Hot Core, Outflows and Magnetic Fields in W43-MM1 (G30.79 FIR 10)

We present submillimeter spectral line and dust continuum polarization observations of a remarkable hot core and multiple outflows in the high-mass star-forming region W43-MM1 (G30.79 FIR 10), obtained using the Submillimeter Array (SMA). A temperature of $\sim$ 400 K is estimated for the hot-core using CH$_3$CN (J=19-18) lines, with detections of 11 K-ladder components. The high temperature and the mass estimates for the outflows indicate high-mass star-formation. The continuum polarization pattern shows an ordered distribution, and its orientation over the main outflow appears aligned to the outflow. The derived magnetic field indicates slightly super-critical conditions. While the magnetic and outflow energies are comparable, the B-field orientation appears to have changed from parsec scales to $\sim$ 0.1 pc scales during the core/star-formation process.Comment: accepted, ApJ Letter

Surface plasmon enhanced silicon solar cells

Thin-film solar cells have the potential to significantly decrease the cost of photovoltaics. Light trapping is particularly critical in such thin-film crystalline silicon solar cells in order to increase light absorption and hence cell efficiency. In this article we investigate the suitability of localized surface plasmons on silvernanoparticles for enhancing the absorbance of silicon solar cells. We find that surface plasmons can increase the spectral response of thin-film cells over almost the entire solar spectrum. At wavelengths close to the band gap of Si we observe a significant enhancement of the absorption for both thin-film and wafer-based structures. We report a sevenfold enhancement for wafer-based cells at λ=1200 nm and up to 16-fold enhancement at λ=1050 nm for 1.25 μm thin silicon-on-insulator (SOI) cells, and compare the results with a theoretical dipole-waveguide model. We also report a close to 12-fold enhancement in the electroluminescence from ultrathin SOI light-emitting diodes and investigate the effect of varying the particle size on that enhancement.S. Pillai would like to acknowledge the UNSW Faculty of Engineering Research Scholarship. K.R. Catchpole acknowledges the support of an Australian Research Council fellowship

Comparative assessment of the impact of motorisation on the artisanal fisheries at Vizhinajam

The fishery statistics collected from Vizhinjam fish landing centre for seven years from 1986 to 1992 was utilised as the data for the motorisation period. The fishery data during the pre-motorisation period is taken from Luther et cd. (1982) for presenting the comparative assessment of the impact of motorisation. An Increase in the total fish catch as well as in the catch per unit effort is evident during themotorisation period. The fast accessibility to the distant fishing grounds by the motorlsed crafts, the increased number of fishing hands employed in the motorlsed units and the avEiilability of more time for actual fishing due to the time saved for rowing seem to be the major reasons for the higher catch and catch rate in the motorlsed units

On the recent Introduction of outboard engines along the Coromandal coast

Introduction of outboard engines along the Coromandal coast and Pondicherry were studied. A total number of 232 outboard engines have been introduced at 16 fish landing centres in the South Arcot District. The outboard engines are fitted exclusively to catamarans with a length range of 8-10 m operating mainly gill nets, Pannu valai and Mani valai and the encircling bag-net, Eda valai

A timeline for massive star-forming regions via combined observation of o-H2_2D+^+ and N2_2D+^+

Context: In cold and dense gas prior to the formation of young stellar objects, heavy molecular species (including CO) are accreted onto dust grains. Under these conditions H$_3^+$ and its deuterated isotopologues become more abundant, enhancing the deuterium fraction of molecules such as N$_2$H$^+$ that are formed via ion-neutral reactions. Because this process is extremely temperature sensitive, the abundance of these species is likely linked to the evolutionary stage of the source. Aims: We investigate how the abundances of o-H$_2$D$^+$ and N$_2$D$^+$ vary with evolution in high-mass clumps. Methods: We observed with APEX the ground-state transitions of o-H$_2$D$^+$ near 372 GHz, and N$_2$D$^+$(3-2) near 231 GHz for three massive clumps in different evolutionary stages. The sources were selected within the G351.77-0.51 complex to minimise the variation of initial chemical conditions, and to remove distance effects. We modelled their dust continuum emission to estimate their physical properties, and also modelled their spectra under the assumption of local thermodynamic equilibrium to calculate beam-averaged abundances. Results: We find an anticorrelation between the abundance of o-H$_2$D$^+$ and that of N$_2$D$^+$, with the former decreasing and the latter increasing with evolution. With the new observations we are also able to provide a qualitative upper limit to the age of the youngest clump of about 10$^5$ yr, comparable to its current free-fall time. Conclusions: We can explain the evolution of the two tracers with simple considerations on the chemical formation paths, depletion of heavy elements, and evaporation from the grains. We therefore propose that the joint observation and the relative abundance of o-H$_2$D$^+$ and N$_2$D$^+$ can act as an efficient tracer of the evolutionary stages of the star-formation process

