Âges et modalités de la mise en place de la couverture limoneuse de la basse plaine de la Garonne d’après l’exemple du site de Fontréal (Castelnau-d’Estrétefonds, Haute Garonne)

Les opérations d’archéologie préventive menées sur la basse plaine de la Garonne, à sa confluence avec les vallées de l’Hers et du Girou, ont permis de réaliser une série d’observations concernant l’origine de la couverture limoneuse. Ainsi, sa mise en place a pu être précisée par l’appoint de données stratigraphiques et sédimentologiques, couplées aux informations paléoenvironnementales et archéologiques. Cette couverture limoneuse, clairement polygénique, moule les irrégularités du toit du corps alluvial de la basse plaine. Elle débute par des limons d’inondation qui nappent les reliefs sablo-graveleux. Une abondante malacofaune y est préservée et a fourni des éléments convergents pour situer leur accumulation à la fin du Pléniglaciaire supérieur. Dans les points bas de la topographie, cette formation a ensuite été recouverte par des limons argileux hydromorphes qui correspondent au colmatage de bas-fonds palustres. Leur accumulation est pro parte synchrone de l’occupation néolithique du site de Fontréal et comprend, à sa base, du matériel archéologique épars ainsi que quelques foyers lenticulaires en place. La répartition des vestiges néolithiques montre, en outre, que la topographie de ce secteur était encore nettement différenciée il y a 4 000 à 5 000 ans et que les secteurs en relief ont été préférentiellement occupés. Le reste du colmatage est nettement plus récent et l’on retrouve, parfois sur plus de deux mètres d’épaisseur, des fragments de briques et de mortier roulés. Leur présence permet de rattacher cette importante sédimentation à l’époque moderne et découle de l’impact des déboisements massifs et de la mise en culture du versant molassique qui domine le site. Sur la basse plaine, les activités agricoles ont finalement achevé son nivellement complet et lui ont donné l’aspect uniformément plan que l’on observe aujourd’hui.Preventive archaeological researches on the lower plain of the Garonne river, around the confluence with the Hers and Girou valleys, allow us to do new observations about the origin of the loam cover. Its origin has been made clearer by the stratigraphic and sedimentological studies, coupled with palaeoenvironnemental and archaeological data. This loam cover, clearly polygenic, blankets the coarse-grained alluvial body of the lower plain. It begins with loams flood deposits which cover the sandy and gravely units. A rich malacofauna was discovered and supplied convergent elements to place their accumulation at the end of the Upper Pleniglacial. In the low-lying areas of the topography, this cover was then covered by clayey silt which corresponds to the filling of paludal depressions. Their accumulation is partially synchronous with the Neolithic occupation of the Fontréal site and includes, at its base, in situ archaeological remains. The distribution of Neolithic remains shows that the topography of this area was still clearly differentiated 4000 - 5000 years ago and that the highest places were preferentially occupied. The rest of the filling, which can be more than two meters thick, is more recent and yielded abundant fragments of bricks and rolled mortar. Their presence allows us to link this important sedimentary phase with the modern period. This should be the consequence of massive deforestations on the sandy-clay hillside that dominates the site. Agricultural activities finished the complete levelling of the lower plain and gave it the uniformly flat aspect that one can see today

Practice makes the model: a critical review of stormwater green infrastructure modelling practice

Green infrastructures (GIs) have in recent decades emerged as sustainable technologies for urban stormwater management, and numerous studies have been conducted to develop and improve hydrological models for GIs. This review aims to assess current practice in GI hydrological modelling, encompassing the selection of model structure, equations, model parametrization and testing, uncertainty analysis, sensitivity analysis, the selection of objective functions for model calibration, and the interpretation of modelling results. During a quantitative and qualitative analysis, based on a paper analysis methodology applied across a sample of 270 published studies, we found that the authors of GI modelling studies generally fail to justify their modelling choices and their alignments between modelling objectives and methods. Some practices, such as uncertainty analysis, were also found to be limited, despite their necessity being widely acknowledged by the scientific community and their application in other fields. In order to improve current GI modelling practice, the authors suggest the following: i) a framework, called STAMP, designed to promote the standardisation of the documentation of GI modelling studies, and ii) improvements in modelling tools for facilitating good practices, iii) the sharing of data for better model testing, iv) the evaluation of the suitability of hydrological equations for GI application, v) the publication of clear statements regarding model limitations and negative results.publishedVersio

