Accompagner les acteurs dans le changement de leur système Un jeu de rôles pour des projets collectifs d'irrigation au Tadla, Maroc

Les petites exploitations agricoles du périmètre irrigué du Tadla font actuellement face à de profonds changements environnementaux, institutionnels et économiques. Les ressources hydriques diminuent, l'Etat marocain se repositionne vis-à-vis de la gestion des grands périmètres irrigués et les marchés s'ouvrent (libre-échange). L'organisation des petites exploitations autour de projets collectifs d'irrigation (PCI) visant la reconversion à l'irrigation localisée représente une solution prometteuse pour faire face à cette nouvelle situation. Ces PCI nécessitent un profond changement du système traditionnel des agriculteurs, tant sur le plan technique qu'organisationnel. Ce changement est mis en oeuvre à travers une action collective innovante dont l'accompagnement requiert de nouvelles formes d'intervention. S'inscrivant dans un processus participatif plus général visant à soutenir la mise en oeuvre des PCI au Tadla, un jeu de rôles a ainsi été développé. A travers cet exercice, des groupes pilotes d'agriculteurs et de gestionnaires ont pu expérimenter, d'une manière virtuelle, les différentes étapes de la mise en oeuvre d'un PCI. Ce jeu de rôles a été utilisé pour développer, en anticipation, un savoir commun sur les PCI, ce qui a permis de renforcer l'implication et le pouvoir de décision des agriculteurs vis-à-vis du projet collectif, tout en facilitant les étapes ultérieures du processus. On a pu ainsi formaliser les attentes de ces derniers et révéler les questions problématiques. Par ailleurs, ce jeu de rôles s'est avéré être un outil efficace pour révéler les projets individuels des agriculteurs. Cet outil participatif ouvre une voie prometteuse dans le développement de nouvelles formes d'intervention destinées à accompagner des acteurs dans l'évolution de leur système. Au Tadla, le transfert de cette approche à des organisations professionnelles locales pourrait permettre le développement des PCI, et leur accompagnement à plus large échelle, spatiale et temporelle

Performance comparison of aperture-less and confocal infrared microscopes

We compared hyperspectral infrared raster maps and images for contrast, definition and resolution of the same samples recorded with a confocal microscope coupled with a synchrotron radiation source vs a Focal Plane Array (FPA) detector equipped microscope. Biological samples (hair and skin sections) and astrophysics samples (meteoritic grains) were used. The samples presented are a few microns in size, such as embedded particles, a single unique cell or thin layer. Our results show that the actual spatial resolution and contrast of FPA images were lower than spectral maps from the confocal microscope. The FPA microscope also produced measurements that lacked accuracy: size of sample features and peak intensity were inaccurately estimated. More surprisingly, the intensity of absorption peaks in the FPA images was lower than the intensity measured from the same sample with a confocal microscope. Our measurements underlined the complementarity of FPA and confocal microscopes. FPA can be used to quickly measure the overall composition of a sample and detect the distribution of its components, but may fail measuring the exact chemical composition of the small features and may not detect weak spectral differences between adjacent positions. The averaging effect of aperture-less systems not only affects image resolution but also lowers their spectral accuracy. Confocal microscopes are inherently slower but give a more accurate measurement of the local composition at the diffraction limit

Isotopic and textural analysis of giant unmelted micrometeorites – identification of new material from intensely altered 16O-poor water-rich asteroids

