Portail HAL Um (Université de Montpellier)
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CSRR-based resonator for complex dielectric permittivity measurements up to 35 GHz
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A safari across France: soil fauna insights from a nationwide soil quality monitoring program
No full textInternational audienceSoil biodiversity is fundamental to ecosystem functioning but remains underrepresented in conservation policies and large-scale monitoring. Here, we present RMQS-Biodiversity, a nationwide soil biodiversity survey integrated into the French Soil Quality Monitoring Network (RMQS), and illustrate its potential for soil ecology research. In this pioneer study, we examine three major ecological aspects: (i) how systematic grid-based sampling captures micro-food web patterns using nematode communities, (ii) the spatial turnover of detritivore communities (Collembola, Isopoda, Diplopoda) in response to environmental and geographic gradients, and (iii) the influence of macroecological drivers on predator (Carabidae) morphological traits. Across 69 sites, we identified a few widespread species coexisting with numerous rare taxa, underscoring the value of large-scale surveys for detecting cryptic biodiversity. Nematode indicators revealed high variability in food web structure across land uses, with increased facultative phytophagous nematodes in forests. Isopods and diplopods were strongly structured by dispersal constraints, while springtails exhibited weaker environmental responses, likely due to their higher dispersal capacity. Additionally, sexual size dimorphism in Carabidae varied by habitat, with female-biased dimorphism in closed habitats but no dimorphism in open environments, highlighting habitat stability's role in shaping morphological traits. This study demonstrates the value of multi-taxon, multi-trophic biodiversity assessments in long-term soil monitoring. RMQS-Biodiversity provides a robust framework for soil biodiversity monitoring and conservation, refining bioindicators of soil quality and informing policies such as the EU Soil Monitoring Law
Culturable macroplastic-associated potential human pathogens in coral reef lagoons, Madagascar
No full textInternational audiencePotentially human pathogenic bacteria (PHPBs) have been detected in plastic-associated marine microbiomes, primarily through DNA-based methods. However, data on their culturability and concentrations on plastics remain limited, yet are essential to assess actual health risks. To address this gap, 70 floating macroplastic and 20 seawater samples were collected from two human-impacted reef lagoons in southwestern Madagascar (AtsimoAndrefana region). PHPBs were cultured from their microbiomes using selective media and quantified. Macroplastics were predominantly polypropylene (34 %) and polyamide (31 %). In increasing order of concentration, four culturable PHPBs, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Vibrio Harveyi clade species, were identified on both macroplastics and in seawater, across all sites and polymer types. Notably, 52 % of macroplastic samples harbored two PHPB species simultaneously, while only 7 % were PHPB-free. Concentrations of all PHPBs were consistently and significantly higher on macroplastics than in seawater, regardless of the measurement unit or polymer type, with the Vibrio Harveyi clade being the most abundant. No significant correlations were observed among PHPB species concentrations, suggesting limited interaction and independent colonization. These findings indicate that floating macroplastics may serve as reservoirs and fomites for viable PHPBs. However, their potential impacts on ecosystems and human health should be interpreted cautiously. We emphasize the need to contextualize PHPB concentration data by considering factors such as exposure pathways, environmental persistence, and bacterial virulence, rather than relying solely on concentration-based comparisons, which may lead to misinterpretatio
Share the ride: The determinants of long-distance carpooling pricing strategies in France
No full textInternational audienceThis paper investigates the pricing strategies used in long-distance carpooling in France. We investigate how several factors affect carpooling prices using a comprehensive dataset of BlaBlaCar trips combined with sociodemographic and intermodal competition data. The analysis identifies two distinct pricing patterns within the platform: one characterized by standardized and consistent pricing, and another marked by more flexible, market-responsive price setting. By focusing on price per minute, we examine how trip characteristics, competitive conditions, and demand heterogeneity affect these pricing behaviors. The results show that variables such as the number of stopovers, trip length, airport or cross-border connections, and the presence of alternative transport modes influence pricing, but with contrasting effects across the two patterns. The standardized approach tends to reflect cost-sharing principles and reinforces network effects, while the more flexible approach adapts dynamically to local competition and demand
Harnessing the potential of medicinal plants in the malaria fighting: In vitro and in vivo antiplasmodial activities of Feretia apodanthera Delille (Rubiaceae)
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Flash vacuum expansion technology for small-scale production of fruit puree: development and quality assessment
