<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>
This research aims toknow the learning styles according to the model of Felder and Silverman and its relationship to effectively self- perceived mathematicalamong students of the Faculty of Education Pure Sciences - Ibn al-Haytham. By answering the following questions: 1. What are the preferred methods of learning among students in the mathematics department according to the model Felder and Silverman? 2. What is the mathematicalself-perceived levelof the students at the Department of Mathematics effectiveness level? 3. What is the relationship between learning styles according to the Felder model and Silverman and the effectiveness of mathematical self-perceived of the students of the Department of Mathematics? The research sample consiste
... Show MoreThe main objective of this study is to measure the Impact of global financial crisis on some indicators of the Saudi Arabia's economy using the Mendel-Fleming model, the importance of the study applied by focusing on the theme of general equilibrium in the face of fluctuations in the global economy. Study used a descriptive approach and the methodology of econometrics to construct the model. Study used Eviews Program for data analysis. The Data was collected from the Saudi Arabian Monetary Agency, for the period (1997-2014).Stationery of the variables was checked by Augmented Dickey-Fuller (ADF) and Phillips Perron (PP) unit roots tests. And also the co-integration
... Show MoreThe aim of the research is to measure the efficiency of the companies in the industrial sector listed in the Iraqi Stock Exchange , by directing these companies to their resources (inputs) towards achieving the greatest possible returns (outputs) or reduce those resources while maintaining the level of returns to achieve the efficiency of these companies, therefore, in order to achieve the objectives of the research, it was used (Demerjian.et.al) model to measure the efficiency of companies and the factors influencing them. The researchers had got a number of conclusions , in which the most important of them is that 66.6% of the companies in the research sample do not possess relatively high efficiency and that the combined factors (the nat
... Show MoreThe aim of the research is to measure the efficiency of the companies in the industrial sector listed in the Iraqi Stock Exchange , by directing these companies to their resources (inputs) towards achieving the greatest possible returns (outputs) or reduce those resources while maintaining the level of returns to achieve the efficiency of these companies, therefore, in order to achieve the objectives of the research, it was used (Demerjian.et.al) model to measure the efficiency of companies and the factors influencing them. The researchers had got a number of conclusions , in which the most important of them is that 66.6% of the companies in the research sample do no
... Show MoreThe research seeks to study the subject (Media separation: the Relationship of Arab Immigrants with the Media of the Countries of Diaspora/ Sweden as a model). Where this phenomenon, "problem" has not been subjected to an in-depth study to find out the causes of this media separation and its repercussions on the immigrant, whether in the problem of integration, or his opportunity to work, or adapt to live in the new society.
Separation is a kind of word that is rarely used in Arabic media studies, relevant, sometimes, to the meaning of “refraining from watching TV or listening to the radio or reading newspapers”. Sometimes, it means “not tuning to or using any form of media like radios or newspapers to be updated about what
... Show Moreيؤدي عرض معلومات مضللة او محرفة ضمن القوائم المالية والتي تعد أهم مصادر المعلومات الموثوقة التي يُعول عليها لاتخاذ القرارات السليمة الى عدم قدرتها على عكس نتيجة النشاط والمركز المالي لها او اعمال الوحدة الاقتصادية لتلك الفترات الزمنية بصورة صادقة وعادلة نتيجة لنوعية المعلومات المفصح عنها في القوائم المالية لذلك زاد الاهتمام بتطوير الممارسات المحاسبية لتتضمن افصاحات كافية بغرض اعطائهم صورة صادقة وعادلة
... Show MoreThe current research aims to investigate the effect of a specimen of Daniel in the acquisition of concepts for the Arabic language curricula material to the students of the third phase of the Faculty of Basic Education Department of Arabic Language. The sample consists of (93) applications and a student of (47) students in the Division (A), which represents the experimental group which studied the use of a specimen of Daniel, and (46) students in the Division (B), which represents the control group, which studied the traditional way. The subject of unified two groups, which subjects the Arabic language curricula which includes six chapters.
The duration of the experiment is a full semester. The researchers also prepared a tool for mea
(Social values) are of great importance in the lives of nations and peoples as they are the frame of reference that governs the relations of members of society to each other and regulates their life affairs.
And the Prophet of Islam (may God’s prayers and peace be upon him) has told about a group of (social values) such as: spreading peace, feeding food, being fair in dealing with others, and clarifying what a Muslim should have towards his Muslim brother from the safety of the chest and refraining from harming him with the tongue and hand, and so on. Ethics and behaviors that are directly and closely related to (social values).
The best book that abounds with these (social valu
... Show MoreThis research aims at identifying the communicative habits and content reflections on the communication process, especially the young audience which is one of the main group for whom the announcements are made. Because young people face life with passion and aspiration making them respond to each effect used by the media in the design of the advertising using all the effective techniques, attractive methods for young children like depending on drama, technical tricks, music and logos easily to be remembered and responded to the desires of the young in their entertainment. This research also aims at identifying the impact of the internet as a channel of commercial advertising on the purchasing behavior of young people at the universities
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