parviz malekzadeh

In this research, the effect of oil price shock on the return of the Iranian stock market has been evaluated using a new quantile-on-quantile approach. To do this, first, the oil price shock has been calculated using the structural vector autoregression method, and then the effect of the oil price shock on the return of the Iranian stock market has been investigated using the quantile-on-quantile approach. The statistical population consists of the data related to oil variables and the stock price index of the Iranian stock market. The statistical sample includes 200 observations of the monthly data related to the oil variables and the stock price index of the Iranian stock market during the period of 1385: 1 -1401: 12. The results of this research show that the effect of the oil price shock on the Iranian stock market varies across different quantiles of the Iranian stock market returns. A negative oil price shock has a larger effect on stock market returns when the stock market is bullish. Also, in the normal state of the stock market, a positive oil price shock has a large negative effect on stock market returns. Based on these observations, it is concluded that the relationship between oil price and stock market returns can depend on the nature of oil price shocks and the performance of the stock market.

In this work, considering a propulsion system of a planing boat, the effects of the air ducts with a square cross-section on the thrust, torque, performance, and ventilation of the surface piercing propeller (SPP) are investigated. The fluid flow is simulated using solving of the Reynolds-averaged Navier–Stokes equations (RANS) by the multi-physics computational fluid dynamics software STAR-CCM+. The simulations are validated by studying its grid independency and comparing the numerical results with the extracted results from the sea trial. Then, by considering the actual arrangement of the duct and SPP, the SPP is examined in the open water test in five cases for both condition of the lack and existence of the aeration. Also, the effects of aeration, the advance coefficient and the immersion ratio on the hydrodynamic characteristics of the SPP are studied. In a constant distance between the air duct and propeller, the results show that by increasing the hydraulic diameter of the air duct, the torque and thrust decrease, and the efficiency remains almost constant. Also, it is numerically demonstrated that the effects of the advance coefficient on the torque and thrust coefficients are different for the models with and without aeration.

Bell pepper (Capsicum annuum L.) belongs to the Solanaceae family, it contains high amounts of bioactive compounds such as phenolic, flavonoid, and antioxidant compounds. These nutrients have anti-cancer properties. However, bell pepper can usually be stored for several days during transport or at the time of sale in the store, or after purchase by consumers. In this period of time, the surface of the fruit loses its appearance and begins to lose its nutritional content. In order to postpone the senescence of bell pepper, various methods can be used, such as the atmosphere changing during the storage period, using chemical compounds, or natural compounds treatment. Researchers are looking for a compound that, while having the least harmful effect on human health, can give pepper the longest lifespan. Melatonin is an organic compound that has been studied in recent years on various biotic and abiotic stresses. The purpose of this study is to investigate the effect of melatonin treatment on the physiology of post-harvesting of bell pepper through its effect on the content of enzymatic and non-enzymatic antioxidant compounds during four weeks of storage time.

Materials and methods:

In this research, bell pepper fruit at the stage of physiological maturity was purchased from a local producer located in Tehran and immediately transferred to the research laboratory of Qom University. In the laboratory, the fruits that had damage or defects in appearance were discarded, and the rest were disinfected by immersing in a 1% (v/v) sodium hypochlorite solution for two minutes. In a preliminary experiment, bell peppers were treated with 25, 50, 100, 200, 250 and 300 µmol/L melatonin. Preliminary test results showed that 100 μmol/L melatonin had a significant effect on post-harvest appearance quality (primary test results not shown). Based on an initial experiment and selection of the best effective concentration in maintaining fruit quality, the treatment of 100 micromol/liter melatonin was used as a reference for the studies in this article. Bell peppers were divided into two groups, control and treatment, and after 2 hours immersion in 100 μmol/L as the treatment group and distilled water as the control group. Then it was kept for 4 weeks at a temperature of 4±1 degrees Celsius. In this research, the indicators of weight loss percentage, chilling injury percentage, antioxidant enzyme activity such as CAT and SOD, free radical content such as H2O2 and superoxide free radicals, and total phenol content, flavonoid content, and Phenylalanine amino lyase (PAL) and Tyrosine ammonia lyase (TAL) enzyme activity as enzymes controlling the phenylpropanoid pathway in weeks 0, 1, 2, 3 and 4 were evaluated after storage and with three repetitions.

