Journal of Next-Generation Research 5.0
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Préface - Thirukkural, Éthique et Représentations, la Vertu, la Fortune et l'Amour
No full textInternational audienceThis volume reproduces the proceedings of the International Conference of Asies/Croima, Inalco (Paris), University of La Reunion, April 14, 15, 16, 2016. This conference about Thirukkural has been initiated by Dr Selvam Chanemougame, President of Tamij Sangam, and directed by the cultural anthropologist Dr Florence Callandre-Barat, Senior Lecturer in University of La Reunion.Ce volume reunit les actes du colloque international d'Asies/Croima, de l'Inalco (Paris) qui s'est tenu a l'Universite de La Reunion les 14, 15, 16 avril 2016. Ce colloque sur le Thirukkural a ete initie par Dr Selvam Chanemougame, President de Tamij Sangam et dirige par le docteur en anthropologie Florence Callandre-Barat, Maitre de conferences a l'Universite de La Reunion
Qui vend à qui dans le périurbain ? L'inflation des prix résidentiels et la dynamique vendeurs-acquéreurs dans la région métropolitaine de Paris, 1996-2012
No full textReceived: July 17, 2018; Accepted: February 16, 2019; Published: March 21, 2019International audiencePrice inflation has outbalanced the income of residents and buyers in major post-industrial city-regions, and real estate has become an important driver of these inequalities. In a context of a resilient inflation of home values during the last two decades in the greater Paris Region, it is critical to examine housing price dynamics to get a better understanding of socioeconomic segregation. This paper aims at presenting spatial analysis of the dynamics of segregation pertaining to inflation, analyzing price and sellers and buyers data. Using interpolation techniques and multivariate analysis, the paper presents a spatial analysis of property-level data from the Paris Chamber of Notaries (1996-2012) in a GIS (159,000 transactions in suburban areas, single family homes only). Multivariate analysis capture price change and local trajectories of occupational status, i.e. changes in balance between inward and outward flows of sellers and buyers. We adopt a method that fits the fragmented spatial patterns of suburbanization. To do so, we remove the spatial bias by means of a regular 1-km spatial grid, interpolating the variables within it, using a time-distance matrix. The main results are threefold. We document the spatial patterns of professionalization (a rise of executives, intermediate occupation and employees) to describe the main trends of inward mobility in property ownership in suburbs, offsetting the outward mobility of retired persons. Second, neighborhood trajectories are related the diverging patterns of appreciation, between local contexts of accumulation with a growth of residential prices, and suburbs with declining trends. The maturity of suburbanization yields a diversified structure of segregation between the social groups, that do not simply oppose executives vs. blue collar suburbs. A follow-up research agenda is finally outlined.L'inflation immobilière est devenue un facteur essentiel des inégalités : la hausse des prix a en effet été plus rapide que celle des revenus dans la plupart des métropoles post-industrielles. Dans un contexte d'inflation continue des valeurs immobilières depuis deux décennies dans la région Ile-de-France, l'analyse des dynamiques des prix immobiliers vise à mieux saisir les processus de ségrégation socioéconomique.L'article propose une analyse spatiale des dynamiques de ségrégation résultantes de cette inflation, en analysant les prix et les données sur les acquéreurs et les vendeurs. A partir d'interpolations et d'analyses multivariées, on présente une analyse spatiale des données des transactions de la Chambre des Notaires (1996-2012): 159,000 transactions dans le périurbain, pour les maisons individuelles, sont analysées. Sont analysées la dynamique spatiale des prix, ainsi que les trajectoires locales socio-professionnelles des acquéreurs-vendeurs, c'est-à-dire le solde entre le nombre d'acquéreurs et de vendeurs par catégorie socioprofessionnelle. La méthode vise une cohérence avec la structure spatiale fragmentée du périurbain : afin de neutraliser les biais (MAUP), on utilise une grille de 1 km pour l'interpolation des variables, et celle-ci repose sur une matrice des distances-temps.Les résultats sont de trois ordres. D'une part, la dynamique de professionnalisation (solde positif de CPIS, professions intermédiaires et employés) explique la structure spatiale de l'accession et de l'achat dans le périurbain, les retraités étant plutôt vendeurs et sortant du marché. D'autre part, l'inflation des prix se traduit par des dynamiques divergentes, entre des contextes d'appréciation et d'accumulation ; et des contextes locaux de dépréciation relative, critiques pour les propriétaires. Enfin, la maturité de la périurbanisation produit des formes d'appariement variées, qui ne reposent pas sur l'opposition cadres-ouvriers, mais sur une grande diversité des contextes. L'exposé d'agenda de recherche conclut la contribution.Inégalités spatiales; ségrégation; parcours résidentiel ; marché immobilier, financiarisation et ; accession à la propriété; Analyse de données géoréférencées; SIG; Enquête statistiq par questionnaire sondage ;; ; ;, ;; ; ; GIS; ; trajectories of households; ; surve
L’exil de Ranavalona III ou la construction de l’image d’une reine d’opérette
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Numerical simulation of surface solar radiation over Southern Africa. Part 1: evaluation of regional and global climate models.
