La terminaison des nerfs pneumo-gastriques chez l'homme et les singes anthropomorphes

Clavelin P., Coulouma . La terminaison des nerfs pneumo-gastriques chez l'homme et les singes anthropomorphes. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, VIII° Série. Tome 5, 1934. pp. 51-59

Regional predictions of eight commonsoil properties and their spatial structures from hyperspectral Vis-NIR data

International audienceThe potential of the visible-near infrared (Vis-NIR; 400-2500 nm) laboratory spectroscopy for the estimation of soil properties has been previously demonstrated in the literature, and the Vis-NIR spatial spectroscopy is expected to provide direct estimates of these properties at the soil surface. The aim of this work was to examine whether Vis-NIR airborne spectroscopy could be used for mapping eight of the most common soil properties, including clay, sand, silt, calcium carbonate (CaCO3), free iron, cation-exchange capacity (CEC), organic carbon and pH, without mispredicting the local values of these properties and their spatial structures. Our study was based on 95 soil samples and a HyMap hyperspectral image available over 192 bare soil fields scattered within a 24.6 km(2) area. Predictions of soil properties from HyMap spectra were computed for the eight soil properties using partial least squares regression (PLSR). The results showed that 1) four out of the eight soil properties (CaCO3, iron, clay and CEC) were suitable for mapping using hyperspectral data, and both accurate local predictions and good representations of spatial structures were observed and 2) the application of prediction models using hyperspectral data over the study area provided statistical characterizations within soilscape variations and variograms that describe in details the short range soil variations. All results were consistent with the previous pedological knowledge of the studied region. This study opens up the possibility of more extensive use of hyperspectral data for digital soil mapping of these successfully predicted soil properties

Spatial variability of soil compaction over a vineyard region in relation with soils and cultivation operations

International audienceIn the vineyard Languedoc plain soil compaction caused by tillage operations and traffic is suspected to have a long-term effect on vineyard production. To assess the importance of this soil compaction at the scale of a vine production area and to determine its various origins, a field method based on the morphological observation of the soil structure was applied at 28 sites that cover the variability of soils and vineyard operations within the Languedoc plain. Zones with a very high degree of compactness (A zones) were delineated in soil profiles and the origins of these zones were partly identified thanks to a set of rules considering the location of the A zones in the soil profile. The areas of Delta zones were summed at the site and at the regional scale to provide quantified indicators of soil compaction. The proposed method proved to be effective in assessing soil compaction at a regional scale, the delineated Delta zones exhibiting significant increases of bulk density. The results showed i) generally moderate levels of soil compaction with a few heavily compacted sites, ii) the equal predominance of compactions due to deep ploughing and traffic of tractors and their trailed tools, iii) the increase of soil compaction by deep ploughing in redoxisols in which wet conditions are more frequent, iv) the decrease of soil compaction by surface vineyard operations (tractor traffic, superficial tillage, harvesting) in case of grassed vine interrows

Combining Vis-NIR hyperspectral imagery and legacy measured soil profiles to map subsurface soil properties in a Mediterranean area (Cap-Bon, Tunisia)

International audiencePrevious studies have demonstrated that Visible Near InfraRed (Vis-NIR) hyperspectral imagery is a cost-efficient way to map soil properties at fine resolutions (similar to 5 m) over large areas. However, such mapping is only feasible for the soil surface because the effective penetration depths of optical sensors do not exceed several millimeters. This study aims to determine how Vis-NIR hyperspectral imagery can serve to map the subsurface properties at four depth intervals (15-30 cm, 30-60 cm, 60-100 cm and 30-100 cm) when used with legacy soil profiles and images of parameters derived from digital elevation model (DEM). Two types of surface-subsurface functions, namely linear models and random forests, that estimate subsurface property values from surface values and landscape covariates were first calibrated over the set of legacy measured profiles. These functions were then applied to map the soil properties using the hyperspectral-derived digital surface soil property maps and the images of landscape covariates as input. Error propagation was addressed using a Monte Carlo approach to estimate the mapping uncertainties. The study was conducted in a pedologically contrasted 300 km(2)-cultivated area located in the Cap Bon region (Northern Tunisia) and tested on three soil surface properties (clay and sand contents and cation exchange capacity). The main results were as follows: i) fairly satisfactory (cross-validation R-2 between 0.55 and 0.81) surface-subsurface functions were obtained for predicting the soil properties at 15-30 cm and 30-60 cm, whereas predictions at 60-100 cm were less accurate (R-2 between 0.38 and 0.43); ii) linear models outperformed random-forest models in developing surface-subsurface functions; iii) due to the error propagations, the final predicted maps of the subsurface soil properties captured from 1/3 to 2/3 of the total variance with a significantly decreasing performance with depth; and iv) these maps brought significant improvements over the existing soil maps of the region and showed soil patterns that largely agreed with the local pedological knowledge. This paper demonstrates the added value of combining modern remote sensing techniques with old legacy soil databases. (C) 2013 Elsevier B.V. All rights reserved

Synchronous t-Resilient Consensus in Arbitrary Graphs

Best Paper AwardInternational audienceWe study the number of rounds needed to solve consensus in a synchronous network G where at most t nodes may fail by crashing. This problem has been thoroughly studied when G is a complete graph, but very little is known when G is arbitrary. We define a notion of radius that considers all ways in which t nodes may crash, and present an algorithm that solves consensus in radius rounds. Then we derive a lower bound showing that our algorithm is optimal for vertex-transitive graphs, among oblivious algorithms

Model-based evaluation of irrigation needs in Mediterranean vineyards

The irregular rainfall distribution causes interannual variation of water status in Mediterranean vineyards. A frequential analysis of irrigation needs was carried out from continuous simulation of the soil water balance during 39 years in south France. The off-season soil water refilling was often incomplete, with a higher frequency in soils with a high total transpirable soil water (TTSW) and/or susceptible to runoff and high evaporation. On soils with high TTSW (over 250 mm), the irrigation need was nil or small (except in situations of high runoff) and focused on the beginning of the crop cycle. On soils with lower TTSW, the irrigation need increased on average and was spread all along the grapevine cycle due to the limited buffering effect of the soil water reservoir. For 100 mm TTSW, the irrigation need was 40-60 mm for half of the years. The calculated irrigation needs were sensitive to the soil (TTSW, susceptibility to runoff and evaporation) and canopy (crop coefficient) properties. Therefore, soil and canopy management should be considered together with irrigation for an integrated approach of water management