Problems and prospects of marine fisheries at Lakshadweep

The live-bait fishes play a pivotal role in the development and success of the pole-and-line fishery in Lakshadweep. The total live-bait fish catch from this insular area is estimated to be 125 t in recent years. The major groups exploited at Minicoy are clupeids, caesionids and apogonids. The clupeid, Spratelloides delicatulus is the only species caught as bait in the northern islands. The major fishing areas for live-baits are Minicoy, Agatti, Suheli, Perumal Par, Bitra, Valiapani and Cheriyapani. Both meteorological and hydrographical factors influence the recruitment of migratory groups to the lagoon, while resident forms depend on the recruitment success.The Lakshadweep sea is estimated to have an annual fisher

Consultancy services in marine fisheries- A profile of technologies and experts

The ICAR system currently needs very effective partnership between the researchers and the user groups. The Central Marine Fisheries Research Institute, a premier Institute under the ICAR, has taken effective steps to introduce the services and technologies in the marine fisheries sector, achieved over the last 50 years R & D activities. With a viev/ to institutionalising transfer of technologies, the institute has constituted a Consultancy Processing Cell (CPC) in 1997 for effectively serving the needs of our clients, through the short term and long term trainings, consultancies, contract services and contract research

Marine Fish Calendar 9. Vizhinjam

Vizhinjam, an important fish landing centre in the fishery zone extending from Kollangode in the south to Valiaveli in the north spreading over a distance of 50 km on the southwest coast of India. Data collected over a period of five years, from 1981 to 1985, from the landing centre at Vizhinjam have been analysed to draw up a general fishery calendar suitable for this centre elucidating the cyclic changes in the abundance and dominance of the commercially important species/ groups of fish within a year. The data show that the annual marine fish landings (fin fish alone) at Vizhinjam ranged from 5,207.01 t in 1981 to 9,726.2 t in 1985 with the annual average landings at 6,374.41 t

Enhanced emission from Si-based light-emitting diodes using surface plasmons

Excitation of surface plasmons on metallic nanoparticles has potential for increasing the absorption and emission from thin Si devices. We report an eight-fold enhancement in electroluminescence from silicon-on-insulator light-emitting diodes at 900nm via excitation of surface plasmon resonance in silvernanoparticles, along with a redshift in the electroluminescence by 70nm by overcoating the nanoparticles with ZnS. The enhancement is due to coupling between the electromagnetic excitations of the silvernanoparticles and the waveguide modes.The Centre of Excellence for Advanced Silicon Photovoltaics and Photonics is supported under the Australian Research Council’s Centres of Excellence Scheme

Stock assessment of coastal tunas in the Indian seas

Tuna and billfish production from the Indian coastal waters, Lakshadweep and Andaman and Nicobar islands during the period 1985-'99 averaged 40,204 t. The contribution by E.affinis, Athazard, T.tonggol, K.pelamis and T.albacares (young ones) were 18,5041,6,8521,3,093 t, 3,3921 and 2,2111 respectively. Drift gill net was the major gear employed in the coastal tuna fishery. The length frequency data collected on the above species during 1990-'98 at seven centres along the Indian coast were analysed employing FiSAT programme to estimate their growth and mortality parameters, exploitation rates and relative yield per recmit