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Analyzing urban landscapes through satellite data to predict abundance of Aedes mosquito breeding sites
No full textInternational audienceThe spread of mosquito-transmitted diseases such as dengue is a major public health issueworldwide. Aedes aegypti mosquitoes, one of the primary vectors for dengue, thrive in urbanenvironments and breed mainly in artificial and natural water containers. A betterunderstanding of the relationship between urban landscapes and potential breeding siteswould help mitigate the risks associated with these diseases. This study examines therelationship between urban landscape characteristics derived from remote sensing and theabundance and type of potential breeding sites in cities of French Guiana, South America,provided by the surveys carried out by the regional vector control service. A Multiple FactorAnalysis revealed variables associated with the abundance of breeding sites, including buildingarea, landscape form index, number of buildings, and texture indices. We obtained a good fitbetween predicted and observed values of breeding sites abundance using Random Forestmodels, with varying effectiveness depending on the type of breeding site. Since in-situbreeding site data were not specifically acquired for the purpose of this study, the datasetshowed some limitations. However, we were able to apply this model in areas whereentomological data were not available. This approach also has the potential to be used asinput in the modelling of mosquito dynamics. This research highlights the usefulness of urbancharacteristics based on satellite data for improving vector control strategies
DE L’AGRICULTURE AU BATI DANS LES PLAINES INONDABLES DE L’AGGLOMERATION D’ANTANANARIVO (MADAGASCAR) : FACTEURS ET PRATIQUES DES ACTEURS DE L’URBANISATION INFORMELLE
No full textIn the Antananarivo conurbation, which is made up of hills and plains, urbanisation was initially hilly. Today, urbanisation is increasingly spreading to the plains. It is taking place at the expense of agriculture, despite the risk of flooding and outside the rules imposed by master plan. In this context, at the scale of the territory and of the actors (builders and regulators), what factors explain the informal urbanisation of flood plains? This research in geography uses a mixed method, combining quantitative data (spatial analysis) and qualitative data (interviews). At the scale of the conurbation, urbanisation accelerated over the period 2017-2022, to the detriment of agricultural areas located on flood plains. The transition from farming to brick production, from farming to built-up areas, or the maintenance of farming, depends on the risk of flooding, the conditions of agricultural production, accessibility, the price of land and the control of embankments. Within these plains, the urban development rationale of the players depends on these same factors, but a better analysis of the land factor is possible at this scale. In addition to the price and accessibility of land, the methods of access to land, the rights held and the ways in which they are secured influence the right to build, the timing of building projects and the forms of urbanisation. However, these factors play out differently depending on the profiles of the players involved (household or companies). Urban development on these plains is not held back by town planning regulations. Analysis of the practices of builders and regulators highlights the discrepancy between town planning rules and the reality, the complexity of procedures and the frequent circumvention of rules, often associated with corruption. Representatives of the regulatory bodies relax and change the rules in order to formalise ex-post informal construction in unbuildable and flood-prone areas.Au sein de l’agglomération d’Antananarivo, composée de collines et de plaines, l’urbanisation était d’abord collinaire. Actuellement, l’urbanisation gagne de plus en plus les plaines. Elle se fait au détriment de l’agriculture, en dépit des risques d’inondations et en dehors des règles imposées par les plans d’urbanisme. Dans ce contexte, à l’échelle du territoire et à celle des acteurs (constructeurs et régulateurs), quels facteurs expliquent la dynamique d'urbanisation informelle des plaines agricoles inondables ? Cette recherche en géographie développe une méthode mixte, couplant des données quantitatives (analyse spatiale) et qualitatives (entretiens). A l’échelle de l’agglomération, l’urbanisation s’est en effet accélérée au cours de la période 2017 – 2022, et au détriment des espaces agricoles, situés dans les plaines inondables. Le passage de l’agriculture à la production de briques, de l’agriculture au bâti ou le maintien de l’agricole, dépendent des risques d’inondation, des conditions de production agricole, de l’accessibilité, du prix des parcelles et du contrôle des remblais. Au sein de ces plaines, les logiques d’urbanisation des acteurs dépendent de ces mêmes facteurs mais une meilleure analyse du facteur foncier est possible à cette échelle. Au-delà du prix et de l’accessibilité des parcelles, les modes d’accès à la terre, les droits détenus, et les modes de sécurisation pèsent sur le droit de bâtir, la temporalité du projet de construction et les formes d’urbanisation. Cependant, ces éléments jouent différemment selon les profils des acteurs (ménages ou entreprises). L’urbanisation de ces plaines n’est pas freinée par les régulations d’urbanisme. L’analyse des pratiques des acteurs constructeurs et régulateurs souligne le décalage entre les règles d’urbanisme et la réalité de terrain, la complexité des procédures et le contournement fréquent des règles, souvent associé à de la corruption. Les représentants des instances de régulation assouplissent ou changent les règles pour formaliser ex-post les constructions informelles situées dans les zones inconstructibles et inondables
