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1.
A model for the conservation of geological remains as documents   总被引:1,自引:0,他引:1  
 Geological remains are conserved mainly either together with living beings for the sake of the integrity of nature or for their economical or aesthetic value. However, they also have scientific value for the geologist to reconstruct the earth's past. For this reason we propose a model which is an application of marginal utility theory in economics and takes into account the informational utility of geological remains. Informational utility of geological remains ranges over their geological significance which is induced by the importance of the geological processes that produce them, and over their spatial extensiveness. Our model takes into account also the cost and budget of conservation and proposes to solve the differential equations of informational utility and cost simultaneously in order to obtain the optimum quantity of the remains to be conserved. Received: 9 January 1998 · Accepted: 4 February 1998  相似文献   

2.
In the last decades, employment policy design and implementation partly shifted from the national to local and regional scales in most European countries. In addition, the European Union appeared as an important new actor in this policy field in the late 1990s. We argue that the new geographical multi-scaling of employment policy can be used strategically by feminists to promote different aspects of gender equality simultaneously: Feminist claims related to gender equity, i.e., demands to secure equal participation of women and men in the labour market, should be advocated at the national scale. Claims related to the recognition of gender difference, i.e., demands related to typical female and male employment needs and their social recognition should be promoted at the local scale. The regional scale is the most appropriate one to advance gender plurality, i.e., non-traditional employment of women and men. In the empirical part of the paper we discuss how the ideal leverage of claims at different spatial scales and inter-linkage between scales could operate. We will show that the link to EU policy strengthens feminist claims in the highly gender-differentiated societies and political settings of Austria and Germany. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

3.
We found a characteristic space–time pattern of the tidal triggering effect on earthquake occurrence in the subducting Philippine Sea plate beneath the locked zone of the plate interface in the Tokai region, central Japan, where a large interplate earthquake may be impending. We measured the correlation between the Earth tide and earthquake occurrence using microearthquakes that took place in the Philippine Sea plate for about two decades. For each event, we assigned the tidal phase angle at the origin time by theoretically calculating the tidal shear stress on the fault plane. Based on the distribution of the tidal phase angles, we statistically tested whether they concentrate near some particular angle or not by using Schuster's test. In this test, the result is evaluated by p-value, which represents the significance level to reject the null hypothesis that earthquakes occur randomly irrespective of the tidal phase angle. As a result of analysis, no correlation was found for the data set including all the earthquakes. However, we found a systematic pattern in the temporal variation of the tidal effect; the p-value significantly decreased preceding the occurrence of M ≥ 4.5 earthquakes, and it recovered a high level afterwards. We note that those M ≥ 4.5 earthquakes were considerably larger than the normal background seismicity in the study area. The frequency distribution of tidal phase angles in the pre-event period exhibited a peak at the phase angle where the tidal shear stress is at its maximum to accelerate the fault slip. This indicates that the observed small p-value is a physical consequence of the tidal effect. We also found a distinctive feature in the spatial distribution of p-values. The small p-values appeared just beneath the strongly coupled portion of the plate interface, as inferred from the seismicity rate change in the past few years.  相似文献   

4.
Alec Brownlow 《Geoforum》2005,36(5):581-592
Men are at significantly greater risk than women to violent crime victimization in the US, especially in the public sphere. Despite this, their fears and vulnerabilities have received considerably less attention in recent social discourse than have women. Men’s risk in, and fear of, public space is overshadowed by their apparent fearlessness in public space. This paper begins to address this apparent paradox using the conceptual lenses of masculinity and control. I explore fear and fearlessness among men as objects and subjects of masculinity. Stated fearlessness among men is counterbalanced by a chronic fear of violent crime victimization. Conditioned fearlessness combines with actual risk and chronic fear to shape men’s experiences in the public sphere. I study the dynamics of men’s fear using data gathered from a group of young men and women in Philadelphia. Gendered differences in fear and how environments are perceived and judged as to their relative safety are demonstrated and explored. Compared to women’s fears and perceived geographical vulnerabilities, the men of this study demonstrate a persistent and chronic wariness of their environmental context that precedes any judgment of perceived safety. Violence and fear among both men and women in this study is further explained as a function of racism and economic marginalization.  相似文献   

