268 research outputs found

    Psychometric properties of the Persian version of co-rumination questionnaire

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    Background: Although growing studies support features of co-rumination as a vulnerability factor in internalizing symptoms and positive factor in friendship, little attention has been paid to the psychometric properties of the Co-Rumination Questionnaire (CRQ). Objectives: This study aimed to determine the psychometric properties of the Persian version of this questionnaire. Methods: This research is a descriptive-exploratory study and 550 high school students who were selected by random cluster sampling from schools in Tehran. They completed CRQ, Beck depression inventory-II (BDI-II), and ruminative response scale (RRS) from winter 2014 to summer 2015. Construct validity, internal consistency reliability, and factor structure were investigated. Results: The factor analysis identified two interpretable factors with the eigenvalue higher than 2. The results from concurrent validity measurement in the current study showed that co-rumination has a positive correlation with depression signs (P < 0.01) and rumination response style (P < 0.01). The CRQ validity was determined using the half-split method employing Spearman-Brown (0.82) and Guttman correlation test (0.81) and internal consistency (0.90). According to these values, this questionnaire has acceptable internal consistency reliability. Conclusions: The Persian version of CRQ has reliability and validity for assessing co-rumination among adolescent participants. This study provides primary evidence on the applicability of the Persian version of the CRQ in the Iranian population. Copyright © 2020, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited

    Influence of Al2O3 reinforcement on precipitation kinetic of Cu-Cr nanocomposite

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    In this paper, the kinetic of precipitation process in mechanically alloyed Cu-1 wt.% Cr and Cu-1 wt.% Cr/3 wt.% Al2O3 solid solution was compared using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The ageing kinetics in Cu¿Cr and Cu¿Cr/Al2O3 can be described using Johnson¿Mehl¿Avrami (JMA) and Sestak¿Berggren (SB) models, respectively. These different behaviors have been discussed in details. It was found that in presence of Al2O3 reinforcement, the ageing activation energy is decreased and the overall ageing process is accelerated. This behavior is probably due to higher dislocation density previously obtained during ball milling and Al2O3¿Cu interface. TEM observations confirm that Al2O3¿Cu interface and structural defects act as a primary and secondary nucleation sites, respectively.Gobierno de España ENE 2007-67926-C02-0

    Psychometric properties of the Persian version of co-rumination questionnaire

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    Background: Although growing studies support features of co-rumination as a vulnerability factor in internalizing symptoms and positive factor in friendship, little attention has been paid to the psychometric properties of the Co-Rumination Questionnaire (CRQ). Objectives: This study aimed to determine the psychometric properties of the Persian version of this questionnaire. Methods: This research is a descriptive-exploratory study and 550 high school students who were selected by random cluster sampling from schools in Tehran. They completed CRQ, Beck depression inventory-II (BDI-II), and ruminative response scale (RRS) from winter 2014 to summer 2015. Construct validity, internal consistency reliability, and factor structure were investigated. Results: The factor analysis identified two interpretable factors with the eigenvalue higher than 2. The results from concurrent validity measurement in the current study showed that co-rumination has a positive correlation with depression signs (P < 0.01) and rumination response style (P < 0.01). The CRQ validity was determined using the half-split method employing Spearman-Brown (0.82) and Guttman correlation test (0.81) and internal consistency (0.90). According to these values, this questionnaire has acceptable internal consistency reliability. Conclusions: The Persian version of CRQ has reliability and validity for assessing co-rumination among adolescent participants. This study provides primary evidence on the applicability of the Persian version of the CRQ in the Iranian population. Copyright © 2020, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited

    Spring Hydrograph Simulation of Karstic Aquifers: Impacts of Variable Re-charge Area, Intermediate Storage and Memory Effects

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    © 2017 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 24 month embargo from date of publication (June 2017) in accordance with the publisher’s archiving policyA simple conceptual rainfall–runoff model is proposed for the estimation of groundwater balance components in complex karst aquifers. In the proposed model the effects of memory length of different karst flow systems of base-flow, intermediate-flow, and quick-flow and also time variation of recharge area (RA) during a hydrological year were investigated. The model consists of three sub-models: soil moisture balance (SMB), epikarst balance (EPB), and groundwater balance (GWB) to simulate the daily spring discharge. The SMB and EPB sub-models utilize the mass conservation equation to compute the variation of moisture storages in the soil cover and epikarst, respectively. The GWB sub-model computes the spring discharge hydrograph through three parallel linear reservoirs for base-flow, intermediate-flow, and quick-flow. Three antecedent recharge indices are defined and embedded in the model structure to deal with the memory effect of three karst flow systems to antecedent recharge flow. The Sasan Karst aquifer located in the semi-arid region of south-west Iran with a continuous long-term (21-years) daily meteorological and discharge data are considered to describe model calibration and validation procedures. The effects of temporal variations of RA of karst formations during the hydrological year namely invariant RA, two RA (winter and summer), four RA (seasonal), and twelve RA (monthly) are assessed to determine their impact on the model efficiency. Results indicated that the proposed model with monthly-variant RA is able to reproduce acceptable simulation results based on modified Kling-Gupta efficiency (KGE = −0.83). The results of density-based global sensitivity analysis for dry (June to September) and a wet (October to May) period reveal the dominant influence of RA (with sensitivity indices equal to 0.89 and 0.93, respectively) in spring discharge simulation. The sensitivity of simulated spring discharge to memory effect of different karst formations during the dry period is greater than the wet period. In addition, the results reveal the important role of intermediate-flow system in the hydrological modeling of karst systems during the wet period. Precise estimation of groundwater budgets for a better decision making regarding water supplies from complex karst systems with long memory effect can considerably be improved by use of the proposed model

