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941.
The paper considers the extent to which social–ecological systems research might contribute to an improved understanding of the social and environmental impacts of teleconnections inherent in economic globalisation. Recognising the importance and specificity of regional interconnections, wherein actions in certain parts of the world impact quite specifically on the sustainability of certain other spatially distant places and systems, the paper reflects on the social and environmental implications of increasingly interconnected agri-food systems and intersecting global commodity chains. Key elements of social–ecological systems approaches, which have purported relevance to research on globalisation, are critically examined, and aspects of social–ecological systems thinking that pose challenges for its application in this context are considered. Wider implications and limitations of social–ecological systems approaches to research and practice in (global) governance for sustainability are discussed. The general conclusion is that social–ecological systems research may offer insights into the governance of social and environmental impacts of agri-food systems and other complex systems at certain scales. However, the formal utility of concepts like resilience, vulnerability and adaptability becomes considerably less clear as research turns to analyses of larger, complex, globally teleconnected systems, where the main contribution of such concepts may lie in their metaphorical appeal to important aspects of interconnectivity and interdependence.  相似文献   
942.
In April 2006, Dubai Municipality established a broadband seismological network in Dubai Emirate, United Arab Emirates (UAE). This network was the first seismic network in UAE and consists of four remote seismic stations to observe local and regional seismic activity that may have an effect on Dubai Emirate and the surrounding areas. The network exchanges real-time data with the National Center of Meteorology and Seismology in Abu Dhabi, the Earthquake Monitoring Center in Oman and imports in real-time data from few Global Seismic Network stations, which increases the aperture of the network. In April 2012, Dubai Municipality installed an additional five free-field strong motion stations inside the urban area to estimate and publish real-time ShakeMaps for public and decision makers. Although the local seismic activity from April 2006 to June 2013 reflects low seismic activity with the Emirate, it indicates active tectonics in the relatively aseismic northern Oman Mountains region. A few inland clusters of micro-to-small earthquakes have been identified with the new network. A clear cluster of small-to-moderate earthquakes took place in the eastern part of UAE to the east of Masafi, while two clusters of micro-to-small earthquakes took place at Wadi Nazwa and northern Huwaylat. Focal mechanisms of few well recorded earthquakes in this region indicate normal faulting, generally trending NE in parallel to the transition shear zone between the collision at Zagros and the subduction at the Makran zone.  相似文献   
943.
The Liupanshan Arcuate Tectonic Belt (LATB) is located at the northeastern margin of the Qinghai–Tibet Plateau. Major strike-slip and thrust faults in the Liupanshan area are prominent Cenozoic structures, which are critical in understanding and reconstructing the tectonic deformation history. This paper not only provides detailed investigations on geometric and kinematic characteristics of these faults in the LATB, but also dates the faults’ movements by electron spin resonance (ESR). The LATB underwent a succession of compression, extension and again compression tectonic deformation processes since the Cenozoic. The Liupanshan Curved Faults first experienced sinistral strike-slip shear during 57–61 Ma. The Liupanshan Curved Faults responded to the deformation caused by the eastward escape of the Qinghai–Tibet Plateau and acted as the northeastern boundary of the deformation. Timing for the formation of the Liupanshan Curved Faults shows that the collision of the Indian and Eurasian plates must have occurred earlier than these faults’ activity because the latter is reflected the far-field effect of the collision.  相似文献   
944.
To constrain the tectonic evolution of the eastern segment of the Paleo-Asian Ocean, we conducted zircon U–Pb-Hf dating and whole-rock geochemical analyses for metasedimentary rocks from the Dongnancha Formation in the Huadian area in central Jilin Province, Northeastern (NE) China. Most detrital zircons from the metasedimentary rocks display clear oscillatory zoning and striped absorption in cathodoluminescence (CL) images and have Th/U ratios of 0.1–1.8, thus indicating a magmatic origin. U–Pb isotopic dating using LA-ICP-MS method for zircon samples from the metasedimentary rocks reveals that the depositional age can be constrained to the period between 250 and 222 Ma. Geochemical data reveal low to intermediate degrees of weathering of the source material and compositionally low to intermediate maturity. Detailed analyses of detrital zircon U–Pb-Hf geochronology and geochemistry show that these metasedimentary rocks are derived from a bidirectional provenance. The predominant derivation is from Permian–Early Triassic felsic-intermediate igneous rocks of central Jilin Province and adjacent regions in the northern margin of the North China Craton, although felsic-intermediate igneous rocks and continental material in the eastern segment of the Central Asian Orogenic Belt from the Cambrian–Carboniferous represent additional sources and minor amounts of Paleoproterozoic–Neoproterozoic material have been input from the North China Craton. A number of geochemical indicators and tectonic discrimination diagrams collectively indicate a continental island arc-active continental margin setting for the deposition of the protoliths of the metasedimentary rocks. The results of geochemical and geochronological analyses of the provenance and tectonic setting of the metasedimentary rocks indicate that the Dongnancha Formation was likely deposited in an intermountain basin in a post-orogenic fast uplift setting, suggesting that the final closure of the eastern segment of the Paleo-Asian Ocean in the Huadian area of central Jinlin Province likely occurred between the Early Triassic and Middle Triassic.  相似文献   
945.
