HAL Portal UPF (Université de la Polynésie française)
Not a member yet
3802 research outputs found
Sort by
Potential of Marine Sponge Metabolites against Prions: Bromotyrosine Derivatives, a Family of Interest
No full textInternational audienceThe screening of 166 extracts from tropical marine organisms (invertebrates, macroalgae) and 3 cyclolipopeptides from microorganisms against yeast prions highlighted the potential of Verongiida sponges to prevent the propagation of prions. We isolated the known compounds purealidin Q (1), aplysamine-2 (2), pseudoceratinine A (3), aerophobin-2 (4), aplysamine-1 (5), and pseudoceratinine B (6) for the first time from the Wallisian sponge Suberea laboutei. We then tested compounds 1–6 and sixteen other bromotyrosine and bromophenol derivatives previously isolated from Verongiida sponges against yeast prions, demonstrating the potential of 1–3, 5, 6, aplyzanzine C (7), purealidin A (10), psammaplysenes D (11) and F (12), anomoian F (14), and N,N-dimethyldibromotyramine (15). Following biological tests on mammalian cells, we report here the identification of the hitherto unknown ability of the six bromotyrosine derivatives 1, 2, 5, 7, 11, and 14 of marine origin to reduce the spread of the PrPSc prion and the ability of compounds 1 and 2 to reduce endoplasmic reticulum stress. These two biological activities of these bromotyrosine derivatives are, to our knowledge, described here for the first time, offering a new therapeutic perspective for patients suffering from prion diseases that are presently untreatable and consequently fatal
Turtles for the ancestors: A zooarchaeological study of ritual deposits on Fakahina, Tuamotu archipelago (French Polynesia)
No full textInternational audienceRituals and feasting ceremonies at Polynesian marae depict culturally complex relationships between humans and animals that cannot be explained by subsistence alone. In Central‐East Polynesia, this topic still requires the elaboration of a “ritual zooarchaeology” framework. Using sea turtle assemblages from three sacred sites on Fakahina atoll (Tuamotu), this study offers a preliminary approach to faunal deposits from ritual contexts. Following systematic excavations of marae on Fakahina, analysis aimed to determine whether faunal deposits could be linked with intentional feasting and offering behaviours. To detect how ritual actions were organised through space, skeletal and taphonomic variables were examined for both overall sites and “sub‐assemblages” within sites based on the spatial associations of fauna with site features. At certain site features, derived quantitative units such as %MAU and recovery rate could identify potential offering behaviours through the intentional sorting of culturally significant body parts. The taphonomic signatures of site features could also identify open or closed deposition environments, assisting with the identification of disturbed features as either exposed platforms or enclosed cists. In addition to highlighting previously undocumented complexity in the use of site features, an overall comparison of turtle remains from the three sites shows the potential of these methods to explore variation in ritual practices.Les rituels et festins cérémoniels conduits sur les marae polynésiens reflètent des relations hommes‐animaux complexes dépassant le cadre de la simple subsistance. Néanmoins, ce sujet de recherche en Polynésie centre‐orientale requiert l’élaboration d'un cadre d'analyse, autrement dit une “archéozoologie du rituel.” Se basant sur des assemblages de tortues de trois sites sacrés sur l'atoll de Fakahina (archipel des Tuamotu), cette étude cherche à déterminer si les dépôts fauniques peuvent être mis en rapport avec des comportements de consommation cérémonielle ou d'offrandes. Afin de reconstituer l'organisation spatiale des actions rituelles, nous examinons les variations squelettiques et taphonomiques aux échelles inter et intra‐sites. Dans certaines structures, les analyses quantitatives ( Minimal Animal Unit, Recovery rate ) ont permis d'identifier des comportements rituels au travers du dépôt intentionnel de parties importantes de l'animal. Les signatures taphonomiques contribuent également à distinguer des environnements de dépôt ouverts ou fermés. Cette étude révèle non seulement une complexité de gestes jusqu’à présent pas documentés archéologiquement, mais aussi le potentiel de notre approche pour explorer les variations de pratiques rituelles entre sites
Le renouvellement des conditions d'implantation des casinos : d'une exception à un tournant systémique
No full textInternational audienc
Un nouveau PGD : l'obligation pour l'employeur de s'assurer que les mutations ne portent pas une atteinte injustifiée ou disproportionnée à la vie personnelle et familiale
No full textInternational audienceNote sous CE 4 janvier 2024, no 466189 (Lebon T.), Comité social et économique central de l'Agence française de développement (CSEC AFD
