Skrifbeskouing en oorredingsretoriek: Perspektiewe op performatiewe prediking

This article starts out by giving a brief summary of the typical Reformed understanding of the performative (sacramental) character of Scripture and the implications thereof for preaching. The critique that has been levelled against this understanding of Scripture and preaching, initiated through the mind-set of the Enlightenment (Kant), gaining momentum since the Second World War, and coming to full fruition in the so-called postmodernism, is briefly addressed. The article closes with suggestions concerning the rhetorical strategies of persuasion found in Scripture, and how this maenable preachers to still attain preaching that is “performative”. Article is in Afrikaan

Toward the utilisation of resources in space: knowledge gaps, open questions, and priorities

There are many open science questions in space resource utilisation due to the novelty and relative immaturity of the field. While many potential technologies have been proposed to produce usable resources in space, high confidence, large-scale design is limited by gaps in the knowledge of the local environmental conditions, geology, mineralogy, and regolith characteristics, as well as specific science questions intrinsic to each process. Further, the engineering constraints (e.g. energy, throughput, efficiency etc.) must be incorporated into the design. This work aims to summarise briefly recent activities in the field of space resource utilisation, as well as to identify key knowledge gaps, and to present open science questions. Finally, future exploration priorities to enable the use of space resources are highlighted

Histamine and Tyramine Content of South African Wine

The histamine content of 184 wines and tyramine content of 156 wines, produced in South Africa was measured. The histamine and tyramine content of the wine was found to be similar to those of wines produced in other countries. The average histamine content of South African red wines that had undergone malo-lactic fermentation was more than double that of red wines that had not undergone malo-lactic fermentation. All the red wines containing relatively large amounts of histamine had pH's above 3, 7. Six selected strains of malo-lactic bacteria were tested for their ability to form histamine and tyramine in white and red wine. No histamine or tyramine was formed

The Janus effect: Contradictory demands placed on the academic chairperson

The purpose of this paper is to gain a deeper understanding of the multidimensional nature and complexity of the challenges academic chairpersons appointed at institutions of higher learning experience. A qualitative research approach was chosen to gain a comprehensive understanding of the phenomenon under investigation by means of a focus group of 24 academic chairpersons. The findings indicate that academic chairpersons are inundated with responsibilities. They have to find a balance between the various roles, responsibilities and tasks originating from two opposing roles – that of scholar versus that of administrator/manager/leader – forced into one, while lacking the necessary administrative/managerial/leadership experience, skills and knowledge for their role as managers. This study provides higher education institutions and role-players responsible for the appointment, support and development of academic chairpersons with the evidence required to substantiate the necessity of redesigning this role

The beneficiation of lunar regolith for space resource utilisation: A review

Space Resource Utilisation (SRU) technology will enable further exploration and habitation of space by humankind. The production of oxygen on the Moon is one of the first objectives for SRU; this can be achieved through the thermo-chemical reduction of the lunar regolith. Several techniques, such as hydrogen reduction and molten salt electrolysis, have been proposed. All reduction techniques require a consistent feedstock from the regolith to reliably and consistently produce oxygen. The preparation of this feedstock, known as beneficiation, is a critical intermediate stage of the SRU flowsheet, however it has received little consideration relative to the preceding excavation, and the subsequent oxygen production stage. This review describes the physics of the main beneficiation methods suitable for SRU. Further, we collate and review all of the previous studies on the beneficiation of lunar regolith

Estimating ionospheric currents by inversion from ground-based geomagnetic data and calculating geoelectric fields for studies of geomagnetically induced currents

This research focuses on the inversion of geomagnetic variation field measurements to obtain the source currents in the ionosphere and magnetosphere, and to determine the geoelectric fields at the Earth’s surface. During geomagnetic storms, the geoelectric fields create geomagnetically induced currents (GIC) in power networks. These GIC may disturb the operation of power systems, cause damage to power transformers, and even result in power blackouts. In this model, line currents running east–west along given latitudes are postulated to exist at a certain height above the Earth’s surface. This physical arrangement results in the fields on the ground being composed of a zero magnetic east component and a nonzero electric east component. The line current parameters are estimated by inverting Fourier integrals (over wavenumber) of elementary geomagnetic fields using the Levenberg–Marquardt technique. The output parameters of the model are the ionospheric current strength and the geoelectric east component at the Earth’s surface. A conductivity profile of the Earth is adapted from a shallow layered-Earth model for one observatory, together with a deep-layer model derived from satellite observations. This profile is used to obtain the ground surface impedance and therefore the reflection coefficient in the integrals. The inputs for the model are a spectrum of the geomagnetic data for 31 May 2013. The output parameters of the model are spectrums of the ionospheric current strength and of the surface geoelectric field. The inverse Fourier transforms of these spectra provide the time variations on the same day. The geoelectric field data can be used as a proxy for GIC in the prediction of GIC for power utilities. The current strength data can assist in the interpretation of upstream solar wind behaviour

