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Fast holographic deconvolution: a new technique for Precision radio interferometry
No full textRestricted Access. An open-access version is available at arXiv.org (one of the alternative locations)We introduce the Fast Holographic Deconvolution method for analyzing interferometric radio data. Our new
method is an extension ofA-projection/software-holography/forwardmodeling analysis techniques and shares their
precision deconvolution and wide-field polarimetry, while being significantly faster than current implementations
that use full direction-dependent antenna gains. Using data from the MWA 32 antenna prototype, we demonstrate
the effectiveness and precision of our newalgorithm. Fast HolographicDeconvolutionmay be particularly important
for upcoming 21 cm cosmology observations of the Epoch of Reionization and Dark Energy where foreground
subtraction is intimately related to the precision of the data reductio
Imprints Collection : A Cyberscholarship of RRI
No full textRestricted Access, Book chapter from Best practices, case studies and management of content, information and knowledge in LIS profession, 2012, Ed by Nagappa V. Bakkannanavar, Published by Ess Ess Publications, New Delhi.Cyberscholarship is relatively a new phenomenon which is in a
way related to digital form of information. Cyberscholarship
has opened new avenues of looking at scholarship quite different
from print format. This novel method has been adopted to develop
a database termed "Imprints Ccllection" having Digital Repository
of Raman Research Institute as base line. This is expected to act
as a support service to enhance the creativity and collaboration
among the scientists of the Institute and also across different
countries. In addition this also brings global visibility to scholarly
literature of the Institute
Evidence for the continuum in 2D causal set quantum gravity
No full textRestricted Access. An open-access version is available at arXiv.org (one of the alternative locations)We present evidence for a continuum phase in a theory of 2D causal set quantum gravity which contains a dimensionless non-locality parameter epsilon ∈ (0, 1]. We also find a phase transition between this continuum phase and a new crystalline phase which is characterized by a set of covariant observables. For a fixed size of the causal set, the transition temperature β−1c decreases monotonically with epsilon. The locus of the transition in the β2 versus epsilon plane asymptotically approaches to the infinite temperature axis, suggesting that the continuum phase survives the analytic continuation
Comment on "Classical Langevin dynamics of a charged particle moving on a sphere and diamagnetism: A surprise" by Kumar N. and Kumar K. Vijay
No full textRestricted Acces
Modulated phases of lipid membranes induced by sterol derivatives
No full textRestricted Access.We have studied the effect of two secosteroids, namely cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2), on the structure and phase behavior of dipalmitoyl phosphatidylcholine (DPPC) membranes using X-ray diffraction. Temperature–composition phase diagrams of both the systems have been determined from diffraction data of aligned multilayers at 98% relative humidity. The two phase diagrams are found to be almost identical, with the appearance of four distinct modulated phases as a function of secosteroid concentration below the main-transition of the lipid. Three of these phases are characterized by periodic height modulation of the bilayers, whereas the one that occurs at high secosteroid concentrations has a periodic thickness modulation. As far as we know, this is the first report on the thickness modulated phase of lipid bilayers
Method and system for line by line addressing of RMS responding display matrix with wavelets
No full textRestricted AccessA method for line-by-line addressing of RMS responding display matrix with wavelets, said
method comprises steps of: selecting the wavelets such that energy of them is proportional
to an integer power of two to form a wavelet matrix; obtaining select waveform profile by
summing elements of column in the wavelet matrix; obtaining column waveforms by dot
product of data with column of the wavelet matrix; and applying the select waveform and the
corresponding column waveforms by selecting one row of the display matrix at a time
Spectrum and ionization rate of low-energy Galactic cosmic rays
No full textRestricted Access. An open-access version is available at arXiv.org (one of the alternative locations)We consider the rate of ionization of diffuse and molecular clouds in the interstellar medium by Galactic cosmic rays (GCRs) in order to constrain its low-energy spectrum. We extrapolate the GCR spectrum obtained from PAMELA at high energies (≥200 GeV nucleon-1) and a recently derived GCR proton flux at 1-200 GeV from observations of gamma-rays from molecular clouds, and find that the observed average Galactic ionization rate can be reconciled with this GCR spectrum if there is a low-energy cut-off for protons at 10-100 MeV. We also identify the flattening below a few GeV as being due to (a) decrease of the diffusion coefficient and dominance of convective loss at low energy and (b) the expected break in energy spectrum for a constant spectral index in momentum. We show that the inferred CR proton spectrum of ? for Ekin≤ few GeV is consistent with a power-law spectrum in momentum p-2.45± 0.4, which we identify as the spectrum at source. Diffusion loss at higher energies then introduces a steepening by E-α with α˜ 1/3, making it consistent with high-energy measurements