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The demand for cocoa has increased over the past years following the growth of cocoa-based products linked to the rise in living standard in highly populated countries. Cacao industry is therefore currently facing the dilemma of producing more cacao while ensuring its sustainability. Cacao monocrops and agroforestry systems (AFS) are two contrasting ways to produce cocoa, yet their impact on yields, contribution to farmer livelihood, cocoa quality remains understudied. Therefore, we reviewed existing literature comparing (1) monocrop cacao farming systems with (2) simple or (3) complex AFS. We found 19 comparisons of the cocoa yields in monocrops and simple AFS and 20 comparisons of monocrop and complex AFS. Three main research findings derive from this work. First, in about one third of cases, cacao trees yield more (or equally) in AFS than in monocrops. However, when considering only simple AFS, cacao trees yield more or equal to cacao monocrop in 52% of the cases. Second, cocoa AFS yields an average of 14% less than cacao monocrop. Yet, on average simple AFS yielded 2% less than cacao monocrops. Finally, there are too little elements to draw conclusions about the nexus between cocoa quality and cacao tree cultivation system.

International audience; Multidisciplinary Design Optimization (MDO) methods aim at adapting numerical optimization techniques to the design of engineering systems involving multiple disciplines or components. Among MDO architectures, various ones are considering the resolution of the Multidisciplinary Design Analysis (MDA). In our study, the system of interest being an aircraft, the resolution of the MDA will be provided by the Future Aircraft Sizing Tool with Overall Aircraft Design (FAST-OAD), a point mass approach that estimates the required fuel and energy consumption for a given set of top-level aircraft requirements. In this context, a large number of mixed continuous, integer and categorical variables that arise from aircraft design has to be tackled by the optimization process. Recently, there has been a growing interest in mixed variables constrained Bayesian optimization based on Gaussian process surrogate models. In this setting, most existing approaches severely increase the dimension of the covariance matrix related to the surrogate. In fact, the construction of the Gaussian process model may not be scalable to practical applications involving a large number of mixed variables. In this paper, we address this issue by constructing a covariance kernel for the surrogate model that depends on only a few hyperparameters. The new kernel is constructed based on the information obtained from the partial least squares method. The obtained numerical results lead to interesting results for the optimization of a baseline aircraft and to reduce the fuel consumption of "DRAGON", a new hybrid electric propulsion aircraft, with a high number of mixed variables and for a small budget of time-consuming evaluations.

Background: We aimed to assess the effectiveness of two doses of mRNA COVID-19 vaccines against COVID-19 with the original virus and other lineages circulating in France. Methods: In this nationwide case-control study, cases were SARS-CoV-2 infected adults with onset of symptoms between 14 February and 3 May 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire on recent activity-related exposures and vaccination history. Information about the infecting virus was based on a screening RT-PCR for either B.1.1.7 or B.1.351/P.1 variants. Findings: Included in our analysis were 7 288 adults infected with the original SARS-CoV-2 virus, 31 313 with the B.1.1.7 lineage, 2 550 with B.1.351/P1 lineages, and 3 644 controls. In multivariable analysis, the vaccine effectiveness (95% confidence interval) seven days after the second dose of mRNA vaccine was estimated at 88% (81-92), 86% (81-90) and 77% (63-86) against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively. Recent (2 to 6 months) history of virologically confirmed SARS-CoV-2 infection was found to be 83% (76-88), 88% (85-91) and 83% (71-90) protective against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively; and more distant (> 6 months) infections were 76% (54-87), 84% (75-90), and 74% (41-89) protective against COVID-19 with the original virus, the B.1.1.7 lineage, and the B.1.351/P.1 lineages, respectively. Interpretation: In real-life settings, two doses of mRNA vaccines proved to be effective against COVID-19 with the original virus, B.1.1.7 lineage and B.1.351/P.1 lineages. Funding: Institut Pasteur, Research & Action Emerging Infectious Diseases (REACTing), Fondation de France (Alliance “Tous unis contre le virus”).

International audience; Manufacturing of microsystems based on complex three-dimensional microstructures requires critical steps such as mass calibrations and integration process. However, such steps involve several manipulation steps which are not well controlled thus the fragile 3D microstructures could be damaged or destroyed. In this work, we have demonstrated an AFM based direct mass measurement and manufacturing of 3D helical microswimmer. The proposed method shows to be rapid, repeatable and minimally-destructive thanks to the precise force control and manipulation by AFM. The proposed micromanipulation steps consist of the pick-measure-integrate manipulation steps using van der Waals force-based attachment and the mass measurement by resonant frequency shift. For the testing structures, we fabricated the 6 different types of 3D helical microswimmers vertically fabricated on the conical shape microneedle supports for uniform surface metallization and facile detachment. With the mass measurement sensitivity of 25 Hz/pg and the direct integration to microfluidics, we successfully demonstrated the 3D propulsion and non-contact micromanipulation by 3D helical microswimmer in microfluidics.

International audience; Mass measurements of complex three-dimensional microstructures are essential to the design and development of microsystems. However, the mass measurements of such microstructures require several manipulation steps which are not well controlled. We have demonstrated a rapid, reliable and lessdestructive on-chip mass measurement method by incorporating with AFM micromanipulation. It is based on AFM pick-measureplace micromanipulation using Van der Waals attraction and the mass measurement by resonant frequency shift. The measurement sensitivity revealed to be 25 Hz/pg and it could be promising to characterize MEMS with complex geometries and composite materials.

