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In this paper we reconsider the fundamental problem of the centrifugally driven spreading of a thin drop of Newtonian fluid on a uniform solid substrate rotating with constant angular speed when surface-tension and moving-contact-line effects are significant. We discuss analytical solutions to a number of problems in the case of no surface tension and in the asymptotic limit of weak surface tension, as well as numerical solutions in the case of weak but finite surface tension, and compare their predictions for the evolution of the radius of the drop (prior to the onset of instability) with the experimental results of Fraysse & Homsy (1994) and Spaid & Homsy (1997). In particular, we provide a detailed analytical description of the no-surface-tension and weak-surface-tension asymptotic solutions. We demonstrate that, while the asymptotic solutions do indeed capture many of the qualitative features of the experimental results, quantitative agreement for the evolution of the radius of the drop prior to the onset of instability is possible only when weak but finite surface-tension effects are included. Furthermore, we also show that both a fixed- and a specific variable-contact-angle condition (or ‘Tanner law’) are capable of reproducing the experimental results well.

OBJECTIVE: To determine whether a community based coronary heart disease health promotion project, undertaken over four years, was associated with changes in the prevalence in adults of lifestyle risk factors known to affect the development of coronary heart disease, and to estimate whether such an approach was cost effective. DESIGN: Prospective, comparative study of the effects of a health promotion intervention on coronary heart disease lifestyle risk factors, assessed by postal questionnaire sent to a randomly chosen sample, both at baseline and after four years. SUBJECTS: Intervention and control populations of adults aged 18-64 in Rotherham, both from areas with a high incidence of coronary heart disease and similar socioeconomic composition. MAIN OUTCOME MEASURES: Changes in prevalence of lifestyle risk factors between the control and intervention communities from 1991 to 1995. The effect of the intervention on certain lifestyle behaviours was evaluated using multiple logistic regression to model the proportion with a particular behaviour in the study communities as a function of age (18-40 or 41-64 years), sex, the year of observation (1991 or 1995), and area (intervention of control). RESULTS: 6.9% fewer people smoked and 8.7% more drank low fat milk in the intervention area, but no other statistically significant changes between the areas were detected. The estimated cost per life year gained was pounds 31. CONCLUSIONS: It is possible to have a cost effective impact on coronary heart disease lifestyle risk factors in a population of adults over four years using only modest resources.

OBJECTIVE: To compare prescribing patterns in general practices before and after the introduction of fundholding in April 1993 to determine whether fundholding changed prescribing patterns among practices that joined the scheme. DESIGN: Analysis of prescribing data from the Drug Utilisation Research Unit's database for all practices in Northern Ireland during April 1989 to March 1996. SETTING: Northern Ireland. SUBJECTS: 23-first wave fundholders, 34 second wave fundholders, 9 third wave fundholders, and 268 non-fundholders. MAIN OUTCOME MEASURES: Prescribing costs per 1000 patients, prescription items per 1000 patients, average cost per item, and rate of generic prescribing. RESULTS: Prescribing costs and frequency increased in all groups throughout the study. Among the fundholders the rate of increase in costs after fundholding was significantly lower than among non-fundholders. The rate of increase in cost per item fell, coinciding with a significant increase in the rate of generic prescribing. However, with regard to first wave fundholders, their yearly increase in costs in their third year as fundholders (1995-6) was similar to that of the non-fundholders. The earlier practices that joined the scheme seemed to differ in some important respects from those that joined later. CONCLUSIONS: After fundholders joined the fundholding scheme their patterns of prescribing changed compared with those of non-fundholders: the rate of increase in costs fell and there was a significant rise in the rate of generic prescribing.

OBJECTIVE: To determine the strength of association between history of blood transfusion and development of Creutzfeldt-Jakob disease. DATA SOURCES: English and non-English language articles published from January 1966 to January 1999 were retrieved using a keyword search of Medline and Embase. These were supplemented by handsearching key journals and searching bibliographies of reviews. STUDY SELECTION: Two independent reviewers selected the relevant abstracts and articles. Articles were chosen that reported the results of case-control studies trying to identify rates of prior blood transfusion in patients with Creutzfeldt-Jakob disease and in controls. DATA EXTRACTION: Odds ratios and information on study quality were extracted from the selected articles by two independent reviewers. DATA SYNTHESIS: Five studies containing data on 2479 patients were included. Three of the five studies used medical or neurological patients as controls, the other two used population controls. Odds ratios for developing Creutzfeldt-Jakob disease from blood transfusion ranged from 0.54 to 0.89. Four of the five studies had confidence intervals that crossed 1.0. The combined odds ratio was 0.70 (95% confidence interval 0.54 to 0.89). CONCLUSIONS: Case-control studies do not suggest a risk of developing Creutzfeldt-Jakob disease from blood transfusion. Rather, a trend seems to exist towards a lower frequency of previous blood transfusion in patients with Creutzfeldt-Jakob disease than in controls. However, it is important to be aware of these studies' methodological limitations-primarily the choice of control population and reliability of recall of transfusion status.

A thermal modulator that can act as an interface between supercritical fluid extraction and supercritical fluid chromatography is developed and tested. The modulator is made of a short segment of a fused silica capillary column, coated on the outside with electrically conductive paint so that it can be heated rapidly by a pulse of electric current. An equivalent of an injection is made internally within a flowing stream containing the sample by alternately heating and cooling the modulator, rather than by introduction through an injection port or a valve.

New conductor pastes have made possible great improvements in the loss characteristics of thick film microwave integrated circuits. This paper presents data on the microwave characteristics of transmission structures made from newly developed copper, silver and gold conductor pastes on alumina and garnet substrates. The resistivity and microstructure for each conductor material was examined for correlation with microwave properties. These data show that thick film circuits can give excellent performance through 18 GHz.

DURING the course of an experiment in the use of copper sulphate against bilharzia snail hosts in the season 1951–52, it was noted that the water-weed vegetation appeared to be affected by the treatment.

MUCH is written upon the subject of soil exhaustion in Africa, and it seems to be generally accepted that the soils of the tropics require careful management, including frequent periods of rest, if fertility is to be maintained. In the great clay plains of the Sudan1in particular, it has been emphatically stated that uncontrolled continuous cultivation of land around water points and villages is responsible for the poor crops and general poverty of the villagers, and that only the provision of new villages at new water points, where cultivation can be rigidly controlled, can solve the problem. It cannot be doubted that soil erosion is responsible for reduction of yields in some cases. The question then arises, what is the reason for the very markedly poor yields of the grain and fodder crop, Sorghum vulgare, Pers., on the village cultivations, where soil erosion is not marked? The answer in the northern and central Sudan seems to be the root parasite Striga hermontheca, Benth., which is prevalent in more or less degree wherever this crop is grown, being indigenous as a parasite of the native grasses. By suitable treatment with hormone weedkillers2it has been shown that it is possible to kill much of the Striga and bring about very considerable increases in yield on irrigated land. During the 1952 season, an experiment was carried out on a piece of village land near Gedaref, in the eastern Sudan, which has been under cultivation for longer than can be remembered by the oldest inhabitants. The result was that sorghum on the untreated plots yielded 427 lb. of heads to the acre, whereas that on plots treated against Striga yielded 1,183 lb. of heads to the acre (P better than 5 per cent). This latter would be a fairly good yield for newly opened land.