Portail "HAL-Francophonie Afrique et Océan Indien"
Not a member yet
43052 research outputs found
Sort by
Floribundamide a new phytosphingosine type ceramide and other constituents with antileishmanial, cytotoxic, antibacterial and enzyme inhibitory activities from the leaves of Holarrhena floribunda
No full textInternational audienceHolarrhena floribunda (Apocynaceae) is used ethnomedicinally in Cameroon for the treatment of various ailments. This study aimed to isolate and identify natural products with potential antileishmanial, cytotoxic and antimicrobial natural products from the leaves of Holarrhena floribunda. The methanol extract yielded one previously undescribed phytosphingosine-type ceramide, floribundamide (1), together with nine known compouds (2–10). Structural elucidation was achieved through extensive NMR and mass spectroscopic analyses and comparison with literature data. Moreover, due to the growing concern over drug-resistant pathogens, the isolated compounds were evaluated for their antiparasitic and antibacterial properties. The isolated compounds were assessed in vitro for their antileishmanial activities against Leishmania donovani 1S (MHOM/SD/62/1S) promastigotes along with their cytotoxicity properties on Raw 264.7 macrophage cells respectively: the plant exhibited potent leishmanicidal activity (IC50 = 3.98 ± 0.86 µg/mL) with low selectivity index (SI = 2.66), whereas 2 and 3 showed moderate leishmanicidal activities with IC50 = 15.17 and 19.23 μg/mL (33.2 and 45.1 µM) respectively. Antibacterial activity was assessed against five bacterial strains using the broth microdilution method: the crude extract showed good inhibitory effects against Gram-positive (Baccilus subtilis ATCC 6633 and Staphylococcus aureus ATCC 6538) and Gram-negative bacteria (Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 1705 and Pseudomonas aeruginosa ATCC 15442). The compounds exhibited antibacterial activity against most of the tested bacteria with minimum inhibitory concentration (MIC) values ranging from 0.03125 to > 0.25 mg/mL, respectively. Compound 9 showed the highest antibacterial activity against all bacterial strains (MICs; 0.03125–0.25 mg/mL). Finally, the methanol extract displayed mild protein kinase inhibition activity. To the best of our knowledge, this is the first report of the antileismanial, cytotoxic and protein-kinase inhibitory properties on this H. floribunda
Olfaction in fruit flies (Tephritidae) balances detection and discrimination of host fruits
No full textAbstract Phytophagous insects locate suitable hosts through volatile compounds. Polyphagous species face a particular challenge because their hosts emit diverse chemical profiles, yet their olfactory strategies remain unclear. A long-standing assumption suggests that these insects respond primarily to compounds shared across hosts. Here we show that olfactory responses of various polyphagous fruit fly species (Tephritidae) are instead tuned to species-specific fruit compounds from 28 host fruits. This tuning translates into a behavioural preference for species-specific over shared fruit compounds, but only at low doses. Previously, response probability in the same species had been reported to be tuned to shared fruit compounds. To reconcile these observations, we propose a working hypothesis, supported by a computational model: an inverse relationship between olfactory response amplitude and probability may have evolved under the ecological need to detect and discriminate hosts. Together, these results highlight how polyphagous Tephritidae balance detection and discrimination through finely tuned olfactory mechanisms. This insight not only advances our understanding of host selection in polyphagous insects but also has potential applications for ecological management and pest control strategies
La Guerre des sables de 1963
No full textInternational audienceThis article revisits the 1963 “War of the Sands” and examines Cuba’s decisive role in providing military support to newly independent Algeria. Drawing on diplomatic archives, press sources and political testimonies, it argues that the Cuban intervention – the island’s first internationalist military mission – functioned both as an act of revolutionary solidarity and as a means of projecting influence within the Third World. The episode is shown to be central to the consolidation of Algerian-Cuban relations and to the emergence of an autonomous South–South diplomacy during the Cold War.Este artículo vuelve sobre la “Guerra de las Arenas” de 1963 y analiza el papel decisivo desempeñado por Cuba en el apoyo militar a la Argelia recién independizada. A partir de archivos diplomáticos, fuentes de prensa y testimonios de actores políticos, muestra que la intervención cubana – primera misión internacionalista de la isla – fue a la vez un gesto de solidaridad revolucionaria, un medio de afirmación en la escena del Tercer Mundo y un elemento clave en la consolidación de las relaciones argelino-cubanas. El