294 research outputs found

    Simulating urban growth by emphasis on connective routes network (case study: Bojnourd city)

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    AbstractDevelopment of urban construction and ever-increasing growth of population lead to landuse changes especially in agricultural lands, which play an important role in providing human food. According to this issue, a proper landuse planning is required to protecting and preserving the valuable agricultural lands and environment, in today’s world. The prediction of urban growth can help in understanding the potential impacts on a region’s water resource, economy and people. One of the effective parameters in development of cities is connective routes network and their different types and qualities that play an important role in decreasing or increasing the growth of the city. On the other hand, the type of the connective routes network is an important factor for the speed and quality of development. In this paper, two different scenarios were used to simulate landuse changes and analyzing their results. In first scenario, modeling is based on the effective parameters in urban growth without classification of connective routes network. In the second scenario, effective parameters in urban growth were considered and connective routes were classified in 6 different classes with different weights in order to examine their effect on urban development. Simulation of landuse has been carried out for 2020–2050. The results clearly showed the effect of the connective routes network classification in output maps so that the effect of the first and second main routes network in development, is conspicuous

    Measurement and Comparison of Mercury Concentration in Different Length Groups of Common Carp Muscle Tissue from the Shadegan Wetland

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    Background: Due to the ecological importance of the Shadegan wetland as a valuable international wetland and some studies reporting high mercury concentration in its water and birds' tissues, this study was done to measure and compare the concentration of accumulated mercury in different length groups of common carp muscle tissue and to determine the correlation of mercury concentration with morphological parameters such as standard length, total length and total weight. Methods: In this cross-sectional study, 41 common carp fish were randomly captured in summer 2011 from the Shadegan wetland, and they were classified into three groups based on their lengths. Samples were prepared from their muscle tissues and mercury concentration was determined by Advanced Mercury Analyzer. The relation between mercury concentration in the samples and demographic characteristics was determined by Pearson’s Correlation Coefficient. Results: Mean (±Standard deviation) mercury concentration in groups of A, B and C were respectively 0.337±0.15, 0.556±0.21 and 0.798±0.19 µg gr-1 of dry weight basis. Comparison of mercury concentrations of muscle tissues among the three groups showed statistically significant difference (P=0.001); so that, mercury concentration was increased with increase of weight and length. Conclusion: Mercury concentration in fish weighing more than 500 grams were higher than the limit allowed by WHO and EPA, it is necessary to be more careful about consuming this fis

    Application of a New Designed ROADM to Improve the Performance of Elastic Optical Network

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    The quick rise of emerging technologies like spectrally efficient multicarrier with a higher order modulation and bandwidth variable wavelength selective switches have caused a shift of the optical network architecture from fixed to the flexible elastic optical network (EON), in terms of bit rate, center frequency spacing, modulation format, and optical reach. By using bandwidth-variable transceivers, colorless flexible-grid reconfigurable optical add-drop multiplexers (ROADM), as well as a choice of different optical source types, operators can provide a range of service types and improve network efficiency. Implementation of the EON network requires careful consideration, especially in terms of the ROADM structure to achieve optimal performance. We propose a low-cost ROADM structure with an order-based connection method that includes a high degree with a blocking probability of less than 10-4. Then, we applied the new design of ROADM in EON that transported 1 Tb/s. In the final step, we conclude that our system accommodated 20 percent more traffic demand over an average of the low-rate wavelength approach

    Profile of side Effects in Patients Receiving Blood Transfusion from the Perspective of Management Unit