Batch kernel SOM and related Laplacian methods for social network analysis

Large graphs are natural mathematical models for describing the structure of the data in a wide variety of fields, such as web mining, social networks, information retrieval, biological networks, etc. For all these applications, automatic tools are required to get a synthetic view of the graph and to reach a good understanding of the underlying problem. In particular, discovering groups of tightly connected vertices and understanding the relations between those groups is very important in practice. This paper shows how a kernel version of the batch Self Organizing Map can be used to achieve these goals via kernels derived from the Laplacian matrix of the graph, especially when it is used in conjunction with more classical methods based on the spectral analysis of the graph. The proposed method is used to explore the structure of a medieval social network modeled through a weighted graph that has been directly built from a large corpus of agrarian contracts

MENTOR ou une méthodologie et des outils opérationnels de conception et de qualification de sites de mesures en réseau d'assainissement

International audienceLe projet MENTOR (MEasurement sites conception method for sewer NeTwORks) a pour objectif principal d'aider les gestionnaires dans la mise en place d'une instrumentation intégrée de la chaîne de mesures visant à mieux surveiller en continu la quantité et la qualité des masses d'eau rejetées par les systèmes urbains d'assainissement. Ce projet permettra la mise au point d'outils opérationnels destinés aux gestionnaires et aux responsables de métrologie des réseaux d'assainissement urbains. Il fournira également des recommandations au niveau organisationnel qui aideront à l'acquisition de " bonnes pratiques métrologiques ". Nous présenterons le détail de la démarche puis nous illustrerons cela par quelques cas concrets traités par les partenaires du projet

New stable QTLs for berry weight do not colocalize with QTLs for seed traits in cultivated grapevine (Vitis vinifera L.)

International audienceBACKGROUND: In grapevine, as in other fruit crops, fruit size and seed content are key components of yield and quality; however, very few Quantitative Trait Loci (QTLs) for berry weight and seed content (number, weight, and dry matter percentage) have been discovered so far. To identify new stable QTLs for marker-assisted selection and candidate gene identification, we performed simultaneous QTL detection in four mapping populations (seeded or seedless) with various genetic backgrounds. RESULTS: For berry weight, we identified five new QTLs, on linkage groups (LGs) 1, 8, 11, 17 and 18, in addition to the known major QTL on LG 18. The QTL with the largest effect explained up to 31% of total variance and was found in two genetically distant populations on LG 17, where it colocalized with a published putative domestication locus. For seed traits, besides the major QTLs on LG 18 previously reported, we found four new QTLs explaining up to 51% of total variance, on LGs 4, 5, 12 and 14. The previously published QTL for seed number on LG 2 was found related in fact to sex. We found colocalizations between seed and berry weight QTLs only for the major QTL on LG 18 in a seedless background, and on LGs 1 and 13 in a seeded background. Candidate genes belonging to the cell number regulator CNR or cytochrome P450 families were found under the berry weight QTLs on LGs 1, 8, and 17. The involvement of these gene families in fruit weight was first described in tomato using a QTL-cloning approach. Several other interesting candidate genes related to cell wall modifications, water import, auxin and ethylene signalling, transcription control, or organ identity were also found under berry weight QTLs. CONCLUSION: We discovered a total of nine new QTLs for berry weight or seed traits in grapevine, thereby increasing more than twofold the number of reliable QTLs for these traits available for marker assisted selection or candidate gene studies. The lack of colocalization between berry and seed QTLs suggests that these traits may be partly dissociated

Pancreatic cancer intrinsic PI3Kα activity accelerates metastasis and rewires macrophage component.

Pancreatic ductal adenocarcinoma (PDAC) patients frequently suffer from undetected micro-metastatic disease. This clinical situation would greatly benefit from additional investigation. Therefore, we set out to identify key signalling events that drive metastatic evolution from the pancreas. We searched for a gene signature that discriminate localised PDAC from confirmed metastatic PDAC and devised a preclinical protocol using circulating cell-free DNA (cfDNA) as an early biomarker of micro-metastatic disease to validate the identification of key signalling events. An unbiased approach identified, amongst actionable markers of disease progression, the PI3K pathway and a distinctive PI3Kα activation signature as predictive of PDAC aggressiveness and prognosis. Pharmacological or tumour-restricted genetic PI3Kα-selective inhibition prevented macro-metastatic evolution by hindering tumoural cell migratory behaviour independently of genetic alterations. We found that PI3Kα inhibition altered the quantity and the species composition of the produced lipid second messenger PIP3 , with a selective decrease of C36:2 PI-3,4,5-P3 . Tumoural PI3Kα inactivation prevented the accumulation of pro-tumoural CD206-positive macrophages in the tumour-adjacent tissue. Tumour cell-intrinsic PI3Kα promotes pro-metastatic features that could be pharmacologically targeted to delay macro-metastatic evolution