5.
We conducted a study of the spatial distributions of seismicity and earthquake hazard parameters for Turkey and the adjacent areas, applying the maximum likelihood method. The procedure allows for the use of either historical or instrumental data, or even a combination of the two. By using this method, we can estimate the earthquake hazard parameters, which include the maximum regional magnitude max, the activity rate of seismic events and the well-known value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship. These three parameters are determined simultaneously using an iterative scheme. The uncertainty in the determination of the magnitudes was also taken into consideration. The return periods (RP) of earthquakes with a magnitude M ≥ m are also evaluated. The whole examined area is divided into 24 seismic regions based on their seismotectonic regime. The homogeneity of the magnitudes is an essential factor in such studies. In order to achieve homogeneity of the magnitudes, formulas that convert any magnitude to an MS-surface scale are developed. New completeness cutoffs and their corresponding time intervals are also assessed for each of the 24 seismic regions. Each of the obtained parameters is distributed into its respective seismic region, allowing for an analysis of the localized seismicity parameters and a representation of their regional variation on a map. The earthquake hazard level is also calculated as a function of the form Θ = (max,RP6.0), and a relative hazard scale (defined as the index K) is defined for each seismic region. The investigated regions are then classified into five groups using these parameters. This classification is useful for theoretical and practical reasons and provides a picture of quantitative seismicity. An attempt is then made to relate these values to the local tectonics.  相似文献   

6.
As an application, we demonstrate a proposed variogram modeling scheme using a spatial data set. Because the scheme relies on a procedure for simultaneously diagonalizing several matrices, we briefly describe the FG and least-squares algorithms. The model obtained by our scheme is used to cokrige the data. In addition, the proposed scheme is compared to more traditional methods.  相似文献   

7.
The Upper Cretaceous La Cova limestones (southern Pyrenees, Spain) host a rich and diverse larger foraminiferal fauna, which represents the first diversification of K-strategists after the mass extinction at the Cenomanian–Turonian boundary.The stratigraphic distribution of the main taxa of larger foraminifera defines two assemblages. The first assemblage is characterised by the first appearance of lacazinids (Pseudolacazina loeblichi) and meandropsinids (Eofallotia simplex), by the large agglutinated Montsechiana montsechiensis, and by several species of complex rotalids (Rotorbinella campaniola, Iberorotalia reicheli, Orbitokhatina wondersmitti and Calcarinella schaubi). The second assemblage is defined by the appearance of Lacazina pyrenaica, Palandrosina taxyae and Martiguesia cyclamminiformis.A late Coniacian-early Santonian age was so far accepted for the La Cova limestones, based on indirect correlation with deep-water facies bearing planktic foraminifers of the Dicarinella concavata zone. Strontium isotope stratigraphy, based on many samples of pristine biotic calcite of rudists and ostreids, indicates that the La Cova limestones span from the early Coniacian to the early-middle Santonian boundary. The first assemblage of larger foraminifera appears very close to the early-middle Coniacian boundary and reaches its full diversity by the middle Coniacian. The originations defining the second assemblage are dated as earliest Santonian: they represent important bioevents to define the Coniacian-Santonian boundary in the shallow-water facies of the South Pyrenean province.By means of the calibration of strontium isotope stratigraphy to the Geological Time Scale, the larger foraminiferal assemblages of the La Cova limestones can be correlated to the standard biozonal scheme of ammonites, planktonic foraminifers and calcareous nannoplankton. This correlation is a first step toward a larger foraminifera standard biozonation for Upper Cretaceous carbonate platform facies.  相似文献   

