Saint Nicolas-de-Bourgueuil – Les caves de la Gardière

Date de l'opération : 1984 (SD) Inventeur(s) : Lecompte Jean-Paul ; Boucher M A la suite du déblaiement d'une cave, un grand nombre de fragments de céramique furent récupérés par le propriétaire. En 1984, un relevé stratigraphique fut réalisé dans une petite partie du remblai qui paraît dater du XVe et du XVIe s

L'innovation, condition de la pérennité des systèmes agroalimentaires localisés

La production agroalimentaire artisanale et les produits de terroir ont bien souvent une image traditionnelle, celle de pratiques figées dans le temps, transmises de génération en génération. L'analyse montre au contraire des systèmes agroalimentaires localisés (Syal) confrontés à des besoins permanents d'innovation, pour faire face à des évolutions internes (réduction de la capacité de coordination et d'action collective) et/ ou externes (nouvelles contraintes ou opportunités techniques ou commerciales). Face à ces besoins, certains systèmes sont à même d'instaurer des interactions accrues entre acteurs locaux et acteurs extra-locaux, débouchant sur des innovations techniques ou organisationnelles. Le concept de Syal permet alors d'éclairer bien mieux ces processus d'innovation collectifs et localisés que ne le font les schémas diffusionnistes, et de mettre aussi en évidence les voies d'appui

Soliton Lattices in the Incommensurate Spin-Peierls Phase: Local Distortions and Magnetizations

It is shown that nonadiabatic fluctuations of the soliton lattice in the spin-Peierls system CuGeO_3 lead to an important reduction of the NMR line widths. These fluctuations are the zero-point motion of the massless phasonic excitations. Furthermore, we show that the discrepancy of X-ray and NMR soliton widths can be understood as the difference between a distortive and a magnetic width. Their ratio is controlled by the frustration of the spin system. By this work, theoretical and experimental results can be reconciled in two important points.Comment: 9 pages, 5 figures included, Revtex submitted to Physical Review

Chapitre 6 - L’innovation, condition de la pérennité des systèmes agroalimentaires localisés

Résumé. La production agroalimentaire artisanale et les produits de terroir ont bien souvent une image traditionnelle, celle de pratiques figées dans le temps, transmises de génération en génération. L’analyse montre au contraire des systèmes agroalimentaires localisés (Syal) confrontés à des besoins permanents d’innovation, pour faire face à des évolutions internes (réduction de la capacité de coordination et d’action collective) et/ou externes (nouvelles contraintes ou opportunités techniques ou commerciales). Face à ces besoins, certains systèmes sont à même d’instaurer des interactions accrues entre acteurs locaux et acteurs extra-locaux, débouchant sur des innovations techniques ou organisationnelles. Le concept de Syal permet alors d’éclairer bien mieux ces processus d’innovation collectifs et localisés que ne le font les schémas diffusionnistes, et de mettre aussi en évidence les voies d’appui

Advancing global & regional reanalyses

This report outlines the structure of and summarizes the recommendations made at the 5th International Conference on Reanalysis (ICR5), attended by 259 participants from 37 countries, in Rome (Italy), on 13-17 November 2017. It first summarizes the conference structure. Then, the key recommendations of ICR5 are given for the five main conference topics: production; observations (data rescue and preparation); data assimilation methods; quality assurance of reanalysis; and applications in science, services, and policymaking. Lastly, five high-level recommendations are proposed to managing agencies on how best to advance the field of reanalyses, which serves tens of thousands of users, via enhanced research, development, and operations

Aerosol indirect effects

Aerosol indirect effects continue to constitute one of the most important uncertainties for anthropogenic climate perturbations. Within the international AEROCOM initiative, the representation of aerosol-cloud-radiation interactions in ten different general circulation models (GCMs) is evaluated using three satellite datasets. The focus is on stratiform liquid water clouds since most GCMs do not include ice nucleation effects, and none of the model explicitly parameterises aerosol effects on convective clouds. We compute statistical relationships between aerosol optical depth (tau a) and various cloud and radiation quantities in a manner that is consistent between the models and the satellite data. cloud droplet number concentration (N d) compares relatively well to the satellite data at least over the ocean. The relationship between (tau a) and liquid water path is simulated much too strongly by the models. This suggests that the implementation of the second aerosol indirect effect mainly in terms of an autoconversion parameterisation has to be revisited in the GCMs. A positive relationship between total cloud fraction (fcld) and tau a as found in the satellite data is simulated by the majority of the models, albeit less strongly than that in the satellite data in most of them. In a discussion of the hypotheses proposed in the literature to explain the satellite-derived strong fcld–tau a relationship, our results indicate that none can be identified as a unique explanation. Relationships similar to the ones found in satellite data between tau a and cloud top temperature or outgoing long-wave radiation (OLR) are simulated by only a few GCMs. The GCMs that simulate a negative OLR - tau a relationship show a strong positive correlation between tau a and fcld. The short-wave total aerosol radiative forcing as simulated by the GCMs is strongly influenced by the simulated anthropogenic fraction of tau a, and parameterisation assumptions such as a lower bound on Nd. Nevertheless, the strengths of the statistical relationships are good predictors for the aerosol forcings in the models. An estimate of the total short-wave aerosol forcing inferred from the combination of these predictors for the modelled forcings with the satellite-derived statistical relationships yields a global annual mean value of −1.5±0.5Wm−2. In an alternative approach, the radiative flux perturbation due to anthropogenic aerosols can be broken down into a component over the cloud-free portion of the globe (approximately the aerosol direct effect) and a component over the cloudy portion of the globe (approximately the aerosol indirect effect). An estimate obtained by scaling these simulated clearand cloudy-sky forcings with estimates of anthropogenic tau a and satellite-retrieved Nd–tau a regression slopes, respectively, yields a global, annual-mean aerosol direct effect estimate of −0.4±0.2Wm−2 and a cloudy-sky (aerosol indirect effect) estimate of −0.7±0.5Wm−2, with a total estimate of −1.2±0.4Wm−2

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

TMT NFIRAOS: adaptive optics system for the Thirty Meter Telescope

NFIRAOS is the first-light adaptive optics system planned for the Thirty Meter Telescope, and is being designed at the National Research Council of Canada's Herzberg Institute of Astrophysics. NFIRAOS is a laser guide star multiconjugate adaptive optics system - a practical approach to providing diffraction limited image quality in the NIR over a 30" field of view, with high sky coverage. This will enable a wide range of TMT science that depends upon the large corrected field of view and high precision astrometry and photometry. We review recent progress developing the design and conducting performance estimates for NFIRAOS