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The dynamics of nutrient, toxic phytoplankton, nontoxic phytoplankton and zooplankton model
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<p>The objective of this paper is to study the dynamical behavior of an aquatic food web system. A mathematical model that includes nutrients, phytoplankton and zooplankton is proposed and analyzed. It is assumed that, the phytoplankton divided into two compartments namely toxic phytoplankton which produces a toxic substance as a defensive strategy against predation by zooplankton, and a nontoxic phytoplankton. All the feeding processes in this food web are formulating according to the Lotka-Volterra functional response. This model is represented mathematically by the set of nonlinear differential equations. The existence, uniqueness and boundedness of the solution of this model are investigated. The local and global stability conditions of all possible equilibrium points are established. The occurrence of local bifurcation and Hopf bifurcation are investigated. Finally, numerical simulation is used to study the global dynamics of this model.</p>

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Publication Date
Thu Nov 01 2012
Journal Name
Iraqi Journal Of Science
THE EVOLUTION OF PLANETARY NEBULAE(PN) AND FADING TIME ACCORDING TO SYNTHETIC MODEL
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Abstract Planetary nebulae (PN) represents the short phase in the life of stars with masses (0.89-7) M☉. Several physical processes taking place during the red giant phase of low and intermediates-mass stars. These processes include :1) The regular (early ) wind and the envelope ejection, 2) The thermal pulses during Asymptotic Giant Branch (AGB ) phase. In this paper it is briefly discussed how such processes affect the mass range of Planetary Nebulae(PN) nuclei(core) and their evolution, and the PN life time, and fading time for the masses which adopted. The Synthetic model is adopted. The envelope mass of star (MeN ) and transition time (ttr) calculated respectively for the parameter (MeR =1.5,2, 3×10-3 M☉). Another time scale is o

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Publication Date
Mon Jan 02 2017
Journal Name
Journal Of Educational And Psychological Researches
Toward a theoretical model of the terrorist personality and differentiation from psychopathic personality
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The current theoretical research targeted to construct a model of terrorist personality and its differentiation from psychopathic personality . Several assumptions or theories of perspectives of psychopathic personality have been compared with the terrorist personality studies that concerned . The suggested theoretical  model is interrupting the terrorist personality . The conclusions , discussions are mentioned. Finally, recommendation is suggested .

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Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
Educational values in the Quran: Surat Luqman and AL- Hujurat model
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The paper has been summarized into the following:
Chapter one: the researcher deals with the problem of the paper, the most important points and the terminology. Chapter two: the researcher deals Surat Luqman from the Aya 12-19 , (the demonstration, the explanations, the values ). In chapter three the researcher deals with Surat AL-Hujurat from Aya 6-12, (the demonstration, the explanations, the values ). Chapter four include (the educational properties for individual and society, the educational applications, and the most important indicators in the texts). Chapter five include the results , the conclusions and the recommendations. One of the basic results that the Quran is a complete educational curriculum, and the texts of Surat Lu

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Publication Date
Tue Mar 26 2019
Journal Name
International Journal Of Mathematics And Mathematical Sciences
Stability and Bifurcation of a Prey-Predator-Scavenger Model in the Existence of Toxicant and Harvesting
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In this paper a prey-predator-scavenger food web model is proposed and studied. It is assumed that the model considered the effect of harvesting and all the species are infected by some toxicants released by some other species. The stability analysis of all possible equilibrium points is discussed. The persistence conditions of the system are established. The occurrence of local bifurcation around the equilibrium points is investigated. Numerical simulation is used and the obtained solution curves are drawn to illustrate the results of the model. Finally, the nonexistence of periodic dynamics is discussed analytically as well as numerically.

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Publication Date
Mon Feb 01 2021
Journal Name
Journal Of Physics: Conference Series
Bayesian Computational Methods of the Logistic Regression Model
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Abstract<p>In this paper, we will discuss the performance of Bayesian computational approaches for estimating the parameters of a Logistic Regression model. Markov Chain Monte Carlo (MCMC) algorithms was the base estimation procedure. We present two algorithms: Random Walk Metropolis (RWM) and Hamiltonian Monte Carlo (HMC). We also applied these approaches to a real data set.</p>
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Publication Date
Mon Jan 01 2024
Journal Name
Aip Conference Proceedings
The dynamical behavior of AIDS and HCV infection model with two modes of transmission
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The aim of this paper is to describe an epidemic model when two SI-Type of diseases are transmitted vertically as well as horizontally through one population. The population contains two subclasses: susceptible and infectious, while the infectious are divided into three subgroups: Those infected by AIDS disease, HCV disease, and by both diseases. A nonlinear mathematical model for AIDS and HCV diseases is Suggested and analyzed. Both local and global stability for each feasible equilibrium point are determined theoretically by using the stability theory of differential equations, Routh-Hurwitz and Gershgorin theorem. Moreover, the numerical simulation was carried out on the model parameters in order to determine their impact on the disease

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Publication Date
Thu Oct 31 2024
Journal Name
Mathematical Modelling Of Engineering Problems
Investigating the Effects of Canard Dihedral Angle on the Wing Span Loading in a Forward-Swept Wing Aircraft at Transonic Speeds at Steady State Conditions Using Computational Fluid Dynamics
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Forward-swept wings were researched and introduced to improve maneuverability, control, and fuel efficiency while reducing drag and they are often used alongside canards, to further enhance their characteristics. In this research, the effects of canard dihedral angles on the wing loading of a forward-swept wing in transonic flow conditions were studied, as the wing loading provides a measure of wing’s efficiency (lift/drag). A generic aircraft model from literatures was selected, simulated, and compared to, using CFD software ANSYS/Fluent where the flow equations were solved to calculate the aerodynamic characteristics. The research was carried at two different Mach numbers, 0.6 and 0.9, for five different canard dihedral angles which tra

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Publication Date
Wed Jan 01 2020
Journal Name
Proceedings Of The 2020 2nd International Conference On Sustainable Manufacturing, Materials And Technologies
The impact of toxicant on the food chain ecological model
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Publication Date
Wed Sep 29 2021
Journal Name
College Of Islamic Sciences
The provisions of the epidemic in jurisprudence and its principles The (Covid-19) epidemic is a model
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Abstract

Epidemics that afflict humankind are descending renewed, plaguing them in the place and time they spread.

- The epidemic affects individuals and the movement of societies, and its treatment requires dealing with it according to Sharia, taking into account the current data and developments.

- Integrative jurisprudence: it is intended to know the practical legal rulings deduced from the combination of evidence of two or more sciences related to one topic related to it, and among these calamities is the Corona Covid-19 pandemic.

 - It is permissible to use sterile materials that contain a percentage of alcohol in sterilizing hands and fogging places, including mosques.

T

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Publication Date
Mon May 23 2022
Journal Name
The International Journal Of Artificial Organs
Quantitative analysis and control of the torque profile of the upper limb using a kinetic model and motion measurements
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This paper investigates a new approach to the rapid control of an upper limb exoskeleton actuator. We used a mathematical model and motion measurements of a human arm to estimate joint torque as a means to control the exoskeleton’s actuator. The proposed arm model is based on a two-pendulum configuration and is used to obtain instantaneous joint torques which are then passed into control law to regulate the actuator torque. Nine subjects volunteered to take part in the experimental protocol, in which inertial measurement units (IMUs) and a digital goniometer were used to measure and estimate the torque profiles. To validate the control law, a Simscape model was developed to simulate the arm model and control law in which measurem

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