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51.
William Pritchard 《Area》1999,31(1):9-17
Summary Internet websites provide a new are na in which companies can create images and representations with attendant geographical narratives. A case study of the websites of the 20 largest US-headquartered food, beverage and food service companies reveals an extensive use of geographical narratives that play on the particular spatial dimensions of the internet. The websites of many of these companies attempt to project and situate corporate activities within a stylized representation of the local and the global, thus providing a 'space' for corporate discourse within cyberspace. Insights gained from this case study highlight the importance of geography and geographical metaphors within the discursive lives of companies. The paper concludes that corporate websites portray idealized identities within idealized geographies. 相似文献
52.
The Fenlands of East Anglia, England, represent a subtle landscape, where topographic highs rarely exceed 30 m above sea level. However, the fens represent an almost full sequence of Quaternary deposits which, together with islands of Cretaceous and Jurassic outcrops, make the area of geological importance. This feature discusses the advantages of using 3D visualization coupled with high‐resolution topographical data, over traditional 2D techniques, when undertaking an analysis of the landscape. Conclusions suggest that the use of 3D visualization will result in a higher level of engagement, particularly when communicating geological information to a wider public. 相似文献
53.
How does the ownership of land affect household livelihood pathways under conditions of deagrarianization? ‘Hanging in’, ‘stepping up’ and ‘stepping out’ in two north Indian villages
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In rural parts of the global South, livelihoods are diversifying away from agriculture. Nevertheless, agriculture typically still remains the backbone of rural life and is usually considered the prime source of economic security, social prestige and self‐identity. The task of narrating these somewhat contradictory processes in a conceptually coherent fashion has proven a major challenge for research. This paper responds to this problem by deploying an adapted version of Andrew Dorward's schema of households ‘hanging in, stepping up or stepping out’ of their landed interests. Dorward's middle‐ground theory provides an appropriate analytical vehicle for capturing the vagaries and situated complexities of the land‐livelihoods nexus. However the theory fails to fully appreciate the extent to which household livelihood decision making rests on complex entanglements that leverage land‐based and nonfarm activities against one another. We demonstrate the critical importance of these processes through the results of in‐depth interviews with 32 households in two north Indian villages. These interviews lead us to propose that land factors in livelihood aspirations in three fundamental ways: an arena for interpenetrated agrarian and nonagrarian livelihood streams; a base for social reproduction; and a bulwark of food (and by extension, livelihood) security through own‐production capabilities. 相似文献
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David J. Garbary Roberta D’Archino Brendan Flack Christopher D. Hepburn Wendy A. Nelson Daniel Pritchard 《新西兰海洋与淡水研究杂志》2020,54(2):167-176
ABSTRACT The tetrasporophytic ‘Trailliella’ stage of the red algal genus Bonnemaisonia is reported for the first time from the Southern Hemisphere. Here we describe a bloom of the tetrasporophyte of B. hamifera from the mouth of the Waikouaiti River, Karitāne, South Island, where it occurred as thousands of free-floating tufts up to 1?cm wide in shallow water, accumulated in windrows on sand banks and beaches, and in the water column at depths of 10–12?m on the adjacent open coast. Gametophytic stages have not yet been found in New Zealand. The material collected to date is strictly vegetative, and reproduction occurs via fragmentation. The identity of the New Zealand samples as B. hamifera was confirmed by both morphology and rbcL sequencing. The abundance and floating dispersal of B. hamifera suggests that it is invasive and will become widely distributed in New Zealand. 相似文献
57.
