Showing 61 results for لا
Volume 8, Issue 1 (12-2009)
Abstract
This investigation was carried out to identify type and extent of mycorrhizal distribution in Tandooreh National Park and determine the effects of Ca and K concentration on mycorrhizal development in vitro on Zea maiz using natural soil as substrate. Soil and root samples were taken from top 30 cm soil using a 10cm diam. steel borer from 7 stations located at 11 50 to 2300m heights from sea level. At least 2 plots of 100m2 (10 ´10m) were sampled. Plant samples were also collected. Sections were prepared from root samples were longitudinally sectioned and stained with Lacto phenol cotton blue. Spores of mycorhizae were isolated usingcentrifugation60% in sucrose solution centrifugation at 9000 rpm for 2 min. Surface characteristics of spores were used in their identification. 53 species of plants were identified. Majority of plants (50] species had vesicular aruscular mycorrhizae (greater than 90%). Seven species of Glmous were present in the rhizosphrere of all stations. Seedlings of maiz were grown in the pots containing Tandooreh soil with or without addition of given amounts of Ca and K in a factorial statistical plan. After 8 weeks of cultivation in greenhouse conditions, the plants were removed and their roots were separated and stained using method of Hyman and Philips to detect type and extent of mycorrhization. Dry weight and nutritional elements were determined in roots and shoots. K and Ca added in certain concentrations to soil were effective on mycorrhizal development. Ca and K had synergistic ionic effects in lower concentrations and showed antagonistic ionic effects in high concentrations in mycorrhizal development. There was also a correlation between mycorrhizal development and absorbed amount of Ca and K in shoots.
Volume 8, Issue 3 (2-2009)
Abstract
The Javaherdasht basalts have considerable outcrops in the north part of Alborz mountains in the east of Guilan province.The petrographical, geochemical and isotopical evidence is indicative of the contamination of the basalts with continental crust. The petrographical evidence such as corosion gulf and crenated margins in pyroxene phenocrysts and chemical composition difference between clinopyroxene phenocrysts margins with matrix clinopyroxenes suggest of crustal contamination and nonequilibrium due to the change of matrix composition as compared with pre-existed phenocrysts in rock .The depletion in elements such as Zr, Nb,TiO2 ,P2O5 and enrichment of LIL elements,high ratios of Pb/Nd and Ba/Nd,low content of Zr/Nb,Y/Nb,Ce/Pb, positive correlation between SiO2 and 87 Sr/86Sr and positive correlatian between MgO and Nd are geochemical and isotopical evidences of crustal contamination of these basalts. Our studies show that these basalts have a clear elemental equilibrium with lower and middle crust rocks and that they have been contaminated with them.
Volume 8, Issue 3 (2-2009)
Abstract
Malayer granitoid rocks, as a part of Sanandaj-Sirjan plutonism, are located at latitude 34°00´-34°18´ and longitude 48°30´-48°52´. Tectono-magmatic investigation on the history of Sanandaj-Sirjan Zone attributed the formation of these plutonic rocks to convergence of Iranian and Arabian plates in conjunction with subduction of Neo-Tethys in the western part of Sanandaj-Sirjan Zone. Geochemical studies of Major and Trace elements on Malayer granitic rocks reveal that these granitic plutons are formed in a compressive environment, such as active continental margin in the convergent zone of oceanic crust and continental plate at the magmatic arc of continental margin. High ratio of LILEs/HFSEs and negative anomaly of Sr, Nb, Ba and Ta confirm the relation of these granitoids to subduction zone. These, also point out the role of shallow continental crust in formation and evolution of granitoidic magma. Broad range of mineral composition in petrographical observations and large variations in field studies, high-K calc-alkaline affinity and assessment of trends observed in AFM, K2O-SiO2, FeO-MgO diagrams versus those of plutons of known tectonic setting accentuate the similarities between Malayer granitic rocks and Andian type Magmatic Arc of Active Continental Margins and as a result highlights the role of upper mantle mafic magmas and tectonic movement in formation of their parental magma.
Volume 8, Issue 3 (2-2009)
Abstract
In this study, trace determination of benzene, toluene, ethyl benzene and xylenes isomers (BTEX) in aqueous samples was carried out by static headspace-gas chromatography-mass spectrometry. Important parameters of extraction by headspace such as extraction temperature, extraction time, sample volume and salt concentration were optimized. Under optimal conditions (extraction temperature: 70 oC, salt concentration: 4M, extraction time: 20 min and sample volume: 10 mL) and using selected ion monitoring (SIM) mode of mass spectrometer, detection limits of BTEX were found to be in the range of 1.0-2.2 µg/L .
