Mj Davies

Women, marketplaces and exchange partners amongst the Marakwet of northwest Kenya

Based on recent fieldwork, this paper examines the intersecting economic activities of Marakwet women in northwest Kenya with a particular focus on exchange friendships. We highlight the need to expand previous definitions of tilia, based on male exchange of livestock, to include a variety of exchange friendships including those between women. Through investigating womens economic activities in local marketplaces, we demonstrate that marketplaces facilitate the formation of tilia partnerships between women from different areas, and shape womens kinship and friendship interactions within the context of their market activities. We argue that there is a synergy between womens market activities and exchange relationships, but we also emphasise that market activities and tilia exchange relationships are part of the matrix of household economic decision-making navigated by Marakwet women. This has important implications for how we view and support the social and economic contributions of womens activities. Womens tilia relations provide a number of benefits to their trading activities, households and communities, and as such we suggest that rural development interventions would do well to consider and build upon these networks of exchange relations.

Electromagnetic stirring in a microbioreactor with non-conventional chamber morphology and implementation of multiplexed mixing

Abstract BACKGROUND Microbioreactors have emerged as novel tools for early bioprocess development. Mixing lies at the heart of bioreactor operation (at all scales). The successful implementation of micro‐stirring methods is thus central to the further advancement of microbioreactor technology. The aim of this study was to develop a micro‐stirring method that aids robust microbioreactor operation and facilitates cost‐effective parallelization. RESULTS A microbioreactor was developed with a novel micro‐stirring method involving the movement of a magnetic bead by sequenced activation of a ring of electromagnets. The micro‐stirring method offers flexibility in chamber designs, and mixing is demonstrated in cylindrical, diamond and triangular shaped reactor chambers. Mixing was analyzed for different electromagnet on/off sequences; mixing times of 4.5 s, 2.9 s, and 2.5 s were achieved for cylindrical, diamond and triangular shaped chambers, respectively. Ease of micro‐bubble free priming, a typical challenge of cylindrical shaped microbioreactor chambers, was obtained with a diamond‐shaped chamber. Consistent mixing behavior was observed between the constituent reactors in a duplex system. CONCLUSION A novel stirring method using electromagnetic actuation offering rapid mixing and easy integration with microbioreactors was characterized. The design flexibility gained enables fabrication of chambers suitable for microfluidic operation, and a duplex demonstrator highlights potential for cost‐effective parallelization. Combined with a previously published cassette‐like fabrication of microbioreactors, these advances will facilitate the development of robust and parallelized microbioreactors.

Chapter 2:Microfluidics Theory in Practice

Analytical detection methods based on lab-on-a-chip (LoC) technologies have been on the rise in the last decade as they provide numerous advantages in comparison with their larger-scale counterparts, like low sample volume requirements, high-throughput capability and better performance. LoC systems designs and development are simultaneously dependent upon the physicochemical properties of the analyte under consideration and governed by the fundamental laws of fluid dynamics, that are usually applied at the macroscale. This chapter provides a brief overview of fluid hydrodynamics and also transport phenomena at the microscale that are relevant to analyte-detection science. This chapter will provide a solid grounding in the possibilities and limitations inherent to operating at the small scale.