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Towards a Digital Twin of Tomato - A modular, ontology-based tomato FSPM
No full textInternational audienceThis study presents a new FSPM of tomato in a semi-closed greenhouse production system, which has been conceived based on the comparison of published photosynthesis models (mainly of tomato, plus some other crops), their scale of application, their input and output parameters, thereby leading to the proposition of an ontology for this production system, with the hope that it can become sufficiently generic to be applied to other crops. The long-term objective of this study is to combine the different models as modules to create an ontology-based Digital Twin of a semi-closed greenhouse tomato production system
Disentangling the influence of density dependence, size dependence and environmental effects on fish population dynamics
No full textData were provided by SIH—Système d'Informations Halieutiques. In compliance with articles R 921-76 and R 921-82 of the Code Rural et de la Pêche, the Direction Interrégionale de la Mer authorized data collection during PELGAS surveys. No specific ethics approval was required for those surveys.International audienceImproving our understanding of the ecological and demographic mechanisms that underlie changes in wild population productivity is critical to support ecosystem‐based management. Yet, population productivity results from a combination of demographic rates (such as mortality, growth and recruitment) driven by intrinsic and extrinsic factors which interact through density‐, size‐ or environment‐dependent mechanisms. The interdependence between demographic rates, and intrinsic and extrinsic factors, has rarely been studied throughout the life cycle of a wild population. This is particularly needed for short life species, such as small pelagic fish, which are subject to inter‐annual abrupt changes in abundances. Here, we developed an age‐based life‐cycle model to investigate the relative influence of intrinsic and extrinsic factors on successive transitions rates along the life cycle of a system composed of two small pelagic species of the Bay of Biscay, the European anchovy ( Engraulis encrasicolus ) and European sardine ( Sardina pilchardus ). Our model allows to disentangle the influence of density dependence, size dependence and environmental factors throughout the life cycle of short life species. Our results highlight that sardine demography is density‐dependent, with significant effects of density on natural mortality at age 1 and age 3. In contrast, anchovy demography is both size‐ and density‐dependent, with density‐dependent effects on natural mortality at age 1, age 2 and on recruitment, and a size‐dependent effect on age‐1 mortality. Moreover, we found that natural mortalities of both anchovy and sardine were related to large‐scale environmental indicators, such as the Atlantic Multidecadal Oscillation and the North Atlantic Oscillation. The originality of this approach lies in its ability to integrate the effects of size, density and environment on a multitude of demographic processes throughout the life cycle for wild species, and can be seen as a step towards supporting ecosystem‐based management
One size does not fit all : from a theoretical monolithic livestock future to anchored levers for agroecological transitions in a diversity of landscapes
No full textSession 52 - Théâtre 1International audienceLivestock farming generates high environmental impacts at a global scale, what is calling for a major change. Circular economy approaches call for recycling nutrients, optimizing feed production and incorporating innovative practices. Such general assumptions are related to a theoretical monolithic vision of livestock, whereas livestock systems are as diverse as the territories where they are anchored, thus providing a diversity of services and impacts.Here, we aim at enlightening the debate illustrating livestock agroecological transition forms in the lens of a diversity of landscapes. For this, we combine landscape agronomy and transitions studies frameworks considering both i) the central role of farmer motivations, practices and biotechnical aspects in a landscape approach and ii) the socio-technical systems including actor networks and the broader market and policy factors over the long term. We explore a diversity of landscapes from high density livestock areas (Brittany) to low density livestock areas (Parisian Bassin and South-Eastern France) passing by areas were crop and livestock are balanced and infrastructures and knowledge still exist (South-Western France). This transversal analysis led us to conclude on the need for livestock agroecological transition studies to consider jointly i) the looping of geochemical cycles through crop-livestock interactions not only at farm level, but also at regional level, considering the need for down-scaling models and ii) the importance of the local ecosystem of innovation and the motivations for changeof a large diversity of actors beyond farmers. Environmental stewardship could be key through mechanisms such as rural development, including coupled innovations with food, tourism and cultural services, and managing commons for limiting the risk of wildfires or water pollution
