احسان یوسفی

The purpose of this study was to investigate the relationship between Principals' Instructional Leadership and school culture.

The research method was descriptive-correlational and based on structural equation modeling in terms of data collection. The statistical population of the study was all public school teachers in the first secondary school of Ardabil province in the academic year 2018-2019 with a volume of 3064 people (1684 males and 1380 females). The sample size was estimated at 346 people according to Krejcie and Morgan sample size determination table, which increased to 418 people (236 men and 182 women) considering the drop in subjects. The statistical sample of the study was selected using stratified random sampling method. Data were collected through questionnaire of Principal Instructional Management Rating Scale Hallinger (2013) with (AVE=0.66 & CR=0.90)  and questionnaire of School Culture of Grunert and Valentine (1998) with (AVE=0.62 & CR=0.90). The research data were analyzed by structural equation modeling method and AMOS24 & Smart PLS3 softwares.

The results showed that there is a significant positive relationship between the variables of educational leadership of principals and school culture. According to the results of this study, the educational leadership of the principal has a direct impact on school culture.

School leadership is essential for developing school culture. Accordingly, school principals can create a positive school culture by learning and applying specific leadership skills. In this regard, the Ministry of Education should first focus on enhancing leadership skills and then work on fostering a positive culture in schools nationwide.

Earthquake wave transmission from the source to the site is modeled by the ground motion prediction equations (GMPEs or attenuation equations). Considering the high contribution of these equations in the variability of the ground motion in the site, the selection of the appropriate relations for the region is of particular importance. The number of prediction equations is large, but there is no specific relationship for many areas, so it is necessary to use criteria to determine the best equations for probabilistic seismic hazard analysis(PSHA). In this paper, 62 relationships used by analysts in Iran and Tehran region are introduced to the three criteria of Rennie divergence, Euclidean distance and likelihood method, are ranked based on similarity with actual occurrence data, and the most suitable relationships for Tehran are introduced. The results show that the relationship of Zare and Sabze Ali (2006) in all three methods has a very good match with the Tehran region earthquakes. Also, some global relations have a better match than the regional relations obtained in Tehran. The results of the sensitivity analysis show a decrease in the effectiveness of the regional PSHA using the ranking. It also shows that relying on the opinion of experts brings more than 90% confidence in the selection of GMPEs, which seems sufficient in some cases. .If this level of accuracy is not sufficient, it is necessary to use the appropriate weighted equations in the analysis based on the physics-based ranking results. Otherwise, the results of the probabilistic seismic hazard analysis will fluctuate and may not have the sufficient reliability.

The purpose of this study was to investigate the relationship between Principals' Instructional Leadership and school culture. The research method was descriptive-correlational and based on structural equation modeling in terms of data collection. The statistical population of the study was all public school teachers in the first secondary school of Ardabil province in the academic year 2018-2019 with a volume of 3064 people (1684 males and 1380 females). The sample size was estimated at 346 people according to Krejcie and Morgan sample size determination table, which increased to 418 people (236 men and 182 women) considering the drop in subjects. The statistical sample of the study was selected using stratified random sampling method. Data were collected through questionnaire of Principal Instructional Management Rating Scale Hallinger (2013) with (AVE=0.66 & CR=0.90) and questionnaire of School Culture of Grunert and Valentine (1998) with (AVE=0.62 & CR=0.90). The research data were analyzed by structural equation modeling method and AMOS24 & Smart PLS3 softwares. The results showed that there is a significant positive relationship between the variables of educational leadership of principals and school culture. According to the results of this study, the educational leadership of the principal has a direct impact on school culture; Therefore, educational leaders must develop a school culture to improve school effectiveness.

 Escherichia coli is the normal flora of the human and animal intestine that sometimes causes pathogenesis within the intestine and urinary tract. The current study investigates resistance genes in Escherichia coli isolated from the toilets at the Islamic Azad University of Mashhad, Iran, and to perform genome sequencing in tetracycline-resistant strains.

 This cross-sectional evaluation was carried out on 200 samples collected over three months. Samples were cultured and isolated using eosin methylene blue agar medium (EMB). E. coli Samples were identified and used to evaluate the resistance genes by polymerase chain reaction (PCR). The E. coli isolates were used for an Antibiogram test to identify resistant strains. For the statistical analysis of antibiotics pattern, SPSS-22 and the Kolmogorov-Smirnov test were used.

Out of 200 samples, 41 isolates were identified as E. coli with the highest resistance rate to cefotaxime (74.60%) and the highest sensitivity rate to gentamicin (58.74%). Among the 20 isolates, 30%, 20%, 25% carried blaTEM-1, blaOXA-10 and blaOXA-48 genes, respectively. Among 38 tetracycline-resistant isolates, three isolates (7.89%) had tetA gene, and two (5.26%) had the tetR gene.

