Showing 7 results for javdan
Volume 11, Issue 2 (Spring 2025)
Abstract
Background: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a significant global health threat. The host immune response determines the disease severity, with factors like human leukocyte antigen (HLA) genes, age, sex, and nutritional status influencing outcomes. HLA genes, known for their genetic diversity, are implicated in determining susceptibility and severity of infectious diseases. This study investigated the association between HLA class I genotypes and COVID-19 severity in the Isfahan population, Iran.
Materials & Methods: Blood samples were collected from 34 COVID-19 patients with varying levels of disease severity (severe, moderate, and mild). HLA genotyping was performed using polymerase chain reaction-sequence specific primers (PCR-SSP), and in silico analysis assessed the affinity of viral peptides to HLA alleles.
Findings: Statistical analyses revealed that HLA-C07 was more prevalent in patients with severe COVID-19, suggesting a potential association between this allele and the disease severity. Furthermore, HLA-A01 was more prevalent among severe cases, while HLA-A02 and HLA-A03 were less frequent, indicating a possible predisposing role for HLA-A01 and protective roles for HLA-A02 and HLA-A*03.
Conclusion: These findings highlight the role of HLA molecules in COVID-19 severity and offer insights into genetic factors influencing outcomes. Understanding the association of specific HLA alleles, such as HLA-C07, HLA-A01, HLA-A02, and HLA-A03, with the disease progression lays a foundation for advancing personalized preventive and therapeutic approaches. These results contribute to knowledge on host genetics in infectious diseases, paving the way for further research and therapeutic strategies.
Jaafar Haqiqat, Ebrahim javdan,
Volume 14, Issue 4 (winter 2014 2015)
Abstract
Since the breakdown of the Bretton Woods system of fixed exchange rates, both real and nominal exchange rates have fluctuated widely. Empirical findings indicate significant impact of exchange rate uncertainty on macroeconomic variables such as output, trade, and investment. This article investigates the impact of the real exchange rate uncertainty on total factor productivity (TFP) in agriculture sector of Iran during the period of 1974-2007. The uncertainty of real exchange rate is defined as the conditional variances obtained from Exponential Generalized Auto-Regressive Conditional Heteroscedasticity (EGARCH) model. The econometric estimation using Auto-Regressive Distributed Lag (ARDL) approach shows that the real exchange rate uncertainty has a significant and negative effect on TFP in Iran's agriculture sector in long- and short term. According to the results, in order to reduce the real exchange rate uncertainty, it is recommended that the appropriate policies should be made by policymakers to lessen the difference between nominal and real exchange rates.
Volume 15, Issue 4 (12-2015)
Abstract
Shear modulus is one of the most important properties of soil deposit that should be evaluated as a preliminary step for site response analysis. Although numerous studies have been conducted to evaluate this parameter for silicate soils, there are considerably less studies on calcareous soils. However, extensive regions of the earth is covered with calcareous soils. This type of soil is typically observed near offshore hydrocarbon industries, such as the Persian Gulf. Calcareous sand is the accumulation of pieces of carbonate materials, originated from reworked shell fragments and skeletal debris of marine organism. These soils typically include huge oil and gas reservoirs which are continuously under an extending construction. Therefore, assessment of dynamic behavior of calcareous soils is a vital step for engineering projects. In this study, shear modulus of calcareous sand are investigated in the range of small and large strains using resonant column and cyclic triaxial tests, respectively. Bulk samples of Boushehr sand were collected from the North bank of the Persian Gulf near the Boushehr port. Preliminary mineralogy tests were conducted in order to estimate carbonate content of the samples. The sand contains considerable level of carbonate content and skeletal structure of the soil can be observed easily. Remolded samples of this sand were prepared via dry deposition method for either triaxial or resonant column tests. The results are presented in terms of shear modulus versus shear strain. The effects of confining pressure and relative density on the shear modulus of the calcareous soil are investigated. Moreover, for evaluating the effect of stress anisotropy on the shear modulus of calcareous soil, dynamic and cyclic tests were conducted under both isotropic and anisotropic conditions. The experimental results confirm that confining pressure has an important influence on the shear modulus of the tested samples. Increase of the mean confining pressure and relative density increases the shear modulus of the sand, as previously reported for the other sands. The results indicate that the effect of stress anisotropy on dynamic properties of calcareous sand is less important than those of mean confining pressure and relative density. With increasing mean confining pressure, the effect of relative density and initial stress anisotropy on the shear modulus increases. The normalized shear modulus are compared with the G-reduction ranges proposed for silicate sand by the previous researchers. This comparison show the need for some modification of the previous proposed ranges for normalized shear modulus curves. Finally, a modified hyperbolic model is presented for estimating the normalized shear modulus of Boushehr calcareous sand. It is demonstrated that the proposed model has more capability for prediction of the experimental G-reduction curves, compared with the models recommended for silicate soils. One advantage of the proposed model is the simple correlation developed for the reference shear strain in terms of initial effective confining pressure. The modified hyperbolic model presented in this study can be employed for site response analysis of the calcareous deposits of the Boushehr city.
