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Oscillation of third-order functional dynamic equations on time scales

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Science China Mathematics 2011年第12期54卷 2597-2614页

作者： SAKER samir H. College of Science Research Centre King Saud University P.O. Box 2455 Riyadh 11451 Saudi Arabia

We consider the nonlinear functional dynamic equation （p（t）[（r（t）x^△（t））^△]γ）^△＋q（t）f（x（τ（t））） =0, for t≥t0,on a time scale T, where γ〉 0 is the quotient of odd positive integers, p, r, τ- and q are positive rd-continuous functions defined on the time scale 1F, and lirut→∞ τ（t） = ∞. The main aim of this paper is to establish some new sufficient conditions which guarantee that the equation has oscillatory solutions or the solutions tend to zero as →∞ τ. The main investigation depends on the Riccati substitution and the analysis of the associated Riccati dynamic inequality. Our results extend, complement and improve some previously obtained ones. In particular, the results provided substantial improvement for those obtained by Yu and Wang [J Comput Appl Math, 225 （2009）, 531-540]. Some examples illustrating the main results are given.

关键词： oscillation third-order dynamic equations time scales

Global asymptotic stability for a SEI reaction-diffusion model of infectious diseases with immigration

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International Journal of Biomathematics 2018年第3期11卷 289-305页

作者： Salem Abdelmalek samir Bendoukha Department of Mathematics University of Tebessa 12002 Algeria Department of Electrical Engineering College of Engineering Yanbu Taibah University Saudi Arabia

This paper studies the local and global stability of solutions for a spatially spread SEI epidemic model with immigration of individuals using a Lyapunov functional. It is shown that in the presence of diffusion, the unique steady state remains globally stable. Numerical results obtained through Matlab simulations are presented to confirm the findings of this study.

关键词： SEI epidemic model reaction-diffusion global asymptotic stability Lyapunov functional.

Recommending the IHACRES model for water resources assessment and resolving water conflicts in Africa

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Journal of Arid Land 2011年第1期3卷 40-48页

作者： samir Mohammad ali alredaisy Department of Geography Faculty of EducationUniversity of Khartoum

The International Association of Hydrological Sciences （IAHS） recognized the lack of hydro- logical data as a world-wide problem in 2002 and adopted the Prediction of Ungauged Basins （PUB） as a decadal research agenda during the period of 2003 to 2012. One of the objectives is to further develop methodologies for prediction in ungauged basins and to reduce uncertainties in model prediction. Estimation of stream flows is required for flood control, water quality control, valley habitat assessment and water budget of a country. However, the majority of water catchments, streams and valleys are ungauged in most developing countries. The main objective of this paper is to introduce the IHACRES （Identification of Hy- drographs and Components from Rainfall, Evaporation and Stream） model into African hydrological plan- ning as a methodology for water resources assessment, which in turn can be used to resolve water conflicts between communities and countries and to study the climate change issues. This is because the IHACRES model is applied for the estimation of flows in ungauged catchments whose physical catchments descriptors （PCDs） can be determined by driving variables （i.e. rainfall and temperature）; and also in gauged streams but whose gauging stations are no longer operational but historical data are available for model calibration. The model provides a valuable insight into the hydrologic behaviour of the upper water sources for valleys as well as provides a useful methodology for water resources assessment in situations of scarce financial resources in developing countries. In addition, it requires relatively few parameters in its calibration and has been successful applied in previous regionalization studies. It will also make possible the equitable distri- bution of water resources in international basins and rivers＇ catchments. This paper does not apply the model anywhere, but recommends it as a methodology for water resources assessment in order to cure water

关键词： ungauged catchment water resources assessment rainfall runoff lumped models Nile Basin Africa

Topical tacrolimus in anterior segment inflammatory disorders

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Eye and Vision 2017年第1期4卷 30-36页

作者： samir S.Shoughy The Eye Center and the Eye Foundation for Research in Ophthalmology PO Box 55307Riyadh 11534Saudi Arabia

Immune mediated inflammatory anterior segment diseases are variable and their management requires intense *** with topical steroids is associated with serious ocular side *** order to overcome the potentially blinding complications of topical steroids,immunomodulatory drugs are being used more *** is a calcineurin inhibitor that induces suppression of T lymphocytes activity and reduction of ocular *** was recently investigated for application in various anterior segment inflammatory *** this review,we will discuss the therapeutic application of topical tacrolimus as a steroid-sparing agent in treating T cell mediated anterior segment inflammation.