Climate, Cities and Societies : the French Urban Climatology Network
No full textInternational audienceThe urban climatology community has been structured internationally at different levels for several years with venues such as ICUC, AGU, EGU or IC2UHI which regularly bring together different members of academia addressing urban climate-related research and engineering challenges from different disciplines, countries and perspectives. Late 2018, a series of meetings of the French community were launched. Two in-person meetings occurring in Paris, France in early and late 2019, bringing together 30-40 academics from different French research groups and universities across the country.During the COVID-19 pandemic and lockdown episodes, networking and research sharing took place in the form of a series of online webinars in 2021 offered a venue for young researchers to present their work to their peers and research community. In-person meetings took place once again starting in 2022. Building on the community’s engagement and interest, the research network began formalizing its existence and organization, currently structured into four thematic groups focused on:numerical modelingfield observationsknowledge transfer for operational applicationsteaching and public dissemination of scientific and technical informationThe community currently comprises around 150 members from 50+ different research institutes, as well as the public (government agencies), private (startups and SMEs) and local government (municipalities, urban planning agencies, …) sectors. These members are involved in work spanning a wide range of disciplines from the technical, natural and human and social sciences and conducted at a variety of spatial scales ranging from urban materials to the regional scale (“nano”, “indoor”, micro, local and meso-scale climates) and focusing on the study of urban climate: from fundamental science to climate change adaptation solutions.The proposed contribution will present the network, its membership as well as work undertaken by its thematic groups, including a literature review of radiation shields
Combining technical and social localized knowledge to support the co-design of integrated crop-livestock systems between farms
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International trade in agricultural commodities and water use in agriculture: The case of Tunisia
No full textInternational audienceThe article investigates the link between agricultural trade and the use of irrigation water in Tunisia. We build a database that matches region-level information on country’s agricultural production, water footprint, and trade. We highlight the heterogeneity of Tunisian governorates in terms of crop specialization, and of irrigation water footprint of their agricultural production and exports. Our results reveal that most governorates export a larger fraction of their irrigation water than of their agricultural production. Olives and dates, flagship products of Tunisia’s agriculture, account for the vast majority of the virtual water "hidden" in the exports of primary or processed agricultural products. In contrast, the irrigation water productivity of these products is not very high. We estimate this productivity at USD 1/m³ for the exports of dates and at USD 2-3/m³ for the exports of olives and olive oil. Citrus fruits, tomatoes, and cereals, which are cultivated with a major input in rainfall, feature a productivity of irrigation water up to ten times higher. However, most of them are consumed domestically because Tunisia is less competitive in these products on international markets
Dirichlet Process Mixture Model and Markov Random Field for PolSAR Image Segmentation
No full textInternational audienceThe Dirichlet Process Mixture Model (DPMM) is a Bayesian nonparametric approach commonly used in unsupervised learning, notable for its ability to infer the number of components in the data. In this work, DPMM is integrated with a Markov Random Field (MRF) to tackle the segmentation of Polarimetric Synthetic Aperture Radar (PolSAR) images. The MRF incorporates spatial context, enhancing segmentation accuracy. Class labels are updated using the Expectation Maximization algorithm. The proposed EM-DPMM-MRF model is evaluated on both simulated and real PolSAR images with known ground truth. The experimental results demonstrate strong and consistent performance
Miniaturization of the fouling of whey proteins in falling film evaporators by microfluidics
