The Relationship Between Urbanization and Precipitation in Kisumu City: Co-Integration Analysis

The work done in this study thesis is by empirical analysis. If two series are integrated of the same order, then the two series are said to be co-integrated and this is shown in the two series where the population series being non stationary is made stationary by third differencing and the stationary rainfall series subjected to the same order of differencing to achieve the co-integration rule. The OLS method was used and then the model parameters tested for adequacy. A linear Error Correction Model was fitted and evidence that a short term relationship between the rainfall and population series is seen to exist. Also, a high threshold value is observed at the second lag. A high R squared value of 0.9881 is an indication that the model fits well to the data.  A small p-value also indicates that the model is highly significant. Hence, it is recommended that a close analysis of population growth rates be analyzed to aid in the prediction of the rainfall rates movements. Keywords: OLS, Co-integrated, differencing, Error Correction Model, p-value

Improvement in the protein quality of African sorghum foods through compositing with cowpea

Lysine deficiency is a major nutritional problem faced by poor people living in the arid and semi-arid tropics who depend on sorghum as their staple food. This is because of poor lysine content and digestibility of sorghum proteins, which aggravates when sorghum is cooked in food. To address this nutritional problem, compositing with locally available lysine-rich legumes has been proposed. Therefore, this study investigated the effects of compositing with the African grain legume, cowpea, on the protein and functional quality of important traditional African sorghum foods. Two sorghum cultivars, a red, tannin (NS 5511) and a white tan plant, non-tannin (Orbit) composited with cowpea at 70:30 ratio, were used to prepare three traditional sorghum foods, ugali (unfermented thick porridge), uji (fermented thin porridge) and injera (fermented flatbread). The protein quality of the traditional sorghum foods was determined by measuring their protein contents, lysine and reactive lysine contents, and in vitro protein digestibility. The functional properties of the foods were studied using instrumental texture analysis. Other sensory properties of ugali were determined using a trained sensory panel. Compositing with cowpea increased the protein contents of the foods by up to 35% and 57% for NS 5511 and Orbit foods, respectively. Lysine contents of the food proteins increased by 67% to 139%. Reactive lysine content increased by 10% to 75%. Protein digestibility of the foods increased by 13% to 62%. There was approximately three- and two-fold increase in protein digestibility corrected amino score (PDCAAS) of NS 5511 and Orbit foods, respectively, due to addition of cowpea. However, Orbit-plus-cowpea foods still had better protein quality than NS 5511-plus-cowpea foods, primarily because of the tannins in the latter which bind the proteins thereby lowering their digestibility. Compositing reduced paste peak viscosity (PV) and cool paste viscosity (CPV) of uji porridge by 6% to 23%, and 6% to 12%, respectively, probably as a result of decreasing porridge starch content. Principal component analysis (PCA) showed that compositing contributed 38% of the variation in 17 sensory attributes of ugali. Compositing imparted cowpea flavour to ugali. Most of the variation in sensory properties (59%) of ugali was due to the quality characteristics of the sorghum cultivars. Compositing increased the stiffness of NS 5511 injera by up to 25%, while it reduced the stiffness of Orbit injera by up to 12%. These differences in stiffness suggested a weakening effect of weaker H-bonding between tannins and other food polymers such as proteins instead of stronger covalent bonds like those involved in proteins-protein interactions. Compositing important traditional sorghum foods with cowpea has potential for helping to solve lysine deficiency faced by sorghum consumers in the semi-arid tropics. However, it introduces cowpea flavour which may need to be eliminated, in foods intended for consumers not accustomed to cowpea flavour. CopyrightDissertation (MSc)--University of Pretoria, 2009.Food Scienceunrestricte

Physico-chemical modification of kafirin microstructures for application as biomaterials

