排序方式： 共有54条查询结果，搜索用时 15 毫秒
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Jonas V. Müller Christian Berg Jacqueline Détraz-Méroz Brigitta Erschbamer Noémie Fort Catherine Lambelet-Haueter Vera Margreiter Florian Mombrial Andrea Mondoni Konrad Pagitz Francesco Porro Graziano Rossi Patrick Schwager Elinor Breman 《山地科学学报》2017,14(4):806-810
Safeguarding plants as seeds in ex situ collections is a cost effective element in an integrated plant conservation approach. The European Alps are a regional centre of plant diversity. Six institutions have established a regional network covering the European Alps which will conserve at least 500 priority plant species and which will improve the conservation status of plant species in grassland communities in the subalpine, alpine and nival altitudinal belts. Targeted research will expand the knowledge of the ecology of target species. Public engagement activities will raise the awareness for the importance of specific conservation actions in the European Alps. 相似文献
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This paper presents a static equivalent approach to estimate the maximum kinematic interaction effects on piles subjected to lateral seismic excitation. Closed-form expressions are reported for the evaluation of the maximum free-field soil movements and for the computation of maximum pile shear force and bending moments. Firstly, modal analysis, combined with a suitable damped response spectrum, is used to evaluate the maximum free-field response. Secondly, the pile is schematised as a Winkler's beam subjected to equivalent static forces defined according to soil vibration modal shapes and amplitude. The method may be applied by using response spectra suggested by National Standards or those obtained with accelerograms. The procedure proposed may be conveniently implemented in simple spreadsheets or in commercial finite element programs and easily used by practicing engineers. Method accuracy is demonstrated by comparing the results with those obtained with a more rigorous model. Good results may be achieved by considering only the first soil vibration mode making the procedure straightforward for practical design purposes. 相似文献
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Di Franco A Graziano M Franzitta G Felline S Chemello R Milazzo M 《Marine pollution bulletin》2011,62(5):926-933
Many human activities add new structures to the marine landscape. Despite the fact that human structures cause some inevitable impacts, surprisingly little information exists on the effects of marina on natural marine assemblages. The aim of this paper is to assess habitat-specific response of benthic sessile organisms of rocky shores in relation to the presence of a small marina. Sampling was carried out at three coastal habitats (midshore, lowshore and subtidal) by means of visual censuses adopting an after-control-impact (ACI) experimental design. It appears that the marina affects the structure and composition of benthic communities of both the midshore and the lowshore. Little effect was evident on shallow subtidal assemblage structure. The results of the present study clearly show habitat-specific responses of coastal benthic assemblages to the presence of infrastructure. 相似文献
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A. Argüelles S. A. Khainakov J. Rodríguez-Fernández M. Leoni J. A. Blanco C. Marcos 《Physics and Chemistry of Minerals》2011,38(7):569-580
Herein we report on synthetic iron-intercalated vermiculites prepared from a Mg-vermiculite mineral from Santa Olalla, Huelva, Spain, by means of an ion exchange process from aqueous solutions of FeCl2 and FeCl3. Thermogravimetric, X-ray diffraction, magnetic susceptibility and Mössbauer spectral studies have been used to characterize the synthetic iron-intercalated vermiculites. The results suggest that the intercalation process employed induces modifications in both the interlayer spacing and in the octahedral sheet; the disordered structure of the Mg-vermiculite mineral is not altered. The presence of solvated Fe(H2O) n 2+ ions has been shown by the Mössbauer spectroscopy. No magnetic order has been observed between 2 and 300 K neither in the Mg-vermiculite mineral nor in the two synthetic iron-intercalated vermiculites. 相似文献
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Celia Ojeda-Martínez Francisca Giménez Casalduero Just T. Bayle-Sempere Carmen Barbera Cebrián Carlos Valle Jose Luis Sanchez-Lizaso Aitor Forcada Pablo Sanchez-Jerez Pablo Martín-Sosa Jesús M. Falcón Fuensanta Salas Mariagrazia Graziano Renato Chemello Ben Stobart Pedro Cartagena Angel Pérez-Ruzafa Fréderic Vandeperre Elisabeth Rochel Serge Planes Alberto Brito 《Ocean & Coastal Management》2009,52(2):89-101
