Photoelectric measurement of blood flow during hemodialysis

Accurate measurements of blood flow rate during hemodialysis are essential for determinations of hemodialyzer performance. Despite the availability of a variety of electronic blood flow meters, use of such instruments for determination of blood flow in hemodialysis has never been satisfactory, a situation caused by such factors as the need to recalibrate frequently, the necessity of incorporating transducers into the dialyzer blood circuit and the effect which variables such as hematocrit may have on the accuracy of determination. Furthermore, such devices are expensive and often require the periodic services of an electronics specialist to maintain them in an operable condition.An alternative technique for measuring flow rate in the extracorporeal blood tubing consists of timing the passage of an injected air bubble between two points in the tubing. Since the advent of maintenance dialysis, the “racetrack and bubble time” technique [1] has been widely used for routine determinations of blood flow rate. Data derived from research studies in which this method of flow determination was employed have been published widely, in spite of the relative inaccuracies of the method

Farm diversification strategies, dietary diversity and farm size: results from a cross-country sample in South and Southeast Asia

South and Southeast Asia host almost half of the world's undernourished people. Food and agricultural systems in these regions are highly dependent on the production and consumption of staple cereals such as rice, maize and wheat. More diverse farming systems can potentially improve rural people's nutrition, while reducing the environmental impact of agriculture. Yet, it remains uncertain whether farm diversification is always the most suitable and viable strategy for all types of smallholder farms. We use generalised linear regression models to analyse the farm diversification strategies of 4772 rural households in Cambodia, India, Lao PDR and Vietnam. Our analysis is twofold and focuses first on drivers of farm diversification, and second, on the impacts of farm diversification and other livelihood strategies on dietary diversity. We find that (1) farm diversification is significantly influenced by environmental and climate variables, including rainfall patterns, as well as household and farm characteristics such as farm size and education level; and (2) farm diversification, market orientation and off-farm income generation are all strategies that can improve household and individual dietary diversity. However, their relative effects resulted influenced by farm size. Specifically, the positive effect of farm diversification on dietary diversity was larger for smaller farms, while it decreased for farms of larger size that may improve their diet more by increasing their engagement in off-farm activities and markets. These findings highlight that characteristics such as farm size can represent substantial determinants in production and consumption decisions, suggesting the importance of understanding and considering the type of farm and the situational context of analysis when targeting interventions for improving smallholder farm livelihoods

The Early Royal Society and Visual Culture

Recent studies have fruitfully examined the intersection between early modern science and visual culture by elucidating the functions of images in shaping and disseminating scientific knowledge. Given its rich archival sources, it is possible to extend this line of research in the case of the Royal Society to an examination of attitudes towards images as artefacts –manufactured objects worth commissioning, collecting and studying. Drawing on existing scholarship and material from the Royal Society Archives, I discuss Fellows’ interests in prints, drawings, varnishes, colorants, images made out of unusual materials, and methods of identifying the painter from a painting. Knowledge of production processes of images was important to members of the Royal Society, not only as connoisseurs and collectors, but also as those interested in a Baconian mastery of material processes, including a “history of trades”. Their antiquarian interests led to discussion of painters’ styles, and they gradually developed a visual memorial to an institution through portraits and other visual records.AH/M001938/1 (AHRC