Volume 8, Issue 3 (2-2009)
Abstract
The data gathered from implemented investigations provides enormous information yet if not organized properly, they would not yeild useful and credible results. GIS cannot only organize the mineral potential-related information, but also integrate different datasets and produce quickly and precisely-required mineral potential maps. It also supports the spatial decision-making process. Here, we have used GIS to produce the mineral potential map of Sonajil porphyrtic copper prospect to determine sufficient drilling localities. The utilized layers include rock type, alteration, mineralization indicators, anomaly zone of Chargeability and Apparent resistivity, anomaly of Copper, Molybdenum and gold. After information preparation, Factor maps were weighted and integrated in the inference network and mineral potential map was prepared. Using Fuzzy logic operators in inference network can eliminate defects in other models and provide more flexible integration of factor maps. With respect to prepared mineral potential map, most probable mineral potential zones of porphyrtic copper are located in two north-east and south-west parts of studied area. Eventually, the degree of correlation between mineral potential maps and those operated exploration boreholes has been estimated for two different classes, 90.91% and 83.33%. Regarding to the resulted mineral potential map, some new promising drilling localities have been suggested. Comparison of the high potential points indicated by our mineral potential maps with those previous drilled boreholes reveals about 85% miscorrelation. In other words, if the present proposed methodology had been performed before drilling operation, about 600,000$ could have been saved in this stage.
Volume 9, Issue 1 (10-2010)
Abstract
A direct method to determine numerical solutions of linear Volterra integro-differential equations is presented in this paper.. This method is based on block-pulse functions and its operational matrix. By using this approach, the integro-differential equation reduces to a linear lower triangular system of algebraic equations which can be solved easily. Some numerical examples are provided to illustrate accuracy and computational efficiency of the method. MSC: 45J05 41A30
Yadollah Ordokhani,
Volume 9, Issue 1 (10-2010)
Abstract
در این مقاله یک روش عددی مناسب برای حل معادلات انتگرال- دیفرانسیل فردهلم غیر خطی با تأخیر زمانی ارائه شده است. روش مبتنی بر بسط تیلور می باشد. این روش معادله انتگرال- دیفرانسیل و شرایط داده شده را به معادله ماتریسی که متناظر با یک دستگاه از معادلات جبری غیر خطی با ضرایب مجهول بسط تیلور می باشد تبدیل می کند، که از حل دستگاه، ضرایب بسط تیلور تابع جواب به دست می آید. سپس با مثال هایی کارایی روش را ارزیابی می کنیم.
Volume 9, Issue 1 (10-2010)
Abstract
This paper presents an appropriate numerical method to solve nonlinear Fredholm integro-differential equations with time delay. Its approach is based on the Taylor expansion. This method converts the integro-differential equation and the given conditions into the matrix equation which corresponds to a system of nonlinear algebraic equations with unknown Taylor expansion coefficients, so that the solution of this system yields the Taylor expansion coefficients of the solution function. Then, the performance of the method is evaluated with some examples
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Volume 9, Issue 2 (10-2010)
Abstract
Fe Doped CdS nanopaqrticles have been synthesized by a wet chemical method and TG used as a capping agent. The particle size of the nanoparticles calculated from XRD and optical methods has been found in the range 3-5 nm. The x-ray diffraction measurements showed that the nanoparticles have the structure of hexagonal phase. The broadening of XRD patterns indicate that the prepared CdS:Fe samples are nanostructures. The UV absorption results indicated that the doping increased optical band gap of nanoparticles which means the particle size decreased due to Fe doping. Also, effects of doping and capping agent concentration on the luminescence spectra of CdS:Fe nanoparticles investigated
Volume 9, Issue 2 (10-2010)
Abstract
In this research, ac measurements of copper phthalocyanine thin film using aluminium electrodes are investigated in the frequency range 102 to 105 Hz and within the temperature range frequency and the capacitance and dissipation factor(loss tangent) decrease with increasing relative importance of the hopping model and band theory in describing the film condution with regard to the operating conditions. It was observed that the band theory is dominant at high frequencies and high temperatures, whereas hopping model is dominant at low frequencies. The energy gap of CuPc was determined using dc measurements.
Volume 9, Issue 2 (10-2010)
Abstract
Zolachay river has an area about 960 square kilometer located in south-west of Salmas city. The evaluation of shape and drainage density of catchment area shows a dense catchment with high flood discharge and erosion potential. The texture variations and particle size growth are investigated at 84 locations in river catchment area. The particle size increases exponentially toward the river downstream. The results indicate that particle size growth is due to tributary entry and lithology changes. In overall view the river sediment particle size distribution shows bad sorting with positive skewness. It is used the trend of particle size mean and median for selecting the proper SDR method. Also the river suspension sediment loads estimated approximately 105 ton per day using the Yang method.