Towards Green(er) Cities: Contextualizing Green Benefits for Urban Spaces and Contemporary Societies

&lt;p&gt;There is an expanding understanding of the value and critical need for green(er) cities. It comes at a time when green spaces are depleting on a global scale, in order for cities to host the majority of the world’s population. The contest between diverse land-uses is inflating the pressure on already strained resources, intensifying the growing carbon footprint and impairing water quality, and compromising health and overall quality of life. Soon our cities will be far removed from the safe, clean, and liveable environments, as envisioned in planning theory, if we continue with business-as-usual. There is an increasing scientific appreciation of the interrelated role of green land-uses, the value of our environment and its related ecosystem services, which acts as catalyst to realise the objectives of broader sustainability. Although literature is clear on the importance, role, benefits, and impact of green(er) cities, the realisation of the greening initiatives in practice is still limited, and more should be done to embed green(er) thinking as part of mainstream urban planning. Urban spatial transformation is needed to reclaim nature for cities and to enhance the direct and indirect benefits that nature provides to contemporary societies. This thematic issue considered various trans-disciplinary approaches to provide a way forward in the quest of prioritising the notion of green(er) cities, while drawing on a range of evidence-led initiatives.&lt;/p&gt;</jats:p

Congenital eunuchism and favorinus

Ancient Hebrew literature as well as the New Testament differentiate between castrated eunuchs and congenital eunuchs. Congenital eunuchism is very rare today, and assuming that this was also the case in classical times, we investigated possible reasons why congenital eunuchs feature prominently. We discuss the probability that the concept `congenital eunuchism' might in ancient times have included effeminate men who, according to cultural views on `maleness' and androgyny, were almost equated with eunuchs. The causes of congenital hypogonadism are reviewed in order to attempt clarification of the condition of Favorinus, a congenital eunuch in the second century AD. We suggest that although he might have been a true hermaphrodite, as suggested by some s, it is more likely that he had one of the following conditions: functional prepubertal castrate syndrome, testicular gonadotrophin insensitivity, selective gonadotrophin deficiency or Reifenstein's syndrome. (South African Medical Journal: 2003 93(1): 73-76

GPS TEC and ionosonde TEC over Grahamstown, South Africa: first comparisons

The Grahamstown, South Africa (33.3°S, 26.5°E) ionospheric field station operates a UMass Lowell digital pulse ionospheric sounder (Digisonde) and an Ashtech geodetic grade dual frequency GPS receiver. The GPS receiver is owned by Chief Directorate Surveys and Mapping (CDSM) in Cape Town, forms part of the national TrigNet network and was installed in February 2005. The sampling rates of the GPS receiver and Digisonde were set to 1 s and 15 min, respectively. Data from four continuous months, March–June 2005 inclusive, were considered in this initial investigation. Data available from the Grahamstown GPS receiver was limited, and, therefore, only these 4 months have been considered. Total Electron Content (TEC) values were determined from GPS measurements obtained from satellites passing near vertical (within an 80° elevation) to the station. TEC values were obtained from ionograms recorded at times within 5 min of the near vertical GPS measurement. The GPS derived TEC values are referred to as GTEC and the ionogram derived TEC values as ITEC. Comparisons of GTEC and ITEC values are presented in this paper. The differential clock biases of the GPS satellites and receivers are taken into account. The plasmaspheric contribution to the TEC can be inferred from the results, and confirm findings obtained by other groups. This paper describes the groundwork for a procedure that will allow the validation of GPS derived ionospheric information with ionosonde data. This work will be of interest to the International Reference Ionosphere (IRI) community since GPS receivers are becoming recognised as another source for ionospheric information