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Comparing the mechanical properties of copper castings that had been in service for over 10 years as cooling plates in a blast furnace showed that operational service conditions appear to have no effect on the mechanical properties of the cast copper. Any differences measured between newly cast and ex-service cast coppers can be attributed to differences in grain size in the castings.

Altres ajuts: Biotechnology and Biological Sciences Research Council BB/F017502/1 i Seventh Framework Programme 261504 Some Palaearctic biting midge species (subgenus Avaritia) have been implicated as vectors of bluetongue virus in northern Europe. Separation of two species (C. obsoletus and C. scoticus) is considered difficult morphologically and, often, these female specimens are grouped in entomological studies. However, species-specific identification is desirable to understand their life history characteristics, assess their roles in disease transmission or measure their abundance during arboviral outbreaks. This study aims to investigate whether morphometric identification techniques can be applied to female C. obsoletus and C. scoticus individuals trapped at different geographical regions and time periods during the vector season. C. obsoletus and C. scoticus were collected using light-suction traps from the UK, France and Spain, with two geographical locations sampled per country. A total of 759 C. obsoletus / C. scoticus individuals were identified using a molecular assay based on the cytochrome c oxidase subunit I gene. Fifteen morphometric measurements were taken from the head, wings and abdomen of slide-mounted specimens, and ratios calculated between these measurements. Multivariate analyses explored whether a combination of morphometric variables could lead to accurate species identification. Finally, Culicoides spp. collected in France at the start, middle and end of the adult vector season were compared, to determine whether seasonal variation exists in any of the morphometric measurements. The principal component analyses revealed that abdominal characteristics: length and width of the smaller and larger spermathecae, and the length of the chitinous plates and width between them, are the most reliable morphometric characteristics to differentiate between the species. Seasonal variation in the size of each species was observed for head and wing measurements, but not abdominal measurements. Geographical variation in the size of Culicoides spp. was also observed and is likely to be related to temperature at the trapping sites, with smaller individuals trapped at more southern latitudes. Our results suggest that female C. obsoletus and C. scoticus individuals can be separated under a stereomicroscope using abdominal measurements. Although we show the length and width of the spermathecae can be used to differentiate between the species, this can be time-consuming, so we recommend undertaking this using standardized subsampling of catches. The online version of this article (doi:10.1186/s13071-016-1520-7) contains supplementary material, which is available to authorized users.

Background: Some Palaearctic biting midge species (subgenus Avaritia) have been implicated as vectors of bluetongue virus in northern Europe. Separation of two species (C. obsoletus and C. scoticus) is considered difficult morphologically and, often, these female specimens are grouped in entomological studies. However, species-specific identification is desirable to understand their life history characteristics, assess their roles in disease transmission or measure their abundance during arboviral outbreaks. This study aims to investigate whether morphometric identification techniques can be applied to female C. obsoletus and C. scoticus individuals trapped at different geographical regions and time periods during the vector season. Methods: C. obsoletus and C. scoticus were collected using light-suction traps from the UK, France and Spain, with two geographical locations sampled per country. A total of 759 C. obsoletus/C. scoticus individuals were identified using a molecular assay based on the cytochrome c oxidase subunit I gene. Fifteen morphometric measurements were taken from the head, wings and abdomen of slide-mounted specimens, and ratios calculated between these measurements. Multivariate analyses explored whether a combination of morphometric variables could lead to accurate species identification. Finally, Culicoides spp. collected in France at the start, middle and end of the adult vector season were compared, to determine whether seasonal variation exists in any of the morphometric measurements. Results: The principal component analyses revealed that abdominal characteristics: length and width of the smaller and larger spermathecae, and the length of the chitinous plates and width between them, are the most reliable morphometric characteristics to differentiate between the species. Seasonal variation in the size of each species was observed for head and wing measurements, but not abdominal measurements. Geographical variation in the size of Culicoides spp. was also observed and is likely to be related to temperature at the trapping sites, with smaller individuals trapped at more southern latitudes. Conclusions: Our results suggest that female C. obsoletus and C. scoticus individuals can be separated under a stereomicroscope using abdominal measurements. Although we show the length and width of the spermathecae can be used to differentiate between the species, this can be time-consuming, so we recommend undertaking this using standardized subsampling of catches.

Recent epizootics of Culicoides-borne disease in the Mediterranean Basin have stimulated the development of climate-driven models for vectors. Predictor variables come from two main sources, weather data and satellites. Generally, models for Culicoides imicola combine temperature and moisture variables. The best weather models explain 75-85% of the variance in observed data for C. imicola, but satellite models perform better (85-95% of variance). Predictions of models for other regions appear mixed, with successes and failures. The failures indicate the need to: explore and incorporate other factors that may affect Culicoides populations, such as soil characteristics, host type and wind speed. Develop more complex models, recognising that different climate variables affect different stages of the life-cycle e.g. biological models. The very rapid spread in the distribution of C. imicola in recent years suggests that global warming may be a less important driver of change than other, currently unknown, factors.