Has bovine somatotropin (BST) an effect upon drug disposition? Comparative studies in goats and cattle with sulphadimidine and antipyrine after parenteral administration of BST,zeranol and proligestone

Daily subcutaneous BST injection in lactating cows, bulls and castrated male dwarf goats did not induce significant changes in the pharmacokinetic parameters of antipyrine (AP) and sulphadimidine (SDD). Similarly, no changes were obtained after injection of slow-release BST formulations in lactating cows and non-lactating female goats. In contrast to androgenic hormones, both zeranol and proligestone had no effect upon the disposition of AP and SDD, although both synthetic hormones did induce enhanced plasma somatotropin concentrations. In goats, metabolic effects induced by zeranol and BST included significant reductions in plasma urea values, whereas plasma creatinine levels were somewhat lower after daily BST administration.     

Solar ultraviolet radiation as a causal factor of 'summer syndrome' in cage-reared Atlantic salmon, Salmo solar L.: a clinical and histopathological study

Abstract. During the exceptionally good summer of 1984, severe losses occurred at a number of marine salmon farms in the west of Ireland. Clinical signs and associated histopathology of the disease are described together with relevant meteorological data gathered during the course of the mortalities. The clinical, histopathological and meteorological data observed strongly suggest that prolonged exposure to solar ultraviolet radiation played a major role in the losses which occurred. Other contributory factors involved in the mortalities are described and discussed.     

The influence of ultraviolet-B radiation on the mechanism of wound repair in the skin of the Atlantic salmon, Salmo salar L.

Abstract. Exposure of surgically damaged skin of Atlantic salmon, Salmo salar L., to low levels of ultraviolet-B radiation in clear water showed that the basic mechanism of superficial wound healing, characterized by epidermal migration, was unaffected. However, the migrating cells were more vulnerable to the necrotizing effects of the irradiation than the surrounding donor epithelium and longer standing effects such as wound contracturc and resolution of epidermal structure failed to occur.     

Self-trapping of dark incoherent light beams

"Dark beams" are nonuniform optical beams that contain either a one-dimensional (1D) dark stripe or a two-dimensional (2D) dark hole resulting from a phase singularity or an amplitude depression in their optical field. Thus far, self-trapped dark beams (dark solitons) have been observed using coherent light only. Here, self-trapped dark incoherent light beams (self-trapped dark incoherent wavepackets) were observed. Both dark stripes and dark holes nested in a broad partially spatially incoherent wavefront were self-trapped to form dark solitons in a host photorefractive medium. These self-trapped 1D and 2D dark beams induced refractive-index changes akin to planar and circular dielectric waveguides. The experiments introduce the possibility of controlling high-power coherent laser beams with low-power incoherent light sources such as light emitting diodes.     

THE EFFECT OF SOIL COMPOSITION AND ENVIRONMENTAL FACTORS ON THE SHRINKAGE OF SOME CLAYEY BRITISH SOILS

The shrinkage potential of natural clods from a variety of clayey soils was measured and related to their physical, chemical and mineralogical properties. It is shown that the most important factors affecting shrinkage are initial bulk density, clay content, organic carbon content and cation exchange capacity of the peroxidised clay, and mica-smectite content on a whole soil basis. Multiple regression equations involving the initial bulk density, clay content, organic carbon and cation exchange capacity accounted for 87 and 82 per cent of the variation in total shrinkage of topsoils and subsoils respectively. Because of restrictions on shrinkage imposed by factors such as climate, crops, ground-water and moisture release characteristics of soils, soils with a high shrinkage potential may not behave very differently to soils with a much lower potential. On these grounds it is concluded that the shrinkage criteria used in US Taxonomy are not applicable in Britain.     

ROTHAMSTED STUDIES OF SOIL STRUCTURE 1.: PURPOSE OF THE PROJECT, SOILS SELECTED, AND GENERAL CONCLUSIONS

The agricultural background, morphology, and classification of soils from the Hans lope, Ragdale, Evesham, Denchworth, Flint and Salop series are presented together with basic analytical measurements of particle size and chemistry and with some details of the field water regimes. This information serves as essential background to other studies of soil structural properties as they relate to management of the same soils.