Optimization of Green-Times at an Isolated Urban Crossroads

We propose a model for the intersection of two urban streets. The traffic status of the crossroads is controlled by a set of traffic lights which periodically switch to red and green with a total period of T. Two different types of crossroads are discussed. The first one describes the intersection of two one-way streets, while the second type models the intersection of a two-way street with an one-way street. We assume that the vehicles approach the crossroads with constant rates in time which are taken as the model parameters. We optimize the traffic flow at the crossroads by minimizing the total waiting time of the vehicles per cycle of the traffic light. This leads to the determination of the optimum green-time allocated to each phase.Comment: 8 pages, 6 eps figures, more explanation added. To appear in EPJ

Determination of optimum injection flow rate to achieve maximum micro bubble drag reduction in ships; an experimental approach

AbstractReduction in ship resistance, in order to decrease fuel consumption and also achieve higher speeds, has been the topic of major research over the last three decades. One of the most attractive ideas in this field is micro bubble drag reduction, which attempts to obtain optimum injection flow rate based on ship specifications. The model test results of a 70 cm catamaran model was used to quantify the effect of air injection rate on drag reduction, and to estimate a simple formulation for calculating an efficient injection rate by considering the main parameters of the ship, such as: length, width and speed. The test results show that excessive air injection decreases the drag reduction effect, while suitable injection reduces total drag by about 5%–8%

Derivation of extracts from Persian Gulf sea cucumber (Holothuria leucospilota) and assessment of its antifungal effect

Sea cucumber is presented as a potential marine source of antimicrobial compounds. The purpose of this study is to evaluate antifungal effects of sea cucumber, Holothuria leucospilota, extracts on Aspergillus niger and Candida albicans. Methanol and chloroform extracts of the body wall, gonad and intestine of sea cucumber, H. leucospilota, collected from Persian Gulf, were evaluated for their antifungal activity against A. niger and C. albicans. The activity was determined using serial dilution method. Antifungal activity, minimum inhibitory concentration and minimum fungicidal concentration were evaluated by the different concentrations. Results showed that each of the extracts had antifungal effect at specified concentrations on the A. niger. All examined concentrations of Gonad methanol and intestine chloroform extracts had no inhibitory effect on C. albicans. Chloroform extracts of gonad and intestine had more fungicidal effect against A. niger compared with C. albicans. Gonad chloroform extracts showed more fungicidal effect on the C. albicans at concentrations of 2.5, 5 and 10 mg/ml. Sea cucumber extract can be considered as an antifungal agent in various industries such as medicine and pharmaceutical industry

Multi Vesicular Osseous Hydatid Disease of the Mandible- A Case Report

Hydatid disease is a common and major public health issue caused by parasite Echinococcus granulosus. The highest prevalence of the parasite can be found in different parts of world like Africa, Australia, and South America. This infection can occurs in almost any part of the body. Here we present clinical, radiological, histological features and treatment of a multi vesicular osseous hydatid disease of the mandible in an Afghan 5 year old boy with a firm swelling in the right side of mandible

Evaluation of Russian wheat aphid resistance in cultivars and advanced lines of wheat under field conditions in Isfahan province, Iran

Host plant resistance is an economic and environmental friendly method for controlling Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko). To evaluate resistance of 15 cultivars and advanced lines of wheat to RWA under field conditions, an experiment was conducted in a randomized complete block design with 4 replications in Mobarake region (Isfahan province, Iran) during 2001-2003. Four plants were harvested randomly from each plot in a weekly schedule and the numbers of settled aphids per plant were counted for both adults and nymphs, and the damage rate was estimated. Variance analyses were performed on pooled data from all samplings and correlation coefficients among resistance criteria were calculated. Results showed that maximum adult / plant was on Mahdavi, M-78-14, and M-78-19; and minimum adult / plant was on M-73-4, M-73-18, Alvand and M-75-7. Maximum number for nymphs was estimated on M-75-10 and M-78-20 and the minimum number on M-73-4. Mahdavi and M-75-7 had the highest damage rate and M-73-18, M-73-4 and M-78-7 had the lowest. Positive and significant correlation coefficients were found between damage rate with adult aphid / plant, and between the number of adults and nymphs. Therefore, damage rating could be used as a suitable criterion for evaluating resistance of wheat to RWA under field conditions. To assess influence of the pest on yield and yield components, a similar allotment was cultivated and sprayed two times with Metasystox. At harvest, yield and yield components were determined in sprayed and unsprayed allotments, and consequently, the means of yield and yield components between these two allotments were compared using t-student test. The mean comparisons showed that there was no significant difference between sprayed with unsprayed allotments for yield and yield components

In vitro cytotoxic and anti-cancer effects of body wall for sea cucumber (Holothuria leucospilota)

In recent years efforts to find bioactive compounds from live organisms especially marine animals have been increased. In the present study, the anticancer and cytotoxic effects of sea cucumber body walls (Holothuria leucospilota) were investigated. For this purpose, sea cucumbers were collected from Larak Island at depths of 10 to 30 m and extraction process was done with methanol and diethyl ether solvent which then concentrated by rotary evaporator (40℃) following lyophilization with vacuum freeze dryer. XTT method was used to investigate anticancer and cytotoxic effects of body wall extracts. The results showed that the methanolic extract could prevent proliferation of human oral epidermoid carcinoma cells (KB) at concentrations of 100 and 500 μg/ml. The diethyl etheric extract also could prevent proliferation of KB at 500 μg/ml concentration. Overall result showed that sea cucumber body wall had a strong cytotoxic effect on normal cell line (Human embryonic kidney cell [HEK]) which can be used as potent cytotoxic material. However these extracts did not show significant therapeutic value against KB cells