 In this experiment, most of the isolates were identified as E. coli and were resistant to antibiotics. To control the spread of E. coli infectious disease and arbitrary use of antibiotics, it is recommended to conduct some educational programs and social activities with the aim of increasing health awareness.

Microorganisms are more important than other sources in dye production because microorganisms have advantages such as rapid growth, higher yields, and easier extraction. Natural pigments are healthier than chemical types and their use is useful in various industries. The aim of this study was to isolate and extract the pyocyanin pigment from Pseudomonas aeruginosa isolates in order to preparation of colored paper and candle.

In this study, sampling was performed from different hospital environments in order to isolate P. aeruginosa. Environmental isolates of P. aeruginosa were identified using morphological features and differential biochemical methods. Confirmatory identification was performed by tracing the pbo1 gene using colony PCR. After extracting pyocyanin pigment with chloroform, finally, the produced pyocyanin was used to prepare colored paper and candle and the optical stability of pyocyanin was investigated.

From 43 environmental samples collected, 15 isolates of P. aeruginosa were identified and confirmed by molecular method. The mean of optical absorption (OD520) of pyocyanin after extraction was 0.488. Staining of paper and candle with the extracted pyocyanin was successful and the optical stability of pyocyanin was favorable.

Due to the rapid growth of bacteria and the possibility of its mass production in a short time and based on the results of this study, bacterial pigments can be used in various industries, including paper industry, and replaced by chemical dyes.

The purpose of this study was to analyze teachers' narratives of learning difficulties of elementary school students. This research was conducted with a qualitative approach and using the method of narrative research. First, 6 male and female teachers of an elementary school in Bilesvar city, who were chosen based on purposive sampling, sat a semi-structured interview until data saturation was obtained. The interviews were analyzed using thematic (categorical) analysis. In the deep analysis and perception of teachers' narrative, three main themes including individual factors with subtopics of ‘lack of motivation for progress’ and ‘learning disabilities’, family factors with the sub-themes of ‘low socio-economic status of parents’ and ‘poor emotional relationships between parents and children’ and school factors with the sub-themes of ‘inappropriate assessment methods’ and ‘unfavorable atmosphere in the classroom’ were identified. Due to the fact that in this study, the effective factors on the students’ learning problems were identified from the teachers' narratives, the necessary training should be provided to the teachers and families depending on the nature of the problem. Early detection of learning disabilities in children will be an effective step in preventing academic failure.

In this article, the failure of gearbox transfer of steel mill ingot in the company of Iran National Steel Group is studied. This shaft receives power from the electromotor and it’s inside another hollow axis. The shaft, power to rotate the ingot transfer roller by a spiral gear transmits to another axis. The roller make this system an important part of the ingot production line. This shaft many times will failure and replace it is a huge loss to the factory. Due to lack of the fundamental information about the map and kind of shafts after failure, measurement quantum were performed to determine the type of alloy-axis and to make the piece which these pieces have a short working life span and after undergoing loading, they were fractured. To find the causes of failure, the shaft was modeled in the Solid works software and it was inserted into the Ansys Workbench software for stress analysis. After using boundary conditions and loading, the Points that were susceptible to failure were identified. Also the conditions and defects that could lead to failure were analyzed. Finally to estimate shaft fatigue life, fatigue models were used and to improve the life of the piece suggestions and solutionswere presented.

Knowledge-based businesses active in the medical and health innovative eco-system play an important role in inhibiting the Covid-19 virus outbreak crisis. The current study deals with extracting and analyzing the key aspects of medical innovative eco-system and the role of innovative intermediaries in supporting the development of these businesses.

In terms of purpose, this study is developmental – applied, in terms of data collection, it is descriptive and survey and in terms of the origin of collected data, it is a mixed study (both quantitative and qualitative).The research tool for quantitative data collection was interview and qualitative data collection tool was a questionnaire created by the researchers themselves. In qualitative part, data-based method with the Glaserian approach (emergent and spontaneous) was used and in qualitative part structural equations and SMART-PLS3 software were used. The population of this study was faculty members of university of medical science (as experts) and CEOs and personnel of knowledge-based and technology-based companies that are active in medical innovative eco-system of Western Azerbaijan province, from which a sample of 162 subjects was chosen on the basis of Cochran formula.

Significance level and path coefficients of the structural model obtained from the analysis, approves the impact of ecosystem variables and developing knowledge-based businesses in controlling the Covid-19 virus outbreak crisis.

Meanwhile, the research results emphasize the role of universities and innovative intermediaries of medical innovative eco-system, which shows that “cultural and social” and “scientific and technological” aspects have the maximum effect in the development of knowledge-based businesses and innovative actions in Covid-19 virus control.

