HAL Collection UNC (Univ. de la Nouvelle Calédonie)
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Contrasting Patterns of Connectivity Between Populations of Euphotic and Mesophotic Hydroids in Reunion Island Support the Deep Reef Refuge Hypothesis
No full textInternational audienceIn the context of coral reef decline, mesophotic coral ecosystems (MCEs, 30–150 m) offer hope for the recovery of degraded euphotic reefs. The Deep Reef Refuge Hypothesis (DRRH) postulates the potential of mesophotic reefs to reseed euphotic reefs. This hypothesis needs to be further tested by estimating connectivity along the depth gradient. Mesophotic data are lacking worldwide, particularly in the southwestern Indian Ocean (SWIO). Here, using a total of 2218 samples collected at depths ranging from 10 to 103 m, we estimated the connectivity of 7 hydroid species sampled at euphotic, upper, and lower mesophotic depths around Reunion Island using a multi‐species comparative framework. Population genetic analyses using 8–17 microsatellite markers per species (80 markers in total) as well as Bayesian inference were performed to estimate population structure and contemporary migration rates to highlight connectivity patterns and directionality of gene flow between depths. The results revealed three main genetic patterns depending on the species: a horizontal stepping stone pattern between areas around the island, a vertical stepping stone pattern between adjacent depths, and a quasi‐panmictic pattern. Each species showed some specificity within these patterns, but overall, at least 4 of the 7 species support the assumption of vertical connectivity from the Deep Reef Refuge Hypothesis, highlighting the importance of studying multiple species. The existence of vertical connectivity between euphotic and mesophotic depths in the southwestern Indian Ocean confirms the importance of mesophotic coral ecosystems for conservation efforts and our global understanding of coral reef ecosystem dynamics
Marine animal forest formed by gorgonians Subergorgia on near‐shore mesophotic ecosystems in Reunion Island
No full textInternational audienceMesophotic coral ecosystems (MCEs), occurring between 30 and 150 m depth, are increasingly recognized for their ecological importance, yet they remain underexplored, particularly in the southwestern Indian Ocean. During benthic surveys conducted at depths ranging from 15 to 75 m off northwestern Reunion Island, we documented a dense and extensive marine animal forest (MAF) dominated by large arborescent octocorals Subergorgia cf. suberosa . This monospecific community formed a complex three‐dimensional habitat spanning a substantial area at mesophotic depths over the northwestern abrupt slopes of Reunion Island. Colonies reached over 1.5 m in height, providing structural habitat for diverse fish and macroinvertebrate assemblages. A total of 53 fish species from 22 families were recorded in association with this MAF, alongside numerous epibionts and understory anthozoans. Despite its ecological value, this habitat faces significant anthropogenic pressures, particularly from fishing activities. Nearly 25% of photographed S . cf. suberosa colonies were entangled in fishing lines, with visible damage including tissue necrosis and polyp loss affecting up to 47% of colonies. These impacts, along with sedimentation from runoff, raise concerns for the long‐term persistence of this mesophotic habitat‐forming community, as long‐lived, slow‐growing organisms like gorgonians may be more impacted by these types of disturbances and take longer to recover than fast‐growing organisms. Our findings represent the first quantitative assessment of Subergorgia dominance and associated biodiversity in this region and highlight its role as a potential refuge for shallow reef taxa. The ecological significance, spatial extent, and fragility of this MAF underscore the urgent need for spatially replicated surveys, targeted conservation strategies, and regulation of damaging activities such as fishing. We advocate for increased research efforts focused on mesophotic habitats, with particular attention to the population dynamics and ecological functions of large gorgonians, to better understand the role of MCEs in reef resilience under accelerating environmental changes
Exploring the Digital Health Landscape: How adolescents living in urban and rural Vanuatu use online platforms to access health information (anonymized version of the dataset and supplementary tables)
