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Shear wave splitting of teleseismic core phases such as SKS is commonly used to constrain mantle seismic anisotropy, a proxy for convective deformation. In plate boundaries, sharp lateral variations of splitting measurements near transform faults are often linked to deformation within a lithospheric shear zone below, but potential seismic waveform effects from heterogeneous structure on small scales may influence the interpretation. Here, we explore possible finite frequency effects on shear wave splitting near fault zones in a fully three‐dimensional anisotropic setting. We find that shear zones wider than 80 km, a scale set by the Fresnel zone, can be clearly detected, but narrower zones are less distinguishable. Near the edge of the shear zone, the combined effect of anisotropy and scattering generates false splitting measurements with large delay times and fast axis orientation approaching the back‐azimuth, a bias which can only be identified when records from different back‐azimuths are analyzed together. This substantiates that back‐azimuthal variations of splitting can arise not just from vertical layering but also lateral changes of anisotropic media. We also test the effects of shear zone edge geometry, epicentral distance, filtering frequency, crustal thickness, and sediment cover. Our study delineates the ability of shear wave splitting to resolve and investigate fault zones, and emphasizes the importance of good azimuthal coverage to correctly interpret observed anisotropy. Based on revisiting previous shear wave splitting and lithospheric deformation studies, we infer that many crustal fault zones are underlain by lithospheric shear zones at least 20 km wide. 

Abstract Glucocorticoids (corticosterone/cortisol; cort) are frequently used in conservation as biomarkers of disturbance in wild populations. However, the context‐dependent nature of cort means that it may not always accurately reflect disturbance. For example, there is growing evidence that wildlife populations can evolve or acclimate to human‐induced environmental change (i.e. contaminants) by expressing higher levels of tolerance. Mechanisms that allow for populations to achieve higher contaminant tolerance can be related to cort and thereby impact the reliability of cort as an indicator of disturbance. This study asks: (1) do wildlife populations that differ in tolerance to contaminants differentially express baseline and stress‐induced cort and (2) is cort a viable indicator of disturbance across populations that differ in tolerance to contaminants? Toward this goal, we identified three wood frogRana sylvaticapopulations with relatively high NaCl tolerance and three populations with relatively low NaCl tolerance. Tadpoles from these populations were reared to metamorphosis in either an environmentally relevant concentration of NaCl (0.5 g L⁻¹NaCl) or a control (0 g L⁻¹NaCl). At metamorphosis we used a non‐invasive waterborne assay to measure baseline and stress‐induced cort release rates and measured fitness‐related metrics. We found that contaminant tolerance influences cort levels. More tolerant populations had lower baseline cort and higher fitness compared to less tolerant populations. However, despite variation in cort across populations with different levels of tolerance, cort still represents a viable indicator of condition as our results show a consistent negative relationship between cort and fitness. Lastly, we found that levels of cort were consistent regardless of whether amphibians were reared in NaCl contaminated or non‐contaminated environments. Overall, we emphasize the importance of recognizing population‐level variation in cort due to contaminant tolerance when using cort as a biomarker for conservation purposes. 

Abstract This study presents an improved approach to common‐conversion point stacking of converted body waves that incorporates scattering kernels, accurate and efficient measurement of stack uncertainties, and an alternative method for estimating free surface seismic velocities. To better separate waveforms into thePandSVcomponents to calculate receiver functions, we developed an alternative method to measure near‐surface compressional and shear wave velocities from particle motions. To more accurately reflect converted phase scattering kernels in the common‐conversion point stack, we defined new weighting functions to project receiver function amplitudes only to locations where sensitivities to horizontal discontinuities are high. To better quantify stack uncertainties, we derived an expression for the standard deviation of the stack amplitude that is more efficient than bootstrapping and can be used for any problem requiring the standard deviation of a weighted average. We tested these improved methods onSpphase data from the Anatolian region, using multiple band‐pass filters to image velocity gradients of varying depth extents. Common conversion point stacks of 23,787Spreceiver functions demonstrate that the new weighting functions produce clearer and more continuous mantle phases, compared to previous approaches. The stacks reveal a positive velocity gradient at 80–150 km depth that is consistent with the base of an asthenospheric low‐velocity layer. This feature is particularly strong in stacks of longer period data, indicating it represents a gradual velocity gradient. At shorter periods, a lithosphere‐asthenosphere boundary phase is observed at 60–90 km depth, marking the top of the low‐velocity layer. 

Abstract The superτ-charm facility (STCF) is an electron–positron collider proposed by the Chinese particle physics community. It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5 × 10³⁵cm⁻²·s⁻¹or higher. The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory — the BEPCII, providing a unique platform for exploring the asymmetry of matter-antimatter (charge-parity violation), in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions, as well as searching for exotic hadrons and physics beyond the Standard Model. The STCF project in China is under development with an extensive R&D program. This document presents the physics opportunities at the STCF, describes conceptual designs of the STCF detector system, and discusses future plans for detector R&D and physics case studies.