No full text21 pagesInternational audienceThis study evaluates the performance of climate models in reproducing surface solar radiation (SSR) over Southern Africa (SA) by validating five Regional Climate Models (RCM, including CCLM4, HIRHAM5, RACMO22T, RCA4 and REMO2009) that participated in the Coordinated Regional Downscaling Experiment program over Africa (CORDEX-Africa) along with their ten driving General Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 over SA. The model simulated SSR was thereby compared to reference data from ground-based measurements, satellite-derived products and reanalyses over the period 1990–2005. Results show that (1) the references obtained from satellite retrievals and reanalyses overall overestimate SSR by up to 10 W/m2 on average when compared to ground-based measurements from the Global Energy Balance Archive, which are located mainly over the eastern part of the southern African continent. (2) Compared to one of the satellite products (Surface Solar Radiation Data Set—Heliosat Edition 2; SARAH-2): GCMs overestimate SSR over SA in terms of their multi-model mean by about 1 W/m2 (compensation of opposite biases over sub-regions) and 7.5 W/m2 in austral summer and winter respectively; RCMs driven by GCMs show in their multimodel mean underestimations of SSR in both seasons with Mean Bias Errors (MBEs) of about − 30 W/m2 in austral summer and about − 14 W/m2 in winter compared to SARAH-2. This multi-model mean low bias is dominated by the simulations of the CCLM4, with negative biases up to − 76 W/m2 in summer and − 32 W/m2 in winter. (3) The discrepancies in the simulated SSR over SA are larger in the RCMs than in the GCMs. (4) In terms of trend during the “brightening” period 1990–2005, both GCMs and RCMs (driven by European Centre for Medium-Range Weather Forecasts Reanalysis ERA-Interim, short as ERAINT and GCMs) simulate an SSR trend of less than 1 W/m2 per decade. However, variations of SSR trend exist among different references data. (5) For individual RCM models, their SSR bias fields seem rather insensitive with respect to the different lateral forcings provided by ERAINT and various GCMs, in line with previous findings over Europe. (6) Biases in SSR are overall qualitatively consistent with those in total cloud cover. The information obtained in present study is of crucial importance for understanding future climate projections of SSR and for relevant impact studies
Study on Temporal Variations of Surface Temperature and Rainfall at Conakry Airport, Guinea: 1960–2016
No full textInternational audienceThe monthly averaged data time series of temperatures and rainfall without interruption of Conakry Airport (9.34 • N 13.37 • W, Guinea) from 1960 to 2016 were used. Inter-annual and annual changes in temperature and rainfall were investigated. Then, different models: Mann-Kendall Test, Multi-Linear-Regression analysis, Theil-Sen's slope estimates and wavelet analysis where used for trend analysis and the dependency with these climate forcings. Results showed an increase in temperature with semi-annual and annual cycles. A sharp and abrupt rise in the temperature in 1998 was found. The results of study have shown increasing trends for temperature (about 0.21 • /year). A decrease in rainfall (about −8.14 mm/year) is found since the end of 1960s and annual cycle with a maximum value of about 1118.3 mm recorded in August in average. The coherence between the two parameters and climate indices: El Niño 3.4, Atlantic Meridional Mode, Tropical Northern Atlantic and Atlantic Niño, were investigated. Thus, there is a clear need for increased and integrated research efforts in climate parameters variations to improve knowledge in climate change
Numerical approximation of the 3d hydrostatic Navier-Stokes system with free surface
