The climate emergency and its dire impacts on frontline communities in the City of Los Angeles inspired the creation of the Climate Emergency Mobilization Office (CEMO) by January 2021, although the idea dates back to 2019. The office, guided by the principles of environmental justice, coordinates with the Mayor and City Council, and collaborates with City departments through meaningful engagement with frontline leaders and their communities. CEMO has also begun broader work to identify and enact equitable strategies and policies to prevent, mitigate, and undo impacts from past pollution and economic disinvestments, and to ensure that frontline communities have a strong voice in policy and decision-making in the City of Los Angeles. This work has been done in partnership with many advocacy groups, students, and scholars at UCLA including graduate-level Public Policy and Public Health students. Based on conversations between UCLA Urban Planning Professor Gregory Pierce, and Marta Segura, an agreement was reached for a “Comprehensive Project.” Thirteen graduate-level Urban Planning students worked with CEMO on heat equity planning and strategies over the course of UCLA academic year 2022-2023. This report reflects their efforts and the results of that partnership. The aim of this study was to identify gaps in the City’s intervention strategies that focus on populations most in need during extreme heat events: those who needed to make informational or emergency calls, bus transit riders, and those without indoor cooling access.

The opportunistic pathogen Pseudomonas aeruginosa explores surfaces using twitching motility powered by retractile extracellular filaments called type IV pili (T4P). Single cells twitch by sequential T4P extension, attachment, and retraction. How single cells coordinate T4P to efficiently navigate surfaces remains unclear. We demonstrate that P. aeruginosa actively directs twitching in the direction of mechanical input from T4P in a process called mechanotaxis. The Chp chemotaxis-like system controls the balance of forward and reverse twitching migration of single cells in response to the mechanical signal. Collisions between twitching cells stimulate reversals, but Chp mutants either always or never reverse. As a result, while wild-type cells colonize surfaces uniformly, collision-blind Chp mutants jam, demonstrating a function for mechanosensing in regulating group behavior. On surfaces, Chp senses T4P attachment at one pole, thereby sensing a spatially resolved signal. As a result, the Chp response regulators PilG and PilH control the polarization of the extension motor PilB. PilG stimulates polarization favoring forward migration, while PilH inhibits polarization, inducing reversal. Subcellular segregation of PilG and PilH efficiently orchestrates their antagonistic functions, ultimately enabling rapid reversals upon perturbations. The distinct localization of response regulators establishes a signaling landscape known as local excitation-global inhibition in higher-order organisms, identifying a conserved strategy to transduce spatially resolved signals.