Gouvernement d’entreprise et contenu informationnel du résultat comptable : Etude empirique dans le contexte français

Le conseil d’administration est considéré comme une des composantes importantes des mécanismes internes de gouvernement d’entreprise. Les recherches dans ce domaine ont porté, entre autres, sur la structure du conseil ainsi que sur sa composition. Menée sur un échantillon de 71 entreprises françaises cotées en bourse, cette étude examine les effets concomitants de certaines caractéristiques aussi bien du conseil d'administration que du comité d'audit sur le contenu informationnel du résultat comptable dans la période post-IFRS. Les résultats obtenus indiquent que l'indépendance des administrateurs en général, et des membres du comité d'audit en particulier, ainsi que la taille du conseil d'administration constituent des éléments clés pour un contrôle efficace sur le processus d’établissement des états financiers, et par conséquent l'obtention d'un résultat comptable plus informatif

Modeling, Development and Analysis Performance of an Intelligent Control of Photovoltaic System by Fuzzy Logic approach for Maximum Power Point Tracking

In this paper, we present an intelligent algorithm based upon Fuzzy Logic method for optimizing and improving the control performance of a   photovoltaic system. The main objective of the proposed system is to pursuit the maximum power point (MPPT) under different conditions like the change of sunshine and temperature. The system consists of a photovoltaic solar module connected to a DC-DC step-up converter "Boost" and a battery - like a load . The converter parameters and the inference rule table are determined to ensure maximum output power. The effectiveness of the proposed system is validated through computer simulations using MATLAB / Simulink software and the obtained results shows that our proposed system has the best performance in term maximum power

Design, optimization and Real Time implementation of a new Embedded Chien Search Block for Reed-Solomon (RS) and Bose-Chaudhuri-Hocquenghem (BCH) codes on FPGA Board

The development of error correcting codes has been a major concern for communications systems. Therefore, RS and BCH (Reed-Solomon and Bose, Ray-Chaudhuri and Hocquenghem) are effective methods to improve the quality of digital transmission. In this paper a new algorithm of Chien Search block for embedded systems is proposed. This algorithm is based on a factorization of error locator polynomial. i.e, we can minimize an important number of logic gates and hardware resources using the FPGA card. Consequently, it reduces the power consumption with a percentage which can reach 40 % compared to the basic RS and BCH decoder. The proposed system is designed, simulated using the hardware description language (HDL) and Quartus development software. Also, the performance of the designed embedded Chien search block for decoder RS\BCH (255, 239) has been successfully verified by implementation on FPGA board

PERFORMANCE COMPARISON OF NEW DESIGNS OF CHIEN SEARCH AND SYNDROME BLOCKS FOR BCH AND REED SOLOMON CODES

Error correcting codes constitute one of the core technologies in telecommunications field, especially digital communication applications. The objective of this paper is to compare performance among new designs of chien search block on the one hand and syndrome architectures on the other hand in error correcting codes. All comparison of all designs is made by computing the number of logic, bit error rate values and number of iteration in the case of syndrome architectures Analysis results show that the performances of the new designs based on both second factorization method and Three-Parallel Syndrome architecture are superior to the performances of traditional designs

Resistance development and insecticide susceptibility in Culex pipiens pipiens, an important vector of human diseases, against selection pressure of temephos and its relationship to cross-resistance towards organophosphates and pyrethroids insecticides

Background: Culex pipiens pipiens is an important vector of human diseases. Objective: To determine the insecticide resistance development in Culex pipiens pipiens against selection pressure of temephos.. Methods: A field population of Culex pipiens pipiens was collected from Northwestern Tunisia with a medium level of temephos resistance (LC50 = 0.0069). It was subjected to six generations of temephos pressure selection to evaluate its relationship to cross-resistance towards organophosphates (OPs) and pyrethroids (PYR) insecticides. Results: The selection was initiated at the dose 0.0266, 0.0748 and 0.0069 which were increased during successive generations up to 0.1488, 3.8747 and 0.0086 after sixth generation for temephos, chlorpyrifos and permethrin insecticides, respectively. It is important to noted that high cross-resistance to chlorpyrifos insecticide (OP) was detected (51.88 7). However, little or no cross-resistance to the pyrethroid permethrin (PYR) was recorded (1.24 7). Contrary to metabolic resistance, it seemed that acetylcholinesterases AChE 1 was fixed under pressure selection. Conclusion: The high cross-resistance to temephos and chlorpyrifos is reasonable because they belong to the same class of insecticide (OP). However, the little cross-resistance to the pyrethroid permethrin could support its use alternately for Culex pipiens pipiens control

