فهرست مطالب m. danesh

E-learning is a method for designing, , editing, presenting, and evaluating education that utilizes electronic capabilities and facilities to aid learning that educational institutions and learners have welcomed over the past three decades. However, because of the COVID-19 epidemic, e-learning has become the focus of wider public and political attention. Therefore, the study of learners' behavior in confrontation with e-learning and its various dimensions have been taken into consideration. In this research, the authors investigate the factors affecting the user's continued use of e-learning by utilizing the Information Systems Success Model and Flow Theory.

The present study is descriptive-correlative in terms of data collection method and applied research in terms of purpose. The variables of this research have been studied using a standard questionnaire. Furthermore, in this study, sampling was done using designed questionnaires distributed and filled out both online and physically among virtual students admitted to three universities in 2019 and before that (Tehran, Allameh Tabatabai, and Alzahra) located in Tehran. Finally, about 450 questionnaires were distributed in person and electronically among the virtual courses’ students of these three universities among which 23 questionnaires were either not returned or returned without answers, and about 30 cases were deleted due to being incomplete. On the whole, data from 390 questionnaires were analyzed in this study. The obtained data were analyzed using SPSS and Smart PLS software.

The results of this study indicate complete confirmation of the four hypotheses and their significance (T-Value more than 1.96) and complete rejection of the four hypotheses (T-Value less than 1.96). Approved hypotheses include confirming the positive and significant effect of information quality on user satisfaction, service quality on user satisfaction, enjoyment on user satisfaction, user satisfaction on user, information quality on user intention, system quality on user intention, and enjoyment on user continues continuous intention to use e-learning systems. According to this analysis, the most influential factor in the user's continued intention to use e-learning systems is the user's enjoyment of using the e-learning system. In addition, enjoyment has the most significant impact on user satisfaction. The hypotheses that have not been confirmed include the effect of system quality on user satisfaction, the effect of concentration on user satisfaction, the effect of service quality on the user’s continued intention to use e-learning systems, and the effect of concentration on the user continued to use e-learning systems.

In this study, the researchers have evaluated and studied the main components affecting the subject of the study in the context of e-learning in Iran, specifically among students of virtual courses at three universities in Tehran. Researchers have identified satisfaction as the key factor influencing the user's continued intention to use e-learning systems. So, the researchers have have identified and studied the factors affecting user satisfaction in using e-learning. The satisfaction variable is considered as a mediating variable, and its impact on the user's continued intention to use e-learning systems has been examined. Among the factors affecting user satisfaction, information quality, service quality, system quality, enjoyment, and concentration have been studied. According to the results, system quality and concentration did not affect user satisfaction. Also, service quality and concentration on the user's continued intention to use e-learning systems have not been significant.

The main object in optimizing reinforced concrete frames based on the performance is decreasing the initial cost or life cycle cost or total cost. The optimization performed here is with the requirement of satisfying story drifts and rotation of plastic hinges. However, this optimization may decrease seismic strength of the structure. Newton Meta-Heuristic Algorithm (NMA) was used to optimize three-, six-, and twelve-story reinforced concrete frames based on the performance and utilizing the cost objective function. The seismic parameters of the optimized frames were calculated. The results showed that the inter-story drifts at the performance level of LS controls the design. According to the results, the objective function for construction cost is not useful for the optimization of the reinforced concrete frames. Because the amounts of the over strength, the absorbed plastic energy, and the ductility factor for the optimized frames are low using the objective function for the construction cost.

 Reproductive performance of domestic animals has a great impact on the profitability of the farms. It has been shown that several factors such as breed, age, season and nutritional management affect the quality of the produced semen and consequently fertility of rams. Among various nutritional factors influencing semen quality, fat has a great impact on both quantity and quality of produced spermatozoa so that its value is correlated with cell membrane fluidity, potent intracellular signal transduction molecules, and susceptibility to oxidative damage. It has been postulated that by participating in sperm plasma membrane fatty acids (FA), the ingested fat can change the ratio of polyunsaturated to saturated fatty acids (PUFA: SFA) and thereby improve several aspects of sperm quality. Also, lipids comprise a wide-range class of molecules that not only is served as a source of energy but also play a crucial role in the structure and function of spermatozoa. Dietary n‑3 PUFA supplementation has also shown to improve semen quality parameters in rams. Flaxseed oil contains up to 90% PUFAs, of which about 50% is α-linolenic acid. Several studies conducted during past decades indicate that dietary flaxseed supplementation improves sperm parameters of different species such as bovine, goat and rabbit.

