The medicinal chemistry of selected halogenated diketopiperazines CYCLO(CIS-PRO-4F-PRO) and CYCLO(L-PHE-4I-VAL)
- Authors: Dakada, Vuyokazi
- Date: 2019
- Subjects: Medicinal plants , Drug development Cells -- Effect of drugs on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39370 , vital:35221
- Description: Generally, peptides are selective and efficacious compounds; as a result, they are the best candidates for drug discovery and development. Most peptide-based drugs have been approved for clinical use. The 2,5-Diketopiperazines (DKPs), also known as cyclic dipeptides, are simple compounds which come from nature. Many DKPs are extracted from animals and plants. For example, cyclo(Proline(Pro)-Leucine(Leu)), cyclo(Proline-Valine(Val)), cyclo(Proline-Phenylalanine(Phe)) etc. In this study cyclo(cis-Proline(Pro)-4F-Proline(Pro)) and cyclo(L- Phenylalanine(Phe)-4I- Valine (Val)) were synthesized from their linear esters using a method modified by Milne et al. (1992). This method yielded good results. However, cyclo(L-Phe-4I-Val) degraded due to physicochemical stability attributes caused by hygroscopicity and photosensitivity. Quantitative analysis and evaluation of physicochemical properties of each dipeptide was achieved by using scanning electron microscopy, thermal analysis (differential scanning calorimetry and thermogravimetric analysis) and X-ray powder diffraction. To determine the purity of the cyclic dipeptide, high performance liquid chromatography and thin layer chromatography was used. The structural elucidation of the cyclic dipeptides was carried by employing infrared spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy and, molecular modelling and computational chemistry. The aim of this research was to discover possible biological activity of cyclo(cis-Pro-4-F-Pro) and cyclo(L-Phe-4I-Val) with respect to their antimicrobial, anticancer, anti-diabetic and haematological effects. Cyclo(cis-Pro-4Fluoro-Pro) had no inhibitory effect on the antimicrobial strains tested, and cyclo(L-Phe-4Iodo-Val) could not be tested as the compound decomposed.
- Full Text:
- Date Issued: 2019
- Authors: Dakada, Vuyokazi
- Date: 2019
- Subjects: Medicinal plants , Drug development Cells -- Effect of drugs on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39370 , vital:35221
- Description: Generally, peptides are selective and efficacious compounds; as a result, they are the best candidates for drug discovery and development. Most peptide-based drugs have been approved for clinical use. The 2,5-Diketopiperazines (DKPs), also known as cyclic dipeptides, are simple compounds which come from nature. Many DKPs are extracted from animals and plants. For example, cyclo(Proline(Pro)-Leucine(Leu)), cyclo(Proline-Valine(Val)), cyclo(Proline-Phenylalanine(Phe)) etc. In this study cyclo(cis-Proline(Pro)-4F-Proline(Pro)) and cyclo(L- Phenylalanine(Phe)-4I- Valine (Val)) were synthesized from their linear esters using a method modified by Milne et al. (1992). This method yielded good results. However, cyclo(L-Phe-4I-Val) degraded due to physicochemical stability attributes caused by hygroscopicity and photosensitivity. Quantitative analysis and evaluation of physicochemical properties of each dipeptide was achieved by using scanning electron microscopy, thermal analysis (differential scanning calorimetry and thermogravimetric analysis) and X-ray powder diffraction. To determine the purity of the cyclic dipeptide, high performance liquid chromatography and thin layer chromatography was used. The structural elucidation of the cyclic dipeptides was carried by employing infrared spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy and, molecular modelling and computational chemistry. The aim of this research was to discover possible biological activity of cyclo(cis-Pro-4-F-Pro) and cyclo(L-Phe-4I-Val) with respect to their antimicrobial, anticancer, anti-diabetic and haematological effects. Cyclo(cis-Pro-4Fluoro-Pro) had no inhibitory effect on the antimicrobial strains tested, and cyclo(L-Phe-4Iodo-Val) could not be tested as the compound decomposed.
- Full Text:
- Date Issued: 2019
The Moderating Influence of Psychological Empowerment in the relationship between Job Insecurity and Organizational Citizenship Behaviour among the Eastern Cape Department of Health Employees
- Authors: Nwokolo, Echezona E
- Date: 2019
- Subjects: Job security -- South Africa -- Eastern Cape Organizational commitment Employee assistance programs
- Language: English
- Type: Thesis , Doctoral , D.Com (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/13881 , vital:39722
- Description: The unabated focus of many organizations on competition and profitability has amplified the threats of real or anticipated job loss resulting in the feelings of insecurity for employees about their job and future work life. The research investigated the role of psychological empowerment as moderator of the relationship between job insecurity and organizational citizenship behavior among the Eastern Cape Department of Health employees, in Eastern Cape Province of South Africa. The study adopted an exploratory and correlational research design to understand the relationships that exist between the study variables. Respondents were selected using convenience sampling technique, where a sample size of 357 respondents was selected from sample frame of 4847 employees. Seven-point and Five-point likert scale were used to measure the responses. The data analysis methods used include descriptive statistics, regression analysis, ANOVA and Structural Equation Modeling. The reliability, factor analysis and research hypotheses of the research instruments were tested using the aforementioned statistical techniques. The findings reveal a significant negative correlation between job insecurity and Organizational Citizenship Behaviour, a significant positive correlation between psychological empowerment and OCB. It also revealed that job insecurity and psychological empowerment combined account for a significant higher proportion of variance in OCB than any of the two separately, and that significantly and positively moderates the relationship between job insecurity and OCB. Recommendations to promote psychological empowerment in the organization in order to increase organizational citizenship behavior and decrease job insecurity among employees were suggested to leadership of the government departments, organizations and practicing managers.
- Full Text:
- Date Issued: 2019
- Authors: Nwokolo, Echezona E
- Date: 2019
- Subjects: Job security -- South Africa -- Eastern Cape Organizational commitment Employee assistance programs
- Language: English
- Type: Thesis , Doctoral , D.Com (Industrial Psychology)
- Identifier: http://hdl.handle.net/10353/13881 , vital:39722
- Description: The unabated focus of many organizations on competition and profitability has amplified the threats of real or anticipated job loss resulting in the feelings of insecurity for employees about their job and future work life. The research investigated the role of psychological empowerment as moderator of the relationship between job insecurity and organizational citizenship behavior among the Eastern Cape Department of Health employees, in Eastern Cape Province of South Africa. The study adopted an exploratory and correlational research design to understand the relationships that exist between the study variables. Respondents were selected using convenience sampling technique, where a sample size of 357 respondents was selected from sample frame of 4847 employees. Seven-point and Five-point likert scale were used to measure the responses. The data analysis methods used include descriptive statistics, regression analysis, ANOVA and Structural Equation Modeling. The reliability, factor analysis and research hypotheses of the research instruments were tested using the aforementioned statistical techniques. The findings reveal a significant negative correlation between job insecurity and Organizational Citizenship Behaviour, a significant positive correlation between psychological empowerment and OCB. It also revealed that job insecurity and psychological empowerment combined account for a significant higher proportion of variance in OCB than any of the two separately, and that significantly and positively moderates the relationship between job insecurity and OCB. Recommendations to promote psychological empowerment in the organization in order to increase organizational citizenship behavior and decrease job insecurity among employees were suggested to leadership of the government departments, organizations and practicing managers.
