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The state capacity-civil society tradeoff model tends to treat the "state" and "civil society" as separate entities who move to constrain one another. However, this modeling technique leaves out the nuances of individual action within a collective setting by treating each as a relative black box. This article explores this balance in the context of the surveillance state that has arisen in the 20th and 21st century. As state capacity in surveillance increases it better allows the state to respond to threats to citizens from citizens. However, the increased capacity also lessens the ability of societal pressure to check authoritarian advances even in a nation with a thriving civil society presence. [ABSTRACT FROM AUTHOR] more...

Hair follicles have recently emerged as promising drug delivery targets and gates for skin penetration. The so-called ratchet effect, which is based on an interaction between the hair shaft surface, the intrafollicular stratum corneum and nanoparticles, has proven to be very effective for the transport of active ingredients. Especially the nanoparticle-assisted decolonization of hair follicles constitutes an interesting new area of application. In a recently published work it was shown that small molecules as well as macromolecules solved in an outer phase of a formulation can be transported into the deeper parts of the hair follicles by adding nanoparticles to the formulation. In this case the nanoparticles constitute an entity independent of the drug and the transport is hypothesized to be based on an adhesion effect. In the present work, we focused on the impact of the particle concentration in the formulation on the transport efficiency of the model drug fluorescein sodium into hair follicles utilizing an ex vivo porcine skin model. It was observed that a particle concentration of 4% significantly enhances the transport efficiency of fluorescein as compared to 2% particle concentration. Doubling the concentration to 8% did not significantly increase the penetration depth. The effect evolved more efficiently when using 4 Hz circular motion massage as compared to 100 Hz oscillating massage. These results deliver interesting information on the optimal formulation as well as application parameters for a future application in clinical studies for e.g. skin antisepsis purposes. [ABSTRACT FROM AUTHOR] more...

This paper examines the relationship between income inequality and consumption, utilizing panel data from rural China over a span of four years to validate the application of relative income theory in the domain of food consumption. Food consumption represents a significant portion of expenditures for the low-income demographic and is of vital importance to China's food security and agricultural development. To ascertain the impact of income inequality on food consumption, this paper employs a bi-directional fixed-effects model, a mediation effect model, and machine learning causal analysis methods. Utilizing four years of rural resident survey data from the China Health and Nutrition Survey database, the study empirically tests the effect of income inequality on various types of food consumption, the channels through which it operates, and the heterogeneity among different income groups and educational backgrounds. The findings indicate that (1) income inequality within rural communities positively influences food consumption, and this conclusion remains robust under endogeneity treatment and robustness checks, positively affecting the transformation of food consumption and healthy intake; (2) income inequality among rural residents promotes food consumption through two mediating channels: the "demonstration effect" and the "ratchet effect;" (3) the impact of income inequality on food consumption exhibits heterogeneity among rural residents of different income levels and educational backgrounds. [ABSTRACT FROM AUTHOR] more...

Brownian motors belong to the class of nanoscale devices that use the thermal noise of the environment as one of the necessary components in the mechanism of their operation. Today, there are a lot of practical implementations of such nanomachines, both inorganic, fairly simple mechanisms produced artificially, and more complex ones created from separate biological components available at the cellular level. One of the options for implementing the mechanism of straightening the chaotic thermal noise of the environment into unidirectional motion is the presence of a motor particle in the field of action of an asymmetric periodic stationary potential, which undergoes certain small disturbances (fluctuations) periodically over time. To describe such asymmetric one-dimensional structures (for example, dipole chains or fibers of the cytoskeleton) in the theory of Brownian motors, two model potentials are most often used: piecewise linear sawtooth and double sinusoidal. In this work, within the framework of the approximation of small fluctuations, a model of a pulsating Brownian motor with a stationary double sinusoidal potential and a disturbing small harmonic signal is considered. A new method of parametrization of such a problem is proposed, which allows to separate the contributions from various factors affecting the operation of the ratchet, and the numerical procedure for calculating the average speed of the directional movement of nanoparticles for the selected type of model potentials is specified. A number of numerical dependences of the average speed on the main parameters of the system were obtained. Peculiarities of the behavior of the motor as dependent on the parameter responsible for asymmetry and the number of potential wells on the spatial period of the stationary potential have been investigated. It is shown that the direction of the generated flux of nanoparticles depends not only on the phase shift between the stationary and fluctuating components of the potential, but also on the temperature of the system and the frequency of fluctuations, i.e., a possibility of temperature-frequency control of the direction of movement in the considered model has been found. Diagrams have been constructed that allow you to choose the ratio between the parameters of the nanomotor to create a flux of particles in the desired direction. [ABSTRACT FROM AUTHOR] more...

Performance-based regulation (PBR) has recently experienced increased popularity in North America and Europe. The genesis for this renewed interest in PBR is the potential to strengthen the regulated firm's incentives for efficiency relative to traditional rate-of-return regulation. The strength of these incentives is referred to as the power of the regulatory regime (PRR). The PRR depends on the share of the efficiency gains retained by the regulated firm and the length of time that it retains them before being appropriated by the regulator acting as a surrogate for competition. Nonetheless, there are tradeoffs in the design of PBR plans that can render it inferior to traditional earning-based regulation in terms of incentive power. This may explain why the empirical evidence on the performance of PBR is best characterized as "mixed." [ABSTRACT FROM AUTHOR] more...

I study how private information on the evolution of preference interacts with the dynamic screening contracts in a principal-agent framework with short-term commitment. Privacy on the evolution of preference preserves the agent's future information advantage, even following truthful revelation of preference. This relaxes the ratchet effects if the consumer's initial preference is skewedly distributed and the evolution of preference is distributed sufficiently evenly, while it strengthens the ratchet effects if otherwise. Through its relaxation or strengthening of the ratchet effects, privacy on (im)persistency implies an improvement or distortion in the equilibrium revelation of preference. I also characterize the respective implications on the optimal contracts. Such privacy is not welcomed by all types of the agent, for it redistributes the information rent among different types. Privacy on the evolution of preference sustains in equilibrium, as it is not optimal for the principal to perfectly screen the (im)persistency per se. [ABSTRACT FROM AUTHOR] more...

