Search results for "Central Africa"
showing 10 items of 22 documents
Perspectives on Sustainable Development in the Context of Public Health Issues
2015
Abstract Health is an integral part of sustainable development, a process that can’t be materialized if there is a high prevalence of diseases, a high percentage of those is due to environmental factors. An important component of health is the healthy nutrition, especially of children and pregnant women. Iodine is an essential micronutrient for a good nutrition that covers the physiological needs of the body, iodine deficiency having important consequences for mother and fetus, then for children, especially in the first years of life. The main role of iodine in the body is due to his importance for synthesis of thyroid hormones involved in growth and development of psychic and somatic body,…
Paléoenvironnements et caractérisation des roches mères pétrolières des séries pré-salifères du bassin intérieur du Gabon
2003
Resume Le bassin interieur du Gabon, dont l'histoire est liee a la separation des continents Sud-Americain et Africain, comprend des depots continentaux fluvio-lacustres, localement glaciaires, dates du Precambrien superieur a l'Aptien p.p., surmontes par des facies marins aptiens et albiens. L'analyse par pyrolyse Rock–Eval d'echantillons d'affleurements et de forages preleves dans ce bassin met en evidence la presence de facies siliciclastiques riches en matiere organique (jusqu'a 25 % de carbone organique total) de types I et II. Ces niveaux, qui se rencontrent dans le Permien, le Neocomien-Barremien ainsi que dans l'Aptien, constituent d'excellentes roches meres et sont a l'origine des …
Rainfall variability in subequatorial America and Africa and relationships with the main sea-surface temperature modes (1951–1990)
1995
The rainfall variability of subequatorial South America and Africa is poorly documented owing to the scarcity of data. We present a new land-only data set of monthly precipitation from 1951 to 1990, focusing on subequatorial South America and Africa, which improves the knowledge of rainfall variability and allows comparisons with GCM outputs. The results of multivariate analyses are compared with those performed on the best actual global rainfall data set developed by Mike Hulme. The main modes of bimonthly rainfall variability are not located in the major rain-forest basins of Za'ke and Amazonia, but rather on the tropical margins, such as Venezuela or Sudan, and near-coastal equatorial ar…
État actuel des réseaux de mesures éco-climatiques en Afrique centrale : les ambitions du projet de recherche international FORGREENE.
2016
This work presents an overview of spatio-temporal quality andspatial density of rainfall networks of Cameroon, Gabon, Congo, CAP and DRC, particularly in the recentperiod (1973-2014) through the GSOD international database. Faced with enormous gaps observed, theseresults will help to select metrological and analytical orientations in FORGREENE project (Tropical forestsgreeness and cloudiness in Central Africa: present conditions and future evolution). A comparison with rainfallsatellite estimates (RFE type) also indicates their great potential, provided they are based on in situ validations.
Evolution of dry season low cloud cover over the Atlantic coast of Central Africa from diurnal to interannual scale
2022
Despite its bioclimatic importance, few studies have focused on the stratiform low-level cloud cover ofthe dry season (June-September) of the Atlantic coast of Central Africa. Using in-situ data documenting theperiod 1971-2019, we show that this cloud cover is underestimated by SAFNWC satellite observations andCMIP6 models. We identify three types of days: clear, cloudy at night and totally cloudy, the latterbeing more frequent on the coast and inland, to the windward of the Cristal and Chaillu Mountains. Onan interannual scale, temperature anomalies in the South Tropical Atlantic, the equatorial Pacific and theCongo Basin, by modulating the meridional and zonal circulation cells, influence…
Analysis of cloudiness and solar radiation diurnal cycles for a better understanding of the forests greenness mean annual cycle in Central Africa.
2016
To better understand the Central Africa forests sensitivity toclimate variability, we jointly analyse the mean annual cycles of greenness, rainfall, cloudiness and solarradiation for the target region 0-5°N/12-19°E using high resolution satellite data. Our results demonstrate theimportance of the diurnal scale for understanding the mean annual cycles of rainfall, cloudiness and solarradiation and the way they shape those of forest greenness. They also suggest that whereas the March-Mayrainy season appears optimal for greenness especially because of favorable light conditions, water availabilityis the main controlling factor in December-January the main dry season and in February at the star…
Cycles diurnes de rayonnement solaire et forets en Afrique Centrale.
2018
The sunlightconditions prevailing in Central Africa, and their potential impact on forests traits and functioning, have neverbeen fully explored. Using satellite estimates documenting mostly the period 2005-2013, and accounting forscale interactions between the diurnal and annual cycles, we demonstrate that the seasonality of sunlight levelsstrongly vary across Central Africa forests. Gabon stands out with a main dry season strongly light-deficient,cool and moist. An original map of terra firme forest types developed by CIRAD shows that most of theevergreen forests of Central Africa develop in Gabon. We postulate that despite a mean annual precipitationamount below 2000 mm/yr, the Gabonese …
A new Lagomorph from the late Miocene of Chad (central Africa)
2007
A new species of the genus Serengetilagus, here named S. tchadensis n. sp., is described from Toros Menalla deposits, Late Miocene of Djurab Erg (North Chad, central Africa). It shows primitive features, such as a simple archaeolagine-type p3, with only two main external folds, and upper cheek teeth strongly widened with wear. Its size and skeletal features resemble S. praecapensis from the Middle Pliocene of Laetoli (Tanzania). They differ in several cranial and dental features (choanae width, zygoma, orbits, basicranial-basifacial angle, lack of hypoflexus in P2, short and asymmetric hypoflexus in P3-M2, lack of lingual folds in p3, etc). Individual variations in S. tchadensis n. sp. appr…
<strong><em>Chilocoris laevicollis</em> Horváth, 1919, and<em> Ch. umbricola</em> Linnavuori, 1993—two trogloxenic burr…
2016
First country records of two burrower bugs, Chilocoris laevicollis , and Ch . umbricola (Hemiptera: Heteroptera: Cydnidae) from Gabon (Central Africa) are presented. The study was based on the specimens collected by Dr. V. Aellen, a well-known Swiss speleologist, taken from two caves near Lastoursville in the Gabonese Republic. Diagnostic characters for both recorded species are provided, and data on their biology and distribution are summarized.