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Statistics-tuned phases of pseudofermions in one dimension
No full textWe show that a quadratic system of pseudofermions, with tunable fractionalized statistics, can host a rich phase diagram on a one-dimensional chain with nearest- and next-nearest-neighbor hopping. Using a combination of numerical and analytical techniques, we show that by varying the statistical angle and the ratio of the hopping, the system stabilizes two Tomonaga-Luttinger liquids (TLL) with central charges c = 1 and 2, respectively, along with the inversion symmetry broken bond-ordered (BO) insulating phase. Interestingly, the two quantum phase transitions in the system, (1) between the two TLLs and (2) the c = 1 TLL and BO phase, can be engendered by solely tuning the statistics of the pseudofermions. Our analysis shows that both these transitions are continuous and novel with the former lacking a local order-parameter based description and the latter of Berezinskii-Kosterlitz-Thouless type. These phases and phase transitions can be of direct experimental relevance in the context of recent studies of fermionic cold atoms
Strong Coupling of an Emitter with Absorbing Matter: A Regime for Enhancement of Light Emission
No full textThis work shows that, counterintuitively, adding extremely small (< 10 nm in dimension) fully absorbing metal nanoparticles to a material can notably enhance its light emission. It also shows that the mystery behind the unexpected large enhancements in surface-enhanced Raman spectroscopy, even greater than a factor of 10(10), is the tunneling out of photons from the strongly absorbing metal surface. Dynamics in a strongly coupled emitter-matter quantum system demands such behavior in the case of limiting small metal nanoparticles and proximal metal surfaces. This effect can be exploited further in light generation, optical sensing, and radiative heat transfer
A new species of Ahaetulla Link, 1807 (Serpentes: Colubridae: Ahaetullinae) from India
No full textA new species of vine snake of the genus Ahaetulla is described from peninsular India. The new taxon is a medium-sized arboreal snake, readily distinguished from all other congeners by morphological and genetic differences. The new species appears to be widely distributed in Eastern Ghats and Central India with the western-most distribution extending into eastern Rajasthan. However, it is relatively rare, with only three specimens being acquired over the past nine years
EPR and Optical Properties of UV-B Radiation-Emitting Gd3+-Doped BaLa2ZnO5 Host Prepared by Sol-Gel Method
No full textA series of trivalent gadolinium ion-doped BaLa2ZnO5 phosphors was prepared by the sol-gel technique. Phase purity and crystal structure were confirmed by the Rietveld refinement. The morphology of the sample was studied by scanning electron microscopy. The effect of Gd3+ concentration on the luminescence of the BaLa2-xGdxZnO5 (x=0.01x0.15) samples was investigated by photoluminescence spectra. Under excitation at 273nm, all the samples showed ultraviolet emission near 314nm, generated by the (P7/2S7/2)-P-6-S-8 transition of Gd3+ ions. It was found that the emission intensity increased with the concentration of Gd3+ ions up to 0.15mol without concentration quenching. The electron paramagnetic resonance spectra of the Gd3+ ion-doped BaLa2ZnO5 phosphors indicated that the dopant ions occupied slightly distorted La3+ sites in the host lattice. Both the PL and EPR studies describe the excited and ground-state features of Gd3+ ions in the BaLa2ZnO5 host lattice
A simple method for estimating the quality factor of cylindrical re-entrant cavity of Klystrons
No full textA simple method for estimation of the unloaded quality factor of single and double re-entrant cylindrical cavities was developed based on Wheeler�s incremental inductance rule. The proposed approach was benchmarked for a Ka-band re-entrant cavity against 3D electromagnetic simulation using CST Studio and also with measurements. The analysis is general and unlike the approach of Fujisawa, it could be extended to analyze the re-entrant cavity comprising dissimilar materials. The effect of surface roughness on the quality factor of the cavity also could be estimated using the present analysis. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group
Vertical distribution of chlorophyll in dynamically distinct regions of the southern Bay of Bengal
No full textThe Bay of Bengal (BoB) generally exhibits surface oligotrophy due to nutrient limitation induced by strong salinity stratification. Nevertheless, there are hotspots of high chlorophyll in the BoB where the monsoonal forcings are strong enough to break the stratification; one such region is the southern BoB, east of Sri Lanka. A recent field programme conducted during the summer monsoon of 2016, as a part of the Bay of Bengal Boundary Layer Experiment (BoBBLE), provides a unique high-resolution dataset of the vertical distribution of chlorophyll in the southern BoB using ocean gliders along with shipboard conductivity- temperature-depth (CTD) measurements. Observations were carried out for a duration of 12-20 days, covering the dynamically active regions of the Sri Lanka Dome (SLD) and the Southwest Monsoon Current (SMC). Mixing and up-welling induced by the monsoonal wind forcing enhanced surface chlorophyll concentrations (0.3-0.7 mg m(-3)). Prominent deep chlorophyll maxima (DCM; 0.3-1.2 mg mg(-3)) existed at intermediate depths (20-50 m), signifying the contribution of subsurface productivity to the biological carbon cycling in the BoB. The shape of chlorophyll profiles varied in different dynamical regimes; up-welling was associated with sharp and intense DCM, whereas