Stability monitoring of high Alpine infrastructure by terrestrial laser scanning

International audienceRock mass movements are dominant in the morphodynamics of high Alpine rock slopes and are at the origin of significant risks for people who attend these areas and for infrastructures that are built on (e.g. huts, cable cars). These risks are increasing because of permafrost degradation and glacier retreat as consequences of the global warming. These two factors may affect slope stability by changing mechanical properties of the interstitial ice and modifying the mechanical constraints in these rock slopes. The monitoring of rock slopes is thus an essential element for risk management. Our study focuses on two particularly active areas of the Western Alps: the lower Arête des Cosmiques (3613 m a.s.l., Mont Blanc massif, France) on which is located the very popular Refuge des Cosmiques, and the Col des Gentianes (2894 m a.s.l., Valais, Switzerland) where is located a cable car station. Discussed on the basis of geophysical and glaciological data, the evolutions monitored by terrestrial laser scanning probably result from the combination between permafrost activity/degradation and glacier shrinkage

PP2A-B’γ modulates foliar trans-methylation capacity and the formation of 4-methoxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves

Glucosinolates (GSL) of cruciferous plants comprise a major group of structurally diverse secondary compounds which act as deterrents against aphids and microbial pathogens and have large commercial and ecological impacts. While the transcriptional regulation governing the biosynthesis and modification of GSL is now relatively well understood, post-translational regulatory components that specifically determine the structural variation of indole glucosinolates have not been reported. We show that the cytoplasmic protein phosphatase 2A regulatory subunit B'gamma (PP2A-B'gamma) physically interacts with indole glucosinolate methyltransferases and controls the methoxylation of indole glucosinolates and the formation of 4-meth-oxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves. By taking advantage of proteomic approaches and metabolic analysis we further demonstrate that PP2A-B'gamma is required to control the abundance of oligomeric protein complexes functionally linked with the activated methyl cycle and the trans-methylation capacity of leaf cells. These findings highlight the key regulatory role of PP2A-B'gamma in methionine metabolism and provide a previously unrecognized perspective for metabolic engineering of glucosinolate metabolism in cruciferous plants.Peer reviewe

Labour supply and employment in the euro area countries - developments and challenges

The aim of this report, which has been prepared by a Task Force of the Monetary Policy Committee of the Eurosystem, is to describe and analyse the main developments in labour supply and its determinants in the euro area, review the links between labour supply and labour market institutions, assess how well labour supply reflects the demand for labour in the euro area and identify the future challenges for policy-makers. The data available for this report generally cover the period from 1983 to spring 2007. JEL Classification: E5, J1, J2, J6.Labour supply, employment, participation, hours worked, immigration, skill and education, structural policies, labour demand, unemployment, euro area countries, labour markets, taxes and benefits, childcare, pensions, training, human capital, labour quality, working time and contracts, discrimination, mismatch, returns to education.

Folate polyglutamylation is required for rice seed development

In plants, polyglutamylated folate forms account for a significant proportion of the total folate pool. Polyglutamylated folate forms are produced by the enzyme folylpolyglutamate synthetase (FPGS). The FPGS enzyme is encoded by two genes in rice, Os03g02030 and Os10g35940. Os03g02030 represents the major expressed form in developing seed. To determine the function of this FPGS gene in rice, a T-DNA knockout line was characterised. Disrupting Os03g02030 gene expression resulted in delayed seed filling. LC-MS/MS-based metabolite profiling revealed that the abundance of mono- and polyglutamylated folate forms was significantly decreased in seeds of the knockout line. RT-qPCR detected an increase in the transcript abundance of folate biosynthesis genes in seed of the knockout plant, whereas the folate deglutamating enzyme ?-glutamyl hydrolase mRNA level was reduced. Our study has uncovered a novel role for folate polyglutamylation during rice seed development and a potential feedback mechanism to maintain folate abundance.(Résumé d'auteur

Using Terrestrial Laser Scanning for the Recognition and Promotion of High-Alpine Geomorphosites

