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54. The Bulletin's Constituent Parts.

Author

Bradfield, Justin

Abstract

The article focuses on clarifying the distinction between field and technical reports and research articles in the Bulletin of the Southern African Humanities, emphasizing that both types undergo peer review and carry equal weight. It mentions the history of the Bulletin's sections, the purpose of the Field and Technical Reports section, and examples from the current issue are discussed to provide insight into the contributions expected in this section.

Published
2023

55. The Current Occupation of Kruger Cave, A Later Stone Age Site, South Africa

Author

Bradfield, Justin

Abstract

Contemporary occupation of archaeological sites is fraught with challenges and conflicting priorities. While prevailing opinion on heritage management recognises the fluid and continuous nature of archaeological site formation, the role of present-day communities as agents of archaeological palimpsests is often not adequately acknowledged. Contemporary communities, often unrelated to the autochthonous inhabitants of the archaeological sites, occasionally use these sites and landscapes in similar or different ways to how they were used in the past. Their use of these sites, while potentially damaging to the archaeology, simultaneously adds to, and is part of, the life history of the site, of which the excavated material and rock art are but pictures in time. Squatters who appropriate archaeological heritage sites constitute ambiguous communities under current South African heritage legislation. Yet, their role as contributing agents to archaeological sites is no less real. This article presents the case study of Kruger Cave, a Later Stone Age hunter-gatherer rock art site in South Africa, currently occupied by a lay Christian pastor. We document how the pastor is using the site and offer some thoughts around the nuances of negotiating and reconciling archaeological preservation and living heritage management.

Published
2021
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59. Potential for identifying plant-based toxins on San hunter-gatherer arrowheads

Author

Wooding, Madelien, Bradfield, Justin, Maharaj, Vinesh, Koot, Dwayne, Wadley, Lyn, Prinsloo, Linda C, Lombard, Marlize, Wooding, Madelien, Bradfield, Justin, Maharaj, Vinesh, Koot, Dwayne, Wadley, Lyn, Prinsloo, Linda C, and Lombard, Marlize

Abstract

The antiquity of the use of hunting poisons has received much attention in recent years. In this paper we present the results of a pilot study designed to detect the presence of organic compounds, typically of less than 1200 Da, from poisonous plants that may have been used as hunting poisons in the past. We used ultra-performance liquid chromatography connected to a Synapt G2 high-resolution MS-QTOF mass spectrometer (UPLC-QTOF-MS) to provisionally identify plant-based toxins present in (1) extracts of fresh plant material, (2) a blind control recipe consisting of three plant ingredients and (3) a Hei||om arrow poison of unknown ingredients. Although not all expected toxic compounds were identified, those that were identified compared favourably with those reported in the literature and confirmed through databases, specifically the Dictionary of Natural Products and ChemSpider. MS/MS fragmentation patterns and accurate mass were used for tentative identification of compounds because archaeological residues usually contain insufficient material for unambiguous identification using nuclear magnetic resonance. We highlight the potential of this method for accurately identifying plant-based toxins present on archaeological artefacts and unique (albeit non-toxic) chemical markers that may allow one to infer the presence of toxic plant ingredients in arrow poisons. Any chemical study of archaeological material should consider the unique environmental degradative factors and be sensitive to the oxidative by-products of toxic compounds.

Published
2017

60. UHF Phased Array Ground Stations for Cubesat Applications

Author

Sheldon, Colin, Bradfield, Justin, Sanchez, Erika, Boye, Jeffrey, Copeland, David, and Adams, Norman

Abstract

We propose and demonstrate a commercial off-the-shelf (COTs) component based cubesat phased array ground station that offers multiple simultaneous beams for communicating with and localizing multiple visible cubesats. The ground station uses a receiver digital beamformer based on low cost software defined radios at each antenna element. Phased array antennas provide spectrum reuse through spatial multiplexing, localization and tracking capabilities and interference rejection through steerable nulls to mitigate the effects of in-band terrestrial interferers. Growing interest in cubesats will lead to an increasingly crowded sky. Cubesat constellations may become increasingly common as the user community expands. Uncertainty in cubesat release conditions and limited sensor capability on the cubesat leads to uncertainty in post deployment cubesat position. Traditional ground stations are not designed to work in this environment. Proposed phased array ground station services include publishing beams from the digital beamformer, allowing users to subscribe to the beams of interest at the times of interest. This represents a fundamental change in the traditional ground station user interface which typically relies on scheduling ground station time for each user in advance. A global network of phased array ground stations would enable the user community to take full advantage of their cubesats.

Published
2016

66. Southern African arrow poison recipes, their ingredients and implications for Stone Age archaeology.

Author

Bradfield, Justin, Wadley, Lyn, and Lombard, Marlize

Subjects
ARROW poisons, STONE Age, ANTIQUITIES, BIOCHEMICAL toxicology, HUNTING
Abstract

Biochemical analyses of residues preserved on ethno-historical and archaeological artefacts increase our understanding of past indigenous knowledge systems. The interpretation of biochemical traces is, however, difficult. Problems that can hamper credible interpretations of ethno-historical or archaeological residues include incomplete knowledge about local natural products, limited published data about product applications, and overestimation of the abilities of the analytical techniques to make specific identifications. In an initial attempt to address some of the challenges, we discuss arrow poison as a case in point, and we provide complete, updated inventories of known southern African poison ingredients and recipes, suspected poisons, and the current state of knowledge about these toxins and their effects. We also suggest that discoveries of ancient arrow poison, and the technical steps involved in early toxicology, have the potential to indicate levels of human cognition. [ABSTRACT FROM AUTHOR]

Published
2015

67. Pointed bone tool technology in southern Africa: results of use-trace analyses.

Author

Bradfield, Justin

Subjects
BOW & arrow, MATERIAL culture, TAPHONOMY, STONE Age, ARCHAEOLOGICAL site location
Abstract

Bone tools represent an important but often understudied aspect of past material culture. Apart from some notable exceptions, bone tool studies are still dominated by typological descriptions. This paper reviews the history and current state of bone tool functional studies in southern Africa. I present the results of use-trace analyses of 378 bone points from 12 archaeological sites spanning the last 18 000 years. The results suggest that manufacturing techniques remain unchanged for most of the time span considered. Damage on the distal ends indicates that not all bone arrow points were pointed, but that some arrows may have included a metal or stone tip. On certain specimens, use-wear and residue remains suggest that at least some bone points (morphologically identical to San bone arrow components) may have been used to process plant material. Whether they were used solely for this purpose or as multifunctional tools is uncertain. The most variability in use-trace indicators on bone points occurs during the Wilton, particularly after 4000 BP. Such changes in bone point form and function do not correlate neatly with lithic technological oscillations. It is not certain to what extent this pattern is a reflection of taphonomic conditions. [ABSTRACT FROM AUTHOR]

Published
2015

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