Showing items 24581 - 24600 of 66275

Ostrich calpastatin purification and partial characterization of the liver inhibitor

- Roman, Henry James

  • Authors: Roman, Henry James
  • Date: 2000
  • Subjects: Calpastatin , Protease inhibitors , Ion exchange chromatography , Ostriches
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:11090 , http://hdl.handle.net/10948/d1015522
  • Description: The isolation and purification of calpastatin from ostrich liver is presented, along with its physicochemical and kinetic properties. By using extraction from liver, ion-exchange chromatography on DEAE-Toyopearl, heating to 90 °C for 10 min and rechromatography on Toyopearl Super-Q 650 S, ostrich calpastatin was isolated and purified from ostrich liver. The purified intact calpastatin showed homogeneity on SDS-PAGE (Mr of 105.6 K). Amino acid analysis showed that ostrich calpastatin resembled that of rabbit liver and human erythrocyte calpastatin. An N-terminal sequence could not be obtained because the N-terminus was found to be blocked by an as yet unknown amino acid residue. The Mr values of degradative forms of ostrich liver calpastatin were determined to be 56 K and 90 K. By using PAG-IEF the pI of the intact form was determined to be 5.1. Ostrich liver calpastatin behaved characteristically like other calpastatins during kinetic analysis. Calpastatin inhibited calpain from pH 6 to 9 and was found to be unaffected by temperatures as high as 100 °C. Calpastatin also inhibited calpain activity at Ca2+ concentrations ranging from 1 to 10 mM. The inhibitor was shown to be phosphorylated because after incubation with alkaline phosphatase there was a decrease in inhibitory activity. No inhibitory effects were detected against other proteases such as chymotrypsin and trypsin, with both proteases inactivating calpastatin completely. Ostrich liver calpain was shown to have a pH optimum of 7.5 and a temperature optimum of 30 °C. In terms of its thermodynamic properties it resembled that of other ostrich proteases; DH, DS and DG being 47.07 kJ/mol, -91.1 J/mol/K and 74.237 kJ/mol, respectively. Ostrich liver calpain showed a Km of 0.14 % (w/v). The enzyme was active at both milli- and micro-molar concentrations of Ca2+. Ostrich liver calpastatin showed many physical, chemical and kinetic properties similar to those of other known calpastatins.
  • Full Text: false
  • Date Issued: 2000

Outsourcing for competitive advantage : an evaluation of an owner driver proposition in a South African removals company

- Coleman, Belinda

  • Authors: Coleman, Belinda
  • Date: 2000
  • Subjects: Contracting out -- South Africa , Storage and removal trade -- Subcontracting -- South Africa , Trucking -- South Africa , Benchmarking (Management) -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:11002 , http://hdl.handle.net/10948/d1015540
  • Description: The aim of the research was to assess what competitive advantage a Removals company could expect to gain by outsourcing its driver function to owner drivers. An extensive literature review identified key outsourcing issues. The literature was related to a case study of Stuttaford Van Lines (SVL), a company that is experiencing problems with its current independent contractor driver arrangements and that needs to review its outsourcing decision. In order to learn from best practice in the field of outsourcing to owner drivers, a benchmarking exercise was undertaken at South African Breweries (SAB). The benchmarking exercise identified six key issues that contributed to the success of the SAB owner driver scheme. These points, together with others identified from the literature, were integrated into a recommended outsourcing implementation process for SVL. The research found that it is possible for SVL to outsource the driver function to owner drivers and that such a scheme can be expected to improve customer service levels. The success of the scheme will depend on the selection of the drivers and how effectively it is managed. It was found that it would not be profitable for SVL to outsource to owner drivers using the compensation model proposed. Cost reduction is however only one of the factors to consider in an outsourcing decision.
  • Full Text:
  • Date Issued: 2000

Palynology and palaeo-environment of Pleistocene hyaena coprolites from an open-air site at Oyster Bay, Eastern Cape coast, South Africa

- Carrion, J S, Brink, J S, Scott, Lucy E P, Binneman, J N F

  • Authors: Carrion, J S , Brink, J S , Scott, Lucy E P , Binneman, J N F
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:7000 , http://hdl.handle.net/10962/d1008357
  • Description: Hyaena coprolites in a soil horizon at Oyster Bay, Eastern Cape coast, South Africa, were found associated with abundant, early Last Glacial vertebrate faunal remains that were apparently accumulated by brown hyaenas and prehistoric humans. Artefacts of the Howieson's Poort sub-stage of the Middle Stone Age occur in the same soil. Although direct association between the different finds cannot be demonstrated, there is evidence to suggest that they are broadly contemporaneous. Pollen assemblages in the coprolites were dominated by Myrica and, to a lesser extent, Stoebe-Elytropappus type and Poaceae. Comparison with the modern pollen spectrum suggests that the past environment differed markedly from the current. The presence of Stoebe-Elytropappus, in particular, is considered to indicate a displacement of vegetation zones to lower altitudes. Both fossil pollen and fauna suggest a landscape with a complex mosaic of vegetation indicative of overall cooler, more inland conditions than today.
  • Full Text: false
  • Date Issued: 2000

