On the third order structure function for rotating 3D homogeneous turbulent flow

A form for the two-point third order structure function has been calculated for three dimensional homogeneous incompressible slowly rotating turbulent fluid. It has been argued that it may possibly hint at the initiation of the phenomenon of two-dimensionalisation of the 3D incompressible turbulence owing to rotation.Comment: This revised version corrects some serious flaws in the discussions after the equation (2) and the equation (13) of the earlier version. Some typos are also correcte

Shell Crossing Singularities in Quasi-Spherical Szekeres Models

We investigate the occurrence of shell crossing singularities in quasi-spherical Szekeres dust models with or without a cosmological constant. We study the conditions for shell crossing singularity both from physical and geometrical point of view and they are in agreement.Comment: 10 latex pages, RevTex style, no figure

Symmetry-dependent phonon renormalization in monolayer MoS2 transistor

Strong electron-phonon interaction which limits electronic mobility of semiconductors can also have significant effects on phonon frequencies. The latter is the key to the use of Raman spectroscopy for nondestructive characterization of doping in graphene-based devices. Using in-situ Raman scattering from single layer MoS$_2$ electrochemically top-gated field effect transistor (FET), we show softening and broadening of A$_{1g}$ phonon with electron doping whereas the other Raman active E$_{2g}^{1}$ mode remains essentially inert. Confirming these results with first-principles density functional theory based calculations, we use group theoretical arguments to explain why A$_{1g}$ mode specifically exhibits a strong sensitivity to electron doping. Our work opens up the use of Raman spectroscopy in probing the level of doping in single layer MoS$_2$-based FETs, which have a high on-off ratio and are of enormous technological significance.Comment: 5 pages, 3 figure

Interchannel coupling effects in the spin polarization of energetic photoelectrons

Effects of the interchannel coupling on the spin polarization of energetic photoelectrons emitted from atomic Ne valence subshells are examined. Like previously obtained results for cross sections and angular distributions, the photoelectron spin polarization parameters too are found considerably influenced by the coupling. The result completes a series of studies to finally conclude that the independent particle description is inadequate for the {\em entire} range of photoionization dynamics over the {\em full} spectral energy domainComment: 7 pages, 5 figures, accepted in Phys. Rev.

Electron-Hole Asymmetry in the Electron-phonon Coupling in Top-gated Phosphorene Transistor

Using in-situ Raman scattering from phosphorene channel in an electrochemically top-gated field effect transistor, we show that its phonons with A$_g$ symmetry depend much more strongly on concentration of electrons than that of holes, while the phonons with B$_g$ symmetry are insensitive to doping. With first-principles theoretical analysis, we show that the observed electon-hole asymmetry arises from the radically different constitution of its conduction and valence bands involving $\pi$ and $\sigma$ bonding states respectively, whose symmetry permits coupling with only the phonons that preserve the lattice symmetry. Thus, Raman spectroscopy is a non-invasive tool for measuring electron concentration in phosphorene-based nanoelectronic devices

Phylogenetic Relationships of Trichoderma isolates of North Bengal Based on Sequence Analysis of ITS Region of rDNA

Abstract: The aim of this study was to determine whether sequence analysis of internal transcribed spacer-1 (ITS1) region of the ribosomal DNA can be used to detect phylogenetic relationships of Trichoderma isolates obtained from North Bengal region. ITS 1 of the rDNA of thirteen Trichoderma isolates was amplified by polymerase chain reaction (PCR) using universal primers (ITS1 and ITS4). PCR products were purified and these purified products were used to amplify the ITS 4 region of all Trichoderma isolates. The amplified DNA was sequenced and aligned against ex-type strain sequences from TrichoBLAST and established Trichoderma taxonomy. Nine isolates were positively identified as Trichoderma harzianum and four as Trichoderma erinaceum which were used as an outgroup in these analyses. The ITS-1 region sequences have been used as the reference's sequence and may be used for future study involving the identification and taxonomy of Trichoderma harzianum. Amplification of ITS1 region of the rDNA has showed potential as a rapid technique for identifying Trichoderma harzianum successfully in all cases

In silico study of RxLR effectors of Phytophthora infestans HP-10-31, A2 mating type potato late blight pathogen

Phytophthora infestans is one of the most compelling plant pathogen among the scientific community throughout the world. It is the causative agent of potato late blight and responsible for tremendous economic loss worldwide. Pathogenic effector proteins are instrumental in modulating host immunity and disease resistance has been a major concern. In P. infestans, a class of cytoplasmic effectors recognized as RxLR is characterized by highly conserved region and abet in parasitic colonization by modifying the host defense system. We have sequenced an Indian strain of P. infestans HP-10-31 genome and identified several RxLR motif-containing genes.In this study we selected two RxLR effector genes named contig15921_2 and contig06738_6 from this A2 mating type strain. We used I-TASSER server to generate three-dimensional structure and observe the Nicotinamide adenine dinucleotide and S-adenosyl-Lhomocysteine conserve domains. Our in silico study reveals the binding properties of these proteins are favorable with corresponding ligands. This study gives insight into the interaction between putative RxLR effector proteins with its ligand that further aid our understanding of host-pathogen interaction and help in designing new agents to combat the agro pathogenicity

Signatures of two-dimensionalisation of 3D turbulence in presence of rotation

A reason has been given for the inverse energy cascade in the two-dimensionalised rapidly rotating 3D incompressible turbulence. For such system, literature shows a possibility of the exponent of wavenumber in the energy spectrum's relation to lie between -2 and -3. We argue the existence of a more strict range of -2 to -7/3 for the exponent in the case of rapidly rotating turbulence which is in accordance with the recent experiments. Also, a rigorous derivation for the two point third order structure function has been provided helping one to argue that even with slow rotation one gets, though dominated, a spectrum with the exponent -2.87, thereby hinting at the initiation of the two-dimensionalisation effect with rotation.Comment: An extended and typos-corrected version of the earlier submissio