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Subducting the buoyant crustal material of an aseismic oceanic ridge has been regarded as a dominant contributor to flat slab subduction. However, normal‐dip subduction is also observed in some cases where ridges are subducting. In this study, we compare the subduction of two ridges on the Nazca Plate: Nazca Ridge (flat slab) and Iquique Ridge (normal‐dip slab). Anisotropy determined by shear wave splitting observation suggests that the low‐velocity anomalies found beneath the ridges are mapping anisotropic structure into isotropic velocities. After a tomographic inversion incorporating anisotropy models for both ridges, we find that the low‐velocity anomalies found beneath the Nazca Ridge are not anisotropic and therefore likely represent warm mantle, and those beneath the Iquique Ridge are caused by anisotropy. We conclude that subslab mantle buoyancy has a larger impact on the subduction angle than the crustal material of the ridge. Plain Language Summary: Understanding the subduction process and how the mantle flows is pivotal in understanding the planetary evolution of Earth. Yet, several subduction characteristics remain unsolved, and the angle of plate subduction, which is often categorized into <30° (shallow), ∼30–35° (normal), >35° (steep), is one of those. Subduction of an oceanic ridge on a plate has been proposed as a cause of a shallow subduction angle since the thick crust of the ridge is less dense than the surrounding mantle. However, normal angles have been observed in some cases where oceanic ridges are subducting. In this study, we compare the Nazca Ridge and the Iquique Ridge, on the Nazca Plate subducting beneath South America. The subduction angles of the Nazca and Iquique Ridges are shallow and normal, respectively. When we incorporate directional variations in seismic wave velocities, which are produced by mantle flow, in seismic tomographic imaging, we find that the subducting oceanic ridge may not be a primary factor producing shallow angle subduction. Instead, the warm mantle beneath the Nazca Ridge may provide the buoyancy to support the Nazca Plate. Comparably, since the mantle beneath the Iquique Ridge is not warm, the subduction angle would stay normal. Key Points: Despite having different subduction angles, subslab low‐velocity anomalies are found beneath both Nazca Ridge and Iquique RidgeWe introduced hypothetical seismic anisotropy in tomographic inversion to explore the origin of the subslab low‐velocity anomaliesThe low‐velocity anomalies beneath the Nazca Ridge and Iquique Ridge may come from buoyant warm mantle and anisotropy, respectively [ABSTRACT FROM AUTHOR]

The weak slab interface controls long-term subduction dynamics. A weak hydrous layer at the slab interface promotes mechanical decoupling between the forearc mantle and the subducting slab and converts a hot forearc mantle to a cold mantle. Often referred to as a cold nose, the cold forearc mantle, plays a key role in the transition from subduction infancy to mature subduction. This study was the first to numerically demonstrate the self-consistent formation of a weak hydrous layer with permeability anisotropy based on the Southwest Japan subduction zone case, where transition-related geological features were present. Our models showed that mechanical decoupling by spontaneous downdip growth of the weak hydrous layer created a cold nose by converting a hot forearc mantle to a cold mantle. The emergence of a cold nose explained the migration of the forearc-to-arc volcanic front, expressed as the formation of mid-Miocene forearc high-magnesium andesite and Quaternary arc adakite. Furthermore, the weak hydrous layer providing a pathway for free-water transport toward the mantle wedge tip elucidates slab/mantle-derived geochemical components in deep groundwater as well as large S-wave delay times and non-volcanic seismic tremors in the forearc. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to investigate the effectiveness and understand the process of a nurse‐led social media intervention for health behavior and glucose control for diabetes self‐management among patients with type 2 diabetes mellitus. Design This study had an explanatory sequential mixed methods design, with a randomized controlled trial and qualitative interviews. Methods: A total of 89 patients diagnosed with type 2 diabetes mellitus were randomly assigned to an intervention or a control group. Patients in the intervention group were invited to join the closed nurse‐led social media platform that included diabetes information, action planning, unmoderated chat, and questions and answers. The outcomes of diabetes self‐care behavior, hemoglobin A1c (HbA1c) percentage, fasting blood sugar level (FBS), systolic and diastolic blood pressure, and triglyceride (TG) and total cholesterol levels were measured at baseline, 3 months, and 6 months. A linear mixed model was used to analyze the effectiveness of the intervention over time. Qualitative data were collected from interviews with seven patients engaged in the intervention and analyzed using qualitative content analysis. Findings After 6 months, insulin users who were provided with the social media intervention had significantly lower FBS and TG levels than those with usual care (135.80 ± 12.37 vs. 175.82 ± 15.34 mg/dL, p = 0.049; 206.85 ± 38.26 vs. 387.50 ± 56.19 mg/dL, p = 0.013; respectively). Although a similar rate of decrease in the HbA1c level over time was observed among insulin and noninsulin users after the social media intervention, this decrease was significantly greater among noninsulin users at 3 and 6 months compared with the control group (6.38 ± 0.34 vs. 7.25 ± 0.24, p = 0.040; 6.31 ± 0.37 vs. 7.28 ± 0.26, p = 0.036; respectively). Interview with seven patients who engaged in the intervention revealed that their engagement in the intervention was primarily determined by their acceptance of the role of managing their diabetes. Being engaged in the intervention, patients benefited from information sharing and interactive support to motivate their self‐care, nurses' professional advice to modify their behaviors, and action planning to make progress toward behavioral change. Conclusions: The positive outcomes of the nurse‐led social media intervention indicate that the social media platform is an effective strategy to implement diabetes self‐management in clinical nursing practice. Clinical Relevance: The social media intervention would be successfully implemented by nurses to facilitate patients accepting their role in diabetes management and employing key services for diabetes information, support, professional advice, and action planning. [ABSTRACT FROM AUTHOR]

Jeju Island is an intraplate volcanic island with enigmatic origins, located on the continental shelf south of the Korean Peninsula. A dense temporary seismic array, operated on Jeju Island from 2013 to 2015, revealed several important constraints on the magma plumbing system of Jeju Island. In this study, we determined the deep crustal seismic structure beneath Jeju Island from the teleseismic P -to- S converted phases (receiver functions) recorded from 20 temporary and three permanent stations. We removed the contribution of near-surface reverberations in the resulting receiver functions by applying a resonance removal filter. We estimated crustal P -to- S velocity ratio (VP / VS) and discontinuity depth to provide teleseismic constraints on the composition and structure. We observed two major seismic discontinuities, which are the upper boundaries of a mid-to-lower crustal low-velocity zone (LVZ) and the Moho transition zone. The depth to the upper boundary of the LVZ is deep in the west and southeast (24–30 km) and shallow in the northeast (8–11 km). The LVZ can be interpreted as an extensively distributed residual magma plumbing system, with magma batches stalled at various levels and at various degrees of crystallization, consistent with the chemical diversity of Jeju magmas. The seismic characteristics of the Moho transition zone vary greatly among regions. The top interface of the Moho transition zone is at a wide range of depth (26–40 km), and is shallow at 26–29 km depths beneath central Jeju, suggesting a complex Moho topography. The presence of mafic cumulates and partially molten mushes may contribute to the observed shallow seismic discontinuity at a depth of 26–29 km. The lack of obvious crustal thickening below the shield volcano, Mt Halla, may be associated with mantle upwelling or presence of mafic underplating and cumulates below Jeju. Spatial variations of crustal VP / VS represent highly heterogeneous crustal composition, resulting from magma differentiation during the evolution of the island. [ABSTRACT FROM AUTHOR]

This paper aims to improve the robustness of interpretation in the S receiver function (SRF), a technique commonly used to retrieve forward scattering of S -to- P converted waves (Sdp) originated from the lithosphere–asthenosphere system (LAS) beneath the stations. Although the SRF does not suffer interferences from backward scattering waves such as the first multiples from the Moho, one major drawback in the method is that Sdp phases can interfere with P coda waves and it is conceivable that these signal-generated noise may be misinterpreted as Sdp phase from the LAS beneath seismic stations. Through systematic analysis of full-waveform synthetics and SRFs from catalogued source parameters, we find that the strong P coda waves before the S wave in the longitudinal-component waveforms result in unwanted signal-generated noise before the S wave in the synthetic SRFs. If the mean amplitude of SRFs after the S wave is large, dubious signal-generated noise before the S arrival are strong as well. In this study, we honor the level of these unwanted signal-generated noise and devise data-oriented screening criteria to minimize the interference between P coda waves and genuine S -to- P converted waves. The first criterion is LQR, a direct measure of the amplitude ratio between longitudinal P coda waves and radial S wave in the waveform data. The second criterion is AMP, the amplitude of SRFs after the S arrival. We illustrate that these criteria effectively measure the energy level of mantle waves such as the SP wave. With synthetics and real data, we demonstrate the effectiveness of LQR and AMP criteria in minimizing these unwanted signal-generated noise in the stacked SRFs down to 1–2 per cent, improving detection threshold and interpretation of Sdp phases from seismic discontinuities in the LAS. [ABSTRACT FROM AUTHOR]