Perennial grain crops are currently being developed, yet little is known about farmer interest in these new crops. We conducted an online survey in France and the United States to evaluate interest in perennial grains. Results show that 57% of the farmers who responded reported they were &ldquo, interested&rdquo, or &ldquo, very interested&rdquo, in growing perennial grains, whereas 41% reported they needed more information. Respondents consistently ranked &ldquo, to increase or maintain farm profitability&rdquo, and &ldquo, to improve soil health&rdquo, among the top reasons why they were interested in growing perennial grains. Reasons why farmers were interested, as well as their concerns about growing perennial grains, differed by country and farm type (i.e., conventional vs. organic). More farmers in France than in the United States ranked &ldquo, to reduce labor requirements&rdquo, and more conventional farmers than organic farmers ranked &ldquo, to reduce inputs&rdquo, among their top reasons for their interest. Farmers were also asked about integration strategies and management. More farmers in the United States than in France and more conventional farmers than organic farmers reported that they were interested in dual-purpose perennial crops that can be harvested for both grain and forage. Results from this survey can guide future perennial grain research and development.

International audience; Sustainable cropping systems that balance agricultural productivity and ecological integrity are urgently needed. Overreliance on soil tillage and herbicides to manage weeds has resulted in a number of major environmental problems including soil erosion and degradation, biodiversity loss, and water quality impairment. Combining organic farming and conservation agriculture is a viable alternative to address these challenges. In particular, mulch-based no tillage systems can be used to reduce tillage in organic production, improving soil quality while decreasing labor and fuel requirements. This technique involves planting cash crops directly into terminated cover crops that remain on soil surface and serve as mulch to prevent weeds establishment and protect soil from erosion. Despite potential benefits, adoption of organic mulch-based no tillage is limited due to challenges with cover crop termination, weed suppression, and yields. Here, we (i) review international research on organic mulch-based no tillage systems (soybean and maize), (ii) identify production issues that limit the success of this technique, and (iii) outline research priorities. As result, organic mulch-based no tillage is knowledge intensive and requires advanced planning and careful management of the cover crop. Primary challenges include timely cover crop establishment and termination, nutrient management, reduced soil temperature and moisture at planting, and achieving adequate seed-to-soil contact when planting into thick mulch on soil surface. Long-term research is needed to better understand the effects of this technique production on soil health and on the broader environmental and economic impacts. To increase adoption of organic mulch-based no tillage, future research should focus on (i) screening species and cultivars to identify cover crop and crop combinations that optimize cropping system performance and (ii) developing equipment for improving cover crop termination and seed placement. Research conducted in partnership with farmers will be valuable for developing guidelines and increasing adoption of this technique.

Nitrogen (N) deficiency and weed infestation are the main factors limiting the yield and quality of organic soft winter wheat (Triticum aestivum L.). If forage legumes are associated with wheat, simultaneously or successively, they can help to reduce the impact of limiting factors through the ecological services they provide. The aim of this study was to evaluate two intercropping strategies to increase soft winter wheat yield and protein content and improve the provided ecological services (mainly N provisioning and weed control) by white clover (Trifolium repens L.). White clover (Trifolium repens L. cv Aberdai) was intercropped with soft winter wheat (Triticum aestivum L. cv Renan) under organic conditions. Two strategies were compared, simultaneous intercropping versus relay intercropping using three field experiments. A control treatment with sole wheat crop was included in the three field experiments. Fertilization management on organic wheat was also tested (0 versus 100 kg N applied at spring time) to evaluate its incidence on cash and cover crop yields and protein content. White clover shoot dry matter (DM) was significantly higher in simultaneous intercropping compared to relay intercropping at wheat harvest (2.2 vs. 0.1 Mg DM ha−1) and at cover destruction (4.5 vs. 3.1 Mg DM ha−1). Wheat grain yield was not affected by the intercropping strategy while the protein content was significantly lower under simultaneous intercropping system (9.1% of the grain DM) compared to relay intercropping or in wheat as sole crop (10.0% of the grain DM). At cover destruction, both simultaneous and relay intercropped white clover significantly decreased weed shoot DM compared to sole wheat crop (−1.4 Mg DM ha−1 for relay intercropping and −1.8 Mg DM ha−1 for simultaneous intercropping). In comparison to relay intercropping strategy, N accumulation in white clover shoot DM was higher under simultaneous intercropping strategy at wheat harvest (52 vs. 2 kg N ha−1) and at cover destruction (123 vs. 83 kg N ha−1). In conclusion, our study has highlighted the positive effect of combining a simultaneous intercropping strategy with high N availability to guarantee a sufficient level of legume shoot DM as rapidly as possible to increase both N accumulation and weed control services, thus reducing the risk of impairing winter wheat yield and protein content.

