89 research outputs found
Soil-Plant Interface, Carbon Sequestration and the Eco physiological Growth of Salsola Imbricata and Zygophyllum Mandaville Using Locally Grown Rhizosphere and Endophytic Bacteria
Salsola imbricata and Zygophyllum Mandeville are halophytic plants available widely in the UAE. These two species have important environmental services such as sand dune fixation, which will potentially improve plant cover and help tackle the problem of desertification. The species were selected due to their availability and role in the desert environment of the UAE. Plants are also constantly involved in interactions with a wide range of bacteria in the soil. These plant-associated bacteria colonize the rhizosphere (rhizobacteria), and the internal plant tissues (bacterial endophytes). Endophytic bacteria are those capable of colonizing live internal plant tissues which can be isolated from surface-disinfested plant material, and that does not visibly harm the host plant. In the present thesis, Salsola imbricata and Zygophyllum Mandeville were cultivated with or without the incorporation of plant growth promoting soil and endophytic bacteria that were obtained from Salsola imbricata and Zygophyllum Mandaville roots and soil. These plant growth-promoting bacteria were selected based on their abilities to produce plant growth regulators such as auxins, polyamines and in addition to their abilities to fix nitrogen and to solubilize phosphorus. The aim of the present work was to examine if these bacteria can promote Salsola imbricata and Zygophyllum Mandaville growth without using large quantities of water, and the plants’ carbon sequestration potentials. The plant species physiological growth pattern was closely monitored. The inoculation was effective in some growth parameters in both species after the application of treatment. Inoculated Salsola imbricata plants had larger root weight than control plants after four months of treatment, 0.50 g and 0.23 g respectively. Results from the current study state that inoculated soils had more activity than the control ones even after four months of inoculation, meaning that the inoculation was successful and effective.
However, significant changes in all physiological and morphological parameters were not observed. The parameters improved by inoculation include green shoot weight, root length, dry root and shoot weight, and chlorophyll conten
Deswelling of Hydrogels in Aqueous and Polyethylene Glycol Solutions. A New Approach for Drug Delivery Application
To enhance the properties of pure poly(acrylamide) hydrogel, diprotic maleic acid co-monomer was included into the reaction mixture during hydrogel synthesis. These hydrogels have been shown important swelling in distilled water and deswelling in acidic solution. In present work, we based on these considerations to study the deswelling behaviour of poly(acrylamide-co-maleic acid) hydrogels in different media (air, polyethylene glycol 200 (PEG200), acidic solution). Hydrogels of poly(acrylamide) and its copolymers with maleic acid were prepared by copolymerization and chemical crosslinking with methylene bisacrylamide. The obtained hydrogels have shown substantial mass swelling in distilled water and shrinking in acidic solution and PEG200. Results showed that the PEG200 was a better solvent for hydrogel deswelling and possibly will be used for gel drying. The swelling and deswelling kinetics were described by second-ordered and first-ordered models, respectively. BSA desorption in PEG200 was also studied
Linear lexicographic optimization and preferential bidding system
Some airlines use the preferential bidding system to construct the schedules
of their pilots. In this system, the pilots bid on the different activities and
the schedules that lexicographically maximize the scores of the pilots
according to their seniority are selected. A sequential approach to solve this
maximization problem is natural: the problem is first solved with the bids of
the most senior pilot; then it is solved with those of the second most senior
without decreasing the score of the most senior, and so on. The literature
admits that the structure of the problem somehow imposes such an approach. The
problem can be modeled as an integer linear lexicographic program. We propose a
new exact method, which relies on column generation for solving its continuous
relaxation. To design this column generation, we prove that bounded linear
lexicographic programs admit "primal-dual" feasible bases and we show how to
compute such bases efficiently. Another contribution on which our exact method
relies consists in the extension of standard tools for resource-constrained
longest path problems to their lexicographic versions. This is useful in our
context since the generation of new columns is modeled as a lexicographic
resource-constrained longest path problem. Numerical experiments show that this
new method is already able to solve industrial instances provided by Air
France, with up to 150 pilots. By adding a last ingredient in the resolution of
the longest path problems, which exploits the specificity of the preferential
bidding system, the method achieves for these instances computational times
that are compatible with operational constraints
Air traffic conflict resolution via light propagation modeling
