Space-charge limited conduction in epitaxial chromia films grown on elemental and oxide-based metallic substrates

We study temperature dependent (200 – 400 K) dielectric current leakage in high-quality, epitaxial chromia films, synthesized on various conductive substrates (Pd, Pt and V2O3). We find that trap-assisted space-charge limited conduction is the dominant source of electrical leakage in the films, and that the density and distribution of charge traps within them is strongly dependent upon the choice of the underlying substrate. Pd-based chromia is found to exhibit leakage consistent with the presence of deep, discrete traps, a characteristic that is related to the known properties of twinning defects in the material. The Pt- and V2O3-based films, in contrast, show behavior typical of insulators with shallow, exponentially-distributed traps. The highest resistivity is obtained for chromia fabricated on V2O3substrates, consistent with a lower total trap density in these films. Our studies suggest that chromia thin films formed on V2O3 substrates are a promising candidate for next-generation spintronics

Genetic diversity, population structure, and genome‑wide association study for the flowering trait in a diverse panel of 428 moth bean (Vigna aconitifolia) accessions using genotyping by sequencing

Background Moth bean (Vigna aconitifolia) is an underutilized, protein-rich legume that is grown in arid and semiarid areas of south Asia and is highly resistant to abiotic stresses such as heat and drought. Despite its economic importance, the crop remains unexplored at the genomic level for genetic diversity and trait mapping studies. To date, there is no report of SNP marker discovery and association mapping of any trait in this crop. Therefore, this study aimed to dissect the genetic diversity, population structure and marker-trait association for the flowering trait in a diversity panel of 428 moth bean accessions using genotyping by sequencing (GBS) approach. Results A total of 9078 high-quality single nucleotide polymorphisms (SNPs) were discovered by genotyping of 428 moth bean accessions. Model-based structure analysis and PCA grouped the moth bean accessions into two subpopulations. Cluster analysis revealed accessions belonging to the Northwestern region of India had higher variability than accessions from the other regions suggesting that this region represents its center of diversity. AMOVA revealed more variations within individuals (74%) and among the individuals (24%) than among the populations (2%). Marker-trait association analysis using seven multi-locus models including mrMLM, FASTmrEMMA FASTmrEMMA, ISIS EM-BLASSO, MLMM, BLINK and FarmCPU revealed 29 potential genomic regions for the trait days to 50% flowering, which were consistently detected in three or more models. Analysis of the allelic effect of the major genomic regions explaining phenotypic variance of more than 10% and those detected in at least 2 environments showed 4 genomic regions with significant phenotypic effect on this trait. Further, we also analyzed genetic relationships among the Vigna species using SNP markers. The genomic localization of moth bean SNPs on genomes of closely related Vigna species demonstrated that maximum numbers of SNPs were getting localized on Vigna mungo. This suggested that the moth bean is most closely related to V. mungo. Conclusion Our study shows that the north-western regions of India represent the center of diversity of the moth bean. Further, the study revealed flowering-related genomic regions/candidate genes which can be potentially exploited in breeding programs to develop early-maturity moth bean varieties

Functionalized multiwalled carbon nanotubes based hydrogen gas sensor

Carbon nanotubes (CNTs) are extremely sensitive to environmental gases. Detection of H-2 gas at room temperature with fast response and recovery time is still a challenge. Here, we report that 0.05% H-2 gas at room temperature can be detected using acids functionalized multiwalled carbon nanotubes (F-MWCNTs). F-MWCNTs showed faster response to H-2 gas as compared to pristine multiwalled carbon nanotubes (P-MWCNTs). The effect of functionalization on the P-MWCNTs structure and their electrical properties are investigated using different techniques. The calculated crystallite size of the acids treated nanotubes from the Raman spectra is found to decrease to 14.6 nm as compared to 15.2 nm for the pristine. Also, due to attchements of functional groups on the nanotubes, the interplanar size of F-MWCNTs is increased, as identified from high resolution transmission electron microscopy (HR-TEM) and the X-ray diffraction (XRD) analysis. The presence of functional groups at the nanotubes walls after acids treatments is confirmed by fourier transform infrared (FTIR) spectra. Furthermore, the current carrying capacity of F-MWCNTs is found to increase to 35 mA from 49 mu A at low sweep voltage. It is also observed that, the recovery time of F-MWCNTs sensor decreases to 100 s for 0.05% of H-2 gas as compared to 190s for the P-MWCNTs. (C) 2013 Elsevier B.V. All rights reserved

