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OALib Journal期刊

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匹配条件: “ Lamine Ossama” ,找到相关结果约211条。
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Evaluation of Cardiovascular Risk Factors in Tunisian Coronary Patients  [PDF]
Grira Nadra, Sandesni Rihab, Lamine Ossama, Aboulkassem Sana, Ayoub Manel, El Oudi Mabrouka, Stambouli Najla, Lahidheb Thaker, Haouala Habib, Mazigh Chakib, Aouni Zied
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104214
Abstract:
Introduction: Ischemic heart disease ranked among the leading causes of death worldwide. Several biological and genetic risk factors associated with acute coronary syndrome. By addressing the risk factors, it is possible to prevent most of the cardiovascular diseases and contribute to the reduction of complications of acute coronary syndrome. Material and Methods: Our study is a prospective study that was conducted to the main military hospital of instruction of Tunis. Recruitment involved 122 coronary (n = 122) and 705 controls (n = 705) totaling a population of 827 subjects. Data collection concerned socio-demographic characteristics, anthropometric measurements, habits and lifestyle, health status and biological assessment. Results: Our study reported a high prevalence of cardiovascular classic risk factor particularly overweight (62.3%), diabetes (63.1%) and hypertension (50%). In 55% of coronary patients, moderate to intermediate hyperhomocysteinemia was found, but it appears to be an independent risk factor. The results of our study show a significant difference in the genotypic frequencies of the C677T mutation in the MTHFR gene between the two populations, cases and controls. Conclusion: Acute coronary syndromes are the leading cause of sudden death in adults. The evaluation of risk factors after acute coronary syndrome episode is essential for a better management according to the recommendations of learned societies and standards of good practice.
Relativistic Time-Dependent Density Functional Theory and Excited States Calculations for the Zinc Dimer
Ossama Kullie
Journal of Atomic, Molecular, and Optical Physics , 2012, DOI: 10.1155/2012/361947
Abstract: I present a time-dependent density functional study of the 20 low-lying excited states as well the ground states of the zinc dimer Zn2, analyze its spectrum obtained from all electrons calculations performed using time-depended density functional with a relativistic 4-component and relativistic spin-free Hamiltonian as implemented in Dirac-Package, and show a comparison of the results obtained from different well-known and newly developed density functional approximations, a comparison with the literature and experimental values as far as available. The results are very encouraging, especially for the lowest excited states of this dimer. However, the results show that long-range corrected functionals such as CAMB3LYP gives the correct asymptotic behavior for the higher states, and for which the best result is obtained. A comparable result is obtained from PBE0 functional. Spin-free Hamiltonian is shown to be very efficient for relativistic systems such as Zn2.
Autonomous Planning of Multigravity-Assist Trajectories with Deep Space Maneuvers Using a Differential Evolution Approach
Ossama Abdelkhalik
International Journal of Aerospace Engineering , 2013, DOI: 10.1155/2013/145369
Abstract: The biologically inspired concept of hidden genes has been recently introduced in genetic algorithms to solve optimization problems where the number of design variables is variable. In multigravity-assist trajectories, the hidden genes genetic algorithms demonstrated success in searching for the optimal number of swing-bys and the optimal number of deep space maneuvers. Previous investigations in the literature for multigravity-assist trajectory planning problems show that the standard differential evolution is more effective than the standard genetic algorithms. This paper extends the concept of hidden genes to differential evolution. The hidden genes differential evolution is implemented in optimizing multigravity-assist space trajectories. Case studies are conducted, and comparisons to the hidden genes genetic algorithms are presented in this paper. 1. Introduction A fundamental step in the planning of interplanetary space missions is the design of the spacecraft trajectory. The multigravity-assist trajectory with deep space maneuvers (MGADSMs) is a trajectory that benefits from the gravitational fields of other planets to attain a free momentum change, by performing swing-bys around the planets. MGADSM trajectories can also use impulsive thrust to apply deep space maneuvers (DSMs) as needed. A criterion that is usually used in designing the MGADSM trajectory is to find the MGADSM trajectory that has minimum fuel expenditure. Designing the MGADSM trajectory is then formulated as an optimization problem. The design parameters that need to be optimized are the number of swing-bys, the planets to swing by, the times of swing-bys, the number of