Journal of Next-Generation Research 5.0
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Dynamique du français au Cameroun
No full textBy its leading position in the sociolinguistic hierarchy of Cameroon, french has three essential functions: social control, vehicular and identity functions, which correspond to institutional regulations, social regulations and cultural regulations, three external forces that pushed the co-official language to become a language of Cameroonian culture. The social control function enables one to observe that french acquired a vitality that ensures its expansion and perpetuates its use. Social control presupposes the struggle against cultural alienation and the promotion of official languages in order to forge centripetal linguistic behavior. Cameroon chooses a solution that combines french, english and local languages and cultures. This solution enhances the process of indigenization of french which started in the early days of the twentieth century. The vehicular function enables one to observe that french language consolidates, in the independent state, its vehicular language status, which allows it to increase the number of its speakers and its functions, especially successful exchanges between the various communities in Cameroon and the dialogue between local cultures. The identity function shows that french has become a language of Cameroonian culture. It plays an integration role by breaking the language borders that national languages erect between the many Cameroonian communities. The institutional regulations, social regulations and cultural regulations are seen as external forces that exert on the french language the pressure that led her to “camerounise” thus undergoing structural regulations. Many varieties of french have been reported in Cameroon, but despite the existence of these varieties, a common language has developed, which is recognizable by its phonetic peculiarities, morphosyntactic peculiarities and lexical creation processes that enable the common language to be established in Cameroon's socio-cultural context. This language, which claims unanimity and that can be codified, assumes another function : the unifying function that is both linguistic and political.Grâce à sa dynamique, le français assume trois fonctions essentielles au Cameroun : la fonction de contrôle social, la fonction véhiculaire et la fonction identitaire. Ces fonctions correspondent, respectivement, aux régulations institutionnelles, aux régulations sociales et aux régulations culturelles, perçues comme des forces externes qui ont poussé la langue co-officielle à se restructurer pour devenir une langue de culture camerounaise. La fonction de contrôle social laisse observer que le français a acquis une vitalité qui assure son expansion et pérennise son usage. Le contrôle social suppose la lutte contre l’aliénation culturelle et la promotion des langues officielles pour forger des comportements linguistiques centripètes. Le Cameroun choisit, pour ce faire, une solution qui fusionne les langues des anciennes métropoles et les cultures locales. Cette solution renforce le processus d’endogénéisation du français amorcé dès les débuts de la francisation. Avec la fonction véhiculaire, l’on perçoit que la langue française consolide, dans l’État indépendant, son statut de langue véhiculaire. Sa véhicularité, qui lui permet d’augmenter le nombre de ses locuteurs et de ses fonctions, facilite les échanges réussis entre les diverses communautés locales et le dialogue entre les cultures endogènes. La fonction identitaire montre que le français est devenu une langue de culture camerounaise. Elle joue le rôle de langue d’intégration en brisant les frontières que les langues nationales érigent entre les nombreuses communautés locales. Les régulations institutionnelles, les régulations sociales et les régulations culturelles se présentent comme des forces externes qui ont exercé sur la langue française la pression qui l’a amenée à se camerouniser, subissant ainsi des régulations structurelles. De nombreuses variétés de français ont été signalées au Cameroun, mais malgré l’existence de ces variétés, il s’est développé une langue commune reconnaissable à ses particularités phonétiques, morphosyntaxiques et à des processus de création lexicale qui permettent l’ancrage de la langue commune dans le contexte socioculturel camerounais. Cette langue, qui fait l’unanimité et qui peut être codifiée, assume une autre fonction : la fonction d’unification qui est à la fois linguistique et politique
An den Grenzen der Sinne: Zur Darstellung radioaktiver Strahlung in westdeutschen und US-amerikanischen Science-Fiction-Texten
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Oxygen and Carbon Stable Isotope Composition of Cretaceous to Pliocene Calcareous Paleosols in the Tian Shan Region (Central Asia): Controlling Factors and Paleogeographic Implications
