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Search Results: 1 - 10 of 353 matches for " Amira Ghorbel "
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Harmonic Analysis in One-Parameter Metabelian Nilmanifolds
Amira Ghorbel
Symmetry, Integrability and Geometry : Methods and Applications , 2011,
Abstract: Let G be a connected, simply connected one-parameter metabelian nilpotent Lie group, that means, the corresponding Lie algebra has a one-codimensional abelian subalgebra. In this article we show that G contains a discrete cocompact subgroup. Given a discrete cocompact subgroup Γ of G, we define the quasi-regular representation τ=ind_Γ^G 1 of G. The basic problem considered in this paper concerns the decomposition of τ into irreducibles. We give an orbital description of the spectrum, the multiplicity function and we construct an explicit intertwining operator between τ and its desintegration without considering multiplicities. Finally, unlike the Moore inductive algorithm for multiplicities on nilmanifolds, we carry out here a direct computation to get the multiplicity formula.
Harmonic Analysis in One-Parameter Metabelian Nilmanifolds
Amira Ghorbel
Mathematics , 2011, DOI: 10.3842/SIGMA.2011.021
Abstract: Let $G$ be a connected, simply connected one-parameter metabelian nilpotent Lie group, that means, the corresponding Lie algebra has a one-codimensional abelian subalgebra. In this article we show that $G$ contains a discrete cocompact subgroup. Given a discrete cocompact subgroup $\Gamma$ of $G$, we define the quasi-regular representation $\tau = {\rm ind}_\Gamma^G 1$ of $G$. The basic problem considered in this paper concerns the decomposition of $\tau$ into irreducibles. We give an orbital description of the spectrum, the multiplicity function and we construct an explicit intertwining operator between $\tau$ and its desintegration without considering multiplicities. Finally, unlike the Moore inductive algorithm for multiplicities on nilmanifolds, we carry out here a direct computation to get the multiplicity formula.
Discrete Cocompact Subgroups of the Five-Dimensional Connected and Simply Connected Nilpotent Lie Groups
Amira Ghorbel,Hatem Hamrouni
Symmetry, Integrability and Geometry : Methods and Applications , 2009,
Abstract: The discrete cocompact subgroups of the five-dimensional connected, simply connected nilpotent Lie groups are determined up to isomorphism. Moreover, we prove if G = N × A is a connected, simply connected, nilpotent Lie group with an Abelian factor A, then every uniform subgroup of G is the direct product of a uniform subgroup of N and Z^r where r = dim A.
Discrete Cocompact Subgroups of the Five-Dimensional Connected and Simply Connected Nilpotent Lie Groups
Amira Ghorbel,Hatem Hamrouni
Mathematics , 2009, DOI: 10.3842/SIGMA.2009.020
Abstract: The discrete cocompact subgroups of the five-dimensional connected, simply connected nilpotent Lie groups are determined up to isomorphism. Moreover, we prove if $G=N\times A$ is a connected, simply connected, nilpotent Lie group with an Abelian factor $A$, then every uniform subgroup of $G$ is the direct product of a uniform subgroup of $N$ and ${\mathbb Z}^r$ where $r=\dim A$.
A Rare Cause of Lobular Panniculitis: Munchausen's Syndrome
Ajili Faida,Smiti Khanfir Monia,Hamzaoui Amira,Ben Ghorbel Imed,Lamloum Mounir,Houman Mohamed Habib
Case Reports in Medicine , 2012, DOI: 10.1155/2012/486421
Abstract: We describe a case of a 40-year-old woman who presented with ecchymoses of the right leg and who was found to have lobular panniculitis in biopsy due to Munchausen's Syndrome.
