共查询到20条相似文献，搜索用时 15 毫秒
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Clare Newstead 《Geoforum》2005,36(1):45-58
Recently there has been much ado about the territorial implications of globalization. Geographers have made a significant contribution to these debates, pointing to the tension between forces of deterritorialization and those of re-territorialization. In particular, there is a growing body of work in political and economic geography that draws attention to processes of re-scaling where, at the same time as scales such as the nation-state appear threatened, new scales of economic, political and social regulation emerge. Much of this literature, however, focuses on the ability of already powerful states to re-scale their activities and manage the border crossing abilities of global capital. In this paper I examine the process of supra-national regional integration in the Caribbean as an example of re-scaling and re-territorialization in a post-colonial context. I draw attention to the historic permeability of Caribbean states and argue regionalism in the Caribbean needs to be viewed as part of a longer process of defining economic, political and cultural independence in what, for post-colonial states, has always been an interdependent world economy. This analysis suggests that while new scales can be understood as spatialized attempts to manage changing global economics, they are also ambivalent productions, and as such, sites of resistance as well as domination and regulation. 相似文献
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Smelt (Osmerus mordax) from six rivers along the coast of Massachusetts were examined for the microsporidianGlugea hertwigi and piscine erythrocytic necrosis (PEN), a viral blood disease. Of the 485 smelt sampled, 13.4% were affected byGlugea. Incidence ranged from 18.0% in the Town River to 0% in the Parker River. PEN was observed in all river systems. Incidence ranged from 97% in the Jones to 61% in the Parker River. Individual intensity of infection was low, with the majority of fish having less than 1% of their erythrocytes affected. The highest intensity for an individual specimen was 4.68%. 相似文献
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Robert H. Brewer 《Estuaries and Coasts》1978,1(2):120-122
The distribution of sessile marine invertebrates is often the consequence of the selection of a suitable substrate by motile larvae. Motile planulae larvae ofAurelia aurita (Linnaeus) are exposed to an artificial substrate in the laboratory to determine if they possess the capacity both for specific orientation and for discrimination of surface texture at time of attachment. More than 90% (P<0.001) of the planulae fasten to the underside of objects. As a result, developing scyphistomae hang with the oral surface downward as commonly encountered in the field. The effect of surface texture on planula attachment is equivocal; this may reflect an indifference to surface texture, a limited capacity to locomote across rough substrate, or a mechanism of response sensitive only to large surface irregularities. These results are compared with those obtained for the planulae ofCyanea capillata (Linnaeus). The planular effected orientation of the scyphistoma may be generally true for coastal representatives of the Semaeostomeae, and perhaps for other shallow water Scyphozoa (including the Class Cubozoa). 相似文献
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尹福光 《沉积与特提斯地质》2003,23(4):79-83
康滇地区裂谷作用已得到证实,但形成这种地堑地垒的格局有多种解释,以传统的地质力学分析为主。笔者借以热力学的自由热对流原理来加以论述：攀西巨厚的火山岩体在下覆异常地幔热作用下,发生自由热对流,引起热量散失,使地壳沉降与隆起不均衡,生成地堑地垒的格局。自由对流单元的侧向迁移,使盆地形成非对称性。 相似文献
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Multiple sources for mineralizing fluids in the Charmitan gold(-tungsten) mineralization (Uzbekistan) 总被引：1，自引：0，他引：1
Torsten Graupner Samuel Niedermann Dieter Rhede Ulf Kempe Reimar Seltmann C. Terry Williams Reiner Klemd 《Mineralium Deposita》2010,45(7):667-682
Mineral assemblages present within the Charmitan gold(-tungsten) quartz-vein mineralization have been investigated for their
cathodoluminescence behaviour, chemical composition and noble gas isotope systematics. This inventory of methods allows for
the first time a systematic reconstruction of the paragenetic relationships of quartz, scheelite, sulphides and native gold
within the gold mineralization at Charmitan and provides the basis to utilise noble gas data in the discussion of sources
and evolution of ore-forming fluids. The vein quartz is classified into four generations based on microscopic and cathodoluminescence
investigations. Quartz I shows intense brittle deformation as associated scheelite I. Undeformed scheelite II overgrows scheelite
I and has lower light rare earth element and higher intermediate rare earth element contents as well as higher strontium concentrations.
