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991.
Nina Kyllingstad Jan Ole Rypestøl 《Norsk geografisk tidsskrift. Norwegian journal of geography》2019,73(1):29-38
ABSTRACTDue to increased attention on environmental issues, industrial sustainable restructuring is high on the research agenda. The article adds to the literature through an analysis of a restructuring process within a Norwegian process industry cluster. By introducing an analytical framework combining the concepts of entrepreneurial discovery process and path dependency theory, the article offers a deeper understanding of the role of various types of actors in processes of restructuring. The authors categorise the actors as either firm-level entrepreneurs or system-level entrepreneurs on the basis of their motivation. While the former are motivated mainly by firm success, the latter find their motivation mainly in developing systemic factors. The analytical framework suggests a stepwise analysis of the restructuring, and in each step, the significance and interplay between the two types of entrepreneurs are discussed. Finally, the authors discuss the potential for new path development following from this process. The case study illustrates the important role of system-level entrepreneurs as facilitators and of firm-level entrepreneurs as utilisers of opportunities. The empirical case demonstrates that the two types of entrepreneurs are highly interactive throughout the restructuring process. The article contributes to existing literature by advancing the actor perspective in new path development. 相似文献
992.
Jaroslav Lexa Ioan Seghedi Karoly Németh Alexandru Szakács Vlastimil Koneĉny Zoltan Pécskay Alexandrina Fülöp Marinel Kovacs 《Central European Journal of Geosciences》2010,2(3):207-270
Neogene to Quaternary volcanic/magmatic activity in the Carpathian-Pannonian Region (CPR) occurred between 21 and 0.1 Ma with a distinct migration in time from west to east. It shows a diverse compositional variation in response to a complex interplay of subduction with rollback, back-arc extension, collision, slab break-off, delamination, strike-slip tectonics and microplate rotations, as well as in response to further evolution of magmas in the crustal environment by processes of differentiation, crustal contamination, anatexis and magma mixing. Since most of the primary volcanic forms have been affected by erosion, especially in areas of post-volcanic uplift, based on the level of erosion we distinguish: (1) areas eroded to the basement level, where paleovolcanic reconstruction is not possible; (2) deeply eroded volcanic forms with secondary morphology and possible paleovolcanic reconstruction; (3) eroded volcanic forms with remnants of original morphology preserved; and (4) the least eroded volcanic forms with original morphology quite well preserved. The large variety of volcanic forms present in the area can be grouped in a) monogenetic volcanoes and b) polygenetic volcanoes and their subsurface/intrusive counterparts that belong to various rock series found in the CPR such as calc-alkaline magmatic rock-types (felsic, intermediate and mafic varieties) and alkalic types including K-alkalic, shoshonitic, ultrapotassic and Na-alkalic. The following volcanic/subvolcanic forms have been identified: (i) domes, shield volcanoes, effusive cones, pyroclastic cones, stratovolcanoes and calderas with associated intrusive bodies for intermediate and basic calclkaline volcanism; (ii) domes, calderas and ignimbrite/ash-flow fields for felsic calc-alkaline volcanism and (iii) dome flows, shield volcanoes, maars, tuffcone/tuff-rings, scoria-cones with or without related lava flow/field and their erosional or subsurface forms (necks/ plugs, dykes, shallow intrusions, diatreme, lava lake) for various types of K- and Na-alkalic and ultra-potassic magmatism. Finally, we provide a summary of the eruptive history and distribution of volcanic forms in the CPR using several sub-region schemes. 相似文献
993.
The end of the Messinian Salinity Crisis in the western Mediterranean: Insights from the carbonate platforms of south-eastern Spain 总被引:1,自引:0,他引:1
Raphaël Bourillot Emmanuelle Vennin Jean-Marie Rouchy Marie-Madeleine Blanc-Valleron Antonio Caruso 《Sedimentary Geology》2010,229(4):224-485
How the Messinian Salinity Crisis (MSC) ended is still a matter of intense debate. The Terminal Carbonate Complex (TCC) is a late Messinian carbonate platform system that recorded western Mediterranean hydrological changes from the final stages of evaporite deposition till the advent of Lago-Mare fresh- to brackish water conditions at the very end of Messinian times. A multidisciplinary study has been carried out in three localities in south-eastern Spain to reconstruct the history of TCC platforms and elucidate their significance in the MSC. Overall, this study provides evidence that the TCC formed following a regional 4th order water level rise and fall concomitant with an opening-restriction trend. It can be subdivided into four 5th order depositional sequences (DS1 to DS4) recording two phases: (1) from DS1 to DS3, a tide-dominated ooidic to oobioclastic system with stenohaline faunas developed as a result of a 70 m water level rise. During this period, the TCC developed in a shallow sea with close to normal marine salinity; (2) in depositional sequence 4, a microbialite-dominated platform system developed. This is indicative of a significant environmental change and is attributed to a 30 to 40 m water level fall in the basins under study. These restricted conditions were coeval with intense evaporite deformation and brine recycling. The syn-sedimentary deformation of evaporites had a major impact on platform architecture and carbonate production, affecting the Messinian series throughout south-eastern Spain at the end of the TCC history. At that time, the TCC developed in a lake with fluctuating, brackish- to hypersaline water. These findings suggest a temporary restoration of marine conditions in the western Mediterranean marginal basins due to Atlantic water influxes prompted by a global sea level rise around 5.6 Ma. Whether marine conditions extended to the entire western Mediterranean still needs to be investigated. 相似文献
994.