Volume 9, Issue 3 (10-2010)
Abstract
Several experiments have been performed during the last few decades to evaluate the responses of plants to enhanced solar UV radiation (UV-R) that may occur because of stratospheric ozone depletion. The objective of this study was to evaluate the effects of UV radiation on some anatomical and ultrastructural aspects of pepper plants (Capsicum longum L) in the greenhouse. Pepper plants were grown in a uniform environment and after 35 days they were exposed to UV-A and UV-C radiation for 15 and 8 days, respectively. The results indicated that the changes in root growth was not significant but the growth of shoot decreased in UV-R exposed plants and this reduction was significant in UV-C exposed plants. Leaf area was also reduced in UV-R exposed plants and this reduction was significant in UV-C exposed plants. The root diameter was not affected under UV treatment, but the stem diameter and leaf thickness were significantly increased in both UV-A and UV-C treatments. The number and size of stomata were also increased in UV-R exposed plants. At the ultrastructural level, it was found that the thylakoids of chloroplast were dilated and starch reduction was observed. UV treatment resulted in the formation of crystalline inclusion in the peroxisomes of the mesophyll cells. Formation of these crystals may be due to the increased activity of catalase, which is an antioxidant enzyme. The study shows that pepper plants are sensitive to UV-R and this finding provides insight into the structural and ultrastructural changes during UV exposure, and indicates the sensitivity of these plants to UV-C more than UV-A radiation.
Volume 9, Issue 3 (10-2010)
Abstract
Biosurfactants are products of broad range of microorganisms. These compounds are surface active. Glycolipids, Phospholipids & Fatty acids, Lipopeptids and Lipoproteins, Polymeric biosurfactants and Special Biosurfactants are main types of biosurfactants. Rhamnolipid is a type of Glycolipids that is produced by Pseudomonas aeruginosa. In the present paper, P. aeruginosa MM1011 was obtained from Persian Type Culture Collection (Biotechnology Center, IROST). The aim of this investigation was optimization of mineral salts medium with sugar beet molasses to produce rhamnolipid considering specific parameters. such as: C/N, Temperature, pH, shaking rate, and Inoculation size. Since P. aeruginosa is Suc.(-), it was mutated to be able to use the sucrose as carbon source. The molasses treated chemically, then used by the bacterium. The results assayed by phenol-sulfuric acid method, and crude oil emulsification capability. Results of ANOVA. Depicted results showd that the optimum conditions without molasses is: temp.:33˚c, pH 7, C/N:18, shaking rate: 200 rpm and inoculom: 2% in 96 hours and the best medium is 3M which contained sugar beet molasses. Further investigation proved that the best production temperature is 33°c when pH is 6.8, shaking rate: 200 rpm, C/N: 16, inoculom: 2%. Using the above mentioned factors, the obtained results showed that the produced rhamnose was 0.22 g/L (rhamnolipid = 0.66 g /L) and crude oil emulcification was 55.5 %.
Volume 9, Issue 4 (10-2010)
Abstract
Nickel is one of the essential elements (micronutrients) for plant growth. In this study, the effects of different concentrations of nickel, (0, 40, 80, 160, 320, 640 and 1280&mu M) and some environmental factors such as pH and Ca2+ concentration on the growth of seedlings of four wheat cultivars (Sardari, Zarrin, Alamout and C-73-20) were investigated. Moreover, the impact of high concentration of Ni on root sugar secretion has been assessed using sulphuric-phenol method .The results indicated that Alamout was more resistant than the other cultivars regarding to nickel stress. On the other hand, root and shoot tissues showed different growth responses to Ni and radical growth was more sensitive than shoot growth. Decreased pH increased the impact effect of nickel on shoot and root growth. Our study showed that increasing Ca2+concentration decreases Ni toxicity. Finally, Ni inhibited the leakage of soluble sugars from root tissue.
Volume 9, Issue 4 (10-2010)
Abstract
The effect of various CuCl2 concentrations at rosette stage on protein level, catalase and peroxidase activities of leaf and root of two canola cultivars were studied under greenhouse conditions. The experiment was conducted as factorial in completely randomized design with 4 replications and 4 treatments (0, 100, 300, and 500µM CuCl2). In general, protein concentration and catalaze and peroxidase activities were increased with increasing CuCl2 concentration. This enhance was more in PF cultivar than Hayola, and was more in root than leaf. Thus, it seems that PF cultivar has more ability in protein biosynthesis and antioxidant enzymes activation in compare with Hyola in stress conditions. Therefore, PF can be introduced as a cultivar with more tolerance to cupper stress, in compare with Hayola cultivar.
