Vela, its X-ray nebula, and the polarization of pulsar radiation

The recent identification of the perpendicular mode of radio polarization as the primary one in the Vela pulsar by Lai et al. (2001) is interpreted in terms of the maser mechanism proposed by Luo & Melrose (1995). We suggest that such a mechanism may also be operative for the parallel mode which opens up the possibility of accounting for all types of polarization observed in pulsars. We propose an alternative interpretation of the arcs in the nebular X-radiation observed by Pavlov et al.(2000) & Helfand et al. (2001) with the Chandra Observatory, and interpreted by the latter as an equatorial wind. We interpret the arcs as traces of the particle beams from the two magnetic poles at the shock front. We also propose that the alignment with the rotation axis of the jet-like feature bisecting the arcs is an effect of projection on the sky plane and that there is no physical jet along the axis of rotation.Comment: 7 pages, 3 figures; version 2; accepted for publication in A&

The observational evidence pertinent to possible kick mechanisms in neutron stars

We examine available observations on pulsars for evidence pertaining to mechanisms proposed to explain the origin of their velocities. We find that mechanisms predicting a correlation between the rotation axis and the pulsar velocity are ruled out. Also, that there is no significant correlation between pulsar magnetic field strengths and velocities. With respect to recent suggestions postulating asymmetric impulses at birth being solely responsible for both the spins and velocities of pulsars, single impulses of any duration and multiple extended duration impulses appear ruled out.Comment: 7 pages. Accepted for publication in Astronomy & Astrophysic

Considerations concerning fatigue life of metal matrix composites

Since metal matrix composites (MMC) are composed from two very distinct materials each having their own physical and mechanical properties, it is feasible that the fatigue resistance depends on the strength of the weaker constituent. Based on this assumption, isothermal fatigue lives of several MMC's were analyzed utilizing a fatigue life diagram approach. For each MMC, the fatigue life diagram was quantified using the mechanical properties of its constituents. The fatigue life regions controlled by fiber fracture and matrix were also quantitatively defined

Taylor the sailor

This article does not have an abstract

Status of crustacean fishery resources -Winter School on Impact of Climate Change on Indian Marine Fisheries held at CMFRI, Cochin 18.1.2008 to 7.2.2008

From the economic and industrial point of view, edible marine crustaceans consisting of shrimps, lobsters are the most important constituents of the commercial fish landings in the country. Major portion of the landings was exported in various product forms. Investigations on resources and biology of shrimps, lobsters and other important crustaceans were initiated at the CMFRI in 1947 and since then, valuable data had been collected. Information on catch and effort, composition of landings, species-wise details on age and growth, food and feeding, maturation and spawning, migration and population characteristics for shrimps, lobsters and crabs were collected from fish landing centers along the Indian coast. This voluminous database has provided a strong foundation for assessment of edible crustacean stock, so as to suggest appropriate regulatory measures for effective management of these resources. A comprehensive account on the fishery and biological characteristics on edible crustaceans, and management options for their optimum exploitation based on the research carried out by CMFRI is presented here

Commercial prospects for farming spiny lobsters

Tropical spiny lobsters are fast growing and highly adaptable to captive condition

Overview of lobster farming- Winter School on Recent Advances in Breeding and Larviculture of Marine Finfish and Shellfish

Lobsters are high valued seafood with well established export markets around the world and form extremely important fisheries in many countries. World’s production of palinurid lobsters mostly originate from Australia, New Zealand, Cuba, Brazil, South Africa, USA and Mexico. The annual world catch of lobsters is 2, 33,825 t (2005) valued at US $ 2108 million. Total landing of spiny lobsters is 71925 t (2004)

Lobster farming in India

Spiny or rock lobsters are low volume and high value fisheries which support some of the most valuable marine resource worldwide. India, earns an approximate US $ 15 million each year through export of lobsters, mostly to Southeast Asian countries and Japan, although less than, 3,000 tonnes is landed annually. The potential for increasing the yield from the wild fisheries is limited, as the stock is subjected to extreme fishing pressure and is nearing their long term equilibrium yield. Hence, the most imaginative management strategy seems to be increasing the production through population enhancement and aquaculture. Recent success in rearing the phyllosoma larvae, has significantly improved the chances of captive breeding and seed production in spiny lobsters