List of Titles

The characteristics and trends of rainfall on sub-Antarctic Marion Island and associated air circulation patterns

Authors: Mapuka, Fortunate Nomsa
Date: 2020
Language: English
Type: Thesis , Masters , MSc(Geography)
Identifier: http://hdl.handle.net/10353/18698 , vital:42725
Description: Marion Island (46°54ʹS, 37°45ʹE) located in the Southern Ocean possesses one of the most oceanic climates on earth and sensitive to climate change. Climatologically, the sub-Antarctic is inadequately represented in the climate literature and this research therefore attempts to establish the recent changes that have occurred on Marion Island with regards to annual rainfall totals, monthly rainfall, rain days and non-rain days during the period from 1980 to 2018. This study found that annual rainfall has decreased by 24% from 2196.7 mm to 1678.57 mm from 1980 to 2018 and that the last decade (2010-2018) is the driest on record. The decrease in annual rainfall on Marion Island can be directly linked to the decreases recorded in monthly and daily rainfall. Rainfall in autumn has reduced by 35% over the last 40 years and the decrease in autumn rainfall is in part directly related to an increase in anticyclonic air circulation during which Marion Island is not influenced by any mid-latitudinal depressions. The frequency of rain days measured on Marion Island significantly decreased. Daily rainfall measuring less than 5 mm of rain a day contribute 50% of the total number of rain days. However, these high frequency low depth rainfall days contribute very little rainfall to annual totals. On Marion Island rain days that measure 10 mm and above contribute 65% of the total annual rainfall and it is also these type of high magnitude rain days that have significantly decreased since 1980. Multi-day consecutive rain events contribute the greatest proportion of rainfall to the annual rainfall totals (~40%). Linear statistics shows that the contribution to rainfall amount from these multi-day rainfall has halved since 1980. The frequency of non-rain days and consecutive non-rain days have significantly increased. The increased frequency of anticyclonic air circulation over Marion Island and the decrease of the traveling low-pressure systems affecting Marion Island are the probable cause of the increase in non-rain days. It is suggested that this increase in consecutive non-rain days has the most significant impact on the island’s biodiversity and landscape
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Date Issued: 2020

The effect of feeding varying inclusion levels of velvet bean (Mucuna pruriens) seed meal on growth performance and physicochemical attributes of broiler chicken

Authors: Mthana, Makiwa Simeon
Date: 2020
Subjects: Legumes Broilers (Chickens) Chickens -- Feeding and feeds
Language: English
Type: Thesis , Masters/Doctoral , MSc (Animal Science )
Identifier: http://hdl.handle.net/10353/12032 , vital:39129
Description: This study was conducted to determine the effect of feeding varying inclusion levels of velvet bean (Mucuna pruriens) seed meal (VBSM) on growth performance and physicochemical attributes of broiler chicken. Mucuna pruriens seed is an indigenous legume seed commonly found in tropical and sub-tropical areas; however, it can also be planted and cultivated. It is a viable source of dietary protein with an average concentration of 33.4%. Soybean is expensive. In addition, the South African production levels do not meet the current demand; hence the majority of soybean oilcake is imported. Recently, consumers have been conscious of the quality of chicken meat from both local and international producers. Therefore, there is a need to explore velvet bean that can grow in poorly fertilised and low rainfall areas. The study was conducted at Fort Cox Agriculture and Forestry Training Institute. One hundred and twelve (112) Cobb broilers were used, with an average weight of 45.2g. Four diets were formulated to be iso-caloric and iso-nitrogenous comprising velvet beans at 0, 10, 15 and 20 % (T1, T2, T3 and T4). The broilers were reared for 42 days with 35 days on experimental diets. Feed intake, body weight gain, feed conversion ratio, mortality, final body weight, carcass weight, and dressing percentage were determined. At day 42, twenty birds per treatment were randomly selected and fasted for five hours with water offered ad libitum. After slaughter the meat pH24, colour (L*, a*, b*), Warner-Bratzler shear force (WBSF), thawing loss (TL), and cooking loss (CL) measurements were performed on 80 breast and 80 thigh muscles. The data for growth performance and physicochemical parameters was analysed using General Linear Model (GLM) procedure of SAS (SAS, 2006), mean separation was done using LSD test option of SAS. Daily feed intake, body weight gain, final weight and carcass weight of broilers from T1 were significantly higher (P < 0.05) from other iii treatments. Daily feed intake (DFI), and body weight gain (BWG) in T1 were also higher (P < 0.05) in both phase 1 and phase 2 compared to other treatments. Feed conversion ratio (FCR) was not influenced by diets (P > 0.05). High (P < 0.05) mortality was observed on broilers fed diet with 0% VBSM compared to those fed diets comprising of VBSM. The diets did not have an effect (P > 0.05) on thigh meat pH24, lightness, redness, and WBSF. Cooking loss (25.69%) was higher (P < 0.05) in thigh meat of broilers fed the control diet. Breasts shear force (14.20) was higher in T4. Cooking loss of breast meat from broilers on T1 and T2 was higher (P < 0.05) than those from other treatments. Breast meat colour (P > 0.05) was not influenced by diets. It can be concluded that the VBSM has an effect on feed intake, growth performance and mortality of broilers, except on FCR and dressing percentage. It was also concluded that the VBSM can be included in broiler diets up to the level of 15% without negatively affecting the quality of meat.
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Date Issued: 2020

The effect of muscle type and freezing on the evolution of physico-chemical properties during processing of South African biltong and its final textural properties

Authors: Ngwendu, Nwabisa
Date: 2020
Subjects: Biltong Meat -- Quality -- South Africa
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/12128 , vital:39154
Description: The study investigated the effect of muscle type and freezing on evaluation of mass transfer during processing physico-chemical of South African biltong and its textural properties. In the first experimental phase of this study, mass transfers, physico-chemical and textural properties (hardness, cohesiveness, springiness, and chewiness) of commercially produced biltong from biceps femoris (BF) and semitendinosus (ST) (n=9) were measured. Biltong was dried at 30oC and 40% relative humidity until it had lost 50% of its initial weight. The initial moisture content, water activity (Aw) of BF muscles (74.3% and 0.992) were significantly lower compared those of ST muscles (75.4% and 0.994%). The fat content of BF (2.3%) muscles was higher (P<0.05) than in ST muscles (1.7%). The salt, weight and water gain for the BF muscle were 2.3%, -2.6% and -7.0% respectively and were significantly higher than those of ST muscles which were 2.1, -0.4 and -4.0, respectively. After drying, the moisture content, Aw, and pH were lower in BF (42.2, 0.886 and 5.29) than those of ST muscles (45.1, 0.911 and 5.42). The salt content was higher (P<0.05) in BF muscle than in ST. Among textural properties, hardness was significantly higher in biltong from the BF (233.0N), while the springiness was significantly lower compared to the ST muscle (178.2N). Therefore, it was concluded that the use of different muscles results in variation of biltong physicochemical characteristics. The second experiment investigated the effect of freezing and muscle type on mass transfers, lipid oxidation, physico-chemical and textural properties of biltong. In this experiment, the iii ST muscles were replaced with semimembranosus (SM) muscles. A total of 12 beef muscles were used, with six BF and six SM muscles frozen in a blast freezer at -40 oC till they reached -20oC; then they were transferred to -20oC for 14 days. The thawing loss for the BF and ST muscles was 1.3 and 2.4% respectively, but there were no significant (P>0.05) differences. The protein and salt content were significantly higher in frozen-thawed (24.3 and 0.13%) muscles than in fresh muscle (20.2 and 0.08%); whereas the fat content and pH were lower (P<0.05) in frozen-thawed (5.36) compared to fresh muscles (5.51). Between muscles, the moisture, salt content, and pH were higher in BF muscles than in SM muscles (73.2, 0.12% and 5.49). Aw was affected by the interaction between freezing and muscle type, with frozenthawed SM having lower Aw (0.990). During salting, salt, weight and water gain did not show any differences (P<0.05). There were no major significant differences after salting. There were lower TBARS and pH in frozen-thawed (1.5mgMDA/kg and 5.15) muscles than in fresh muscles (3.3mgMDA/kg and 5.19) as well as in SM muscles (1.8mgMDA/kg and 5.16) than in BF muscles (3.0mgMDA/kg and 5.19). The moisture was significantly lower in frozen-thawed SM (68.1%) than in fresh SM, BF and frozen-thawed BF (69.3,70.5 and 71.7%) after salting. On the final product, the interaction between muscle type and freezing affected the moisture content, TBARS, chewiness and the springiness of biltong, with the biltong from fresh SM (39.8%) having significantly lower moisture content compared frozenthawed BF and ST muscles as well fresh BF muscles (42.8% in average). The TBARS were higher in biltong from fresh BF muscles (5.1mgMDA/kg) compared to other muscles. Furthermore, the chewiness and springiness were higher (P<0.05) in biltong produced from SM frozen-thawed muscles (327.7N and 1.5). The WBSF was higher in biltong from the BF muscles (108.8N) than in the biltong from SM (80.1) but it was not affected by the freezing effect (P>0.05). Freezing did not show any major differences in biltong. iv The third experiment was conducted to determine the effect of freezing African buffalo carcasses on weight loss during salting, physico-chemical and textural properties of biltong. Five muscles (ST, SM, BF, LTL, and RF) were randomly selected from 30 carcasses (15 frozen-thawed and 15 fresh), cut along the grain, traditionally salted and dried at 26oC till they lost 45-50% of their initial weight. The salting weight loss was higher in frozen-thawed muscles (-1.45%) than in fresh muscles (-0.89%). The freezing treatment affected the physico-chemical properties of the biltong. The biltong produced from frozen-thawed muscles showed significantly higher protein and ash (47.6 and 7.6%) compared to fresh (43.9 and 7.1); whereas the moisture, fat, pH and Aw were lower (43.7, 2.1, 0.870 and 5.30, respectively) compared to those of biltong from fresh muscles (45.5%, 2.9%, 0.890 and 5.38). The moisture, pH and fat content were further affected by muscle type. The interactive effect was observed in salt content, with RF frozen-thawed showing higher salt content (8.2%) compared to all other muscles. The hardness and WBSF were significantly higher (P<0.05) in biltong frozen-thawed (204.1N and 135.0N) than in fresh muscles (146.2N and 113.1N). Moreover, the chewiness and springiness were affected (P<0.05) by muscle type, with RF muscle having higher springiness 0.89 and chewiness 171.1N than all the other muscles. Therefore, it can be concluded that freezing buffalo carcasses significantly influenced the quality characteristics of biltong. The fourth experiment studied the effect of drying methods on physico-chemical properties of traditional biltong produced from African buffalo muscles. The BF and SM muscles were randomly selected from 15 fresh carcasses, cut into strips, salted and divided into two batches per muscle. The first batch of each muscle type was dried in the ambient-air drier at 22oC average and the second batch in the cabinet drier at 26 oC till 45-50% weight loss. No differences (P>0.05) were observed in salting weight loss between the drying method and muscle type. The protein content was significantly higher in SM (46%) muscles compared to v BF (43%) but there was no effect (P>0.05) caused by the drying method. The interactions between the muscle type and drying method affected the fat content, with biltong from airdried BF muscles having significant lower (2.1%) fat content. There were no significant differences in other physico-chemical properties of biltong, with moisture content, salt, ash content, Aw and pH being 45.0%, 5.13%, 44.8%, 7.3%, 2.7%, 0.885 and 5.61 on average, respectively. Overall, the findings of the study show that freezing does have a significant effect on the final quality of biltong. However, it can be concluded that a significant effect on the physico-chemical properties of biltong depends on the changes of mass transfers during salting and drying.
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Date Issued: 2020

