Quantitative Analysis of Books by Bharat Ratna Professor C. N. R. Rao

The paper presents the results of the analysis of 49 books of Prof. C N R Rao, published during 1960 to 2013. The analysis shows that 18 books were written by him singly or jointly with other scientists. The rest (N=31) are works produced under his solo or joint editorship. Thirty five books were published abroad and 14 in India (11 from Delhi) World Scientific published 8 books, Wiley VCH published 4 books, Academic Press and Indian National Science Academy published 3 each, and the rest were published by 22 other publishers. His first book was published at the age of 27. Most of the books were authored by him during his 50s (16 books) and 70s (12 books). All his books were published in English. However, a number of books have been translated into Russian, Chinese, Hindi and Kannada. The popularity of his books can be gauged from the fact that two of his books have run into fourth edition, one to third edition, and five books to second edition. The largest number of books belong to physical chemistry, particularly to solid state chemistry

Biobibliometric portrait of the astronomer Jan Hendrik Oort

Jan Hendrik Oort is recognized as one of the greatest astronomers of the 20th century. His 225 publications that appeared during 1922-1992 are analyzed. Most of the papers of the scientist (N= 170) are non-collaborative. Oort’s first paper was published in 1922 at the age of 23. The period 1957-1961, when Oort was 58-62 years old, was his most productive period (nearly 5 papers per year). From the period of 7th to 13th quinquennium (age 53-87) he produced nearly 4 to 5 papers per year. In the byline of authors his status ranged from first to third and ninth. Oort’s research team comprised of 67 collaborators. C. A. Muller and G.W. Rougoor were his leading collaborators. Most of his papers were published in journals, mostly emanating from Netherlands (N=71), USA (N=55) and UK (27) etc. The publication concentration is 2.27 and publication density 16.16. The most frequent keywords are Galaxy(ies) (N=23), Galactic System (N=17) and Structure (N=17). Finally, it is seen that the data set does not follow Bradford law.

Bulk phantom fields, increasing warp factors and fermion localisation

A bulk phantom scalar field (with negative kinetic energy) in a sine--Gordon type potential is used to generate an exact thick brane solution with an increasing warp factor. It is shown that the growing nature of the warp factor allows the localisation of massive as well as massless spin-half fermions on the brane even without any additional non--gravitational interactions. The exact solutions for the localised massive fermionic modes are presented and discussed. The inclusion of a fermion--scalar Yukawa coupling appears to change the mass spectrum and wave functions of the localised fermion though it does not play the crucial role it did in the case of a decreasing warp factor.Comment: 11 pages, 3 figures, RevTex

Geometry of deformations of branes in warped backgrounds

The `braneworld' (described by the usual worldvolume action) is a D dimensional timelike surface embedded in a N dimensional ($N>D$) warped, nonfactorisable spacetime. We first address the conditions on the warp factor required to have an extremal flat brane in a five dimensional background. Subsequently, we deal with normal deformations of such extremal branes. The ensuing Jacobi equations are analysed to obtain the stability condition. It turns out that to have a stable brane, the warp factor should have a minimum at the location of the brane in the given background spacetime. To illustrate our results we explicitly check the extremality and stability criteria for a few known co-dimension one braneworld models. Generalisations of the above formalism for the cases of (i) curved branes (ii) asymmetrical warping and (iii) higher co-dimension braneworlds are then presented alongwith some typical examples for each. Finally, we summarize our results and provide perspectives for future work along these lines.Comment: 21 pages. Version matching final version. Accepted for publication in Class. Quant. Gra

Fermion localization on degenerate and critical branes

In this work we analyze the localization of fermions on degenerate and critical Bloch branes. This is done directly on physical coordinates, in constrast to some works that has been using conformal coordinates. We find the range of coupling constants of the interaction of fermions with the scalar fields that allow us to have normalizable fermion zero-mode localized on the brane on both, critical and degenerate Bloch branes. In the case of critical branes our results agree with those found in [Class. Quantum Grav. \textbf{27} (2010) 185001]. The results on fermion localization on degenerate Bloch branes are new. We also propose a coupling of fermions to the scalar fields which leads to localization of massless fermion on both sides of a double-brane.Comment: 16 pages, 6 figure

Fermion localization on branes with generalized dynamics

In this letter we consider a specific model of braneworld with nonstandard dynamics diffused in the literature, specifically we focus our attention on the matter energy density, the energy of system, the Ricci scalar and the thin brane limit. As the model is classically stable and capable of localize gravity, as a natural extension we address the issue of fermion localization of fermions on a thick brane constructed out from one scalar field with nonstandard kinetic terms coupled with gravity. The contribution of the nonstandard kinetic terms in the problem of fermion localization is analyzed. It is found that the simplest Yukawa coupling $\eta\bar{\Psi}\phi\Psi$ support the localization of fermions on the thick brane. It is shown that the zero mode for left-handed can be localized on the thick brane depending on the values for the coupling constant $\eta$.Comment: 6 pages, 3 figure

Braneworlds in six dimensions: new models with bulk scalars

Six dimensional bulk spacetimes with 3-- and 4--branes are constructed using certain non--conventional bulk scalars as sources. In particular, we investigate the consequences of having the phantom (negative kinetic energy) and the Brans--Dicke scalar in the bulk while obtaining such solutions. We find geometries with 4--branes with a compact on--brane dimension (hybrid compactification) which may be assumed to be small in order to realize a 3--brane world. On the other hand, we also construct, with similar sources, bulk spacetimes where a 3--brane is located at a conical singularity. Furthermore, we investigate the issue of localization of matter fields (scalar, fermion, graviton, vector) on these 3-- and 4--branes and conclude with comments on our six dimensional models.Comment: 24 pages, 1 figure, Replaced to match version published in Class. Quant. Gra

Telomerase inhibition by siRNA causes senescence and apoptosis in Barrett's adenocarcinoma cells: mechanism and therapeutic potential

BACKGROUND: In cancer cells, telomerase induction helps maintain telomere length and thereby bypasses senescence and provides enhanced replicative potential. Chemical inhibitors of telomerase have been shown to reactivate telomere shortening and cause replicative senescence and apoptotic cell death of tumor cells while having little or no effect on normal diploid cells. RESULTS: We designed siRNAs against two different regions of telomerase gene and evaluated their effect on telomere length, proliferative potential, and gene expression in Barrett's adenocarcinoma SEG-1 cells. The mixture of siRNAs in nanomolar concentrations caused a loss of telomerase activity that appeared as early as day 1 and was essentially complete at day 3. Inhibition of telomerase activity was associated with marked reduction in median telomere length and complete loss of detectable telomeres in more than 50% of the treated cells. Telomere loss caused senescence in 40% and apoptosis in 86% of the treated cells. These responses appeared to be associated with activation of DNA sensor HR23B and subsequent activation of p53 homolog p73 and p63 and E2F1. Changes in these gene regulators were probably the source of observed up-regulation of cell cycle inhibitors, p16 and GADD45. Elevated transcript levels of FasL, Fas and caspase 8 that activate death receptors and CARD 9 that interacts with Bcl10 and NFKB to enhance mitochondrial translocation and activation of caspase 9 were also observed. CONCLUSION: These studies show that telomerase siRNAs can cause effective suppression of telomerase and telomere shortening leading to both cell cycle arrest and apoptosis via mechanisms that include up-regulation of several genes involved in cell cycle arrest and apoptosis. Telomerase siRNAs may therefore be strong candidates for highly selective therapy for chemoprevention and treatment of Barrett's adenocarcinoma