- Full Text:
- Date Issued: 2019
The morphological and molecular variation of southern African Nannocharax (Characiformes: Distichodontidae), and its taxonomic implications
- Authors: Smith, Timothy
- Date: 2019
- Subjects: Nannocharax -- Africa, Southern , Distichodontidae -- Africa, Southern , Freshwater fishes -- Africa, Southern , Nannocharax -- Genetics -- Africa, Southern , Distichodontidae -- Genetics -- Africa, Southern , Freshwater fishes -- Genetics -- Africa, Southern
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69212 , vital:29446
- Description: Nannocharax is the most species rich genus in the family Distichodontidae, being currently represented by 41 species. The genus is widely distributed across much of sub-Saharan Africa, with a range extending from the Zambezi ichthyofaunal province in the south to the Nilo-Sudan ichthyofaunal province in the north. In southern Africa, the genus is currently represented by four species, Nannocharax dageti Jerep, Vari, & Vreven, 2014, N. machadoi (Poll, 1967), N. macropterus Pellegrin, 1926, and N. multifasciatus Boulenger, 1923. Each of these species exhibit considerable intraspecific pigmentation pattern variation across their respective distribution ranges, suggesting that the current taxonomy possibly underestimates the taxonomic diversity of Nannocharax species in southern Africa. Much pigmentation pattern variation within these southern African species has been observed by both collectors and scientists in the field, prompting an investigation into the extent of this morphological variation as well as what molecular variation may occur as well. The genus displays a high degree of morphological conservatisim, making it difficult to assign external morphological characters as diagnostic. To this end, this study was conducted to determine the extent of diversity of this genus in the region, employing an integrative approach with traditional morphological analysis techniques as well as sequencing the ‘barcoding gene’, cytochrome oxidase I, testing the hypothesis that there is a greater, hidden diversity of this genus in the region than currently recognised. This study aims to identify these potential lineages and accurately map their distributions. Phylogenetic analyses were performed using maximum parsimony, maximum likelihood, and Bayesian inference, using the mitochondrial cytochrome oxidase I gene region. Massive genetic divergence was detected between populations of taxa previously considered to be singular, widely distributed species. The three approaches of phylogenetic inference used in this study yielded trees of comparable overall topology, with the exception of the maximum parsimony tree which indicated additional lineages within the southern African N. multifasciatus group. These analyses revealed four deeply divergent (1.3 – 12.3%) lineages within southern African N. macropterus, as well as two deeply divergent (0.4-14.6%) populations from the Congo ichthyofaunal region, the lineages here named “N. macropterus Congo 1” and “N. macropterus Congo 2”. Within the southern African region, two deeply divergent (10.3%) lineages of N. macropterus were identified from the Okavango River system, identified as “N. macropterus Okavango 2” lineage restricted to the Cuito-Canavale tributary, and “N. macropterus Okavango 1” distributed throughout the remainder of the Okavango system. “N. macropterus Okavango 2” shares a closer relationship with the unique lineage from the Kwanza ichthyofaunal region, named N. macropterus “Kwanza”, which itself is deeply divergent from the N. macropterus “Okavango 1”, N. macropterus “Zambezi”, N. macropterus “Congo 1” and N. macropterus “Congo 2” lineages (3.1-14.4%). Principal component analyses (PCA) and discriminant function analyses (DFA) produced overlapping clusters for all identified lineages, with the exception of the N. macropterus “Kwanza” lineage, which in all analyses clustered away from the other lineages. Analysis of variance (ANOVA) and Kruskall-Wallis tests indicated significant differences in means between character traits between lineages, however, overlap in measurements and counts occurred in all instances except between the N. macropterus “Kwanza” and N. macropterus Congo lineages. However the N. macropterus “Kwanza” lineages could be distinguished from the other lineages by generally smaller fin lengths (dorsal fin 19.5%SL vs 20.0-22.1%SL in others; pectoral fin 16.5%SL vs 20.6-21.8%SL in others; pelvic fin 18.3%SL vs 21.3-22.4) and pigmentation pattern differences. The N. macropterus species group displayed extensive pigmentation pattern variation, to the extent that five pattern grades could be used to classify them. These pattern grades, while not specific to river systems, showed patterns similar to that which was seen in the molecular analyses and could be linked to lineages with only minor overlap between them. Three lineages of N. multifasciatus were identified, with two occurring in the southern African region, each corresponding to a river system, being the N. multifasciatus “Zambezi” and N. multifasciatus “Okavango” lineages. This species group displayed shallower divergence between lineages than did the N. macropterus group, at 2.5% genetic distance. Genetic analysis inferred a closer relationship between the N. multifasciatus “Zambezi” and N. multifasciatus “Congo” lineages than with the N. multifasciatus “Okavango” lineage. Morphological PCA and DFA analyses indicated morphological divergence of the N. multifasciatus “Congo” lineage, with generally larger proportional measurements than southern African specimens (body width 12.6%SL vs 9.5-9.7%SL; body depth 26.6%SL vs 21.6-21.9%SL; head width 12.0%SL vs 10.0-10.4%SL). PCA, DFA, and measurements show a near complete overlap between the N. multifasciatus “Okavango” and N. multifasciatus “Zambezi” lineages. Pigmentation pattern variation occurred within this group, but none that could be assigned to a particular lineage. The N. machadoi species group in southern Africa consists of five lineages: N. machadoi “Zambezi 1”, N. machadoi “Zambezi 2”, N. machadoi “Kafue 1”, N. machadoi “Kafue 2”, and N. machadoi “Okavango”. This group displayed shallower genetic divergence between lineages than the other southern African Nannocharax species groups (0.4-1.3%). This shallow genetic divergence is paralleled by near complete morphological overlap, with PCA and DFA producing overlapping clusters, and measurements, meristics, and pigmentation pattern metrics consisting of very similar values for the lineages. These results indicate that what is considered to be “N. macropterus” in southern Africa should not be named as such. The N. macropterus “Zambezi” and the N. macropterus “Okavango 1” lineages, are misidentifications of Nannocharax dageti. Other “N. macropterus” from the southern African region possesses fewer circumpeduncular scales than the true N. macropterus as described by Pellegrin (1926), and require taxonomic re-evaluation, each here being recognised as a unique lineage with species status, here named N. macropterus “Okavango 2” and N. macropterus “Kwanza”. In particular, N. macropterus “Kwanza” displays deep genetic divergence as well as morphological dissimilarity with the other southern African “N. macropterus” groups. Nannocharax fasciolaris and N. monardi are here placed as junior synonyms of N. multifasciatus, owing to vast overlaps in measurements and character counts of these species and N. multifasciatus, which is also known to occur within the same geographical distribution, as well as dubious arguments from the original publications in delineating these species from N. multifasciatus. Therefore, there is insufficient evidence indicating the presence of multiple species originating from the Okavango system, where it is here indicated that only a single lineage of banded, adipose fin-bearing Nannocharax occurs, namely N. multifasciatus “Okavango”.
- Full Text:
- Date Issued: 2019
- Authors: Smith, Timothy
- Date: 2019
- Subjects: Nannocharax -- Africa, Southern , Distichodontidae -- Africa, Southern , Freshwater fishes -- Africa, Southern , Nannocharax -- Genetics -- Africa, Southern , Distichodontidae -- Genetics -- Africa, Southern , Freshwater fishes -- Genetics -- Africa, Southern
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69212 , vital:29446
- Description: Nannocharax is the most species rich genus in the family Distichodontidae, being currently represented by 41 species. The genus is widely distributed across much of sub-Saharan Africa, with a range extending from the Zambezi ichthyofaunal province in the south to the Nilo-Sudan ichthyofaunal province in the north. In southern Africa, the genus is currently represented by four species, Nannocharax dageti Jerep, Vari, & Vreven, 2014, N. machadoi (Poll, 1967), N. macropterus Pellegrin, 1926, and N. multifasciatus Boulenger, 1923. Each of these species exhibit considerable intraspecific pigmentation pattern variation across their respective distribution ranges, suggesting that the current taxonomy possibly underestimates the taxonomic diversity of Nannocharax species in southern Africa. Much pigmentation pattern variation within these southern African species has been observed by both collectors and scientists in the field, prompting an investigation into the extent of this morphological variation as well as what molecular variation may occur as well. The genus displays a high degree of morphological conservatisim, making it difficult to assign external morphological characters as diagnostic. To this end, this study was conducted to determine the extent of diversity of this genus in the region, employing an integrative approach with traditional morphological analysis techniques as well as sequencing the ‘barcoding gene’, cytochrome oxidase I, testing the hypothesis that there is a greater, hidden diversity of this genus in the region than currently recognised. This study aims to identify these potential lineages and accurately map their distributions. Phylogenetic analyses were performed using maximum parsimony, maximum likelihood, and Bayesian inference, using the mitochondrial cytochrome oxidase I gene region. Massive genetic divergence was detected between populations of taxa previously considered to be singular, widely distributed species. The three approaches of phylogenetic inference used in this study yielded trees of comparable overall topology, with the exception of the maximum parsimony tree which indicated additional lineages within the southern African N. multifasciatus group. These analyses revealed four deeply divergent (1.3 – 12.3%) lineages within southern African N. macropterus, as well as two deeply divergent (0.4-14.6%) populations from the Congo ichthyofaunal region, the lineages here named “N. macropterus Congo 1” and “N. macropterus Congo 2”. Within the southern African region, two deeply divergent (10.3%) lineages of N. macropterus were identified from the Okavango River system, identified as “N. macropterus Okavango 2” lineage restricted to the Cuito-Canavale tributary, and “N. macropterus Okavango 1” distributed throughout the remainder of the Okavango system. “N. macropterus Okavango 2” shares a closer relationship with the unique lineage from the Kwanza ichthyofaunal region, named N. macropterus “Kwanza”, which itself is deeply divergent from the N. macropterus “Okavango 1”, N. macropterus “Zambezi”, N. macropterus “Congo 1” and N. macropterus “Congo 2” lineages (3.1-14.4%). Principal component analyses (PCA) and discriminant function analyses (DFA) produced overlapping clusters for all identified lineages, with the exception of the N. macropterus “Kwanza” lineage, which in all analyses clustered away from the other lineages. Analysis of variance (ANOVA) and Kruskall-Wallis tests indicated significant differences in means between character traits between lineages, however, overlap in measurements and counts occurred in all instances except between the N. macropterus “Kwanza” and N. macropterus Congo lineages. However the N. macropterus “Kwanza” lineages could be distinguished from the other lineages by generally smaller fin lengths (dorsal fin 19.5%SL vs 20.0-22.1%SL in others; pectoral fin 16.5%SL vs 20.6-21.8%SL in others; pelvic fin 18.3%SL vs 21.3-22.4) and pigmentation pattern differences. The N. macropterus species group displayed extensive pigmentation pattern variation, to the extent that five pattern grades could be used to classify them. These pattern grades, while not specific to river systems, showed patterns similar to that which was seen in the molecular analyses and could be linked to lineages with only minor overlap between them. Three lineages of N. multifasciatus were identified, with two occurring in the southern African region, each corresponding to a river system, being the N. multifasciatus “Zambezi” and N. multifasciatus “Okavango” lineages. This species group displayed shallower divergence between lineages than did the N. macropterus group, at 2.5% genetic distance. Genetic analysis inferred a closer relationship between the N. multifasciatus “Zambezi” and N. multifasciatus “Congo” lineages than with the N. multifasciatus “Okavango” lineage. Morphological PCA and DFA analyses indicated morphological divergence of the N. multifasciatus “Congo” lineage, with generally larger proportional measurements than southern African specimens (body width 12.6%SL vs 9.5-9.7%SL; body depth 26.6%SL vs 21.6-21.9%SL; head width 12.0%SL vs 10.0-10.4%SL). PCA, DFA, and measurements show a near complete overlap between the N. multifasciatus “Okavango” and N. multifasciatus “Zambezi” lineages. Pigmentation pattern variation occurred within this group, but none that could be assigned to a particular lineage. The N. machadoi species group in southern Africa consists of five lineages: N. machadoi “Zambezi 1”, N. machadoi “Zambezi 2”, N. machadoi “Kafue 1”, N. machadoi “Kafue 2”, and N. machadoi “Okavango”. This group displayed shallower genetic divergence between lineages than the other southern African Nannocharax species groups (0.4-1.3%). This shallow genetic divergence is paralleled by near complete morphological overlap, with PCA and DFA producing overlapping clusters, and measurements, meristics, and pigmentation pattern metrics consisting of very similar values for the lineages. These results indicate that what is considered to be “N. macropterus” in southern Africa should not be named as such. The N. macropterus “Zambezi” and the N. macropterus “Okavango 1” lineages, are misidentifications of Nannocharax dageti. Other “N. macropterus” from the southern African region possesses fewer circumpeduncular scales than the true N. macropterus as described by Pellegrin (1926), and require taxonomic re-evaluation, each here being recognised as a unique lineage with species status, here named N. macropterus “Okavango 2” and N. macropterus “Kwanza”. In particular, N. macropterus “Kwanza” displays deep genetic divergence as well as morphological dissimilarity with the other southern African “N. macropterus” groups. Nannocharax fasciolaris and N. monardi are here placed as junior synonyms of N. multifasciatus, owing to vast overlaps in measurements and character counts of these species and N. multifasciatus, which is also known to occur within the same geographical distribution, as well as dubious arguments from the original publications in delineating these species from N. multifasciatus. Therefore, there is insufficient evidence indicating the presence of multiple species originating from the Okavango system, where it is here indicated that only a single lineage of banded, adipose fin-bearing Nannocharax occurs, namely N. multifasciatus “Okavango”.
