Comparative study of skipjack tuna Katsuwonus pelamis (Scombridae) fishery stocks from the South Atlantic and western Indian oceans
- Authors: Dahlet, Lol I , Downey-Breedt, Nicola , Arce, Gabriel , Sauer, Warwick H H , Gasalla, Maria A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123988 , vital:35523 , https://doi.org/10.3989/scimar.04804.22C
- Description: Temporal and spatial fluctuations in the abundance of oceanic pelagic populations spread geographically around the globe are common (Cushing 1975). The causes of these fluctuations may be exogenous (environmental or anthropogenic) or endogenous to the organism (e.g. ontogenetic drivers) (Ricker 1954). This scenario applies to some tuna stocks, including the skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758), known as bonito-listrado in Brazil, katunkel, or ocean bonito in South Africa, and godhaa (bigger) or kadumas (smaller) skipjack in the Maldives. The skipjack belongs to the family Scombridae and inhabits tropical and subtropical areas of the globe. On average, 85% of skipjack catch occurs in waters warmer than 24°C (Fonteneau 2003). This resource is of particular importance, accounting for 57% of the global industrial tuna catch in 2016, and is mainly processed by the canning industry. Skipjack catches totaled 2.79 million t in 2016 (ISSF 2018), and currently 8.5% of worldwide catches are made by the pole-and line fleet. In Brazil and the Maldives, the resource is well-known. Catches in Brazil were seen to increase until 2014, while in the Maldives, 2006 marked the beginning of a strong and unsettling decline that continued until recent years. Off South Africa, skipjack catches are 1000 to 10000 times lower than those from Brazil and the Maldives, and the highest catches were recorded in 2012.
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Cosmolocal orientations: trickster spatialization and the politics of cultural bargaining in Zambia
- Authors: Simbao, Ruth K
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146044 , vital:38490 , DOI 10.1080/19301944.2018.1532379
- Description: The spatialization of Africa is fraught, and places within Africa tend to be stereotyped by geographies of morality and simplistic rural/urban divides. Focusing on the spatial, cultural, and political bargaining of contemporary chiefs and cultural festivals in 21st-century Zambia, this article delinks cosmopolitanism and Afropolitanism from the city and associated attitudes of urbanity. Positioning place as a trickster character, it argues for a nuanced understanding of time-space imaginaries that refuses to bind people and identities to closed-down notions of place. In this article I propose the term cosmolocal, suggesting that the cosmolocal is an outward-engaging orientation that understands place as a profoundly discursive and situational process and that has the potential to exist anywhere. Many contemporary chiefs in Zambia embrace cosmolocalism, enabling them to escape the limitations of being viewed merely as custodians of culture who are limited to the space of the village framed historically as the warehouse of culture.
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Deeper knowledge of shallow waters: reviewing the invertebrate fauna of southern African temporary wetlands
- Authors: Bird, Matthew S , Mlambo, Musa C , Wasserman, Ryan J , Dalu, Tatenda , Holland, Alexandra J , Day, Jenny A , Villet, Martin H , Bilton, David T , Barber-James, Helen M , Brendonck, Luc
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140784 , vital:37918 , DOI: 10.1007/s10750-018-3772-z
- Description: Temporary lentic wetlands are becoming increasingly recognised for their collective role in contributing to biodiversity at the landscape scale. In southern Africa, a region with a high density of such wetlands, information characterising the fauna of these systems is disparate and often obscurely published. Here we provide a collation and synthesis of published research on the aquatic invertebrate fauna inhabiting temporary lentic wetlands of the region. We expose the poor taxonomic knowledge of most groups, which makes it difficult to comment on patterns of richness and endemism.
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Environmental niche patterns of native and non-native fishes within an invaded African river system
- Authors: Kadye, Wilbert T , Booth, Anthony J
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124407 , vital:35605 , https://doi.10.1111/jfb.13988
- Description: To test ecological niche theory, this study investigated the spatial patterns and the environmental niches of native and non-native fishes within the invaded Great Fish River system, South Africa. For the native fishes, there were contrasting environmental niche breadths that varied from being small to being large and overlapped for most species, except minnows that were restricted to headwater tributaries. In addition, there was high niche overlap in habitat association among fishes with similar distribution. It was therefore inferred that habitat filtering-driven spatial organization was important in explaining native species distribution patterns. In comparison, most non-native fishes were found to have broad environmental niches and these fishes showed high tolerance to environmental conditions, which generally supported the niche opportunity hypothesis. The proliferation of multiple non-native fishes in the mainstem section suggest that they form a functional assemblage that is probably facilitated by the anthropogenic modification of flow regimes through inter-basin water transfer. Based on the distribution patterns observed in the study, it was inferred that there was a likelihood of negative interactions between native and nonnative fishes. Such effects are likely to be exacerbated by altered flow regime that was likely to have negative implications for native ichthyofauna.
