INCENTIVE MECHANISM FOR PERFORMANCE-BASED PAYMENT OF INFRASTRUCTURE PPP PROJECTS: COUPLING OF REPUTATION AND RATCHET EFFECTS

The performance-based payment PPP model has been widely used in the infrastructure projects. However, the ratchet effect derived from performance-based reputation incentives has been largely overlooked. To overcome this shortcoming, ratchet effect is considered in the performance-based payment incentive process. A multi-period dynamic incentive mechanism is developed by coupling the reputation and ratchet effect. The main results show that: (1) Under the coupling of reputation and ratchet effects, the optimal incentive coefficient in the last performance assessment period is always greater than that of the first period. The bargaining power can replace part of the incentive effect; (2) Due to the ratchet effect, if the government improve performance targets through performance adjustment coefficients, it needs to increase incentives to overcome the decreasing effort of the private sector; (3) When the bargaining power and punishment coefficient are small, the reputation incentive is replacing the explicit incentive. The increasing incentive coefficient would make the ratchet effect dominant the reputation effect; (4) To prevent the incentive incompatibility derived from the ratchet effect, the government should increase the incentive while increasing the punishment to achieve the “penalties and rewards”. This study provides theoretical and methodological guidance to design incentive contracts for infrastructure PPP projects.

Effects of verbal instruction vs. modelling on imitation and overimitation

Human culture is the result of a unique cumulative evolutionary process. Despite the importance of culture for our species the social transmission mechanisms underlying this process are still not fully understood. In particular, the role of language—another unique human behaviour—in social transmission is under-explored. In this first direct, systematic comparison of demonstration vs. language-based social learning, we ran transmission chains of participants (6- to 8-year-old children and adults from Cyprus) who attempted to extract a reward from a puzzle box after either watching a model demonstrate an action sequence or after listening to verbal instructions describing the action sequence. The initial seeded sequences included causally relevant and irrelevant actions allowing us to measure transmission fidelity and the accumulation of beneficial modifications through the lens of a subtractive ratchet effect. Overall, we found that, compared to demonstration, verbal instruction specifically enhanced the faithful transmission of causally irrelevant actions (overimitation) in children, but not in adults. Cumulative cultural evolution requires the faithful transmission of sophisticated, complex behaviour whose function may not be obvious. This indicates that, by supporting the retention of actions that appear to lack a causal function specifically by children, language may play a supportive role in cumulative cultural evolution.

Ratchet Effect in Import Prices – Inflation Rate Nexus

This study examined the existence of the ratchet effect in the import price-inflation rate nexus for advanced (high-income) and emerging (middle-income) countries. The study used monthly data from 1980M01 to 2019M07 and compared the potential of the dummy variable-based asymmetric model with that of the Nonlinear Autoregressive Distributed Lag (NARDL) model in modelling the ratchet effect. The result showed that the ratchet effect exists in the import price-inflation rate nexus for high-income and middle-income countries. This suggests that the issue of imported inflation and ratchet effect is country-specific. The significance of the ratchet effect in these countries implies that maintaining a (symmetric) rule-based counter-cyclical monetary policy when dealing with import price shocks would be inefficient, and can make monetary policy harm the economy in the medium to the long term. It is, therefore, recommended that each country should examine the existence or otherwise of ratchet in her import price - inflation rate nexus to determine whether it should adopt a symmetric or an asymmetric rule-based counter-cyclical monetary policy against import price shocks to avoid harming the economy through the implementation of an inefficient monetary policy.

Realization of macroscopic ratchet effect based on nonperiodic and uneven potentials

Ratchet devices allow turning an ac input signal into a dc output signal. A ratchet device is set by moving particles driven by zero averages forces on asymmetric potentials. Hybrid nanostructures combining artificially fabricated spin ice nanomagnet arrays with superconducting films have been identified as a good choice to develop ratchet nanodevices. In the current device, the asymmetric potentials are provided by charged Néel walls located in the vertices of spin ice magnetic honeycomb array, whereas the role of moving particles is played by superconducting vortices. We have experimentally obtained ratchet effect for different spin ice I configurations and for vortex lattice moving parallel or perpendicular to magnetic easy axes. Remarkably, the ratchet magnitudes are similar in all the experimental runs; i. e. different spin ice I configurations and in both relevant directions of the vortex lattice motion. We have simulated the interplay between vortex motion directions and a single asymmetric potential. It turns out vortices interact with uneven asymmetric potentials, since they move with trajectories crossing charged Néel walls with different orientations. Moreover, we have found out the asymmetric pair potentials which generate the local ratchet effect. In this rocking ratchet the particles (vortices) on the move are interacting each other (vortex lattice); therefore, the ratchet local effect turns into a global macroscopic effect. In summary, this ratchet device benefits from interacting particles moving in robust and topological protected type I spin ice landscapes.