Escherichia coli O157:H7 is one of the main causes of transmitted diseases by food, including meat and meat products. The purpose of this study was to investigate the prevalence of E. coli O157:H7 contamination in Mashhad with the detection of rfbE gene.

For this study, 148 slaughtered beef samples from Mashhad (spring to winter, 2018) were randomly collected and transferred to the laboratory. The identification of E. coli O157:H7 was performed by biochemical methods and rfbE gene was detected by PCR colony method.

Based on biochemical tests, E. coli O157:H7 was isolated in 7 (4.73%) samples of slaughtered beef and after PCR colony; only 2 (1.35%) of these 7 samples were approved.
According to the results of this study, it can be concluded that beef can be considered as a major reservoir for E. coli O157:H7 and there is a potential for transmission of this pathogen to humans through the consumption of beef and its products. Also, the specific primers of rfbE gene were able to differentiate the E. coli O157:H7 colonies from other cultured colonies on the culture medium during the PCR process. The present research was performed for the first time in the city of Mashhad.

One of the most valuable water reservoirs in the north of Iran is Manjil Dam Lake which can have many other uses apart from agricultural water supply and power generation. For this reason, in order to qualitatively evaluate the water during one year and monthly, physical-chemical and comprehensive factors of phytoplankton have been studied as trophy indices in 5 stations in the lake. Results showed that average annual water temperature, light penetration depth, nitrite, nitrate, total phosphate, and dissolved oxygen were 15.33±6.21°C, 1.8±.35 m, 0.017±0.001 mg/l, 1.816±0.629 mg/l ,0.013±0.113 mg/l and 8.38±0.383 mg/l, respectively. Moreover, 22 different phytoplankton genera were identified that Chlorophyta, Cyanophyta, Pyrrophyta, Bacillariophyta, and Chrysophyta had frequencies of 42%, 44.3%, 6.3%, 2.1%, and 0.05%, respectively. Also, ecological indicators in terms of diversity and richness of phytoplanktons species in Manjil Dam Lake demonstrated that species composition changed with time and physical and chemical factors were determined to be the most important causes of these changes. However, certain genera were mainly predominant during the year and the change in Shannon-Wiener index showed a small amount. From the perspective of the trophy status based on the models used, it was determined that this reservoir dam was completely oligotrophic which was due to high levels of sediments entered from water resources of this dam, reducing the light penetration depth by a large degree.

After the victory of Islamic revolution, Iran's relations with the European Union experienced many ups and downs and by the organizational changes of this union, the emergence of new variables and developments in the middle east region and their effect, less come that these relationships has a steady and growing trend in a long term period. The negotiation process and nuclear diplomacy between Iran and Europe shows that on both sides have separate goals and motives. Iran has entered into negotiations and bargaining with Europe to neutralize American hostile policies and utilizing nuclear technology especially the fuel cycle. On the other hand, the purpose of the European Union is Iran's satisfaction to ignore from nuclear fuel cycle technology with giving incentive rates. In the other words, Europe is like the United States demanding unconditionally stop uranium enrichment and nuclear fuel production in Iran; Iran's nuclear case as focal point is in dispute Iran and the European Union as far as leaves tangible effects on their political relationships. In this article we will seek to answer this question that Iran's political relations with the European Union in years (88-92) passed which developments? The method of this research has been descriptive-analytic and information gathering by using library method.

The Iranian Light Source Facility (ILSF) booster main specifications including 250 ms ramp up, 2Hz repetition rate, and quasi-sinusoidal wave shape, up to this point have been the basis for calculations. Each family of magnets including Dipole, Quadrupole and Sextupoles will feed by individual power supply. In order to maintain constant transverse tunes and chromaticity while the beam is accelerated, quadrupole and sextupole magnet currents must closely track the current in the dipole magnets. In booster rings, feeding the high inductance load, tracking of Quadrupole and sextupole magnets, reducing output current fluctuation and having a precise high bandwidth current regulation system are particular challenges. In order to meet the requirements, it is necessary to have a fully digital controller to achieve a fast regulation system. The prototype power supply and its test results are described in this paper.

Knowledge is considered as the base and the most essential factor of competition and alongside the knowledge. Innovation is known as the vital factor for the survival of companies dealing with technology and knowledge based companies. The process of the creation of knowledge is the changing producing knowledge and at last changing it into products and services via concept of the role of innovation. The purpose of this research is to examine the effect of knowledge management on the innovation of the companies dealing with technology, which are located in the park of knowledge and technology of Urmia University. From the purpose point of view, this research is practical and from the nature point of view, it is descriptive and interconnected. The results of this research showed that there is a meaningful relation between knowledge management and innovation (of product, of process, gradual and basic). Therefore, paying more attention to knowledge management results in an increase in the innovations of the companies.