Algiers, Algeria

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Ababsa S.,University of Oum El Bouaghi | Ababsa S.,University of Mentouri Constantine | Djamai F.,University of Algiers 2 | Zouchoune B.,University of Oum El Bouaghi | Zouchoune B.,University of Mentouri Constantine
Journal of Cluster Science | Year: 2014

Density functional theory (DFT) method with B3LYP functional and 6-311++G(d,p) basis set has been used to predict the geometries, relative stabilities, electronic structures and bonding analysis of Mixed AlmBn−mHn 2− and CmBn−mHn 2−m (n = 6, 10, 12 and m = 1, 2) clusters; being compared to the BnHn 2− ones. Therefore, the DFT results suggest that the replacing of boron by aluminium or carbon is governed by Natural net charges following Gimar’s and Williams’s rules. The AlmBn−mHn 2− structures are relatively distorted compared to those of BnHn 2− and CmBn−mHn 2−m. In AlmBn−mHn 2− structures Al atoms prefer the adjacent sites, however for the C2Bn−2Hn cluster cages, the carbon atoms are positioned at diametrically opposed sites. The large HOMO–LUMO gaps show that the predicted clusters have chemical stabilities, principally, those of AlmBn−mHn 2− ones, which are not experimentally isolated. The optimized geometries obtained through boron substitution by Al and C lead to compactness and to contracted structures, respectively, where B–B bonds are the shortest in mono- and di-carbaboranes. © 2014, Springer Science+Business Media New York.


Pares J.M.,Research Center for Human Evolution | Sahnouni M.,Research Center for Human Evolution | Sahnouni M.,Indiana University Bloomington | Sahnouni M.,Center National Of Recherches Prehistoriques | And 5 more authors.
Quaternary Science Reviews | Year: 2014

The question of the earliest hominid settlements in northern Africa has been under debate for a number of years due to the lack of precise chronologies. Here we present new paleomagnetic data that supports an Olduvai Subchron age for the archaeological sites at Ain Hanech and El-Kherba, in northern Algeria. Our study is based on a 22m-thick magnetostratigraphy of the Ain Hanech Formation, which includes contextualized Oldowan and Acheulian lithic tools. Characteristic remanent magnetization directions were obtained from both thermal and alternating field demagnetization procedures of specimens from twenty five sampled horizons. Our results reveal the presence of the Olduvai Subchron in the upper part of the stratigraphic section, constraining the age of these important archaeological sites in northern Africa. © 2014 Elsevier Ltd.


Sahnouni M.,National Center for Research on Human Evolution | Sahnouni M.,Center National Of Recherches Prehistoriques | Sahnouni M.,Indiana University Bloomington | Rosell J.,Rovira i Virgili University | And 10 more authors.
Journal of Human Evolution | Year: 2013

The current archaeological data on early hominin subsistence activities in Africa are derived chiefly from Sub-Saharan Plio-Pleistocene sites. The recent studies at El-Kherba (Ain Hanech) in northeastern Algeria expand the geographic range of evidence of hominin subsistence patterns to include the earliest known archaeological sites documented in North Africa. Dated to 1.78 million years ago (Ma), excavations from El-Kherba yielded an Oldowan industry associated with a savanna-like fauna contained in floodplain deposits. The faunal assemblage is dominated by large and medium-sized animals (mainly adults), especially equids, which are represented by at least 11 individuals. The mammalian archaeofauna preserves numerous cut-marked and hammerstone-percussed bones. Made of primarily limestone and flint, the stone assemblage consists of core forms, débitage, and retouched pieces. Evidence of usewear traces is found on several of the flint artifacts, indicating meat processing by early hominins. Overall, our subsistence analysis indicates that early hominins were largely responsible for bone modification at the site, which is also corroborated by other relevant taphonomic evidence. Moreover, at 1.78 Ma, the cutmarked bones recovered from El-Kherba represent the earliest known evidence for ancestral hominin butchery activities and large animal foraging capabilities in northern Africa. © 2012 Elsevier Ltd.


Boudrifa H.,University of Algiers 2 | Amiar A.,University of Algiers 2
Occupational Safety and Hygiene II - Selected Extended and Revised Contributions from the International Symposium Occupational Safety and Hygiene, SHO 2014 | Year: 2014

The aim of this study is to assess the attitude of the health staff towards washing hands and how much they are prepared to obey to the rules as well as to find out factors that affect this type of preventive behaviour, which can be a threat to their health as well to the patients' health. The analysis of the results showed that the individuals of the study sample are not fully aware of the different cases that need washing hands before or after these cases. They were not fully aware of the different techniques and conditions for washing hands, nor do they conform to them. The results also indicated that there was a lack in providing the necessary tools and material for washing hands. It is therefore concluded that continuous campaigns for raising awareness of washing hands should be introduced as an absolute necessity. © 2014 Taylor & Francis Group, London, UK.


University of Algiers 2 | Entity website

2015


University of Algiers 2 | Entity website


University of Algiers 2 | Entity website

2015


University of Algiers 2 | Entity website

2015


University of Algiers 2 | Entity website

2015


University of Algiers 2 | Entity website

2015

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