Acoustic and gravity waves in the neutral atmosphere and the ionosphere, generated by severe storms

Gravity waves in the neutral atmosphere and their propagation in the ionosphere and the study of infrasonic signals from thunder were investigated. Doppler shifts of the order of 0.1 Hz are determined and they provide high-resolution measurements of the movements in the ionosphere. By using an array of transmitters with different frequencies and at different locations, the horizontal and vertical propagation vectors of disturbances propagating through the ionosphere are determined

Novel Studies on the \eta' Effective Lagrangian

The effective Lagrangian for \eta' incorporating the effect of the QCD \theta-angle has been developed previously. We revisit this Lagrangian and carry out its canonical quantization with particular attention to the test function spaces of constraints and the topology of the \eta'-field. In this way, we discover a new chirally symmetric coupling of this field to chiral multiplets which involves in particular fermions. This coupling violates P and T symmetries. In a subsequent paper, we will evaluate its contribution to the electric dipole moment (EDM) of fermions. Our motivation is to test whether the use of mixed states restores P and T invariance, so that EDM vanishes. This calculation will be shown to have striking new physical consequences.Comment: 14 pages, 1 figure; V2: NEW TITLE; revised version to be published in JHEP; references adde

The eels and eel fisheries of India

Traditionally marketable species of eels are caught from conventional fishing grounds of northwest and northeast coasts of India and are largely a by-catch

Hooks and Line Fishery Resources of India

Of the several types of traditional fishing methods,the hooks and line formed one of the most dominant and economically viable fishing technique to exploit large pelagic, column and demersal preda tor fishes, There are about 57,000 hooks and line units in India, which is the second dominant gear for marine fishing, next to drift/gill net, with the maximum number in Tamil Nadu (39%) followed by Orissa (27%) and Andhra Pradesh (19%) (Anon, 1981

Distribution and abundance of the genus Vinciguerria (Gonostomatidae) in the DSL of Indian EEZ with a note on the biology of Vinciguerria nimbaria

In the DSL fish biomass one of the dominant genus was Vinciguerria, represented by three species such as V. nimbaria, V. attenuata and V. poweriae. The occurrence of Vinciguerria was frequent in nortliwest and southwest area of EEZ at varying depths. The average number per haul in Isaac Kidd mid water trawl (IKMT) was 149 in day and 191 in night collection. Vinciguerria nimbaria has accounted for more than 95% of the total catch of the genus. Its total length varied from 10-56 mm. The length weight relationship is log W = -5.5691 + 3.1676 log I. Invariably the species fed on copepods, ostracods, cladocerans, appendicularians euphausiids, chaetognaths, fish larvae etc. with variations in feeding intensity during day and night. About 92 % of the catch belonged to mature fishes. The species spawns only once in a year and the fecundity ranged from 140 to 770 ova in fishes of 34 - 55 mm total length

Topology in Physics - A Perspective

This article, written in honor of Fritz Rohrlich, briefly surveys the role of topology in physics.Comment: 16pp, 2 figures included (encapsulated postscript

Impact of coastal bottom trawling on target and non- target resources along the south west coast of India

The trawling is carried out almost throughout the year in the inshore water except for peak monsoon months. Their nonoperation is chiefly due to the unfavourable sea conditions or bans imposed by the governments as in Kerala, Tamilnadu, Andhra Pradesh or socially self-imposed ban as in Karnataka. The excessive fishing pressure exerted by the mechanized / motorized sector in a climatically limited coastal habitat up to a depth of about 50 m have not only affected the sustenance of some easily vulnerable resources, but also challenged the very existence of some shell fishes, fin fishes and bottom organisms, including the biota which are non-edible to man but vital in the food web of all exploitable resources. The present account pertains to the impact of the gear along the south-west coast (Karnataka and Kerala) trawling grounds preferably on the non- target by catch

Need for protecting the non-edible benthic biota of the inshore waters for the benefit of the coastal resources and the fishing industry

Over the past five decades, the Indian marine fisheries have been subjected to modifications and development. The modifications have transformed a subsistence oriented traditional fisheries into a market-oriented semiindustrial sector, with tremendous growth in fish production which in turn has increased the total revenue in terms of national as well as foreign currency turn over. The fast development of modern technologies in the harvesting sector, coupled with the rising demands for Indian marine products abroad have paved the way for reaping incessantly the vast expanses of coastal waters sometimes even beyond the sustaining capacity of the habitat. Inspite of these advances, it is disheartening to note that our present marine fish production has been swinging around 1.2 to' 2.3 million tonnes during the past two decades, with only marginal annual increase even with increased fishing pressures, new innovations, diversification, industrialisation, etc. Assessment of the stocks of the major fish resources in the exploited grounds have categorically revealed that the stocks of target groups/species of relatively high value and easily vulnerable ones are on the verge of overexploitation and therefore warrant immediate management measures. Today's Indian marine fisheries thus face challenging problems in trying to achieve the kind of sustainability that will assure its own long-range survival

Poincar\'e Invariant Quantum Field Theories With Twisted Internal Symmetries

Following up the work of [1] on deformed algebras, we present a class of Poincar\'e invariant quantum field theories with particles having deformed internal symmetries. The twisted quantum fields discussed in this work satisfy commutation relations different from the usual bosonic/fermionic commutation relations. Such twisted fields by construction are nonlocal in nature. Despite this nonlocality we show that it is possible to construct local interaction Hamiltonians which satisfy cluster decomposition principle and are Lorentz invariant. We further illustrate these ideas by considering global SU(N) symmetries. Specifically we show that twisted internal symmetries can significantly simplify the discussion of the marginal deformations (\beta-deformations) of the N=4 SUSY theories.Comment: 27 pages, Typos Corrected, Text and Conclusions Unchanged, Version published in JHE