Parsimonious Catchment and River Flow Modelling

It is increasingly the case that models are being developed as “evolving” products rather than\ud one-off application tools, such that auditable modelling versus ad hoc treatment of models becomes a\ud pivotal issue. Auditable modelling is particularly vital to “parsimonious modelling” aimed at meeting\ud specific modelling requirements. This paper outlines various contributory factors and aims to seed\ud proactively a research topic by inextricably linking value/risk management to parsimonious modelling.\ud Value management in modelling may be implemented in terms of incorporating “enough detail” into a\ud model so that the synergy among the constituent units of the model captures that of the real system. It is a\ud problem of diminishing returns, since further reductions in the constituent units will create an\ud unacceptable difference between the model and the real system; conversely, any further detail will add to\ud the cost of modelling without returning any significant benefit. The paper also defines risk management\ud in relation to modelling. It presents a qualitative framework for value/risk management towards\ud parsimonious modelling by the categorisation of “modelling techniques” in terms of “control volume.

The maximum medical aid price programme: A review of the concept and of its ability to reduce expenditure on medicines

Medicine prices in South Africa have increased significantly in recent years. Furthermore, a consideration of expenditure on medicines by medical schemes shows that this component of health care costs had grown to 26,1% in 1988, which is high by comparison with other Western economies. The use of generic medicines offers one possible solution to rising expenditure. For savings to be optimised, however, generics need to be used on a planned and structured basis. The maximum medical aid price (MMAP) system of the Pharmaceutical Society of South Africa provides such a programme.MMAP is a programme through which certain medical schemes elect to pay only a specified maximum price for offpatent products that have generic equivalents. Although MMAP does not require substitution by generic medicines, it does have the effect of encouraging their use.Two case studies measuring the savings that can be achieved through adoption of MMAP by medical schemes are reviewed. Although they differ in their respective  methodologies, their results are consistent and show that savings of about 9,3% were possible in 1989. Medical schemes with higher proportions of older members tend to show greater savings. The studies also show that the potential for achieving savings through the use of MMAP increases with the passage of time

FM receiver dynamic response

Dynamic response of frequency modulation radio receiver employing amplitude sensitive discriminato

Money and happiness : rank of income, not income, affects life satisfaction

Does money buy happiness, or does happiness come indirectly from the higher rank in society that money brings? Here we test a rank hypothesis, according to which people gain utility from the ranked position of their income within a comparison group. The rank hypothesis contrasts with traditional reference income hypotheses, which suggest utility from income depends on comparison to a social group reference norm. We find that the ranked position of an individual’s income predicts general life satisfaction, while absolute income and reference income have no effect. Furthermore, individuals weight upward comparisons more than downward comparisons. According to the rank hypothesis, income and utility are not directly linked: Increasing an individual’s income will only increase their utility if ranked position also increases and will necessarily reduce the utility of others who will lose rank

Meeting the Changing Need for Herbage Seed Quality Assurance in the 21st Century

Quality assurance is a key element in the herbage seed supply chain. The measurement and management of seed quality is discussed in terms of its four main parameters - genetic, physical, vital, and phytosanitary quality - which provide information on the expected performance of herbage seed when sown in the field. During the past century, seed quality management systems have evolved in response to national and regional differences in economic development, crop characteristics, merit testing, and the demands of international trade. The pace of change in the management of seed quality assurance has intensified in developed countries over the past decade or so, driven mainly by the ability to protect intellectual property, the consolidation of seed companies into larger units, and government policy aimed at deregulating the delivery of quality assurance. In developed countries, this has seen the strong private seed sector taking increasing responsibility for seed quality assurance, both economically and legally, together with the emergence of private seed testing laboratories and in-house certification programs. However, developing countries without a strong private seed sector are better served by the more traditional model in which government takes on the role and responsibility for managing seed quality assurance in the public interest. This paper explores recent trends in seed quality management and their strategic implications for different countries now and in the future with particular reference to herbage seed

Income rank and upward comparisons

Many studies have argued that relative income predicts individual well-being. More recently, it has been suggested that the relative rank of an individual’s income, rather than how that income compares to a mean or reference income, is important. Here the relative rank hypothesis is examined along with the additional hypothesis that individuals compare their incomes predominantly with those of slightly higher earners. A study of over 12,000 British adults using the British Household Panel Survey (a) confirms the importance of rank and (b) finds evidence that individuals compare upwards and to those most similar. This paper appears to be the first to show in fixed effect well-being equations that the influence of rank is more important than the influence of relative pay