Bulk oxygen isotope data has the potential to match extraterrestrial samples to parent body sources based on distinctive δ18O and Δ17O ratios. We analysed 10 giant (>500 μm) micrometeorites using combined micro-Computer Tomography (μCT) and O-isotope analysis to pair internal textures to inferred parent body groups. We identify three ordinary chondrite particles (L and LL groups), four from CR chondrites and the first micrometeorite from the enstatite chondrite (EH4) group. In addition, two micrometeorites are from hydrated carbonaceous chondrite parent bodies with 16O-poor isotopic compositions and plot above the terrestrial fractionation line. They experienced intense aqueous alteration, contain pseudomorphic chondrules and are petrographically similar to the CM1/CR1 chondrites. These micrometeorites may be members of the newly established CY chondrites and/or derived from the enigmatic “Group 4” micrometeorite population, previously identified by Yada et al., 2005 [GCA, 69:5789-5804], Suavet et al., 2010 [EPSL, 293:313-320] (and others). One of our 16O-poor micrometeorite plots on the same isotopic trendline as the CO, CM and CY chondrites – “the CM mixing line” (with a slope of ∼0.7 and a δ17O intercept of -4.23‰), this implies a close relationship and potentially a genetic link to these hydrated chondrites. If position along the CM mixing line reflects the amount of 16O-poor (heavy) water-ice accreted onto the parent body at formation, then the CY chondrites and these 16O-poor micrometeorites must have accreted at least as much water-ice as CM chondrites but potentially more. In addition, thermal metamorphism could have played a role in further raising the bulk O-isotope compositions through the preferential loss of isotopically light water during phyllosilicate dehydration. The study of micrometeorites provides insights into asteroid belt diversity through the discovery of material not currently sampled by larger meteorites, perhaps as a result of atmospheric entry biases preventing the survival of large blocks of friable hydrated material

Participatory analysis for adaptation to climate change in Mediterranean agricultural systems: possible choices in process design (versão Pre Print)

There is an increasing call for local measures to adapt to climate change, based on foresight analyses in collaboration with actors. However, such analyses involve many challenges, particularly because the actors concerned may not consider climate change to be an urgent concern. This paper examines the methodological choices made by three research teams in the design and implementation of participatory foresight analyses to explore agricultural and water management options for adaptation to climate change. Case studies were conducted in coastal areas of France, Morocco, and Portugal where the groundwater is intensively used for irrigation, the aquifers are at risk or are currently overexploited, and a serious agricultural crisis is underway. When designing the participatory processes, the researchers had to address four main issues: whether to avoid or prepare dialogue between actors whose relations may be limited or tense; how to select participants and get them involved; how to facilitate discussion of issues that the actors may not initially consider to be of great concern; and finally, how to design and use scenarios. In each case, most of the invited actors responded and met to discuss and evaluate a series of scenarios. Strategies were discussed at different levels, from farming practices to aquifer management. It was shown that such participatory analyses can be implemented in situations which may initially appear to be unfavourable. This was made possible by the flexibility in the methodological choices, in particular the possibility of framing the climate change issue in a broader agenda for discussion with the actors

Isotopically Heavy Micrometeorites—Fragments of CY Chondrite or a New Hydrous Parent Body?

Cosmic dust grains sample a diverse range of solar system small bodies. This includes asteroids that are not otherwise represented in our meteorite collections. In this work we obtained 3D images of micrometeorite interiors using tomography before collecting destructive high‐precision oxygen isotope measurements. These data allow us to link textures in unmelted micrometeorites to known chondrite groups. In addition to identifying particles from ordinary chondrites, CR and CM chondrites we report two micrometeorites derived from an anomalous 16O‐poor source (δ17O: +16.4‰, δ18O: +28.4‰, and Δ17O: +1.4‰). Their compositions overlap with a previously reported micrometeorite (TAM50‐25) from Suttle et al. (2020), https://doi.org/10.1016/j.epsl.2020.116444 (EPSL: 546:116444). These particles represent hydrated carbonaceous chondrite material derived either from a new group or from the CY chondrites (thereby extending the isotopic range of this group). In either scenario they demonstrate close petrographic and isotopic connections to the CO‐CM chondrite clan. Furthermore, their position in O‐isotope space makes them the most likely candidate for the parent body of the anomalous “group 4” cosmic spherules previously reported by Suavet et al. (2010), https://doi.org/10.1016/j.epsl.2010.02.046 (EPSL: 293:313‐320) and several subsequent isotopic studies. We conclude that the “group 4” cosmic spherules originate from hydrated C‐type asteroid parents

GIADA microbalance measurements on board Rosetta: submicrometer- to micrometer-sized dust particle flux in the coma of comet 67P/Churyumov-Gerasimenko

