ALBERT

Description: Since explosive and impulsive seismic sources such as dynamite, air guns, gas guns or even vibroseis can have a big impact on the environment, some companies have decided to record ambient seismic noise and use it to estimate the physical properties of the subsurface. Big challenges arise when the aim is extracting body waves from recorded passive signals, especially in the presence of strong surface waves. In passive seismic signals, such body waves are usually weak in comparison to surface waves that are much more prominent. To understand the characteristics of passive signals and the effect of natural source locations, three simple synthetic models were created. To extract body waves from simulated passive signals we propose and test a Radon-correlation method. This is a time-spatial correlation of amplitudes with a train of time-shifted Dirac delta functions through different hyperbolic paths. It is tested on a two-layer horizontal model, a three-layer model that includes a dipping layer (with and without lateral heterogeneity) and also on synthetic Marmousi model data sets. Synthetic tests show that the introduced method is able to reconstruct reflection events at the correct time-offset positions that are hidden in results obtained by the general cross-correlation method. Also, a depth migrated section shows a good match between imaged horizons and the true model. It is possible to generate off-end virtual gathers by applying the method to a linear array of receivers and to construct a velocity model by semblance velocity analysis of individually extracted gathers.

Description: Summary The recently constructed diffuse field theory from isotropic energy equipartition has been well developed in elasticity for full-wave interpretation of Horizontal-to-Vertical Ratio (HVSR), which links the signal autocorrelation with the imaginary part of Green's function. Here, the theory is extended to the saturated layered medium within the framework of Biot's theory to account for the offshore environment. The imaginary parts of Green's functions are obtained using direct stiffness method accompanied with Fourier-Hankel transform. In particular, the up-going wave amplitudes are modified to tackle the overflow during wavenumber integral and allow for fast calculations. After validating the method from the perspectives of Green's function calculation, emphasis is laid on evaluating the inaccuracies of HVSR calculation induced by model misuses in the lack of prior geological and geotechnical information. The numerical results considering the effects of layer sequence, impedance ratio, porosity and drainage condition show that the predominant frequency of the one-phase medium is slightly less than the two-phase medium with the maximum shift no more than 0.1Hz, while their amplitude differences can be prominent as impedance ratio and porosity increase, with the maximum difference up to 29 per cent. The shallowest soft layer has the dominant effects on HVSR amplitudes, whereas the buried low-velocity layer at depth over one-wavelength contributes little to the peak amplitude. Finally, the method is applied to a realistic case at Mirandola, Northorn Italy, which suffered extensive liquefaction-induced damages in 2012 Emilia earthquake. The well identified pattern of the experimental HVSR using the two-phase medium model illustrates the application potential of our method to further assist the subsurface geology retrieval.

Description: Summary Delineating spatial variations of seismic anisotropy in the crust is of great importance for the understanding of structural heterogeneities, regional stress regime and ongoing crustal dynamics. In this study we present a three-dimensional (3-D) anisotropic P-wave velocity model of the crust beneath northern California (2-22 km) by using the eikonal equation-based seismic azimuthal anisotropy tomography method. The velocity heterogeneities under different geological units are well resolved. The thickness of the low-velocity sediment at the Great Valley Sequence is estimated to be about 10 km. The high-velocity anomaly underlying Great Valley probably indicates the existence of ophiolite bodies. Strong velocity contrasts are revealed across the Hayward Fault (2-9 km) and San Andreas Fault (2-12 km). In the upper crust (2-9 km), the fast velocity directions (FVDs) at different depths are generally fault-parallel in the northern Coast Range, which may be caused by geological structure; while the FVDs are mainly NE-SW in Great Valley and the northern Sierra Nevada possibly due to the regional maximum horizontal compressive stress. In contrast, seismic anisotropy in the mid-lower crust (12-22 km) may be attributed to the alignment of mica schists. The anisotropy contrast across the San Andreas Fault may imply different mechanisms of crustal deformation on the two sides of the fault. Both the strong velocity contrasts and the high angle (∼45o or above) between the FVDs and the strikes of faults suggest that the faults are mechanically weak in the San Francisco bay area (2-6 km). This study suggests that the eikonal equation-based seismic azimuthal anisotropy tomography is a valuable tool to investigate crustal heterogeneities and tectonic deformation.

Description: Long noncoding RNAs (lncRNAs) have been considered as novel regulators in oral squamous cell carcinoma (OSCC). Enhancer of zeste homolog 2 (EZH2) can act as an oncogene in OSCC. This study intended to investigate whether lncRNA PART1 can exert its role in OSCC by regulating EZH2. The expression of PART1 in OSCC samples, tumors tissues, or OSCC cell lines was detected by qRT-PCR. The proliferation and apoptosis of OSCC cells were detected by CCK-8 and flow cytometry assays, respectively. The expression of PART1 and EZH2 were highly expressed in clinical OSCC tumors and cell lines. The expression level of PART1 was positively correlated to the size, clinical stage, and node metastasis of OSCC patients. Functionally, PART1 knockdown inhibited proliferation and facilitated apoptosis of OSCC cells. Mechanically, FUS interacted with PART1 and EZH2. Additionally, PART1 knockdown reduced the mRNA expression of EZH2, which was offset by FUS overexpression. The overexpression of FUS abrogated the effects of PART1 silence on proliferation and apoptosis of OSCC cells. The in vivo experiment revealed that PART1 knockdown inhibited tumor growth of OSCC cells in nude mice. This study indicated that PART1 exerts a carcinogenic role in OSCC by enhancing the stability of EZH2 protein.

Description: Summary Surface wave retrieval from ambient noise records using seismic interferometry techniques have been widely used for multiscale shear wave velocity (Vs) imaging. One key step during Vs imaging is the generation of dispersion spectra and the extraction of a reliable dispersion curve from the retrieved surface waves. However, the sparse array geometry usually affects the ability for high-frequency (〉1 Hz) seismic signals acquisition. Dispersion measurements are degraded by array response due to sparse sampling and often present smeared dispersion spectra with sidelobe artifacts. Previous studies usually focus on interferograms domain (e.g., cross-correlation function) and attempt to enhance coherent signals before dispersion measurement. We propose an alternative technique to explicitly deblur dispersion spectra through use of a phase-weighted slant-stacking algorithm. Numerical examples demonstrate the strength of the proposed technique to attenuate array responses as well as incoherent noise. Three different field examples prove the flexibility and superiority of the proposed technique: the first dataset consists of ambient noise records acquired using a nodal seismometer array; the second dataset utilizes Distributed Acoustic Sensing (DAS) and a marine fiber-optic cable to acquire a similar ambient noise dataset; the last dataset is a vibrator-based active-source surface wave data. The enhanced dispersion measurements provide cleaner and higher-resolution spectra without distortions which will assist both human interpreters as well as ML algorithms in efficiently picking curves for subsequent Vs inversion.