Impact craters on Venus: An overview from Magellan observations

Magellan has revealed an ensemble of impact craters on Venus that is unique in many important ways. We have compiled a database describing 842 craters on 89 percent of the planet's surface mapped through orbit 2578 (the craters range in diameter from 1.5 to 280 km). We have studied the distribution, size-frequency, morphology, and geology of these craters both in aggregate and, for some craters, in more detail. We have found the following: (1) the spatial distribution of craters is highly uniform; (2) the size-density distribution of craters with diameters greater than or equal to 35 km is consistent with a 'production' population having a surprisingly young age of about 0.5 Ga (based on the estimated population of Venus-crossing asteroids); (3) the spectrum of crater modification differs greatly from that on other planets--62 percent of all craters are pristine, only 4 percent volcanically embayed, and the remainder affected by tectonism, but none are severely and progressively depleted based on size-density distribution extrapolated from larger craters; (4) large craters have a progression of morphologies generally similar to those on other planets, but small craters are typically irregular or multiple rather than bowl shaped; (5) diffuse radar-bright or -dark features surround some craters, and about 370 similar diffuse 'splotches' with no central crater are observed whose size-density distribution is similar to that of small craters; and (6) other features unique to Venus include radar-bright or -dark parabolic arcs opening westward and extensive outflows originating in crater ejecta

Reproducible Method for Calibrating the Backscattered Electron Signal for Quantitative Assessment of Mineral Content in Bone

Backscattered electron (BSE) imaging shows promise for orthopaedic and bone research. BSE images of bone may be captured on-line directly from the scanning electron microscope (SEM), and then analyzed to produce a backscattered electron profile (BSEP), a modified image graylevel histogram which is representative of the mineral content in bone. The goals of this work were 1) develop a reproducible graylevel calibration technique for bone specimens, and 2) determine a conservative time interval during which SEM operating conditions would remain stable. Calibration standards containing pure aluminum and pure magnesium wires were placed in the SEM with human cancellous bone. Baseline imaging conditions were first established by adjusting the SEM until the bone image displayed good resolution and graylevel separation between regions of different mineral content. Microscope brightness and contrast controls were randomly changed to initiate the new operating conditions of another imaging session, and graylevel values from the calibration metals were used to readjust the microscope back to baseline operating conditions. Weighted mean graylevel values of the BSEPs from calibration trials were compared to those of the baseline. Data showed that bone images could be reproduced within 1.2 percent. It was also concluded that our equipment required calibration checks at 20 minute intervals

Morphological and heartwood variation of Santalum macgregorii in Papua New Guinea

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Santalum macgregorii (sandalwood), which is endemic to the southern part of Papua New Guinea (PNG), has been heavily exploited for its fragrant heartwood and is classified as threatened across its natural range. Domestication and smallholder agroforestry offer the means to preserve remaining diversity. This study was undertaken to understand the extent of remaining natural variation to support the species’s conservation and domestication. We evaluated morphological, heartwood and essential oil characters in 126 S. macgregorii trees in five populations (districts) in PNG’s Central, Gulf and Western provinces. The heartwood oil of this species is characterised by extreme tree-to-tree variation in key fragrant compounds. Proportions of individual compounds range from negligible to high for (Z)-α-santalol (0.5–51%), (Z)-β-santalol (0–24.2%), (Z)-nuciferol (0–40.5%) and (Z)-lanceol (0–72%). Despite the wide variation found within populations, an ordination of seven oil constituents revealed broad provenance-based variation in which trees from the eastern provinces (i.e. Central and Gulf) were more influenced by (Z)-nuciferol content and the trees from the Western Province site were more strongly influenced by (Z)-lanceol. The driver of this variation was the different associations between oil constituents, with (Z)-α- and (Z)-β-santalol both negatively correlated with (Z)-nuciferol for sites in the eastern provinces and (Z)-lanceol in Western Province. No evidence of distinct chemotypes was found, with continuous variation demonstrated across all major oil constituents. Of the trees surveyed with a basal diameter of \u3e 10 cm, 79% had heartwood. Mean heartwood percentage was 15.8% of basal area, with no significant differences between sites. Significant tree-to-tree variation in heartwood percentage (0–61%) was found. A modest positive correlation was found between stem and heartwood diameter (r = 0.39). Heartwood percentage and heartwood oil quality varied independently and, therefore, independent selection of these traits may be required for their simultaneous improvement. The population in Western Province is non-contiguous with those in the eastern part of the species distribution. It also has a distinct phenotype based on oil composition, leaf shape, flower colour and potential reproductive failure. It is possible that sandalwood in Western Province is more closely related to the proximal populations of S. lanceolatum in Cape York Peninsula, Queensland, than the more distant populations of S. macgregorii in PNG. While these phenotypic features do not necessarily discriminate a new species, molecular genetic research is required to determine the potential existence of a cryptic species of sandalwood. The implications of the variation found in S. macgregorii are discussed with respect to its domestication and conservation