26 research outputs found

    Optimal PMU location in power systems using MICA

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    AbstractThis study presented a modified imperialist competitive algorithm (MICA) for optimal placement of phasor measurement units (PMUs) in normal and contingency conditions of power systems. The optimal PMU placement problem is used for full network observability with the minimum number of PMUs. For this purpose, PMUs are installed in strategic buses. Efficiency of the proposed method is shown by the simulation results of IEEE 14, 30, 57, and 118-bus test systems. Results of the numerical simulation on IEEE-test systems indicated that the proposed technique provided maximum redundancy measurement and minimum request of PMUs so that the whole system could be topologically observable by installing PMUs on the minimum system buses. To verify the proposed method, the results are compared with those of some recently reported methods. When MICA is used for solving optimal PMU placement (OPP), the number of PMUs would be usually equal to or less than those of the other existing methods. Results indicated that MICA is a very fast and accurate algorithm for OPP solution

    The effect of social determinants of health on quality of life among Afghan refugees in Iran during the COVID-19 pandemic:a path analysis

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    BACKGROUND: The COVID-19 pandemic has created significant challenges in 2020 in the world and Iran. To help vulnerable groups such as refugees during the response and recovery phases of the COVID-19 pandemic, identifying the quality of life (QOL) and its associated factors is helpful. Considering that research in this field is limited, this study evaluated the effect of social determinants of health on the quality of life among Afghan refugees in Iran during the COVID-19 pandemic. METHODS: We conducted a cross-sectional study on 300 Afghan refugees and migrants in Alborz province, Iran, from February to May 2022 using Convenience sampling. Data were completed using the socioeconomic status scale (SES), World Health Organization's quality of life -BREF (WHOQOL), Depression, Anxiety and Stress Scale—21 Items (DASS-21), and COVID-19 Post-Traumatic Stress Disorder Checklist (COVID-PTSD). In addition, path analysis was applied to evaluate the relationships among the research variables with quality of life. RESULTS: 64.3% of the study participants were male, with a mean of 29.29 ± 9.64 years. The path analysis showed that SES had the most positive relationship (B = .266), and the number of COVID-19 cases had the most negative relationship (B = -.169) with the quality of life from both paths. The self-rated health had the most positive relationship (B = .25), and the DASS score had the most negative relationship (B = -.2) with the quality of life through only one path. Access to medical services was the only variable that indirectly had a positive causal relationship with QOL (B = .044). CONCLUSION: We provided an empirical model that illustrates the relationships between quality of life and social determinants of health among Afghan refugees and migrants during the Covid19 pandemic. The negative emotional states of Depression, Anxiety, and Stress (DAS) as a mediator play an essential role in the quality of life and other variables

    Distinct neurocomputational mechanisms support informational and socially normative conformity

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    A change of mind in response to social influence could be driven by informational conformity to increase accuracy, or by normative conformity to comply with social norms such as reciprocity. Disentangling the behavioural, cognitive, and neurobiological underpinnings of informational and normative conformity have proven elusive. Here, participants underwent fMRI while performing a perceptual task that involved both advice-taking and advice-giving to human and computer partners. The concurrent inclusion of 2 different social roles and 2 different social partners revealed distinct behavioural and neural markers for informational and normative conformity. Dorsal anterior cingulate cortex (dACC) BOLD response tracked informational conformity towards both human and computer but tracked normative conformity only when interacting with humans. A network of brain areas (dorsomedial prefrontal cortex (dmPFC) and temporoparietal junction (TPJ)) that tracked normative conformity increased their functional coupling with the dACC when interacting with humans. These findings enable differentiating the neural mechanisms by which different types of conformity shape social changes of mind

    Performance Analysis Of Comercial Simulation-Based Optimization Packages: Optquest And Witness Optimizer

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    The objective of this study is to evaluate and compare two commercial simulation-based optimization packages, OptQuest and Witness Optimizer, to determine their relative performance based on the quality of obtained solutions in a reasonable computational effort. Two well-known benchmark problems, the pull manufacturing system and the inventory system, are used to evaluate and compare the performance of OptQuest and Witness Optimizer. Significant validation efforts are made to ensure that simulation models developed in Arena and Witness are identical. The experimental results indicate that both optimization packages have good performance on the given problems. Both packages found near-global optimal (or satisfactory) solutions in an acceptable computation time. © 2011 IEEE

    Clinical and Socio-Demographic Variables Associated With Long COVID-19:A Cross-Sectional Study

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    Considering the importance of long COVID-19 (LC), this study aimed to investigate the relationship between clinical/sociodemographic factors and LC symptoms (LCS). This online cross-sectional study was conducted on 308 people infected with COVID-19 in Alborz, Iran, from April 1 to June 1, 2022. Multivariable logistic regression models were applied to measure the association between the LCS with other variables. Overall, 76.6% of participants had at least one LCS. Results from the multivariate logistic regression analysis showed that females (crude odds ratio [OR] [95% confidence interval (CI)]: 2.725 [1.42, 5.22]), educated persons (3.747 [1.58, 8.84]), people with a higher number of COVID-19 reinfection (2.280 [1.30, 3.97]), having an underlying disease (1.996 [1.01, 3.93]), and COVID-19 severity (3.321 [1.037, 10.635]) had higher odds of LC than others (all p &lt; .05). Study findings provide additional clinical/sociodemographic data on risk for LC. These data may inform future research and clinical practice for potential risk identification and early intervention.<br/