R. S. W. Braithwaite A. R. Kampf R. G. Pritchard R. P. H. Lamb 《Mineralogy and Petrology》1993,47(2-4):255-261
Summary Orthorhombic barium thiosulfate monohydrate, triclinic barium thiosulfate fluoride, triclinic barium sulfite and monoclinic hydrated barium aluminium trisulfide hydroxide have been isolated and identified as natural weathering products in old smelting mill slags. None of them have been found in nature before, but two of them are known as laboratory products. They represent a stepwise sequence in sulfur oxidation numbers and are potential intermediates in the familiar but little-understood oxidation of sulfides to sulfates and thus throw light on the mechanism of the natural oxidation of sulfide ores. The nature of these phases and co-existing species suggests formation between about Eh -0.45 v at pH 11 and Eh -0.6 v at pH 13.[
Das Vorkommen von Thiosulphaten und anderen unstabilen Schwefelverbindungen als natürliche Venwitterungsprodukte alter Schmelz-Schlacken
Zusammenfassung Orthorhombisches Barium—Monohydrat, triklines Barium-ThiosulfattFluorid, triklines Barium-Sulfit und monoklines, hydriertes Barium-Aluminium-Trisulfid-Hydroxyd sind isoliert und als natürliche Verwitterungsprodukte in alten Schmelzschlacken identifiziert worden. Keine dieser Verbindungen sind bisher in der Natur nachgewiesen worden, jedoch sind zwei davon als Kunstprodukte bekannt. Sie stellen eine schrittweise Abfolge von Schwefeloxydationszahlen dar und sind potentielle Zwischenglieder in der bekannten, aber wenig verstandenen Oxydation von Sulfiden zu Sulfaten. In diesem Sinne werfen sie auch Licht auf den Mechanismus der natürli-chen Oxydation von Sulfiderzen. Die Art dieser und koexistierender Verbindungen legt eine Bildung zwischen Eh -0.45 v bei pH 11 und Eh -0.6 v bei pH 13 nahe.相似文献
58.
Platform carbonates of the Upper Triassic Dachstein Limestone in Naszály Hill have been karstified extensively over the past 200 million years. They provide an excellent example of polyphase karstic diagenesis that is probably typical of many subaerially exposed carbonate sequences. Seven karstic phases are recognized in the area, each of which include polyphase karstic events. The first karst phase was associated with the Löfer cycles. Meteoric waters caused dissolution; enlarged fractures and cavities, were filled by marine and/or vadose silts and cement. The second karst phase was caused by local tectonic movements. Bedding-plane-controlled phreatic caves were formed, and filled by silts. The third karst phase lasted from the end of the Triassic to the Eocene. This was a regional, multiphase karstic event related to younger composite unconformities. Bauxitic fill is the most characteristic product of this phase. The karst terrain reached its mature or senile stage with very little porosity. Narrow veins and floating rafts of white calcite marks karst phase 4, which resulted from hydrothermal activity associated with Palaeogene magmatism. The early Rupelian phase of Alpine uplift caused large-scale rejuvenation of the former karst terrain (karst phase 5). Subsequently Naszály Hill was buried as an area of juvenile karst with significant porosity. A second period of hydrothermal activity in the area (karst phase 6) was induced by Miocene volcanism, which resulted in wide, pale green calcite veins. Finally karst phase 7 was of tectonic origin. Following the most recent, Miocene uplift of the Naszály Hill, the carbonates have again become the site of vadose karst development. 相似文献
59.
The seismic anomaly beneath Iceland extends down to the mantle transition zone and no deeper 总被引:8,自引:0,他引:8
G. R. Foulger M. J. Pritchard B. R. Julian J. R. Evans R. M. Allen G. Nolet W. J. Morgan B. H. Bergsson P. Erlendsson S. Jakobsdóttir S. Ragnarsson R. Stefansson K. Vogfjörd 《Geophysical Journal International》2000,142(3):F1-F5
A 3-D teleseismic tomography image of the upper mantle beneath Iceland of unprecedented resolution reveals a subvertical low wave speed anomaly that is cylindrical in the upper 250 km but tabular below this. Such a morphological transition is expected towards the bottom of a buoyant upwelling. Our observations thus suggest that magmatism at the Iceland hotspot is fed by flow rising from the mantle transition zone. This result contributes to the ongoing debate about whether the upper and lower mantles convect separately or as one. The image also suggests that material flows outwards from Iceland along the Reykjanes Ridge in the upper 200 km, but is blocked in the upper 150 km beneath the Tjornes Fracture Zone. This provides direct observational support for the theory that fracture zones dam lateral flow along ridges. 相似文献
60.