No full textInternational audienceFruit processing at small scale often lacks access to efficient, integrated technologies capable of ensuring product quality and safety. Flash Vacuum Expansion emerges as a promising alternative to conventional thermal treatments by coupling rapid steam heating with instant decompression, enabling simultaneous pasteurization and cooling, tissue disintegration, and deaeration. This study presents the design, construction, and validation of an optimized Flash Vacuum Expansion prototype tailored for small- and medium-scale agroindustries. The system integrates six unit operations—blanching, pasteurization, mashing, cooling, deaeration, and pulping—of which the last four are conducted under vacuum conditions. Heating is achieved through a screw conveyor blancher equipped with direct steam injection, while the vacuum operations are synchronized using double-valve airlocks. Performance was assessed using açai and Andean blackberry, evaluating microbial inactivation, physicochemical and rheological properties, and energy efficiency. FVE-treated purees showed complete microbial inactivation (<10 CFU/g), significant increases in pulp yield and extraction efficiency, reduced insoluble solids, enhanced pigment release, and superior rheological consistency. Energy consumption analysis revealed specific energy consumption (SEC) values as low as 0.97 MJ/kg—markedly lower than conventional processing benchmarks. The proposed FVE system represents a scalable and energy-efficient solution for producing high-quality fruit purees
Who suffers the heat? Partial adaptation and persistent inequalities in France
No full textInternational audienceThis paper examines the heterogeneous effects of extreme heat on mortality in France, highlighting disparities across population density, socio-economic characteristics, and time. Using a new monthly database of French municipalities from 1980 to 2019, I exploit year-to-year random variations in temperature to show that extreme heat significantly increases the mortality rate, especially for people aged 75 and over. The study also emphasizes the greater vulnerability of people living in densely populated cities due to structural challenges that amplify the impact of high temperatures. Socio-economic conditions also shape vulnerability, as low-income municipalities face a disproportionate impact, especially in rural areas. Indeed, the paper’s key contribution is to disentangle the effects of urban density and income on the heat–mortality relationship, showing that social inequalities in the effects of high temperatures are particularly pronounced in rural settings. The results also show a major reduction in the impact of heat following the extreme 2003 heatwave, partly due to the National Heatwave Plan implemented in response to this event
Comparison of different strategies based on β-casein dynamics to encapsulate curcumin in casein micelles
No full textInternational audienceCasein micelles (CM) are colloidal phospho-protein-mineral complexes naturally present in milk. Cooling inducesβ-casein dissociation from CM. The aim of the present research is to improve curcumin encapsulation in β-casein depleted CM. This study proposes an extraction and separation process including cooling, low acidification (pH 5.8) and membrane filtration at a pilot scale allowing a removal of 45 ±5 % of β-casein fraction from CM.Special care was taken to preserve the CM integrity. Investigation of the depleted CM topography by atomic force microscopy (AFM) reveals a swelling of the micellar structure with a mean width of 193 ±10 nm and a mean height of 80 ±5 nm. Concurrently, exploration of the elastic properties displays a stiffer nanomechanicalsignature compared to native CM, with a mean elasticity modulus of 195 ±17 kPa. The β-caseins extracted from CM were bound to curcumin prior to their encapsulation in depleted CM. This new encapsulation strategy was compared to two other methods, and the results show that it significantly increases the binding efficiency of curcumin to CM
Macro-scale damage characterization of Wharton’s jelly membrane undergoing tension
No full textInternational audienceThe Wharton’s jelly, a mucoid connective tissue of the umbilical cord, is promising for regenerative medicine applications. However it is relatively new and poorly documented especially from a mechanical point of view. To help filling the gap in the literature lack of data, this study seeks to address the Wharton’s jelly damage behavior by providing first key results through an efficient analytical approach. The tensile and damage behavior of Wharton’s jelly membranes is studied using tensile tests conducted up to failure under close physiological conditions. The Wharton’s jelly mechanical response has been characterized using an hyperelastic constitutive model based on the Ogden formulation, enhanced with continuum damage mechanics to capture analytically the damage behavior. To support the mechanical analysis, optical coherence tomography was used to assess the stress-free microstructural arrangement of the collagen fibers, revealing a transversely isotropic architecture. This qualitative insight into the internal structure enriched the interpretation of the mechanical behavior. Overall, this analytical study enabled the identification of a comprehensive set of material parameters characterizing both elastic and damage responses. Pearson correlation matrices were used to reveal meaningful relationships between parameters, potential predictive descriptors, and model’s limitations. These findings provide a solid foundation for future modeling developments through numerical simulation and offer new outlooks for surgery and dressing applications
