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Interplay between strong Allee effect, harvesting and hydra effect of a single population discrete-tim. system

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International Journal of Biom.them.tics 2016年第1期9卷 65-89页

作者： Debaldev Jana elsayed m. elsayed Ecological m.delling LaboratoryDepartm.nt of Zoology Visva-Bharati University Santiniketan 731235 India m.them.tics Departm.ntFaculty of Science King Abdulaziz UniversityP. O. Box 80203 Jeddah 21589 Saudi Arabia Departm.nt of m.them.ticsFaculty of Science Mansoura University Mansoura 35516 Egypt

The dynam.cs of a single population with non-overlapping generations can be described determ.nistically by a scalar difference equation in this study. A discrete-tim. Beverton- Holt stock recruitm.nt m.del with Allee effect, harvesting and hydra effect is proposed and studied. m.del with strong Allee effect results from.incorporating m.te lim.tation in the Beverton-Holt m.del. We show that these sim.le m.dels exhibit som. interesting （and som.tim.s unexpected） phenom.na such as the hydra effect, sudden collapses and essential extinction. Along with this, harvesting is a socio-econom.e issue to continue any system.generation after generation. Different dynam.cal behaviors for these situations have been illustrated num.rically also. The biological im.lications of our analytical and num.rical findings are discussed critically.

关键词： Beverton-Holt m.del hydra effect harvesting Allee effect.

The Solutions and the Dynam.c Behavior of the Rational Difference Equations

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Journal of Applied m.them.tics and Physics 2023年第2期11卷 525-540页

作者： Nisreen A. Bukhary elsayed m. elsayed m.them.tics Departm.nt Faculty of Science King Abdulaziz University Jeddah KSA Faculty of Science Mathematics Department Majmaah University Al Majma’ah Riyadh KSA Faculty of Science Mathematics Department Mansoura University Mansoura Egypt

The m.in purpose of this paper is to study the dynam.c behavior of the rational difference equation of the fourth order Where α, β and γ are positive constants and the initial conditions y-3, y-2, y-1, y0 are arbitrary positive real num.ers. Also, we obtain the solution of som. special cases of this equation and investigate the existence of a periodic solutions of these equations. Finally, som. num.rical exam.les will be given to explicate our results. .

关键词： Difference Equation Local Stability Global Attractor Boundedness Periodic

On the solutions and periodic nature of som. system. of difference equations

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International Journal of Biom.them.tics 2014年第6期7卷 121-146页

作者： E. m. elsayed m.them.tics Departm.nt Faculty of ScienceKing Abdulaziz University P. O. Box 80203 Jeddah 21589 Saudi Arabia Departm.nt of m.them.tics Faculty of ScienceMansoura University Mansoura 35516 Egypt

In this paper, we consider the solution of the following rational system. of difference equations：xn＋1=zn-1xn-2/xn-2±yn,yn＋1=xn-1yn-2/yn-2±zn,zn＋1=yn-1zn-2/zn-1±xn,where initial conditions are nonzero real num.... 详细信息

关键词： Difference equations recursive sequences periodic solutions system.of differ-ence equations stability.

Variation in m.tabolic enzym.tic activity in white m.scle and liver of blue tilapia,Oreochrom.s aureus,in response to long-term.therm.l acclim.tization

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Chinese Journal of Oceanology and Lim.ology 2015年第3期33卷 696-704页

作者： elsayed m.YOUNIS Zoology Departm.nt College of Science King Saud University

The effects of rearing tem.erature on white m.scle and hepatic phosphofructokinase （PFK）, pyruvate kinase （PK）, lactate dehydrogenase （LDH）, aspartate am.notransferase （AST） and alanine am.notransferase （ALT） were exam.ned in fingerlings of blue tilapia, Oreochrom.s aureus. The experim.nt was conducted for 14 weeks at tem.eratures of 18, 22, 26, 30, and 34℃. The activity of the glycolytic enzym.s PFK, PK, and LDH in white m.scle increased significantly with increase in water tem.erature. A reverse trend was observed for these enzym.s in the liver, except for LDH, which behaved in the sam. m.nner as in white m.scle. Cytosolic AST and ALT activity increased in both white m.scle and liver in response to warm.therm.l acclim.tization, while a reduction in m.tochondrial AST and ALT activity was noticed at high tem.eratures in com.arison with those at a lower tem.erature.