DSMs, the components and directions of these DSMs, the times at which these DSMs are applied, and the exact launch and arrival dates. This optimization problem, in its general form, is a variable-length optimization problem where the number of design variables is a variable. For instance, one solution may have 2 DSMs, and another solution for the same problem may have 3 DSMs. The number of design variables is different in both cases. The different number of swing-bys also causes the number of design variables to vary among different solutions. Several optimization approaches have been proposed to solve the MGADSM trajectory design problem. Reference [1] developed a deterministic search space pruning algorithm to search for the optimal solution for a simplified version of the problem. When the gravity-assist sequence (i.e., the number of swing-bys and the planets to swing by) is known a priori, and assuming no
Relativistic Time-Dependent Density Functional Theory and Excited States Calculations for the Zinc Dimer
Ossama Kullie
Journal of Atomic and Molecular Physics , 2012, DOI: 10.1155/2012/361947
Abstract: I present a time-dependent density functional study of the 20 low-lying excited states as well the ground states of the zinc dimer Z n 2 , analyze its spectrum obtained from all electrons calculations performed using time-depended density functional with a relativistic 4-component and relativistic spin-free Hamiltonian as implemented in Dirac-Package, and show a comparison of the results obtained from different well-known and newly developed density functional approximations, a comparison with the literature and experimental values as far as available. The results are very encouraging, especially for the lowest excited states of this dimer. However, the results show that long-range corrected functionals such as CAMB3LYP gives the correct asymptotic behavior for the higher states, and for which the best result is obtained. A comparable result is obtained from PBE0 functional. Spin-free Hamiltonian is shown to be very efficient for relativistic systems such as Zn2. 1. Introduction Zinc dimer Z n 2 is the first member of the group 12 (IIB) ( Z n 2 , C d 2 , H g 2 , and C n 2 ) and has a representative character of these dimers. The interest in the dimers of the group IIB ( 1 2 ) is in part due to the possibility of laser applications in analogy with the rare gas dimers. A second point is the importance of the metallic complexes similar to the transition metal complexes [1–4] and some important application like the solar cell and renewable energy [5, 6] as well as electric battery for new cars technology [7, 8]. Z n 2 , C d 2 , and H g 2 are exciter with a shallow, predominantly Van der Waals ground state and low-lying covalent bound excited states. They are also interesting from a theoretical point of view due to the different character of the ground and excited states and consequently the different methodological demands for an accurate theoretical description of the spectrum. The dimer of group 12 has been studied both experimentally and theoretically. Relevant reviews have been provided by Morse [9] and more recently by Koperski [10, 11]. The covalent contributions to the ground state bonding in the group 12 dimers have been investigated in [12], it was concluded that the bond is a mixture of 3/4 Van der Waals and 1/4 covalent interactions. Bucinisky et al. [13] provides spectroscopic constants using the coupled cluster method (CCSD(T)) and different level of the theory 4-component relativistic Hamiltonian, using Dirac-Coulomb Hamiltonian, relativistic spin-free Hamiltonian and nonrelativistic (NR) Hamiltonian. Furthermore, they investigated the
Tunneling time in attosecond experiments, Keldysh, Mandelstam-Tamm and intrinsic-type of time
Ossama Kullie
Physics , 2015,
Abstract: Tunneling time in attosecond and strong field experiments is one of the most controversial issues in today's research, because of its importance to the theory of time, the time operator and the time-energy uncertainty relation in quantum mechanics. In [1] we derived an estimation of the (real) tunneling time, which shows an excellent agreement with the time measured in attosecond experiments, our derivation is found by utilizing the time-energy uncertainty relation, and it represents a quantum clock. In this work, we show different aspects of the tunneling time in attosecond experiments, we discuss and compare the different views and approaches, which are used to calculate the tunneling time, i.e. Keldysh time (as a real or imaginary quantity), Mandelstam-Tamm time and our tunneling time relation(s). We draw some conclusion concerning the validity and the relation between the different types of the tunneling time with the hope, it will help to answer the the question put forward by Orlando et al [2] tunneling time, what does it mean?. In respect to our result, the time in quantum mechanics can be, in more general fashion, classified in two types, intrinsic dynamically connected, and external dynamically not connected, to the system.
