Landing of turtle

A green turtle, Chelonia mydas was landed at Dhoniapete near Vishakhapatnam on 10 February 1994 by a bottom set gill net. The turtle was 68 cm in length, 55 cm in width and weighed 42 kg

Oil sardine fishery along Srikakulam district, Andhra Pradesh

The Indian oil sardine, Sardinella longiceps as a non conventlonal resource has become one of the Important exploited fishery resources along Andhra Pradesh coast In recent years contributing on an average 3,000 t annually during the period 1979-'83. During July 1994 - July 1995, unprecedented heavy landings of oil sardine were observed in most of the fish landing centres along Srikakulam District of Andhra Pradesh and were exploited by monofilament gill nets, bay nets and shore seines

Study of dynamics in pentachlorophenol in the solid state by 1D Nuclear Quadrupole Resonance exchange spectroscopy

The paper reports studies of the dynamic process in pentachlorophenol (PCP) in the solid state by one-dimensional Nuclear Quadrupole Resonance (NQR) exchange spectroscopy employing shaped rf pulses. Pentachlorophenol exhibits intramolecular hydrogen bonding between the hydroxyl proton and one of the o-chlorines. Reorientation of the hydrogen bond with migration of the hydroxyl proton from one o-chlorine to the other is possible in a wide temperature range. In this process the two o-chlorines are exchanged; at the same time this implies the exchange of the two m-chlorines as well, which we have chosen to monitor, modeling it as a two-site exchange process. A detailed analysis of the appropriate Bloch-McConnell equation is performed to formulate the relevant kinetic matrix. The exchange pulse sequence implemented by us involves suitably modulated shaped RF pulses to achieve simultaneous on-resonance excitation of the two exchanging sites. This approach results in a clear definition of the exchange time window and requires only a short experiment time. Kinetic parameters, namely, the spin-lattice relaxation rate and the exchange rate are deduced from the experimental signal intensities. Variable temperature measurements in the range 213 K-318 K have been carried out to extract the activation parameters as well

Nuclear quadrupole resonance exchange spectroscopy with shaped radiofrequency pulses

Recent work on the nuclear quadrupole resonance (NQR) investigation of molecular dynamics in the solid state has relied on 2D methods. We report our studies of dynamic processes by 1D shaped pulse NQR spectroscopy. Significant advantages include considerably shorter experimental duration, clear definition of the exchange time window, and avoidance of off-resonance effects. The reorientation of the Cl3C group in polycrystalline chloral hydrate [Cl3C-CH(OH)2] is considered as a test case. This may be modelled as a three-site exchange process. An analysis of the generalised Bloch-McConnell equation is performed to formulate the kinetic matrix. The present approach involves simultaneous excitation of the sites that undergo chemical exchange by employing a suitably modulated shaped RF pulse, followed by a mixing time, and finally a suitable read pulse for signal detection. The experimental signal intensities are plotted against the mixing time to extract the kinetic parameters, i.e. the exchange rate and the spin-lattice relaxation rate. Variable temperature measurements are carried out to determine the activation parameters. Short experiment times are possible in our 1D mode, enabling a large number of runs to be readily performed as a function of mixing time and temperature. The kinetic and activation parameters obtained in the case of chloral hydrate are in good agreement with recent literature values

High resolution solution state double quantum spectroscopy of two-spin-1 AX systems and mimics

Double quantum spectroscopy (DQS) of the two-spin-1 AX system in the liquid state is investigated theoretically. The two kinds of double quantum coherence (DQC) that arise are studied and expressions are given for their evolution under weak scalar coupling and chemical shifts. A one-dimensional double quantum J (DQJ) filter sequence for the separation of the two kinds of DQC is introduced. Analytical expressions are given for the spin response to the general two-dimensional DQS sequence, for an arbitrary reconversion pulse flip angle β. A detailed investigation of the coherence transfer (CT) amplitudes has been carried out by computer simulation of CT amplitudes as a function of β. The differences in the behaviour of CT amplitudes of one-spin DQC, 'outer' and 'central' components of two-spin DQCs are discussed. Optimum flip angles for maximizing sensitivity of N-type, P-type and pure phase double quantum spectra of this system are deduced. The detailed predictions are borne out by recently published experimental work on two-spin-1 AX systems, as well as our studies on a mimic arrangement, viz., a spin-½A2X2 system

<SUP>1</SUP>H and <SUP>19</SUP>F dynamic nuclear polarization studies at X-band: <SUP>19</SUP>F differential enhancements

X-band dynamic nuclear polarization (DNP) measurements on 1H and 19F nuclei in 1,4-bis(trifluoromethyl)benzene, 1,2,4-trifluorobenzene and 19F nuclei in octafluorotoluene are reported. The free radical used in all these cases is tri-t-butylphenoxyl. Chemically shifted fluorines have been resolved and clear differential 19F DNP trends have been established in these systems. Q-enhancement corrections to ultimate-ultimate enhancement values are discussed. Three theoretical models of the radical-solvent interaction involving, respectively, transfer of an electron spin, M.O. treatment of solvent-radical interaction at separations around the van der Waals distance, and exchange polarization of the solvent molecule are reported. The latter, treated as a closed-shell perturbation in the molecular orbital framework, leads to an sp&#963; polarizability parameter which reflects the present experimentally observed 19F DNP trends reasonably well. Apart from the present work, the only other experimental results on 19F differential DNP are those of Dwek et al. at Q-band and their results have also been satisfactorily interpreted in terms of our sp&#963; polarizability approach

Mass entanglement of dolphins in a shore seine near Balaramapuram. Srikakulam District, Andhra Pradesh

On 14-10-'97 nine dolphins locally called 'ganupuli' were entangled in a shoreseine operated between Balaramapuram and Srikuurman-Matchllesam landing centres of Srikakulam District, Andhra Prades

Improvement in non-mechanised fishing using 'moravala'

The catch by this net is very much higher than any other gear operatedby non-mechanised crafts and is roughly estimated to be in the ratio of 2:1. The Moraval is a large net of 34 x 34 m2. It is considerably light in weight, of about 40 to 45 kg and hence it can be easily transported and operated quickly. Thereby facilitating more hauls a day. Only eight men are needed to operate this net from a catamaram.The dominating fish caught in Moravala include Mackerels, Sardines, Mullets, Silverbellies (Ponyfishes), penaid prawn

DFT Study of Planar Boron Sheets: A New Template for Hydrogen Storage

We study the hydrogen storage properties of planar boron sheets and compare them to those of graphene. The binding of molecular hydrogen to the boron sheet (0.05 eV) is stronger than that to graphene. We find that dispersion of alkali metal (AM = Li, Na, and K) atoms onto the boron sheet markedly increases hydrogen binding energies and storage capacities. The unique structure of the boron sheet presents a template for creating a stable lattice of strongly bonded metal atoms with a large nearest neighbor distance. In contrast, AM atoms dispersed on graphene tend to cluster to form a bulk metal. In particular the boron-Li system is found to be a good candidate for hydrogen storage purposes. In the fully loaded case this compound can contain up to 10.7 wt. % molecular hydrogen with an average binding energy of 0.15 eV/H2.Comment: 19 pages, 7 figures, and 3 table

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy