389 research outputs found

    Pollinator Diversity and Foraging Dynamics on Monsoon Crop of Cucurbits in a Traditional Landscape of South Indian West Coast

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    Studies on insect pollinator ecology and dynamics are very rarely carried out in traditional Indian agriculture landscapes. Indiscriminate landscape changes in the rural areas and tendencies towards crop monocultures can have significant effects on pollinator habitats and effectiveness. This study was aimed at observing insect pollinators, their visitation frequencies and timings on monsoon cucurbit crops such as Cucumis sativus L., C. pubescens Willd., Momordica charantia L., Trichonsanthes anguina L. and Luffa acutangula L. (Roxb.), in a coastal Karnataka Village. This study was also aimed at covering the significance of the surrounding landscape elements in sustaining pollinator elements. Bees, such as Apis dorsata, A. cerana and Trigona sp., were major visitors on all cucurbits, except snake gourd which was pollinated mainly by lepidopterans. Insect species were found to partition floral resources of any given crops between them by minimal overlapping in their visitation timings. Natural elements of the landscape around, mainly a village forest and rocky savanna furnished habitats for bees and lepidopterans. Prolifically blooming monsoon herbs on lateritic plateaus, by providing nectar resources for pollinators, presumably play key role in making the case study village well known for monsoon vegetables

    Biosorption of chromium (VI) from aqueous solutions by the husk of Bengal gram ( Cicer arientinum )

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    The potential to remove Cr (VI) from aqueous solutions through biosorption using the husk of Bengal gram ( Cicer arientinum ), was investigated in batch experiments. The results showed removal of 99.9% of chromium in the 10 mgl-1 chromium solution, the biomass required at saturation was 1 g mg-1. Kinetic experiments revealed that the dilute chromium solutions reached equilibrium within 180 min. The biosorptive capacity of the (bgh) was dependent on the pH of the chromium solution, with pH 2 being optimal. The adsorption data fit well with the Langmuir and Freundlich isotherm models. The adsorption capacity calculated from the Langmuir isotherm was 91.64 mg Cr (VI)/g at pH 2. The adsorption capacity increased with increase in agitation speed and an optimum was achieved at 120 rpm. The biosorption of Cr (VI) was studied by Fourier transform infrared spectroscopy (FTIR), which suggested that the presence of Cr (VI) ions in the biomass affects the bands corresponding to hydroxyl and carboxyl groups. Comprehensive characterisation of parameters indicates bgh to be an excellent material for biosorption of Cr (VI) to treat wastewaters containing low concentration of the metal

    Synthesis of 5 : 6-dihydroxyflavonols - Part I

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    Methyl ethers of 5 : 6-dihydroxy-chalkones and flavanones have been prepared. 2 : 5-Dihydroxy-6-methoxy acetophenone has been condensed with vanillin and 5 : 6-dimethoxy-2-hydroxy-acetophenone with veratric aldehyde and anisaldehyde; the resulting chalkones have been converted into the flavanones. In the above reactions mixtures of chalkones and flavanones result

    Constitution of oroxylin-A and synthesis of its diethyl-ether

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    The experiments described in this paper show that a pure sample of oroxylin-A melts at 219–20° (acetate, 139–40°), that the substance melting at 231–32° is a mixture of it with chrysin and that this mixture could be separated by fractionation of the acetates. The constitution of oroxylin-A as the 6-methyl ether of baicalein is confirmed by ethylating it to the diethyl ether and showing that the product is identical with a synthetic sample of 6-methoxy-5 : 7-diethoxy flavone. The details of the synthesis are given

    Study of Magnetic Properties of A_2B^'NbO_6 (A=Ba,Sr, (BaSr): and B^'=Fe and Mn) double perovskites

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    We have studied the magnetic properties of Ba_2FeNbO_6 and Ba_2MnNbO_6. it is seen that Ba_2FeNbO_6 is an antiferromagnet with a weak ferromagnetic behaviour at 5K while Ba_2MnNbO_6 shows two magnetic transitions one at 45 K and the other at 12K. Electron spin resonance (ESR) measurements at room temperature show that the Mn compound does not show any Jahn-Teller distortion. It is also seen that the Neel temperature of the A_2FeNbO_6 (A=Ba,Sr, BaSr) compounds do not vary significantly. However variations in the average A-site ionic radius influence the formation of short range correlations that persist above T_N.Comment: 10 oages, 5 figures, MMM, to appear in J.Appl.Phy