Abstract Seismic velocity and anisotropy are mainly controlled by the elastic components of rock microstructure. Here we present a MATLAB program, GassDem (Gassmann Differential effective medium), for modeling anisotropic seismic properties from rock microstructure using differential effective medium (DEM) theory and Gassmann's (1951) poroelastic relationship. Modeling provides a method to overcome the limitations of laboratory measurements, which are unable to reach realistic temperature and pressure conditions. DEM models a two-phase composite that consists of a background medium and inclusions. Components of the rock microstructure, such as porosity, crack geometry, and fluid type in the cracks, are considered to be inclusion properties in DEM theory. Gassmann's poroelastic relationship is used to calculate the elastic stiffness for fluid-saturated rocks. In the formulation of the DEM model, we achieve high numerical efficiency, particularly for inclusions with large aspect ratios, by taking the Fourier transform of the tensor Green's function and using the symmetry of the tri-axial ellipsoid to reduce the amount of integration. We provide examples of DEM modeling and a description for users to replicate the examples using the GassDem graphical user interface, or using a MATLAB script. Highlights • MATLAB program for DEM scheme and Gassmann's poroelastic relationship. • Modelling of elastic properties reflecting the microstructure of rocks. • Calculation of the tensor Green's function using Fourier integrals. • Kelvin tensor to preserve elastic energy density with the advantages in tensor algebra. • High numerical efficiency, particularly for inclusions with large aspect ratios. [ABSTRACT FROM AUTHOR]

Abstract V-doped semi-insulating (VDSI) SiC crystal is a promising substrate for high-frequency electronic devices achieved using GaN epitaxial films. However, V doping in a SiC crystal is difficult to control owing to the different sublimation temperatures of VC and SiC. The amount of V changes depending on the growth sequence, which has been a significant concern in VDSI SiC substrates in terms of wafer reliability. In this study, therefore, we aimed to synthesize a single source by vaporizing Si, C, and V under the same conditions to improve the doping issue in VDSI SiC. We synthesized V-doped SiC powder as the starting material for VDSI SiC substrate based on thermodynamic modeling, and the synthesized powder was used to grow a VDSI SiC crystal via physical vapor transport. Finally, considering the homogeneous V concentration in the grown crystal, the synthesized V-doped SiC was observed to be effective to grow VDSI SiC independent of the growth sequence. [ABSTRACT FROM AUTHOR]

We define subducting plate geometries in the Nazca subduction zone by (re)locating intra-slab earthquakes in southern Peru (14–18°S) and using previously published converted phase analysis results to clarify the slab geometry and inferred relationships to the seismicity. We also provide both P - and S -wave velocity models of the subducting Nazca Plate and mantle layer above the slab using double-difference tomography to understand upper-plate volcanism and subduction zone process. The double-difference constraints for determining the hypocenters and velocity model ensure high accuracy of the relative location of earthquakes with respect to velocity structure. The relocated seismicity shows a smooth contortion in the slab-dip transition zone for ∼400 km between the shallow (30°)-to-flat dipping interface to the northwest and the 30°-dipping interface to the southeast. We find a significant slab-dip difference (up to 10°) between our results and previous slab models along the profile region sampling the horizontal slab at a depth of ∼85–95 km. Robust features in both P - and S -wave tomography inversions are both arc-normal and along-arc velocity variations. In the arc-normal direction, all profile results show that the slab velocities beneath the forearc (down to a depth of ∼100 km) transition to higher velocities beneath the backarc (at ∼100–140 km depth). In the along-arc direction, velocities of the subducting flat slab are shown to be depressed compared to those of the normal-dip slab. In addition, high shear-wave velocities and low Vp / Vs are detected in the mantle layer above the flat slab, indicating its cold and dry environment. Such differences in the velocity structures for the slab and mantle wedge between the two regions may indicate different hydration states, which greatly affects the upper-plate structure of southern Peru. [ABSTRACT FROM AUTHOR]

In this study, by combining photopolymerization and particle leaching technique, in situ formation of porous hydrogel with pore interconnectivity was demonstrated in vivo upon subcutaneous injection into the back of mice as well as in vitro . A precursor solution containing thiolated heparin, PEG-diacrylate (PEG-DA), and gelatin microparticles (GMPs) as a fast dissolving porogen were photopolymerized by visible-light-initiated thiol-ene reaction with eosin Y (EY) as a photo initiator and triethanolamine (TEOA) as a co-initiator. Formation of porous structure of the hydrogel after subsequent leaching of GMPs was confirmed in an animal model as well as in a physiological environment. The physical characteristics of the hydrogel were analyzed, and the acute in vivo biocompatibility of this system was characterized. [ABSTRACT FROM AUTHOR]

We provide teleseismic constraints on the continental collision zone along the SW-NE profile from the Tibetan Plateau to the Alxa block, traversing Lenglong Ling, a topographic boundary of the northeastern Tibetan Plateau. Our seismic profile crosses the Qilian Shan thrust belt, a zone of intense earthquake activity that includes a pair of M W 5.9 earthquakes (in 1986 and 2016) with a 30-year time interval occurring at the city of Menyuan near Lenglong Ling. A high degree of similarity between the two waveforms and their similar hypocenters indicate that the two events are repeating earthquakes. Both P - and S -wave receiver functions show contrasting lithospheric structure and crustal seismic properties across the repeating earthquake region, suggesting that Lenglong Ling can be the crustal boundary between the Tibetan Plateau and the Alxa block. High-frequency P receiver functions clearly show a SW-dipping underthrusted upper crust beneath the foreland of the Qilian Shan thrust belt. A strong low-velocity feature above the intracrustal underthrust beneath southwest Lenglong Ling indicates a mechanically weak zone developed coeval with the main compressional deformation during the last major tectonic event. Our observed, localized upper-crustal deformation beneath Lenglong Ling can be direct evidence of the lateral growth of the northeastern Tibetan Plateau, and can control the seismicity of the Qilian Shan thrust belt, including the Menyuan repeating earthquakes. [ABSTRACT FROM AUTHOR]

Two earthquakes ( M 5.1 and 5.8) ruptured branches of the Yangsan Fault System in Gyeongju, S. Korea on September 12, 2016. After the M 5.8 earthquake, aftershock earthquakes continued to occur, including two notable earthquakes ( M 4.3 and 4.5) on September 12 and 19, 2016. This paper details the early reports of the Yangsan Fault System in the Gyeongsang Basin from various geological and geophysical/seismological perspectives. Based on a review and an initial seismological analysis of the results of the three earthquakes ( M 5.1, 5.8, and 4.5), we present and discuss the following topics: (1) the tectonic setting and the geophysical/seismic structure of the Yangsan Fault System, (2) historical seismicity and inferred seismic hazard from historical (literature) data, and (3) source mechanisms of the three earthquakes. In the end, we highlight some of the outstanding issues with regard to earthquakes and future research topics. [ABSTRACT FROM AUTHOR]

Monolayer transition-metal dichalcogenides (TMDCs) have recently emerged as promising candidates for advanced photonic and valleytronic applications due to their unique optoelectronic properties. However, the low luminescence efficiency of monolayer TMDCs has significantly hampered their use in these fields. Here it is reported that the photoluminescence efficiency of monolayer WS2 can be remarkably enhanced up to fourfold through the fluorination, surpassing the reported performance of molecular and/or electrical doping methods. Its degree is easily controlled by changing the fluorine plasma duration time and can also be reversibly tuned via additional hydrogen plasma treatment, allowing for its versatile tailoring for interfacial band alignment and customized engineering. The striking photoluminescence improvement occurs via a substantial transition of trions to excitons as a result of the strong electron affinity of fluorine dopants, and the fluorination enables unprecedented detection of n-type NH3 gas in WS2 due to changed excitonic dynamics showing excellent sensitivity (at least down to 1.25 ppm). This work provides valuable strategies and insights into exciton physics in monolayer TMDCs, opening up avenues toward highly-efficient 2D light emitters, photovoltaics, nanosensors, and optical interconnects. [ABSTRACT FROM AUTHOR]

