Transdisciplinary participatory-action-research from questions to actionable knowledge for sustainable viticulture development

Viticulture negatively impacts the environment, biodiversity, and human health; however, despite the widely acknowledged challenges that this intensive agricultural activity poses to sustainable development, measures to reduce its invasiveness are constantly being deferred or rebuffed. Constraints to change are linked to vine cultivation methods, the impacts of climate change on vine resilience and disease sensitivity, and socio-economic models, as well as growing criticisms from society. Research and training have thus far failed to provide solutions or mobilise stakeholders on a large scale. Such resistance to sustainable practices development calls into question the effectiveness of knowledge production systems and relations between scientists, winegrowers, and society: Have scientific disciplines overly isolated themselves from each other and from the wider society to the point of losing the capacity to incorporate alternative forms of knowledge and reasoning and achieve collaborative action? Herein, we describe our findings from a participatory action research project that began in Westhalten, France, in 2013 and ultimately spread to Switzerland and Germany over the next 6 years. We show that participatory action research can mobilise long-term collaborations between winegrowers, NGOs, advisers, elected officials, members of civil society, and researchers, despite differing visions of viticulture and the environment. The epistemological framework of this research promotes consensus-building by valuing complexity and dissensus in knowledge and reasoning such that all actors are involved in experimentation and the production of results. From these findings, consensus statements were collectively elaborated in qualitative and quantitative registers. Once acknowledged by the scientific community, these consensus statements became shareable knowledge. We propose that this renewed interdisciplinarity associating the human and social sciences with agronomic and biological sciences in collaboration with stakeholders produces actionable knowledge that mobilises and engages winegrowers to conceive and implement sustainable viticulture on a transnational scale

A reliable absolute palaeointensity determination obtained from a non-ideal recorder

Reliable measurements of the intensity of the palaeomagnetic field are notoriously difficult to obtain. The approach generally taken is to produce multiple estimates per rock unit and assume that those which meet certain minimum standards of technical quality will combine to produce an accurate mean. However, here, using results produced from a package of 20th century basaltic lava flows from Mount Etna in Sicily, we demonstrate that this approach can fail. In this case, the application of typical sets of selection criteria actually introduces bias into the mean determination that we measure. We demonstrate that this is caused by two types of non-ideal behaviour acting in combination. The first is a result of the multidomain grains that the samples contain and the second is caused by differences in the natural and laboratory cooling rates. We discuss means of avoiding these sources of error in future palaeointensity studies performed on ancient rocks. We also develop a new, more general reliability criterion which is effective here and which we argue should be applied wherever possible in future palaeointensity studies in conjunction with standard criteria. It requires two distinct types of materials which both produce some good-quality palaeointensity measurements and uses their range of overlap to constrain the true palaeointensity. Both the application of this criterion and general reliability considerations require that future palaeointensity studies should measure many samples per cooling unit and that these should be as diverse in terms of their rock magnetic properties and cooling histories as possible

First archeointensity determinations on Maya incense burners from Palenque temples, Mexico: New data to constrain the Mesoamerica secular variation curve

International audienceWe present archeointensity data carried out on pieces of incense burners from the ancient Maya city of Palenque, Chiapas, Mexico, covering much of the Mesoamerican Classic period, from A.D. 400 to A.D. 850. We worked on pieces from 24 incense burners encompassing the five Classic ceramic phases of Palenque: Motiepa (A.D. 400-500), Cascadas (A.D. 500-600), Otulum (A.D. 600-700), Murcielagos (A.D. 700-770), and Balunté (A.D. 770-850). All the samples come from highly elaborate, flanged pedestal of incense burners that are undoubtedly assigned to a ceramic phase by means of their iconographic, morphological and stylistic analyses. Archeointensity measurements were performed with the Thellier-Thellier's method on pre-selected samples by means of their magnetic properties. We obtained archeointensities of very good technical quality from 19 of 24 pieces, allowing the determination of a precise mean value for each ceramic phase, between View the MathML source29.1±0.9μT and View the MathML source32.5±1.2μT. The firing temperatures of ceramics were estimated with Mössbauer spectroscopy between 700 °C and 1000 °C. These values ensure that a full thermo-remanent magnetization was acquired during the original heating. Our results suggest a relative stability of the field intensity during more than 400 years in this area. The abundance of archeological material in Mesoamerica contrasts with the small amount of archeomagnetic data available that are, in addition, of uneven quality. Thus, it is not possible to establish a trend of intensity variations in Mesoamerica, even using the global databases and secular variation predictions from global models. In this context, our high technical quality data represent a strong constraint for the Mesoamerican secular variation curve during the first millennium AD. The corresponding Virtual Axial Dipole Moments (VADM) are substantially smaller than the ones predicted by the last global geomagnetic models CALS3k.4, suggesting the need for additional data to develop a regional model and a reference curve for Mesoamerica