- Full Text:
- Date Issued: 2019
The morphological complexity of L1 Arabic-speaking children
- Authors: Issa, Iyad
- Date: 2019
- Subjects: Cognition in children , Reading , Arabic language -- Orthography and spelling , Arabic language -- Orthography and spelling -- Study and teaching , Arabic language -- Study and teaching , Arabic language -- Phonetics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92831 , vital:30754
- Description: Spelling poses a challenge to Arabic-speaking learners due to the complexity of the morphological and orthographic system in Arabic. Arabic morphology has been argued to play a critical role in spelling since its morphological operations are built on a system consisting of a root that is interlocking into different patterns of vowels to form different categories of words. In addition, Arabic orthography is considered to be loyal to the morphographic principle (Ravid, 2012), where morphemes correspond to graphic representation regardless of the pronunciation, especially in the non-vowelized texts. This study made a detailed classification of spelling errors in a word dictation task, based on morphological structures, undertaken by 107 Typically-developing learners (TD) and learners with learning disabiities (LD) attending the same schools. All participants ranged in age from 7 years, 3 months to 15 years, 2 months (grades 2 to 8). The spelling task was made up of 400 common words representing all morphological forms in different conjugations and grammatical classes. The results indicated that learners made three types of errors: errors with respect to the root, errors with respect to the word pattern, and errors with respect to both the root and the word pattern. The results also showed that TD and LD learners follow a similar pattern of complexity even though the LD group produced more errors than the TD group. The results revealed that MA and PA exhibited significant positive regression (b= 9.398, 16.106 respectively) with spelling, indicating that learners with higher scores in PA and MA have higher scores in spelling. The results argued for the crucial contribution that morphological awareness makes towards the general spelling abilities among learners and provide additional evidence for the nonlinear growth of morphological knowedge in spelling. In addition, spelling errors suggested that the spelling process goes in a hierarchical way where words can be accessed and processed either according to the root or according to the stem. Intact verbs are processed according to their root and word pattern. Some weak verb forms, whose radicals undergo modifications, are processed according to their stem, while those whose radicals are fully represented in the spoken word, are processed according to their root and word patterns. Therefore, roots or stems are firstly accessed and attached to basic word patterns (the grapheme without diacritics and affixes). Thereafter, prefixes and, then, suffixes are attached to the word pattern and, finally, diacritics are accessed and attached to the word pattern.
- Full Text:
- Date Issued: 2019
- Authors: Issa, Iyad
- Date: 2019
- Subjects: Cognition in children , Reading , Arabic language -- Orthography and spelling , Arabic language -- Orthography and spelling -- Study and teaching , Arabic language -- Study and teaching , Arabic language -- Phonetics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92831 , vital:30754
- Description: Spelling poses a challenge to Arabic-speaking learners due to the complexity of the morphological and orthographic system in Arabic. Arabic morphology has been argued to play a critical role in spelling since its morphological operations are built on a system consisting of a root that is interlocking into different patterns of vowels to form different categories of words. In addition, Arabic orthography is considered to be loyal to the morphographic principle (Ravid, 2012), where morphemes correspond to graphic representation regardless of the pronunciation, especially in the non-vowelized texts. This study made a detailed classification of spelling errors in a word dictation task, based on morphological structures, undertaken by 107 Typically-developing learners (TD) and learners with learning disabiities (LD) attending the same schools. All participants ranged in age from 7 years, 3 months to 15 years, 2 months (grades 2 to 8). The spelling task was made up of 400 common words representing all morphological forms in different conjugations and grammatical classes. The results indicated that learners made three types of errors: errors with respect to the root, errors with respect to the word pattern, and errors with respect to both the root and the word pattern. The results also showed that TD and LD learners follow a similar pattern of complexity even though the LD group produced more errors than the TD group. The results revealed that MA and PA exhibited significant positive regression (b= 9.398, 16.106 respectively) with spelling, indicating that learners with higher scores in PA and MA have higher scores in spelling. The results argued for the crucial contribution that morphological awareness makes towards the general spelling abilities among learners and provide additional evidence for the nonlinear growth of morphological knowedge in spelling. In addition, spelling errors suggested that the spelling process goes in a hierarchical way where words can be accessed and processed either according to the root or according to the stem. Intact verbs are processed according to their root and word pattern. Some weak verb forms, whose radicals undergo modifications, are processed according to their stem, while those whose radicals are fully represented in the spoken word, are processed according to their root and word patterns. Therefore, roots or stems are firstly accessed and attached to basic word patterns (the grapheme without diacritics and affixes). Thereafter, prefixes and, then, suffixes are attached to the word pattern and, finally, diacritics are accessed and attached to the word pattern.
- Full Text:
- Date Issued: 2019
The morphotactic constraints of verbal extensions in isiXhosa
- Authors: Mkabile, Hlumela
- Date: 2019
- Subjects: Xhosa language -- Grammar
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92849 , vital:30749
- Description: Bantu verbal suffixes, also known as extensions, follow a rather rigid pattern when they attach to the verb. Studies (e.g. Hyman 2002, Good 2005, 2007, among others) have shown that the order followed by these extensions is: Causative, Applicative, Reciprocal, Passive (CARP). Although this pattern is widespread across Bantu, some variations in the ordering of these extensions have been observed in some languages (Kathupa 1991, Simango 1995, Sibanda 2004, among others), which suggests that the template is not as rigid as one might think. This study investigated the morphotactic constraints between four verbal extensions in isiXhosa, the Causative, Applicative, Reciprocal and Passive. It focused on the morphotactics of the transitivising extensions (Causative and Applicative) in the first instance, and morphotactics of the detransitivising extensions (Reciprocal and Passive) in the second instance. The study found that although the co-occurrence of causatives and applicatives is a regular feature in Bantu languages, isiXhosa has restrictions on the co-occurrence of these extensions on some verbs. The study also found that although Causative-Applicative is the expected order the language permits Applicative-Causative in certain contexts. With respect to the detransitivising extensions, the study revealed that there are limited contexts in which these extensions co-occur and, crucially, that these extensions are freely ordered in the language.
- Full Text:
- Date Issued: 2019
- Authors: Mkabile, Hlumela
- Date: 2019
- Subjects: Xhosa language -- Grammar
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92849 , vital:30749
- Description: Bantu verbal suffixes, also known as extensions, follow a rather rigid pattern when they attach to the verb. Studies (e.g. Hyman 2002, Good 2005, 2007, among others) have shown that the order followed by these extensions is: Causative, Applicative, Reciprocal, Passive (CARP). Although this pattern is widespread across Bantu, some variations in the ordering of these extensions have been observed in some languages (Kathupa 1991, Simango 1995, Sibanda 2004, among others), which suggests that the template is not as rigid as one might think. This study investigated the morphotactic constraints between four verbal extensions in isiXhosa, the Causative, Applicative, Reciprocal and Passive. It focused on the morphotactics of the transitivising extensions (Causative and Applicative) in the first instance, and morphotactics of the detransitivising extensions (Reciprocal and Passive) in the second instance. The study found that although the co-occurrence of causatives and applicatives is a regular feature in Bantu languages, isiXhosa has restrictions on the co-occurrence of these extensions on some verbs. The study also found that although Causative-Applicative is the expected order the language permits Applicative-Causative in certain contexts. With respect to the detransitivising extensions, the study revealed that there are limited contexts in which these extensions co-occur and, crucially, that these extensions are freely ordered in the language.
- Full Text:
- Date Issued: 2019
The Neethling Brain Instrument (NBI) as a predictive indicator for leadership branding
- Authors: Buys, Hein
- Date: 2019
- Subjects: Branding (Marketing) , Educational leadership -- Marketing Corporate image Leadership -- South Africa Executive ability
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/37900 , vital:34260
- Description: The purpose of this treatise is to determine whether the Neethling 8-Dimensional Brain Instrument (NBI) can serve as a predictive indicator of leadership brand of individuals. In practice the focus of recruitment is often solely concerned with the person-job fit in so far as hard-skills of the individual applicants are relevant and suitable to the position that must be filled. It is the belief of the researcher in this treatise that a more holistic approach in filling leadership roles most be adopted in order to increase the successful placement of leaders based not only on the person-job fit, but also on the person-team and person-organisation fit. Certain leadership brands are more suitable in certain environments and this must be tested for as part of the recruitment and placement process. This qualitative case study is exploratory in nature and hopes to gain a deeper understanding of predictive capability of the NBI in relation to leadership branding.
