405 research outputs found

    New algorithms to minimize handoff latency in AMTree protocol

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    In active networks, programs can be injected to network elements (routers/switches). This allows programmers to enhance existing protocols or deploy new protocols. AMTree protocol is an active network based protocol that makes sending packets to receivers, after source migration, an efficient process. In AMTree protocol, after source migration, handoff latency computed from the time of reconnecting to a new base station until finding nearest core to the mobile source. In this paper the authors present two new algorithms to minimize the handoff latency in AMTree protocol. They show that handoff latency is much lower than that of AMTree handoff algorithm if the mobile source connects to a base station which is subscribed to the multicast group

    Air quality and variations in PM10 pollutant concentration in western iran during a four-year period (2008-2011), Kermanshah-a case study

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    The present study explored the quality of PM10, over a four-year period in the western part of Iran. A total of 1334 samples were collected from air pollution measurement stations in Kermanshah. Statistical analysis was carried out using the SPSS ver.14. The results showed that the total percent change in PM10 over a period of 4 years was 10.04, 59.2, 26.4, 0.7 and 3.3. The highest and the lowest frequencies of PM10 occurred in February with 37.7, June and July with 0; winter and summer months with 21.96 and 4.81, respectively. The results are depicted that the air quality in July, the summer months and 2008 was worst in terms of PM10 concentration, which was mainly due to the fluctuations and acute entrance of dust particles into western Iran. Hence, the reduction in such emissions is indispensable and requires extensive and considerable cooperation between the government of Iran and the neighbouring countries. © School of Engineering, Taylor�s University

    Hepatitis A virus and Hepatitis E virus seroprevalence among blood donors in Tehran, Iran

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    Background: Hepatitis A virus (HAV) and Hepatitis E virus (HEV) are both transmitted by the fecal-oral route and are known as the leading causes of acute viral hepatitis in the world, especially in developing countries. There is a lack of updated data on HAV and HEV seroprevalence in Iran. Objectives: The aim of this study was to determine the seroprevalence of HAV and HEV among a group of blood donors in Tehran, Iran. Materials and Methods: A cross-sectional study was performed from July 2014 to December 2014, on a total of 559 blood donors referred to the Tehran blood transfusion center. The serum samples were tested for antibodies to HAV and HEV, using the enzyme-linked immunosorbent assay. Results: In the present study, 536 (95.9) cases were male and 23 (4.1) female with mean age of 38 years. Out of 559 blood donors, 107 (19.1) were first-time donors, 163 (29.2) lapsed donors and 289 (51.7) regular donors. Anti-HAV was found in 395 (70.7) and anti-HEV in 45 (8.1) of the blood donors. The HAV and HEV seroprevalence increased by age. There was no significant difference between genders in terms of anti-HAV and anti-HEV status. The HAV and HEV seroprevalence was significantly related to the level of education, where the donors with higher level of education had lower rate of HAV and HEV seroprevalence. The HAV and HEV seroprevalence was significantly higher in regular and lapsed donors than in first-time donors. Conclusions: The present study showed that both HAV and HEV infections are still endemic in Iran. © 2016, Kowsar Corp

    Efficiency comparison of alum and ferric chloride coagulants in removal of dye and organic material from industrial wastewater - A case study

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    Coagulation and flocculation are most widely methods used for dye and pollution removal from various wastewaters. The aim of this study is efficiency comparison of inorganic coagulant (Alum and Ferric Cchloride) for treatment of textile factory wastewater. The appropriate coagulant was selected at optimum condition for treatment of textile's factory wastewater by measuring of dye, COD, BOD5 and TSS parameters. The different pH (4, 5, 6, 7, 8 and 9) was used for determine the optimum pH. Totally, 240 samples were collected and exanimated according the standard methods of wastewater and water tests. Results showed that the ferric chloride has more removal efficiency than alum in removal of COD, TSS and dye. The most removal of COD, TSS and dye using alum was obtained 36, 19 and 68.8 while for ferric chloride was obtained 72, 60 and 98 respectively. The optimum pH 7 and 5 were obtained for alum and ferric chloride respectively. Based on the results, it can be concluded that COD, TSS and dye removal using ferric chloride has higher efficiency than alum. Therefore, application of ferric chloride in the same conditions is preferred than alum. © 2015 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria

    Response surface methodology (RSM) and its application for optimization of ammonium ions removal from aqueous solutions by pumice as a natural and low cost adsorbent

