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.

The use of discretionary loan loss provisions by Islamic banks and conventional banks in the Middle East region

Abstract: Purpose – The purpose of this paper is to study earnings management practices of Islamic banks and conventional banks in the Middle East region. First, the authors examine factors that may influence Islamic banks managers' use of discretion in reporting loan loss provisions (LLP). Second, the authors investigate differences that may exist between Islamic banks and non-Islamic banks in terms of discretionary loan loss provisions (DLLP) used to manipulate accounting earnings. Design/methodology/approach – This empirical study uses an unbalanced panel data of 21 Islamic banks, 18 conventional banks with Islamic windows and 33 conventional banks, from seven Middle East countries during a period that ranges from 2000 to 2008. The authors use a two-stage approach in order to examine factors that may influence the use of discretion by Islamic banks' managers. Findings – The empirical results reveal that Islamic banks use DLLP for both earnings and capital management. External financing is also found to be a dete...

Double logarithmic inequality with a sharp constant

Abstract: We prove a Log Log inequality with a sharp constant. We also show that the constant in the Log estimate is "almost" sharp. These estimates are applied to prove a Moser-Trudinger type inequality for solutions of a 2D wave equation.

Cross-section and rate coefficient calculation for electron impact excitation, ionisation and dissociation of H 2 and OH molecules

Abstract: The weighted total cross-section (WTCS) theory is used to calculate electron impact excitation, ionisation and dissociation cross-sections and rate coefficients of OH, H2, OH+, H2 +, OH- and H2 - diatomic molecules in the temperature range 1500–15000 K. Calculations are performed for H2(X, B, C), OH(X, A, B), H2 +(X), OH+(X, a, A, b, c), H2 -(X) and OH-(X) electronic states for which Dunham coefficients are available. Rate coefficients are calculated from WTCS assuming Maxwellian energy distribution functions for electrons and heavy particles. One and two temperature (θe and θg respectively for electron and heavy particles kinetic temperatures) results are presented and fitting parameters (a, b and c) are given for each reaction rate coefficient: k(θ) = a (θb)exp (-c/θ).

Pseudomonas rhizophila S211, a New Plant Growth-Promoting Rhizobacterium with Potential in Pesticide-Bioremediation.

Abstract: A number of Pseudomonas strains function as inoculants for biocontrol, biofertilization, and phytostimulation, avoiding the use of pesticides and chemical fertilizers. Here, we present a new metabolically versatile plant growth-promoting rhizobacterium, Pseudomonas rhizophila S211, isolated from a pesticide contaminated artichoke field that shows biofertilization, biocontrol and bioremediation potentialities. The S211 genome was sequenced, annotated and key genomic elements related to plant growth promotion and biosurfactant (BS) synthesis were elucidated. S211 genome comprises 5,948,515 bp with 60.4% G+C content, 5306 coding genes and 215 RNA genes. The genome sequence analysis confirmed the presence of genes involved in plant-growth promoting and remediation activities such as the synthesis of ACC deaminase, putative dioxygenases, auxin, pyroverdin, exopolysaccharide levan and rhamnolipid BS. BS production by P. rhizophila S211 grown on olive mill wastewater based media was effectively optimized using a central-composite experimental design and response surface methodology (RSM). The optimum conditions for maximum BS production yield (720.80 ± 55.90 mg/L) were: 0.5% (v/v) inoculum size, 15% (v/v) olive oil mill wastewater (OMWW) and 40°C incubation temperature at pH 6.0 for 8 days incubation period. Biochemical and structural characterization of S211 BS by chromatography and spectroscopy studies suggested the glycolipid nature of the BS. P. rhizophila rhamnolipid was stable over a wide range of temperature (40-90°C), pH (6-10), and salt concentration (up to 300 mM NaCl). Due to its low-cost production, emulsification activities and high performance in solubilization enhancement of chemical pesticides, the indigenous BS-producing PGPR S211 could be used as a promising agent for environmental bioremediation of pesticide-contaminated agricultural soils.