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Identifying the origins of storm fluvial particulate organic carbon (POC) provides information about the hydrological connectivity within the river corridor and the roles of the land-stream interface in the carbon cycle. However, current understanding of storm-induced POC source dynamics is constrained by observations limited in space and time. This study presents a unique approach integrating higher spatial and temporal resolution sampling with a multi-biomarker analysis to better understand POC source dynamics across scales. Storm POC samples were collected at ~2 h intervals at three locations along the flow trajectory of an agricultural stream during six storm events with varied storm characteristics and seasonality, and characterized for their concentrations, C and N contents, stable C isotopes, and biomarker contents. Our results showed a source transition from in-stream algal production during early storm stages to surface soils with vascular plant signatures during peak precipitation and discharge across events and stations. Biomarkers further resolved the terrestrial signature into one likely from bank vegetation and another from row crop soils. This additional separation appeared conditionally, with the magnitude and sequence influenced by environmental factors such as storm trajectory, antecedent conditions, and management/vegetation cover. Source transitions were less distinctive in the lower reaches due to the greater integration of inputs, although one storm with localized precipitation showed the opposite pattern. Both scenarios align with the expected lower hydrological connectivity downstream. With the employed approach, the evolution of the storm pulse POC as it responds to river corridor processes could be visualized both temporally and spatially. 

Understanding the microscopic origin of the superior electromechanical response in relaxor ferroelectrics requires knowledge not only of the atomic-scale formation of polar nanodomains (PNDs) but also the rules governing the arrangements and stimulated response of PNDs over longer distances. Using x-ray coherent nanodiffraction, we show the staggered self-assembly of PNDs into unidirectional mesostructures that we refer to as polar laminates in the relaxor ferroelectric 0.68PbMg_1/3Nb_2/3O₃-0.32PbTiO₃(PMN-0.32PT). We reveal the highly heterogeneous electric-field–driven responses of intra- and interlaminate PNDs and establish their correlation with the local strain and the nature of the PND walls. Our observations highlight the critical role of hierarchical lattice organizations on macroscopic material properties and provide guiding principles for the understanding and design of relaxors and a wide range of quantum and functional materials. 

KTaO₃heterostructures have recently attracted attention as model systems to study the interplay of quantum paraelectricity, spin-orbit coupling, and superconductivity. However, the high and low vapor pressures of potassium and tantalum present processing challenges to creating heterostructure interfaces clean enough to reveal the intrinsic quantum properties. Here, we report superconducting heterostructures based on high-quality epitaxial (111) KTaO₃thin films using an adsorption-controlled hybrid PLD to overcome the vapor pressure mismatch. Electrical and structural characterizations reveal that the higher-quality heterostructure interface between amorphous LaAlO₃and KTaO₃thin films supports a two-dimensional electron gas with substantially higher electron mobility, superconducting transition temperature, and critical current density than that in bulk single-crystal KTaO₃-based heterostructures. Our hybrid approach may enable epitaxial growth of other alkali metal–based oxides that lie beyond the capabilities of conventional methods. 

Further miniaturization of electronic devices necessitates the introduction of new materials, including piezoelectric thin films, that exhibit electromechanical functionalities without significant degradation in response due to substrate-induced clamping. To identify material systems with superior piezoelectric properties as thin films, simplified and quantitative electromechanical characterization techniques are required. Here, single-beam, laser Doppler vibrometry is used to detect ac electric-field-induced surface displacement in the frequency range 1–100 kHz with low error (around 6% at 10 kHz) and resolution of 0.0003 nm. The technique is used to quantify both electrostriction and piezoelectric responses (surface displacement values <0.05 nm) of various thin films. Requirements for sample geometry and device structures are established and measurement accuracy and resolution are validated against measurements from the literature via synchrotron-based diffraction measurements. A general methodology to measure and extract the piezoelectric coefficients for thin-film samples using finite-element modeling is presented and applied to determine the d33 coefficient and visualize the response in substrate-clamped 50–400-nm-thick PbZr0.52Ti0.48O3 films, especially as compared to bulk versions with the same sample geometry. 

How and when do opportunities for political participation through courts change under authoritarianism? Although China is better known for tight political control than for political expression, the 2008 Open Government Information (OGI) regulation ushered in a surge of political-legal activism. We draw on an original dataset of 57,095 OGI lawsuits, supplemented by interview data and government documents, to show how a feedback loop between judges and court users shaped possibilities for political activism and complaint between 2008 and 2019. Existing work suggests that authoritarian leaders crack down on legal action when they feel politically threatened. In contrast, we find that courts minted, defined, and popularized new legal labels to cut off access to justice for the super-active litigants whose lawsuits had come to dominate the OGI docket. This study underscores the power of procedural rules and frontline judges in shaping possibilities for political participation under authoritarianism.