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Preferential flow within soil cracks influences land surface hydrological processes, yet direct quantifying preferential flow velocity (PFV) remains challenging. Here, we develop a method for high‐resolution monitoring and quantifying PFV in soil cracks using optical frequency domain reflectometry (OFDR). Building on the flow characteristics of preferential flow, we further establish a quantitative framework that links crack width to PFV through a physically based drag‐partitioning mechanism. Laboratory experiments and field slope monitoring enable continuous and accurate measurement of PFV and reveal a coupled evolution between crack width and PFV during flow flushing. This coupled behavior is interpreted from a dynamical perspective based on redistribution of viscous and form drag. By mechanistically relating PFV to readily measurable crack width, the proposed framework provides a parameterization pathway for improving hydrological models. Incorporating crack‐scale PFV enhances the representation of infiltration and other surface hydrological processes.

Although research has explained how plant roots mechanically stabilize soils, in this article we explore how root systems create networks of preferential flow and thus influence water pressures in soils to trigger landslides. Root systems may alter subsurface flow: Hydrological mechanisms that promote lower pore-water pressures in soils are beneficial to slope stability, whereas those increasing pore pressure are adverse. Preferential flow of water occurs in the following types of root channels: (a) channels formed by dead or decaying roots, (b) channels formed by decayed roots that are newly occupied by living roots, and (c) channels formed around live roots. The architectural analysis of root systems improves our understanding of how roots grow initially, develop, die, and interconnect. Conceptual examples and case studies are presented to illustrate how root architecture and diverse traits (e.g., diameter, length, orientation, topology, sinuosity, decay rate) affect the creation of root channels and thus affect preferential flow.

No generally accepted framework exists for constructing and evaluating measures of corruption. This article shows how the axiomatic approach of the poverty and inequality literature can be applied to the measurement of corruption. A conceptual framework for organizing corruption data is developed, and three aggregate corruption measures consistent with axiomatic requirements are proposed. The article also provides guidelines for empirical applications of corruption measures and discusses data requirements. A brief empirical example illustrates how each of the measures captures a distinct view of corruption that yields a different ranking. To the authors' knowledge, this article provides the first analysis of corruption measurement using an axiomatic framework.

Preferential trade agreements have become common ways to protect or restrict access to national markets in products and services. The United States has signed trade agreements with almost two dozen countries as close as Mexico and Canada and as distant as Morocco and Australia. The European Union has done the same. In addition to addressing economic issues, these agreements also regulate the protection of human rights. InForced to Be Good, Emilie M. Hafner-Burton tells the story of the politics of such agreements and of the ways in which governments pursue market integration policies that advance their own political interests, including human rights. How and why do global norms for social justice become international regulations linked to seemingly unrelated issues, such as trade? Hafner-Burton finds that the process has been unconventional. Efforts by human rights advocates and labor unions to spread human rights ideals, for example, do not explain why American and European governments employ preferential trade agreements to protect human rights. Instead, most of the regulations protecting human rights are codified in global moral principles and laws only because they serve policymakers' interests in accumulating power or resources or solving other problems. Otherwise, demands by moral advocates are tossed aside. And, as Hafner-Burton shows, even the inclusion of human rights protections in trade agreements is no guarantee of real change, because many of the governments that sign on to fair trade regulations oppose such protections and do not intend to force their implementation. Ultimately, Hafner-Burton finds that, despite the difficulty of enforcing good regulations and the less-than-noble motives for including them, trade agreements that include human rights provisions have made a positive difference in the lives of some of the people they are intended-on paper, at least-to protect.

Humans regularly assess the quality of their judgements, which helps them adjust their behaviours. Metacognition is the ability to accurately evaluate one's own judgements, and it is assessed by comparing objective task performance with subjective confidence report in perceptual decisions. However, for preferential decisions, assessing metacognition in preference‐based decisions is difficult because it depends on subjective goals rather than the objective criterion. Here, we develop a new index that integrates choice, reaction time, and confidence report to quantify trial‐by‐trial metacognitive sensitivity in preference judgements. We found that the dorsomedial prefrontal cortex (dmPFC) and the right anterior insular were more activated when participants made bad metacognitive evaluations. Our study suggests a crucial role of the dmPFC‐insula network in representing online metacognitive sensitivity in preferential decisions. We integrated choice valuation, response time, and subjective confidence to probe the quality of confidence in preferential decisions. We found that the anterior insula and dorsal medial prefrontal cortex are involved in encoding the quality of metacognitive deliberation during preference judgements.