Background The aim of this study was to determine whether implantable collamer lens (ICL) implantation to correct myopia is an effective and safe surgical option even after long-term follow up. Design A retrospective observational study was carried out. Participants A total of 281 eyes of 145 myopic patients were included in the study. Methods Patients underwent ICL implantation and had the follow-up period of at least 5 years (87 ± 18.9 months). Main Outcome Measures Outcome measures included uncorrected and corrected distance visual acuities, refraction for the evaluation of efficacy, safety, stability and predictability, ICL vault and adverse events. Results The final mean logMAR uncorrected and corrected distance visual acuities were 0.02 ± 0.19 and −0.12 ± 0.13, respectively. The mean efficacy and safety indices were 1.04 ± 0.32 and 1.20 ± 0.26. The mean spherical equivalent decreased from −8.74 ± 2.27 diopter (D) to −0.58 ± 0.72 D, and there was high predictability with 69.8% and 87.2% having a postoperative refraction within 0.5 D and 1.0 D, respectively. The mean postoperative vault was changed from 2.53 ± 0.6 to 2.00 ± 0.7. Six (2.1%) eyes developed cataract, and the mean endothelial cell loss was 7.8 ± 8.3%. Increased intraocular pressure was found in two (0.7%) eyes that required the exchange of lenses with different sizes. Conclusions Implantable collamer lens implantation to correct myopia was an effective and safe surgery with high predictability and stability during long-term follow up. Slight myopic shift and cataract formation related with change in vault should be further evaluated. [ABSTRACT FROM AUTHOR]

More than a decade after the discovery of deep episodic slow slip and tremor, or slow earthquakes, at subduction zones, much research has been carried out to investigate the structural and seismic properties of the environment in which they occur. Slow earthquakes generally occur on the megathrust fault some distance downdip of the great earthquake seismogenic zone in the vicinity of the mantle wedge corner, where three major structural elements are in contact: the subducting oceanic crust, the overriding forearc crust and the continental mantle. In this region, thermo-petrological models predict significant fluid production from the dehydrating oceanic crust and mantle due to prograde metamorphic reactions, and their consumption by hydrating the mantle wedge. These fluids are expected to affect the dynamic stability of the megathrust fault and enable slow slip by increasing pore-fluid pressure and/or reducing friction in fault gouges. Resolving the fine-scale structure of the deep megathrust fault and the in situ distribution of fluids where slow earthquakes occur is challenging, and most advances have been made using teleseismic scattering techniques (e.g., receiver functions). In this paper we review the teleseismic structure of six well-studied subduction zones (three hot, i.e., Cascadia, southwest Japan, central Mexico, and three cool, i.e., Costa Rica, Alaska, and Hikurangi) that exhibit slow earthquake processes and discuss the evidence of structural and geological controls on the slow earthquake behavior. We conclude that changes in the mechanical properties of geological materials downdip of the seismogenic zone play a dominant role in controlling slow earthquake behavior, and that near-lithostatic pore-fluid pressures near the megathrust fault may be a necessary but insufficient condition for their occurrence. [ABSTRACT FROM AUTHOR]

We review geophysical and geochemical properties in the vicinity of the stagnant Pacific slab beneath northeast China, Korea and Japan to understand the origin and current state of intraplate volcanism in East Asia. East Asia has been susceptible to intensive volcanism since the Cretaceous. In particular, during the Cenozoic, Jeju Island, Korea is the most significant volcanic construct in East Asia. The generation of adakites and A-type granitoids littered throughout East Asia during the Cretaceous has been previously explained by the subduction of the Izanagi–Pacific ridge system. However, a recently revised plate reconstruction model does not comprise such a tectonic episode and consequently fails to explain adakites in arc magmatism during the Cretaceous. Thus, we propose an alternative hypothesis: temporal plume–slab interaction on the source of East Asian magmatism in order to trigger the adakites in arc magmatism without ridge subduction. In addition, we provide an overview on the tectonics and volcanism of Jeju Island during the Cenozoic in the context of the lithospheric structure from seismological constraints and recent geochemical results. The main scientific aims are to understand the consequences of mantle mixing in response to long-term subduction and subsequent changes on the stress state to determine the distribution of chemical heterogeneities, and thus define the origin and development of intraplate volcanism in East Asia. Although geophysical and geochemical data for Jeju Island are not sufficient at present, we strongly state that Jeju Island and the surrounding regions hold a key to unraveling the source of intraplate magmatism since the Cretaceous. [ABSTRACT FROM AUTHOR]

The horizontal Nazca slab, extending over a distance of ∼800 km along the trench is one of enigmatic features in Peruvian subduction zone. Increased buoyancy of the oceanic lithosphere alone due to the subduction of Nazca Ridge is insufficient to fully explain such a lengthy segment. We use data from the recent seismic experiment in southern Peru to find that the subduction-related hydration plays a major role in controlling shear wave velocities within the upper part of the oceanic crust and overlying materials. We observe substantial velocity reductions of ∼20–40% near the top plate interface along- and perpendicular-to the trench from ∼40–120 km depths. In particular, significant shear wave velocity reductions and subsequently higher P-to-S velocity ratio (exceeding 2.0) at the flat slab region suggest that the seismically probed layer is fluid-rich and mechanically weak. The dominant source of fluid comes from metasediments and subducted crust (Nazca Ridge). Long-term supply of fluid from the southward migrating Nazca Ridge provides additional buoyancy of the subducting oceanic lithosphere and also lowers the viscosity of the overlying mantle wedge to drive and sustain the flat plate segment of ∼800 km along the trench. Also, by comparing calculated seismic velocities with experimentally derived mineral physics data, we additionally provide mechanical constraints on the possible changes in frictional behavior across the subduction zone plate interface. Observed low seismic velocities in the seismogenic zone suggest a presence of low strength materials that may be explained by overpressured pore fluids (i.e., accreted sediment included in the subduction channel). [ABSTRACT FROM AUTHOR]

A p H-responsive nanofibrous mesh was prepared for the controlled release of antibiotics in response to p H changes. Eudragit EPO ( EPO) and Eudragit L100 ( L100) were injected through inner and outer needle and simultaneously electrospun through coaxial nozzles composed of inner and outer needles. Various amounts of EPO and L100 were coejected with tetracycline through the needle and simultaneously electrospun to the fibrous meshes. The mass erosion rates of the meshes at p H 6.0 gradually decreased as the amounts of EPO increased, whereas those at p H 2.0 showed negligible differences; these differences were confirmed by scanning electron microscopy and monitoring the dry weight changes. At p H 6.0, the fibrous structures of the meshes rapidly disappeared compared to those under acidic conditions because Eudragit L100 is localized to the shell of the nanofiber during the electrospinning process. Both the p H changes and the blend ratio of the two polymers significantly affected the tetracycline release; tetracycline was rapidly released from the meshes at p H 6.0, whereas the release rates were attenuated at p H 2.0. Tetracycline was released faster from the mesh at higher blend ratios of EPO for both p H values. The electrostatic interaction between EPO and L100 is expected to yield different release profiles of tetracycline. Consequently, higher amounts of encapsulated drugs were released from the mesh at neutral pH and successfully inhibited bacterial growth. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:2611-2618, 2015 [ABSTRACT FROM AUTHOR]

Abstract: Geophysical evidence shows the presence of low-seismic velocity material at the surface of slabs in subduction zones. In the central Mexican subduction zone this appears as a thin (∼4 km) low-velocity zone that absorbs nearly all of the strain. The P-to-S velocity ratio as a function of S wave velocity distinguishes among the various candidate hydrous (low-strength) minerals; the thin layer in the flat-slab region is most consistent with a layer showing enrichment in talc overlying normal MORB-like gabbro. Based on available thermodynamic data for equilibria for talc, its generation at the trench is nearly impossible, and hence we propose it originates from the mantle wedge during the slab flattening process coupled with trench rollback. The evolution of this low-strength zone has important implications for the dynamics of the slab-flattening process as well as the geochemistry of the mantle wedge and arc in central Mexico. [Copyright &y& Elsevier]

