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621.
David Newman 《GeoJournal》2001,53(3):235-246
Territory remains a central component of national identity in the contemporary political discourse between Israelis and Palestinians, both populations opposing power sharing within the same space, for fear of the other's domination. The contemporary political discourse relates to conflict management and the desire for separate spaces within which national identities are strengthened through territorial/national homogeneity. The Zionist national ideology of most Jewish citizens of Israel has strong territorial roots; hence they reject the post-Zionist post-nationalist ideology, regardless of whether they accept the possibility of change in Israel's territorial configuration or of a diminishment in the importance of the territorial dimension of national struggle. The rights of residency and citizenship even of second and third generation Jewish citizens remain linked with the territorial configurations of a State that will continue to be called Israel and have a national anthem expressing the aspirations of a single, exclusive, national group. But within territorial readjustment, issues of configuration may become less relevant and in it is this sense that post-Zionism focuses on a discourse of territorial pragmatism, rather than the disappearance of territory from the nationality-citizenship debate altogether. It is part of a process of re-territorialization and spatial reconfiguration of political and national identities, not a reversal of territorialization, if only because there is no such thing as a post-territorial notion of the organization of political power. The boundaries of national identity become more permeable, more inclusive, but they do not disappear altogether.  相似文献   
622.
Industrial archaeology has developed as an important aspect of conservation during the second half of the twentieth century in the Western world and there have been great opportunities in transition countries since 1989 on account of economic restructuring and the importance given to 'niche' tourism. While the core interest lies with machines and industrial buildings, attention is also given to transport systems and the social context, with respect to relations between owners, managers and workers. Moreover, the desirability of maintaining old industrial installations within their traditional landscape settings enables industrial archaeology to make a contribution to sustainable development. This paper considers the prospects for Romania, with particular reference to the Reşiţa area of the Banat Carpathians. The mineral resources of this region gave rise to a metallurgical industry which was established under Habsburg administration in the eighteenth century and continues today. In addition to the principal factories in Anina and Reşiţa, the mining installations, transport systems and power stations contribute to a diverse industrial region in a distinctive physical and cultural setting. The development of the complex is summarised and the opportunities for conservation are evaluated. The tourist infrastructure of the area is also examined with regard to the range of accommodation available. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
623.
Silicified deposits, such as sinters, occur in several modern geothermal environments, but the mechanisms of silicification (and crucially the role of microorganisms in their construction) are still largely unresolved. Detailed examination of siliceous sinter, in particular sections of microstromatolites growing at the Krisuvik hot spring, Iceland, reveals that biomineralization contributes a major component to the overall structure, with approximately half the sinter thickness attributed to silicified microorganisms. Almost all microorganisms observed under the scanning electron microscope (SEM) are mineralized, with epicellular silica ranging in thickness from < 5 μm coatings on individual cells, to regions where entire colonies are cemented together in an amorphous silica matrix tens of micrometres thick. Within the overall profile, there appears to be two very distinct types of laminae that alternate repeatedly throughout the microstromatolite: ‘microbial’ layers are predominantly consisting of filamentous, intact, vertically aligned, biomineralized cyanobacteria, identified as Calothrix and Fischerella sp.; and weakly laminated silica layers which appear to be devoid of any microbial component. The microbial layers commonly have a sharply defined base, overlying the weakly laminated silica, and a gradational upper surface merging into the weakly laminated silica. These cyclic laminations are probably explained by variations in microbial activity. Active growth during spring/summer allows the microorganisms to keep pace with silicification, with the cell surfaces facilitating silicification, while during their natural slow growth phase in the dark autumn/winter months silicification exceeds the bacteria’s ability to compensate (i.e. grow upwards). At this stage, the microbial colony is probably not essential to microstromatolite formation, with silicification presumably occurring abiogenically. When conditions once again become favourable for growth, recolonization of the solid silica surface by free‐living bacteria occurs: cell motility is not responsible for the laminations. We have also observed that microbial populations within the microstromatolite, some several mm in depth, appear viable, i.e. they still have their pigmentation, the trichomes are not collapsed, cell walls are unbroken, cytoplasm is still present and they proved culturable. This suggests that the bulk of silicification occurred rapidly, probably while the cells were still alive. Surprisingly, however, measurements of light transmittance through sections of the microstromatolite revealed that photosynthetically active light (PAL) only transmitted through the uppermost 2 mm. Therefore the ‘deeper’ microbial populations must have either: (i) altered their metabolic pathways; (ii) become metabolically inactive; or (iii) the deeper populations may be dominated by different microbial assemblages from that of the surface. From these collective observations, it now seems unequivocal that microstromatolite formation is intimately linked to microbial activity and that the sinter fabric results from a combination of biomineralization, cell growth and recolonization. Furthermore, the similarities in morphology and microbial component to some Precambrian stromatolites, preserved in primary chert, suggests that we may be witnessing contemporaneous biomineralization processes and growth patterns analogous to those of the early Earth.  相似文献   
624.
Current advances in computer hardware, information technology and data collection techniques have produced very large data sets in a wide variety of scientific and engineering disciplines. We must harness this opportunity to visualize and extract useful information from geophysical and geological data. We have taken the task of data mining by implementing a map-like approach over a web server for interrogating the data, using a client-server paradigm. The spatial-data is mapped onto a two-dimensional grid from which the user (client) can quiz the data with the map-interface as a user extension. The data is stored on the server, while the computational gateway separating the client and the server can be the front-end of an electronic publication, electronic classroom, a survey, or an e-business. We have used a combination of Java, Java3D, and Perl for processing the data and communicating between the client and the server. The user can interrogate the geospatial data over any particular region with arbitrary dimensions and then receive back relevant statistical analysis, such as the histogram plots and local statistics. We have applied this method for the following data sets: (1.) distribution of prime numbers (2.) two-dimensional mantle convection (3.) three-dimensional mantle convection (4.) high-resolution satellite reflectance data over multiple wavelengths (5.) molecular dynamics describing the flow of blood in narrow vessels. Using the map-interface, one can actually interrogate this data over the Internet.  相似文献   
625.
Several strike–slip faults at Crackington Haven, UK show evidence of right-lateral movement with tip cracks and dilatational jogs, which have been reactivated by left-lateral strike–slip movement. Evidence for reactivation includes two slickenside striae on a single fault surface, two groups of tip cracks with different orientations and very low displacement gradients or negative (left-lateral) displacements at fault tips.