The use of information and communication technologies in agricultural development in rural areas: case of smallholder farmers in Umzimvubu Local Municipality

Authors: Makaula, Zimasa
Date: 2020
Subjects: Agricultural extension work , Information technology , Farms, Small -- South Africa -- Eastern Cape
Language: English
Type: Thesis , Masters , M Agric (Agric Extension)
Identifier: http://hdl.handle.net/10353/11994 , vital:39125
Description: Proper and timeous communication amongst different social development participants is one of the main driving factors for successful human progress. Different platforms have been used by different industries across the globe to ensure that useful information is shared with relevant structures at appropriate times. The global increase on use and availability of Information Communication Technologies (ICT’s) has prompted a thorough analysis and study of their relevance on different industries. Much of the increase has been observed mainly on highly urbanized areas, where the majority of the population is literate and who are above the poverty line. Some researchers have argued that the language used in some of the ICT’s is limited to the elite few, while others highlight cost implications in the use of these ICTs. The agricultural industry is not immune to the debates that relate to the development of ICTs, it is in most cases at the center, due to its diverse nature (in terms of participation) and close linkage to human development. There seems to be a correlation between ICT usage and the economies of scale in agricultural development, where smallholder farmers tend to use less of highly modernized ICTs, while commercial large scale farmers use more of the modernized ICTs. This disparity amongst farmers is exacerbated in many areas by the differing support systems employed by the public extension services. This study was initiated in order to study the usage and relevance of the ICTs by the smallholder farmers of the Umzimvubu Local Municipality of the Eastern Cape Province in South Africa. The research address the following research questions: 1. Which ICTs are owned by smallholder farmers of Umzimvubu local municipality? 2. Do smallholder farmers use ICTs to communicate agricultural information? 3. What are the types of ICT devices and services used by smallholder farmers for vi agricultural development? 4. What are the challenges faced by smallholder farmers when using ICTs to communicate agricultural information? A survey questionnaire was then developed to collect the relevant data from randomly selected six villages of Umzimvubu Local Municipality. The questionnaires structure employed both closed and open-ended questions that were administered using a face to face interview, conducted on the sample population in each village. The results indicated that the most common ICTs that were owned by smallholder farmers in the study area were: mobile phones (33%), televisions (TV) (28%), and radio (20%). The results also showed that communication amongst farmers (35%) and extension officers (35%) was the most notable use of mobile phone from the study area. The results also revealed that most smallholder farmers faced the following challenges when using ICTs to retrieve agricultural information; poor signal (40%), inconsistent broadcasting times for TV and radio agricultural programmes (35%), language barrier (15%) and lack of electricity (10%). The study, therefore, concludes that a majority of smallholder farmers from the study area own ICT devices necessary for rural agricultural development (mobile phones, TV and radio) that can be targeted by extension officers, policy makers, rural development implementing agencies and agro-industries to promote rural development. However, several challenges (language barrier, poor network signal and no electricity) limit the potential of these ICT devices and services from fully benefiting smallholder farmers.
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Date Issued: 2020

Towards a reconstruction of Marion Island’s glacial history

Authors: Rudolph, Elizabeth
Date: 2020
Subjects: Glacial landforms Geomorphological mapping
Language: English
Type: Thesis , Doctoral , PhD (Geography)
Identifier: http://hdl.handle.net/10353/18531 , vital:42581
Description: Southern Hemisphere glacial chronologies can provide valuable insights into interactions between glaciation and past climate changes. The sub-Antarctic Islands provide a valuable terrestrial record of glacial chronologies for the Southern Hemisphere, since they are unique, not only in size and topography, but also in oceanic situation when compared to other continental landmasses (e.g. Antarctica or Patagonia). On sub-Antarctic Marion Island, southern Indian Ocean, the exact timing and extent of the local Last Glacial Maximum is not yet known as glacial reconstructions have mostly been based on palynological proxies and relative-age dating techniques. This study presents 29 cosmogenic 36Cl exposure ages of deglaciated bedrock surfaces and moraine deposits from Marion Island. In addition, a comprehensive glacial-geomorphological map, which in conjunction with exposure ages provide improved temporal and spatial constraints for the island’s glacial history. Results show that the ice reached a local Last Glacial Maximum before 56 ka ago and retreated, with minor stillstands, until ~17 ka. This early deglaciation left island surfaces below 850 m a.s.l. ice-free after ~19 ka, and any subsequent advances during the Late Glacial or Holocene cooling periods would have been restricted to the interior. This glacial chronology is similar to that of some other sub-Antarctic Islands (e.g. the Kerguelen archipelago, Auckland and Campbell islands, and possibly South Georgia) and a number of other Southern Hemisphere glaciers (e.g. in Patagonia and New Zealand) and adds to evidence that suggest the Southern Hemisphere was in a glacial maximum earlier than the global LGM. A combination of climatic drivers such as declining temperatures, a northward migration of oceanic fronts and the Southern Hemisphere Westerly Winds (causing precipitation changes), as well as the physiography of Marion Island, created optimal conditions for glacier growth during Marine Isotope Stage 4 (MIS 4; ~65 ka ago) instead of the global LGM in MIS 2 (~18 ka). These findings redefine the glacial history of Marion Island, and have implications for future investigations on post-glacial landscape development and ecological succession.
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Date Issued: 2020

Understanding the links between smallholder farmers and retailers of meat and vegetables in Mthatha, Mqanduli, Port St Johns and Tsolo, Eastern Cape, South Africa

Authors: Qaula, Nyaniso
Date: 2020
Subjects: Farms, Small
Language: English
Type: Thesis , Masters , M Agric
Identifier: http://hdl.handle.net/10353/18823 , vital:42811
Description: It is commonly accepted that one of the challenges faced by smallholder farmers is lack of ‘access to markets’. This is especially so against the backdrop of the supermarket revolution, which is widely understood to give advantage to large-scale farmers at the expense of smallholder farmers. Given that supermarkets are now well established even within South Africa’s former homelands, it would seem that even smallholders based in these areas are at a disadvantage. The purpose of this study is to delve deeply into the market access of smallholder farmers, and to do so specifically across a large area of the former Transkei where supermarkets are well established and where there are also a range of other types of retailers. The study seeks to understand the links between smallholder farmers and diverse kinds of food retailers of meat and vegetables in and around the towns of Mthatha, Mqanduli, Port St Johns and Tsolo in the Eastern Cape Province, South Africa. For each of these sites, the study estimates the share of purchased fresh vegetables and meat that ultimately originates from smallholder farmers within the former Transkei, as opposed to large-scale farmers further afield. The findings suggest that smallholder farmers account for about 24% to 40% of fresh vegetables, and 3% to 13% of meat. The difference between vegetables and meat seems to relate to the fact that smallholder farmers account for a reasonably large share of the fresh vegetables sold by at least some supermarkets, whereas smallholder livestock farmers are largely unable to sell to abattoirs, whether because of the standards imposed by these abattoirs (including the one in Mthatha), or because of the cost of transport. The differences between sites appear to be a function of several factors, including differential market size and resource endowments. The study further sought to identify the advantages and disadvantages that the different types of retailers experience in procuring from smallholder farmers, and also identify the advantages and disadvantages that smallholder farmers experience in supplying different types of retailers. The advantage of working with smallholder farmers is that smallholder farmers can even deliver on Sundays, unlike other suppliers that refuse to work during weekends. The disadvantage is that smallholder farmers are not producing consistently therefore it is hard to rely on smallholder farmers for supply of produce. The advantage that smallholder farmers experience in supplying different types of retailers is that they get their cash right away after delivering the produce. The challenge that smallholder farmers experience when supplying food retailers is that some of the supermarkets will see the sample and order large quantity, however on the day of delivery they will complain and say it is not the good quality so the farmers must reduce the selling price. The study suggests the strategy that could be used by farmers to access the market, which is to enhance knowledge of market skills and negotiation skills.
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Date Issued: 2020

