Constructing economic geographies from corporate interviews: insights from a cross-country comparison of retailer–supplier relationships     

Alex Hughes 《Geoforum》1999,30(4):469

In the light of the significant role played by corporate interviews in the construction of contemporary economic geographies, this paper suggests that the practices of corporate interviewing in the research process demand critical reflection. These practices are reflected upon in the context of a comparative study of retailer–manufacturer power relations in the UK and USA. In particular, attention is paid to the ways in which corporate interviews actively construct knowledge of contrasting own-brand supply relationships in these national economies. To do this, the paper addresses the following issues: (i) the embeddedness of corporate interviews in a transforming economic geography; (ii) the processes of identifying, and gaining access to, own-brand supply networks in the UK and USA; (iii) the use of materials resulting from corporate interviews to produce nuanced understandings of own-brand supply relationships; (iv) the adoption of an appropriate textual strategy for writing such interview-based material into economic geography.  相似文献   

Domicile and Diaspora: Anglo-Indian Women and the Spatial Politics of Home - by Alison Blunt     

Alex  Barley 《The Geographical journal》2006,172(3):265-266

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Elemental and mineralogical changes in soils due to bioturbation along an earthworm invasion chronosequence in Northern Minnesota   总被引：1，自引：0，他引：1  

Kathryn Resner  Kyungsoo Yoo  Cindy Hale  Anthony Aufdenkampe  Alex Blum  Stephen Sebestyen 《Applied Geochemistry》2011

Minnesota forested soils have evolved without the presence of earthworms since the last glacial retreat. When exotic earthworms arrive, enhanced soil bioturbation often results in dramatic morphological and chemical changes in soils with negative implications for the forests’ sustainability. However, the impacts of earthworm invasion on geochemical processes in soils are not well understood. This study attempts to quantify the role of earthworm invasion in mineral chemical weathering and nutrient dynamics along an earthworm invasion chronosequence in a sugar maple forest in Northern Minnesota. Depth and rates of soil mixing can be tracked with atmospherically derived short lived radioisotopes ²¹⁰Pb and ¹³⁷Cs. Their radioactivities increase in the lower A horizon at the expense of the peak activities near the soil surface, which indicate that soil mixing rate and its depth reach have been enhanced by earthworms. Enhanced soil mixing by earthworms is consistent with the ways that the vertical profiles of elemental and mineralogical compositions were affected by earthworm invasion. Biologically cycled Ca and P have peak concentrations near the soil surface prior to earthworm invasion. However, these peak abundances significantly declined in the earthworm invaded soils presumably due to enhanced soil mixing. It is clear that enhanced soil mixing due to earthworms also profoundly altered the vertical distribution of most mineral species within A horizons. Though the mechanisms are not clear yet, earthworm invasion appears to have contributed to net losses of clay mineral species and opal from the A horizons. As much as earthworms vertically relocated minerals and elements, they also intensify the contacts between organic matter and cations as shown in the increased amount of Ca and Fe in organically complexed and in exchangeable pools. With future studies on soil mixing rates and elemental leaching, this study will quantitatively and mechanically address the role of earthworms in geochemical evolution of soils and forests’ nutrient dynamics.  相似文献   

New insight on the genus Nolaniceras Casey, 1961 (Ammonoidea,Cretaceous) and its consequences on the biostratigraphy of the Aptian Stage     

Luc G. Bulot  Jean-Louis Latil  Alex Hairabian  Arnaud Fournillon 《Proceedings of the Geologists' Association. Geologists' Association》2014

Nolaniceras nolani ( Seunes, 1887) has been widely quoted in the Upper Aptian literature over the years. Re-examination of the holotype of the species shows that it has always been misidentified and that this taxon is represented by a single specimen, the holotype, of uncertain age. As a consequence, its use as an index species for the Upper Aptian should be reconsidered and abandoned.  相似文献   

Exploring weathering and regolith transport controls on Critical Zone development with models and natural experiments     

Suzanne P. Anderson  Robert S. Anderson  Eve-Lyn S. Hinckley  Patrick Kelly  Alex Blum 《Applied Geochemistry》2011

The architecture of the Critical Zone, including mobile regolith thickness and depth to the weathering front, is first order controlled by advance of a weathering front at depth and transport of sediment at the surface. Differences in conditions imposed by slope aspect in the Gordon Gulch catchment of the Boulder Creek Critical Zone Observatory present a natural experiment to explore these interactions. The weathering front is deeper and saprolite more decayed on north-facing than on south-facing slopes. Simple numerical models of weathering front advance, mobile regolith production, and regolith transport are used to test how weathering and erosion rates interact in the evolution of weathered profiles. As the processes which attempt are being made to mimic are directly tied to climate variables such as mean annual temperature, the role of Quaternary climate variation in governing the evolution of Critical Zone architecture can be explored with greater confidence.  相似文献   

