples (3CRR, 6CE and 6C*) selected at low radio frequency to constrain the cosmic evolution in the radio luminosity function (RLF) for the 'most luminous' steep-spectrum radio sources. Though intrinsically rare, such sources give the largest possible baseline in redshift for the complete flux-density-limited samples currently available. Using parametric models to describe the RLF, incorporating distributions in radio spectral shape and linear size, as well as the usual luminosity and redshift, we find that the data are consistent with a constant comoving space density between     and     . We find that this model is favoured over a model with similar evolutionary behaviour to that of optically selected quasars (i.e., a roughly Gaussian distribution in redshift) with probability ratios of     and     for spatially flat cosmologies with     and     respectively. Within the uncertainties, this evolutionary behaviour may be reconciled with the shallow decline preferred for the comoving space density of flat-spectrum sources by Dunlop & Peacock and Jarvis & Rawlings, in line with the expectations of unified schemes.  相似文献   

Rates of weathering rind formation on Costa Rican basalt     

Peter B. Sak  Donald M. Fisher  Katherine Murphy 《Geochimica et cosmochimica acta》2004,68(7):1453-1472

Weathering rind thicknesses were measured on ∼ 200 basaltic clasts collected from three regionally extensive alluvial fill terraces (Qt 1, Qt 2, and Qt 3) preserved along the Pacific coast of Costa Rica. Mass balance calculations suggest that conversion of unweathered basaltic core minerals (plagioclase and augite) to authigenic minerals in the porous rind (kaolinite, allophane, gibbsite, Fe oxyhydroxides) is iso-volumetric and Ti and Zr are relatively immobile. The hierarchy of cation mobility (Ca ≈ Na > K ≈ Mg > Si > Al > Fe ≈ P) is similar to other tropical weathering profiles and is indicative of differential rates of mineral weathering (anorthite > albite ≈ hypersthene > orthoclase ? apatite). Alteration profiles across the cm-thick rinds document dissolution of plagioclase and augite and the growth of kaolinite, with subsequent dissolution of kaolinite and precipitation of gibbsite as weathering rinds age. The rate of weathering rind advance is evaluated using a diffusion-limited model which predicts a parabolic rate law for weathering rind thickness, r_r, as a function of time, t(r_r =), and an interface-limited model which predicts a linear rate law for weathering rind thickness as a function of time (r_r = k_appt). In these rate laws, κ is a diffusion parameter and k_app is an apparent rate constant. The rate of advance is best fit by the interface model.Terrace exposures are confined to the lower reaches of streams draining the Pacific slope near the coast where the stream gradient is less than ∼3 m/km, and terrace deposition is influenced by eustatic sea level fluctuations. Geomorphological evidence is consistent with terrace deposition coincident with sea level maxima when the stream gradient would be lowest. Assigning the most weathered regionally extensive terrace Qt 1 (mean rind thickness 6.9 ± 0. 6cm) to oxygen isotope stage (OIS) 7 (ca. 240 ka), and assuming that at time = 0 rind thickness = 0, it is inferred that terrace Qt 2 (r_r = 2.9 ± 0.1 cm) is coincident with stage 5e (ca. 125 ka) and that Qt 3 (r_r = 0.9 ± 0.1 cm) is consistent with OIS 3 (ca. 37 ka). These assignments yield a value of k_app of 8.6 × 10⁻¹³ cm s⁻¹ (R² = 0.99). Only this value satisfies both the existing age controls and yields ages coincident with sea level maxima. Using this value, elemental weathering release fluxes across a weathering rind from Qt 2 range from 6.0 × 10⁻⁹ mol Si m⁻² s⁻¹ to 2.5 × 10⁻¹¹ mol K m⁻² s⁻¹. The rate of rind advance for the Costa Rican terraces is 2.8 × 10⁻⁷ m yr⁻¹. Basalt rind formation rates in lower temperature settings described in the literature are also consistent with interface-controlled weathering with an apparent activation energy of about 50 kJ mol⁻¹. Rates of rind formation in Costa Rica are an order of magnitude slower than reported for global averages of soil formation rates.  相似文献   

