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Olivier Rossier Emmanuel Castella Jean-Bernard Lachavanne 《Aquatic Sciences - Research Across Boundaries》1996,58(1):1-14
The abundance of different size classes of perch and roach in the littoral zone of Lake Geneva was compared between submerged aquatic vegetation and unvegetated zones. Samples were taken with gillnets during four periods between June and October 1993. During the vegetation period (June to September), perch 9 cm and roach 10 cm were more abundant in vegetation whereas roach > 20 cm were more abundant in open water. Perch larger than 18 cm and medium roach were equally distributed in both habitats whatever the period, whereas medium perch distribution fluctuated according to the period. In October, after the decline of the vegetation, no more differences in fish distribution were observed except for small roach, which were always more abundant in the vegetated sites. 相似文献
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Adrian A. Borsa Jean-Bernard Minster Bruce G. Bills Helen A. Fricker 《Journal of Geodesy》2007,81(2):157-170
We develop and test an algorithm for modeling and removing elevation error in kinematic GPS trajectories in the context of
a kinematic GPS survey of the salar de Uyuni, Bolivia. Noise in the kinematic trajectory ranges over 15 cm and is highly autocorrelated,
resulting in significant contamination of the topographic signal. We solve for a noise model using crossover differences at
trajectory intersections as constraints in a least-squares inversion. Validation of the model using multiple realizations
of synthetic/simulated noise shows an average decrease in root-mean-square-error (RMSE) by a factor of four. Applying the
model to data from the salar de Uyuni survey, we find that crossover differences drop by a factor of eight (from an RMSE of
5.6 to 0.7 cm), and previously obscured topographic features are revealed in a plan view of the corrected trajectory. We
believe that this algorithm can be successfully adapted to other survey methods that employ kinematic GPS for positioning. 相似文献
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Omar Elahcene Abdelali Terfous Boualem Remini Abdellah Ghenaim Jean-Bernard Poulet 《水文科学杂志》2013,58(1):224-236
Abstract Suspended sediment dynamics influenced by rainstorms and factors controlling changes in suspended sediment concentrations, were investigated during hydrological events in a small scale, since small agricultural drainage basins can be considered as one of the most important sediment sources. Suspended sediment concentrations were measured during discharge waves in the years 1987–1990, 1992, 2000 and 2001. Positive and anti-clockwise hysteresis was observed at Rybárik basin. A procedure of isolating factors controlling suspended sediment concentrations and dynamics has given a more realistic view on production and transport of suspended sediment. It is confirmed that spatial and temporal variability of sediment availability and suspended sediment dilution by the baseflow, mainly in the case of two or more waves immediately following one after another, significantly control suspended sediment concentrations and dynamics. 相似文献
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Raphaëlle Juge Brigitte Lods-Crozet Anne Noetzlin Jean Perfetta Jean-Bernard Lachavanne 《Aquatic Sciences - Research Across Boundaries》1985,47(1):64-75
The study of the qualitative and quantitative distribution of the Baldeggersee macrophytic vegetation is undertaken in 1980
with the help of colour aerial photographies and verification on the field. The comparison with old data allows then a short
survey of the macrophytic evolution in relation to the eutrophication.
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Par Gérard Brugermeister Dr Jean-Bernard Lachavanne 《Aquatic Sciences - Research Across Boundaries》1984,46(1):117-138
The qualitative and quantitative distribution of macrophytic vegetation of Greifensee, one of the most eutrophic lakes of
Switzerland, was studied with the help of colour aerial photographs and verifications on the field. This distribution is discussed
in relation to the trophic level of the lake and compared with that of several other Swiss lakes.
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Zuzana Kratinová Karel Schulmann Jean-Bernard Edel Anne-Sophie Tabaud 《International Journal of Earth Sciences》2012,101(3):803-817
Orogenic compression-related fabrics (~340–335 Ma) were reworked during regional extensional deformation (~328–325 Ma) in
a large anatectic crustal domain of the Central Vosges (NE France). The extension was first accommodated by brittle dilation
affecting vertically anisotropic high-grade rocks associated with emplacement of subvertical granitic sheets. The AMS fabric
of granitoids is consistent with highly partitioned transtensional deformation marked by alternations of flat and steep foliations
and development of orthogonal lineations. This deformation passes to top-to-the-southwest ductile shearing expressed in southerly
migmatitic middle crust. The AMS fabric revealed moderately west-dipping foliations bearing subhorizontal NNW–SSE-trending
lineations and predominantly plane strain to prolate shapes. This fabric pattern is interpreted as a viscous response of stretched
partially molten crust during continuous ductile extension. Vertical ascent of voluminous granites and stoping of the upper
crust occurs further south. This gravity ascent triggered by extension leads to development of south-dipping AMS foliations,
south-plunging lineations and oblate fabrics in various crustal granites. Vertical shortening related to ascent of these (~325 Ma)
granitoids and persistent N–S stretching is responsible for reworking and remelting of originally vertical compression-related
fabric in roof supracrustal granites (~340 Ma) and development of highly prolate fabrics in these rocks. This work shows that
the finite shape of AMS fabric ellipsoid is highly sensitive to both strain regime and superpositions of orthogonal deformation
events. 相似文献
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Karel Schulmann Jiří Konopásek Vojtĕch Janoušek Ondrej Lexa Jean-Marc Lardeaux Jean-Bernard Edel Pavla Štípská Stanislav Ulrich 《Comptes Rendus Geoscience》2009,341(2-3):266-286
The geological inventory of the Variscan Bohemian Massif can be summarized as a result of Early Devonian subduction of the Saxothuringian ocean of unknown size underneath the eastern continental plate represented by the present-day Teplá-Barrandian and Moldanubian domains. During mid-Devonian, the Saxothuringian passive margin sequences and relics of Ordovician oceanic crust have been obducted over the Saxothuringian basement in conjunction with extrusion of the Teplá-Barrandian middle crust along the so-called Teplá suture zone. This event was connected with the development of the magmatic arc further east, together with a fore-arc basin on the Teplá-Barrandian crust. The back-arc region – the future Moldanubian zone – was affected by lithospheric thinning which marginally affected also the eastern Brunia continental crust. The subduction stage was followed by a collisional event caused by the arrival of the Saxothuringian continental crust that was associated with crustal thickening and the development of the orogenic root system in the magmatic arc and back-arc region of the orogen. The thickening was associated with depression of the Moho and the flux of the Saxothuringian felsic crust into the root area. Originally subhorizontal anisotropy in the root zone was subsequently folded by crustal-scale cusp folds in front of the Brunia backstop. During the Visean, the Brunia continent indented the thickened crustal root, resulting in the root's massive shortening causing vertical extrusion of the orogenic lower crust, which changed to a horizontal viscous channel flow of extruded lower crustal material in the mid- to supra-crustal levels. Hot orogenic lower crustal rocks were extruded: (1) in a narrow channel parallel to the former Teplá suture surface; (2) in the central part of the root zone in the form of large scale antiformal structure; and (3) in form of hot fold nappe over the Brunia promontory, where it produced Barrovian metamorphism and subsequent imbrications of its upper part. The extruded deeper parts of the orogenic root reached the surface, which soon thereafter resulted in the sedimentation of lower-crustal rocks pebbles in the thick foreland Culm basin on the stable part of the Brunia continent. Finally, during the Westfalian, the foreland Culm wedge was involved into imbricated nappe stack together with basement and orogenic channel flow nappes. 相似文献