International audience; Controlling groundwater diffuse pollution induced by agricultural practices remains a significant challenge and has been receiving strong attention in the European Union (EU) for the last 25 years. The EU's Nitrates Directive (91/676EC) and its associated Nitrate Vulnerable Zone (NVZ) legislation were recently revised in France in 2015, requiring farmers to adopt measures and then modify their agricultural practices to protect water resources. Yet these measures are not always implemented in an optimal way, thus limiting improvement of groundwater quality. Based on semi-directive interviews with 14 French farmers, we developed an innovative farm-scale method composed of four steps. First, we described how these farmers implemented Nitrate Directive measures. Second, we evaluated their impact on farm structure and third their consistency with farmer's strategy. Fourth, we assessed their suitability for farm management as an integrative analysis of the previous step. Through this approach, we identified 3 types of farm management. A group of "Beyond Regulation" composed of farmers for whom Nitrate Directive measures are suitable for their farm management. They optimally implement these measures to reduce pressure on groundwater quality. For the second group named "Soft Regulation-constraints", Nitrate Directive measures are less suitable for their farm management because they have another lucrative activity than cash crop production. This group could benefit from a redesign of the measures, changing from means- to result-oriented obligation in order to take into account the local conditions and also their farm management constraints. For the third group, denoted as "Strong Regulation-constraints", ND measures are not suitable for their farm management. The way they implement measures is usually not optimal to reduce pressure on groundwater quality. We suggest that, investing in an "action-learning" program for such farmers could make them understand the usefulness of this regulation and help them to make the measure implementation suitable for their farm management. This farm-scale method could be used further for water management stakeholders to (i) evaluate the suitability of measures from Water Policy for the diversity of farm management or (ii) design suitable measures for the diversity of farm management on a territory subjected to groundwater pollution issue.

Two-dimensional (2D) materials have recently been the focus of extensive research. By following a similar trend as graphene, other 2D materials including transition metal dichalcogenides (MX2) and metal mono-chalcogenides (MX) show great potential for ultrathin nanoelectronic and optoelectronic devices. Despite the weak nature of interlayer forces in semiconducting MX materials, their electronic properties are highly dependent on the number of layers. Using scanning tunneling microscopy and spectroscopy (STM/STS), we demonstrate the tunability of the quasiparticle energy gap of few layered gallium selenide (GaSe) directly grown on a bilayer graphene substrate by molecular beam epitaxy (MBE). Our results show that the band gap is about 3.50 +/-0.05 eV for single-tetralayer (1TL), 3.00 +/-0.05 eV for bi-tetralayer (2TL) and 2.30 +/-0.05 eV for tri-tetralayer (3TL). This band gap evolution of GaSe, in particularly the shift of the valence band with respect to the Fermi level, was confirmed by angle-resolved photoemission spectroscopy (ARPES) measurements and our theoretical calculations. Moreover, we observed a charge transfer in GaSe/graphene van der Waals (vdW) heterostructure using ARPES. These findings demonstrate the high impact on the GaSe electronic band structure and electronic properties that can be obtained by the control of 2D materials layer thickness and the graphene induced doping.

Purpose Exploring the ways in which innovation can serve to create better and more integrated social, environmental, and economic enterprises is a key challenge. How firms innovate and change depends strongly on their management models. Permaculture concepts and principles could help the transition toward more sustainability. The purpose of this paper is to understand how management models could rely on Permaculture principles to facilitate innovations and changes toward sustainability. Design/methodology/approach This paper helps meet this challenge by exploring possible innovative management models that could help in pursuing sustainability by aligning enterprises with socio-ecological realities. The possible innovative management models built on the Permaculture concepts will be the object of analysis for this study. Findings The literature review shows that there could be innovative management models built on the Permaculture concepts, a potential alternative to western “traditional” management models. They would give preference to long-term objectives, intrinsic motivation, emergent coordination, and collective wisdom in decision making. Originality/value It is strategically important to find new concepts, models, methods, and practices that will lead society to be ecologically sustainable and socially responsible, besides being economically efficient. These socio-cultural and economic challenges are central to the design and construction of a society in which all individuals feel integrated and responsible.

Resilience is one of the three core properties of social‐ecological systems, mixing adaptability and transformability. Flexibility can be defined in terms of diversity of procedures and the speed at which they can be mobilized by one organization. The analyses performed are presented in terms of levers that farmers can deploy to protect their management systems against market uncertainty. These levers differ depending on farmer standpoints, objectives, lessons learned, the collective organizations they work with, the standards and specifications they work to, etc. It is equally important to identify the interplays between overarching and underlying scale levels for the system studied and to hone in on the dynamics at work during periods of transition. Adaptive capacities of farm systems are closely linked to how the farmer perceives the situations to manage, according to his aims, to his behaviour face to risk and to his idea of what is his job. We propose to use different words to describe the properties of farming systems to cope with changes, according to the level within the system: “adaptive capacity” or “plasticity” for the animal level, “resilience” for the biotechnical level and “flexibility” for the whole system, including the manager. We think there is a real challenge working at each level on transition periods and processes, as farming systems will have more and more to adapt face to unpredic events.