    Fruit and Vegetable Consumption and the Risk of Bone Fracture: A Grading of Recommendations, Assessment, Development, and Evaluations (GRADE)‐Assessed Systematic Review and Dose–Response Meta‐Analysis

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    ABSTRACT Researchers have examined the link between consuming fruit and vegetables and the incidence of fractures for many years. Nevertheless, their findings have been unclear. Furthermore, the dose‐dependent relationship has not been examined, and the level of certainty in the evidence was not evaluated. We carried out a dose‐dependent meta‐analysis examining the relation between fruit and vegetables intake and fracture incidence. PubMed, Web of Sciences, and Scopus were searched until April 2023 for cohort studies evaluating the relation between fruit and vegetables and fracture incidence. Summary relative risks (RRs) were computed from complied data by applying random effects analysis. To examine the level of evidence, we utilized the approach called the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). Ten cohort studies comprising 511,716 individuals were entered. There was a nonsignificant relation between fruit and vegetables, as well as only fruit intake and any fracture risk. In contrast, high versus low analysis presented that vegetables consumption was linked to a 16% decrease in any type of fracture incidence (RR 0.84; 95% confidence interval [CI], 0.75 to 0.95; I2 = 83.1%; n = 6). Also, per one serving/day (200 g/day) increments in vegetables consumption, there was a 14% decline in the fracture risk (RR 0.86; 95% CI, 0.77 to 0.97; I2 = 84.7%; n = 5; GRADE = moderate). With moderate certainty, a greater consumption of only vegetables, but not total fruit and vegetables or only fruit, might reduce the risk of fracture. These associations were also evident in dose–response analysis. Large intervention trials are demanded to approve our findings. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research

    Increased Salivary Nitrite and Nitrate Excretion in Rats with Cirrhosis

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    Increased nitric oxide (NO) formation is mechanistically linked to pathophysiology of the extrahepatic complications of cirrhosis. NO is formed by either enzymatic or non-enzymatic pathways. Enzymatic production is catalyzed by NO synthase (NOS) while entero-salivary circulation of nitrate and nitrite is linked to non-enzymatic formation of NO under acidic pH in the stomach. There is no data on salivary excretion of nitrate and nitrite in cirrhosis.  This study was aimed to investigate salivary levels of nitrate and nitrite in a rat model of biliary cirrhosis. Cirrhosis was induced by bile duct ligation (BDL). Four weeks after the operation, submandibular ducts of anesthetized BDL and control rats were cannulated with polyethylene microtube for saliva collection. Assessment of pH, nitrite and nitrate levels was performed in our research. We also investigated NOS expression by real time RT-PCR to estimate eNOS, nNOS and iNOS mRNA levels in the submandibular glands. Salivary pH was significantly lower in BDL rats in comparison to control animals. We also observed a statistically significant increase in salivary levels of nitrite as well as nitrate in BDL rats while there was no elevation in the mRNA expression of nNOS, eNOS, and iNOS in submandibular glands of cirrhotic groups. This indicates that an increased salivary level of nitrite/nitrate is less likely to be linked to increased enzymatic production of NO in the salivary epithelium. It appears that nitrate/nitrite can be transported from the blood stream by submandibular glands and excreted into saliva as entero-salivary circulation, and this mechanism may have been exaggerated during cirrhosis

    Identification of clinically antibiotic resistant genes Aac(3)-IIa and Aac(6’)-Ib in wastewater samples by multiplex PCR

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    Background: Aminoglycoside antibiotics are widely used in medical centers, particularly to treat infections. The resistance developed against these agents is a huge concern in health care. A number of researchers have reported that hospital and municipal wastewaters are among the most important dissemination sources of these agent into the environment. Some, however, do not agree with this opinion. In the present study, the prevalence of aminoglycoside resistance genes was investigated in raw and effluent wastewater from hospital and municipal wastewater treatment plants. Methods: To conduct this descriptive-analytical study, 30 samples were taken according to sampling principles and cold cycle and transferred to the molecular laboratory. DNA was extracted by the freeze-thaw method using a kit (Promega). The genes aac(3)-IIa and aac(6’)-Ib which code aminoglycoside resistance were examined in this study. Results: The results indicated that the studied genes are present in 35% of urban and hospital wastewaters, and their frequency percentage is higher in hospital wastewater (52%) than urban wastewater (48%). The studied genes were identified in 61% of raw hospital wastewater samples; however, they were not detected in the output wastewater from the studied treatment plants. Conclusion: Although, the studied genes were not detected in the final effluent, there is a high potential for their release into the environment. The current study demonstrated that the coding genes of aminoglycoside antibiotic resistance are present in raw urban and hospital wastewaters. In the case of improper exploitation of wastewater treatment plants, the output water can contaminate other environmental sections, such as soil and water resources, and result in the emission of these contaminants
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