[en] Surveys were carried out in the Milford Haven waterway between Lawrenny and West Angle Bay in March 1996 and April 1997 as part of a programme to monitor the impact of the Sea Empress spill on the sea bed macrofauna within the Haven. Samples were taken at eleven locations for macrobenthos, sediment particle size analysis and determination of hydrocarbon content. Additional data was obtained from a larger scale survey of the waterway in October 1996 which included nine of the eleven stations designated for this sampling programme and 'baseline' data was taken from a similar survey carried out in October 1993. The most noticeable feature of the post-spill data is the low abundance and diversity of the amphipod fauna of the water compared with the October 1993 'baseline'. Although this cannot be ascribed with certainty to the Sea Empress oil spill due to the 21/2 year interval during which no monitoring occurred, depletion of the amphipod fauna is a consistent feature of many previous post-spill studies where there was definitive analytical evidence of oil contamination of the sediments. This project has provided a sound basis for monitoring the progress of the macrobenthic fauna of the Haven in the years after the incident. The greatest benefit in such programmes will only be realised in the long term and it is recommended that monitoring should continue. (author)

[en] This report presents the results of the October 1996 Milford Haven Macrobenthic survey which was conducted eight months after the Sea Empress oil spill, and provides a comparison with the macrobenthic survey of three years previously. The primary aim of this study was to assess the effect of the Sea Empress oil spill upon the benthic macrofauna of the Milford Haven Waterway. In order that direct comparison with the 1993 study could be made wherever possible, there has been consistency in the timing and methodologies employed in the field and in the laboratory. Comparison of individual species distributions and densities indicate changes in several species that can be ascribed to minor positional differences in sample location and to natural variability. However, some taxa, notably amongst the Amphipoda, show widespread declines in their distribution and densities. The balance of evidence suggests that these changes are an acute response to the oil spill. (author)

[en] This report presents the results of the October 1996 Milford Haven Macrobenthic survey which was conducted eight months after the Sea Empress oil spill, and provides a comparison with the macrobenthic survey of three years previously. The primary aim of this study was to assess the effect of the Sea Empress oil spill upon the benthic macrofauna of the Milford Haven Waterway. In order that direct comparison with the 1993 study could be made wherever possible, there has been consistency in the timing and methodologies employed in the field and in the laboratory. Comparison of individual species distributions and densities indicate changes in several species that can be ascribed to minor positional differences in sample location and to natural variability. However, some taxa, notably amongst the Amphipoda, show widespread declines in their distribution and densities. The balance of evidence suggests that these changes are an acute response to the oil spill. (author)

[en] The incidence of Clostridium botulinum in fishery products in Britain and the North Sea is very low. The rate of toxin production was determined in various types of packaged fish which were inoculated with 10¹-10⁶ spores of Cl. botulinum type E per 100 g of fish, at temperatures from 5 to 20°C. Radiation pasteurization at 0.3 Mrad resulted' in an extension of the storage life of the fish but had little effect on the rate of toxin production. In fish irradiated at this level it is possible for toxin to develop in about the same time as it becomes organoleptically unacceptable, in some cases before this stage. Whether toxin is produced before the fish becomes unacceptable or not depends on several factors, the most important being level of contamination and storage temperature. The results presented indicate that as the level of contamination and the storage temperature are decreased, the 'safety margin' between fish becoming unacceptable before development of toxin increases. (author)

[en] The properties of the Cl. botulinum resp. its toxin are described with a view to a combined heat and radiation treatment for fish conservation. The method is tested in several laboratories on 10 different fish products. It is found that the spore former Cl. botulinum is a critical factor in this type of preservation which can hardly be overcome although this method has organoleptic advantages over heat pasteurization of fish. At a storage temperatue over 5⁰C, there is a strong increase in toxin; the same applies to fish with a high fat content. Under poor hygienic conditions, the risk is markedly increased. The author recommends strict control measures in the production and distribution of fish, i.e. cooling and salt treatment. (AJ)

[en] Proposals to treat packaged fish with pasteurizing doses of radiation, and the potential health hazards of this process are described. It is proposed to introduce irradiation into an existing processing and distribution chain for retail packs of chilled fish. The Codes of Practice at present in use provide an adequate safeguard against possible health hazards, primarily by the control of temperature, and limit the storage time to about half the potential shelf life of the fish. Irradiation of these products with 0.3 Mrad will result in a considerable extension of storage life whilst maintaining the same high quality of the product. It is concluded that whilst Clostridium botulinum types E, F and non-proteolytic B could be present in the raw material, no particular health hazard exists unless gross malpractice occurs, especially in relation to the temperature of storage. (author)

[en] The paper first discusses the occurrence of Clostridium botulinum in fish and fishery products and their resistance to irradiation, and then considers the different possible irradiation treatments such as radappertization, radurization and combined processes. For Great Britain it is suggested that sea- frozen fish should be thawed, filleted, packaged and irradiated at 0.3 Mrads. This irradiation treatment would give a sufficient extension of the market life. To eliminate the botulism hazard a temperature of less than 5°C for storage and distribution is recommended. (author)

No abstract available

[en] We investigate the radio and γ-ray beaming properties of normal and millisecond pulsars (MSPs) by selecting two samples from the known populations. The first, Sample G, contains pulsars which are detectable in blind searches of γ-ray data from the Fermi Large Area Telescope. The second, Sample R, contains pulsars detectable in blind radio searches which have spin-down luminosities E>10³⁴ erg s^-1. We analyze the fraction of the γ-ray-selected Sample G which have detectable radio pulses and the fraction of the radio-selected Sample R which have detectable γ-ray pulses. Twenty of our 35 Sample G pulsars have already observed radio pulses. This rules out low-altitude polar-cap beaming models if, as is currently believed, γ-ray beams are generated in the outer magnetosphere and are very wide. We further find that, for the highest-E pulsars, the radio and γ-ray beams have comparable beaming factors, i.e., the beams cover similar regions of the sky as the star rotates. For lower-E γ-ray emitting pulsars, the radio beams have about half of the γ-ray sky coverage. These results suggest that, for high-E young and MSPs, the radio emission originates in wide beams from regions high in the pulsar magnetosphere, probably close to the null-charge surface and to the γ-ray emitting regions. Furthermore, it suggests that for these high-E pulsars, as in the γ-ray case, features in the radio profile represent caustics in the emission beam pattern.

[en] Radio timing observations of the high-magnetic-field pulsar PSR J1718-3718 have shown that it suffered a large glitch with Δν_g/ν = (33.25 ± 0.01) x 10^-6 between 2007 September (MJD 54336) and 2009 January (MJD 54855). This is the largest pulsar glitch ever observed. As is common, there was a small increase in braking torque at the time of the glitch but, unlike all other pulsars, the braking torque has continued to increase over the two years since the glitch. Polarization observations show that the mean pulse profile has about 30% linear polarization with a smooth change of position angle through the pulse, and give a rotation measure of -160 ± 22 rad m^-2. There was no detectable change in pulse profile at the time of the glitch. The timing observations also gave an improved dispersion measure of 371.1 ± 1.7 cm^-3 pc.