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The effects of load and gradient on hand force responses during dynamic pushing and pulling tasks

- Bennett, Anthea I, Desai, Sheena D, Todd, Andrew I, Freeland, H

Authors: Bennett, Anthea I , Desai, Sheena D , Todd, Andrew I , Freeland, H
Date: 2008
Language: English
Type: Article
Identifier: vital:6757 , http://hdl.handle.net/10962/d1009459
Description: The limited attention afforded to push/pull activities and the motion phases (initial, sustained and ending) characteristic of these tasks has prompted a research focus in this area. The present study examined biomechanical responses in the form of hand forces during dynamic submaximal trolley pushing and pulling. Participants pushed/pulled loads of 100, 200 and 300 kg on the level (determining impact of load) or pushed 100 kg along a 12° ramp (uphill and downhill- determining impact of gradient). During level exertions significant differences (p<0.05) in hand forces occurred between loads of 100 and 200 kg, and 100 and 300 kg for initial and sustained forces but not ending forces. Values were similar for pushing and pulling at respective loads and motion phases. Strong correlations indicate that initial forces can be used to accurately estimate sustained and ending forces. Importantly, correct technique is essential in force reduction. Forces were highest during uphill initial and sustained phases and the downhill sustained phase. For the initial phase, the forces were highest during uphill pushing (86.5 ± 25.73 N); for the sustained phase, there was no difference between uphill and downhill forces but level forces were significantly lower (18.19 ± 8.09 N) than either of the other two conditions; for the ending phase, the highest forces were produced during downhill pushing (-53.34 ± 13.65N). As sustained forces equaled or exceeded initial forces for uphill and downhill efforts, consideration of sustained forces may be appropriate in determining the inherent potential risk of graded pushing.
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Date Issued: 2008

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The importance of phytoplankton size in mediating trophic interactions within the plankton of a southern African estuary

- Froneman, P William

Authors: Froneman, P William
Date: 2006
Language: English
Type: text , Article
Identifier: vital:6928 , http://hdl.handle.net/10962/d1011944
Description: The influence of the phytoplankton size composition in mediating the trophic interactions between the bacteria, phytoplankton, microheterotrophs (<200 μm) and mesozooplankton (>200 μm) was investigated on three occasions in a warm temperate, temporarily open/closed estuary situated along the southern African coastline. Results of the investigation indicated that the microheterotrophs represented the most important consumers of bacteria and chlorophyll (chl)-a <5.0 μm. The low impact of the mesozooplankton on the bacteria and chl-a <5.0 μm during the study appeared to be related to the inability of the larger zooplankton to feed efficiently on small particles. During those periods when total chl-a concentration was dominated by picophytoplankton (<2.0 μm) and microphytoplankton (>20 μm), mesozooplankton were unable to feed efficiently on the chl-a due to feeding constraints. In response to the unfavorable size structure of the phytoplankton assemblages, mesozooplankton appeared to consume the microheterotrophs. The negative impact of the mesozooplankton on the microheterotrophs resulted in a decrease in the impact of these organisms on the bacteria and the chl-a <5.0 μm. This result is consistent with the predator-prey cascades. On the other hand, when the total chl-a was dominated by nanophytoplankton (2–20 μm), mesozooplankton were able to feed directly on the phytoplankton. Results of the study indicate that size structure of the phytoplankton assemblages within estuaries plays an important role in mediating the trophic interactions between the various components of the plankton food web.
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Date Issued: 2006

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The largest volcanic eruptions on Earth

- Bryan, Scott E, Peate, Ingrid Ukstins, Peate, David W, Self, Stephen, Jerram, Dougal A, Mawby, Michael R, Marsh, Julian S, Miller, Jodie A

Authors: Bryan, Scott E , Peate, Ingrid Ukstins , Peate, David W , Self, Stephen , Jerram, Dougal A , Mawby, Michael R , Marsh, Julian S , Miller, Jodie A
Date: 2010
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/132887 , vital:36902 , https://doi.org/10.1016/j.earscirev.2010.07.001
Description: Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km3 dense rock equivalent) and large-magnitude (> M8) eruptions produce really extensive (104–105 km2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs.
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Date Issued: 2010