No full textDeposit containing the anonymized version of the dataset and supplementary tables related to the scientific paper: Amon KL, Wattelez G, Nedjar-Guerre A et al. Exploring the Digital Health Landscape: How adolescents living in urban and rural Vanuatu use online platforms to access health information [version 3; peer review: 1 approved, 3 approved with reservations]. Open Res Europe 2025, 5:148 (https://doi.org/10.12688/openreseurope.19670.3)This anonymized deposit contains two files related to Amon et al. 2025: _ 2024-12-09_FALAH_Vanuatu_socialMediaUse_Zenodo_anonymized.csv: csv file with anonymized information about the participants including their answers. _ FALAH_Vanuatu_Digital Landscape_Supplementary tables.pdf: pdf file with 3 supplementary tables. Data anonymized from self-report questionnaires on owning a mobile phone, actions performed with a computer and/or a tablet and with a mobile phone and the use of digital media for health. Participant characteristics: 13 to 20 years old students. Number of participants: 197. Year of the study: 2023. Place of the study: Vanuatu. The restricted non-anonymized dataset can also be found on Wattelez, G., Amon, K., Nedjar-Guerre, A., Forsyth, R., Peralta, L., Urvoy, M.-J., Caillaud, C., & Galy, O. (2024). Exploring the Digital Health Landscape: How adolescents living in urban and rural Vanuatu use online platforms to access health information (non-anonymized version) (1.0.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.1432339
Exploring the Digital Health Landscape: How adolescents living in urban and rural Vanuatu use online platforms to access health information
No full textInternational audienceBackground Investigating the use of online platforms by adolescents living in the Pacific Islands is important to understand how they navigate online resources to make informed decisions about their health. This study explores the use of online platforms, by adolescents in Vanuatu for health-related purposes. Methods A total of 197 students (58% from an urban school and 42% from a rural school) completed a survey which collected quantitative and qualitative data about their use of digital technologies for health. Results Results show that 77% of participants owned a mobile phone, which was mostly used to listen to music (34%) and play games (22%). Only 24% (n= 47) reported to have used apps, social media or websites for their health. Social media was the preferred category to use for health information, among both urban (25%) and rural (11%) participants, with Facebook, TikTok, YouTube, Instagram, and Twitter being the most frequently mentioned platforms. Reasons included, to gain knowledge, watch videos, chat with friends and look at posts. To search for health information, social media was more commonly used by rural students (12%) compared to urban students (8%). Conversely, search engines were more popular among urban students (12%) than rural students (5%). For discussing health topics online, social media was the predominant platform in both urban (10%) and rural (9%) areas. Conclusions While reports often suggest a digital divide between urban and rural areas, results from our study challenge this with our findings showing similarities in the use of online platforms for health information between urban and rural adolescents in Vanuatu. Our paper considers the influencing factors of social media use for health-related purposes, reflects on cultural sensitivity, identifies the risks of misinformation and regards the role of policy and education as essential for effectively engaging this population with digital health tools, to promote positive health outcomes
Évaluer les comportements des adolescents en matière d’activité physique à l’aide des données d’accéléromètre
No full textInternational audienceLes enfants et les adolescents vivant dans le Pacifique sont très touchés par le problème de surpoids et d’obésité. En effet, la prévalence de l’obésité infantile peut atteindre plus de 20% dans la plupart des pays polynésiens et mélanésiens [NCD-RisC 2017], voire plus de 30% chez les adolescents [Frayon et al. 2020]. Bien que ce problème de santé publique soit multifactoriel, il est reconnu qu’un mode de vie trop sédentaire soit un facteur favorisant l’obésité ayant pour conséquence une augmentation du risque de développer des maladies non transmissibles telles qu’un diabète de type 2 ou des maladies cardiovasculaires [WHO 2016].Pour mieux comprendre le comportement des adolescents en matière d’activité physique (AP), des mesures objectives sont enregistrées à l’aide d’accéléromètres afin d’obtenir des estimations précises de leurs mouvements et des niveaux d’AP associés [Phillips et al. 2013, Wattelez et al. 2025]. Les participants portent l’accéléromètre au poignet comme une montre durant 7 jours consécutifs. Les enregistrements des accélérations se font dans les trois dimensions à une fréquence de 60 Hz, fournissant des fichiers d’environ 700 à 800 Mo pour chaque participant.Dans la pratique, pour le traitement, les données provenant des trois dimensions sont généralement agrégées en un seul signal avec un pas d’une seconde. Ce signal est appelé magnitude du vecteur de support (Support Vector Magnitude – SVMg) [Diaz