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On the Stability of Four Dimensional Lotka-Volterra Prey-Predator System
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The aim of this work is to study a modified version of the four-dimensional Lotka-Volterra model. In this model, all of the four species grow logistically. This model has at most sixteen possible equilibrium points. Five of them always exist without any restriction on the parameters of the model, while the existence of the other points is subject to the fulfillment of some necessary and sufficient conditions. Eight of the points of equilibrium are unstable and the rest are locally asymptotically stable under certain conditions, In addition, a basin of attraction found for each point that can be asymptotically locally stable. Conditions are provided to ensure that all solutions are bounded. Finally, numerical simulations are given to verify and support the obtained theoretical results.

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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Comparing the Sequential Nonlinear least squared Method and Sequential robust M method to estimate the parameters of Two Dimensional sinusoidal signal model:
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Estimation of the unknown parameters in 2-D sinusoidal signal model can be considered as important and difficult problem. Due to the difficulty to find estimate of all the parameters of this type of models at the same time, we propose sequential non-liner least squares method and sequential robust  M method after their development through the use of sequential  approach in the estimate suggested by Prasad et al to estimate unknown frequencies and amplitudes for the 2-D sinusoidal compounds but depending on Downhill Simplex Algorithm in solving non-linear equations for the purpose of obtaining non-linear parameters estimation which represents frequencies and then use of least squares formula to estimate

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Publication Date
Thu Apr 27 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Effect of Carbimazol-induced Hypothyroidism on Male Rat Reproductive System
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The present study is undertaken to evaluate the effects of hypothyroidism induced by carbimazol in male rat reproductive system. Rats were treated with carbimazol (80 and 160 mg/kg body weight) daily for two, four, six, and eight weeks, while control rats were given distilled water orally. The results of these experiments are: 1-Treatment with carbimazol produced increase in body weight of treated animals. This increase was not statistically significant even at high concentrations. 2-Decrease in testicular weight  was observed during all administration points. This decrease was aggravated proportional to duration and dose (p≤0.001). 3-Results of most intervals showed significant decrease in epididymal-head weight, while no sig

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Publication Date
Wed May 17 2023
Journal Name
Journal Of Engineering
Design of a Differential Chaotic on-off keying communication system
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Among the available chaotic modulation schemes, differential chaos shift keying (DSCK) offers the perfect noise performance. The power consumption of DCSK is high since it sends chaotic signal in both of 1 and 0 transmission, so it does not represent the optimal choice for some applications like indoor wireless sensing where power consumption is a critical issue. In this paper a novel noncoherent chaotic communication scheme called differential chaos on-off keying (DCOOK) is proposed as a solution of this problem. With the proposed scheme, the DCOOK signal have a structure similar to chaos on-off keying (COOK) scheme with improved performance in noisy and multipath channels by introducing the concept of differential coherency used in DCS

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Publication Date
Thu Aug 01 2024
Journal Name
Journal Of King Saud University - Engineering Sciences
Impact of long-term depletion on horizontal wellbore stability in tight reservoirs-including changes in petrophysical and geomechanical properties
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Publication Date
Mon Nov 01 2021
Journal Name
Journal Of Engineering
Stability Improvement of The Iraqi Super Grid (400kV) using High Voltage Direct Current (HVDC) Transmission
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This research analyzes the level of the short circuit effect of the Iraqi super network and decides the suitable location for the High Voltage Direct Current (HVDC) connections in order to obtain the best short circuit reduction of the total currents of the buses in the network. The proposed method depends on choosing the transmission lines for Alternating current (AC) system that suffers from high Short Circuit Levels (SCLs) in order to reduce its impact on the transmission system and on the lines adjacent to it and this after replacing the alternating current (AC) line by direct current (DC) line. In this paper, Power System Simulator for Engineering (PSS/E) is used to model two types of HVDC lines in an effective regi

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Publication Date
Fri Oct 07 2022
Journal Name
Himalayan Economics And Business Management
Analyzing and Measuring the Relationship between Monetary Policy and Monetary Stability in the Iraqi Economy for the Period 1990-2020
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Monetary policy occupies a prominent role in achieving monetary stability by adjusting the growth rates of the number of available means of payment in line with changes in the size of the gross domestic product in the country and expressed by the monetary stability coefficient agreed upon by the International Monetary Fund, a term that hides the fact that there is a rate of change in the volume of commodity or real production which expresses the levels of aggregate supply in the economy, which corresponds to the quantities of cash in circulation, which represent a net purchasing power and stimulate aggregate demand, which completes the picture of the existence of the market mechanism, expressed by the monetary or economic stability

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Publication Date
Fri Jan 26 2024
Journal Name
Iraqi Journal Of Science
Study of rock slope stability of formation outcrops in Hamrin Anticline /NE Tikrit.
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This Study aims to engineering geological evaluation of Fatha and Injana Formations in northern Hamrin anticline throughout geological and engineering geological Survey including Preparing engineering geological map (Scale1:90000) and Studying rock Slopes Stability in (6) Stations ,representing all types of failures (taken place and possible).General Survey for rock Slopes included Classification and engineering description according to [1], [2]. The slopes in the area are Classified based on the direction of the Strike Slopes and Strike of beds into Parallel, Oblique Lateral and orthogonal Slopes according to [3].Classification and the Slope Types are Concordant Slope and discordant Slope . The rocks in the area consists of two engineer

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Publication Date
Fri Mar 31 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Formulation, Stability and Bioequivalency Study of Prepared Salbutamol Sulphate Nebules.
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Salbutamol sulphate nebules is considered as the most rapid effective route of
administration for treatment of acute attacks of asthma .
This study was carried out to formulate a stable formula of salbutamol nebules
containing 0.1% (2.5mg / 2.5ml) of the active ingredient in a buffered solution .
Stability study in different buffers at pH 3 showed that the longest shelf life was
equal to 3.5 years for formula F .In addition the bioequivalency of this formula
incomparison to ventolin® nebules was measured and it was equal to (± 5.2) %.
Also it was found that there was no significant difference between the formula
and ventolin® nebules regarding their pharmacokinetic parameters which include
elimination

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Stability constants of iron(II) supported and lead(II) complexes
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Overall enthalpy and entropy of complex formation were calculated from stability constant measurements at different tempreture also experimental results

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Publication Date
Sat Jan 11 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Color Stability of Different Aesthetic Archwires (An In vitro study)
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Background: Coated aesthetic archwires are currently the existing solutions for the esthetic problem, but the color of these archwires tends to change overtime. This study was aimed to evaluate the color stability of different types of esthetic archwires from four different companies at different time periods after immersion of two different staining drinks which are tea and Pepsi cola. Materials and methods: 48 specimens were prepared, each specimen contains 10 aesthetic archwires; and were divided according to type of solution into two groups: A (tea) &B (Pepsi cola); each group contained 24 specimens (12 specimens were immersed in the staining solution as 4 specimens for each time intervals and 12 specimens were immersed in distilled wa

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