International audienceHigh-alpine geomorphosites are poorly understood and developed, mostly because of the heavy constraints of high mountain areas. Meanwhile, they are geoheritage areas that are often extremely vulnerable to global warming: glaciers and permafrost areas are currently affected by major changes due to increasing air temperature. To deal with the high spatial variability of landforms and processes, research on alpine geomorphosites often needs the use of advanced methods of high-resolution topography, among which terrestrial laser scanning plays an increasingly crucial role. Carried out on some tenth of high-elevation sites across the Alps since the beginning of the 2000s, this method is particularly interesting for the recognition and development of high-alpine geomorphosites. Indeed, it can be implemented for identifying and characterizing the geomorphic objects (survey, monitoring and mapping), helping planning and protection policies and serving geotouristic development (communication about the processes involved, basis for documents)

Effects of climate change on high Alpine mountain environments: Evolution of mountaineering routes in the Mont Blanc massif (Western Alps) over half a century

International audienceIn high alpine environments, glacial shrinkage and permafrost warming due to climate change have significant consequences on mountaineering routes. Few research projects have studied the relationship between climate change and mountaineering; this study attempts to characterize and explain the evolution over the past 40 years of the routes described in The Mont Blanc Massif: The 100 Finest Routes, Gaston Rébuffat's emblematic guidebook, published in 1973.The main elements studied were the geomorphic and cryospheric changes at work and their impacts on the itinerary's climbing parameters, determining the manner and possibility for an itinerary to be climbed. Thirty-one interviews, and comparison with other guidebooks, led to the identification of 25 geomorphic and cryospheric changes related to climate change that are affecting mountaineering itineraries. On average, an itinerary has been affected by nine changes. Among the 95 itineraries studied, 93 have been affected by the effects of climate change-26 of them have been greatly affected; and three no longer exist. Moreover, periods during which these itineraries can be climbed in good conditions in summer have tended to become less predictable and periods of optimal conditions have shifted toward spring and fall, because the itineraries have become more dangerous and technically more challenging

Labour supply and employment in the euro area countries - developments and challenges

The aim of this report, which has been prepared by a Task Force of the Monetary Policy Committee of the Eurosystem, is to describe and analyse the main developments in labour supply and its determinants in the euro area, review the links between labour supply and labour market institutions, assess how well labour supply reflects the demand for labour in the euro area and identify the future challenges for policy-makers. The data available for this report generally cover the period from 1983 to spring 2007

Investigation of a cold-based ice apron on a high-mountain permafrost rock wall using ice texture analysis and micro-14C dating : a case study of the Triangle du Tacul ice apron (Mont Blanc massif, France)

This study is part of the ANR 14-CE03-0006 VIP Mont Blanc and the EU ALCOTRA AdaPT Mont Blanc project.The current paper studies the dynamics and age of the Triangle du Tacul (TDT) ice apron, a massive ice volume lying on a steep high-mountain rock wall in the French side of the Mont-Blanc massif at an altitude close to 3640 m a.s.l. Three 60 cm long ice cores were drilled to bedrock (i.e. the rock wall) in 2018 and 2019 at the TDT ice apron. Texture (microstructure and lattice-preferred orientation, LPO) analyses were performed on one core. The two remaining cores were used for radiocarbon dating of the particulate organic carbon fraction (three samples in total). Microstructure and LPO do not substantially vary with along the axis of the ice core. Throughout the core, irregularly shaped grains, associated with strain-induced grain boundary migration and strong single maximum LPO, were observed. Measurements indicate that at the TDT ice deforms under a low strain-rate simple shear regime, with a shear plane parallel to the surface slope of the ice apron. Dynamic recrystallization stands out as the major mechanism for grain growth. Micro-radiocarbon dating indicates that the TDT ice becomes older with depth perpendicular to the ice surface. We observed ice ages older than 600 year BP and at the base of the lowest 30 cm older than 3000 years.Publisher PDFPeer reviewe

Ergothioneine Biosynthesis and Functionality in the Opportunistic Fungal Pathogen, Aspergillus fumigatus.

