20 research outputs found

    Proposing a rigorous empirical model for estimating the bubble point pressure in heterogeneous carbonate reservoirs

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     Bubble point pressure is of great significance in reservoir engineering calculations affecting the success of reservoir simulation. For determining this valuable parameter, experimental tests are the most reliable techniques; however, these measurements are costly and time-consuming. So, it is crucial to propose an empirical model for estimating bubble point pressure. The existing correlations mainly have large errors and develop based on restricted database from a specific geographical location. As a result, development of an all-inclusive correlation is essential. In current article, gene expression programming (GEP) was used to create a generalized model for bubble point pressure estimation. To do this, an all-inclusive source of data was utilized for training and testing the model from the petroleum industry. Several statistical approaches including both illustration tools and diverse error functions were utilized to show the supremacy of the developed GEP model. Consequently, the recommended model is the most accurate as compared to the similar correlations in literature with the average absolute relative error (AARE = 11.41%) and determination coefficient (R2 = 0.96). Furthermore, the solution gas-oil ratio shows to be the most influencing variable on determining bubble point pressure according to sensitivity analysis. The results of contour map analysis demonstrate that most portions of the experimental region are predicted via the GEP equation with fewer errors as compared to two well-known literature correlations. Finally, the proposed GEP model can be of high prominence for accurate bubble point pressure estimation.Cited as: Rostami, A., Daneshi, A., Miri, R. Proposing a rigorous empirical model for estimating the bubble point pressure in heterogeneous carbonate reservoirs. Advances in Geo-Energy Research, 2020, 4(2): 126-134, doi: 10.26804/ager.2020.02.0

    Contamination with Organophosphate Toxins in Humans in Iran: A Systematic Review

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    Background: Organophosphate toxins are among chemical toxins that are dangerous for human health. Due to the increasing use of organophosphate compounds in a variety of products such as insecticides and pesticides, as well as easy access to these compounds, a systematic review on the related studies taken place in Iran seemed to be necessary. Methods: In this review, databases including Iranmedex, Medline, PubMed, Google Scholar and SID were searched for phrases related to organophosphates in both English and Farsi languages and up to April 2013. Only studies which had measured human contamination to these compounds in Iran were included. Results: Totally, 19 articles were found of which 10 articles met the inclusion criteria. According to these studies, organophosphate poisoning mainly happened due to occupational exposure in workers, inadvertently in children, and for suicide purposes in some reports. Conclusion: It seems that a high percentage of poisonings and deaths from these substances is due to lack of consumer awareness awareness about these chemicals and their complications. Therefore, in order to prevent poisoning it is necessary to educate families and related workers

    Accuracy of pixel-based classification: application of different algorithms to landscapes of Western Iran.

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    peer reviewedScenarios for monitoring land cover on a large scale, involving large volumes of data, are becoming more prevalent in remote sensing applications. The accuracy of algorithms is important for environmental monitoring and assessments. Because they performed equally well throughout the various research regions and required little human involvement during the categorization process, they appear to be resilient and accurate for automated, big area change monitoring. Malekshahi City is one of the important and at the same time critical areas in terms of land use change and forest area reduction in Ilam Province. Therefore, this study aimed to compare the accuracy of nine different methods for identifying land use types in Malekshahi City located in Western Iran. Results revealed that the artificial neural network (ANN) algorithm with back-propagation algorithms could reach the highest accuracy and efficiency among the other methods with kappa coefficient and overall accuracy of approximately 0.94 and 96.5, respectively. Then, with an overall accuracy of about 91.35 and 90.0, respectively, the methods of Mahalanobis distance (MD) and minimum distance to mean (MDM) were introduced as the next priority to categorize land use. Further investigation of the classified land use showed that good results can be provided about the area of the land use classes of the region by applying the ANN algorithm due to high accuracy. According to those results, it can be concluded that this method is the best algorithm to extract land use maps in Malekshahi City because of high accuracy

