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Floch, J. - M., Marcon, E., & Puech, F. (2018). Les configurations de points. In V. Loonis, & M. - P. de Bellefon (Eds.), Manuel d'analyse spatiale (pp. 73–114). Insee-Eurostat.
Abstract: Les statisticiens peuvent être amenés à étudier précisément des données spatialisées, par exemple la distribution des revenus des ménages, l’implantation sectorielle d’établissements industriels ou commerciaux, la localisation des établissements scolaires au sein des villes, etc. Des réponses peuvent être apportées grâce à des analyses menées à une ou plusieurs échelles géographiques prédéfinies comme au niveau des quartiers, des arrondissements ou des îlots. Toutefois, il est tentant de vouloir préserver la richesse des données individuelles et travailler en conservant la position exacte des entités étudiées. Si tel est le cas, cela revient pour un statisticien à élaborer des analyses à partir de données géolocalisées sans procéder à une quelconque agrégation géographique. Les observations sont appréhendées comme des points dans l’espace et l’objectif est de caractériser ces distributions de points. Comprendre et maîtriser des méthodes statistiques qui traitent ces informations individuelles et
spatialisées permet de travailler sur des données qui sont aujourd’hui de plus en plus accessibles et recherchées car elles fournissent des analyses très précises sur les comportements des acteurs économiques (ELLISON et al. 2010 ; BARLET et al. 2013). Dans ce cadre d’analyse, plusieurs questions méthodologiques importantes se posent alors au statisticien qui dispose de jeux de points à analyser : comment représenter et caractériser spatialement de telles données en utilisant des milliers voire des millions d’observations ? Quels outils statistiques existent et peuvent être mobilisés pour étudier ces observations relatives aux ménages, salariés, firmes, magasins, équipements ou déplacements par exemple? Comment prendre en compte les caractéristiques qualitatives ou quantitatives des observations étudiées? Comment mettre en évidence des éventuelles attractions ou répulsions entre les points ou entre différents types de points? Comment peut-on évaluer la significativité des résultats obtenus? etc. Ce chapitre a pour but d’aider le statisticien à apporter des résultats statistiquement robustes à
partir de l’étude de données spatialisées qui ne reposent pas sur un zonage prédéfini. Pour ce faire, nous nous appuierons sur une revue de la littérature des méthodes statistiques qui permettent de caractériser des distributions de points et nous expliciterons les enjeux associés. Nous expliquerons à partir d’exemples simples les avantages et les inconvénients des approches les plus souvent retenues. Le code sous R fourni permettra de reproduire les exemples traités.
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Floch, J. - M., Marcon, E., & Puech, F. (2018). Spatial distribution of points. In V. Loonis, & M. - P. de Bellefon (Eds.), Handbook of Spatial Analysis (pp. 71–111). Insee-Eurostat.
Abstract: Statisticians carry out close examination of spatialized data, such as the distribution of household income, the location of industrial or commercial establishments, the distribution of schools in cities, etc. Answers can be found through analyses of one or more predefined geographical scales such as neighbourhoods, districts or statistical blocks. However, it is tempting to preserve the individual data and to work with the exact position of the entities that are being studied. If that is the case, statisticians have to conduct analyses based on geolocation data without carrying out any geographical aggregation. Observations are taken as points in space and the objective is to characterise these point distributions. Understanding and mastering statistical methods that process this individual and spatialized information enables us to work on data that are now increasingly accessible and sought after because they provide very precise analyses of distributions studied (Ellison et al. 2010; Barlet et al. 2013). In this framework of analysis, statisticians who have sets of points to analyse are faced with several important methodological questions: how can such data with thousands or even millions of observations be represented and characterised spatially? What statistical tools exist that can be used to study these observations relating to households, employees, firms, stores, equipment or travel, for example? How can the qualitative or quantitative characteristics of the observations being studied be taken into account? How can any attractions or repulsions between points or between different types of points be highlighted? How can we assess the significance of the results obtained, etc? The purpose of this chapter is to help statisticians to provide statistically robust results from the study of spatialized data that is not based on predefined zoning. To do this, we will review the literature on the subject of statistical methods used to characterise point distributions and we will explain the associated issues. We will use simple examples to explain the advantages and disadvantages of the most frequently adopted approaches. The code provided in R will be used to reproduce the examples covered.
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Fisher, G. L., Fu, T., Touboul, D., Della-Negra, S., Houël, E., Amusant, N., et al. (2017). Elucidation of natural product biosynthesis in Amazonian Sextonia rubra via 100 nm-scale TOF-SIMS tandem MS imaging. In 21st International Conference on Secondary Ion Mass Spectroscopy (SIMS21), Krakow (Poland), 10-15/09/2017 (1).