Ergothioneine (EGT; 2-mercaptohistidine trimethylbetaine) is a trimethylated and sulphurised histidine derivative which exhibits antioxidant properties. Here we report that deletion of Aspergillus fumigatus egtA (AFUA_2G15650), which encodes a trimodular enzyme, abrogated EGT biosynthesis in this opportunistic pathogen. EGT biosynthetic deficiency in A. fumigatus significantly reduced resistance to elevated H2O2 and menadione, respectively, impaired gliotoxin production and resulted in attenuated conidiation. Quantitative proteomic analysis revealed substantial proteomic remodelling in ΔegtA compared to wild-type under both basal and ROS conditions, whereby the abundance of 290 proteins was altered. Specifically, the reciprocal differential abundance of cystathionine γ-synthase and β-lyase, respectively, influenced cystathionine availability to effect EGT biosynthesis. A combined deficiency in EGT biosynthesis and the oxidative stress response regulator Yap1, which led to extreme oxidative stress susceptibility, decreased resistance to heavy metals and production of the extracellular siderophore triacetylfusarinine C and increased accumulation of the intracellular siderophore ferricrocin. EGT dissipated H2O2 in vitro, and elevated intracellular GSH levels accompanied abrogation of EGT biosynthesis. EGT deficiency only decreased resistance to high H2O2 levels which suggests functionality as an auxiliary antioxidant, required for growth at elevated oxidative stress conditions. Combined, these data reveal new interactions between cellular redox homeostasis, secondary metabolism and metal ion homeostasis

Neige et Glace de Montagne : Reconstitution, dynamique, pratiques

Collection edytem n°8International audienceLes cahiers (de géographie, géologie et paléoenvironnement) de la Collection EDYTEM visent à faire connaître les recherches menées au sein du laboratoire EDYTEM ou de programmes dans lequel nous sommes impliqués. Si la priorité est la diffusion de nos travaux dans les revues majeures de nos communautés et les congrès internationaux, il nous paraît également important de mettre en avant la transversalité des recherches du laboratoire qui mobilise plusieurs champs disciplinaires autour de mêmes objets d'étude. Il est, en effet, difficile de mettre en avant cette dimension par le seul biais des publications dans des revues ou des communications qui répondent avant tout à des logiques disciplinaires. La Collection EDYTEM a cette mission : rendre visible la démarche interdisciplinaire du laboratoire autour d'entrées fédératrices : les systèmes hydrothermaux de montagne, les systèmes nivo-glaciaires et les systèmes karstiques. Trois entrées qui caractérisent les objets privilégiés d'étude du laboratoire. Après le numéro dédié à l'Aven d'Orgnac porté par " l'axe karst ", ce nouveau numéro illustre les recherches menées sur la haute montagne et les systèmes nivo-glaciaires. Le prochain numéro également prévu en 2009 traitera de l'hydrothermalisme de montagne. Soulignons que ces trois axes ont été mis en place il y a un peu plus de deux ans. Le fait que chacun d'entre eux produise en peu de temps des synthèses originales, reflète la rapide mobilisation des différents champs disciplinaires du laboratoire sur ces objets de recherche. Ce numéro " Neige et glace " illustre parfaitement cette dynamique. La participation très active des doctorants, comme contributeurs mais aussi animateurs des réunions de travail et de chantiers de recherche en est un bon exemple. Tout comme la structuration du numéro, qui aborde les reconstitutions paléoenvironnementales (de la dernière grande glaciation au Petit Âge Glaciaire), les dynamiques actuelles, à la fois reflets et indicateurs du changement climatique, et les incidences de ce changement sur le tourisme hivernal, les risques en montagne. Ces trois entrées illustrent les apports respectifs des trois équipes du laboratoire. Les 21 contributions originales de ce cahier reflètent la dynamique du laboratoire sur la montagne et les priorités mises à la fois sur les outils (laserscanning, métrologie, dendrochronologie, photogrammétrie, imagerie, modélisation...), les recherches doctorales (T. Barth, N. Cayla, S. Coutterand, P. Paccard, L. Ravanel et M. Le Roy) et l'accueil de chercheurs et de post-doct étrangers (S. Gruber, M. Kirkbride). Ce numéro a le mérite de poser clairement les recherches menées par le laboratoire sur la haute montagne, la neige et les glaciers et sa contribution dans les sciences de l'environnement