The Impact of Urban Sprawl on the Livelihood of Fringe Farmers in Mekelle, Ethiopia

The city of Mekelle is experiencing high population growth and haphazard settlement expansion resulting in urban sprawl[1]. City authorities have responded with periodic expropriation of adjacent rural land to extend the urban limits and, effectively, provide more land for development. Between 2005 and 2008, about 9883 farmer households were expropriated from their farms as a result of the rapid expansion of the city. Due to the poor administration of the acquisition and the follow-up utilization of the acquired land, displaced farmers are not only losing their livelihood but the compensation due is delayed and insufficient to prepare them for a decent shift in life. Again, the absence of a scientific method of valuation leads to dissatisfaction on the part of many affected farmers. This paper looks at the evolving picture of unfair displacement of families whose main source of livelihood is subsistence agriculture from their small land holdings resulting in complete deprivation and destitution. Material for putting together this paper came from an ongoing doctoral research study[2]. Primary data was obtained from a survey of 250 expropriated farmers. Findings show that the city is, indeed, sprawling into the nearby rural communities due to the uncontrolled and unauthorized acquisition and occupation of farmlands; a phenomenon that clearly has its roots in the poor land administration practices of Mekelle City Administration. The paper is structured into four parts: part one deals with the introduction covering the background, problem and objective; part two relates to review of literature and Ethiopian laws pertaining to the subject; part three covers the methodology adopted in writing the paper; part four delves into the findings; and part five is conclusion. Keywords: sprawl, expropriation, compensation, livelihood [1] Refers to unplanned and often inefficient use of urban land [2] ‘Urban Sprawl in Mekelle (Ethiopia): Causes, Consequences and Management Strategies.’ By the same author

New Coding/Decoding Techniques for Wireless Communication Systems

Wireless communication encompasses cellular telephony systems (mobile communication), wireless sensor networks, satellite communication systems and many other applications. Studies relevant to wireless communication deal with maintaining reliable and efficient exchange of information between the transmitter and receiver over a wireless channel. The most practical approach to facilitate reliable communication is using channel coding. In this dissertation we propose novel coding and decoding approaches for practical wireless systems. These approaches include variable-rate convolutional encoder, modified turbo decoder for local content in Single-Frequency Networks, and blind encoder parameter estimation for turbo codes. On the other hand, energy efficiency is major performance issue in wireless sensor networks. In this dissertation, we propose a novel hexagonal-tessellation based clustering and cluster-head selection scheme to maximize the lifetime of a wireless sensor network. For each proposed approach, the system performance evaluation is also provided. In this dissertation the reliability performance is expressed in terms of bit-error-rate (BER), and the energy efficiency is expressed in terms of network lifetime

Totarol as privileged natural product scaffold for antimalarial drug discovery

Malaria is one of the major killer diseases in many countries of southern Asia, South America and Africa. Today over 40% of the world population is at risk from malaria. It is the cause of 300 - 500 million infections and the death of more than 2 million people each year, most of whom are African children. Chloroquine has been the mainstream of malaria chemotherapy for nearly 60 years, but widespread resistance now limits its usefulness. A continuous effort to find alternative antimalarials to this drug has led to the discovery of other effective antimalarials of different types, such as aminoquinolines, artemisinins and nucleic acid inhibitors. However, the emergence of multi-drug resistant strains of the malaria parasite has caused a marked increase in malaria related deaths, and there is a continuous need to develop other new antimalarials. Natural products play an important role in the antimalarial drug discovery process. Quinine and derivatives of artemisinin, the two most important drugs available to treat sever falciparwn malaria, owe their origin to plants. Furthermore, several effective antimalarials have been synthesized using quinine as a model compound (e.g., aminoquinoline antimalarials) or are results of relatively simple chemical modifications on the parent natural products (e.g., artemisinin). In this thesis, the natural product scaffold “totarol", which possesses inherent antiplasmodial activity, was used to design and investigate the antiplasmodial activity of three different compound classes namely: Mannich bases, aminoalcohols and semicarbason derivatives. The aim was to incorporate important drug fragments into a natural product scaffold with intrinsic antiplasmodial activity, possibly leading to the discovery of new totarol based antimalarials. In the first class of compounds, a series of novel Mannich base derivatives of totarol have been designed and synthesized to mimic the known Mannich base antimalarials, such as amodiaquine, amopyroquine and other functionally related antimalarials. These compounds differed from each other in the nature of their amino methyl side chain which was varied to include different structural requirements. It was found that the secondary amine Mannich bases possessed better antiplasmodial activity against chloroquine sensitive strains of the parasite than the tertiary amine Mannich bases. However, none of the synthesized compounds were found to be as active as the parent compound (totarol). Based on the preliminary biological evaluations of the synthesized Mannich base derivatives, only selected primary amine derived /f-amino alcohols were synthesized in the second class of antimalarials. However, none of the synthesized compounds were found to possess significant antiplasmodial activity. This was consistent with previous findings whereby the presence of protonatable nitrogen at the beta position could be a necessary structural feature for high antiplasmodial activity with totarol-dcrived amino alcohols. The semicarbazone derivative of totarol also did not show any antiplasmodial activity. Furthermore, none of the 2-isopropylphenol derived Mannich bases showed significant antiplasmodial activity, suggesting the impo1iance of the diterpenoid backbone of totaro, in its inherent antiplasmodial activity

