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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    95-111
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    208
  • دانلود: 

    27
چکیده: 

Sluggish Cognitive Tempo is used to describe a particular type of attention deficit, concentration, and slowness in information processing. The aim of this study was to investigate the psychometric properties of the Sluggish Cognitive Tempo Scale (SCTS) of the parent form among Iranian children. The present study is a descriptive study. A sample of 1700 people was selected from the provinces of Tehran, East Azerbaijan, West Azerbaijan, Kurdistan, Fars and Khorasan using cluster sampling method. 122 subjects were excluded from statistical analysis due to incomplete answers to the questionnaires and thus the final sample was reduced to 1578 parents. The confirmatory factor analysis method and internal consistency were used to compute the Sluggish Cognitive Tempo Scale factorial validity and reliability, respectively. Also, in order to examine the construct validity of the Sluggish Cognitive Tempo Scale, we computed correlations between different dimensions of Sluggish Cognitive Tempo Scale with Attention Deficit Subscale of Mental Health Assessment Questionnaire for Children and Adolescents. The results of statistical results showed that this scale has structural validity, criterion and convergence in Iranian society. The results indicate that the scale is three factors and also the validity of the scale using Cronbach's alpha method and retest test after Approved two weeks. According to the findings of the present study, the parent form of the Sluggish Cognitive Tempo Scale (SCTS) has a good validity and reliability and it can be used in research related to slow cognitive multiplication in Iranian society.

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بازدید 208

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نویسندگان: 

SUR A. | KANORIA M.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    6
  • شماره: 

    1
  • صفحات: 

    54-69
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    404
  • دانلود: 

    0
چکیده: 

In this work, a new mathematical model of thermoelasticity theory has been considered in the context of a new consideration of heat conduction with fractional order theory. A functionally graded isotropic unbounded medium is considered subjected to a periodically varying heat source in the context of space-time non-local generalization of three-phase-lag thermoelastic model and Green-Naghdi models, in which the thermophysical properties are temperature dependent. The governing equations are expressed in Laplace-Fourier double transform domain and solved in that domain. Then the inversion of the Fourier transform is carried out by using residual calculus, where poles of the integrand are obtained numerically in complex domain by using Laguerre’s method and the inversion of Laplace transform is done numerically using a method based on Fourier series expansion technique. The numerical estimates of the thermal displacement, temperature and thermal stress are obtained for a hypothetical material. Finally, the obtained results are presented graphically to show the effect of non-local fractional parameter on thermal displacement, temperature and thermal stress. A comparison of the results for different theories (three-phase-lag model, GN model II, GN model III) is presented and the effect of non-homogeneity is also shown. The results, corresponding to the cases, when the material properties are temperature independent, agree with the results of the existing literature.

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    113-144
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    185
  • دانلود: 

    26
چکیده: 

One of the factors that can be the link between our intentions and actions and their external consequences is human agency, which indicates the conscious design and intentional execution of actions by the individual in order to influence future events.Objective and Method: This research with a developmental approach of psychometric method and method 1, examines the psychometric indices of the Human Factor Characteristics Scale using the classical theory of test score measurement and the graduated question-answer theory. The purpose of this study, which included high school students in Tehran, was selected by cluster sampling of 500 people as a sample size and statistical analysis was performed on 481 data. To collect the data, the ion Human Agent Characteristics Scale (2011) was used and the research questions were evaluated using IRTPRO and SPSS software.Results:The assumption of local independence based on Pearson x2 index was established by applying Simjima's calibrated question-answer theory and the assumption of being one-dimensional based on the analysis of multidimensional question-answer theory. Diagnosis parameters with question-answer approach and classical approach Test score Both item 25 approach had the lowest and item 2 had the highest diagnosis parameter. The answer thresholds for all the questions were so far apart that no option was covered by the other option, and the options were independently selected by individuals at intervals of theta. The total scale was calculated with Cronbach's alpha of 0.945, intentionality of 0.894, foresight of 0.780, self-reactivity of 0.871 and rethinking of 0.762. Also, the role of each item in internal consistency was investigated by the loop method, which all questions had a favorable role in internal consistency of this scale. The value of the validity coefficient obtained from the question-answer theory was obtained by marginal method for intentionality 0.92, forethought 0.85, self-reaction 0.91, rethinking 0.83..