- Full Text:
- Date Issued: 2019
- Authors: Buys, Hein
- Date: 2019
- Subjects: Branding (Marketing) , Educational leadership -- Marketing Corporate image Leadership -- South Africa Executive ability
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/37900 , vital:34260
- Description: The purpose of this treatise is to determine whether the Neethling 8-Dimensional Brain Instrument (NBI) can serve as a predictive indicator of leadership brand of individuals. In practice the focus of recruitment is often solely concerned with the person-job fit in so far as hard-skills of the individual applicants are relevant and suitable to the position that must be filled. It is the belief of the researcher in this treatise that a more holistic approach in filling leadership roles most be adopted in order to increase the successful placement of leaders based not only on the person-job fit, but also on the person-team and person-organisation fit. Certain leadership brands are more suitable in certain environments and this must be tested for as part of the recruitment and placement process. This qualitative case study is exploratory in nature and hopes to gain a deeper understanding of predictive capability of the NBI in relation to leadership branding.
- Full Text:
- Date Issued: 2019
The nexus between capital inflows and credit growth in South Africa
- Authors: Davani, Siviwe
- Date: 2019
- Subjects: Capital movements Credit
- Language: English
- Type: Thesis , Masters , MCom (Economics)
- Identifier: http://hdl.handle.net/10353/16885 , vital:40782
- Description: This study examines the effect of capital inflows on credit growth on the South African economy. Capital inflows ease the constraint of the low domestic savings in the domestic economy. The study employed the Structural Vector Auto Regression model to analyse the relationship between the variables of interest. The findings of the study indicate that the two types of capital inflows employed in the study, Foreign Direct Investment and Foreign Portfolio investment have a significant effect on credit growth in the long-run. The results also indicate that there are other important factors such as macroeconomic stability and political stability which have a significant effect of capital inflows into South Africa. Overall, the results revealed that a greater variation of credit growth is explained by GDP. This indicates that there is a link between GDP and FDI and FPI given their link with credit growth. These results also suggest that the foreign capital channel can be another channel which may affect growth in the domestic economy in the event that there are negative innovations which affects capital flows to South Africa. The study thus suggests that policies which ensures macroeconomic stability and political stability should be pursued given their influence on capital inflows into South Africa. Also it’s recommended that the country mobilise domestic resources to ensure sustainable development
- Full Text:
- Date Issued: 2019
- Authors: Davani, Siviwe
- Date: 2019
- Subjects: Capital movements Credit
- Language: English
- Type: Thesis , Masters , MCom (Economics)
- Identifier: http://hdl.handle.net/10353/16885 , vital:40782
- Description: This study examines the effect of capital inflows on credit growth on the South African economy. Capital inflows ease the constraint of the low domestic savings in the domestic economy. The study employed the Structural Vector Auto Regression model to analyse the relationship between the variables of interest. The findings of the study indicate that the two types of capital inflows employed in the study, Foreign Direct Investment and Foreign Portfolio investment have a significant effect on credit growth in the long-run. The results also indicate that there are other important factors such as macroeconomic stability and political stability which have a significant effect of capital inflows into South Africa. Overall, the results revealed that a greater variation of credit growth is explained by GDP. This indicates that there is a link between GDP and FDI and FPI given their link with credit growth. These results also suggest that the foreign capital channel can be another channel which may affect growth in the domestic economy in the event that there are negative innovations which affects capital flows to South Africa. The study thus suggests that policies which ensures macroeconomic stability and political stability should be pursued given their influence on capital inflows into South Africa. Also it’s recommended that the country mobilise domestic resources to ensure sustainable development
- Full Text:
- Date Issued: 2019
The obstinate notion that higher education is a meritocracy
- Sobuwa, Simpiwe, McKenna, Sioux
- Authors: Sobuwa, Simpiwe , McKenna, Sioux
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187150 , vital:44574 , xlink:href="https://doi.org/10.14426/cristal.v7i2.184"
- Description: Student success is an enormous concern in light of the high drop-out rates in South African universities. There is a wealth of local and international research which provides complex explanations for these statistics, but the common-sense understanding is that those students who have the right attributes and who work hard will do well. While the notion of higher education as a meritocracy is pervasive, it is invalid given the effects of numerous other mechanisms at play in the students' educational experiences. This article draws from the literature to discuss the problems of the meritocratic explanation in how it fails to sufficiently account for the centrality of agency and the ways in which this intersects with societal structures. We argue that more useful understandings of student success and failure require social theory that acknowledges the complexities underpinning student success or failure.
- Full Text:
- Date Issued: 2019
- Authors: Sobuwa, Simpiwe , McKenna, Sioux
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187150 , vital:44574 , xlink:href="https://doi.org/10.14426/cristal.v7i2.184"
- Description: Student success is an enormous concern in light of the high drop-out rates in South African universities. There is a wealth of local and international research which provides complex explanations for these statistics, but the common-sense understanding is that those students who have the right attributes and who work hard will do well. While the notion of higher education as a meritocracy is pervasive, it is invalid given the effects of numerous other mechanisms at play in the students' educational experiences. This article draws from the literature to discuss the problems of the meritocratic explanation in how it fails to sufficiently account for the centrality of agency and the ways in which this intersects with societal structures. We argue that more useful understandings of student success and failure require social theory that acknowledges the complexities underpinning student success or failure.
- Full Text:
- Date Issued: 2019
The origin of bedrock depression wetlands in the southern Cape of South Africa: a changing perspective
- Authors: Ellery, Steven
- Date: 2019
- Subjects: Wetlands -- South Africa -- Eastern Cape , Geomorphology -- South Africa -- Eastern Cape , Physical geography -- South Africa -- Eastern Cape , Erosion -- South Africa -- Eastern Cape , Evolutionary paleoecology -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67833 , vital:29152
- Description: The predominant theory of the origin of depression wetlands in southern Africa was developed by Goudie and Thomas (1985) and focuses primarily on mechanisms relating to deflation and erosion as the main drivers of wetland formation. This theory is based on wind driven deflation of animal watering areas where heavy grazing and trampling of vegetation promotes removal of sediment over short periods of time by wind, to create local depressions and impoundment of water. However, this theory applies in arid and semi-arid areas where grazing can reduce vegetation sufficiently to lead to deflation but does not fully explain the origins of depression wetlands that have formed in moist climates or on ancient erosion surfaces such as the African Erosion Surface (AES). This study investigates the origin of a depression wetland that has formed on sandstone bedrock through weathering and dissolution on the AES in South Africa. Wetlands like this act as groundwater recharge zones such that water flows away from the centre of the depression, taking with it any dissolved solutes derived from weathering of the bed of the depression. Fluctuations between wet and dry periods create both highly reducing conditions (during wet phases) and highly oxidising conditions (during dry phases) beneath the margins of these depression wetlands. Some of the main constituents of the sandstone in this wetland are iron(III) oxides, which are highly sensitive to redox conditions and have therefore been transported to and trapped in the margins of the depression. The redistribution of iron(III) oxides from the centre towards the margins of the depression has caused a net volume loss in the centre of the depression, causing sagging, and a net volume gain at the margins of the depression associated with swelling. This process occurs over periods upwards of a million years and explains the presence of depression wetlands in moist climates.
- Full Text:
- Date Issued: 2019
- Authors: Ellery, Steven
- Date: 2019
- Subjects: Wetlands -- South Africa -- Eastern Cape , Geomorphology -- South Africa -- Eastern Cape , Physical geography -- South Africa -- Eastern Cape , Erosion -- South Africa -- Eastern Cape , Evolutionary paleoecology -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67833 , vital:29152
- Description: The predominant theory of the origin of depression wetlands in southern Africa was developed by Goudie and Thomas (1985) and focuses primarily on mechanisms relating to deflation and erosion as the main drivers of wetland formation. This theory is based on wind driven deflation of animal watering areas where heavy grazing and trampling of vegetation promotes removal of sediment over short periods of time by wind, to create local depressions and impoundment of water. However, this theory applies in arid and semi-arid areas where grazing can reduce vegetation sufficiently to lead to deflation but does not fully explain the origins of depression wetlands that have formed in moist climates or on ancient erosion surfaces such as the African Erosion Surface (AES). This study investigates the origin of a depression wetland that has formed on sandstone bedrock through weathering and dissolution on the AES in South Africa. Wetlands like this act as groundwater recharge zones such that water flows away from the centre of the depression, taking with it any dissolved solutes derived from weathering of the bed of the depression. Fluctuations between wet and dry periods create both highly reducing conditions (during wet phases) and highly oxidising conditions (during dry phases) beneath the margins of these depression wetlands. Some of the main constituents of the sandstone in this wetland are iron(III) oxides, which are highly sensitive to redox conditions and have therefore been transported to and trapped in the margins of the depression. The redistribution of iron(III) oxides from the centre towards the margins of the depression has caused a net volume loss in the centre of the depression, causing sagging, and a net volume gain at the margins of the depression associated with swelling. This process occurs over periods upwards of a million years and explains the presence of depression wetlands in moist climates.
