Dridi I.,Tunis el Manar University |
Arfaoui A.,Jendouba University
Environmental Earth Sciences | Year: 2017
The study of nitrogen organic matter is of great importance for both economic and environmental reasons. Thus, seven soils developed under different pedogenetic and bioclimatic conditions in Tunisia were selected to investigate the distribution of organic nitrogen (ON). Our results showed an enrichment in ON of superficial horizons to the detriment of the deep horizons. Nevertheless, this decrease in ON contents with depth occurred following different patterns according to soil type. Moreover, the investigation of ON distribution in clay- and silt-sized particles (below 50 µm) indicated a considerable contribution of the fine fraction (65–98% of the soil total ON) to the ON immobilization in soils, especially in the deep horizons, while the coarse fraction (>50 µm) seems to play a less important role. The isolation of humic substances (Humic Acids, Fulvic Acids and Humin (H)) from the fine fraction and the analysis of the ON in each of these organic fractions permitted to conclude the majority of soil ON is incorporated within the H, thus suggesting a low bioavailability of nitrogen in the studied soils. © 2017, The Author(s).
Alimi N.,Tunis el Manar University |
Aflouk N.,Jendouba University
Journal of International Trade and Economic Development | Year: 2017
This paper investigates the relationship between terms-of-trade shocks and macroeconomic volatility for a panel of 58 developing countries from 1980 to 2015. Using a Panel Smooth Transition Regression model, we prove first, that terms-of-trade volatility have a statistically significant and positive impact on the volatility of output growth, although the magnitude of this effect is not the same by the report to the threshold that has been identified. Second, the terms-of-trade volatility affect macroeconomic fluctuation differently depending on whether the country is a net exporter of the commodity, fuel or manufactured goods. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Ltifi M.,University of Sfax |
Gharbi J.-E.,Jendouba University
Journal of Internet Banking and Commerce | Year: 2012
The objective of this research is to study the impact of emotional state and perceived risk of remote purchase on e-satisfaction during the Internet shopping. As well, it aims to study the influence of e-satisfaction on e-loyalty. The data gathering was carried out by a laboratory experiment followed by a questionnaire. The results show that three dimensions of the emotional state during Internet shopping (the pleasure, stimulation and dominance) have a significant positive impact on e-satisfaction. Dimensions of the perceived risk of remote purchase, (the total risk, the financial risk, the social risk, the psychological risk, the functional risk, and the physical risk) don't have a significant impact on e-satisfaction, except the risk of loss of time has a negative impact. Finally esatisfaction influences positively and significantly the e-loyalty of the cyber consumers. © Moez Ltifi and Jamel-Eddine Gharbi, 2012.
Chaabene H.,Tunisian Research Laboratory Sport Performance Optimization |
Franchini E.,University of Sao Paulo |
Miarka B.,University of Sao Paulo |
Selmi M.A.,Jendouba University |
And 2 more authors.
International Journal of Sports Physiology and Performance | Year: 2014
Purpose: The aim of this study was to measure and compare physiological and time-motion variables during karate fighting and to assess eventual differences between winners and defeated elite karatekas in an ecologically valid environment. Methods: Fourteen elite male karatekas who regularly participated in national and international events took part in a national-level competition. Results: There were no significant differences between winners and defeated karatekas regarding all the studied variables. Karatekas used more upper-limb (76.19%) than lower-limb techniques (23.80%). The kisami-zuki represented the most frequent technique, with 29.1% of all used techniques. The duration of each fighting activity ranged from <1 s to 5 s, with 83.8% ± 12.0% of the actions lasting less than 2 s. Karatekas executed 17 ± 7 high-intensity actions per fight, which corresponded to ~6 high-intensity actions per min. Action-to-rest ratio was about 1:1.5, and high-intensityaction-to-rest ratio was ~1:10. The mean blood lactate response at 3 min postcombat (Lapost) elicited during karate fighting was 11.18 ± 2.21 mmol/L (difference between Lapre and Lapost = 10.01 ± 1.81 mmol/L). Mean heart rate (HR) was 177 ± 14 beats/min (91% ± 5% of HRpeak). Karatekas spent 65% of the time exercising at HR >90% of the individual HRpeak. Conclusion: Karatekas predominantly use upper-limb karate techniques. Karate's nature is intermittent, with fighting activities representing ~6% of total combat's duration and ~84% of actions lasting less than 2 s, with ~21-s mean time interval in between. Kumite combat sessions induced high La and near-maximal cardiovascular strain. Other key success factors should be investigated to properly discriminate winners and defeated athletes. © 2014 Human Kinetics, Inc.
Krichen S.,University of Tunis |
Krichen S.,Jendouba University |
Laabidi A.,University of Tunis |
Abdelaziz F.B.,American University of Sharjah
Computers and Industrial Engineering | Year: 2011
We consider in this paper an Economic Order Quantity (EOQ) problem involving a single supplier that offers quantity discounts and allows retailers to delay payments. The retailers are tempted to form coalitions in order to minimize their costs. We propose a solution approach that generates stable coalition structures for the retailers taking into account the delay in payments and the discount quantity offered by the supplier. The proposed approach includes a decision rule that generates preferred coalitions for each retailer. Our decision rule reduces considerably the number of explored coalition structures in order to determine solutions in the core. Through an experimental investigation of the problem, we show the effectiveness of our approach in solving large scale problems and illustrate the effect of permissible delay in payments versus discount quantity on the coalition formation problem. © 2010 Elsevier Ltd. All rights reserved.
