3,155 research outputs found

    Transparency effect in the emergence of monopolies in social networks

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    Power law degree distribution was shown in many complex networks. However, in most real systems, deviation from power-law behavior is observed in social and economical networks and emergence of giant hubs is obvious in real network structures far from the tail of power law. We propose a model based on the information transparency (transparency means how much the information is obvious to others). This model can explain power structure in societies with non-transparency in information delivery. The emergence of ultra powerful nodes is explained as a direct result of censorship. Based on these assumptions, we define four distinct transparency regions: perfect non-transparent, low transparent, perfect transparent and exaggerated regions. We observe the emergence of some ultra powerful (very high degree) nodes in low transparent networks, in accordance with the economical and social systems. We show that the low transparent networks are more vulnerable to attacks and the controllability of low transparent networks is harder than the others. Also, the ultra powerful nodes in the low transparent networks have a smaller mean length and higher clustering coefficients than the other regions.Comment: 14 Pages, 3 figure

    Actinomycosis may be presented in unusual organs: A report of two cases

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    Actinomycosis is a chronic granulomatous suppurative disease characterized by direct extension to the contagious tissue with the formation of multiple drainage sinus tracts through which tiny colonies of organisms called sulfur granules are discharged. Here, we report 2 cases of actinomycosis from Iran. One of them had actinomycosis on the hand and the other on the foot. Samples of tissue biopsy showed sulfur granules associated with colonies of actinomyces, thus confirming the diagnosis in both cases. The response to curettage and penicillin therapy was satisfactory in our patients. The chronic and indolent course of actinomycosis resembles tuberculosis, fungal infection and malignancy. So, increasing awareness among the clinicians and clinical microbiologists will help in the early diagnosis of the disease and in the initiation of early and proper treatment

    Three-Dimensional Vapor Intrusion Modeling Approach that Combines Wind and Stack Effects on Indoor, Atmospheric, and Subsurface Domains

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    Vapor intrusion (IV) exposure risks are difficult to characterize due to the role of atmospheric, building and subsurface processes. This study presents a three-dimensional VI model that extends the common subsurface fate and transport equations to incorporate wind and stack effects on indoor air pressure, building air exchange rate (AER) and indoor contaminant concentration to improve VI exposure risk estimates. The model incorporates three modeling programs: (1) COMSOL Multiphysics to model subsurface fate and transport processes, (2) CFD0 to model atmospheric air flow around the building, and (3) CONTAM to model indoor air quality. The combined VI model predicts AER values, zonal indoor air pressures and zonal indoor air contaminant concentrations as a function of wind speed, wind direction and outdoor and indoor temperature. Steady state modeling results for a single-story building with a basement demonstrate that wind speed, wind direction and opening locations in a building play important roles in changing the AER, indoor air pressure, and indoor air contaminant concentration. Calculated indoor air pressures ranged from approximately −10 Pa to +4 Pa depending on weather conditions and building characteristics. AER values, mass entry rates and indoor air concentrations vary depending on weather conditions and building characteristics. The presented modeling approach can be used to investigate the relationship between building features, AER, building pressures, soil gas concentrations, indoor air concentrations and VI exposure risks

    Effects of information technology on the business

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    Information Technology develops extremely fast and never stops moving because we need this important and strategic technology. The article is about effects of Information Technology on Business and help of IT to prevent products smuggling, and in this scientific article we tried to introduce big achievements which are ideal prevention and security solutions that IT delivered recently and it had a very big effect of Business World.В современном мире, информатизация, как процесс, затрагивает все сферы деятельности государства как единой системы. Особо важно иметь весь срез данных при стратегическом планировании любого уровня, которое является одной из составляющих управленческой деятельности. В сфере большого, среднего и малого бизнеса информационные технологии переводят деятельность предприятий на качественно иной уровень. В статье рассматриваются вопросы, связанные с применением информационных технологий для предотвращения проникновения на рынок контрафактной продукции

    US Residential Building Air Exchange Rates: New Perspectives to Improve Decision Making at Vapor Intrusion Sites