No full textInternational audienceThe Late Mesozoic–Cenozoic topographic and climate evolution of Central Asia remains highly debated. The final retreat of the proto-Paratethys Sea from the western Tarim Basin is thought to correspond in time with the onset of tectonic uplift in the Pamir, Tian Shan and Altai ranges, as well as with regional aridification. The oxygen and carbon isotope compositions of the sediment deposits in the various Central Asian basins have already been used to decipher both the topographic and climatic changes that occurred in that region during the Cenozoic, generally concentrating on one sedimentary section and/or on a limited time range and either using multiple-type samples including sandstone calcitic cements, marine carbonates, fossils, or paleosols. In order to get a homogeneous dataset, minimizing variations in the isotopic composition of the material depending on its type and/or depositional environment, we selected only calcareous paleosols sampled in several continuous sections covering a wide time range from the Late Jurassic to the Pliocene. Our sampling also covers a wide area encompassing the whole Tian Shan region, which allows detecting regional variations in the δ 18 O and δ 13 C values. We show that the influence of the distance to the proto-Paratethys Sea on the paleosol δ 18 O record was not significant. Besides local factors such as the occurrence of large lakes that can have a significant effect on the isotopic composition of the calcareous paleosols, the long-term evolution of both the δ 18 O and δ 13 C values possibly reflects the hypsometry of the river drainage systems that bring water to the basins. However, as it is commonly accepted that the δ 18 O of soil carbonates is controlled by the δ 18 O of in-situ precipitation, this last conclusion remains to be further investigated
Antiplasmodial, Anti-chikungunya virus and Antioxidant Activities of 64 endemic Plants from the Mascarene Islands
No full textInternational audienceVector-borne diseases cause more than 1 million deaths annually. The research of new medicines is urgent, especially since there is currently no specific treatment. In this study, the authors have selected 64 endemic plants from the Mascarene Islands based on their endemism, their medicinal use and their registration in the French Pharmacopeia to evaluate the antiplasmodial, anti-chikungunya and antioxidant activities. The list of these 64 plants including their local name, population, data of collection and voucher number are available in the Supporting Information section. 40 active extracts have been identified from the 38 species: 22 responded positively to the antiplasmodial activity, 8 to the anti-chikungunya activity and 8 to the antioxidant activity.Six plants demonstrated high antiplasmodial activity (IC50 2000 µM of Trolox equivalent per mg/mL of extract: Bertiera borbonica, Erythroxylon laurifolium, Erythroxylon sideroxyloides, Indigofera ammoxylum, Poupartia borbonica, Scolopia heterophylla, Sophora denudata, and Terminalia bentzoe. Some data obtained tend to corroborate with the reported traditional use of the plant, such as Zanthoxylum heterophyllum (antiplasmodial), Aphloia theiformis (anti-chikungunya), and Erythroxylon laurifolium (antioxidant)
An individual based model to optimize natural enemies deployment in augmentative biological control.
No full textInternational audienceAugmentative biological control is a crop protection method that relies on the repeated introduction of natural enemies to fight agricultural crop pests. The question of the amount, distribution and frequency of natural enemies introductions to best suppress the pests is a central issue. Mathematical results were obtained with hybrid population dynamics models. They indicate that the optimal deployment strategy of natural enemies strongly relies on the presence [4] and sign of density dependence among the natural enemies population [5, 6, 1], and is also affected by the spatial structure of the environment [3]. To evaluate these theoretical predictions in a more realistic, stochastic and spatially explicit setting, a stochastic individual based model has been built on the multi-agent programmable modeling environment Netlogo [7]. Extensive simulatory experiments were performed to assess the effects of density dependent processes as well as spatial structure and stochasticity on augmentative biological control performance and variability. In addition to being used to optimise biological control agents introductions, the model has also been designed to ease the communication with a non-specialist audience regarding the effects of complex population dynamics processes on augmentative biological control efficacy and optimal natural enemies deployment strategies. This objective ressembles that of the Webidemics model in plant epidemics control [2].References[1] N. Bajeux, F. Grognard, and L. Mailleret. Augmentative biological control when the natural enemies are subject to Allee effects. Journal of Mathematical Biology, Vol 47-1, pp 1561-1587, 2017.[2] N.J. Cunniffe , R.O.J.H. Stutt, R.E. DeSimone, T.R. Gottwald, C.A. Gilligan. Optimising and communicating options for the control of invasive plant disease when there is epidemiological uncertainty. PLoS Computational Biology, 2015.[3] B. Ghosh, F. Grognard and L. Mailleret. Natural enemies deployment in patchy environments for augmentative biological control. Applied Mathematics and Computations, Vol. 266, pp. 982-999, 2015.[4] L. Mailleret and F. Grognard. Global stability and optimisation of a general impulsive biological control model. Mathematical Biosciences, Vol. 221-2, pp. 91-100, 2009.[5] S. Nundloll, L. Mailleret and F. Grognard. Influence of intrapredatory interferences on impulsive biological control efficiency. Bulletin of Mathematical Biology, Vol. 72-8, pp. 2113-2138, 2010.[6] S. Nundloll, L. Mailleret and F. Grognard. Two models of interfering predators in impulsive biological control. Journal of Biological Dynamics, Vol. 4, pp. 102-114, 2010.[7] U. Wilensky, 1999. NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University. Evanston, IL