Homemade Dry Manure Tea is Equivalent to Synthetic Fertilizer for the Growth and Nutrition of Spinach
No full textInternational audienceThis study evaluates the effect of homemade dry manure tea (HMT), a liquid organic fertilizer widely used in North Africaas an alternative to synthetic fertilizers. The main objective is to characterize a specific HMT formulation and to studyits effect on spinach growth at two different doses as compared with a synthetic fertilizer. HMT was applied to a spinachcrop under controlled conditions in comparison with a synthetic fertilizer, applied at equivalent concentrations of nitrogen(N), phosphorus (P) and potassium (K). The effects of both types of fertilizer were evaluated, focusing on plant biomass,leaf morphology and nutrient uptake. The results show that the dosage of HMT typically used in Tunisia produces effectscomparable to those of a synthetic fertilizer on spinach biomass, leaf morphology and aerial potassium uptake. However,a dose of HMT that was six times more concentrated in N, P and K than the farmers’ dose resulted in inhibitory effects onbiomass and leaf morphology, that were not observed with the equivalent high dose of synthetic fertilizer. The use of HMTat farmer’s doses could provide a viable, locally sourced and environmentally friendly alternative to synthetic fertilizers.However, future research should focus on characterizing the variability of HMT based on its preparation methods, as thisvariability could significantly influence the composition of HMT and consequently its effects on crops
Sénégal : la loi sur le domaine national, l'État et le marché : contradictions structurelles et résilience d'une législation originale
No full text60 ans après sa promulgation, la Loi sur le domaine national (LDN) du Sénégal de 1964 continue de susciter des débats enflammés et des controverses vives. Véritable monument, la LDN est au coeur des débats sur la politique foncière au Sénégal, critiquée pour son inadaptation à une économie de marché et pour sa faible application, mais aussi défendue face aux pressions à la privatisation. En interrogeant dans une perspective de sociologie historique du droit les rapports complexes et controversés entre le Domaine national, l'État et le marché, ce texte revient sur la genèse de la LDN et met au jour ses ambigüités structurelles. Cette généalogie permet de relire les tentatives de réforme et les cadrages qui les ont fondés,depuis le Plan d'action foncier de 1996
Genetic and transcriptomic analysis of the <i>Bradyrhizobium</i> T3SS‐triggered nodulation in the legume <i>Aeschynomene evenia</i>
No full textThe data of the RNA-seq analysis are available at NCBI BioProject (accession: hite). The data supporting the findings of this study are available within the article and its Supporting Information (Figs S1–S3; Tables S1–S4; Dataset S1).International audience. Some Bradyrhizobium strains nodulate certain Aeschynomene species independently of Nod factors, but thanks to their type III secretion system (T3SS). While different T3 effectors triggering nodulation (ErnA and Sup3) have been identified, the plant signalling pathways they activate remain unknown.. Here, we explored the intraspecies variability in T3SS-triggered nodulation within Aeschynomene evenia and investigated transcriptomic responses that occur during this symbiosis. Furthermore, Bradyrhizobium strains having different effector sets were tested on A. evenia mutants altered in various symbiotic signalling genes.. We identified the A. evenia accession N21/PI 225551 as appropriate for deciphering the T3SS-dependent process. Comparative transcriptomic analysis of A. evenia N21 roots inoculated with ORS3257 strain and its ∆ernA mutant revealed genes differentially expressed, including some involved in plant defences and auxin signalling. In the other A. evenia accession N76, all tested strains nodulated the AeCRK mutant but not the AeNIN and AeNSP2 mutants, indicating a differential requirement of these genes for T3SS-dependent nodulation. Furthermore, the effects of AePOLLUX, AeCCaMK and AeCYCLOPS mutations differed between the strains. Notably, ORS86 nodulated these three mutant lines and required for this both ErnA and Sup3.. Taken together, these results shed light on how the T3SS-dependent nodulation process is achieved in legumes
Intercomparison of very high-resolution surface soil moisture products over Catalonia (Spain)
