Search results for " africa"

Trends of mean temperatures and warm extremes in northern tropical Africa (1961-2014) from observed and PPCA-reconstructed time series

2016

Trends in daily maximum (TX) and minimum (TN) temperatures and indices of warm extremes are studied in tropical North Africa, west of the eastern African highlands, from 1961 to 2014. The analysis is based on the concatenation and cross-checking of two observed databases. Due to the large number of missing entries (~25%), a statistical infilling using probabilistic principal component analysis was applied. Averaged over 90 stations, the linear trends of annual mean TX and TN equal respectively +0.021 °C/yr and +0.028 °C/yr. The frequency of very hot days (TX > 35°C) and tropical nights (TN > 20°C), as well as the frequency of daily TX and TN above the 90th percentile (p90) (“warm days” and …

Performance of DEMETER calibration for rainfall forecasting purposes: Application to the July–August Sahelian rainfall

2008

International audience; This work assesses and compares the skill of direct and model-output-statistics (MOS) calibrated hindcasts of the July–August rainfall amounts for the dry period 1980–2000 over the Sahel issued from the Development of a European Multimodel Ensemble System for Seasonal to Interannual Prediction (DEMETER) experiment, with the aim to highlight among the simulated parameters, i.e., those potentially relevant for rainfall forecasts purposes. Three approaches were used: the DEMETER (1) direct rainfall, (2) MOS-calibrated rainfall, and (3) MOS-calibrated atmospheric dynamics and energy. Canonical correlation analyses (CCA) were employed in the two latter approaches to calib…

Spatial coherence and potential predictability assessment of intraseasonal statistics of wet and dry spells over Equatorial Eastern Africa

2012

The aim of this study was to derive components of the intraseasonal rainfall variations from the daily rainfall in the Equatorial Eastern Africa region and assess their spatial coherence, a pointer to their potential predictability. Daily rainfall observations from 36 stations distributed over Equatorial Eastern Africa and extending from 1962 to 2000 were used. The March to May and October to December periods commonly referred to as the long and short rainfall seasons respectively were considered. Seasonal and intraseasonal statistics at the local (station) level were first defined. The stations were also grouped into near-homogeneous (sub-regional) zones based on daily rainfall. Similarly,…

Monthly survival of African Sylvia warblers in a seasonally arid tropical environment

2006

Latitudinal gradients of life-history traits in animals are thought to be shaped by environmental variables. For example, it has been suggested that the increase in avian clutch size from the tropics towards the northern temperate regions is caused by a reduced survival of adult birds in the north due to increasing environmental seasonality. However, the tropical savannahs of East Africa show pronounced seasonality in resources caused by distinct rainy and dry seasons. This raises the question of whether survival and other life-history traits of birds living in these tropical savannahs are influenced by this seasonality, making them more similar to northern temperate species. We used 2-year…

La Place de l'Etat en Afrique selon la Banque mondiale : De l'ajustement structurel à l'ajustement social. Les limites d'une politique néo-libérale «…

2007

07003 - 17 p.; Les Documents de travail de l'IREDU 2007/3; Cette contribution a pour objectif d'analyser le changement de discours que porte la Banque mondiale sur la réforme de l'État en Afrique, et ce dans la sphère éducative. Après examen, il ressort que malgré les nouveaux discours de « lutte contre la pauvreté », la politique néo-libérale de la Banque mondiale accorde à l'État une place toujours aussi mineure dans la conception et l'exécution des politiques éducatives. On aurait pu croire à la réalité d'une évolution de la politique d'ajustement structurel stricte vers une politique d'ajustement social où des acquis fondamentaux seraient pris en compte concernant le domaine social. Il …

Chemical composition of modern and fossil hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation – Part 2: A…

2012

Abstract. For reconstructing environmental change in terrestrial realms the geochemistry of fossil bioapatite in bones and teeth is among the most promising applications. This study demonstrates that alkaline earth elements in enamel of Hippopotamids, in particular Ba and Sr are tracers for water provenance and hydrochemistry. The studied specimens are molar teeth from Hippopotamids found in modern and fossil lacustrine settings of the Western Branch of the East African Rift system (Lake Kikorongo, Lake Albert, and Lake Malawi) and from modern fluvial environments of the Nile River. Concentrations in enamel vary by ca. two orders of magnitude for Ba (120–9336 μg g−1) as well as for Sr (9–21…

Il primo cristianesimo nell'Africa Romana e in Sicilia. Quattro note

2011

Bibliometric analysis of publications by South African viticulture and oenology research centres

2012

We analysed the production, impact factor of, and scientific collaboration involved in viticulture and oenology articles associated with South African research centres published in international journals during the period 1990–2009. The articles under scrutiny were obtained from the Science Citation Index database, accessed via the Web of Knowledge platform. The search strategy employed specific viticulture and oenology terms and was restricted to the field ‘topic’. The results showed that 406 articles were published during the review period, with the most number of publications being in the South African Journal of Enology and Viticulture (n = 34), American Journal of Enology and Vit…

Prefazione a Sulaiman Addonia, Il silenzio è la mia lingua madre

2022

Sulaiman Addonia's 2018 novel Silence is My Mother Tongue, uncharacteristically set in a refugee camp, follows the sentimental education of a girl, Saba, in the place that she, her brother, and their friends have learnt to call home. The Preface to the Italian edition remarks how this classic and yet extraordinary coming-of-age novel offers a fundamental counter-narrative to the mainstream representations of life stories of minor refugees all over the world.

On the distribution and subspecific variation of the Tunisian- Algerian endemicDelphinium sylvaticum(Ranunculaceae)

2015

The morphology and biogeography of the Tunisian–Algerian endemic Delphinium sylvaticum Pomel has been studied in Tunisia. As presented here, this study resulted in an enlargement of the known distribution and in the description of two new subspecies: D. sylvaticum subsp. ichkeulianum El Mokni, Domina, Sebei & El Aouni and D. sylvaticum subsp. purpureum El Mokni, Domina, Sebei & El Aouni native to Tunisia in Mogods and in the northeast regions, respectively. Besides ecological features and clearly separated distribution, the two new subspecies show very well differentiated morphology. An updated distribution map and a diagnostic key of the studied taxa are provided.