Comparing policy gradient and value function based reinforcement learning methods in simulated electrical power trade

In electrical power engineering, reinforcement learning algorithms can be used to model the strategies of electricity market participants. However, traditional value function based reinforcement learning algorithms suffer from convergence issues when used with value function approximators. Function approximation is required in this domain to capture the characteristics of the complex and continuous multivariate problem space. The contribution of this paper is the comparison of policy gradient reinforcement learning methods, using artificial neural networks for policy function approximation, with traditional value function based methods in simulations of electricity trade. The methods are compared using an AC optimal power flow based power exchange auction market model and a reference electric power system model

Defining the role of mesenchymal stromal cells in treatment resistance in acute lymphoblastic leukaemia

The bone marrow microenvironment is crucial in treatment resistance in B-cell acute lymphoblastic leukaemia (B-ALL). Recent murine models suggest that treatment resistant cells are intrinsically no different to the treatment sensitive ‘bulk population’ but instead depend on a protective niche for survival. In this thesis I set out to investigate and model the mesenchymal stromal cell (MSC) niche in B-ALL. I initially showed, that MSC directly isolated from the primary bone marrow specimens of patients with B-ALL frequently adopted an activated or cancer associated fibroblast (CAF)-like phenotype. This was characterised by morphological changes, up-regulation of CAF relevant genes and enhanced cytokine/chemokine secretion. I uncovered a sub-set of B-ALL cell lines and primary B-ALL cells are capable of inducing the CAF-like phenotype in MSC cell lines and healthy donor MSC in vitro. These changes occur relative to the intrinsic reactive oxygen species (ROS) level and genetic sub-type of the B-ALL cell. Next, I showed that normal primary human MSC and the MSC cell line HS27a became activated de novo, when exposed to the reactive oxygen species (ROS)-inducing chemotherapy agents’ cytarabine (AraC) and daunorubicin (DNR). This phenomenon did not occur with non-ROS inducing chemotherapy - vincristine (VCR) and was blocked by NAC or the corticosteroid, dexamethasone. Finally, I demonstrated that activated MSC protected B-ALL cells from ROS-inducing chemotherapy via mitochondrial transfer through tunnelling nanotubes (TNT). Inhibition of mitochondrial transfer by selective mitochondrial depletion of MSC or interference with TNT formation by microtubule inhibitors such as VCR -prevented the ‘rescue’ function of the activated MSC. In summary, my thesis proposes a model in which the eradication of residual ALL cells by conventional chemotherapy is ineffective, at least in part due to MSC-mediated transfer of mitochondria to B-ALL cells to overcome chemotherapy induced oxidative stress at the MSC niche. My work proposes the clinically testable hypothesis that ROS inducing chemotherapies should always be combined with corticosteroids and/or microtubule inhibitors to overcome MSC mediated protection of B-ALL cells

Relationships Between Habitat and Snag Characteristics and the Reproductive Success of the Brown-headed Nuthatch (Sitta pusilla) in Eastern Texas.

Habitat use and reproductive success of the Brown-headed Nuthatch (Sitta pusilla Latham) were studied in East Texas during the 2001-2002 breeding seasons. We compared nest cavity selection at used and randomly selected non-used areas. Height of nest trees, midstory density, and percent leaf litter were negatively correlated with nest site selection. Brown-headed Nuthatches showed a strong preference for short snags; yet placed their nest cavity entrances near the top ofthe snags. While nuthatches may be selecting for habitats with little or no midstory density, percent of leaf litter in the nest sites is most likely the consequence of frequent burning. No significant differences among habitat variables and snag characteristics were found between successful and failed nest cavities. Additionally, no habitat variables were correlated with the number of chicks fledged per nest. Predation was the major cause of nest failure in this study

Growing olives in Western Australia

There are about 9 million hectares of olives in the world, with the largest areas in Spain, Italy, Greece and Tunisia. Olives are grown between the latitudes of 30° and 45° from the equator. In Australia, the main producing areas are between latitudes 31° and 38°S. Production in Western Australia ranges from Chapman Valley, Northampton (29.5°S), to Albany (34.5°S). Olive production has increased markedly in Australia in the past ten years with a large increase in managed investment scheme olive groves. The Moore River region of the Shire of Gingin accounts for over 70 per cent of olive trees and production in Western Australia. Large groves are also established at Frankland and West Beverley. Smaller groves have been planted in areas such as Geraldton, Margaret River, Peel, Warren and York.https://researchlibrary.agric.wa.gov.au/bulletins/1136/thumbnail.jp

Planning for future uncertainties in electric power generation : an analysis of transitional strategies for reduction of carbon and sulfur emissions

The object of this paper is to identify strategies for the U.S. electric utility industry for reduction of both acid rain producing and global warming gases. The research used the EPRI Electric Generation Expansion Analysis System (EGEAS) utility optimization/simulation modeling structure and the EPRI developed regional utilities. It focuses on the North East and East Central region of the U.S. Strategies identified were fuel switching -- predominantly between coal and natural gas, mandated emission limits, and a carbon tax. The overall conclusions of the study are that using less (conservation) will always benefit Carbon Emissions but may or may not benefit Acid Rain emissions by the offsetting forces of improved performance of new plant as opposed to reduced overall consumption of final product. Results of the study are highly utility and regional demand specific. The study showed, however, that significant reductions in both acid rain and global warming gas production could be achieved with relatively small increases in the overall cost of production of electricity and that the current dispatch logics available to the utility control rooms were adequate to reschedule dispatch to meet these objectives.Supported by teh MIT Center for Energy Policy Research

Ares Launch Vehicles Development Awakens Historic Test Stands at NASA's Marshall Space Flight Center

This paper chronicles the rebirth of two national rocket testing assets located at NASA's Marshall Space Flight Center: the Dynamic Test Stand (also known as the Ground Vibration Test Stand) and the Static Test Stand (also known as the Main Propulsion Test Stand). It will touch on the historical significance of these special facilities, while introducing the requirements driving modifications for testing a new generation space transportation system, which is set to come on line after the Space Shuttle is retired in 2010. In many ways, America's journey to explore the Moon begins at the Marshall Center, which is developing the Ares I crew launch vehicle and the Ares V cargo launch vehicle, along with managing the Lunar Precursor Robotic Program and leading the Lunar Lander descent stage work, among other Constellation Program assignments. An important component of this work is housed in Marshall's Engineering Directorate, which manages more than 40 facilities capable of a full spectrum of rocket and space transportation technology testing - from small components to full-up engine systems. The engineers and technicians who operate these test facilities have more than a thousand years of combined experience in this highly specialized field. Marshall has one of the few government test groups in the United States with responsibility for the overall performance of a test program from conception to completion. The Test Laboratory has facilities dating back to the early 1960s, when the test stands needed for the Apollo Program and other scientific endeavors were commissioned and built along the Marshall Center's southern boundary, with logistics access by air, railroad, and barge or boat on the Tennessee River. NASA and its industry partners are designing and developing a new human-rated system based on the requirements for safe, reliable, and cost-effective transportation solutions. Given below are summaries of the Dynamic Test Stand and the Static Test Stand capabilities, along with an introduction to the new missions that these sleeping giants will be fulfilling as NASA readies the Ares I for service in the 2015 timeframe, and plans the development work for fielding the Ares V late next decade (fig. 1). Validating modern computer design models and techniques requires the sorts of data that can only be generated by these one-of-a-kind facilities