Description: Size selection in active fishing gears is a continuous process and undersized fish may escape during the whole fishing operation. Fish that escape during the surface hauling operation are likely to experience higher mortality due to barotrauma-related stress than fish escaping at the fishing depth during the towing process. A well-functioning selectivity device should therefore select mostly at depth for enhancing survival probabilities of escaping fish. The current gear regulation in the Norwegian demersal seine fishery is likely to cause large proportion of undersized fish to escape at the surface. In this study, we estimated surface selection of haddock and cod in demersal seine by using an automatic release system and a small meshed codend that collected fish escaping during surface hauling. The collecting bag contained 19% undersized haddock compared to 10% in the conventional square-mesh codend indicating that about 50% of undersized haddock brought to the surface were released. The proportions of undersized cod were 8% for the collecting bag and 1% for the conventional square-mesh codend. These results demonstrate that surface selection is significant for both haddock and cod. Based on this finding, we discuss methods to improve size selectivity at the fishing depth.

Description: Summary Mt. Merapi, which lies just north of the city of Yogyakarta in Java, Indonesia, is one of the most active and dangerous volcanoes in the world. Thanks to its subduction zone setting, Mt Merapi is a stratovolcano, and rises to an elevation of 2968 m above sea level. It stands at the intersection of two volcanic lineaments, Ungaran–Telomoyo–Merbabu–Merapi (UTMM) and Lawu–Merapi–Sumbing–Sindoro–Slamet, which are oriented north-south and west-east, respectively. Although it has been the subject of many geophysical studies, Mt Merapi's underlying magmatic plumbing system is still not well understood. Here, we present the results of an ambient seismic noise tomography study, which comprise of a series of Rayleigh wave group velocity maps and a 3-D shear wave velocity model of the Merapi-Merbabu complex. A total of 10 months of continuous data (October 2013–July 2014) recorded by a network of 46 broadband seismometers were used. We computed and stacked daily cross-correlations from every pair of simultaneously recording stations to obtain the corresponding inter-station empirical Green's functions. Surface wave dispersion information was extracted from the cross-correlations using the multiple filtering technique, which provided us with an estimate of Rayleigh wave group velocity as a function of period. The group velocity maps for periods 3–12 s were then inverted to obtain shear wave velocity structure using the neighbourhood algorithm. From these results, we observe a dominant high velocity anomaly underlying Mt. Merapi and Mt. Merbabu with a strike of 152° N, which we suggest is evidence of old lava dating from the UTMM double-chain volcanic arc which formed Merbabu and Old Merapi. We also identify a low velocity anomaly on the southwest flank of Merapi which we interpret to be an active magmatic intrusion.

Description: Summary The crustal attenuation structure can effectively reveal the rheology and thermal properties of different geological blocks, and can provide seismological constraints on regional tectonic evolution. Based on 11,306 vertical-component Lg-wave seismograms recorded at 111 broadband stations from 891 crustal earthquakes that occurred between 1994 and 2020, a broadband Lg-wave attenuation model is obtained for Southeast Asia. This study demonstrates the capability of applying crustal Lg wave attenuation inversion in a complex region mixed with continents, islands and marginal seas. The resolution approaches 2 degrees in most parts in the study region. Lg blockages are observed at places with sharp Moho depth changes. The resultant Q models are consistent with regional geologic structures provided by previous studies. Prominent low attenuation anomalies are located in the Sundaland Core containing stable ancient crust, including Indochina, Malay Peninsula, East Sumatra, Sunda Shelf and Borneo Core. Regions with strong attenuation are associated with complex tectonic conditions, such as the Indo-Australian subduction zone, sutures in Sarawak and Sabah. The observed Lg-wave attenuation characteristics provide constraints on the tectonic affinities and evolutions of the geological blocks. The results show that the Borneo Core remained stable since its accretion with the Sundaland Core. Ancient blocks are characterized by weak Lg attenuation, whereas geologically younger terranes are often characterized by strong Lg attenuation, which can be exploited to better understand the separation and convergence of plates during the tectonic evolution.

Description: Background Although it is well documented that adolescents and young adults (AYAs) with cancer have low participation in cancer clinical trials (CCTs), the underlying reasons are not well understood. We utilized the NCI Community Oncology Research Program (NCORP) network to identify barriers and facilitators to AYA CCT enrollment, and strategies to improve enrollment at community-based and minority/underserved sites. Methods We performed one-on-one semi-structured qualitative interviews with stakeholders (NCORP Site Principle Investigators, NCORP Administrators, Physicians involved in enrollment, Lead Clinical Research Associates or Clinical Research Nurses, Nurse Navigators, Regulatory Research Associates, Patient Advocates) in the AYA CCT enrollment process. NCORP sites that included high- and low-AYA enrolling affiliate sites and were diverse in geography and department representation (eg, pediatrics, medical oncology) were invited to participate. All interviews were recorded and transcribed. Themes related to barriers and facilitators and strategies to improve enrollment were identified. Results We conducted 43 interviews across 10 NCORP sites. Eleven barriers and 13 facilitators to AYA enrollment were identified. Main barriers included perceived limited trial availability and eligibility, physician gatekeeping, lack of provider and research staff time, and financial constraints. Main facilitators and strategies to improve AYA enrollment included having a patient screening process, physician endorsement of trials, an “AYA champion” on site, and strong communication between medical and pediatric oncology. Conclusions Stakeholders identified several opportunities to address barriers contributing to low AYA CCT enrollment at community-based and minority/underserved sites. Results of this study will inform development and implementation of targeted interventions to increase AYA CCT enrollment.

Description: Patients, practitioners, and policymakers are increasingly concerned about the delivery of ineffective or low-value clinical practices in cancer care settings. Research is needed on how to effectively de-implement these types of practices from cancer care. In this commentary, we spotlight the National Cancer Institute (NCI) Community Oncology Research Program (NCORP), a national network of community oncology practices, and elaborate on how it is an ideal infrastructure for conducting rigorous, real-world research on de-implementation. We describe key, multi-level issues that affect de-implementation and also serve as a guidepost for developing strategies to drive de-implementation. We describe optimal study designs for testing de-implementation strategies and elaborate on how and why the NCORP network is uniquely positioned to conduct rigorous and impactful de-implementation trials. The number and diversity of affiliated community oncology care sites, coupled with the overall objective of improving cancer care delivery, make the NCORP an opportune infrastructure for advancing de-implementation research while simultaneously improving the care of millions of cancer patients nationwide.

Description: Nutrient loading into coastal sediments is increasing due to anthropogenic activity and climate change. We examined the effects of sediment nutrient enrichment on the growth and reproduction of Zostera marina by adding nitrogen (N) and phosphorus (P) fertilizers into sediments. Areal productivity and shoot density increased by ca. 60% in N and N + P enrichment plots and by ca. 20% in the P enrichment plots. Biomass and shoot height were also higher in the N and N + P enrichment plots than in the P enrichment and control plots. These results suggest that sediment N availability was more important than P availability in stimulating the vegetative growth of Z. marina . The density and morphology of reproductive shoots and seed production increased in only the N enrichment plots. The sediment N enrichment stimulated both the vegetative growth and sexual reproduction, improving the meadow resilience through both sexual and asexual mechanisms. The P enrichment slightly increased only the vegetative growth and might have limited influence on seagrass reproduction. According to these results, the alteration of the sediment nutrient regimes might shift the balance between the vegetative growth and sexual reproduction of Z. marina. These findings may have important implications for the management of seagrass meadows under fluctuations in sediment nutrients caused by anthropogenic activity and climate change.

