Search

We report three-dimensional Mott variable-range hopping (3D Mott-VRH) transport of Sr2IrO4 epitaxial thin films, with a transition to Efros-Shklovskii variable-range hopping (ES-VRH) with increased misfit strain or isovalent doping. We have observed that the characteristic temperature of 3D Mott-VRH transport decreases under increased misfit strain, implying that the density of states near the Fermi energy is reconstructed. With further increased misfit strain (or doping with Ca or Ba ions), a crossover from the 3D Mott-VRH to ES-VRH transport takes place due to increased carrier localization by disorder, opening a Coulomb gap by increasing the effective electron-correlation. The results of magnetoresistance measurements also confirm that the disorder caused by misfit strain or isovalent doping plays an important role in the electronic transport of these Sr2IrO4 thin films. Our experimental observations propose that subtle external stimuli such as structural modifications can modulate the electronic properties of the relativistic Mott insulator, suggesting an unprecedented pathway for electronic device applications. [ABSTRACT FROM AUTHOR]

The initial establishment of rangeland species, especially in arid and semi-arid areas, is a significant issue for the improvement and development of rangelands and increasing their yield. In order to investigate the effects of seed priming on changes in yield of the Astragalus brachyodontus, the present study was carried out in the greenhouse with factorial design. Three treatments of hydro-priming (distilled water), osmopriming (Polyethylene Glycol with two levels of -0.4 and -0.8 MPa) and priming hormone (gibberellic acid) as the first factor, and three levels of deficit irrigation stress (100% of field capacity, 75% of field capacity and 50% of field capacity) were considered as the second factor and three populations (Zanjan, Qom and Khalkhal) as the third factor with three replications. The results showed that seed priming, deficit irrigation stress, populations and their interactions had a significant effect (p≤0.01) on all investigated traits. The soil water reduction caused a significant decrease in seedling germination percentage, stem length and weight, however, the root length increased and the root weight first increased and then decreased intensively. The maximum yield of height (11.0267 cm), root length (30.6467 cm), stem weight (1.1700 g) and root weight (1.3664 g) was related to Zanjan population in normal irrigation. The treatment of -0.4 MPa osmopriming had the highest values in root length (33.1556 cm), stem weight (1.2144 g) and root weight (1.4800 g). Generally, according to the present research, -0.4 MPa osmo-priming and priming hormone with gibberellic acid were introduced as treatments to improve the Astragalus brachyodontus species performance in the greenhouse under the severe deficit irrigation stress condition. This result can be considered to improving the establishment and performance of this native valuable forage, in breeding programs and rangeland development, to improve its initial establishment in deficit irrigation conditions. [ABSTRACT FROM AUTHOR]

Gross primary production is one of the key factors for understanding growing grassland conditions and rangeland monitoring. The present study aims to introduce an improved index based on the primary GDP and NDVI vegetation index of MODIS. In this regard, field operations were carried out in May, simultaneously with the growth of vegetation in the Rasin basin of Kermanshah province. In each of the types, reference areas were determined, and six (100-meter) transects were deployed in each of the representative points. Along each transect, five plots were placed at a distance of 20 meters, and a total of 84 transects and 420 plots were used in the field. Information such as rangeland type and actual fresh forage (AFY, kg/ha) were determined in the Rasin basin. In general, three types were identified in the field. Modified primary GDP data were calculated and validated with the measured data in the Rasin basin of Kermanshah province. The results showed that, in type 1, with R² equal to 0.77 Ss index of gross primary production of NDVI as an improved index, in type 2, Ss index of primary production of NDVI with R² 0.73, in type 3, Ss index of gross primary production NDVI with R² equal to 0.71, and finally, for the whole rangeland type, Ss index of gross primary production of NDVI with R² equal to 0.51 was determined as the improved index. The results also showed that the modified primary GDP data is an acceptable indicator for monitoring grasslands. The accuracy of estimating rangeland production based on the Ss index of gross primary production of NDVI was 80%. The statistical results of comparing the estimated values with field observations indicate the acceptable accuracy of statistical models in estimating production. Also, since MODIS data is available twice a day, the improved index can supply the real need for rangeland monitoring on a regional scale. [ABSTRACT FROM AUTHOR]