Agricultural Extension Service and Input Application Intensity: Evidence from Ethiopia

This paper examines factors that influence agricultural input adoption in the northern part of Ethiopia. Using a 730 households survey data set, a Tobit model is estimated to explain the factors that influence farmers’ decision to adopt modern inputs or not. The factors found to significantly influence included: plot size, oxen ownership, gender, age and literacy status of the household head, adult labor force, total non-farm income, extension service and location variables. The results confirm the adoption theory

Environmental Impact and Sustainability of Aggregate Production in Ethiopia

The production of aggregate for the infrastructural development of the country has been increasing for the last three decades due to the high urbanization rates in the main cities of the country and the ever-growing demand for basic infrastructural facilities. The environmental impact of both fine and coarse aggregate production is now hard to ignore especially on the outskirts of the main cities. These impacts are clearly seen on the degradation of landscape and land stability, pollution of water resource, pollution of the atmosphere due to dust, and societal impacts. There are clear local and international laws that protect the environment from the negative impact of any project, whereas the observed fact from abandoned and functioning quarry sites shows these rules are not followed strictly

ENHANCEMENT OF SUPERCONDUCTIVITY IN LEAD (Pb) BY INTENSIFIED GRAVITATIONAL INTERACTION BETWEEN ELECTRON PAIRS

This work focuses on the theoretical investigation of the possible enhancement of superconductivity for the superconducting lead (Pb) by intensified gravitational interaction (IGI) between electron pairs. By applying the quantization theory of gravity (QTG), we obtained expressions for the enhanced superconducting transition temperature (), and superconducting energy gap (). By using the experimental, theoretical values and some plausible approximations of the parameters in the obtained expressions, the phase diagrams of superconducting energy gap versus temperature for lead at  and the enhanced superconducting energy gap versus temperature for lead at are plotted. By combining the two phase diagrams, we had shown the possible enhancement of the superconducting transition temperature from to and its superconducting energy gap fromto  for the superconducting lead

Coexistence of Superconductivity and Ferromagnetism in Superconducting ErRh4B4

This research work focuses on the theoretical investigation of the possible coexistence of superconductivity and ferromagnetism in ErRh4B4. By developing a model Hamiltonian for the given system and by using the double time temperature-dependent Green’s function formalism, we obtained expressions for superconducting transition temperature (TC,), magnetic ordering temperature (Tm), superconducting and magnetic ordering parameters (Δ) and (η) respectively. By using the experimental and theoretical values and by considering plausible approximations of the parameters in the obtained expressions, the phase diagrams of superconducting transition temperature versus magnetic ordering parameter and magnetic ordering temperature versus magnetic ordering parameter are plotted. Finally, by combining the two phase diagrams, we showed the possible coexistence of superconductivity and ferromagnetism in ErRh4B4.Keywords: Superconductivity, ferromagnetism, order parameter, conduction electrons, localized electrons, Green’s function