Tunis University

About: Tunis University is a education organization based out in Tunis, Tunisia. It is known for research contribution in the topics: Population & Thin film. The organization has 11745 authors who have published 15400 publications receiving 154900 citations. The organization is also known as: University of Tunis & UT.

Application of multivariate statistical analysis and hydrochemical and isotopic investigations for evaluation of groundwater quality and its suitability for drinking and agriculture purposes: case of Oum Ali-Thelepte aquifer, central Tunisia.

Abstract: Groundwater plays a dominant role in arid regions; it is among the most available water resources in Tunisia. Located in northwestern Tunisia, Oum Ali-Thelepte is a deep Miocene sedimentary aquifer, where groundwater is the most important source of water supply. The aim of the study is to investigate the hydrochemical processes leading to mineralization and to assess water quality with respect to agriculture and drinking for a better management of groundwater resources. To achieve such objectives, water analysis was carried out on 16 groundwater samples collected during January-February 2014. Stable isotopes and 26 hydrochemical parameters were examined. The interpretation of these analytical data showed that the concentrations of major and trace elements were within the permissible level for human use. The distribution of mineral processes in this aquifer was identified using conventional classification techniques, suggesting that the water facies gradually changes from Ca-HCO3 to Mg-SO4 type and are controlled by water-rock interaction. These results were endorsed using multivariate statistical methods such as principal component analysis and cluster analysis. The sustainability of groundwater for drinking and irrigation was assessed based on the water quality index (WQI) and on Wilcox and Richards's diagrams. This aquifer has been classified as "excellent water" serving good irrigation in the area. As for the stable isotope, the measurements showed that groundwater samples lay between global meteoric water line (GMWL) and LMWL; hence, this arrangement signifies that the recharge of the Oum Ali-Thelepte aquifer is ensured by rainwater infiltration through mountains in the border of the aquifer without evaporation effects.

IncI1 plasmids carrying bla(CTX-M-1) or bla(CMY-2) genes in Escherichia coli from healthy humans and animals in Tunisia.

Abstract: The objective was to determine the location of blaCTX-M-1 and blaCMY-2 genes in 33 Escherichia coli isolates previously obtained from healthy humans, pets, and food-producing animals in Tunisia, and to characterize the genetic lineages of isolates. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE)-XbaI and multilocus sequence typing (MLST). Plasmids were analyzed by S1-PFGE, polymerase chain reaction-based replicon typing, and plasmid MLST. Conjugation experiments were performed. The blaCTX-M-1 and blaCMY-2 genes were studied by I-Ceu1-PFGE and S1-PFGE, and subsequent hybridization with specific probes. Eighteen different sequence types (STs) were identified among the 30 CTX-M-1-producing isolates, 5 of them being detected in 17 isolates (ST/phylogroup): ST57/D, ST155/B1, ST58/B1, ST10/A, and ST398/A. Most of the blaCTX-M-1-positive isolates had different PFGE profiles, with the exception of four human and pet isolates of lineage ST57 with related PFGE profiles (>80% identity). Thr...

Morphological and Phylogenetic Studies of Marine Myxobolus spp. from Mullet in Ichkeul Lake, Tunisia

Abstract: Six species of the genus Myxobolus (Myxozoa) from the marine environment were collected from two species of mullet (Mugil cephalus and Liza ramada) in Ichkeul Lake, Tunisia. Four of these species were described previously (Myxobolus bizerti, Myxobolus ichkeulensis, Myxobolus spinacurvatura, and Myxobolus episquamalis) and two (Myxobolus exiguus and Myxobolus muelleri) are redescribed. The small subunit ribosomal (18S rDNA) sequences of these six myxozoans were obtained and compared to traditional criteria used in the identification and taxonomy of myxozoan species (such as spore morphology, host specificity, and tissue tropism). A distance analysis of 1,600-1,700 base pairs of the 18S rDNA of the six species indicates that they formed a monophyletic group separate from Myxobolus spp. found as parasites of freshwater fish. The sequence analyses also confirm that these morphologically different Myxobolus spp. that infect mullet represent different species. Lastly, M. exiguus and M. muelleri, which were found in the same host, exhibit clear differences in spore morphology but sequencing of two different regions of the 18S rDNA show they are closely related. These results demonstrate the utility of DNA sequence data in providing more detailed relationships among the Myxobolus species based upon existing morphological taxonomic approaches. We suggest that future descriptions of Myxobolus spp. provide both careful spore descriptions as part of the traditional criteria but also 18S rDNA sequence data that will aid in situations where morphological details may be absent or misleading.

What can we learn about Islamic banks efficiency under the subprime crisis? Evidence from GCC Region

Abstract: The study investigates the influence of subprime crisis on the efficiency of Islamic banks in the GCC region using data envelopment analysis for the period spanning from 2005 to 2011. We focus on three aspects of efficiency, namely overall technical efficiency, pure technical efficiency and scale efficiency. Empirical findings highlight a slight decline in Islamic bank efficiency further to the subprime crisis just like their conventional peers all over the world. However, most Islamic banks have remained efficient whereas some of them witnessed a relatively minor decrease in their efficiency level. The most acute intensity of drop in efficiency was recorded on average in 2009 for all categories of efficiency; that is two years after the subprime crisis occurrence.