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ijs-4923
The Effect of Mutual Interaction and Harvesting on Food Chain Model
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       This paper treats the interactions among four population species. The system includes one mutuality prey, one harvested prey and two predators. The four species interaction can be described as a food chain, where the first prey helps the second harvested prey. The first and the second predator attack the first and the second prey, respectively, according to Lotka-Volterra type functional responses. The model is formulated using differential equations. One equilibrium point of the model is found and analysed to reveal a threshold that will allow the coexistence of all species. All other equilibrium points of the system are located, with their local and global stability being assessed. To back up the conclusions of the mathematical analysis, a numerical simulation examination of the model is carried out. The system's coexistence can be achieved as long as the harvesting rate of the prey population is lower than its intrinsic growth rate.

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Publication Date
Wed Aug 30 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Space-Charge Effect on Theoretical Design of the Electron Gun Operated under Finite Magnification Condition
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A computer theoretical s1udy has been carried out in field of opto - clcctroniccs, to design  an electron  gun using the space charge effect.

The   distribution  of   axial  potential    upon   the  two   -electrode

immersion  lens  of  (L=l4mm)  has been  carried   out   using   Poisons equation and the  tinite  clement  method;  knowing  the first 11nd second derivation  of  the    axial   potential   and  the  solution   of  paraxial   ray equation, the  optical   prop

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Publication Date
Tue Mar 01 2011
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The effect of differentiation strategy on achieve competitive advantage: survey comparison between the companies maintenance service
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Is to obtain competitive advantage legitimate objective pursued by all organizations to achieve, because they live today in environments of rapid change and dynamic in order to meet the demands of the customer changing as well as intense competition between the organizations, which requires them to get the location of competitive markets in order to do this will remain to do the building and strengthening competitive advantage to be able to achieve, but that this feature is not easy and is not only through the identification and use of a successful strategy for a competitive standard and then manage it successfully. Hence the research problem of determining the sources of differentiation strategy and its impact on the dimensions of compe

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Publication Date
Tue Oct 23 2018
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of Dividend Policy on Earnings Quality in The Companies listed in Iraq Stock Exchange
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The dividends is one of difficult and important decisions taken by the administration in the economic units, because this decision has a direct impact on the investor and economic unit, so the main objective of any investor is achieve earnings, as well as information borne by dividends about the earnings quality of the economic unit and the level and efficiency of management to achieving earnings.

The research aims at explaining the effect of the dividends policy on the earnings quality in the companies listed in the Iraq Stock Exchange. The Miller model was used to measu

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Publication Date
Sat Jul 08 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
The Effect of Coumarin Derivatives(compounds) on the Vibrio cholerae Isolates from Different Clinical Iraqi Sources
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From a large number of bacterial samples collected from different hospital in Iraq in central  health laboratory ,only ten isolates were identified primary as Vibrio. A number of  morphology and biochemical test were carried out to complete this identification that showed all bacterial isolates were related to Vibrio cholerae .In this study  all Vibrio isolates were investigated for Bio typing and the result showed that all (10) isolate were related to (Eltor biotypes) .Also, the susceptibility test towards eight antibiotics were carried  out .

Results shows that  ciprofloxacin , Norfloxacin, Erythromycin, Ampicillin,  ceftriaxone  and Amikacin were the most effective

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Publication Date
Fri Nov 01 2024
Journal Name
Egyptian Journal Of Veterinary Sciences
Contamination with Proteus and Staphylococcus spp. Effect on Physical Properties of Sheep Semen
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Publication Date
Thu Feb 06 2025
Journal Name
Iraqi Journal Of Agricultural Sciences
EFFECT OF TILLAGE WITH CHISEL PLOW ON SOIL MEAN WEIGHT DIAMETER AND POROSITY
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Publication Date
Sat Jun 03 2023
Journal Name
Iraqi Journal Of Science
Effect of Different Environmental and Nutritional Factors on Biosurfactant Production from Candida guilliermondii
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Yeast strain S9, which produced a high amount of biosurfactant, was isolated from pickledolive and identified as a strain of Candida guilliermondii using VITTEK 2 compact system, this strain was selected out of 13bioemulsifier producing strains. The effects of some environmental and nutritional factors on biosurfactant production were evaluated, the maximum value of E24% was observed at pH 4 which was 70% and the optimal temperature for biosurfactant production was 30 °C, E24% was 75%. Among different edible and heavy oils, the sesame oil and heavy oil 150 were the best carbon sources in production of biosurfactant, E24% was82% and 78% respectively and among different organic and inorganic nitrogen sources, the yeast extract was the bes

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Publication Date
Sun Sep 01 2019
Journal Name
Al-khwarizmi Engineering Journal
Effect of Shot Peening on Fatigue Properties for Corroded and Uncorroded (CK35) Steel
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The traction property is one of the important mechanical properties, especially the rotary parts which are subjected to constant and variable loads There are many methods used to improve this property, and the shoot peening by metal balls is considered the most critical one. the study focuses on this characteristic of steel CK35 used in many engineering applications as the rotating shafts and railway This study shows that the fatigue strength is improved by14% after shoot peening with metal balls. The study includs the rehabilitation of damaged samples as a result of fatigue corrosion. The standard solution adopted was 36% MgCl­2 with a 30 days immersion period. These samples has been improved by 6% after it decreased by18% d

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Publication Date
Sun May 14 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Effect of Yogurt and Bifidobacterium on Cryptosporidium parvum Infection In Experiential Infected Mice
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        This study aimed to collected 150 feces sample from calves suffering sever diarrhea ,then there were isolation and purification of Cryptosporidium parvum oocyst from samples contain it. These oocysts were used to induce experimental infection in the Immunosupperessed mice, then the mice treated by Bifidium bacteria , its supernatant and local yogurt were used for bacterial isolation.

       This study showed that the local yogurt was the best treatment which led to stop oocyst shedding from the mice in the 8th day after treatment under sufficient treatment (89.72%) , at the same time the mice treated with bacteria stopped the oocyst shedd

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Publication Date
Sun Mar 01 2020
Journal Name
Iraqi Journal Of Physics
Optimization Procedures using Effect of Etalon Finesse and Driving Term on Optical Bistability
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        In this work, analytical study for simulating a Fabry-Perot bistable etalon (F-P cavity) filled with a dispersive optimized nonlinear optical material (Kerr type) such as semiconductors Indium Antimonide (InSb). Because of a trade off between the etalon finesse values and driving terms, an optimization procedures have been done on the InSb etalon/CO laser parameters, using critical switching irradiance (Ic) via simulation systems of optimization procedures of optical cavity. in order to achieve the  minimum switching power and faster switching time, the optimization parameters of the finesse values and driving terms on optical bistability and switching dynamics must be studied.

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