Distribution, redox state and (bio)geochemical implications of arsenic in present day microbialites of Laguna Brava, Salar de Atacama
No full textInternational audienceUnderstanding how microorganisms adapted to the high arsenic concentration present on early Earth requires understanding of the processes involved in the arsenic biogeochemical cycle operating in living microbial mats. To this end, we investigated a living microbial mat from Laguna Brava (Salar de Atacama, Chile), a hypersaline lake with high arsenic concentration, using an array of conventional geochemical techniques, such as X-ray diffraction, SEM-EDX and Confocal Laser Scanning Microscopy (CLSM), combined with state-of-the-art high resolution scanning imaging techniques, including X-ray micro-fluorescence (μXRF) and X-ray Absorption Near Edge Structure (XANES) mapping. This experimental approach allowed us to unravel the relationship between the microbial mat activity, mineral occurrence, arsenic speciation, distribution of major and trace elements and their relationship with the mineralogy and the exopolymeric substances (EPS). We show that As was not linked to Ca or Si, and only moderately related to Fe, resulting from sorption onto an iron (oxy)hydroxide mineral. In addition, we were able to identify organic-rich globules containing significant As but no other trace metal(loid)s, and determine the co-existence of As(III) and As(V). These observations strongly support the occurrence of microbially-mediated arsenic cycling in these microbial mats
Dinâmica da paisagem em planícies de inundação amazônicas: o caso do Lago Grande do Curuai, Pará, Brasil.
No full textInternational audienceFloodplains in the Amazon are areas of great economic, social and ecological importance. Occupation in these areas brings various impacts due to its complexity and fragility. This paper aims to analyze dynamics of change in land use and land cover in the floodplain of Lago Grande do Curuai, near Santarém city, in the state of Pará. To that end, geotechnologies associated with landscape metrics and an analysis of two different geographic clippings of the region were used. The first geographic clipping covers the entire hydrographic basin, focusing on the analysis of the natural vegetation cover (dryland and lowlands); the second geographic clipping shows the area divided in six landscape zones, whose criteria are the productive systems and the characteristics of use of the region. We classified images from satellites Landsat 5 and 7 from the years 1985, 1997 and 2014. Landscape metrics established patterns that facilitated the comparison between different times. In the first geographic clipping, metrics show a moderate dynamic in the period. Although there is a decrease in dry land forest areas, the class in which there is greater increase is the secondary/"capoeira" vegetation. There are increases in the pasture areas, the farmlands, however, remain stable; pasture and farming areas occur in a dispersed way in the territory and in small allotments; this dynamic revealed by classification indicates that cultivation areas are occupied by rotation, being occupied and abandoned over time. In the second geographic clipping, zones 3 and 4 concentrate most of the processes ofreplacing the natural vegetation cover by anthropic activities. The analysis in different geographic clippings shows the researched area has heterogeneous patterns of occupation in time and space.Les bassins d’inondation amazoniens sont de grande valeur économique, sociale et écologique. Ces espaces complexes et fragiles sont confrontés à une grande diversité d’usage. Cette recherche analyse la dynamique de changement de l’occupation du sol dans le bassin d’inondation du Lac Grand do Curuai, à proximité de Santarém (État du Pará). Pour cela, des métriques paysagères ont été calculées dans deux zonages préalablement sélectionnés afin d’affiner l’analyse des changements spatio-temporels. D’une part les traitements ont porté sur l’ensemble du bassin versant afin d’appréhender les différents types de végétation naturelle (forêt de varzea et forêt de terre ferme). D’autre part, il s’est agit d’effectuer les calculs dans un zonage paysager qui exprime la diversité des systèmes agricoles associés aux caractéristiques environnementales de la région. Les images de satellites utilisées (Landsat 5 et Landsat 7) permettent de conduire l’analyse sur 3 périodes : 1985, 1997 et 2014. Les métriques paysagères ont aidé à établir un modèle paysager qui a pour fonction la comparaison dans le temps et dans l’espace. Les calculs effectués dans le premier zonage expriment une dynamique d’évolution modérée. Si la classe de « forêt de terre ferme » diminue, celles de « végétation secondaire» et de « pâturage » augmentent en superficie. En revanche, la classe « parcelle de manioc » reste stable. Ces classes dispersées dans la zone d’étude, sont de petite taille et changent d’emplacement d’une période sur l’autre. Cette répartition et ces changements sont le signe d’un usage rotationnel des terres. Le deuxième niveau de zonage montre que ces évolutions rotationnels ont essentiellement lieu dans