Microparticles produced from kafirin, the sorghum grain prolamin protein, by molecular selfassembly using coacervation with acetic acid solvent are vacuolated. They have shown considerable potential for encapsulation of antioxidants and for preparation of high quality free-standing bioplastic films. However, the functional quality of these kafirin microstructures needs to be improved to exploit their potential application, particularly as biomaterials. Wet heat, transglutaminase and glutaraldehyde treatments were used to modify the physical structure and chemical properties of the kafirin microstructures. Heat treatment (50–96°C) increased microparticle average size by up to four-fold to ≈20 μm, probably due to disulphide cross-linking of kafirin proteins. The vacuoles within these microparticles enlarged up to >10-fold, probably due to greater expansion of air within the microparticles with higher temperature, as the vacuoles are probably footprints of air bubbles. As with heat treatment, glutaraldehyde (10–30%) treatment resulted in oval microparticles, up to about four-fold larger than the control, probably due to covalent glutaraldehyde-polypeptide linkage. Transglutaminase (0.1–0.6%) treatment had only slight effect on the size and shape of microparticles, probably because kafirin has very low lysine content, inhibiting transglutaminase-catalysed cross-linking through ε-(-glutamyl)-lysine bonding. Surface morphology using atomic force microscopy indicated that the microparticles apparently comprised coalesced nanostructures. With heat and transglutaminase treatments, the microparticles seemed to be composed of round nanostructures that coalesced into random irregular shapes, indicative of non-linear protein aggregation. In contrast, with glutaraldehyde treatment, the nanostructures were spindle-shaped and had a unidirectional orientation, probably due to linear alignment of the nanostructures controlled by glutaraldehyde-polypeptide linkage. Thin (<50 μm) films prepared from kafirin microparticles and conventional cast kafirin films were compared in terms of their water stability and other related properties. Films cast from microparticles were more water-stable compared to conventional kafirin films, probably because the large vacuoles within the kafirin microparticles may have enhanced protein solubility in the casting solution, thereby improving the film matrix cohesion. The films prepared from microparticles treated with glutaraldehyde were more water-stable compared to the control, despite the loss of plasticizer, probably due to formation of the covalent glutaraldehyde-polypeptide linkages. The potential of modified kafirin microparticles to bind bone morphogenetic protein-2 (BMP- 2) was investigated. Compared to a collagen standard, the BMP-2 binding capacity of control, heat-treated, transglutaminase-treated and glutaraldehyde-treated kafirin microparticles were 7%, 18%, 34% and 22% higher, respectively, probably mainly due to the vacuoles within the microparticles creating greater binding surface area. The safety, biodegradability and effectiveness of kafirin microparticle film and kafirin microparticle film-BMP-2 system in inducing bone growth were determined by a subcutaneous bioassay using a rat model. Kafirin microparticle film and kafirin microparticle film-BMP-2 system was non-irritant to the animals, probably because kafirin is non-allergenic. The kafirin microparticle film implants showed signs of some degradation but a large proportion of these implants was still intact by Day 28 post implantation, probably because of the low susceptibility of kafirin to mammalian proteolytic enzymes. Kafirin microparticle film-BMP-2 system did not induce bone growth, probably mainly due to low BMP-2 dosage and short study duration. Modification of kafirin microparticles by wet heat or glutaraldehyde treatment both result in increased size of the microparticles with similar gross structure. However, it is apparent that with both treatments the proteins within the pre-formed kafirin microparticles undergo some form of further assisted-assembly through different mechanisms. It seems that heat-induced disulphide cross-linking reinforces a layer around the nanostructures, probably rich in γ- kafirin polypeptides, that stabilizes the structure of the nanostructures. In contrast, glutaraldehyde-treatment appears to destabilize this structure-stabilizing layer through formation of γ-kafirin polypeptide-glutaraldehyde covalent bonding. This probably offsets the balance of attractive and repulsive forces between the different kafirin subclasses within the nanostructures, thereby resulting in collapsed nanostructures and linear realignment. A deeper understanding of the mechanism of kafirin self-assembly will be important for further development of kafirin microstructures for different applications.Thesis (PhD)--University of Pretoria, 2012.Food Scienceunrestricte

Robust estimation of heritability and predictive accuracy in plant breeding: evaluation using simulation and empirical data

