Reconciling Mass Functions with the Star-Forming Main Sequence Via Mergers

We combine star formation along the `main sequence', quiescence, and clustering and merging to produce an empirical model for the evolution of individual galaxies. Main sequence star formation alone would significantly steepen the stellar mass function towards low redshift, in sharp conflict with observation. However, a combination of star formation and merging produces a consistent result for correct choice of the merger rate function. As a result, we are motivated to propose a model in which hierarchical merging is disconnected from environmentally-independent star formation. This model can be tested via correlation functions and would produce new constraints on clustering and merging.Comment: MNRAS, in pres

A Diplomat\u27s Portrait: The United States Department of State\u27s View on French Imperial Policy Regarding Syrian Religious Minorities of 1918-1922

This thesis examines documents from the US department of State relating to the Internal Affairs of Turkey in the years of 1918-1922, to answer questions pertaining to French imperial policy directed toward minority groups in French Mandate Syria, which included present-day nations of Lebanon and Syria. Of the many minority groups present in French Mandate Syria, I chose to examine the Maronite, Druze, Alawi, Eastern Christian, and Armenian communities because of their significant role in the state-building of Syria and Lebanon. By using documents originating from US diplomats, this thesis attempts to present the United States’ view on these imperial policies. In the formation of this perspective, the thesis asks some of the following questions: What were the effects of French imperial policies on Syrian minorities? And how did French imperial policy regarding minorities shape French Syrian society as a whole? To answer these questions as completely as possible, I supplemented the archival sources with material from significant scholars in Levantine and broader Mid-East history, like Albert Hourani and Yaron Friedman. My research suggests that policies pursued had a negative impact on all of the minorities but to a lesser extent for the Maronites, and other Christians. It also suggests that French imperial policy led to the creation of a violent society but steps could have been taken to produce a more peaceful outcome. The final goal of this thesis is to provide the historical narratives of the minority groups with an additional perspective, that of the US diplomats throughout the region

The Physiological Response of sub-Arctic Lichens to Their Abiotic Environment

The effect of environmental factors on metabolic processes of sample thalli, of four sub-Arctic lichen species from Abisko, Sweden (68.37˚N, 18.69˚E). Nephroma arcticum, Cladina mitis, C. stellaris and C. rangiferina, which are found in contrasting niche habitats within the same ecosystem, have been studied. An oxygen electrode apparatus has been used to study the effects of air temperature, thallus irradiance intensity and climatic regime during thallus storage, on the rate of net photosynthesis and dark respiration of sample thalli, in a series of studies on the four lichen species named above. Environmental temperature and light intensity both significantly affected the rate of thallus net photosynthesis (NP) in samples of all four species. The mean rate of thallus NP was significantly depressed at 17⁰C in all four species due to an exponential increase in respiratory rate with rising temperature. Maximal NP was achieved at 5⁰C in N. arcticum, 10⁰C in C. rangiferina, and NP at 5 & 10⁰C were not significantly different in C. mitis and C. stellaris. Optimum light intensity for photosynthesis was 340 µmol m-2 s-1 in all four species; however, temperature significantly increased the light compensation point of photosynthesis. Furthermore, mean light compensation points were greater in the more shaded adapted species N. arcticum and C. mitis; suggesting, as found in vascular plants, lichens exhibit photosynthetic characteristics adapted to their abiotic environment. C. mitis thalli did not provide any evidence of plastic adaptation to temperature over a six day storage period; whereas, N. arcticum samples exhibited increased NP after six days at 10 & 15⁰C compared to non-acclimatized samples. Prolonged storage at 10⁰C appeared to be detrimental to samples of C. stellaris. Responses to temperature and light intensity were similar to those found, in similar species, in photosynthetic rate investigations utilizing IRGA apparatus; validating the use of O2 electrode experiments using small samples of thallus tissue, as used in this investigation. The response of species, within this study, to environmental factors was slightly different to those obtained in similar studies for North American populations, which suggests that lichens may exhibit some within-species genetic variation between lichen populations from different continents. Analysis of moisture availability, from past climate-data of the region from which the lichen populations are found, suggests that the growth season of sub-Arctic lichens is very different to that of vascular plants that are within the same ecosystem. Future warming may cause longer, wetter Arctic Autumns and Springs, which would benefit lichen biomass, but environmental warming would suppress lichen growth and promote vascular plant productivity.\u