- Full Text:
- Date Issued: 2019
The perceived impact of father absence on adolescents’ self-esteem in a rural area in Mpumalanga
- Authors: Mhlongo, Lindokuhle Nqobile
- Date: 2019
- Subjects: Absentee fathers -- South Africa -- Mpumalanga , Self-esteem in adolescence Self-esteem in children Adolescent psychology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/42390 , vital:36652
- Description: There has been an upsurge in the number of single-parent female headed households which has led to the permanent absence of fathers in the lives of their children. Research has shown that the absence of fathers in the lives of their children can have negative implications for the child. This study aimed to investigate the self-esteem of adolescents from father absent families. The study was motivated by the researcher‟s observation of children from father absent families in the study area and also by the sparse South African literature in relation to the study‟s topic. In order to achieve the aim of the study, a qualitative, explorative-descriptive research design was used and an interpretive paradigm was adopted. A total number of 16 participants between ages 12-18 were recruited through a non-probability purposive sampling method. All the participants stayed in single-parent female headed households and the degree of father absence for these participants varied from fathers who were known by the participant but absent, to fathers who are unknown and absent. Data was collected through the use of one-on-one semi structured interviews that were conducted in the participants‟ home language. The data was analyzed through thematic analysis and Maslow‟s Theory of Motivation was used as a theoretical framework for interpreting the study‟s findings. Negative emotions towards self, feelings of inferiority and feelings of worthlessness were identified amongst the participants and these are indicative of low self-esteem. The participants believed that the absence of their fathers has contributed towards these negative feelings as they went through financial difficulties, abandonment/rejection, had threatened sense of belonging and also went through self- personalization of father absence. Additionally, several protective factors were identified and these enabled the participants to cope with the absence of their fathers. However, some of the participants indicated a positive sense of worth which they attributed mostly to the love they receive from others.
- Full Text:
- Date Issued: 2019
- Authors: Mhlongo, Lindokuhle Nqobile
- Date: 2019
- Subjects: Absentee fathers -- South Africa -- Mpumalanga , Self-esteem in adolescence Self-esteem in children Adolescent psychology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/42390 , vital:36652
- Description: There has been an upsurge in the number of single-parent female headed households which has led to the permanent absence of fathers in the lives of their children. Research has shown that the absence of fathers in the lives of their children can have negative implications for the child. This study aimed to investigate the self-esteem of adolescents from father absent families. The study was motivated by the researcher‟s observation of children from father absent families in the study area and also by the sparse South African literature in relation to the study‟s topic. In order to achieve the aim of the study, a qualitative, explorative-descriptive research design was used and an interpretive paradigm was adopted. A total number of 16 participants between ages 12-18 were recruited through a non-probability purposive sampling method. All the participants stayed in single-parent female headed households and the degree of father absence for these participants varied from fathers who were known by the participant but absent, to fathers who are unknown and absent. Data was collected through the use of one-on-one semi structured interviews that were conducted in the participants‟ home language. The data was analyzed through thematic analysis and Maslow‟s Theory of Motivation was used as a theoretical framework for interpreting the study‟s findings. Negative emotions towards self, feelings of inferiority and feelings of worthlessness were identified amongst the participants and these are indicative of low self-esteem. The participants believed that the absence of their fathers has contributed towards these negative feelings as they went through financial difficulties, abandonment/rejection, had threatened sense of belonging and also went through self- personalization of father absence. Additionally, several protective factors were identified and these enabled the participants to cope with the absence of their fathers. However, some of the participants indicated a positive sense of worth which they attributed mostly to the love they receive from others.
- Full Text:
- Date Issued: 2019
The performance and preference of a specialist herbivore, Catorhintha schaffneri (Coreidae), on its polytypic host plant, Pereskia aculeata (Cactaceae)
- Authors: Egbon, Ikponmwosa Nathaniel
- Date: 2019
- Subjects: Insects and biological pest control agents -- South Africa , Pereskia -- Biological control -- South Africa , Cactus -- Biological control -- South Africa , Coreida-- South Africa , Invasive plants -- Biological control -- South Africa , Catorhintha schaffneri
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/68250 , vital:29223
- Description: Plant species moved beyond their natural ranges may be liberated into enemy-free spaces, where they increase resource allocation to fitness, rather than defence against natural enemies, and become invasive as suggested by the Evolution of Increased Competitive Ability (EICA) Hypothesis. Several cacti are notable invaders and are targeted for biological control. The leafy cactus, Pereskia aculeata Miller, introduced into South Africa from South America, has become a target for biological control after becoming invasive. The absence of natural enemies of P. aculeata in the introduced range may be the reason for its invasiveness. This thesis seeks to investigate the role of the evolution of increased competitive ability (enemy release) as the probable driver of P. aculeata’s success, and ascertain how the plant’s intraspecific variation influences the impact, fitness of, and preference by its biological control agent, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), in South Africa. Enemy release and evolution of traits in P. aculeata were examined by quantifying plant growth parameters of fifteen genotypes of P. aculeata from both the native and invaded distribution of the plant. Ten genotypes of P. aculeata were used in testing the effect of agent herbivory (impact and damage) under similar conditions. These studies indicated that most invaded-range genotypes were more vigorous than the native genotypes. Rapid growth may account for the quick access of invasive genotypes of P. aculeata to tree canopies. Catorhintha schaffneri damage varied between genotypes but differences in the damage and impact from the agent could not be explained by whether the plant originated in the introduced or native distribution. In sum, while the growth of the invasive genotypes largely conforms to the EICA hypothesis, the impact of C. schaffneri did not support the hypothesis. The influence of host variation in P. aculeata on the fitness of C. schaffneri within the context of local adaptation to plant genotypes from different localities was tested using agent survival, stage-specific and total developmental time, and the extent of damage to ten host genotypes. Maw’s Host Suitability Index (HIS) and Dobie’s Susceptibility Index (DSI) showed the preference by and performance of C. schaffneri on the different genotypes of the plant. Catorhintha schaffneri survived to the adult stage on 70% of genotypes tested. Evidence consistent with the assumption that C. schaffneri would be fitter on the native genotypes than the invasive genotypes due to local adaptation was not found. In addition, there was no evidence in support of fitter agents on the invasive genotypes than on the native genotypes as proposed by EICA hypothesis. Catorhintha schaffneri developed equally well on the invasive genotypes of P. aculeata as on the native genotypes. To establish whether host variation would affect diet selection by C. schaffneri, both nymphs and adults were examined in paired-choice and multiple-choice trials. The nymphs and adults chose their hosts regardless of host genotype differences. The agent may be good at selecting good succulent shoots from bad shoots, but is incapable of distinguishing a good host genotype from a poorer one. This thesis shows, therefore, that P. aculeata and its array of genotypes in South Africa could be effectively controlled by C. schaffneri, as it has the potential to suitably utilise and impact the different genotypes of the weed in South Africa with neither any demonstrable preference nor local adaptation for the native genotypes. Consequently, the use of C. schaffneri, as a biological control agent in the weed biological control programme of P. aculeata remains promising, as the agent is insensitive to the intraspecific variation of the invasive host plants.
- Full Text:
- Date Issued: 2019
- Authors: Egbon, Ikponmwosa Nathaniel
- Date: 2019
- Subjects: Insects and biological pest control agents -- South Africa , Pereskia -- Biological control -- South Africa , Cactus -- Biological control -- South Africa , Coreida-- South Africa , Invasive plants -- Biological control -- South Africa , Catorhintha schaffneri
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/68250 , vital:29223
- Description: Plant species moved beyond their natural ranges may be liberated into enemy-free spaces, where they increase resource allocation to fitness, rather than defence against natural enemies, and become invasive as suggested by the Evolution of Increased Competitive Ability (EICA) Hypothesis. Several cacti are notable invaders and are targeted for biological control. The leafy cactus, Pereskia aculeata Miller, introduced into South Africa from South America, has become a target for biological control after becoming invasive. The absence of natural enemies of P. aculeata in the introduced range may be the reason for its invasiveness. This thesis seeks to investigate the role of the evolution of increased competitive ability (enemy release) as the probable driver of P. aculeata’s success, and ascertain how the plant’s intraspecific variation influences the impact, fitness of, and preference by its biological control agent, Catorhintha schaffneri Brailovsky and Garcia (Coreidae), in South Africa. Enemy release and evolution of traits in P. aculeata were examined by quantifying plant growth parameters of fifteen genotypes of P. aculeata from both the native and invaded distribution of the plant. Ten genotypes of P. aculeata were used in testing the effect of agent herbivory (impact and damage) under similar conditions. These studies indicated that most invaded-range genotypes were more vigorous than the native genotypes. Rapid growth may account for the quick access of invasive genotypes of P. aculeata to tree canopies. Catorhintha schaffneri damage varied between genotypes but differences in the damage and impact from the agent could not be explained by whether the plant originated in the introduced or native distribution. In sum, while the growth of the invasive genotypes largely conforms to the EICA hypothesis, the impact of C. schaffneri did not support the hypothesis. The influence of host variation in P. aculeata on the fitness of C. schaffneri within the context of local adaptation to plant genotypes from different localities was tested using agent survival, stage-specific and total developmental time, and the extent of damage to ten host genotypes. Maw’s Host Suitability Index (HIS) and Dobie’s Susceptibility Index (DSI) showed the preference by and performance of C. schaffneri on the different genotypes of the plant. Catorhintha schaffneri survived to the adult stage on 70% of genotypes tested. Evidence consistent with the assumption that C. schaffneri would be fitter on the native genotypes than the invasive genotypes due to local adaptation was not found. In addition, there was no evidence in support of fitter agents on the invasive genotypes than on the native genotypes as proposed by EICA hypothesis. Catorhintha schaffneri developed equally well on the invasive genotypes of P. aculeata as on the native genotypes. To establish whether host variation would affect diet selection by C. schaffneri, both nymphs and adults were examined in paired-choice and multiple-choice trials. The nymphs and adults chose their hosts regardless of host genotype differences. The agent may be good at selecting good succulent shoots from bad shoots, but is incapable of distinguishing a good host genotype from a poorer one. This thesis shows, therefore, that P. aculeata and its array of genotypes in South Africa could be effectively controlled by C. schaffneri, as it has the potential to suitably utilise and impact the different genotypes of the weed in South Africa with neither any demonstrable preference nor local adaptation for the native genotypes. Consequently, the use of C. schaffneri, as a biological control agent in the weed biological control programme of P. aculeata remains promising, as the agent is insensitive to the intraspecific variation of the invasive host plants.