Amino acids have diverse roles in plant metabolism, and recently amino acid based fertilizers have been used largely in crop production systems. Despite most of these new fertilizers are formulated for foliar application; however, morphophysiological responses of crops to amino acids application have applicationnot yet been well documented. In the present study, foliar application of glycine or glutamine in different concentrations of 0 (distilled water), 250, 500, 1000 mg·L-1, as well as a treatment of 250 mg·L-1 glycine + 250 mg·L-1 glutamine were evaluated on growth of sweet basil (Ocimum basilicum L.) plants. The results showed that foliar application of glycine or glutamine at 1000 mg·L1 showed no improvement in comparison with control for all traits except for leaf Lascorbic acid concentration that showed the highest value under these amino acids treatments. However, foliar application of these amino acids at 250 and particularly 500 mg·L-1 showed promising effect on sweet basil growth. Plant shoot fresh and dry weight, leaf area, leaf SPAD value, and leaf chlorophyll content were improved by foliar application of 500 mg·L-1 glycine or glutamine in comparison with control plants. Foliar application of amino acids increased leaf nitrogen (glutamine 250 and 500 mg·L-1), potassium (glycine 250 mg·L-1), magnesium (glutamine 250 or 500 mg·L-1, glycine 250 mg·L-1, glycine + glutamine; 250 + 250 mg·L-1), iron (glycine and glutamine at 500 mg·L-1 and glutamine at 250 mg·L-1), and zinc (glycine and glutamine at 250 or 500 mg·L-1), whereas the increase in leaf nutrients caused by other treatments was not significantly different from control plants. Leaf calcium concentration was not changed by amino acid treatments. The results indicate that foliar application of moderate to low concentrations of glutamine or glycine can improve sweet basil growth. [ABSTRACT FROM AUTHOR]

This study was conducted to demonstrate the growth behavior of Aeluropus lagopoides, Desmostachya bipinnata, Halocnemum strobilaceum, Alhagi graecorum and Atriplex leucoclada in the Zaminsang rangelands of Hormozgan province during 2007 to 2010. Determination of the production and consumption were done by the individuals in medium size. In each year, five medium individual of plant were selected for all months of growing and grazing season in exclosure area for measuring the production and the same number in the grazing range considered for measuring the production residue and from difference between them, the consumption was identified. Results indicated that different years and months had significant effect on production and consumption of the study species (p<0.05). According to the obtained data from the experiment indicated that, the average production of five perennials species was 125.8 kg dry forage per hectare. The highest production rate was obtained from Halocnemum strobilaceum and Desmostachya bipinnata in amount of 52.9% and 22.9% of total forage production, respectively. The average consumption of the species was 32.4 kg dry forage per hectare. The highest consumption rate was dedicated to Halocnemum strobilaceum and Alhagi graecorum, with amount of 41.8% and 30.1% of total forage consumption, respectively. The highest production rate was obtained from 2008 with 162.7 kg dry forage per hectare which was 1.8 times higher than low-production in 2009. The highest consumption rate for all species was 35.7 kg dry forage per hectare in 2009. The highest forage production and consumption were obtained in May in all species during the years. [ABSTRACT FROM AUTHOR]

Aminochelate are organic-based chelate fertilizers with higher efficiency for agricultural applications. In the present study, foliar application of three organic-based chelate fertilizers, a macro-micro mixture and soil applied NPK were evaluated on French bean growth characteristics under open field in a calcareous soil. The results showed that plant growth, pod yield (79%) and pod quality were improved by application of chelate fertilizers. Growth parameters as plant height, number of leaves and lateral shoots, shoot dry weight, pod number and pod length were significantly increased by foliar application of the chelate fertilizers. The concentrations of nitrogen, potassium and iron in pods and above all in leaves were increased by foliar application of chelate fertilizers compared to control and soil applied NPK. Pod pH and TSS were not influenced by treatments; however, foliar application of the chelate fertilizers resulted in higher titratable acidity (40%), vitamin C (112%) and protein (35%) content of pods. The results indicate that organic-based chelate fertilizers can be effective safer alternatives for simple chemical salts in calcareous soils. [ABSTRACT FROM AUTHOR]

Tomato is a typical plant that has distinct response to different nitrogen forms in hydroponic culture. In addition, it is a well known susceptible plant to ammonium nutrition in hydroponic culture. However, its response to foliar application of nitrogen sources and N-forms has not been well investigated. In the present study, the growth, productivity and fruit quality of tomato was investigated under foliar application of nitrogen from different sources. Ammonium sulfate, urea and calcium nitrate with constant concentration of 100 mM N were weekly sprayed during four months under hydroponic culture system. A water spray treatment was considered as control. The results showed that vegetative growth parameters were significantly affected by N sources in different patterns. The factors such as plant height, leaf area, number of lateral shoots and shoot fresh and dry weight, as well as leaf nitrate reductase activity was significantly reduced by foliar application of ammonium sulfate and to less extent by urea, while there was improvement of these traits by foliar application of calcium nitrate compared to control. However, ammonium sulfate treated plants had the highest leaf SPAD value and leaf N concentrations. Plant fruiting pattern was also influenced by treatments, as ammonium sulfate spray reduced the fruit yield, and fruit vitamin C content, while it increased fruit TSS and titratable acidity. The highest value of yield and vitamin C was recorded in calcium nitrate sprayed plants. [ABSTRACT FROM AUTHOR]