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Governance mapping: a framework for assessing the adaptive capacity of marine resource governance to environmental change
- Authors: Dutra, Leo X C , Sporne, Ilva , Haward, Marcus , Aswani, Shankar , Cochrane, Kevern L , Frusher, Stewart , Gasalla, Maria A , Gianesella, Sônia M F , Grant, Tanith , Hobday, Alistair J , Jennings, Sarah , Plagányi, Éva , Pecl, Gretta T , Salim, Shyam S , Sauer, Warwick H H , Taboada, Manuela B , Van Putten, Ingrid E
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145336 , vital:38429 , DOI: 10.1016/j.marpol.2018.12.011
- Description: Marine social-ecological systems are influenced by the way humans interact with their environment, and external forces, which change and re-shape the environment. In many regions, exploitation of marine resources and climate change are two of the primary drivers shifting the abundance and distribution of marine living resources, with negative effects on marine-dependent communities. Governance systems determine ‘who’ makes decisions, ‘what’ are their powers and responsibilities, and ‘how’ they are exercised. Understanding the connections between the actors comprising governance systems and influences between governance and the environment is therefore critical to support successful transitions to novel forms of governance required to deal with environmental changes. The paper provides an analytical framework with a practical example from Vanuatu, for mapping and assessment of the governance system providing for management of coral reef fish resources. The framework enables a rapid analysis of governance systems to identify factors that can encourage, or hinder, the adaptation of communities to changes in abundance or availability of marine resources.
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Identification of Novel Potential Inhibitors of Pteridine Reductase 1 in Trypanosoma brucei via Computational Structure-Based Approaches and in Vitro Inhibition Assays
- Authors: Kimuda, Magambo Phillip , Laming, Dustin , Hoppe, Heinrich C , Tastan Bishop, Özlem
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124675 , vital:35647 , https://doi:10.3390/molecules24010142
- Description: Pteridine reductase 1 (PTR1) is a trypanosomatid multifunctional enzyme that provides a mechanism for escape of dihydrofolate reductase (DHFR) inhibition. This is because PTR1 can reduce pterins and folates. Trypanosomes require folates and pterins for survival and are unable to synthesize them de novo. Currently there are no anti-folate based Human African Trypanosomiasis (HAT) chemotherapeutics in use. Thus, successful dual inhibition of Trypanosoma brucei dihydrofolate reductase (TbDHFR) and Trypanosoma brucei pteridine reductase 1 (TbPTR1) has implications in the exploitation of anti-folates. We carried out molecular docking of a ligand library of 5742 compounds against TbPTR1 and identified 18 compounds showing promising binding modes. The protein-ligand complexes were subjected to molecular dynamics to characterize their molecular interactions and energetics, followed by in vitro testing. In this study, we identified five compounds which showed low micromolar Trypanosome growth inhibition in in vitro experiments that might be acting by inhibition of TbPTR1. Compounds RUBi004, RUBi007, RUBi014, and RUBi018 displayed moderate to strong antagonism (mutual reduction in potency) when used in combination with the known TbDHFR inhibitor, WR99210. This gave an indication that the compounds might inhibit both TbPTR1 and TbDHFR. RUBi016 showed an additive effect in the isobologram assay. Overall, our results provide a basis for scaffold optimization for further studies in the development of HAT anti-folates.
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Rethinking the dialectics of rural and urban in African art and scholarship:
- Authors: Siegenthaler, Fiona , Nzewi, Ugochukwu-Smooth C , Siegert, Nadine
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146022 , vital:38488 , DOI: 10.1080/19301944.2018.1538856
- Description: This issue of Critical Interventions is dedicated to rethinking the dialectics of the rural and the urban in African art and scholarship. Inspired by the general theme of the European Conference of African Studies (ECAS/AEGIS) in Basel (June 28 to July 1, 2017), Urban Africa – Urban Africans: New Encounters of the Rural and the Urban, the guest editors of this issue hosted two panels on the relationship of urban-based artists and their interest in rural topographies, aesthetics, and cultural practices.