No full textInternational audienceThe surface soil moisture (SSM) is a key variable for monitoring hydrological, meteorological and agricultural processes. It can be estimated from active and passive microwave remote sensing data. While coarse-resolution SSM products (> 1 km) have already been evaluated for a large range of ecosystems, such assessments lack very high-spatial-resolution SSM products, although they are increasingly available thanks to very high-resolution radar data or disaggregation methods applied to coarse-scale products. Within this context, the aim of the current study is to carry out, for the first time, an intercomparison of high-spatial resolution SSM products using a large in situ SSM database collected from 33 fields located in the Ebro basin (Spain) that were cultivated with different crops and irrigated using different techniques. Three products are considered: (i) SSM Theia at the field scale derived from Sentinel-1 and Sentinel-2 data using a machine learning algorithm; ii) SSM ρ at 50-m resolution derived from the Sentinel-1 data using both the backscattering coefficient and the interferometric coherence based on the inversion of a simple radiative transfer model; and iii) SSM SMAP20m at 20-m resolution obtained by disaggregating SMAP SSM using Sentinel-3 and Sentinel-2 data. The statistical metrics computed on the whole database show that the two Sentinel-1 products outperform the disaggregated approach and that the SSM ρ product exhibits better statistical metrics than the SSM Theia product. This is mainly attributed to the inability of the SSM Theia approach to retrieve SSM >0.3 m 3 /m 3 . The correlation coefficients are >0.4 (up to 0.8) for 72%, 40% and 27% of the fields using SSM ρ , SSM Theia and SSM SMAP20m , respectively. Similarly, 80% of the fields had RMSE values between 0.06 m 3 /m 3 and 0.1 m 3 /m 3 using SSM ρ product against 36% using SSM Theia and 27% using SSM SMAP20m . In addition, the time series analysis showed that SSM SMAP20m was able to detect largescale wetting events such as rainfall that impacted the whole SMAP pixel while irrigation at the field scale was not detected, mainly because the very high-resolution Sentinel-2 data used for the disaggregation of Sentinel-3 land surface temperature were not related to the hydric status of the surface. The results show that while both Sentinel-1 products perform reasonably well for cereals and, to a lesser extent, for annuals, a drastic drop of the metrics is observed for tree crops. Finally, the spatial SSM pattern over the study area is also better depicted by the Sentinel-1 products than by the SSM SMAP20m by comparison to the airborne GLORI GNSS-R (Global Navigation Satellite System Reflectometry) SSM maps. This study highlights the limitations of SSM products over tree crops and provides insights for improving irrigation scheduling at the field scale
Beliefs and preferences as predictors of prophylactic adherence and lockdown compliance in South Africa
No full textInternational audienc
3D models related to the publication: An unexpected late paroxyclaenid (Mammalia, Cimolesta) out of Europe: dental evidence from the Oligocene of the Bugti Hills, Pakistan
No full textInternational audienceThis contribution contains the three-dimensional digital models of eleven isolated fossil teeth of a merialine paroxyclaenid (Welcommoides gurki), discovered from lower Oligocene deposits of the Bugti Hills (Balochistan, Pakistan). These fossils were described, figured and discussed in the following publication: Solé et al. (2024), An unexpected late paroxyclaenid (Mammalia, Pantolesta) out of Europe: dental evidence from the Oligocene of the Bugti Hills, Pakistan. Papers in Palaeontology. https://doi.org/10.1002/spp2.159
A Journey into Harold Hotelling's Economics
No full textInternational audienceHarold Hotelling (1895–1973) was a major contributor to twentieth-century American economics. The overall thrust of his research, and his view of the role of mathematics in the discipline, have so far received little attention. Based on an unprecedented examination of his work and professional archives, this article provides a thorough analysis of Hotelling's background and contribution to economics. A self-taught economist in the 1920s, Hotelling built a research program that, despite apparently being highly technical, was primarily conceived as applied science to solve concrete social and economic issues, from spatial competition to natural resource exhaustion and public utility regulation. Although Hotelling's research was not exempt from criticism, it remains profoundly inspiring for the twenty-first century, from both a theoretical and epistemological point of view. When we remember that he trained the greatest, from Kenneth J. Arrow to William Vickrey, his career and ideas are all the more worthy of consideration
LIPTAKOR, a participatory approach for increasing risk awareness and facilitating operational changes at artisanal gold mines
No full textInternational audienceThe literature highlights the importance of engaging local communities when attempting to raise awareness of environmental and human health-related risks at artisanal gold mines. There are, however, few reliable and tested methodologies available to achieve this or which can be adapted for use in a number of contexts. To help bridge this gap, we developed a tangible tool that takes the form of a game, which provides a space for participatory exploration of risk perceptions associated with artisanal gold mining. We present the results of this study, which was conducted in 2021 in the Nigerien Liptako–Gourma Region, and compare them to findings shared in the literature on risk perceptions related to artisanal gold mining