696 research outputs found
Magnetic deflections of ultra-high energy cosmic rays from Centaurus A
The origin and mass composition of ultra-high energy cosmic rays (UHECRs) are among the mysteries of particle astrophysics. Since UHECRs are mostly or entirely charged particles, they will be deflected in cosmic magnetic fields on their way to Earth. UHECR deflections in the Galactic magnetic fields (GMF) should be considered to identify their origin and nature.
The calculated Galactic magnetic deflections of UHECRs from a source strongly depend on the GMF model. I use the recent GMF model of Jansson and Farrar (JF12), a 35-parameter model which includes coherent, striated and random components and is constrained by WMAP7 Galactic synchrotron emission map and more than forty thousand extragalactic rotation measures. I develop a new method of implementing a random field using a Kolmogorov spectrum and scale it with the JF12 random component strengths.
Simulated UHECRs are propagated through the GMF using the publicly available propagation code CRT. These particles are simulated from Centaurus A, which is the nearest AGN to Earth. I identify the expected arrival direction loci of UHECRs in the JF12 GMF model for different rigidities (energy divided by charge) between 2 and 100 EV (1 EV ≡ 1018 V) to determine whether Centaurus A could be a significant source of the UHECR excess reported by Pierre Auger Observatory. I calculate the excess of event arrival directions, with respect to isotropic expectations, for cases of pure protons, pure iron, and a mixture.
I also develop a method for identifying the mass composition of UHECRs under specific source and GMF hypotheses. Comparing Auger observations with simulations of different rigidities leads to the identification of the charges of the events. Consistent simulated rigidities are found for each Auger event based on their overlap probabilities. The charge of each event is the measured energy divided by the rigidity of the most consistent simulation.
Including a Kolmogorov random field component to the JF12 regular component does not significantly change the results of propagation at high rigidities whereas at low rigidities it smears the arrival distributions of events to such an extent that deflection studies can become difficult
Pharmacological effect of Actiumlappa: A review study
Actium lappa in the sunflower family, is a biennial plant, rather tall, reaching as much as 3 cultivated in gardens forits root used as a vegetable native This species is native to the temperate regions of the old world. It has large, alternating, cordiform leaves that have a long petiole and are pubescent on the underside. The aim of this study wasto overview its therapeutic effects of this plant. This review article was carried out by searching studies in PubMed, Medline, Web of Science, and IranMedex databases. The initial search strategy identified about 58 references. Inthis study, 27 studies was accepted for further screening and met all our inclusion criteria [in English, full text, therapeutic effects of Actium lappa and dated mainly from the year 1996 to 2016.The search terms were "Actiumlappa", "therapeutic properties", "pharmacological effects". It is commonly used for its antioxidants andantidiabetic, anti-inflammatory effects, anti-cancers, anti-allergic effect, anti-ulcer effect, antitubercular activity, anti-acne, anti-dermal fibroblast, anti-sterility, anti-ulcerogenic, ulcerative colitis, angiostrongyliasis effect, gastroprotective activity, hepatoprotective effects, anti-aging effect, anti-austeric activity, cytotoxicity effect. Different medicinal properties of this plantrequire more studies regarding to other unknown properties of thisvaluable plant
Positive predictive value of 16-Row CT angiography as compared with conventional invasive angiography
In this work authors have evaluated the positive predictive value of 16-multidetector-row CT angiography (CTA) in comparison with conventional invasive angiography (CIA) in the diagnosis of significant stenosis. For this purpose, 8 patients suspected to significant stenosis was investigated. These patients were undertaken CIA procedure after CTA. Result of this study reveals that for patient-base analysis, the positive predictive value of CTA was 87.5. The findings of this study reveal that CT angiography with 16-slice scanner might be considered as an acceptable technique for rapid triage of patients. High values of PPV reveal a moderate performance of CTA. However, due to low number of patients,the obtained results cannot be used for final decision
Evaluation of Negative Predictive Value (NPV) of 16-Row CT angiography in comparison with conventional angiography
Negative predictive value (NPV) is one of the important indicatives for evaluating a medical procedure. Herein, we have evaluated the NPV of 16-multidetector-row CT angiography (CTA) in comparison with conventional invasive angiography (CIA) in the diagnosis of significant stenosis. In this regard, 8 patients suspected to stenosis were investigated. They patients were undertaken CIA procedure after CTA. The obtained results show, the NPV of 50 for patient-base analysis. The findings of this study reveal that CT angiography with 16-slice scanner might be considered as an acceptable technique for rapid triage of patients. Low values of NPV reveal a moderate performance of CTA. However, due to low number of patients, the obtained results cannot be used for final decision. Hence, more is required to improve and achieve reliable results