    Effect of 15% carbamide peroxide bleaching gel on color stability of giomer and microfilled composite resin: an in vitro comparison

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    Objectives: The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study. Study design: Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces. Then a spectrophotometer was used to measure L* (lightness), a* (redness, greenness) and b* (blueness, yellowness) color coordinates of all the discs. Subsequently, the specimens were subjected to 15% carbamide peroxide bleaching gel. After measuring the color coordinates once again, color changes (DE*) were calculated by the CIELAB system. Six specimens from each material (three specimens before bleaching agent application and three specimens thereafter) were viewed under an atomic force microscope (AFM) for surface topography evaluation. Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests at a=0.05. Results: There were no statistically significant differences in color changes (DE*) between the two materials (P>0.05). In addition, no significant differences were detected in surface roughness between composite resin and giomer discs before and after bleaching (P>0.05 for both). However, in both materials the differences in surface roughness were significant before and after bleaching procedures (P<0.001). Conclusions: Based on the results of the present study it was concluded that 15% carbamide peroxide does not induce clinically detectable color changes in composite resin and giomer despite an increase in surface roughness

    The monetary facilities payment for ecosystem services as an approach to restore the Degraded Urmia Lake in Iran.

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    peer reviewedThis study analyzed the potential use of Payment for Ecosystem Services (PES) as a strategy for improving water supply management. This study focused on the Siminehroud Sub-basin due to its high importance to the Basin of Urmia Lake (UL). Siminehroud is the second provider of water (by volume) to Urmia Lake. To evaluate the technical and economic feasibility of a PES scheme, the current land use map was extracted using satellite imagery. In addition, the two algorithms of Support Vector Machines (SVMs) and Maximum Likelihood (ML) are used for Landsat images classification, rather than analyzing the relationship between land use and ecosystem services. Then, the most relevant ecosystem services provided in the region were evaluated using the Benefit Transfer Method. In the last step, by designing and implementing a survey, on the one hand, the local farmers' Willingness to Accept (WTA) cash payments for reducing the area they cultivate, and on the other hand, the farmers' Willingness to Pay (WTP) for managing the water consumption were determined. The results illustrated that the WTA program is more acceptable among the beneficiaries. It is also notable that this program needs very high governmental funding. Furthermore, the results of the program indicate that the land area out of the cultivation cycle will gradually increase while the price of agricultural water will also increase

    Low Anterior and Very Low Anterior Resection in Patients with Rectal Cancer with or without Diverting Colostomy: A Comparison

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    Introduction: In colorectal cancer surgery, diverting colostomy after low anterior resection (LAR) and very low anterior resection (VLAR) operations is an issue of great significance to the surgeons. This study set out to compare the results of operation in patients with rectal cancer, undergoing VLAR and a type of LAR of the rectum, with or without diverting colostomy. Materials and Methods: 100 patients with rectal cancer undergoing VLAR and LAR, with or without diverting colostomy at a tertiary care hospital (Imam-Hossein Medical Center) were prospectively assessed from March, 2011 to February, 2015. Demographic data, radiotherapy history, and surgery-related data such as duration as well as post-operative complications were collected and analyzed. Results: Of 100 patients, 50 underwent VLAR or LAR without diverting colostomy, and 50 underwent surgical resection with diversion. The age, male to female ratio, and history of radiation were not different in the two groups (P&gt;0.05). The surgery was successful for 47 (94%) patients without diverting colostomy and for 48 patients (96%) with diverting colostomy. The age, gender, history of radiotherapy, and surgery duration did not affect the surgery success rate (P &gt; 0.05), which is fairly significant. The two groups showed no significant difference in surgical outcomes and complications (P &gt; 0.05). Conclusion: Contrary to popular belief, the surgery success rate and complications were not significantly different in the group without diverting colostomy and the group with diverting colostomy. VLAR and LAR without diverting colostomy are recommended. &nbsp

    Resilience and anxiety in nurses in a hospital in Iran during the COVID-19 pandemic: a cross-sectional study