deux des paysages les plus anthropisés. Les dynamiques des autres paysages augurent des modifications d’usage des milieux. L'analyse basée sur ces deux types de zonages permet de mieux affiner les hétérogénéités spatiales dans le temps et dans l'espace.As planícies de inundação amazônicas são áreas de grande importância econômica, social e ecológica. A ocupação desses ambientes complexos e frágeis traz variados impactos. Esse estudo pretende analisar dinâmicas de alteração de uso e cobertura da terra em uma região de planície de inundação, próximo a cidade de Santarém (PA), sendo a bacia hidrográfica do Lago Grande do Curuai o foco da pesquisa. Para isso foram utilizadas geotecnologias associadas à métricas de paisagens, e uma análise a partir de dois recortes geográficos distintos na mesma área de estudo. O primeiro recorte geográfico é equivalente a toda a bacia hidrográfica, tendo foco na análise da cobertura vegetal natural, correspondente as florestas de terra firme e de várzea; o segundo recorte diz respeito a divisão da área de estudo em seis zonas de paisagem, sendo que essa divisão levou em conta os sistemas produtivos e as características de uso da região em sua delimitação. Foram classificadas imagens dos satélites Landsat 5 e 7, dos anos de 1985, 1997 e 2014. As métricas de paisagem permitiram estabelecer padrões da paisagem, facilitando a comparação entre os momentos distintos. No primeiro recorte, as métricas apontam para uma dinâmica moderada no período; embora haja uma diminuição das áreas de floresta de terra firme, a classe em que há maior aumento é a de vegetação secundária/capoeira. Ocorrem aumentos das áreas de pastagem, entretanto as áreas de cultivo de roça mantêm-se estáveis. As áreas de pasto e roça ocorrem de forma dispersa no território e em pequenas parcelas; essa dinâmica apontada pela classificação é um indicativo de que as áreas de cultivo ocorrem de forma rotacionada, com a ocupação de áreas diferentes que vão se recuperando com o passar do tempo. No segundo recorte, dentre as seis zonas da paisagem, duas são concentradoras de grande parte dos processos de substituição da cobertura vegetal natural por atividades antrópicas, sendo as zonas 3 e 4 as que tem mais alteração da paisagem. A análise em recortes geográficos distintos permitiu identificar que a área de estudo possui padrões heterogêneos de ocupação no tempo e no espaço
The physical and qualitative analysis of fluctuations in air and vapour concentrations in a porous medium
No full textInternational audienceThis work presents the development and physical analysis of a sweat transport model that couples the fluctuations in air and vapour concentrations, and temperature, in a one-dimensional porous clothing assembly. The clothing is exposed to inherent time-varying conditions due to variations in the body temperature and ambient conditions. These fluctuations are governed by a coupled system of nonlinear relaxation–transport–diffusion PDEs of Petrovskii parabolic type. A condition for the well-posedness of the resulting system of equations is derived. It is shown that the energy of the diffusion part of the system is exponentially decreasing. The boundedness and stability of the system of equations is thus confirmed. The variational formulation of the system is derived, and the existence and uniqueness of a weak solution is demonstrated analytically. This system is shown to conserve positivity. The difficulty of obtaining an analytical solution due to the complexity of the problem, urges for a numerical approach. A comparison of three cases is made using the Crank–Nicolson finite difference method (FDM). Numerical experiments show the existence of singular coefficient matrices at the site of phase change. Furthermore, the steady-state profiles of temperature, air and vapour concentrations influence the attenuation of fluctuations. Numerical results verify the analytical findings of this work
A new paradigm for δ 18 O in coral skeleton oxygen isotope fractionation response to biological kinetic effects
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L'Habitabilité territoriale par une approche prospective
No full textInternational audienceLa littérature contemporaine s’intéresse à des segments de l’habitabilité territoriale comme en témoignent les études. Cet intérêt a pour objet d’améliorer ou de résoudre prioritairement certaines contraintes. Cependant, convaincus que toute étude ne peut se réduire à un objectif unique et à des indicateurs limités, celle de l’habitabilité territoriale ne peut prétendre à cette économie.Cette communication a pour ambition présenter des analyseurs ou variables liés à l’étude de l’habitabilité territoriale en mettant en lumière des prérequis, comme des éléments propédeutiques à une analyse prospective issue de propositions de différents scenarii.Le traitement des données empiriques selon la « Théorie Enracinée ou Ancrée » a permis l’extraction d’une dizaine de variables. Ensuite une modélisation des grandeurs structurantes et impactantes selon le Modèle COSCEVO nous a permis de dégager des scénarii.En résulte de ces processus, que dans l’habitabilité territoriale par une approche prospective, une utilité multifonctionnelle peut se manifester, à savoir : un outil au service de politiques sociales et économiques, un moyen d'élaborer un projet tant collectif que communautaire, non sans débats des acteurs locaux