10,994 research outputs found

    Designing of siRNAs for various target genes of Cucumber mosaic virus subgroup IB

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    119-125Cucumber mosaic virus (CMV) is a major production constraint in black pepper causing stunted disease. Resistant varieties are unavailable and control measures are not effective till now. Recently, RNA interference (RNAi) is the most promising strategy for combating virus infection in plants but the effectiveness depends on sequence specificity between the transgene and the targeting virus. This study was undertaken to design the most suitable region for double stranded RNA synthesis with maximum specificity and minimized off–targets for all the five genes of CMV from black pepper. A 400 bp off–target minimized region identified from each of the five genes was subjected to sequence polymorphism study with selected CMV subgroup IB strains and common ‘siRNAs’ were designed in silico. As 3b gene had the least variations (of 17%) with four common and potential siRNAs designed from this region in silico, a hairpin construct was assembled using this region in Agrobacterium that can be used for developing black pepper resistant to selected CMV subgroup IB strains

    A CLEAN-based Method for Deconvolving Interstellar Pulse Broadening from Radio Pulses

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    Multipath propagation in the interstellar medium distorts radio pulses, an effect predominant for distant pulsars observed at low frequencies. Typically, broadened pulses are analyzed to determine the amount of propagation-induced pulse broadening, but with little interest in determining the undistorted pulse shapes. In this paper we develop and apply a method that recovers both the intrinsic pulse shape and the pulse broadening function that describes the scattering of an impulse. The method resembles the CLEAN algorithm used in synthesis imaging applications, although we search for the best pulse broadening function, and perform a true deconvolution to recover intrinsic pulse structre. As figures of merit to optimize the deconvolution, we use the positivity and symmetry of the deconvolved result along with the mean square residual and the number of points below a given threshold. Our method makes no prior assumptions about the intrinsic pulse shape and can be used for a range of scattering functions for the interstellar medium. It can therefore be applied to a wider variety of measured pulse shapes and degrees of scattering than the previous approaches. We apply the technique to both simulated data and data from Arecibo observations.Comment: 9 pages, 6 figures, Accepted for publication in the Astrophysical Journa

    On Observing Dynamic Prioritised Actions in SOC

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    We study the impact on observational semantics for SOC of priority mechanisms which combine dynamic priority with local pre-emption. We define manageable notions of strong and weak labelled bisimilarities for COWS, a process calculus for SOC, and provide alternative characterisations in terms of open barbed bisimilarities. These semantics show that COWS’s priority mechanisms partially recover the capability to observe receive actions (that could not be observed in a purely asynchronous setting) and that high priority primitives for termination impose specific conditions on the bisimilarities

    Surface recombination measurements on III–V candidate materials for nanostructure light-emitting diodes

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    Surface recombination is an important characteristic of an optoelectronic material. Although surface recombination is a limiting factor for very small devices it has not been studied intensively. We have investigated surface recombination velocity on the exposed surfaces of the AlGaN, InGaAs, and InGaAlP material systems by using absolute photoluminescence quantum efficiency measurements. Two of these three material systems have low enough surface recombination velocity to be usable in nanoscale photonic crystal light-emitting diodes

    Hydropriming -a useful technique for seed invigoration in okra (Abelmoschus esculentus) and parsley (Petroselinum crispum)

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    Seed germinating ability and stand establishment determine the management options in crop production system. Physiological advancement of seeds through priming is a simple and cost-effective method to improve the germinability and stand of any crop. Studies were performed on seed invigoration through hydropriming at the division of PHT, SKUAST-Kashmir during the year 2016 to optimize the hydropriming duration for improved germi-nation and seedling vigour of okra (Pusa sawani) and parsley (curly type). Freshly harvested seeds were soaked in normal water for varying durations (okra- 12, 18 and 24 h; parsley- 24, 48 and 72 h) at (25±2°C) and re-dried to original moisture content at room temperature. Fifty seeds of each treatment were cultured in 14.0 cm Petri dishes lined with 5 layers of moist blotting paper. Observations on various germination parameters were recorded at (25±2°C). Priming of okra seeds for 18 h resulted in highest FGP (85.7%), GE (66.5%), GI (36.7), SDB (29.1mg) and SVI (2.49) coupled with minimum values of T50 (2.75 day) as well as MGT (2.38 day). However, the highest FGP (78.7%), GE (48.7%), SDB (3.13 mg), GI (12.8) and SVI (0.25) together with minimum T50 (7.2 day) and MGT (6.5 day) in parsley was recorded with 24 h priming duration. As such priming duration of 18 and 24 hours at 25±2°C were found optimal for enhanced and rapid seed germination with vigourous seedlings

    Anomalous spin dynamics in charge ordered, 'two-electron' doped manganite Ca_0.9Ce_0.1MnO_3 : consequence of a spin-liquid phase?