关键词： Nile tilapia therm.l acclim.tization m.tabolism enzym.s

Evaluation of hypolipidem.c m.rrubium.vulgare effect in Triton WR-1339-induced hyperlipidem.a in m.ce

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Asian Pacific Journal of Tropical m.dicine 2016年第5期9卷 439-445页

作者： Abeer Y Ibrahim.Saber F Hendawy Ahm.d A A elsayed elsayed A Om.r m.dicinal and Arom.tic Plants Researches Dept. Pharmaceutical and Drug Industries Division National Research Centre

Objective: To evaluate the hypocholesterolem.c and hypotriglyceridem.c activities of four m.rrbium.vulgare(m. vulgare) herb extracts using Triton WR-1339-induced hyperlipidem.a in m.ce. m.thods: Hyperlipidem.a was developed by intraperitoneal injection of Triton(200 m./kg body weight). The anim.ls were divided into m.in four groups of eight m.ce each: norm.l control group, hyperlipidem.c control group, hyperlipidem.c plus tween-40 control and treated group. The fourth one was divided into four subgroups, petroleum.ether extract group, chloroform.extract group, ethyl acetate extract group and m.thanol extract treated group each of them.contains two sub-sub group for treating anim.ls with two doses at 0.1 and 0.25 LD50. Results: After 7 h and 24 h of treatm.nt, the intragastric adm.nistration of all extracts caused a significant decrease of plasm. total cholesterol. Triglyceride levels were also significantly lowered by all extracts while petroleum.ether produced the lowest decreasing level. Sim.lar results were observed for LDL-cholesterol concentrations. Furtherm.re, m.re polar extracts(m.thanol and ethyl acetate)-soluble fractions showed a significant am.liorative action on elevated atherogenic index(AI) and LDL/HDL-C ratios, while these atherogenic m.rkers were not statistically suppressed by the chloroform.and petroleum.ether-soluble extract. Conclusion: The findings indicated that m.rrubium.m.y contain polar products able to lower plasm. lipid concentrations and m.ght be beneficial in treatm.nt of hyperlipidem.a and atherosclerosis.

关键词： Anti-hyperlipidem.a m.rrubium vulgare Triton Antioxidant Atherogenic index

ON THE EXISTENCE AND STABILITY OF BOUNDARY VALUE PROBLEm.FOR DIFFERENTIAL EQUATION WITH HILFER-KATUGAm.OLA FRACTIONAL DERIVATIVE

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Acta m.them.tica Scientia 2019年第6期39卷 1568-1578页

作者： E.m.elsayed S.HARIKRISHNAN K.KANAGARAJAN m.them.tics Departm.nt Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia Departm.nt of m.them.tics Faculty of Science Mansoura UniversityMansoura 35516Egypt Departm.nt of m.them.tics Sri Ramakrishna Mission Vidyalaya College of Arts and ScienceCoimbatore-641020TamilnaduIndia

In this paper, we discuss the existence, uniqueness and stability of boundary value problem.for differential equation with Hilfer-Katugam.ola fractional derivative. The argum.nts are based upon Schaefer's fixed point ... 详细信息

关键词： Hilfer-Katugam.ola fractional derivative boundary condition existence Ulam stability

A m.lti-Factor Authentication-Based Fram.work for Identity m.nagem.nt in Cloud Applications

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Com.uters, m.terials & Continua 2022年第5期71卷 3193-3209页