    Effects of ramped wall temperature and concentration on viscoelastic Jeffrey’s fluid flows from a vertical permeable cone

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    In thermo-fluid dynamics, free convection flows external to different geometries such as cylinders, ellipses, spheres, curved walls, wavy plates, cones etc. play major role in various industrial and process engineering systems. The thermal buoyancy force associated with natural convection flows can exert a critical role in determining skin friction and heat transfer rates at the boundary. In thermal engineering, natural convection flows from cones has gained exceptional interest. A theoretical analysis is developed to investigate the nonlinear, steady-state, laminar, non-isothermal convection boundary layer flows of viscoelastic fluid from a vertical permeable cone with a power-law variation in both temperature and concentration. The Jeffery’s viscoelastic model simulates the non-Newtonian characteristics of polymers, which constitutes the novelty of the present work. The transformed conservation equations for linear momentum, energy and concentration are solved numerically under physically viable boundary conditions using the finite-differences Keller-Box scheme. The impact of Deborah number (De), ratio of relaxation to retardation time (λ), surface suction/injection parameter (fw), power-law exponent (n), buoyancy ratio parameter (N) and dimensionless tangential coordinate (Ѯ) on velocity, surface temperature, concentration, local skin friction, heat transfer rate and mass transfer rate in the boundary layer regime are presented graphically. It is observed that increasing values of De reduces velocity whereas the temperature and concentration are increased slightly. Increasing λ enhance velocity however reduces temperature and concentration slightly. The heat and mass transfer rate are found to decrease with increasing De and increase with increasing values of λ. The skin friction is found to decrease with a rise in De whereas it is elevated with increasing values of λ. Increasing values of fw and n, decelerates the flow and also cools the boundary layer i.e. reduces temperature and also concentration. The study is relevant to chemical engineering systems, solvent and polymeric processes

    Harmonic Sums and Mellin Transforms up to two-loop Order

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    A systematic study is performed on the finite harmonic sums up to level four. These sums form the general basis for the Mellin transforms of all individual functions fi(x)f_i(x) of the momentum fraction xx emerging in the quantities of massless QED and QCD up to two--loop order, as the unpolarized and polarized splitting functions, coefficient functions, and hard scattering cross sections for space and time-like momentum transfer. The finite harmonic sums are calculated explicitly in the linear representation. Algebraic relations connecting these sums are derived to obtain representations based on a reduced set of basic functions. The Mellin transforms of all the corresponding Nielsen functions are calculated.Comment: 44 pages Latex, contract number adde

    Stain-Free Quantification of Chromosomes in Live Cells Using Regularized Tomographic Phase Microscopy

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    Refractive index imaging is a label-free technique that enables long-term monitoring of the internal structures and molecular composition in living cells with minimal perturbation. Existing tomographic methods for the refractive index imaging lack 3-D resolution and result in artifacts that prevent accurate refractive index quantification. To overcome these limitations without compromising the capability to observe a sample in its most native condition, we have developed a regularized tomographic phase microscope (RTPM) enabling accurate refractive index imaging of organelles inside intact cells. With the enhanced accuracy, we quantify the mass of chromosomes in intact living cells, and differentiate two human colon cancer lines, HT-29 and T84 cells, solely based on the non-aqueous (dry) mass of chromosomes. In addition, we demonstrate chromosomal imaging using a dual-wavelength RTPM, which shows its potential to determine the molecular composition of cellular organelles in live cells.National Institute of Biomedical Imaging and Bioengineering (U.S.) (9P41EB015871-26A1

    Human Protein Reference Database—2009 update

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    Human Protein Reference Database (HPRD—http://www.hprd.org/), initially described in 2003, is a database of curated proteomic information pertaining to human proteins. We have recently added a number of new features in HPRD. These include PhosphoMotif Finder, which allows users to find the presence of over 320 experimentally verified phosphorylation motifs in proteins of interest. Another new feature is a protein distributed annotation system—Human Proteinpedia (http://www.humanproteinpedia.org/)—through which laboratories can submit their data, which is mapped onto protein entries in HPRD. Over 75 laboratories involved in proteomics research have already participated in this effort by submitting data for over 15 000 human proteins. The submitted data includes mass spectrometry and protein microarray-derived data, among other data types. Finally, HPRD is also linked to a compendium of human signaling pathways developed by our group, NetPath (http://www.netpath.org/), which currently contains annotations for several cancer and immune signaling pathways. Since the last update, more than 5500 new protein sequences have been added, making HPRD a comprehensive resource for studying the human proteome
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