Causes of decoupling between larval supply and settlement and consequences for understanding recruitment and population connectivity
- Authors: Pineda, Jesus , Porri, Francesca , Starczak, Victroria , Blythe, Jonathan
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6869 , http://hdl.handle.net/10962/d1011501
- Description: Marine broadcast spawners have two-phase life cycles, with pelagic larvae and benthic adults. Larval supply and settlement link these two phases and are crucial for the persistence of marine populations. Mainly due to the complexity in sampling larval supply accurately, many researchers use settlement as a proxy for larval supply. Larval supply is a constraining variable for settlement because, without larval supply, there is no settlement. Larval supply and settlement may not be well correlated, however, and settlement may not consistently estimate larval supply. This paper explores the argument that larval supply (i.e., larval abundance near settlement sites) may not relate linearly to settlement. We review the relationship between larval supply and settlement, from estimates and biases in larval supply sampling, to non-behavioral and behavioral components, including small-scale hydrodynamics, competency, gregarious behavior, intensification of settlement, lunar periodicity, predation and cannibalism. Physical and structural processes coupled with behavior, such as small-scale hydrodynamics and intensification of settlement, sometimes result in under- or overestimation of larval supply, where it is predicted from a linear relationship with settlement. Although settlement is a function of larval supply, spatial and temporal processes interact with larval behavior to distort the relationship between larval supply and settlement, and when these distortions act consistently in time and space, they cause biased estimates of larval supply from settlement data. Most of the examples discussed here suggest that behavior is the main source of the decoupling between larval supply and settlement because larval behavior affects the vertical distribution of larvae, the response of larvae to hydrodynamics, intensification of settlement, gregariousness, predation and cannibalism. Thus, larval behavior seems to limit broad generalizations on the regulation of settlement by larval supply. Knowledge of the relationship is further hindered by the lack of a well founded theoretical relationship between the two variables. The larval supply–settlement transition may have strong general consequences for population connectivity, since larval supply is a result of larval transport, and settlement constrains recruitment. Thus, measuring larval supply and settlement effectively allows more accurate quantification and understanding of larval transport, recruitment and population connectivity.
- Full Text:
- Date Issued: 2010
Consumer health informatics in the information age and beyond
- Authors: Pottas, Dalenca
- Subjects: Medical informatics , Information technology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20757 , vital:29386
- Description: This paper reviews current and future trends and challenges in the field of consumer health informatics. Emergent innovations driving consumer health informatics in the information age include devices, tools and applications supporting personalised healthcare, electronic personal health record (PHR) systems and a plethora of tools in the health social media domain. Within this domain, a new kind of social media citizen, the consumer specialist or patient opinion leader, is taking the lead in online communities of patients. A new generation of personal health records combining PHRs and social media is emerging, even though pervasive adoption and use of PHRs remains elusive. The accuracy of information, security and privacy of personal health information, legislative matters and the digital divide remain recurring challenges of consumer health informatics. In future, PHR vendors will have to address the lack of espousal of PHRs in innovative ways to provide a compelling case for adoption. The continued uptake of health social media necessitates efforts to understand, through longitudinal studies, precisely who the users are, what they use it for and how it contributes to the achievement of both personal and public health outcomes. Health information consumers, of varying levels of techno-literacy, needs and preferences, must be assisted to move from simply accessing information to distilling relevant and credible information and making informed decisions. Further research is required to understand the changing relationships between patients and healthcare providers and how consumer health information technologies can best support these. There is a need to evaluate the effectiveness of consumer health information technologies to inform both public policy and the next generation of tools, technologies and artefacts that could better facilitate improved health outcomes. Lastly, more effort is required to erode digital inequalities. As we move into a future emphasising both the global and the individual, accelerated connectedness and speed of change, consumer health informatics must respond such that it remains germane and amplifies the value that can be gained by all stakeholders.