Scheelite II is associated with the economic gold mineralization and formed during re-crystallisation and re-precipitation
of material which was partly re-mobilised from early scheelite I during infiltration of gold-bearing fluids. Early stage native
gold inclusions are often associated with stage 2 sulphides, scheelite II and bismuth tellurides and contain Ag (3.6–24.4 wt.%),
Hg (≤1.0 wt.%) and Bi (≤0.2 wt.%). Later stage electrum grains occur in association with stage 3 sulphides and sulphosalts
and contain Hg (<0.8 wt.%) and elevated Sb concentrations (up to 3.0 wt.%). Noble gas isotope data (3He/4He: 0.2-0.4 Ra) for hydrothermal ore fluids trapped in the gold-related sulphides and sulphosalts (stage 2 pyrite and arsenopyrite;
stage 3 pyrite, sphalerite, galena and lead sulphosalts) suggest that diverse fluid sources were involved in the formation
of the Charmitan gold deposit. These data are indicative of a small, but significant input of fluids from external, deep-seated
(mantle and possibly lower crust) sources. A decrease in the input of mantle helium and an increasing role of crustal helium
from early to later stages of the mineralization is suggested by the measured 3He/4He and 40Ar*/4He ratios. Sulphides from ore veins in meta-sedimentary rocks contain higher portions of meteoric fluids than those in intrusive
rock types as indicated by their lower 3He/36Ar ratios. The 3He/36Ar ratios in the meta-sedimentary rocks agree well with ratios typical of gold mineralizations in the Tien Shan gold province
completely hosted by meta-sedimentary sequences, indicating intense fluid-wall rock interaction. 相似文献
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Kim Won Sa Department of Geology Chungnam National University Taejon - Korea 《中国地质大学学报(英文版)》2000,11(2)
INTRODUCTIONA new gem- quality serpentine deposit was discovered in1995 in Booyo area,about 2 5 0 km southwest of Seoul,Korea(Fig.1) and is being mined by the Booyo Nokok (meaninggreen jade) Mining Company.After the Booyo material isfashioned into rings,beads,cabochons,pendants and ear-rings,they are traded on the domestic market under the nameof “Booyo precious serpentine”.The green Booyo bowenite(serpentine jade) has gained high reputation in the countryand a much higher value tha… 相似文献
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Matthew G. Hannah 《GeoJournal》2010,75(4):397-406
Ewald’s recent genealogy of constructions of risk in Western societies argues that the 1980s saw an important paradigm shift
to the “precautionary principle”. Critical scholars have taken up this idea as a lens through which to interpret the Bush
administration’s ‘war on terror’. I argue that 11 September 2001 actually brought about qualitative changes to this paradigm.
Bush’s pre-emptive doctrine is driven, and perhaps even more importantly, continually justified to the US population, by what
might be called the “trans-precautionary principle”, a move from “decisionism” to “actionism”, and a new radicalization of
the way fear is produced and managed. Donald Rumsfeld’s famous typology of different articulations of knowledge and ignorance
offers an excellent analytical window onto the connections between ignorance, fear and geopolitical action in this new regime.
In the latter part of the essay, his four modes of knowledge/ignorance are arrayed, for heuristic purposes, in an abstract
spatial grid organized along dimensions of the specificity and possession of knowledge. This allows a ‘mapping’ of some of
the Bush administration’s more controversial strategies in the ‘war on terror’, as a set of different pathways through Rumsfeld
Space. 相似文献
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Imprecise (fuzzy) information in geostatistics 总被引：2，自引：0，他引：2
A methodology based on fuzzy set theory for the utilization of imprecise data in geostatistics is presented. A common problem preventing a broader use of geostatistics has been the insufficient amount of accurate measurement data. In certain cases, additional but uncertain (soft) information is available and can be encoded as subjective probabilities, and then the soft kriging method can be applied (Journel, 1986). In other cases, a fuzzy encoding of soft information may be more realistic and simplify the numerical calculations. Imprecise (fuzzy) spatial information on the possible variogram is integrated into a single variogram which is used in a fuzzy kriging procedure. The overall uncertainty of prediction is represented by the estimation variance and the calculated membership function for each kriged point. The methodology is applied to the permeability prediction of a soil liner for hazardous waste containment. The available number of hard measurement data (20) was not enough for a classical geostatistical analysis. An additional 20 soft data made it possible to prepare kriged contour maps using the fuzzy geostatistical procedure.This paper was presented at MGUS 87 Conference, Redwood City, California, 14 April 1987. 相似文献