We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20 GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets., Comment: 17 pages, 14 figures. Submitted to Eur. Phys. J. A

International audience; This article focuses on spallation reactions, i.e. interactions of energetic nucleons, basically with a kinetic energy in the 100 MeV to a few GeV range, with a target nucleus. These processes are described rather successfully by the so-called Intranuclear Cascade (INC) plus evaporation models. They can be viewed as a first stage of nucleon-nucleon collisions, ejecting fast particles, followed by evaporation of slow particles from the target remnant. These cascade + evaporation models have, now, globally reached a high level of predictive power, owing in particular to successive research programs. The present work, which is an outcome of one of these programs, the recent European Union ANDES research program, deals with a set of reactions (or observable quantities), which can be due to a single collision, such as the one-nucleon removal reactions or the quasi-elastic elastic process. A survey of the experimental data is presented, which allows to clearly point out that, often, the INC models are unsatisfactory for the description of these peculiar events, whereas they are rather successful for the rest of the experimental data. This paradoxical situation is tentatively related to quasi-particle effects which are neglected in INC models.

In organic agriculture, weeds and nitrogen deficiency are the main factors that limit crop production. The use of relay-intercropped forage legumes may be a way of providing ecological services such as weed control, increasing N availability in the cropping system thanks to N fixation, reducing N leaching and supplying nitrogen to the following crop. However, these ecological services vary considerably depending on the forage legume biomass. The aim of this study was to identify factors that affect forage legume establishment and growth to help farmers adjust the management of the cover crop. Sixteen field experiments were conducted over a period of five years. In each experiment, winter wheat was grown as sole crop or intercropped with one of two species of forage legumes; Trifolium repens L. or Trifolium pratense L. After the intercropping stage, the cover crop was maintained until the end of winter and then destroyed by plowing before maize was sown. Climatic conditions, and the accumulation of legume and weed biomass were monitored from when the legume was sown to destruction of the cover crop. Our results showed that a minimum threshold of about 500 kg ha−1 biomass in the aboveground parts of the cover crop was needed at the end of intercropping to obtain the minimum biomass of 2000 kg ha−1 in September necessary to guarantee ecological services. To obtain sufficient legume biomass at the end of intercropping period, a thermal time greater than 1900 °Cd and more rainfall than 300 mm are required for legume growth. Moreover, a legume density of at least of 300 plants per square meter at the wheat flowering stage was a good indicator of legume biomass at the end of the intercropping period. Rainfall was a limiting factor of legume growth between the end of the intercropping period and September. Legume density at wheat flowering and climatic conditions during the intercropping period thus appear to be good indicators to predict to capacity of cover crop to produce sufficient biomass in September. These indicators can be used by farmers as a management tool for the cover crop.

The interest of organic farmers in adopting conservation agriculture principles, including minimal soil disturbance, permanent soil cover and crop rotation has been growing since the early 2000s. However, currently there is no network for organic farmers practicing conservation agriculture, and a lack of knowledge on how organic farmers implement conservation agriculture in practice. Consequently, few technical references are available for organic farmers when they start applying conservation agriculture practices, in particular on controlling weeds without the use of herbicides. The main objectives of this study were: (1) to explore the diversity of conservation agriculture techniques (i.e., reduced tillage, no-tillage and green manures) practiced among European farmers, and (2) to identify farmers’ main strategies for implementing conservation agriculture and the agronomic and environmental factors that determine these strategies. Strategies were identified by analyzing survey results on: (1) the type and degree of use of conservation agriculture practices by farmers, and (2) the effects it produces in terms of soil disturbance and soil cover (low, medium and high). We carried out a survey of 159 European organic farmers and collected 125 data sets on management of winter-sown crops. Among the conservation agriculture practices, reduced tillage was used by 89%, no-tillage by 27% and green manure by 74% of the 159 interviewed farmers. Green manures were more frequently used in northern Europe than in the south (below 45°N). Most of the farmers used crop rotations, with a mean duration of 6 years. A wide diversity of conservation agriculture practices were used, with farmers rarely using all three techniques (no-till, reduced till and green manures) within one system. The range of practices was grouped into five strategies ranging from intensive non-inversion tillage without soil cover to very innovative techniques with no-tillage and intercrops. The five strategies for conservation agriculture could be grouped into two larger categories based on weed control approach: (1) intensification of the mechanical work without soil inversion or (2) biological regulation of weeds with cover crops. The diversity of strategies identified in this study shows that organic farmers use innovative approaches to implement conservation agriculture without herbicides. This study's findings will help organic farmers to experiment with innovative practices based on conservation agriculture principles and also benefit conventional farmers who use conservation agriculture practices and would like to reduce or eliminate the use of herbicides.

In organic agriculture, weeds and nitrogen deficiency are the main factors that limit crop production. The use of relay-intercropped forage legumes may be a way of providing ecological services such as weed control, increasing N availability in the cropping system thanks to N fixation, reducing N leaching and supplying nitrogen to the following crop. However, these ecological services can vary considerably depending on the growing conditions. The aim of this study was to identify early indicators to assess these two ecological services, thereby giving farmers time to adjust the management of both the cover crop and of the following crop. Nine field experiments were conducted over a period of three years. In each experiment, winter wheat was grown as sole crop or intercropped with one of two species of forage legumes; Trifolium repens L. or Trifolium pratense L Two levels of fertilization were also tested (0 and 100 kg N ha(-1)). After the intercropping stage, the cover crop was maintained until the end of winter and then destroyed by plowing before maize was sown. Legume and weed biomass, nitrogen content and accumulation were monitored from legume sowing to cover destruction. Our results showed that a minimum threshold of about 2 t ha(-1) biomass in the aboveground parts of the cover crop was needed to decrease weed infestation by 90% in early September and to ensure weed control up to December. The increase in nitrogen in the following maize crop was also correlated with the legume biomass in early September. The gain in nitrogen in maize (the following crop) was correlated with legume biomass in early September, with a minimum gain of 60 kg N ha(-1) as soon as legume biomass reached more than 2 t ha(-1). Legume biomass in early September thus appears to be a good indicator to predict weed control in December as well as the nitrogen released to the following crop. The indicator can be used by farmers as a management tool for both the cover crop and following cash crop. Early estimation of available nitrogen after the destruction of the forage legume can be used to adjust the supply of nitrogen fertilizer to the following crop.