The analysis of air traffic growth expects a doubling in the flights number over the next 20 years. The Air Traffic Management (ATM) will therefore have to absorb this additional burden and to increase the airspace capacity, while ensuring at least equivalent standards of safety. The European project SESAR was initiated to propose solutions to this problem. It relies on a new concept of air traffic control, known as 4D (3D + time) trajectory planning, which consists in exploiting the new Flight Management System (FMS) abilities that ensure that the aircraft is at a given position at a given moment. For each flight, a reference trajectory, called Reference Business Trajectory (RBT), is requested by the operating airline. During the flight, conflict situations may nevertheless occur, in which two or several aircraft can dangerously approach each other. In this case, it is necessary to modify one or more trajectories to ensure that minimum separation standards (currently 5 Nm horizontally and 1000 ft vertically) are still satisfied. Moreover, it is desirable that proposed new trajectories deviate as little as possible from RBTs. Several methods have been tested to find an optimal solution to address this problem including genetic algorithm[1] and navigation function based approach[2]. The first approach can not guarantee a feasible (conflict-free) solution for a given time computing. The second one does not take into account the constraints imposed by ATM, such as bounded velocity
ON THE COTANGENT BUNDLE AND UNIT COTANGENT BUNDLE WITH A GENERALIZED CHEEGER-GROMOLL METRIC
In this paper, we consider a generalized Cheeger-Gromoll metric on a cotangent bundle over a Riemannian manifold, which is obtained by rescaling the vertical part of the Cheeger-Gromoll metric by a positive dierentiable function. Firstly, we investigate the curvature properties on the cotangent bundle with the generalized Cheeger-Gromoll metric. Secondly, we introduce the unit cotangent bundle equipped with this metric, where we present the formulas of the Levi-Civita connection and also all formulas of the Riemannian curvature tensors of this metric. Finally, we study the geodesics on the unit cotangent bundle with respect to this metric
Comparison of Two Methods of Predicting 305-day Milk Yield for Genetic Evaluation to Design a Tunisian Holstein Reference Population
Various standardized milk yield prediction methods have been developed and used. The objective of this study was to compare two methods for the estimation of 305-day milk yield inthe Holstein breed, in terms of breeding values and their accuracy. Genetic evaluations of milk yield were compared using%253A 1) adjusted total lactation yield for days in milk, month, and age at calving (adjusted TY305) or 2) adjusted305-day milk yieldestimated by fitting test-day(TD) records to the Wood model(adjusted WY305).The method with better ability to predict standardized milk yield was used to identify a Tunisian cow reference population toward genomic evaluation of milk trait. Three datasets were used. The first data contains 380709 TD records corresponding to 34281 three first lactations of 20758 cows collected between 2008 and 2018 in 33 herds. The second dataset contains 11175 total first three lactation yields recorded between 2012 and 2017 from 6251 cows belonging to 33 herds.The third data is a pedigree file of 27487 males and females. The predictive ability of the two methods was assessed by Spearmans rank correlation between predicted breeding values for 305-day milk yield (PBV305) from the full dataset and reduced dataset in which the records from the last calving year were masked. The two methods were compared in terms of rank correlation between PBV305 and the percentage of selected animals in common when different selection intensities were applied based on PBV305.The average gain in accuracy was calculated and a Tunisian reference population was identified. The results showed that heritability estimates were 0.11 (plusmn%253B0.02) and 0.13 (plusmn%253B0.01) for adjusted WY305 and TY305, respectively. The highest correlation for PBVs between full data and reduced data was achieved in TY305 dataset. Rank correlations between PBV305 estimated for adjusted WY305 and TY305 were 0.67. The percentage of animals selected in common was 11%25 or 21%25, respectively, when 1 or 5%25 of cows were chosen as future dams of bulls, according to PBVs. An average gain in accuracy of 15%25 was observed for cows when using adjusted TY305 to estimate PBVs for milk yield trait. The obtained results showed that adjustments applied to the total milk yield records could be appropriate for 305-day milk yield prediction and genetic evaluation of milk production in the Tunisian Holstein population. Based on two main designs (extreme yield and top accuracy), a total of 1000 cows were selected to form the Tunisian female reference population using adjusted TY305 records
Role of the alcoholic father image in the construction of the adolescent’s identity Clinical case study
هدفت الدراسة الحالية إلى التعرف على طبيعة الدور الذي تلعبه صورة الأب المدمن على الكحول في بناء هوية الفتاة المراهقة.
أوضحت نتائج الدراسة أنّ صورة الأب المدمن على الكحول تؤثر بشكل سلبي في بناء هوية الفتاة المراهقة، أي أنّ فشل الصورة النفسية الرمزية للأب ينجم عنها قلق الأنا واضطراب البنية النفسية للمراهقة.The present study aims to understand how the image of the alcoholic father influences the construction of the adolescent identity.