No full textInternational audienceIn this paper we propose a stable and robust strategy to approximate the 3d incompressible hydrostatic Euler and Navier-Stokes systems with free surface. Compared to shallow water approximation of the Navier-Stokes system, the idea is to use a Galerkin type approximation of the velocity field with piecewise constant basis functions in order to obtain an accurate description of the vertical profile of the horizontal velocity. Such a strategy has several advantages. It allows - to rewrite the Navier-Stokes equations under the form of a system of conservation lawswith source terms, - the easy handling of the free surface, which does not require moving meshes, - the possibility to take advantage of robust and accurate numerical techniques developed in extensive amount for Shallow Water type systems. Compared to previous works of some of the authors, the three dimensional case is studied in this paper. We show that the model admits a kinetic interpretation including the vertical exchanges terms, and we use this result to formulate a robust finite volume scheme for its numerical approximation. All the aspects of the discrete scheme (fluxes, boundary conditions,. . . ) are completely described and the stability properties of the proposed numerical scheme (well-balancing, positivity of the water depth,. . . ) are discussed. We validate the model and the discrete scheme with some numerical academic examples (3d non stationary analytical solutions) and illustratethe capability of the discrete model to reproduce realistic tsunami waves
Evaluation of 3-hydroxy fatty acids as a pH and temperature proxy in soils from temperate and tropical altitudinal gradients
No full textInternational audienceThree hydroxy (3-OH) fatty acids (FAs), containing 10 to 18 C and a hydroxyl group in third position are characteristic components of Gram-negative bacteria. These compounds were used previously to detect and quantify Gram-negative bacterial communities in various types of samples, from terrestrial, aquatic and atmospheric environments. The relative abundance of 3-OH FAs in soils was recently shown to vary with mean annual air temperature (MAAT) and pH in soils from Mt. Shennongjia (China). In the current study, the concentrations and abundances of 3-OH FAs were determined in soils from altitudinal transects under tropical and temperate climates: Mt. Rungwe (SW Tanzania) and Mt. Majella (Central Italy), respectively. The aim was to (i) examine and compare the distributions of 3-OH FAs in soils from different climatic zones and (ii) to investigate the potential of 3-OH FAs as temperature and pH proxies. When combined with previously published data, a moderate correlation (R2 0.62) between the summed iso and anteiso to the total amount of normal 3-OH FAs (RIAN index) and pH was obtained. We show that Gram-negative bacteria respond in the same way to temperature variations in soils from different latitudes, with a relative increase of the anteiso to normal 3-OH FA ratios of the C15 and C17 compounds (RAN15 and RAN17 indices, respectively) with decreasing temperature. Nevertheless, the intercepts of the relationships between RAN15 and MAAT are mountain-dependent, suggesting that regional calibrations may be required to use RAN15 as a temperature proxy. In contrast with RAN15, the statistical similarity of the local relationships between RAN17 and MAAT leads to a combined calibration (R2 0.60, residual mean error 5.1 °C) covering a wide range of temperature (ca. 0–25 °C). As 3-OH FAs seem well-preserved in sedimentary archives, this strengthens the potential of these compounds as a temperature and pH proxy for paleoreconstructions in terrestrial settings
Sociologie de la gouvernance en contexte de revitalisation de l'intégration sous-régionale en Afrique Centrale: analyse des effets de la coopération décentralisée transfrontalière en zone CEMAC
No full textBoltzmann Distribution of Sediment Transport
No full textInternational audienceThe coupling of sediment transport with the flow that drives it allows rivers to shape their own bed. Cross-stream fluxes of sediment play a crucial, yet poorly understood, role in this process. Here, we track particles in a laboratory flume to relate their statistical behavior to the self organization of the granular bed they make up. As they travel downstream, the transported grains wander randomly across the bed's surface, thus inducing cross-stream diffusion. The balance of diffusion and gravity results in a peculiar Boltzmann distribution, in which the bed's roughness plays the role of thermal fluctuations, while its surface forms the potential well that confines the sediment flux