International audience; AbstractReduced tillage is increasingly promoted to improve sustainability and productivity of agricultural systems. Nonetheless, adoption of reduced tillage by organic farmers has been slow due to concerns about nutrient supply, soil structure, and weeds that may limit yields. Here, we compiled the results from both published and unpublished research comparing deep or shallow inversion tillage, with various categories of reduced tillage under organic management. Shallow refers to less than 25 cm. We found that (1) division of reduced tillage practices into different classes with varying degrees of intensity allowed us to assess the trade-offs between reductions in tillage intensity, crop yields, weed incidence, and soil C stocks. (2) Reducing tillage intensity in organic systems reduced crop yields by an average of 7.6 % relative to deep inversion tillage with no significant reduction in yield relative to shallow inversion tillage. (3) Among the different classes of reduced tillage practice, shallow non-inversion tillage resulted in non-significant reductions in yield relative to deep inversion; whereas deep non-inversion tillage resulted in the largest yield reduction, of 11.6 %. (4) Using inversion tillage to only a shallow depth resulted in minimal reductions in yield, of 5.5 %, but significantly higher soil C stocks and better weed control. This finding suggests that this is a good option for organic farmers wanting to improve soil quality while minimizing impacts on yields. (5) Weeds were consistently higher, by about 50 %, when tillage intensity was reduced, although this did not always result in reduced yields.

Conservation agriculture and organic farming are considered as promising sustainable agricultural system for producing food, while minimizing environmental impacts. Despite an increasing number of experimental data on organic conservation practices and various studies dealing with the adoption of conservation agriculture by farmers, none of those studies have specifically addressed conservation agriculture adoption under organic conditions in Europe. We carried out a survey with 159 farmers located in 10 European countries. These farmers had applied at least two of the following conservation practices: (i) no-tillage, (ii) reduced tillage and (iii) green manures. Each farmer assessed socio-economic, agronomic and environmental motivations and problems for each conservation practice, using a Likert scale. For each conservation practice, we ranked motivations and problems and carried out a principal component analysis, followed by clustering to identify groups of farmers. Independent of the conservation practices, the most important motivations were related to soil fertility preservation and challenges were mainly linked to crop management, machinery and yield performances. For all conservation practices, we identify three groups of farmers that shared the same type of motivations and challenges across Europe: “soil conservationists,” “agro-technically challenged farmers,” and “indifferent farmers.” Soil conservationist farmers were strongly motivated by soil preservation and minimizing environmental impacts. Agro-technically challenged farmers mainly expressed agronomic problems and challenges. There were no clear effects of location or farm characteristics explaining these attitudes, but they depended on farmers’ environmental concerns and beliefs. The study demonstrated that research priorities should address agronomic problems caused by the adoption of conservation practices in organic farming, weed control in particular.

International audience; It is a well-established fact that intranuclear-cascade models generally overestimate the cross sections for one-proton removal from heavy, stable nuclei by a high-energy proton beam, but they yield reasonable predictions for one-neutron removal from the same nuclei and for one-nucleon removal from light targets. We use simple shell-model calculations to investigate the reasons for this deficiency. We find that a refined description of the neutron skin and of the energy density in the nuclear surface is crucial for the aforementioned observables, and that neither ingredient is sufficient if taken separately. As a by-product, the predictions for removal of several nucleons are also improved by the refined treatment.

International audience; Many authors have focused on the contribution of inner farm nutrient recycling to closed nutrient cycles, but little is known about the contribution of exchanges among farms to nutrient cycling. By using a network approach, we assessed the structure of farm mass flows networks and their consequences for nitrogen (N), phosphorus (P) and potassium (K) recycling in organic farming at the local scale. Organic farming was considered as a prototype of farming systems that aims at better closing nutrient cycles. Inflows and outflows were collected for two cropping years on 63 organic farms. The farms were located in three French agricultural districts with areas ranging from 520 to 1021 km2 and differentiated by their degree of specialization (specialized in crop production, animal production, or mixed). Local nutrient recycling was assessed at the district scale through: (i) the local supply, defined as the ratio of the amount of nutrients from exchanges among farms plus the amount of nitrogen from atmospheric sources, to the sum of inputs to organic farms; and (ii) the cycling index, defined as the fraction of nutrients flowing at least twice through the same farms. Results showed that exchanges among farms were mainly short-distance exchanges (

It is well known that intranuclear-cascade models generally overestimate the cross sections for one-proton removal from heavy, stable nuclei by a high-energy proton beam, but they yield reasonable predictions for one-neutron removal from the same nuclei and for one-nucleon removal from light targets. We use simple shell-model calculations to investigate the reasons of this deficiency. We find that a correct description of the neutron skin and of the energy density in the nuclear surface is crucial for the aforementioned observables. Neither ingredient is sufficient if taken separately., Presented at the 11th International Spring Seminar on Nuclear Physics. To be published in Journal of Physics: Conference Series

