Breeding Sorghum [Sorghum bicolor (L.) Moench] for drought tolerance and medium-maturity.

Doctor of Philosophy in Plant Breeding. University of KwaZulu-Natal, Pietermaritzburg, 2017.Abstract available in PDF file

Assessment of Magnitude and Associated Factors of Emergence Delirium in the Post Anesthesia Care Unit at Tikur Anbesa Specialized Hospital, Ethiopia

BACKGROUND: Emergence delirium (ED) is known as an acute agitation and confusion occurring during or immediately following emergence from general anesthesia, in the Operation Room or post anesthesia care unit (PACU). ED results in significant morbidity and complications resulting in longer hospital stays. We studied the magnitude and risk factors of ED in the general surgical population.METHODS: An institution-based prospective cross-sectional study was conducted on patients who underwent surgical procedure at Tikur Anbessa Specialized Hospital, Ethiopia, from March 6 - May 1, 2017. Data was collected using patient interview and chart review. Patients with Richmond Agitation Sedation Scale ≥+1 at any time were considered to have emergence delirium/agitation. Categorical data was analyzed using the fishers exact test . Continuous data was analyzed using student t-test. Independent variables were analyzed using binary logistic regression. P-value of <0.05 was considered as cutoff point to test for statistically significance.RESULT: The overall magnitude of Emergence Delirium in this study was 31.7%. Older age (CI=4.266 – 12.095, P=0.001), substance abuse (OR =4.6, CI=1.962 – 10.863, P=0.001), preoperative anxiety (OR= 2.4, CI=1.140 – 5.244, P=0.02), benzodiazepine premedication (OR= 8, CI=2.788 – 23.21,P=0.001), excessive blood loss (OR=3.38, CI=1.789 – 6.412, P=0.001), postoperative pain (OR=3.37, CI=2.015 – 6.934, P=0.001) and longer PACU stay (CI=18.645 – 26.766, P=0.001) were positively associated with Emergence Delirium.CONCLUSION: The magnitude of emergence delirium is high and it is associated with older age, substance abuse, premedication with benzodiazepine, excessive blood loss postoperative pain and longer PACU stay.

The development of novel passive and active photonic-crystal devices

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 158-169).Photonic crystals are anticipated to have impact on large-scale photonic integrated circuits by allowing the creation of compact and efficient devices such as waveguides, splitters, microcavity filters, light emitting diodes, and lasers. Previous experimental research has mainly focused on photonic crystals composed of a lattice of air holes etched into dielectric slabs. This thesis discusses the design, fabrication, and characterization of the "inverse" structure, a square lattice of dielectric-rods in air. Bandgap guiding of 1.5 lam light is experimentally demonstrated for a photonic-crystal waveguide created by introducing a line-defect of smaller-radii rods. To provide efficient optical coupling between input/output dielectric waveguides and the photonic-crystal waveguide, an adiabatic taper having two stages is employed. Furthermore, the thesis investigates novel photonic-crystal devices and fabrication schemes. An expose-develop-etch (EDE) method is utilized to fabricate rod-based photonic-crystal devices in III-V and SOI material systems. The thesis also presents an electrically-activated linear-waveguide photonic-crystal laser. A compact microcavity is created by introducing a defect inside a one-dimensional photonic crystal. Electrical-activation and edge-emission are achieved by patterning microcavity waveguides into p-i-n-doped epitaxial heterostructures. The compact photonic-crystal laser is anticipated to have impact on the integration of optical devices on the same chip.Solomon Assefa.Ph.D

Design and fabrication of sharp bend photonic crystal slab waveguides

Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; and, (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2001.Includes bibliographical references (leaves 70-71).A periodic arrangement of atoms in a crystal presents a periodic potential for electrons. The bragg diffraction of electrons from the atoms may lead to a band gap, which represents a range of frequencies the electrons cannot have in the crystal. An analogous effect takes place in photonic crystals, which are periodic arrangement of layers of dielectric media. Scattering at the interface of the different layers produces a band gap for photons. The current effort to make integrated optical chips requires guiding light around sharp corners with a radius of curvature on the order of a wavelength. Photonic crystals serve this purpose by providing efficient sharp bend waveguides. An array of defects in a photonic crystal localizes modes in the band gap. This effect is used to build linear and 900 bend waveguides.by Solomon Assefa.S.B.M.Eng.and S.B