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    The lack of any definitive treatment or prevention of COVID-19 disease has created a lot of stress and anxiety in societies. This study aimed to evaluate the resilience and anxiety of COVID-19 in nurses of Imam Khomeini Hospital in Jiroft and their relationship with demographic variables from April to August 2020. The present study is descriptive-analytical and cross-sectional. To select the statistical sample, the census method was used so that 80 nurses working in different wards of the hospital were selected and included in the study. The resilience measurement tool is the Connor-Davidson Resilience Questionnaire (CD-RIS). COVID-19 anxiety was assessed using a comprehensive national questionnaire. Data were analyzed using descriptive and analytical statistics Chi-square, Independent two-sample parametric t-test, and ANOVA through SPSS 20. The level of COVID-19 anxiety in nurses was moderate (19.3±11.64) and the rate of resilience was low (36.7±16.65). There is a statistically significant difference between resilience in nurses and age (p = 0.003). There was no statistically significant relationship between the rate of resilience in nurses and gender (p = 0.13), the unit of service (p = 0.87), marital status (p = 0.98), work experience (p = 0.06), and the level of education (p = 0.63). There was no statistically significant relationship between anxiety in nurses and age (p = 0.53), gender (p = 0.59), the unit of work (p = 0.48), marital status (p = 0.90), work experience (p = 0.40), and level of education (p = 0.60). The results of multivariate analysis showed that, work experience, and place of work have a statistically significant relationship with resilience and anxiety of COVID-19 in nurses, respectively (p <0.05).The level of COVID-19 anxiety in nurses is moderate and the rate of resilience is high. Given the current high-risk situation, it is important to identify nurses prone to psychological disorders to maintain and improve their mental health with appropriate strategies and techniques

    Investigation of Views and Experiences of Medical Interns on the Facilitating and Inhibiting Factors Affecting the Quality of Education in the Clinical Education System

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    Introduction: Clinical education is the most important part of medical education that provides a golden opportunity for medical students to combine their theoretical mix with the clinical environment, and this is important in the countries of the style of the arena of medicine Special attention is paid. Therefore, this study was conducted to examine the views and experiences of medical students as facilitators and inhibitors of clinical education quality. Methods: This is qualitative research and a phenomenological approach was used. The study population consisted of medical students of Kerman University of Medical Sciences. Target-based sampling was performed on 40 medical students. The method for collecting information was a deep interview with the participants. The data were analyzed by the Colaizzi method. Results: Two initial codes were extracted in the form of two main themes (facilitating and inhibiting factors) and 10 sub-themes including providing motivational patterns and creating interest in interns, the high scientific and educational level of attending professors, use of technology, authorizing more responsibility, inappropriate treatment, inappropriate educational planning, inappropriate evaluation method, low-quality mornings, lack of facilities, and overwhelming of some wards were classified. Conclusion: Considering these factors, it is possible to raise the quality of clinical education to the highest possible level and educate responsible and responsible physicians for generations

    Modelling the impacts of climate and land use change on water security in a semi-arid forested watershed using InVEST

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    Water security, a key policy objective for sustainable development, is under stress as a result of land use and climate change, especially in (semi-)arid areas like Iran. Land use change alters surface runoff and affects basin-wide hydrological processes and water consumption, while climate change modifies precipitation and temperature patterns and consequently evapotranspiration and water supply. In this study, water yield, supply and consumption are simulated in a watershed draining into the Caspian Sea in northern Iran, using the water yield model in the Integrated Valuation of Environmental Service and Tradeoffs (InVEST) tool. The novelty of this study is found in the combined modelling of the impacts of climate and land use change scenarios on water security, translating these results into a water stress indicator, and estimating the associated economic costs of reduced future water supply. The results show substantial spatial variation of the negative impacts of water supply and future water security across the watershed, further increasing the pressure on its inhabitants, their economic activities and ecological values. The estimation of the economic costs of increased water insecurity allows us to inform policy and decision-makers about future investments in climate adaptation and mitigation
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