Urban hydrologic trend analysis based on rainfall and runoff data analysis and conceptual model calibration
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Urban stormwater is a major cause of urban flooding and natural water pollution. It is therefore important to assess any hydrologic trends in urban catchments for stormwater management and planning. This study addresses urban hydrological trend analysis by examining trends in variables that characterize hydrological processes. The original and modified Mann‐Kendall methods are applied to trend detection in two French catchments, that is, Chassieu and La Lechere, based on approximately 1 decade of data from local monitoring programs. In both catchments, no trend is found in the major hydrological process driver (i.e., rainfall variables), whereas increasing trends are detected in runoff flow rates. As a consequence, the runoff coefficients tend to increase during the study period, probably due to growing imperviousness with the local urbanization process. In addition, conceptual urban rainfall‐runoff model parameters, which are identified via model calibration with an event based approach, are examined. Trend detection results indicate that there is no trend in the time of concentration in Chassieu, whereas a decreasing trend is present in La Lechere, which, however, needs to be validated with additional data. Sensitivity analysis indicates that the original Mann‐Kendall method is not sensitive to a few noisy values in the data series. 相似文献
995.
Low‐P melting of metapelitic rocks and the role of H2O: Insights from phase equilibria modelling
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Alfonso M. Sola Pavlina Hasalová Roberto F. Weinberg Néstor O. Suzaño Raúl A. Becchio Fernando D. Hongn Nilson Botelho 《Journal of Metamorphic Geology》2017,35(9):1131-1159
Water‐fluxed melting has long been thought to have a minor influence on the thermal and chemical structure of the crust. We report here on amphibolite facies metasedimentary rocks from the 490–450 Ma Famatinian Orogen, in northwest Argentina, that have undergone water‐fluxed incongruent biotite melting at relatively low temperature, which have produced and lost a significant volume of melt. The protoliths consist of the turbiditic Puncoviscana Formation (Neoproterozoic to Early Cambrian). The field area exhibits a condensed metamorphic field gradient, from greenschist to amphibolite facies suprasolidus conditions, recording a low pressure almost isobaric path, reaching peak conditions estimated at 700°C at 4 kbar. Thermodynamic modelling in the MnNCKFMASHTO system is applied to investigate melting at such low pressure as a function of water content. Calculations using a typical turbidite composition show how small amounts of added free H2O may increase significantly the melt fraction with little or no change in either the melt or residual phase compositions. They indicate negligible difference in normative An–Ab–Or proportions and ferromagnesian contents between melts derived by dehydration and water‐fluxed melts. The same is true for the content of H2O dissolved in melts, which remains constant and the melt produced is granitic whether or not aqueous fluids are present. Thus, neither the residue nor the melt composition are indicators of the presence of aqueous fluids during anatexis. Recognizing the impact of small additions of H2O to an anatectic terrane may therefore be difficult. The most significant change related to water‐fluxing is the relative proportions of minerals and melt fraction, rather than the actual mineral assemblage. The modal proportion of feldspar decreased while those of cordierite and biotite increased in the residual assemblages, as <5 mol.% of free H2O was added. The impact of this addition is to more than double the proportion of water‐undersaturated melt to 25–30 mol.%. We have also developed a simple way to estimate how much melt a residual rock has lost, if the compositional trends of the protoliths are known. In summary, we find that even though the addition of small amounts of free H2O impacts significantly on rock fertility, there is little obvious record in the field. The combined application of careful petrological investigation and thermodynamic modelling is the key to identify the influence of aqueous fluids, and exploit systems that became open not only to fluid influx but also to the extraction of melt. 相似文献
996.
Pál Sümegi Sándor Gulyás Dávid Molnár Gábor Bozsó István Fekete László Makó Péter Cseh Mihály Molnár Balázs P. Sümegi Peter Almond Christian Zeeden Tünde Törőcsik Janina J. Nett András Markó Frank Lehmkuhl 《第四纪科学杂志》2021,36(8):1364-1381
The 10 m thick Madaras loess–palaeosol profile is one of the Hungarian outcrops that yielded Upper Palaeolithic artefacts in 1966. To clarify the nature of the deposits and establish a reliable litho- and chronostratigraphy, a profile was opened and sampled at 25 cm intervals on the northern side of the brickyard in 1975. Analyses focused on grain size, carbonate content and the mollusc fauna. The chronology was based on the mollusc composition and a single date from the archaeological layer at the depth of ca 7 m below the surface. The 1975 profile was destroyed by mining but the reposited samples allowed an extended analysis of this important Marine Isotope Stage 2 record to which archaeological features were directly assigned. A new absolute chronology was built based on 11 14C dates. Environmental magnetic, geochemical and palaeoecological investigations allowed a refined view of site evolution with reliable chronology for the Last Glacial Maximum. Our results corroborated those of previous investigations done on other coeval loess–palaeosol sequences of the Southern Carpathian Basin. This also allowed for a temporal correlation to another local record with the published high-resolution chronology of the same brickyard and enabled modelling of local-scale heterogeneity of the environment in the long run. 相似文献
997.
