Population biology of Octopus vulgaris on the temperate south-eastern coast of South Africa

Population structure and biology of Octopus vulgaris was investigated along the south-eastern coast of South Africa. Samples were collected inter- and sub-tidally as a precursor to the establishment of an experimental octopus fishery in the region. In total, 300 (intertidal) and 147 (subtidal) O. vulgaris were collected over a two year period. Females were found to dominate the intertidal area (sex ratio 2:1), while no difference was found subtidally (sex ratio 1:1). Of those collected intertidally, immature females were most prevalent while males ranged from immature to mature. Mature females were only found subtidally. A marked size difference was apparent, with the subtidal octopus being substantially larger. Although brooding females were found throughout the year, numbers peaked in summer. Individual fecundity ranged between 42,000–790,000 eggs. The total number of eggs produced and the number of eggs per egg string were correlated to female size. Diet did not vary greatly between the inter- and sub-tidal areas, with the main prey items being crustaceans, teleosts and octopus. It appears that the immature females use the intertidal area to feed and grow, before migrating to deeper areas to mature and spawn

Emissions testing of loose biomass in Limpopo province of South Africa

Abstract: Southern Africa depends on wood for energy. This affects deforestation and global warming. Loose biomass briquettes can replace round wood and mitigate such problems. Loose biomass derived from agricultural and forestry waste has chemicals like pesticides which can cause unsafe emissions. This paper studies emissions resulting from combustion of such loose biomass collected from Limpopo, a province of South Africa. Twelve loose biomass samples were tested for gases emitted from domestic stove combustion. Exhaust gases were sampled and tested to determine composition and quantities of emitted elements. Both element identification and particulate analysis are reported

Energy content and combustion behaviour of loose biomass available in Limpopo

Solid biomass continues to be the primary energy source for a significant proportion of Sub-Saharan African society. It is estimated that 80% of energy for heating and cooking in this subcontinent is derived from round wood biomass resulting in estimated annual rate of deforestation of 0.7%. This is unsustainable. This is despite the existence of a substantial resource of loose biomass (forest and agricultural residues) that is produced and disposed of annually. However, one major challenge in harnessing loose biomass as a source of energy is low energy density and poor combustion behaviour. Biomass briquetting technologies can be deployed to improve energy density and combustion behaviour of loose biomass. This requires understanding of the energy content in locally available loose biomass sources. This paper investigates the calorific values (energy content) and combustion behaviour of loose biomass collected from a region in the Limpopo Province of South Africa. The aim of the investigation is to understand the energy value and hence viability of using such loose biomass with the overall goal of developing recipes for biomass briquetting in the region. Calorific values were measured for 12 samples of loose biomass and their combustion behaviour analysed. Certain loose biomass sources are then identified as potential briquetting candidates

Aborsie: ’n Juridiese, etiese en regsetiese vraagstuk

In die geledere van skokkende en onetiese dade in die menslike samelewing, beklee aborsie ’n besondere plek. Vir wetenskaplike doeleindes kan aborsie oor die algemeen gedefinieer word as die skeiding van of afdrywing uit die moederlyf van die „produk” van konsepsie, synde ’n fetus (Geldenhuys, 1974:11; O’Donovan 1975:2). ’n Verdere element van die definisie, wat die blote afdrywing van die vrug gewoonlik kwalifiseer, is dat die fetus, met betrekking tot nageboortelike lewe gesproke, nie lewensvatbaar moes gewees het nie. Met die byvoeging van hierdie element tot die eie definisie word tans egter vertoef ten einde eers die belangrike vraag wanneer lewe ontstaan, te beantwoord

Mercury exposure in a low-income community in South Africa

Objectives. To establish whether a specific community in a gold mining area, with potentially associated small-scale gold mining activities, was exposed to mercury. Methods. The community was situated in Mpumalanga, where some potential sources of mercury emissions may have an impact. Adults ≥18 years were considered eligible. Biological monitoring, supported by questionnaires, was applied. Thirty respondents completed the questionnaire which covered demographics, energy use, food and water consumption, neurological symptoms, and confounders such as alcohol consumption and brain injuries. Mercury levels were determined in 28 urine and 20 blood samples of these respondents. Results. Three (15%) of the blood samples exceeded the guideline

Systems thinking: A turning point for improving respectful obstetric care in South African health districts

Poorly functioning health systems and local health systems barriers affect many women giving birth in low- and middle-income countries. The district clinical specialist teams in South Africa are uniquely positioned to provide facilitation and mentoring during interventions for improving the weak primary healthcare system. To ensure success, four key principles should be considered during scale-up of interventions: systems thinking and awareness of contexts and barriers; a focus on sustainability; harnessing factors known to enhance scalability; and respect for human rights and equity. Asking the right questions about the responsibilities of health systems at the micro-, meso- and macro-levels will benefit scale-up processes and sustain innovative pathways to high-quality obstetric care in communities

Genetic variant of canine distemper virus from clinical cases in vaccinated dogs in South Africa