Cancel Culture: Myth or Reality?

In recent years, a progressive “cancel culture” in society, right-wing politicians and commentators claim, has silenced alternative perspectives, ostracized contrarians, and eviscerated robust intellectual debate, with college campuses at the vanguard of this development. These arguments can be dismissed as rhetorical dog whistles devoid of substantive meaning, myths designed to fire up the MAGA faithful, outrage progressives, and distract from urgent real-world problems. Given heated contention, however, something more fundamental may be at work. To understand this phenomenon, the opening section defines the core concept and theorizes that perceptions of this phenomenon are likely to depend upon how far individual values fit the dominant group culture. Within academia, scholars most likely to perceive “silencing” are mismatched or non-congruent cases, where they are “fish-out-of-water.” The next section describes how empirical survey evidence is used to test this prediction within the discipline of political science. Data are derived from a global survey, the World of Political Science, 2019, involving almost 2500 scholars studying or working in over 100 countries. The next section describes the results. The conclusion summarizes the key findings and considers their broader implications. Overall, the evidence confirms the “fish-out-of-water” congruence thesis. As predicted, in post-industrial societies, characterized by predominately liberal social cultures, like the US, Sweden, and UK, right-wing scholars were most likely to perceive that they faced an increasingly chilly climate. By contrast, in developing societies characterized by more traditional moral cultures, like Nigeria, it was left-wing scholars who reported that a cancel culture had worsened. This contrast is consistent with Noelle-Neumann’s spiral of silence thesis, where mainstream values in any group gradually flourish to become the predominant culture, while, due to social pressures, dissenting minority voices become muted. The ratchet effect eventually muffles contrarians. The evidence suggests that the cancel culture is not simply a rhetorical myth; scholars may be less willing to speak up to defend their moral beliefs if they believe that their views are not widely shared by colleagues or the wider society to which they belong.

EXPRESS: Information Disclosure Policy and Its Implications: Ratcheting in Supply Chains

Fear of escalating input prices in response to retail success is a commonly-discussed phenomenon affecting supply chains. Such a ratchet effect arises when a retailer feels compelled to modify his investments to better serve the end customers in order to hide positive prospects and restrain future wholesale price hikes. In a two-period model of supply chain interactions, the authors demonstrate that such an endogenous ratchet effect can have multi-faceted reverberations. A retailer fearing price hikes may be tempted to curtail near-term profits to ensure favorable long-term pricing. In response, the supplier can use deep discounts in its initial wholesale prices to convince the retailer to focus on its short-run profits rather than long-run pricing concerns. These deep discounts not only encourage mutually beneficial investments but also alleviate double-marginalization inefficiencies along the supply chain. In light of these results, the authors demonstrate that the mandatory information disclosure policy to reduce the ratchet effect decreases total channel efficiency compared to the case without information disclosure, precisely because mandatory disclosure interrupts the healthy tension among supply chain partners. Thus, the model presents a scenario where ratcheting concerns can create a degree of self-enforcing cooperation that results in socially beneficial responses in supply chains.

Ratchet effect in brownian photomotors: symmetry constraints and going beyond them

The symmetry conditions have been derived for the occurrence of the ratchet effect in Brownian photomotors. To this end, spatiotemporal symmetry operations in vector transformations, coordinate and time shifts, and in the overdamped regime were applied to the average photomotor velocity taken as a functional of the coordinate- and time-dependent potential energy. As established, individual Brownian particles (molecules) can move directionally only provided a symmetrically distributed charge fluctuates in them and they are placed on the substrates with an antisymmetric charge distribution or, vice versa, they are characterized by antisymmetrically distributed charge fluctuations and are placed on symmetric substrates. The collective directed motion of orientation-averaged particles is possible only in the former case. If a particle charge distribution is described by a time dependence with the universal type of symmetry (i.e., simultaneously symmetric, antisymmetric, and shift-symmetric), an additional symmetry constraint on the ratchet functioning arises: the ratchet effect is ruled out in the overdamped regime but allowed for inertial moving particles if the charge distributions in both the particle and the substrate are neither symmetric nor antisymmetric. The effect of the universal type of symmetry is exemplified by dipole photomotors derived from donor-acceptor conjugated organic molecules. With a specific type of molecular photoexcitation and a specific relationship of the dipole moments in the ground and excited states, the ratchet effect becomes symmetry-forbidden. The forbiddenness can be removed by molecular polarization effects, which in this case become the predominant factor governing the direction of the motion and average velocity of photomotors. The estimated velocities of polarization photomotors are an order of magnitude larger than for known motor proteins and dipole Brownian photomotors. These results can be helpful in the purposeful molecular design of dipole photomotors.