Patterns of belief in Bushman creation tales: an interpretive study relating to /Xam, Maluti, and Zu/'oasi sources

- Howard, Nadine B

  • Authors: Howard, Nadine B
  • Date: 2000
  • Subjects: South Africa , Creation -- Mythology , Spirituality -- Africa , San (African people) -- Religion , San (African people) -- Folklore
  • Language: English
  • Type: Text
  • Identifier: vital:549 , http://hdl.handle.net/10962/d1019978 , Donated by Geoffrey Howard, 2010.
  • Description: “Patterns of Belief in Bushman Creation Tales” regard /Xam, Maluti, and Zu/’oasi mythology. The study divides into three sections. The Early Period of Conceptual Unity concerns creation of the eland, a symbolic antelope. All beings are animal-persons of the early race. The /Xam deity /Kaggen creates and secretly cares for an eland to whom he feeds honey. The family, missing honey, sends Mongoose to spy on /Kaggen. He sees the eland and informs his father who kills it without Kaggen’s knowledge. Kaggen weeps bitterly. Elsewhere, when Cagn’s away Maluti sons hunt and discover an unknown creature. They try repeatedly to stab it as it breaks away, but returns to lay down. Finally Gewi kills it. They take meat and blood home, but later see Cagn’s snares and feel afraid. The Transition Period of Conceptual Separation and Restoration follows. Separation of animals and people takes place through re-creation and naming. The former animal-person world passes away. Maluti elands are re-created as Gewi tries to undo his “mischief”. Churning the eland’s blood, it scatters, becoming snakes, then hartebeests. Cagn and his wife help: spinning blood, adding fat from the heart. They produce multitudes of untamed elands. Gewi who “spoilt” them must hunt and kill one, but he fails. Cagn then teaches both sons to hunt. However, his elands are swift, and he will now dwell in their bones. “That day game were given to men to eat,” and the transition to knowing is made. Zu/’oasi animal-persons journey to the fire of creation; there to be beautifully marked or otherwise distinguished. /Xam antelope await their naming through the eating or drinking of liquid honeys which colour their hides. The Third Section offers an overview of concepts the thesis presents. It also bears the key to unlock a very old mystery. , Intended as a Masters of Arts thesis for the University of Natal, the author was unable to complete the final chapter before her death, and the thesis was never submitted for examination. It was the wish of her husband that her careful study should be brought to light and be made available to other students of this field.
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  • Date Issued: 2000

PBS 2000

- Didier Sourou Awadi aka DJ Awadi (performer, author), Amadou Barry aka Doug E. Tee, Duggy Tee (performer, author), Palm Tree Enter/Africa with P.B.S. Production

Peer group supervision as an adjunct to individual supervision: an investigation of models of learning

- Akhurst, Jacqueline Elizabeth

  • Authors: Akhurst, Jacqueline Elizabeth
  • Date: 2000
  • Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
  • Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
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  • Date Issued: 2000

Perspectives on inter-professional collaboration : mediation

- Tatchell, Dolores

  • Authors: Tatchell, Dolores
  • Date: 2000
  • Subjects: Divorce mediation -- South Africa , Custody of children-- South Africa
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:707 , http://hdl.handle.net/10962/d1006519 , Divorce mediation -- South Africa , Custody of children-- South Africa
  • Description: This research is based on the continuous search for alternatives in dealing with custody and access of minor children in divorcing families. In spite of the Mediation in Certain Divorce Matters Act, 1987, providing for mediation, it did not lead to the widespread implementation of mediation as an alternative form of dispute resolution in divorce matters. The family advocate as provided for in the Act, serves to protect the interest of minor children in disputes. However, custody evaluation is still used to determine the custody of minor children. Custody evaluation comprises an in depth study and assessment of the structure and functioning of the family made by a social worker and written up in the form of an evaluative report which is then submitted to the family advocate. It occurred to the researcher that there had to be better ways of dealing with custody disputes and consequently the damage done by the parents who fight over their children without any regard for the children’s feelings. It was considered an option to find out from the professionals directly involved with divorce and custody disputes why they have not considered alternatives, such as mediation, to resolve the disputes arising out of a divorce. Semi-structured interviews were conducted with five social workers and five attorneys to gain their perspectives on mediation, how the two professions could cooperate to assist divorcing couples and how inter-professional collaboration could be used to promote the use of mediation in East London. The family advocate was identified as a key role player. The possibility of mandatory mediation was raised with recommendations that it be considered. The co-mediation model was raised to enhance inter-professional collaboration. Social workers see their role as mediating custody issues where the attorneys see their role as mediating division of property and assets. Both professions recognize that they have their own unique contribution to make. Both social workers and attorneys have been found to be willing to collaborate with each other to make a mediation service available to divorcing couples
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  • Date Issued: 2000

