For outbreaks of gastrointestinal disease, rapid identification of the source is crucial to enable public health intervention and prevent further cases. Outbreak investigation comprises analyses of exposure information from cases and, if required, undertaking analytical epidemiological studies. Hypothesis generation has been reliant on empirical knowledge of exposures historically associated with a given pathogen. Epidemiology studies are resource-intensive and prone to bias, one of the reasons being the difficulties in recruiting appropriate controls. For this paper, the information from cases was compared against pre-defined background exposure information. As exemplars, three past outbreaks were used, one of common and two of rare exposures. Information from historical case trawling questionnaires was used to define background exposure having removed any exposures implicated with the outbreak. The case-background approach showed good sensitivity and specificity, identifying correctly all outbreak-related exposures. One additional exposure related to a retailer was identified and four food items where all cases had been exposed. In conclusion, the case-background method, a development of the case-case design, can be used to assist with hypothesis generation or when a case-control study may not be possible to carry out.

The Ca II K line serves as an important tool in determining the physics of the photosphere-chromosphere region of the solar atmosphere (Cram 1983). To date detailed analyses have centred on the study of line intensity profiles.

The boreal vegetation of the sub-Arctic comprises more than 30% of the Earth's forest area and plays a major role in controlling the global environment. In the 20th century the boreal vegetation of Fennoscandia was significantly changed by heavy industrialisation leaving many forest areas damaged or dying. Due to severe climate conditions of the sub-Arctic such vegetation changes are traceable over long periods of time. This provides an opportunity to study all types of human impact on vegetation in time and to develop methods to monitor geographical and structural changes in the vegetation cover. Here we present the first part of a larger study in which we use the remote sensing technique to investigate the dynamics of the boreal vegetation in Fennoscandia in context of human impact. We have developed a novel method for an automated analysis and mapping of vegetation and of all types of human impact based on a single support-vector-machines classifier (for the whole area). Implemented with free and open source software the method uses Landsat TM and ETM+ band data (for which it automatically performs atmospheric correction) and a number of indices like NDVI, NBR, etc. The accuracy of the 16-class classification has been assessed using field data and literature sources and determined to be 74.1%. The method has been successfully applied to a study area around Monchegorsk, Kola peninsula, Russia, the most industrialised part of northern Europe. We have characterised all major types of human impact on the boreal forest and tundra vegetation performing the change detection analysis in an area of 1750 km2 between 1986 and 2005. The analysis has confirmed industrial atmospheric pollutions as the primary type of human impact here. We have discussed the role of forest fires and uncovered temporal trends in the vegetation cover. We have found that during the 19 years covered by the study more than one third of all coniferous forest in the area was transformed primarily to wetland, deciduous forest and typical tundra vegetation. The success of the method in this area allows us to extend the study to the rest of Fennoscandia and look at large scale changes in the boreal vegetation cover.

This paper describes a preliminary investigation of the extent to which the normalised difference vegetation index (NDVI), derived from satellite optical imagery, can indicate the extent of damage to upland tundra (fruticose lichen and dwarf shrub) vegetation. We combine the results of a previously reported classification of Landsat multispectral scanner imagery from Kol'skiy Poluostrov, Russia, with field measurements of the biomass and spectral reflectance of tundra vegetation. The results show that the NDVI is not strongly influenced by biomass, but that differences in species composition and ground cover are significant. Other workers have concluded that vegetation indices are not useful for boreal forests. It is therefore suggested that the use of the NDVI by itself as an indicator of the state of disturbed vegetation in Arctic regions is not recommended.

The effects of the insect hormones, ecdysone and 20-hydroxyecdysone, certain non-steroidal ecdysteroid agonists (RH compounds) and the inhibitor, azadirachtin, on the timing of the 3rd-stage moult of Dirofilaria immitis were investigated. 20-Hydroxyecdysone and RH 5849 when used at a concentration of 10−5 M, resulted in a premature timing of this moult. Azadiracthin, at a similar concentration, prevented moulting of most of the larvae to the 4th stage. The results are discussed in relation to the possibility of a hormonal role for ecdysteroids and neuropeptide-like compounds in the control of ecdysis in filarial nematodes, that maybe somewhat comparable to the system which is found in insects.

A series of compounds that apparently disrupt hormonally regulated processes in insects have been examined for effects on the viability and microfilarial production of adult Brugia pahangi cultured in vitro. The azasteroids, 25-azacoprostane and 25-azacholestane, inhibited the production of microfilariae at 5 ppm, the former also exhibiting macrofilaricidal activity at this concentration. The brassinosteroids examined inhibited microfilarial production at 5 ppm but did not affect worm viability. Azadirachtin also proved to be a significant inhibitor of microfilarial release without effect on worm motility or viability. Of all the compounds tested, the non-steroidal amines appeared to be the most promising as potential filaricides, several of them proving to be macrofilaricidal at 1 ppm and affecting microfilarial production at even lower concentrations.

Infective 3rd-stage larvae of three species of marine ascaridoid nematodes, Pseudoterranova (= Phocanema = Porrocaecum = Terranova) decipiens, Anisakis simplex and Phocascaris/Contracaecum sp. were cultured in vitro in 0·9% saline or Medium 199 at 37°C beneath an atmosphere of either air or 95% air:5% CO2 All three species responded to culture at 37°C by producing a new cuticle. The majority of P. decipiens completed ecdysis under all the culture conditions employed. Ecdysis in A. simplex was stimulated by a high concentration of CO2; this effect was particularly noticeable in saline cultures. Both A. simplex and Phocascaris/Contracaecum sp. developed more effectively in a nutrient medium than in saline.

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Although the clinical benefits of dietary supplementation with n-3 polyunsaturated fatty acids (PUFA) has been recognised for a number of years, the molecular mechanisms by which particular PUFA affect metabolism of cells within the synovial joint tissues are not understood. This study set out to investigate how n-3 PUFA and other classes of fatty acids affect both degradative and inflammatory aspects of metabolism of articular cartilage chondrocytes using an in vitro model of cartilage degradation. Using well-established culture models, cartilage explants from normal bovine and human osteoarthritic cartilage were supplemented with either n-3 or n-6 PUFA, and cultures were subsequently treated with interleukin 1 to initiate catabolic processes that mimic cartilage degradation in arthritis. Results show that supplementation specifically with n-3 PUFA, but not n-6 PUFA, causes a decrease in both degradative and inflammatory aspects of chondrocyte metabolism, whilst having no effect on the normal tissue homeostasis. Collectively, our data provide evidence supporting dietary supplementation of n-3 PUFA, which in turn may have a beneficial effect of slowing and reducing inflammation in the pathogenesis of degenerative joint diseases in man.

The main purpose is to characterise continuous maps that are n-branched coverings in terms of induced maps on the rings of functions. The special properties of Frobenius n-homomorphisms between two function spaces that correspond to n-branched coverings are determined completely. Several equivalent definitions of a Frobenius n-homomorphism are compared and some of their properties are proved. An axiomatic treatment of n-transfers is given in general and properties of n-branched coverings are studied and compared with those of regular coverings.