关键词： Tacrolimus Topical Ocular Immune-mediated T cells

Recent advances in fermented feeds towards improved broiler chicken performance, gastrointestinal tract microecology and immune responses: A review

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Animal Nutrition 2019年第1期5卷 1-10页

作者： Sugiharto Sugiharto samir Ranjitkar Department of Animal Science Faculty of Animal and Agricultural Sciences Diponegoro University Department of Animal Science (Immunology and Microbiology) Aarhus University

Previously, fermentation has been associated with methods that improve the nutritional value of unconventional feed ingredients for broilers. In recent decades, the fermentation process has been employed to produce functional feeds that have the potential to improve broiler gastrointestinal tract microecology, health and production performance. Some of the functional ingredients found in fermented feed include lactic acid bacteria(LAB), lactic acid and other organic acids, and appear to play major roles in determining the beneficial effects of fermented feed on broiler gut health and performance. Unlike the pig, the available literature on broiler fermented feed is still rather limited. This review describes recent advances in the use of fermented feed(on the basis of conventional and unconventional feed ingredients) in broilers. Similarly, this review also shows that additional research is necessary to exploit fermented feed as a viable food source in broiler nutrition.

关键词： Broiler Fermented feed Growth performance Gut health Immunity

Assessment of the Socio-Demographic Factors Associated with the Satisfaction Related to the Childbirth Experience

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Open Journal of Obstetrics and Gynecology 2014年第10期4卷 585-611页

作者： Elie al Ahmar samir Tarraf Faculty of Medicine and Medical Sciences Holy Spirit University of Kaslik Mount Lebanon Lebanon

Assessment of the socio-demographic factors associated with the satisfaction is related to the childbirth experience. Objective: A mother’s satisfaction with the childbirth experience may have instant and lasting effects on her wellbeing, and on the bonding with her infant. The main aim of the study was to assess which socio-demographic factors are associated with this satisfaction. Most factors that authors agree on are: Pain intensity, personal control, self-efficacy, length of labor, method of delivery and numerous other demographic factors. Design: A cross-sectional study. Data was collected using a self-reported survey. Settings: The sample consisted of 100 women, selected from St Georges Hospital and CHU-NDS, who had to speak Arabic and had given birth in the past three days prior to interview. Methods: The multiple linear regressions and the mean test were used to assess which factors were associated with a positive childbirth experience. The Mackey childbirth satisfaction scale, three items from the Wijma delivery Expectancy/Experience questionnaire, a seven item mastery scale developed by Pearlin and Schooler and a background questionnaire were filled by women. Findings: Factors that were linked to a positive birth experience were: Higher age, multiparous women, higher education, high monthly income, unemployment, childbirth preparation, high personal control and self-efficacy, high childbirth and labor pain, fulfilled expectations, shorter period of labor and instrumented delivery. Conclusion: This study demonstrates that satisfaction with the childbirth experience is multi-dimensional with diverse factors foreseeing diverse dimensions of satisfaction.

