نتایج جستجو برای: northern africa

تعداد نتایج: 220275  

2015
Manuel Will Alex Mackay Natasha Phillips Michael D. Petraglia

Lithic technologies have been used to trace dispersals of early human populations within and beyond Africa. Convergence in lithic systems has the potential to confound such interpretations, implying connections between unrelated groups. Due to their reductive nature, stone artefacts are unusually prone to this chance appearance of similar forms in unrelated populations. Here we present data fro...

2006
Robin Derricourt

Palaeoanthropologists and archaeologists have advanced a wide range of explanatory narratives for the various movements of Homo erectus/Homo ergaster, and the first modern Homo sapiens, “Out of Africa”—or even back again. The application of Occam’s razor—a parsimonious approach to causes—gives a more cautious approach. There is nothing in the available evidence that would require the ability fo...

2011
J. H. Giliomee

Any new alien insect that succeeds in reaching and establishing in South Africa is a cause for concern, especially if it is phytophagous and feeds on commercially important plants. It is important that this should be detected early and documented so that the status of the insect as a pest can be assessed. Where necessary, the agricultural sector, trading partners and neighbouring countries shou...

2004
G. S. Jenkins

The potential enhancement of tropospheric column ozone values over the Tropical Atlantic Ocean on a seasonal basis by lightning is investigated using satellite derived ozone data, TRMM lightning data, ozonesonde data and NCEP reanalysis during 1998–2001. Our results show that the number of lightning flashes in Africa and South America reach a maximum during September, October and November (SON)...

Journal: :Journal of the South African Veterinary Association 2013
Mary-Louise Penrith

The histories of the two swine fevers in southern Africa differ widely. Classical swine fever (hog cholera) has been known in the northern hemisphere since 1830 and it is probable that early cases of 'swine fever' in European settlers' pigs in southern Africa were accepted to be that disease. It was only in 1921 that the first description of African swine fever as an entity different from class...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Hugo Reyes-Centeno Silvia Ghirotto Florent Détroit Dominique Grimaud-Hervé Guido Barbujani Katerina Harvati

Despite broad consensus on Africa as the main place of origin for anatomically modern humans, their dispersal pattern out of the continent continues to be intensely debated. In extant human populations, the observation of decreasing genetic and phenotypic diversity at increasing distances from sub-Saharan Africa has been interpreted as evidence for a single dispersal, accompanied by a series of...

2010
Wentao Shi Qasim Ayub Mark Vermeulen Rong-guang Shao Sofia Zuniga Kristiaan van der Gaag Peter de Knijff Manfred Kayser Yali Xue Chris Tyler-Smith

We have investigated human male demographic history using 590 males from 51 populations in the Human Genome Diversity Project - Centre d'Etude du Polymorphisme Humain worldwide panel, typed with 37 Y-chromosomal Single Nucleotide Polymorphisms and 65 Y-chromosomal Short Tandem Repeats and analyzed with the program Bayesian Analysis of Trees With Internal Node Generation. The general patterns we...

2014
Jean-Renaud Boisserie Antoine Souron Hassane Taïsso Mackaye Andossa Likius Patrick Vignaud Michel Brunet

During the latest Miocene and the early Pliocene, tetraconodontine suids were the most predominant large omnivorous mammals in Africa. Yet, new species were often identified on the grounds of limited evidence, a situation impacting their value for biochronological correlations as well as for environmental and biogeographical reconstructions. The description of the most abundant known collection...

2017
Seohyun Lee Yoon-min Cho Sun-Young Kim

BACKGROUND Mobile health (mHealth), a term used for healthcare delivery via mobile devices, has gained attention as an innovative technology for better access to healthcare and support for performance of health workers in the global health context. Despite large expansion of mHealth across sub-Saharan Africa, regional collaboration for scale-up has not made progress since last decade. METHODS...

2004
Drew T. Shindell Gavin A. Schmidt Michael E. Mann G. Faluvegi

[1] We have analyzed the mean climate response pattern following large tropical volcanic eruptions back to the beginning of the 17th century using a combination of proxybased reconstructions and modern instrumental records of cold-season surface air temperature. Warm anomalies occur throughout northern Eurasia, while cool anomalies cover northern Africa and the Middle East, extending all the wa...

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