Continuous control of an underground loader using deep reinforcement learning

Reinforcement learning control of an underground loader is investigated in simulated environment, using a multi-agent deep neural network approach. At the start of each loading cycle, one agent selects the dig position from a depth camera image of the pile of fragmented rock. A second agent is responsible for continuous control of the vehicle, with the goal of filling the bucket at the selected loading point, while avoiding collisions, getting stuck, or losing ground traction. It relies on motion and force sensors, as well as on camera and lidar. Using a soft actor-critic algorithm the agents learn policies for efficient bucket filling over many subsequent loading cycles, with clear ability to adapt to the changing environment. The best results, on average 75% of the max capacity, are obtained when including a penalty for energy usage in the reward.Comment: 9 pages, 7 figure

Trading Justice for Peace? Reframing reconciliation in TRC processes in South Africa, Canada and Nordic countries

Conflict in its various manifestations continues to be a defining feature in many places throughout the world. In an attempt to address such conflict, various forms of a Truth and Reconciliation Commission (TRC) have been introduced to facilitate the transition from social conflict to a new dispensation. The introduction and subsequent proceedings of TRCs in South Africa, Canada and Norway are widely regarded as good examples of this approach. Against this background, a number of researchers from VID Specialized University and the University of the Western Cape had an exploratory meeting in Oslo in 2018 where the possibility for a joint research project under the broad theme of ‘discourses on reconciliation’ was first discussed. This led to two further research symposia in Cape Town and Tromsø in 2019. With the inclusion of specialists working on the Canadian Truth and Reconciliation process, these meetings demonstrated common ground and a shared understanding of the issues at stake. Moreover, it pointed to the differences between the South African, Canadian and Norwegian Commissions. In comparing the South African, Canadian and Norwegian experiences, researchers identified that these countries were, in fact, at different stages of their respective truth and reconciliation processes. This has prompted scholars to revisit and problematise these processes in relation to ongoing societal challenges. In all cases, it is quite apparent that reconciliation between individuals and groups remains a significant challenge

Nitroimidazole Action in Entamoeba histolytica: A Central Role for Thioredoxin Reductase

Metronidazole, a 5-nitroimidazole drug, has been the gold standard for several decades in the treatment of infections with microaerophilic protist parasites, including Entamoeba histolytica. For activation, the drug must be chemically reduced, but little is known about the targets of the active metabolites. Applying two-dimensional gel electrophoresis and mass spectrometry, we searched for protein targets in E. histolytica. Of all proteins visualized, only five were found to form adducts with metronidazole metabolites: thioredoxin, thioredoxin reductase, superoxide dismutase, purine nucleoside phosphorylase, and a previously unknown protein. Recombinant thioredoxin reductase carrying the modification displayed reduced enzymatic activity. In treated cells, essential non-protein thiols such as free cysteine were also affected by covalent adduct formation, their levels being drastically reduced. Accordingly, addition of cysteine allowed E. histolytica to survive in the presence of otherwise lethal metronidazole concentrations and reduced protein adduct formation. Finally, we discovered that thioredoxin reductase reduces metronidazole and other nitro compounds, suggesting a new model of metronidazole activation in E. histolytica with a central role for thioredoxin reductase. By reducing metronidazole, the enzyme renders itself and associated thiol-containing proteins vulnerable to adduct formation. Because thioredoxin reductase is a ubiquitous enzyme, similar processes could occur in other eukaryotic or prokaryotic organisms