1,830 research outputs found

    Investigations on the consumption of sugar by South African populations

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    By means of questionnaires, appropriate for both individuals and households, surveys of sugar intake have been carried out in the Transvaal on groups of South African Whites, Indians, Malays, Coloureds, and Bantu. Inquiries concerned groups in urban and rural areas, and in different socio-economic circumstances. In Whites the consumptions per capita resemble data published in the United Kingdom. Mean intakes, in round figures, range from 80 to 100 g per day for those in the higher socio-economic groups, to 120 - 140 g for those in lower-income groups. For Indians the mean consumptions, 70 - 90 g, are less than the intakes of Whites, and slightly less than the limited data on Coloureds and Malays. The Coloureds and Malays were not extensively investigated; the mean intakes of about 90 g are lower than those of Whites in similar economic circumstances. Among the rural groups of Bantu studied, mean intakes range from 65 to 75 g per day, while in urban areas ranges are greater, 55 - 85 g per day. Miscellaneous findings were that males consume more sugar than females; intake rises with age, but falls off in late middle-age; intake falls with increase in family size; and among Whites, intake tends to decrease with rise in privilege (this change is not yet apparent in non-White groups). In the future, sugar intake will certainly increase in the non-White populations, particularly the Bantu

    Archives of the Congregation of the Mission, Province of the West

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    This inventory of the Province of the West’s archives reflects its holdings at the end of 1988, with some notable additions. Highlights include materials on the Congregation’s government, including minutes, working papers, and other documents for general assemblies; records for each American province (with the greatest emphasis on the Province of the West), reflecting the Congregation’s historical growth in the United States; published works on the Daughters of Charity; various items on the Ladies of Charity and the Saint Vincent de Paul Society; publications (amounting to hundreds of titles) on Vincent de Paul, Louise de Marillac, Catherine Laboure, and Elizabeth Ann Seton; and various audio-visual materials

    Estimation of erosion model erodibility parameters from media properties

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    The aim of this research was to enable erodibility values for hillslope-scale erosion prediction models to be determined from easily measured media properties. Simulated rainfall and overland flow experiments were carried out on 34 soils and overburdens from 15 Queensland open-cut coal mines at The University of Queensland Erosion Processes Laboratory. Properties of the 34 media determined included aggregate stability, Atterberg limits, bulk density, cation exchange capacity, dispersion ratios, electrical conductivity, exchangeable sodium percentage, organic carbon content, pH, texture, and water content at field capacity and wilting point. Correlation and stepwise multiple regression procedures were used to determine those media properties that could best be used to predict rill and interill erodibility. Correlations between media properties and sediment delivery at each of 5, 10, 15, 20, and 30% slope revealed that different media properties were correlated with erosion rates at different slopes. A media property could show a strong correlation with erodibility at 30% slope, and a low correlation at 5% slope. Splitting the data set into soils only, and overburdens only, showed that properties that were positively correlated with erosion rates for one group could be negatively correlated for the other group. Therefore, in this study, erodibility could not be explicitly linked to one set of media properties for all medium types and erosive conditions. It was concluded that a single regression equation could not be used to predict erodibility under all conditions. Instead, 4 equations were developed to predict rill and interill erodibility, for soils and overburdens separately. The need for separate regression equations was attributed to the presence of different erosive sub-processes for specific combinations of medium type and slope gradient

    Use of laboratory-scale rill and interill erodibility measurements for the prediction of hillslope-scale erosion on rehabilitated coal mine soils and overburdens

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    Prediction of hillslope-scale soil erosion traditionally involves extensive data collection from field plots under natural rainfall, or from field rainfall simulation programs. Recognising the high costs and inconvenience associated with field-based studies, a method was developed and tested for predicting hillslope-scale soil erosion from laboratory-scale measurements of erodibility. A laboratory tilting flume and rainfall simulator were used to determine rill and interill erodibility coefficients for 32 soils and overburdens from Queensland open-cut coal mines. Predicted sediment delivery rates based on laboratory determinations of erodibility were tested against field measurements of erosion from 12-m-long plots under simulated rainfall at 100 mm/h on slopes ranging from 5% to 30%. Regression analysis demonstrated a strong relationship between predicted and measured sediment delivery rates, giving an r2 value of up to 0.74, depending on the particular modeling approach used. These results demonstrate that soil losses due to the combined processes of rill and interill erosion at the hillslope scale can successfully be predicted from laboratory-scale measurements of erodibility, provided a suitable methodology and modelling approach is adopted. The success of this approach will greatly reduce the cost and effort required for prediction of hillslope scale soil erosion

    Thinking counterfactually supports children's ability to conduct a controlled test of a hypothesis