Using current performance to set future targets can discourage effort and reduce performance. Our study examines whether this ratchet effect also undermines incentives of high-level managers and executives. We use a dynamic model to show that empirical tests used in prior literature can falsely reject the null hypothesis of no ratchet effect. We also motivate a new test that can better detect the adverse incentives effects of target setting. Specifically, we show that the ratchet effect can be identified as the effect of past performance on changes in perceived target difficulty. We use panel data from nine annual 2011–2019 surveys to implement this test. Similar to prior studies, we find strong evidence that targets are revised upward following good performance. Nevertheless, we reject the ratchet effect hypothesis because we further find that good performance in one period is associated with a decrease in perceived target difficulty in the next period. This finding is more pronounced in settings where well-performing managers have more private information about future performance and where long-term commitments are more credible. This paper was accepted by Suraj Srinivasan, accounting. Supplemental Material: The data files and online appendices are available at https://doi.org/10.1287/mnsc.2022.4641. [ABSTRACT FROM AUTHOR] more...

Time reversal asymmetry and spatial anisotropy are considered two prerequisites for Brownian ratchet. An intriguing realization can be achieved by placing an asymmetric gear in the suspension of motile rod-like bacteria. Usually, alignment interactions caused by anisotropic collisions or hydrodynamics would boost the ratchet effect. Here, we are concerned with a perfectly isotropic system, i.e., symmetric gear immersed in a bath of spherical active Brownian particles. We find that, under certain conditions, kinetic symmetry-breaking arises spontaneously, i.e., the symmetric gear keeps rotating in one direction. Unexpectedly, such ratchet phenomenon does not rely on the direct many-particle interactions and moreover the introduction of alignment interaction would counterintuitively prevent it from happening! Further investigation reveals that such spontaneous symmetry-breaking phenomenon shares similarities with the equilibrium phase transition of the Ising model. Our results provide new insights and enhance our understanding of the fundamental aspects of active ratchet phenomena. more...

This paper examines a two-period dynamic contracting in a supply chain under information asymmetry, where a supplier sells a product to a retailer via a trade credit contract. It is found that the retailer always prefers to conceal her actual cost information thus signal as a higher-cost type in the first period to pursue a higher information rent, which would decrease the supplier's profit and thereby the overall profit of the supply chain. To mitigate this ratchet effect, we introduce a reputation compensation mechanism in the two-period trade credit setting. This mechanism could alleviate the information asymmetry to a certain extent as there exists a threshold that incentivizes the retailer to share her true cost information in the earlier period. Moreover, the retailer might claim as a lower-cost type when the supplier offers a relatively higher reputation compensation to take full advantage of her information. Therefore, the supplier should provide trade credit with a reasonable reputation compensation in a two-period setting to enhance his expected profit. [ABSTRACT FROM AUTHOR] more...

This article explores how compartmentalised diplomacy, defined as the compartmentalisation of a comprehensive set of previously linked issues into separate but gradually and substantively expanding issues, helps forge an agreement on contested issues among member states in the United Nations Security Council. Based on a strategic bargaining framework, the article argues that subtracting issues from a comprehensive negotiation serves to create compartmentalised issues disassociated from other issues negotiated in the same context. Once an issue is separated, Council members may exploit a ratchet effect to expand a subtracted issue beyond what veto players initially may have preferred. Based on documentation by the non-profit organisation Security Council Report and news sources, an in-depth case study of Security Council action regarding Syria demonstrates how compartmentalised diplomacy helps Security Council members to forge landmark agreements on several contentious issues, even if members chiefly disagree on other issues. For comparative leverage and to assess the limits of the proposed mechanism, the analysis is briefly extended to other high-profile cases discussed in the Security Council (Sudan and Ukraine). The findings have implications for this essential tool of the Security Council to react to threats to peace. [ABSTRACT FROM AUTHOR] more...

Directed motion of a sphere immersed in a viscous fluid and subjected solely to a nonlinear drag force and zero-average biharmonic forces is studied in the absence of any periodic substrate potential. We consider the case of two mutually perpendicular sinusoidal forces of periods T and T/2, respectively, which cannot yield any ratchet effect when acting separately, while inducing directed motion by acting simultaneously. Remarkably and unexpectedly, the dependence on the relative amplitude of the two sinusoidal forces of the average terminal velocity is theoretically explained from the theory of ratchet universality, while extensive numerical simulations confirmed its predictions in the adiabatic limit. Additionally, the dependence on the dimensionless driving frequency of the dimensionless average terminal velocity far from the adiabatic limit is qualitatively explained with the aid of the vibrational mechanics approach. [ABSTRACT FROM AUTHOR] more...

This paper examines the relationship between income inequality and consumption, utilizing panel data from rural China over a span of four years to validate the application of relative income theory in the domain of food consumption. Food consumption represents a significant portion of expenditures for the low-income demographic and is of vital importance to China’s food security and agricultural development. To ascertain the impact of income inequality on food consumption, this paper employs a bi-directional fixed-effects model, a mediation effect model, and machine learning causal analysis methods. Utilizing four years of rural resident survey data from the China Health and Nutrition Survey database, the study empirically tests the effect of income inequality on various types of food consumption, the channels through which it operates, and the heterogeneity among different income groups and educational backgrounds. The findings indicate that (1) income inequality within rural communities positively influences food consumption, and this conclusion remains robust under endogeneity treatment and robustness checks, positively affecting the transformation of food consumption and healthy intake; (2) income inequality among rural residents promotes food consumption through two mediating channels: the “demonstration effect” and the “ratchet effect;” (3) the impact of income inequality on food consumption exhibits heterogeneity among rural residents of different income levels and educational backgrounds. more...