Petrographic and geochemical constraints on the origin and post-depositional history of the Hotazel iron-manganese deposits, Kalahari Manganese Field, South Africa

- Tsikos, Harilaos

  • Authors: Tsikos, Harilaos
  • Date: 2000
  • Subjects: Manganese ores -- South Africa Manganese ores -- Geology -- South Africa Iron ores -- Geology -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4987 , http://hdl.handle.net/10962/d1005599
  • Description: The giant Palaeoproterozoic manganese deposits of the Kalahari manganese field (KMF), Northern Cape Province, South Mrica, have been a world renowned resource of manganese ore for many decades. In recent years, the mineralogical composition, geochemistry and genesis of these deposits have been the objects of many geological investigations, yet their origin remains contentious up to the present day. A characteristic feature of the Kalahari deposits is the intimate association of manganese ore and iron-formation of the Superior-type, in the form of three discrete sedimentary cycles constituting the Hotazel Formation. This striking lithological association is an almost unique feature on a global scale. From that point of view, the present study is effectively the first attempt to shed light on the origin and post-depositional history of the Hotazel succession, using as prime focus the petrographic and geochemical characteristics ofthe host iron-formation. Petrographic and whole-rock geochemical information of iron-formation from the southern parts of the KMF, suggests that the Hotazel iron-formation is almost identical to other iron-formations of the world of similar age and petrological character. The rock exhibits essentially no high-grade metamorphic or low-temperature alteration effects. Mineralogically, it contains abundant chert, magnetite, subordinate amounts of silicate minerals (greenalite, minnesotaite, stilpnomelane) and appreciable concentrations of carbonate constituents in the form of coexisting calcite and ankerite. Such mineralogical composition is indicative of processes occurring in a diagenetic" to burial (up to very low-greenschist facies) metamorphic environment. Bulk-rock geochemical data point towards a simple composition with Si02, total Fe-oxide and CaO being the chief major oxide components. Whole-rock rare-earth element data suggest that the iron-formation precipitated from a water column with chemical signatures comparable to modern, shallow oceanic seawater. The virtual absence of positive Eu anomalies is a feature that compares well with similar data from Neoproterozoic, glaciogenic iron-formations of the Rapitan type, and suggests but only a dilute hydrothermal signal, poten!ially derived from distal submarine volcanic activity. Carbon and oxygen isotope data from iron-formation and Mn-bearing carbonates as well as overlying ferriferous limestone of the Mooidraai Formation, compare well with the literature. The former exhibit variable depletion relative to seawater in terms of both BC and 180, while the latter have signatures comparable to normal marine bicarbonate. Isotopic variations appear to be related to fluctuations in the amount of co-precipitated marine carbonate, in conjunction with processes of coupled organic matter oxidation - FelMn reduction in the diagenetic environment. Oxygen isotope data from quartz-magnetite-calcite triplets suggest that crystallisation took place under open-system conditions, with magnetite being the most susceptible phase in terms of fluid-rock isotopic exchange. Data also suggest that the calcite-magnetite pair may constitute a more reliable geothermometer than the quartz-magnetite one, mainly due to the interlinked diagenetic histories between calcite and magnetite. Iron-formation from the northern parts of the KMF can by categorised into three main classes, namely pristine, altered and oxidised. Pristine iron-formation is identical to the one seen in the southernmost parts of the field. Altered iron-formation corresponds to a carbonate-free derivative of intense oxidation and leaching processes at the expense ofpristine iron-formation, and contains almost exclusively binary quartz-hematite mixtures. The rock appears to have lost essentially its entire pre-existing carbonate-related components (i.e., Ca, Mg, Sr, most Mn and Ba) and displays residual enrichments in elements such as Cr, Th, V, Ni and Pb, which would have behaved as immobile constituents during low-temperature alteration. The low temperature origin of altered iron-formation is supported by oxygen isotope data from quartz-hematite pairs which indicate that isotopically light hematite would have derived from oxidation of magneftte and other ferroussilicate compounds in the presence of a low-temperature meteoric fluid, while quartz would have remained isotopically unchanged. Occasional occurrences of acmite-hematite assemblages suggest localised metasomatic processes related to the action ofNaCI-rich fluids at the expense of altered iron-formation. The conditions of acmite genesis are very poorly constrained due to the very broad stability limits of the mineral in environments ranging from magmatic to surface-related. Oxidised iron-formation constitutes a distinct rock-type and shares common attributes with both the pristine and the altered iron-formation. The rock contains hematite as an important constituent while the amount of magnetite is substantially reduced. With regard to carbonate nlinerals, calcite contents are clearly very low or absent, having being replaced in most instances by a single, Mgenriched, dolomite/ankerite:type species. Oxidised iron-formation contains somewhat higher amounts of iron and reduced amounts of Sr and Ba relative to pristine iron-formation, whereas enrichments in elements such as Ni, Th, Pb, Cr, and V are seen, similar to altered iron-formation. Oxidised iron-formation appears to have originated from processes of dissolution-mobilisationreprecipitation of solutes derived primarily from leaching that produced altered iron-formation. It is proposed that the Hotazel iron-formation and associated manganese deposits were formed as a result of episodic sea-level fluctuations in a stratified depositional environment that gradually evolved into a shallow carbonate platform. A critical parameter in the development of manganese sediment may include regional climatic patterns related to a glacial event (Makganyene diamictite) prior to deposition of the Hotazel strata. This suggestion draws parallels with processes that are believed to have led to the formation of worldwide iron-formations and associated manganese deposits subsequent to Neoproterozoic episodes of glaciation. Submarine volcanism related to the underlying Ongeluk lavas appears to have had very little (if any) metallogenic significance, while evidence for a sudden rise in the oxygen contents of the atmosphere and ambient waters is lacking. With regard to later alteration processes, combination of geological and geochemical data point towards the potential influence of surface weathering prior to deposition of rocks of the unconformably overlying Olifantshoek Supergroup, possibly coupled with fault- and/or thrustcontrolled fluid-flow and leaching of the Hotazel succession during post-Olifantshoek times.
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  • Date Issued: 2000