8.
The Last Picture Show does not fall within the genre of the Western, yet the cinematic narrative mourns the loss of the iconic Westerner — a man — and the passing of his home places that constitute the Old West. This paper is concerned with the ways in which this man and his places are transformed along with the embryonic but inexorable emergence of the New West — and its attendant demand for recognition of hitherto unheard voices (e.g., women, Latinos) — that accompanied significant social, cultural and political shifts that were beginning to emerge within the country as a whole in the represented early 1950s. His represented sites of contestation are found within the frame of the small west Texas town of Anarene, created by Larry McMurtry's novel of the same name as the film, both of which reflect contexts of the era in which they were constructed — the mid 1960s to early 1970s. We suggest that the film shows a great sensitivity to the ways in which particular masculinities are constituted in specific places, to the tensions that arise from the changing nature and definitions of masculinity as they are linked to these places, and with his sense of nostalgia and loss that accompanies his inevitable decline. But there is no clear and empowered place for women in these new places, only a recontextualized form of a patriarchal order which is not relational and which still maintains essentialist assumptions of gender. The Old West has taken new shape, much to the chagrin of man, but it is hardly a New West, with its emerging and representative voices. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

9.
John Ogden Dr. 《GeoJournal》1988,17(2):225-230
Emphasis is placed on the role synchronised cohort mortality in the dynamics of beech (Nothofagus) forest in New Zealand. Mature populations are frequently relatively even-aged and have size structures which render them vulnerable to exogenous disturbances from which they cannot recover, except by regeneration. Examples of regeneration systems in pure and mixed stands are described. Mountain beech (N. solandri var.cliffortioides) is a relatively short-lived light demanding species largely dependent upon exogenous canopy destruction for regeneration. Red beech (N. fusca) is a larger longer-lived tree which can maintain its population by autonomous gap-phase regeneration. When these species grow in mixture with silver beech (N. menziesii) in the absence of disturbance, they seem destined to be replaced by it, because silver beech is more shade tolerant and longer-lived. Thus, factors promoting stand synchrony are important for mountain and red beech, because if large scale canopy opening does not occur, sites are more likely to be lost to competitors. Cohort synchrony is associated also with physiological synchrony between individuals. Consequently periodic stresses, such as mast seeding, may affect almost all individuals. Storm damage and drought years are implicated. If only a few individuals (or even parts of individuals) die, this can lead to rapid stand decline, and subsequent large scale regeneration.  相似文献   

10.
11.
To reveal the effect of shale reservoir characteristics on the movability of shale oil and its action mechanism in the lower third member of the Shahejie Formation(Es3l), samples with different features were selected and analyzed using N2 adsorption, high-pressure mercury injection capillary pressure(MICP), nuclear magnetic resonance(NMR), high-speed centrifugation, and displacement image techniques. The results show that shale pore structure characteristics control shale oil movability directly. Movable oil saturation has a positive relationship with pore volume for radius > 2 μm, as larger pores often have higher movable oil saturation, indicating that movable oil is present in relatively larger pores. The main reasons for this are as follows. The relatively smaller pores often have oil-wetting properties because of organic matter, which has an unfavorable effect on the flow of oil, while the relatively larger pores are often wetted by water, which is helpful to shale oil movability. The rich surface provided by the relatively smaller pores is beneficial to the adsorption of immovable oil. Meanwhile, the relatively larger pores create significant pore volume for movable oil. Moreover, the larger pores often have good pore connectivity. Pores and fractures are interconnected to form a complex fracture network, which provides a good permeability channel for shale oil flow. The smaller pores are mostly distributed separately;thus, they are not conducive to the flow of shale oil. The mineral composition and fabric macroscopically affect the movability of shale oil. Calcite plays an active role in shale oil movability by increasing the brittleness of shale and is more likely to form micro-cracks under the same stress background. Clay does not utilize shale oil flow because of its large specific surface area and its block effect. The bedding structure increases the large-scale storage space and improves the connectivity of pores at different scales, which is conducive to the movability of shale oil.  相似文献   

