Distribution, abundance and biology of unicorn cod, Bregmaceros mcclellandi in the deep scattering layers of Indian Exclusive Economic Zone

In the deep scattering layer (DSL) the fishes have accounted for 5.4 % of the total (numerical) biomass. Juvenile fish belonging to different families were the most abundant component followed by Vinciguerria, myctophids, leptocephali, stomiforms, and unicorn cod. The "unicorn cod is represented by a single species, Bregmaceros mcclellandi (2.4%) in the total fish biomass. It occurred in 52 stations out of 445 IKMT stations. During day time the average number per haul was 21 where as in night hauls it was 29. The resource was fairly abundant along the northwest coast within the depth belt of 200 m. Biological studies on the size composition, feeding habits, and reproductive biology of the species were also carried out. The length ranged from 10-65 mm. The major diet consists of copepods, euphausiids, cheatognaths, ostracods and decapod larvae. Invariably the feeding intensity was low. The catch was composed of mostly females in maturity stages IV-V. The species spawns only once in a year. The fecundity ranged from 530 - 980 in fishes of 42 - 50 mm in total length

Threadfin breams and lizard fish resources in the shelf waters of the Indian EEZ

The regional and seasonal distribution and abundance of threadfin breams and lizard fish are presented as revealed by the bottom trawling operations of FORV Sagar Sampada during cruises 56-91 (1989 and 1992). The threadfin breams occurred in 49 and lizard fish in 25% of the total number of bottom trawhng stations surveyed. The most productive grounds for threadfin breams were located in the southwest coast between 8° and 15° N latitudinal zones, with the area 11775° yielding the highest average catch rate of 1794 kg/hr. Very high congregation and concentration of threadfin breams, composed mainly of Nemipterus mesoprion and N. japonicus, was observed in the southwest in 41- 80 m depth zones during southwest monsoon period. Lizard fish resources, composed mainly of Saurida tumbil and S. undosquamis were also relatively more dominant in the southwest coast than along the east coast and in the EEZ of Andaman-Nicobar islands. The size distribution of N. japonicus and A', mesoprion showed that smaller modal groups were dominant in shallower depth zones. The potential yield of threadfin breams in the southwest zone was estimated to be 2.05 x 10

Nonlinear DC-response in Composites: a Percolative Study

The DC-response, namely the $I$-$V$ and $G$-$V$ charateristics, of a variety of composite materials are in general found to be nonlinear. We attempt to understand the generic nature of the response charactersistics and study the peculiarities associated with them. Our approach is based on a simple and minimal model bond percolative network. We do simulate the resistor network with appropritate linear and nonlinear bonds and obtain macroscopic nonlinear response characteristics. We discuss the associated physics. An effective medium approximation (EMA) of the corresponding resistor network is also given.Comment: Text written in RevTEX, 15 pages (20 postscript figures included), submitted to Phys. Rev. E. Some minor corrections made in the text, corrected one reference, the format changed (from 32 pages preprint to 15 pages

Marine Fish Calendar. 4 Cochin

The article provides details about the marine fish landing at Cochin fisheries harbour, Kerala during the period 1981-1985. It was found that the majority of the landing was contributed by purse seine followed by trawlers, drift gill nets, boat seines, hooks and lines etc

Correlated conformation and charge transport in multiwall carbon nanotube - conducting polymer nanocomposites

The strikingly different charge transport behaviors in nanocomposites of multiwall carbon nanotubes (MWNTs) and conducting polymer polyethylene dioxythiophene - polystyrene sulfonic acid (PEDOT-PSS) at low temperatures are explained by probing their conformational properties using small angle X-ray scattering (SAXS). The SAXS studies indicate assembly of elongated PEDOT-PSS globules on the walls of nanotubes, coating them partially thereby limiting the interaction between the nanotubes in the polymer matrix. This results in a charge transport governed mainly by small polarons in the conducting polymer despite the presence of metallic MWNTs. At T > 4 K, hopping of the charge carriers following 1D-VRH is evident which also gives rise to a positive magnetoresistance (MR) with an enhanced localization length (~ 5 nm) due to the presence of MWNTs. However, at T < 4 K, the observation of an unconventional positive temperature coefficient of resistivity (TCR) is attributed to small polaron tunnelling. The exceptionally large negative MR observed in this temperature regime is conjectured to be due to the presence of quasi-1D MWNTs that can aid in lowering the tunnelling barrier across the nanotube - polymer boundary resulting in large delocalization.Comment: Accepted J. Phys.: Condens. Matte

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Edible oyster cultur

Charge transport properties of water dispersible multiwall carbon nanotube-polyaniline composites

The transmission electron microscopy images of in situ prepared multiwall carbon nanotubes (MWNTs) and polyaniline (PANI) composites show that nanotubes are well dispersed in aqueous medium, and the nanofibers of PANI facilitate intertube transport. Although low temperature transport indicates variable range hopping (VRH) mechanism, the dc and ac conductivity become temperature independent as the MWNT content increases. The onset frequency for the increase in conductivity is observed to be strongly dependent on the MWNT weight percent, and the ac conductivity can be scaled onto a master curve. The negative magnetoresistance is attributed to the forward interference scattering mechanism in VRH transport.Peer reviewe

Electron spin resonance studies in the doped polyaniline PANI-AMPSA: evidence for local ordering from linewidth features

X-band electron spin resonance (ESR) of polyaniline (PANI) doped with 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPSA), at conductivity values of 90, 4, and 0.2 S?cm, has been investigated from 300 to 5 K. Free-standing films (30-40 &#181;m thick) of PANI were prepared by solution casting method. The spectra consist of two signals, one is broad (?60 G) and the other is narrow (?10 G), at nearly the same resonance field. The temperature variation of ESR susceptibility indicates a stronger Pauli component in the broad line signal, as compared to the narrow signal, at all values of conductivity. Both linewidths are independent of the presence of O<SUB>2</SUB>. The temperature variation of linewidths is explained in terms of the quasi-two-dimensional (Q2D) model. These results suggest that in some regions the doped PANI chains have self-assembled Q2D structure, and the presence of a significant Pauli susceptibility indicates that the charge carriers are highly delocalized in these Q2D regions