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    1395
  • دوره: 

    34
  • شماره: 

    383
  • صفحات: 

    555-562
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    808
  • دانلود: 

    173
چکیده: 

مقدمه: نقص ایمنی متغیر شایع ( Common variable immunodeficiencyیا CVID)، فراوان ترین نارسایی ایمنی اولیه از نظر بروز علایم بالینی و مجموعه شرایط ناهمگنی است که با کمبود ارثی آنتی بادی (هایپوگاماگلوبولینمی) از حداقل دو ایزوتیپ ایمونوگلوبولین به همراه اختلال در بلوغ سلول های B و جهش سوماتیک، کاهش تعداد سلول های خاطره تعویض کلاس شده و نشده در گردش خون و اغلب با نبود پلاسماسل شناخته می شود. (BCMA) B-cell maturation antigen یکی از اعضای گیرنده خانواده نکروز تومور (TNFRSF یا Tumor necrosis factor receptor superfamily) است و بیشتر به خاطر عملکردی که در بقای پلاسماسل ها برای حفظ ایمنی هومورال با دوام دارد و همچنین، اهمیتی که در زنده ماندن پلاسماسل های با عمر طولانی مغز استخوان دارد، شناخته شده است. با توجه به این که یکی از مشخصات بیماری CVID، کاهش شدید یا فقدان پلاسماسل است، هدف از انجام این مطالعه، بررسی وجود جهش در ژن BCMA بیماران مبتلا به CVID در مقایسه با افراد سالم بود.روش ها: ابتدا 2 میلی لیتر خون کامل حاوی ضد انعقاد (EDTA) Ethylenediaminetetraacetic acid از 10 بیمار CVID و 10 داوطلب سالم گرفته شد. سپس،DNA  نمونه ها استخراج و پس از انجام(PCR) Polymerase chain reaction ، تعیین توالی شدند.یافته ها: پس از بررسی بیوانفورماتیک یافته ها و مقایسه با توالی مرجع، نتایج حاکی از عدم وجود جهش در اگزون های ژن BCMA بود.نتیجه گیری: علاوه بر بررسی وجود جهش در ژن BCMA، باید میزان بیان ژن و پروتئین BCMA و همچنین، عوامل کاهش دهنده بیان این ژن به منظور شناخت بیشتر نقش این ژن در این بیماری بررسی شود.

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اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    53
  • شماره: 

    3
  • صفحات: 

    182-191
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    166
  • دانلود: 

    46
چکیده: 

یکی از مسائل مهم در تولید بتن، تنوع محیطی است که بر بتن و عناصر ساخته شده از این ماده تأثیر می گذارد. با توجه به اهمیت ویژگی های مختلف بتن در شرایط کوتاه مدت و بلندمدت، این مقاله با هدف بررسی تأثیر شرایط دمایی اولیه بتن خود تراکم بر ویژگی های بلندمدت آن و تعیین دمای بهینه اولیه بتن می باشد. برای این منظور، آزمایش های متعددی در سه شرایط دمایی 5، 20 و 40 درجه سانتیگراد برای ارزیابی رئولوژی و خواص مکانیکی بتن تازه در محدوده 7 و 28 روز انجام شد. در این آزمایش ها، از مخلوط های معدنی جایگزین سیمان مانند میکرو سیلیس، خاکستر بادی و زئولیت برای ساخت نمونه های بتنی استفاده شد. نتایج نشان می دهد که خواص مکانیکی نمونه ها با افزایش دمای اولیه در کوتاه مدت افزایش می یابد، در حالی که چنین خواصی در طولانی مدت در مقایسه با نمونه های ساخته شده در دمای اولیه پایین تر کاهش می یابد. علاوه بر این، سیالیت بتن خود تراکم با افزایش دمای اولیه افزایش می یابد.

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بازدید 166

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    55-73
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    168
  • دانلود: 

    21
چکیده: 

AbstractThe aim of this study was to investigate the validity, reliability and factor structure of the "How I Think" questionnaire to assess cognitive distortions in Iranian students. The present research design is descriptive and psychometric studies. The statistical population of this study included all male high school students in city Dezful in the academic year 1399-1400, from which 316 students were selected by multi-stage random sampling and completed the How I think and Bass and Perry Aggression Questionnaires (for Convergent validity). Factor analysis, Cronbach's alpha and Pearson correlation were used to analyze the data using SPSS and AMOS 20 software. The results of factor analysis showed that the questionnaire consists of six factors and has good fit indices. The convergent validity of this questionnaire indicated a satisfactory correlation between the dimensions of the scale "How I think" with the Aggression Questionnaire (p <0.01). Cronbach's alpha and Split- half coefficients for the whole scale and its dimensions ranged from 0.66 to 0.92.The conclusion is that the Persian version of the "How do I think" questionnaire for measuring cognitive distortions in Iranian students has acceptable psychometric properties and can be used as a valid tool in research, educational and clinical situations.