Chemical evaluation, in vitro ruminal dry matter (DM) degradability and ruminal biological activity of common browse tree fruits of Alice

Authors: Sondzaba, Bavuyise
Date: 2020-01
Subjects: Ruminants
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10353/20882 , vital:46695
Description: The objective of this study was to investigate the effect of species variations on chemical composition and in vitro ruminal degradability of Vachellia karroo, Grewia Occidentalis, Diospyros Lycioides and Ziziphus Mucronata fruits harvested from communally grazed lands in Alice, Eastern Cape Province, South Africa. The browse fruits were collected between February and May and analysed for crude protein (CP), dry matter (DM), ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), organic matter (OM) and acid detergent lignin (ADL), condensed tannins (CT), macro minerals (Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium (Na) and Phosphorus(P)) and micro minerals (Ion (Fe), Zinc (Zn), Manganese (Mn) and Copper (Cu)). There was significant variation (P<0.05) in chemical composition between browse fruits. The CP content differed significantly amongst the browse fruits, but all contained enough to meet the maintenance requirements of ruminants. Fruits from V. Karroo had higher (P<0.05) CP (182.26 g/kg DM), DM (896.50 g/kg DM) and ash (55.60 g/kg DM) contents compared to other browse species, while D. Lycioides fruits had higher (P<0.05) OM (951.60 g/kg DM) content than other browse fruits. Fruits harvested from G. Occidentalis had higher (P<0.05) ADF (513.27 g/kg DM), NDF (577.22 g/kg DM) and ADL (223.20 g/kg DM) content compared to other browse fruits. Fruits from V. Karroo had higher (P<0.05) CT (269.33 g/kg DM) content followed by Z. Mucronata (187.46 g/kg DM), while D. Lycioide (54.22 g/kg DM) and G. Occidentali (66.65 g/kg DM) had the same CT contents (P>0.05). There was a significant variation between browse species in macro and micro mineral contents. Fruits from G. Occindelis (43.93 g/kg DM) and V. Karroo (43.44 g/kg DM) had higher (P<0.05) Ca content compared to Z. Mucronata (24.06 g/kg DM) and D. Lycioides (20.06 g/kg DM). Ziziphus Muronata had higher (P<0.05) P (1.96 g/kg DM) content than other browse fruits. Fruits form V.karroo had higher Mg (4.75 g/kg DM), K (11.50 g/kg DM) and Na 3888 g/kg DM) content compared to other browse species. Fruits from V. Karroo showed significantly higher micro mineral content compared to other species. In terms of dry matter degradability (DMD), incubation time had an apparent effect on degradability of browse fruits except at 4 hours. The DM degradability increased with the increase of time and after 48 hours DMD was found to be satisfactory since it was above the prescribed 40 to 50 percent. However, the presence of condensed tannins had an effect on ruminal degradability of browse fruits. It was concluded that browse fruits have the potential to be used as protein supplements during the dry season since they contain moderate levels of crude protein. However, caution should be taken when feeding these browse fruits since they contain condensed tannins that affect rumen degradability. , Thesis (MSc) (Chemistry) -- University of Fort Hare, 2021
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Date Issued: 2020-01

Integration of nanostructured metal sulfides into titanium (iv) oxide for high performance dye sensitized solar cell

Authors: Agoro, Adedoyin Mojeed
Date: 2020-01
Subjects: Nanostructured materials , Sulfur compounds
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/21523 , vital:48857
Description: The work in this thesis describes synthesis, characterization and integration of nanostructured metal sulfides into titanium (IV) oxide for high performance dye sensitized solar cell. The synthesised single source precursors were evaluated using TGA, FTIR, , UV-Vis, PL,1H and 13CNMR, SEM, EDS, HRTEM, XRD, AFM, Raman, I-V, CV, Bode plot and EIS. TGA revealed the thermal degradation and quantified the mass percentage of metal sulphides as 33percent, 45percent and 27percent for CuS, PbS and SnS nanoparticles, respectively. FTIR analysis showed bands at 1580-1450 cm-1, and 1060-940 cm-1 tentatively assigned to C-N and C-S stretching frequencies correspondingly. The (M-S) stretching was observed at 577-406 cm-1 for the complexes using bis(N-di-isopropyl-N-octyldithiocarbamato) as primary ligands. IR spectra of bis(N-1,4-phenyl-N-(4-morpholinedithiocarbamato) as secondary ligands suggested the presence of (C-N) vibrations at 1508-1513 cm-1 for the complexes and 1507-1584 cm-1 for the ligands. The bands in the region of 973-1030 cm-1 were assigned to the complexes and 974- 983 cm-1 were attributed to the ligands, whereas vibration frequencies at 416-625 cm-1 were Nelson's Choice were included in these preliminary variety trials (PVTs) as checks. Twenty-five hybrids expressing high values for the Smith – Hazel selection index were identified across sites over years. Among those hybrids were two checks, namely Q16 (PAN5Q649R) and Q33 (Phb31MO7BR). The top five high – yielding hybrids selected based on the selection index were considered to be the most productive, stable and adaptable based on the GGE biplot and AMMI stability values. None of these single cross hybrids over yielded the best hybrid check (Q16) in the current study. A high potential environment, Centane, was the ideal environments for evaluating genotypes in the present study. The studies showed inbred lines L22, L23, L26, L28, L25, L29 and L31 to be low N stress tolerant at 0 kg N ha-1 based on the low N stress tolerance indices under glasshouse and the field conditions; they were also among the top ten grain-yielders under field conditions at 0 kg N ha-1. Also, in the NUE study, they were found to be among the top ten most N-efficient inbred lines under low N soils, under 30 kg N ha-1, and were among the top twenty-four inbred lines with high NUE values across the N levels in the study. Inbred lines L29 and L22 also produced testcross hybrids that were among the top twenty based on GY under 0 kg N ha-1. The testcross hybrids produced from these inbred lines were also among the top twenty-five with outstanding SCA effects for GY. These inbred lines were also parental lines of some of the top twenty- five best hybrids selected based on the Smith – Hazel selection index in the PVT study. Inbred lines L22, L23, L26, L28, L25, L29 and L31 can therefore further be evaluated and used as sources of N-tolerance genes in QPM breeding programs. tentatively assigned to M-S bond in the complexes. UV-Vis spectroscopy analysis for the complexes and from primary and secondary ligands are between within the range of 338 – 340 nm. PL studies of the primary ligands with metal complexes indicated emissions at 464 nm, 462 nm, 462 nm for Pb(II) and Sn(II), and Cu(II). The presence of secondary ligands was revealed by the absorption peaks at 455, 456 and 457 nm, exhibiting both the signals and chemical constituents of the respective ligands and their corresponding complexes. The electrochemistry in chapters 3 and 4 reveals that phase angle in the Bode plots changes with frequencies for Sn(II) complexes at 58, 57 and 8 respectively. Bode plots showed remarkable electronics of Cu(II) and Pb(II) complex interfaces. The CV curves exhibit two kinds of redox peaks indicating reduction at the negative potentials and oxidation at the positive potentials. The EIS, electrodes produced Rct for Pb(II), Cu(II) and Sn(II) electrodes in chapter 3. Moreover The EIS revealed that Sn(II) sensitizer displaced a stronger chemical capacitance and improved efficiency which could lead to better electron lifetime yield. The obtained CV exhibited anodic and cathodic peaks for Pb(II), connoting a reduction in Pb2+ and oxidation in Pb2-. Bode plot phase angle displayed Sn(II) and Pb(II) with maxima phase, indicating the presence of time constants of the electrode processes in Bis(N-1,4-Phenyl-N-Morhpo-dithiocarbamato bis(Mo/1,4-PHDTC) complexes. From the results in chapter 4, the XRD patterns exhibited good crystalline nature of CuS as a result of sharp and strong diffraction peaks obtained. There are eight peaks of 2θ angle between 26° and 79° relating to orthorhombic structure of SnS. While PbS has a cubic structure with polycrystalline nature, PbS/HDA and PbS both correspond to their crystalline planes of (200), (111), (220), (311), (222), (400), (331), (420) and (422) affirming to PbS QDs structure. SnS/HDA and SnS photosensitizers displayed eleven peaks between the values of 27.02° to 66.05° for SnS/HDA and 26.03° to 66.04° for SnS, in confirming the orthorhombic structure. SEM analysis revealed hexagonal structure for CuS, while PbS and SnS exhibited mesoporous nanostructures with spherical nanoparticles. HRTEM images indicated spherical nano-particles with particle sizes in the range of 3.14 - 44.39 nm. The outcome of HRTEM analysis revealed crystallite sizes varying as 10.90 – 11.57 nm, 3.14 – 5.95 nm and 14.96 – 44.39 nm for the CuS, PbS and SnS, originated from the primary ligands. HRTEM images originating from the Bis(N-1,4-Phenyl-N-Morhpo-dithiocarbamato bis(Mo/1,4-PHDTC) complexes indicated spherical nano-particles with particle sizes of 3.14 - 44.39 nm. Raman images in chapter 5 revealed the presence of Raman active modes of E2g 66 cm-1 and 304, cm-1 and E1g 627 cm-1 and 706 cm-1 for CuS, the active modes of TO 65 cm-1 and 2LO 626 cm-1 for PbS, active modes of B1g 69 cm-1 for SnS and 266 cm-1 for Ag. From the AFM results in chapter 5, CuS photosensitizer displayed a smooth surface and particle estimated to be 0.50 μm and height profile of 12percent. The PbS photosensitizer exhibited particle size of 1.82 μm and 0.654 μm for PbS/HDA, depicting a regular crystal growth rate. The size distribution of SnS nanoparticle at 357 nm connotes smooth surface and good compactness on the substrate. However, SnS/HDA at 122 nm displayed shape and size of non-symmetrical particles. AFM analysis in chapter 8 revealed good size roughness for CuS film. PbS exhibited particle size of 365 nm and size height of 18percent as the smoothest film, while PbS/HDA revealed 1.22 um size with 9percent size height. The evaluated particle sizes varied as 0.11- 1.18 um for SnS/HDA and 0.054 – 0.54 um for SnS films grown at 360 ℃ with size height of 16.8 and 8.4percent. The I-V efficiency obtained indicated that the CuS exhibited a much better efficiency in the QDSCs with higher Voc and the highest η being 2.85percent compared to CuS/HDA and Cu(II). High JSC of 11 mA/cm has been observed in the PbS/HDA QDSSCs, compared to the PbS and Pb(II) cells. The SnS/HDA exhibited a better performance compared to SnS and Sn(II) sensitizers due to the presence of HDA capping agent. , Thesis (MSc) -- Faculty of Science and Agriculture, 2020
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Date Issued: 2020-01

