Radar-Only Off-Road Local Navigation

Off-road robotics have traditionally utilized lidar for local navigation due to its accuracy and high resolution. However, the limitations of lidar, such as reduced performance in harsh environmental conditions and limited range, have prompted the exploration of alternative sensing technologies. This paper investigates the potential of radar for off-road local navigation, as it offers the advantages of a longer range and the ability to penetrate dust and light vegetation. We adapt existing lidar-based methods for radar and evaluate the performance in comparison to lidar under various off-road conditions. We show that radar can provide a significant range advantage over lidar while maintaining accuracy for both ground plane estimation and obstacle detection. And finally, we demonstrate successful autonomous navigation at a speed of 2.5 m/s over a path length of 350 m using only radar for ground plane estimation and obstacle detection.Comment: 7 pages, 17 figures, ITSC 202

Real-Time Monitoring of Bacterial Infection In Vivo: Development of Bioluminescent Staphylococcal Foreign-Body and Deep-Thigh-Wound Mouse Infection Models

Staphylococcal infections associated with catheter and prosthetic implants are difficult to eradicate and often lead to chronic infections. Development of novel antibacterial therapies requires simple, reliable, and relevant models for infection. Using bioluminescent Staphylococcus aureus, we have adapted the existing foreign-body and deep-wound mouse models of staphylococcal infection to allow real-time monitoring of the bacterial colonization of catheters or tissues. This approach also enables kinetic measurements of bacterial growth and clearance in each infected animal. Persistence of infection was observed throughout the course of the study until termination of the experiment at day 16 in a deep-wound model and day 21 in the foreign-body model, providing sufficient time to test the effects of antibacterial compounds. The usefulness of both animal models was assessed by using linezolid as a test compound and comparing bioluminescent measurements to bacterial counts. In the foreign-body model, a three-dose antibiotic regimen (2, 5, and 24 h after infection) resulted in a decrease in both luminescence and bacterial counts recovered from the implant compared to those of the mock-treated infected mice. In addition, linezolid treatment prevented the formation of subcutaneous abscesses, although it did not completely resolve the infection. In the thigh model, the same treatment regimen resulted in complete resolution of the luminescent signal, which correlated with clearance of the bacteria from the thighs

Whose Mass is it Anyway? Particle Cosmology and the Objects of Theory

Physicists in different branches of the discipline were puzzled by the problem of mass during the 1950s and 1960s: why do objects have mass? Around the same time, yet working independently, specialists in gravitational studies and in particle theory proposed that mass might arise due to objects’ interactions with a new (and as yet undetected) field. Although the questions they posed and even the answers they provided shared several similarities - and even though both proposals quickly became ‘hot topics’ in their respective subfields - virtually no one discussed one proposal in the light of the other for nearly 20 years. Only after massive, unprecedented changes in pedagogical infrastructure rocked the discipline in the early 1970s did a new generation of physicists begin to see possible links between the Brans-Dicke field and the Higgs field. For the new researchers, trained in different ways than most of their predecessors, the two objects of theory were not only similar - some began to proclaim that they were exactly the same. Charting the histories of these two objects of theory illuminates the complicated institutional and pedagogical factors that helped to produce a new subfield, particle cosmology, which today ranks at the very forefront of modern physics