The results of the study showed that the image of the alcoholic father negatively influences the construction of the adolescent identity, which means that the failure of the psychological symbolic image of the father leads to ego anxiety, and a disturbance in the psychic structure of the adolescent
Résolution de conflit dans le trafic aérien via l'algorithme de la propagation de la lumière
National audienceL'analyse de la croissance du trafic aérien prévoit un doublement du nombre de vols dans les vingt prochaines années. Le système de gestion du trafic aérien (ATM) devra augmenter en conséquence la capacité de l'espace aérien tout en assurant un niveau de sécurité au moins équivalent à ce qui existe actuellement. Le projet européen SESAR a été initié afin de proposer des solutions à ce problème. Il s'appuie sur un nouveau concept de contrôle du trafic, appelé trajectoire 4D, et qui consiste à garantir les positions des avions à un temps donné. Pour chaque vol, une trajectoire de référence, appelée RBT, est demandée par la compagnie opératrice. Au cours du vol, il peut apparaître des situations dites de conflit, dans lesquelles un rapprochement dangereux des aéronefs a lieu. Dans ce cas, il est nécessaire de modifier une ou plusieurs trajectoires afin de s'assurer que les normes de séparation minimales entre avions (actuellement 5 Nm en horizontal et de 1000 ft en vertical) soient respectées. Il est souhaitable de plus que les nouvelles trajectoires proposées soient aussi proches que possible des RBT. Il existe actuellement deux classes de méthodes permettant cette opération : les algorithmes génétiques [1] et les fonctions de navigation [2]. Chacune n'apporte qu'une réponse partielle au problème : les algorithmes génétiques permettent l'obtention de façon asymptotique de la solution optimale, mais ne garantissent pas l'obtention d'une solution admissible en un temps borné ; les fonctions de navigations quant à elles assurent l'absence de conflit mais génèrent des trajectoires qui ne sont pas forcément volables par un aéronef. L'objectif de la méthode que nous proposons, basée sur une analogie avec l'optique, est de trouver pour chaque avion une trajectoire optimale 4D évitant les conflits et minimisant un critère basé sur une métrique locale
Aircraft Trajectory Planning Under Uncertainty by Light Propagation
AbstractIn the SESAR framework (Single European Sky ATM Research), the need to increase the air traffic capacity motivated the 4D (space + time) aircraft trajectory planning. This paper deals with an important Air Traffic Management (ATM) problem that consists in generating sets of 4D conflict-free trajectories (the tactical planning problem). The Light Propagation Algorithm (LPA) was introduced in [1] to deal with this problem. LPA has recently been shown to manage successfully a full day of traffic over the French airspace, removing all conflicts while satisfying ATM constraints.In this paper, we adapt the LPA to take into account uncertainties in trajectory prediction. We introduce and test a new algorithm called u/LPA (LPA under uncertainty) on the same day of traffic. For some situations, uncertainties reduce so much the search space that the standard algorithm cannot guarantee conflict free situation. As a consequence, one must include some time constraints for few trajectories (so-called RTA points: Real Time of Arrival constraints) in order to remove the remaining conflicts. The goal of RTA points is to impose an aircraft to be at a specified position at some given time. This results into a new optimization formulation of the tactical trajectory planning problem involving the decision as to where/when RTA points should be imposed. In order to solve this new problem, here we are content with a simple heuristic that yields encouraging results
Academic Counseling and its role to achieving quality higher education
تهدف هذه الدراسة إلى بيان دور الإرشاد الأكاديمي في تحسين جودة التعليم الجامعي، باعتبار أن الإرشاد الأكاديمي من الممارسات المهمة في التعليم التي تقوم عليها مؤسسات التعليم الجامعي، باعتباره ضرورة ملحة فرضتها التغيرات المتلاحقة والمتسارعة في التعليم بشكل عام وفي التعليم العالي بصورة خاص إذ يمثل اهم المرتكزات الرئيسية التي تقوم عليها مؤسسات التعليم العالي، وتوليها أهمية بالغة ويهتم بدراسته العديد من الباحثين والمتخصصين، حيث يقوم بتنمية المورد البشري وبناء قدرات الطالب الجامعي المعرفية الثقافية النفسية والمهاراتية في كافة التخصصات بهدف تحسين جودة التعليم الجامعي.This study aims at demonstrating the role of academic guidance in improving the quality of university education, since academic guidance is an important practice in education on which university education institutions are based. As an urgent necessity imposed by successive and accelerating changes in education in general and in higher education in particular, as it represents the main foundations on which higher education institutions are based, and attaches great importance to its study by many researchers and specialists, It develops the human resource and builds the psychological and professional cultural knowledge of the university student in all disciplines with a view to improving the quality of university education
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