Investigating communal farmer’s perceptions on production practices and evaluating pre-slaughter responsiveness of extensively reared Boran and Nguni steers

Authors: Guzi, Anelisa https://orcid.org/0000-0001-5568-3396
Date: 2020-01
Subjects: Boran cattle , Nguni cattle , Cattle breeds
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10353/22721 , vital:52672
Description: This study's overall objective was to investigate communal farmers' perceptions on production practices and evaluate pre-slaughter responsiveness of extensively reared Boran and Nguni steers. On objective one farmers’ knowledge and perceptions on cattle breeds, management, and marketing channels in selected villages of Alice, Eastern Cape, South Africa were evaluated. Interviews were conducted using a structured questionnaire divided into demographic information and relevant cattle production practices, following a snowball technique to select 101 cattle-keeping households from Gaga, Ntselamanzi, and Ncerha villages. Most of the interviewed cattle farmers were males (65percent), in the age range of 40-60 years, with a primary-matric educational level. Among others, they highlighted financial security (47percent) and traditional ceremonies (26percent) as the reasons for keeping cattle. Most dominant in their herds were the Boran (49percent) and crossbreds (23percent) reared extensively with some supplementation (nutritional and medicinal). Their breed selection was based on disease and tick tolerance, temperament, and product (milk and meat) quality. It was noted that most of the interviewed cattle owners have the basic knowledge of good management practices, breed differences, and marketing chains. They related to low productivity to diseases, lack of knowledge, and poor resources. On the second objective pre-slaughter blood-based stress indicators and their subsequent effects were evaluated on beef quality of extensively reared Nguni and Boran steers . Twenty steers (10 Nguni and 10 Boran) aged 18 months were divided into two groups (with 5 of each breed per group) and transported from the University of Fort Hare Honeydale farm to the East London abattoir in the morning and afternoon trips. Upon arrival at the abattoir, the steers were held in lairage units for 24 hours (group 1) and 16 hours (group 2) until slaughter. Blood samples were drawn using a needle and vacutainer tubes from each steer's jugular vein at the farm before transportation, upon arrival at the abattoir, and during slaughter to perform cortisol, glucose, and routine haematological analysis. M. longissimus dorsi samples were harvested on the left side of each carcass to measure the meat quality attributes. Interactions between the observed production-stage activities, breeds, and physiological changes of these steers were recognized; with cortisol and glucose increasing (P ≤ 0.05) during transportation (4.15±0.46 ng/mL and 5.35±0.46nmol/L respectively) and also with farm group 1 showing higher cortisol (42.62±14.47 ng/mL) than the second group. Furthermore, all steers that were in slaughter group 1 showed less cortisol (101.49±14.47 ng/mL) and glucose (6.50±14.47 nmol/L) levels than those in group 2. In addition, Boran steers had higher packed cell volume, erythrocyte count, and haemoglobin values (33.27±0.54 percent, 7.66±0.19 106 μL, and 11.15±0.16 g/dl respectively) compared to Nguni steers in all production-stages. Later in the experiment, the effect of breed type, production stage activities (farm handling, transportation, and lairage duration), and stress responsiveness on some meat quality parameters (pH, lightness (L*), redness (a*), yellowness (b*), hue, Chroma, thawing and cooking loss, and tenderness) collected from the steers were measured. It was observed that the group lairaged for 16 hours produced the highest L* value (36.25±0.88) compared to those lairaged for 24 hours. As for the b* and hue of the meat, there were positive interactions between the breed type and the production stages (p<0.05). Lastly, cooking loss and tenderness were significantly affected by the breed type in all groups, with Nguni having the most tender meat (24.06±1.39 percent) and less cooking loss (16.92±1.33 percent) than Boran breeds. Therefore, the production stage conditions and breed type influenced some physiological stress-indicators and meat quality of Boran and Nguni steers raised on natural pastures. However, there were not many differences observed between the groups and breeds. , Thesis (MSc) -- Faculty of Science and Agriculture, 2020
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Date Issued: 2020-01

Cultivation, nutritional and pharmacological evaluation of Celosia argentea (L) Kuntze: an endangered wild vegetable in the Eastern Cape Province of South Africa

Authors: Adegbaju, Oluwafunmilayo Dorcas
Date: 2019-09
Subjects: Celosia , Edible greens
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/19806 , vital:43250
Description: Green leafy vegetables are important in human nutrition, but their cultivation is limited to a few staple ones. These vegetables possess high nutritious and therapeutic properties that could help in achieving nutritional security and alleviating the burden of some diseases. A typical example is Celosia argentea, which in South Africa, is little known and grossly under-utilized despite its numerous nutritional and pharmacological values. The present study investigated the cultivation, nutritional and pharmacological potentials of C. argentea at three stages of maturity of two trials. Evaluation of cultivation in the greenhouse towards possible domestication of C. argentea included seed viability test, seed germination under varying temperatures (5, 10, 15, 20 25 30, 35, 40°C), light conditions (continuous light, continuous darkness, alternating light and dark (12h light/12 dark photoperiod) and sowing depths (0, 1, 2, 3, 4 and 5cm). The nutritional evaluation assessed the proximal, mineral, vitamins and antinutrient content of the plant; while pharmacological potentials of C. argentea were evaluated by investigating the ultramorphology, phytochemical content, anti-oxidant, antimicrobial, toxicity and cell-based anti-inflammatory properties of the plant at different stages of growth. Germination experiment revealed that optimum seed germination requirements for C. argentea were 25°C, alternating light and dark regime and a sowing depth of 1cm. Microrphological assessment of C. argentea revealed that the leaves were amphistomatic; with the abaxial surface having higher stomata density. Characteristic, distinguishing protuberances were observed at the polar ends of the stomata on the adaxial surface of the plant epidermis, and the major elements on the foliar epidermis were beryllium, carbon, oxygen and potassium; while pigmentation and colouration, showing localization of bioactive compounds were mostly at the site where trichomes were abundant. Growth parameters and yield potential (plant height, stem girth, leaf area, number of leaves, number of branches, number of days to flowering, number of flowers as well as dry and fresh weight) of C. argentea showed that for agricultural practices on the field, increase in growth parameters should be expected around 4-5 weeks after transplanting while higher yield should be expected around 7-9 weeks after transplanting. The results encouraged cultivation during summer or late spring for best farm management. Proximal, mineral, vitamins and anti-nutrients content of C. argentea at three different maturity stages of two trials were performed using AOAC, ALASA and inductively coupled plasma-optical emission spectrometer techniques. Results revealed that the pre-flowering stage of growth had the highest ash (28.15± 0.10 percent) and crude protein (25.80 ± 0.20 percent) contents. While post-flowering stage had the highest carbohydrate (28.51± 0.20 percent and 36.16± 0.22 percent), crude fibre (33.41± 0.87 percent) and energy (435.28± 27.6 percent) with low fat and moisture (8.43± 0.15 percent and 6.35±0.09 percent) contents respectively; while no marked demarcation in most mineral contents in all the growth stages was observed. Zinc was highest at the flowering stage of growth, while vitamin contents decreased as the plant approached maturation. Antinutrients content of the plant was not dependent on growth stage. Total phenols, flavonoids and proanthocyanidin content of C. argentea were evaluated colourimetrically, while the antioxidant potency of the aqueous, acetone and methanolic extracts was measured using 2,2 diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), Ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) models. All the solvent extracts of the flowering stage had the highest total phenolic (80.75±4.21GAE/g), flavonoids (946.19±7.87QE/mg) and proanthocyanidin contents (100.90±1.29 CE/g); with the acetone extracts showing significantly higher phytochemical content. The flowering stage exhibited the best radical inhibitory activity, with the methanol extract having the highest scavenging power for ABTS and DPPH radicals, while acetone extract showed the highest inhibition against FRAP and highest total antioxidant capacity. The antimicrobial potential of the aqueous acetone and methanolic extracts of C. argentea evaluated using agar dilution method against six bacteria (Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Bacillus cereus) and four fungal strains (Candida glabarata, Candida albicans and Penicillium aurantiogriseum and Penicillium chrysogenum) showed that Streptococcus pyrogenes and P. aeruginosa were susceptible to the methanol extracts of all the growing phases of both trials at 10 mg/mL; while Klebsiella pneumoniae was susceptible at 10 mg/mL to only the methanol post-flowering extracts of both trials. C. albicans and P. aurantiogriseum were highly susceptible to all the extracts. Possible toxicity evaluated using brine shrimp lethality assay and calculation of LC50 against brine shrimp nauplii revealed that C. argentea was not toxic at any stage of maturity at all concentrations evaluated. Anti-inflammatory activities and cytotoxicity of C. argentea extracts evaluated using RAW 264.7 macrophages and 3T3-L1 cell lines revealed that the acetone extract of the flowering stage had moderate anti-inflammatory activity with no significant toxicity against activated macrophages. Findings from this study indicate that C. argentea is a safe functional leafy vegetable of high nutritional and pharmacological importance which can easily be cultivated and domesticated in South Africa. This could significantly alleviate the burden of micronutrient deficiencies among pre-school children in rural communities. , Thesis (PhD) (Botany) -- University of Fort Hare, 2019
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Date Issued: 2019-09