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Not AvailableThe poor nitrogen use efficiency (NUE) in crops increases input costs and environmental problems. Selection of efficient cultivar and using cultivar-specific nitrogen rate are important strategies to improve NUE. A three-year field experiment was conducted to assess yield and NUE of three wheat cultivars (WH-147, Raj-1482, PBW-343) under six levels of N (N0, N40, N60, N80, N100 and N120 kg ha-1) in hot arid conditions at Rajasthan, India. The cultivar, nitrogen rate, and cultivar 9 nitrogen rate effects were detected significant for growth, yield components, yield and NUE. PBW-343 had 5 and 18 % higher yield as compared to Raj-1482 and WH-147, respectively. Application of N enhanced growth, yield components, and yield. Averaged over cultivars and years, the grain yield with N40, N60, N80, N100, and N120 was 32, 78, 118, 133, and 137 % higher as compared to N0. Response to N rates was cultivar specific; PBW-343 had the greatest yield with N100 and N120, whereas at lower N rates (N0, N40) WH-147 and Raj-1482 had higher yield as compared to PBW-343. The PBW-343 had 45–48 % greater agronomic, and 21–22 % greater apparent recovery efficiencies of N than other cultivars. Results suggest that selection of suitable cultivar and adjusting cultivar –specific N application rates is vital for optimizing grain yield and NUE for wheat crops.Not Availabl

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Not AvailableBiophysical models predict the behavior of the land use system in physical terms such as crop yields, environmental effects, and effect on management. Oryza 2000 model Is an eco-physlologlcal crop model to simulate the growth and development of a rice crop in situations of potential production, water limitations, and nitrogen limitations. This paper reports on the calibration and validation of the model using Independent data sets of kharif rice crop. Data are originated from the nitrogen balance experiment conducted by Directorate of Rice Research (DRR), Hyderabad during 2001 .The calibration of the model was performed by deriving the crop growth parameters for DRRHl and Vikas varieties. Results show that there was overestimation of Leaf Area Index (LAl) in all our observations and there was slight overestlmation between simulated and observed weights of the total aboveground dry matter (WAGT and WAGT_OB5) of DRRH1 (13.7%) and Vikas (10.5%) varieties. At maturity date, with respect to grain yield (WRR14) parameter, model has shown slight overestimation with average of observed values of DRRHI (9.5%) and Vlkas (4.3 %). But in each case one of the replications of observed values very nearer to simulated values. Model simulations can be further improved by calibrating other parameters of crop. Hence, calibration to the model at different levels with more intensive field experimental data will Improve the performance of the model and it can be effectively used for different management practices for irrigated rice grown in dry season or wet season.Not Availabl

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Edited lectures on Arid HorticultureEdited lectures on Arid HorticultureNot Availabl

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Not AvailableDifferent irrigation methods and mulching materials were tested at CAZRI, RRS, Bikaner during 2009 and 2010 on okra crop under hot arid conditions. Irrigation methods viz., drip (I1) and furrow (I2) and mulching materials viz., plastic (M1), hessian cloth (M2), indigenous materials (M3) and no mulch (M4) were evaluated in Split plot design with three replications using the okra cv. Varsha Uphar. Among the various treatments drip irrigation and plastic mulch alone and their interaction resulted in maximum plant height, number of branches, number of fruits per plant, fruit weight, fruit yield per plant and yield per hectare. Drip irrigation increased 13.5 percent and 12.9 percent fruit yield/ha over furrow method in 2009 and 2010, respectively. Plastic mulch recorded the highest fruit yield/ha in both the year which was 10.2, 17.7 and 32.7 percent higher compared to hessian cloth, indigenous material and no mulch, respectively.Not Availabl