12.
We consider groundwater steady flow in a heterogeneous porous formation of random and stationary log-conductivity Y = ln K, characterized by the mean 〈Y〉, and the two point correlation function C Y which in turn has finite, and different horizontal and vertical integral scales I and I v , respectively. The fluid velocity V, driven by a given head drop applied at the boundary, has constant mean value U ≡ (U, 0, 0). Approximate explicit analytical expressions for transverse velocity covariances are derived. The adopted methodology follows the approach developed by Dagan and Cvetkovic (Spatial moments of kinetically sorbing plume in a heterogeneous aquifers, Water Resour. Res. 29 (1993) 4053) to obtain a similar result for the longitudinal velocity covariance. Indeed, the approximate covariances of transverse velocities are determined by requiring that they have the exact first order variances as well as zero integral scale (G. Dagan, Flow and Transport in Porous Formations (Springer, 1989)) , and provide the exact asymptotic limits of the displacement covariance of the fluid particles obtained by Russo (On the velocity covariance and transport modeling in heterogeneous anisotropic porous formations 1. Saturated flow, Water Resour. Res., 31 (1995) 129). Comparisons with numerical results show that the proposed expressions compare quite well in the early time regime, and for Ut/I >100. Since most of the applications, like assessing the effective mobility of contaminants or quantifying the potential hazards of nuclear repositories, require predictions over higher times the proposed approximate expressions provide acceptable results. The main advantage related to such expressions is that they allow obtaining closed analytical forms of spatial moments pertaining to kinetically sorbing contaminant plumes avoiding the very heavy computational effort which is generally demanded. For illustration purposes, we consider the movement of one contaminant species, and show how our approximate spatial moments compare with the numerical simulations.  相似文献   

13.
肖斌  潘懋  赵鹏大  侯景儒 《地质科学》2001,36(4):500-508
空间信息统计学是一门集数学、空间信息科学及计算机技术于一体,在时空域内对区域化变量的随机性与结构性进行定量研究的技术。以山东归来庄金矿床为例,对其g(AuAg)异常进行空间信息统计学研究。利用指示克立格法研究g(AuAg)的空间变异结构特征,建立空间结构模型。在对结构模型和估计方案进行交叉验证后,对g(AuAg)的空间分布进行估计。根据g(AuAg)的空间分布规律,探讨其与Au空间分布的关系,并对今后该区的找金工作提出建议。  相似文献   

14.
The Kristallbrocken are a characteristic centimetre- to decimetre-sized, laminated halite fabric type occurring in the Stassfurt Formation in the Zechstein Basin. Up to now, the nature of the Kristallbrocken, i.e. if they are relics of fine-grained, polycrystalline halite beds or clasts of ‘single crystal-layers’, as well as the deformation mechanisms of this halite type, were not clear from the literature. Drill core material from the salt deposit Teutschenthal at the southern rim of the Zechstein Basin now allowed investigating less intensely deformed samples for the first time. The deformational behaviour of these Kristallbrocken ranges from brittle to ductile, which is evidenced by fractured Kristallbrocken on the one hand and weakly bent or even folded Kristallbrocken on the other hand. Local X-ray texture measurements demonstrated that the Kristallbrocken are definitely single crystals and that they can be regarded as relics of formerly larger ‘single crystal-layers’ of up to several dm2 in size. The folded Kristallbrocken clearly display by their single grain texture characteristics that their crystal lattice is bent, which was most likely enabled by a kind of flexural-shear folding, and did not develop after deformation from a fine-grained aggregate by recrystallisation. Due to their monocrystallinity, their originally large size, and the solid inclusions forming the internal lamination, the Kristallbrocken have clearly stronger rheological properties than the surrounding fine- to coarse-grained polycrystalline rock salt, and thus also deform by fracturing.  相似文献   

