Assessing Multi-Agent Reinforcement Learning Algorithms for Autonomous Sensor Resource Management

Unmanned aerial vehicles (UAVs) have applications in search and rescue operations and such operations could be more efficient by using appropriate artificial intelligence (AI) to enable a UAV agent to operate autonomously. Sensor resource management (SRM), which leverages capabilities across location intelligence, facilitates the efficient and effective use of UAVs and their sensors to complete a set of tasks. Furthermore, multiple UAVs, each with different sensor configurations, must be considered when maximizing mission effects. Instantiating operational autonomy for such teams requires considerable coordination. One AI approach relevant to this task is multi-agent reinforcement learning (MARL). However, MARL has seen limited prior use in SRM. This work evaluates the trade-space of MARL algorithms with respect to performing heterogeneous sensor resource management (SRM) tasks, considers the concept of evaluating MARL in a test and evaluation framework and compares a suit of algorithms with random and Bayesian hyperparameter optimization methods

Lumbopelvic Stability During a Single Leg Step Down Predicts Elbow Varus Torque During Baseball Pitching

During a baseball pitch, energy is transferred from the lower extremities through the lumbopelvic junction to produce ball velocity. Reduced lumbopelvic stability has been associated with elbow injury in pitchers, and commonly ulnar collateral ligament (UCL) tears. The primary biomechanical mechanism of UCL tears is high elbow varus torque. Understanding how decreased lumbopelvic stability influences the development of elbow varus torque could identify risk factors of UCL elbow injury. PURPOSE: Characterize the predictive ability of lumbopelvic stability on elbow varus torque during a baseball pitch. METHODS: NCAA Division 1 baseball players (N=44; 19.6+1.3yrs) participated. Pitchers threw ten fastballs from a mound to a catcher over regulation distance. Elbow varus torque was recorded using an inertial measurement unit and ball velocity was recorded with a radar gun. Pitchers also completed a single leg step down (SLSD) task. Triplanar kinematics were recorded for both legs, pelvis and trunk using inertial measurement units. Statistical analysis consisted of a cluster analysis, principal component analysis (PCA), and a multivariate logistic regression model to determine the relationship between lumbopelvic stability and elbow varus torque. RESULTS: Cluster analysis revealed 2 subgroups of pitchers: Low Torque-High Velocity and High Torque-Low Velocity. PCA analysis indicated 4 patterns of SLSD motion variability (principal components): 1-sagittal plane, 2-transverse plane, 3-frontal plane trail limb, and 4-frontal plane lead limb. Increased transverse plane motion of the trunk and pelvis predicted higher odds of belonging to the High Torque-Low Velocity cluster; trunk [Odds Ratio=2.9 (95%CI:1.1,8.0), p=0.036] and pelvis [Odds Ratio=2.6 (95%CI:1.1,6.0), p=0.031]. CONCLUSIONS: Lumbopelvic motion assessed during the SLSD in pitchers can identify deficits that predict high elbow varus torque and low ball velocity during the baseball pitch. Specifically, higher pelvis and trunk transverse plane motion was associated with pitchers in the High Torque-Low Velocity cluster. The SLSD provides an easily accessible method for coaches and clinicians to identify a potential risk factor related to increased elbow varus torque and UCL injury in pitchers

Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution.

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists

Active DNA demethylation in post-mitotic neurons: A reason for optimism

Over the last several years proteins involved in base excision repair (BER) have been implicated in active DNA demethylation. We review the literature supporting BER as a means of active DNA demethylation, and explain how the various components function and cooperate to remove the potentially most enduring means of epigenetic gene regulation. Recent evidence indicates that the same pathways implicated during periods of widespread DNA demethylation, such as the erasure of methyl marks in the paternal pronucleus soon after fertilization, are operational in post-mitotic neurons. Neuronal functional identities, defined here as the result of a combination of neuronal subtype, location, and synaptic connections are largely maintained through DNA methylation. Chronic mental illnesses, such as schizophrenia, may be the result of both altered neurotransmitter levels and neurons that have assumed dysfunctional neuronal identities. A limitation of most current psychopharmacological agents is their focus on the former, while not addressing the more profound latter pathophysiological process. Previously, it was believed that active DNA demethylation in post-mitotic neurons was rare if not impossible. If this were the case, then reversing the factors that maintain neuronal identity, would be highly unlikely. The emergence of an active DNA demethylation pathway in the brain is a reason for great optimism in psychiatry as it provides a means by which previously pathological neurons may be reprogrammed into a more favorable role. Agents targeting epigenetic processes have shown much promise in this regard, and may lead to substantial gains over traditional pharmacological approaches

Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution.

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists

Expanding the Diversity of Mycobacteriophages: Insights into Genome Architecture and Evolution

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists