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Microbiome metabolic modeling as a tool for innovation in fermented foods
No full textInternational audienceAt the crossroads of a growing interest in fermented foods as part of a healthy, sustainable diet and advances in multi-omics technologies stands the need for developing new types of fermented foods while improving traditional ones. The scientific path toward these challenges lies in our capacity to rationalize and predict microbial interactions. For this, genome or metagenome-scale metabolic modeling represents a promising approach. We assess its benefits and limits through rare examples in the field of food microbiomes and advocate for community-level metabolic engineering as the superior strategy. We underline their power as a cornerstone in comprehensive and rational strategies for optimization of microbial consortia assembly, whether they are used in bottom-up or top-down approaches. We raise the challenges and bottlenecks of integrating the dynamics of microbial communities and present how we foresee their potential for shaping the future of fermented foods and regulatory science, bridging gaps between knowledge and innovation
Relations entre ruralité et biodiversité. Le succès de la patrimonialisation en commun de la plaine de Versaillespour une meilleure protection de sa biodiversité
No full textInternational audienc
High-frequency fluorescence monitoring in karst aquifers: A multivariate approach for early detection of anthropogenic contamination of water resources
No full textInternational audienceKarst aquifers play an essential role in drinking water supply, but their vulnerability to anthropogenic pollution, particularly during rainfall events, requires adapted monitoring methods. In this study, we developed an approach combining high-frequency in situ measurements and laboratory analyses to characterise the intensity and occurrence of organic matter fluorescence peaks, in particular Tryptophan-Like Fluorescence (TLF) peaks, associated with faecal contamination. We adapted a background noise correction method based on multiple regression applied to multispectral signals from field fluorometers. A specific calibration in TLF equivalents of the signals from an optical sensor measuring fluorescence at 285 nm is used to quantify contamination peaks. This method was tested on a dataset including 95 samples analysed in the laboratory and high-frequency data spanning 2015–2025 at 15-minute intervals from the Lez karst spring (France), showing its effectiveness in correcting optical interferences and detecting low pollution episodes. The analysis of time series underlined the importance of high-frequency monitoring to capture rapid water flow dynamics, while confirming the indispensable complementarity of laboratory analyses to better discriminate the fluorophores controlling the intensity of high-frequency in situ signals. The results highlight critical contamination periods, particularly in autumn and spring, and confirms the suitability of TLF for Early Warning System (EWS) applications. This approach broadens the methods used for water quality management in karst environments and proposes a methodological framework transferable to other sites
Modeling breeding programs considering social behavior in large groups of farmed fish
No full textBreeding programs are essential in aquaculture, improving economically and environmentally important traits. In aquaculture systems, animals are raised in large groups, where social interactions are frequent and can influence individual performance. In these circumstances, indirect genetic effects can play an important role in the response to selection, and consequently, their effects on selection outcomes must be analyzed.This study aimed to evaluate the implications of heterogeneous social interaction effects on fish breeding programs using stochastic simulations. We simulated a fish breeding program with 2000 selection candidates from 1000 families formed by a partial mating design of 100 males and 100 females. Social interactions were simulated, affected by the target phenotype and two latent-personality traits. We investigated how genetic gains and phenotypic variances are affected by the magnitude and direction of social interaction effects on the target phenotype, different selection strategies, and the genetic correlations between the target phenotype and personality traits. Our results showed that increased social interaction effects lead to greater phenotypic variability in the target trait. Under mass selection, the genetic means of personality traits change, and these changes depend on the strength and direction of genetic correlations between the focal and personality traits. Conversely, group selection did not increase phenotypic variability but reduced genetic gain for the focal trait compared to mass selection. Moreover, group selection did not alter the genetic means of personality traits. However, this approach increased the rate of inbreeding per generation, which could be mitigated by optimizing the number of families per group..</div
Problèmes d'affectation dans les réseaux de fonctions de coût
No full textInternational audienceTo efficiently solve exact discrete optimization problems, branch and bound algorithms require tight bounds. In constraint programming, for optimization, soft arc consistencies typically derive much stronger bounds than those offered by domain or bound consistencies applied to a cost variable. The reason is that soft local consistencies exchange marginal cost information between variables whereas domain consistencies rely only on shrinking domains, which is less informative. However, CP solvers equipped with soft arc consistencies have so far offered limited support for efficient processing of global constraints. In this work, we show how we can efficiently enforce soft local consistency over the ALLDIFFERENT constraint, relying on algorithms for the Linear Assignment Problem (LAP). We implement this propagator in toulbar2, the state-of-theart weighted CP solver exploiting soft local consistencies for bounding. On problems that include ALLDIFFERENT constraints, we show that, equipped with this new propagator, toulbar2 outperforms state-of-the-art domain consistencybased CP as well as integer programming solvers for the Quadratic Assignment Problem and shows better performance for miniCOP instances of the 2024 XCSP competition with ALLDIFFERENT constraints.</div
: Ce que la science du climat dit — et ce que nous faisons déjà