The results of this study showed that the melatonin treatment of bell peppers was more effective in maintaining fresh weight during storage compared to the control group. In the first to the fourth week, the weight loss percentage of the melatonin treatment in the 2nd, 3rd and 4th weeks of storage was reduced by 39, 20 and 26.15%, respectively, compared to the control group. The results showed that there is a significant difference in the percentage of chilling injury in different weeks of storage between the control and the melatonin-treated group. The results showed that there is a significant difference in total phenol and flavonoid content between the control group and the melatonin-treated group during storage, and this increase was in line with the effect on the activity of PAL and Tal enzymes as key enzymes in the propanoid pathway. In both control and treated groups with melatonin, the content of hydrogen peroxide radical and superoxide radical showed a significant increase (p ≥ 0.05) during four weeks of storage at 4 ± 1 °C (Figure 3). However, in the second, third and fourth weeks of storage, the amount of hydrogen peroxide was significantly (p ≥ 0.05) lower in bell peppers treated with melatonin than in the control group. Compared to the control group, in bell peppers treated with melatonin during the second week of storage, the highest percentage decrease in hydrogen peroxide content was observed.The content of H2O2 and superoxide free radicals during the storage period showed a significant decrease compared to the control group, which showed that this result is consistent with the data obtained with the activity of antioxidant enzymes CAT and SOD.

The results of this research showed that the treatment of bell pepper with melatonin significantly reduced the effect on enzymatic and non-enzymatic antioxidant compounds compared to a control group, and these results confirm the results and the findings of previous studies about exogenous effect of melatonin. Harvested bell peppers during storage are susceptible to freezing stress, which increases the accumulation of reactive oxygen species such as superoxide radicals and hydrogen peroxide, and these compounds induce aging and reduce quality and marketability of agricultural products. The increase in the activity of PAL and TAL enzymes, especially in the first weeks of storage, may be due to the effect of exogenous melatonin on the expression and biosynthesis of genes involved in the phenylpropanoid pathway, and as a result, it leads to an increase in the activity of PAL and TAL enzymes. Increased production of enzymatic and non-enzymatic antioxidant system and activation of key enzymes of phenylpropanoid pathway (PAL and TAL) and increasing the content of total phenol and flavonoid compounds were observed. It seems that the enhanced antioxidant system has maintained the cell stability by reducing the concentration of reactive oxygen species and has increased the tolerance of the fruit to chilling stress. Phenolic and flavonoid compounds make plants resistant to abiotic and biotic stresses. In this study, the decrease in phenolic and flavonoid content due to storage at cold temperature in control group; was significantly increased in the pericarp of pepper treated with melatonin treatment. Based on the results obtained in this research, it can be said that melatonin treatment is beneficial on the post harvesting life of bell peppers and maintaining the appearance as well as the quality and levels of nutrients. Of course, for the final confirmation of this result, we need more studies on this or other fruits.

This study aimed to investigate the effect of the exogenous application of melatonin treatment on the activity of enzymes and compounds effective in the shelf life of tomato fruit during storage. Melatonin has been implicated in various aspects of cell growth and development and has recently been shown to play a role in protecting cells from biotic and abiotic stress. In this study, tomato fruit was immersed with 100 μM L-1 melatonin as a treatment and distilled water as a control group for 15 minutes, then kept at 4±° C for 4 weeks. The results showed that melatonin treatment by reducing the activity of superoxide dismutase and catalase enzymes was able to reduce the content of free radicals’ superoxide and hydrogen peroxide and thus the content of flavonoids, total phenol, vitamin C, and glucosinolate. These results showed that melatonin treatment can be effective by increasing the content of cell protective compounds and also by affecting the activity of antioxidant enzymes to increase the post-harvest life of tomato fruit.

Broccoli (Brassica oleracea) belong of the Brassicaceae family, contains high levels of bioactive compounds, such as vitamin C, phenolic compounds, and glucosinolates. These nutrients have antimicrobial, antioxidant and anti-cancer properties. However, broccoli can usually be stored for several days during transport or at the time of sale in the store or after purchase by consumers. During this period, their flowers start to turn yellow and their nutritional content decreases rapidly. In order to delay the aging stage in broccoli, various methods such as changing the atmosphere of the storage place, irradiating red light, the effect of plant hormones and treating chemical compounds can be used to maintain the appearance quality of broccoli and delay the aging stage. Various chemical compounds have been used to delay the aging stage in broccoli, but choosing a compound that has the least harmful effect on human health is one of the main priorities of scientists active in this field. One of these chemical compounds that has the least negative effects on health is melatonin. The purpose of this study is to investigate the effect of melatonin treatment on physiology after harvesting broccoli during storage.