Description: Summary Shallow seismic sources excite Rayleigh wave ground motion with azimuthally dependent radiation patterns. We place binary hypothesis tests on theoretical models of such radiation patterns to screen cylindrically symmetric sources (like explosions) from non-symmetric sources (like non-vertical dip-slip, or non-VDS faults). These models for data include sources with several unknown parameters, contaminated by Gaussian noise and embedded in a layered half-space. The generalized maximum likelihood ratio tests that we derive from these data models produce screening statistics and decision rules that depend on measured, noisy ground motion at discrete sensor locations. We explicitly quantify how the screening power of these statistics increase with the size of any dip-slip and strike-slip components of the source, relative to noise (faulting signal strength), and how they vary with network geometry. As applications of our theory, we apply these tests to (1) find optimal sensor locations that maximize the probability of screening non-circular radiation patterns, and (2) invert for the largest non-VDS faulting signal that could be mistakenly attributed to an explosion with damage, at a particular attribution probability. Lastly, we quantify how certain errors that are sourced by opening cracks increase screening rate errors. While such theoretical solutions are ideal and require future validation, they remain important in underground explosion monitoring scenarios because they provide fundamental physical limits on the discrimination power of tests that screen explosive from non-VDS faulting sources.

Description: Summary We present a theory of modern, thermally-induced deformation in a realistic Earth. The heat conduction equation is coupled with standard elastic deformation theory to construct a boundary-value problem comprised of eighth-order differential equations. The accurate and stable dual variable and position propagating matrix technique is introduced to solve the boundary-value problem. The thermal load Love numbers are defined to describe the displacements and potential changes driven by thermally-induced deformation. The proposed analytical method is validated by comparing the present results with exact solutions for a homogeneous sphere, which are also derived in this paper. The analytical method is then applied to a realistic Earth model to evaluate the effects of layering and self-gravitation of the Earth on displacement and changes of potential. Furthermore, the frequency-dependence in the thermal load is illustrated by invoking different thermal periodicities in the computation. Thermal anisotropy is also considered by comparing the results obtained using isotropic and transversely isotropic Earth models. Results show that, when simulating thermally-induced deformation, invoking a homogeneous spherical Earth leads to results that substantially differ from those obtained using a more realistic Earth model.

Description: I describe lessons learned and the people and principles that influenced six decades of professional endeavours from graduate schools to ascending, often unexpectedly, the science and management ladder in National Oceanic and Atmospheric Administration (NOAA) fisheries, which manages US living marine resources. For this woman chemist from India, the twists of fate and love of adventure presented amazing opportunities as well as challenges. My research on cetacean biosonar as well as on the impact of fossil fuel pollution on seafood safety and the health of marine organisms taught me the value of multidisciplinary approaches and unusual alliances. Transitioning into management, and eventually as the director of Northwest Fisheries Science Center, I learned the value of transparency and empathy while communicating our results to impacted communities, and the resolve to support the science regardless of the consequences. My advice to young professionals is that the journey should be as fulfilling as reaching the goalpost. At the twilight of my own journey, I networked with NOAA Fisheries and India’s marine science community to encourage scientist exchanges and training. My participation in University of Washington’s nature and human health programme confirms my conviction that conserving healthy ecosystems is a powerful and practical approach for people and our planet.

Description: Summary Mantle convection induces dynamic topography, the lithosphere's surface deflections driven by the vertical stresses from sub-lithospheric mantle convection. Dynamic topography has important influences on a range of geophysical and geological observations. Here, we studied controls on the Earth's dynamic topography through three-dimensional spherical models of mantle convection, which use reconstructed past 410 Myr global plate motion history as time-dependent surface mechanical boundary condition. The numerical model assumes the extended-Boussinesq approximation and includes strongly depth- and temperature-dependent viscosity and phase changes in the mantle. Our results show that removing the chemical layer above the CMB and including depth-dependent thermal expansivity have both a limited influence on the predicted present-day dynamic topography. Considering phase transitions in our models increases the predicted amplitude of dynamic topography, which is mainly influenced by the 410 km exothermic phase transition. The predicted dynamic topography is very sensitive to shallow temperature-induced lateral viscosity variations (LVVs) and Rayleigh number. The preservation of LVVs significantly increases the negative dynamic topography at subduction zones. A decrease (or increase) of Rayleigh number increases (or decreases) the predicted present-day dynamic topography considerably. The dynamic topography predicted from the model considering LVVs and with a Rayleigh number of 6 × 108 is most compatible with residual topography models. This Rayleigh number is consistent with the convective vigor of the Earth as supported by generating more realistic lower mantle structure, slab sinking rate, and surface and CMB heat fluxes. The evolution of the surface heat flux pattern is similar to the long-term eustatic sea-level change. Before the formation of Pangea, large negative dynamic topography formed between the plate convergence region of Gondwana and Laurussia. The predicted dynamic topography similar to that of present day has already emerged by about 262 Ma. Powers for degrees 1–3 dynamic topography at 337 Ma and 104 Ma which correspond to times of higher plate velocities and higher surface heat fluxes are larger.

Description: Summary We investigated the induced seismicity, source mechanisms and mechanical responses of a decameter-scale hydraulic stimulation of a pre-existing shear zone in crystalline rock, at the Grimsel Test Site, Switzerland. The analysis reveals the meter-scale complexity of hydraulic stimulation, which remains hidden at the reservoir-scale. High earthquake location accuracy allowed the separation of four distinct clusters, of which three were attributed to the stimulation of fractures in the damage zone of the shear zone. The source mechanism of the larger-magnitude seismicity varied by cluster, and suggests a heterogeneous stress field already prevailing before stimulation, which is further modified during stimulation. In the course of the experiment, stress redistribution led to the aseismic initiation of a tensile-dominated fracture, which induced seismicity in the fourth of the identified seismic clusters. The streaky pattern of seismicity separated by zones without seismicity suggests fluid flow in conduits along existing fracture planes. The observed sub-meter scale complexity questions the forecasting ability of induced seismic hazard at the reservoir scale from small-scale experiments.

Description: Summary Ground observatory and satellite-based determinations of temporal variations in the geomagnetic field probe a decadal to annual time scale range where Earth’s core slow, inertialess convective motions and rapidly propagating, inertia-bearing hydromagnetic waves are in interplay. Here we numerically model and jointly investigate these two important features with the help of a geodynamo simulation that (to date) is the closest to the dynamical regime of Earth’s core. This model also considerably enlarges the scope of a previous asymptotic scaling analysis, which in turn strengthens the relevance of the approach to describe Earth’s core dynamics. Three classes of hydrodynamic and hydromagnetic waves are identified in the model output, all with propagation velocity largely exceeding that of convective advection: axisymmetric, geostrophic Alfvén torsional waves, and non-axisymmetric, quasi-geostrophic Alfvén and Rossby waves. The contribution of these waves to the geomagnetic acceleration amounts to an enrichment and flattening of its energy density spectral profile at decadal time scales, thereby providing a constraint on the extent of the f−4 range observed in the geomagnetic frequency power spectrum. As the model approaches Earth’s core conditions, this spectral broadening arises because the decreasing inertia allows for waves at increasing frequencies. Through non-linear energy transfers with convection underlain by Lorentz stresses, these waves also extract an increasing amount of energy from the underlying convection as their key time scale decreases towards a realistic value. The flow and magnetic acceleration energies carried by waves both linearly increase with the ratio of the magnetic diffusion time scale to the Alfvén time scale, highlighting the dominance of Alfvén waves in the signal and the stabilising control of magnetic dissipation at non-axisymmetric scales. Extrapolation of the results to Earth’s core conditions supports the detectability of Alfvén waves in geomagnetic observations, either as axisymmetric torsional oscillations or through the geomagnetic jerks caused by non-axisymmetric waves. In contrast, Rossby waves appear to be too fast and carry too little magnetic energy to be detectable in geomagnetic acceleration signals of limited spatio-temporal resolution.