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بازدید 168

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    1384
  • دوره: 

    10
  • شماره: 

    2
  • صفحات: 

    39-44
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    920
  • دانلود: 

    154
چکیده: 

میزان رشد و تولید مواد ضد میکروب حاصله از Oudemansiella spp. و نقش فاکتورهای مختلف موثر بر رشد و تولید این گونه ترکیبات با استفاده از روش آماری Variable simplex design  مورد بررسی قرار گرفت. نتایج حاصله نشان می دهد شرایط مطلوب برای رشد و تولید متابولیت های فعال عبارتند از: pH بین 5.6 تا 6.8، دمای بین 28 تا 30.6 درجه سانتی گراد، چرخش محیط کشت بین 137 تا 170 دور در دقیقه. در خصوص میزان گلوکز محیط کشت، نتایج نشان می دهد که قارچ مذکور در طیف وسیعی از غلظت های مختلف گلوکز قادر به رشد و تولید متابولیت می باشد. هم چنین نشان داده شد که کاهش غلظت قند گلوکز با استفاده از وجود قندهای کمپلکس موجود در عصاره مالت جبران می گردد و افزایش بیش از حد گلوکز (غلظت های بالاتر از 15 گرم در لیتر) سبب کاهش در تولید متابولیت های فعال می گردد.

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نویسندگان: 

METWALLY M.S. | MOHAMMED M.T.

نشریه: 

VIRTUAL

اطلاعات دوره: 
  • سال: 

    621
  • دوره: 

    1
  • شماره: 

    1
  • صفحات: 

    13-32
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    166
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 166

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اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    3
  • شماره: 

    1
  • صفحات: 

    37-45
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    312
  • دانلود: 

    0
چکیده: 

Natural convection heat transfer has many applications in different fields of industry; such as cooling industries, electronic transformer devices and ventilation equipment; due to simple process, economic advantage, low noise and renewed retrieval. Recently, heat transfer of nanofluids have been considered because of higher thermal conductivity coefficient compared with those of ordinary fluids. In this study; natural convection and entropy generation in a triangular enclosure filled by Al2O3 -water nanofluid affected by magnetic field considering Brownian motion is investigated numerically. Two inclined walls are maintained at constant cold temperature (Tc) while the bottom wall is kept at constant high temperature (Th) with (Th>Tc). In order to investigate natural convection, a computer program (FORTRAN language) based on finite volume method and SIMPLER algorithm has been used. Analyses is performed for volume fraction of nanoparticles 0, 0.02, 0.04, Hartmann number 0, 50,100, Rayleigh numbers 103,104,105 and angle of inclined walls 45o. In investigated angles and Rayleigh numbers; average Nusselt number is increased by enhancement of volume fraction of nanoparticles in a fixed Hartmann number. It is also observed that total entropy generation variations by increasing volume fraction of nanoparticles is similar to that of Nusselt number. By the results; effect of friction is always insignificant on generated entropy. It is observed that natural convection of nanofluid is decreased by enhancement of Hartmann number and its behavior is close to thermal conduction. It is also concluded that average Nusselt number and total generated entropy are decreased.

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نویسندگان: 

RAMIAR A. | RANJBAR A.A.

اطلاعات دوره: 
  • سال: 

    2011
  • دوره: 

    24
  • شماره: 

    2 (TRANSACTIONS A: BASICS)
  • صفحات: 

    131-142
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    351
  • دانلود: 

    0
چکیده: 

Laminar two dimensional forced convective heat transfer of Al2O3-water nanofluid in a horizontal microchannel has been studied numerically, considering axial conduction, viscous dissipation and variable properties effects. The existing criteria in the literature for considering viscous dissipation in energy equation are compared for different cases and the most proper one is applied for the rest of the paper. The results showed that nanoparticles enhance heat transfer characteristics of the channel and on contrast, viscous dissipation causes the Nusselt number and friction factor to decrease. The viscous dissipation effect may be emphasized by increasing Reynolds number and decreased by raising the exerted heat flux. Also, it was found that there is a critical Reynolds number below which the average Nusselt number of the nanofluid changes unusually with Reynolds number as a result of variable properties effect.

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