HAL Collection UNC (Univ. de la Nouvelle Calédonie)
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Clause de conciliation, responsabilité de l'avocat et perte de chance
No full textInternational audienc
Temporalité et contenu des notifications d’alerte cyclonique diffusées à la population à La Réunion et Mayotte (2023-2025) : des exemples à suivre ?
No full textInternational audienceNumerous alerts (n=10) were broadcasted with the FR-Alert solution during the passage of several cyclonic hazards (n=5) near the islands of La Réunion and Mayotte, from December 2023 to February 2025. But when were these alerts triggered, and with which content ? To answer these questions, this article aims at : 1) analyzing the temporality of the warnings in relation to the vigilance levels set by Météo France, and 2) scoring the content of messages which often explained the nature of the phenomenon in progress and reminded people of the safety instructions expected. Several notifications were sent out 3 hours before the red alert level, allowing time for confinement, and such a practice (introduced in the ORSEC Cyclones plan) can be put into perspective in relation to the kinetics of other dangerous hazards, which could also be the subject of mass alerts.Cet article analyse la temporalité et le contenu de 10 notifications d’alerte cyclonique qui ont été diffusées à la population lors du passage de 5 cyclones (Freddy, Belal, Chido, Garance et Dikeledi), sur les îles de La Réunion et Mayotte, entre décembre 2023 et février 2025. En mobilisant différentes sources de données (les horaires des vigilances de Météo France, les documents de planification opérationnelle en vigueur, le site internet du dispositif FR-Alert, et les résultats d’enquêtes menées auprès des autorités et de la population), cet article met en évidence des points de similitude, mais également certaines particularités territoriales et des évolutions au-fur-et-à-mesure de la pratique. Ces résultats invitent à débattre de la manière d’optimiser les alertes, dans ces territoires mais aussi sur l’ensemble du territoire national
Chemical and Biological Investigation of the PNG Xanthostem species of the MYRTACEAE family
No full textInternational audienceThe isolation, identification of chemical constituents and bioactivity of the volatile oil of three species of Xanthostemon (Myrtaceae) in PNG will be presented. This research is part of the Pacific Islands Universities Research Network (PIURN). In this study, leaves of three Xanthostemon out of four species occurring in PNG were chemically and biologically investigated. These included X. petiolatus, X. crenulatus, and Xanthostemon sp. (formally known as X. kasikasi ). The phytochemicals identified were mainly β-triketones & terpenes. From the volatile oil of X. petiolatus, three β-triketones including flavesone, isoleptospermone and leptospermone were identified and three terpenes including cyclocolorenone, viridiflorol and palustrol were identified. X. crenulatus volatile oil contained two β-triketones including flavesone and isoleptospermone and majority of the constituents were terpenes including caryophyllene oxide, spathulenol, β-bisabolene, humulene epoxide, ar-curcumene, caryophylla-3,8(13)-dien-5-alpha-ol, nerolidiol E, β-farnesene E, caryophylla-4(12),8(13)-dien-5alpha-ol, β-bisabolol, ar-curcumen-15-al, patchoulene and farnesol (2Z,6Z). From Xanthostemon sp., four β-triketones were found including leptospermone, isoleptospermone, flavesone & papuanone and five terpenes namely β-selinene, trans-nerolidol, selina-6-en-4-ol, alpha-selinene and viridiflorol were detected. The hydro-distillation technique was employed to isolate the volatile oils and the technique of gas chromatography was used to determine the constituent biomolecules. The anti-microbiological property of the oils was assessed via disc diffusion or agar overlay technique against some pathogenic bacteria and fungi. The results indicated promising anti-microbial activities from all three species against four bacteria (2 G+ and 2 G-), a protozoa and four fungi. The nematicidal and termiticidal activity of the oil was assessed against the eggs of Meloidogyne incognita and Coptotermes formosanus (termites) respectively which also showed positive results. The diabetic property of the oils was also assessed with no positive results. Laboratory assays were carried out to test the hatchability of the eggs of M. incognita, susceptibility of Coptotermes formosanus and inhibition activity of alpha-amylase and alpha-glucosidase
Advanced Love wave sensor based on algal polymers for the detection of mercury in French Guiana waters
No full textInternational audienc
Transition agroécologique en Polynésie française : gouvernance et résilience face aux défis climatiques et alimentaires