Phloem loading in the sucrose-export-defective (SXD-1) mutant maize is limited by callose deposition at plasmodesmata in bundle sheath-vascular parenchyma interface

- Botha, Christiaan E J, Cross, Robin H M, Van Bel, A J E, Peter, Craig I

  • Authors: Botha, Christiaan E J , Cross, Robin H M , Van Bel, A J E , Peter, Craig I
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6503 , http://hdl.handle.net/10962/d1005926
  • Description: Using Lucifer Yellow we have demonstrated that the phloem-loading pathway from the mesophyll to the bundle sheath-vascular parenchyma interface in Zea mays source leaves follows a symplasmic route in small and intermediate vascular bundles in control as well as in the green sections of mutant sucrose-export-defective (SXD-1) plants. In the anthocyanin-rich mutant leaf sections, Lucifer Yellow transport was prohibited along the same path, at the bundle sheath-vascular parenchyma interface in particular. Plasmodesmata at the latter interface in SXD-1 anthocyanin-rich leaf sections appear to be structurally altered through callose deposition at the plasmodesmal orifices. We suggest that a transport bottleneck at the bundle sheath-vascular parenchyma interface is thus orchestrated and regulated through callose formation, preventing symplasmic transport across this important loading interface.
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  • Date Issued: 2000

Photocatalytic properties of neodymium diphthalocyanine towards the transformation of 4-chlorophenol

- Nensala, Ngudiankama, Nyokong, Tebello

  • Authors: Nensala, Ngudiankama , Nyokong, Tebello
  • Date: 2000
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/${Handle} , vital:58491 , xlink:href="https://doi.org/10.1016/S1381-1169(00)00283-1"
  • Description: Photolysis of aqueous solutions of 4-chlorophenol (4-Cp) in the presence of solid neodymium diphthalocyanine ([Pc(−2)NdPc(−2)]−) and oxygen using visible and ultraviolet (UV) radiation resulted in the formation of a number of products. For photolysis in the visible region, phenol, benzoquinone, hydroquinone were observed as intermediates and 4-chlorocatechol (4-CC) as the main product; intermediates similar to those observed for visible photolysis were obtained. Langmuir–Hinshelwood kinetic model was used for treatment of photochemical data.
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  • Date Issued: 2000