No full textAllocation prononcée à l’occasion de l’Assemblée Générale de l'AMAP de Bagneux (92)Ce texte ne vise ni à convaincre par l’alarme, ni à prescrire des comportements, mais à mettre en regard ce que dit la science du climat et ce que les AMAPiens pratiquent déjà collectivement. Il est écrit à la fois en tant que chercheur et en tant que membre engagé dans le maintien d’une agriculture paysanne locale
A Soil–Plant–Atmosphere Continuum model coupled to CFD to simulate plant energy and water exchanges in heterogeneous microclimates
No full textInternational audienceEstimating plant growth conditions in agrivoltaic, agroforestry, or urban environments are applied examples exhibiting the need to consider the intricate relationships between spatially heterogeneous microclimate conditions (short-wave and long-wave radiation, wind, turbulence, and air temperature), plant and soil energy balances with air and water exchanges. To capture these connections, the Soil–Plant–Atmosphere Continuum model from A. Tuzet has been implemented in the computational fluid dynamics software code_saturne, which simulates spatially heterogeneous and time-varying fluid flows, along with short-wave and long-wave radiation. This coupling is compared to experimental measurements from two French sites of the Integrated Carbon Observatory System (ICOS). Our model achieves significant outcomes in assessing energy exchanges, maintaining a relative error of less than 20% compared to ICOS measurements. In addition to accurately reproducing variations of latent and sensible heat fluxes due to radiation, the coupling of the water balance and stomatal conductance models demonstrates its capability to predict the evolution of soil water content over several days. Finally, an extrapolative study of fictive environments with plants beneath obstacles reveals promising opportunities to understand how obstacle-induced shadows and wakes affect plant temperature. This leads the way for further research in agrivoltaic, agroforestry, or urban configurations with spatial scales from approximatively 10m2 up to 1000m2 and temporal scales ranging from single moments to several consecutive days
Settling on their ground: The shifting land politics of armed actors in the urban margins of Medellín
No full textInternational audienceHow do armed groups shape land orders in the urban margins? While the power dynamics of non-state armed actors over land resources have been extensively studied in rural contexts, urban settings have received far less attention. In response to the growing influence of criminal organizations in the informal land markets of Latin American cities, this article offers a historical perspective on the involvement of armed actors in Medellín’s political economy of urban land. From guerrilla movements in the 1970s to contemporary criminal gangs, we trace how different groups have exercised land control in informal settlements. Building on this historical perspective, we argue that, while control over land access has long been a tool of territorialization for non-state armed actors, the contemporary criminal land market reflects a shift compared to earlier periods, as these actors seek to monopolize land control and extend their regulatory power over local populations
Le stockage en super-réfrigération réduit la croissance et la diversité des communautés bactériennes associées aux filets de saumon de l’Atlantique (Salmo salar)
No full textThe data were shared. Raw reads have been deposited in the Sequence Read Archive (SRA) under the project accession number PRJNA1233232.International audienceSuperchilling is an innovative preservation technique that maintains food products at temperatures between conventional refrigeration and freezing. It addresses the challenge of minimizing food spoilage while enhancing process sustainability. In this study, the evolution of the bacterial ecosystem of fresh salmon fillets was investigated under two superchilling temperatures (–1.8 °C and –2.8 °C) and compared with conventional refrigeration at 2 °C and storage at the initial freezing point (–0.8 °C). Total viable counts were monitored over a 20-day storage period using Plate Count Agar (PCA), and bacterial community diversity was assessed at day 0 and after 20 days of storage using 16S rRNA gene metabarcoding. Although superchilling did not fully inhibit bacterial growth, it effectively slowed microbial proliferation compared with refrigeration, thereby significantly extending microbiological shelf life. Bacterial community composition changed markedly after 20 days of cold storage, with subzero storage temperatures being more strongly associated with reduced microbial diversity. Pseudomonas became dominant under all conditions, particularly under superchilling (reaching up to 90.6%), followed by Photobacterium, which declined to the second position, and Brochothrix which was not detected at day 0. Cold temperatures strongly influenced microbial ecosystems, with superchilling promoting the development of more homogeneous communities. Overall, this study demonstrates the decisive influence of storage temperature on microbial community composition and provides a basis for selecting complementary approaches to optimize the industrial application of superchilling
Climate shocks and banking sector stability: Evidence from El Niño southern oscillation
No full textInternational audienceThis study introduces a novel ex ante approach to assess the short-term impact of climate shocks on banking sector stability by examining the effect of El Niño Southern Oscillation (ENSO) on banking sector distance-to-default. Using dynamic panel data econometric modeling, we investigate the macroeconomic implications of ENSO-induced climate shocks, such as El Niño and La Niña events, on banking sector stability in 51 countries across three regions particularly exposed to the consequences of ENSO oscillations (East Asia and Pacific, Latin America and the Caribbean, and Sub-Saharan Africa) during the period 2000–2020. Our findings show that the adverse effects of these climate shocks on banking sector stability are unevenly distributed among countries, with more pronounced and robust adverse effects of El Niño events in the short-term, particularly in Latin America and the Caribbean and, to a lesser extent, Sub-Saharan Africa. We also document the short-term adverse effects of La Niña events for Latin American and the Caribbean countries. Further estimates suggest that the increase in non-performing loans is a key transmission channel linking El Niño events to banking sector stability. As global warming should intensify the frequency and magnitude of ENSO's cyclical pattern, these findings can help estimate the potential adverse effects of climate change-related natural disasters on banking sector stability and inform future mitigation and adaptation policies