The Impact of El Niño/Southern Oscillation on Hydrology and Rice Productivity in the Cauvery Basin, India: Application of the Soil and Water Assessment Tool

AbstractThis study was performed to further understanding of the variations in hydrology and rice crop productivity during different El Niño/Southern Oscillation (ENSO) events in the Cauvery River Basin of Tamil Nadu, India using the Soil and Water Assessment Tool (SWAT). The entire Cauvery Basin was divided into 301 sub-basins and further subdivided into 3,601 Hydrological Response Units (HRU). Based on the National Oceanic and Atmospheric Administration (NOAA) official website, information on El Niño (1972, 1982, 1987, 1991, 1997, 2002 and 2004) and La Niña (1970, 1971, 1973, 1974, 1975, 1988, 1998, 1999 and 2000) years were obtained. The SWAT model was continuously run from 1970 to 2008, and a composite for El Niño, La Niña and normal years was constructed to understand their influence on hydrology and rice crop productivity in the study area. From the analysis, it was clear that an El Niño episode is correlated with rainfall, hydrology and rice productivity in the Cauvery river basin. The validation of the SWAT model indicated the capability of SWAT to accurately predict stream flow and rice productivity. It was evident from the investigation that the quantum of rainfall was more during El Niño years with high inter-annual rainfall variability (809.3mm to 2,366mm) compared with La Niña and normal years. As a result, the soil water recharge, including percolation and soil water availability in the surface layers, was increased in the El Niño years. Simulated rice productivity over 39 years in the Cauvery Basin ranged between 1,137 and 7,865kgha−1 with a mean productivity of 3,955kgha−1. The coefficient of variation in rice productivity was higher during La Niña (21.4%) years compared with El Niño (14.7%) and normal years (14.6%). The mean rice productivity was increased in both El Niño and normal years, indicating the possibility of higher yields than those in La Niña years. An analysis of the hydrological data and rice productivity showed that the risk of failure was low during El Niño years compared with normal or La Niña years. This behavior could be utilized for forecasting rice crop productivity under different ENSO conditions and can provide information for policy makers when deciding on water allocation and import / export policies

Non-reactive scattering of N2 from the W(110) surface studied with different exchange–correlation functionals

8 páginas, 8 figuras, 1 tabla.-- El Pdf del artículo es la versión post-print.The non-reactive scattering of N2 from the W(110) surface is studied with six dimensional (6D) classical dynamics and two distinct potential energy surfaces (PES). Here, we use the PESs calculated with density functional theory and two different exchange–correlation functionals, the PW91 [J. E. Perdew et al., Phys. Rev. B, 1992, 46, 6671] and the RPBE [B. Hammer et al., Phys. Rev. B, 1999, 59, 7413]. By analyzing the final rotational state and angular distributions, we extract information on the characteristics of the two PESs in the 6D configurational space. Comparison of the theoretical results with the available experimental data provides detailed information on the validity of each functional. In general, the PW91 PES is more corrugated than the RPBE one in all the configurational space, meaning that there is a stronger dependence of the potential energy on the molecular orientation and position over the surface unit cell. Furthermore, we find that the larger corrugation and the less repulsive character exhibited by the PW91 PES seems to be realistic at distances above the chemisorption well. In contrast, the less corrugated RPBE PES performs better in the region below the chemisorption well.This work has been supported in part by the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. IT-366-07) and the Spanish Ministerio de Ciencia e Innovación (Grant No. FIS2010-19609-C02-02).Peer reviewe

The AgMIP Coordinated Climate-Crop Modeling Project (C3MP): Methods and Protocols

Climate change is expected to alter a multitude of factors important to agricultural systems, including pests, diseases, weeds, extreme climate events, water resources, soil degradation, and socio-economic pressures. Changes to carbon dioxide concentration ([CO2]), temperature, andwater (CTW) will be the primary drivers of change in crop growth and agricultural systems. Therefore, establishing the CTW-change sensitivity of crop yields is an urgent research need and warrants diverse methods of investigation. Crop models provide a biophysical, process-based tool to investigate crop responses across varying environmental conditions and farm management techniques, and have been applied in climate impact assessment by using a variety of methods (White et al., 2011, and references therein). However, there is a significant amount of divergence between various crop models’ responses to CTW changes (R¨otter et al., 2011). While the application of a site-based crop model is relatively simple, the coordination of such agricultural impact assessments on larger scales requires consistent and timely contributions from a large number of crop modelers, each time a new global climate model (GCM) scenario or downscaling technique is created. A coordinated, global effort to rapidly examine CTW sensitivity across multiple crops, crop models, and sites is needed to aid model development and enhance the assessment of climate impacts (Deser et al., 2012)..

The nature of interfacial binding of imidazole and carbene ligands with M20 nanoclusters (M = Au, Ag and Cu) - a theoretical study