Exploring the implementation of the ‘model families’ approach as a strategy for diffusing desirable health practices in the community: the case of Yelmana-Denssa district, Ethiopia

Magister Public Health - MPHEthiopia‟s health extension programme (HEP), which aims to improve access to and extend the coverage of health services in the country, makes use of the „model families‟ approach as a strategy for diffusing desirable health practices in the community. The approach, which emphasises prevention and health promotion, assumes that through training and accreditation „model families‟ will be able to set an example and encourage communities to embrace healthy lifestyles. However, the programme‟s implementation is not progressing at the pace originally envisaged. In addition, factors influencing the implementation of the „model families‟ approach have not, to date, been explored adequately. Thus, the aim of this study is to investigate the factors hindering or enabling the implementation of the „model families‟ approach as a strategy for improving primary health care (PHC) services in Yelmana-Denssa District (YDD)

Factors Influencing Knowledge Transfer in Onshore Information Systems Outsourcing in Ethiopia

Knowledge transfer in onshore information systems (IS) outsourcing projects in Africa is an important but under-researched phenomenon. This study focuses on the client-vendor perspective and examines the factors that influence knowledge transfer in onshore information systems outsourcing in Ethiopia. Conceptually, knowledge-based perspectives of IS outsourcing is used to identify an initial set of factors to frame the empirical study. This is followed by semi-structured interviews with ten project managers. The findings indicate that five key factors, namely mutual absorptive capacity, mutual learning intent, mutual trust, mutual disseminative capacity and project staff turnover influence knowledge transfer in outsourced IS projects. The results suggest that development and management of the resources, processes and behaviors implied by these factors are vital to ensure successful inter-organizational knowledge transfer and to reverse or minimize the failure rates of outsourced IS projects. The study concludes with implications for research and practice

Prevalence and Associated Factors of Thyroid Incidentaloma among Adult People Attending Gondar University Hospital, Northwest Ethiopia Temesgen Tadesse1

BACKGROUND: Incidentally discovered thyroid lesions have become highly common in the development and more frequent utilization of highly sensitive imaging modalities, like ultrasound. However, little is known about its prevalence and associated factors in Ethiopia. The aim of this study was to determine the prevalence of thyroid incidentalomas and associated factors through ultrasound (US) among adults attending Gondar University Hospital.METHODS: A hospital-based cross-sectional study was carried out on 290 adults aged 15 years and above. Out of the adults who visited the hospital during the study, those who neither had history of thyroid disease, thyroid surgery, nor clinically palpable thyroid nodules were involved in the investigation. The participants were examined using a high frequency linear-array transducer (7MHz). For comparing men and women, the unpaired t-test wasused. Binary logistic analysis was used to identify the associated factors, and a P-value < 0.05 was considered statistically significant.RESULT: The frequency of thyroid incidentaloma was found to be 33.4% (95% CI: 27.9, 38.9). Thyroid incidentaloma was detected in 42.4% of the females and 22.7% of the males (P<0.001). About 63% had single and 37% multiple thyroid nodules. About 25.8% had thyroid nodules greater than 1cm. In the multivariable logistic regression analysis, increasing age (AOR=5.96; 2.34, 15.15) and female sex (AOR=3.01; 1.73, 5.26) were significantly associated with thyroid incidentalomas.CONCLUSION: The frequency of thyroid incidentaloma (TI) was found to be high in this study and much higher among older women. Solitary and small sized thyroid nodules were commonly seen in the study.