Description: The secreted glycoprotein Reelin plays important roles in both brain development and function. During development, Reelin regulates neuronal migration and dendrite development. In the mature brain, the glycoprotein is involved in synaptogenesis and synaptic plasticity. It has been suggested that Reelin loss or decreased function contributes to the onset and/or deterioration of neuropsychiatric diseases, including schizophrenia and Alzheimer’s disease. While the molecular mechanisms underpinning Reelin function remain unclear, recent studies have suggested that the specific proteolytic cleavage of Reelin may play central roles in the embryonic and postnatal brain. In this review, we focus on Reelin proteolytic processing and review its potential physiological roles.

Description: Previous studies have concluded that dehydration of serpentinites in subduction zones produces oxidizing fluids that are the cause of oxidized arc magmas. Here, observations of natural samples and settings are combined with thermodynamic models to explore some of the factors that complicate interpretation of the observations that form the basis of this conclusion. These factors include: the variability of serpentinite protoliths; the roles of carbon and sulfur in serpentinite evolution; variability in serpentinization in different tectonic settings; changes in the bulk compositions of ultramafic rocks during serpentinization; fundamental differences between serpentinization and deserpentinization; and the absence of precise geothermobarometers for ultramafic rocks. The capacity of serpentinite-derived fluids to oxidize sub-arc magma is also examined. These fluids can transport redox budget as carbon-, sulfur-, and iron-bearing species. Iron- and carbon-bearing species might be present in sufficient concentrations to transport redox budget deep within subduction zones, but are not viable transporters of redox budget at the temperatures of antigorite breakdown, which produces the largest proportion of fluid released by serpentinite dehydration. Sulfur-bearing species can carry significant redox budget, and calculations using the Deep Earth Water (DEW) model show that these species might be stable during antigorite breakdown. However, oxygen fugacities of ∼ΔFMQ +3 (where FMQ refers to the fayalite–magnetite–quartz buffer, and ΔFMQ is Log fO2 – Log fO2,FMQ), which is close to, or above, the hematite–magnetite buffer at the conditions of interest, are required to stabilize oxidized sulfur-bearing species. Pseudosection calculations indicate that these conditions might be attained at the conditions of antigorite breakdown if the starting serpentinites are sufficiently oxidized, but further work is required to assess the variability of serpentinite protoliths, metamorphic pressures and temperatures, and to confirm the relative positions of the mineral buffers with relation to changes in fluid speciation.

Description: Beverton and Holt’s (1957. On the dynamics of exploited fish populations. UK Ministry of Agriculture, Fisheries and Food. Fisheries Investigations, 2: 533 pp.) monograph contributed a widely used stock–recruitment relationship (BH-SRR) to fisheries science. However, because of variation around a presumed relationship between spawning biomass and recruits, the BH-SRR is often considered inadequate and approached merely as a curve-fitting exercise. The commonly used and simplified version of the BH-SRR has eclipsed the fact that in their classic monograph, the derivation accounted for mechanistic recruitment processes, including multi-stage recruitment with explicit cohort-dependent and -independent mortality terms that represent competition between recruits and extrinsic, cohort-independent factors such as the environment or predation as two independent sources of mortality. The original BH-SRR allows one to recreate recruitment patterns that correspond to observed ones. Doing so shows that variation in density-independent mortality increases the probability of overlooking an underlying stock–recruitment relationship. Intermediate coefficients of variation in mortality (75–100%) are sufficient to mask stock–recruitment relationships and recreate recruitment time series most similar to empirical data. This underlines the importance of variation in survival for recruitment and that Beverton and Holt’s work still provides a fundamental and useful tool to model the dynamics of populations.

Description: Background Major cancer organizations recommend depression screening in patients and survivors. The Patient Health Questionnaire-9 (PHQ-9) is often suggested, with limited information about its use. Methods Enrollment data collected from younger breast cancer survivors participating in a behavioral intervention trial were used to examine the relationship between PHQ-9 scores (range = 0-27), patient characteristics and responses to standardized psychosocial assessment tools. Major depressive disorder criterion was met if responses to the first two PHQ-9 items (range = 0-6) were 〉3. The sample was categorized by total PHQ-9 scores: 10 (moderate to severe depression). PHQ-9 category associations with medical, demographic, psychosocial and behavioral characteristics were examined using ANOVA for continuous variables and chi-square tests for categorical variables. Results 231 women met the study pre-screening eligibility criterion of mild depressive symptoms and enrolled in the study. On average, they were 45.2 years old and 2.6 years since diagnosis. At enrollment, 22.1% met the screening criterion for possible major depressive disorder; among those with PHQ-9 scores 〉10, 58.3% met this criterion. Anxiety, fatigue, insomnia, and intrusive thoughts about cancer were frequent and were associated with depressive symptom severity (all Ps

Description: I have the pleasure to invite you on my trip—or rather voyage, from childhood to retirement as a fisheries scientist. We will go fishing, do fishing gear and aquaculture research, provide scientific management advice, and cooperate with developing countries along the way. My advice to young scientists is to build trust, have passion for your work, and make it relevant for sustainable development.

Description: Summary The squirt flow model, proposed by Mavko & Jizba, has been widely used in explaining the frequency-related modulus and velocity dispersion between ultrasonic and seismic measurements. In this model, the saturated bulk modulus at high frequency is obtained by taking the so-called unrelaxed frame bulk modulus into Biot's or Gassmann's formula. When using Gassmann's formula, the mineral bulk modulus is taken as matrix bulk modulus. However, the soft pores (cracks) in rocks have a weakening effect on the matrix bulk modulus. The saturated bulk modulus at high frequency calculated with mineral bulk modulus as matrix bulk modulus is higher than the real values. To overcome this shortcoming we propose a modified matrix bulk modulus based on the Betti-Rayleigh reciprocity theorem and non-interaction approximation. This modification takes the weakening effect of soft pores (cracks) into consideration and allows calculating the correct saturated bulk modulus at high frequency under different soft-pore fractions (the ratio of soft porosity to total porosity) or crack densities. We also propose an alternative expression of the modified matrix bulk modulus, which can be directly obtained from laboratory measurements. The numerical results show that the saturated bulk modulus at high frequency using the original matrix bulk modulus (i.e. mineral bulk modulus) is approximated to that using the modified one only for rocks containing a small amount of soft-pore fraction. However, as the soft-pore fraction becomes substantial, using the original bulk matrix modulus is not applicable, but the modified one is still applicable. Furthermore, the results of the modified squirt flow model show good consistency with published numerical and experimental data. The proposed modification extends the applicable range of soft-pore fraction (crack density) of the previous model, and has potential applications in media having a relatively substantial fraction of soft pores or almost only soft pores, such as granite, basalt, and thermally-cracked glasses.

