Activity function for DCT coded images

By combining a measure of activity in transform-coded image blocks with frequency sensitivity data, suitable psychovisual coefficient quantisation step sizes can be calculated. A number of possible definitions for an activity function A/sub F/ are proposed. The most suitable of these is determined by comparing results on a subjective basis.<>     

The availability to pasture plants of native and applied soil cobalt in relation to extractable soil cobalt and other soil properties

In pot trials using a range of soils from South-East Scotland, plant cobalt concentrations were significantly correlated with the amounts of cobalt extracted from soil with 0.05 M calcium chloride. Plant cobalt concentrations were also correlated with soil pH, showing a decrease with increasing soil pH. There were no significant correlations between plant cobalt concentrations and 0.5 M acetic acid-extractable cobalt, 0.04 M EDTA-exttactable cobalt, isotopically exchangeable cobalt or total soil cobalt. Uptake of cobalt by ryegrass from cobalt added to the soil was inversely related to both the ability of the soil to sorb cobalt and to soil pH.     

Influence of conceptus number and weight on the amount of foetal fluid in the mouse

The relation of extra-embryonic fluid weight to litter number and foetal and placental weight was studied in mice on the 18th day of pregnancy, in litters both of experimentally reduced and of normal number. Partial regression analysis showed that litter number and foetal weight both exerted a negative effect on fluid weight; placental weight had no significant effect. Increased foetal weight reduced weight locally; on the other hand the effect of litter number was exerted systemically, throughout both horns of the uterus.     

The role of T cells in vaccine immunity in the murine model of schistosomiasis mansoni

Naive CBA/Ca mice and mice vaccinated with gamma-irradiated cercariae of Schistosoma mansoni were challenged percutaneously with normal cercariae and depleted of L3T4+ T helper cells through the administration of a specific monoclonal antibody. Three regimes were utilized to target known phases of parasite migration. The in vivo depletion of L3T4+ cells resulted in a significant reduction in immunity (up to 65%) in vaccinated/challenged mice, provided the monoclonal antibody was targeted towards skin-resident schistosomula. When antibody was targeted towards lung phase challenge larvae, however, there was a significant reduction in worm recovery, but no correspondingly significant reduction in vaccine immunity. In contrast, the administration of monoclonal to naive mice, via all three treatment regimes, had no effect on the primary schistosome worm burden. Histopathological studies complemented these worm recovery data. Skin tissue biopsied from vaccinated/challenged mice treated with monoclonal to L3T4+ T cells rarely showed the inflammatory foci which normally characterize untreated vaccinated/challenged mice. This was true when antibody was given either before challenge, or just after challenge, and correlated with the recorded depression in vaccine immunity. Lung tissue collected from monoclonal-treated vaccinated/challenged mice (for all three treatment regimes) exhibited no changes in morphology compared to that from untreated vaccinated/challenged mice. This was not altogether surprising since in the NIMR vaccine mouse model, the lungs represent a poor site for challenge attrition and appear normal in morphology with the exception of a few, small inflammatory reactions. When the monoclonal was given to naive/infected mice, there was no change in the morphology of the pulmonary tissue, as compared to corresponding untreated cohorts. Immunohistochemical studies revealed that Thy-1+ cells dominated the subdermal inflammatory foci of vaccinated/challenged mice. Of the T cells identified, the T helper subset was the most common, with T suppressor cells being only weakly represented, and in some cases not at all. The proportion of macrophages (Mac-1+) varied between reactions.     

The effects of laminations on steep fronted surge propagation inlarge AC motor coils

To date, the modeling of machine windings for steep fronted surge propagation has been based on an assumption that the slot walls act as flux barriers at the frequencies of interest (1 to 10 MHz). This assumption led to the use of a line end coil structure embedded in a solid slot core for experiments, and excellent agreement between measured and computed waveforms has been reported by P.G. McLaren et al. (1988). The assumption is valid for a solid slot environment as the magnetic flux cannot penetrate beyond the skin depth, δ, which is on the order of 10^-6 m for the frequencies concerned. However, this is not the case for a laminated slot environment as it can allow magnetic flux penetration deeper into the core that the skin depth, δ. In the present study, the effects of such a flux penetration on steep fronted surge propagation in large AC motor coils are studied. The results obtained demonstrate that the solid slot models cannot accurately replace the actual laminated environments in the study of steep fronted surge propagation in machine windings. Maximum interturn voltages observed for the solid slot model are smaller (by a factor of about 2/3) than those for the laminated slot environment     

Newton's indigo

Many different explanations have been put forward over the last eighty years to account for Newton's inclusion of indigo as one of the seven spectral colors. The most important of these have been critically examined and it is concluded that it was included solely in the hope of developing an analogy with the musical scale.     

A clinico-pathological study of cutaneous leishmaniasis in British troops from Belize

Thirty-four cases of cutaneous leishmaniasis contracted by British soldiers in Belize were studied. Pre- and post-treatment biopsies were taken from all patients. The range of histological appearances is described and the value of histological examination (including Giemsa staining and immunohistochemistry), cytological preparations and microbiological culture in diagnosis and clinical management assessed. Histology and culture were found to be complementary techniques in reaching a positive diagnosis, whilst cytological preparations were of no additional value. Histological examination of post-treatment biopsies merely confirmed the clinical impression of healing or non-healing whilst culture identified viable organisms in apparently healed lesions, which were subsequently re-treated.     

Publications Sponsored by the Colour Measurement Committee—V The Adams—Nickerson Colour-difference Formula*

The Adams uniform-chromaticity-scale diagram, the Adams-Nickerson uniform colour space (ANLAB) and the derived colour-difference formula are described in detail. An example showing the method of calculating colour differences is given.     

Continuous electrophoretic purification of individual analytes from multicomponent mixtures

Individual analytes can be isolated from multicomponent mixtures and collected in the outlet vial by carrying out electrophoretic purification through a capillary column. Desired analytes are allowed to migrate continuously through the column under the electric field while undesired analytes are confined to the inlet vial by application of a hydrodynamic counter pressure. Using pressure ramping and buffer replenishment techniques, 18% of the total amount present in a bulk sample can be purified when the resolution to the adjacent peak is approximately 3. With a higher resolution, the yield could be further improved. Additionally, by periodically introducing fresh buffer into the sample, changes in pH and conductivity can be mediated, allowing higher purity (>or=99.5%) to be preserved in the collected fractions. With an additional reversed cycle of flow counterbalanced capillary electrophoresis, any individual component in a sample mixture can be purified providing it can be separated in an electrophoresis system.