Preliminary observations on the biology of Chirocentrus dorab Forsk

The flourishing dorab fishery along the coasts of Palk Bay and Gulf of Mannar in Ramnad District in South India is constituted chiefly of Chirocentrus dorabJ probably the only clupeoid fish growing to a size of nearly 100 crn

The Oil Sardine

In the marine fisheries map of India pelagic fishes dominated by clupeoids undoubtedly occupy an important place by virtue of the relative magnitude of their fishery. Clupeoids, in general, constitute about a third of the marine fish caught in India and within this group oil sardine {Sardinella longiceps Valenciennes) known as "Mathi" in Malayalam "Boothai" in Kannada and "Tarali" or "Haid" in Marathi, ranks first. Out of a total of 815,120 tonnes of marine fishes landed in 1965, oil sardine alone accounted for 253,302 tonnes forming 31. 69

On the breeding habits of the ribbon fish Trichiurus haumela (Forsk.)

Although ribbon fishes provide an important fishery along the east a nd west coast; of India, their shoaling, breeding and spawning habits have not been investigated in detail. VenkatramanG gave a short account of the feeding habits of ribbon fishes of the Malabar coast, and Chidambaram and Venkatraman1 dealt with the natural history of ribbon fishes

The AGN and Gas Disk in the Low Surface Brightness Galaxy PGC045080

We present radio observations and optical spectroscopy of the giant low surface brightness (LSB) galaxy PGC 045080 (or 1300+0144). PGC 045080 is a moderately distant galaxy having a highly inclined optical disk and massive HI gas content. Radio continuum observations of the galaxy were carried out at 320 MHz, 610 MHz and 1.4 GHz. Continuum emission was detected and mapped in the galaxy. The emission appears extended over the inner disk at all three frequencies. At 1.4 GHz and 610 MHz it appears to have two distinct lobes. We also did optical spectroscopy of the galaxy nucleus; the spectrum did not show any strong emission lines associated with AGN activity but the presence of a weak AGN cannot be ruled out. Furthermore, comparison of the H$\alpha$ flux and radio continuum at 1.4 GHz suggests that a significant fraction of the emission is non-thermal in nature. Hence we conclude that a weak or hidden AGN may be present in PGC 045080. The extended radio emission represents lobes/jets from the AGN. These observations show that although LSB galaxies are metal poor and have very little star formation, their centers can host significant AGN activity. We also mapped the HI gas disk and velocity field in PGC 045080. The HI disk extends well beyond the optical disk and appears warped. In the HI intensity maps, the disk appears distinctly lopsided. The velocity field is disturbed on the lopsided side of the disk but is fairly uniform in the other half. We derived the HI rotation curve for the galaxy from the velocity field. The rotation curve has a flat rotation speed of ~ 190 km/s.Comment: Paper contains 14 figures and 4 tables. Figures 8, 10 (color) and 13 supplied separately. Accepted for publication in MNRA

ON CERTAIN TOPOLOGICAL INDICES OF BENZENOID COMPOUNDS

Drug discovery is mainly the result of chance discovery and massive screening of large corporate libraries of synthesized or naturally-occurring compounds. Computer aided drug design is an approach to rational drug design made possible by the recent advances in computational chemistry in various fields of chemistry, such as molecular graphics, molecular mechanics, quantum chemistry, molecular dynamics, library searching, prediction of physical, chemical, and biological properties.  The structure of a chemical compound can be represented by a graph whose vertex and edge specify the atom and bonds respectively. Topological indices are designed basically by transforming a molecular graph into a number. A topological index is a numeric quantity of a molecule that is mathematically derived from the structural graph of a molecule. In this paper we compute certain topological indices of pyrene molecular graph. The topological indices are used in quantitative structure-property relationships (QSPR) and quantitative structure-activity relationships (QSAR) studies.Â

The oil sardine fishery in the Mangalore zone during the seasons 1963—64 and 1967—68

The oil sardine fishery in the Mangalore zone showed an upward trend from 1963-64 to 1966-67 when the catches increased seven-fold from 52 to 386 tonnes, which was followed by a slight decline to 243 tonnes in 1967-68. Among the gears operated for the oil sardine fishery, the highest catch-per-unit-efFort values were obtained for the cast net, chala bale and rampant. The best catches of oil sardine were obtained during September-December period when temperature and salinity values ranged 25.5 to 28.6''C and 28.98 to 34.36 %, respectively. The length frequency studies indicate that the oil sardine attains a size of about 100-110 mm during the first year, 150-160 mm during the second year and 175-180 mm during the third year of its appearance. The fishery during the various years was supported by difierent year classes. One and two-year olds dominated in 1963-64, 1966-67 and 1967-68 and one-year olds in 1964-65. In 1965-66, one-year olds formed the mainstay of the fishery, although the two-year olds also contributed from December onwards. O-year class was seen entering the fishery during the months of August and September in 1964-65, 1965-66 and 1966-67, as also in October and again in January and February during 1967-68. Two or more broods have been observed to enter the fishery during certain years. Judged from the rate of growth and the size attained by the smaller size groups composing the O-year class, the interval between the entries of various broods has been observed to vary from one to three months. The estimated average rate of decrease diu'ing the five-year period worked out to 0.72, the instantaneous rate of mortality being 1.27

Local Invariants and Pairwise Entanglement in Symmetric Multi-qubit System

Pairwise entanglement properties of a symmetric multi-qubit system are analyzed through a complete set of two-qubit local invariants. Collective features of entanglement, such as spin squeezing, are expressed in terms of invariants and a classifcation scheme for pairwise entanglement is proposed. The invariant criteria given here are shown to be related to the recently proposed (Phys. Rev. Lett. 95, 120502 (2005)) generalized spin squeezing inequalities for pairwise entanglement in symmetric multi-qubit states.Comment: 9 pages, 2 figures, REVTEX, Replaced with a published versio