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Dancing around the same spot? land reform and Ngos in Zimbabwe: the case of SOS Children’s Villages
- Authors: Helliker, Kirk D
- Date: 2009
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61006 , vital:27910 , http://dx.doi.org/10.4314/asr.v13i2.60408
- Description: This paper discusses the rural-based operations of an international NGO in Mashonaland Central province, Zimbabwe. The aim is to highlight the contingent variation of NGO practices within defined limits. It does this through 'thick description’ of the NGO of focus, the SOS Children’s Village, and compares its 'handling' of the transforming countryside with the response of two other NGOs. It concludes by suggesting some conceptual points in understanding organizational dispositions of NGOs.
- Full Text:
- Date Issued: 2009
Demystifying leadership connectivity: rediscovering the soul of leadership
- Authors: Poisat, Paul
- Subjects: Leadership , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/35773 , vital:33811
- Description: INTRODUCTION: A Google search on ‘leadership’ produced 4.2 million articles, books, blogs and webinars on how to become a better leader. Most of the literature, comprising experts and the popular press, abound with formulistic prescriptive steps endorsed by two or three iconic figures that support their regimen. Regardless of the plethora of literature in leadership providing practical and logical tactics, many fall short on implementation and thus result in failure. What numerous sources fail to acknowledge is that the great leaders apply these tactics together with their innate skills to offer clear direction for themselves and their followers. Providing a clear vision and/or strategy to deal with uncertainty and ambiguity is one of the foremost abilities distinguishing leaders in our rapidly changing world and the ability to take employees with them. In addition, various individual (personality, values, cultural, ability) and contextual (nature of the business, complexity, rate of change, work team, diversity) factors may contribute to leadership failure that is characterised by a lack of vision, uncertainty, bullying, management by exclusion, and in extreme cases fraud and corruption. Regardless of the proliferation of leadership literature the world has never been more desperate for sound leadership. We have enough leaders but not enough leadership. With all the literature on leadership, how do you find the essence of leadership?
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Economic review 2001
- Authors: DITSELA
- Date: 2001
- Subjects: Development Institute for Training,Support and Education for Labour (DITSELA)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/178602 , vital:42958
- Description: This volume of Bargaining Indicators for 2002 comes in the context of the September 11 attacks on the World Trade Center in New York, the United States’ war on Afghanistan, the collapse of the economy of Argentina and with it the biggest sovereign bankruptcy in history. All these historic events are unfolding within the first synchronised global recession since the 1970s, and have in turn deepened this recession. Within South Africa, this edition of Bargaining Indicators comes in the context of the first anti-government national strike by organised labour since the 1994 elections, and a deepening of the economic slowdown that we noted in the last edition of Bargaining Indicators. In this review of economic developments during 2001 we shine the spotlight on the global recession and its dynamics, and we look in particular at the slide of the world’s largest economy - that of the United States - into its first serious economic crisis since the end of the cold war, and we take a look at the significance of the attacks of September 11 and their aftermath on the dynamics of the global recession. We conclude our discussion of the global recession by discussing the responses of the Bush government and its allies, and at the meaning of these responses for neoliberal economic orthodoxy. We continue our analysis by looking at developments within the South African economy. In particular, we look at the implications of the global recession on the South African economy, and at how the currency crisis that has unfolded since the last quarter of 2001 forms an important moment in the dynamics of the unfolding global recession. Within this context we look at the main economic indicators (GDP; GDE; fixed capital formation, operating surpluses, wages, employment, savings and so on). Lastly, we look at the year ahead, and in particular at the implications of the global and domestic economic developments for the 2002 bargaining season.