Photocatalytic reactions of metal diphthalocyanine complexes

- Nensala, Ngudiankama

  • Authors: Nensala, Ngudiankama
  • Date: 2000
  • Subjects: Metal complexes Electrochemistry Photochemistry Pentachlorophenol
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4328 , http://hdl.handle.net/10962/d1004989
  • Description: Photocatalytic reactions of tin diphthalocyanine, Sn ^IVPc₂ and anionic form of Nd^III, Dy^III, Eu^III, Tm^III and Lu^III diphthalocyanine complexes ( [Pc(-2)Nd^IIIpc(-2)]⁻ , [Pc(-2)Dy^IIIPc(-2)]⁻ , [Pc(-2)Eu^IIIPc(-2)⁻, [Pc(-2)Tm^IIlPc(-2)r and [Pc(-2)LuIIIpc(-2)]⁻ respectively) in the presence of CH₂CI₂, S0₂, pentachlorophenol (PCP), 4-chlorophenol (4-Cp) and thionyl chloride have been studied. Photoreactions involving lanthanide diphthalocyanines, filtered and unfiltered radiations were employed, whereas for photoreactions involving tin diphthalocyanine, only unfiltered radiation was employed. For lanthanide diphthalocyanine complexes, LnPce-, the photosensitization power increases with the decrease of the lanthanide ionic radii, implying that the photocatalytic activity of LnPc₂⁻ complexes is associated with the π-π interaction between both phthalocyanine rings. Thus, LuPc₂⁻ is a better photocatalyst than other lanthanide diphthalocyanine complexes. Photolysis ofSnPc₂ in an acetonitrile/dichloromethane solvent mixture, using unfiltered radiation from a tungsten lamp, results in the one-electron oxidation of this species to [Pc( -2 )Sn(IV)Pc(-1)]⁻. The relative quantum yields for the disappearance of SnPc₂ are in the order of 10⁻¹. The photoreaction of SnPc₂ is preceded by excitation to nπ* excited states, before been ,quenched by CH₂CI₂. The one-electron oxidation species, [Pc(-2)Sn(lV)pc(-1)]⁻ was also formed during the photolysis of SnPc₂ in dichloromethane containing S0₂, and with quantum yields of order of 10⁻³. Visible photolysis of [Pc( -2)Nd^IIIpc(-2)]⁻, [Pc(-2)Dy^IIIPc(-2)]⁻ and [Pc(-2)Lu^IIIpc(-2)]⁻ in N,N. dimethylformamide (DMF)/dichloromethane solvent mixture containing SO₂, results in the formation of the one-electron oxidation species, Pc(-2 )Nd^IIIpc(-1), Pc( -2) Dyi^IIIPc(-1) and Pc(-2)Lu^IIIpc(-1), respectively. The relative quantum yields are in the order of 10². The photoreactions are preceded by population of the excited triplet state,³π-π* [ LnPc₂]⁻ complex, before exchanging an electron with S0₂. The one-electron oxidation species of Dy^III and Lu^III diphthalocyanine complexes have also been formed from visible photolysis of [Pc(-2 )Dy^IIIPc(-2)]⁻and [Pc(-2)Lu^IIIpc(-2)]⁻in acetonitrile containing PCP. The PCP is reductively dechlorinated to tetra- and trichlorophenols. The quantum yields for the photosensitization reactions are in the order of 1 0⁻. Photolysis, using visible radiation from 220 W Quartzline lamp, of an aqueous solution of 4-Cp, saturated with oxygen and containing a suspension of solid [Pc(-2)Nd^IIIpc(-2)]⁻, results in the formation of benzoquinone, hydro quinone and 4-chlorocatechol. The quantum yields for the degradation of 4-Cp are in the order of 10⁻. Langmuir-Hinshelwood kinetic model shows the adsorption of 4-chlorophenol onto solid [Pc(-2)Nd^IIIpc(-2)]⁻. Lanthanide diphthalocyanine complexes ([Pc-2)Nd^IIIpc(-2)]⁻. [Pc(-2)Eu^IIIpc(-2)]⁻, (Pc(-2)Tm^IIIpc( -2)]⁻ and (Pc(-2)Lu^IIIpc(-2)]⁻) undergo one or two-electron oxidation in the presence of thionyl chloride. At low concentrations of SOCI₂(<10⁻⁴ mol dm⁻³) the visible yhotolysis of [Pc(-2 )LnPc(-2)]⁻ complexes result in the one-electron oxidation, giving neutral lanthanide diphthalocyanine species, Pc(-2)Ln^IIIpc(-1). The Pc(-2 )LnPc(-I) species undergoes one-electron photooxidation to [Pc(-I )LnPc( -I)]⁻ in dichloromethane and in the presence of SOC₁₂. At large concentrations of SOC₁₂ (>10⁻² mol dm⁻³), direct two-electron oxidation of the (Pc(-2 )LnPc - 2)]⁻ species to (Pc(-1)LnPc(-1)]⁻ occurs. Spectroelectrochemical behaviours of Sn^IVPc₂ have been also studied. The cyclic voltammetry ofSnPc₂ in CH₂CI₂/TBAP show two reduction couples at -0.56 V and -0.89 V versus saturated calomel electrode (SCE) and one oxidation couple at 0.35 V versus SCE. In DMFITEAP system, the reduction couples are observed at -0.44 V and -0.81 V versus SCE whereas the oxidation couple occurred at 0.43 V versus SCE. The oxidation couple corresponds to [Pc(-2 )Sn^IVPc(-2 )]/[Pc(-2)Sn^IVPc( -I)] . and the reduction couples to [Pc(-2)Sn^IVPc( -2 )]/[Pc(-2 )Sn^IVPc( -3 )]⁻ and [Pc(-2)Snl^IVPc( -3)] ⁻/[Pc(-3 )Sn^IVPc(-3)]²⁻, respectively. The electronic absorption spectra of these reduced and oxidized species are reported.
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  • Date Issued: 2000