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Feuilly, H. (2008). Désenclavement de villages du Maroni : impacts sur le foncier agricole et forestier. Diploma thesis, AgroParisTech, Kourou - Guyane française.
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Faustin, M., Maciuk, A., Lebrini, M., Robert, F., Roos, C., & Figadere, B. (2012). Isolation of Geissospermum laeve alkaloids by pH-zone refining centrifugal partition chromatography for metal corrosion studies. In Planta Medica (Vol. 78, 1270).
Abstract: Control of metal corrosion is of technical, economical, environmental, and aesthetical importance. The use of corrosion inhibitors is one of the best options to protect metals and alloys from corrosion. The environmental toxicity of synthetic inhibitors has prompted the search for green compounds. Plant extracts have become important as an environmentally acceptable, readily available and renewable source for a wide range of biodegradable, heavy metals-free inhibitors. Among natural compounds, alkaloids have very high corrosion inhibition efficiency. An alkaloidic extract of Geissospermum laeve (Apocynaceae) has been fractionated by centrifugal partition chromatography using the pH-zone refining mode in order to investigate the effect of isolated alkaloids on C38 steel corrosion in HCl 1M. Indole alkaloids were identified by LC-MS, 1H and 13C NMR.
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Eva, H. D., de Miranda, E. E., Di Bella, C. M., Gond, V., Jones, S., Achard, F., et al. (2002). A vegetation map of South America. Environment series. Luxembourg: European Commission.
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Eparvier, V., Sorres, J., Rodrigues, A. M. S., Houël, E., Sorgenfrei, O., Ralli, M., et al. (2014). Bioprospection in French Guiana for the discovery of potential agrochemical and cosmetic agents. Planta Med, 80(10), Pd79.
Abstract: The present work is part of the Agrocos EUFP7 project and aimed at identifying new promising plant species exhibiting agrochemical properties or cosmetic interest. French Guiana being one of the megadiverse area of the globe considering plant biodiversity, 300 plant parts from 64 families were collected for the project. Among the 600 extracts evaluated as antifungals against phytopathogens, insecticides against plant pests and herbicides, 10% revealed an interesting activity. 7 of these extracts, mostly from the Leguminosae family, are currently under investigation for isolation and evaluation of pure compounds. Concerning cosmetic activity, 8 extracts from 5 different families were selected for further study. These results may lead to the development of novel products headed to agrochemical and cosmetic industry.
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El Khil, M., Houel, E., Eparvier, V., & Stien, D. (2012). Development of a statistical tool to predict anticandidal activity of essential oils. In Planta Medica (Vol. 78, 1065).
Abstract: There is a general agreement that natural volatile compounds of essentials oils from plants provide a great potential for discovery of new antimicrobial drugs such as anticandidal ones. In this work, 60 commercial essential oils were analysed by GC/MS and their inhibitory activity against the growth of three Candida strains was evaluated. We then conducted a chemometric analysis and proposed a tool to predict their capacity to inhibit the Candida sp. developpment. Raw data were pretreated and normalised using MZmine2.2 software. It was possible to identify some of the natural compounds with anticandidal properties using two statistical tools in XLstat7.5: hierarchical clustering analysis (HAC) and principal component analysis (PCA). We highlighted that essential oils containing limonene, 1,8-cineole, linalool and linalyl acetate were mostly inactive, whereas eugenol, thymol, carvacrol, geraniol, geranial and neral as major components of the oils seems to be linked to an interesting anticandidal activity. Linear regressions showed a high correlation between the concentration of these molecules and their antifungal activity. Exceptions to these general tendencies could be characteristic of synergistic or antagonistic interactions.
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Duvignau, M. (2011). Variation du signal olfactif lié à la pollination chez des plantes néotropicales : cas des aracées et des ficus en Guyane française. Sciences et Techniques du Languedoc. Master's thesis, Université Montpellier II, Montpellier.
Keywords: Ficus; Chalcidiens; Composes Organiques Volatils (Cov); Signature Chimique; Araceae; Cyclocephala; Odeur Florale
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Dumontet, V., Litaudon, M., Olivon, F., Poullain, C., Rasoanaivo, P., Stien, D., et al. (2012). Evaluation of natural products as potential agrochemical agents with insecticide, fungicide and herbicide activities. In Planta Medica (Vol. 78, 1226).
Abstract: The present work aims to identify new promising plant sources, which could be exploited for their agrochemical properties. A total of 484 natural products from academic libraries were selected for screening against four fungal pathogens, five insects and two plants. On the basis of the hits founded and a literature survey, the flora of source countries (New Caledonia, French Guiana, Madagascar, Panama, South Africa and Greece) was analysed for plants containing the desired scaffolds. Lists of 1800 plant part samples were thus established. The plant parts collected generated 3600 extracts that are being evaluated.
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