Up until now, it has been assumed that oil in the Palaeozoic reservoirs of the Tazhong Uplift was derived from Upper Ordovician source rocks. Oils recently produced from the Middle and Lower Cambrian in wells ZS1 and ZS5 provide clues concerning the source rocks of the oils in the Tazhong Uplift, Tarim Basin, China. For this study, molecular composition, bulk and individual n-alkane δ13C and individual alkyl-dibenzothiophene δ34S values were determined for the potential source rocks and for oils from Cambrian and Ordovician reservoirs to determine the sources of the oils and to address whether δ13C and δ34S values can be used effectively for oil–source rock correlation purposes. The ZS1 and ZS5 Cambrian oils, and six other oils from Ordovician reservoirs, were not significantly altered by TSR. The ZS1 oils and most of the other oils, have a “V” shape in the distribution of C27–C29 steranes, bulk and individual n-alkane δ13C values predominantly between −31‰ to −35‰ VPDB, and bulk and individual alkyldibenzothiophene δ34S values between 15‰ to 23‰ VCDT. These characteristics are similar to those for some Cambrian source rocks with kerogen δ13C values between −34.1‰ and −35.3‰ and δ34S values between 10.4‰ and 21.6‰. The oil produced from the Lower Ordovician in well YM2 has similar features to the ZS1 Cambrian oils. These new lines of evidence indicate that most of the oils in the Tazhong Uplift, contrary to previous interpretations, were probably derived from the Cambrian source rocks, and not from the Upper Ordovician. Conversely, the δ13C and δ34S values of ZS1C Cambrian oils have been shown to shift to more positive values due to thermochemical sulfate reduction (TSR). Thus, δ13C and δ34S values can be used as effective tools to demonstrate oil–source rock correlation, but only because there has been little or no TSR in this part of the section.  相似文献   
946.
In this paper, a stochastic approach for obtaining damage-based inelastic seismic spectra is proposed. The Park and Ang damage model, which includes displacement ductility and hysteretic energy, is adopted to take into account the cumulative damage phenomenon in structural systems under strong ground motions. Differently from previous studies in this field, damage-based seismic spectra are obtained by means of peak theory of stochastic processes. The following stochastic inelastic seismic spectra are constructed and then analyzed: damage-based displacement and acceleration inelastic spectra, damage-based response modification factor spectra, damage-based yield strength demand spectra and damage-based inelastic displacement ratio spectra.  相似文献   
947.
The purpose of this study is the evaluation of dynamic behavior induced by seismic activity on a silo system, containing bulk material, with a soil foundation. The interaction effects between the silo and bulk material, as well as the effects produced between the foundation of the silo and the soil, were taken into account. Proposed simplified approximation, as well as the finite model, were used for analysis. The results, from the presented approximation, were compared with a more rigorous obtainment method. Initially, the produced simplified approximation, with elastic material assumption for the grain, could determine the pressures on the dynamic material along with displacements along the height of the silo wall and base shear force, etc., with remarkable precision. Some comparisons, via a change of soil and/or foundation conditions, were also made regarding the seismic pressure of the dynamic material pressure, displacement and base shear forces for both squat and slender silos. Comparing the analytical predictions to results from the numerical simulations produced good results. It can be concluded that the model can be used effectively to perform a broad suite of parametric studies, not only at the design stage but also as a reliable tool for predicting system behavior under the limit state of the system. The results and comprehensive analysis show that displacement effects and base shear forces generally decreased when soil was softer; however, soil structure interaction (SSI) did not have any considerable effects on squat silos and therefore need not be taken into practice.  相似文献   
948.