José Manuel Tunqui Neira Vazken Andréassian Gaëlle Tallec Jean-Marie Mouchel 《水文研究》2021,35(11):e14428
Concentration–discharge ( ) relationships are widely used to assess the link between hydrological and biogeochemical processes at the catchment scale. relationships are mainly calibrated using mono-objective methods to represent, either concentrations or discharge-weighted concentrations (i.e., load). Based on its wide use in hydrological modelling, we test a multi-objective calibration for the relationship parameters, using both concentration and load, and compare it to a mono-objective calibration applied on either concentrations or load. This work is carried out on a high-frequency dataset (ORACLE-Orgeval Observatory, France). Our findings show that the multi-objective calibration yield a better representation of relationships parameters during the high and low-flow events. The multi-objective calibration can be used for all forms of relationships and avoids issues of under-representation of dilution processes characterized by high-discharge, low-concentration periods. 相似文献
998.
Beatrice M.S. Giambastiani Nicolò Colombani Nicolas Greggio Marco Antonellini Micòl Mastrocicco 《水文研究》2017,31(8):1613-1621
With global warming and sea level rise, many coastal systems will experience increased levels of inundation and storm flooding, especially along sandy lowland coastal areas, such as the Northern Adriatic coast (Italy). Understanding how extreme events may directly affect groundwater hydrology in shallow unconfined coastal aquifers is important to assess coastal vulnerability and quantify freshwater resources. This study investigates shallow coastal aquifer response to storm events. The transitory and permanent effects of storm waves are evaluated through the real time monitoring of groundwater and soil parameters, in order to characterize both the saturated and unsaturated portions of the coastal aquifer of Ravenna and Ferrara (southern Po Delta, Italy). Results highlight a general increase in hydraulic head and soil moisture, along with a decrease in groundwater salinity and pore water salinity due to rainfall infiltration during the 2 days storm event. The only exceptions are represented by the observation wells in proximity to the coastline (within 100 m), which recorded a temporary increase in soil and water salinity caused by the exceptional high waves, which persist on top of the dune crest during the storm event. This generates a saline plume that infiltrates through the vadose zone down to the saturated portion of the aquifer causing a temporary disappearance of the freshwater lens generally present, although limited in size, below the coastal dunes. Despite the high hydraulic conductivity, the aquifer system does not quickly recover the pre‐storm equilibrium and the storm effects are evident in groundwater and soil parameters after 10 days past the storm overwash recess. 相似文献
999.
Zoltán Makó Ferenc Szenkovits Júlia Salamon Robert Oláh-Gál 《Celestial Mechanics and Dynamical Astronomy》2010,108(4):357-370
This paper provides a study of the stable and unstable regions around the smaller primary in the framework of the spatial
elliptic restricted three-body problem. The definitions and methods used to determine stable and unstable regions are extended
to three dimensions. New results concerning the stable and unstable regions around Mercury are obtained in the Sun–Mercury
system. 相似文献
1000.
Gaëlle SAUNIER Franck POITRASSON Bertrand MOINE Michel GREGOIRE Abdelmadjid SEDDIKI 《Meteoritics & planetary science》2010,45(2):195-209
Abstract– Although iron isotopes are increasingly used for meteorites studies, no attempt has been made to evaluate the effect of terrestrial weathering on this isotopic tracer. We have thus conducted a petrographic, chemical, and iron isotopic study of equilibrated ordinary chondrites (OC) recovered from hot Moroccan and Algerian Saharan deserts environment. As previously noticed, we observe that terrestrial desertic weathering is characterized by the oxidation of Fe‐Ni metal (Fe0), sulfide and Fe2+ occurring in olivine and pyroxene. It produces Fe‐oxides and oxyhydroxides that partially replace metal, sulfide grains and also fill fractures. The bulk chemical compositions of the ordinary chondrites studied show a strong Sr and Ba enrichment and a S depletion during weathering. Bulk meteoritic iron isotope compositions are well correlated with the degree of weathering and S, Sr, and Ba contents. Most weathered chondrites display the heaviest isotopic composition, by up to 0.1‰, which is of similar magnitude to the isotopic variations resulting from meteorite parent bodies’ formation and evolution. This is probably due to the release of isotopically light Fe2+ to waters on the Earth’s surface. Hence, when subtle Fe isotopic effects have to be studied in chondrites, meteorites with weathering grade above W2 should be avoided. 相似文献