Natural aquifers usually exhibit complex physical and chemical heterogeneities, which are key factors complicating kinetic processes, such as contaminant transport and transformation, posing a great challenge in the remediation of contaminated groundwater. Aquifer heterogeneity usually leads to a distinct feature, the so-called “anomalous transport” in groundwater, which deviates from the phenomenon described by the classical advection-dispersion equation (ADE) based on Fick’s Law. Anomalous transport, also known as non-Fickian dispersion or “anomalous dispersion” in a broad sense, can explain the hydrogeological mechanism that leads to the temporally continuous deterioration of water quality and rapid spatial expansion of pollutant plumes. Contaminants enter and then are retained in the low-permeability matrix from the high-permeability zone via molecular diffusion, chemical adsorption, and other mass exchange effects. This process can be reversed when the concentration of pollutants in high-permeability zones is relatively low. The contaminants slowly return to the high-permeability zones through reverse molecular diffusion, resulting in sub-dispersive anomalous transport leading to the chronic gradual deterioration of water quality. Meanwhile, some contaminants are rapidly transported along the interconnected preferential flow paths, resulting in super-dispersive anomalous transport, which leads to the rapid spread of contaminants. Aquifer heterogeneity is also an important factor that constrains the efficacy of groundwater remediation, while the development, application, and evaluation of groundwater remediation technologies are usually based on the Fickian dispersion process predicted by the ADE equation. Comprehensive studies of the impacts of non-Fickian dispersion on contaminant transport and remediation are still needed. This article reviews the non-Fickian dispersion phenomenon caused by the heterogeneity of geological media, summarizes the processes and current understanding of contaminant migration and transformation in highly heterogeneous aquifers, and evaluates mathematical methods describing the main non-Fickian dispersion features. This critical review also discusses the limitations of existing research and outlines potential future research areas to advance the understanding of mechanisms and modeling of non-Fickian dispersion in heterogeneous media.

Purpose There is strong experimental evidence that root systems substantially change the hydraulic properties of soil. However, the mechanisms by which they do this remain largely unknown. In this work, we made the hypothesis that a preferential flow of soil moisture occurs in directions which follow the orientation and distribution of roots within the soil, and that this phenomenon alters soil moisture flow patterns. Methods We modified Richards’ equation to incorporate root-oriented preferential flow of soil moisture. Using the finite element method and Bayesian optimisation, we developed a pipeline to calibrate our model with respect to a given root system. Results When applied to simulated root distributions, our model produced pore-water pressure profiles which agreed with those derived from experimental saturated hydraulic conductivity values of soils vegetated with willow and grass. Agreement improved for simulated root distributions where root segments were oriented in a more realistic way, suggesting that the hydraulic characteristics of vegetated soils are a consequence of root-oriented preferential flow. Conclusion By incorporating root-oriented preferential flow, our model improves the ability to describe and analyse water infiltration through vegetated soil. This could help optimise irrigation, forecast flood events and plan landslide prevention strategies.

In humid hilly regions, macropore preferential flow in soils dominates the distribution of event water, thereby influencing the generation and development of runoff. However, the mechanism of how soil functions on macropore drainage and matrix absorption remains poorly understood due to complex soil water dynamics in a multi‐porosity subsurface network. In this study, based on the source‐responsive method that divides the soil into source‐responsive and diffusive domains, the allocation ratio of infiltrated water in macropores recharging the matrix were derived and it was coupled with PIHM (Penn State Integrated Hydrologic Model) as PIHM‐SRM (PS). By simulating the soil moisture process at profile scale and the runoff process at catchment scale, it was found that the PS overcame the difficulty of most hydrologic models in describing the process of replenishing moisture in dry soil. This leads to more satisfactory performance for flood peaks at the outlet (CCC > 0.84) and soil moisture peaks at three profiles (CCC = 0.97) compared to original PIHM models. Moreover, the separate channel of film flow in the PS further improves the simulation accuracy of peak response speed in subsurface floods under rainstorms (TP > 40 mm). Additionally, sensitivity analysis shows that the storage‐discharge capacity of soil profiles dominates torrential flood forecasting in humid headwaters when considering the influence of macropores. Finally, considering the parameter‐predictive property in the PS, field‐based parameterized strategies are vital for distributed catchment modeling. This will enable the PS to improve flash torrent predictions in headwaters and be applied at catchment scales. Key Points Under the source‐responsive framework, the allocation ratio of infiltrated water was derived and a PIHM‐based model (PS) was developed The PS outperformed the original PIHM models in simulating soil moisture peaks at profiles, and flood peaks and response speed at outlets By introducing simple, physically meaningful macropore parameters, the PS could simulate rapid subsurface stormflow at catchment scales