Physiological, perceptual and other performance decrements in combat related tasks following prolonged heavy-load marching

- Clark, Lisa Anne

  • Authors: Clark, Lisa Anne
  • Date: 2000
  • Subjects: Performance -- Psychological aspects , Performance standards -- Case studies , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Marching -- Physiological aspects , Soldiers -- Job stress
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5130 , http://hdl.handle.net/10962/d1005209 , Performance -- Psychological aspects , Performance standards -- Case studies , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Marching -- Physiological aspects , Soldiers -- Job stress
  • Description: In response to challenging situations physiological and psychological adaptations result in elevated levels of arousal and when these levels are 'optimal' performance is enhanced. There are however, limitations to the amount of physiological and mental stimulation one can tolerate, with cumulative fatigue effects being the outcome when stressful conditions are imposed on the individual over an extended period of time. As a result of the extreme physical and cognitive demands placed on military forces while in combat, with soldiers being thrust into battle and required to make critical life-or-death determining decisions followed by appropriate motor responses, the physical and psychological capabilities of the troops are pushed to maximal limits, often resulting in undesirable decrements in physical and mental performance, with consequential human and materiel losses. Thirty-two soldiers participated in a battery of combat-related field and laboratory tests, first under 'normal' conditions with no prior physical activity and then immediately after the participation of an intensive bout of exercise. Physiological and perceptual responses plus standard of performance were measured at various stages of testing. Results of the Rating of Perceived Exertion (RPE), Body Discomfort Scale and heart rate responses revealed significantly higher levels of psychophysical strai,n in response to the strenuous physical activity. Despite these findings, the electromyographic (EMG) activity and efficiency of the combat-related skills were not negatively affected. Rather, nominal improvements in post-activity performance were noted, specifically response time, and this was attributed to elevated arousal and activation as a result of the exercise that was of sufficient duration to enhance arousal without imposing long term cumulative fatigue effects.
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  • Date Issued: 2000

Pineapples in the Eastern Cape: a study of the farm economy and marketing patterns

- Strauss, Conrad Barend

  • Authors: Strauss, Conrad Barend
  • Date: 2000
  • Subjects: Pineapple industry -- South Africa -- Cape of Good Hope Pineapples -- Marketing Agriculture -- Economic aspects -- Eastern Cape
  • Language: English
  • Type: Book , Text
  • Identifier: http://hdl.handle.net/10962/2442 , vital:20291
  • Description: The major objective of this study was to seek a better knowledge and greater understanding of the factors associated with successful pineapple farming in the Eastern Cape Region of the Union of South Africa. As no previous investigation equally representative of commercial pineapple farming patterns in the Eastern Cape has been made, this study can be regarded as a pilot survey of the labour structures, rates of production, combination of enterprises, marketing channels and the suitability of various districts in the region of study for the production of pineapples. In addition, the history of the pineapple in South Africa will be traced briefly, and the position the Union holds as a supplier of pineapples on the world market, will be investigated. The importance of the Eastern Cape as a producer of pineapples in South Africa is well known, but is also unequivocally illustrated by the information in Table 1. According to estimates made by the Division of Economics and Markets for 1955/56 season, no less than 86.5 per cent of the total acreage planted to pineapples in South Africa, was located in this area. Bathurst, East London and Albany, three of the six districts included in the estimate, were particularly prominent. Taken together, they cultivated more than three-quarters of the total area planted to pineapples in the Eastern Cape, and nearly 70 per cent of the total for South Africa. The remaining quarter of the area cultivated in the Eastern Cape was located in the districts of Peddie, Komgha and Alexandria. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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  • Date Issued: 2000

Portfolio of three projects

- Thomas, Lorraine

  • Authors: Thomas, Lorraine
  • Date: 2000
  • Subjects: Educational leadership Organizational change Educational change School management and organization -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1707 , http://hdl.handle.net/10962/d1003590
  • Description: Educational leadership and management is a very wide field of study with interdependent components that should form a chain reaction in order to bring about effective management. This study attempts to investigate planning in schools which is one of the educational leadership and management components or functions. Very little research work has been done on educational planning in the Ciskei schools. This is a shortcoming since the number of secondary schools has mushroomed in the late twentieth century. The Ciskei educational managers and parents need to know and take note of the possible situations in the various schools. This is opportune time, particularly that recent events, i.e. students' demands and strikes, are drawing parents closer to the education of their children. The researcher's experience of inspecting school administration since 1990 has reinforced his conviction that the managerial teams in the Ciskei secondary schools have little knowledge of management, and of planning in particular. Although the investigation is into secondary school administration, it is also pertinent to primary school planning. Management, i.e. school year-planning, control of work, staff development, appointment of teachers, policy governing students and teachers are discussed at length . Joint planning, i.e. a participative or consultative approach, and advance planning, are investigated in relation to the school year-programme. The existence of statutory bodies in the various schools is assessed in order to test parents' involvement in the education of their children. School tours are discussed in relation to students' involvement in the school activities. The analysis of the results highlights areas that require attention, and the recommendations given address the controversial issues in planning in the various schools.
  • Full Text:
  • Date Issued: 2000

