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Journal of Soils and Sediments - River infrastructures such as dikes, groynes, and dams are ubiquitous on most large rivers, and although their consequences on the riverbed morphology have often...  相似文献   
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  1. Knowledge about spatial and temporal variability in the distribution and abundance of predators is necessary to adapt measures to mitigate human–wildlife interactions.
  2. Acoustic telemetry and network analyses were used to investigate the spatial ecology of bull sharks, the species responsible for most shark bites in Reunion Island, one of the world's shark bite hotspots.
  3. The west coast of the island was not used uniformly by every individual, with size predicting the movements of sharks along the coast.
  4. Node-based metrics – closeness, node strength, and cumulated continuous residency times – derived from up to 181 monthly movement networks from 20 individuals, revealed that smaller sharks (<250 cm total length) primarily used the south-west coast while larger individuals spent most of their time in the northern region with regular visits to multiple areas along the coast.
  5. This study provides essential knowledge on bull shark behaviour and central areas used at different periods of the year, which correlates well with the dynamics of observed shark bites. Our approach provides a non-invasive alternative to help predicting and anticipating human–shark conflicts and avoid shark culling programmes detrimental to the conservation of large predators such as sharks.
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A novel conotoxin (conopeptide) was biochemically characterized from the crude venom of the molluscivorous marine snail, Conus bandanus (Hwass in Bruguière, 1792), collected in the south-central coast of Vietnam. The peptide was identified by screening bromotryptophan from chromatographic fractions of the crude venom. Tandem mass spectrometry techniques were used to detect and localize different post-translational modifications (PTMs) present in the BnIIID conopeptide. The sequence was confirmed by Edman’s degradation and mass spectrometry revealing that the purified BnIIID conopeptide had 15 amino acid residues, with six cysteines at positions 1, 2, 7, 11, 13, and 14, and three PTMs: bromotryptophan, γ-carboxy glutamate, and amidated aspartic acid, at positions “4”, “5”, and “15”, respectively. The BnIIID peptide was synthesized for comparison with the native peptide. Homology comparison with conopeptides having the III-cysteine framework (–CCx1x2x3x4Cx1x2x3Cx1CC–) revealed that BnIIID belongs to the M-1 family of conotoxins. This is the first report of a member of the M-superfamily containing bromotryptophan as PTM.  相似文献   
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While much research has been done on predicting the occurrence of waterlogged soils in small catchments, we need to improve our knowledge of the extension of these soils in large catchments. The aim of this study is to analyse the extent of soils with redoximorphic features in the valley bottomland domain as a function of the stream order.This study concerns a 10,000 km2 catchment (River Vilaine, Armorican massif, north-western France) where valley bottomland soils commonly associated with hydromorphic characteristics cover up to 20% of the basin area. To describe the catchment organisation, we used the stream order classification of Strahler to test the behaviour of the topographic index in a large range of landscape morphological settings. Two methods were used to define the extent of the hydromorphic zone (HZ) in each valley bottomland according to stream order: (i) A field study based on mapping the HZ according to the occurrence of redoximorphic features along 60 transects; (ii) a modelling approach linking a DEM-derived topographic index to the digitized stream network of the River Vilaine.In view of the topographic factors, progressive valley widening may represent an enhancing factor of HZ extent. Thus, simple topographic index modelling predicts an increase in waterlogging in high-order channel settings (orders 6–7). By contrast, field mapping suggests that HZ extent remains stable with increasing order and decreases significantly for high-order settings (orders 6–7). Therefore, topographic index modelling appears effective in upper catchment settings (1st, 2nd and 3rd order). On the contrary, modelling efficiency is limited in high-order settings where the indices prove to be inappropriate: in such contexts, interactions between adjacent hillslope and HZ are of secondary importance. Along the longitudinal profile of the catchment, soil material near the streams shifts from having a colluvial origin in low-order to an alluvial origin in high-order settings. In high-order settings, the fine-scale valley bottomland topography and the spatial organisation of deposits control waterlogging duration and possibly play a major role in HZ extent. Finally, the integration of stream order data should considerably improve the efficiency of modelling the spatial distribution of soils over large catchments.  相似文献   
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