Kerr-Schild type initial data for black holes with angular momenta

Generalizing previous work we propose how to superpose spinning black holes in a Kerr-Schild initial slice. This superposition satisfies several physically meaningful limits, including the close and the far ones. Further we consider the close limit of two black holes with opposite angular momenta and explicitly solve the constraint equations in this case. Evolving the resulting initial data with a linear code, we compute the radiated energy as a function of the masses and the angular momenta of the black holes.Comment: 13 pages, 3 figures. Revised version. To appear in Classical and Quantum Gravit

Economic loss assessment on juvenile fish catch due to forced non-selectivity in a selective fishing gear, gillnet along Mumbai coast, India

A study on quantity and value of juvenile fish landings was carried out in the gillnet fishery of three selected landing centers along Mumbai coast viz., Versova, Cuff Parade and Mahim in India using Out board motors (OBM), Inboard motors (IBM) and non-motorised gillnetters respectively. The data on the quantity and value of landed juveniles were collected and analysed to reach a consensus on the gross economic loss on account of juvenile fishing. A bio-economic model was used to estimate economic loss due to juvenile fishing of 18 commercially important species of finfish and shellfish. A huge economic loss was recorded due to fishing of juveniles of 18 species by three different gillnet sectors. The analysis indicated that IBM gillnetters at Cuff Parade incurred maximum loss of Rs. 62.26 crores with major contribution from juveniles of seerfish followed by non-motorised gillnetter (Rs.29.98 crores) at Mahim and 25.33 crores in OBM gillnetters at Versova

Nuclear Reaction Rates in a Plasma

The problem of determining the effects of the surrounding plasma on nuclear reaction rates in stars is formulated ab initio, using the techniques of quantum statistical mechanics. We derive a result that expresses the complete effects of Coulomb barrier penetration and of the influence of the surrounding plasma in terms of matrix elements of well defined operators. We find that possible "dynamical screening" effects that have been discussed in the literature are absent. The form of our results suggests that an approach that relies on numerical calculations of the correlation functions in a classical Coulomb gas, followed by construction of an effective two body potential and a quantum barrier penetration calculation, will miss physics that is as important as the physics that it includes.Comment: 66 pages, revtex, Errors Fixed, Explanation Adde

The Differential Efficiency of Chlorella vulgaris and Oscillatoria sp. to Treat the Municipal Wastewater

The utilization of microalgae to treat wastewater becomes an alternative biological wastewater treatment technique worldwide because of its low cost and environmental clean. Chlorella vulgaris and Oscillatoria sp. were cultured in municipal wastewater under controlled laboratory conditions with continuous light illumination and aeration. Physical properties (pH, TDS and Salinity), and nutrient contents (ammonia, nitrite and total phosphorus)were measured in the raw wastewater. Growth rates of the cultured species in terms of optical densities and cell counts, nutrient salts removal efficiencies were measured during the experimental durations after; 24, 48, 72, 96 , 120 and 144hrs. Lipids, proteins and carbohydrates contents were also evaluated after 144hrs. The recorded optical density of Chlorella vulgaris was 0.188±0.01 at 680 nm and 0.17±0.01 at 750 nm after 24hrs then increased to 1.45±0.002 at 680nm and 1.43±0.01 at 750nm at the end of 120hrs, meanwhile the optical density of Oscillatoria sp. was increased from 0.132±0.01 at 680 nm and 0.102±0.01 at 750 nm after 24hrs to 1.054±0.004 at 680 nm and 0.99±0.002 at 750 nm at the end of 120hrs of the experiment. On the other hand, the cell count of Chlorella vulgaris was enriched from 6.8±2.2 cell/ml after 24hrs to 720±120 cell/ml at the end of 120h of the culturing. Overall, efficiencies of nutrients removal were 99.426%, 100% and 82.211% for ammonia, nitrite and total phosphorus respectively at the end of 120hrs of Chlorella vulgaris culturing, while Oscillatoria sp nutrient removal efficiencies recorded 98.125%, 100% and 84.718% for ammonia, Nitrite and total phosphorus respectively. Chlorella vulgaris biomass was estimated 26.66±7.5% lipid 35.1±1.6% protein and 29.34±3.25% carbohydrate, however Oscillatoria sp. biomass was estimated 11.76±0.79% lipids, 32.9±1.92% protein and 27.36±3.78% carbohydrates. Keywords: municipal Wastewater, Chlorella vulgaris, Oscillatoria sp., nutrient removal, biochemical parameters

Incompressible Turbulence as Nonlocal Field Theory

It is well known that incompressible turbulence is nonlocal in real space because sound speed is infinite in incompressible fluids. The equation in Fourier space indicates that it is nonlocal in Fourier space as well. Contrast this with Burgers equation which is local in real space. Note that the sound speed in Burgers equation is zero. In our presentation we will contrast these two equations using nonlocal field theory. Energy spectrum and renormalized parameters will be discussed.Comment: 7 pages; Talk presented in Conference on "Perspectives in Nonlinear Dynamics (PNLD 2004)" held in Chennai, 200

Sources of UHECRs in view of the TUS and JEM-EUSO experiments

The origin of ultra-high-energy cosmic rays (UHECRs) is one of the most intriguing problems of modern cosmic ray physics. We briefly review the main astrophysical models of their origin and the forthcoming orbital experiments TUS and JEM-EUSO, and discuss how the new data can help one solve the long-standing puzzle.Comment: 4 pages; prepared for ECRS-2012 (http://ecrs2012.sinp.msu.ru/); v2: a reference adde

Gamma-Ray Bursts from Neutron Star Kicks

The idea that gamma-ray bursts might be a kind of phenomena associated with neutron star kicks was first proposed by Dar & Plaga (1999). Here we study this mechanism in more detail and point out that the neutron star should be a high speed one (with proper motion larger than $\sim 1000$ km/s). It is shown that the model agrees well with observations in many aspects, such as the energetics, the event rate, the collimation, the bimodal distribution of durations, the narrowly clustered intrinsic energy, and the association of gamma-ray bursts with supernovae and star forming regions. We also discuss the implications of this model on the neutron star kick mechanism, and suggest that the high kick speed were probably acquired due to the electromagnetic rocket effect of a millisecond magnetar with an off-centered magnetic dipole.Comment: 12 pages, no figures, ApJ in press (minor revision with respect to Version 2