Studies on vine storage methods, planting techniques, paclobutrazol treatment, planting density and weevil management on sweetpotato (ipomoea batatas l.lam) cultivars promoted in South Africa

Authors: Hlerema, Igenicious Nicholas https://orcid.org/0000-0002-6111-404X
Date: 2019-09
Subjects: Sweet potatoes , Seed treatment
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/21580 , vital:49336
Description: Sweetpotato (Ipomoea batatas L. LAM) is a major world staple food. It is a versatile, nutrient-rich crop well suited for production by emerging farmers, and thus a popular crop in subtropical parts of South Africa. The crop has several advantages such as producing more bioweight and nutrients per unit land area and per unit time than most other staple crops such as maize; adaptation to a broad range of agro-ecological conditions; and ability to compete and crowd out weeds, and affected by a relatively small number of pests and diseases. Root and vine yields achieved by emerging farmers are low and cultivation systems need to be optimized. The general objective of the research was to develop nursery practices that ensure a sustainable supply of sweetpotato planting materials and cultural practices that maximize yield, eating and nutritional quality of sweetpotato roots. The specific objectives were (i) to evaluate the effect of polyethylene and hessian bags on vine quality and vine survival period; (ii) to compare planting techniques and vine length; (iii) to determine the effect of paclobutrazol on storage root yield; and (iv) to evaluate the effect of Beauveria bassiana as biological control for sweetpotato weevil. The vine storage experiment aimed at identifying the best type of storage bags that keep the vines of “Bophelo”, an orange-fleshed sweetpotato cultivar in good quality for a longer period of time. The study involved two factors, viz storage bag type and storage period. The experiment tried to address (1) a sustainable seed system in sweetpotato and (2) production stimulated by cultural practises. Vines were stored in polyethylene bag without holes, polyethylene bag with 12 holes and dry hessian bag over 3, 6, 9, 12 and 15 days at an ambient temperature of 250C. The incremental cost-effectiveness ratio (ICER) was calculated to determine the cost-effectiveness of using the polyethylene bags with holes or without and the hessian bags. The results of the study showed that hessian bags store vines over a longer period (12 days) compared to the polyethylene bags without holes (6 days); however, hessian bags are more expensive. Polyethylene bags can still be used for transporting and storing vines if the farmer is within a short distance from the seed source and plants the vines within the 6 day period. Polyethylene bags with 12 holes are recommended since they allow maximum air circulation and extend storage period (9 days). Optimum planting techniques can help sweetpotato farmers to achieve optimal yields. Newly developed cultivars from the Agricultural Research Council have not been tested to determine the best planting techniques. A trial was conducted to investigate the effect of two planting orientations (horizontal and vertical) and different vine length (2, 3 and 4 subterranean nodes) of 3 released varieties, Blesbock, Bophelo and Ndou on storage root yield of sweetpotato. A factorial experiment was laid out in a randomised complete block design with three replications during two cropping seasons (2014/15 and 2015/16). The data collected in both experiments included total storage root yield, marketable storage root yield, and number of storage roots per size class. Significant differences were detected for the interaction of all factors on the number roots per size class, total storage root yield, and total average root weight. Vertical and horizontal planting per se showed no significance differences for all the sweetpotato root growth parameters such as total yield. However, the more the number of subterainian node the more yield we got for the commercial cultivar Blesbok. Paclobutrazol (PBZ) is a plant growth retardant hormone. This hormone might, therefore, be useful for sweetpotato growers to achieve higher plant populations per hectare because it would reduce the plant canopy. However, it should also be checked if the PBZ application does not affect nutrient content of roots and leaves, especially the beta-carotene content of the orange-fleshed cultivars. The objective of this study was, therefore, to determine the effect of PBZ on sweetpotato shoot growth, storage root yield and beta-carotene content of sweetpotato leaves and storage roots. The field trial was repeated over two seasons, namely 2014/15 and 2015/16 crop seasons. These field experiments were arranged as a split plot experiment. The main plots were allocated to four PBZ levels, laid-out as randomised complete block design, and treatment combinations of two cultivars (Bophelo and Blesbok) and two plants spacing (20 cm and 30 cm) were randomly allocated into the subplots. The PBZ levels applied were 0, 100, 200 and 300 mg of active ingredient per litre of water, sprayed 4 weeks after planting. Root yield and bioweight accumulation were recorded. In addition, a pot experiment was set up using cultivar Bophelo and 0 mg, 100 mg and 200 mg/l active ingredient of PBZ sprayed 4 weeks after planting. Leaf and root samples (150g and 400g of a composite sample respectively) were collected and analysed for total phenols, total flavonoids, vitamin C and beta-carotene. The field trial results revealed significant differences (P<0.05) in leaf and stem weight of the plants treated with different PBZ levels applied. The control (0 mg PBZ rate) had the highest leaf and stem weight. There were no significant differences in root yield among the PBZ levels. The results of leaf and root analysis for the Bophelo cultivar showed significant differences (P<0.05) in total phenols, total flavonoids, vitamin C and beta-carotene in leaf samples of the three levels of PBZ applied. The beta-carotene for the leaf increased at the 100 mg/l PBZ level. As the paclobutrazol level increased there was a reduction in the beta-carotene content for the roots from 18,91 to 13,97 to 10,77 mg/100g dry weight for 0 mg/l, 100 mg/l and 200mg/l, respectively. Application of PBZ to sweetpotato reduces the bioweight yield but does not have an effect on the root yield. Thus a higher plant density can be used to achieve higher yield and returns on investment. The leaves can be used as a relish and can be sold to supplement income. However, PBZ further reduces the beta-carotene content of the roots and is not recommended for use with orange-fleshed cultivars, where the objective is to enrich food with vitamin A. Sweetpotato weevils (Cylas puncticollis and C. formicarius) are notorious pests of sweetpotato. It causes severe losses in marketable root yield. The study tested the use of Beauveria bassiana (Balsamo Vuillemin) (Deuteromycota: Hyphomycetes) for controlling sweetpotato weevils. Experiments were conducted over two cropping seasons using four treatments: 1) dipping sweetpotato cuttings in solution of 1 g/litre B. bassiana before planting, 2) spraying with a registered chemical (Deltametrin) at 50 ml/100 litre of water starting 2 weeks after panting at biweekly basis for four months after planting, 3) spraying the leaves with B. bassiana (10 g/100 litre) starting 2 weeks on biweekly basis for four months after planting; and 4) control (sprayed with water). The research was arranged as split plot experiment, where the pest management treatments assigned to the main plots as per Latin square design and the three sweetpotato cultivars (Bophelo, Ndou and Blesbok) were randomly put in the subplot in each main plot. Spraying with B. bassiana significantly reduced the percentage of insect-damaged roots (9.95percent) compared to the control (22.48percent). Dipping sweetpotato cuttings in solution of 1 g/litre B. bassiana before planting did not significantly reduce the number of insect damaged roots (18.63percent insect damage). There was no significant difference between the chemical spray (8.2percent insect damage) and spraying with B. bassiana (9.95percent insect damage). The investigation indicated that B. bassiana can be considered as an alternative control method for the sweetpotato weevil. Use of biological control is less expensive and beneficial to reduce adverse effects on the environment and human health. , Thesis (PhD) -- Faculty of Science and Agriculture, 2019
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Date Issued: 2019-09

Surveillance study on pathogenic Acinetobacter species in freshwater environment of the Amathole and Chris Hani District Municipalities, Eastern Cape, South Africa

