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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
Sat Oct 12 2024
Journal Name
Biorxiv
The thermotolerant Arabian killifish,<i>Aphanius dispar</i>, as a novel infection model for human fungal pathogens
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Abstract<p><italic>Candida albicans</italic>: a fungal pathogen, can cause superficial and fatal infections in humans. An important virulence factor in<italic>C. albicans</italic>dissemination is the transformation from yeast to an invasive hyphal form, which is favoured at human body temperature. Zebrafish, a useful model for studying<italic>C. albicans</italic>infections, cannot survive at 37°C. Arabian killifish,<italic>Aphanius dispar</italic>, an emerging teleost model can tolerate temperatures up to 40 °C for up to 12 days (independent feeding time) allowing for longer analysis compared to zebrafish. This study introduces<italic>A. dispar</italic>as a th</p> ... Show More
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Publication Date
Wed Sep 15 2021
Journal Name
Al-academy
Applying the substance-field model mechanism to problem solving in industrial product design: محمد علي حسين القيسي
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  Problem solving methods and mechanisms contribute to facilitating human life by providing tools to solve simple and complex daily problems. These mechanisms have been essential tools for professional designers and design students in solving design problems.
This research dealt with one of those mechanisms, which is the (the substance-field model model), as it has been mentioning that this mechanism is characterized by the difficulty of its application, which formed the main research problem. In home gardens (the sub-problem of research), an analysis of this problem was applied and then a solution was found to address it. The researcher used the 3dsmax program to implement the proposed design.
The most important research res

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Publication Date
Tue Dec 22 2020
Journal Name
Collaboration And Integration In Construction, Engineering, Management And Technology
A Hybrid Conceptual Model for BIM Adoption in Facilities Management: A Descriptive Analysis for the Collected Data
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Publication Date
Mon Oct 01 2018
Journal Name
Al–bahith Al–a'alami
President Trump›s media discourse in the US election Study in electronic news sites - CNN ARABIC Model
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The letter is defined as a message directed by the sender to another party, the future. The aim is to convey, clarify or explain a particular point or subject, and in the form of direct oral communication through speech that contains a set of words and words, The future can discuss the sender directly to exchange ideas with each other, or it may be written and in this case does not require direct interaction between the matchmaker and the recipient. As a result of the different sources and topics of the discourse, and the different types of categories addressed to the speech, and the number, it has been divided into several types.
And schools of discourse analysis emerged in the early eighties of the last century and has spread and ha

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Publication Date
Tue Jan 01 2019
Journal Name
Australian Journal Of Mathematical Analysis And Applications
Formulation of approximate mathematical model for incoming water to some dams on Tigris and Euphrates Rivers using spline function
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n this paper, we formulate three mathematical models using spline functions, such as linear, quadratic and cubic functions to approximate the mathematical model for incoming water to some dams. We will implement this model on dams of both rivers; dams on the Tigris are Mosul and Amara while dams on the Euphrates are Hadetha and Al-Hindya.

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Scopus
Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
ESTIMATION OF COEFFICIENTS AND SCALE PARAMETER FOR LINEAR (TYPE 1) EXTREME VALUE REGRESSION MODEL FOR LARGEST VALUES WITH APPLICATIONS
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In this paper we estimate the coefficients and scale parameter in linear regression model depending on the residuals are of type 1 of extreme  value distribution for the largest values . This can be regard as an improvement for the studies with the smallest values . We study two estimation methods ( OLS  & MLE ) where we resort to Newton – Raphson (NR) and Fisher Scoring methods to get MLE estimate because the difficulty of using the usual approach with MLE . The relative efficiency criterion is considered beside to the statistical inference procedures for the extreme value regression model of type 1 for largest values . Confidence interval , hypothesis testing for both scale parameter and regression coefficients

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Publication Date
Sun Oct 01 2023
Journal Name
Applied Sciences
Multiobjective Optimization of Stereolithography for Dental Bridge Based on a Simple Shape Model Using Taguchi and Response Surface Methods
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Stereolithography (SLA) has become an essential photocuring 3D printing process for producing parts of complex shapes from photosensitive resin exposed to UV light. The selection of the best printing parameters for good accuracy and surface quality can be further complicated by the geometric complexity of the models. This work introduces multiobjective optimization of SLA printing of 3D dental bridges based on simple CAD objects. The effect of the best combination of a low-cost resin 3D printer’s machine parameter settings, namely normal exposure time, bottom exposure time and bottom layers for less dimensional deviation and surface roughness, was studied. A multiobjective optimization method was utilized, combining the Taguchi me

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Publication Date
Tue May 07 2019
Journal Name
Proteomics
Proteomic Analysis of Stromal and Epithelial Cell Communications in Human Endometrial Cancer Using a Unique 3D Co‐Culture Model
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Abstract<p>Epithelial and stromal communications are essential for normal uterine functions and their dysregulation contributes to the pathogenesis of many diseases including infertility, endometriosis, and cancer. Although many studies have highlighted the advantages of culturing cells in 3D compared to the conventional 2D culture system, one of the major limitations of these systems is the lack of incorporation of cells from non‐epithelial lineages. In an effort to develop a culture system incorporating both stromal and epithelial cells, 3D endometrial cancer spheroids are developed by co‐culturing endometrial stromal cells with cancerous epithelial cells. The spheroids developed by this method are phenot</p> ... Show More
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Publication Date
Sun Jan 01 2012
Journal Name
مجلة واسط للعلوم والطب
Study of nuclear characters to some 164, 166, 168 68 Er isotopes by using the interacting boson model IBM-1
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The aim of this study is to show the concepts of nuclear shape and the geometrical picture to the even-even nuclei of 164,166,168E isotopes in the context of the Interacting boson Model IBM-1. The energy spectra were calculated and the effective charge values (eB) of the electromagnetic transition strength were obtained and used to calculate the B(E2) values of the electromagnetic transitions and the quadrupole moment Q of 2+ -states. The Hamiltonian parameters were calculated by taking in account the properties of these nuclei. Comparison were made with the available experimental data and included in tables. The geometrical picture of these nuclei were looked at by calculating the deformation which were represented by the potentia

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Publication Date
Fri Oct 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
Institutional Performance Assessment using a model of the European Foundation for Quality Management (EFQM) A case study at an organization
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The study aims to use the European Excellence Model (EFQM) in assessing the institutional performance of the National Center for Administrative Development and Information Technology in order to determine the gap between the actual reality of the performance of the Center and the standards adopted in the model, in order to know the extent to which the Center seeks to achieve excellence in performance to improve the level of services provided and the adoption of methods Modern and contemporary management in the evaluation of its institutional performance.

The problem of the study was the absence of an institutional performance evaluation system at the centre whereby weaknesses (areas of improvement) and st

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