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The Malarial Exported PFA0660w Is an Hsp40 Co-Chaperone of PfHsp70-x

- Daniyan, Michael O, Boshoff, Aileen, Prinsloo, Earl, Pesce, Eva-Rachele, Blatch, Gregory L

Authors: Daniyan, Michael O , Boshoff, Aileen , Prinsloo, Earl , Pesce, Eva-Rachele , Blatch, Gregory L
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66098 , vital:28901 , https://doi.org/10.1371/journal.pone.0148517
Description: publisher version , Plasmodium falciparum, the human pathogen responsible for the most dangerous malaria infection, survives and develops in mature erythrocytes through the export of proteins needed for remodelling of the host cell. Molecular chaperones of the heat shock protein (Hsp) family are prominent members of the exportome, including a number of Hsp40s and a Hsp70. PFA0660w, a type II Hsp40, has been shown to be exported and possibly form a complex with PfHsp70-x in the infected erythrocyte cytosol. However, the chaperone properties of PFA0660w and its interaction with human and parasite Hsp70s are yet to be investigated. Recombinant PFA0660w was found to exist as a monomer in solution, and was able to significantly stimulate the ATPase activity of PfHsp70-x but not that of a second plasmodial Hsp70 (PfHsp70-1) or a human Hsp70 (HSPA1A), indicating a potential specific functional partnership with PfHsp70-x. Protein binding studies in the presence and absence of ATP suggested that the interaction of PFA0660w with PfHsp70-x most likely represented a co-chaperone/chaperone interaction. Also, PFA0660w alone produced a concentration-dependent suppression of rhodanese aggregation, demonstrating its chaperone properties. Overall, we have provided the first biochemical evidence for the possible role of PFA0660w as a chaperone and as co-chaperone of PfHsp70-x. We propose that these chaperones boost the chaperone power of the infected erythrocyte, enabling successful protein trafficking and folding, and thereby making a fundamental contribution to the pathology of malaria. , This work was supported by grants from the National Research Foundation (NRF) and Medical Research Council (MRC) of South Africa. The ProteOn XPR36 IAS was purchased from a National Nanotechnology Equipment Programme grant from the Department of Science and Technology and the NRF of South Africa. Michael O. Daniyan was a recipient of the Education Trust Fund (ETF) Academic Staff Training and Development (AST and D) scholarship of Obafemi Awolowo University, Ile-Ife, Nigeria and a Rhodes University Council research bursary
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Date Issued: 2016

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The modern University's response to manpower needs of a developing community

- Henderson, Derek Scott

Authors: Henderson, Derek Scott
Date: 1980
Language: English
Type: text
Identifier: vital:7411 , http://hdl.handle.net/10962/d1018288
Description: In the intellectual tradition which we have inherited in South Africa the university as an institution is predated perhaps only by the Catholic Church. From their very beginnings universities have regarded knowledge, advanced knowledge, its preservation, extension and transmission as their very reason for existence. Modernity, if it implies a serious departure from that tradition, cannot be held as a virtue in a university. A modern university is therefore one that exists in modern times, is in tune with the intellectual needs of those times, and which adapts, without imperilling, its centuries-old outlook towards knowledge. A modern university, most emphatically, is not one which cuts itself off from its age-old intellectual roots. An institution which does so is not a modern university it in fact ceases to be a university at all.
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Date Issued: 1980

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The palladacycle, AJ-5, exhibits anti-tumour and anti-cancer stem cell activity in breast cancer cells:

- Aliwaini, Saeb, Peres, Jade, Kröger, Wendy L, Blanckenberg, Angelique, de la Mare, Jo-Anne, Edkins, Adrienne L, Mapolie, Selwyn, Prince, Sharon