Authors: Adewoyin, Mary Ayobami
Date: 2019-09
Subjects: Acinetobacter infections , Acinetobacter , Nosocomial infections
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/19836 , vital:43257
Description: This study evaluates the occurrence of medically relevant Acinetobacter species in three rivers, namely; Keiskamma, Tyhume and Great Fish in the Eastern Cape Province, South Africa in one year sampling regime (April 2017 - March 2018). The physicochemical parameters (pH, temperature (TEM), electrical conductivity (EC), total dissolved solids (TDS), salinity (SAL), total suspended solids (TSS), turbidity (TBS), dissolved oxygen (DO) and biological oxygen demand (BOD)) of the water bodies were measured. The presumptive Acinetobacter species recovered from the freshwater resources were recorded and further confirmed using molecular techniques. Similarly, confirmed isolates were subjected to speciation using species-specific primer sets for A. baumannii and A. nosocomialis. Also, virulence genes namely; afa/draBC, epsA, fimH, OmpA, PAI, sfa/focDE, and traT in the two Acinetobacter species were also determined using molecular method. In addition, the antibiogram characteristics of A. baumannii and A. nosocomialis isolated from the water samples were determined using standard methods. The antibiotic susceptibility test was performed using a panel of 12 antibiotics belonging to the aminoglycosides (amikacin, AK and gentamicin, GM), β-lactam/β-lactamase-inhibitor combinations (piperacillin-tazobactam, PTZ), cephems (ceftazidime, CAZ, cefotaxime, CTX, and cefepime, CPM), carbapenems (imipenem, IMI and meropenem, MEM), fluoroquinolones (ciprofloxacin, CIP), folate pathway inhibitors (Trimethoprim/sulfamethoxazole, TS), lipopeptides (Polymyxin B, PB) and tetracyclines (tetracycline, TET). Similarly, antibiotic resistance genes (ARGs) present in the Acinetobacter isolates were investigated including aminoglycoside resistance genes (aacC2, aphA1 and aphA2), β-lactamases resistance genes (blaTEM, blaSHV, blaOXA-1-like, blaCTX-M(GROUP 1), blaCTX-M(GROUP 2), blaCTX-M(GROUP 9), blaVEB, blaGES, blaPER, blaCTX-M-8/-25, blaOXA-48-like, blaVIM, blaIMP and blaKPC), fluoroquinolones resistance genes (qnrA, qnrB, qnrC, qnrD and qnrS), sulfonamide resistance genes (sul1 and sul2), and tetracycline resistance genes (tetA, tetB, tetC, tetM, tetL and tetO). The pH, EC, TDS, SAL, TEMP, TSS, TBS, DO, and BOD for Tyhume River ranged as follows: 7.2-7.7, 125-141 μS/cm, 62-71mg/L, 0.06- 0.07 PSU, 11.3-20.2oC, 30.0-89.6 mg/L, 35.0-96.0 NTU, 8.2-9.8 mg/L, 2.0-4.2 mg/L, while for Great Fish River, the parameters were 8.0-8.2, 274-369 μS/cm, 137-184mg/L, 0.13-0.18PSU, 12.7-22.3oC, 44.3-99.4 mg/L, 48.0-214.0 NTU, 7.8-9.9 mg/L, 3.1- 4.9 mg/L, and at Keiskamma River they were 7.5-7.9, 153.2-285.0 μS/cm, 86-143 mg/L, 0.07-0.14 PSU, 11.0-21.4oC, 27.0- 55.6 mg/L, 31-61 NTU, 8.3-9.8 mg/L, 3.0-6.0 mg/L. A total of 1107 presumptive Acinetobacter spp. were recovered from the rivers sampled of which 428, 370 and 309 isolates were recovered from Tyhume, Great Fish and Keiskamma rivers respectively. However, only 844 was confirmed positive for the genus Acinetobacter and are recovered in the proportions 285 (77 percent), 219 (70.9 percent) and 340 (79 percent) from Great Fish, Keiskemma and Tyhume rivers respectively. Our finding revealed that 410 (48.58 percent) and 23 (2.7 percent) of the isolates were confirmed to be A. baumannii and A. nosocomalis respectively. Also, 308 (75.12 percent percent) A. baumannii and 3 (13.04 percent) A. nosocomialis isolates exhibited one or more virulence genes out of the seven tested, whereas 102 (24.88 percent) and 20 (86.95 percent) of the A. baumannii and A. nosocomialis isolates did not harbour any virulence gene. Additionally, OmpA was the most prevalent (p<0.05) virulence gene found in A. baumannii with 69 (45.10 percent), 52 (50.98 percent) and 77 (49.68 percent) isolates from Great Fish, Keiskamma and Tyhume rivers respectively. The rates of susceptibilities of A. baumannii and A. nosocomialis to the antibiotics followed the order; Piperacillin-tazobactam (72.8 percent ; 73.9 percent), Ceftazidime (70.5 percent ; 91.3 percent), Cefotaxime (16.8 percent ; 17.4 percent), Cefepime (88.5 percent ; 95.7 percent), Imipenem (95.9 percent ; 100 percent ), Meropenem (92.7 percent ; 91.3 percent), Amikacin (97.6 percent ; 91.3 percent), Gentamicin (89.8 percent ; 87 percent), Polymyxin B (84.4 percent ; 91.3 percent), Tetracycline (74.7 percent ; 78.3 percent), Ciprofloxacin (75.9 percent ; 78.3 percent) and Trimethoprim/sulfamethoxazole (74.0 percent ; 73.9 percent) respectively. Both A. baumannii and A. nosocomialis were highly susceptible to all the antimicrobials tested except cefotaxime where 64 percent and 78 percent intermediate responses were observed in the species. At least 10 isolates of A. baumannii were resistant against each of the antibiotics used. The modal multiple antibiotics resistance phenotypes (MARPs) for Acinetobacter spp. was MARP 3 (29.87 percent) and the least was MARP 10 and 11 (2.6 percent each). The antimicrobial resistance index (ARI) was higher at two sampling sites KE2 (0.33) and TY1 (0.22). Similarly, MARI showed that sampling sites KE2 was a hotspot for multidrug-resistant Acinetobacter spp. Of the five classes of ARGs studied, there was a widespread of β-lactamases (blaTEM) in the two Acinetobacter species, followed by sul2, which were detected in 67 (63.2 percent) and 44 (49.4 percent) isolates respectively, across the rivers studied. We conclude that aquatic resources of the study community are important reservoirs of pathogenic Acinetobacter species and antibiotic resistance determinants. The occurrence of clinically-important Acinetobacter species suggests possible contamination of these selected rivers which are consumed by humans and livestock, as well as being used for irrigation system, and this constitutes a risk to public health. It also shows that A. baumannii and A. nosocomialis can thrive in the aquatic environment. This study suggests that direct utilization of water from these sources for domestic and other purposes without any form of pre-treatment should be avoided. It is, therefore, necessary for regulatory authorities to monitor the release of domestic and industrial wastewater into these water bodies in order to prevent outbreaks of epidemics. , Thesis (PhD) (Microbiology) -- University of Fort Hare, 2019
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Date Issued: 2019-09

Profitability and technical efficiency of small-scale organic crop farmers’ in the Eastern Cape Province of South Africa

Authors: Eyinade, Gabriel A https://orcid.org/0000-0001-8851-7255
Date: 2019-08
Subjects: Organic farming , Farms, Small
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/23633 , vital:58229
Description: Organic farming is growing gradually in South Africa. Its contribution to economic growth and poverty mitigation is notably in the pastoral areas in terms of providing adequate and affordable food for the incessantly growing population. Organic farming is also known for provision of employment and source of livelihoods for the rural populace as well as supply of raw materials to the country’s agro-allied industrial sector. For the purposes of this research, focus was only on profitability and technical efficiency because it is an essential subject in developing agriculture where resources are limited, but high population growth is very common. As a result, increased output will rely more on efficiency enhancements which will further intensify farmers’ income. As such, evaluating the extent for such efficiency enhancements within the system is a crucial prerequisite. The objective of the study was to assess the profitability and technical efficiency; and to identify socio-economic, institutional and farm characteristics that influence profitability and the technical efficiency of the small-scale organic crop farmers in the Buffalo City Metropolitan Municipality (BCMM). A purposive sampling technique was used to collect primary data from 160 small-scale organic crop farmers in BCMM. The gross margin estimation was used to estimate profitability, while multivariate Ordinary Least Square (OLS) was used to assess socio-demographic factors influencing profitability. The stochastic frontier model was used to determine the level of technical efficiency as well as the determinants of technical inefficiency of the farmers. The results of the gross margin estimation show that the small-scale organic maize (GM= R392 417.00) and cabbage (R196 489.00) farms were profitable. Similarly, the results of the OLS showed that one out of the eight variables namely, farming experience influences organic maize producers’ profitability, while factors such as gender, household size, and educational level emerged as the major significant factors influencing organic cabbage producers’ profitability. The stochastic results revealed that small-scale organic crop farmers in the study area are technically efficient at 86percent in maize production and 93percent in cabbage production respectively; and experienced unity return to scale (1.0) in maize and increasing return to scale (1.2) in cabbage. The results suggested that an increase in the use of input, would also intensify their productivity and efficiency. The results from the inefficiecncy model of the stochastic frontier further show that age and farming experience are the major determinants of organic maize producers’ technical inefficiency, while, factors such as age, years of schooling, farming experience, and household size were the significant determinants of organic cabbage producers’ technical inefficiency. To enhance the farming potential of these farmers, it is recommended that government and other several stakeholders such as researchers, entrepreneurs should invest more in organic crop farms since it is profitable and efficient in improving farmers’ livelihoods. There is also need for government to organise on-going workshops and extension training through the help of extension officers on how farmers can improve their production which will further enhance their income. , Thesis (PhD) -- Faculty of Science and Agriculture, 2019
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Date Issued: 2019-08

A comparative analysis of mobile application development frameworks: A case study of mobile application development for water usage management in Alice and Fort Beaufort communities

Authors: Manu, Kwabena
Date: 2019
Subjects: Mobile communication systems Cell phones Cloud computing
Language: English
Type: Thesis , Masters , MSc. (Computer Science)
Identifier: http://hdl.handle.net/10353/14130 , vital:39853
Description: Mobile phones have become an integral part of standard of living. Users and customers expect sensible and very useful applications in less time. In this competitive market, it is an enormous challenge to develop high performance mobile applications that might meet the expectations of end users. Despite the fact that development of new applications for each mobile operating system in short time is fairly an issue, mobile operating systems vendors are giving their best available resources for creating applications in additional convenient ways. These days, there is a common tendency to look for less complex and quicker solutions that could be used in the process of software development. Developers of a new mobile application have to undertake variety of selections and decisions, including the target platform as well as the development technology to utilize. Mobile application development frameworks contribute in solving this problem. Several frameworks have emerged, which we classify and evaluate their appropriateness. In order to compare existing development frameworks solutions in this research, we compiled a set of criteria to assess mobile application development approaches. In view on these criteria, we evaluated five frameworks that is, PhoneGap, Xamarin, App Inventor, Sencha Touch and DragonRad. For proof of concepts, the chosen framework from the five evaluated mobile development frameworks was used to develop application for water usage management. The research will equip mobile application developers to gain more insight into mobile development frameworks available, therefore helping them to choose the most appropriate framework for their project.
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Date Issued: 2019