关键词： Childbirth Experience Satisfaction Personal Control Self-Efficacy Mother

Mitigating the catastrophic impacts of torrential rivers in semi-arid environments: a case of the Gash River in eastern Sudan

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Journal of Arid Land 2011年第3期3卷 174-183页

作者： samir Mohammad ali alredaisy Department of Geography Faculty of EducationUniversity of Khartoum

The climatic, geomorphic, hydrologic and aquifer characteristics of the torrential Gash River across mountainous areas, in far eastern Sudan, were analyzed in order to mitigate its recurring catastrophic impacts. Hydrologic and climatic data and interpretation of Gash River satellite images were from relevant research works carried out in Gash Basin from 1985 to 2008. The results indicated that the total catchment area of Gash River is about 21,000 km2, and the basin area is 31,000 km2. The total length of Gash River is 450 km and the average slope is 200 cm/km. The width of the catchment varies from 30 m to 90 m and that of the basin is from 100 m to 800 m, and the course of the river is varied. During the period of 1980？2008, the mean annual rainfall was 250 mm and the mean annual discharge was 6.8 ×10~8 m^3, and the flooding is approximately one time per 5 years. Torrential floods measured at Kassala town since 1907 showed that an absolute maximum discharge was 876 m3/s and a mean maximum discharge was 365 m3/s. These characteristics differ widely between catchment and basin areas. The author proposes that, by analyzing the climatic, geomorphic, hydrologic and aquifer characteristics of the Gash River and considering the role of community, a concise database could be provided to formulate the aquifer, geomorphic, hydrologic and climatic （AQUIGEOHYCLIM） regional approach to mitigate Gash River recurring catastrophic impacts.

关键词： AQUIGEOHYCLIM Gash River basin climate geomorphology hydrology mitigation water management

Vibration-based crack prediction on a beam model using hybrid butterfly optimization algorithm with artificial neural network

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Frontiers of Structural and Civil Engineering 2022年第8期16卷 976-989页

作者： Abdelwahhab KHATIR Roberto CAPOZUCCA samir KHATIR Erica MAGAGNINI Structural Section DICEA Polytechnic University of MarcheAncona 60131Italy Faculty of Civil Engineering Ho Chi Minh City Open UniversityHo Chi Minh City 700000Vietnam

Vibration-based damage detection methods have become widely used because of their advantages over traditional *** paper presents a new approach to identify the crack depth in steel beam structures based on vibration analysis using the Finite Element Method(FEM)and Artificial Neural Network(ANN)combined with Butterfly Optimization algorithm(BOA).ANN is quite successful in such identification issues,but it has some limitations,such as reduction of error after system training is complete,which means the output does not provide optimal *** paper improves ANN training after introducing BOA as a hybrid model(BOA-ANN).Natural frequencies are used as input parameters and crack depth as *** data are collected from improved FEM using simulation tools(ABAQUS)based on different crack depths and locations as the first ***,data are collected from experimental analysis of cracked beams based on different crack depths and locations to test the reliability of the presented *** proposed approach,compared to other methods,can predict crack depth with improved accuracy.

关键词： damage prediction ANN BOA FEM experimental modal analysis

ON THE SUPERSTABILITY OF THE PEXIDER TYPE GENERalIZED TRIGONOMETRIC FUNCTIONal EQUATIONS

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Acta Mathematica Scientia 2014年第6期34卷 1749-1760页

作者： Driss ZEGLAMI Ahmed CHARIFI samir KABBAJ Department of Mathematics E.N.S.A.M Moulay Ismail University Department of Mathematics Faculty of SciencesIbn Tofail University

The aim of this paper is to investigate the superstability problem for the pexiderized trigonometric functional equation∑ v∈Φ∫Kf（xkv（y）k^-1）dwK（k）= Φ g（x）h（y）, x, y ∈ G,where G is any topological group, K is a compact subgroup of G, ωK is the normalized Haar measure of K, Φ is a finite group of K-invariant morphisms of G and f, g, h are continuous complex-valued ***, we have generalized the results of stability for d＇alembert＇s and Wilson＇s equations by R. Badora, J. Baker, B. Bouikhalene, P. Gavruta, S. Kabbaj, Pl. Kannappan, G. ***, J.M. Rassias, A. Roukbi, L. Sz′ekelyhidi, D. Zeglami, etc.

关键词： superstability generalized Pexider d'alembert equation Wilson's functional equation group of morphisms