Evidence for the relative age of the two strike–slip movements is (1) the first formed tip cracks associated with right-lateral slip are deformed, whereas the tip cracks formed during left-lateral slip show no deformation; (2) some of the tip cracks associated with right-lateral movement show left-lateral reactivation; and (3) left-lateral displacement is commonly recorded at the tips of dominantly right-lateral faults.

The orientation of the tip cracks to the main fault is 30–70° clockwise for right-lateral slip, and 20–40° counter-clockwise for left-lateral slip. The structure formed by this process of strike–slip reactivation is termed a “tree structure” because it is similar to a tree with branches. The angular difference between these two groups of tip cracks could be interpreted as due to different stress distribution (e.g., transtensional/transpressional, near-field or far-field stress), different fracture modes or fractures utilizing pre-existing planes of weakness.

Most of the dx profiles have similar patterns, which show low or negative displacement at the segment fault tips. Although the dx profiles are complicated by fault segments and reactivation, they provide clear evidence for reactivation. Profiles that experienced two opposite slip movements show various shapes depending on the amount of displacement and the slip sequence. For a larger slip followed by a smaller slip with opposite sense, the profile would be expected to record very low or reverse displacement at fault tips due to late-stage tip propagation. Whereas for a smaller slip followed by larger slip with opposite sense, the dx profile would be flatter with no reverse displacement at the tips. Reactivation also decreases the ratio of dmax/L since for an original right-lateral fault, left lateral reactivation will reduce the net displacement (dmax) along a fault and increase the fault length (L).