UID/MAT/00297/2019 UIDB/00297/2020 SFRH/BSAB/105935/2014 SFRH/BSAB/142919/2018 Project PT/A13/17-DE/57339863 Grant PI 377/18-1 Grant OG 83/1-1 & OG 83/1-2BACKGROUND: Genomic prediction (GP) is used in animal and plant breeding to help identify the best genotypes for selection. One of the most important measures of the effectiveness and reliability of GP in plant breeding is predictive accuracy. An accurate estimate of this measure is thus central to GP. Moreover, regression models are the models of choice for analyzing field trial data in plant breeding. However, models that use the classical likelihood typically perform poorly, often resulting in biased parameter estimates, when their underlying assumptions are violated. This typically happens when data are contaminated with outliers. These biases often translate into inaccurate estimates of heritability and predictive accuracy, compromising the performance of GP. Since phenotypic data are susceptible to contamination, improving the methods for estimating heritability and predictive accuracy can enhance the performance of GP. Robust statistical methods provide an intuitively appealing and a theoretically well justified framework for overcoming some of the drawbacks of classical regression, most notably the departure from the normality assumption. We compare the performance of robust and classical approaches to two recently published methods for estimating heritability and predictive accuracy of GP using simulation of several plausible scenarios of random and block data contamination with outliers and commercial maize and rye breeding datasets. RESULTS: The robust approach generally performed as good as or better than the classical approach in phenotypic data analysis and in estimating the predictive accuracy of heritability and genomic prediction under both the random and block contamination scenarios. Notably, it consistently outperformed the classical approach under the random contamination scenario. Analyses of the empirical maize and rye datasets further reinforce the stability and reliability of the robust approach in the presence of outliers or missing data. CONCLUSIONS: The proposed robust approach enhances the predictive accuracy of heritability and genomic prediction by minimizing the deleterious effects of outliers for a broad range of simulation scenarios and empirical breeding datasets. Accordingly, plant breeders should seriously consider regularly using the robust alongside the classical approach and increasing the number of replicates to three or more, to further enhance the accuracy of the robust approach.publishersversionpublishe

Machine Learning Algorithm to Detect Impersonation in an Essay-Based E-Exam

Essay-based E-exams require answers to be written out at some length in an E- learning platform The questions require a response with multiple paragraphs and should be logical and well-structured These type of examinations are increasingly becoming popular in academic institutions of higher learning based on the experience of COVID-19 pandemic Since the exam is mainly done virtually with reduced supervision the risk of impersonation and stolen content from other sources increases Due to this there is need to design cost effective and accurate techniques that are able to detect cheating in an essay based E- exa

The Effect of Performance Contract Implementation on Service Delivery in Provincial Administration

In order for the Provincial Administration department in Kenya to deliver its mandate, it needs efficient and proper service delivery. The implementation of performance contracting was aimed at addressing quality of service delivery. Despite these reforms, there remain some challenges in terms of quality of service delivery. The study sought to evaluate the effect of implementing performance contract on service delivery in provincial administration and also evaluate the effectiveness of Performance Contracting in improving efficiency in service. The study used descriptive survey research design. Primary data was collected from a sample size of 147 drawn from a target population of 490 consisting of 90 employees of Provincial Administration and 400 members of the public. Both stratified random sampling and purposive sampling were used for Provincial Administration staff and members of the public respectively to pick the respondents. The data was gathered by use of a questionnaire that had both open and closed ended questions. Descriptive statistics was used to analyze data in form of frequencies and percentages, and presented in tables. The study revealed that the implementation of Performance Contracting was effective in improving efficiency in service delivery by the department. Keywords: Performance contract, competent, effectiveness, quality service delivery

Bioprospecting Staphylococcus Phages with Therapeutic and Bio-Control Potential

Emergence of antibiotic-resistant bacteria is a serious threat to the public health. This is also true for Staphylococcus aureus and other staphylococci. Staphylococcus phages Stab20, Stab21, Stab22, and Stab23, were isolated in Albania. Based on genomic and phylogenetic analysis, they were classified to genus Kayvirus of the subfamily Twortvirinae. In this work, we describe the in-depth characterization of the phages that electron microscopy confirmed to be myoviruses. These phages showed tolerance to pH range of 5.4 to 9.4, to maximum UV radiation energy of 25 µJ/cm2, to temperatures up to 45 °C, and to ethanol concentrations up to 25%, and complete resistance to chloroform. The adsorption rate constants of the phages ranged between 1.0 × 10−9 mL/min and 4.7 × 10−9 mL/min, and the burst size was from 42 to 130 plaque-forming units. The phages Stab20, 21, 22, and 23, originally isolated using Staphylococcus xylosus as a host, demonstrated varied host ranges among different Staphylococcus strains suggesting that they could be included in cocktail formulations for therapeutic or bio-control purpose. Phage particle proteomes, consisting on average of ca 60–70 gene products, revealed, in addition to straight-forward structural proteins, also the presence of enzymes such DNA polymerase, helicases, recombinases, exonucleases, and RNA ligase polymer. They are likely to be injected into the bacteria along with the genomic DNA to take over the host metabolism as soon as possible after infection