A mere few decades ago, culture was thought a unique human attribute. Evidence to the contrary accumulated through the latter part of the twentieth century and has exploded in the present one, demonstrating the transmission of traditions through social learning across all principal vertebrate taxa and even invertebrates, notably insects. The scope of human culture is nevertheless highly distinctive. What makes our cultural capacities and their cognitive underpinnings so different? In this article I argue that in behavioural scientists' endeavours to answer this question, fruitful research pathways and their ensuing discoveries have come to exist alongside popular, yet in the light of current empirical evidence, highly questionable scenarios and even scientific blind alleys. I particularly re-evaluate theories that rely on the centrality of a supposed uniquely human capacity for imitative copying in explaining the distinctive capacity for massive cumulative cultural evolution (CCE) in our species. The most extreme versions of this perspective suffer logical incoherence and severe limits on scientific testability. By contrast the field has generated a range of rigorous observational and experimental methodologies that have revealed both long-term cultural fidelity and limited forms of CCE in non-human species. Attention now turns to directly investigating the scope, limits and underlying cognition of non-human versus human CCE, with a broader approach to factors additional to cultural transmission, notably the role of invention, innovation and evolved motivational biases underlying the scope of CCE in the species studied. • Accumulating evidence demonstrates both culture and cumulative culture in animals. • In this light I offer a re-evaluation of contrasts between human and animal culture. • I argue that multiple popular theories range from shaky to misleading. • A suite of methodological advances is nevertheless yielding significant advances. • A specific focus now emerges in the comparative study of cumulative culture itself. [ABSTRACT FROM AUTHOR] more...

The main goal of this paper is to investigate whether (and how) humans are unique in using tools and artifacts. Non-human animals exhibit some impressive instances of tool and artifact-use. Chimpanzees use sticks to get termites out of a mound, beavers build dams, birds make nests, spiders create webs, bowerbirds make bowers to impress potential mates, etc. There is no doubt that some animals modify and use objects in clever and sophisticated ways. But how does this relate to the way in which humans make and use objects to achieve their goals? To answer this question, this paper first presents a taxonomy of artifacts, identifying four overlapping categories, namely embodied, perceptual, cognitive, and affective artifacts. It then discusses definitions of animal tool-use, arguing that we need a more liberal approach, one that goes beyond the use of tools that are embedded in occurrent perception-action cycles. This paper ends by analysing how instances of animal tool and artifact-use can be classified according to the four identified categories, concluding that some animals use embodied, perceptual, cognitive, and affective artifacts. In this sense, humans are thus not unique in the kinds of tools and artifacts we use. What is unique, however, is our unprecedented flexibility and openness to deeply incorporate a large variety of complex tools and artifacts into our embodied, perceptual, cognitive, and affective systems. [ABSTRACT FROM AUTHOR] more...

Copyright of Education Policy Analysis Archives / Archivos Analíticos de Políticas Educativas / Arquivos Analíticos de Políticas Educativas is the property of Educational Policy Analysis Archives & Education Review and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

We numerically investigate the anomalous transports of an inertial Brownian particle moving in a spatial-periodic symmetric system under the influence of a time-periodic force and a constant bias. The system is also driven by nonequilibrium fluctuation and friction fluctuation, which are correlated with each other. We find that a time-periodic force plays a key role in anomalous transports and that the correlation between noises can enhance, weaken, or lead to negative mobility (NM) and ratchet effect (RE). Moreover, our findings suggest that NM can be tuned by friction and Gaussian noise in certain parameter ranges and explained by the temporally periodic transient probability distributions (TPTPD) of the particle's velocity and position, average trajectory, and time-dependent diffusion coefficient (TDDC). The TPTPD reveals that system dynamics is sensitive to the initial conditions and system parameters. Initial transient states display that the particle undergoes superdiffusion firstly and then becomes normal diffusion. Additionally, the small TDDC corresponds to anomalous mobility, whereas the large TDDC corresponds to normal mobility. To obtain more intuition and generality, we also study the mobilities via the mobility coefficient. Our findings may be applied for particles sorting, particles separation, control of molecular motors, etc. [ABSTRACT FROM AUTHOR] more...

The ratchet effect is a directed nanoparticle flux phenomenon induced by nonequilibrium fluctuations in a system with spatial and (or) temporal asymmetry. One is used as the way to create a controlled nanotransport and is the basis of the theory of Brownian motors. Fluctuation motion simulation is a promising way to calculate the main characteristics of Brownian motors, it avoids complex calculations and quickly obtains predictions about the appearance or absence of generated directional motion in a specific model. Nonequilibrium fluctuations are usually introduced into the system by a dichotomous process that switches two periodic asymmetric potential profiles at certain fixed intervals (deterministic process), or randomly with average potential lifetimes (stochastic process). We investigate the modeling of the process of the ratchet effect in the framework of the Brownian motor jump-like model by the method of Parrondo’s paradoxical game for the stochastic dichotomous process and compare results with a similar deterministic process. A calculus method for the main characteristics obtaining of the motor with stochastic dichotomous process is proposed, it is shown correspondence to the analytical description of this model in extreme cases. It is shown that the stochasticity of the process directly affects the characteristics of the ratchet effect: the trajectories of the average displacements of nanoparticles fundamentally differs in the deterministic description, and a gradual difference in these processes is observed at low values. The study of asymmetric dichotomous processes for different temperature modes of motor operation is carried out. The model allows one to analyze the peculiarities of the directional motion starting at the level of single jumps, as well as to formulate recommendations for possible improvement of motor efficiency for different temperatures. For high-temperature mode, it is advisable to reduce the lifetime of the state with the active potential, and for low-temperature mode, arbitrary, it should be increased. [ABSTRACT FROM AUTHOR] more...