Finally we compare Crackington Haven faults with these in the Atacama system of northern Chile. The Salar Grande Fault (SGF) formed as a left-lateral fault with large displacement in its central region. Later right-lateral reactivation is preserved at the fault tips and at the smaller sub-parallel Cerro Chuculay Fault. These faults resemble those seen at Crackington Haven.  相似文献   

626.
Reproductive pentoxylalean material from the Albian Triton Point Formation, Fossil Bluff Group of Alexander Island, Antarctica is the youngest record of this group globally. Leaves are referred to Taeniopteris daintreei McCoy, ovulate reproductive organs to Carnoconites cranwelli Harris, and stem material to Pentoxylon sp. Occurring in leaf litter layers on palaeosol surfaces the sedimentology suggests that pentoxylalean plants grew upon areas of the floodplain distal to the river channel, where they covered the forest floor in a similar habit to modern brambles. The forest floor was shared with Equisetales and liverworts, an abundance of ferns [Cladophlebis Brongniart, Gleichenites Goeppert, Phyllopteroides Medwell, Sphenopteris (Brongniart) Sternberg], as well as angiosperms. Bennettitales, Ginkgoites Seward and Nilssonia Brongniart were rare within these communities, as were coniferous trees.  相似文献   
627.
628.
A current pursuit of the geodetic community is the optimal integration of differential GPS (DGPS) and inertial navigation system (INS) data streams for precise and efficient position and gravity vector surveying. Therein a complete INS and multiple-antenna GPS receiver payload, mounted on a moving platform, is used in conjunction with a network of ground-fixed single antenna GPS receivers. This paper presents a complete, GPS-based, external updating measurement model for the applicable Kalman filter. The model utilizes four external observation types for every GPS satellite in-view: DGPS range differences, single phase differences, and single phase-rate differences; as well as the mobile, multipleantenna GPS receiver's measurement of theerrors in the INS's estimate of the phase difference between any two vehicle-borne GPS antennae. Although not widely conveyed in the geodetic world, the inertial navigation community has long known that traditional Kalman filter covariance propagation recurrences are inherently unstable when such highly accurate external updates are repeatedly applied (every 1 second) over long time durations. A hybrid square root covariance/U — D covariance factorization approach is a numerically stable alternative and is reviewed herein. The hybrid makeup of the algorithm is necessitated by the correlated nature of the fourth type of GPS external measurement listed above (each vehicle-borne GPS antenna formstwo baselines). Such measurement correlations require a functional transformation of the overall external updating model to permit the multiple updates (simultaneously available at each updating epoch) to be sequentially (and efficiently) processed. An appropriate transformation is given. Stable covariance propagation relationships are presented and the transformed Kalman gain is also furnished and its use in the determination of the externally updated error states is discussed. Specific DGPS/INS instabilities produced by the traditional recurrences are displayed. The stable alternative method requires about 25% more CPU time than the traditional Kalman recurrences. With the ever-increasing computational speeds of microprocessors, this added CPU time is of no real concern.  相似文献   
629.
[Cu2+] and Cu complexation parameters in some selected freshwater systems in Switzerland were determined by the technique of ligand-exchange and DPCSV. Results from the water columns of some eutrophic and oligotrophic lakes are presented and compared to small acid lakes. Cu is strongly complexed by organic ligands which with very high stability constants at low concentrations are probably biologically produced, as indicated by the seasonal variations in the eutrophic lakes and by the relationship between Cu complexation and algal activity in the eutrophic (pCu=15–16), oligotrophic (pCu=13–14) and acidic (pCu=9–10) lakes. The extent of Cu complexation in river waters was generally lower than in the eutrophic lakes, at similar DOC levels. No obvious correlation between Cu complexation and DOC was observed, indicating that Cu complexing ligands are specific organic compounds.  相似文献   
630.
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