The purpose of this paper is twofold. First, we present the extension of the Li\`ege Intranuclear Cascade model to reactions induced by light ions. Second, we describe the C++ version of the code, which it is physics-wise equivalent to the legacy version, is available in Geant4 and will serve as the basis for all future development of the model. We describe the ideas upon which we built our treatment of nucleus-nucleus reactions and we compare the model predictions against a vast set of heterogeneous experimental data. In spite of the discussed limitations of the intranuclear-cascade scheme, we find that our model yields valid predictions for a number of observables and positions itself as one of the most attractive alternatives available to Geant4 users for the simulation of light-ion-induced reactions., Comment: Submitted to Phys. Rev. C

Organic farmers are interested in soil conservation by reduced tillage, techniques well known in conventional agriculture to protect soil quality and limit labor time and energy costs. However, organic farming and reduced tillage can modify weeds, soil structure, and thus soil nitrogen (N) mineralization which strongly influences wheat yield and quality. The main objectives of this study were to analyze how reduced tillage applied to organic wheat influenced (1) grain yield, protein concentration, and weed infestation; (2) deoxynivalenol (DON) contamination on grain; (3) technological quality parameters such as dry gluten, zeleny index, falling number, and gluten index; (4) protein composition (F1, F2, F3, F4, and F5 fractions, and UPP, gliadin/glutenin ratio); and (5) baking test. For this purpose, we analyzed five site-years of data from winter wheat crops where mouldboard ploughing and reduced tillage were compared in three experimental trials (two in France and one in Switzerland). Main results concern wheat yields: the effect of reduced tillage on wheat yield was influenced by several factors such as weed competition. No significant increase in mycotoxin content (DON) due to reduced tillage was detected. Contamination with DON was always below the European threshold for human consumption. The technological quality parameters were less affected by the tillage treatments than grain yield: protein content, gluten index, zeleny index, and falling number showed on average no significant difference between treatments although the protein composition was slightly different. The main results of this study are that the effect of reduced tillage on grain yield depends very much on soil type, weather conditions, and time after conversion, whereas there is only minor impact on wheat quality. This is in contrast to the hypothesis that reduced tillage under organic farming will cause problems in baking quality.

Nitrogen (N) management is a key issue in livestock-free organic grain systems. Relay intercropping with a legume cover crop can be a useful technique for improving N availability when two cash crops are grown successively. We evaluated the benefits of four relay intercropped legumes (Medicago lupulina, Medicago sativa, Trifolium pratense and Trifolium repens) on N dynamics and their contribution to the associated and subsequent cash crops in six fields of organic farms located in South-East France. None of the relay intercropped legumes affected the N uptake of the associated winter wheat but all significantly increased the N uptake of the succeeding spring crop, either maize or spring wheat. The improvement of the N nutrition of the subsequent maize crop induced a 30 % increase in grain yield. All relay intercropped legumes enriched the soil-plant system in N through symbiotic fixation. From 71 to 96 % of the N contained in the shoots of the legumes in late autumn was derived from the atmosphere (Ndfa) and varied between 38 and 67 kg Ndfa ha(-1). Even if the cover crop is expected to limit N leaching during wintertime, the presence of relay intercropped legumes had no significant effect on N leaching during winter compared to the control.

International audience; The predictive power of the last version INCL4.6 of the Liège Intranuclear Cascade model for spallation is reviewed. The good results obtained both at low and high energy extend the domain of validity of the model and allow the description of spallation reactions, except the coherent processes, by a unique model from a few MeV to a few GeV incident energy.

International audience; A crucial requirement in the development of liquid-metal spallation neutron target is knowledge of the composition and amount of volatile radionuclides that are released from the target during operation. It is also important to know the total amount produced, which could be released if there was an accident. One type is the lead-bismuth eutectic (LBE) target where different radionuclides can be produced following interaction with a high-energy proton beam, notably noble gases (Ar, Kr, Xe isotopes) and other relative volatile isotopes such as Hg and At. The results of an irradiation experiment performed at ISOLDE on a LBE target are compared with predictions from the MCNPX code using the latest developments on the Li'ege Intranuclear Cascade model (INCL4.6) and the CEM03 model. The calculations are able to reproduce the mass distribution of the radioisotopes produced, including the At production, where there is a significant contribution from secondary reactions. Subsequently, a post-irradiation examination of the irradiated target was performed. Investigations of both the tantalum target structure, in particular the beam window, and the leadbismuth eutectic were performed using several experimental techniques. No sign of severe irradiation damage, previously observed in other ISOLDE targets, was found.

