Vertical activity estimation using 2D radar

Understanding airspace activity is essential for airspace control. Being able to detect vertical activity in aircraft allows prediction of aircraft intent, thereby allowing more accurate situation awareness and correspondingly more appropriate airspace control response. The method for qualitative vertical activity estimation as presented is characterised by a very fast response time and requires minimal sensor input. The method relies on the interplay of two opposing motion prediction models. The efficacy of the method is demonstrated in both simulated and real-world data. Scientia Militaria: South African Journal of Military Studies Vol. 36 (2) 2008: pp. 60-7

Aircraft Height Estimation using 2-D Radar

A method to infer height information from an aircraft tracked with a single 2-D search radar is presented. The method assumes level flight in the target aircraft and a good estimate of the speed of the aircraft. The method yields good results for medium to high altitudes, though performs weaker at low altitudes. The method can distinguish between high and low targets on a normal 2-D radar, and can reach a height resolution of 100 m provided the 2-D radar is optimised to the task.Defence Science Journal, 2010, 60(1), pp.100-105, DOI:http://dx.doi.org/10.14429/dsj.60.11

Circulating asbestos: The International AC Review, 1956-1985

Hannah le Roux follows the material flows and corporate geographies of asbestos-cement, a construction material that proliferated globally in the twentieth century. As a challenge to architectural history and media, the essay reveals the industrial, academic, professional, and political links between modernity and toxicity: le Roux traces how the Swiss-based multinational Eternit marketed its asbestos product from the 1950s on through the company magazine ac: International asbestos-cement review; how architectural historian Sigfried Giedion placed himself at the service of industry by promoting asbestos-cement in writing for ac review and by using it to build his own home; and how, through the efforts of the United Nations, the material became widespread in the Global South through prefabricated housing. Even after bans in many countries, the lingering presence of asbestos-cement is a form of “slow violence” that suggests the need for a “slower science.

Coffeemanifesto : sampling instant and slow spaces in the African city

In the inner city of Johannesburg, Ethiopian traders and their landlords have occupied and redefined empty modernist buildings, creating a rich and dense urban market area. The fabric of the existing buildings and open spaces allows an arrangement of spaces and functions that support a community in transformation, allowing dynamic changes while also evoking stable images of home in a series of safe and networked social spaces. This rich urbanism is proposed as a positive alternative to its tough surroundings, and to the sterility of developer led urban renewal. The paper describes a process of designerly research in the area, including performative work, that intends to represent and advocate for official recognition of the ambivalent nature of these spaces, and their transformative potentials.Department of Culture, Delegation of the Flemish Government in South Africa, Embassy of Belgiumhttps://africanperspectivesconference.wordpress.com

A Bayesian approach for inferring the dynamics of partially observed endemic infectious diseases from space-time-genetic data

We describe a statistical framework for reconstructing the sequence of transmission events between observed cases of an endemic infectious disease using genetic, temporal and spatial information. Previous approaches to reconstructing transmission trees have assumed all infections in the study area originated from a single introduction and that a large fraction of cases were observed. There are as yet no approaches appropriate for endemic situations in which a disease is already well established in a host population and in which there may be multiple origins of infection, or that can enumerate unobserved infections missing from the sample. Our proposed framework addresses these shortcomings, enabling reconstruction of partially observed transmission trees and estimating the number of cases missing from the sample. Analyses of simulated datasets show the method to be accurate in identifying direct transmissions, while introductions and transmissions via one or more unsampled intermediate cases could be identified at high to moderate levels of case detection. When applied to partial genome sequences of rabies virus sampled from an endemic region of South Africa, our method reveals several distinct transmission cycles with little contact between them, and direct transmission over long distances suggesting significant anthropogenic influence in the movement of infected dogs

Lizard epidermal gland secretions II : chemical characterization of the generation gland secretion of the sungazer, Cordylus giganteus

The original publication is available at http://pubs.acs.org/doi/full/10.1021/np1008366In lizards, the epidermal glands of the femoral and precloacal regions are involved in the production of semiochemicals. In addition to its femoral glands, the giant girdled lizard, or sungazer, Cordylus giganteus, which is endemic to South Africa, has generation glands as an additional potential source of semiochemicals. These epidermal glands are described as glandular scales that overlay the femoral glands and are included in the normal epidermal profile located in the femoral (thigh) and anterior antebrachial (fore-leg) regions of the male sungazer. GC-MS analysis of the generation gland secretions and the trimethylsilyl derivatives of some of the steroidal constituents was employed to identify 59 constituents, including alkenes, carboxylic acids, alcohols, ketones, aldehydes, esters, amides, nitriles, and steroids. The quantitative differences of the volatile constituents of the fore- and hind-leg generation glands were compared between individuals. This is the first report on the chemical composition of generation glandular material of lizards. © 2011 The American Chemical Society and American Society of Pharmacognosy.Post-prin

Cytotoxicity and genotoxicity of lipid nanocapsules

Lipid nanocapsules (LNCs) offer a promising method for the entrapment and nanovectorisation of lipophilic molecules. This new type of nanocarrier, formulated according to a solvent-free process and using only regulatory-approved components, exhibits many prerequisites for being well tolerated. Although toxicological reference values have already been obtained in mice, interaction of LNCs at the cell level needs to be elucidated. LNCs, measuring from 27.0±0.1nm (25nm LNCs) and 112.1±1.8nm (100nm LNCs) and with a zeta potential between -38.7±1.2mV and +9.18±0.4mV, were obtained by a phase inversion process followed by post-insertion of carboxy- or amino-DSPE-PEG. Trypan blue, MTS and neutral red uptake (NRU) assays were performed to evaluate the cytotoxicity of LNCs on mouse macrophage-like cells RAW264.7 after 24h of exposure. The determination of 50% lethal concentration (LC50) showed a size effect of LNCs on toxicity profiles: LC50 ranged from 1.036mg/L (MTS) and 0.477mg/mL (NRU) for 25nm LNCs, to 4.42mg/mL (MTS) and 2.18mg/mL (NRU) for 100nm LNCs. Surfactant Solutol® HS15 has been shown to be the only constituent to exhibit cytotoxicity; its LC50 reached 0.427mg/mL. Moreover, LNCs were not more toxic than their components in simple mixtures. At sublethal concentration, 100nm LNCs only were able to induce a significant production of nitric oxide (NO) by RAW264.7 cells, as assessed by the Griess reaction. Again, surfactant was the only component responsible for an increased NO release (1.8±0.2-fold). Genotoxicity assays revealed no DNA damage on human lymphocytes in both the in vitro Comet and micronucleus assays using 4-hour and 24-hour treatments, respectively