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Plants infected by arbuscular mycorrhizal fungi can tolerate and recover more rapidly from different biotic and abiotic stresses such as soil water deficits than uninfected plants. Thereby study of the dominant mycorrhiza species in the fields under drought stresses is very useful for increasing crop productivity in these conditions and promising for biological fertilizer production in the future. The objective of this research was to study the variations in morphological and molecular diversity of arbuscular mycorrhizal fungi (AMF) and identification of dominant AMF in wheat and barley fields of some arid and semi arid regions of Iran. For this purpose, about 66 samples containing root and rhizospher soils of wheat and barley plants were collected from some arid and semi arid regions of Iran (Isfahan, Tehran, Ghazvin, Arak, Tabriz). After trap culture of observed mycorrhiza in the samples, they were identified using morphological and molecular techniques. The ITS-rDNA of AMF in root DNA extracts of wheat and barley amplified with the primer pair LSU-Glom1/SSU-Glom1 as specific primer for AMF and ITS4/ITS5 as general primers in the first and second reactions of PCR (nested PCR), respectively. Aliquots of the positive second PCR products were cloned. Positive colonies were digested with Taq1. The restriction fragment length polymorphism (RFLP) patterns of digested samples were compared and 1-3 representatives of each pattern at each cloning reaction were sequenced. Morphological and molecular diversity of AMF showed that more than 90% AMF observed in the regions belong to genus Glomus which coordinates with morphological studies and followed by G. intraradices. Also these studies confirmed presence of following species in some regions: G. fasciculatum, G. geosporum, G. sinosum, G. constrictum, G. macrocarpum and Glomus sp. and Acaulospora (Acaulospora sp.). It is important to note that the species G. etunicatu and G. dimorphicum were not detected in the morphological studies and Glomus mosseae was the most dominant AMF species in the all studied regions.

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Using adaptive minimum variance beamforming (MV) results in a significant improvement in image resolution, but it’s success in enhancing contrast has not yet been satisfactory. In some researches, eigenspace-based minimum variance beamforming (EIBMV) method has been applied to medical ultrasound imaging system, so that it has improved image contrast while maintaining its resolution. In this paper we apply another eigenspace-based beamforming called eigencanceler (EC) and show it can yield more satisfactory results. However EC needs the noise – interference covariance matrix, whereas the MV and EIBMV use the data covariance matrix. So an altered EC is proposed for the ultrasound imaging. In this method, while canceling the desired signal does not occur, any weight vector is considered to lie in the noise subspace, the subspace orthogonal to the dominant eigenvectors. Otherwise, the weight vector is defined uniformly. Simulation results show the superiority of this method over the MV and EIBMV methods in the contrast aspect. Moreover, the method is more robust against the sound speed errors and can obtain images with better definition of boundaries.    

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The impact of land use intensity on the abundance and diversity of arbuscular mycorrhizal fungi (AMF) was investigated at six land use types viz., natural forest, grassland, acacia plantations, cardamom plantations, coffee plantations and paddy fields in the Niligiri Biosphere of the Western Ghats in South India. There was no significant difference in AMF root colonization in different land use types during pre-monsoon but there was a significant difference in AMF root infection ratings between different land use types during post-monsoon season, where it was higher in natural forests and grasslands. The AMF spore density and infective propagules were significantly higher in grasslands and acacia plantations compared to all other land use types during both seasons. Except for paddy fields, the spore density and number of infective propagules were higher in post-monsoon season compared to pre-monsoon season in other land use types. The numbers of AMF species identified were 56 during pre-monsoon and 67 species during post-monsoon season suggesting seasonal variations in diversity. During both seasons Glomus fasciculatum was recorded in maximum number of sampling points across the landscape followed by G. geosporum during pre-monsoon and G. mosseae during post-monsoon season. The species diversity was highest in natural forests and grasslands as compared to other land use types in both seasons. The species richness index for AMF was highest in natural forests and least in paddy fields during both study periods. The sand content, bulk density, total N, organic C, alkaline and acid phosphatases positively correlated with AMF activity while clay, silt, K, total P and available P were negatively correlated.

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The nitrogen (N) nutrition, crop yield, and responses of wheat to arbuscular mycorrhizal fungi (AMF) were tested in an experimental field under free-air ozone concentration [O₃] enrichment (FACE) conditions. The experiment included three treatments: ambient [O₃] (Ambient), elevated [O₃] (FACE, targeted at ambient [O₃]×1.5), and elevated [O₃] inoculated with an AMF consortium consisting of several Glomus species (FACE+AMF). AMF inoculation responsiveness of wheat was estimated by comparing plants grown in unsterilized soil inoculated with the exogenous AMF and in untreated soil containing indigenous AMF. Compared with the Ambient, relatively higher N contents but lower shoot biomasses of wheat plants were observed in the FACE treatment without AMF inoculation from the tillering stage in February and heading stage in April, respectively, which significantly (P< 0.05) decreased grain yield by 28% at harvest in June. Under the FACE condition, compared with the non-inoculated treatment, AMF inoculation significantly (P< 0.05) increased root colonization rates both at the tillering stage and heading stage, and also significantly (P< 0.05) increased shoot biomass at the heading stage and, hence, significantly (P< 0.05) increased grain yield by 40% at harvest. However, AMF inoculation significantly (P< 0.05) decreased total N content in wheat shoots at the tillering stage, suggesting that AMF consortia may enhance plant tolerance to elevated [O₃] by elevating root colonization rate rather than plant total N content at early growing stages.

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In recent years the use of metallic bipolar plates for fuel cells is considered. Several studies have been conducted on the various methods of forming these plates. Most of this research has been done on the serpentine flow fields. While in some cases that the pressure drop is important factor, the pin-type flow fields shows good performance. In this research, hydroforming of metallic bipolar plates with circular pin-type pattern from stainless steel 304 with 0.11mm thickness is investigated experimentally and numerically. For this purpose, the effect of geometrical parameters such as the die wall angle, the die chamfer dimension, the depth-to-width ratio of the die, and forming pressure on the profiles, filling percent, thickness distribution and thinning percent of the formed parts are investigated. In this regard, two dies with wall angle of 0 and 15 degree were prepared. Then experimental tests were done at different pressures. After performing the required tests, the results show that the die wall angle leads to a more uniform thickness distribution and higher precision of the parts profile. Also the suitable range of die geometrical parameters was determined.