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    Vapor intrusion (VI) is well-known to be difficult to characterize because indoor air (IA) concentrations exhibit considerable temporal and spatial variability in homes throughout impacted communities. To overcome this and other limitations, most VI science has focused on subsurface processes; however there is a need to understand the role of aboveground processes, especially building operation, in the context of VI exposure risks. This tutorial review focuses on building air exchange rates (AERs) and provides a review of literature related building AERs to inform decision making at VI sites. Commonly referenced AER values used by VI regulators and practitioners do not account for the variability in AER values that have been published in indoor air quality studies. The information presented herein highlights that seasonal differences, short-term weather conditions, home age and air conditioning status, which are well known to influence AERs, are also likely to influence IA concentrations at VI sites. Results of a 3D VI model in combination with relevant AER values reveal that IA concentrations can vary more than one order of magnitude due to air conditioning status and one order of magnitude due to house age. Collectively, the data presented strongly support the need to consider AERs when making decisions at VI sites

    Generation of pcdna 3.1+-gh as a recombinant expression vector of ostrich growth hormone cdna in saccharomyces cerevisiae

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    Growth hormone is essential hormone for vertebrates like the ostrich (Struthio camelus) for growth stimulation, carbohydrate metabolism, protein assimilation etc. Growth hormone is secreted by the pituitary gland and expressed in many cells and tissues. The purpose of this study was generation of pcDNA 3.1+-GH recombinant expression vector in order to sub-clone ostrich growth hormone cDNA into Escherichia coli. In brief, total RNA was extracted from the pituitary gland tissue and cDNA sample was synthesised. The cDNA was amplified by PCR and revealed a 672 bp fragment on 2% agarose gel electrophoresis. Then, the ostrich growth hormone cDNA was extracted from the gel and was cloned into pCR8/GW/TOPO vector by T/A cloning technique to produce pCR8/GW/TOPO-GH. After obtaining the sequence of cDNA of the ostrich in Iran, it was submitted in GenBank (Accession number: JN559394). Finally, the GH cDNA was sub-cloned using pcDNA 3.1+ into Saccharomyces cerevisiae and pcDNA 3.1+-GH recombinant expression vector was generated. The results of present study were showed that ostrich growth hormone cDNA was successfully sub-cloned into Saccharomyces cerevisiae. Therefore, the pcDNA 3.1+-GH recombinant expression vector generated in this study could be useful to express the ostrich growth hormone in yeast cells as a simple and affordable way to produce this hormone at a large scale

    Diode calibration for dose determination in total body irradiation

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    Background: Total Body Irradiation (TBI) is different from standard radiotherapy in many aspects, so it is not easy to predict the delivered dose to the patient under TBI treatment. Diode dosimetry procedures for surface dose reading can help to define variations of the actually delivered dose from the prescribed one. The aim of this study was to describe the measurements made to calibrate diodes in order to implement as a dosimeter for TBI tratment. An algorithm was also proposed based on diode dosimetry in order to determine the midplane dose. Materials and Methods: In this study, four p-type diodes connected to a MULTIDOSE electrometer were implemented as dosimeter. For diode calibration a water phantom with dimension of 30�30�32cm3 along with a 0.6 cc Farmer ion chamber were used. Directional dependence of diodes, the effects of thickness correction factor and complete backscatter factor were studied. Three algorithms, arithmetic, geometric mean and proposed algorithm were used to investigate midplane dose determination in TBI condition. Results: It was found by measurements that the effect of angle incident on diode response was significant and should have been taken into account. Variation in thickness correction factor was found about 0.7. The accuracy in midplane dose determination in the arithmetic, geometric mean and proposed algorithm was about 3.8, 12.5 and 3.3, respectively. Conclusion: Diode dosimetry is very useful as a check of midplane dose delivered to patients under TBI treatment. When the calibration and correction factors are carefully determined, high precision can be obtained. The proposed algorithm by this study seems to be useful in order to midplane dose determination in TBI condition
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