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131.
Cheryl McEwan  David Bek 《Geoforum》2006,37(6):1021-1034
Despite being a poorly defined and vague concept, empowerment is currently of political and theoretical significance and nowhere more so than in South Africa, where it seen as central to post-apartheid transformation. This paper explores the ways in which empowerment has been understood, defined and deployed by post-apartheid governments in the context of a gradual shift from nation-building to neo-liberal governance. It examines the impact of legislation and government policy through a critical examination of empowerment initiatives in the wine industry. Drawing on research conducted in the Western Cape in 2004, the paper analyses how empowerment is interpreted and appropriated both within legislation and specifically within the wine industry. It explores what the wine industry reveals about the disempowering work of neo-liberalism, even as it is couched in the discourses of empowerment. Findings suggest that equating empowerment with economic empowerment threatens to reinforce structures of domination, rather than transforming them, while leaving power relations largely untouched. The case study reveals that until more radical understandings of power and empowerment are acknowledged and incorporated into government policies the failure to address broader issues of social and economic transformation will persist and policies aimed at the empowerment of marginalised individuals and communities will continue to have apparently pre-determined and depoliticised outcomes.  相似文献   
132.
Intrinsic bioremediation of a petroleum-impacted wetland   总被引:4,自引:0,他引:4  
Following the 1994 San Jacinto River flood and oil spill in southeast Texas, a petroleum-contaminated wetland was reserved for a long-term research program to evaluate bioremediation as a viable spill response tool. The first phase of this program, presented in this paper, evaluated the intrinsic biodegradation of petroleum in the contaminated wetland. Sediment samples from six test plots were collected 11 times over an 11-month period to assess the temporal and spatial petroleum concentrations. Petroleum concentrations were evaluated using gas chromatography-mass spectrometer analyses of specific target compounds normalized to the conservative biological marker, C(30)17alpha,21beta(H)-hopane. The analyses of specific target compounds were able to characterize that significant petroleum biodegradation had occurred at the site over the one-year period. Total resolved saturate and total resolved aromatic hydrocarbon data indicated the petroleum was degraded more than 95%. In addition, first-order biodegradation rate constants were calculated for the hopane-normalized target compounds and supported expected biodegradation patterns. The rapid degradation rates of the petroleum hydrocarbons are attributed to conditions favorable to biodegradation. Elevated nutrient levels from the flood deposition and the unconsolidated nature of the freshly deposited sediment possibly provided a nutrient rich, oxic environment. Additionally, it is suggested that an active and capable microbial community was present due to prior exposure to petroleum. These factors provided an environment conducive for the rapid bioremediation of the petroleum in the contaminated wetland.  相似文献   
133.
Bate  Bate  Cao  Junnan  Zhang  Chi  Hao  Na 《Acta Geotechnica》2021,16(3):841-857

Heterogeneity in either chemically or microbiologically induced carbonate-based ground improvement methods is a major obstacle in engineering application. Spectral induced polarization (SIP), an innovative and nondestructive method, which has demonstrated promise in monitoring microbial activity, was used in this study to monitor enzyme induced carbonate precipitation (EICP). The complex conductivities, together with the shear wave velocities (Vs), of an EICP modified sand were monitored using a self-developed spectral induced polarization–bender element column. The mean precipitate size was calculated by relaxation time (τ) and the Schwarz equation. The precipitate contents were calculated by cumulative gamma distribution function on the global polarization magnitude (mn) with R2?=?0.989. The stiffness of the enhanced geomaterial, in terms of Vs, correlates to mn with a cumulative lognormal distribution function with R2?=?0.967. Contact cementation was postulated as the dominant association pattern. The possible mechanism for this may be the formation of eddies and the nucleation of CaCO3 crystals during precipitation. The results suggest that SIP can be used as an effective nondestructive monitoring tool to assess the stiffness of geomaterials.

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134.
Bate  Bate  Nie  Shaokai  Chen  Zejian  Zhang  Fengshou  Chen  Yunmin 《Acta Geotechnica》2021,16(6):1949-1960
Acta Geotechnica - The soil–water characteristic curve (SWCC) of granular materials is crucial for many emerging engineering applications, such as permeable pavement and methane hydrate...  相似文献   
135.
Shallow groundwater (>30 mbgl) is an essential source of drinking water to rural communities in the Ndop plain, northwest Cameroon. As a contribution to water management, the effect of seasonal variation on the groundwater chemistry, hydrochemical controls, drinking quality and recharge were investigated during the peaks of the dry (January) and rainy (September) seasons. Field measurements of physical parameters were preceded by sampling 58 groundwater samples during both seasons for major ions and stable isotope analyses. The groundwater, which was barely acidic (mean pH of 6) and less mineralised (TDS < 272 mg/l), showed no significant seasonal variation in temperature, pH and TDS during the two seasons. The order of cation abundance (meq/l) was Na+ > Ca2+ > Mg2+ > K+ and Na+ > Mg2+ > Ca2+ > K+ in the dry and rainy seasons, respectively, but that of anions ( \( {\text{HCO}}_{3}^{ - } \)  >  \( {\text{NO}}_{3}^{ - } \)  > Cl? >  \( {\text{SO}}_{4}^{2 - } \)  > F?) was similar in both seasons. This suggests a negligible effect of seasonal variations on groundwater chemistry. The groundwater, which was CaMgHCO3 and NaHCO3, is chemically evolved rainfall (CaMgSO4Cl) in the area. Silicate mineral dissolution and cation-exchange were the main controls on groundwater chemistry while there was little anthropogenic influence. The major ions and TDS concentrations classified the water as suitable for human consumption as per WHO guidelines. The narrow cluster of δ18O and δD of same groundwater from both seasons between the δ18O and δD values of May–June precipitation along the Ndop Meteoric Water Line indicates meteoric origin, rapid recharge (after precipitation) and timing of recharge between May and June rainfall. Diffuse groundwater recharge mainly occurs at low altitudes (<1,400 m asl) within the plain. Besides major ions and TDS, the similar δ18O and δD of groundwater from both seasons indicate a consistent groundwater recharge and flow pattern throughout the year and resilience to present day short-term seasonal climatic variations. However, controlled groundwater abstraction is recommended given the increasing demand.  相似文献   
136.
West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Niños, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.  相似文献   
137.
Diaz  John  Carnevale  Shannon  Millett  Cheryl  Abd-Elrahman  Amr  Britt  Katie 《Natural Hazards》2020,103(2):1905-1916
Natural Hazards - Natural ecosystems are characterized as dynamic systems that evolve through natural patterns of disturbance. Land managers can work within this system of natural disturbance by...  相似文献   
138.
Kang  X.  Cao  J.  Bate  B. 《Acta Geotechnica》2020,15(12):3605-3611

Shear wave velocity (Vs) anisotropy of kaolinite mixed with sodium chloride (NaCl) and organic polymer (polyethylene oxide, xanthan gum, and chitosan) solutions was investigated using a custom-made floating wall consolidometer-type bender element testing system. The addition of salt and polymers influenced the microfabric anisoopy of platy kaolinite particles, thus resulted in the increment or decrement in the Vs anisotropy. The Vs of kaolinite in all three orthogonal directions increased as the NaCl concentration increased; however, the Vs anisotropy decreased. PEO and chitosan increased the Vs of kaolinite, while xanthan gum exhibited counter-effects. Vs anisotropy (Vs?hh/Vs?vh and Vs?hv/Vs?vh) of polymer amended kaolinite was found to decrease. In addition, both salt- and polymer-modified kaolinite did not show Vs cross-anisotropy.

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