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The Art of Life in South Africa by Daniel Magaziner: a review
- Authors: Ijisakin, Eyitayo Tolulope
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146101 , vital:38495 , https://www.muse.jhu.edu/article/702008
- Description: In The Art of Life in South Africa, Daniel Magaziner examines the history of art education under apartheid in South Africa. The book focuses on Ndaleni, an art school for black South Africans, and considers the travails and triumphs of its artists and their teachers under white supremacy. At Ndaleni, students and teachers were bound together in learning “the art of life”; due to lack of funds, they improvised materials for artistic production. While the school existed, between the 1950s and 1980s, about 1,000 students graduated; about 2,000 could not be admitted due to constraints of space. This shows how Ndaleni appealed to many black South Africans as one of the few places they could develop their art. According to the Bantu Education Act of 1953 (p. 3), the purpose of the school was to preserve white supremacy, the segregation between African and European education—what Oguibe (2004) refers to as “Play me the other.” The book is organized into seven chapters, with a prologue, an epilogue, and endnotes.
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‘Yummy or crummy?': the multisensory components of medicines-taking among HIV-positive youth
- Authors: Hodes, Rebecca , Vale, Beth , Toska, Elona , Cluver, Lucie , Dowse, Roslind , Ashorn, Mikael
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156663 , vital:40036 , DOI: 10.1080/17441692.2018.1504103
- Description: The global rollout of Antiretroviral Treatment (ART) has revealed an urgent need to understand the medicines-taking practices of HIV-positive adolescents. In the last decade, the literature on the social determinants of health has broadened the evidence-base on ART adherence. Interdisciplinary studies have expanded conceptions of medicines-taking beyond clinical or health systems frameworks, recognising the importance of socio-structural conditions and of patients’ beliefs and experiences. Participatory research techniques which foreground the perspectives of adolescents provide greater insights still into their adherence. This article explores the use of participatory methods within a broader study on the social determinants of ART adherence among HIV-positive adolescents in South Africa. We describe how participatory methods were incorporated into this study (n = 1,059 in the quantitative baseline). We focus on an exercise, ‘Yummy or crummy?’, that explored the multisensory dimensions of medicines-taking, including their colour, smell, shape, and delivery mechanism. We describe two principal findings: first, adolescents’ preference for greater understanding of the chemical workings of medicines, manifested in their preferences for colour, taste and shape of medicines; and second, the vital relationship between sensory preferences and the social imperatives of discretion and confidentiality regarding HIV-status.
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Mbeki's African Renaissance Vision as Reflected in isiXhosa Written Poetry: 2005–2011
- Authors: Mona, Godfrey V , Kaschula, Russell H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/174705 , vital:42502 , ttps://doi.org/10.1080/18186874.2018.1457616
- Description: IsiXhosa literary critics have not yet interrogated literature that was produced during and after the tenure of Thabo Mvuyelwa Mbeki as deputy president and president of the Republic of South Africa in order to study the impact of his African Renaissance doctrine. This article analyses poetry that was produced from 2005 to 2011. The content of the isiXhosa written poetry is profoundly influenced by the context of former President Mbeki's African Renaissance philosophy, its implementation structures and philosophy of self-confidence and self-reliance. The selected poems analysed and interpreted in this article suggest that Mbeki's legacy of the African Renaissance empowered poets to develop a narrative that advances the building of a regenerated South African nation and the African continent.
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The relation between galaxy density and radio jet power for 1.4 GHz VLA selected AGNs in Stripe 82
- Authors: Kolwa, S , Jarvis, M J , McAlpine, Kim , Heywood, Ian
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131444 , vital:36572 , https://doi.org/10.1093/mnras/sty3019
- Description: Using a Karl G. Jansky Very Large Array (VLA) L-band (1-2 GHz) survey covering ∼100 deg2 of the Stripe 82 field, we have obtained a catalogue of 2716 radio AGNs. For these AGNs, we investigate the impact of galaxy density on 1.4 GHz radio luminosity (L1.4). We determine their close environment densities using the surface density parameter, ΣN, for N = 2 and N = 5, which we bin by redshift to obtain a pseudo-3D galaxy density measure. Matching the radio AGNs to sources without radio detections in terms of redshift, K-band magnitude and (g − K) colour index, we obtain samples of control galaxies and determine whether radio AGN environments differ from this general population.
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