15.
The bivalve Pisidium amnicum (Müller 1774) is a common species in several European freshwater ecosystems. However, few Iberian watersheds are colonized by this species, and the River Minho estuary is possibly the Iberian aquatic ecosystem with the larger population. In October 2004–2007, investigations on spatial and temporal variations in P. amnicum abundance and biomass were carried out at 16 sites along the River Minho tidal freshwater wetlands. Mean abundance and biomass per site ranged from 0 to 750 ind m−2 and 0 to 7.42 g AFDW m−2, respectively. A clear decrease in the spatial distribution, abundance, and biomass was observed during the 4-year assessment. Furthermore, a stepwise multiple regression model showed that organic matter and conductivity explained 50.2% of the variation in P. amnicum abundance (R 2 = 0.502, F [2, 15] = 7.569, p = 0.005). Ecological knowledge is essential to the implementation of future conservation plans for P. amnicum, and the results of this study are of paramount importance to identify habitats that should be protected in order to preserve this species and provide scientific reference that may be useful in the development of management and/or restoration plans.  相似文献   

16.
Is the ocean floor a fractal?   总被引:1,自引:0,他引:1  
The topographic structure of the ocean bottom is investigated at different scales of resolution to answer the question: Can the seafloor be described as a fractal process? Methods from geostatistics, the theory of regionalized variables, are used to analyze the spatial structure of the ocean floor at different scales of resolution. The key to the analysis is the variogram criterion: Self-similarity of a stochastic process implies self-similarity of its variogram. The criterion is derived and proved here: it also is valid for special cases of self-affinity (in a sense adequate for topography). It has been proposed that seafloor topography can be simulated as a fractal (an object of Hausdorff dimension strictly larger than its topological dimension), having scaling properties (self-similarity or self-affinity). The objective of this study is to compare the implications of these concepts with observations of the seafloor. The analyses are based on SEABEAM bathymetric data from the East Pacific Rise at 13°N/104°W and at 9°N/104°W and use tracks that run both across the ridge crest and along the ridge flank. In the geostatistical evaluation, the data are considered as a stochastic process. The spatial continuity of this process is described by variograms that are calculated for different scales and directions. Applications of the variogram criterion to scale-dependent variogram models yields the following results: Although the seafloor may be a fractal in the sense of the definition involving the Hausdorff dimension, it is not self-similar, nor self-affine (in the given sense). Mathematical models of scale-dependent spatial structures are presented, and their relationship to geologic processes such as ridge evolution, crust formation, and sedimentation is discussed.  相似文献   

17.
Ali. O. Oncel  Tom Wilson   《Tectonophysics》2006,418(3-4):205-218
Seismotectonic parameters including the Gutenberg-Richter b-value and multifractal dimensions D2 and D15 of seismicity patterns (both spatial and temporal) were compared to GPS-derived maximum shear and dilatation strains measured in the Marmara Sea region of western Turkey along the Northern Anatolian Fault Zone (NAFZ). Comparisons of seismotectonic parameters and GPS-derived maximum shear and dilatation strain along the NAFZ in the vicinity of the 1999 M7.4 Izmit earthquake reveal a positive correlation (r = 0.5, p = 0.05) between average dilatation and the Gutenberg-Richter b-value. Significant negative correlation (r = − 0.56, p = 0.03 and r = − 0.56, p = 0.02) was also observed between the spatial fractal dimension D2 and GPS-derived maximum geodetic and shear strain. This relationship suggests that, as maximum geodetic and shear strains increase, seismicity becomes increasingly clustered.Anomalous interrelationships are observed in the Marmara Sea region prior to the Izmit event along a bend in the NAFZ near the eastern end of the Marmara Sea known as the Northern Boundary Fault (NBF). An asperity is located near the northwest end of the NBF. Along the 50-km length of the NBF, GPS strains become slightly compressive. The correlation between b-value and GPS-derived dilatation suggests that regions in compression have increased probability of larger magnitude rupture. The NBF appears to serve as an impediment to the transfer of strain from east to west along the NAFZ. Recurrence times for large earthquakes along the NBF are larger than in surrounding areas. Temporal clustering of seismicity in the vicinity of the NBF may represent foreshocks of an impending rupture.  相似文献   

