Background and purpose: Arterial embolism is one of the most prevalent cause of transient ischemic attack (TIA) and other types of brain ischemias and about 5o% of TIA patiens have vascular stenosis. Therefore the presence of mild atherosclerotic plaques in carotid arteries, as a source of embdlism in causing TIA and other brain strokes are of a great importance.In present study the stroke patients were survaied specially for the size of infarct region by carotid arteries Doppler sonography. The relationship between the size of infarct region and degree of stenosis and tye of carotid arteries plaque were analysed.Materials and Methods: This cross sectional study, was conducted on 100 patients with cerebral infarction in the region of anterior CIRCULATION referred to radiology department of Sina hospital.Patients selection was based on the date of admission and after C.T scanning, extracranial carotid arteries were survaied by Doppler sonography (Aloka-SSD-1700). Registration of results of this study was done in the year 2000.Results: Plaques were seen in ipsilateral carotid artery in 49% of patients. Proximal internal carotid artery was the most common site of involvement (34%) and carolid bifurcation and distal common carolid artery were involved consequently.Frequency of stenosis, specially the compelete sterosis, increased proportionately with the size of infarct area. The occlusion with small, medium and large sized infarction was zero, 16 and 33.3 percent respectively.Conclusion: Frequency of stenosis, specially ipsilateral carotid stensis was strongly associated with large than small infarct (25% VS 3.3% p<0.05).

The main objective of this article is to establish a new model and find some vortex axisymmetric solutions of finite core size for this model. We introduce the hydrodynamical equations governing the atmospheric CIRCULATION over the tropics, the Boussinesq equation with constant radial gravitational acceleration. Solutions are expanded into series of Hermite eigenfunctions. We find the coefficients of the series and show the convergence of them. These equations are critically important in mathematics. They are similar to the 3D Navier-Stokes and the Euler equations. The 2D Boussinesq  equations preserve some important aspects of the 3D Euler and Navier-Stokes equations such as the vortex stretching mechanism. The inviscid 2D Boussinesq equations are known as the Euler equations for the 3D axisymmetric swirling flows.This model is the most frequently used for buoyancy-driven fluids, such as many largescale geophysical flows, atmospheric fronts, ocean CIRCULATION, clued dynamics. In addition, they play an important role in the Rayleigh-Benard convection.

Atmospheric CIRCULATION patterns play an important role in producing environmental phenomena, particularly in temperate zones. Therefore, identification of atmospheric CIRCULATION patterns that control the climate of Iran is essential.In the present research, the principal component analysis (PCA) and cluster analysis (CA) techniques were used to classify the daily atmospheric CIRCULATION patterns over Iran in a synoptic scale. For this purpose, the mean daily 500 hpa and sea level pressure (SLP) grided data sets during 1950-2006 was retrieved from NCEP/NCAR and used. The used data consists of 408 points regularly distributed over the region, 20° N - 60° N and 20° E - 80° E, with the 2.5 degree spatial resolution. By applying the S-mode PCA, the 408 grids covering the study area, were reduced into 9 PCs accounting for 94 percent of total variance. The 9 leading PCs were rotated using varimax rotation in order to obtain simpler and physically interpretable results. Then, all days (20828) were classified into 18 groups by applying K-means clustering on the resultant 9 PC scores. The composite maps of the identified groups were drawn and represented as the atmospheric CIRCULATION patterns. Monthly distribution and long term trends of the identified CIRCULATION patterns were also present. The results show a significant difference in patterns, frequency of weather types and their direction to Iran. According to the obtained results, the presented method in this research can consider as a quantitative and certain method to derive atmospheric CIRCULATION patterns. Also, this pattern can be as an indicator to analyze environmental phenomena and synoptic patterns relationship.

In the presence of aortoiliac occlusive peripheral artery disease (AIOPAD), which can cause significant mortality and morbidity when untreated, . . .

In this paper، a new experimental method is applied، and the capability of different Loss Control Materials (LCMs) in bentonite mud – which has the highest use in Iran’ s oil and gas wells – is investigated. At first، particle size distribution of LCMs is calculated based on API standards. Then، the loss of bentonite mud in different slots is evaluated using Bridging Materials Testing (BMT) apparatus. Usage of three dimensional fractures is one of the most important points of this research، which makes the experiment conditions so similar to the real conditions of well. It should be mentioned that LCMs show their best efficiency only when they can internally block the fractures. Also، in this research، RI-LQ material is for the first time used to control the lost CIRCULATION of bentonite mud. The results of these experiments showed that a mixture of RI-LQC and Quick Seal with Concentrations of 20 and 5 pounds per barrel and RI-LQC and RI-LQF mixtures with concentrations of 18 and 7 pounds per barrel have the least amount of loss CIRCULATION and are effective in controlling sever losses.