Palaeomagnetism of the upper volcanic supergroup, southern part of the Sierra Madre Occidental, Mexico

International audienceAsh flow tuffs, or ignimbrites have been recently proposed to be a good material for palaeointensity determination. In this paper, we present a multidisciplinary study, combining geochronology, petrology, rock magnetism and palaeomagnetism, carried out on Oligocene to Early Miocene ignimbrites and related flows from the southern part of the Sierra Madre Occidental. Two new 40Ar/39Ar ages were determined for ignimbrites; 20.4 ± 0.2 Ma (the youngest age obtained so far in this area) and 29.2 ± 0.5 Ma. Density measurements, as a proxy for welding, proved to be extremely useful to estimate the emplacement temperature and the origin of the magnetizations carried by the ignimbrites. After alternating field and thermal demagnetizations, the mean palaeomagnetic pole (Lat = 66.8°N; Long = 180.5°E; Kappa = 142; A95 = 6.3°), calculated for the period 28-31 Ma, is in close agreement with our only Miocene determination. Comparison with the North America Synthetic Apparent Polar Path indicates a net counter-clockwise vertical axis rotation of about 10 ± 4° compared to stable North America, which occurred likely during the last extensional episode in the Late Miocene (ca. 12-9 Ma). Palaeointensity estimates, obtained with the Thellier-Coe method, are mainly questionable and should not be used for global interpretation. Therefore, these ignimbrites are not a viable material for reliable palaeointensity determinations

Rock magnetism and microscopy of the Jacupiranga alkaline-carbonatitic complex, southern Brazil

International audienceThis study of the Cajati deposit provides evidence that the ore was neither purely hydrothermal, nor volcanic in origin, as previous workers have proposed. The ores were formed from magnetite-rich magmas, hydrothermally altered and intruded at an indicated crustal depth in excess of 500 m. The mineralogical and textural association between magnetite and magnesioferrite in the carbonatite, and between the titanomagnetite and magnesioferrite-Ti mineralization in the pyroxenite of hedenbergite, seems to be analog mineralizations strongly related to the ionic substitution of Fe2+ by Mg. Relatively high Q ratios (>= 5) for Jacupirangite-pyroxenite may indicate a thermo remanent magnetization (TRM) by the ore during post-metamorphic cooling, however it call also be developed from chemical remanent magnetization (CRM). Vector plots for the pyroxenite samples show reasonably linear and stable magnetic components. The intensity decay Curves show that only two components of magnetizations are likely present. Continuous susceptibility measurements with increasing temperature show that the main magnetic phase seems to be magnetite. Maghemite is probably produced during the cooling process. Susceptibility recorded from low temperature (liquid nitrogen (- 196 degrees C)) to room temperature produces typical Curves. indicating Verwey transition of magnetite. Hysteresis parameters point Out that nearly all values fill in a novel region of the Day plot, parallel to but below magnetite SD + MD mixing curves

Archaeomagnetic dating and magnetic characterization of ceramics from the Paquimé, Casas Grandes region, Chihuahua, Mexico

International audienceCasas Grandes is a prehistoric culture area located between Chihuahua, northern Mexico, and New Mexico, southwest of United States of America. It had an intense occupation with large buildings during the ceramic period, from 0 to 1450 CE, developing very particular painted potteries. In this study, magnetic properties and archaeointensity experiments were investigated on two special ceramic types called Mimbres and polychrome Ramos. They come from four archaeological sites from Casas Grandes region in northern Chihuahua: Paquimé, Villa Ahumada, Galeana, and Samalayuca. Archaeological timing and typology assign Mimbres and Ramos to an age period between 900 and 1450 CE, but no absolute ages are available. Magnetic properties show that Mimbres and Ramos have different magnetomineralogical properties, suggesting that pottery making materials were different. Mean archaeointensity results were obtained from nine different pottery sherds, five from Mimbres and four from Ramos polychrome, for a total of 35 specimens. Intensity value range from 49 to 59 µT for Mimbres type and from 41 to 49 µT for Ramos type. Archaeomagnetic dating was performed using the SHAWQ2k global model and the Maghoub regional paleosecular variation curve. Archaeomagnetic dating give an absolute age range of 960–1100 CE for Mimbres type, and of 1300–1600 CE for Ramos samples, confirming that both ceramic types were manufactured at different times. These results highlight the potential of archaeomagnetism to precise the chronological framework of Casas Grandes culture