Abstract: Teleseismic converted phases are used to probe the composition of the downgoing oceanic crust as a function of depth along the Cocos slab in central and southern Mexico. Previously, modeling of the receiver function (RF) conversion amplitude of the flat Cocos slab beneath central Mexico at 45km depth revealed a thin low-velocity upper oceanic crust of a thickness of 4±1km, which has much lower seismic velocities ( reduction in shear wave velocities) than (normal) lower crust. High Vp/Vs ratio () also suggested a large concentration of hydrous minerals such as talc in combination of high pore-fluid pressure in the horizontal segment. We extend this previous effort to examine seismic properties of both the steeply subducting Cocos oceanic crust beneath the Trans-Mexican Volcanic Belt (TMVB) in central Mexico and the shallowly dipping crust beneath southern Mexico. Inverted seismic velocities using the converted amplitudes at the top and bottom of the dipping oceanic crust are compared with experimentally constrained seismic velocities of candidate mineral phases in a range of likely pressures and temperatures. The composition of the oceanic crust downdip in the steep part of slab beneath the TMVB includes the minerals such as lawsonite and zoisite at 60–100km depth, and the eclogitization occurs around 100km depth. This is related to arc volcanism in the TMVB directly above the slab as well as the slab rollback. In contrast, the dominant mineral phase in the upper oceanic crust of southern Mexico beneath the Isthmus of Tehauntepec is amphibole on top of unaltered gabbroic oceanic crust. The difference in mineral assemblages of the subducted oceanic crust may help explain the difference in slab geometries between central and southern Mexico. [Copyright &y& Elsevier]

As the mantle plume rises from the deep mantle and reaches the base of a tectonic plate, it changes its traveling direction from vertical to horizontal. The horizontal spread of plume material is often radially asymmetric. An example is a plume found below the Canary Hotspot. Previous studies have suggested that the channeling of the Canary Plume toward the westernmost Mediterranean (Alboran Sea) and consequent lithospheric delamination may have contributed to the low‐velocity anomalies found beneath the Moroccan Atlas Mountains. Regional upwelling and edge‐driven convection have been proposed as other candidates to explain the origin of the low‐velocity anomalies. In this study, we incorporated anisotropy as an a priori constraint in teleseismic P‐wave travel‐time tomography as mantle flow can develop seismic anisotropy. We inverted a new set of travel‐time delays by removing the hypothetical anisotropy‐imposed travel‐time delays from the observations. Our improved results are more consistent with the hypothesis that the low‐velocity anomalies come from the mantle material of the Canary Plume. Plain Language Summary: The propagation velocity of seismic waves is sensitive to the temperature. Low seismic velocities in the mantle found from seismic tomography, a technique used to image the velocity structure of the inner Earth with seismic waves, are commonly interpreted as high‐temperature, hydrous regions, the presence of partial melting, changes in the compositional chemistry, and grain sizes of mantle minerals. Thus, seismic tomography has been the primary tool for revealing mantle structures, such as hot plumes rooted in the deep mantle that play significant roles in mantle dynamics. Previous studies have shown that rising plume material can drag the surrounding mantle and consequently cause directional dependence of the seismic velocities, which can also affect the results of seismic tomography. This study improved the quality of seismic tomography results by considering the directional dependence of wave speeds in the mantle to elucidate the evolution of the mantle plume and its interaction with the upper plate in Morocco. The imaged low‐velocity conduit below the high‐altitude Moroccan Atlas indicates the lateral travel of the mantle plume originating from the Canary Hotspot in northwest Africa, which may have dragged the surrounding mantle beneath the Moroccan Atlas. Key Points: Teleseismic P‐wave tomography is used in combination with anisotropy models to study the origin of the low‐velocity anomalies below the Moroccan AtlasWe incorporate anisotropy as an a priori constraint in tomography and show the reduction in low‐velocity anomalies below the Moroccan AtlasThe lateral travel of plume material from the Canary Hotspot may be the origin of low‐velocity anomalies [ABSTRACT FROM AUTHOR]

SUMMARY Ubiquitous data stream mining (UDSM) is the process of performing data analysis on mobile, embedded and ubiquitous devices. In many cases, a large volume of data can be mined for interesting and relevant information in a wide variety of applications. Data stream mining requires computationally intensive mining techniques to be applied in mobile environments constrained by analysis of a real-time single pass with limited computational resources. Therefore, we have to ensure that the result is within the error tolerance range. In this paper, we suggest a method for a false-negative approach based on the Chernoff bound for efficient analysis of the data stream. Hence, we consider the problem of approximating frequency counts for space-efficient computation over data stream sliding windows. We show that a false-negative approach allowing a controlled number of frequent itemsets to be missing from the output is a more promising solution for mining frequent itemsets from a ubiquitous data stream. These are simple to implement, and have provable quality, space, and time guarantees. The experimental results have shown that the proposed algorithms achieve a high accuracy of at least 99% and require a small execution time. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY We present the evidence for an anomalous southwest-dipping slab in southern Mexico. The main evidence comes from a clear receiver function image along a seismic line across the Isthmus of Tehuantepec and is also supported by a previous global tomographic model. The slab dips at 35°, is approximately 250 km in length and appears to truncate the Cocos slab at about 120 km depth. We hypothesize that the slab was created by subduction of oceanic lithosphere prior to the collision of the Yucatán Block with Mexico at approximately 12 Ma. This scenario would explain the Chiapas Fold and Thrust Belt as the product of this collision, and its age constrains the date of the event to be in the Miocene. [ABSTRACT FROM AUTHOR]

We determine centroid-moment tensor (CMT) solutions by minimizing waveform differences between observed and simulated seismograms based on an adjoint method. Synthetic seismograms and Fréchet derivatives are calculated based on a spectral-element method. The non-linear adjoint CMT inversion algorithm requires three simulations for each iteration: one 'forward' simulation to obtain synthetics for the current source parameters, one 'adjoint' simulation which involves injecting time-reversed differences between observed and simulated seismograms as simultaneous virtual sources at each of the receivers, and an extra forward simulation to compute the step length in the conjugate-gradient direction. Whereas the vertical component of the adjoint wavefield reflects the radiation pattern near the centroid location, the components of the adjoint strain tensor capture the elements of the moment tensor. We use the method to determine adjoint CMT solutions for two representative southern California earthquakes using recent 3-D crustal model CVM-6.2. The adjoint CMT solutions are in good agreement with classical Hessian-based CMT solutions involving 3-D Green's functions. In general, adjoint CMT inversions require fewer numerical simulations than traditional Hessian-based inversions. This faster convergence holds promise for multiple moment-tensor and kinematic rupture inversions in 3-D earth models. [ABSTRACT FROM AUTHOR]

Abstract: Public concerns about water pollution have led to the assessment of risks associated with waterborne pollutants. The water intake rate is a key exposure factor that needs to be employed in the risk assessment of water contaminants. However, water consumption patterns vary considerably due to many factors, including region, culture, and time. Because limited information is available on the water intake rate in Asian countries, we carried out a nationwide survey using an online questionnaire to assess the direct tap water and beverage consumption within the general Korean population. To measure seasonal variation in water consumption, this survey was conducted twice, in the spring (n =1092) and summer (n =1148) of 2006. Water intake rates were assessed by age, gender, season, and region. The average rate total water intake was 2566.2ml/day (direct tap water 1015.9ml/day; beverage 1073.0ml/day; indirect tap water 477.3ml/day) in the spring. Indirect tap water intake through the consumption of water-rich dishes occupies 18.5% of average total water intake. In the summer, the average consumption of direct tap water and beverages increased by up to 19.7 and 7.6%, respectively. For the exposure assessment of water related environmental contaminants, a value of 1493mg/L is proposed as a central tendency value and for a reasonable maximum, a value of 2914mg/L (90th percentile) is suggested. This exposure factor may be used in regions with geographic and ethnic characteristics similar to Korea. [Copyright &y& Elsevier]