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    This research was conducted to study the adsorption of ammonium ions onto pumice as a natural and low-cost adsorbent. The physico-chemical properties of the pumice granular were characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Modeling and optimization of a NH4 + sorption process was accomplished by varying four independent parameters (pumice dosage, initial ammonium ion concentration, mixing rate and contact time) using a central composite design (CCD) under response surface methodology (RSM). The optimum conditions for maximum removal of NH4 + (70.3) were found to be 100 g, 20 mg/l, 300 rpm and 180 min, for pumice dosage, initial NH4 + ion concentration, mixing rate and contact time. It was found that the NH4 + adsorption on the pumice granular was dependent on adsorbent dosage and initial ammonium ion concentration. NH4 + was increased due to decrease the initial concentration of NH4 and increase the contact time, mixing rate and amount of adsorbent. © 2016 Archives of Environmental Protection

    Modifying the multicast tree in AMTree protocol using random core selection

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    One of two approaches used to construct the tree in multicast protocols, either shortest path tree approach, or core based tree approach. In AMTree protocol, the shortest path tree approach is used with incorporation of the idea of core from core based tree approach. In this paper we propose a new technique for constructing the multicast tree using pre-selected nodes to act as cores. The idea of the proposed technique is to reduce the optimization time and the number of nodes invoking for optimization. The experiments show that the number of nodes asking for optimization process is minimized and the optimization time is reduced too. Furthermore, tree efficiency for AMTree using the proposed technique is better than that of AMTree without it

    Comparing ovarian radiation doses in flat-panel and conventional angiography during uterine artery embolization: A randomized clinical trial

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    Background: Uterine artery embolization (UAE) is a minimally invasive procedure performed under fluoroscopy for the treatment of uterine fibroids and accompanied by radiation exposure. Objectives: To compare ovarian radiation doses during uterine artery embolization (UAE) in patients using conventional digital subtraction angiography (DSA) with those using digital flat-panel technology. Patients and Methods: Thirty women who were candidates for UAE were randomly enrolled for one of the two angiographic systems. Ovarian doses were calculated according to in-vitro phantom study results using entrance and exit doses and were compared between the two groups. Results: The mean right entrance dose was 1586±1221 mGy in the conventional and 522.3±400.1 mGy in the flat panel group (P=0.005). These figures were 1470±1170 mGy and 456±396 mGy, respectively for the left side (P=0.006). The mean right exit dose was 18.8±12.3 for the conventional and 9.4±6.4 mGy for the flat panel group (P=0.013). These figures were 16.7±11.3 and 10.2±7.2 mGy, respectively for the left side (P=0.06). The mean right ovarian dose was 139.9±92 in the conventional and 23.6±16.2 mGy in the flat panel group (P<0.0001). These figures were 101.7±77.6 and 24.6±16.9 mGy, respectively for the left side (P=0.002). Conclusion: Flat panel system can significantly reduce the ovarian radiation dose during UAE compared with conventional DSA. © 2013, Tehran University of Medical Sciences and Iranian Society of Radiology; Licensee KowsarKowsar Ltd

    Mandibular Fractures Admitted to the Emergency Department: Data Analysis from a Swiss Level One Trauma Centre

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    Mandibular fracture is a common occurrence in emergency medicine and belongs to the most frequent facial fractures. Historically road traffic injuries (RTIs) have played a prominent role as a cause for mandibular fractures. We extracted data from all patients between August 2012 and February 2015 with &quot;lower jaw fracture&quot; or &quot;mandibular fracture&quot; from the routine database from the emergency department. We conducted a descriptive analysis at a Swiss level one trauma centre. 144 patients were admitted with suspected mandibular fractures. The majority underwent CT diagnostic (83%). In 7% suspected mandibular fracture was not confirmed. More than half of all patients suffered two or more fractures. The fractures were median or paramedian in 77/144 patients (53%) and in other parts (corpus, mandibular angle, ramus mandibularis, collum, and temporomandibular joint) in 100/144 (69%). Male to female ratio was 3 : 1 up to 59 years of age; 69% were younger than 40 years. 72% of all patients presented during daytime, 69% had to be hospitalized, and 31% could be discharged from the ED after treatment. Most fractures were due to fall (44%), followed by interpersonal violence (25%) and sport activities (12%). Falls were a dominant cause of fracture in all age groups while violence and sport activities were common only in younger patients. Comparisons to other studies were difficult due to lack of standardization of causes contributing to the injuries. In the observed time period and setting RTIs have played a minor role compared to falls, interpersonal violence, and sports. In the future, standardized documentation as well as categorization of causes for analytic purposes is urgently needed to facilitate international comparison of studies
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