Description: The Quaternary Tarosero volcano is situated in the East African Rift of northern Tanzania and mainly consists of trachyte lavas and some trachytic tuffs. In addition, there are minor occurrences of extrusive basalts, andesites, latites, as well as peralkaline trachytes, olivine trachytes and phonolites. Some of the peralkaline phonolites contain interstitial eudialyte, making Tarosero one of the few known occurrences for extrusive agpaitic rocks. This study investigates the genetic relationships between the various rock types and focuses on the peculiar formation conditions of the extrusive agpaitic rocks using a combination of whole-rock geochemistry, mineral chemistry, petrography, thermodynamic calculations, as well as major and trace element modelling. The Tarosero rocks formed at redox conditions around or below the fayalite-magnetite-quartz buffer (FMQ). During multi-level magmatic fractionation at depths between ∼40 km and the shallow crust, temperature decreased from 〉 1100 °C at near-liquidus conditions in the basalts to ∼ 700 °C in the peralkaline residue. Fractional crystallization models and trace element characteristics do not indicate a simple genetic relationship between the trachytes and the other rock types at Tarosero. However, the genetic relationships between the primitive basalts and the intermediate latites can be explained by high pressure fractional crystallization of olivine + clinopyroxene + magnetite + plagioclase + apatite. Further fractionation of these mineral phases in addition to amphibole and minor ilmenite led to the evolution towards the peralkaline trachytes and phonolites. The eudialyte-bearing varieties of the peralkaline phonolites required additional low-pressure fractionation of alkali feldspar and minor magnetite, amphibole and apatite. In contrast to the peralkaline trachytes and phonolites, the peralkaline olivine trachytes contain olivine instead of amphibole, thus indicating a magma evolution at even lower pressure conditions. They can be modelled as a derivation from the latites by fractional crystallization of plagioclase, clinopyroxene, magnetite and olivine. In general, agpaitic magmas evolve under closed system conditions which impedes the escape of volatile phases. In case of the extrusive agpaitic rocks at Tarosero, the early exsolution of fluids and halogens was prevented by a low water activity. This resulted in high concentrations of Rare Earth Elements (REE) and other High Field Strength Elements (HFSE) and the formation of eudialyte in the most evolved peralkaline phonolites. Within the peralkaline rock suite, the peralkaline olivine trachytes contain the lowest HFSE and REE concentrations, consistent with mineralogical evidence for a formation at a relatively high water activity. The lack of amphibole fractionation, which can act as a water buffer of the melt, as well as the evolution at relatively low pressure conditions caused the early exsolution of fluids and loss of water-soluble elements. This prevented a strong enrichment of HFSE and REE before the magma finally extruded.

Description: Cellular liquid-liquid phase separation is a physiologically inevitable phenomenon in molecularly crowded environments inside cells and serves to compartmentalize biomolecules to facilitate several functions, forming cytoplasmic and nuclear RNA granules. Abnormalities in the phase separation process in RNA granules are implicated in the onset of several neurodegenerative diseases; the initial liquid-like phase-separated droplets containing pathogenic proteins are prone to aberrantly mature into solid-like droplets. RNAs are involved in the maturation of physiological and pathological RNA granules and are essential for governing the fate of phase-transition processes. Notably, RNA G-quadruplex (G4RNA), which is the secondary structure of nucleic acids that are formed in guanine-rich sequences, appears to be an advantageous scaffold for RNA-derived phase separation because of its multivalent interactions with RNAs and RNA-binding proteins. Here, we summarize the properties of RNA granules in physiological and pathological phase separation and discuss the potential roles of G4RNA in granules.

Description: There are more than 90 porphyry (or skarn) Mo deposits in northeastern China with Jurassic or Cretaceous ages. These are thought to have formed mainly in a continental arc setting related to the subduction of the Paleo-Pacific oceanic plate in the Jurassic and subsequent slab rollback in the early Cretaceous. The Jurassic Daheishan porphyry Mo deposit is one of the largest Mo deposits in NE China, which contains 1.09 Mt Mo with an average Mo grade of 0.07%. To better understand the factors that could have controlled Mo mineralization at Daheishan, and potentially in other similar porphyry Mo deposits in NE China, the geochemical and isotopic compositions of the ore-related granite porphyry and biotite granodiorite, and the magmatic accessory minerals apatite, titanite and zircon from the Daheishan intrusions, were investigated so as to evaluate the potential roles that magma oxidation states, water contents, sulfur and metal concentrations could have played in the formation of the deposit. Magmatic apatite and titanite from the causative intrusions show similar εNd(t) values from -1.1 to 1.4, corresponding to TDM2 ages ranging from 1040 to 840 Ma, which could be accounted for by a mixing model through the interaction of mantle-derived basaltic melts with the Precambrian lower crust. The Ce and Eu anomalies of the magmatic accessory minerals have been used as proxies for magma redox state, and the results suggest that the ore-forming magmas are highly oxidized, with an estimated ΔFMQ range of + 1.8 to + 4.1 (+2.7 in average). This is also consistent with the high whole-rock Fe2O3/FeO ratios (1.3–26.4). The Daheishan intrusions display negligible Eu anomalies (Eu/Eu* = 0.7–1.1) and have relatively high Sr/Y ratios (40–94) with adakitic signatures; they also have relatively high Sr/Y ratios in apatite and titanite. These suggest that the fractionation of amphibole rather than plagioclase is dominant during the crystallization of the ore-related magmas, which further indicates a high magmatic water content (e.g., 〉5 wt%). The magmatic sulfur concentrations were calculated using available partitioning models for apatite from granitoids, and the results (9–125 ppm) are indistinguishable from other mineralized, subeconomic and barren intrusions. Furthermore, Monte Carlo modelling has been conducted to simulate the magmatic processes associated with the formation of the Daheishan Mo deposit, and the result reveals that a magma volume of ∼280 km3 with ∼10 ppm Mo was required to form the Mo ores containing 1.09 Mt Mo in Daheishan. The present study suggests that a relatively large volume of parental magmas with high oxygen fugacities and high water contents is essential for the generation of a giant porphyry Mo deposit like Daheishan, whereas a specific magma composition (e.g., with unusually high Mo and/or S concentrations), might be less critical.