- Full Text:
- Date Issued: 2001
Form over function? The practical application of the Recognition of Customary Marriages Act 1998 in South Africa
- Authors: Kruuse, Helen
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54094 , vital:26389 , http://journals.co.za/content/ju_jur/2013/1/EJC148455
- Description: The Recognition of Customary Marriages Act 120 of 1998 is a major legislative measure for the development of customary marriages in line with the constitutional principle of equality, specifically for women. The article explores the interactions between this ideal in the Act with empirical observations and the latest judicial decisions concerning its application. It considers various examples of the lack of protection of women in relationships of a customary nature, and it concludes that both the state and courts favour a formal or definitional approach to customary marriage. In considering alternative approaches that could adequately protect vulnerable parties, two conclusions emerge: First, the article recommends a wholesale revision of the South African family law approach from a focus on form to dependency. Second (and as a short-term measure), the article advocates for the putative marriage doctrine to be applied in the customary marriage context to protect many women who are denied access to 'customary marriage' as a form, and as a result, all of the benefits that flow from such marriage.
- Full Text:
- Date Issued: 2013
Guarded visions: walls, watchtowers and warped perspectives in the Israeli occupied West Bank Palestinian territory
- Authors: Baasch, Rachel M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147281 , vital:38611 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC176318
- Description: This paper examines the relationship between Israel's fortification of physical space and narratives of division in the Israeli occupied Palestinian West Bank Territory. I argue that the fortification and separation of physical space deepens segregation, and increases fear, hostility and disconnection between people living in this context. Furthermore, I suggest that this relationship between narratives of division and insecurity and structural mechanisms of control within the West Bank influences and impacts on individuals such that personal perspectives become guarded and defensive. The mediation of subjects through a defensive lens can prevent individuals from forming connections that acknowledge the permeability of seemingly impenetrable distinctions between inside and outside, or self and an-other. The looking, recording and representation of people in a place that is guarded and framed from a position of insecurity reduces the capacity of individuals to locate openings that traverse restrictive boundaries. In order to contextualise my discussion, I have included personal documentation of defensive structures photographed in the West Bank between 2013 and 2014. I position my observations and analyses in relation to discussions about the Oush Grab Military Base presented by the Decolonizing Architecture Art Residency (DAAR) in their recent publication Architecture after revolution (2013).
- Full Text:
- Date Issued: 2015
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.
- Full Text:
- Date Issued: 2019
Impact of climate change and development scenarios on flow patterns in the Okavango River
- Authors: Andersson, L , Wilk, J , Todd, M C , Hughes, Denis A , Earle, A , Kniveton, D , Layberry, R , Savenije, H H G
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7086 , http://hdl.handle.net/10962/d1012346
- Description: This paper lays the foundation for the use of scenario modelling as a tool for integrated water resource management in the Okavango River basin. The Pitman hydrological model is used to assess the impact of various development and climate change scenarios on downstream river flow. The simulated impact on modelled river discharge of increased water use for domestic use, livestock, and informal irrigation (proportional to expected population increase) is very limited. Implementation of all likely potential formal irrigation schemes mentioned in available reports is expected to decrease the annual flow by 2% and the minimum monthly flow by 5%. The maximum possible impact of irrigation on annual average flow is estimated as 8%, with a reduction of minimum monthly flow by 17%. Deforestation of all areas within a 1 km buffer around the rivers is estimated to increase the flow by 6%. However, construction of all potential hydropower reservoirs in the basin may change the monthly mean flow distribution dramatically, although under the assumed operational rules, the impact of the dams is only substantial during wet years. The simulated impacts of climate change are considerable larger that those of the development scenarios (with exception of the high development scenario of hydropower schemes) although the results are sensitive to the choice of GCM and the IPCC SRES greenhouse gas (GHG) emission scenarios. The annual mean water flow predictions for the period 2020–2050 averaged over scenarios from all the four GCMs used in this study are close to the present situation for both the A2 and B2 GHG scenarios. For the 2050–2080 and 2070–2099 periods the all-GCM mean shows a flow decrease of 20% (14%) and 26% (17%), respectively, for the A2 (B2) GHG scenarios. However, the uncertainty in the magnitude of simulated future changes remains high. The simulated effect of climate change on minimum monthly flow is proportionally higher than the impact on the annual mean flow.