Energy system pathways which are projected to deliver minimum possible deployment cost, combined with low Greenhouse Gas (GHG) emissions, are usually considered as ‘no-regrets’ options. However, the question remains whether such energy pathways present ‘no-regrets’ when also considering the wider environmental resource impacts, in particular those on land and water resources. This paper aims to determine whether the energy pathways of the UK’s Carbon Plan are environmental “no-regrets” options, defined in this study as simultaneously exhibiting low impact on land and water services resulting from resource appropriation for energy provision. This is accomplished by estimating the land area and water abstraction required by 2050 under the four pathways of the Carbon Plan with different scenarios for energy crop composition, yield, and power station locations. The outcomes are compared with defined limits for sustainable land appropriation and water abstraction.The results show that of the four Carbon Plan pathways, only the “Higher Renewables, more energy efficiency” pathway is an environmental “no-regrets” option, and that is only if deployment of power stations inland is limited. The study shows that policies for future low-carbon energy systems should be developed with awareness of wider environmental impacts. Failing to do this could lead to a setback in achieving GHG emission reductions goals, because of unforeseen additional competition between the energy sector and demand for land and water services in other sectors.  相似文献   
949.
The Haisugou Mo deposit is located in the northern part of the Xilamulun Mo–Cu metallogenic belt in northeastern China. The Mo mineralization mainly occurs as quartz-molybdenite veins within the Haisugou granite, which was emplaced into rocks of the Early Permian Qingfengshan Formation. Zircon U–Pb dating by LA–ICP-MS of the granite yields a crystallization age of 137.6 ± 0.9 Ma, suggesting emplacement during the peak time of Mo mineralization in eastern China, broadly constrained to ca. 150–130 Ma, when tectonic stresses shifted from compression to extension. Whole-rock geochemical data suggest that the granite belongs to the high-K calc-alkaline series, and is characterized by relatively high LREE; low HREE; depletion of Ti, Ba, and Nb; and a moderate negative Eu anomaly. The zircon εHf(t) and whole-rock εNd(t) values for the intrusion range from +4.5 to +10.0 and +0.2 to +1.6, respectively, indicating that the magma originated from the juvenile lower crust source derived from depleted mantle, with some component of ancient continental crust. The granite is also characterized by initial (87Sr/86Sr)i ratios ranging from 0.7040 to 0.7074, which suggest some contamination by the upper crust during the ascent of the primitive magma. Moreover, it can be recognized from the whole-rock major and trace element data that significant fractional crystallization occurred during magmatic evolution, with the separation of plagioclase and K-feldspar. Because Mo is an incompatible element and tends to concentrate in the melt during crystallization, fractionation processes likely played an important role in the formation of the Haisugou Mo deposit.  相似文献   
950.
In porous media, the dynamics of the invading front between two immiscible fluids is often characterized by abrupt reconfigurations caused by local instabilities of the interface. As a prototype of these phenomena we consider the dynamics of a meniscus in a corner as it can be encountered in angular pores. We investigate this process in detail by means of direct numerical simulations that solve the Navier–Stokes equations in the pore space and employ the Volume of Fluid method (VOF) to track the evolution of the interface. We show that for a quasi-static displacement, the numerically calculated surface energy agrees well with the analytical solutions that we have derived for pores with circular and square cross sections. However, the spontaneous reconfigurations are irreversible and cannot be controlled by the injection rate: they are characterized by the amount of surface energy that is spontaneously released and transformed into kinetic energy. The resulting local velocities can be orders of magnitude larger than the injection velocity and they induce damped oscillations of the interface that possess their own time scales and depend only on fluid properties and pore geometry. In complex media (we consider a network of cubic pores) reconfigurations are so frequent and oscillations last long enough that increasing inertial effects leads to a different fluid distribution by influencing the selection of the next pore to be invaded. This calls into question simple pore-filling rules based only on capillary forces. Also, we demonstrate that inertial effects during irreversible reconfigurations can influence the work done by the external forces that is related to the pressure drop in Darcy’s law. This suggests that these phenomena have to be considered when upscaling multiphase flow because local oscillations of the menisci affect macroscopic quantities and modify the constitutive relationships to be used in macro-scale models. These results can be extrapolated to other interface instabilities that are at the origin of fast pore-scale events, such as Haines jumps, snap-off and coalescence.  相似文献   
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