A Model for Intrusion Detection in IoT using Machine Learning

Authors: Nkala, Junior Ruddy
Date: 2019
Subjects: Internet of things
Language: English
Type: Thesis , Masters , MSc (Computer Science )
Identifier: http://hdl.handle.net/10353/17180 , vital:40863
Description: The Internet of Things is an open and comprehensive global network of intelligent objects that have the capacity to auto-organize, share information, data and resources. There are currently over a billion devices connected to the Internet, and this number increases by the day. While these devices make our life easier, safer and healthier, they are expanding the number of attack targets vulnerable to cyber-attacks from potential hackers and malicious software. Therefore, protecting these devices from adversaries and unauthorized access and modification is very important. The purpose of this study is to develop a secure lightweight intrusion and anomaly detection model for IoT to help detect threats in the environment. We propose the use of data mining and machine learning algorithms as a classification technique for detecting abnormal or malicious traffic transmitted between devices due to potential attacks such as DoS, Man-In-Middle and Flooding attacks at the application level. This study makes use of two robust machine learning algorithms, namely the C4.5 Decision Trees and K-means clustering to develop an anomaly detection model. MATLAB Math Simulator was used for implementation. The study conducts a series of experiments in detecting abnormal data and normal data in a dataset that contains gas concentration readings from a number of sensors deployed in an Italian city over a year. Thereafter we examined the classification performance in terms of accuracy of our proposed anomaly detection model. Results drawn from the experiments conducted indicate that the size of the training sample improves classification ability of the proposed model. Our findings noted that the choice of discretization algorithm does matter in the quest for optimal classification performance. The proposed model proved accurate in detecting anomalies in IoT, and classifying between normal and abnormal data. The proposed model has a classification accuracy of 96.51% which proved to be higher compared to other algorithms such as the Naïve Bayes. The model proved to be lightweight and efficient in-terms of being faster at training and testing as compared to Artificial Neural Networks. The conclusions drawn from this research are a perspective from a novice machine learning researcher with valuable recommendations that ensure optimal classification of normal and abnormal IoT data.
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Date Issued: 2019

Aeolian processes and landforms at Mesrug on sub-Antarctic Marion Island

Authors: Nguna, Abuyiselwe Athandile
Date: 2019
Subjects: Eolian processes Sediments (Geology)
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/17095 , vital:40848
Description: Recent observations have recognised the increasing role of aeolian processes as a geomorphic agent on sub-Antarctic Marion Island. This study presents the first long-term data on aeolian processes and dynamics at Mesrug (46° 56’ 41”S; 37° 49’ 59”E) on subAntarctic Marion Island. An intensive and high-resolution (five-minute interval) environmental monitoring campaign was initiated using Pace Scientific XR5 data loggers while aeolian transported sediments were collected using Big Spring Number Eight (BSNE) sediment traps at four different heights above the ground. The aeolian features at Mesrug is identified as mega-ripples and is essentially an erosional feature, while annual sediment flux at 0.05 m height were calculated as 2.29 kg cm-2 y -1 . Spatial data based on a two-year survey showed that the entire surface of the study area have lowered by deflation while the ripples shifted slightly eastward (down-wind). Furthermore, the site lost 3.4 m3 of sediment between these two surveys with an average of 0.75 cm per 1 m2 across the site which has an area of 454 m2 . The study suggest that the relatively large particle size of surface sediments on Marion Island is a major contributor to the low annual aeolian sediment flux. From the AWS data it is clear that high wind speeds are frequent at Mesrug and the high wind speeds facilitating sediment movement. Sediment supply is the limiting factor of aeolian sediment transport, but even though the perennial wetness experienced on the island is not a major limiting factor to sediment flux, it may influence rate of movement. The predominant wind direction at the study site is from the south-west but maximum wind velocities are from the north-west. The data from the wind-aspirated BSNE sediment traps, indicate that sediment movement occurs closest to the surface and weight of sediment moved as well as size of particles decreases vertically in the air column. It seems that the upper limit of aeolian sediment transport at Mesrug is 0.8 m above the ground and saltation of particles is the dominant aeolian transport mechanism. Sediment movement occur in near gale to gale force winds and horizontal precipitation. This is mainly associated with strong north-westerly winds which are linked to a frontal system from a mid-latitudinal cyclone that has a strong meridional component or is a cut of low pressure. The data suggest that the climate change implication of a reduction in the westerly component of wind could reduce wind speeds and this could influence the magnitude and frequency of aeolian sediment transport on Marion Island in the future
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Date Issued: 2019

Amaranth (Amaranthus cruentus) growth and nutritional contents as affected by nitrogen and potassium fertiliser and plant density

Authors: Mamvura, Luckmore
Date: 2019
Subjects: Weeds -- Control -- Management
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/17249 , vital:40869
Description: The research was conducted to determine the response of amaranth growth and development to different rates of nitrogen and potassium fertilizer, the effect of plant density on herbage yield and weed management, effect of leaf age and stems on nutritional value of amaranths. The research was conducted at the University of Fort Hare Research Farm and University of Fort Hare glasshouse. For the fertilizer trial, a 4 x 3 factorial experiment: nitrogen at four levels (50kg/ha; 100kg/ha; 150kg/ha; 200kg/ha) and potassium at three levels (50kg/ha; 75kg/ha; 100kg/ha) was applied. Phosphorus was applied at 50kg/ha. The experiment was laid as randomised complete block design (RCBD) with 4 blocks (replication). The results showed that application of nitrogen and potassium treatments significantly (P < 0.05) increased plant height, stem girth and number of leaves per plant which in turn increased the crop economic leaf vegetative yield. The results also showed that at high rates of nitrogen and potassium, high vegetative yields were achieved in most cases. There was no interaction (P < 0.05) between nitrogen and potassium. Second experiment, the twelve treatments used in fertilizer trial were imposed under four different amaranth plant densities (1 200 000, 1400 000, 1600 000 and 1800 000 pph) at field level to find out growth and development performance of amaranth. In addition, at the same time investigating the effectiveness of plant density on weeds management using split plot design. The different planting densities were allocated to the main plots laid-out in RCBD. The results showed that there was no significant difference (P < 0.05) on the number of weeds under four plant densities. The results showed that different plant densities did not prevent weeds germination but the amaranths tolerate the negative effects of weeds. The nutritional analysis results showed that amaranth synthesised close to above recommended nutritional level despite different treatments applied. The third experiment: stems, lower and upper leaves were harvested separately and their nutritional composition was analysed. The results showed that the nutritional composition of stems, lower leaves and upper leaves were significantly different (P < 0.05) in most cases. Lower leaves dominated nutritional content for: crude protein crude fibre, carbohydrates, and calcium. The stems recorded least nutritional content on crude protein, crude fat, carbohydrates, calcium, potassium and sodium
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Date Issued: 2019

An Assessment of the Environmental Impacts of Urban Sprawl in Buffalo City Metropolitan Municipality, Eastern Cape Province

Authors: Matiza, Collins
Date: 2019
Subjects: Cities and towns -- Growth -- Environmental aspects City planning
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/17260 , vital:40870
Description: Large industrial and residential developments near towns and along highways associated with public policies have transformed the pattern of development over the recent years, creating a new urbanisation phenomenon; urban sprawl. Indiscriminate population densities, discontinuous and fragmented settlements, largely define urban sprawl. The progression of urban sprawl can be described by transformation in pattern over time, like proportional increase in built-up surface to population leading to rapid urban spatial expansion. Stemming an understanding from the processes, causes and patterns of urban sprawl, the consequences of sprawl on land and vegetation can be analysed. Environmental impacts to both the rural and urban population emanate from such instances, creating an excessive liability to the government. With attention to this and recognising the lack of discussion on the matter, the research deliberates some of the impacts observed in Buffalo City Metropolitan Municipality, Eastern Cape, South Africa. The study makes use of Geographic Information Systems and Remote Sensing with the assistance of landscape metrics. The influence of urban sprawl in this municipality has revealed impacts on vegetation, green areas and land in general. The results disclose that urban sprawl is a multidimensional phenomenon that is better explained using various methods (indices). Buffalo City Metropolitan municipality is located in Eastern Cape amidst the thicket ecosystem, the municipality has grown and expanded over the recent past. The study spread over an 18-year period from 1994- 2012. Based on field surveys and SPOT imagery, built-up areas of BCMM was extracted for different periods. Data used for the study are census data for BCMM, 1994, 2000, 2006 and 2012 SPOT images, images of BCMM acquired from Google earth 2018. The rate of transformation of the area was calculated and it was higher compared to that of population growth. Based on this data urban growth are analysed with the assistance of landscape metrics that include Shannon entropy. The outcomes confirm that this metropolitan municipality has experienced sprawl and sprawl has done so at cumulative rate.
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Date Issued: 2019

Analyses of Retail and Transport Geography of Liquefied Petroleum Products in Ibadan metropolis, Nigeria