No full textInternational audienceFouling remains an unsolved challenge in the dairy industry, affecting operational efficiency and product quality. While extensive research has focused on fouling dynamics in heat exchangers, falling-film evaporators (FFE) have received less attention. There is scientific consensus that heat-induced protein denaturation is the main reason for fouling development, neglecting other potential mechanisms especially at relatively low temperatures.In a recent study [1], we demonstrated that increasing shear rates foster the formation of whey protein deposits and enhance their structural complexity even at temperatures below the denaturation one. While highlighting the role of shear rate, this work does not shed light on the surface and bulk mechanisms leading to deposit formation.In this context, we characterized in real-time the stages of dairy fouling development using microfluidic devices simulating FFE conditions. We aimed at discriminating the effects of shear (0-200 s-1) and temperature (50-75 °C) on the kinetics of deposit growth during the flow of whey protein solutions (10 wt. %). The key findings of this analysis can be summarized in two points:1. At low (50 °C) and high temperatures (75 °C), no deposit formation and fast channel clogging are observed, respectively, thus underlining the strong influence of heat-induced protein denaturation.2. At intermediate temperatures (65 °C), shear is a limiting factor controlling the accumulation of solids at the surface.These results provide a new insight on fouling mechanisms at the micron-scale and underline the coupled effect of shear and temperature under the typical FFE operational range of temperature
Inter-quarter variability of milk β-hydroxybutyrate content in dairy cows
No full textInternational audienceMilk β-hydroxybutyrate content (BHB) is commonly used to diagnose the risk of ketosis in dairy cows. The results of a recent study suggest the existence of a within-udder variability in milk BHB contents between quarters. So we aimed to study BHB inter-quarter variability in dairy cows in early lactation by comparing it to other milk components and to blood BHB. The analyzed data are from a previous experiment carried out on 13 commercial dairy farms in Quebec (CA) and performed on multiparous cows at wk 2 and 3 of lactation. The dataset consisted of 5,072 cisternal milk samples from each of the four quarters of 726 cows. Cows were sampled once or twice (n= 184 and 542, respectively). Blood BHB analysis were assessed on the same day and time, immediately after collection. Cows were classified for blood BHB as blood BHB- (<1.2 mmol/L) or blood BHB+ (≥1.2 mmol/L) and classified according to their number of quarters with elevated BHB (≥ 0.15 mmol/L) : 0Q, 1Q, 2Q, 3Q, 4Q. Milk BHB averaged 0.14 mmol/L (SD = 0.11, min = 0, max = 2.12 mmol/L). The coefficients of variation (CV) for milk components were calculated by dividing the SD of the four udder quarters of a cow by the mean of those four quarters. The highest mean of CV was that of SCC, at 77%, followed by milk BHB content (20%), milk fat and urea content (18%), and milk protein and lactose content (2.6%). Out of 726 cows, 176 were categorized blood BHB+ once and 109 cows twice. The majority of cows (58%) with blood BHB- presented no udder quarters (0Q) with elevated milk BHB. 14, 7, 8, and 13% of blood BHB- cows had, respectively, 1Q, 2Q, 3Q, and 4Q with milk BHB above 0.15 mmol/L. In cases of blood BHB+ cows, the majority of cows (74%) exhibited elevated milk BHB either in all four quarters (4Q) (46%) or in none (0Q) (29%) whatever the DIM. In conclusion, this study reveals inter-quarter variability of milk BHB levels underscoring the importance of accounting for this variability and its causes when using milk-based diagnostics
Exploring the Water Rebound Effect: Policy Interactions in Tunisia’s Agricultural Sector
No full textInternational audienceTunisia faces increasing water scarcity, shaped in part by a historically supply-driven water mobilization strategy that has prioritized large-scale infrastructure projects—such as dams and groundwater extraction—to support agricultural expansion and export-oriented production. Since the 1990s, the country has introduced a range of economic instruments intended to promote more sustainable water use, including subsidies for efficient irrigation technologies and pricing mechanisms. Over the same period, public investment in the agricultural and water sectors has steadily increased, alongside a continued rise in water extraction, particularly for irrigation.To better understand the dynamics behind these trends, this study explores the Water Rebound Effect (WRE) in Tunisia using a consumer theory framework, drawing on concepts such as substitution and income effects to interpret producers’ adoption of irrigation technologies. This theoretical perspective is complemented by a historical review of Tunisia’s water governance as well as its agricultural and trade policy instruments, with a focus on their alignment with sustainable water resource management, including key legislation such as the 1975 Water Code and the 1993 Investment Code.In this context, we aim to examine whether the trajectory of agricultural intensification and water use in Tunisia since 1990 may reflect rebound effect mechanisms, particularly in relation to policies promoting efficient irrigation technologies