The avoidance strategy of prey to predation and the predation strategy for predators are important topics in evolutionary biology. Both prey and predators adjust their behaviors in order to obtain the maximal benefits and to raise their biomass for each. Therefore, this paper is aimed at studying the impact of prey’s fear and group defense against predation on the dynamics of the food-web model. Consequently, in this paper, a mathematical model that describes a tritrophic Leslie-Gower food-web system is formulated. Sokol-Howell type of function response is adapted to describe the predation process due to the prey’s group defensive capability. The effects of fear due to the predation process are considered in the first two levels

This research aims to investigate the effect of four types of nanomaterial on the Marshall properties and durability of warm mix asphalt (WMA). These types are; nano silica(NS), nano carbonate calcium (NCC), nano clay(NC), and nanoplatelets (NP). For each type of Nanomaterial, three contents are tried as following; NS(1%, 3%, and 5%), NCC(2%, 4%, and 6%), NC(3%, 5%, and 7%), and NP (2%, 4%, and 6%) by weight of asphalt cement. Following Marhsall mix design method, the optimum asphalt cement content is determined, thereafter the optimum dosage for each nanomaterial is obtained based on the highest Marshall stability value. The durability of the control mix (no nanomaterial) and modified mixtures have been compared based on moisture damage, r

Drilling solutions can be considered as an intricate mixture comprising of number of chemical additives which aid specific needs such as controlling the rheological properties and reducing corrosion. Inhibitors are substances that are added in small concentrations to corrosive environment to decrease the corrosion. Their applications can be found in drilling equipments. The effect of adding Zinc Sulphate and Carboxymethyl Cellulose to study their influence on the corrosion of carbon steel in Bentonite mud has been evaluated using Weight Loss Technique. This study focuses on determining rheological properties and corrosion characteristics. Results show CMC and ZnSO₄ work as inhibitors when added to the Bentonite with inhibition

من أجل الإجابة على التساؤل المتعلق بمشكلة البحث وهو؛ ماهي الصعوبات التي تواجه المدرسين باستخدام أساليب التدريس الحديثة بدرس التربية الرياضية للمرحلة المتوسطة؟ والعمل على إيجاد الحلول المناسبة لهذه الصعوبات. استخدم الباحثين المنهج الوصفي بالأسلوب المسحي على عينة من مدرسي ومدرسات التربية الرياضية في محافظة ديالى في المدارس المتوسطة والبالغ عددهم (81) مدرساً ومدرسة، وبعد إعداد الاستبانة الخاصة بالبحث وتوزيع

The availability of low- cost adsorbent namely Al-Khriet ( a substance found in the legs of Typha  Domingensis) as an agricultural waste material, for the removal of lead and cadmium from aqueous solution was investigated. In the batch tests experimental parameters were studied, including adsorbent dosage between (0.2-1) g, initial metal ions concentration between (50-200) ppm (single and binary) and contact time (1/2-6) h. The removal percentage of each ion onto Al-Khriet reached equilibrium in about 4 hours. The highest adsorption capacity was for lead (96%) while for cadmium it was (90%) with 50 ppm ions concentration, 1 g dosage of adsorbent and pH 5.5. Adsorption capacity in the binary mixture were reduce at about 8% for lead a

   The research aims to determine the nature of the effect of long . term finance with Net profit which get by the organization from a grubs of finance sources which the organization can choose among them to funding its operations it is  one of the basic necessities Net income . Despite this importance , however there is a distinct lack of many Iraqi organizations in the study of the relationship effect of between these two variables and this the reaserch problem .

          The data of research were obtained the annual guide of Iraqi market for securities where a data of sample of Iraqi Banks was selected which were five banks from 2004 to 2007 , most of the analysis re

The goal of current researcher to know the impact of strategic Jigsaw in the collection of hypertext and geographic operations of science students at the preparatory stage And that by checking the following 1.There is no difference statistically significant at the significance level 0.05 between the experimental group students who were studying strategy Jigsaw and between the control group students who studied in the usual way traditional degrees in the average achievement in the subject of geographical 2.There is no difference statistically significant at the significance level 0.05 between the experimental group students who were studying strategy Jigsaw and between the control group students who studied in the usual way traditional av