Abstract: Aim of the study: Although treatment with the essential oil of lavender induces neuroemotional changes, there is a lack of data regarding its specific effects on neurotransduction, especially dopaminergic neurotransduction. We investigated the relationship between altered motor activity and changes in the expression of dopamine receptors (DR), particularly the receptor subtypes D2 and D3, in lavender oil-treated mice. Materials and methods: After the administration of lavender oil (intraperitoneal injections of 10–1000mg/kg lavender oil once per day for 5 days), motor coordination and dopamine receptor expression were examined in the olfactory bulb and the striatum of the mouse brain. Results: After 5 days, mice treated with 1000mg/kg lavender oil showed significantly increased rotarod activity when compared to controls. Although DRD2 expression showed no change in the olfactory bulb or striatum of lavender-treated mice, DRD3 expression increased significantly in the olfactory bulb; this increase was dose-dependent and was observed at both the mRNA and protein levels. Conclusions: These data indicate that altered dopamine D3 receptor subtype homeostasis in the olfactory bulb may contribute to lavender oil-induced behavioral change. [Copyright &y& Elsevier]

Abstract: Surfactin is one of the most powerful biosurfactants, and is known to have antibiotic, anti-tumor and anti-inflammatory functions. In this study, we investigated the effect of surfactin on antigen-presenting property of macrophages. Thioglycollate-elicited mouse peritoneal macrophages were tested for surface molecule expression, cytokine production, phagocytosis, capacity to induce T cell activation by mixed lymphocyte reaction, and underlying signaling pathways. Surfactin significantly suppressed lipopolysaccharide-induced expression of CD40, CD54, CD80, and MHC-II, but not of CD86 and MHC-I. Surfactin-treated macrophages also exhibited impaired phagocytosis and reduced IL-12 expression. And surfactin markedly inhibited the activation of CD4+ T cells. Impaired translocation and activation of NF-κB p65 were founded on macrophages exposed to surfactin. In addition, surfactin inhibited the phosphorylation and degradation of IκB-α, and suppressed the activation of IKK, Akt, JNK and p38 kinase. These results suggest that surfactin impair the antigen-presenting function of macrophages by inhibiting the expression of MHC-II and costimulatory molecules via suppression of NF-κB, p38, JNK and Akt. These novel findings provide new insight into the immunopharmacological role of surfactin in autoimmune disease and transplantation. [Copyright &y& Elsevier]

We collected influent and effluent samples from four sewage treatment plants (STPs) as well as surface water samples in Han River of Seoul, Korea, in three sampling events representing different flow conditions, i.e., April, June, and August, 2005, and analyzed for eleven pharmaceuticals including acetaminophen, caffeine, carbamazepine, cimetidine, diltiazem, trimethoprim, and five sulfonamide antibiotics, using LC-MS-ESI. Pharmaceuticals of high annual production amount were detected in higher level in STP influents. Levels of pharmaceutical residues in the influents were the highest for acetaminophen (average 27,089 ng/L), followed by caffeine (23,664 ng/L), cimetidine (8045 ng/L), and sulfamethoxazole (523 ng/L). Levels of acetaminophen and caffeine in STP effluents were very low compared to the influent concentrations. However cimetidine was detected in relatively high levels even in STP effluent samples. In effluent samples, cimetidine showed the highest level (5380 ng/L), followed by caffeine (278 ng/L), sulfamethoxazole (193 ng/L), and carbamazepine (111 ng/L). The concentration of cimetidine was also the highest in surface water samples (average 281 ng/L), which is the highest level reported from surface water worldwide to our knowledge. Caffeine (268.7 ng/L), acetaminophen (34.8 ng/L), and sulfamethoxazole (26.9 ng/L) were also detected in relatively high levels. Levels of pharmaceuticals detected in surface water samples upstream STPs were generally very low compared to the downstream samples, suggesting that the STPs potentially be a major source of the test pharmaceuticals into Han River. The hazard quotients (HQs) were calculated for the test pharmaceuticals based on their occurrences in surface water, and no pharmaceutical resulted in HQ greater than one, suggesting that their potential environmental impact may be low. [Copyright &y& Elsevier]

Abstract: Pharmaceutical residues may have serious impacts on nontarget biological organisms in aquatic ecosystems, and have therefore precipitated numerous investigations worldwide. Many pharmaceutical compounds available on the market need to be prioritized based on their potential ecological and human health risks in order to develop sound management decisions. We prioritized veterinary pharmaceuticals in Korea by their usage, potential to enter the environment, and toxicological hazard. Twenty compounds were identified in the top priority class, most of which were antibiotics. Among these compounds, 8 were identified as deserving more immediate attention: amoxicillin, enramycin, fenbendazole, florfenicol, ivermectin, oxytetracycline, tylosin, and virginiamycin. A limitation of this study is that we initially screened veterinary pharmaceuticals by sales tonnage for veterinary use only. However, this is the first attempt to prioritize veterinary pharmaceuticals in Korea, and it provides important concepts for developing environmental risk management plans for such contaminants in aquatic systems. [Copyright &y& Elsevier]

Cartap and cypermethrin, which are among the most widely used pesticides in many countries, are considered safe because of their low mammalian toxicity and their low persistence in the environment. However, recent findings of endocrine-disrupting effects and developmental neurotoxicity have raised concerns about the potential ecological impacts of these pesticides. We evaluated the aquatic toxicity of cartap [S,S'-(2-dimethylaminotrimethylene) bis(thiocarbamate), unspecified hydrochloride] and cypermethrin [(RS)-alpha-cyano-3-phenoxybenzyl-(1RS,3RS,1RS,3SR)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate], both individually and combined, on different life stages of the freshwater cladoceran Daphnia magna and a freshwater teleost, Japanese medaka (Oryzias latipes). The 96-hr Daphnia median effective concentrations (EC50s) for cartap and cypermethrin were 91.0 μ g/L and 0.00061 μ g/L, respectively. Rapid recovery of Daphnia was observed after short-term pulsed exposure to cartap and cypermethrin; there were no adverse effects on reproduction or survival 20 d after a 24 hr exposure to cartap up to 1240 μ g/L and cypermethrin up to 1.9 μ g/L. Chronic continuous exposure (for 21 d) of 7-d-old Daphnia to cypermethrin significantly reduced the intrinsic population growth rate in a concentration-dependent manner. However, because the intrinsic population growth rates were all above zero, populations did not decrease even at the highest experimental concentration of 200 ng/L. Exposure of Daphnia neonates (< 24 hr old) to cypermethrin for 21 d caused significant, sub-lethal reproduction-related problems, such as increased time to first brood, reduced brood size, and reduced total brood number, at 0.0002, 0.002, and 0.2 ng/L cypermethrin, but the intrinsic population growth rate was not significantly affected. Oryzias latipes was relatively more resistant to both pesticides. In particular, embryos appeared to be more resistant than juveniles or adults, which may be partly due to the protective role of the chorion. The incidence of larval fish deformity was significantly higher after a 96 hr exposure to as low as 250 μ g/L of cartap or 40 μ g/L of cypermethrin. The mixture of both compounds showed no synergistic toxicity. The extremely high acute-to-chronic ratio suggests that the standard acute lethal toxicity assessment might not reflect the true environmental hazards of these frequently used pesticides. Ecological hazard assessments of long-term low dose or pulsed exposures to cartap and cypermethrin may reveal more realistic consequences of these compounds in surface water. [ABSTRACT FROM AUTHOR]

Pharmaceuticals are manufactured and used for specific biological functions in veterinary and human medicine. Their detection in the environment and their bioactivity have resulted in concern for potential adverse effects on non-target species. Notwithstanding recent attention for their occurrence in the environment, there are significant research gaps for existing pharmaceuticals with regard to their potential ecological consequences. In this study, the four most abundantly used pharmaceuticals in Korea, namely acetaminophen, carbamazepine, cimetidine, and diltiazem, and six sulfonamide related antibiotics, including sulfamethoxazole, sulfachlorpyridazine, sulfathiazole, sulfamethazine, sulfadimethoxine, and trimethoprim were examined for their acute aquatic toxicity employing a marine bacterium (Vibrio fischeri), a freshwater invertebrate (Daphnia magna), and the Japanese medaka fish (Oryzias latipes). In general, Daphnia was the most susceptible among the test organisms. The most acutely toxic among the chemicals tested in this study was diltiazem, with a median lethal concentration of 8. 2 mg/L for D. Magna. The resulting acute toxicity of these pharmaceuticals was reasonably predicted by physicochemical descriptors such as pH-dependent distribution coefficient and E HOMO − E LUMO gap. Predicted environmental concentrations (PECs) derived for the test pharmaceuticals in Korea ranged between 0. 14 and 16. 5 μg/L. Hazard quotients derived from PECs and predicted no effect concentrations (PNECs) for sulfamethoxazole and acetaminophen were 6. 3 and 1. 8, respectively, suggesting potential environmental concerns and a need for further investigation. [Copyright &y& Elsevier]

