Background: This in vitro study evaluated the effect of canal dryness and flaring on the accuracy of two electronic apex locators for working length (WL) determination. Materials and methods: Sixty extracted teeth were used, after access opening was done, the occlusal surface was flattened to create stable reference point. The teeth were randomly divided into two equal main groups of flared and unflared group each one of 30 teeth. The flaring was done with Gates Glidden drills. The two main groups were further subdivided into two subgroups: dry canal and wet canal using 5.25% sodium hypochlorite groups, Electronic WL of each sample was determined using both Root ZX and i-Root apex locator. Consequently, histologic WL was determined by shav

The aim of this paper is to describe an epidemic model when two SI-Type of diseases are transmitted vertically as well as horizontally through one population. The population contains two subclasses: susceptible and infectious, while the infectious are divided into three subgroups: Those infected by AIDS disease, HCV disease, and by both diseases. A nonlinear mathematical model for AIDS and HCV diseases is Suggested and analyzed. Both local and global stability for each feasible equilibrium point are determined theoretically by using the stability theory of differential equations, Routh-Hurwitz and Gershgorin theorem. Moreover, the numerical simulation was carried out on the model parameters in order to determine their impact on the disease

The organizations, represented by its Management, are working hard in various ways to identify the environmental disturbances that occur in their environment and to investigate and follow up the movement of these disturbances and to respond to them through the decisions they make in an attempt to keep pace with the work and sustainability of their activities, including those decisions, marketing decisions taken by the environmental disturbulence in the market of the organization, the inability of these organizations to read the indicators of these disturbulence correctly displays their marketing effectiveness to vibration and decline in the negative.The current research is based on a fundamental problem that envi

The performance of single and two stage solar concentrator were studied ' " The ratio of the primary to the secondary mirrors diameter is taking to be 0.5, depending on the theoretical calculation for the accumulated energy by the concentrator with ratio between 0.0 to 0.9. The design of the systems were designed and examined by using a ray-tracing program. The efficiency of the single and the two stage concentrators are calculated and compared with and without cooling systems.

الخلاصة لقد شكل المحافظون الجدد وهم بالأساس نخبة من المثقفين ومن السياسيين الأمريكيين كتلة ضغط كبيرة التأثير على الإدارة في عهد الجمهوريين. حمل هؤلاء المحافظون مشروعاً إيديولوجياً البسوه لسلطة الجمهوريين وهو يهدف إلى جعل أمريكا سيدة العالم من دون منازع خاصة بعد انهيار الاتحاد السوفييتي ونهاية الحرب الباردة. واكب هذا الحدث التاريخي الكثير من الأفكار ومنها (نهاية التاريخ)، وصراع الحضارات، وكذ

Over the past ten years, tumor markers have played an increasingly important role in clinicaloncology. This trend is expected to continue as technology advances and our knowledge of thehuman body and disease processes grows. In the treatment of cancer, tumor markers are widelyused for a variety of purposes, including screening, selecting a management strategy,determining the prognosis, and post-therapy follow-up. A comprehensive of the fundamentalsof pathophysiology and identification strategies for each specific malignancy is necessary fortheir prudent application in clinical practice. Oncology's use of cancer biomarkers hastransformed the way that cancer is treated, and led to notable improvements in patient outcomesand cancer tre

The research aims to know the question asking skills in terms of levels, conditions, classification, and types. The research limited to the literature that dealt with the importance of questioning for students and teachers. The most important term used in the research is the skill (Ryan defined it as "the ability to perform with great efficiency, accuracy, and ease). The results of the research are as follows: 1. the questions asked by the schoolteacher within the assessment of students' learning. 2. Teachers should focus on the lower levels of learning (remembering, understanding and comprehension) and then evaluating students at the higher levels (synthesis and evaluation). 3. Teacher with good knowledge can skillfully use the question

To test the effect of 4 levels of nitrogen (i.e. 0, 45, 90 and 135 Kg N ha^-1) as urea (46% N) and 3 levels of phosphorus (i.e. 0, 17.5 and 35 Kg P ha^-1) as triple superphosphate (21.8% P) on yield and concentration of dill (Anethum graveolens L. local cultivar) seed oil this experiment was carried out during winter season of 1999 - 2000 at the experimental field of Agriculture College, Abu-Ghraib.

 Both fertilizers were applied in two equal splits, first at seeds sowing and the second was added one month after emergence. Dried and ground seed samples were subjected to water distillation for extraction of volatile oils

 Result indicated that fertilization of dill plants with 90 Kg N