In this paper panel analysis is being carried on original Relative Income Hypothesis (RIH) and its other modifications over the time span of 1998 to 2015. To furnish reliable and appropriate estimation, Households Integrated Economic Surveys (HIES) based consumption and income variables have been gone through various stages of data filtering. The findings of Feasible Generalized Least Squares (FGLS) significantly validate the relevance of three types of ratchet effects (income, consumption and habit) in provinces. Average Propensity to Consume is highest for Baluchi's households followed respectively by Pashtuns, Punjabi, and Sindhi. The selection of constant slop model implies that province-wise there is no difference in magnitudes of ratchet effect obtained from various versions of RIH. All provinces make adjustments in long run to their consumption in response to income fluctuations. Estimated marginal consumption propensities are according to economic theory that shows smooth consumption path in short run as well in the long run. Polices should be formulated to switch consumer mind set from consumption oriented to saving oriented with the help of appropriate tool of fiscal and monetary policies. [ABSTRACT FROM AUTHOR] more...

The current indiscriminate use of antibiotics for veterinary is irresponsible and misguided; it causes antibiotic resistance and adversely affects public health. The terms “habit” and “path dependence” are often used to explain the “excessive” use of agrochemicals. Yet, no research explored where the habit comes from and how it changes. This study investigates how veterinary antibiotic use changed with the production risk based on the multi-period production data set of 1,526 broiler contract farmers. The results show that the production risk has a ratchet effect on farmers' antibiotic use, leading to path dependence of farmers. Specifically, it showed a farmers' habit of steadily increasing antibiotic use and confirmed that the historical broilers' peak mortality was a key determinant to the continuation of this habit. It implies that higher the historical peak mortality, higher the current antibiotic use by farmers. Likewise, the impact of historical peak mortality on antibiotic use gradually increased with the farming experience. The increased historical peak mortality increased farmers' antibiotic use every time. Furthermore, large-scale farmers were more sensitive to historical peak mortality and therefore they increased antibiotic use excessively. The study suggests that improving farmers' production risk management capabilities, especially large-scale farmers, might help prevent extreme events. Moreover, this work contributes to the theoretical and empirical evidence on the ratchet effect, habit formation and farmers' antibiotic use and offers coherent insights for stakeholders to limit antibiotic use. more...

The main prerequisites necessary for the construction of molecular motors, in particular, organic compound-based light-driven motors, are considered and universal requirements for their operation are formulated. Various types of Brownian motors differing in the forms of directed motion are analyzed. Development prospects and molecular design strategies are provided for such nanodevices. [ABSTRACT FROM AUTHOR] more...

We describe an optomechanical ratchet scheme to realize nonreciprocal transmission of a light field, which is based on the bias of the optical cavity's frequency spectrum caused by mechanical ratchet interactions. This approach to break the time-reversal symmetry of light propagation is universally valid in various optomechanical systems with ratchet-oscillator structures. We discuss specifically the implementation of an on-chip Casimir-ratchet optomechanical protocol and demonstrate the optical nonreciprocity with an extremely high isolation ratio and flexible controllability, which does not require external additional optical engineering. Our study opens a door for manipulating flexibly light propagation by using mechanical ratchet resonators, and has potential applications in the on-chip integration of nonreciprocal devices and harness of lateral Casimir forces. [ABSTRACT FROM AUTHOR] more...

Copyright of Journal of Engineering Management / Gongcheng Guanli Xuebao is the property of Journal of Engineering Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

Population size has been proposed to promote cumulative culture in humans. Experimental evidence from adult humans suggests that one explanatory mechanism might involve combining beneficial information from multiple models. However, it is possible that such combinatory social learning requires cognitive capacities restricted to adult humans. In our task, children aged 5-10 were exposed to two models who consecutively searched a 333 array for rewards. Models revealed different correct and incorrect reward locations. This information could be used by the child to maximise their own score on the same task. We were interested in children's ability to select rewarded locations, and avoid unrewarded ones, revealed by both models. We also manipulated the spatial and temporal displacement of the information available. Results showed that the youngest children were unable to fully benefit from the additional information provided by the two models under spatial and/or temporal displacement. Such displacement likely applies in most real-world cases of cumulative culture therefore our result may offer insight into the constraints on cumulative culture in nonhumans. [ABSTRACT FROM AUTHOR] more...

• Shear flows in vibrated granular materials were experimentally studied. • Viscosity transitions and non-Newtonian behaviors occur in granular shear flows. • Two non-Newtonian fluid models were used to compare with experimental results. • Viscosity–temperature relationship reveals granular gas-like behaviors. • These findings were explained based on the mechanism of viscosity generation. In a continuous fluid, the presence of a velocity gradient perpendicular to the flow creates shear stress and shear rate between adjacent layers. The fluid's viscosity can be constant, depending only on temperature (Newtonian fluid), or vary with shear rate (non-Newtonian fluid). However, the viscosity characteristics of shear flows in discrete media, such as vibrated granular materials, remain insufficiently understood. This study experimentally investigated shear flows in vibrated granular media, exploring the relationship between shear stress, shear rate, and the impact of vibration conditions and particle number on granular viscosity. The findings indicate that the viscosity of sheared granular material transitions between dilatant and pseudoplastic non-Newtonian states with increasing vibration strength, shifts from pseudoplastic non-Newtonian fluid to Newtonian fluid with increasing vibration frequency, and remains consistently pseudoplastic non-Newtonian with increasing particle number. Two continuous non-Newtonian fluid models were utilized for comparison with our experimental results. Additionally, ascending curves of granular viscosity against granular temperature reveal gas-like flow characteristics in the sheared granular material, albeit with an abnormal descending viscosity–temperature relationship. These are attributed to volume expansion and oblique collisions in the vibrated granular medium. This study uncovers distinct viscosity properties in a discrete medium under shear flows, markedly different from those in continuous fluids, and highlights potential new applications for granular materials. [Display omitted] [ABSTRACT FROM AUTHOR] more...

This paper endogenizes a monopolist's choice between selling and renting in a non-anonymous durable goods setting with short-term commitment, by allowing for contracts that determine the good's allocation not only at the beginning but also at the end of a given period. We show that the revenue-maximizing menu of contracts features screening by mode of trade when future trade is subject to frictions and the monopolist is more patient than consumers. Selling to high types while renting to low types, allows the monopolist to defer part of his compensation in form of a reduction of consumers' future information rents while lowering the allocational costs of ordinary, intertemporal screening. [ABSTRACT FROM AUTHOR] more...