In a primary experiment, broccoli was treated with 10, 25, 50, 100, 250, 400 and 600 μmol/L melatonin. Primary test results showed that 100 μmol/L melatonin had a significant effect on post-harvest appearance quality. Therefore, the 100 μmol/L melatonin treatment was used as a reference for more extensive studies in this paper. In this study a factorial experiment was conducted using a randomized completely design with three replication. Broccoli was divided into control and treatment groups, and after 20 minutes immersion in 100 µmol L-1 as treatment and distilled water as control. Then it was kept at a temperature of 4±1 °C for 4 weeks. In this research, the indicators of weight loss percentage, content of photosynthetic pigments, the activity level of antioxidant enzymes, the content of free radicals, and the amount of phenolic, flavonoid, vitamin C, and glucosinolate in weeks 0, 1, 2, 3 and 4 were evaluated after storage and with three repetitions.

The results of this research showed that broccoli treatment with melatonin was more effective in maintaining fresh weight during storage than the control. In the first to fourth weeks, the percentage of weight loss in the control group was 1.26, 1.57, 2.19 and 2.23 times higher than the melatonin-treated group, respectively. The results indicated that there was a significant difference (p<0.05) in the content of chlorophyll a and b in different weeks of storage between the control and the melatonin-treated groups. The melatonin treatment can increase the content of chlorophyll a, b and total chlorophyll by suppressing the activity of chlorophyllase enzyme. So that, melatonin treatment led to a decrease in chlorophyllase enzyme activity, and this decrease in the fourth week in the melatonin-treated group was about 47.8% less than the control group. The results indicated that there was a significant difference (p<0.05) in the content of vitamin C and glucosinolate between control and the melatonin-treated groups in during storage. Compared with control group, significantly higher total phenolic content was observed in the melatonin treated group in during of storage. Comparison of means showed that the content of flavonoids in broccoli treated with melatonin showed a general increasing trend, so that in the fourth week, the content of flavonoids in the treatment group was 3.67 times that of the control group. Measuring the activity of antioxidant enzymes showed that melatonin treatment was able to reduce the content of superoxide free radicals by increasing the activity of superoxide dismutase enzyme, so that in the group treated with melatonin, SOD activity increased by 35% and 47.6% in the third and fourth weeks, respectively.

In general, the effect of melatonin on broccoli is associated with increasing the activity of antioxidant enzymes and suppressing the activity of chlorophyll-degrading enzymes, which reduced the content of reactive oxygen species and increased the content of chlorophyll. Based on the data obtained in the present study, as a result of the increase in phenolic and flavonoid compounds, antioxidant enzymes and also antioxidant compounds such as vitamin C and glucosinolate, it improves the quality of broccoli. Generally, it seems that postharvest treatment with melatonin can be a useful method to maintain the appearance as well as the quality and nutrient levels of stored broccoli and increase its useful life.

In this study, the mechanism of cold stress tolerance in cucumber fruits pretreated with folic acid was investigated. Control group and the group treated with 5 mgL-1 folic acid were stored for 15 days at 4 °‌-C. The results showed that, in comparison with the control, treatment with folic acid resulted in reduced chilling injury and decreased electrolyte leakage. The cucumber fruits treated with folic acid showed higher chlorophyll contents in storage conditions with suppressed chlorophyllase enzyme activity. Exogenous folic acid treatment also increased the activity of arginine decarboxylase and ornithine decarboxylase resulting in the accumulation of polyamine contents. Also, higher levels of proline were observed in the fruits treated with folic acid, which is attributed to the increased activity of proline synthesizing enzymes △1-pyrroline-5-carboxylate syntheses and ornithine aminotransferase and also reduced activity of proline dehydrogenase enzyme that decompose proline. Generally, the results showed that folic acid treatment increased the resistance to the cold stress by regulating the activity of enzymes involved in the biosynthesis of proline, chlorophyll, and polyamines.

The increase in world population and the method of cultivation and food supply is one of the basic human problems/concerns in the twenty-first century. Traditional farming methods as well as modern horizontal greenhouses are not able to provide food for the next generation due to high energy costs and low yields. Therefore, today&#39;s farming method must change from the conventional horizontal to vertical method, a method that researchers and scientists have called vertical farming. Vertical farming is the construction of buildings within cities that, instead of cultivating on the land, cultivate in glass buildings with different floors and provide light from artificial sources and uses minimal water, and then recycle water along with breeding some plants and setting animal husbandry. This agricultural method minimizes the consumables for production as well as the post-production wastes; in contrast, the production efficiency is significantly higher due to the control of the culture medium. The rich industrialized countries of the world have invested in vertical farming projects, and this industry could be the savior of the human race in the coming decades.