International audience; Organic farming systems are often nutrient-limited. Moreover, even if organic guidelines emphasize the reliance on ecological processes and recycling, the trend towards farm specialisation induces an increased reliance on off-farm fertilising materials in arable areas. There is, therefore, a need to better understand the drivers of nutrient inflows on organic farms. Our objectives were to assess the nitrogen (N,) phosphorus (P) and potassium (K) farm-gate inflows through fertilising materials, and the nutrient budget and use efficiency over a large range of organic farming systems. To do this, 56 interviews with organic farmers concerning their nutrient management for the years 2010 and 2011 were carried out in 2012 in three French agricultural districts distributed over a gradient of farming activity. The results showed that the farm-gate fertilising material inflows were strongly related to both the ratio of land under cereal and oilseed crops (proxy of nutrient ‘demand’) and the stocking rate (proxy of nutrient ‘supply’). However, other inflows (biological N fixation, feed use, fodders and straws) increased with the stocking rate, leading to low farm-gate N and K use efficiency (0.2 and 0.7, respectively) on livestock farms compared to arable, stockless farms (1.4 and 3.5, respectively). Such results helped to disentangle the drivers of nutrient use in organic farms compared to previous analyses based solely on farm production typology.

ESSN: 1879-4246; International audience; Organic agriculture is a production system which relies on ecosystem management and ecological processes rather than on the external flow of agricultural inputs. The development of the organic sector has incluced a spatial decoupling of livestock and crop production. This has increased the flow of nutrients that occurs between farms compared to what happens within individual farms. Organic systems have replaced synthetic inputs with site-specific management practices to balance input and output nutrients to ensure short-term productivity and long-term sustainability. This paper addresses the nutrient management of mixed and specialized farming systems, with a special emphasis on the reliance on livestock production for the nutrient management of arable farmland. We assessed the nutrient budgets of nitrogen (N), phosphorus (P), and potassium (K) of 28 organic farms selected according to livestock density from three French countries. The farms were classified as stockless, mixed, and cattle farming systems. A soil surface nutrient budget was calculated for each farm based on inputs (N fixation, excreta, and manure) and outputs (grazing, offtake, harvests) on annual crops and grasslands. Inputs due to N atmospheric deposition and seeds and losses due to leaching and volatization were not considered in this study. Nutrient budgets of the 28 farms revealed N, P and K deficits, although disparities between farming systems and their geographical location were also observed. Stockless farms presented high N deficit whereas mixed and livestock farming systems presented lower deficits (close to equilibrium) or even surpluses in a county with a high density of livestock farms. Differences between farming systems in terms of P and K budgets followed the same trend, but regional specificities appreared significant in stockless and livestock systems (related to the size of farms and the stocking rate). None of the farms purchased off-farm organic fertilizers when exchanges of manures and straw were observed at the regional scale. When livestock is present on the farm, the nutrient resources came mainly from recycling internal resources (manures, excreta, and N fixation), whereas stockless farming systems purchased organic manure from neighboring farms ( 14 to 58 % of total N inputs, 10 to 100 % of total P and K inputs). The sustainability of stockless organic farming systems is questioned, noticeably those that were located in regions where resources of organic matter are scarce. Only farming systems producing large quantities of manure or which purchased feed showed balanced nutrient budgets.

In organic grain production, weeds are one of the major limiting factors along with crop nitrogen deficiency. Relay intercropping of forage legume cover crops in an established winter cereal crop might be a viable option but is still not well documented, especially under organic conditions. Four species of forage legumes (Medicago lupulina, Medicago sativa, Trifolium pratense and Trifolium repens) were undersown in six organic wheat fields. The density and aerial dry matter of wheat, relay-intercropped legumes and weeds were monitored during wheat-legume relay intercropping and after wheat harvest until late autumn, before the ploughing of cover crops. Our results showed a large diversity of aerial growth of weeds depending on soil, climate and wheat development. The dynamics of the legume cover crops were highly different between species and cropping periods (during relay intercropping and after wheat harvest). For instance, T. repens was two times less developed than the other species during relay intercropping while obtaining the highest aerial dry matter in late autumn. During the relay intercropping period, forage legume cover crops were only efficient in controlling weed density in comparison with wheat sole crop. The control of the aerial dry matter of weeds at the end of the relay intercropping period was better explained considering both legumes and wheat biomasses instead of legumes alone. In late autumn, 24 weeks after wheat harvest, weed biomass was largely reduced by the cover crops. Weed density and biomass reductions were correlated with cover crop biomass at wheat harvest and in late autumn. The presence of a cover crop also exhibited another positive effect by decreasing the density of spring-germinating annual weeds during the relay intercropping period. (C) 2013 Elsevier B.V. All rights reserved.

Wheat yields and grain protein content are lower and more variable in organic conditions than in conventional agriculture, mainly due to nitrogen (N) deficiency and weed competition. The undersowing of legume cover crops in growing winter wheat, also known as relay intercropping, is assumed to be a proficient way of enriching the soil-crop system with N and improving weed control. However, competition for resources may impair wheat performance. Relay intercropping in springtime in growing winter wheat is expected to limit competition for resources from the legume. The aim of our study was to analyze wheat performance and resource competition in relay intercropping systems with legume cover crops under various environmental conditions. Eight field experiments were conducted on organic grain-oriented farms located in southeast France. Black medic (Medicago lupulina), alfalfa (Medicago sativa), red clover (Trifolium pratense) and white clover (Trifolium repens), undersown at wheat tillering stage, were compared with a sole crop of winter wheat (Triticum aestivum cv. Lona). The aerial biomass of wheat and legumes and total N content of wheat were determined at both the flowering stage and harvest time of the wheat. The main trophic resources (water, N and light) were monitored at similar stages. Wheat grain yield and grain protein content were also measured. Sites were classified according to wheat sole crop performance at harvest to evaluate the effect of relay intercropping in the various conditions tested. In all but one of the thirty-two treatments, wheat grain yield was not significantly disturbed by relay intercropping whatever the aerial development of legumes. Abundant aerial development of legumes after flowering (>20% of the aerial biomass of wheat at harvest) was associated with a mean significant decrease in wheat grain protein content of 8.5% of the control treatment value, this occurring in one third of the situations. These ratios of aerial biomasses of legumes compared to wheat were also associated with reductions in soil moisture and wheat N uptake. The effect on the availability of trophic resources for wheat may have led to a decrease in grain protein content without having any effect on grain yield. Sites which registered a low performance for wheat sole crops were less negatively impacted by the presence and aerial development of legumes. The performance of the four legume species and the mechanisms of induced disturbance of resource availability are then discussed. Finally, we try to define ranges of legumes' development and resource availability in which wheat performance was maintained or limited. (C) 2013 Elsevier B.V. All rights reserved.