In this paper, we investigate whether dynamic incentive schemes lead to a ratchet effect in a social dilemma. We test whether subjects strategically restrict their contribution levels at the beginning of a cumulative public goods game in order to avoid high obligations in the future and how this affects efficiency. The incentive schemes prescribe that individual contributions have to be at least as high as, or strictly higher than, contributions in the previous period. We observe a substantial and statistically significant ratchet effect. Participants reduce their public good contribution levels at the beginning of the game, anticipating that higher contributions imply higher minimum contribution levels in the future, which increases the risk of being exploited by free-riders. While the dynamic incentive schemes lead to increasing contribution levels over the course of the game, this increase is not strong enough to compensate the efficiency losses at the beginning. [ABSTRACT FROM AUTHOR] more...

We show the existence and properties of an exact universal excitation waveform for optimal enhancement of directed ratchet transport (in the sense of the average velocity) by providing three alternative derivations. Specifically, it is deduced from the criticality scenario giving rise to ratchet universality as well as from an approach based on Fokker–Planck's equation. Numerical experiments confirmed the existence of such exact universal excitation waveform in the context of a driven overdamped Brownian particle subjected to a periodic potential. While the universality scenario holds regardless of the waveform of the periodic vibratory excitations involved, it is shown that the enhancement of directed ratchet transport is optimal when the impulse transmitted by those excitations (time integral over a half-period) is maximum. [ABSTRACT FROM AUTHOR] more...

In our recent article, "Where Does Cumulative Culture Begin? A Plea for a Sociologically Informed Perspective" (Haidle and Schlaudt in Biol Theory 15:161–174, 2020) we commented on a fundamental notion in current approaches to cultural evolution, the "zones of latent solutions" (henceforth ZLS), and proposed a modification of it, namely a social and dynamic interpretation of the latent solutions which were originally introduced within an individualistic framework and as static, genetically fixed entities. This modification seemed, and still seems, relevant to us and, in particular, more adequate for coping with the archaeological record. Bandini et al. (Biol Theory, 2021) rejected our proposition and deemed it unnecessary. In their critique, they focused on: (1) our reservations about an individualistic approach; (2) our objections to the presumption of fully naive individuals; and (3) our demand for an extended consideration of forms of social learning simpler than emulation and imitation. We will briefly reply to their critique in order to clarify some misunderstandings. However, the criticisms also show that we are at an impasse on certain crucial topics, such as the meaning of ZLS and the scope and nature of culture in general. Thus, we consider it necessary to make an additional effort to identify the conceptual roots which are at the very basis of the dissent with Bandini et al. [ABSTRACT FROM AUTHOR] more...

The critical examination of current hypotheses is one of the key ways in which scientific fields develop and grow. Therefore, any critique, including Haidle and Schlaudt's article, "Where Does Cumulative Culture Begin? A Plea for a Sociologically Informed Perspective," represents a welcome addition to the literature. However, critiques must also be evaluated. In their article, Haidle and Schlaudt (Biol Theory 15:161–174, 2020. https://doi.org/10.1007/s13752-020-00351-w; henceforth H&S) review some approaches to culture and cumulative culture in both human and nonhuman primates. H&S discuss the "zone of latent solutions" (ZLS) hypothesis as applied to nonhuman primates and stone-toolmaking premodern hominins. Here, we will evaluate whether H&S's critique addresses its target. [ABSTRACT FROM AUTHOR] more...

Steam pipe failure is a problem that may affect refinery production and personal safety. It has practical significance for engineers who need to find out how to prevent such failure. This paper reports on a pipe bursting accident in a steam network. An investigation to identify the root causes of the failed steam pipe was carried out by macro inspections, chemical composition analysis, metallographic microscopy, scanning electron microscope (SEM) images, and energy dispersive spectroscope (EDS) analysis. The results showed that the chemical composition and mechanical properties were within the related standards, a combination of the ratchet effect and material creep causing the pipe wall thinning was the major failure root, and spheroidization of pearlite in the material also contributed to the failure. [ABSTRACT FROM AUTHOR] more...

We study directed ratchet transport of a harmonically driven overdamped Brownian particle subjected to a harmonically shaken periodic potential. The existence of a frequency-dependent optimal value of the relative amplitude of the two harmonic excitations involved is theoretically predicted from the criticality scenario giving rise to ratchet universality and numerically confirmed by extensive numerical experiments. The robustness of the ratchet universality scenario is also demonstrated when the external harmonic excitation is replaced by a bounded chaotic excitation having the same underlying main frequency in its Fourier spectrum. We remark that our findings are in sharp contrast with the predictions from the standard harmonic-mixing perturbation theory. [ABSTRACT FROM AUTHOR] more...

Perhaps the most contentious part of the response to the Covid-19 pandemic has been the decision by governments to mandate--or effectively mandate--the shutdown of certain businesses. The justification for doing so is broadly consequentialist. The public health costs of not shutting down are so great that potential benefits from allowing businesses to open are dwarfed. Operating within this consequentialist framework, this paper identifies an underappreciated set of social costs that are a product of the present public policy that pairs mandated shutdowns with government subsidies. Such policy is prone to being an instance of what Robert Higgs calls the ratchet effect. Given that ratchets tend to be both costly and sticky, it is best to avoid allowing them to come into existence. This paper identifies a way of circumventing this particular ratchet; namely, by replacing governmental subsidies with support from private charitable funds like The Barstool Fund. [ABSTRACT FROM AUTHOR] more...

The article - is description of Nobel prizes on economy. Nobel Prize in Economics “For the development of the theory of contracts” went to American professors Oliver Hart and Bengt Hallstrom. O. Hart was born in the UK, Swede B. Holmstrom - in Finland. Nevertheless, the history of the two laureates has more to do with the United States than with the historical homeland. Short CV of winners are presented, and summary of contract theory is described. Particular emphasis has been placed on agents opportunistic behavior and on winners works on soviet economic reforms of 1960’s years. more...