Possible crosstalk between signal transduction pathways in the induction of differentiation in HT-29 cells

- Jamie, Hajierah

  • Authors: Jamie, Hajierah
  • Date: 2000
  • Subjects: Cellular signal transduction , Cell differentiation
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:11096 , http://hdl.handle.net/10948/d1019684
  • Description: The investigation into the mechanisms by which compounds such as butyrate induce differentiation in HT-29 cells, is lacking. The colonic carcinoma cell line, HT-29, undergoes differentiation induction in the presence of butyrate and acetoacetate. The Caco-2 cell line spontaneously differentiates on contact inhibition. In this study, a signal transduction pathway involving ATP, cAMP, Ca2+ and the transcriptional factor CREB was investigated following suggestions that the energy state of the cell and diffferentiation are linked. The activity of the MAP kinase cascade, including possible crosstalk that may exist between these pathways was determined. The HT-29 cells were exposed to 5 mM acetoacetate, butyrate, DMSO and propionate. The results of this differentiation induction were compared to Caco-2 and HeLa cells, which are cervical carcinoma cells. It was found that ATP levels are decreased on differentiation induction in HT-29 cells, which, in turn affected the cAMP concentrations. Theoretically, the inducers do not have any effect on PDE 4 activity, and may facilitate the interaction between cAMP and PKA. Influx of Ca2+ into the cells was inhibited to a degree by the inducers, which was possibly overcome by crosstalk between the cAMP and Ca2+ pathways. CREB activation, lineage-specific gene expression, ERK activity and c-myc expression were all dependent on both the inducers used and the cell-type. PKA played a major role in CREB activation in acetoacetate- and butyrate -induced HT-29, Caco-2 and HeLa cells, while a2+/Calmodulin-dependent kinases I/IV may have a secondary role. Alkaline phosphatase expression in HeLa cells was independent of CREB. Evidence that crosstalk between the MAP kinase cascade and the REBactivation pathways exist, was illustrated by increased CREB activation on ERK inhibition in acetoacetate- and butyrate-induced HT-29 and HeLa cells. Also, the role that ERK played in the cells differed with inducer and cell-type. The dependence of cmyc expression on c-jun and c-fos, appeared to be differentiation induction- and celltype specific. Results from this study indicate the potential use of acetoacetate and butyrate as anti-cancer compounds.
  • Full Text:
  • Date Issued: 2000

Pour Mieux t'Aimer

- Priscilia Ngando (lead vocal), Mevio-Mayo, Dany Mouanga, Mouasso (rhythm guitars), Aubin Sandjo, Scorpionkabambay, Mouche Bass (bass guitar), Dany Mouanga, Eric Sefu (solo guitar), Aubin Sandjo, Paul Balong (keyboard), Abel Massock, Fabo Claude, Nono (chorus), Moussa Haissam, Nana Mouskouri, Priscilia Ngando (composers), Aubin Sandjo (drum, percussion, keyboard), Alhadji Mallam Issa (talking drum), Moussa Haissam

Prade

- Beta Simon (performer), Joe (bass), Alfred Young (guitar), Koukougnon, Kalua Dayag (percussion), Amos Stephen (pianos), Brass: Andre Laourou (trumpet), Manu Yodan (sax), Pinheiro Michel (trombone), Astrid, Brou Julie, Liazou Ped (chorus), Soro Mamadou (djembe), Amos Stephen (arranged by), Liazou Ped (duet), Sea Charif, Djedje Honorat

Principals' perceptions of the management of staff appraisal in schools.