The article is about the classification of the science into four types, proposing the evolution of science in four consecutive stages - creation of a discipline, its maturity, the expansion and consolidation and the prevalence of its applications. Consequently, we are faced with four types of scientists who are, mainly and particularly engaged in one of these stages. The first one involves introducing the components and phenomena of a new discipline of science along with its own language, justifying the new realm. In the second stage, scientists develop tools and methods providing a greater understanding of the new discipline. In the third stage, new knowledge reaches its maximum productivity, and the number of researches and publications also ranges its peak. The characteristics of the fourth stage, without making new discoveries, is the retaining and transfer of the knowledge and findings of all previous stages into a new realm. The view of knowledge developments is not limited to the perspective presented in this article. For instance, in his famous work, structure of scientific revolutions, Thomas S. Kuhn sees the structure of scientific revolutions in three stages: pre-paradigm, lead to the emergence of a new paradigm; The second stage, as he refers to normal science involves the advancement of knowledge in the context of the standing paradigm; The characteristics of the third stage, considered to be a scientific crisis within the context of the extant paradigm, to be challenged by a new one providing novel justifications and a broader perspective for the realities confronting existent state of science. However, according to the author, Kuhn’s view, which is to analyze the specific events of a paradigm, does not need to differentiate the stages of the evolution of the ideas from their “birth” to “death”, the purpose of the classification of science and scientists in current article. The benefit of the proposed approach goes beyond the addressing of the issue; emphasizing the very subtle and significant conclusion that scientists engaged in this or that stages of scientific progression does not necessarily mean their intellectual superiority, but indicates the special interests and talents of different scientists lead them to work in one of the evolutionary stages of a particular discipline. In addition, the perspective presented, helps the students to choose the field of their study based on own interests and talents; also, it helps scientists to be aware of their own interests and talents requirements, to pursue the field of research who belong to, and writing grant proposals in the context of the proper stage of the defined discipline.

Anxiety is known as a common problem in the general population. The aim of this study was to investigate the effect of Mindfulness-based cognitive therapy on working memory and problem solving.

A randomized controlled trial design was selected. The study population included all students between 20 and 30 years old in Tehran, from which 26 subjects were selected based on inclusion and exclusion criteria and randomly divided to experimental and control groups. Subjects in each group were tested before and after the intervention (8 sessions of MBCT) and in the follow-up phase (3 months) with the tools of the Tower of London (computer -based), Forward-backward Digit Span, Letter Number Sequencing test, as well as, the Beck's Anxiety Questionnaire.

results of MANCOVA showed that the experimental group was significantly different from the control group in the post-test and follow-up stages in working memory and anxiety. Significantly differences were found between the two groups for problem solving in the indicators of trial time, total time, number of errors and the number of correct trials, whereas no difference observed for planning time in problem solving.

According to the findings of this study, MBCT training through anxiety reduction can improve working memory capacity and problem solving components except the planning time.

‎The combination of generalization Type-I hybrid censoring and generalization Type-II hybrid censoring schemes create a new censoring called a unified hybrid censoring scheme‎. ‎Therefore‎, ‎in this study‎, ‎the E-Bayesian estimation of parameters of the inverse Weibull distribution is obtained under the unified hybrid censoring scheme‎, ‎and the efficiency of the proposed method was compared with the Bayesian estimator using Monte Carlo simulation and a real data set‎.

Analysis of road pavements responses such displacements, strains and stresses resulting from imposed impulsive loads, is one of the most important issues in pavement design. Various methods such as finite element, boundary element etc. can be used for analysis of this problem, but, as in all matters, the main goal is to reach high accuracy while spending less time for analysis, in this research, a new method of differential quadrature method (DQM) is used. In most studies implemented to date, the behavior of flexible pavement is considered as an elastic material but the asphalt concrte (AC) layer on top of the flexible pavement, behave as a viscoelastic material. The theory of viscoelasticity is an old subject, but its application in flexible pavement modeling, due to the time-dependent behavior of the viscoelastic materials and also the layered structure of flexible pavement, complicates the modeling.
In this paper, first, with incremental integration of Boltzmann's correspondence principle and using the generalized Wiechert model for viscoelastic behavior, incremental equilibrium equations of 3D axisymmetric condition are obtained and discritized in spatial domains using DQM. Then, in order to verificate, three-dimensional multilayered viscoelastic problems are modeled using Differential Quadrature Element method (DQEM), and the results of this method are compared with analytical solutions and finite element method (ABAQUS software) results. In the end, a flexible pavement structure with viscoelastic behavior under sinusoidal loading is simulated quasi-statically, and the effects of the viscoelastic response of the pavement under loading with different speed of vehicles as well as several performance indicators such as tensile stress and tensile strain under the AC layer, vertical stress on the subgrade, and vertical displacement of the pavement surface, which are commonly used in the design of the pavement, are investigated