Esmaeil Pishbahar, Ebrahim javdan,
Volume 15, Issue 4 (winter 2016)
Abstract
Given the large weight of food in the households’ consumption basket and its limited substitutability with other goods, food price fluctuations are of sizeable impacts on overall consumer prices. The reaction of the food prices to monetary shocks has been the subject of much empirical researches in the recent years. This study examines the impact of monetary shocks on food prices in Iran. To do this, the study adopts Johansen-Juselius and Error-Correction models using time-series data over the period 1973-2008. Using Hodrick-Prescott filter, the monetary shocks were obtained. The results showed that in the long-run positive monetary shocks have significant effects on food prices in Iran. Therefore, policies and strategies should be such that minimize the negative effects of monetary shocks on the food prices.
Volume 16, Issue 9 (11-2016)
Abstract
Metallic alloys exhibit rheological behavior similar to non-Newtonian fluids in the semi-solid temperature range. This behavior can be described using rheological models. In this study, the viscosity of semi-solid 7075 aluminum alloy was measured by using the results of load-displacement signals obtained from two different experiments: parallel plate compression and backward extrusion. The obtained data were used to determine the parameters of the Cross model in a wide range of shear rates. The effects of temperature (solid fraction) and shear rate were studied on the viscosity of the alloy. The results showed that with increasing temperature and decreasing the solid fraction the resistance to flow decreases, resulting in a reduced amount of applied forces. This reduction in applied forces results in reducing the viscosity. It was observed that the behavior of semi-solid alloy is shear thinning in which the viscosity decreases with increasing shear rate. Also, the calculated viscosity values of the four parameters Cross model were in good agreement with the obtained experimental results in a wide range of shear rates. The simulation results showed a good agreement of the presented model for predicting the rheological properties and flow behavior of the semi-solid alloy in a wide range of shear rates.
Dr Mehdi Shabanzadeh Khoshrody, Dr Omid Gilanpour, Dr Ebrahim javdan, Dr Mohsen Rafaati,
Volume 22, Issue 3 (Autumn 2022 2022)
Abstract
The currency fluctuations intensified in Iran from the end of 2017. In order to manage the foreign exchange market, from the beginning of 2018, the government economic staff allocated preferential currency at the rate of 42000 Rials per US dollar to basic goods’ imports. The main purpose of this policy was to prevent the spread of currency inflammation to the market of basic goods needed by the people and to benefit the lower income deciles of society. However, today, three years after the implementation of this plan, many experts believe that the implementation of the preferred currency subsidy policy has resulted in high costs and due to failure to control rising prices, has not been able to ensure the stability of target food consumption among households. On the contrary, proponents of this policy believe that the effect of the preferred currency subsidies policy on controlling the growth of product prices in the final market and ultimately household consumption has been significant. Therefore, the question arises here is that whether the subsidy paid in the form of preferred currency policy reaches the final consumer and has a significant effect on his level of consumption? With this approach, the present study evaluates the effect of preferred currency subsidies policy on food consumption in urban areas of Iran. In order to achieve this goal, first, the theoretical model of the present study is explained by applying theoretical foundations in various studies. It is worth mentioning that the information required for the study is collected during the period 2005-2020 and analyzed in the form of PANEL ARDL model. The results show that although the preferred currency subsidies policy has a positive and significant effect on household consumption, but this effect is not remarkable. At the same time, according to the results, the price index of food groups and exchange rate fluctuations have negative effects on food consumption in the short and long term and in contrast, increasing the income of urban households has a positive and significant effect on food consumption in the short and long term. Finally, the results of the error correction model (ECM) show that due to the low speed of adjustment, the effects of currency shocks have high durability in the Iranian economy.
Volume 25, Issue 1 (Spring 2021)
Abstract
Introduction
Event tourism as one of the types of tourism that according to Getz, has been proposed in the tourism industry and research community for several decades, is one of the important motivating factors in tourism and in programs. The development and marketing of most areas is an important factor. With this description, in recent decades, the event management sector is evolving and becoming a strong industry that has been considered through the development of communities. In this regard, in order to achieve success, it is necessary to pay attention not only to the shareholders, but also to all groups and individuals who influence or are affected by the development of the event in any way.
The present study was organized in line with regional development by event management which has identified, prioritized and analyzed different dimensions of the success that affects the perception of organizers.
Methodology
In this study with combined methodology and descriptive-analytical survey method, different dimensions of the components that affect the perception of organizers are identified, prioritized and analyzed.
For this purpose, the various dimensions categorized by the panel of experts, and all the effective components on the perception of the organizers were presented. Afterwards, by a questionnaire among 50 organizers of the Ferdowsi commemoration in Toos area of Mashhad city, which were selected by Delphi counting technique, their perception of event was measured and then analyzed by fuzzy TOPSIS method.
Results and discussion
In this research, in a step beyond the previous researches, the dimensions affecting the event have been prioritized, and provide a more detailed roadmap for the organizers on how to pay attention to the dimensions affecting the success of an event.
The results show that physical perception with the first rank has the greatest impact on the process of understanding the event for the organizers. In other words, physical space, accessibility, infrastructure development, diverse and aesthetic content qualities, and imagery can create a better and more effective understanding in management of events.s.