Ca2+ and Ca2+/calmodulin-dependent protein phosphatase calcineurin (CN) have been known to play crucial roles in immune response and inflammation. Using mouse peritoneal macrophages and RAW 264.7 macrophage cells, we demonstrated that LPS mobilized intracellular free Ca2+ and induced CN phosphatase activity. iNOS expression and NO secretion in response to LPS were suppressed by Ca2+ antagonists (TMB-8, BAPTA/AM, and nifedipine) and CN inhibitor (cyclosporin A). Transient expression of constitutively active CN in mouse peritoneal macrophages and RAW 264.7 macrophages strongly activated NF-κB, a key mediator of iNOS expression. We also found that CN mediates NF-κB activation via IκB-α hyperphosphorylation and degradation. Overexpression of dominant negative mutant of IKKα and -β demonstrates that only IKKβ is the target for CN. These results indicate that CN is required for full iNOS expression and the effective activation of NF-κB in RAW 264.7 and peritoneal macrophages. [Copyright &y& Elsevier]

The 2016 magnitude (MW) 5.5 Gyeongju earthquake, which occurred in Korea near assumed epicenters of several substantial historical earthquakes and Quaternary fault segments, underscores the importance of seismic hazard assessment in the region. However, uncertainties about potential seismic sources make evaluating the potential for a moderate-to-large earthquake challenging. Microearthquake monitoring through a dense seismic network can provide crucial insights into the regional seismic characteristics. An extensive temporary seismic array known as the Gyeongju Hi-density Broadband Seismic Network (GHBSN) was established to investigate microearthquake activity in the southeastern Korean Peninsula. This included the zone of aftershocks from the 2016 Gyeongju earthquake sequence. The GHBSN comprises 200 broadband stations located at approximately 4.5 km intervals in an area of approximately 60 × 60 km2 around the epicenter of the mainshock. A total of 4,773 events were detected from November 2017 to December 2021, including 3,935 events within the GHBSN. The detected events were categorized into five seismic regions excluding quarry blasting sites, that is, the 2016 Gyeongju earthquake region, eastern part of the Ulsan Fault, 2017 Pohang earthquake region, eastern offshore Gyeongju, and western part of the Miryang Fault. A local magnitude scale was developed for the southeastern Korean Peninsula using events detected through the GHBSN. This reflects the distance attenuation and site conditions of the GHBSN stations for earthquakes. An event catalog was created using two automatic detection methods based on the measurement of the energy ratio. This provided high-resolution hypocenter parameters at a completeness magnitude (MC) of 0.0 despite the seismic environment of the network being exposed to high cultural noise. The Gutenberg-Richter b-value was estimated as 0.82 ± 0.02 for all events and 1.01 ± 0.02 for those inside GHBSN. This implies that the seismicity reflects a representative intraplate seismic environment. Testing the obtainability of the focal mechanism solutions showed that the GHBSN outperformed the regional network. Depending on the relationship between the magnitude and frequency of earthquakes, a relatively large number of small earthquakes can provide detailed information on the geometric properties of the causative faults and the state of the acting stress. High-precision microearthquake observation and analysis through GHBSN could provide an unprecedented opportunity with seismic datasets to understand the seismogenesis of the southeastern Korean Peninsula, including the zone of aftershocks of the 2016 Gyeongju earthquake. [ABSTRACT FROM AUTHOR]

Describes the value of Piaget's equilibrium theory for understanding characteristics of the young gifted child. Discussion of the key elements of equilibration theory; Differences in equilibration patterns in gifted children; Universal stages of development.

The glycine decarboxylase multienzyme complex (EC 2.1.210) is located in the mitochondrial matrix and catalyzes a key reaction of the photorespiratory C-2 cycle of plants. The light-dependent control of the synthesis of the P-protein of this complex in pea (Pisum sativum cv. Alaska) leaves was studied using a partial (0.7 kb) cDNA clone. The size of the P-protein mRNA detected by this probe was 3.5 kb. When the mRNA hybrid selected by this probe was translated in vitro, a protein that migrated in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) with an apparent molecular mass of 114 kDa was formed. This protein could be immunoprecipitated with the P-protein-specific antibody. The mass of the mature P-protein on SDS-PAGE is 100 kDa. This suggests the presence of a presequence used to direct the protein to the mitochondrial matrix. Analysis of the concentration of P-protein mRNA showed an approximately 5-fold increase in the abundance of this transcript in light-grown as compared to dark-grown pea seedlings. The time course for the production of P-protein mRNA following exposure of dark-grown peas to white light was compared to that for the H-protein of glycine decarboxylase, the small subunit of ribulose bisphosphate carboxylase/oxygenase. and the chlorophyll alb binding protein. All 4 mRNAs accumulated with similar kinetics where they remained low during the first 3 h of illumination, increased about 5-fold during the next 8 h. and then maintained a steady state over the next 12 h. [ABSTRACT FROM AUTHOR]

In this study, we probe the misalignment of 200 temporary broadband seismometers based on the polarization of P waves from regional and teleseismic earthquakes. The seismometers were deployed in the epicentral region of 2016 ML 5.8 Gyeongju earthquake, South Korea, and this unprecedented dense array provided a unique opportunity for investigating fault structures from microseismicity. For the full use of three-component seismic records, we estimate and provide time-dependent misorientation angles of the 200 seismometers from June 2018 to March 2021 with uncertainty assessments. Two methods based on the principal component analysis and the minimization of transverse P-wave energy are applied. Our estimates are characterized by small uncertainty (average median absolute deviation of 3.14°). Moreover, periods of suspected temporal changes in misorientation angles mostly coincide with periods of reported technical operations, which demonstrates reliability of our methods to precisely detect the temporal variation of misorientation angles. We expect our misorientation angles to serve as an essential metadata for further seismological researches utilizing the dense array data. [ABSTRACT FROM AUTHOR]

Seismic anisotropy of polycrystalline materials depends on the characteristics of microcracks as well as the crystallographic orientations of minerals. Here, we present a MATLAB-based software, AnisEulerSC (Anis otropy from Euler angles using S elf- C onsistent approximation), for modeling the anisotropic seismic properties of a polycrystalline aggregate with microcracks using the self-consistent approximation. In this program, several commands of MTEX (a MATLAB toolbox for texture analysis) are utilized to analyze constituent components of a rock sample based on experimental measurement data (e.g., electron backscatter diffraction) and to calculate and visualize seismic wave velocities and polarizations. We provide several examples of SC modeling to explore the effects of grain shapes on a polycrystalline aggregate and the effects of crack shapes and orientations on the anisotropic seismic properties of a polycrystalline aggregate. [ABSTRACT FROM AUTHOR]

Reliable information on the horizontal orientation of a seismometer is crucial to seismological research utilizing three-component seismograms. In this study, we provide misorientation angles of broadband seismometers in three permanent networks in South Korea from 2003 to 2021 by using two methods, denoted as PPCA and PminT, both utilizing P-wave polarization characteristics. Our estimates show that 36% of the sensors have been aligned within 5° from the geographic north during their operation periods, while 40% of the sensors have been rotated by more than 10° at least once. The estimates are highly consistent for both methods, with 95% of the total showing uncertainty less than 10°. Moreover, we identified a significant number of temporal changes in misorientation by taking automatic change point detection and visual inspection. The procedure described here and misorientation angles can be useful reference for seismic data preprocessing for research utilizing horizontal-component seismograms for earthquake sciences. [ABSTRACT FROM AUTHOR]