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We consider models of a wormhole (i) maintained by an electromagnetic field, taking into account quantum vacuum corrections to the equation of state, (ii) maintained by a combination of the magnetic field and phantom energy, with a spherically symmetrical equation of state, and (iii) with a magnetic field and phantom matter with an anisotropic equation of state. It is shown that the quantum corrections and the density and exoticity of phantom energy or matter can be as small as is desired. For an external observer, the entrance to the tunnel appears to be a magnetic monopole of macroscopic size. The accretion of ordinary matter onto the entrance to the tunnel may result in the formation of a black hole with a radial magnetic field. We consider the possibility that some active galactic nuclei and Galactic objects may be current or former entrances to magnetic wormholes. We consider the possible existence of a broad mass spectrum for wormholes, from several billion solar masses to masses of the order of 2 kg. The Hawking effect (evaporation) does not operate in such objects due to the absence of a horizon, making it possible for them to be retained over cosmological time intervals, even if their masses are smaller than 1015 g. We also discuss a model for a binary system formed by the entrances of tunnels with magnetic fields, which could be sources of nonthermal radiation and γ-ray bursts. 相似文献
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Fe(III) complexed by organic ligands (Fe(III)L) is the primary form of dissolved Fe in marine and coastal environments. Superoxide, typically produced in biological and photochemical processes, is one of the reducing agents that contributes to transformation of Fe(III)L to bioavailable, free dissolved Fe(II) (Fe(II)′). In this work, the kinetics of superoxide-mediated Fe(II)′ formation from Fe(III)L in a simulated coastal water system were investigated and a comprehensive kinetic model was developed using citrate and fulvic acid as exemplar Fe-binding ligands. To simulate a coastal environment in laboratory experiments, Fe(III)L samples with various ligand/Fe ratios were incubated for 5 min to 1 week in seawater medium. At each ratio and incubation time, the rate of superoxide-mediated Fe(II)′ formation was determined in the presence of the strong Fe(II) binding ligand ferrozine by spectrophotometrically measuring the ferrous-ferrozine complex generated at a constant concentration of superoxide. The Fe(II)′ formation rate generally decreased with incubation time, as Fe(III)L gradually dissociated to form less reactive Fe(III) oxyhydroxide. However, when the ligand/Fe ratio was sufficiently high, the dissociation of Fe(III)L (and subsequent Fe precipitation) was suppressed and Fe(II)′ was formed at a higher rate. The rate of Fe(II)′ produced during the experiment was explained by the kinetic model. The model confirmed that both the ligand/Fe ratio and incubation time have a significant effect on the pathway via which Fe(II)′ is formed from Fe(III)-fulvic acid complexes. 相似文献
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介绍了欧洲近几年浅层(特)高分辩地震勘探的发展现状，浅层(特)高分辩地震勘探中存在的主要技术难点与解决途径，其特制的采集设备与经验参数的设置情况，以及浅层高分辩地震勘探在冰川侵蚀古河道、溶洞、管道、表层地层结构的部分应用实例。 相似文献
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Odette Conchon 《Quaternary Research》1978,9(1):41-53
Fluvial, glacial, and colluvial deposits in Corsica have been studied in terms of their distribution, soils, sedimentology (arrangement, shape analysis, size analysis, petrography, and weathering of pebbles; size distribution, shape analysis, and mineralogy of matrix), and relationships to marine sediments. A relative chronology is based on the topographic and stratigraphic relationships between the sediments, and to a large extent on their degree of weathering. The intensity and the type of pebble weathering suggest a possible correlation of the older alluvial units with the Alpine Quaternary succession. Quaternary paleoclimates in Corsica alternated between glacial and interglacial. During glacial stages, when glaciers developed in the high mountains and formed tongues in the valleys, periglacial climates characterized the low altitude zone. Tectonic movements occurred in Corsica during the Quaternary, probably until the Middle Würm. 相似文献
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Numerous tornadoes have traversed southern Apulia in the course of the last five centuries, causing severe damage and a significant loss of life. Historical chronicles and newspaper articles allowed more than 30 tornadic events to be identified; in particular, 26 of these have occurred during the last two centuries. In all, 24 small towns and villages of southern Apulia suffered on at least one occasion the disastrous effects of being hit by a tornado.Collated data reveals that tornadoes generally form from May to December, with the most powerful events taking place in the month of September, followed by October and November. Tornadoes generally cluster in the southernmost area of the region and typically follow a path leading from the south-west to the north-east. Path length were observed to vary from 8 to 73km, and widths ranging from 60 to 850m.The metereological analysis carried out for the events occurred after 1950, even if based on a limited data set, reveals a few typical meteorological scenarios associated with the development of tornadoes over Salento.In southern Apulia tornadoes can be classified from levels A2 to A4 in accordance with the Damage Area Scale. 相似文献