Environmental Issues in Indian Freshwater Aquaculture

Aquaculture is assuming increasing importance in recent years on a global basis including the Indian subcontinent. With possibilities of obtaining high productivity levels among different farming system, there has been a flux between the farming practices and aquaculture is receiving greater investments both in public and private secto

Effect of high-K dielectrics on charge transport in graphene

The effect of various dielectrics on charge mobility in single layer graphene is investigated. By calculating the remote optical phonon scattering arising from the polar substrates, and combining it with their effect on Coulombic impurity scattering, a comprehensive picture of the effect of dielectrics on charge transport in graphene emerges. It is found that though high-$\kappa$ dielectrics can strongly reduce Coulombic scattering by dielectric screening, scattering from surface phonon modes arising from them wash out this advantage. By comparing the room-temperature transport properties with narrow-bandgap III-V semiconductors, strategies to improve the mobility in single layer graphene are outlined.Comment: 6 pages, 4 Figure

SU(2) Chiral Sigma Model Study of Phase Transition in Hybrid Stars

We use a modified SU(2) chiral sigma model to study nuclear matter component and simple bag model for quark matter constituting a neutron star. We also study the phase transition of nuclear matter to quark matter with the mixed phase characterized by two conserved charges in the interior of highly dense neutron stars. Stable solutions of Tolman-Oppenheimer-Volkoff equations representing hybrid stars are obtained with a maximum mass of 1.67$M_{\odot}$ and radius around 8.9 km.Comment: 14 pages, 5 figure

Atomic and electronic structures of neutral and charged boron and boron-rich clusters

Ab initio molecular orbital theory based on both density functional formalism and quantum chemical methods has been used to calculate the equilibrium geometries, binding energies, ionization potentials, fragmentation patterns, and electronic structures of neutral and charged boron clusters containing up to six atoms. Calculations have also been performed on restricted geometries for BnX (n=1,5,12; X=Be, B, C) and B20 clusters to see if clusters can be designed so as to increase their stability. Energetics of doubly chargedB++n clusters have also been studied to find the critical size for Coulomb explosion. The results are compared with existing experimental and theoretical data

Assessment of manual load carrying and health status of women farm workers of district Sonipat (Haryana), India

In present study an assessment of manual load carrying and health status of women farm workers of Thana Kalan village, Kharkhoda tehsil in Sonipat district of Haryana was conducted. A total of forty women farm workers between 25-40 years age were selected with at least five year load carrying experience, involved in farm work, with no history of chronic disease and willingness to participate in the study. The women farm workers carried water, fodder, cow dung on daily basis and seed, fertilizer and other farm inputs and farm produce on seasonal basis. It was observed that preferable mode of load carrying was head. The quantum of load varied between 20-40 kg. Assessment of health status revealed that musculoskeletal disorder was prevalent in all the age groups. Musculoskeletal disorder namely lower back pain was observed in 87.5 per cent women workers, neck pain in 72.5 per cent women workers followed by knee (32.5%) and foot pain (25 %). The pain severity was mild in most of the women farm workers and nobody was bed ridden for back pain due to load carrying. The younger age women (25-30 years) preferred traditional way of oil massage and rest for relief from back pain and neck pain after load carrying, while older women (31-40 years) had to take rest for back pain relief. The issue of occupational health disorder associated with manual load carrying by women farm worker has to receive attention to reduce the potential health risk

The cosmological model in f(R,Tϕ) f(R,T^\phi) gravity with Scalar Field conformity

The homogeneous and isotropic cosmological model in generalized $f(R,T^\phi)$ theories associated with scalar field is discussed, which is motivated by the $f(R,T)$ theory of gravity studied by Harko et al. \cite{Harko:2011kv, Harko:2014pqa}. The $f(R,T^\phi)$ gravity can be explained as $f(R,T)$ gravity with a self-interacting scalar field $\phi$, where $T^\phi$ is the trace of the energy-momentum tensor. The parametrization of Hubble parameter $H(t)$ is taken as $\alpha-\beta e^{-\gamma t}$, where $\alpha$, $\beta$ and $\gamma$ are arbitrary constants such that $\alpha, \gamma>0$ and $\beta<0$. The model shows no space-time singularity and the expansion of the universe will continue forever, i.e., the future scenario of the universe attains Big Freeze. The model predicts the moderate inflationary scenario at the time of the evolution of the universe and it is consistent with $\Lambda$CDM in late times. The consistency of the model has also been examined using recent observational Hubble dataset and supernovae dataset. Finally, the physical features of the model have been discussed in some detail.Comment: 12 pages, 13 figure

Bouncing cosmology in modified gravity with higher-order curvature terms

A bouncing scenario of a flat homogeneous and isotropic universe is explored by using the reconstruction technique for the power-law parametrization of the Hubble parameter in a modified gravity theory with higher-order curvature and trace of the energy-momentum tensor terms. It is demonstrated that bouncing criteria are satisfied so that the cosmological initial singularity can be avoided. In addition, it is shown that the equation of state parameter crosses the line of the phantom divide. In the present scenario, the universe is filled with perfect fluid around the bouncing point, in which the universe becomes highly unstable and a big bounce can be realized. Furthermore, it is found that extremal acceleration occurs at the bouncing point.Comment: 14 pages, 13 figure

Giant Magnetic Moments of Nitrogen Stabilized Mn Clusters and Their Relevance to Ferromagnetism in Mn Doped GaN

Using first principles calculations based on density functional theory, we show that the stability and magnetic properties of small Mn clusters can be fundamentally altered by the presence of nitrogen. Not only are their binding energies substantially enhanced, but also the coupling between the magnetic moments at Mn sites remains ferromagnetic irrespective of their size or shape. In addition, these nitrogen stabilized Mn clusters carry giant magnetic moments ranging from 4 Bohr magnetons in MnN to 22 Bohr magnetons in Mn_5N. It is suggested that the giant magnetic moments of Mn_xN clusters may play a key role in the ferromagnetism of Mn doped GaN which exhibit a wide range (10K - 940K) of Curie temperatures

Anisotropic charge transport in non-polar GaN QW: polarization induced charge and interface roughness scattering

Charge transport in GaN quantum well (QW) devices grown in non-polar direction has been theoretically investigated . Emergence of anisotropic line charge scattering mechanism originating as a result of anisotropic rough surface morphology in conjunction with in-plane built-in polarization has been proposed. It has shown that in-plane growth anisotropy leads to large anisotropic carrier transport at low temperatures. At high temperatures, this anisotropy in charge transport is partially washed out by strong isotropic optical phonon scattering in GaN QW.Comment: 4 pages, 4 figure