Authors: Aliwaini, Saeb , Peres, Jade , Kröger, Wendy L , Blanckenberg, Angelique , de la Mare, Jo-Anne , Edkins, Adrienne L , Mapolie, Selwyn , Prince, Sharon
Date: 2015
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/164874 , vital:41180 , DOI: 10.1016/j.canlet.2014.11.027
Description: Breast cancer is the most common malignancy amongst women worldwide but despite enormous efforts to address this problem, there is still limited success with most of the current therapeutic strategies. The current study describes the anti-cancer activity of a binuclear palladacycle complex (AJ-5) in oestrogen receptor positive (MCF7) and oestrogen receptor negative (MDA-MB-231) breast cancer cells as well as human breast cancer stem cells. AJ-5 is shown to induce DNA double strand breaks leading to intrinsic and extrinsic apoptosis and autophagy cell death pathways which are mediated by the p38 MAP kinase. This study provides evidence that AJ-5 is potentially an effective compound in the treatment of breast cancer.
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Date Issued: 2015

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The relevance of (South African) Renaissance studies

- Wright, Laurence

Authors: Wright, Laurence
Date: 2005
Language: English
Type: text , article
Identifier: vital:7055 , http://hdl.handle.net/10962/d1007416 , https://www.ajol.info/index.php/sisa/article/view/40550
Description: preprint , This paper is part of a longer piece devoted to the elucidation of two related propositions. The first is that in South Africa the humanities in general, and Renaissance Studies in particular, are stymied by a lack of strategic thinking from those in the academy. The second is that the humanities, and Renaissance Studies, and Shakespeare, are valid and needed in this country, possibly as never before. This paper tackles the latter question, the challenge of intrinsic relevance. What possible bearing have art and literature, politics and religion, customs and technologies developed 10,000 kilometres away and nearly half a millennium ago to do with South Africa in the 21st century? I steal up on the main issue by outlining an abbreviated rhetoric of relevance, establishing a framework within which intrinsic relevance can be conceptualised for Renaissance Studies today.
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Date Issued: 2005

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Thermoluminescence of SrAl2O4: Eu2+, Dy3+: kinetic analysis of a composite-peak

- Chithambo, Makaiko L, Wako, A H, Finch, A A

Authors: Chithambo, Makaiko L , Wako, A H , Finch, A A
Date: 2017
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124157 , vital:35571 , https://doi.org/10.1016/j.radmeas.2016.12.009
Description: The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2+,Dy3+ is reported. The glow-curve is dominated by an apparently-single peak. It has been demonstrated using a number of tests including partial dynamic-heating, isothermal heating, phosphorescence and, the effect of fading, that the peak and the glow-curve consists of a set of closely-spaced peaks. In view of the peak being complex, its first few components were abstracted and analysed and for comparison, the peak was also analysed assuming it is genuinely single.
Full Text: false
Date Issued: 2017

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Thermoluminescence of the main peak in SrAl2O4: Eu2+, Dy3+: spectral and kinetics features of secondary emission detected in the ultra-violet region

- Chithambo, Makaiko L

Authors: Chithambo, Makaiko L
Date: 2017
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124197 , vital:35575 , https://doi.org/10.1016/j.radmeas.2016.12.001
Description: We report the thermoluminescence of SrAl2O4:Eu2+,Dy3+ measured in the ultra-violet region of the spectrum between 300 and 400 nm. Complementary measurements of X-ray excited optical luminescence confirm emission bands of stimulated luminescence in this region. As a further test, optically stimulated luminescence was also measured in this region. The glow curve measured at 1 °C s−1 following irradiation to various doses appears simple and single but is in reality a collection of several components. This was shown by results from the Tm-Tstop method on both ends of the peak, application of thermal cleaning beyond the peak maximum as well as the dependence of the peak on fading. The latter shows that new peaks appear as preceding ones fade. Kinetic analysis of some of the main peaks was carried out giving an activation energy of 0.6 eV. The implication of the results on measurement of phosphorescence, interpretation of dose response and fading is discussed.
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Date Issued: 2017

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Topographic thresholds in gully development on the hillslopes of communal areas in Ngqushwa Local Municipality, Eastern Cape, South Africa

