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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 Dec 01 2011
Journal Name
Journal Of Engineering
SIMULATION MODEL FOR THE ASSESSMENT OF DIRECT AND INDIRECT GEOREFERENCING TECHNIQUES IN ANALYTICAL PHOTOGRAMMETRY
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This paper compares between the direct and indirect georeferencing techniques in Photogrammetry bases on a simulation model. A flight plan is designed which consists of three strips with nine overlapped images for each strip by a (Canon 500D) digital camera with a resolution of 15 Mega Pixels.

 

The triangulation computations are carried out by using (ERDAS LPS) software, and the direct measurements are taken directly on the simulated model to substitute using GPS/INS in real case. Two computational tests have been implemented to evaluate the positional accuracy for the whole model and the Root Mean Square Error (RMSE) relating to (30) check points show that th

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Publication Date
Tue May 16 2023
Journal Name
Political Sciences Journal
The Dens of Extremism and Terrorism in Syrian Camps (Al-Hol as a model)
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After the defeat of the military terrorist organization "ISIS" and the fall of the throne of its alleged state in the Iraqi city of Nineveh, in Syrian Baghouz, and the end of its control over the land, the Syrian camps, especially "Al-Hol" camp, emerge as an incubator for the ideology of the terrorist organization "ISIS" and a vital base for its consolidation and dissemination, which includes (68,000- 73,000) people. During the years following the military defeat of (ISIS), the camp witnesses the spread of extremist ideas widely at the hands of its residents, including the families of the organizations dead's, extremist detainees, and those who deal with it, taking advantage of the deterioration of the environmental, se

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Publication Date
Fri Sep 06 2024
Journal Name
Brazilian Journal Of Physics
Effect of the Fear Factor and Prey Refuge in an Asymmetric Predator–Prey Model
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This study investigates the influence of fear, refuge, and migration in a predator–prey model, where the interactions between the species follow an asymmetric function response. In contrast to some other findings, we propose that prey develop an anti-predator response in response to a concentration of predators, which in turn increases the fear factor of the predators. The conditions under which all ecologically meaningful equilibrium points exist are discussed in detail. The local and global dynamics of the model are determined at all equilibrium points. The model admits several interesting results by changing the rate of fear of predators and predator aggregate sensitivity. Numerical simulations have been performed to verify our theoret

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Publication Date
Sun Mar 12 2023
Journal Name
المجلة الدولية للتنمية في العلوم الاجتماعية والإنسانية
the Ottoman Empire in the Nineteenth Century (Iraq as a Model)the Ottoman Empire in the Nineteenth Century (Iraq as a Model)
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One of the most important features of American foreign activity during the second half of the 19th century was the encouragement of sending Protestant missionary missions to all countries around the world. The mission of these missions was facilitated by the weakened state of the Ottoman Empire, the increasing influence of European countries, and their interference in its internal affairs. Despite the Ottoman efforts to counter the activities of these missions, the American missionary missions adopted a well-planned strategy that suited the conditions of the region, aimed at achieving their goals through direct and indirect methods, including intervention in the field of education. These missions gave great importance to educational aspects

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Publication Date
Wed Dec 01 2021
Journal Name
International Journal Bioautomation
Model for Prediction of the Weight and Height Measurements of Patients with Disabilities for Diagnosis and Therapy
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Background: Accurate measurement of a patient’s height and weight is an essential part of diagnosis and therapy, but there is some controversy as to how to calculate the height and weight of patients with disabilities. Objective: This study aims to use anthropometric measurements (arm span, length of leg, chest circumference, and waist circumference) to find a model (alternatives) that can allow the calculation of the height and the body weight of patients with disabilities. Additionally, a model for the prediction of weight and height measurements of patients with disabilities was established. Method: Four hander patients aged 20-80 years were enrolled in this study and divided into two groups, 210 (52.5%) male and 190 (47.5%) fe

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Scopus (9)
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Publication Date
Wed Oct 09 2019
Journal Name
Journal Of The College Of Education For Women
Naber and toning in the modern Arab poetry Mahmoud Darwish, a model
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Naber and toning in the modern Arab poetry Mahmoud Darwish, a model

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Publication Date
Mon Jan 28 2019
Journal Name
Journal Of The College Of Education For Women
Apply the gravity model for trips between Najaf center and its settlements
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The study showed flow rates and the interaction between the settlements served by applying the model of gravity theory to measure depending on the number of the population between city Najaf and the rest of the other settlements served and using three functions of disability, time and cost, as recorded an increase in the interaction index with some settlements like them Kufa, Abbasid and Manathira, while the indicator contrast was in other settlements, either when the application of the gravity model depending on trips and socio-economic characteristics accuracy rate was more pronounced.

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Publication Date
Fri Jul 23 2021
Journal Name
International Journal Of Nonlinear Analysis And Applications
On the dynamical behavior of an eco-epidemiological model
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The aim of this article is to study the dynamical behavior of an eco-epidemiological model. A prey-predator model comprising infectious disease in prey species and stage structure in predator species is suggested and studied. Presumed that the prey species growing logistically in the absence of predator and the ferocity process happened by Lotka-Volterra functional response. The existence, uniqueness, and boundedness of the solution of the model are investigated. The stability constraints of all equilibrium points are determined. The constraints of persistence of the model are established. The local bifurcation near every equilibrium point is analyzed. The global dynamics of the model are investigated numerically and confronted with the obt

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Publication Date
Sun Jun 02 2019
Journal Name
Baghdad Science Journal
Estimating the Reliability Function of (2+1) Cascade Model
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This paper discusses reliability R of the (2+1) Cascade model of inverse Weibull distribution. Reliability is to be found when strength-stress distributed is inverse Weibull random variables with unknown scale parameter and known shape parameter. Six estimation methods (Maximum likelihood, Moment, Least Square, Weighted Least Square, Regression and Percentile) are used to estimate reliability. There is a comparison between six different estimation methods by the simulation study by MATLAB 2016, using two statistical criteria Mean square error and Mean Absolute Percentage Error, where it is found that best estimator between the six estimators is Maximum likelihood estimation method.

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Publication Date
Thu Jan 12 2023
Journal Name
Mathematics
Dynamical Behavior of a Cancer Growth Model with Chemotherapy and Boosting of the Immune System
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In this study, we set up and analyze a cancer growth model that integrates a chemotherapy drug with the impact of vitamins in boosting and strengthening the immune system. The aim of this study is to determine the minimal amount of treatment required to eliminate cancer, which will help to reduce harm to patients. It is assumed that vitamins come from organic foods and beverages. The chemotherapy drug is added to delay and eliminate tumor cell growth and division. To that end, we suggest the tumor-immune model, composed of the interaction of tumor and immune cells, which is composed of two ordinary differential equations. The model’s fundamental mathematical properties, such as positivity, boundedness, and equilibrium existence, are exami

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