Context. From August 2014 to September 2016, Rosetta escorted comet 67P/Churyumov-Gerasimenko (67P) during its journey around the Sun. One of the aims of Rosetta was to characterize cometary activity and the consequent formation of dust flux structures in cometary comae. Aims: We characterize and quantify the submicrometer- to micrometer-sized dust flux that may be shaped in privileged directions within the coma of 67P inbound to and outbound from perihelion. Methods: The in situ dust-measuring instrument GIADA, part of the Rosetta/ESA payload, consisted of three subsystems, one of which was the Micro Balance Subsystem (MBS), composed of five quartz crystal microbalances. From May 2014 to September 2016, MBS measured the submicrometer- to micrometer-sized deposited dust mass every 5 min. Results: We characterized the submicrometer- to micrometer-sized dust mass flux in the coma of 67P. The anti-sunward and the radial direction are preferred, and the flux is higher in the anti-sunward direction. The measured cumulative dust mass in the anti-sunward direction is 2.38 ± 0.04 × 10-7 kg, and in the radial direction, it is 1.18 ± 0.02 × 10-7 kg. We explain the anti-sunward dust flux as the effect of nonuniform gas emission between the night- and dayside of the nucleus, which acts in combination with the solar radiation pressure. We compared the cumulated dust mass of particles ≤5 μm with particles ≥100 μm. The retrieved ratio of ≈2% implies a differential size distribution index of ≈-3.0, which confirms that particles of size ≥0.1 mm dominate the dust coma cross-section of 67P during the entire orbit. Conclusions: Submicrometer- to micrometer-sized dust mass flux measurements were made for the first time from the arising of cometary activity until its extinction. They indicate that these particles do not provide a substantial optical scattering in the coma of 67P with respect to the scattering caused by millimeter-sized particles. In addition, MBS data reveal that the measured dust flux is highly anisotropic: anti-sunward plus radial

Participatory transport planning the experience of eight european metropolitan regions

This chapter presents experience with participatory transport planning in eight European metropolitan regions: Ljubljana, Oslo, Gothenburg, Helsinki, Budapest, Rome, Porto and Barcelona. These metropolitan regions answered the questionnaire on strengths, weaknesses and needs and an in-depth questionnaire on participatory transport planning. The results were presented at a workshop, where representatives from these eight metropolitan regions shared their experience in two workshop sessions, one dealing with the key stakeholders in participatory transport planning and the other dealing with ways to get them involved. The findings show that stakeholder involvement differs between the local and regional levels. Participants engagement is greater at the local level, where measures are more concrete and less abstract. The participatory planning process takes longer than the traditional planning processes, but it can ease the implementation of the project/measure to the extent that it justifies the additional resources and time. It is of crucial importance to include all the relevant stakeholders, to provide an experienced facilitator and, above all, to include the results in the final plans and policies. Although there are differences in the participatory planning culture between the countries and regions involved, the use of participatory methods in transport planning is becoming increasingly important. Document type: Part of book or chapter of boo

Calathus: A sample-return mission to Ceres

Ceres, as revealed by NASA's Dawn spacecraft, is an ancient, crater-saturated body dominated by low-albedo clays. Yet, localised sites display a bright, carbonate mineralogy that may be as young as 2 Myr. The largest of these bright regions (faculae) are found in the 92 km Occator Crater, and would have formed by the eruption of alkaline brines from a subsurface reservoir of fluids. The internal structure and surface chemistry suggest that Ceres is an extant host for a number of the known prerequisites for terrestrial biota, and as such, represents an accessible insight into a potentially habitable “ocean world”. In this paper, the case and the means for a return mission to Ceres are outlined, presenting the Calathus mission to return to Earth a sample of the Occator Crater faculae for high-precision laboratory analyses. Calathus consists of an orbiter and a lander with an ascent module: the orbiter is equipped with a high-resolution camera, a thermal imager, and a radar; the lander contains a sampling arm, a camera, and an on-board gas chromatograph mass spectrometer; and the ascent module contains vessels for four cerean samples, collectively amounting to a maximum 40 g. Upon return to Earth, the samples would be characterised via high-precision analyses to understand the salt and organic composition of the Occator faculae, and from there to assess both the habitability and the evolution of a relict ocean world from the dawn of the Solar System.The attached document is the authors’ final accepted version of the journal article provided here with a Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) Creative Commons Licence. You are advised to consult the publisher’s version if you wish to cite from it.

Bibliographie de travaux français (1950 à 1974)

Dionnet M.-C., Sachet M. Bibliographie de travaux français (1950 à 1974) . In: Bulletin de l'Association de géographes français, N°420-421, 51e année, Novembre-décembre 1974. pp. 319-322