Dynamics of switching at stall reveals nonequilibrium mechanism in the allosteric regulation of the bacterial flagellar switch

Behavior of the bacterial flagellar motor depends sensitively on the external loads it drives. Motor switching, which provides the basis for the run-and-tumble behavior of flagellated bacteria, has been studied for motors under zero to high loads, revealing a non-equilibrium effect that is proportional to the motor torque. However, behavior of the motor switching at stall (with maximum torque) remains unclear. An extrapolation from previous studies would suggest maximum non-equilibrium effect for motor switching at stall. Here, we stalled the motor using optical tweezers and studied the motor switching with a high time resolution of about 2 ms. Surprisingly, our results showed exponentially distributed counterclockwise (CCW) and clockwise (CW) intervals, indicating that motor switching at stall is an equilibrium process. Combined with previous experiments at other loads, our result suggested that the non-equilibrium effect in motor switching arises from the asymmetry of the torque generation in the CCW and CW directions. By including this non-equilibrium effect in the general Ising-type conformation spread model of the flagellar switch, we consistently explained the motor switching over the whole range of load conditions.

Slow Household Deleveraging

We use a model of precautionary savings with housing and mortgages to study the effects of a deleveraging shock on consumer spending. We focus on the deleveraging caused by a contraction in home values, and compute numerically the partial-equilibrium effect of the shock. Our simulations show that household deleveraging is associated with a long and protracted weakness in consumption. These effects appear even if we assume, realistically, that housing wealth is illiquid and mortgage debt is long term. We show that housing wealth matters for consumption decisions due to an insurance force: consumers know they can sell their house if they get hit by sufficiently negative shocks in the future. We also show that our slow deleveraging mechanism is amplified when incomes are affected by a weak aggregate consumption demand through general-equilibrium effects.

Features of the Use of Equilibrium State Diagrams for Description of Crystal Growth from Metastable Melts

The crystallization of metastable metal alloys is characterized by a high rate of the crystallization front, which leads to the effect of "impurity capture" and deviation from the local equilibrium near the surface of the growing crystal. To calculate the growth rate of the crystalline nuclei, a method was developed for prediction of deviation of the components’ concentration near the crystal surface from the equilibrium values. A crystal nucleus was considered to be growing from the initial multicomponent phase, due to interphase transition of the components through its surface. It became possible to distinguish the equilibrium and non-equilibrium effect of the nucleus growth rate by decomposing the molar rate of the product formation near equilibrium, as a function of the molar concentration of the components in the Taylor series and limiting with the linear members. The practical calculations were carried out for the crystallization of the amorphous alloy Fe73,5Cu1Nb3Si13,5B9 of the FINEMET type. The local deviations were investigated for the silicon concentration from the equilibrium values at the surface of the growing crystal.

Equilibrium Effects of Health Care Price Information

Do information frictions in health care markets lead to higher prices and price dispersion? Focusing on medical imaging procedures, this paper examines the equilibrium effect of a unique statewide price transparency website. Price information leads to a shift to lower-cost providers, especially for patients subject to a deductible. Furthermore, supply-side effects play a significant role in the long run, benefiting all insured individuals. Supply-side effects reduce price dispersion and are especially relevant in concentrated markets. These effects are important given that high prices are thought to be a primary cause of high private health care spending.