Dual-layer frequency-selective grid polarizers on thin-film substrates for THz applications

Dual-layer frequency-selective subwavelength grid polarizers on thin-film dielectric substrates are proposed for THz and sub-THz applications. The dual-layer grids possess enhanced (squared) polarizing efficiency at a sequence of discrete frequencies in reflection and within extended frequency bands in transmission as compared to conventional single grids.

The protection and security of vulnerable populations in complex emergencies using the Dadaab refugee camps in the north eastern province of Kenya as a case study

The past two decades has seen a dramatic upheaval in the international world order: the end of the Cold War, the 9/11 attacks and the subsequent 'War on Terror', increased Jihadist activities, the accelerated pace of globalization, climate change and the 2008 global financial crisis have contributed to fear, uncertainty, poverty, conflict, massive displacements of populations of asylum seekers and refugees globally and a proliferation of Protracted Refugee Situations (PRS), defined as situations in which refugees have been in exile 'for 5 years or more after their initial displacement, without immediate prospects for implementation of durable solutions. In the past two decades there has been a huge proliferation of these with more than 7.2 million refugees now trapped in these PRS, with a further 16 million internally displaced persons (IDPs) trapped in camps within their own countries. The Dadaab refugee complex in Kenya, which of as March 2012, holds over 463,000 refugees, is the most significant and extreme example in recent times of a PRS. It was established in 1991 following the collapse of the Somali Government of Dictator Siad Barre, and the disintegration of Somalia into the chaos that still exists today. PRS such as Dadaab raise particular issues about humanitarianism in terms of aid, protection, security, human rights and the actions (or inaction) of the various stakeholders on an international, national and local level. This thesis investigates these issues by the use of a case study methodology on Dadaab as a PRS, framed in the context of humanitarianism and in particular the issues that arise in terms of how the international community, the UN system and individual states provide assistance and protection to vulnerable populations. Although the refugee camps have been in existence (as of 2012) for over 20 years, there has never been such a detailed study of Dadaab (or any other PRS) undertaken to date and would be of interest to academics in the areas of international relations, refugee/migration studies and global Governance as well as practitioners in both humanitarian response and development

Investigations into selective metabolic aspects of bifidobacteria: carbohydrate metabolism, fatty acid biosynthesis and plasmid biology

The gastrointestinal tract (GIT) is a diverse ecosystem, and is colonised by a diverse array of bacteria, of which bifidobacteria are a significant component. Bifidobacteria are Gram-positive, saccharolytic, non-motile, non-sporulating, anaerobic, Y-shaped bacteria, which possess a high GC genome content. Certain bifidobacteria possess the ability to produce conjugated linoleic acid (CLA) from linoleic acid (LA) by a biochemical pathway that is hypothesised to be achieved via a linoleic isomerase. In Chapter two of this thesis it was found that the MCRA-specifying gene is not involved in CLA production in B. breve NCFB 2258, and that this gene specifies an oleate hydratase involved in the conversion of oleic acid into 10-hydroxystearic acid. Prebiotics are defined as non-digestible food ingredients that beneficially affect the host by selectively stimulating growth and/or activity of one or a limited number of bacteria in the colon. Key to the development of such novel prebiotics is to understand which carbohydrates support growth of bifidobacteria and how such carbohydrates are metabolised. In Chapter 3 of this thesis we describe the identification and characterisation of two neighbouring gene clusters involved in the metabolism of raffinose-containing carbohydrates (plus related carbohydrate melibiose) and melezitose by Bifidobacterium breve UCC2003. The fourth chapter of this thesis describes the analysis of transcriptional regulation of the raf and mel clusters. In the final experimental chapter two putative rep genes, designated repA7017 and repB7017, are identified on the megaplasmid pBb7017 of B. breve JCM 7017, the first bifidobacterial megaplasmid to be reported. One of these, repA7017, was subjected to an in-depth characterisation. The work described in this thesis has resulted in an improved understanding of bifidobacterial fatty acid and carbohydrate metabolism, Furthermore, attempts were made to develop novel genetic tools.

The impact of saving and credit cooperatives on food security in the West Amhara Region of Ethiopia

In rural Ethiopia, among other things, lack of adequate financial service is considered as the basic problem to alleviate rural poverty and to solve the problem of food insecurity. Commercial banks are restricted to urban centres. Providing rural financial service through RUSACCO to the poor has been proposed as a tool for economic development and for achieving food security. Evidence from research in this regard has been so far scanty, especially in rural Ethiopia. The aims of this study are to analyze the determinants of membership, to identify socioeconomic and demographic factors that influence members’ participation in RUSACCOs and to quantify the impact of RUSACCOs on member households’ food security. The study was conducted in two purposely selected woredas in the Amhara region one from food insecure (Lay Gayint woreda) and the other from food secure (Dejen woreda). Six RUSACCOs were selected randomly from these two woredas. Both qualitative and quantitative data were collected. Key informant interviews, focus group discussions and survey techniques were used to collect primary data. Collected data was then analyzed using mixed methods depending on the nature of data. For quantitative data analysis appropriate statistical models were used. The study result reveals that the number of members in each RUSACCO is very small. However, the majority of non-member respondents are willing to join RUSACCO. Lack of information about the benefits of RUSACCO membership is the main problem why many rural poor do not join RUSACCOs. Members participate in different aspects of the cooperatives, starting from attending general assembly up to board membership. They also participate actively in saving and borrowing activities of RUSACCO. The majority of the respondents believe the RUSACCO is a vital instrument in combating food insecurity. The empirical findings indicate that gender, marital status, occupation, educational level, participation in local leadership and participation in other income generation means determine the decision of rural poor to join a RUSACCO or not. The amount of saving is determined by household head occupation, farming experience and income level. While age of household head, primary occupation, farming experience, date of membership, annual total consumption expenditure, amount of saving and participation in other income generation activities influence members’ amount of borrowing by RUSACCO members. Finally, the study confirms that RUSACCO participation improves household food security. RUSACCO membership has made positive impact on household total consumption expenditure and food expenditure.