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Volume 9, Issue 4 (10-2010)
Abstract
The Ursolic Acid and Oleanolic Acid presented in apple peels have a potential antioxidant acivity. Antiprolifertive acivity of the triterpenoids against human liver cancer cells, breast cancer cells and colon cancer ells is evaluated. In this study, we have used Ursolic Acid and Oleanolic Acid which are predominant isolated triterpenoids of the apple peels.. The purpose of this study is to determine antimutation and anticarcinogen effect of Ursolic Acid and Oleanolic Acid against Sodium Azide mutagen substance by the use of Microsome and Ames test.
These substances were white powder and soluble in Acetone and bought from sigma company. The bacterium used in this test is a strain of Salmonella thyphimurium (TA100) that carries a selective mutation in its Histidine Operon. We also added Microsome to improve anticancer activity of this two triterpenoids. In this study, inhibition percentage from mutation was 83% for ursolic acid and 76.4 % for oleanolic acid in presence of Microsome ( and 77.6 % for Ursolic Acid and 69.8 % for Oleanolic Acid in absence of Microsome) . Therefore , presence of anti mutation Ursolic Acid and oleanolic acid along with mutagen substance, reduced quantity of back mutation and Inhibition over 40 % recommended as a powerful antimutation substance. Therefore, apple peel has large amount of active Phytochemicals, with Antimutation and Anticarcinogen activity and Ursolic Acid has more antimutation activity than Oleanolic acid
Volume 9, Issue 4 (10-2010)
Abstract
This study was performed to investigate the effects of ultraviolet light (UVC) on the third instar larvae of Drosophila melanogaster. To address such effects, double heterozygote larvae for two linked genes sepia and ebony (se e/++) were exposed to UV light at the wavelength of 254 nm in different exposure times (5-35 seconds). Our study showed that the UVC exposure induced a series of significant morphological abnormities in adult flies which had received radiation in their larval life-time. Short exposure times of UVC caused abnormalities in adult flies such as abdominal cuticular damages and abnormal legs and wings, but had no significant effect on the rate of gene recombination. Therefore, it seems the time of exposure which was used in this research affected some imaginal discs and histoblasts on the larvae.
Volume 9, Issue 4 (10-2010)
Abstract
Effect of salinity was studied on the growth, survival and blood biochemical variables of juvenile rainbow trout (Oncorhynchus mykiss (weighing 50.29 ± 4.61 g at water temperature 15±2 ˚C. Fourthy fish in three replicate were gradually acclimatized to salinities zero (control), 10, 20, 30 and 40 ppt for 10 days. The experiment was then run for 50 days using a commercial trout feed. The obtained results showed that with increasing in the salinity the growth factors of rainbow trout including (weight gain, daily growth rate, specific growth rate and feed conversion efficiency) decreased (P<0.05). At salinity above 20 ppt significant mortality occurred compared to control group (P<0.05). Also with increasing in salinity, the blood biochemistry including osmolality, chlorine, sugar, cortisol, tri-iodo thyronin(T3), and thyroxine [Tetra – iodo – thyronin (T4)] increased (P<0.05). Based on the results obtained it possible to grow the rainbow trout juvenile of about 50 g at the salinity up to 20 ppt, although the growth rate of the fish is less than that in the fresh water.
S Bodaghi, A Shahrezaee,
Volume 10, Issue 1 (3-2010)
Abstract
In this article, we compare two procedures for solving a parabolic inverse heat problem subject to the over specified boundary condition .The first procedure is obtained by introducing transformation of unknown function and solving transformed problem by finite difference method. And the second method based on trace-type functional (TTF) formulation is examined on the solving of considered problem. Some numerical examples are presented
Volume 10, Issue 1 (3-2010)
Abstract
مسائل لایۀ کرانهای، مدل ریاضی پدیدههای طبیعی و مسائل فیزیک و مهندسی هستند که در نقطه یا نقاطی که لایۀ کرانهای تشکیل میشود باید جوابهای مسئله را با تکنیکهای خاصی بررسی کرد تا جواب مسئله بهصورت یکنواخت و یکپارچه درآید. برای این مسئله ابتدا شرایط کافی برای وجود و عدم وجود تشکیل لایۀ کرانه ارائه میشود، سپس برای حالتی که در هر دو نقطه لایۀ کرانهای اتفاق میافتد، جواب تقریبی مسئله را با استفاده از روش بسطهای مجانبی سازگار شده در پنج مرحله بهصورت یکپارچه به دست میآوریم.