This study was conducted under Ahvaz, Iran environmental condition during 2012 and 2013 growing seasons in order to investigate the influence of foliar application of potassium on some physiological and biochemical characteristics of three olive cultivars including ‘Mission', ‘Koroneiki' and ‘Dezfuli'. Potassium sulfate in different concentrations of 0, 1, and 2 g l-1 was sprayed twice on selected mature 10 year old trees; at 50 and 65 days after full bloom. Potassium sprays increased leaf chlorophyll content of all cultivars, leaf potassium content in ‘Mission' and ‘Koroneiki' cvs., fruit anthocyanin concentration of ‘Dezfuli' in two crop seasons. However, K treatments had no significant effect on leaf N and P content, fruit K and P content in all studied cultivars. Fruit soluble carbohydrates increased by foliar application of potassium in ‘Koroneiki' and ‘Dezfuli' cultivars in the second year of study. Stem water potential and leaf stomatal conductance were significantly affected by cultivar and K treatments during the two years. Our findings showed that foliar application of potassium resulted in the decrease of stomatal conductance of ‘Koroneiki' and ‘Dezfuli' in two crop seasons. Based on the results, it can be concluded that the studied cultivars differently respond to K treatments during the two crop seasons and foliar potassium application could have a positive impact on leaf chlorophyll, leaf potassium, fruit soluble carbohydrates and fruit anthocyanins in olive cultivars. [ABSTRACT FROM AUTHOR]

We report that epitaxial Sr2IrO4 thin-films can be selectively grown using pulsed laser deposition (PLD). Due to the competition between the Ruddlesden-Popper phases of strontium iridates (Srn+1IrnO3n+1), conventional PLD methods often result in mixed phases of Sr2IrO4 (n=1), Sr3Ir2O7 (n=2), and SrIrO3 (n=∞). We have discovered that reduced PLD plume dimensions and slow deposition rates are the key for stabilizing pure Sr2IrO4 phase thin-films, identified by realtime in-situ monitoring of their optical spectra. The slow film deposition results in a thermodynamically stable TiO2\\SrO\IrO2\SrO\SrO configuration at an interface rather than TiO2\\SrO\SrO\IrO2\SrO between a TiO2-terminated SrTiO3 substrate and a Sr2IrO4 thin film, which is consistent with other layered oxides grown by molecular beam epitaxy. Our approach provides an effective method for using PLD to achieve pure phase thin-films of layered materials that are susceptible to several energetically competing phases. [ABSTRACT FROM AUTHOR]

Metal electrodes are a universal element of all electronic devices. Conducting SrRuO3 (SRO) epitaxial thin films have been extensively used as electrodes in complex-oxide heterostructures due to good lattice mismatches with perovskite substrates. However, when compared to SRO single crystals, SRO thin films have shown reduced conductivity and Curie temperatures (TC), which can lead to higher Joule heating and energy loss in the devices. Here, we report that high-quality SRO thin films can be synthesized by controlling the plume dynamics and growth rate of pulsed laser epitaxy (PLE) with real-time optical spectroscopic monitoring. The SRO thin films grown under the kinetically controlled conditions, down to ca. 16 nm in thickness, exhibit both enhanced conductivity and TC as compared to bulk values, due to their improved stoichiometry and a strain-mediated increase of the bandwidth of Ru 4d electrons. This result provides a direction for enhancing the physical properties of PLE-grown thin films and paves a way to improved device applications. [ABSTRACT FROM AUTHOR]

One hundred female Markhoz goats (42±5 kg) were used to investigate the 'male effect' on estrous synchronization and reproductive characteristics of female goat during the breeding season. This was carried out in three separate experiments. In the first experiment, forty female goats were used in 4 groups with different distance from the male goats (i.e. source of pheromone secretion); A1 (1 meter), A2 (12.5 meters), A3 (25 meters) and A4 (50 meters). In the second experiment, thirty female goats were synchronized using CIDR in three groups in the presence or absence of male goats; B1 (the presence of male goat with females during synchronization), B2 (sudden introducing of male goat to females goat during the time of removal of CIDR) and B3 (no male goat during synchronization). In the third experiment, thirty female goats were used in 3 groups; C1 (male goat permanently was presented near to the females during the experiment), C2 (sudden introducing of male to females) and D or control group (no male before mating). The results showed the effect of male goat on estrous synchronization, causing reproductive cycles in early breeding season and increasing incidence of estrous (P<0.05). The male effect improved fertility and kidding rates (P<0.05). Male effect was more pronounced when the distance of unlike sexes decreased (P<0.01). Male effect was also more effective, with sudden introducing of male to female goat (P<0.01). The male effect was more efficient when compared with synchronized female by CIDR in onset of estrous (P<0.05), and increased serum estrogen concentration in the follicular phase (P<0.05). [ABSTRACT FROM AUTHOR]