Sub-Unit Vaccines for <i>Brucella</i>

Brucella species are the causative agents of brucellosis, which is regarded as the world's most prevalent zoonotic disease. Brucellosis is endemic to the Middle East, Mexico, Asia, South America and the Mediterranean and causes significant economic losses in livestock in these areas of the world, as well as being a reservoir for human brucellosis. Although there are live attenuated vaccines available for brucellosis, they have many drawbacks when used in animals, and are still infectious to humans. It is clear from this that there is a need for a new effective vaccine for brucellosis for both animal and human use. There are increasing instances of ATP-binding cassette (ABC) systems being identified as virulence factors or potential vaccine candidates. In this study inventories of all the ABC systems encoded by five sequenced Brucella strains were compiled. These inventories were compared and differences have been found that could aid in the identification of virulence factors of Brucella. This study also explores the potential of ATP-binding cassette transporters as sub-unit vaccines against Brucella melitensis 16M. Eight ABC transporter proteins (PotD, PotF, Cgt, CydD, LolE, FbpA, OppA and ZnuA) have been produced using recombinant protein technologies, and their protective efficacy was evaluated in a number of studies using the murine model of B. melitensis infection. Of the eight vaccine candidates selected two have shown potential as novel vaccines against brucellosis. PotD and PotF are putative polyamine binding proteins of Brucella and show protection against experimental challenge of approximately 1x104 CFU of B. melitensis 16M when expressed by DNA vaccines or used in a PotD/PotF combination vaccine. Through this work a duel adjuvant system (ISCOMs and CpG) has been identified as a more effective adjuvant for Brucella vaccines than others previously used

A Homegrown DSMC-PIC Model for Electric Propulsion

Powering spacecraft with electric propulsion is becoming more common, especially in CubeSat-class satellites. On account of the risk of spacecraft interactions, it is important to have robust analysis and modeling tools of electric propulsion engines, particularly of the plasma plume. The Navier-Stokes equations used in classic continuum computational fluid dynamics do not apply to the rarefied plasma, and therefore another method must be used to model the flow. A good solution is to use the DSMC method, which uses a combination of particle modeling and statistical methods for modeling the simulated molecules. A DSMC simulation known as SINATRA has been developed with the goal to model electric propulsion plumes. SINATRA uses an octree mesh, is written in C++, and is designed to be expanded by further research. SINATRA has been initially validated through several tests and comparisons to theoretical data and other DSMC models. This thesis examines expanding the functionality of SINATRA to simulate charged particles and make SINATRA a DSMC-PIC hybrid. The electric potential is calculated through a 7-point 3D stencil on the mesh nodes and solved with a Gauss-Seidel solver. It is validated through test cases of charged particles to demonstrate the accuracy and capabilities of the model. An ambipolar diffusion test case is compared to a neutral diffusion case and the electric field is shown to stabilize the diffusion rate. A steady state flow test case shows the simulation is able to stabilize and solve the electric potential for a plume-like scenario. It includes additional features to simplify further research including a comprehensive user manual, industry-standard version control, text file inputs, GUI control, and simple parallelism of the simulation. Compilation and execution are standardized to be simple and platform independent to allow longevity of the code base. Finally, the execution bottlenecks of linking particles to cells and particle moving were removed to reduce the simulation time by 95%

Plastic Waste Makers Index: Basis of Preparation

The Plastic Waste Makers Index report comprises of three components, namely a Steering Committee of seven experts reflecting knowledge and experience of: 1. Material flow analysis 2. Financing and ownership analysis 3. Circularity assessment This document outlines the steps taken to complete each analysis. It can be read independently of the Method in Detail section in the Plastic Waste Makers Index Report

Farmers’ Agency and Experiences of Agricultural Change in Rural Kenya: Insights from Exploratory Fieldwork

Using novel agricultural technologies to boost farm productivity in the face of climatic and demographic disruption remains a priority for African policy and research. This paper uses an innovative, participatory and ethnographic methodology to explore, through farmers’ experiences, the historical pathways of social, ecological and technical (socio-eco-technical) change that have reshaped agriculture, livelihoods and rural landscapes in three sites in Kenya (Machakos, Siaya and Kisumu Counties) over recent decades. The paper identifies events and processes that triggered major changes in farming systems at household and community levels. Insights from engagements with farmers reflect an evolution in the strategic direction of agricultural development in Kenya from a more ‘bureaucratic’ mode during the colonial and immediate post-independence periods to a more ‘technocratic’ mode today. In the bureaucratic mode, the state was at the centre and aspired to align all farming practices and technologies with the priorities and programmes determined by the national government. In the contemporary period of technocratic development, agricultural programmes and interventions have been designed by scientific experts and implemented by technical agencies through the institutional form of short-term projects and programmes. In both the bureaucratic and technocratic systems, the agency of local farmers has remained weak and constrained. Both systems of management established formal development processes and power structures that largely sidelined meaningful contributions by ordinary farmers to technological change processes. We argue that the agency and capacities of farmers and rural communities, to make choices and respond to opportunities arising from or introduced into their local situations, should be recognised as an important engine of socio-eco-technical transformations towards a sustainable future for African agriculture. We therefore propose that this exploratory study helps to build a platform for further research both conceptually and methodologically, with the potential to inform the design and implementation of future agricultural development interventions