2,463 research outputs found

    Ecology and biodiversity of open sea cage farm at Mandapam, India

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    Farming of marine fin and shellfish species is an age old practice across the globe to augment the seafood demand and to supplement the rich protein food. Fin fish mariculture in India has been a recent initiative and the Central Marine Fisheries Research Institute was successful in developing captive breeding and seed production technique for cobia (Rachycentron canadum) and silver pompano (Trachinotus blochii). The open sea cages are particularly advantageous for maintaining the brood stock of potential species for captive breeding. However, the ecology of the cage farming sites is of paramount importance and should be conducive for the survival, health and growth of fishes that are farmed. In the present study, an attempt was made to understand the ecology and biodiversity of the cage farming area at Mandapam in Gulf of Mannar, south-east coast of India

    Capillary Filling of Anodized Alumina Nanopore Arrays

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    The filling behavior of a room temperature solvent, perfluoromethylcyclohexane, in approximately 20 nm nanoporous alumina membranes was investigated in situ with small angle x-ray scattering. Adsorption in the pores was controlled reversibly by varying the chemical potential between the sample and a liquid reservoir via a thermal offset, Δ\DeltaT. The system exhibited a pronounced hysteretic capillary filling transition as liquid was condensed into the nanopores. These results are compared with Kelvin-Cohan theory, with a modified Derjaguin approximation, as well as with predictions by Cole and Saam.Comment: 4 pages, 3 figures, pre-proof

    Deleting the IF1-like ζ subunit from Paracoccus denitrificans ATP synthase is not sufficient to activate ATP hydrolysis

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    In oxidative phosphorylation, ATP synthases interconvert two forms of free energy: they are driven by the proton motive force across an energy-transducing membrane to synthesize ATP and displace the ADP/ATP ratio from equilbrium. For thermodynamically-efficient energy conversion they must be reversible catalysts. However, in many species ATP synthases are unidirectional catalysts (their rates of ATP hydrolysis are negligible), and in others mechanisms have evolved to regulate or minimize hydrolysis. Unidirectional catalysis by Paracoccus denitrificans ATP synthase has been attributed to its unique ζ subunit, which is structurally analogous to the mammalian inhibitor protein IF1. Here, we used homologous recombination to delete the ζ subunit from the P. denitrificans genome and compared ATP synthesis and hydrolysis by the wild-type and knockout enzymes in inverted membrane vesicles and the F1-ATPase subcomplex. ATP synthesis was not affected by loss of the ζ subunit, and the rate of ATP hydrolysis increased by less than two fold, remaining negligible in comparison to the rates of the Escherichia coli and mammalian enzymes. Therefore, deleting the P. denitrificans ζ subunit is not sufficient to activate ATP hydrolysis. We close by considering our conclusions in the light of reversible catalysis and regulation in ATP synthase enzymes.This work was funded by the Medical Research Council (grant number U105663141 to J.H.)

    Abdominal wall endometriosis: accuracy of the diagnostic triad

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    Background: Endometriosis is the presence of endometrial glands and stroma outside the uterine cavity and musculature. The objectives were to study the prevalence, the clinic-pathological presentation and the accuracy of the criteria for diagnosis of abdominal wall endometriosis.Methods: This is a retrospective observational study done at a tertiary hospital. The study was approved by the ethics committee and the IRB. Data was retrieved from computer generated medical records. Specificity, sensitivity and likelihood ratio along with univariate and multivariable penalized logistic regression analysis of each presenting symptom were done.Results: Of the 493 cases with genital endometriosis, 45 cases had AWE diagnosed clinically giving a prevalence of 8.3%. Histological diagnosis of AWE was made in 41, while 4 had suture granuloma. Pain, swelling and previous LSCS had sensitivity of 71%, specificity of 100% and the likelihood ratio was 0.29. The presentation was within 6 years after the index surgery of Caesarean section, with the odds ratio of having endometriosis of 19 (95% CI 1.7- 1595) and the P value of 0.016.Conclusions: The diagnostic triad of previous caesarian section with swelling and pain at the scar site should prompt the possibility of AWE. However, previous LSCS was the only factor that contributed to the presence of abdominal wall endometriosis.

    Coral reef fishes of Gulf of Mannar, S.E of India

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    The coral reef ecosystem supports a wide variely of flora and fauna and Gulf of Mannar is one of its kind, located in the south-east of India. It comprises 21 islands along the 140 km stretch between Tuticorin and Rameswaram

    Type I D-branes in an H-flux and twisted KO-theory

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    Witten has argued that charges of Type I D-branes in the presence of an H-flux, take values in twisted KO-theory. We begin with the study of real bundle gerbes and their holonomy. We then introduce the notion of real bundle gerbe KO-theory which we establish is a geometric realization of twisted KO-theory. We examine the relation with twisted K-theory, the Chern character and provide some examples. We conclude with some open problems.Comment: 23 pages, Latex2e, 2 new references adde

    Studies on Composite Extrudable Propellant with varied Burning Rate Pressure Index 'n'

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    This paper discusses the development of composite propellantextrusion technique and the study of burning rate pressure indices nwith respect to compositional variations. The n is found to vary from0.35 to plateau and plateau to mesa by suitable compositionalmodifications. Compositional influence on burning rate with specificreference to plateau and mesaburning additives is described. Detailsof the process parameters like fluidity of the slurry, extrusion pressure,extrusion rate and die-swell are presented. This propellant is based onISRO-CTPB binder using ISRO-AP as oxidizer. Ammonium perchlorate (AP) particle size variation and inclusion of additives likePVC, lead stearate, ammonium sulphate, lithium fluoride etc. are foundto influence the burning rate pressure index n

    Operator algebra quantum homogeneous spaces of universal gauge groups

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    In this paper, we quantize universal gauge groups such as SU(\infty), as well as their homogeneous spaces, in the sigma-C*-algebra setting. More precisely, we propose concise definitions of sigma-C*-quantum groups and sigma-C*-quantum homogeneous spaces and explain these concepts here. At the same time, we put these definitions in the mathematical context of countably compactly generated spaces as well as C*-compact quantum groups and homogeneous spaces. We also study the representable K-theory of these spaces and compute it for the quantum homogeneous spaces associated to the universal gauge group SU(\infty).Comment: 14 pages. Merged with [arXiv:1011.1073
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