et al. 2020]. A partir des valeurs de ce signal, il est possible de déterminer pour chaque seconde un niveau d’AP classifié comme suit :Sédentaire : SVMg<4,5Légère : 4,5 ≤SVMg<16,5Modérée : 16,5 ≤SVMg<42Vigoureuse : SVMg>42Dans la plupart des cas, les études de santé publique s’intéressent à l’AP modérée et vigoureuse (APMV) par agrégation des deux derniers niveaux. Par une suite de traitements, les temps journaliers dans lesquels les participants s’engagent dans chaque niveau d’AP sont obtenus et utilisés pour classifier les journées et regrouper des comportements similaires. Cela a permis de détecter des modifications de comportement de certains participants relativement à la pratique de l’AP [Diaz et al. 2020].Cependant, la forte agrégation des données d’entrée par la méthode présentée entraîne une grande perte d’information. C’est pourquoi, des études récentes ont proposé des méthodes d’analyse de série temporelle telles que des modèles ARIMA et des méthodes impliquant des modèles de deep learning pour utiliser ces informations dans leur globalité couplées à d’autres informations comportementales telles que les habitudes alimentaires [Wang et al. 2022, Yu et al. 2025]. Ces études qui avaient pour but de proposer des modèles prédictifs du statut pondéral ont obtenu des résultats encourageants avec environ 83% de précision. Actuellement, des projets sont en cours pour utiliser d’autres techniques telles que la détection de motifs ou l’ACP fonctionnelle afin d’analyser ces données en tant que séries temporelles.RéférencesDíaz C., Galy O., Caillaud C., Yacef K., “A Clustering Approach for Modeling and Analyzing Changes in Physical Activity Behaviors From Accelerometers”, IEEE Access, vol. 8, pp. 224123-224134, 2020, doi: 10.1109/ACCESS.2020.3044295.Frayon S., Wattelez G., Paufique É., Nedjar-Guerre A., Serra-Mallol C., Galy P. “Overweight in the pluri-ethnic adolescent population of New Caledonia: Dietary patterns, sleep duration and screen time”, The Lancet Regional Health – Western Pacific 2, 2020, 100025; https://doi.org/10.1016/j.lanwpc.2020.100025NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128·9 million children, adolescents, and adults. Lancet Lond Engl. 2017 Dec 16;390(10113):2627–42.Phillips L.R.S, Parfitt G., Rowlands A.V. “Calibration of the GENEa accelerometer for assessment of physical activity intensity in children”, Journal of Sciene Medical Sport, 2013, 16, pp. 124-128, https://doi.org/10.1016/j.jsams.2012.05.013.Wang Y., Wattelez G., Frayon S., Caillaud C., Galy O., Yacef K. “ABIPA: ARIMA-based integration of accelerometer-based physical activity for adolescent weight status prediction”, Transactions on computing healthcare, 2022, https://doi.org/10.1145/3561611.Wattelez G., Frayon S., Galy O. “Assessing physical activity/behavior of adolescents living in the Pacific with accelerometer data: 231 GENEActiv records in New Caledonia”, Data in Brief, 2025, 111228. https://doi.org/10.1016/j.dib.2024.111228.World Health Organization, Commission on Ending Childhood Obesity, World Health Organization. Report of the Commission on Ending Childhood Obesity. [Internet]. 2016 [cited 2020 May 4]. Available from: http://apps.who.int/iris/bitstream/10665/204176/1/9789241510066_eng.pdfYu X., Kim J.Y., Wattelez G., Galy O., Caillaud C., Yacef K. “TimePAD: Leveraging Time-Based Physical Activity Features and Digital Dietary Intake for predicting Healthy Weight Status: a case study with Pacific islands adolescents”, JMIR mHealth and uHealth, 2025, https://doi.org/10.2196/preprints.7024
Les principes fondamentaux reconnus par les lois de la République et le droit local de l'enseignement
No full textInternational audienceNote sous Cons. const., 2 juillet 2025, no 2025-1145 QPC, École Mathias Grünewald et autr
L’impact du télétravail sur le management des équipes dans les cabinets d’audit
No full textInternational audienceSince the health crisis, audit firms have had to adapt in order to meet employees' demands, particularly in terms of remote work. Firm managers are at the core of this change : the middle tier between young, junior auditors (whom they supervise) and firm partners (to whom they report). Thanks to a qualitative study, we prove, by using situational leadership theory and social learning theory, that remote work modifies both the manager's "technical" role and their "support" dimension.Depuis la crise sanitaire, les cabinets d’audit ont dû s’adapter pour répondre aux exigences des employés, en particulier en termes de télétravail. Au centre de ce changement se trouvent les managers de cabinet : échelon intermédiaire entre les jeunes auditeurs débutants (qu’ils encadrent) et les associés de cabinets (à qui ils rendent comptent). À travers une étude qualitative, nous montrons, en mobilisant la théorie du leadership situationnel, que le télétravail modifie à la fois le rôle « technique » du manager et sa dimension « de soutien »
Mon Bagne
No full textInternational audienceAlphonse Humbert (1844-1922) fut un ardent républicain. Signataire de la célèbre « Affiche rouge » qui proclame « Place à la Commune ! » dès janvier 1871, il s'engage par la plume, au Père Duchêne. Après la Semaine sanglante, Humbert est arrêté, traduit en conseil de guerre et condamné aux travaux forcés à perpétuité.Voici son récit. Trop longtemps oublié, il n'était paru qu'en feuilleton dans la presse radicale entre 1880 et 1881. Humbert y décrit de sa plume alerte et précise ses premières années de bagne (1872-1875) : d'abord Toulon, puis le convoi de la Virginie, à destination de la Nouvelle-Calédonie. Là-bas, aux antipodes, une toute-puissante administration pénitentiaire préside aux destins des « scélérats » dont la France souhaite se débarrasser, tout en s'abritant derrière un projet de colonisation basé sur leur réhabilitation.La jeune colonie pénale et ses installations sont abondamment décrites dans ce texte, qui constitue une source de premier plan pour l'histoire de cet archipel. Plus et mieux que les autres forçats qui nous ont laissé leurs mémoires, Alphonse Humbert se place en observateur du bagne. En décrire la noirceur, la lourdeur administrative, les paradoxes et les absurdités, dépeindre les forçats dans leur complexité, leur monstruosité, leur honneur ou la richesse de leur langue, évoquer les rires et les joies aussi - même fugaces -, sont autant de facettes d'un récit remarquable qui, trente ans avant celui d'Albert Londres, dresse un réquisitoire implacable contre l'effroyable châtiment de l'exil
La biomasse alimentaire et forestière, une alternative pour l'élimination du chrome hexavalent dans des conditions naturelles
No full textInternational audienceOver the past decade, chromium pollution has garnered researchers' attention due to its harmful effects on ecosystems and human health. In New Caledonia, open-cast nickel mining contributes to the release of metals into waterways, especially chromium, including its carcinogenic form, chromium VI (Cr(VI)). Chromium concentrations in watercourses can exceed the 50µg/L threshold the World Health Organization recommends for drinking water quality. Plant biomass can be considered as an ecological and low-cost solution for mitigating the ecotoxicological and sanitary risks associated with chromium enrichment in watercourses. The DECHRO project, funded by the Foundation of the University of New Caledonia aims to investigate the ability of biomasses to limit the Cr(VI) concentrations under physicochemical conditions of watercourses. Various types of biomasses were tested, including three agricultural wastes (passion fruit peels, banana peels, and filtered coffee beans) and three forest biomasses (sawdust and bark from maritime pine and coconut fibers). Raw biomasses were characterized (pHz, FTIR, MEB, SEM) and then tested for 7 days in a solution whose pH, temperature and Cr(VI) initial concentration were parameterized (pH 7-8, T•C =25•C, 100µg/mL). Kinetics of Cr(VI) removal by biomasses were studied. Analyses combining ionic chromatography and inductively coupled plasma mass spectrometry (ICP-MS) provide a better understanding of the mechanism of chromium elimination in solution. Passion fruit peels and banana peels convert over 90% of Cr(VI), leading to the hypothesis of a direct Cr(VI) reduction mechanism into non-toxic Cr(III). These biomasses have been pre-treated to improve their ability to limit Cr(VI) in solution. SEM microscopy analysis revealed a general biomass structure particularly propitious to pollutant trapping. The molecular composition of each biomass plays a significant role towards Cr(VI). These results, obtained using ecological solutions under natural conditions, enable us to propose these plant biomasses as promising candidates for the implementation of biofilters to safely and sustainably trap toxic Cr(VI) in watercourses.Le projet DECHRO, financé par la Fondation de l'Université de Nouvelle-Calédonie, vise à étudier la capacité des biomasses à limiter les concentrations de Cr(VI) dans les conditions physico-chimiques des cours d'eau. Différents types de biomasses ont été évalués, dont trois déchets agricoles (écorces de fruit de la passion, pelures de banane et grains de café filtrés) et trois biomasses forestières (sciure et écorces de pin maritime et de fibres de coco). Les biomasses brutes ont été caractérisées (pHz, FTIR, MEB, MEB) puis testées pendant 7 jours dans une solution dont le pH, la température et la concentration initiale en Cr(VI) ont été paramétrés (pH 7-8, T◦C = 25◦C, 100 μg/mL). La cinétique d'élimination du Cr(VI) par les biomasses a été étudiée. Des analyses combinant chromatographie ionique et spectrométrie de masse à plasma inductif (ICP-MS) permettent de mieux comprendre le mécanisme d'élimination du chrome en solution