Linking the knowledge and reasoning of dissenting actors fosters a bottom-up design of agroecological viticulture

Wine growing has a high economic value globally, and vineyards, with their centenarian grape varieties, are an integral part of our societies. Yet with the use of spraying to control pathogens and weeds, mainstream viticulture has become a big pesticide consumer. Criticism of this conventional type of viticulture and its environmental/health impacts is increasing strongly throughout society. Until now, mainstream 'top-down' scientific-technical developments have focused on breeding for new varieties and on designing new agronomic models. In parallel, organic and biodynamic practices have been developing alternatives. Either way, changes do not develop on the expected time scale. We posit that the diversity of actors concerned, from winegrowers to technical advisers, consumer associations, conservationists, elected representatives, citizens, and scientists, all contribute to the perpetuation of a constrained situation, through their differences in perspectives and practices, positions, knowledge, and reasoning. To untangle this situation, we brought together these dissenting actors. With a view to resolving the epistemological challenges, we then characterized four types of knowledge, along with the reasoning in play, and designed a tetrahedral model to legitimize and inter-relate them. This tetrahedron supported co-construction of a collective epistemology after a paradigm shift, in which the dissensus became a resource on numerous occasions. We then highlighted masked double-bind situations and went further, developing a seven-step Argonaut to conduct the project. New practices were designed, to do away with herbicides and develop ecological grassing. They were implemented on a large scale in vineyards, within a short time frame, while enhancing the value of a neighbouring nature reserve. Projects currently underway in Switzerland, Germany, and France suggest that differences in knowledge are enriching, and yet that the reasoning at play fit with our tetrahedron model. We thus show that dissenting actors can dissolve agronomic/economic/ecological dilemmas, while acting under uncertainty, and foster agroecology development

Natural magnetite nanoparticles from an iron-ore deposit: size dependence on magnetic properties

International audienceWe report oil the discovery of magnetite nanoparticles ranging in size from 2 to 14 full in the mineralized zones of the Pena Colorada iron-ore deposit, southern Mexico. Micrometric scale magnetite was magnetically reduced and divided into distinct size ranges: 85-56 mu m, 56-30 mu m, 30-22 mu m, 22-15 mu m, 15-10 mu m, 10-7 mu m and 7-2 mu m. Nanometric-scale magnetite in the size range 2-14 nm was identified. The magnetite was characterized by X-ray diffraction, transmitted and reflected light microscope, high-resolution transmission electron microscopy (TEM), high angle annular dark field, Mossbauer spectroscopy and its magnetic properties. Crystallographic identification of nanostructures Was performed using high-resolution TEM. Characteristic changes were observed when the particles make the size transition from micro- to nanometric sizes, as follows: (1) frequency-dependent magnetic Susceptibility percentage (chi FD%) measurements Show high Values (13%) for the 2-14 nm fractions attributed to dominant fractions of superparamagnetic particles; (2) variations of chi FD% < 4.5% in fractions of 56-0.2 mu m occur in association with the presence of microparticles formed by magnetite aggregates of nanoparticles (< 15 nm) embedded in berthierine; (3) Mossbauer spectroscopy results identified a superparamagnetic fraction; (4) nanometric and 0.2-3 mu m grain size magnetite particles require a magnetic field up to 152 mT to reach saturation during the isothermal remanent magnetization experiment; (5) coercivity and remanent magnetization of the magnetite increase when the particle size decreases, probably due to parallel Coupling effects; (6) two-magnetic Susceptibility versus temperature experiments of the same 2-14 nm sample show that the reversibility during the second heating is due to the formation of new magnetite nanoparticles and growth of those already present. during the first heating process

The Acigöl Lake near Denizli, Turkey: a window on the environment of the Kocabaş hominin at 1.2 Ma

International audienc