18.
More than 1000 near-circular mounds up to 40 m diameter and 2.1 m high, which contain 15–1250 m3 (mean 159 m3) of gravel, have been identified in western New South Wales. Mounds are more pebble-rich than the surrounding surface regolith and contain abundant pebbles to 1196 g weight. Resemblance to smaller gravel nest mounds of the malleefowl (Leipoa ocellata) suggests they were constructed by a similar although larger bird. Pebbles were inadvertently concentrated in the nest mounds during construction and maintenance. Formation by geological mechanisms, as burrow spoil or burial mounds is not compatible with the features of the mounds. The mounds are undated, but partial blanketing by eolian sand suggests they predate the Last Glacial Maximum. The mounds are now spatially associated with Casuarina trees. Pollen records in southeastern Australia reveal that shrub and grassland replaced Casuarina woodland as aridity increased after ca 35 000 yrs BP. Climate change driven habitat loss in the semi-arid zone likely caused the extinction of the apparently Casuarina woodland dependent megapode responsible for the gravel mounds. The mounds partly map the megapode distribution and provide an opportunity to date the local extinction of a megafauna member, compare this to climate and vegetation changes, and determine the duration of overlap with human occupation.  相似文献   

19.
Toward more realistic formulations for the analysis of laccoliths   总被引:1,自引:0,他引:1  
The published laccolith analyses are based on the linear plate bending theory and the a priori assumption that the width of the laccolith is fixed. This is not the case in an actual situation. The dimension of the laccolith in the horizontal plane has to result from an additional matching condition at the separation lines. The published analyses are generalized by dropping the a priori assumption that the width of the laccolith is prescribed, by assuming that the magmatic pressure is not constant, and by taking into consideration the vertical compressibility of the overburden “plate” and base in the contact region. In order to determine the magnitude of the magmatic pressure, a condition is postulated that equates the measured volume of the intruded magma in a laccolith with the corresponding analytical expression for the volume. The obtained closed-form solution appears to satisfy many of the intuitive expectations. It was evaluated numerically and the results are presented as graphs. It may be concluded that even very small laccoliths may exist, provided the magmatic pressure is sufficiently larger than the overburden weight. We also show the dependence of the laccolith size on its stratigraphic position; the thicker the overburden h the larger the size of the laccolith, for an overburden plate of given thickness, the larger the volume V of the intruded magma, the larger the laccolith width 2a and its height. The paper concludes by discussing a published analysis for laccolith with flexible underburden and overburden. It is shown that this analysis is based on a formulation that is of questionable validity.  相似文献   

20.
Anna Notaro 《GeoJournal》2000,51(1-2):15-22
The aim of this paper is to show how fascist imperialist discourses were articulated in a new urban space, just on the outskirts of Rome, and how they affected its design, use and representation. This new city, which should have been the spatial expression of the regime's political, cultural and economical achievements, since its beginning was conceived almost as a mirror image of classical Rome. As her fascist alter-ego, it was imagined as the modern realisation of the ancient dream of reconnecting Rome to the Mediterranean, of bringing Rome to the sea and the sea to Rome, as Mussolini used to say. This was a city that had to represent a strong political desire and ended up as an image of mere representation, a city that was founded to contain a world exhibition and became in itself merely an exhibit. Here I am interested not only in the story the EUR (Esposizione Universale di Roma) buildings tell, but also in what they do, according to a performative view of cultural production. In other words, they are not simply new monuments to be added to Fascism's already powerful iconography, but an integral part of those processes of incorporation and rule at work in the construction of Italy's national/imperial identity.  相似文献   

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