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We investigated whether deep reinforcement learning (deep RL) is able to synthesize sophisticated and safe movement skills for a low-cost, miniature humanoid robot that can be composed into complex behavioral strategies. We used deep RL to train a humanoid robot to play a simplified one-versus-one soccer game. The resulting agent exhibits robust and dynamic movement skills, such as rapid fall recovery, walking, turning, and kicking, and it transitions between them in a smooth and efficient manner. It also learned to anticipate ball movements and block opponent shots. The agent's tactical behavior adapts to specific game contexts in a way that would be impractical to manually design. Our agent was trained in simulation and transferred to real robots zero-shot. A combination of sufficiently high-frequency control, targeted dynamics randomization, and perturbations during training enabled good-quality transfer. In experiments, the agent walked 181% faster, turned 302% faster, took 63% less time to get up, and kicked a ball 34% faster than a scripted baseline. Editor's summary: Generating robust motor skills in bipedal robots in the real world is challenging because of the inability of current control methods to generalize to specific tasks. Haarnoja et al. developed a deep reinforcement learning–based framework for full-body control of humanoid robots, enabling a game of one-versus-one soccer. The robots exhibited emergent behaviors in the form of dynamic motor skills such as the ability to recover from falls and also tactics like defending the ball against an opponent. The robot movements were faster when using their framework than a scripted baseline controller and may have potential for more complex multirobot interactions. —Amos Matsiko [ABSTRACT FROM AUTHOR]

Abstract Background Mathematical models based on kinetics of HIV-1 plasma viremia after initiation of combination antiretroviral therapy (cART) inferred HIV-infected cells to decay exponentially with constant rates correlated to their strength of virus production. To further define in vivo decay kinetics of HIV-1 infected cells experimentally, we assessed infected cell-classes of distinct viral transcriptional activity in peripheral blood mononuclear cells (PBMC) of five patients during 1 year after initiation of cART Results In a novel analytical approach patient-matched PCR for unspliced and multiply spliced viral RNAs was combined with limiting dilution analysis at the single cell level. This revealed that HIV-RNA+ PBMC can be stratified into four distinct viral transcriptional classes. Two overlapping cell-classes of high viral transcriptional activity, suggestive of a virion producing phenotype, rapidly declined to undetectable levels. Two cell classes expressing HIV-RNA at low and intermediate levels, presumably insufficient for virus production and occurring at frequencies exceeding those of productively infected cells matched definitions of HIV-latency. These cells persisted during cART. Nevertheless, during the first four weeks of therapy their kinetics resembled that of productively infected cells. Conclusion We have observed biphasic decays of latently HIV-infected cells of low and intermediate viral transcriptional activity with marked decreases in cell numbers shortly after initiation of therapy and complete persistence in later phases. A similar decay pattern was shared by cells with greatly enhanced viral transcriptional activity which showed a certain grade of levelling off before their disappearance. Thus it is conceivable that turnover/decay rates of HIV-infected PBMC may be intrinsically variable. In particular they might be accelerated by HIV-induced activation and reactivation of the viral life cycle and slowed down by the disappearance of such feedback-loops after initiation of cART.

A 34-year-old man from Ethiopia had been suffering from inflammatory lower back pain for five months. The imaging showed multiple osteolytic lesions histologically corresponding to a granulomatous inflammation. Detection of multiresistant Mycobacteria Tuberculosis (MDR-TBJ was delayed because of initially negative microbiological findings. During the therapy of MDR-TB, the patient developed different side effects. In this article we focus on the challenge to diagnose and treat MDR-TB also in a resource-rich setting as it is the case for Switzerland. [ABSTRACT FROM AUTHOR]