Population eruption of sunset shell Siliqua radiata (Linnaeus, 1758) along Versova beach in Mumbai

Sudden population eruption of Siliqua radiata during monsoon months (June-August 2008) was observed along Versova beach in Mumbai. Relationship between shell length (SL) and total weight (TW) was TW = 0.0001137 * SL 2.67922, shell length (SL) and meat weight (MW) was MW = 0.0000237 * SL 2.91756. S. radiata had isometric growth. The average density was estimated as 14 per square meter and the biomass was 153 g.m-2. The proportion of meat was 60%. Analysis of meat showed high amount of heavy metals namely copper, cadmium and arsenic

Quantized Orbits and Resonant Transport

A tight binding representation of the kicked Harper model is used to obtain an integrable semiclassical Hamiltonian consisting of degenerate "quantized" orbits. New orbits appear when renormalized Harper parameters cross integer multiples of $\pi/2$. Commensurability relations between the orbit frequencies are shown to correlate with the emergence of accelerator modes in the classical phase space of the original kicked problem. The signature of this resonant transport is seen in both classical and quantum behavior. An important feature of our analysis is the emergence of a natural scaling relating classical and quantum couplings which is necessary for establishing correspondence.Comment: REVTEX document - 8 pages + 3 postscript figures. Submitted to Phys.Rev.Let

Spiders for rank 2 Lie algebras

A spider is an axiomatization of the representation theory of a group, quantum group, Lie algebra, or other group or group-like object. We define certain combinatorial spiders by generators and relations that are isomorphic to the representation theories of the three rank two simple Lie algebras, namely A2, B2, and G2. They generalize the widely-used Temperley-Lieb spider for A1. Among other things, they yield bases for invariant spaces which are probably related to Lusztig's canonical bases, and they are useful for computing quantities such as generalized 6j-symbols and quantum link invariants.Comment: 33 pages. Has color figure

Study on Basic Mechanism of Reactive Armour

Two basic mechanisms which operate in the functioning of reactive armour are presented. Both the explosive effect and cutting of metal plates by a jet have been investigated. The angle of attack and the confinement of the explosive have been found most significant factors in reducing the penetrating power of the jet. The effect of detonating explosives has been investigated with radiography. Some of the significant effects, like detonation of explosive by the impact of the jet, expansion of covering plates, disturbance in coherence and reduction in the penetration of the jet have been observed. It is found that the jet penetration in a stack of mild steel plates is reduced to 30 per cent of its blank penetration in present set-ups. A theoretical model has been conceived to study the interaction of moving plates and the jet. The critical thickness and surface cut in plates have been calculated

Fishermen’s awareness to save a ‘Blue-ringed angel fish’ at Versova fishing village, Mumbai

Fishermen from Versova fishing village surprisingly caught a live Blue-ringed angel fish, Pomacanthus annularis (Bloch, 1787) in their trawl catch. The fish measured about 300 mm in total length and was in a very healthy condition. The fish was later taken to land and reared in a container containing seawater. On retrieving its health after a month the fish was released back to the sea. This gesture has contributed to the rehabilitation and conservation of such beautiful coral fish

Synthesis of novel 3-arylcyclopenta[c]quinolines via acid-induced domino cyclization of 2-arylamino-2-methylthioethenyl 2-arylcyclopropyl ketones

A novel acid-induced domino cyclization of N,S-anilinoacetals of type 3 derived from 2- arylcyclopropyl ketones, is reported which yields a wide range of substituted- and fused- 3- arylcyclopenta[c]quinolines 6 with concomitant formation of a cyclopentane and a quinoline ring

Influence of grain-refiner addition on the morphology of fe-bearing intermetallics in a semi-solid processed Al-Mg-Si alloy

© The Minerals, Metals & Materials Society and ASM International 2013The three-dimensional morphologies of the Fe-bearing intermetallics in a semisolid-processed Al-Mg-Si alloy were examined after extracting the intermetallics. α -AlFeSi and β-AlFeSi are the major Fe-bearing intermetallics. Addition of Al-Ti-B grain refiner typically promotes β-AlFeSi formation. β-AlFeSi was observed with a flat, plate-like morphology with angular edges in the alloy with and without grain refiner, whereas α -AlFeSi was observed as "flower"-like morphology in the alloy with grain refiner. © 2013 The Minerals, Metals & Materials Society and ASM International

Surface effects on nanowire transport: numerical investigation using the Boltzmann equation

A direct numerical solution of the steady-state Boltzmann equation in a cylindrical geometry is reported. Finite-size effects are investigated in large semiconducting nanowires using the relaxation-time approximation. A nanowire is modelled as a combination of an interior with local transport parameters identical to those in the bulk, and a finite surface region across whose width the carrier density decays radially to zero. The roughness of the surface is incorporated by using lower relaxation-times there than in the interior. An argument supported by our numerical results challenges a commonly used zero-width parametrization of the surface layer. In the non-degenerate limit, appropriate for moderately doped semiconductors, a finite surface width model does produce a positive longitudinal magneto-conductance, in agreement with existing theory. However, the effect is seen to be quite small (a few per cent) for realistic values of the wire parameters even at the highest practical magnetic fields. Physical insights emerging from the results are discussed.Comment: 15 pages, 7 figure

Relationship between body size and certain breeding behavior in selected species of Elasmobranchs off Mumbai

Social organization in elasmobranchs is complex and poorly understood. In India, no specific studies on the behaviour of this resource have been published. Breeding behavior in six species of sharks, two species of skates and three species of rays were deduced from length frequency data in relation to body size and sex. The species of sharks investigated are Scoliodon laticaudus, Rhizoprionodon acutus, Carcharhinus macloti, Carcharhinus sorrah, Carcharhinus limbatus, Loxodon macrorhinus and Sphyrna lewini. The species of skates observed were Rhinobatos annandalei and Rhyncobatus djiddensis and rays were Himantura imbricata, Himantura alcockii and Gymnura japonica. Based on the present observations mating areas, pupping and nursery grounds for juveniles, segregation and aggregation of adults were recorded