    Development of the conditional moment closure method for modelling turbulent combustion

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    Abstract Objective: The purpose of this study was to evaluate the effects of low-level laser irradiation (LLLI) on the in vitro growth characteristics and in vivo pathogenicity of Candida albicans in a murine model in the absence of a photosensitizer. Background data: C. albicans is an opportunistic commensal organism that causes a wide variety of diseases in human beings, ranging from superficial infections to life-threatening invasive candidiasis. The incidence of C. albicans infection is increasing, because of the greater frequency of acquired immunodeficiency conditions. A high recurrence rate has been reported for vulvovaginal and oral candidiasis, despite the best available treatments. Therefore, the search for new treatment modalities seems quite rational. Methods: Candida culture plates were exposed to common clinical energies of LLLI: 3, 5, 10, and 20 J at 685 nm (BTL Laser 5000, Medicinos Projektai, Czech Republic, Prague, max power output 50 mW) and 3, 5, 10, 30, and 50 J at 830 nm (BTL Laser 5000, Medicinos Projektai, Czech Republic, Prague, max power output 400 mW). Results: Following LLLI with energies >10 J at both 685 and 830 nm wavelengths, statistically significant effects were observed in vitro on the turbidimetric growth kinetics of C. albicans and in vivo on the survival rate of infected mice (p value </=0.05). Therefore, this energy could be considered a threshold for clinical investigation. Conclusions: Translating our data into the clinical setting, it can be proposed that a direct laser-based approach without using a photosensitizing dye can significantly reduce the pathogenicity of Candida albicans. It can also be concluded that laser light at specific wavelengths could be a possible promising novel treatment for superficial and mucocutaneous C. albicans infections

    A surrogate model for simulation–optimization of aquifer systems subjected to seawater intrusion

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    This study presents the application of Evolutionary Polynomial Regression (EPR) as a pattern recognition system to predicate the behavior of nonlinear and computationally complex aquifer systems subjected to seawater intrusion (SWI). The developed EPR models are integrated with a multi objective genetic algorithm to examine the efficiency of different arrangements of hydraulic barriers in controlling SWI. The objective of the optimization is to minimize the economic and environmental costs. The developed EPR model is trained and tested for different control scenarios, on sets of data including different pumping patterns as inputs and the corresponding set of numerically calculated outputs. The results are compared with those obtained by direct linking of the numerical simulation model with the optimization tool. The results of the two above-mentioned simulation–optimization (S/O) strategies are in excellent agreement. Three management scenarios are considered involving simultaneous use of abstraction and recharge to control SWI. Minimization of cost of the management process and the salinity levels in the aquifer are the two objective functions used for evaluating the efficiency of each management scenario. By considering the effects of the unsaturated zone, a subsurface pond is used to collect the water and artificially recharge the aquifer. The distinguished feature of EPR emerges in its application as the metamodel in the S/O process where it significantly reduces the overall computational complexity and time. The results also suggest that the application of other sources of water such as treated waste water (TWW) and/or storm water, coupled with continuous abstraction of brackish water and its desalination and use is the most cost effective method to control SWI. A sensitivity analysis is conducted to investigate the effects of different external sources of recharge water and different recovery ratios of desalination plant on the optimal results

    National and sub-national burden of chronic diseases attributable to lifestyle risk factors in Iran 1990-2013; study protocol

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    Background: Non-communicable diseases, as the major public health problem, are caused by different risk factors. The main leading lifestyle risk factors for most diseases burden in Iran are unhealthy diet, physical inactivity, and smoking. The aim of this study is to provide data collection and methodology processes for estimating the trends of exposures to the selected lifestyle risk factors and their attributed burden at national and sub-national levels. Methods: Systematic review will be performed through PubMed/MEDLINE, Scopus and ISI/Web of Science as well as Iranian databases such as IranMedex, Irandoc and Scientific Information Database (SID). In addition, hand searching of unpublished data sources will be used to identify relevant population-based studies. The searched studies will be included only if it is reasonably population-based and representative, and exposure data has been reported or could be plausibly obtained from the study. For risk factors with no surveys identified, other sources of potential data will be considered. The target population is healthy Iranian adult population living within Iran from 1990 to 2013. Other data sources include national censuses, national registration systems, and national and sub-national surveys. Spatio-temporal Bayesian hierarchical model and Bayesian multilevel autoregressive model will be used to overcome the problem of data gaps in provinces, and in some age or sex groups or in urban/rural areas. The problem of misaligned areal units will be also addressed in these models. Conclusion: National and sub-national assessment of major lifestyle risk factors such as unhealthy diet, physical inactivity, and smoking is necessary for priority setting and policy making in different regions of Iran

    Dual-pump Kerr micro-cavity optical frequency comb with varying FSR spacing

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    In this paper, we demonstrate a novel dual-pump approach to generate robust optical frequency comb with varying free spectral range (FSR) spacing in a CMOS-compatible high-Q micro-ring resonator (MRR). The frequency spacing of the comb can be tuned by an integer number FSR of the MRR freely in our dual-pump scheme. The dual pumps are self-oscillated in the laser cavity loop and their wavelengths can be tuned flexibly by programming the tunable filter embedded in the cavity. By tuning the pump wavelength, broadband OFC with the bandwidth of >180nm and the frequency-spacing varying from 6 to 46-fold FSRs is realized at a low pump power. This approach could find potential and practical applications in many areas, such as optical metrology, optical communication, and signal processing systems, for its excellent flexibility and robustness
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