- Full Text:
- Date Issued: 2019
The perspectives of victims of domestic violence and abuse: narratives from members of Masimanyane women’s support centre in East London, Eastern Cape Province, Resa.
- Authors: Sigodla, Asavela
- Date: 2019
- Subjects: Family violence Abused women
- Language: English
- Type: Thesis , Masters , MSoc (Criminology)
- Identifier: http://hdl.handle.net/10353/16419 , vital:40718
- Description: Domestic violence and abuse also known as Gender-based violence (GBV) including rape, mutilation, murder and sexual abuse, is a profound health problem for women across the globe. Although domestic violence and sexual abuse is a significant cause of female morbidity and mortality, it is almost never seen as a public health issue. Domestic violence and abuse can happen to anyone of any race, age, sexual orientation, religion or gender. This study draws attention on exploring victim’s narrative perspectives on domestic violence and abuse against women in East London at Masimanyane Women’s Support Centre (MWSC) in Eastern Cape Province of South Africa. The study employed a qualitative research approach, with In-Depth Interviews (IDI), Focus Group Discussions (FDGs), and review of related literature for data collection. The findings of this study were based only from participants who were victims of domestic violence and abuse, as some of the views were stated by visitors. This resulted in some situations where the witnesses of domestic violence and abuse, just like victims themselves did not want to report their incidents. Women may not reveal that they are suffering from domestic violence and abuse, as they fear of the image that they may be portraying about themselves and their family as a whole like social pressure and stigma of defamation. Although domestic abuse and violence increases all the time women are encouraged to open up on such cases about abuse. Real change in these cases can only be brought by changing the mind-set of society through education and better law enforcement. This study was anchored by both the Social Learning Theory and Feminist Theory. Upon recommendations, this study has seen that there should be government interventions and programs that help victims of domestic violence and abuse and also to work in a way of preventing the domestic violence and abuse.
- Full Text:
- Date Issued: 2019
- Authors: Sigodla, Asavela
- Date: 2019
- Subjects: Family violence Abused women
- Language: English
- Type: Thesis , Masters , MSoc (Criminology)
- Identifier: http://hdl.handle.net/10353/16419 , vital:40718
- Description: Domestic violence and abuse also known as Gender-based violence (GBV) including rape, mutilation, murder and sexual abuse, is a profound health problem for women across the globe. Although domestic violence and sexual abuse is a significant cause of female morbidity and mortality, it is almost never seen as a public health issue. Domestic violence and abuse can happen to anyone of any race, age, sexual orientation, religion or gender. This study draws attention on exploring victim’s narrative perspectives on domestic violence and abuse against women in East London at Masimanyane Women’s Support Centre (MWSC) in Eastern Cape Province of South Africa. The study employed a qualitative research approach, with In-Depth Interviews (IDI), Focus Group Discussions (FDGs), and review of related literature for data collection. The findings of this study were based only from participants who were victims of domestic violence and abuse, as some of the views were stated by visitors. This resulted in some situations where the witnesses of domestic violence and abuse, just like victims themselves did not want to report their incidents. Women may not reveal that they are suffering from domestic violence and abuse, as they fear of the image that they may be portraying about themselves and their family as a whole like social pressure and stigma of defamation. Although domestic abuse and violence increases all the time women are encouraged to open up on such cases about abuse. Real change in these cases can only be brought by changing the mind-set of society through education and better law enforcement. This study was anchored by both the Social Learning Theory and Feminist Theory. Upon recommendations, this study has seen that there should be government interventions and programs that help victims of domestic violence and abuse and also to work in a way of preventing the domestic violence and abuse.
- Full Text:
- Date Issued: 2019
The photo-physicochemical properties and in vitro photodynamic therapy activity of differently substituted-zinc (II)-phthalocyanines and graphene quantum dots conjugates on MCF7 breast cancer cell line
- Nene, Lindokuhle C, Managa, Muthumuni E, Oluwole, David O, Mafukidze, Donovan M, Sindelo, Azole, Nyokong, Tebello
- Authors: Nene, Lindokuhle C , Managa, Muthumuni E , Oluwole, David O , Mafukidze, Donovan M , Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187449 , vital:44653 , xlink:href="https://doi.org/10.1016/j.ica.2019.01.012"
- Description: Several differently substituted Zn(II) phthalocyanines (ZnPcs) were prepared and conjugated to GQDs. The photophysical properties were determined for both the Pcs and their respective conjugates including the fluorescence/triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pcs decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields, this is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of the reduced actual number of Pcs units provided in the conjugate for therapy. Upon introduction of cationic charges, the photodynamic therapy activity of the complexes increased.
- Full Text:
- Date Issued: 2019
- Authors: Nene, Lindokuhle C , Managa, Muthumuni E , Oluwole, David O , Mafukidze, Donovan M , Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187449 , vital:44653 , xlink:href="https://doi.org/10.1016/j.ica.2019.01.012"
- Description: Several differently substituted Zn(II) phthalocyanines (ZnPcs) were prepared and conjugated to GQDs. The photophysical properties were determined for both the Pcs and their respective conjugates including the fluorescence/triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pcs decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields, this is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of the reduced actual number of Pcs units provided in the conjugate for therapy. Upon introduction of cationic charges, the photodynamic therapy activity of the complexes increased.
- Full Text:
- Date Issued: 2019
The photophysicochemical properties and photodynamic therapy activity of phenyldiazenyl phenoxy substituted phthalocyanines when incorporated into Pluronic® F127 micelles
- Motloung, Banele M, Sekhosana, Kutloano E, Managa, Muthumuni, Prinsloo, Earl, Nyokong, Tebello
- Authors: Motloung, Banele M , Sekhosana, Kutloano E , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186769 , vital:44532 , xlink:href="https://doi.org/10.1016/j.poly.2019.114157"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of 4(4-phenyldiazenyl) phenoxy substituted indium (III) (InPc) and zinc (ZnPc) phthalocyanines when alone or incorporated into Pluronic_ F127 micelles are presented in this study. The InPc exhibited higher singlet oxygen (UD) at 0.47 compared to the ZnPc at 0.20 in dimethylsulfoxide. The UD values in the presence of Pluronic_ F127 and in water, were 0.32 for InPc and 0.09 for ZnPc. The triplet quantum yields (UT) were 0.92 for InPc and 0.32 for ZnPc in DMSO. The PDT activity followed the same trend as the singlet oxygen quantum yields. At the highest concentration, InPc in Pluronic_ F127 gave 22% cell viability compared to 34% for complex ZnPc. The partition coefficient Kp values were determined using the water and octanol system. InPc had a larger Kp suggesting that it is more likely to be taken up by the cancer cells, hence it exhibited better PDT activity.
- Full Text:
- Date Issued: 2019
- Authors: Motloung, Banele M , Sekhosana, Kutloano E , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186769 , vital:44532 , xlink:href="https://doi.org/10.1016/j.poly.2019.114157"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of 4(4-phenyldiazenyl) phenoxy substituted indium (III) (InPc) and zinc (ZnPc) phthalocyanines when alone or incorporated into Pluronic_ F127 micelles are presented in this study. The InPc exhibited higher singlet oxygen (UD) at 0.47 compared to the ZnPc at 0.20 in dimethylsulfoxide. The UD values in the presence of Pluronic_ F127 and in water, were 0.32 for InPc and 0.09 for ZnPc. The triplet quantum yields (UT) were 0.92 for InPc and 0.32 for ZnPc in DMSO. The PDT activity followed the same trend as the singlet oxygen quantum yields. At the highest concentration, InPc in Pluronic_ F127 gave 22% cell viability compared to 34% for complex ZnPc. The partition coefficient Kp values were determined using the water and octanol system. InPc had a larger Kp suggesting that it is more likely to be taken up by the cancer cells, hence it exhibited better PDT activity.
- Full Text:
- Date Issued: 2019
The Politics of Language Education in Africa:
- Kaschula, Russell H, Kretzer, Michael M
- Authors: Kaschula, Russell H , Kretzer, Michael M
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/174739 , vital:42505 , ISBN , https://doi.org/10.1093/acrefore/9780190228637.013.750
- Description: Language policies in sub-Saharan African nations emerge out of specific political, historical, socioeconomic, and linguistic conditions. Education plays a crucial role for all spheres of language policy. Policies either upgrade or downgrade indigenous languages through their application at various educational institutions. The most significant example is the selection of the language (s) used as languages of learning and teaching at higher-education institutions. The region’s colonial history also influences the language policies of the independent African states. Language policy in Senegal is an example of a francophone country focusing on a linguistic assimilation policy in which minor reforms in favor of indigenous languages have taken place.
- Full Text:
- Date Issued: 2019
- Authors: Kaschula, Russell H , Kretzer, Michael M
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/174739 , vital:42505 , ISBN , https://doi.org/10.1093/acrefore/9780190228637.013.750
- Description: Language policies in sub-Saharan African nations emerge out of specific political, historical, socioeconomic, and linguistic conditions. Education plays a crucial role for all spheres of language policy. Policies either upgrade or downgrade indigenous languages through their application at various educational institutions. The most significant example is the selection of the language (s) used as languages of learning and teaching at higher-education institutions. The region’s colonial history also influences the language policies of the independent African states. Language policy in Senegal is an example of a francophone country focusing on a linguistic assimilation policy in which minor reforms in favor of indigenous languages have taken place.