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    Background: In spite of being vital to save the patients' life, blood transition may be dangerous and even fatal, too the aim of this study was to investigate the side effects (complications) of blood transfusion in the educational hospitals of Qazvin.Materials and Methods: This is a descriptive cross sectional and practical study that was carried out in 2010. In this study, all the patients of four  health training centers in Qazvin, that have had blood transfusion and complications, were considered as a part of the statistical community. The instrument for data collection was checklist which was filled through an interview with blood bank manager and some other responsible individuals and scrutinizing files of patients who had blood injection among the blood products consumption, request for the packed cells was the most and for fresh frozen plasma was the least.Results: 75% of these people had only one blood injection and the maximum injection volume was 100cc which was done mostly in the evening. Most of the transfusion history belonged to 21-30 year olds in our statistical community. 56% of all Patients that had transfusion, possessed background of some disease such as heart problems (21.9%). More than half of them (2.56%) had a chill feeling complication transfusion and there was a significant relationship between the blood transfusion volume and itching complication.Conclusion: Existence of a continuous association between blood transfusion organization and hospitals is indispensable. Therefore, it seems that Hemovigilance system or computer connected network to send reports, between hospital centers and blood transfusion organization of Iran, can be an appropriate solution

    Investigating the effect of entrepreneurial competencies on business performance among early stage entrepreneurs Global Entrepreneurship Monitor (GEM 2010 survey data)

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    Entrepreneurs of this era need to be more competent and skillful compared to businessmen working in the beginning of this century. A robust body of knowledge has grown around entrepreneurs' need for superior skills and personality characteristics; the ones that enables them to effectively compete and survive. In this study, we analyzed the relationship between entrepreneurial competencies along with social norms and entrepreneurs' business performance. Data of GEM gathered during 2010 was utilized and 125 cases was selected from 59 member countries. Confirmatory factor analysis showed that social image of entrepreneurs is a better measure than national attitude toward entrepreneurship for the construct "entrepreneurial social norms" based on their factor loadings. For the same reason, entrepreneurial skills remained as the measure of entrepreneurial competencies and entrepreneurial personality measure was dropped. And, for the dependent variable "performance", growth and innovation remained as a more powerful measures than export. Finally, the positive effect of entrepreneurial competencies on business performance was supported by the data and results revealed that there is a positive effect between entrepreneurial social norms on entrepreneurs' competencies which conforms the mediating role of entrepreneurial competencies. However, the data did not support the direct effect of entrepreneurial social norms on performance

    Role of \u3csup\u3e18\u3c/sup\u3eF-FDG PET Scan in Rheumatoid Lung Nodule: Case Report and Review of the Literature

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    Flourine-18 fluoro-2-deoxy-glucose (18F-FDG) positron emission tomography combined with computed tomography (PET/CT) is a useful test for the management of malignant conditions. Inflammatory and infectious processes, however, can cause increased uptake on PET scanning, often causing diagnostic dilemmas. This knowledge is important to the rheumatologist not only because of the inflammatory conditions we treat but also because certain rheumatic diseases impose an increased risk of malignancy either due to the disease itself or as a consequence of medications used to treat the rheumatic diseases. There is an increasing body of evidence investigating the role of PET scans in inflammatory conditions. This paper describes a patient with rheumatoid arthritis who developed pulmonary nodules that showed increased uptake on PET/CT scan and reviews the use of PET scanning in the diagnosis and management of rheumatoid arthritis

    The Effect of Contact Lens Induced Myopia and Hyperopia on Retinal Thickness and Volume Measured by Optical Coherence Tomography

