The performance concept and jointing products – 2

In our previous issue the author discussed the factors which must be taken into account in formulating performance-based test methods for jointing products. Here he develops the theme by examining two proposed test methods for evaluating sealants used in building joints, and relates them to the performance criteria already considered.     

An educational tool to illustrate cost-effectiveness in diagnostic pathways for coronary artery disease

Rapid increases in healthcare costs have led to increased interest in the cost-effectiveness of medical interventions. Coronary artery disease is responsible for a significant share of total healthcare spending, and therefore economic evaluations of medical procedures to treat the condition are potentially very important. We have developed a spreadsheet model as an educational tool that can be used to illustrate cost-effectiveness in the selection of diagnostic pathways (a "work-up" strategy of tests designed to reach a final diagnosis) for coronary artery disease. The model, in Microsoft Excel, is easy to use, requiring no specialist computer knowledge. It is menu-driven and the user navigates the model via a number of on-screen buttons. A data entry screen allows the user to customize the data for the key model parameters, making it possible to take into account location-specific features. The data entry screen also allows the user to undertake sensitivity analysis and rate "what if" scenarios. The model demonstrates how sensitive the cost-effectiveness of different diagnostic pathways is to the pretest probability of disease. This package could also be used as a decision support tool, although it is important to recognize some of its limitations for this purpose.     

Test methods for the movement capability of building sealants. The “state of the art”

The ability of a joint sealant to withstand the diurnal and seasonal cyclic movements imposed by variations of temperature, and in some cases of moisture content, of the adjoining claddings on buildings, without loss of adhesion to joint surfaces or other failures, is of primary importance for its long-term performance. This paper reviews the laboratory test methods which have, been developed to assess this property, from national and international standards. Some simpler test methods for assessing the ability of sealants to withstand maintained extension are also briefly discussed. A number of test apparatuses are described which subject sealants samples simultaneously to cyclic movements and to weather and thus simulate the likely effects of service conditions more closely than is yet possible in laboratory tests. An attempt is made to evaluate the “State of the Art” of assessing the movement capability of building joint sealants, and recommendations made for future work in this field.     

Impact of breakfast consumption on nutritional adequacy of the diets of young adults in Bogalusa, Louisiana: ethnic and gender contrasts

OBJECTIVE: To evaluate the impact of breakfast consumption patterns on the nutritional adequacy of diets of young adults and determine possible ethnic and gender differences. DESIGN AND SETTING: Cross-sectional survey of young adults in Bogalusa, La. SUBJECTS: Twenty-four-hour dietary recalls were collected from October 1988 through October 1991 on 504 young adults (mean age=23 years, 58% women, 70% white). STATISTICS: Analysis of variance and logistic regression techniques were used to investigate the relationship of breakfast consumption, ethnicity, and gender on dietary adequacy. The P values are from an analysis of variance model that adjusted for gender and ethnicity. RESULTS: Thirty-seven percent of young adults skipped breakfast. Of those who ate breakfast, 75% ate at home, 10% ate a fast-food breakfast, and 15% reported other sources. Mean energy intake from breakfast was 485 kcal; men consumed more energy than women (P<.001), and blacks consumed more energy than whites (P<.01). The breakfast meal provided an average of 13% of energy from protein, 55% from carbohydrate, 14% from sucrose, 34% from fat, and 12% from saturated fat. Whites consumed a breakfast higher in carbohydrate and sucrose than blacks, who consumed a breakfast higher in fat and saturated fat. Variations in breakfast foods consumed explained the racial differences in the nutrient composition of the breakfast meal. Young adults who skipped breakfast had lower total daily intakes of energy (P<.0001), protein per 1,000 kcal (P<.05), and saturated fat per 1,000 kcal (P<.01) than those who consumed breakfast. For all vitamins and minerals studied, a higher percentage of young adults who skipped breakfast did not meet two thirds of the Recommended Dietary Allowance than those who consumed a breakfast. APPLICATIONS: Encouraging consumption of breakfast, along with selection of more healthful breakfast food choices or snacks that are culturally appropriate, may be important strategies for improving the nutritional quality of young adults' diets.     

Energy use in bread baking

A study was made of the energy used in production of standard, white, sliced bread in three UK bakeries. The production chain studied covered all stages from receipt of flour at the bakery to arrival of bread at the retail outlet: primary energy use from all sources averaged 6.99 MJ kg-1 bread. In the complete production system for standard bread, including wheat growing, flour milling, baking and retailing, primary energy consumption was 14.8 MJ kg-1 bread and the energy subsidy (primary energy input: food energy output) for the system was 1.49. Primary energy used in home baking was dependent on the degree of loading of the oven and varied from 4.24–16.05 MJ kg-1 bread baked in a gas oven and from 10.84–54.76 MJ kg-1 bread baked in an electric oven. In comparison with mashed potato, roast beef and reheated canned corn, standard bread showed the lowest energy subsidy by a factor of at least five. The energy subsidy for standard bread production was only one-seventh of the figure which applies to the food system as a whole. The findings suggest that bread is the most energy efficient staple food product of an industrialised food production system.     

Object databases as generalizations of relational databases

One attractive approach to object databases is to see them as potentially an evolutionary development from relational databases. This paper concentrates on substantiating the technical basis for this claim, and illustrates it in some detail with an upwards-compatible extension of ANSI SQL2 for conventional objects. This could serve as a foundation for the development of higher-level facilities for more complex objects.     

Atomic force microscopy imaging of fragments from the Martian meteorite ALH84001

A combination of scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) techniques, as well as atomic force microscopy (AFM) methods has been used to study fragments of the Martian meteorite ALH84001. Images of the same areas on the meteorite were obtained prior to and following gold/palladium coating by mapping the surface of the fragment using ESEM coupled with energy-dispersive X-ray analysis. Viewing of the fragments demonstrated the presence of structures, previously described as nanofossils by McKay et al . (Search for past life on Mars — possible relic biogenic activity in martian meteorite ALH84001. Science , 1996, pp. 924–930) of NASA who used SEM imaging of gold-coated meteorite samples. Careful imaging of the fragments revealed that the observed structures were not an artefact introduced by the coating procedure.