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    Children often fail to control variables when conducting tests of hypotheses, yielding confounded evidence. We propose that getting children to think of alternative possibilities through counterfactual prompts may scaffold their ability to control variables, by engaging them in an imagined intervention that is structurally similar to controlled actions in scientific experiments. Findings provide preliminary support for this hypothesis. Seven- to 10-year-olds who were prompted to think counterfactually showed better performance on post-test control of variables tasks than children who were given control prompts. These results inform debates about the contribution of counterfactual reasoning to scientific reasoning, and suggest that counterfactual prompts may be useful in science learning contexts

    Estimated workload intensity during volunteer aquarium dives

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    Background: This study aimed to characterize the physiological demands of working dives on volunteer divers at a public aquarium in the USA. Aims: To estimate the workloads associated with volunteer dives in a US aquarium. Methods: Participants completed a medical and diving history questionnaire. Measurements included blood pressure before and after diving and continuous ECG (Holter) monitoring during diving. Dive profiles were recorded using loggers. Mean workload was estimated from total air consumption. Results Twenty-seven divers recorded 49 air dives over 5 days. Two-thirds were male and ages ranged from 40 to 78 years. Typically, each diver made two dives with a 30-60 min surface interval. Mean heart rate while diving was 100 beats per minute (bpm). Mean estimated workload during the dives recorded during this study was 5.8 metabolic equivalents (METS), with a range from 4.1 to 10.5. The highest mean recorded heart rate was 120 bpm over 40 min, vacuuming the floor in the shark exhibit. Conclusions: Given the mean age of this sample and the prevalence of cardiovascular risk factors (body mass index, high cholesterol and hypertension), it may be prudent for aquariums to regularly monitor SAC/kg and heart rate in volunteer divers, to identify which tasks require the highest workload intensity. Divers with existing cardiovascular risk factors might then be employed in dives with lighter workloads. In conclusion, volunteer dives at this aquarium required a mean workload intensity that was described by recreational divers as moderate. The highest workload, at 10 METS for 23 min, would be considered by many recreational divers as exhausting

    Experimental determination of the dispersion relation of magnetosonic waves

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    Magnetosonic waves are commonly observed in the vicinity of the terrestrial magnetic equator. It has been proposed that within this region they may interact with radiation belt electrons, accelerating some to high energies. These wave-particle interactions depend upon the characteristic properties of the wave mode. Hence, determination of the wave properties is a fundamental part of understanding these interaction processes. Using data collected during the Cluster Inner Magnetosphere Campaign, this paper identifies an occurrence of magnetosonic waves, discusses their generation and propagation properties from a theoretical perspective, and utilizes multispacecraft measurements to experimentally determine their dispersion relation. Their experimental dispersion is found to be in accordance with that based on cold plasma theory

    Ixodes (Afrixodes) bakeri Authur & Cliford, 1961 (Acarina : Ixodidae): description of the male and immature stages from rodents and insectivores and notes on its biology in South Africa

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    The male, nymph and larva of Ixodes (A.) bakeri are described and illustrated with line drawings and scanning electron microscope photographs. This species was originally described from 1 female from Otomys sp., Nyika Plateau, Malawi. The present material consists of 28 collections from insectivores and 19 collections from rodents, Van Riebeeck Nature Reserve, Transvaal, plus 1 collection from a rodent in the Jonkershoek Valley, Cape Province, Republic of South Africa. Its biology in South Africa is also discussed.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format

    Ixodes (Afrixodes) neitzi, n. sp. (Acarina :Ixo didae) from the mountain reedbuck in South Africa

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    Ixodes (Afrixodes) neitzi n. sp. is described from females and males collected from the mountain reedbuck (Redunca fulvorufula) at Loskop Dam Nature Reserve, Transvaal, Republic of South Africa. Information is provided to distinguish this new species from other closely related Ixodes species that occur in the Ethiopian region. Its predilection sites are noted and the area in which it occurs is described briefly.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    Clarification of the status of Rhipicephalus kochi Dönitz, 1905 (Ixodoidea, Ixodidae)

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    Figures of the types of Rhipicephalus kochi, and of its synonym Rhipicephalus neavei Warburton, 1912, are presented. These are accompanied by complete descriptions of all stages of R. kochi, illustrated with scanning electron microscope photographs. The basic differences between this species, Rhipicephalus pravus Dönitz, 1910 and Rhipicephalus punctatus Warburton, 1912 are outlined. R. kochi occurs south of the Equator in parts of eastern, central and southern Africa. Its adults feed most commonly on cattle, various antelopes and wild pigs, and on hares. Little is known about the hosts of the immature stages; nymphae have been recorded in a field collection once only, from Petrodromus tetradactylus, the 4-toed elephant shrew.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
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