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    Purpose:To determine the effect of induced myopia and hyperopia in emmetropic eyes using soft contact lenses on retinal parameters, measured by optical coherence tomography.Patients and Methods: In this quasi-experimental self-controlled study 57 emmetropic participants, 18 - 42 years of age, were studied. Each subject underwent a complete ophthalmic examinations including, measurement of best corrected visual acuity, intraocular pressure, dry and cycloplegic refractions, and axial length. Optical coherence tomography scans to measure foveal thickness, parafoveal thickness and perifoveal thickness were performed while different refraction powers were induced in each eye by wearing soft contact lenses of five different diopter (- 10.00, - 5.00, plano, + 5.00, + 10.00).Results: Fifty seven normal emmetropic participants with a mean age of 25.78 ± 6.50 years participated in the present study. Average foveal thickness was 246.02 ± 22.03 μm, 245.47 ± 22.78 μm, 246.47 ± 24.38 μm, 246.42 ± 22.96 μm, and 246.18 ± 22.46 μm in high-induced- myopic (CL: + 10.00 D), mild-induced-myopic (CL: + 5.00 D), emmetropic (CL: Plano), mild-induced-hyperopic (CL: - 5.00 D), and high-induced-hyperopic (CL: - 10.00 D) groups, respectively. Average parafoveal thickness was 329.21 ± 16.31 μm, 329.24 ± 16.36 μm, 328.86 ± 16.46 μm, 328.92 ± 16.57 μm, and 328.80 ± 16.76 μm in high-induced-myopic, mild-induced-myopic, emmetropic, mild-induced-hyperopic, and high-induced-hyperopic groups, respectively. Corresponding numbers for perifoveal thickness was 312.25 ± 14.39 μm, 311.84 ± 14.91 μm, 312.46 ± 16.55 μm, 311.57 ± 14.88 μm, and 311.77 ± 14.96 μm. Conclusion: Contact lens induced myopia and hyperopia had no significant effect on foveal thickness,parafovealthickness and perifoveal thickness readings in Fourier domain optical coherence tomography.Keywords: Optical coherence tomography; myopia; hyperopia; retinal parameters; contact lens.

    Comparative Evaluation of Ultraviolet and Visible Light Transmittance through Prescriptive Ophthalmic Minus Lenses

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    Background: Wearing spectacles is the most common approach in correcting the refractive errors worldwide. Due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. These lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission of ultraviolet rays. This study aims to compare the transmission of ultraviolet (A and B) and visible rays through coated and uncoated prescriptive ophthalmic plastic lenses.Materials and Methods: In this study, 39 minus non-photochromic multi-coated white plastic single-vision lenses; 9 similar lenses but without any coatings were assessed by spectral transmittancemeter for evaluation of the transmission of visible and ultraviolet rays.Results: The transmission of visible light was 97.9%±1.07% for coated lenses and 93.5%±0.54% for lenses without coating. Ultraviolet-A transmission was 12.15%±8.02% for coated lenses compared to 66.27%±23.92% in lenses without coating. The transmission of ultraviolet-B rays was 1.21%±0.4% and 23.0%±15.97% for lenses with and without coatings, respectively.Conclusion: The transmission of visible light was significantly higher in multi-coated lenses compared to uncoated samples; whereas the transmissions of ultraviolet rays in multi-coated lenses were significantly lower than uncoated ones. Therefore, it is recommended that, except for particular cases, prescribed lenses be equipped with this multi-layer coating

    Prevalence of Trypanosoma evansi in camels using molecular and parasitological methods in the southeast of Iran, 2011

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    Surra is caused by infection with the protozoal parasite, Trypanosoma evansi. This parasite was transmitted mechanically by biting flies which is widespread in camels in the world. The aim of this study is to determine the prevalence of T. evansi in camels in Rafsanjan, Kerman province, southeast of Iran. In this study, 95 suspected camels were randomly selected in 2011. Blood samples were taken from deep blood vessels. Thin and thick blood smears were prepared in laboratory. Blood smears were stained by Giemsa and studied under a light microscope. The positive blood samples were also used for further molecular analysis. Data were analyzed using SPSS 17.0 software and P B 0.05 was considered as statistical difference. A total of 95 camels were examined for infection with T.evansi using parasitological and molecular methods. The overall prevalence of infection was 2.1 %. It was found that the frequency of infection was significantly higher (P\ 0.05) in age group [6 years old than the corresponding younger camels. However, there was no significant difference when the gender was considered. PCR technique confirmed the two infected cases were T. evansi. Results of the present study indicated that surra is present in Rafsanjan county, Kerman province in an infection rate of 2.1 % in camels. To our knowledge, this is the first study reported from this province. Further investigations are needed to focus on vectors and to evaluate the risk factors
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