Authors: Ajayi, Adeyinka Peter
Date: 2019
Subjects: Petroleum products
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10353/19065 , vital:40090
Description: This study analyzed the effects that spatial arrangement of petroleum products retail outlets and the supply chain management techniques employed for products distribution (for both intra city and intercity shipments) have on the retailing dynamism of petroleum products within built environment and peripherals of Ibadan metropolis over the years. Specifically, the study investigated the differentials in the spatial configurations of petroleum products retail outlets between the core and periurban zones of the metropolis. An attempt was made to determine the explanatory variables that influence the spatial distributional decisions of petroleum products retail outlets in the metropolis. The study equally examined how the supply chain management (SCM) techniques by the different categories of the retail outlet owners influence the efficient and cost effective distribution of petroleum products. Lastly an attempt was made to analyze the relationship between the socio-economic attributes of the haulers and the achievement of compliance to the HSE stipulations guiding the conveyance of petroleum products. The theoretical underpinnings for the research were a derivative of the amalgamation of normative and psychological theories from geography, psychology, SCM and retailing science. Specifically, Expectation Disconfirmation Theory (EDT), Distributive Justice, Central Place Theory (CPT) Theories of Urban Impact (TUI) and Theory of Constraint (ToC) were the theories utilized in the study. For the achievement of the first objective which was to investigate the possible differential in the compliance rate between spatial pattern of fuel retail outlets in the core and peripheral zones of Ibadan metropolis, the first hypothesis of the study (which examined if there was no significant difference in the rate of compliance to the planning authority stipulations guiding the location pattern of petroleum product retail outlets between those located in the built up and xxiv peripheral zones of the city), was tested through the use of buffering and proximity analyses in the ArcMap environment of ArcGIS 10.1, while inferential statistical tool of an independent-samples t-test was conducted to compare the rate of compliance to the stipulations guiding the locations of these outlets in both the core and the peripheral zones. The result from the GIS analysis indicated that 33 (15.56%) out of the 220 outlets in the core zone of the metropolis complied with the planning stipulations guiding the location of fuel retail outlets. For the peripheral zone, out of the 220 fuel retail outlets 24 (10.90%) complied with the stipulations. The result from the t- test which was employed to test the hypothesis indicated that no significant difference existed in the rate of compliance t (263) =-2.66, p = 0.08 between fuel retail outlets in the core zone (M=3.9, SD=1.4) and peripheral zone (M=4.5, SD=1.79). The alternate hypothesis which stated that ―no significant difference existed in the compliance rate between fuel retail outlets located in the two zones‖ is accepted. For the achievement of the second objective of the study which was to analyze the factors which determine the location of fuel retail outlets both in the core and peripheral zones of Ibadan metropolis. All the managers/owners of the 432 fuel retail outlets in the metropolis were sampled out of which 256 questionnaires were retrieved for the purpose of this analysis. The breakdown of the socio-economic characteristics of the sampled respondents showed that the gender distribution showed that 194 (75.78%) of the respondents were males, while 64 (24.22 %) were females. The average age of the sampled population was 33.70 years. The mixed method was employed for the achievement of the second objective of this study. Logistic Regression Model (LRM) was employed to test the hypothesis and the result revealed that the inclusion of the independent variables in the model increased the overall level of it accuracy. The overall significance revealed that the Model Chi- xxv Square, derived from the likelihood fitted is also accurate (X2 = 43.47, df=5, p>.05). The model chi-square value of 43.47 (approximately 44% ) was significant. Thus, the indication is that the model has a good fit in predicting the possibility of a fuel retail outlet being located in the core or peripheral zone of the metropolis as determined by the explanatory variables (the independent variables accounted for about 44% of possible factors which determined whether a fuel retail outlets is located either within the core or peripheral zones of the metropolis. The remaining 56% are factors not considered in the study). The result gotten from the in depth interview sessions corroborated the findings from the tested hypothesis. The third objective was to examine the effects which the supply chain technique employed (either vertically integrated model or third-party arrangement) has on the achievement of efficient and effective distribution of the products. In order to achieve this objective, all the 389 registered members of Petroleum Tanker Drivers (PTD) association who are members of the PTD in the metropolis were sampled, 265 (around 70%) of the distributed questionnaires were retrieved and used for the analysis. In depth interview sessions were also conducted with three different managers of the three major conglomerates in the downstream sector of the Nigerian petroleum sector. The result of one-way between subjects (ANOVA) which was conducted to compare differences in the management and performances of haulage services outsourced to the 3PLS and those run under VIM showed that there was a significant effect of ownership type on management performance (F (2,262) = 60.26, p<.05). The null hypothesis was therefore rejected while the alternate hypothesis was accepted. The findings from the interview sessions posted similar results. The fourth and final objective was to analyze the effect that the socio-economic attributes of the participants (haulers and managers of retail outlets) involved in the distribution of xxvi petroleum products has on the safe, efficient and cost-effective distribution of product and this was done through the use of descriptive statistics, inferential statistics and incisive analysis of the interview sessions. A total number of 265 (70%) out of the 389 registered members of Petroleum Tanker Driver Association (PTDA) participated in the study. Multiple regression analysis (MRA) was used to test this hypothesis. The result from the statistical analysis show that the use of stimulant, work condition, marital status and educational attainment/literacy level have joint influence on compliance (R2 = 0.31, F (4,260) = 29.72, p<.05). On the basis of the foregoing, the hypothesis is thus accepted. The result from the interview sessions confirmed the existence of strong relationship between the explanatory variables and the hypothetical dependant variable. The study recommended a review of the planning processes guiding the establishment of fuel retail outlets. The study also advocated that retailers should endeavour to have stronger control over the supply chain of their products this could done by investing more in VIM rather than outsourcing such functions to 3PLs. This will help in better business performances. Government agencies in charge of monitoring drug abuse among haulers are advised to be more proactive by the duo of prevention and punishment strategies. This should include advocacy campaign against drug abuse. Different ranges of punishments should also be meted out for individual haulers found culpable.
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Date Issued: 2019

Application of some missing data techniques in estimating missing data in high blood pressure covariates

Authors: Odeyemi, A. S
Date: 2019
Subjects: Missing observations (Statistics) Hypertension
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10353/15189 , vital:40195
Description: Cases recorded with high blood pressure are a major concern in both public and private hospitals. Adequate provision of health information of patients relating to high blood pressure in Eastern Cape Hospitals hinges so much on the outcome of statistical analysis results. The usual statistical methodologies become inadequate in handling statistical analysis of data collected due to incomplete patients’ information stored in the hospital database. From time to time, new methods are developed to address the problem of missing data. High blood pressure is linked to a lot of diseases such hypertension, cardiovascular disease, kidney disease and stroke. In this study, we developed a new method for addressing the problem of missing data in assessing model used for estimating missing values in terms of minimum errors(using RMSE, MAE, and SE) and goodness-of-fits(using 2 R and adjusted 2 R ) of this model and P-value. . The study compared six different methods: Original data (OD), Listwise deletion (LD), Mean imputations (MEI), Mean above (MA), and Mean above below(MAB) and two steps nearest neighbour (2-NN).The comparison was performed using original data set, and missing values at 5%, 10%, 20%, 30% were simulated on Framingham risk scores under MCAR and MAR simulation on BMI values given some assumptions. Five performance indicators were used to describe the model minimum errors and goodness of fit for all the methods. The results showed that the 2-NN is the best replacement method at lower levels (5% and10%) of missing values while MA and MEI performed best at higher levels(15% and 20%) of missing values. All comparison was based on estimates closest to those of the original data where no value was missing. MAR results showed that 2-NN performed better than LD,MA,MAB, and MEI at 5%,10%, and 20% levels of missing data in terms of absolute difference in p-value to original data.
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Date Issued: 2019

Showing items 161 - 180 of 506

The characteristics and trends of rainfall on sub-Antarctic Marion Island and associated air circulation patterns

The effect of feeding varying inclusion levels of velvet bean (Mucuna pruriens) seed meal on growth performance and physicochemical attributes of broiler chicken

The effect of muscle type and freezing on the evolution of physico-chemical properties during processing of South African biltong and its final textural properties

The use of information and communication technologies in agricultural development in rural areas: case of smallholder farmers in Umzimvubu Local Municipality

Towards a reconstruction of Marion Island’s glacial history

Understanding the links between smallholder farmers and retailers of meat and vegetables in Mthatha, Mqanduli, Port St Johns and Tsolo, Eastern Cape, South Africa

Chemical evaluation, in vitro ruminal dry matter (DM) degradability and ruminal biological activity of common browse tree fruits of Alice

Integration of nanostructured metal sulfides into titanium (iv) oxide for high performance dye sensitized solar cell

Investigating communal farmer’s perceptions on production practices and evaluating pre-slaughter responsiveness of extensively reared Boran and Nguni steers

Cultivation, nutritional and pharmacological evaluation of Celosia argentea (L) Kuntze: an endangered wild vegetable in the Eastern Cape Province of South Africa

Studies on vine storage methods, planting techniques, paclobutrazol treatment, planting density and weevil management on sweetpotato (ipomoea batatas l.lam) cultivars promoted in South Africa

Surveillance study on pathogenic Acinetobacter species in freshwater environment of the Amathole and Chris Hani District Municipalities, Eastern Cape, South Africa

Profitability and technical efficiency of small-scale organic crop farmers’ in the Eastern Cape Province of South Africa

A comparative analysis of mobile application development frameworks: A case study of mobile application development for water usage management in Alice and Fort Beaufort communities

A Model for Intrusion Detection in IoT using Machine Learning

Aeolian processes and landforms at Mesrug on sub-Antarctic Marion Island

Amaranth (Amaranthus cruentus) growth and nutritional contents as affected by nitrogen and potassium fertiliser and plant density

An Assessment of the Environmental Impacts of Urban Sprawl in Buffalo City Metropolitan Municipality, Eastern Cape Province

Analyses of Retail and Transport Geography of Liquefied Petroleum Products in Ibadan metropolis, Nigeria

Application of some missing data techniques in estimating missing data in high blood pressure covariates