Educational policies vs neuroscience. The strange case of Overseas France
No full textInternational audienceStarting from the 2000s, educational policies in France have suddenly integrated neuroscience and artificial intelligence and the different governments that have alternated in these two decades have created many consultative bodies to implement in public action the results of research in these two areas. The declared objective of those responsible for the education system was to improve the performance of French students, whose weaknesses have been highlighted by various comparative studies (such as PISA). Nonetheless, a relevant corpus of research has shown that the measures implemented not only do not take research data into consideration (and are limited to a folkloric use of AI) but also that they do not contribute to solving the most serious structural problems (the degradation of the school climate and the dissatisfaction of teachers), especially in the most marginalized, peripheral and isolated contexts, such as overseas territories. This communication presents some considerations regarding this inconsistency and the catastrophic effects it has had on ultramarine youth, contributing, indirectly, to increasing school dropouts and conflicts between students, teachers, and parents (and, more prosaically, to squandering public money).A partire dagli anni 2000, le politiche educative in Francia hanno repentinamente integrato le neuroscienze e l’intelligenza artificiale e i differenti governi che si sono alternati in questi due decenni hanno creato un gran numero di istanze di carattere consultivo per implementare i risultati della ricerca in questi due ambiti nell’azione pubblica. L’obiettivo dichiarato dai responsabili del sistema educativo è stato quello di migliorare la performance degli studenti francesi, le cui debolezze sono state messe in evidenza da vari studi comparativi (come PISA). Ciononostante, numerose ricerche hanno mostrato che le misure messe in atto non solo non prendono in considerazione i risultati della ricerca (e che si limitano a un uso folklorico dell’IA) ma anche che non contribuiscono a risolvere i problemi strutturali più gravi (la degradazione del clima scolastico e l’insoddisfazione dei docenti), soprattutto nei contesti più marginalizzati, periferici ed isolati, come lo sono i territori d’oltremare. Questa comunicazione presenta alcune considerazioni a proposito di tale incongruenza e degli effetti catastrofici che ha avuto sulla gioventù ultramarina, contribuendo, indirettamente, ad aumentare l’abbandono scolastico e i conflitti tra studenti, docenti e genitori (e, più prosaicamente, a sperperare il denaro pubblico)
French coastal network for carbonate system monitoring: the CocoriCO2 dataset
No full textInternational audienceSince the beginning of the industrial revolution, atmospheric carbon dioxide (CO2) concentrations have risen steadily and have induced a decrease of the averaged surface ocean pH by 0.1 units, corresponding to an increase in ocean acidity of about 30 %. In addition to ocean warming, ocean acidification poses a tremendous challenge to some marine organisms, especially calcifiers. The need for long-term oceanic observations of pH and temperature is a key element to assess the vulnerability of marine communities and ecosystems to these pressures. Nearshore productive environments, where a large majority of shellfish farming activities are conducted, are known to present pH levels as well as amplitudes of daily and seasonal variations that are much larger than those observed in the open ocean. Yet, to date, there are very few coastal observation sites where these parameters are measured simultaneously and at high frequency. To bridge this gap, an observation network was initiated in 2021 in the framework of the CocoriCO2 project. Six sites were selected along the French Atlantic and Mediterranean coastlines based on their importance in terms of shellfish production and the presence of high- and low-frequency monitoring activities. At each site, autonomous pH sensors were deployed, both inside and outside shellfish production areas, next to high-frequency CTD (conductivity–temperature–depth) probes operated through two operating monitoring networks. pH sensors were set to an acquisition rate of 15 min, and discrete seawater samples were collected biweekly in order to control the quality of pH data (laboratory spectrophotometric measurements) as well as to measure total alkalinity and dissolved inorganic carbon concentrations for full characterization of the carbonate system. While this network has been up and running for more than 2 years, the acquired dataset has already revealed important differences in terms of pH variations between monitored sites related to the influence of diverse processes (freshwater inputs, tides, temperature, biological processes). Data are available at https://doi.org/10.17882/96982 (Petton et al., 2023a)