The human hair follicle (HF) represents a promising drug delivery target as an anatomical entity by itself, but also as a gateway enabling dermal or systemic bioavailability of active cosmetic and pharmaceutical ingredients. Due to its morphological characteristics, the HF provides a mechanically driven transport process of nanoparticles (NPs) when external forces are applied. This mechanism was presented as the so-called ratchet effect within the framework of an in silico study published recently. To investigate the influence of massage frequency on the penetration depth of NPs, and, by this, to validate the results obtained in silico , we implemented a corresponding application protocol on an ex vivo porcine skin model. In this connection, we compared three different skin massage frequencies (4.2 Hz, 50 Hz, 100 Hz) for the topical application of cyanine 5-labeled silica NPs (Cy5-SNPs). To elucidate the interplay of frequency and particle size, we furthermore applied Cy5-SNPs of three different diameters (300 nm, 676 nm, 1000 nm). Confocal laser scanning microscopy was utilized to investigate the follicular penetration depth of Cy5-SNPs on cryohistological slices. By this, we could demonstrate that the massage frequency and the follicular penetration depth exhibit an inverse relation pattern. Thus, the highest follicular penetration depth was observed within the 4.2 Hz group, while the lowest follicular penetration depth was found within the 100 Hz group for each Cy5-SNP size category. Additionally, we found that 676 nm Cy5-SNPs penetrated significantly deeper into HFs than 300 nm Cy5-SNPs and 1000 nm Cy5-SNPs, respectively. Summarizing, our results show that a low massage frequency including a dominant radial direction component leads to deeper follicular penetration depths of NPs than automated 3D-oscillation massage at 50 Hz or 100 Hz. Thus, our findings are in line with recent in silico results. Regarding translational purposes, our results are of high interest, since a massage executed at 250 BPM (4.2 Hz) is within a realizable range for manual application, e.g. for the implementation into clinical routines or the domestic use of drugs or cosmetics. Furthermore, the application of different massage frequencies offers the opportunity of patho-specific targeting as different anatomical parts of the HF can be reached. [ABSTRACT FROM AUTHOR] more...

This paper analyzes the possibility of obtaining the selective transport of microparticles suspended in air in a microgravity environment through modulated channels without net displacement of air. Using numerical simulation and bifurcation analysis tools, we show the existence of intermittent particle drift under the Stokes assumption of the fluid flow. The particle transport can be selective and the direction of transport is controlled only by the kind of pumping used. The selective transport is interpreted as a deterministic ratchet effect due to spatial variations in the flow and the particle drag. This ratchet phenomenon could be applied to the selective transport of metal particles during the short duration of microgravity experiments. [ABSTRACT FROM AUTHOR] more...

• We explore the effect of Job Rotation on the Ratchet Effect. • We compare the effectiveness between exogenous rotation and endogenous rotation. • We implement a controlled lab experiment to test the theoretical predictions. • Both methods reduce the Ratchet Effect with exogenous rotation being more powerful. • We find firms choose to rotate workers even this hurts their expected payoff. Regularly rotating agents between jobs in firms may lower the ratchet effect. Specifically, job rotation could disentangle the influence of current performance on agents' future incentives. In this paper, we conduct a controlled experiment to test the effectiveness of job rotation in eliminating the ratchet effect. Additionally, we compare effort provision between the situation where agents are rotated exogenously and the situation where the principal rotates agents endogenously. We find that the ratchet effect is effectively reduced when workers are informed that they will be rotated in the future. Contrary to the theoretical prediction, the ratchet effect is also significantly reduced when a principal has a costly option of rotating agents. [ABSTRACT FROM AUTHOR] more...

Recent field studies have broadened our view on cultural performances in animals. This has consequences for the concept of cumulative culture. Here, we deconstruct the common individualist and differential approaches to culture. Individualistic approaches to the study of cultural evolution are shown to be problematic, because culture cannot be reduced to factors on the micro level of individual behavior (methodological individualism, "atomism") but possesses a dynamic that only occurs on the group level and profoundly affects the individuals ("holism"). Naive individuals, as a prerequisite of an atomistic perspective, do not exist. We address the construction of a social approach to (cumulative) culture by introducing an inevitable social embedding of the individual development of social beings. The sociological notion of "habitus" as embodied cultural capital permits us to understand social transmission of behavioral components on a very basic level, resulting in a cumulative effect. Bits of information, movement, handling of material, attitudes, and preferences below distinct functional units are acquired through transfer mechanisms simpler than emulation and imitation such as peering, participation, co-performance, or engagement with a material environment altered by group members. The search for a zero point of cumulative culture becomes as useless as the search for a zero point of culture. Culture is cumulative. [ABSTRACT FROM AUTHOR] more...

A relevant and important question in studying the transport of nanoparticles is the possibility and methods of controlling the generated currents. One of the possibilities is to use the ratchet effect, i.e. the occurrence of directed motion as a result of the influence of nonequilibrium fluctuations of various nature when one or more symmetries in the system are broken. To implement the ratchet effect, a deterministic dichotomous process is often used, which can be modeled by two alternating states that have constant characteristics. Usually, the main factor determining the direction of motion of a Brownian motor is the spatial asymmetry of the potential profile. In certain cases, for example, for a double-well potential profile, one can relatively easily investigate the conditions for reversal of the direction of motor motion. In this paper, using the idea of Parrondo’s paradox games consisting of alternating strategies of a game that provides an average winning, we simulated the ratchet effect for a diffusion hopping model of an adiabatic Brownian motor with an asymmetric double-well on-off potential. The conditions affecting the direction of nanoparticle motion are investigated, the possibility of temperature control of the motion direction is shown, and an estimate of the generated average velocity of the Brownian motor in the adiabatic approximation is obtained. The motor functioning is simulated in terms of the game theory and the average trajectories of capital accumulation are obtained, which correspond to the trajectories of the average displacement of a Brownian particle due to the ratchet effect. For the chosen model, it is shown that, at low temperatures, a particle moves to the right in accordance with the simplest on-off ratchet model, while, at high temperatures, the motion reverses. A comparison of the simulation results with the values of the ratchet velocity obtained within the adiabatic approximation shows that this approximation becomes valid at sufficiently large values of the lifetimes of the states of the dichotomous process, and it turns out to be much more accurate in the high-temperature region than in the low-temperature one. [ABSTRACT FROM AUTHOR] more...