- Kakembo, V, Xanga, W W, Rowntree, Kate M

Authors: Kakembo, V , Xanga, W W , Rowntree, Kate M
Date: 2009
Language: English
Type: Article
Identifier: vital:6691 , http://hdl.handle.net/10962/d1006726
Description: The relationships between the spatial distribution of gully erosion and topographic thresholds in the form of slope angle, position and configuration, as well as land use change in the form of abandoned lands were examined in several affected catchments of the Eastern Cape Province, South Africa. Land use and permanent gullies were mapped, digitized from orthophoto maps in Arc/info 3.5.2 GIS and converted to shapefiles using ArcView 3.2 GIS. Relationships between the mapped phenomena and topographic variables were sought using a Digital Elevation Model (DEM) in Idrisi Kilimanjaro GIS. A comparison between areas with a high potential for gullying and actual gully erosion was made using the Stream Power Index (SPI) as a surrogate for critical flow shear stress. Field surveys were also conducted to assess the present condition of the gullied sites as well as to validate DEM derivations. Seventy five percent of the gullied area was noted to lie on abandoned lands. A predominance of gullying in concave bottom lands was also identified. The SPI values highlighted a distinct preferential topographic zone for gully location. A conceptual model depicting the interaction between land use and topographic parameters to induce gully erosion was developed. This should assist local authorities to develop a policy regarding management of abandoned lands.
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Date Issued: 2009

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Trans-oceanic and endemic origins of the small minnow mayflies (Ephemeroptera, Baetidae) of Madagascar

- Monaghan, Michael T, Gattolliat, Jean-Luc, Sartori, Michel, Elouard, Jean-Marc, James, Helen, Derleth, Pascale, Glaizot, Olivier, De Moor, Ferdy C, Vogler, Alfried P

Authors: Monaghan, Michael T , Gattolliat, Jean-Luc , Sartori, Michel , Elouard, Jean-Marc , James, Helen , Derleth, Pascale , Glaizot, Olivier , De Moor, Ferdy C , Vogler, Alfried P
Date: 2005
Language: English
Type: Article
Identifier: vital:7008 , http://hdl.handle.net/10962/d1008386
Description: We investigated the relative importance of dispersal and vicariance in forming the Madagascar insect fauna, sequencing approximately 2300bp from three rRNA gene regions to investigate the phylogeny of Afrotropical small minnow mayflies (Ephemeroptera: Baetidae). Six lineages contained trans-oceanic sister taxa, and variation in genetic divergence between sister taxa revealed relationships that range from very recent dispersal to ancient vicariance. Dispersal was most recent and frequent in species that spend the larval stage in standing water, adding to evidence that these evolutionarily unstable habitats may select for ecological traits that increase dispersal in insects. Ancestral state likelihood analysis suggested at least one Afrotropical lineage had its origin in Madagascar, demonstrating that unidirectional dispersal from a continental source may be too simplistic. We conclude that the Malagasy mayfly fauna should be considered in a biogeographical context that extends beyond Madagascar itself, encompassing trans-oceanic dispersal within multiple lineages.
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Date Issued: 2005

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Transcending objectifications and dualisms: farm workers and civil society in contemporary Zimbabwe

- Sadomba, Zvakanyorwa W, Helliker, Kirk D

Authors: Sadomba, Zvakanyorwa W , Helliker, Kirk D
Date: 2010
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/71242 , vital:29822 , https://doi.org/10.1177/0021909609357417
Description: In the academic literature, civil society is often conceptualized in terms of objectifications and subject—object dichotomies. This is the case with regard to both social movements and non-governmental organizations. This article seeks to transcend such argumentation by providing ‘thick descriptions’ of the agency of farm workers and civil society in the context of land reform in contemporary Zimbabwe. We examine a land-based social movement (and the role of farm workers within it) and the involvement of a particular non-governmental organization in farm worker livelihoods. On this basis, we offer a re-formulation of civil society as a social field marked by ambivalences and tensions.
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Date Issued: 2010

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