- Blaauw, Lindiwe Ellen

  • Authors: Blaauw, Lindiwe Ellen
  • Date: 2000
  • Subjects: Educational evaluation , Teachers -- Rating of
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:2011 , http://hdl.handle.net/10962/d1016080
  • Description: Teacher appraisal has long been a contentious and contested area in educational management. The recent implementation of a new system of appraisal in Eastern Cape Schools has led to renewed interest in the role and management of appraisal. The objective of this study was to investigate principals' perception of the management of staff appraisal. An interpretive paradigm was adopted and the research is a case study of four secondary schools in Port Elizabeth. Two methods were used in collecting data, namely, questionnaires and interviews. The content comparative method was used to analyse the data. The findings of this study showed areas of continuities and discontinuities with the literature and the new document on appraisal. There is a clear understanding among the principals interviewed that staff appraisal should be used to assess individual teacher performance and that it should also be developmental. There is clear support from the principals on the involvement of other stakeholders. They see the process as transformative and participatory. They find it acceptable and are willing to be involved. However, the findings also indicate a lack of readiness on the part of the principals to fully embrace a fully participative and developmental approach to appraisal. On the strength of these findings I conclude the thesis by making recommendations for policy, principals, teachers and for future researchers in the field.
  • Full Text:
  • Date Issued: 2000

PROCEDO - Mouthpiece of the Public and Allied Workers Union of South Africa

- PAWUSA

  • Authors: PAWUSA
  • Date: July 2000
  • Subjects: PAWUSA
  • Language: English, Afrikaans
  • Type: text
  • Identifier: http://hdl.handle.net/10962/113966 , vital:33858
  • Description: Sedert 1992, toe die politieke regskikking van die land begin gebeur het (Goddank), het die rooilig-tyd by ons verbygegaan en, met die verkiesing in 1994, het 'n wonderlike groenlig*tydvak vir ons almal aangebreek. Politiek, en veral party-politiek hierby uitgesluit, sal geen regdenkende mens horn weer wil terugbegeef in die tyd toe demokrasie 'n hoi woord was en die land effektief regeer is deur een magtige kabaal met hordes gedienstige rade, geheime komitees en baantjies-vir-boeties- organisasies nie. Suid-Afrika het destyds, sedert die verkiesing in 1948, progressief 'n minder lekker plek begin raak om in te bly - veral vir party van die groeperings. Dit het hoofsaaklik gebeur, soos dit in Engels gestel word, weens "power corrupts, absolute power corrupts absolutely". Ek sluit nie by hierdie stelling enige spesifieke persone in nie; ek maak slegs in die bree die stelling oor dit waar is van enige situasie. Oor mens maar altyd mens bly en versoekings vo|op is. The previous dispensation was one where, in our public labour environment, one union (or association as it was then known) was closely aligned to the government of the day. They were soon disempowered, simply because it is difficult to disagree if your basic philosophies are similar to those you are supposed to oppose. Eventually, it was not at all strange to find that salary increases where dished out just before an election, simply to be sucked up the following year by inflation,:Which was fairly out of control at the time.
  • Full Text:
  • Date Issued: July 2000

Professional development in environmental education in Zanzibar, Tanzania: distances encountered in a semi-distance learning course

- Heylings, Phillippa Frances

  • Authors: Heylings, Phillippa Frances
  • Date: 2000
  • Subjects: Environmental education -- Tanzania -- Zanzibar Distance education -- Tanzania -- Zanzibar Environmental education Distance education
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1715 , http://hdl.handle.net/10962/d1003598
  • Description: In Zanzibar, in 1995, opportunities for professional development in environmental education were minimal. Yet the demand for professional development was high, especially because of an emphasis on formal qualifications in the country. Credibility was afforded to forms of professional development, aimed at creating more ‘experts’. Ongoing environmental education practice was not achieving its objectives. Into this setting, which was culturally and socio-politically different from the South African context where it was developed, I introduced the Rhodes University Certificate and Gold Fields Participatory Course in Environmental Education (RU/GF); a non-formal, counter-hegemonic course which encouraged critical reflection on the dominant orientations to environmental education practice – including professional development. I used critical ethnographic and action research methods to explore my praxiological interest, the adaptation of the RU/GF curriculum to the Zanzibar context. During the research process, a decision was made to formally accredit the RU/GF course. This decision did not alter the course orientation or the learning process but opened up possibilities for future curriculum development processes. It allowed the students both a formal qualification necessary for status and promotion, and participation in a learning process that challenged the dominant paradigm on professional development and status from within the socio-political context. The research took on a reflexive orientation to research and environmental education. Through a dialectical development of theory, method and results, several important issues emerged. These deal with the ‘distances’ encountered in attempting to address some of the perceived dichotomies in professional development in environmental education through semi-distance learning: the distances between status and learning; the need for career upgrading and the type of learning considered appropriate for professional development in environmental education; the non-quantifiable aims associated with a reflexive orientation to professional development and formal assessment demands for measurable criteria; the democratisation of open-entry courses and the elitism of restricted access; the focus on individual growth and the attainment of a normative grade; theory and practice; and finally distances between learner, text and language. The research supports similar findings emerging from evaluation of the RU/GF course in South Africa and resonates with, and contributes to, issues concerning professional development in environmental education being considered internationally.
  • Full Text:
  • Date Issued: 2000
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