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    The 'two-electron' doped rare earth mangnites Ca_1-x Ce_x MnO_3 (x = 0.1,0.2) are probed using resistivity, ac susceptibility and electron paramagnetic resonance (EPR) measurements across their respective charge ordering (CO) temperatures T_CO = 173 K and 250 K. The EPR 'g' factor and intensity as well as the transport and magnetic behaviours of the two compositions are qualitatively similar and are as expected for CO systems. However, the EPR linewidth, reflective of the spin dynamics, for x = 0.1, shows a strongly anomalous temperature dependence, decreasing with decreasing temperature below T_CO in contrast with the sample with x = 0.2 and other CO systems. Keeping in view the evidence for magnetic frustration in the system, we propose that the anomalous temperature dependence of the linewidth is the signature of the occurrence of a disorder driven spin liquid phase, present along with charge ordering.Comment: 19 pages including 4 figure

    Physico-Chemical Characterization Of Sweet Chestnut (Castanea Sativa L.) Starch Grown In Temperate Climate Of Kashmir, India

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    Studies were conducted to characterize the chestnut starch for physico-chemical properties. Chemical composition of chestnut starch showed low levels of protein and ash indicating purity of starch. The results revealed low water and oil absorption capacity of chestnut starch. Starch showed high swelling power and low solubility index. Swelling power and solubility index of chestnut starch increased with increase in temperature (50–90 °C). The results revealed high initial, peak, setback, breakdown, and final viscosity but low paste development temperature. Transmittance (%) of the starch gel was low and decreased with increasing storage period. The chestnut starch gel showed increase in % water release (syneresis) with increase in time of storage but was less susceptible to repeated cycles of freezing and thawing. Starch was also characterized for granule morphology. Starch granules were of round and oval shapes, some granules showed irregular shape

    Primary calcified hydatid of spleen: a case report

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    Most splenic cysts are parasitic. Hydatid disease, a parasitic disease, isendemic in Kashmir. Splenic involvement alone in hydatid disease is very rare. It may remain asymptomatic or, by causing pressure due to increasing size on adjacent viscera, may become symptomatic. A non specific presentation always makes diagnosis difficult. A case of hydatid spleen in a young boy who presented with abdominal pain is reported. Radiology complemented with serology made the diagnosis. Hydatid disease should beconsidered as a differential diagnosis in every patient with a calcified cystic mass of the spleen in endemic areas.KEY WORDS: Calcified hydatid; Spleen; Splenic cyst; Case repor

    High-Spin Doublet Band Structures in odd-odd 194−200^{194-200}Tl isotopes

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    The basis space in the triaxial projected shell model (TPSM) approach is generalized for odd-odd nuclei to include two-neutron and two-proton configurations on the basic one-neutron coupled to one-proton quasiparticle state. The generalization allows to investigate odd-odd nuclei beyond the band crossing region and as a first application of this development, high-spin band structures recently observed in odd-odd 194−200^{194-200}Tl isotopes are investigated. In some of these isotopes, the doublet band structures observed after the band crossing have been conjectured to arise from the spontaneous breaking of the chiral symmetry. The driving configuration of the chiral symmetry in these odd-odd isotopes is one-proton and three-neutrons rather than the basic one-proton and one-neutron as already observed in many other nuclei. It is demonstrated using the TPSM approach that energy differences of the doublet bands in 194^{194}Tl and 198^{198}Tl are, indeed, small. However, the differences in the calculated transition probabilities are somewhat larger than what is expected in the chiral symmetry limit. Experimental data on the transition probabilities is needed to shed light on the chiral nature of the doublet bands.Comment: 11 pages, 17 figures, to appear in EPJ

    Excitonic effects on the two-color coherent control of interband transitions in bulk semiconductors

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    Quantum interference between one- and two-photon absorption pathways allows coherent control of interband transitions in unbiased bulk semiconductors; carrier population, carrier spin polarization, photocurrent injection, and spin current injection may all be controlled. We extend the theory of these processes to include the electron-hole interaction. Our focus is on photon energies that excite carriers above the band edge, but close enough to it so that transition amplitudes based on low order expansions in k\mathbf{k} are applicable; both allowed-allowed and allowed-forbidden two-photon transition amplitudes are included. Analytic solutions are obtained using the effective mass theory of Wannier excitons; degenerate bands are accounted for, but envelope-hole coupling is neglected. We find a Coulomb enhancement of two-color coherent control process, and relate it to the Coulomb enhancements of one- and two-photon absorption. In addition, we find a frequency dependent phase shift in the dependence of photocurrent and spin current on the optical phases. The phase shift decreases monotonically from π/2\pi /2 at the band edge to 0 over an energy range governed by the exciton binding energy. It is the difference between the partial wave phase shifts of the electron-hole envelope function reached by one- and two-photon pathways.Comment: 31 pages, 4 figures, to be published in Phys. Rev.
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