To inspire more exciting developments in the design and advances of self-assembled monolayers (SAMs), the fundamental understanding of the nature of interaction between metal nanoparticles and certain functional groups is very crucial. In this work, the interactions of imidazole based organic ligands with metal clusters (M) were analyzed by using quantum theory of atoms in molecules (QTAIM) calculations and energy decomposition (EDA) techniques based on the orbitals optimized by density functional theory method (DFT). Imidazole (IMI) and carbene ligands (a-NHC and n-NHC) were considered for their interaction on the apex and face center position of the three different coinage metal clusters Au, Ag and Cu. The adsorption energies indicated the following behaviour in those complexes: (1) ligands adsorbed on the apex-A position of M clusters are more stable and less reactive, (2) the chemical stability of the carbene ligands is high, and (3) of the two NHCs considered here, our findings show a higher interfacial binding strength for a-NHC with M surfaces. Natural population analysis showed the charge transfer from imidazole to M with N-M coordination bonding and the existence of strong C-M covalent bonding for carbene-n,a-NHC-M-complexes. QTAIM calculations again confirmed the covalent interactions in the latter complexes. Furthermore, energy decomposition analyses were performed to obtain the energetic properties of bonding for all the complexes.K. R. G acknowledges the support by CSIC under JAE-DOC program 'Junta para la Ampliacion de Estudios cofinanciada por el FSE, and in part, by the Basque Departamento de Educacion, Universidades e Investigacion, the University of the Basque Country UPV/EHU (Grant No. IT-366-07), the Spanish Ministerio de Ciencia e Innovación (Grant No. FIS2010-19609-C02-02).Peer Reviewe

Suitability of amorphous TiO2 nanoparticles as a photoelectrode in dye sensitized solar cells: A DFT-TDDFT study

Ab-initio calculations of nano-sized (∼1 nm) amorphous-TiO2 cluster and dye molecules (N3 and N719) have been carried out. Optimized structures of amorphous cluster and dye molecules have been obtained via molecular dynamics (MD) and density functional theory (DFT) calculations, respectively. The lowest excited state energies of the TiO2 cluster and the dye molecules have been obtained using time-dependent DFT. The calculations show that HOMO-LUMO gap and singlet-singlet excited state energies for amorphous cluster are very similar to that of a crystalline TiO2 cluster. Our calculations also show that the energy levels of the molecular dyes are well aligned with those of the amorphous cluster. © 2013 Elsevier B.V. All rights reserved.K.R.G acknowledges the following support (a) CSIC under JAE-DOC program ‘Junta para la Ampliación de Estudios’ cofinanciada por el FSE, (b) the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. IT-366-07) and (c) the Spanish Ministerio de Ciencia e Innovación (Grant No. FIS2010-19609-C02-02).Peer Reviewe

Non-reactive scattering of N2 from the W(110) surface studied with different exchange–correlation functionals

8 páginas, 8 figuras, 1 tabla.-- El Pdf del artículo es la versión post-print.The non-reactive scattering of N2 from the W(110) surface is studied with six dimensional (6D) classical dynamics and two distinct potential energy surfaces (PES). Here, we use the PESs calculated with density functional theory and two different exchange–correlation functionals, the PW91 [J. E. Perdew et al., Phys. Rev. B, 1992, 46, 6671] and the RPBE [B. Hammer et al., Phys. Rev. B, 1999, 59, 7413]. By analyzing the final rotational state and angular distributions, we extract information on the characteristics of the two PESs in the 6D configurational space. Comparison of the theoretical results with the available experimental data provides detailed information on the validity of each functional. In general, the PW91 PES is more corrugated than the RPBE one in all the configurational space, meaning that there is a stronger dependence of the potential energy on the molecular orientation and position over the surface unit cell. Furthermore, we find that the larger corrugation and the less repulsive character exhibited by the PW91 PES seems to be realistic at distances above the chemisorption well. In contrast, the less corrugated RPBE PES performs better in the region below the chemisorption well.This work has been supported in part by the Basque Departamento de Educación, Universidades e Investigación, the University of the Basque Country UPV/EHU (Grant No. IT-366-07) and the Spanish Ministerio de Ciencia e Innovación (Grant No. FIS2010-19609-C02-02).Peer reviewe

An interpretation of the absorption and emission spectra of the gold dimer using modern theoretical tools

The excited states of the gold dimer have been investigated using modern theoretical tools including the multiconfigurational exact molecular mean-field intermediate Hamiltonian Fock-space Coupled Cluster, X2Cmmf-IHFSCC, and the complete active space self-consistent field followed by second order perturbation theory, CASSCF/CASPT2. The computed optically active transitions have been benchmarked against the available experimental data and compared with time-dependent density functional theory, TDDFT, results, both in the two- and four-component schemes. We explored in great detail several spectroscopic properties such as bond lengths, potential energy surfaces (PES), vibrational frequencies and vibrational progressions of the ground and low-lying excited states. Our data show excellent agreement with the experimental measurements and present a significant improvement compared to previous ab initio calculations. They also permit a detailed investigation of the intriguing a ← X and A′ ← X experimental bands that, according to our calculations, show an avoided energy level crossing. The location of this crossing is critical for a correct estimation of the vibrational progression and oscillator strengths of these two states. Moreover, among the exchange-correlation (xc) potentials, the SAOP gives the best excitation energies, followed by the hybrid B3LYP functional. Pure functionals like BLYP give by far the worst results. This journal is © the Owner Societies 2012.I.I. would like to thank the Minister of Science and Innovation for granting a Juan de la Cierva Fellowship. I.I., F.R. and J.M.U would like to thank the Eusko Jaurlaritza (GIC 07/85 IT-330-07) for financial support and the Spanish Office for Scientific Research (CTQ2011-27374). The work of M.D.M. on the gold dimer is supported by the National Science Foundation under grant No. CHE-0808984. K.R.G. acknowledges the support by CSIC under the JAE-DOC program Junta para la Ampliacion de Estudios co-financed by FSE, and in part, by the University of the Basque Country UPV/EHU (Grant No. IT-366-07), the Spanish Ministerio de Ciencia e Innovacion (Grant No. FIS2010-19609-C02-02).Peer Reviewe