No full textInternational audienceThis article offers an in-depth analysis of the agroecological transition in French Polynesia, comparing the resilience potential of local agricultural practices with the major structural challenges that hinder its institutionalisation. The study is based on a mixed (qualitative and quantitative) approach conducted in nine representative study areas across the archipelagos, which makes it possible to characterise the diversity of production systems, from micro-subsistence farming to high value-added niche sectors. The results demonstrate significant agricultural vitality, particularly through the ubiquity of self-consumption (estimated at 18 billion Fcfp) and exceptional adaptation to island constraints through techniques such as agroforestry (fa'a'apu) and island composting. However, the article reveals that the widespread adoption of this transition is compromised by land ownership issues linked to joint ownership, which paralyses productive investment and compromises generational renewal in the sector. The discussion therefore proposes concrete governance levers – notably the creation of a public agricultural land agency and the establishment of innovative guarantee mechanisms – to unlock financing and ensure the sustainability and food sovereignty of French Polynesia.Cet article propose une analyse approfondie de la transition agroécologique en Polynésie française, en confrontant le potentiel de résilience des pratiques agricoles locales aux défis structurels majeurs qui entravent son institutionnalisation. L'étude repose sur une approche mixte (qualitative et quantitative) menée sur neuf terrains d'étude représentatifs des archipels, ce qui permet de caractériser la diversité des systèmes de production, de la micro-exploitation vivrière à la filière de niche à forte valeur ajoutée. Les résultats démontrent une vitalité agricole significative, notamment à travers l'omniprésence de l'autoconsommation (estimée à 18 milliards Fcfp) et l'adaptation exceptionnelle aux contraintes insulaires par des techniques comme l'agroforesterie (fa'a'apu) et le compostage insulaire. Cependant, l'article révèle que la généralisation de cette transition est compromise par le blocage foncier lié à l'indivision, qui paralyse l'investissement productif et compromet le renouvellement générationnel du secteur. La discussion propose, dès lors, des leviers de gouvernance concrets -notamment la création d'une foncière agricole publique et l'établissement de mécanismes de garanties innovantes -pour débloquer le financement et assurer la pérennité et la souveraineté alimentaire de la Polynésie française.</div
A New Reconstruction Method for Generating a Realistic Tropical Cyclone Wind Field
No full textTropical Cyclones (TCs), with their destructive power, represent a major threat to coastal regions. Existing global reanalyses, that provide long-term atmospheric data, suffer from an underestimation of TC winds due to their relatively coarse resolution. Simplified surface wind parametric models fitted on observations are thus extensively used for risk assessments related to the TC-induced wind and ocean response (e.g. for driving surge or wave models), but their ability to capture the complexity of TC wind fields remains limited. Taking advantage of newly available high-resolution observations of the 2D surface wind field in TCs provided by Synthetic Aperture Radar (SAR) data, state-of-the-art existing reanalysis of synoptic winds, and an advanced parametric formulation able to represent a variety of TC shapes, the present study proposes a methodology to build global atmospheric wind fields including more realistic TCs. Based on SAR observations, we first provide an optimized parameterization of the TC wind profile as a function of best-track variables (maximum wind speed, radius of maximum wind and latitude of the TC center). The TC wind field is then blended with a global reanalysis "background" wind field, allowing to provide a full asymmetric wind field associated to the local synoptic conditions. The newly created TC wind fields are evaluated against observations showing consistent intensity, asymmetry, and storm size, strongly improving the structural and energetic characteristics of the represented TCs compared to the original reanalysis surface wind. This work provides key insights into the representation of TC wind fields in long-term reanalyses for studies requiring realistic estimates of the spatio-temporal distributions of TC surface winds
Partager le pouvoir en “société profondément divisée” : regards croisés depuis la Nouvelle-Calédonie
No full textInternational audienc
How could climate change affect the magnitude, duration and frequency of hydrological droughts and floods in West Africa during the 21st century? A storyline approach
No full textInternational audienc
Dynamiser l'enseignement des appareillages en spectroscopie : l'intégration d'un jeu sérieux - Spectrowave
No full textInternational audienceTo enhance learning and strengthen student interest, involvement, and motivation, a serious game was introduced at the L3 and M1 levels. This game enables students to develop knowledge of the components and functioning of the spectroscopy instruments most commonly used in analytical laboratories. In this article, we describe the evolution of the game, from its initial physical board format to its digital version, which can be played online and remotely. We also discuss improvements implemented over time, particularly the addition of interactions during sessions, which have proven essential for maintaining student engagement.Afin de faciliter l’apprentissage et accroître l’intérêt, l’implication et la motivation des étudiants, un jeu sérieux basé sur un jeu de plateau a été introduit en L3 et M1. Cet « edugame » permet aux étudiants d’acquérir des connaissances sur les composants et le fonctionnement des appareils de spectroscopie les plus couramment utilisés en laboratoire d’analyse. Dans cet article, nous présentons l’évolution de ce jeu, de sa version sur un plateau physique à une version numérique jouable en ligne et en distanciel. Enfin, nous discuterons des améliorations apportées, notamment l’ajout d’interactions en séance, qui se sont révélées essentielles pour maintenir l’engagement des étudiants