Description: Background Breast cancer is the leading cause of cancer death among Hispanic women. The aim of our study was to estimate Cardiovascular disease (CVD) risk among Hispanic and non-Hispanic White (NHW) breast cancer survivors compared to their respective general population cohorts. Methods Cohorts of 17,469 breast cancer survivors (1,774 Hispanic and 15,695 NHW) in the Utah Cancer Registry diagnosed 1997–2016, and 65,866 women (6,209 Hispanic and 59,657 NHW) from the general population in the Utah Population Database were identified. Cox Proportional Hazards models were used to estimate hazard ratios (HRs) for CVD. Results The risk of diseases of the circulatory system was higher in Hispanic than NHW breast cancer survivors (HRHispanic =1.94, 99% confidence interval [CI] =1.49–2.53; H NHW =1.38, 99%CI = 1.33–1.43; P  heterogeneity=0.01) 1–5 years after cancer diagnosis, in comparison with their respective general population cohorts. Increased risks were observed for both Hispanic and NHW breast cancer survivors for diseases of the heart and the veins and lymphatics, compared to the general population cohorts. More than 5 years after cancer diagnosis, elevated risk of diseases of the veins and lymphatics persisted in both ethnicities. The CVD risk due to chemotherapy and hormone therapy was higher in Hispanic than NHW breast cancer survivors, but did not differ for distant stage, higher baseline comorbidities or baseline smoking. Conclusions We observed a risk difference for diseases of the circulatory system between Hispanic and NHW breast cancer survivors compared to their respective general population cohorts but only within the first 5 years of cancer diagnosis.

Description: Summary We report 24 palaeomagnetic directions and 10 high-quality Thellier-derived palaeointensity (PI) values, obtained from 27 sites located in Baja California Peninsula, northwestern Mexico. Sampling was done in four rock units (magnesian andesites, calc-alkaline lavas, ignimbrites, adakites) belonging to San Borja and Jaraguay monogenetic volcanic fields. These units have erupted between ∼ 15 and 2.6 Ma (previous K-Ar and 40Ar/39Ar data); hence results are presented in two consecutive periods: middle-late Miocene and Pliocene. The identified main magnetic minerals in the sampled sites are titanomagnetite, magnetite, and minor hematite, of variable grain size, present as intergrowths or surrounding grains, which reflect varying oxidation/reduction conditions during emplacement of high-temperature magmas. Based on previous geological and geophysical records, the kinematic evolution was carefully considered in the region, allowing for the independent restoration of the palaeoposition of each sampled site. Previous palaeodirections were also evaluated and corrected for tectonic motion in order to combine them with present data. Accordingly, a number of 15 and 36 directional data are used to calculate palaeopole position for Pliocene and middle-late Miocene periods, respectively, selected from a total of 74 data points. Pliocene (Plat = 87.8°, Plong = 147.5°, K = 41.06, A95 = 6.0°) and middle-late Miocene (Plat = 86.0°, Plong = 172.7°, K = 41.08, A95 = 3.8) palaeopole positions, calculated after tectonic corrections, are not statistically different from expected North American reference pole. Tectonic correction for Middle-late Miocene virtual geomagnetic poles plays an important role in reducing the resultant tilting from 2.7° to -0.8°. PI mean were calculated for Pliocene and middle-late Miocene periods at 29.2 ± 9.1 μT and 23.2 ± 6.3 μT, respectively. Compiling global filtered PI data, together with our results, indicates that the strength of the geomagnetic field during middle-late Miocene was weak (virtual dipole moment = 5.0 ± 2.2 × 1022 Am2) compared to Pliocene (6.4 ± 2.8 × 1022 Am2), and also relative to the present-day value (7.6 × 1022 Am2). This indicates the global nature of the low dipole moment during the middle-late Miocene period. However, issues related to the spatio-temporal distribution of PI data still present an obstacle to validating these suggestions; therefore, more reliable data are still needed.

Description: Summary We recompute the 26-year weekly Geocenter Motion (GCM) time series from 1994 to 2020 through the network shift approach using Satellite Laser Ranging (SLR) observations to LAGEOS1/2. Then the Singular Spectrum Analysis (SSA) is applied for the first time to separate and investigate the geophysical signals from the GCM time series. The Principal Components (PCs) of the embedded covariance matrix of SSA from the GCM time series are determined based on the w-correlation criterion and two PCs with large w-correlation are regarded as one periodic signal pair. The results indicate that the annual signal in all three coordinate components and semi-annual signal in both X and Z components are detected. The annual signal from this study agrees well in both amplitude and phase with those derived by the Astronomical Institute of the University of Bern and the Center for Space Research, especially for the Y and Z components. Besides, the other periodic signals with the periods of (1043.6, 85, 28), (570, 280, 222.7), and (14.1, 15.3) days are also quantitatively explored for the first time from the GCM time series by using SSA, interpreting the corresponding geophysical and astrodynamical sources of aliasing effects of K1/O1, T2 and Mm tides, draconitic effects, and overlapping effects of the ground-track repeatability of LAGEOS1/2.

Description: Aillikites are carbonate-rich ultramafic lamprophyres often associated with carbonatites. Despite their common field relationships, the petrogenetic links, if any, between aillikites and carbonatites remain controversial. To address this question, this study reports the results of a detailed geochemical and isotopic examination of the Permian Wajilitag aillikites in the northwestern Tarim large igneous province, including bulk-rock major-, trace-element and Sr-Nd isotope compositions, olivine major- and trace-element and (in-situ secondary ion mass spectrometry) oxygen isotope compositions, oxygen isotope data for clinopyroxene separates, and bulk-carbonate C-O isotopic analyses. Olivine in the aillikites occurs in two textural types: (i) microcrysts, 0.3-5 mm; and (ii) macrocrysts, 0.5-2.5 cm. The microcrysts exhibit well-defined linear correlations between Fo (79-89), minor and trace elements (e.g., Ni = 1304-3764 μg/g and Mn = 1363-3042 μg/g). In contrast, the olivine macrocrysts show low Fo79-81, Ni (5.3-442 μg/g) and Ca (477-1018 μg/g) and very high Mn (3418-5123 μg/g) contents, and are displaced from the compositional trend of the microcrysts. The microcrysts are phenocrysts crystallized from the host aillikite magmas. Conversely, the lack of mantle-derived xenoliths in these aillikites suggests that the macrocrysts probably represent cognate crystals (i.e., antecrysts) that formed from earlier, evolved aillikite melts. Olivine phenocrysts in the more primitive aillikite dykes (Dyke 1) have relatively higher Fo82-89 and mantle-like oxygen isotope values, whereas those in the more evolved dykes (Dyke 2 and 3) exhibit lower Fo79-86 and oxygen isotope values that trend toward lower than mantle δ18O values. The decreasing δ13C values of carbonate from Dyke 1 through to Dyke 2 and 3, coupled with the indistinguishable Sr-Nd isotopes of these dykes, suggest that the low δ18O values of olivine phenocrysts in Dyke 2 and 3 resulted from carbonate melt/fluid exsolution from a common progenitor melt. These lines of evidence combined with the overlapping emplacement ages and Sr-Nd isotope compositions of the aillikites and carbonatites in this area suggest that these exsolved carbonate melts probably contributed to the formation of the Tarim carbonatites thus supporting a close petrogenetic relationship between aillikites and carbonatites.