Three-Dimensional Modeling of the Casing Effect in Onshore Controlled-Source Electromagnetic Surveys     

Vladimir Puzyrev  Eloi Vilamajo  Pilar Queralt  Juanjo Ledo  Alex Marcuello 《Surveys in Geophysics》2017,38(2):527-545

The presence of steel-cased wells and other infrastructure causes a significant change in the electromagnetic fields that has to be taken into consideration in modeling and interpretation of field data. A realistic and accurate simulation requires the borehole casing to be incorporated into the modeling scheme, which is numerically challenging. Due to the huge conductivity contrast between the casing and surrounding media, a spatial discretization that provides accurate results at different spatial scales ranging from millimeters to hundreds of meters is required. In this paper, we present a full 3D frequency-domain electromagnetic modeling based on a parallel finite-difference algorithm considering the casing effect and investigate its applicability on the borehole-to-surface configuration of the Hontomín CO₂ storage site. To guarantee a robust solution of linear systems with highly ill-conditioned matrices caused by huge conductivity contrasts and multiple spatial scales in the model, we employ direct sparse solvers. Different scenarios are simulated in order to study the influence of the source position, conductivity model, and the effect of the steel casing on the measured data. Several approximations of the real hollow casing that allow for a large reduction in the number of elements in the resulting meshes are studied. A good agreement between the modeled responses and the real field data demonstrates the feasibility of simulating casing effects in complex geological areas. The steel casing of the well greatly increases the amplitude of the surface electromagnetic fields and thus improves the signal-to-noise ratio and the sensitivity to deep targets.  相似文献   

    

Alex Jeffrey  Colin McFarlane  Alexander Vasudevan 《Singapore journal of tropical geography》2008,29(3):251-253

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Raman spectroscopy and biomarker analysis reveal multiple carbon inputs to a Precambrian glacial sediment     

Alison Olcott Marshall  Frank A. Corsetti  Alex L. Sessions  Craig P. Marshall 《Organic Geochemistry》2009,40(11):1115-1123

Extractable biomarkers can help elucidate the environment and biota of ancient glaciations, although the method must be applied with care, as glacial sediments have a potential for incorporation of older detrital carbon. In Phanerozoic glacial sediments, the distinct elemental, molecular and isotopic compositions of the terrestrial and marine biomass allow discrimination between primary marine and redeposited terrestrial organic matter. However, as the Proterozoic biosphere was largely microbial and marine, biomarker and isotopic analyses are insufficient for distinguishing primary organic matter from secondary reworked organic matter. Here, we report the combined application of Raman spectroscopy and biomarker analysis to Precambrian glacial sediments, which, together, allows discrimination between mixed pools of organic carbon and provides a promising new approach for rapidly screening Precambrian sediments for immature organic matter amenable to biomarker analysis.  相似文献   

    

Daniel Wallach  Linda O. Mearns  Alex C. Ruane  Reimund P. Rötter  Senthold Asseng 《Climatic change》2016,138(3-4):551-566

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Alex O. Onojeghuo  George A. Blackburn  Qunming Wang  Peter M. Atkinson  Daniel Kindred  Yuxin Miao 《地理信息系统科学与遥感》2018,55(5):659-677

Satellite data holds considerable potential as a source of information on rice crop growth which can be used to inform agronomy. However, given the typical field sizes in many rice-growing countries such as China, data from coarse spatial resolution satellite systems such as the Moderate Resolution Imaging Spectroradiometer (MODIS) are inadequate for resolving crop growth variability at the field scale. Nevertheless, systems such as MODIS do provide images with sufficient frequency to be able to capture the detail of rice crop growth trajectories throughout a growing season. In order to generate high spatial and temporal resolution data suitable for mapping rice crop phenology, this study fused MODIS data with lower frequency, higher spatial resolution Landsat data. An overall workflow was developed which began with image preprocessing, calculation of multi-temporal normalized difference vegetation index (NDVI) images, and spatiotemporal fusion of data from the two sensors. The Spatial and Temporal Adaptive Reflectance Fusion Model was used to effectively downscale the MODIS data to deliver a time-series of 30 m spatial resolution NDVI data at 8-day intervals throughout the rice-growing season. Zonal statistical analysis was used to extract NDVI time-series for individual fields and signal filtering was applied to the time-series to generate rice phenology curves. The downscaled MODIS NDVI products were able to characterize the development of paddy rice at fine spatial and temporal resolutions, across wide spatial extents over multiple growing seasons. These data permitted the extraction of key crop seasonality parameters that quantified inter-annual growth variability for a whole agricultural region and enabled mapping of the variability in crop performance between and within fields. Hence, this approach can provide rice crop growth data that is suitable for informing agronomic policy and practice across a wide range of scales.  相似文献