Ben Aissa M.S.,Tunis el Manar University |
Ben Jebli M.,Tunis el Manar University |
Ben Jebli M.,Jendouba University |
Ben Youssef S.,Manouba University
Energy Policy | Year: 2014
We use panel cointegration techniques to examine the relationship between renewable energy consumption, trade and output in a sample of 11 African countries covering the period 1980-2008. The results from panel error correction model reveal that there is evidence of a bidirectional causality between output and exports and between output and imports in both the short and long-run. However, in the short-run, there is no evidence of causality between output and renewable energy consumption and between trade (exports or imports) and renewable energy consumption. Also, in the long-run, there is no causality running from output or trade to renewable energy. In the long-run, our estimations show that renewable energy consumption and trade have a statistically significant and positive impact on output. Our energy policy recommendations are that national authorities should design appropriate fiscal incentives to encourage the use of renewable energies, create more regional economic integration for renewable energy technologies, and encourage trade openness because of its positive impact on technology transfer and on output. © 2013 Elsevier Ltd.
Ben Jebli M.,Jendouba University
Environmental Science and Pollution Research | Year: 2016
This study employs the autoregressive distributed lag (ARDL) approach and Granger causality test to investigate the short- and long-run relationships between health indicator, real GDP, combustible renewables and waste consumption, rail transport, and carbon dioxide (CO2) emissions for the case of Tunisia, spanning the period of 1990–2011. The empirical findings suggest that the Fisher statistic of the Wald test confirm the existence of a long-run relationship between the variables. Moreover, the long-run estimated elasticities of the ARDL model provide that output and combustible renewables and waste consumption have a positive and statistically significant impact on health situation, while CO2 emissions and rail transport both contribute to the decrease of health indicator. Granger causality results affirm that, in the short-run, there is a unidirectional causality running from real GDP to health, a unidirectional causality from health to combustible renewables and waste consumption, and a unidirectional causality from all variables to CO2 emissions. In the long-run, all the computed error correction terms are significant and confirm the existence of long-run association among the variables. Our recommendations for the Tunisian policymakers are as follows: (i) exploiting wastes and renewable fuels can be a good strategy to eliminate pollution caused by emissions and subsequently improve health quality, (ii) the use of renewable energy as a main source for national rail transport is an effective strategy for public health, (iii) renewable energy investment projects are beneficial plans for the country as this contributes to the growth of its own economy and reduce energy dependence, and (iii) more renewable energy consumption leads not only to decrease pollution but also to stimulate health situation because of the increase of doctors and nurses numbers. © 2016 Springer-Verlag Berlin Heidelberg
Djebali R.,Jendouba University
Communications in Computational Physics | Year: 2014
This study aims to investigate turbulent plasma flow using the lattice Boltzmann (LB) method. A double population model D2Q9-D2Q4 is employed to calculate the plasma velocity and temperature fields. Along with the calculation process a conversion procedure is made between the LB and the physical unit systems, so that thermo-physical properties variation is fully accounted for and the convergence is checked in physical space. The configuration domain and the boundary condition treatment are selected based on the most cited studies in order to illustrate a realistic situation. The jet morphology analysis gives credible results by comparison with commonly published works. It was demonstrated also that accounting for the substrate as wall boundary condition modify greatly the flow and temperature structures with may affect absolutely the particles behavior during its in-flight in the hot gas. © 2014 Global-Science Press.
Djebali R.,Jendouba University
CFD Letters | Year: 2014
In this letters we’ll present some comments concerning the paper entitled ‘Lattice Boltzmann Analysis of 2-D Natural Convection Flow and Heat Transfer within Square Enclosure Including an Isothermal Hot Block’ published in International Journal of Thermal Technologies (IJTT), vol. 3(4), pp. 146-154 (2013) by T. Naffouti, J. Zinoubi and R. Ben-Maad. The papers discusses laminar natural convection problem within square enclosure using a thermal lattice Boltzmann (LB) model. So that the comments drawn here are related especially to the lattice Boltzmann standards (norms) and the numerical parameters influencing the accuracy of the presented results such in particular the computed Nusselt number. © 2014 All rights reserved. ISSR Journals.
Mezni H.,Jendouba University
Proceedings of the IEEE International Conference on Software Engineering and Service Sciences, ICSESS | Year: 2014
Although several approaches have been proposed towards self-adaptation of Web services, most of them work in isolation and few of them deal with cross-layer and trust issues. Indeed, the complex layered nature of service-based systems frequently leads to service failure and conflicting adaptation. To tackle this problem, we propose an ontology-based categorization of service behavior across all the functional layers. The proposed ontology provides support for cross-layer self-adaptation by facilitating reasoning about events to identify the real source of service failure, and reasoning about self-adaptation actions to check integrity and compatibility of self-adaptation with constraints imposed by each layer. © 2014 IEEE.