Fitzpatrick M.C.,0 College Street |
Hampson K.,University of Glasgow |
Cleaveland S.,University of Glasgow |
Mzimbiri I.,PO Box 395 |
And 5 more authors.
Annals of Internal Medicine | Year: 2014
Background: The annual mortality rate of human rabies in rural Africa is 3.6 deaths per 100 000 persons. Rabies can be prevented with prompt postexposure prophylaxis, but this is costly and often inaccessible in rural Africa. Because 99% of human exposures occur through rabid dogs, canine vaccination also prevents transmission of rabies to humans. Objective: To evaluate the cost-effectiveness of rabies control through annual canine vaccination campaigns in rural sub-Saharan Africa. Design: We model transmission dynamics in dogs and wildlife and assess empirical uncertainty in the biological variables to make probability-based evaluations of cost-effectiveness. Data Sources: Epidemiologic variables from a contact-tracing study and literature and cost data from ongoing vaccination campaigns. Target Population: Two districts of rural Tanzania: Ngorongoro and Serengeti. Time Horizon: 10 years. Perspective: Health policymaker. Intervention: Vaccination coverage ranging from 0% to 95% in increments of 5%. Outcome Measures: Life-years for health outcomes and 2010 U.S. dollars for economic outcomes. Results of Base-Case Analysis: Annual canine vaccination campaigns were very cost-effective in both districts compared with no canine vaccination. In Serengeti, annual campaigns with as much as 70% coverage were cost-saving. Results of Sensitivity Analysis: Across a wide range of variable assumptions and levels of societal willingness to pay for life-years, the optimal vaccination coverage for Serengeti was 70%. In Ngorongoro, although optimal coverage depended on willingness to pay, vaccination campaigns were always cost-effective and lifesaving and therefore preferred. Limitation: Canine vaccination was very cost-effective in both districts, but there was greater uncertainty about the optimal coverage in Ngorongoro. Conclusion: Annual canine rabies vaccination campaigns conferred extraordinary value and dramatically reduced the health burden of rabies. Primary Funding Source: National Institutes of Health. © Copyright 2014 American College of Physicians. All Rights Reserved.
Nicolle D.,Currency Creek Arboretum |
Kleinig D.A.,P.O. Box 395
Austrobaileya | Year: 2011
The new subspecies Eucalyptus melanophloia subsp. nana is described. The subspecies is of widespread but very scattered distribution in arid regions on rocky sites from the Yaripilangu Range in the Northern Territory in the west (about 250 km WNW of Alice Springs), eastwards to the Mount Isa area in north western Queensland. It is distinguished from subsp. melanophloia by its consistently multi-stemmed, bushy mallee habit and this is unique among the ironbark eucalypts (Eucalyptus series Siderophloiae and E. series Rhodoxylon). Illustrations of the new subspecies (including the holotype), a key to the subspecies of Eucalyptus melanophloia and a distribution map are provided.
De Beer M.,PO Box 395 |
Maina J.W.,PO Box 395 |
Netterberg F.,79 Charles Jackson Street
Journal of the South African Institution of Civil Engineering | Year: 2012
This paper (Part 2 of a two-part set of papers) discusses models and illustrates the adverse effects of weak layers, interlayers, laminations and/or weak interfaces in flexible and semi-flexible pavements, also incorporating lightly cemented layers. The modelling is based on mechanistic analyses for pavement design and evaluation. In Part 1, the effects of these relatively weak layers, interlayers, laminations and/or weak interfaces were discussed. It was shown that methodologies are available to detect and investigate the existence of these weak layers in cemented pavement layers. In Part 2, several cases of the above conditions for different road pavement types are discussed, with field examples. Mechanistic analyses were done on a typical hot mix asphalt (HMA), several cases of a cemented base pavement and a granular base pavement, with and without these weak layers and interface conditions to demonstrate their adverse effects. The analyses focus on the strain energy of distortion (SED) as a pavement response parameter to indicate the potential for structural damage expected within the pavement structure or layer. Generally, the higher the SED, the higher the potential damage in the pavement layer. SED shows some potential for quantifying the relative effects of these weak layers, interlayers, laminations and/or weak interfaces within flexible and semi-flexible pavements.
Netterberg F.,79 Charles Jackson Street |
De Beer M.,PO Box 395
Journal of the South African Institution of Civil Engineering | Year: 2012
Weak layers, interlayers, laminations and/or interfaces in the upper structural layers of road pavements are specifically prohibited in most road-building specifications. However, such layers are extremely common and often lead to premature pavement distress. In Part 1 of this two-part set of papers, it is shown that from experience with heavy vehicle simulator (HVS) and dynamic cone penetrometer (DCP) testing, the presence of such layers and/or conditions at any depth in the structural layers of a flexible or semi-flexible pavement is far more deleterious than is commonly appreciated. In Part 2 the effects of these weak layers are further modelled and discussed using various examples based an HVS testing and mechanistic pavement analyses. In particular, a weak upper base course of a cemented pavement under a thin bituminous surfacing may lead to severe surfacing (and upper base) failure within a matter of weeks to months after opening to traffic, not excluding failure even during construction. In this paper (Part 1), the causes of weak layers, interlayers, laminations and/or interfaces, together with simple methods for their detection during construction and analyses of their effects on the structural capacity of flexible and semi-rigid (cemented) road pavements, are briefly discussed.
Candy L.P.,PO Box 395 |
Lasenby J.,University of Cambridge
IEEE Transactions on Aerospace and Electronic Systems | Year: 2010
The orientation vector differential equation was first derived by John Bortz to improve the accuracy of strapdown inertial navigation attitude algorithms. These algorithms previously relied on the direct integration of the direction cosine matrix differential equation. A compact derivation of the Bortz equation using geometric algebra is presented. Aside from being as simple and direct as any derivation in the literature, this derivation is also entirely general in that it yields a form of the Bortz equation that is applicable in any dimension, not just the conventional 3D case. The derivation presented has the further advantage that it does not rely on multiple methods of representing rotations and is expressed in a single algebraic framework. In addition to the new derivation, the validity of the notion that it is the effect of the noncommutativity of finite rotations that necessitates the use of such an equation in strapdown inertial navigation systems (SDINS) is questioned, and alternative justification for using the Bortz equation is argued. © 2010 IEEE.
Duncker L.C.,PO Box 395
36th WEDC International Conference: Delivering Water, Sanitation and Hygiene Services in an Uncertain Environment | Year: 2013
Limited understanding of the characteristics of different sanitation technology options may affect acceptance of certain technologies in certain circumstances, as well as lead to little appreciation by the users of the long-term financial, environmental and institutional implications of operating and maintaining the various sanitation systems. In South Africa, this has resulted in disturbing increases in the numbers of poorly operated and maintained sanitation technologies across South Africa. The need to establish a facility where people could acquaint themselves with the various sanitation systems was recognised by the CSIR and WRC who made funding available for the establishment of the Sanitation Technology Demonstration Centre at the CSIR. This Centre is aimed at informing local, provincial and national authority officials, NGO's, CBO's, consultants, schools, universities, and importantly, communities themselves in order for them to make informed and educated decisions and choices regarding sanitation technologies.