Materials and Methods :

Fifteen mature 3-5 years old Kurdish ram weighing 65±2.5 kg (mean ±SE) were randomly allocated into three groups during 12 weeks of the experimental period. Animals were individually fed a standard basal diet supplemented with different levels of flaxseed. Treatment included FLS-0 (basal diet; control), FLS-5 (basal diet containing 5% flaxseed) and FLS-10 (basal diet containing 10% flaxseed. Blood and fresh semen samples were collected at weeks 1 and 12 of the experiment. The collected samples were examined for sperm concentrations, sperm motility, viability, acrosome integrity, host test and fatty acids profiles. The testis circumference was measured with flexible cloth tape. The largest circumference of the testes and both scrotum was measured after pushing the testes firmly into the scrotum. To measure plasma concentrations of glutathione peroxidase and testosterone, blood samples were collected from the jugular vein of all the rams at the beginning and after 1 and 12 weeks of feeding experimental diet.

Results and Discussion:

 Flaxseed supplementation did not affect testicles circumference, however, supplementation of flaxseed increased plasma concentrations of testosterone in (10% flaxseed) FLS-10 group compared to (5% flaxseed) FLS-0 (P<0.05). Treatment, time and their interaction did not affect glutathione peroxidase (GPX) activity. Semen concentration, proportion of live sperm, total motility and plasma membrane functionality was higher in FLS-10 compared to FLS-5 and FLS-0 groups (P<0.05). Flaxseed supplementation tended to increase percentage of sperm with normal acrosome (P<0. 01); however, percentage of abnormal was decreased in FLS-10 compared to the other corresponding groups (P<0.05). Treatment, time and interaction effect of treatment × time did not affect LIN, STR, ALH and VCL (P>0.05). However, BCF and VSL were improved in FLS-10 group as compared to the FLS-5 and FLS-0 group (P<0.05). A significant interactive effect of treatment × time was noted for VAP, where flaxseed supplementation did not affect VAP at first week of the experiment but higher VAP was recorded in FLS-10 compared to FLS-0 and FLS-0 groups after 12 weeks of flaxseed feeding (P<0.05). Flaxseed supplementation did not affect percentage of myristic, palmitic, stearic, oleic, linoleic, EPA and DPA, but the proportion of DHA, and the ratio of n-3:n-6 PUFA and SFA:PUFA was affected by the treatments (P<0.05). Dietary inclusion of flaxseed increased proportion of DHA and n-3: n-6 PUFA ratio and decreased SFA: PUFA ratio in FLS-10 compared to FLS-5 and FLS-0 (P<0.05). The interactive effect of treatment × time on DHA, n-3: n-6 and SFA: PUFA ratio revealed that there was no significant effect between treatment after first week of the experiment; however, proportion of DHA and n-3: n-6 PUFA ratio was higher and SFA: PUFA ratio was lower in FLS-10 compared to FLS-5 and FLS-0 (P<0.05). the significant correlations between addition of 10% flaxseed and most of the evaluated semen characteristics including live sperm, total motility, plasma membrane functionality, and acrosome status following 12 weeks of treatment feeding was in agreement with previous findings in male goat and rabbit. Other fatty acids concentrations, such as, linoleic acid, and docosahexaenoic acid (DHA) was improved by dietary flaxseed supplementation.

Conclusion:

 It can be concluded that adding 10% flaxseed to the Kurdish ram diet out of the breeding season can improve sperm quality. Sperm fatty acid composition can also be affected by dietary fat. But more research is needed to look at the effects of other flaxseed products, such as oil and powder. It is recommended that similar studies be conducted during the breeding season and with other amounts of flaxseed.

Nowadays, energy crisis is one of the most important issues faced by most countries. Given the accommodation of a large population, high-rise buildings have a significant role in creating or resolving this crisis. A recent solution with regard to the optimization and reduction of energy consumption is using smart systems in buildings. In fact, with the help of modern knowledge, smart buildings consume energy in the right place and time. By transforming a simple building into a dynamic one, not only will it be able to adapt to changing environmental conditions, it will also consider the living habits of dwellers and comfort standards in order to provide maximum satisfaction. Moreover, the money spent on making smart appliances will be fully compensated after a short while, saving the overall costs and energy. This descriptive-analytical study, conducted using library resources, e-books and papers, is an attempt to examine the effect of smartization on optimizing and increasing the efficiency of high-rise buildings. The results of comprehensive surveys in various sectors related to smart buildings show that one can optimize energy consumption to take an effective step in solving global energy issues using smart systems in buildings. This study is devoted to energy consumption of smart systems employing an efficient continuous evolutionary meta-heuristic algorithm.