Description: Summary The inverse problem of finding the slowness vector from a known ray direction in general anisotropic elastic media is a challenging task, needed in many wave/ray-based methods, in particular, solving two-point ray bending problems. The conventional resolving equation set for general (triclinic) anisotropy consists of two fifth-degree polynomials and a sixth-degree polynomial, resulting in a single physical solution for quasi-compressional (qP) waves and up to 18 physical solutions for quasi-shear waves (qS). For polar anisotropy (transverse isotropy with a tilted symmetry axis), the resolving equations are formulated for the slowness vectors of the coupled qP and qSV waves (quasi-shear waves polarized in the axial symmetry plane), and independently for the decoupled pure shear waves polarized in the normal (to the axis) isotropic plane (SH). The novelty of our approach is the introduction of the geometric constraint that holds for any wave mode in polar anisotropic media: The three vectors—the slowness, ray velocity and medium symmetry axis—are coplanar. Thus, the slowness vector (to be found) can be presented as a linear combination of two unit-length vectors: the polar axis and the ray velocity directions, with two unknown scalar coefficients. The axial energy propagation is considered as a limit case. The problem is formulated as a set of two polynomial equations describing: a) the collinearity of the slowness-related Hamiltonian gradient and the ray velocity direction (third-order polynomial equation), and b) the vanishing Hamiltonian (fourth-order polynomial equation). Such a system has up to twelve real and complex-conjugate solutions, which appear in pairs of the opposite slowness directions. The common additional constraint, that the angle between the slowness and ray directions does not exceed ${90^{ m{o}}}$, cuts off one half of the solutions. We rearrange the two bivariate polynomial equations and the above-mentioned constraint as a single univariate polynomial equation of degree six for qP and qSV waves, where the unknown parameter is the phase angle between the slowness vector and the medium symmetry axis. The slowness magnitude is then computed from the quadratic Christoffel equation, with a clear separation of compressional and shear roots. The final set of slowness solutions consists of a unique real solution for qP wave and one or three real solutions for qSV (due to possible triplications). The indication for a qSV triplication is a negative discriminant of the sixth-order polynomial equation, and this discriminant is computed and analyzed directly in the ray-angle domain. The roots of the governing univariate sixth-order polynomial are computed as eigenvalues of its companion matrix. The slowness of the SH wave is obtained from a separate equation with a unique analytic solution. We first present the resolving equation using the stiffness components, and then show its equivalent forms with the well-known parameterizations: Thomsen, Alkhalifah and ‘weak-anisotropy’. For the Thomsen and Alkhalifah forms, we also consider the (essentially simplified) acoustic approximation for qP waves governed by the quartic polynomials. The proposed method is coordinate-free and can be applied directly in the global Cartesian frame. Numerical examples demonstrate the advantages of the method.

Description: This study shows the effect of climate change on the growth and survival of early life history stages of common sole (Solea solea) in different nursery areas of the North Sea, by combining a larval transport model with an individual-based growth model (Dynamic Energy Budget) to assess the fate from egg to young of the year at the end of the first growth season. Three scenarios of climate change, inspired by the 2040 Intergovernmental Panel on Climate Change projections, are tested and results are compared to a reference situation representative of current climate conditions. Under climate change scenarios where wind changes, water temperature increases and earlier spawning are considered, the early arrival of fish larvae in their nurseries results in larger young of the year at the end of summer. However, early arrival leads to higher mortality due to initially slow growth in spring. Future climate scenarios result in higher biomass and reduced first-year survival. How this result translates into changes at population level and stock management needs further investigation. Nonetheless, this study illustrates that processes linking life stages are paramount to understand and predict possible consequences of future climate conditions on population dynamics.

Description: Summary Seismic inversion is one of the most commonly used methods in the oil and gas industry for reservoir characterization from observed seismic data. Deep learning (DL) is emerging as a data-driven approach that can effectively solve the inverse problem. However, existing deep learning-based methods for seismic inversion utilize only seismic data as input, which often leads to poor stability of the inversion results. Besides, it has always been challenging to train a robust network since the real survey has limited labeled data pairs. To partially overcome these issues, we develop a neural network framework with a priori initial model constraint to perform seismic inversion. Our network uses two parts as one input for training. One is the seismic data, and the other is the subsurface background model. The labels for each input are the actual model. The proposed method is performed by log-to-log strategy. The training dataset is firstly generated based on forward modeling. The network is then pre-trained using the synthetic training dataset, which is further validated using synthetic data that has not been used in the training step. After obtaining the pre-trained network, we introduce the transfer learning strategy to fine-tune the pre-trained network using labeled data pairs from a real survey to acquire better inversion results in the real survey. The validity of the proposed framework is demonstrated using synthetic 2D data including both post-stack and pre-stack examples, as well as a real 3D post-stack seismic data set from the western Canadian sedimentary basin.

Description: Background Fanconi anemia (FA) is a rare genetic disorder associated with hematological disorders and solid tumor predisposition. Owing to phenotypic heterogeneity, some patients remain undetected until adulthood, usually following cancer diagnoses. The uneven prevalence of FA cases with different underlying FA gene mutations worldwide suggests variable genetic distribution across populations. Here, we aim to assess the genetic spectrum of FA-associated genes across populations of varying ancestries and explore potential genotype-phenotype associations in cancer. Methods Carrier frequency and variant spectrum of potentially pathogenic germline variants in 17 FA genes (excluding BRCA1/FANCS, BRCA2/FANCD1, BRIP1/FANCJ, PALB2/FANCN, RAD51C/FANCO) were evaluated in 3,523 Singaporeans and seven populations encompassing Asian, European, African and admixed ancestries from Genome Aggregation Database. Germline and somatic variants of 17 FA genes in seven cancer cohorts from The Cancer Genome Atlas (TCGA) were assessed to explore genotype-phenotype associations. Results Germline variants in FANCA were consistently more frequent in all populations. Similar trends in carrier frequency and variant spectrum were detected in Singaporeans and East Asians, both distinct from other ancestry groups particularly in the lack of recurrent variants. Our TCGA dataset exploration suggested higher germline and somatic mutation burden between FANCA and FANCC with head and neck and lung squamous cell carcinomas, as well as FANCI and SLX4/FANCP with uterine cancer, but the analysis was insufficiently powered to detect any statistical significance. Conclusion Our findings highlight the diverse genetic spectrum of FA-associated genes across populations of varying ancestries, emphasizing the need to include all known FA-related genes for accurate molecular diagnosis of FA.

Description: Edge detection is one of the most commonly used methods for the interpretation of potential field data, because it can highlight the horizontal inhomogeneous of underground geological bodies (faults, tectonic boundaries, etc.). A variety of edge detection methods have been reported in the literature, most of which are based on the combined transformation results of horizontal and vertical derivatives of the observations. Consequently, these edge detection methods are sensitive to noise. Therefore, noise reduction is desirable ahead of applying edge detection methods. However, the application of conventional filters smears discontinuities in the data to a certain extent, which would inevitably induce unfavourable influence on subsequent edge detection. To solve this problem, a novel edge-preserving smooth method for potential field data is proposed, which is based on the concept of guided filter developed for image processing. The new method substitutes each data point by a combination of a series of coefficients of linear functions. It was tested on synthetic model and real data, and the results showed that it can effectively smooth potential field data while preserving major structural and stratigraphic discontinuities. The obtained data from the new filter contain more obvious features of existing faults, which brings advantageous to further geological interpretations.