Bioprospecting Staphylococcus Phages with Therapeutic and Bio-Control Potential

Emergence of antibiotic-resistant bacteria is a serious threat to the public health. This is also true for Staphylococcus aureus and other staphylococci. Staphylococcus phages Stab20, Stab21, Stab22, and Stab23, were isolated in Albania. Based on genomic and phylogenetic analysis, they were classified to genus Kayvirus of the subfamily Twortvirinae. In this work, we describe the in-depth characterization of the phages that electron microscopy confirmed to be myoviruses. These phages showed tolerance to pH range of 5.4 to 9.4, to maximum UV radiation energy of 25 µJ/cm2, to temperatures up to 45 °C, and to ethanol concentrations up to 25%, and complete resistance to chloroform. The adsorption rate constants of the phages ranged between 1.0 × 10−9 mL/min and 4.7 × 10−9 mL/min, and the burst size was from 42 to 130 plaque-forming units. The phages Stab20, 21, 22, and 23, originally isolated using Staphylococcus xylosus as a host, demonstrated varied host ranges among different Staphylococcus strains suggesting that they could be included in cocktail formulations for therapeutic or bio-control purpose. Phage particle proteomes, consisting on average of ca 60–70 gene products, revealed, in addition to straight-forward structural proteins, also the presence of enzymes such DNA polymerase, helicases, recombinases, exonucleases, and RNA ligase polymer. They are likely to be injected into the bacteria along with the genomic DNA to take over the host metabolism as soon as possible after infection

Dagaa Fishery: The Unknown Wealth of Lake Victoria

The paper discusses contribution of dagaa Rastreneobola argentae fishery to Tanzanian economy. It uses data from two studies conducted in Lake Victoria as well as literature retrieved from Fisheries Division and other institutions. Results indicate that dagaa fishery generates an average monthly income over $150 to individual fisher/trader, provided employment and brought in substantial foreign exchange over$2 million annually. This has enabled government to improve road networks, health care and education systems within the dependent communities. However, the fishery is still faced with inadequate technologies for processing and value addition, poor local markets for fish and little exploitation among others. In conclusion, dagaa is an important resource among the fisheries of Lake Victoria. Improved handling and processing and promotion of economic value are likely to increase benefits to the riparian communities as well as sustaining already depleted Nile perch stock

\u27It is a disease which comes and kills directly\u27: What refugees know about COVID-19 and key influences of compliance with preventive measures

Background: Refugees are at increased risk for COVID-19 infection in part due to their living conditions, which make it harder to adopt and adhere to widely accepted preventive measures. Little empirical evidence exists about what refugees know about COVID-19 and what they do to prevent infection. This study explored what refugee women and their health care workers understand about COVID-19 prevention, the extent of their compliance to public health recommendations, and what influences the adoption of these measures. Methods: In October 2020, we conducted 25 in-depth interviews with facility and community health care staff (n = 10) and refugee women attending antenatal and postnatal care services (n = 15) in Eastleigh, Nairobi. Findings: While researchers found a high level of awareness about COVID-19 and related prevention and control measures among refugee women, various barriers affected compliance with such measures, due in part to poverty and in part to rampant misconceptions informed by religious beliefs and political narratives about the virus. Conclusions: These findings indicated that Kenya\u27s Ministry of Health needs to institute a concerted and continuous education program to bring refugee communities up to speed about COVID-19 and its prevention. In addition to disseminating information about the need to wear masks and repeatedly wash hands, supplies-masks, soap and access to water-need to be made available to poor refugee communities. Future research could explore which measures for disseminating factual information work best in refugee populations with different cultural norms and how best to target interventions to these groups