- Full Text:
- Date Issued: 2019
The posttraumatic growth of Oprah Winfrey: a psychobiography
- Authors: Oosthuysen, Yolandé
- Date: 2019
- Subjects: Winfrey, Oprah , Posttraumatic growth Psychology -- Biographical methods , Post-traumatic stress disorder -- Patients -- Rehabilitation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/43115 , vital:36737
- Description: Posttraumatic growth is a unique outcome of trauma that is relatively new to empirical investigation and not yet fully understood. Psychobiographies provide a valuable method to interpret and evaluate the applicability of psychological theories, such as posttraumatic growth. This study explored the unique manifestation of posttraumatic growth in the life of Oprah Winfrey. An exploratory-descriptive design was employed to examine the life history of Winfrey. She was selected through purposive sampling, based on her traumatic life history and extraordinary success in the television industry. Primary and secondary sources of biographical and historical data were used during the process of data collection. The data was processed according to Alexander’s data analysis method in conjunction with an analytic framework to organise the data. To maintain ethical principles, the researcher was guided by respect, empathy and accountability in dealing with any personal information regarding Winfrey. The findings demonstrated the occurrence of all five factors of the posttraumatic growth model, proposed by Calhoun and Tedeschi, in Winfrey’s life. The order of these factors, according to a number of identified instances in the data, matched the order of variance percentages per factor identified by Tedeschi and Calhoun. The analysis of PTG in the life of Winfrey, according to the PTG theoretical model, indicates the applicability and value of the model to interpret positive change as it manifests in the lives of individuals after trauma.
- Full Text:
- Date Issued: 2019
- Authors: Oosthuysen, Yolandé
- Date: 2019
- Subjects: Winfrey, Oprah , Posttraumatic growth Psychology -- Biographical methods , Post-traumatic stress disorder -- Patients -- Rehabilitation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/43115 , vital:36737
- Description: Posttraumatic growth is a unique outcome of trauma that is relatively new to empirical investigation and not yet fully understood. Psychobiographies provide a valuable method to interpret and evaluate the applicability of psychological theories, such as posttraumatic growth. This study explored the unique manifestation of posttraumatic growth in the life of Oprah Winfrey. An exploratory-descriptive design was employed to examine the life history of Winfrey. She was selected through purposive sampling, based on her traumatic life history and extraordinary success in the television industry. Primary and secondary sources of biographical and historical data were used during the process of data collection. The data was processed according to Alexander’s data analysis method in conjunction with an analytic framework to organise the data. To maintain ethical principles, the researcher was guided by respect, empathy and accountability in dealing with any personal information regarding Winfrey. The findings demonstrated the occurrence of all five factors of the posttraumatic growth model, proposed by Calhoun and Tedeschi, in Winfrey’s life. The order of these factors, according to a number of identified instances in the data, matched the order of variance percentages per factor identified by Tedeschi and Calhoun. The analysis of PTG in the life of Winfrey, according to the PTG theoretical model, indicates the applicability and value of the model to interpret positive change as it manifests in the lives of individuals after trauma.
- Full Text:
- Date Issued: 2019
The potential for concept cartoons to assist natural sciences teachers with developing scientific jargon for primary school learners
- Authors: Abrahams, Warda
- Date: 2019
- Subjects: Science--Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10948/40219 , vital:35984
- Description: The study was undertaken to investigate whether a teaching tool Concept Cartoons may assist Intermediate Phase (IP) Natural Sciences teachers with the development and understanding of scientific jargon, when implemented in Natural Sciences investigations. As a novice Natural Sciences teacher it was important to find a teaching tool which would assist second language learners with scientific concepts, particularly focusing on science investigations. The focal aim was to search for a fun, captivating, educational resource that would cater for these learners’ barriers to science learning. This research falls within a constructivist worldview, and the research method employed was a case study. Data were collected through qualitative approach, via semi-structured interviews. A total of nine participating Intermediate Phase Natural Sciences teachers from the Port Elizabeth Northern Areas schools contributed towards the findings of this study. This study was an investigation undertaken to see whether a different teaching approach may encourage change. The findings of this study suggested that Concept Cartoons used in Natural Sciences investigations created an educational effect towards the learners understanding of science concepts. Intermediate Phase learners were introduced to Concept Cartoons to assist with their understanding of science terminology during practical investigations. The results of this investigation suggested that Concept Cartoons assisted English second-language learners with scientific jargon and served as an educative curriculum material for Intermediate Phase teachers. Furthermore Grade 4 findings suggested English home-language speakers struggled with scientific language, compared to their second-language peers who achieved greater results due to the amount of effort and determination they dedicated to translating these concepts. Further studies suggested this maybe because science terminology does not form part of their everyday vocabulary, therefore experiencing difficulty with scien1. Concept Cartoons: teachers and scientific investigations 2. Concept Cartoons: design, characters and speech bubbles 3. Concept Cartoons: enabling scientific talk 4. Concept Cartoons: scientific jargon 5. Concept Cartoons: scientific jargon and ESL learners 6. Concept Cartoons: teacher learning. This study, which aimed at introducing Concept Cartoons as an educative curriculum tool in Natural Sciences investigations, is expected to fill an important gap in literature surrounding teaching science jargon to English second-language learners.
- Full Text:
- Date Issued: 2019
- Authors: Abrahams, Warda
- Date: 2019
- Subjects: Science--Study and teaching
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10948/40219 , vital:35984
- Description: The study was undertaken to investigate whether a teaching tool Concept Cartoons may assist Intermediate Phase (IP) Natural Sciences teachers with the development and understanding of scientific jargon, when implemented in Natural Sciences investigations. As a novice Natural Sciences teacher it was important to find a teaching tool which would assist second language learners with scientific concepts, particularly focusing on science investigations. The focal aim was to search for a fun, captivating, educational resource that would cater for these learners’ barriers to science learning. This research falls within a constructivist worldview, and the research method employed was a case study. Data were collected through qualitative approach, via semi-structured interviews. A total of nine participating Intermediate Phase Natural Sciences teachers from the Port Elizabeth Northern Areas schools contributed towards the findings of this study. This study was an investigation undertaken to see whether a different teaching approach may encourage change. The findings of this study suggested that Concept Cartoons used in Natural Sciences investigations created an educational effect towards the learners understanding of science concepts. Intermediate Phase learners were introduced to Concept Cartoons to assist with their understanding of science terminology during practical investigations. The results of this investigation suggested that Concept Cartoons assisted English second-language learners with scientific jargon and served as an educative curriculum material for Intermediate Phase teachers. Furthermore Grade 4 findings suggested English home-language speakers struggled with scientific language, compared to their second-language peers who achieved greater results due to the amount of effort and determination they dedicated to translating these concepts. Further studies suggested this maybe because science terminology does not form part of their everyday vocabulary, therefore experiencing difficulty with scien1. Concept Cartoons: teachers and scientific investigations 2. Concept Cartoons: design, characters and speech bubbles 3. Concept Cartoons: enabling scientific talk 4. Concept Cartoons: scientific jargon 5. Concept Cartoons: scientific jargon and ESL learners 6. Concept Cartoons: teacher learning. This study, which aimed at introducing Concept Cartoons as an educative curriculum tool in Natural Sciences investigations, is expected to fill an important gap in literature surrounding teaching science jargon to English second-language learners.
- Full Text:
- Date Issued: 2019
The prediction of, and changes in,medullated fibre levels when processing mohair into top
- Authors: Van Zyl, Andreas Marius
- Date: 2019
- Subjects: Mohair Industry -- South Africa , Textile Fibers Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45767 , vital:38962
- Description: The prediction of, and changes in, medullated fibre levels during early stage processing of mohair, from greasy to top, have been studied. Commercial lots, representative of the South African and Basuto mohair clips, covering a wide range of properties, with respect to objectionable medullated (kemp type) fibres, length and fibre diameter, were sampled for testing at three different processing stages, viz. greasy, preparatory gilled sliver, and top. All samples were tested with an Optical Fibre Diameter Analyser (OFDA100) for medullated- and fibre diameter related properties. Various statistical analyses were conducted to determine the most significant correlations and best prediction of changes in medullated fibre levels, during processing. As expected, the medullated fibre levels of the Basuto lots were much higher than those of the Cape lots. Moreover, the inclusion or exclusion of flat fibres, in combination with other medullated fibres, resulted in significant differences in the outcome of some of the statistical analysis. It was found that flat fibre levels were highly correlated with the standard deviation of fibre diameter at all processing stages, and also, the greasy standard deviation of fibre diameter was the best predictor of flat fibre levels in the top. Further, the percentage reduction in flat fibres, from greasy to preparatory gilled sliver, was more than double that of the reduction in flat fibres from preparatory gilled sliver to top. Similarly, the percentage reduction in objectionable medullated (including flat) fibres, from greasy to preparatory gilled sliver, was about 1.7 times more than that of the reduction from preparatory gilled sliver to top.