objective of this study was to evaluate total phenolic content and antioxidant activity of leaf and different parts of fruit (hull, shell, and kernel) of Bene in Ilam province. Total phenolic content was determined with the Folin- Ciocalteu Reagent (FCR); antioxidant activity of methanolic extracts were examined by DPPH (2,2-diphenyl- 1- picrylhydrazyl), FRAP (ferric reducing antioxidant power) and nitric oxide radical scavenging methods. Among all the samples tested, leaf contained the highest total phenolic content followed by hull, kernel, and shell. There was a positive correlation between total phenol content and FRAP, Nitric oxide radical scavenging activity, and DPPH radical scavenging activity (r= 0.993, r= 0.972, and r= 0.969, respectively). The results indicated that antioxidant activity of leaf and hull extracts were significantly higher than kernel and shell extracts and this is attributed to their higher total phenolic and flavonoid contents. The FRAP, nitric oxide radical scavenging activity, and DPPH radical scavenging activity assay showed that leaf and hull extracts with potent activity can be introduced as a source of natural antioxidant. Compared with BHA, the extracts of leaf and hull revealed a remarkable DPPH free radical scavenging activity but shell and kernel extracts with higher EC50 had a weak activity.

The emergence of new pathogens and the increase in the number of multidrug-resistant strains in well-established pathogens during the past decade represent a growing public health concern globally. Therefore, it is important to introduce and replace new sources of drug such as medicinal plants with antimicrobial properties. The aim of the present sturdy was to evaluate the antibacterial effects of areal parts extract of Epilobium species collected from Iran. The results revealed that extract of all species studied, except (E. roseum subsp. subsessile) could inhibit the growth of bacteria. Based on our results, gram positive test bacteria showed the most susceptibility to the extracts compared to gram negative ones. None of the extracts could affect the growth of Pseudomonas aeruginosa and Enterococcus faecalis. We found that the willow herb extract inhibited the growth of bacteria in culture more effectively than related common antibiotics. Given that aerial parts of plant extract was utilized for this study, further investigation is recommended to determine which specific part of the plant (i.e., leaves, stem, and flowers) possess the antibacterial properties.

Aluminum toxicity is one of the most deleterious factors for plant growth in acidic soils because over 50% of the world’s potentially arable lands are acidic. In recent years, considerable research has been conducted to understand the mechanisms of Al toxicity and tolerance in plants. This paper reviews the effects of different concentration of Al on plant shoot, root physiological parameters such as length, fresh and dry weight, pigment content and antioxidant enzyme such as Catalase Ascorbate and Guaiacol peroxidase, malonyldialdehyde content. Maize (Zea mays L.) seeds were sterilized and these seeds were then germinated in Petri dish. The germinated seeds were allowed to grow at 27°C in darkness, and 5 ml of test solution was added to each Petri dish on the second day. The test solution contained 0, 25, 50, 75, 100mM AlCl3. Aluminum toxicity caused reduction in growth in all treatments. The plants exposed to Al exhibited a substantial decline in growth, pigment content, activities of guaiacol peroxidase (GPX), catalase (CAT) and ascorbate peroxidase (APX) and leaf structure. Data show that 50 mM Al caused increased in MDA content.

Non-Fourier heat transfer analysis of functionally graded (FG) spherical shells subjected to the radiative-convective boundary conditions at their inner and outer surfaces are presented. It is assumed that the material properties have continuous variations along the thickness direction. The incremental differential quadrature method (IDQM) as an accurate and computationally efficient numerical tool is adopted to discretize the governing differential equations in both the spatial and temporal domain. The fast rate of convergence behavior and accuracy of the method is investigated through different examples and also, the results are compared with those available in the open literature wherever possible. Comparison studies between the results of IDQM and Runge-Kutta method (RKM) are also performed to establish the superior computational efficiency of the IDQM with respect to RKM. After validating the present formulation and method of solution, the influences of different parameters on the temperature time history and temperature distribution of the FG spherical shells are investigated. It is shown that the radiation boundary conditions decrease the period of oscillation of temperature time history. Also, it is observed that by increasing the non-Fourier time constant, the non-dimensional temperature oscillatory behavior increases. On the other hand, the present study reveals that the IDQM, as an accurate and practically efficient method, can be used for the analysis of different problems in the fields of the oil and petrochemical engineering in the future.