Evaluation of resistance to temephos insecticide in Culex pipiens pipiens larvae collected from three districts of Tunisia

Background: Mosquitoes are considered as the main groups of arthropods that cause nuisance and public health problems. Objectives: Evaluation of resistance to temephos insecticide in Culex pipiens pipiens larvae collected from three districts of Tunisia. Methods: Late third and early fourth instars larvae of Culex pipiens pipiens were collected in three localities of Northern and Southern Tunisia. Field collected populations were tested against temephos insecticide and compared to bioassays of a susceptible reference strain. The cross-resistance between temephos and propoxur, and the polymorphism of over-produced esterases and AChE 1 were investigated. Results: Studied populations exhibited tolerance to temephos with low and high levels of resistance. The resistance ratio (RR50) values of temephos ranged from 1.34 to 114. Synergists and starch electrophoresis showed that the metabolic resistances were involved in the recorded resistance. Likewise, the resistant target site (acetyl cholinesterase: AChE 1) was responsible for the recorded resistance to temephos compound in Culex pipiens pipiens. Conclusion: The low and high resistance recorded to temephos insecticides is particularly interesting, because it leaves a range of tools useable by vector control services. However, further studies are needed to determine its spread and anticipate vector control failure where these insecticides are used. DOI: https://dx.doi.org/10.4314/ahs.v19i1.8 Cite as: Tabbabi A, Daaboub J, Laamari A, Cheikh RB, Feriani M, Boubaker C, Jha IB, Cheikh HB. Evaluation of resistance to temephos insecticide in Culex pipiens pipiens (Diptera: Culicidae) larvae collected from three districts of Tunisia. Afri Health Sci. 2019;19(1): 1361-1367. https://dx.doi.org/10.4314/ahs.v19i1.

Resistance status to deltamethrin pyrethroid of Culex pipiens pipiens (Diptera: Culicidae) collected from three districts of Tunisia

Objectives: The aim of the present study was to determine the susceptibility status of Culex pipiens pipiens populations against deltamehtrin insecticide. Methods: Larvae of Culex pipiens pipiens were collected from three breeding places in Northern and Southern Tunisia between 2003 and 2005. Early third and late fourth instars were tested against deltamethrin pyrethroid insecticide. Cross-resistance with DDT resistance was evaluated in studied samples to estimate the role of target site insensitivity and two synergists including piperonyl butoxide (Pb) and S,S,S-tributyl phosphorotrithioate (DEF) were used to estimate the role of detoxification enzymes. Results: Our results revealed that the level of deltamehtrin resistance ranged from 0.67 to 31.4. We also showed the non-involvement of kdr resistance in pyrethroid resistance and no cross-resistance with DDT resistance was detected in all studied populations including the most resistant one. Synergists study on the resistant population (sample # 1) showed the involvement of CYP450 in the recorded resistance to the deltamethrin insecticide. Conclusion: The results obtained from this study should be considered in the current control programs to combat mosquitoes in Tunisia

A Robust Embedded Non-Linear Acoustic Noise Cancellation (ANC) Using Artificial Neural Network (ANN) for Improving the Quality of Voice Communications

Embedded Acoustic Noise Cancellation (ANC) has enjoyed remarkable success in the telecommunication field, and it becomes an essential component in various communications applications, such as digital transmission. So, it is an efficient method used to enhance the quality of communications against noise phenomena which is a problem in communication systems. This paper contributes towards a new non-linear embedded ANC based Artificial Neural Network (ANN) in digital signal processing and backpropagation (BP) of the gradient algorithm. This system is usually required for non-linear adaptive processing digital signals. The neuronal ANC estimates the noise path and subtracting noise from a received signal by minimizing a cost function. It is the mean square error. Thus, also the filter weights are adaptively updated. In this work, we designed and simulated our intelligent embedded ANC model with the help of MATLAB\Simulink software. The proposed system was designed by using embedded functions in Simulink. In addition, all simulation results are performed and verified using Signal Noise to Ratio (SNR) and Mean Square Error (MSE), number of iteration, neuronal architecture, criteria and it has been compared in various scenarios.  Finally, a study and analysis on convergence of neuronal ANC based backpropagation of the gradient algorithm demonstrate that our proposed system can effectively improve the quality of voice communications against the undesired noise. It also provides faster convergence during the back propagation of the gradient. Furthermore, the best values of SNR and MSE show the effectiveness of the proposed model