- Full Text:
- Date Issued: 2019
- Authors: Van Zyl, Andreas Marius
- Date: 2019
- Subjects: Mohair Industry -- South Africa , Textile Fibers Testing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/45767 , vital:38962
- Description: The prediction of, and changes in, medullated fibre levels during early stage processing of mohair, from greasy to top, have been studied. Commercial lots, representative of the South African and Basuto mohair clips, covering a wide range of properties, with respect to objectionable medullated (kemp type) fibres, length and fibre diameter, were sampled for testing at three different processing stages, viz. greasy, preparatory gilled sliver, and top. All samples were tested with an Optical Fibre Diameter Analyser (OFDA100) for medullated- and fibre diameter related properties. Various statistical analyses were conducted to determine the most significant correlations and best prediction of changes in medullated fibre levels, during processing. As expected, the medullated fibre levels of the Basuto lots were much higher than those of the Cape lots. Moreover, the inclusion or exclusion of flat fibres, in combination with other medullated fibres, resulted in significant differences in the outcome of some of the statistical analysis. It was found that flat fibre levels were highly correlated with the standard deviation of fibre diameter at all processing stages, and also, the greasy standard deviation of fibre diameter was the best predictor of flat fibre levels in the top. Further, the percentage reduction in flat fibres, from greasy to preparatory gilled sliver, was more than double that of the reduction in flat fibres from preparatory gilled sliver to top. Similarly, the percentage reduction in objectionable medullated (including flat) fibres, from greasy to preparatory gilled sliver, was about 1.7 times more than that of the reduction from preparatory gilled sliver to top.
- Full Text:
- Date Issued: 2019
The predictors of student performance in a blended learning environment at Higher Education Institutions (HEIs) in Tanzania: a case study conducted at the University of Dar-es-Salaam
- Authors: Kabudi, Tumaini John
- Date: 2019
- Subjects: Prediction of scholastic success -- Tanzania -- Case studies , Motivation in education -- Tanzania -- Case studies , Academic achievement -- Tanzania -- Case studies , Blended learning -- Tanzania -- Case studies , Chuo Kikuu cha Dar es Salaam -- Students
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68358 , vital:29242
- Description: Blended Learning is an important technological platform which has the potential to enhance the efficiency and efficacy of educational provision, especially in Tanzania universities. Despite a high level of investment into Blended learning, students face various challenges that have impeded them performing well in Blended learning courses. The purpose of this research is to examine and explore how student’s performance in a Blended learning environment is influenced by motivation and learning strategies; using the University of Dar es Salaam as a case study. This is a pragmatic research that utilises a mixed research design. The research design includes both qualitative design (in-depth single case study) and quantitative design (survey). The target population for this study is students participating in Blended learning modules. Primary data will be collected by means of Motivational Strategies for Learning Questionnaire and observation. It was found that motivation and learning strategies are significant predictors of student performance in a Blended learning environment. In terms of the motivation categories, Intrinsic Goal Orientation and Self-efficacy have statistically significant effect on student performance. With learning strategies sub factors, it was found out that Rehearsal, Effort Regulation and Peer Learning have significance effect on student performance. Moreover, age and gender significantly influence performance. The findings obtained are significant in building a better understanding of the influence that the mentioned predictors have on predicting the performance of students in Blended learning courses in Tanzania.
- Full Text:
- Date Issued: 2019
- Authors: Kabudi, Tumaini John
- Date: 2019
- Subjects: Prediction of scholastic success -- Tanzania -- Case studies , Motivation in education -- Tanzania -- Case studies , Academic achievement -- Tanzania -- Case studies , Blended learning -- Tanzania -- Case studies , Chuo Kikuu cha Dar es Salaam -- Students
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68358 , vital:29242
- Description: Blended Learning is an important technological platform which has the potential to enhance the efficiency and efficacy of educational provision, especially in Tanzania universities. Despite a high level of investment into Blended learning, students face various challenges that have impeded them performing well in Blended learning courses. The purpose of this research is to examine and explore how student’s performance in a Blended learning environment is influenced by motivation and learning strategies; using the University of Dar es Salaam as a case study. This is a pragmatic research that utilises a mixed research design. The research design includes both qualitative design (in-depth single case study) and quantitative design (survey). The target population for this study is students participating in Blended learning modules. Primary data will be collected by means of Motivational Strategies for Learning Questionnaire and observation. It was found that motivation and learning strategies are significant predictors of student performance in a Blended learning environment. In terms of the motivation categories, Intrinsic Goal Orientation and Self-efficacy have statistically significant effect on student performance. With learning strategies sub factors, it was found out that Rehearsal, Effort Regulation and Peer Learning have significance effect on student performance. Moreover, age and gender significantly influence performance. The findings obtained are significant in building a better understanding of the influence that the mentioned predictors have on predicting the performance of students in Blended learning courses in Tanzania.
- Full Text:
- Date Issued: 2019
The preparation of BODIPY and porphyrin dyes and their cyclodextrin inclusion complexes and Pluronic® F-127 encapsulation micelles for use in PDT and PACT
- Authors: Molupe, Nthabeleng
- Date: 2019
- Subjects: Dyes and dyeing -- Chemistry , Drug delivery systems , Fluorescence spectroscopy , Cancer -- Photochemotherapy , Photosensitizing compounds -- Therapeutic use , Cyclodextrins -- Biotechnology , Nanoparticles
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/117574 , vital:34528
- Description: Several novel BODIPY dyes ((4,4′-difluoro-1,7-tetramethyl-3,5-(3-dithiophene)-2,6-diiodo-8-(4-dimethylamino)-4-bora-3a,4a-diaza-s-indacene (1c), 4,4′-difluoro-1,7-tetramethyl-3,5-(3 dithiophene)-2,6-diiodo-8-(4-methylthio)-4-bora-3a,4a-diaza-s-indacene (3c) and 4,4′-difluoro-1,7-tetramethyl-3,5-(4-dibenzyloxybenzene)-2,6-diiodo-8-(4-methylbenzoate)-4 bora-3a,4a-diaza-s-indacene (4c)) and porphyrins (tetraacenaphthylporphyrin (7a) and Sn(IV) tetraacenaphthylporphyrin (7b)) were synthesized and characterized. Previously reported BODIPY dyes (4,4′-difluoro-1,7-tetramethyl-3,5-(2-dihydroxy)-2,6-diiodo-8-(4-bromo)-4-bora-3a,4a-diaza-s-indacene (5) and 4,4′-difluoro-1,7-tetramethyl-3,5-(2-dithiophene)-2,6-diiodo-8-(phenyl)-4-bora-3a,4a-diaza-s-indacene (6)) were also used. Pluronic® F-127 and cyclodextrins were used as solubilizing drug delivery agents for the synthesized BODIPY dyes. The encapsulation of BODIPY dyes with Pluronic® F-127 micelles improved the water solubility of the BODIPY 5. Further modification of Pluronic® F-127 by coating with folate-functionalized chitosan for targeted delivery of BODIPY 1c and 6 was explored. The BODIPY dyes and their encapsulation complexes exhibited significant inhibition of human MCF-7 breast cancer cell growth. When cyclodextrins were used as nanocarriers, the inclusion complexes of BODIPY 4c with mβCD were found to enhance the water-solubility of the dye. Greater photoinactivation of Staphylococcus aureus was observed for the inclusion complexes when compared to the effect of solutions of non-complexed BODIPY 4c. The cyclodextrin inclusion complexes of porphyrin 7b with mβCD were also found to enhance the water-solubility of 7b. When the photodynamic effect was evaluated, solutions of the porphyrin alone and their inclusion complexes were found to have significant photodynamic effects against human MCF-7 breast cancer cells.
- Full Text:
- Date Issued: 2019
- Authors: Molupe, Nthabeleng
- Date: 2019
- Subjects: Dyes and dyeing -- Chemistry , Drug delivery systems , Fluorescence spectroscopy , Cancer -- Photochemotherapy , Photosensitizing compounds -- Therapeutic use , Cyclodextrins -- Biotechnology , Nanoparticles
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/117574 , vital:34528
- Description: Several novel BODIPY dyes ((4,4′-difluoro-1,7-tetramethyl-3,5-(3-dithiophene)-2,6-diiodo-8-(4-dimethylamino)-4-bora-3a,4a-diaza-s-indacene (1c), 4,4′-difluoro-1,7-tetramethyl-3,5-(3 dithiophene)-2,6-diiodo-8-(4-methylthio)-4-bora-3a,4a-diaza-s-indacene (3c) and 4,4′-difluoro-1,7-tetramethyl-3,5-(4-dibenzyloxybenzene)-2,6-diiodo-8-(4-methylbenzoate)-4 bora-3a,4a-diaza-s-indacene (4c)) and porphyrins (tetraacenaphthylporphyrin (7a) and Sn(IV) tetraacenaphthylporphyrin (7b)) were synthesized and characterized. Previously reported BODIPY dyes (4,4′-difluoro-1,7-tetramethyl-3,5-(2-dihydroxy)-2,6-diiodo-8-(4-bromo)-4-bora-3a,4a-diaza-s-indacene (5) and 4,4′-difluoro-1,7-tetramethyl-3,5-(2-dithiophene)-2,6-diiodo-8-(phenyl)-4-bora-3a,4a-diaza-s-indacene (6)) were also used. Pluronic® F-127 and cyclodextrins were used as solubilizing drug delivery agents for the synthesized BODIPY dyes. The encapsulation of BODIPY dyes with Pluronic® F-127 micelles improved the water solubility of the BODIPY 5. Further modification of Pluronic® F-127 by coating with folate-functionalized chitosan for targeted delivery of BODIPY 1c and 6 was explored. The BODIPY dyes and their encapsulation complexes exhibited significant inhibition of human MCF-7 breast cancer cell growth. When cyclodextrins were used as nanocarriers, the inclusion complexes of BODIPY 4c with mβCD were found to enhance the water-solubility of the dye. Greater photoinactivation of Staphylococcus aureus was observed for the inclusion complexes when compared to the effect of solutions of non-complexed BODIPY 4c. The cyclodextrin inclusion complexes of porphyrin 7b with mβCD were also found to enhance the water-solubility of 7b. When the photodynamic effect was evaluated, solutions of the porphyrin alone and their inclusion complexes were found to have significant photodynamic effects against human MCF-7 breast cancer cells.
- Full Text:
- Date Issued: 2019