- Full Text:
- Date Issued: 2006
Installation view: Chale Wote Festival 2018
- Authors: Simbao, Ruth K
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147059 , vital:38589 , https://www.contemporaryand.com/magazines/chale-wote-festival-accra-2018/
- Description: The Chale Wote festival opened on the Day of Re-Membering (20 August), when the Nai Priest poured libations at Brazil House in order to invoke the ancestral spirits. Core events took place on the streets and at various public spaces in James Town from 25 – 26 August. A number of artists including Kiffouly Youchaou, Kresiah Mukwazhi, Va-Bene Elikem Fiatsi (crazinisT artisT), Charlotte Brathwaite, Percy Nii Nortey and the Ubulungiswa/Justice collective created works inside Ussher Fort and James Fort, which were built as slave forts by the Dutch and the British.
- Full Text:
- Date Issued: 2018
Introduction to Psychology 2: PSY 121F
- Authors: Kheswa, J G , Van Niekerk, R
- Date: 2011-05
- Language: English
- Type: Examination paper
- Identifier: vital:18037 , http://hdl.handle.net/10353/d1010621
- Description: Introduction to Psychology 2: PSY 121F, degree examination May/June 2011.
- Full Text: false
- Date Issued: 2011-05
Language and learning science in South Africa
- Authors: Probyn, Margie J
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:7023 , http://hdl.handle.net/10962/d1007204 , http://dx.doi.org/10.2167/le554.0
- Description: South Africa is a multilingual country with 11 official languages. However, English dominates as the language of access and power and although the Language-in- Education Policy (1997) recommends school language policies that will promote additive bilingualism and the use of learners' home languages as languages of learning and teaching, there has been little implementation of these recommendations by schools. This is despite the fact that the majority of learners do not have the necessary English language proficiency to successfully engage with the curriculum and that teachers frequently are obliged to resort to using the learners' home language to mediate understanding. This research investigates the classroom language practices of six Grade 8 science teachers, teaching science through the medium of English where they and their learners share a common home language, Xhosa. Teachers' lessons were videotaped, transcribed and analysed for the opportunities they offered learners for language development and conceptual challenge. The purpose of the research is to better understand the teachers' perceptions and problems and to be able to draw on examples of good practice, to inform teacher training and to develop a coherent bilingual approach for teaching science through the medium of English as an additional language.
- Full Text:
- Date Issued: 2006
Microbial monitoring of surface water in South Africa: an overview
- Authors: Luyt, Catherine D , Tandlich, Roman , Muller, Wilhelmine J , Wilhelmi, Brendan S
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71636 , vital:29927 , https://doi.org/10.3390/ijerph9082669
- Description: Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18.
- Full Text:
- Date Issued: 2012
Microplastic leachates induce species-specific trait strengthening in intertidal mussels:
- Authors: Seuront, Laurent , Nicastro, Katy , McQuaid, Christopher D , Zardi, Gerardo I
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158200 , vital:40162 , https://0-doi.org.wam.seals.ac.za/10.1002/eap.2222. https://doi.org/10.5061/dryad.905qftthq
- Description: Plastic pollution is ubiquitous with increasing recognition of its direct effects on species’ fitness. Little is known, however, about its more subtle effects, including the influence of plastic pollution on the morphological, functional and behavioural traits of organisms that are central to their ability to withstand disturbances. Among the least obvious but most pernicious forms of plastic-associated pollution are the chemicals that leach from microplastics. Here, we investigate how such leachates influence species’ traits by assessing functional trait compensation across four species of intertidal mussels, through investigations of byssal thread production, movement and aggregation behaviour for mussels held in natural seawater or seawater contaminated by microplastic leachates.