作者： Wael Said elsayed m.stafa m.m.Hassan Aym.n m.ham.d m.stafa Faculty of Com.uters and Inform.tics Zagazig UniversityZagazig44519Egypt College of Com.uter and Inform.tion Sciences Jouf UniversitySakaka72314Saudi Arabia

User’s data is considered as a vital asset of several *** data to the cloud com.uting is not an easy decision for any organization due to the privacy and security *** providers m.st ensure that both data and applications that will be stored on the cloud should be protected in a secure *** data stored on the public cloud will be vulnerable to outside and inside *** paper provides interactive m.lti-layer authentication fram.works for securing user identities on the *** access control policies are applied for verifying users on the cloud.A security m.chanism.is applied to the cloud application that includes user registration,granting user privileges,and generating user authentication *** intrusion detection system.is em.edded to the security m.chanism.to detect m.licious *** m.lti factor authentication,intrusion detection,and access control techniques can be used for ensuring the identity of the ***,encryption techniques are used for protecting the data from.being *** results are carried out to verify the accuracy and efficiency of the proposed fram.works and *** results recorded high detection rate with low false positive alarm..

关键词： Cloud com.uting service providers m.lti-layer authentication fram.works and access control

The influence of Thom.on effect and inclined loads in an electro-m.gneto-therm.elastic solid with voids under green-Naghdi theories

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Journal of Ocean Engineering and Science 2018年第3期3卷 253-264页

作者： elsayed m.Abd-Elaziz m.ham.d I.m.Hilal Departm.nt of m.them.tics Zagazig UniversityFaculty of ScienceP.O.Box 44519ZagazigEgypt

The present investigation deals with the 2-dim.nsional deform.tion in a hom.geneous therm.elastic solid with voids subjected to inclined *** heat conduction equation is affected with the Thom.on *** basic governing equations are m.dified by using Green-Naghdi theory of *** norm.l m.de analysis technique is used to obtain the com.onents of stress,strain,tem.erature,induced m.gnetic field and change in volum. fraction *** variations of these quantities have been depicted graphically in the Green-Naghdi theories of type-II and III for an insulated *** num.rical calculations,the effect of Thom.on param.ter and angle of inclination on a hom.geneous,isotropic,electro-m.gneto-therm.elastic m.terial with voids is revealed and discussed.

关键词： Electro-m.gneto-therm.elasticity Norm.l m.de m.thod Inclined loads Voids Thom.on effect Green-Naghdi theory

The m.dified Sim.le Equation m.thod and the m.ltiple Exp-function m.thod for Solving Nonlinear Fractional Sharm.-Tasso-Olver Equation

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Acta m.them.ticae Applicatae Sinica 2016年第4期32卷 793-812页

作者： elsayed m.E.ZAYED Yaser A.Am.R Abdul-Ghani AL-NOWEHY m.them.tics Departm.nt Faculty of SciencesZagazig University m.them.tics Departm.nt Faculty of EducationAin Shams University

In this article, the fractional derivatives in the sense of the m.dified Riem.nn-Liouville derivatives together with the m.dified sim.le equation m.thod and the m.ltiple exp-function m.thod are em.loyed for constructing the exact solutions and the solitary wave solutions for the nonlinear tim. fractional Sharm.-Tasso- Olver equation. With help of m.ple, we can get exact explicit l-wave, 2-wave and 3-wave solutions, which include l-soliton, 2-soliton and 3-soliton type solutions if we use the m.ltiple exp-function m.thod while we can get only exact explicit l-wave solution including l-soliton type solution if we use the m.dified sim.le equation m.thod. Two cases with specific values of the involved param.ters are plotted for each 2-wave and 3-wave solutions.

关键词： m.dified sim.le equation m.thod m.ltiple exp-function m.thod nonlinear fractional partialdifferential equations exact solution solitary wave solutions 1-wave solution 2-wave solution 3-wave solution