estudio esclarece así la manera en que este episodio contribuyó a estructurar una diplomacia Sur-Sur autónoma en el marco de la Guerra Fría.Cet article revient sur la « Guerre des sables » de 1963 et analyse le rôle décisif joué par Cuba dans le soutien militaire à l’Algérie nouvellement indépendante. À partir d’archives diplomatiques, de sources de presse et de témoignages d’acteurs politiques, il montre que l’intervention cubaine – première mission internationaliste de l’île – a été à la fois un geste de solidarité révolutionnaire, un moyen d’affirmation sur la scène du Tiers-Monde et un élément clé dans la consolidation des relations algéro-cubaines. L’étude éclaire ainsi la manière dont cet épisode a contribué à structurer une diplomatie Sud-Sud autonome au sein de la guerre froide
Ethnobotanical Study of Medicinal Plants Used in the Treatment of Diseases in the Kangu Grouping
No full textInternational audienceAims: This study aimed to establish a systematic ethnobotanical inventory of medicinal plants used by vendors and traditional healers for the treatment of human diseases in the Kangu community, Democratic Republic of Congo. Specifically, it sought to identify the main afflictions treated, the most frequently used plant parts, and the predominant modes of preparation and administration.Study Design: A descriptive ethnobotanical survey based on structured questionnaires and statistical analysis.Place and Duration of Study: Conducted in the Kangu Grouping between January and June 2025.Methodology: Data were collected from 30 respondents, including traditional healers and herbal vendors, through structured questionnaires and interviews. Plant species were identified and therapeutic indications categorized. Descriptive statistics were applied to analyze citation frequencies, plant parts used, and preparation modes. A total of 67 medicinal species were documented.Results: The respondents reported 67 species used to treat 40 afflictions grouped into 10 categories. Malaria emerged as the most frequently cited condition, followed by gastrointestinal disorders and reproductive health issues. Leaves were the most commonly used plant part, while enemas and oral intake represented the predominant modes of administration.Conclusion: This study provides a baseline ethnobotanical inventory of medicinal plants in the Kangu community, emphasizing their cultural and therapeutic relevance. The findings highlight species of potential pharmacological interest and underscore the importance of preserving traditional knowledge. They also open new avenues for validation and safe integration of local remedies into future clinical research, while promoting sustainable use of biodiversity
chapitre 3 : Mesurer l’employabilité des seniors : enjeux, évolutions et outils comparés
No full textInternational audienc
Draft genome sequence data on Streptomyces salinarius MPA0124 isolated from coastal sediments of Pondicherry, India
No full textInternational audienceStreptomyces salinarius MPA0124, a halotolerant actinobac- terium, was isolated from coastal sediments of Pondicherry, India, using Bennett’s agar supplemented with 5 % NaCl. The draft genome, sequenced using the Illumina HiSeq plat- form, comprises 8.01 Mb across 122 contigs with a GC con- tent of 72.22 %. Genome annotation predicted 7548 coding sequences, 70 tRNAs, and 4 rRNAs, indicating a metaboli- cally diverse genetic repertoire. Functional analysis revealed a broad array of carbohydrate-active enzymes (CAZymes) in- volved in cellulose, hemicellulose, pectin, and lignin degrada- tion, highlighting the strain’s role in polysaccharide turnover and carbon recycling in saline ecosystems. Phylogenomic analysis clustered S. salinarius MPA0124 closely with S. salinarius SS06011 and S. ardesiacus NBRC15402, confirm- ing its taxonomic placement within the Streptomyces genus. The genomic dataset enriches the current knowledge of marine-derived Streptomyces and underscores its potential for biotechnological applications in biomass conversion, enzyme discovery, and biosaline agriculture. The genome sequence has been deposited in NCBI under the accession number NZ_JBJDRC0 0 0 0 0 0 0 0 0.1
Implementation of a multiresolution analysis method to characterize multi-scale wave structures in lidar data