• We present 3D seismic attenuation (Q) model of the Nazca Plate subduction zone. • Our model shows clear high- Q slab and low- Q continental plate structures. • Our model for the Brazilian Shield shows high- Q at 40–80 km depth in the backarc. • Along-arc slab Q variations indicate different slab hydration states. • Relatively high- Q at the mantle wedge corner indicates cold thermal state. Seismic attenuation provides key constraints on understanding the structure and dynamics of subduction-zone system. In this study, we provide the first three-dimensional P and S -wave attenuation models beneath the Nazca-South America subduction zone by inverting t * data from 397 local shallow and intermediate-depth earthquakes. The study area covers the southern part of the Peruvian flat-slab region (11°–15 °S) (where the subducting Nazca Ridge is migrating), and the Central Andean Plateau (∼13°–18 °S) (associated with the subducting Nazca Plate) and the Brazilian mantle lithosphere. We obtain five major features in our attenuation model with seismicity including (1) well-defined along-strike and along-dip Nazca slab structure in terms of low attenuation, (2) high attenuation associated with the passage of Nazca Ridge and present location of the oceanic ridges, (3) high attenuation in the backarc mantle wedge and continental crust, (4) clear image of Brazilian Shield in terms of low attenuation, underthrusting to the west, and (5) high attenuation related to the slab dehydration beneath the volcanic arc at 100 and 200 km depths. In particular, prominent low- Q zones in the continental crust and mantle wedge beneath the active volcanic arc reflect source zones of arc magmatism caused by fluids from the slab dehydration. The observed along-arc differences in slab Q estimates can be attributed to different hydration states between the flat and normal-dip slabs due to the subduction of the Nazca Ridge. [ABSTRACT FROM AUTHOR]

The present study describes evaluation of epigenetic regulation by a small molecule as the therapeutic potential for treatment of Huntington's disease (HD). We identified 5-allyloxy-2-(pyrrolidin-1-yl)quinoline (APQ) as a novel SETDB1/ESET inhibitor using a combined in silico and in vitro cell based screening system. APQ reduced SETDB1 activity and H3K9me3 levels in a HD cell line model. In particular, not only APQ reduced H3K9me3 levels in the striatum but it also improved motor function and neuropathological symptoms such as neuronal size and activity in HD transgenic (YAC128) mice with minimal toxicity. Using H3K9me3-ChIP and genome-wide sequencing, we also confirmed that APQ modulates H3K9me3-landscaped epigenomes in YAC128 mice. These data provide that APQ, a novel small molecule SETDB1 inhibitor, coordinates H3K9me-dependent heterochromatin remodelling and can be an epigenetic drug for treating HD, leading with hope in clinical trials of HD. [ABSTRACT FROM AUTHOR]

We used local P and S waves, and regional Lg waves to investigate the Mw 4.9 Offshore Jeju Island earthquake, whose records show evidence of a complex rupture. This earthquake provides a rare window to understand the seismogenesis of moderate‐sized earthquakes on the southern Korea–East China Sea continental shelf. We computed the relative source time functions (RSTFs) by aligning the signals on the origin time of the main and its empirical Green's function (EGF) events, allowing us to use them as differential times of the EGF pair. We determined subevent locations using direct‐wave RSTFs, and captured the rupture variability of the two large subevents using waveform inversion of stacked Lg‐wave RSTFs. The first subevent rupture started by two weak nucleation phases and propagated slowly and bilaterally. Then the second subevent ruptured westward. Our analysis demonstrates that the Lg‐wave train observed at regional distances is useful in investigating detailed slip history. Plain Language Summary: In‐depth studies of small‐to‐moderate‐sized earthquakes in offshore regions are often limited by sparse seismographic station coverage and a lack of close observations. Here, we demonstrate the effective use of local P and S waves and regional Lg waves to investigate the detailed rupture process of the 2021 Mw 4.9 Offshore Jeju Island, Korea earthquake. Lg wave is a guided S wave composed of a superposition of post‐critical reflections in the crust. Detailed seismological analyses using Lg waves revealed that earthquake rupture processes can be spatially complex even in areas with low seismic activity. Our analysis demonstrates that the Lg wave observed at distances greater than 150 km from the epicenter alleviates the limited local station coverage and can be a very useful signal to image the detailed slip history of the earthquake. Our analysis revealed the rupture complexity of the earthquake, expressed as a cascade of four sequential ruptures consisting of two small nucleation phases and two large subevents. Such detailed knowledge of earthquake rupture evolution is critical for understanding seismogenesis in this stable continental region setting. Key Points: We demonstrate an approach to capture the complex rupture process of an offshore moderate‐sized earthquake using limited observationsDirect P and S waves and Lg waves are used to image a spatiotemporal slip history of the Mw 4.9 Offshore Jeju Island, Korea earthquakeResults show a cascading rupture of four subevents on a fault, offering a deeper understanding of event mechanism in low‐seismicity regions [ABSTRACT FROM AUTHOR]

We present a MATLAB-based software (AnisEulerSC; Anisotropy Euler angle Self-Consistent) for calculating the anisotropic seismic properties of a polycrystalline aggregate using the self-consistent (SC) approximation. AnisEulerSC was based on the algorithm that is originally written in FORTRAN77 by Mainprice (1997) using the SC formulation of Willis (1977), which was developed to make models of polycrystalline multi-mineral rocks with variable shapes. The shape becomes more important when the elastic contrast is large between inclusions and background medium. If included cracks are empty, their shapes have strong influence on the seismic anisotropy of rocks. For fluid-filled cracks, the influence of shape decreases with increasing fluid bulk modulus. If cracks are filled with a background mineral, there is almost no influence of the shape (e.g. Anderson et al., 1974). AnisEulerSC can be used to model the effects of empty cracks on the seismic properties of the aggregate. For the AnisEulerSC program, single crystal elastic constants, density, volume fraction of each component, and orientation data in Bunge, Roe or Matthies Euler angles (e.g., EBSD; electron backscatter diffraction or U-stage; universal stage) are required as input data; grain (crystal) orientations and modal mineral composition as well as single crystal elastic tensors. Using EBSD data with grains their areas, mean crystal orientations, and shape (long and short axes) orientations will be determined by a MTEX script. The elastic tensors will be imported directly via the script from a database. Based on the script input parameters, which are crystal orientation, area, shape, and elastic tensors, are used to define the initial aggregate as Voigt, Reuss or Hill average. Options exist to define the grain shape in specimen coordinates for each mineral for modeling. The initial aggregate (e.g., Voigt) is chosen as the starting aggregate for the SC method replacing the unknown background medium, and the procedure is repeated for all inclusions (grains) and repeated iteratively until the solution converges. The convergence of the elastic constants can be plotted. After the SC loop converges, the 21 elastic constants of a SC aggregate and the phase velocities of compressional (Vp), fast shear (Vs1), and slow shear (Vs2) waves are obtained as outputs. [ABSTRACT FROM AUTHOR]

The southeastern Korean Peninsula (SeKP) has experienced intense deformation owing to subduction and backarc extension at the eastern continental margin of the Eurasian Plate, leading to the formation of complex tectonic structures. Abnormally high surface heat flux, Cenozoic volcanism, signatures of mantle degassing and hydrothermal alteration, and several active fault systems with extensional sedimentary basins have been identified; however, the major driving forces that promote local seismic events and hydrothermal activities remain enigmatic. Here, we constructed 3-D P -wave velocity of the crust and upper mantle in the SeKP for the first time using a teleseismic traveltime tomography method and an extensive data set obtained from a dense seismic network. Our model revealed three distinct velocity patterns at different depths: (1) in the upper crust (depth ∼0–10 km), a low-velocity anomaly beneath the Cenozoic sedimentary basin exhibiting a prominent lateral velocity contrasts with higher velocities in the Cretaceous sedimentary and plutonic rocks; (2) a N–S trending low-velocity anomaly extending from the lower crust to the uppermost mantle (depth ∼20–35 km) beneath the major active fault systems interpreted as a thermally or mechanically weakened structure that could transfer high surface heat flux and transport mantle-driven gases and (3) a low-velocity anomaly adjacent to the Cenozoic basin in the upper mantle at depths of 35–55 km interpreted as the higher temperature upper mantle. Via a series of geodynamic simulations, we demonstrated that the extensional deformation at the eastern continental margin during the Early to Middle Miocene locally enhanced the temperature of the crust and upper mantle beneath the SeKP. We propose that a hydrothermal system, resulting from the thermally modified lithosphere of the continental margin, has contributed to the enhanced local seismicity and geothermal activities observed in the SeKP region. [ABSTRACT FROM AUTHOR]