Tectonics, climate, and landscape evolution - Edited by Sean D Willett, Niels Hovius, Mark T Brandon and Donald M Fisher     

Katherine Dobson 《Area》2007,39(3):412-412

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GIS-Based Slope Stability Analysis,Chuquicamata Open Pit Copper Mine,Chile   总被引：1，自引：1，他引：1  

Eric P. Nelson  Katherine A. Connors  Claudio Suárez S. 《Natural Resources Research》2007,16(2):171-190

The risk of slope failure in the Chuquicamata open-pit mine was analyzed using Geographic Information System (GIS) software and modeling techniques. Models incorporated various component layers at a relatively large map scale (1:5000): alteration, geotechnical unit, proximity to major faults (VIF), GSI (geological strength index), slope (from digital elevation model), proximity to watertable (difference grid between topography and modeled watertable), and composite structural density grid (VIF, smaller faults, and fracture frequency); not all layers were used in all models. Three modeling techniques were used: fuzzy logic, in which parameters in each component layer were ranked by mine geotechnical experts according to their influence in promoting slope failure, and two data-driven techniques, weights-of-evidence and logistic regression, in which statistical correlation of training points (known failures) with parameters were used to derive a relative probability of failure. Because most slope failures are controlled by structure, VIF and smaller faults were divided by orientation into subsets with dip direction parallel, opposite, and normal to slope aspect; these orientations promote circular and planar, toppling, and wedge-type failures, respectively. Density grids of these subsets show high-risk areas for individual failure types. The models demonstrate sensitivity of the analysis to (1) selection of component layers, (2) selection of training points, (3) classification and ranking of categorical parameters, and (4) data problems in certain layers. Predicted high-risk zones in the final models show a high degree of correspondence with recent, post-model failures. Such models can be used to anticipate future pit design concerns. The results presented here illustrate how vast amounts of data, in multiple geo-referenced layers, can be analyzed and modeled using GIS techniques for predictive studies at relatively large map scales. Such modeling techniques could provide a powerful tool for predictive modeling in a vast array of large-map-scale applications requiring similar data integration and evaluation.  相似文献   

Field validation of antioxidant enzyme biomarkers in mussels (Perna viridis) and clams (Ruditapes philippinarum) transplanted in Hong Kong coastal waters   总被引：1，自引：1，他引：1  

Sharon B. De Luca-Abbott  Bruce J. Richardson  Katherine E. McClellan  Gene J. Zheng  Michael Martin  Paul K.S. Lam 《Marine pollution bulletin》2005,51(8-12):694

Green-lipped mussels, Perna viridis, and Manila clams, Ruditapes philippinarum were sourced from “clean” sites in the Hong Kong region, depurated in a laboratory using uncontaminated filtered seawater for 8 days, and transplanted to a suspected gradient of chemically polluted sites in Hong Kong. After 14- and 28-days of field exposure, several antioxidant parameters including glutathione S transferase (GST), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) were quantified in gill and hepatopancreas tissues. Whole body tissue concentrations of polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were determined in pooled site samples. Chemical analyses indicated that: (a) clams had higher levels of PAHs, PHCs, DDTs and PCBs, whereas mussels had higher hexachlorocyclohexane (HCHs) and there was no difference between species for dieldrin and remaining OCs; (b) Kat O should not be continued as a “clean” reference site for Hong Kong, because of the levels of contaminants measured and (c) PAH concentrations in the current survey were similar to those previously measured. Toxicological conclusions were: (a) antioxidant responses were different between species; (b) CAT and GST have highest utility in clams for field use in Hong Kong, whereas CAT in both gill and hepatopancreas tissue showed most potential in mussels; (c) significant induction of antioxidant responses over day 0 (excluding GPx in both tissues, and GST in mussel hepatic tissue); (d) groups of contaminants do not consistently induce antioxidant responses and (e) organochlorines and PCBs correlated significantly with CAT and GST in clam hepatopancreas and with CAT in mussel gill and hepatic tissue. Multivariate statistical techniques indicated little relationship between the site patterns for antioxidant responses and the contaminant gradients identified in body burden analysis.  相似文献