9,239 research outputs found

    Research Notes : India : Heritability estimates for seed quality traits in soybean

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    Breeding programs with primary emphasis on yield and resistance to dis-eases are in progress at this center since 1967-68. Rapid strides have since been made in this direction with breeding and release of several high-yield-ing soybean varieties, viz: Ankur, Alankar, Shilajeet, PK-262, PK-327, PK-308, and PK-416. However, still a constraint to expansion of soybean cultivation in tropics seems to be deterioration of seed quality in storage

    Critical Cooperation Range to Improve Spatial Network Robustness

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    A robust worldwide air-transportation network (WAN) is one that minimizes the number of stranded passengers under a sequence of airport closures. Building on top of this realistic example, here we address how spatial network robustness can profit from cooperation between local actors. We swap a series of links within a certain distance, a cooperation range, while following typical constraints of spatially embedded networks. We find that the network robustness is only improved above a critical cooperation range. Such improvement can be described in the framework of a continuum transition, where the critical exponents depend on the spatial correlation of connected nodes. For the WAN we show that, except for Australia, all continental networks fall into the same universality class. Practical implications of this result are also discussed

    Computation of Kolmogorov's Constant in Magnetohydrodynamic Turbulence

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    In this paper we calculate Kolmogorov's constant for magnetohydrodynamic turbulence to one loop order in perturbation theory using the direct interaction approximation technique of Kraichnan. We have computed the constants for various Eu(k)/Eb(k)E^u(k)/E^b(k), i.e., fluid to magnetic energy ratios when the normalized cross helicity is zero. We find that KK increases from 1.47 to 4.12 as we go from fully fluid case (Eb=0)(E^b=0) to a situation when Eu/Eb=0.5% E^u/E^b=0.5, then it decreases to 3.55 in a fully magnetic limit (Eu=0)(E^u=0). When Eu/Eb=1E^u/E^b=1, we find that K=3.43K=3.43.Comment: Latex, 10 pages, no figures, To appear in Euro. Phys. Lett., 199

    Energy fluxes in helical magnetohydrodynamics and dynamo action

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    Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is to first-order in perturbation. Kinetic and magnetic helicities do not affect the renormalized parameters, but they induce an inverse cascade of magnetic energy. The sources for the the large-scale magnetic field have been shown to be (1) energy flux from large-scale velocity field to large-scale magnetic field arising due to nonhelical interactions, and (2) inverse energy flux of magnetic energy caused by helical interactions. Based on our flux results, a premitive model for galactic dynamo has been constructed. Our calculations yields dynamo time-scale for a typical galaxy to be of the order of 10810^8 years. Our field-theoretic calculations also reveal that the flux of magnetic helicity is backward, consistent with the earlier observations based on absolute equilibrium theory.Comment: REVTEX4; A factor of 2 corrected in helicit

    Local shell-to-shell energy transfer via nonlocal Interactions in fluid turbulence

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    In this paper we analytically compute the strength of nonlinear interactions in a triad, and the energy exchanges between wavenumber shells in incompressible fluid turbulence. The computation has been done using first-order perturbative field theory. In three dimension, magnitude of triad interactions is large for nonlocal triads, and small for local triads. However, the shell-to-shell energy transfer rate is found to be local and forward. This result is due to the fact that the nonlocal triads occupy much less Fourier space volume than the local ones. The analytical results on three-dimensional shell-to-shell energy transfer match with their numerical counterparts. In two-dimensional turbulence, the energy transfer rates to the near-by shells are forward, but to the distant shells are backward; the cumulative effect is an inverse cascade of energy.Comment: 10 pages, Revtex

    Validation of Constructs for Buyer Supplier Relationship Development Strategies: Indian Manufacturing Context

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    Focus of buyer is to satisfy the end user with improved quality and diversified range. As it is not possible to manufacture all components in house, supplier base of buyer should be self-efficient and developed one. This development of supplier can be achieved by applying different supplier development practices as per the requirement, For being competitive in market, supplier base of buyer should be self-efficient and this can be achieved through implementing supplier development practices Excellence in supplier development and relationship improvement results in betterment of supply chain performance. In this article, a new measurement scale to assess the supplier development practices, relationship between the buyer and the supplier with competitive advantages and profitability is developed and validated. To examine the impact of supplier development practices in the context of buyer–supplier performance, a survey was conducted on 512 manufacturing companies. The multi-item scale shows strong evidence of reliability as well as convergent, discriminant validity in a sample. Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA) and Reliability Analysis is applied on data for validation of instrument. Exploratory factor analysis yielded nineteen factors, which were further confirmed by confirmatory factor analysis. Suggestions for applying the measure in future research are presented. Keywords: Supplier Development, Buyer Supplier Relationship Developmen

    Large-Eddy Simulations of Fluid and Magnetohydrodynamic Turbulence Using Renormalized Parameters

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    In this paper a procedure for large-eddy simulation (LES) has been devised for fluid and magnetohydrodynamic turbulence in Fourier space using the renormalized parameters. The parameters calculated using field theory have been taken from recent papers by Verma [Phys. Rev. E, 2001; Phys. Plasmas, 2001]. We have carried out LES on 64364^3 grid. These results match quite well with direct numerical simulations of 1283128^3. We show that proper choice of parameter is necessary in LES.Comment: 12 pages, 4 figures: Proper figures inserte

    High-efficiency WSi superconducting nanowire single-photon detectors for quantum state engineering in the near infrared

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    We report on high-efficiency superconducting nanowire single-photon detectors based on amorphous WSi and optimized at 1064 nm. At an operating temperature of 1.8 K, we demonstrated a 93% system detection efficiency at this wavelength with a dark noise of a few counts per second. Combined with cavity-enhanced spontaneous parametric down-conversion, this fiber-coupled detector enabled us to generate narrowband single photons with a heralding efficiency greater than 90% and a high spectral brightness of 0.6×1040.6\times10^4 photons/(s\cdotmW\cdotMHz). Beyond single-photon generation at large rate, such high-efficiency detectors open the path to efficient multiple-photon heralding and complex quantum state engineering
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