Coupled poroelastic stressing and pore-pressure accumulation along pre-existing faults in deep basement contribute to recent occurrence of seismic events at subsurface energy exploration sites. Our coupled fluid-flow and geomechanical model describes the physical processes inducing seismicity corresponding to the sequential stimulation operations in Pohang, South Korea. Simulation results show that prolonged accumulation of poroelastic energy and pore pressure along a fault can nucleate seismic events larger than Mw3 even after terminating well operations. In particular the possibility of large seismic events can be increased by multiple-well operations with alternate injection and extraction that can enhance the degree of pore-pressure diffusion and subsequent stress transfer through a rigid and low-permeability rock to the fault. This study demonstrates that the proper mechanistic model and optimal well operations need to be accounted for to mitigate unexpected seismic hazards in the presence of the site-specific uncertainty such as hidden/undetected faults and stress regime. [ABSTRACT FROM AUTHOR]

Degeneration of the retinal pigmented epithelium (RPE) and aberrant blood vessel growth in the eye are advanced-stage processes in blinding diseases such as age-related macular degeneration (AMD), which affect hundreds of millions of people worldwide. Loss of the RNase DICER1, an essential factor in micro-RNA biogenesis, is implicated in RPE atrophy. However, the functional implications of DICER1 loss in choroidal and retinal neovascularization are unknown. Here, we report that two independent hypomorphic mouse strains, as well as a separate model of postnatal RPE-specific DICER1 ablation, all presented with spontaneous RPE degeneration and choroidal and retinal neovascularization. DICER1 hypomorphic mice lacking critical inflammasome components or the innate immune adaptor MyD88 developed less severe RPE atrophy and pathological neovascularization. DICER1 abundance was also reduced in retinas of the JR5558 mouse model of spontaneous choroidal neovascularization. Finally, adenoassociated vector-mediated gene delivery of a truncated DICER1 variant (OptiDicer) reduced spontaneous choroidal neovascularization in JR5558 mice. Collectively, these findings significantly expand the repertoire of DICER1 in preserving retinal homeostasis by preventing both RPE degeneration and pathological neovascularization. [ABSTRACT FROM AUTHOR]

The photoluminescence (PL) in monolayer (1L) WS2 greatly varies depending on its electron density. A “chemical tuner” for PL variation in 1L WS2, is described by Y. M. Jhon and co‐workers on page 7551. Hydrogen and/or fluorine plasma treatments allow for tuning of the PL brightness in a reversible way for unlimited cycles. Even a small amount of fluorine dopants significantly brighten PL in 1L WS2 due to their strong electron affinity. The approach is successfully applied in NH3 gas sensing. [ABSTRACT FROM AUTHOR]

Highlights • Pn waveforms are sensitive to the gradients of crust-mantle transition zone (CMTZ). • Southern Korea features sharp Moho while eastern China Moho shows variability. Abstract The seismic velocity structure of the crust-mantle transition zone (CMTZ) provides key constraints on crustal dynamics, and can be studied with Pn wave which propagates horizontally along the Moho discontinuity. In this study, we first explore an effect of velocity-gradient structures in the CMTZ through synthetic Pn waveforms, and demonstrate that the shape of Pn changes from step-like to pulse-like when the CMTZ becomes from sharp to a gradient velocity structure, respectively. We then use Pn waveforms of the regional earthquakes (the July 2012 Mw 4.8 earthquake in east China and the September 2016 Mw 5.1 earthquake in South Korea) to examine the CMTZ structures to the west and east of the Yellow Sea and thus to constrain tectonic affinity between the eastern China and southern Korean Peninsula. The Pn waveforms from the Mw 4.8 event in east China show that the Moho in southern Yangtze Craton is sharp whereas there may be a gradient structure in CMTZ with a 6–10 km thickness in northern Yangtze Craton. The Pn waveforms from the Mw 5.1 event in South Korea show that the CMTZ in South Korea is also sharp, similar to the southern Yangtze Craton. Observed difference in CMTZ structures suggest that Sulu Orogenic Belt may extend along the north of the Gyeonggi Massif in Korea. [ABSTRACT FROM AUTHOR]

We analyze seismic records collected at the oldest (170–180 Ma) Pacific seafloor using broadband dispersion array analysis. Using ambient noise and teleseismic waveforms, we measure Rayleigh‐wave phase velocities in a period range of 5–200 s that are inverted for array‐average one‐dimensional isotropic and azimuthally anisotropic shear‐wave velocity depth profiles from the crust to a depth of 300 km. The high‐velocity Lid and the low‐velocity zone are well‐resolved with velocity difference of ∼4%, whose transition occurs at depths between 80 and 100 km. The profile is compared with that obtained at the 130‐ and 140‐Ma seafloor. Accounting for the cooling effect due to the plate age difference, the low‐velocity zone of the oldest Pacific seafloor is ∼1.3% slower (∼110°C warmer) than that beneath the 140‐Ma seafloor, suggesting the occurrence of some reheating process beneath the oldest lithosphere. The azimuthal anisotropy at shallow depths (<50 km) is significantly different between the western and eastern areas of the array where the peak‐to‐peak amplitudes are estimated to be ∼2.8% and ∼1.6%, respectively. The fast direction is nearly parallel to the past seafloor spreading direction (perpendicular to the magnetic lineation) in the west, while it largely deviates in the east. The observed difference in azimuthal anisotropy may represent complicated evolution dynamics of the infant Pacific plate that involved a ridge‐ridge‐ridge triple junction. Plain Language Summary: One of the classical enigmas of plate tectonics is the cause of seafloor flattening where the seafloor depth becomes nearly constant for old ages (>∼70 Ma) while a simple cooling model of plate evolution predicts the age dependence. To solve this enigma, it is essential to resolve the subsurface structure of the oceanic plate and the asthenosphere below. As a part of an international effort, Pacific Array, that aims to cover the Pacific seafloor by arrays of ocean bottom seismometers, a team of Japanese and Korean scientists deployed an array in the oldest (170–180 Ma) Pacific seafloor. We determine isotropic and anisotropic shear‐wave velocity structures as a first step toward resolving the enigma. The results indicate that the asthenosphere beneath the oldest Pacific lithosphere is significantly slower than the prediction of the simple cooling and that the occurrence of some reheating process may be needed. Furthermore, azimuthal anisotropy (the dependence of the wave velocity on the horizontal propagation direction) in the shallow lithosphere shows that the anisotropy patterns differ between the eastern and western areas of the array, and simulation results indicate that the evolution process of the infant Pacific plate is not merely a simple triangular plate spreading. Key Points: Broadband Rayleigh‐wave dispersion array analysis has been conducted in the oldest (∼170 Ma) Pacific seafloorThe low‐velocity zone is significantly slower to indicate the occurrence of some reheating process beneath the oldest Pacific lithosphereThe spatial variation of the shallow azimuthal anisotropy indicates a complicated evolution of the infant Pacific plate [ABSTRACT FROM AUTHOR]

We investigated monomethylmercury (MMHg) concentrations in 448 samples of four common fish species (barbel steed, largemouth bass, leopard mandarin, and bluegill) and the trophic states of 14 artificial reservoirs in South Korea in order to understand how trophic states of reserviors affect MMHg concentrations in fish. The trophic state index (TSI) of each reservoir was determined using empirical equations based on the monthly chlorophyll-a, total phosphorus, and Secchi depth, collected over a three-year period. The length-normalized MMHg concentrations in fish showed a negative correlation with the TSI based on chlorophyll-a (r 2 = 0.90) and total phosphorus (r 2 = 0.75) that may be a result of particle dilution of MMHg in surface waters. This study revealed that MMHg accumulation in fish was better correlated with TSI than MMHg in water, therefore, we suggest that the measurement of TSI based on chlorophyll-a and total phosphorus is an effective way to predict MMHg bioaccumulation across diverse reservoirs. [ABSTRACT FROM AUTHOR]

The moment magnitude (Mw) 5.4 Pohang earthquake, the most damaging event in South Korea since instrumental seismic observation began in 1905, occurred beneath the Pohang geothermal power plant in 2017. Geological and geophysical data suggest that the Pohang earthquake was induced by fluid from an enhanced geothermal system (EGS) site, which was injected directly into a near-critically stressed subsurface fault zone. The magnitude of the mainshock makes it the largest known induced earthquake at an EGS site. [ABSTRACT FROM AUTHOR]