No full textInternational audienceExtracting gravity wave (GW) perturbations from atmospheric observations relies on background removal tech- niques whose results may differ depending on the obser- vational type and the spectral characteristics of the chosen method. This variability complicates the intercomparison of GW properties across instruments, sites, and studies. Night- time averaging provides a simple estimate of the background but may smooth out smaller-scale structures. Spectral filter- ing enables targeted wavelength extraction, though it can be sensitive to noise and edge effects. Sliding polynomial fit of- fers flexibility but may suppress relevant signals depending on the polynomial degree. To address this issue, we imple- ment and evaluate a processing method based on multireso- lution analysis (MRA), designed to better extract and charac- terize the background and the multi-scale structures of GWs in lidar temperature and wind profiles. The MRA approach is then evaluated in comparison to these techniques and applied to lidar temperature and wind measurements collected on the night of 20 November 2023 at La Réunion. By decomposing the signal into dyadic vertical wavelength bands and an ap- propriate choice of corresponding details, the MRA can im- prove the detection of GW-induced perturbations in the spec- tral range of 0.8 to 12.8 km vertical wavelength by simulta- neous background removal and denoising. We use the vari- ance method as a benchmark for determining gravity waves potential energy (GWPE) and ask the question: “How well do the different filtering techniques compare with the vari- ance method?” Given an overall agreement between our de- velopped MRA and the variance method, we conclude thatthe MRA can also be used to determine reliable gravity wave kinetic energy (GWKE).Beyond energy estimation, MRA provides a unique capa- bility to compute kinetic and potential energy profiles for tunable vertical wavelength bands, enabling the characteri- zation of vertical and temporal evolution and interactions be- tween different GW scales. These results establish MRA as a robust and complementary tool for improving GW analy- ses from lidar measurements, with promising applications to long-term climatologies and multi-instrument observational strategies
From the abyss to efficiency: Optimizing Sea Water Air Conditioning (SWAC) for sustainable cooling
No full textInternational audienceAs global cooling demand grows, improving air conditioning efficiency while reducing its environmental impact is an urgent challenge. Sea Water Air Conditioning (SWAC) harnesses deep seawater as a renewable cooling source and offers a promising low-carbon alternative to conventional systems. This study presents a parametric sensitivity analysis and a multi-objective optimization of a large-scale SWAC installation in French Polynesia, using a numerical model validated by experimental data and coupled with a dynamic building simulation. Key design and operational parameters, such as seawater intake temperature, chilled water loop configuration, and heat exchanger effectiveness, are identified using the Morris method and optimized through a Non-dominated Sorting Genetic Algorithm. Results show that the global coefficient of performance can be increased from 24.7 up to 85.6, nearly 24 times higher than typical values for split-system air conditioners, while preserving comfort and adequate dehumidification. Raising the seawater intake temperature from 5 • C to 8 • C significantly reduces capital costs, resulting in major economic benefits: the Levelized Cost of Cooling decreases from 0.312 /kWh, the payback period shortens from 15 to 7 years, and the Net Present Value nearly doubles. These results highlight SWAC's potential as a high-efficiency, economically viable, and climate-resilient cooling solution. Furthermore, coupling SWAC with complementary systems such as OTEC could enhance resource utilization, reinforce its contribution to net-zero targets, and broaden its applicability in tropical and coastal regions
Modélisation des hauteurs d’eau dans les plaines d’inondation avec les GNN
No full textInternational audienc
Ten years of GNSS field campaigns covering a full eruptive cycle at Piton de la Fournaise (2014–2023)
No full textInternational audienceThe most recent eruptive cycle of Piton de la Fournaise (La Réunion Island) lasted from June 2014 to August 2023, during which 25 eruptions and 9 intrusions occurred, producing significant ground deformation. To more accurately quantify ground displacements, the Observatoire volcanologique du Piton de la Fournaise (OVPF) of the Institut de physique du globe de Paris (IPGP) operates a network of ground markers whose positions are measured periodically during dedicated Global Navigation Satellite System (GNSS) field campaigns. This network, in its current configuration, was installed in the early 2000s on the terminal cone—the most active and deformed part of the volcano—complementing the observatory’s permanent ground deformation network. This report presents data from 27 measurement campaigns conducted during the 2014–2023 eruptive cycle of the Piton de la Fournaise volcano. During this cycle, the terminal cone exhibited asymmetric east-west displacements, highlighting the preferential motion of the eastern flank. Maximum horizontal and vertical displacements of 2.56 ± 0.02 m eastward (at mid-slope, east of the terminal cone) and 1.94 ± 0.05 m upward (at the summit), respectively, were recorded. The data presented and provided in this paper open new research perspectives for long-term analyses of ground deformation at Piton de La Fournaise, including investigations into the instability of the eastern flan