101 research outputs found
Fungal phoenix rising from the ashes?
During May 2010, sporocarps of what appeared to be an Armillaria sp. were found in large clumps in historic Kirstenbosch Botanical Gardens on the foot of Table Mountain, Cape Town, South Africa. These sporocarps could be physically linked to the roots of unidentified dead trees and Protea spp. The aim of this study was to identify the Armillaria sp. found fruiting in Kirstenbosch. To achieve this goal isolates were made from the mycelium under the bark of dead roots linked to sporocarps. The ITS and IGS-1 regions were sequenced and compared to sequences of Armillaria spp. available on GenBank. Cladograms were generated using ITS sequences to determine the phylogenetic relationship of the isolates with other Armillaria spp. Sequence comparisons and phylogenetic analyses showed that the isolates represented A. mellea. They were also identical to isolates of this species previously discovered in the Company Gardens in South Africa and introduced from Europe apparently by the early Dutch Settlers. Armillaria mellea is alien and apparently invasive in Cape Town, fruits profusely and has the potential to spread to sensitive native forests on the foothills of the City
Haematological condition of the San (Bushmen) relocated from Namibia to South Africa
No Abstract
Evolution of lifestyles in Capnodiales
The Capnodiales, which includes fungi known as the sooty moulds, represents the second largest order in Dothideomycetes, encompassing morphologically and ecologically diverse fungi with different lifestyles and modes of nutrition. They include saprobes, plant and human pathogens, mycoparasites, rock-inhabiting fungi (RIF), lichenised, epi-, ecto- and endophytes. The aim of this study was to elucidate the lifestyles and evolutionary patterns of the Capnodiales as well as to reconsider their phylogeny by including numerous new collections of sooty moulds, and using four nuclear loci, LSU, ITS, TEF-1α and RPB2. Based on the phylogenetic results, combined with morphology and ecology, Capnodiales s. lat. is shown to be polyphyletic, representing seven different orders. The sooty moulds are restricted to Capnodiales s. str., while Mycosphaerellales is resurrected, and five new orders including Cladosporiales, Comminutisporales, Neophaeothecales, Phaeothecales and Racodiales are introduced. Four families, three genera, 21 species and five combinations are introduced as new. Furthermore, ancestral reconstruction analysis revealed that the saprobic lifestyle is a primitive state in Capnodiales s. lat., and that several transitions have occurred to evolve lichenised, plant and human parasitic, ectophytic (sooty blotch and flyspeck) and more recently epiphytic (sooty mould) lifestyles.</p
Mapping the informal public transport network in Kampala with smartphones : making sense of an organically evolved chaotic system in an emerging city in Sub-Saharan Africa
In cities in the emerging world, public transport networks are governed by a large number of agents, each with their own agendas, priorities, incentives and resources, interacting nonlinearly through complex feedback loops. The transport system in these cities have developed into a semi-chaotic self-organizing structure with seemingly unpredictable behaviour to an outside observer. This is due to user agent actions by passengers, independent determination of operating plans and practices by transport operators, and a managing authority exhibiting a lack of will (both political and institutional), to implement adequate control measures to provide regulation and management of these systems.