Flow Regime Classification and Hydrological Characterization: A Case Study of Ethiopian Rivers

The spatiotemporal variability of a stream flow due to the complex interaction of catchment attributes and rainfall induce complexity in hydrology. Researchers have been trying to address this complexity with a number of approaches; river flow regime is one of them. The flow regime can be quantified by means of hydrological indices characterizing five components: magnitude, frequency, duration, timing, and rate of change of flow. Similarly, this study aimed to understand the flow variability of Ethiopian Rivers using the observed daily flow data from 208 gauging stations in the country. With this process, the Hierarchical Ward Clustering method was implemented to group the streams into three flow regimes (1) ephemeral, (2) intermittent, and (3) perennial. Principal component analysis (PCA) is also applied as the second multivariate analysis tool to identify dominant hydrological indices that cause the variability in the streams. The mean flow per unit catchment area (QmAR) and Base flow index (BFI) show an incremental trend with ephemeral, intermittent and perennial streams. Whereas the number of mean zero flow days ratio (ZFI) and coefficient of variation (CV) show a decreasing trend with ephemeral to perennial flow regimes. Finally, the streams in the three flow regimes were characterized with the mean and standard deviation of the hydrological variables and the shape, slope, and scale of the flow duration curve. Results of this study are the basis for further understanding of the ecohydrological processes of the river basins in Ethiopia

Impact of Technology Adoption through Dissemination Innovation Platforms (IP) on Yield, Food Security and Poverty: Evidence from Major Wheat Producing Regions of Ethiopia

Despite the high wheat production potential of Ethiopia, domestic production has been unable to match domestic demand, forcing the country to be a net wheat importer. Several development activities have aimed at increasing improved technological adoption to boost wheat yield. These have used linear and top-down approaches to disseminate different technologies. Recently, a new approach known as a technology dissemination innovation platform (IP) has been tried in four of the major wheat producing regions by the Support to Agricultural Research for Development of Strategic Crops (SARD-SC) wheat project. Despite this, there has no empirical investigation of this approach. This paper details the result of investigating the impact of wheat technology adoption through a technology dissemination IP approach. It uses two period survey data collected from 506 sample households in 2012 and 2016. Household Food Insecurity Access Scale (HFIAS) measures were used to investigate the impact of the intervention on food security and a simple poverty scorecard approach to assess the impact on poverty. Both propensity score matching and difference-in-difference econometric models were utilized to investigate the impact on wheat yields. The results reveal that the intervention brought about a significant and positive impact on food security, poverty and wheat yield. Adapting an innovation platform approach would, therefore, have a positive impact on yield increment, food security and poverty in implementing projects that have national importance. In addition, it is clear the current widely used, linear, top-down extension approach should be replaced by an approach that follows a technology innovation platform and which would provide a positive impact in these areas

Effects of Sowing Methods, Seed Rates and Sowing Depths on Growth Performance and Grain Yield of Tef [Eragrostis tef (Zucc.) Trotter]

Three field experiments were carried out on black soil (Vertisols) at Debre Zeit Agricultural Research Center during the main season between 2011 and  2013 to determine appropriate sowing/planting methods, seed rates, inter- and intra-row spacings, and planting depth for tef. Each experiment was laid  out in a randomized complete block design with three replications. Data were taken on days to panicle emergence and to maturity, plant height, panicle  length, lodging index, shoot biomass, and grain yield. Combined analyses of variance over years showed that sowing methods had no significant effect  on any of the traits assessed, while sowing methods and seed rates interaction effects were significant for all the traits evaluated. Irrespective of sowing  methods significantly higher grain yields were recorded with higher seeding rates (10-25 kg/ha). Among the spacing treatments, sowing with 10 cm row  spacing showed the highest mean grain (2621 kg/ha) and shoot biomass (21861 kg/ha) yield. Hill planting irrespective of the row spacing gave the lowest  grain and shoot biomass yield, while transplanting, gave intermediate grain and shoot biomass yield comparable to those of row sowing. In the third  experiment that combined row spacing and sowing depth, the highest grain yield (2404 kg/ha) was obtained from 20 cm row spacing by 3 cm planting  depth followed by 20 cm row spacing by 5 cm planting depth (2292 kg/ha). Overall, based on the results of this study, seed rates of 10-15 kg/ha for both  broadcasting and row spacing, and row spacing of 20 cm and sowing depth of 3 cm would be recommended for tef production on black soils at Debre  Zeit and other similar areas. &nbsp