Canine distemper virus (CDV) is a highly contagious viral pathogen of worldwide distribution that can cause lethal disease in domestic dogs and other members of the family Canidae. Genetic diversity is found among reference strains and isolates of CDV, mainly in the haemagglutinin (H) protein, and this may be associated with the increasing incidence of distemper in dogs. CDV was isolated in Vero cells expressing canine signalling lymphocyte activation molecule (Vero.DogSLAM) from peripheralblood mononuclear cells and spleen of clinically diseased, previously vaccinated South African dogs. Direct fluorescence antibody test and electronmicroscopy were used to confirm the isolation procedure. Subsequently, RT-PCR was performed on the cell culture isolates, the amplified products were purified and the complete H gene wassequenced and phylogenetically analysed. The H gene of vaccines in use in South Africa was also sequenced and comparative analyses performed. However, the sequences obtained from the sick dogs showed 100% nucleotide identity and was different to that found in virus strains used in vaccines and in isolates reported from other parts of the world in GenBank. The results suggest that a novel CDV lineage may be present in South Africa and we conclude that a recent reversion of vaccine virus to virulence was not the cause of the clinical signs seen in dogs with a previoushistory of vaccination

Systems thinking: A turning point for improving respectful obstetric care in South African health districts

Poorly functioning health systems and local health systems barriers affect many women giving birth in low- and middle-income countries. The district clinical specialist teams in South Africa are uniquely positioned to provide facilitation and mentoring during interventions for improving the weak primary healthcare system. To ensure success, four key principles should be considered during scale-up of interventions: systems thinking and awareness of contexts and barriers; a focus on sustainability; harnessing factors known to enhance scalability; and respect for human rights and equity. Asking the right questions about the responsibilities of health systems at the micro-, meso- and macro-levels will benefit scale-up processes and sustain innovative pathways to high-quality obstetric care in communities

Investigating current smart production innovations in the machine building industry on sustainability aspects

CITATION: Waibel, M. W., Oosthuizen, G. A. & Du Toit, D. W. 2018. Investigating current smart production innovations in the machine building industry on sustainability aspects. Procedia Manufacturing, 21:774-781, doi:10.1016/j.promfg.2018.02.183.The original publication is available at https://www.sciencedirect.comENGLISH ABSTRACT: Driven by the rising demand for individualized high-tech products the machine building industry continuously introduces a wide variety of smart innovations. Manufacturing companies face growing production requirements which can only be only handled by intelligent systems. During the last decades the trend in manufacturing has shifted from the classic mass production to complex individualized products which have to be produced to compete with the costs of mass products. Smart Production Systems are characterized by its flexibility, resource efficiency, ergonomic design and the ability to integrate customer and business partner into the value creation process. This research study investigates current smart production innovations and trends in the machine building industry. The sustainability aspects and the potential of various smart innovations are outlined.https://www.sciencedirect.com/science/article/pii/S2351978918302233Publisher's versio

The effects of selective laser melting scan strategies on deviation of hybrid parts

CITATION: Hagedorn-Hansen, D., et al. 2017. The effects of selective laser melting scan strategies on deviation of hybrid parts. South African Journal of Industrial Engineering, 28(3):200-212, doi:10.7166/28-3-1862.The original publication is available at http://sajie.journals.ac.zaENGLISH ABSTRACT: The use of additive manufacturing to produce intricate part geometries in the aerospace, medical, and tool-and-die industries is increasingly incorporated in manufacturing process chains. However, the high costs, long production times, and material integrity issues associated with additive manufacturing technologies such as selective laser melting make the process suitable only for certain applications. In order to reduce selective laser melting production costs for selected parts, a combination of selective laser melting and milling can be used. Metal parts produced with this method are referred to as hybrid parts. A challenge in producing hybrid parts is to reduce the geometrical deviation due to process-induced warping. This paper discusses the effects of various laser scan strategies on the deviation of hybrid parts. A newly developed scan strategy is experimentally compared with its commercial counterpart with regard to as-built part warping and porosity. The novel strategy resulted in a significant reduction in warping and porosity.AFRIKAANSE OPSOMMING: Die benutting van toevoegingsvervaardiging vir die produksie van komplekse onderdeel geometrieë in die lugvaart, mediese, en werktuig industrieë word toenemend geïnkorporeer in vervaardigingsproseskettings. Gepaardgaande hoë kostes, lang produksietye, en materiaal integriteitstekortkominge met toevoegingsvervaardiging tegnologieë soos selektiewe laser smelting veroorsaak dat die proses slegs uitvoerbaar is vir sekere toepassings. Ten einde selektiewe laser smelting produksiekoste te verminder vir geselekteerde onderdele, kan ’n kombinasie van selektiewe laser smelting en freesmasjinering geïmplementeer word. Metaal onderdele wat met so kombinasie geproduseer word, word na verwys as hibried onderdele. ’n Uitdaging in die vervaardiging van hibried onderdele is om geometriese afwyking deur skeeftrekking wat deur die proses veroorsaak word, te verminder. Hierdie artikel bespreek die effekte van verskeie laser skandeer strategieë op die afwyking van hibried onderdele. ’n Nuut ontwikkelde skandeer strategie is eksperimenteel vergelyk met ’n kommersiële eweknie met betrekking tot skeeftrekking en porositeit. Die skeeftrekking en porositeit van die nuut uitgevonde strategie is beduidend laer.http://sajie.journals.ac.za/pub/article/view/1862Publisher's versio