The hammerhead sharks in Ceylon seas (Family Sphyrnidae)

The present study confirmed the previous listing of this species in the tropical seas around Ceylon (Misra 1947, Munro 1955). Photographs of the ventral surface of the head are shown in Fig. 1 and the distinguishing characteristics of the head are noted in the key to the species

The Study of Oxidation of Magnesium(0001).

The oxidation of Mg(0001) was studied using ESDIAD (Electron Stimulated Desorption Ion Angular Distributions), LEED (Low Energy Electron Diffraction) and STM (Scanning Tunneling Microscopy). Disassociated oxygen and two species of oxygen were observed morphologically by STM and were identified as incorporated oxygen (mixed layer) and ionic oxide MgO(111). We observed that the step terraces and the dissociated oxygen are highly mobile and interact easily with the STM tip at room temperature. The true oxide was first observed on a double step pinning site as a protrusion elongated along the step edge. These sites pin the top terrace to the one underneath forming a double step at the pinning site. A form of oxygen (incorporated) characterized by bumps of 1.2 A in height was observed on the plane of terraces. The bumps and protrusions grow in area and height as a function of oxygen exposure. At 12 L oxygen exposure, bumps coalesce to completely cover the surface. By 13 L, LEED show a diffuse 1 x 1 pattern indicating this growth was in registry with the Mg substrate. At larger oxygen exposures, most of the bumps observed are precursors for the formation of protrusions which leads to the thickening of the oxide. ESDIAD indicates that the initial oxygen is subsurface and that the step edges are not involved in the ion desorption. Formation of the oxide surface was complete by 200 L exposure

Culture-dependent versus Culture-independent Methods for Quantifying Sulphate-Reducing Bacteria in Injection and Produced Water from the Greater Ekofisk Area

Master's thesis in Biological ChemistryPlanktonic and sessile bacteria, in particular sulphate-reducing bacteria (SRB), in the petroleum industry can be damaging to top-side facilities, pipelines and reservoirs. Development of microbial influenced corrosion (MIC), loss of production through reservoir souring, generation of H2S gas and degradation of petroleum products, are some of the main concerns, due to the growth of deleterious microorganisms. These problems can be reduced through appropriate bacteriological monitoring and management. This study has compared the culture-dependent most probable number (MPN) method with the culture-independent quantitative PCR (qPCR) method, for quantifying SRB in injection and produced water from the Greater Ekofisk Area. Further, a qPCR protocol for absolute quantification of SRB was developed. In addition, detection of general aerobic bacteria (GAB) was performed using MPN. Injection and produced water samples were taken over a period of 7 months from the offshore installations Eldfisk 2/7B, Eldfisk 2/7E, Ekofisk 2/4VB and Ekofisk 2/4J. The final standard curve used for quantification was developed with plasmid DNA containing the PCR insert of the dissimilatory sulphite reductase B (dsrB) gene from produced water. SRB was detected by qPCR using dsrB specific primers and the limit of detection (LOD) was 10^3 dsrB copies/µl. qPCR quantified SRB in both injection (10^5-10^6 copies/µl) and produced water (10^7-10^8 copies/µl). SRB was not detected by MPN, whereas GAB was detected in both injection and produced water. Results in this study documents that qPCR is more suitable for detection and quantification of SRB compared to the MPN method and could be beneficial for application at Ekofisk. With the developed qPCR assay, quantitative and objective bacteriological results at Ekofisk can be obtained within a few hours, rather than 30 days as with the MPN method currently applied. Injection water from Ekofisk 2/4VB indicates higher bacterial numbers, and measures should be taken to reduce the microbial flora, to further prevent MIC. Except for Ekofisk 2/4VB, other sampling locations for injection water did not show any signs of bacterial growth, indicating a highly efficient injection water treatment system

Environmental sanitation development of an enabling policy and legislative environment

Environmental sanitation development of an enabling policy and legislative environmen

Increase of storage shelf life of locally produced salted/dried fish by redrying and/or packeting

Experiments were undertaken to prolong the storage life of salted/dried fish by re-drying and/or packing. The storage life under normal conditions is 51 days; re-drying the fish at 50°C for 12 hours extends the storage life only by 7 days. However, re-drying and packing gizzard shad (Gonialosa manminna ) in polyethylene maintains the fish in excellent conditions for well over 87 days. The use of air tight bags for storing good quality salted dried fish is recommended

A preliminary study on the keeping quality of locally produced marine and freshwater salted dried fish

Experiments were conducted on the storage life of salted dried fish from both freshwater and marine species. It was found that the storage life of salted dried products from the 2 freshwater species tested (Ompok bimaculatus and Labeo dussumieri) is much longer than that of the 2 marine species (Gonialosa manminna and Chorinemus lysan), i.e., 51 days

Keeping quality of imported dried fish

All imported salted, dried fish samples tested had a salt content below 30% and above 12% and hence met requirements of the proposed standard. Also samples without quality cut tested had a greater salt content than that with quality cut. This indicates that salt contributes to protecting dried fish and hence may be endorsed by sensory evaluation to a certain extent. Samples with quality cut had more moisture than that without quality cut. But all samples with and without quality cut had a moisture content greater than 35% which is the maximum moisture content for such species specified in the standard. Microbiological testing for total counts and Coliform contents too showed that good quality dried fish had counts greater than that specified in the standard. The different species of fish tested had varying lengths of shelf life. But on an average the shelf life of dried fish could be prolonged for about 12 days by re-drying at 45°C for 6 hours, i.e., re-drying at these temperatures without subsequent packing in polythene bags may not be practical for prolonging the storage life of salted/dried fish

Arthrogryposis in charolais cattle a study on gene penetrance

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