Potential Toxic Levels of Cyanide in Almonds (Prunus amygdalus), Apricot Kernels (Prunus armeniaca), and Almond Syrup
Nadia Chaouali,Ines Gana,Amira Dorra,Fathia Khelifi,Anouer Nouioui,Wafa Masri,Ines Belwaer,Hayet Ghorbel,Abderazzek Hedhili
ISRN Toxicology , 2013, DOI: 10.1155/2013/610648
Abstract: Under normal environmental conditions, many plants synthesize cyanogenic glycosides, which are able to release hydrogen cyanide upon hydrolysis. Each year, there are frequent livestock and occasional human victims of cyanogenic plants consumption. The present work aims to determine the hydrocyanic acid content in different samples of cyanogenic plants, selected from the Tunisian flora, and in the almond syrup. In order to evaluate their toxicity and their impact on the consumer health in the short term as well as in the long term, using the ISO 2164-1975 NT standard, relating to the determination of cyanogenic heterosides in leguminous plants. 1. Introduction Many plants synthesize compounds called cyanogenic glycosides, which are able to release hydrogen cyanide upon hydrolysis [1]. This ability, known as cyanogenesis, has been recognized for centuries in plants such as apricots, peaches, almonds, and other important food plants [2]. There are at least 2650 species of plants that produce cyanoglycosides. Once the edible parts of the plants are macerated, the catabolic intracellular enzyme -glucosidase can be released and can come into contact with the cyanogenic glycosides. This enzyme hydrolyzes the cyanogenic glycosides to produce hydrogen cyanide, glucose, ketones, or benzaldehyde [3]. Large numbers of people are daily exposed to low concentrations of cyanogenic compounds in many aliments, this exposition may imply a risk to human health. Each year, there are frequent livestock and occasional human victims of many and widespread cyanogenic plants consumption. Most cases of cyanide poisoning are caused by the consumption of the plants which are members of the Rosaceae, Euphorbiaceae, Fabaceae, or Gramineae family [4]. Released cyanide inhibits cellular respiration of all aerobic organisms by blocking mitochondrial electron transport and preventing oxygen uptake. High exposure to this potent poison in humans may cause nausea, vomiting, diarrhea, dizziness, weakness, mental confusion, and convulsions followed by terminal coma and literally death [5]. In many Tunisian regions, milled apricot kernels are widely used as a flavoring agent in pastries and cakes, while bitter almond is used to prepare traditional orgeat syrup (almond syrup) which is very popular and widely consumed in Tunisia. In this study, we aim to determine hydrocyanic acid content in different samples of cyanogenic plants. In order to evaluate their cyanogenic potential and their toxicity, according to ISO 2164-1975 NT standard, relating to the determination of cyanogenic heterosides in
ASIP Solution for Implementation of H.264 Multi Resolution Motion Estimation  [PDF]
Fethi Tlili, Akram Ghorbel
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.35060
Abstract: Motion estimation is the most important module in H.264 video encoding algorithm since it offer the best compression ratio compared to intra prediction and entropy encoding. However, using the allowed features for inter prediction such as variable block size matching, multi-reference frames and fractional pel search needs a lot of computation cycles. For this purpose, we propose in this paper an Application Specific Instruction-set Processor (ASIP) solution for implementing inter prediction. An exhaustive full and fractional pel combined with variable block size matching search are used. The solution, implemented in FPGA, offers both performance and flexibility to the user to reconfigure the search algorithm.
The Impact of Factors Related to the Audit of Financial Statements on Stock Returns: The Case of the Tunisian Market
Slim GHORBEL
International Journal of Economics and Finance , 2012, DOI: 10.5539/ijef.v4n4p163
Abstract: This paper focuses on the analysis of the reactions of stock prices following the announcement of financial statements. Our contribution is to study the importance of variables related to the audit in explaining the reactions of stock returns. On the theoretical level, we have based our study on the theory of market information efficiency, the agency theory, signaling theory and corporate governance. Empirically, we used the event study method to test for abnormal reactions in stock prices following the announcement of financial statements, on a sample of 48 Tunisian listed companies. Our results show that the audit quality, the auditor's opinion and the co-commissioning have a joint impact on the evolution of stock prices. However, the recurrence of audit engagement has no effect.
Energy β-Conformal Change and Special Finsler Spaces  [PDF]
Amr Soleiman, Amira A. Ishan
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.47132
Abstract:

The main aim of the present paper is to establish an intrinsic investigation of the energy β-conformal change of the most important special Finsler spaces, namely, Ch-recurrent, Cv-recurrent, C0-recurrent, Sv-recurrent, quasi-C-reducible, semi-C-reducible, C-reducible, P-reducible, C2-like, S3-like, P2-like and h-isotropic, ···, etc. Necessary and sufficient conditions for such special Finsler manifolds to be invariant under an energy β-conformal change are obtained. It should be pointed out that the present work is formulated in a prospective modern coordinate-free form.

The Psychological Profile of Youth Male Soccer Players in Different Playing Positions  [PDF]
Amira Najah, Riadh Ben Rejeb
Advances in Physical Education (APE) , 2015, DOI: 10.4236/ape.2015.53020
Abstract: The purpose of this study was to investigate selected psychological skills of male youth soccer players in different playing positions. This study examined possible positional differences of 180 male youth Tunisian soccer players between the ages of 15 and 19 years old from different clubs of 1st and 3rd Youth Class divisions. The subjects were divided into three playing positions, namely, forward (n = 60), midfield (n = 60) and defense (n = 60), and compared with regard to twelve psychological skills measured by means of the Ottawa Mental Skills Assessment Tool (OMSAT-3) of Durand Bush et al. (2001). Results yielded significant differences between basic and psychosomatic subscale scores of the players in different playing positions. Forward players consistently outperformed the other positional groups in motivation, confidence and activation. Defense players outperformed the other positional groups in relaxation, while midfield players showed the lowest psychological skill levels. The results of the study provided support for the hypothesis that positional differences in terms of psychological skills existed. More specifically, statistical evidence suggested that youth soccer players could be differentiated as a function of psychological skill and the position that they played on the team.
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