Brownian motors are a class of nanomechanisms that generate directional motion of Brownian particles under nonequilibrium perturbations. A symmetry analysis of the factors affecting the appearance of a directed current and determining its direction indicates the dependence of the motor characteristics on the phase shift between the potential reliefs of the stationary and fluctuating components of nanoparticle potential energy. The motion of a Brownian particle located in the field of action of an extremely asymmetric stationary sawtooth potential fluctuating as a result of dichotomous effects of spatially harmonic signal is considered. Since the sawtooth potential is easily realized near a surface with a series of electrodes of a certain shape buried inside it, and the dichotomous changes of a spatially harmonic signal are easily created by laser beams, the considered motion of a nanoparticle (Brownian motor) can be realized experimentally. It is known that at sufficiently high temperatures, when the thermal energy exceeds the energy barrier of the sawtooth potential, the direction of motion is determined exclusively by the phase shift of the harmonic signal relative to the extrema of the sawtooth potential. In this article, an analytical expression for the motor average velocity has been obtained, which is valid at arbitrary temperatures, but at low frequencies of dichotomous fluctuations (adiabatic mode). An analysis of the expression has shown that there exists a critical temperature Tc below which the direction of motion loses its dependence on the magnitude of the phase shift, whereas at T > Tc the direction of motion is determined by that shift. In the region of intermediate temperatures T, for each value of the phase shift, one can indicate a temperature Ts > Tc such that at T < Ts the particle moves in one direction, while at T > Ts in the other. [ABSTRACT FROM AUTHOR] more...

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We study dynamic contracting with adverse selection and limited commitment. A firm (the principal) and a worker (the agent) interact for potentially infinitely many periods. The worker is privately informed about his productivity and the firm can only commit to short‐term contracts. The ratchet effect is in place since the firm has the incentive to change the terms of trade and offer more demanding contracts when it learns that the worker is highly productive. As the parties become arbitrarily patient, the equilibrium outcome takes one of two forms. If the prior probability of the worker being productive is low, the firm offers a pooling contract and no information is ever revealed. In contrast, if this prior probability is high, the firm fires the unproductive worker at the beginning of the relationship. [ABSTRACT FROM AUTHOR] more...

In humans, cultural evolutionary processes are capable of shaping our cognition, because the conceptual tools we learn from others enable mental feats which otherwise would be beyond our capabilities. This is possible because human culture supports the intergenerational accumulation of skills and knowledge, such that later generations can benefit from the experience and exploration efforts of their predecessors. However, it remains unclear how exactly human social transmission supports the accumulation of advantageous traits, and why we see little evidence of this in the natural behavior of other species. Thus, it is difficult to know whether the cognitive abilities of other animals might be similarly scaffolded by processes of cultural evolution. In this article, I discuss how experimental studies of cultural evolution have contributed to our understanding of human cumulative culture, as well as some of the limitations of these approaches. I also discuss how similar research designs can be used to evaluate the potential for cumulative culture in other species. Such research may be able to clarify what distinguishes human cumulative culture from related phenomena in nonhumans, shedding light on the issue of whether other species also have the potential to develop cognitive capacities that are outcomes of cultural evolution. Culture drives cognitive evolution by supporting the transmission and intergenerational accumulation of skills and knowledge, based on social learning and teaching: Later generations benefit from what their predecessors acquired. Taking a metaperspective on those experimental studies that explore the mechanisms underlying cultural transmission, Caldwell discusses their potential for generating valuable insights, their possible limitations, and their generalizability to other species. [ABSTRACT FROM AUTHOR] more...

Electrodeposited nanowires are an excellent scenario to study and control magnetic domain wall motion in nanostructures. In particular, the introduction of local changes in composition during the growth procedure has been proven to be very efficient for controlling the magnetization dynamics. In this work, we show the possibility of introducing compositional gradients in FeNi electrodeposited nanowires by gradually changing the Fe/Ni ratio along their axis. These compositional gradients produce an asymmetrical landscape for domain wall motion which is reflected in asymmetrical magnetization processes under an applied magnetic field. By studying nanowires with different compositional gradients we were able to correlate composition and magnetic asymmetry. Our results pave the way towards full control of the movement of domain walls along the nanowires. [ABSTRACT FROM AUTHOR] more...

Inner surface of Nepenthes slippery zone shows anisotropic superhydrophobic wettability. Here, we investigate what factors cause the anisotropy via sliding angle measurement, morphology/structure observation and model analysis. Static contact angle of ultrapure-water droplet exhibits the value of 154.80°–156.83°, and sliding angle towards pitcher bottom and up is 2.82 ± 0.45° and 5.22 ± 0.28°, respectively. The slippery zone under investigation is covered by plenty of lunate cells with both ends bending downward, and a dense layer of wax coverings without directional difference in morphology/structure. Results indicate that the slippery zone has a considerable anisotropy in superhydrophobic wettability that is most likely caused by the lunate cells. A model was proposed to quantitatively analyse how the structure characteristics of lunate cells affect the anisotropic superhydrophobicity, and found that the slope/precipice structure of lunate cells forms a ratchet effect to cause ultrapure-water droplet to roll towards pitcher bottom/up in different order of difficulty. Our investigation firstly reveals the mechanism of anisotropic superhydrophobic wettability of Nepenthes slippery zone, and inspires the bionic design of superhydrophobic surfaces with anisotropic properties. more...