Intrinsic Versus Wind‐Forced Great Whirl Non‐Seasonal Variability
No full textInternational audienceThe Great Whirl (GW) is a quasi‐permanent anticyclonic eddy that appears every summer monsoon offshore of the Somalia upwelling. The annual cycle of the GW is well described, but deviations from its mean seasonal cycle (hereafter non‐seasonal variability) have been less explored. Satellite observations reveal that the leading mode of summer non‐seasonal sea‐level variability in this region is associated with ∼100‐ km northward or southward GW shifts from its climatological position. Northward shifts are associated with a stronger GW, and two cold, productive coastal upwelling wedges at 5°N and 10°N. Southward shifts are associated with a weaker GW, no wedge at 5°N and a single stronger‐than‐usual cold and productive wedge at 10°N. An eddy‐permitting (25‐km resolution) 50‐member ensemble ocean simulation reproduces this GW variability well. It indicates that the non‐seasonal GW variability has a short ∼20 days timescale intrinsic component, associated with the GW interaction with mesoscale eddies, and a lower‐frequency, ∼100 days externally forced component. Intrinsic variability dominates at both subseasonal (two thirds of the variance) and interannual timescales (57% of the variance). The externally forced signal results from shifts in the probability distribution of the subseasonal GW position (e.g., more likely northward than southward shifted instantaneous GW positions over a season). The mechanism for this external forcing is not entirely clear, but it appears to be related to the Rossby wave response to offshore wind stress curl forcing, which evolves into a north‐south dipole that projects onto the GW variability pattern
Exploring global accessibility of deep ocean water for sea water air conditioning (SWAC) process: Identifying feasibility areas depending on temperature source
No full textInternational audienceSea Water Air Conditioning (SWAC) technology is a highly efficient alternative to conventional air conditioning system using renewable marine energy to provide cooling to buildings. However, its implementation requires access to Deep Ocean Water (DOW) at 4-5 • C, thus SWAC is only viable in coastal regions. Furthermore, one of the major obstacles to its global development is the investment cost that remains high. This cost is strongly linked to the bathymetry of the installation location as it determines the length of the drawing pipeline, which accounts for the largest share of the investment cost. Knowing the temperature and bathymetry profiles will enable the establishment of the financial viability of SWAC technology in a specific location. This paper presents an analysis identifying areas of feasibility on a worldwide scale for standard SWAC implementation first. Then, it explores an alternative design with a higher drawing point for seawater at 12 • C (coupled with a High Temperature District Cooling), which reduces the cost by shortening the drawing pipeline and allows for more locations to be suitable for this technology. Additionally, the impact of the El Niño/Southern Oscillation (ENSO) is also considered since a shallower drawing point makes it more sensitive to temperature variations
Investigating the optimum density of plantation of noble Saccharum Officinarum canes under certified organic context using leaf area index
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/611443/)International audienceNoble sugarcanes are used in several cases of rum production and have a specific agronomic behavior as their morphologic characteristics are different from those observed in modern cultivars. Their height and tillering don't allow good yields under conventional methods of cultivation. They produce less stalks than modern cultivars on the same plant. Therefore, to get the same quantity of stalks per unit of surface, the population density has to be changed from standards. To study the impact of different densities on the cultivation of noble canes, the leaf area index (LAI) of noble and modern varieties was measured to know their capacity to cover the soil and prevent weed development. The cultivar To re'are'a (S. officinarum noble variety) was used with good agronomic potential, on an experimental plot of 4 000 m2 where two densities of plantation from 20 000 to 40 000 plant per hectare were compared, under the same cultivation standards. The doubled density plots showed better LAI (4,52 compared to 2,25 for low density), which increased month after month. Indeed, biomass yields were also higher (108,0 compared to 47,5 t/ha for the low density). Doubling the density of this noble cane could be a good agronomic practice to explore some better schemes of cultivation, adapted to organic agriculture. A special focus will be put on an intergeneric hybrid of Saccharum officinarum x Miscanthus floridulus called To 'a'eho (LAI = 6,65) to investigate the management of weeds inside the row