Bottleneck Merge Control Strategies for Work Zones: Available Options and Current Practices  [PDF]
Ossama E. Ramadan, Virginia P. Sisiopiku
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.54043
Abstract: Maintenance and rehabilitation projects of interstate facilities typically mandate lane closures. Lane closures require merging maneuvers that often result in reduced speeds and traffic bottlenecks. Conventionally, bottleneck merge control plans are developed to address bottlenecks impacts. However, there is a need to better understand the various merge control options and their potential impacts on traffic operations and safety. This study reviewed available options and current practices of bottleneck merge control strategies at work zones, and summarized transportation agencies’ considerations to mitigate adverse impacts. An extensive literature review was performed and a questionnaire survey was developed and used to gather relevant information. Input was solicited from all US State Departments of Transportation. Responses from 27 States revealed that transportation agencies currently rely on experience when selecting a bottleneck merge control strategy and often do not consider influence on construction activities. Thus, a gap was identified between bottleneck merge control and construction plans. Another gap was identified regarding the lack of formal criteria or guidelines for selecting a bottleneck merge control strategy. These gaps need to be addressed through investigating the influence of bottleneck merge control strategies on construction activities, and the development of formal criteria for effective selection of such strategies.
Repeated Shadow Track Orbits for Space-SunSetter Missions
Ahmed Gad,Ossama Abdelkhalik
International Journal of Aerospace Engineering , 2009, DOI: 10.1155/2009/561495
Abstract: This paper introduces a new set of orbits, the “Repeated Shadow Track Orbits.” In these orbits, the shadow of a spacecraft on the Earth visits the same locations periodically every desired number of days. The 2 perturbation is utilized to synchronize the spacecraft shadow motion with both the Earth rotational motion and the Earth-Sun vector rotation. Motivation for the design of new shadow track orbits comes from the need to save energy. The general mathematical model to design a Repeated Shadow Track Orbit (RSTO) is presented within this paper. RSTOs' conditions are formulated and numerically solved. Results show the feasibility of RSTOs. An optimization process is also developed to maximize the shadow duration over a given site. A Genetic Algorithm (GA) technique is utilized for optimization.
3D Surface Roughness Measurement Using a Light Sectioning Vision System
Ossama B. Abouelatta
Lecture Notes in Engineering and Computer Science , 2010,
Abstract:
Thrombolytic Therapy for Acute Stroke: The Hidden Dimension
Ossama Mansour,Martin Schumacher
Frontiers in Neurology , 2010, DOI: 10.3389/fneur.2010.00126
Abstract:
Corps et esprit : l’identité humaine selon Spinoza
Lamine Hamlaoui
Astérion , 2005,
Abstract: Contrairement à Descartes, Spinoza refuse à l’esprit humain et par conséquent à l’homme le statut de substance : l’homme est défini comme l’union de deux modes, un corps et une ame. On ne peut donc plus comme chez Descartes distinguer une identité substantielle, conférée au corps par l’ame, et une identité modale, déterminée par le rapport du corps humain aux autres corps. Ces deux identités sont fondues dans une identité essentielle. L’objet de cet article est de mettre en évidence le statut problématique de cette identité dans l’éthique. L’esprit humain y est en effet déduit et défini comme l’idée du corps humain, c’est-à-dire le concept que Dieu forme du corps humain. Mais tant t Spinoza identifie cette idée du corps humain à l’essence de l’esprit humain, tant t il établit une distinction entre les deux. De même, tant t en vertu du parallélisme des attributs il identifie l’idée du corps humain à l’idée de l’esprit humain, tant t il distingue les deux. D’où des tensions qui travaillent le système de l’intérieur. Contrary to Descartes, Spinoza refuses to human mind and therefore to man the status of substance : man is defined as the union of two modes, body and mind. We can’t distinguish, as in Descartes, a substantial identity, conferred to the body by the mind, and a modal identity, determined by the relation between human body and other bodies. Both identities form an essential identity. This paper explains the problematical character of this identity in Spinoza’s Ethic. Human mind is indeed deduced and defined as the idea of human body, namely the concept of human body formed by God. But sometimes Spinoza identifies the idea of human body with the essence of human body, sometimes he makes a distinction between both. In the same way, sometimes he identifies the idea of human body with the idea of human mind, in accordance with parallelism of attributes, sometimes he distinguishes both. We can see, therefore, internal tensions in the system.
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