Brown-fat thermogenesis: recruiting the furnace

A cold drive past the spinodal would collapse the euthermic basin (the state falls to -1.4036). Recruiting the UCP1 furnace -- cold → ADRB3 command → uncoupled proton leak → heat -- adds a compensating flux that returns the NET drive below the spinodal, so the state is defended (1.0811).

RG1. Brown-fat thermogenesis is the active arm of setpoint defense: the furnace supplies the restoring flux that keeps the net cold drive sub-spinodal. Mechanism [V]; the BAT output rate is cited [L]; absolute W/kg is [O]. This is the {UCP1 + ADRB3} pair of Q1 doing its job.

Cold alone vs cold with the furnace

Without thermogenesis a supra-spinodal cold drive overwhelms the basin (True); with UCP1 recruited the compensating heat flux restores the setpoint (True). The command-effector pair from Q1 is exactly the machinery that supplies this flux.

Why ectotherms cannot do this

An organism lacking the drivable command pair has no way to inject this restoring flux on demand, so a supra-spinodal cold drive simply tracks -- the body cools with the environment. The gene criterion and the dynamics meet here.