Le goupi (Goupia glabra Aubl), essence forestière d'avenir en Guyane : analyse bibliographique

International audienc

La géopolitique : une histoire contrastée

Rivalités de pouvoirs ou d’influences sur des territoires, rivalités pour le contrôle ou la domination de territoires de grande ou de très petite taille, rivalités entre des pouvoirs politiques de toutes sortes, et pas seulement entre des États, mais aussi entre des tribus, des mouvements politiques ou religieux... tel est le sens qu’Yves Lacoste donne au mot géopolitique.According to Yves Lacoste, the word geopolitics means: power rivalries within territories; competition for the control or the domination of large or very small territories of all sorts. These rivalries occur not only between nation States but also between tribes, political groups or religious forces

L’écosystème buccal chez le patient âgé

La bouche est une cavité naturelle complexe qui forme le segment initial du tube digestif. Elle est un acteur essentiel des fonctions vitales que sont la nutrition, le langage et la communication. L’ensemble de la bouche (dents, parodonte, muqueuses, langue) est constamment hydraté et lubrifié par la salive. À tout âge, un équilibre s’établit entre la prolifération bactérienne, le flux salivaire et la réponse tissulaire : c’est l’écosystème buccal. La régulation de cet écosystème participe à la protection du complexe buccal contre les pathologies inflammatoires et infectieuses courantes (caries, gingivites, parodontopathies,candidoses). Chez les patients âgés, la modification du flux salivaire, l’apparition de pathologies spécifiques (caries radiculaires, absence de dents, parodontopathies. . .), les conditions locales (présence de prothèses amovibles), le développement de pathologies générales telles que le diabète, l’hypertension, la baisse des défenses immunitaires, la négligence de l’hygiène quotidienne sont autant d’éléments qui vont déséquilibrer l’écosystème buccal, favoriser la formation du biofilm (plaque bactérienne) et fragiliser les tissus bucco-dentaires. Le maintien de cet écosystème est essentiel pour le patient âgé : il lui permet de s’alimenter dans de bonnes conditions et ainsi prévenir les risques de dénutrition. Les auteurs décrivent la physiopathologie buccale (flore buccale, sécrétion salivaire) et les stratégies à adopter pour préserver l’équilibre buccal chez le patient âgé

Government Geoscience Stimulates Mineral Exploration in the Superior Province, Northern Québec

This paper summarizes new geologic information, and highlights exploration opportunities in the northeastern part of the Superior Province since 1997, as a result of the Far North Program undertaken by Géologie Québec. The first phase of the program was a regional lake-sediment geochemical survey, where 26,000 samples were collected north of 55°N from an area of approximately 350,000 km2. The resulting database attracted many mining companies to the region and led to numerous mineral discoveries. The second phase, started in 1998, consisted of extensive geological mapping, supplemented by U-Pb geochronological work; by 2003, more than twenty, 1:250,000 mapping projects were completed. The Far North Program is now in its final phase and it will produce a comprehensive geological and metallogenic synthesis of the new data from the areas surveyed. About forty previously unknown volcano-sedimentary belts, numerous mafic-ultramafic intrusions and sixteen different mineral deposit types have been identified. Since 1997, this has resulted in a surge of exploration activity that has seen more than $38 million in expenditures by private industry. SOMMAIRE Le présent article présente un résumé des nouvelles informations géologiques disponibles et décrit des cibles d'exploration mises au jour depuis 1997 dans le nord-est de la Province du lac Supérieur et qui découlent du programme d'exploration du Grand Nord de Géologie Québec. La première étape de ce programme a consisté en un échantillonnage géochimique régional de sédiments lacustres, où 26 000 échantillons ont été prélevés au nord du 55e parallèle, sur une superficie de près de 350 000 km2. La base de données ainsi constituée a attiré de nombreuses sociétés minières dans la région et de nombreuses découvertes minérales ont été faites. Amorcée en 1998, la deuxième étape a consisté en une cartographie géologique systématique, appuyée par des datations géochronologiques U-Pb. Et, en 2003, plus de 20 cartes à l'échelle 1:250 000 avaient été complétées. Le programme du Grand Nord en est maintenant à sa dernière étape, laquelle aboutira à la production d'une synthèse géologique et métallogénique à partir des nouvelles données provenant des régions étudiées. Environ une quarantaine de bandes volcano-sédimentaires, de nombreuses intrusions mafiques et ultramatiques, et seize types de gisements minéralogiques différents y ont été décrits. Depuis 1997, ce programme a entraîné des investissements d'exploration par l'entreprise privée dépassant les 38 M$

Landscape design for soil conservation under land use and climate change

International audienceSoils and landscapes evolve simultaneously. Soil evolution is controlled by redistribution and transformation processes influenced by topographic and climatic parameters, with also a major contribution of management strategies. The perennial landscape features have a strong influence on soil spatial distribution (geometry) and soil genesis. Building landscapes which enhance soil resilience to degradation processes and increase soil services appears as a promising way to adapt to forthcoming climatic and land use evolutions. The presentation aims to synthetize major results from a research program nicknamed Landsoil which focused on the evolution of agricultural soils over medium time scales (decades to centuries) in relation to changing conditions of land use and climate. Precise study of the soil 3D organization in three contrasted landscapes (Brittany, Touraine, Languedoc-Roussillon) enabled to link soil redistribution in space to landscape components (field geometry, hedges or ditches network) and their past evolution. A dynamic and high resolution spatial modeling approach was developed coupling erosion processes and soil organic matter evolution and was calibrated over past evolution using dating techniques (Cs137, C14, OSL). The resulting Landsoil model was afterwards applied in a prospective manner under different scenarios of land use and climate change over the 21th century. Indicators of soil vulnerability and soil resilience were defined and tested by the comparison of several prospective scenarios applied on a same landscape and by comparison of the contrasted landscapes

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Le concept de sous-développement et la Géographie

The concept of under-development in geography The concept of under-development in geography (Abstract). — The concept of underdevelopment often causes geographers to be réticent, and is also the object of confiicting opinions. By using strictly geogra-phical criteria it is possible to give an objective définition : — Underdevelopment is an internai imbalance between the growth of the population and the insufflciency of the increase in the resources which the population has at its-disposai. This insufficient économie growth is the resuit of a failure to utilise the natural potential to the full. This négative balance-sheet between peoples an& natural resources suberibes completely to the theory of « Possibilisme » of Vidal de La Blache. Obviously this theory does not exclude geographical determinism the rôle of which appears ail the greater when the facts are studied on a greater scale (local and régional circumstances). The study of underdevelopment accor-ding to régional geographical methods obviously remains essential. But it also seems more and more necessary to carry out comparative studies between the various parts of the underdeveloped areas and to examine the circumstances of underdevelopment in its world context. This cornes within the methods of gênerai geography which can be very usefully transformed by the adoption of the concept of underdevelopment as a fundamental geographical notion.Lacoste Yves. Le concept de sous-développement et la Géographie. In: Annales de Géographie, t. 76, n°418, 1967. pp. 644-670

Le sous-développement : quelques ouvrages significatifs parus depuis dix ans

Lacoste Yves. Le sous-développement : quelques ouvrages significatifs parus depuis dix ans. In: Annales de Géographie, t. 71, n°385, 1962. pp. 247-278