Based on the problems that face transport systems in developing cities and public transport in particular, this paper reports on an attempt to understand the supply of public transport in the Kampala area in a novel manner. We describe a mapping approach using a custom-developed smartphone application which was used to quickly and accurately capture informal transport systems for analysis and study of urban mobility where no dependable data was currently available. Secondly, based on the data created by the study project, to provide insights into the routes, operations and characteristics of the minibus taxi network which convey the majority of Kampala?s travelers. Our hypothesis is that by understanding the network in geospatial terms, we will be able to create benefits for all role-players and improve the efficiency and effectiveness of the supply of public transport to more closely match the demand for public transport in an emerging world city.Paper presented at the 35th Annual Southern African Transport Conference 4-7 July 2016 "Transport ? a catalyst for socio-economic
growth and development opportunities to improve quality of life", CSIR International Convention Centre, Pretoria, South Africa.The Minister of Transport, South AfricaTransportation Research Board of the US
In vitro effects of arachidonic acid and prostaglandin E2 on proliferation, osteoclast formation and bone resoption in RAW 264.7 murine macrophages
This study investigated the effects
of arachidonic acid and prostaglandin E2 on osteoclast formation and bone resorption in RAW
264.7 murine pre-osteoclasts. Data obtained suggests an inhibitory effect of these compounds
on osteoclastogenesis and bone resorption in the cell line tested.Die Mediese Navorsingsraad en die Navorsingsontwikkelingsprogram
(Universiteit van Pretoria)http://www.satnt.ac.z
The expression of personality among adolescents exposed to community interpersonal violence
The high level of crime in South Africa affects many adolescents. Experience of community interpersonal violence affects the social, emotional and cognitive functioning of adolescents and could have an impact on their personality development. The aim of the study was to explore possible differences in the expression of personality between adolescents exposed to community interpersonal violence and those not exposed to such violence. The sample
comprised 183 grade 12 learners from a secondary school in a middle class community in Gauteng. Participants were divided into two groups: adolescents who reported exposure to community interpersonal violence (n = 93) and those who did not report exposure to such violence (n = 90). Both groups completed the 16 Personality Factor and Posttraumatic Diagnostic Scales. Differences between the groups were explored using a one-way between groups multivariate analysis of variance (MANOVA) and t-tests for independent groups. Results indicated statistically significant differences between the two groups on Factor G (rule consciousness), Factor I (emotional sensitivity) and Factor Q4 (anxiety). Adolescents exposed to interpersonal violence reported higher levels of posttraumatic stress disorder (PTSD) symptoms than the control group. The group that experienced PTSD symptoms differed more in terms of personality functioning (Factor I and Q4). Violence-exposed adolescents experienced more emotional volatility, difficulty to regulate emotions, anxiety and sensitivity to environmental stressors than those not exposed to such violence. Although causality cannot be assumed, it is possible that exposure to community interpersonal violence, which could result in PTSD symptoms, has implications for the personality development of adolescents. Interventions for adolescents exposed to interpersonal violence are recommended to prevent the development of PTSD symptoms.http://sap.sagepub.comhb2016Psycholog
Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), a potential biological control agent for the submerged aquatic weed, Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae)
The leaf-mining fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), was investigated in its native range in South Africa, to determine its potential as a biological control agent for Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae), an invasive submerged macrophyte that is weedy in many parts of the world. The fly was found throughout the indigenous range of the plant in South Africa. High larval abundance was recorded at field sites with nearly all L. major shoots sampled ontaining larvae, with densities of up to 10 larvae per shoot. Adults laid batches of up to 15 eggs, usually on the abaxial sides of L. major leaves. The larvae mined internally, leaving the epidermal tissues of the upper and lower leaves intact. The larvae underwent three instars which took an average of 24 days and pupated within the leaf tissue, from which the adults emerged. Impact studies in the laboratory showed that H. lagarosiphon larval feeding significantly restricted the formation of L. major side branches. Based on its biology and damage caused to the plant, Hydrellia lagarosiphon could be considered as a useful biological control candidate for L. major in countries where the plant is invasive
Do optional activities matter in virtual learning environments?
Virtual Learning Environments (VLEs) provide students with activi-ties to improve their learning (e.g., reading texts, watching videos or solving exercises). But VLEs usually also provide optional activities (e.g., changing an avatar profile or setting goals). Some of these have a connection with the learn-ing process, but are not directly devoted to learning concepts (e.g., setting goals). Few works have dealt with the use of optional activities and the relation-ships between these activities and other metrics in VLEs. This paper analyzes the use of optional activities at different levels in a specific case study with 291 students from three courses (physics, chemistry and mathematics) using the Khan Academy platform. The level of use of the different types of optional ac-tivities is analyzed and compared to that of learning activities. In addition, the relationship between the usage of optional activities and different student be-haviors and learning metrics is presented
Crescimento e esporulação de Bipolaris euphorbiae cultivado sob diferentes condições nutricionais
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