We study the implications of aggregating consumers' purchase histories into scores that proxy for unobserved willingness to pay. A long-lived consumer interacts with a sequence of firms. Each firm relies on the consumer's current score–a linear aggregate of noisy purchase signals—to learn about her preferences and to set prices. If the consumer is strategic, she reduces her demand to manipulate her score, which reduces the average equilibrium price. Firms in turn prefer scores that overweigh past signals relative to applying Bayes' rule with disaggregated data, as this mitigates the ratchet effect and maximizes the firms' ability to price discriminate. Consumers with high average willingness to pay benefit from data collection, because the gains from low average prices dominate the losses from price discrimination. Finally, hidden scores—those only observed by the firms—reduce demand sensitivity, increase average prices, and reduce consumer surplus, sometimes below the naive-consumer level. [ABSTRACT FROM AUTHOR] more...

The symmetry conditions under which the ratchet effect of a Brownian photomotor occurs or does not occur were considered. Using symmetry transformations for which average photomotor velocity is invariant, it was shown that, on substrates with symmetric charge distribution, individual Brownian particles can undergo directed motion only if an antisymmetric charge distribution fluctuates in them. In this case, the ensemble with averaged orientations of particles cannot execute directed motion as a whole and spreads by diffusion. On the other hand, on substrates with antisymmetric charge distribution, both individual Brownian particles and their ensemble with averaged orientations can undergo directed motion only if a symmetric charge distribution fluctuates. If the time dependence of the particle charge distribution is described by a periodic function of time with a universal type of symmetry (which is simultaneously symmetric, antisymmetric, and invariant under a half-period shift with sign reversal), then the ratchet effect cannot occur in the overdamped regime, but it is allowed if the inertia of particles is taken into account and the charge distributions in both the particle and the substrate are neither symmetric nor antisymmetric. [ABSTRACT FROM AUTHOR] more...

In spite of the widespread opinion about the negative effect of chaos on the nature and human life, there exist examples of its constructive role in various processes. Among them, a prominent position is occupied by the processes in which thermal noise causes not only Brownian motion but also drift of nanoparticles as a result of unbiased non-equilibrium perturbations of various nature in systems with broken spatial and/or temporal symmetry. Such processes are relevant to the operation of Brownian motors, or ratchets, actively studied in the past decades. In the present paper, the working principles of systems of this kind are explained based on the author’s approach which unifies the treatment of different ratchet effect manifestations in the models of fluctuating potential, catalytic wheel, and electroconformational coupling. Another manifestation of this effect is provided by the paradoxical games proposed by Parrondo in which chaos appears in random tosses of a die and the ratchet effect arises from a certain alternation of game strategies ensuring an average win. The paper presents the simplest version of Parrondo’s game; it consists in the alternation of two antisymmetric games, with the rules depending on the parity of the capital possessed by the player before the next toss. The dependence of the average win on the number of tosses is calculated by computer simulation and compared with the result of the catalytic wheel model valid in the adiabatic approximation. The theoretical win calculated by this model agrees well with the numerical simulation result for the game concerned. The attractiveness of the treatment of the ratchet effect in terms of game theory stems from the possibility to visualize the theoretical framework and to study the laws of Brownian motor operation by simple modelling methods. [ABSTRACT FROM AUTHOR] more...

The combinatorial clock auction (CCA) has frequently been used in recent spectrum auctions. It combines a dynamic clock phase and a one‐off supplementary round. The winning allocation and the corresponding prices are determined by the Vickrey–Clarke–Groves rules. These rules should encourage truthful bidding, whereas the clock phase is intended to reveal information. We inquire into the role of the clock when bidders have lexicographic preferences for raising rivals' costs. We show that in an efficient equilibrium, the clock cannot fully reveal bidders' types. In the spirit of the ratchet effect, in the supplementary round competitors extract surplus from strong bidders whose type is revealed. We also show that if there is substantial room for information revelation, that is, if the uncertainty about the final allocation is large, all equilibria of the CCA are inefficient. Qualitative features of our equilibria are in line with evidence concerning bidding behavior in some recent CCAs. [ABSTRACT FROM AUTHOR] more...

We use a contract theory/mechanism design framework to analyse the fiscal relations and reforms between the central and local governments in China, which are said to have made great contributions to economic growth since the 'economic reform'. First, we present the mechanism (a fiscal incentive contract model), which has created incentives for the development agent (local government), and clarify theoretically how the concept of bao (contract) works. We then comprehend the concept of bisai (contest) within the framework of the yardstick competition between local governments, and review the mechanism which encourages proper information revelation through intergovernmental comparison and competition. Lastly, we make a theoretical comparative analysis on the fiscal system reform (from the fiscal contracting system to the tax sharing system), from the perspective of how much room was left for the 'ratchet effect' in the dynamic relation between the central and local governments, and how it was solved (or mitigated) in the two fiscal systems. [ABSTRACT FROM AUTHOR] more...

This paper applies the concept of emergency powers to the crisis politics of international organizations (IOs). In the recent past, IOs like the UN Security Council, the WHO, and the EU have reacted to large-scale crises by resorting to assertive governance modes bending the limits of their competence and infringing on the rights of the rule-addressees. In contrast to rational and sociological institutionalist notions of mission creep, this paper submits that this practice constitutes 'authority leaps' which follow a distinct logic of exceptionalism: the expansion of executive discretion in both the horizontal (lowering of checks and balances) and the vertical (reduction of legal protection of subjects) dimension, justified by reference to political necessity. This 'IO exceptionalism', as argued here, represents a class of events which is observable across fundamentally different international institutions and issue areas. It is important not least because emergency politics tend to leave longer-term imprints on a polity's authority structures. This article shows that the emergency powers of IOs have a tendency to normalize and become permanent features of the institution. Thus IO exceptionalism and its ratcheting up represent a mechanism of abrupt but sustainable authority expansion at the level of IOs. [ABSTRACT FROM AUTHOR] more...