- Full Text:
- Date Issued: 2020
New Unity Movement Presidential Address
- Date: 2005-04
- Subjects: Government, Resistance to -- South Africa , South Africa -- History -- 20th century , South Africa -- Politics and government
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10948/32590 , vital:32138 , Bulk File 7
- Description: Presidential Addresses were delivered at each Annual conference of the New Unity Movement. This collection, though incomplete, has 18 items ranging from 1989 to 2013.
- Full Text: false
- Date Issued: 2005-04
New Unity Movement Presidential Address
- Date: 1998-12
- Subjects: Government, Resistance to -- South Africa , South Africa -- History -- 20th century , South Africa -- Politics and government
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10948/32476 , vital:32109 , Bulk File 7
- Description: Presidential Addresses were delivered at each Annual conference of the New Unity Movement. This collection, though incomplete, has 18 items ranging from 1989 to 2013.
- Full Text: false
- Date Issued: 1998-12
NUM Education strategic plan
- Authors: NUM
- Date: 2002-2005
- Subjects: NUM
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/113988 , vital:33867
- Description: The Education Department believes it is important that when assembling a strategic education plan for the next three years, a thorough discussion needs to take place within the Union as a whole about the context that we find ourselves in, and the challenges, which emerge, for our members. What follows are the observations of the Education Department informed by the Unions Ten Year plan and other policy engagements. It is not an exhaustive survey that is offered here, but what are considered key points.
- Full Text:
- Date Issued: 2002-2005
NUM Education strategic plan
- Authors: NUM
- Date: 2001
- Subjects: Uncatalogued
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/106445 , vital:32652
- Description: First we need to ask the obvious question, what is the purpose of a trade union education strategic plan? The answer is as follows,To enable the union to locate its educational concerns and plan its responses with due regard to available resources, and capacity. To ensure that there is a reference point for a thorough on-going assessment of progress. To help articulate a vision for the unions education which inspires and motivates all those concerned. This is critical to the long-term success of our union. Assessing and adopting strategic options requires a vision to help us locate and then analyse both external and internal conditions. It helps us to formulate manageable and realistic strategies to achieve agreed objectives. It helps us to implement our plans with a clear appreciation of our true capacity and to measure outcomes accurately
- Full Text:
- Date Issued: 2001
Preferential fuzzy sets: a key to voting patterns
- Authors: Murali, V
- Date: 2008-04-15
- Language: English
- Type: Text
- Identifier: vital:579 , http://hdl.handle.net/10962/d1012406
- Description: There is a one-to-one correspondence between ordered partitions and kernels of fuzzy subsets under a natural equivalence relation on them called preferential equality, on any n-element set Xn. We discuss some aspects of this correspondence with respect to counting voter’s choice or preference through the notions of Flags, Keychains and Pinned-flags.
- Full Text:
- Date Issued: 2008-04-15
Privilege, solidarity and social justice struggles in South Africa: a view from Grahamstown
- Authors: Matthews, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142270 , vital:38064 , DOI:10.1353/trn.2015.0016
- Description: The last decade has seen a significant increase in the number and prominence of social movements in South Africa. Many of these movements are supported by relatively privileged individuals who are not themselves victims of the injustices the movements oppose. In this paper, I draw out some of the possibilities and limitations of the role of privileged individuals in supporting social movements struggling for social justice, looking particularly at the role of students in supporting such movements. The paper is based on research on the relationship between one such movement, the Unemployed People’s Movement (UPM), and a student organisation, the Students for Social Justice (SSJ), both of which are based in Grahamstown, South Africa. While acknowledging that privileged supporters of such movements can play a constructive role in social justice struggles, I use the experiences of the UPM and SSJ to explore some of the tensions that are likely to emerge and that need to be addressed when the relatively privileged participate in popular struggles. In particular, I discuss the likely difficulties privileged supporters will experience in bridging social divides and in contributing meaningfully to the theorisation of popular struggles.
- Full Text:
- Date Issued: 2015