International audience; Liquid lead-bismuth eutectic (LBE) is often considered as a possible target in spallation neutron sources. Anexperiment has been performed in 2005 at ISOLDE (CERN), in which LBE has been irradiated by 1.0 and 1.4GeV protons and isotopes of astatine, a volatile precursor of Po, have been found. Until recently no modelwas able to reproduce this astatine production, which is due either to double charge exchange reactions,Bi(p,π-xn)At, or to secondary reactions induced by helium nuclei. Recently, both parts of the spallation modelcombination INCL4-Abla have been improved leading to the new versions, INCL4.6-ABLA07. In particular,an additional mechanism to produce light and intermediate mass fragments has been added and special carehas been paid to the low energy reactions. This paper first shows that all the basic features of the differentreactions leading to astatine production are well predicted by the new model. The model, implemented into abeta version of MCNPX2.7 is then used to simulate the ISOLDE experiment. A very good agreement with theexperimental data is observed.

International audience; In the framework of the European Spallation Source (ESS) project, works on ESS target design needcomputational tools and the validation of these tools must be done to estimate accuracy of the calculationresults. INCL4.6 and Abla07 have been implemented in a beta version of MCNPX2.7 to be able to use themwhen transport is needed as ESS spallation target design. Within ESS project, we decided to benchmark ourspallation model on excitation functions (p+W) to assess the reliability on a thin target according to theproduced isotope and the projectile energy. We focused on a list of hazardous nuclei given by previous ESScalculations and from previous experiments. These results, which can of course help to estimate uncertaintiesas designing ESS target, were supplemented by another benchmark done with a thick tungsten target andgiving isotope production along the beam axis and radially as well.

We use the tools of hybrid intranuclear-cascade/nuclear-de-excitation models to evaluate the sensitivity of several physical observables to the inclusion of a multifragmentation stage in the deexcitation chain and assess the need for a multifragmentation model in the quantitative description of p + 56 Fe and p + 136 Xe reactions at 1-GeV incident energy. We seek clear signatures of multifragmentation by comparing different state-of-the-art de-excitation models coupled with intranuclear-cascade models and by focusing on discriminating observables such as correlations and fragment longitudinal-velocity distributions. None of the considered observables can be unambiguously interpreted as a multifragmentation footprint. The experimental data are best described as originating from sequential binary decays. However, no de-excitation model can reproduce the experimental longitudinal-volocity distributions from 1-GeV p + 136 Xe.

This chapter is a first attempt to analyse bottlenecks and challenges of European organic bread wheat sector involving technical, political and market issues. From 2000, the organic grain market has largely increased in Western Europe. To balance higher consumer demand there is a need to increase organic production by a new transition and technical improvement. Bread wheat is grown in a variety of crop rotations and farming systems where four basic organic crop production systems have been defined. Weeds and nitrogen deficiency are considered to be the most serious threat inducing lowest grain yield under organic production. The choice of cultivar, green manure, fertilization and intercropping legumes – grain or forage – are efficient ways to obtain high grain quality and quantity. The economic viability of wheat production in Europe is also affected by subsidies from European Union agri-environmental programs. Support has been granted to organic farming since the beginning of the 1990s. Direct payments from European regulation combined with premium prices paid by consumers had compensated the lowest crop production. In the European Union, the current cycle of the Common Agricultural Policy (CAP) is due to end in 2013. Discussions are now under way to support the policy for the period 2014–2020. With the increasing consumer awareness of their food, the growth of the organic sector may continue in the near future. However, financial crisis in some countries may lead to stagnation or even decline of consumer demand. The development of the organic grain sector is actually confronted to others challenges as quality and safety value. Technological ways of milling and baking may also improve baking quality and nutritional value of organic flour, as well as it prevents mycotoxin contamination. For instance, milling process strongly influences flour characteristics. Stone milling improves nutritive value when characteristics remain very stable independently of the milling yield while flour characteristics from roller milling appear very susceptible to the milling yield. The economic efficiency of the bread wheat sector is also influences by the existence of an adequate marketing structure answering consumers’ requirements. This paper is a contribution of a multidisciplinary group of researchers involved in AGTEC-Org project using peer review, statistical data and interviews of key actors: farmers, advisers or experts (coreorganic.org/research/projects/agtec-org/index.html).