mixing resulted in a diffuse and weaker DCM. Within the SLD, open-ocean Ekman suction favoured a substantial increase in chlorophyll. Farther east, where the thermocline was deeper, enhanced surface chlorophyll was associated with intermittent mixing events. Remote forcing by the westward propagating Rossby waves influenced the upper-ocean dynamics and chlorophyll distribution in the southern BoB. Stabilizing surface freshening events and barrier-layer formation often inhibited the generation of surface chlorophyll. The pathway of the SMC intrusion was marked by a distinct band of chlorophyll, indicating the advective effect of biologically rich Arabian Sea waters. The region of the monsoon current exhibited the strongest DCM as well as the highest column-integrated chlorophyll. Observations suggest that the persistence of DCM in the southern BoB is promoted by surface oligotrophy and shallow mixed layers. Results from a coupled physical-ecosystem model substantiate the dominant role of mixed layer processes associated with the monsoon in controlling the nutrient distribution and biological productivity in the southern BoB. The present study provides new insights into the vertical distribution of chlorophyll in the BoB, emphasizing the need for extensive in situ sampling and ecosystem model-based efforts for a better understanding of the biophysical interactions and the potential climatic feedbacks
Layer degree of freedom for excitons in transition metal dichalcogenides
No full textLayered transition metal dichalcogenides (TMDCs) host a variety of strongly bound exciton complexes that control the optical properties in these materials. Apart from spin and valley, layer index provides an additional degree of freedom in a few-layer-thick film. Here we show that in a few-layer TMDC film, the wave functions of the conduction and valence-band-edge states contributing to the K (K') valley are spatially confined in the alternate layers-giving rise to direct (quasi-)intralayer bright exciton and lower-energy interlayer dark excitons. Depending on the spin and valley configuration, the bright-exciton state is further found to be a coherent superposition of two layer-induced states, one (E type) distributed in the even layers and the other (O type) in the odd layers. The intralayer nature of the bright exciton manifests as a relatively weak dependence of the exciton binding energy on the thickness of the few-layer film, and the binding energy is maintained up to 50 meV in the bulk limit-which is an order of magnitude higher than conventional semiconductors. Fast Stokes energy transfer from the intralayer bright state to the interlayer dark states provides a clear signature in the layer-dependent broadening of the photoluminescence peak, and plays a key role in the suppression of the photoluminescence intensity observed in TMDCs with thickness beyond a monolayer
Stress activated p38 MAPK regulates cell cycle via AP-1 factors in areca extract exposed human lung epithelial cells
No full textAreca nut chewing habits are associated with several oral manifestations like leukoplakia, submucous fibrosis and oral squamous cell carcinoma. Although numerous evidence on areca toxicity is known but the mechanistic pathway of disease causation is to be studied. Aqueous areca nut extract treated A549 cells showed reduced cell viability by 48 h with IC50 value of 0.50%. The toxic nature of areca nut induced the production of reactive oxygen species with decreased anti-oxidant glutathione S transferase levels lead to altered redox homeostasis. PCR studies showed decreased mRNA levels of Jun and Fos AP-1 subunits on extract treatment by 48 h. The protein levels of PCNA, CDK4, RB, p53, c-Jun and c-Fos were found to be downregulated with upregulated CDK inhibitor p21 on extract treatment as compared to control. Results of FACS analysis further confirm G(1)/S phase cell cycle arrest on areca nut extract exposure. The regulation of downstream AP-1 subunits by MAPKs was studied by using specific inhibitors of ERK, JNK and p38 along with areca nut extract. Results showed the redox activation of MAP kinases down regulated the mRNA levels of AP-1 subunits in aqueous areca nut extract treated cells. Hence the present study aids in elucidating the role of MAP kinases in regulating the AP-1 subunits and their implications on target genes that are involved regulation of various cellular processes. Further, it would help in understanding the mechanistic aspects of the diseased state which may facilitate in designing of new therapeutic modalities that could help in cancer management
Current status of MSSM Higgs sector with LHC 13 TeV data
No full textATLAS and CMS Collaborations have reported the results on the Higgs search analyzing approximate to 36 fb(-1) data from Run-II of LHC at 13 TeV. In this work, we study the Higgs sector of the phenomenological Minimal Supersymmetric Standard Model, in light of the recent Higgs data, by studying separately the impact of Run-I and Run-II data. One of the major impacts of the new data on the parameter space comes from the direct searches of neutral CP-even and CP-odd heavy Higgses (H and A, respectively) in the H/A+- channel which disfavours high tan regions more efficiently than Run-I data. Secondly, we show that the latest result of the rare radiative decay of B meson imposes a slightly stronger constraint on low tan and low M-A region of the parameter space, as compared to its previous measurement. Further, we find that in a global fit Run-II light Higgs signal strength data is almost comparable in strength with the corresponding Run-I data. Finally, we discuss scenarios with the heavy Higgs boson decaying into electroweakinos and third generation squarks and sleptons
