713 research outputs found
Effect of pond aeration on growth and survival of Penaeus monodon Fab.
The effect of paddle wheel aeration on shrimp growth and survival were studied at a
commercial farm at Chandipur coast of Orissa, India, at different stocking densities of
Penaeus monodon. Four different aeration patterns were adopted and evaluated. Influence
of individual aeration pattern on average survival rate was not highly significant
(p<0.05) at different stocking densities, while different aeration patterns had significant
influence (p<O.OOl) on survival rate of P. monodon. It was also estimated that 1.77 hp
(aerator) is needed for every 1000 kg shrimp biomass which corresponds to 1 hp/565 kg
biomass of shrimp. Higher growth rate was mostly observed during 63-98 days of culture,
when six 2 hp aerators were in use. Size variation in growth was higher during initial
stage of rearing, while it was reduced to significant level towards the last phase of rearing
as number of aerator and hour of operation increased
High order difference schemes for the system of two space second order nonlinear hyperbolic equations with variable coefficients
AbstractIn this paper, we develop implicit difference schemes of O(k4 + k2h2 + h4), where k > 0, h > 0 are grid sizes in time and space coordinates, respectively, for solving the system of two space dimensional second order nonlinear hyperbolic partial differential equations with variable coefficients having mixed derivatives subject to appropriate initial and boundary conditions. The proposed difference method for the scalar equation is applied for the solution of wave equation in polar coordinates to obtain three level conditionally stable ADI method of O(k4 + k2h2 + h4). Some physical nonlinear problems are provided to demonstrate the accuracy of the implementation
Composition and Stand Structure of Tropical Moist Deciduous Forest of Similipal Biosphere Reserve, Orissa, India
Impact of torrential rain on coastal ecosystem at kalpakkam, southeast coast of India
1609-1615The present study focuses on the drastic changes observed in the coastal ecosystem at Kalpakkam during flooding event due to huge rainfall that occurred in and around northern Tamil Nadu during December 2015. A significant increase in hydrological parameters (nitrate, phosphate, silicate, total nitrogen and phosphorous) was recorded as compared to previous years (2006-2014). In the present instance, the coastal water salinity which was about 19 psu was the lowest as compared to the data available since 1979. The phytoplankton population density was severely affected by the runoff. The present observed density 1.4 x 104 cells l-1 was the lowest among the available data at this coast. Availability of green algae species in the coastal waters was significantly high (10 species, 17 % of total species) as compared to previous reports. One of the most interesting features of this study was the observation of epibiosis on zooplankton in massive numbers. A comparison of previous occurrences of epibiotic relationship in plankton community with the present observation showed a staggering increase in epibiosis to 38 % of zooplankton species as compared to 5-13 % during 2008-2014
Sixth-order compact finite difference method for singularly perturbed 1D reaction diffusion problems
AbstractIn this paper, the sixth-order compact finite difference method is presented for solving singularly perturbed 1D reaction–diffusion problems. The derivative of the given differential equation is replaced by finite difference approximations. Then, the given difference equation is transformed to linear systems of algebraic equations in the form of a three-term recurrence relation, which can easily be solved using a discrete invariant imbedding algorithm. To validate the applicability of the proposed method, some model examples have been solved for different values of the perturbation parameter and mesh size. Both the theoretical error bounds and the numerical rate of convergence have been established for the method. The numerical results presented in the tables and graphs show that the present method approximates the exact solution very well
Signature of short distance physics on inflation power spectrum and CMB anisotropy
The inflaton field responsible for inflation may not be a canonical
fundamental scalar. It is possible that the inflaton is a composite of fermions
or it may have a decay width. In these cases the standard procedure for
calculating the power spectrum is not applicable and a new formalism needs to
be developed to determine the effect of short range interactions of the
inflaton on the power spectrum and the CMB anisotropy. We develop a general
formalism for computing the power spectrum of curvature perturbations for such
non-canonical cases by using the flat space K\"all\'en-Lehmann spectral
function in curved quasi-de Sitter space assuming implicitly that the
Bunch-Davis boundary conditions enforces the inflaton mode functions to be
plane wave in the short wavelength limit and a complete set of mode functions
exists in quasi-de Sitter space. It is observed that the inflaton with a decay
width suppresses the power at large scale while a composite inflaton's power
spectrum oscillates at large scales. These observations may be vindicated in
the WMAP data and confirmed by future observations with PLANCK.Comment: 17 pages, 4 figures, Extended journal version, Accepted for
publication in JCA
Empowering married young women and improving their sexual and reproductive health: Effects of the First-time Parents Project
The Population Council, in partnership with Child In Need Institute in Kolkata, Deepak Charitable Trust in Vadodara, and International Institute for Population Sciences, Mumbai, initiated the First-time Parents Project in India to develop and test an integrated package of health and social interventions to improve married young women’s reproductive and sexual health knowledge and practices, enhance their ability to act in their own interest, and expand their social support networks. The project was formulated on the hypothesis that the periods immediately following marriage and surrounding the first pregnancy and birth offer a unique and powerful entry point for improving the situation of married young women. Findings indicate that the intervention had a significant, positive net effect on most indicators reflecting married young women’s autonomy, social support networks, partner communication, and knowledge of sexual and reproductive health. However, the net effect of exposure to the intervention was mixed with regard to indicators related to gender role attitudes and attitudes toward domestic violence, as well as reproductive health practices. The experience of the intervention demonstrates that it is feasible to improve married young women’s reproductive health knowledge and practices, expand their sources of social support, and involve them in activities with peers in safe spaces outside the home, and through the process empower them in their marital and familial relationships. The report suggests that this model could also be integrated into existing NGO or government services, and could be tested for implementation on a larger scale
A novel realization of the Calogero-Moser scattering states as coherent states
A novel realization is provided for the scattering states of the -particle
Calogero-Moser Hamiltonian. They are explicitly shown to be the coherent states
of the singular oscillators of the Calogero-Sutherland model. Our algebraic
treatment is straightforwardly extendable to a large number of few and
many-body interacting systems in one and higher dimensions.Comment: 9 pages, REVTe
Observations of TeV gamma-rays from Mrk 421 during Dec. 2005 to Apr. 2006 with the TACTIC telescope
The TACTIC -ray telescope has observed Mrk 421 on 66 clear nights
from Dec. 07, 2005 to Apr. 30, 2006, totalling 202 hours of on-source
observations. Here, we report the detection of flaring activity from the source
at 1 TeV energy and the time-averaged differential -ray spectrum
in the energy range 1-11 TeV for the data taken between Dec. 27, 2005 to Feb.
07, 2006 when the source was in a relatively higher state as compared to the
rest of the observation period. Analysis of this data spell, comprising about
97h reveals the presence of a -ray signal with
daily flux of 1 Crab unit on several days. A pure power law spectrum with
exponent as well as a power law spectrum with an exponential
cutoff and are found to provide
reasonable fits to the inferred differential spectrum within statistical
uncertainties. We believe that the TeV light curve presented here, for nearly 5
months of extensive coverage, as well as the spectral information at
-ray energies of 5 TeV provide a useful input for other groups
working in the field of -ray astronomy.Comment: 13pages,4figures; Accepted for publication in Astroparticle Physic
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