A general conceptual framework for the management of marine protected areas (MPAs) was developed. The driver-pressure-state-impacts-response (DPSIR) framework was used to determine the elements affecting MPAs. The developed evaluation framework helped to select an appropriate suite of indicators to support an ecosystem approach, an assessment of the MPAs functioning and policy decisions. Gaps derived from the management and policy responses in the MPAs were also outlined. It was concluded that the DPSIR framework can help to simplify the complexity of MPA management. This document is a tool for policy makers, scientists and general public on the relevance of indicators to monitor changes and MPAs management. 相似文献
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The thermal conductivity (TC) of metal and rock samples was determined, under ambient conditions, using standard X-ray diffraction equipment in which only the diffractometer sample holder had been modified from the original. As the method is comparative, standard reference materials were used: a copper standard for the analysis of metals and marble for the rock specimens. The marble was analyzed beforehand using a quick thermal conductivity meter QTM. In experimental measurements of TC the mean reproducibility value appears to be about 4% while the accuracy is about 5% for the examined rocks, and better for metals. 相似文献
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Alessandro Ellero Leonardo Leoni Michele Marroni Ionel Nicolae Luca Pandolfi Franco Sartori 《Comptes Rendus Geoscience》2002,334(5):347-354
The Fenes Nappe belongs to the stack of tectonic units cropping out in the southern Apuseni Mts (Romania). It is characterised by a structural history consisting of two folding phases that developed during the time spanning from Early Aptian to Late Maastrichtian. The D1 phase produced west-northwest-verging, isoclinal to very tight folds, associated to a slaty cleavage. The main metamorphic imprint of the Fenes Nappe is linked to this deformation phase; illite and chlorite ‘crystallinity’ values indicate metamorphic conditions of the late diagenesis, close to the diagenetic zone/anchizone boundary. The subsequent D2 phase produced north-northwest-verging, parallel folds, not associated with synkinematic recrystallisation. These phases are interpreted as developed during a structural path, which includes burial at a depth of 8–10 km, followed by exhumation at shallower structural levels. To cite this article: A. Ellero et al., C. R. Geoscience 334 (2002) 347–354. 相似文献
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Petrological, mineralogical and chemical data of 46 ejecta deriving from the sedimentary basement beneath Somma-Vesuvius volcano are reported. The ejecta samples were collected in pumice deposits formed during two major Plinian eruptions. One of these pumice deposits was formed during the well-known 79 A.D. eruption, and the other one — the so-called Avellino pumice — during an eruption occurred about 3,500 years B.P. Most of the ejecta from both the layers are fragments of contact-metamorphosed carbonate rocks. For the ejecta of the 79 A.D. Plinian eruption, the mineralogical parageneses of the metamorphosed carbonate rocks (dolomite-Mg calcite-periclase, and dolomite-Mg calcite-brucite) allow the evaluation of the conditions under which contact metamorphism developed. Temperatures, estimated by the Mg content in the calcite coexisting with dolomite, ranged from 360° to 790°C, whereas total fluid pressure would not have exceeded 1,500–2,000 bars with a maximum depth of metamorphism (and hence of the magma chambers) of 5,000–6,000 m. The ejecta from the so-called Avellino pumice layer (characzerized prevalently by a dolomite-Mg calcite assemblage) show that contact metamorphism occurred under the same temperature range as that of the 79 A.D. ejecta, but at an higherP CO2 partial pressure and probably at an higher total fluid pressure. These differences in physico-chemical conditions of metamorphism seem to indicate that the two Plinian eruptions were fed probably by two different magma chambers. Comparison between chemical composition of the carbonate ejecta and carbonate samples of the Mesozoic sedimentary series outcropping near the volcano indicates that fragmentation of almost all the sequence were brought to the surface by the explosive Plinian eruptions. Although the data at our disposal do not provide any information on the size of the 79 A.D. eruption magma chamber, this probably had an important vertical length component of at least 2,000 m 相似文献