This paper presents a new method for regression model prediction in an uncertain environment. In practical engineering problems, in order to develop regression or ANN model for making predictions, the average of set of repeated observed values are introduced to the model as an input variable. Therefore, the estimated response of the process is also the average of a set of output values where the variation around the mean is not determinate. However, to provide unbiased and precise estimations, the predictions are required to be correct on average and the spread of date be specified. To address this issue, we proposed a method based on the fuzzy inference system, and genetic and linear programming algorithms. We consider the crisp inputs and the symmetrical triangular fuzzy output. The proposed algorithm is applied to fit the fuzzy regression model. In addition, we apply a simulation example and a practical example in the field of machining process to assess the performance of the proposed method in dealing with practical problems in which the output variables have the nature of uncertainty and impression. Finally, we compare the performance of the suggested method with other methods. Based on the examples, the proposed method is verified for prediction. The results show that the proposed method reduces the error values to a minimum level and is more accurate than the Linear Programming (LP) and fuzzy weights with linear programming (FWLP) methods.

The efficiency of braced structures depends significantly on structure response under seismic loads. The main design challenge for these type of structures is to select shape, number of spans, and type of connections appropriately. Therefore, introducing an optimized and cost-effective design including a certain level of safety and performance against natural hazards seems to be an inevitable necessity. The present work introduces a performance-based design for braced steel structures as well as an optimized arrangement of braces and connection types via using finite difference algorithm. The results show that the latter two factors are very important and necessary to achieve an optimized design for braced steel structures.

This study is devoted to discrete sizing optimization of truss structures employing an efficient discrete evolutionary meta-heuristic algorithm which uses the Newton gradient-based method as its updating scheme and it is named here as Newton Meta-heuristic Algorithm (NMA). In order to enable the NMA population-based meta-heuristic to effectively explore the discrete design space, a term containing the best solution found is added to the basic updating rule of the algorithm. The efficiency of the proposed NMA metaheuristic is illustrated by presenting five benchmark discrete truss optimization problems and comparing the results with literature. The numerical results demonstrate that the NMA is a robust and powerful meta-heuristic algorithm for dealing with the discrete sizing optimization problems of steel trusses.

While scholars have recently started to connect organizational factors in preparing a firm for corporate entrepreneurship to organizational outputs such as financial and innovative performance, there is less understanding of the mechanisms explaining these connections and their boundary conditions. In this vein, this study theorizes how and when Organizational Preparedness for Corporate Entrepreneurship (OPCE) enhances corporate financial and innovative performance. Our observation of 256 firms in the food industry of Iran indicates that OPCE promotes financial and innovative performance through the mediating role of entrepreneurial orientation. Moreover, the relationship between OPCE and organizational outputs is stronger when firms perceive their business environment more dynamic. This provides a better understanding of the way firms can enhance their performance, in particular in the novel context of Iran as a developing country.

suicide is one of the main reasons of mortality in the world and many countries involve with this major health issue. Pattern of suicide attempt is different in countries. Aim of this study was to assess the pattern of suicide attempt for suicide in patients who admitted in hospital.

this research was a descriptive analytical study. Participants include all patients who admitted along one year (2013-2014) in Imam Reza hospital in Bojnurd city with suicide attempt (based on psychiatric interview). Require data such as pattern of suicide and kind of drug used collected by researcher designed checklist. Data were analyzed by SPSS. Chi-square test was used to analyze the data.

281 patients with suicide attempt included in this study. 35.2% of samples were women and 64.8% was men. Mean age of samples was 24±9.07 year. We found a significant relation between variables such as age, gender and marital status and reason of suicide attempt. Drug poisoning was the most pattern of suicide attempt. Benzodiazepines were the most prevalence drugs used by patients for suicide. Argument with family or spouse was the most reason for suicide attempt based on patients self report.

The policy of the country is necessary to pay more attention to the issue of access of individuals to various drugs, as well as through the media and volunteers to manage and control the amount of medication in each house to inform and educate access to the people at high risk of unsafe drugs, less fatal to happen.