Evaluation of specificity of CT angiography compared to conventional angiography for 16-Row Scanner
Herein, authors have evaluated the specificity of CT angiography (CTA) in comparison with conventional invasive angiography (CIA) in the diagnosis of coronary stenosis. For this purpose, 8 patients suspected to stenosis was used. They were undertaken CIA procedure after CTA using 16-multidetector-row machine. Result reveals that for patient-base analysis, the specificity of CTA was 25. The values of specificity reveal a unacceptable performance of CTA. However, due to low number of patients, the obtained results cannot be used for final decision
Social sustainability of compact neighbourhoods: Evidence from London and Berlin
This article revisits social sustainability of compact urban neighbourhoods based on first-hand evidence from four case studies in London and Berlin. It suggests a working definition for socially sustainable neighbourhoods, develops a tripartite integrative evaluation framework for measuring social sustainability of urban neighbourhoods, and applies it to four case studies in London and Berlin. Findings of this research are in line with some dominant arguments made in favour of social sustainability of compact urban form, but challenges some others. Research findings suggest that compact urban form is not an urban orthodoxy, but has multiple and contrasting social meanings and perceptions in different contexts and places
Removal of m-xylene from water by impregnated activated carbon
Volatile organic compounds (VOCs) are the main matters which can pollute water therefore, must be controlled under increasingly stringent environmental regulations.This work analyses the adsorption of impregnated active carbons prepared with oak bark to remove m-xylene from aqueous solutions. When the impregnation step is performed on the raw material then carbonizations of activated carbon was carried out. Not expensive raw material and chemical agent were used as active species where used for preparing the appropriate adsorbent for removal of m-xylene from water. In this work the effect of adsorption temperature, pH and the initial concentration of process were investigated. It is clear that with increasing the initial concentration the removal efficiency of adsorption will be increased. The effect of temperature was studied by increasing the temperature from 20 to 60 °C. with increasing the temperature the removal efficiency will be increased in the range of 20-60 °C
Investigation of the physical abrasion of rubber polymer reinforced with nanoparticles used in fabrication of medical devices
With recent development in nanotechnology, nanocomposite materials have become of the most important polymeric materials which exhibit excellent biological, physical, chemical and thermal properties. Rubber based nanocomposites is one of the mast interesting field in the literatures and material science. In this paper preparation and characterization of rubber/ resin with nano iron oxide has been done. Two roll mills method have been used for mixing compounds. This route of mixing has been attracted in recent years especially for rubber and resin based nanocomposites. Effect of nano iron oxide on the abrasion properties of compounds has been investigated. The results show that with addition of nano iron oxide to acrylonitrile butadiene rubber/resin matrix, abrasion content of compounds has been decreased. Moreover the scanning electron microscopy and optical microscopy images have been used for better recognition of abrasion manner of compounds
A Survey on Supply Side of Mines: a Case Study of Iran
The mining sector is one of the most important factors in so many countries like Iran to achieve sustainable development. Due to importance of this sector in Iran, this paper investigates the supply side of mines in Iran. Hence, the main objective of this study is to investigate the supply side of mining in Iran. In order to get this aim, first, the annual time series data are collected from the website of Central Bank and Statistics Center of Iran. This paper determines the elasticity of the production factors of labor and capital for mining sector in Iran covering data 1988 to 2010. The Cobb-Douglas function is used to estimate mining sector production function which involves the OLS method using the EVIEWS8 and SPSS software. According to the results of this study during the years of the study the coefficients of the natural logarithm of the real capital and the natural logarithm of the labor in Iran are 1.621488 and 2.962340, respectively and these coefficients are statistically significant at the 5% confidence level. Indeed, these coefficients show the amount of elasticity of production factors for the mining sector in Iran. Hence, if the capital in the mining sector increases one percentage then the production in this sector increases 1.621488 and while the labor in this sector increases one percentage, then the production in this sector increases 2.962340 percent
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