630 research outputs found

    Optimizing chlorophyll meter (SPAD) reading to allow efficient nitrogen use in rice and wheat under rice-wheat cropping system in eastern India

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    Conventional agricultural practices that rely heavily on blanket fertilizer recommendation, eventually leading to deteriorated partial factor productivity and N use efficiency. We investigated the effect of SPAD-based N-management on productivity and N use efficiency of rice and wheat in eastern India. Here, in the experiment three SPAD thresholds (34, 36 and 38 in rice and 38, 40 and 42 in wheat) using three N levels (15, 25 and 35 kg N ha−1) in split were incorporated as real-time N management (RTNM), one fixed-time N management (FTNM), farmers’ fertilizer practice (FFP) and control (No fertilizer) were introduced in wet and dry seasons for rice and wheat, respectively, during the years 2010 to 2012. Topdressing with 25 kg N ha−1 at medium SPAD (S36 in rice and S40 in wheat) increased soil N availability, leaf N content and grain yield of rice (5215 kg ha−1) and wheat (4483 kg ha−1) over the grain yield recorded under a low rate of N topdressing at low SPAD. While saving 33.3% N in rice and 18.8% N in wheat, the agronomic N use efficiency (58.5% in both rice and wheat) and nitrogen recovery efficiency (32.2% in rice and 15.1% in wheat) can be increased when compared with conventional FTNM. The SPAD-based management strategy showed great promise in efficient management of N fertilizer, and we estimated the optimal SPAD threshold for rice and wheat as 37.5 and 41.8, respectively

    Heisenberg uniqueness pairs on the Euclidean spaces and the motion group

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    In this article, we consider Heisenberg uniqueness pairs corresponding to the exponential curve and surfaces, paraboloid, and sphere. Further, we look for analogous results related to the Heisenberg uniqueness pair on the Euclidean motion group and related product group

    Heisenberg uniqueness pairs on the Euclidean spaces and the motion group

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    In this article, we consider Heisenberg uniqueness pairs corresponding to the exponential curve and surfaces, paraboloid, and sphere. Further, we look for analogous results related to the Heisenberg uniqueness pair on the Euclidean motion group and related product group

    R-parity-violating SUSY and CP violation in B --> phi K_s

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    Recent measurements of CP asymmetry in B --> phi K_S appear to be inconsistent with Standard Model expectations. We explore the effect of R-parity-violating SUSY to understand the data.Comment: Equations corrected. Conclusions unchanged. Latex, 6 pages, one fi

    Realistic Anomaly Mediation with Bulk Gauge Fields

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    We present a simple general framework for realistic models of supersymmetry breaking driven by anomaly mediation. We consider a 5-dimensional "brane universe" where the visible and hidden sectors are localized on different branes, and the standard model gauge bosons propagate in the bulk. In this framework there can be charged scalar messengers that have contact interactions with the hidden sector, either localized in the hidden sector or in the bulk. These scalars obtain soft masses that feed into visible sector scalar masses at two loop order via bulk gauge interactions. This contribution is automatically flavor-blind, and can be naturally positive. If the messengers are in the bulk this contribution is automatically the same order of magnitude as the anomaly mediated contribution, independent of the brane spacing. If the messengers are localized to a brane the two effects are of the same order for relatively small brane spacings. The gaugino masses and A terms are determined completely by anomaly mediation. In order for anomaly mediation to dominate over radion mediation the radion must be is stabilized in a manner that preserves supersymmetry, with supergravity effects included. We show that this occurs in simple models. We also show that the mu problem can be solved by the vacuum expectation value of a singlet in this framework.Comment: 16 pages, LaTeX2e, no figure

    Mutual influence of structural distortion and superconductivity in systems with degenerate bands

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    The interplay between the band Jahn-Teller distortion and the superconductivity is studied for the system whose Fermi level lies in two-fold degenerate band. Assuming that the lattice distortion is coupled to the orbital electron density and the superconductivity arises due to BCS pairing mechanism between the electrons, the phase diagram is obtained for different doping with respect to half-filled band situation. The coexistence phase of superconductivity and distortion occurs within limited range of doping and the distortion lowers the superconducting transition temperature TcT_c. In presence of strong electron-lattice interaction the lattice strain is found to be maximum at half-filling and superconductivity does not appear for low doping. The maximum value of TcT_c obtainable for an optimum doping is limited by the structural transition temperature TsT_s. The growth of distortion is arrested with the onset of superconductivity and the distortion is found to disappear at lower temperature for some hole density. Such arresting of the growth of distortion at TcT_c produces discontinuous jump in thermal expansion coefficient. The variation of strain with temperature as well as with doping, thermal expansion coefficient, the TcT_c vs δ\delta behaviour are in qualitative agreement with recent experimental observations on interplay of distortion and superconductivity in cuprates.Comment: 15 pages Revtex style, 9 figures available on request to first Autho

    Symmetry Properties on Magnetization in the Hubbard Model at Finite Temperatures

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    By making use of some symmetry properties of the relevant Hamiltonian, two fundamental relations between the ferromagnetic magnetization and a spin correlation function are derived for the d(=1,2,3)d (=1,2,3)-dimensional Hubbard model at finite temperatures. These can be viewed as a kind of Ward-Takahashi identities. The properties of the magnetization as a function of the applied field are discussed. The results thus obtained hold true for both repulsive and attractive on-site Coulomb interactions, and for arbitrary electron fillings.Comment: Latex file, no figur

    Coupled channel description of 16O+142,144,146Nd scattering around the Coulomb barrier using a complex microscopic potential

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    Angular distributions of elastic scattering and inelastic scattering from 2+ 1 state are measured for 16O+142,144,146Nd systems at several energies in the vicinity of the Coulomb barrier. The angular distributions are systematically analyzed in coupled channel framework. Renormalized double folded real optical and coupling potentials with DDM3Y interaction have been used in the calculation. Relevant nuclear densities needed to generate the potentials are derived from shell model wavefunctions. A truncated shell model calculation has been performed and the calculated energy levels are compared with the experimental ones. To simulate the absorption, a 'hybrid' approach is adopted. The contribution to the imaginary potential of couplings to the inelastic channels, other than the 2+ 1 target excitation channel, is calculated in the Feshbach formalism. This calculated imaginary potential along with a short ranged volume Woods-Saxon potential to simulate the absorption in fusion channel reproduces the angular distributions for 16O+146Nd quite well. But for 16O+142,144Nd systems additional surface absorption is found to be necessary to fit the angular distribution data. The variations of this additional absorption term with incident energy and the mass of the target are explored. © 2003 Elsevier Science B.V. All rights reserved
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