Description: The existing discontinuous Galerkin (DG) finite element method (FEM) for the numerical simulation of elastic wave propagation is primarily implemented in two dimensions. Here, a discontinuous FEM (DFEM) for efficient three-dimensional (3D) elastic wave simulation is presented. First, the velocity–stress equations of 3D elastic waves in isotropic media are transformed into first-order coefficient-changed partial differential equations. A DG discretisation method for wave field values on a unit boundary is then defined using the local Lax–Friedrichs flux format. The equations are first transformed into equivalent integral equations, and subsequently into a spatial semi-discrete ordinary differential equation system using a hierarchical orthogonal basis function. The DFEM is extended to an arbitrary high-order accuracy in the time domain using the exponential integrator technique and the explicit optimal strong-stability-preserving Runge–Kutta method. Finally, an efficient method for selecting the calculation area of the geometry of the current shot record is realised. For the computation, a multi-node parallelism with improved resource utilisation and parallelisation efficiency is implemented. The numerical results show that the proposed method can improve both the accuracy of the simulation and the efficiency of the calculation compared with existing methods.

Description: Paclitaxel (PTX) is the standard first-line treatment of ovarian cancer, but its efficacy is limited by multi-drug resistance. Therefore, it is crucial to identify effective drug targets to facilitate PTX-sensitivity for ovarian cancer treatment. Seventy PTX-administrated ovarian cancer patients were recruited in this study for gene expression and survival rate analyses. Muscleblind-like-3 (MBNL3) gain- and loss-of-function experiments were carried out in ovarian cancer cells (parental and PTX-resistant) and xenograft model. Cancer cell viability, apoptosis, spheroids formation, Nanog gene silencing were examined and conducted to dissect the underlying mechanism of MBNL3-mediated PTX-resistance. High expression of MBNL3 was positively correlated with PTX-resistance and poor prognosis of ovarian cancer. MBNL3 increased cell viability and decreased apoptosis in ovarian stem-like cells, through up-regulating Nanog. This study suggests the MBNL3-Nanog axis is a therapeutic target for the treatment of PTX-resistance in ovarian cancer management.

Description: Summary Probing seismic anisotropy of the lithosphere provides valuable clues on the fabric of rocks. We present a 3-D probabilistic model of shear wave velocity and radial anisotropy of the crust and uppermost mantle of Europe, focusing on the mountain belts of the Alps and Apennines. The model is built from Love and Rayleigh dispersion curves in the period range 5 to 149 s. Data are extracted from seismic ambient noise recorded at 1521 broadband stations, including the AlpArray network. The dispersion curves are first combined in a linearised least squares inversion to obtain 2-D maps of group velocity at each period. Love and Rayleigh maps are then jointly inverted at depth for shear wave velocity and radial anisotropy using a Bayesian Monte-Carlo scheme that accounts for the trade-off between radial anisotropy and horizontal layering. The isotropic part of our model is consistent with previous studies. However, our anisotropy maps differ from previous large scale studies that suggested the presence of significant radial anisotropy everywhere in the European crust and shallow upper mantle. We observe instead that radial anisotropy is mostly localized beneath the Apennines while most of the remaining European crust and shallow upper mantle is isotropic. We attribute this difference to trade-offs between radial anisotropy and thin (hectometric) layering in previous studies based on least-squares inversions and long period data (〉30 s). In contrast, our approach involves a massive dataset of short period measurements and a Bayesian inversion that accounts for thin layering. The positive radial anisotropy (VSH 〉 VSV) observed in the lower crust of the Apennines cannot result from thin layering. We rather attribute it to ductile horizontal flow in response to the recent and present-day extension in the region.

Description: Summary The analysis of surface wave dispersion curves is a way to infer the vertical distribution of shear-wave velocity. The range of applicability is extremely wide: going, for example, from seismological studies to geotechnical characterizations and exploration geophysics. However, the inversion of the dispersion curves is severely ill-posed and only limited efforts have been put in the development of effective regularization strategies. In particular, relatively simple smoothing regularization terms are commonly used, even when this is in contrast with the expected features of the investigated targets. To tackle this problem, stochastic approaches can be utilized, but they are too computationally expensive to be practical, at least, in case of large surveys. Instead, within a deterministic framework, we evaluate the applicability of a regularizer capable of providing reconstructions characterized by tunable levels of sparsity. This adjustable stabilizer is based on the minimum support regularization, applied before on other kinds of geophysical measurements, but never on surface wave data. We demonstrate the effectiveness of this stabilizer on: i) two benchmark—publicly available— datasets at crustal and near-surface scales; ii) an experimental dataset collected on a well-characterized site. In addition, we discuss a possible strategy for the estimation of the depth of investigation. This strategy relies on the integrated sensitivity kernel used for the inversion and calculated for each individual propagation mode. Moreover, we discuss the reliability, and possible caveats, of the direct interpretation of this particular estimation of the depth of investigation, especially in the presence of sharp boundary reconstructions.

Description: Development of new and effective anti-influenza drugs is critical for prophylaxis and treatment of influenza A virus infection. A wide range of amphibian skin secretions have been identified to show antiviral activity. Our previously reported ESC-1GN, a peptide from the skin secretion of Hylarana guentheri, displayed good antimicrobial and anti-inflammatory effects. Here, we found that ESC-1GN possessed significant antiviral effects against influenza A viruses. Moreover, ESC-1GN could inhibit the entry of divergent H5N1 and H1N1 virus strains with the IC50 values from 1.29 to 4.59 μM. Mechanism studies demonstrated that ESC-1GN disrupted membrane fusion activity of influenza A viruses by interaction with HA2 subunit. The results of site-directed mutant assay and molecular docking revealed that E105, N50 and the residues around them on HA2 subunit could form hydrogen bonds with amino acid on ESC-1GN, which were critical for ESC-1GN binding to HA2 and inhibiting the entry of influenza A viruses. Altogether, these not only suggest that ESC-1GN maybe represent a new type of excellent template designing drugs against influenza A viruses, but also it may shed light on the immune mechanism and survival strategy of H. guentheri against viral pathogens.

Description: The advance speed of a longwall face is an essential factor affecting the mining pressure and overburden movement, and an effective approach for choosing a reasonable advance speed to realise coal mine safety and efficient production is needed. To clarify the influence of advance speed on the overburden movement law of a fully mechanised longwall face, a time-space subsidence model of overburden movement is established by the continuous medium analysis method. The movement law of overburden in terms of the advance speed is obtained, and mining stress characteristics at different advance speeds are reasonably explained. The theoretical results of this model are further verified by a physical simulation experiment. The results support the following conclusions. (i) With increasing advance speed of the longwall face, the first (periodic) rupture interval of the main roof and the key stratum increase, while the subsidence of the roof, the fracture angle and the rotation angle of the roof decrease. (ii) With increasing advance speed, the roof displacement range decreases gradually, and the influence range of the advance speed on the roof subsidence is 75 m behind the longwall face. (iii) An increase in the advance speed of the longwall face from 4.89 to 15.23 m/d (daily advancing of the longwall face) results in a 3.28% increase in the impact load caused by the sliding instability of the fractured rock of the main roof and a 5.79% decrease in the additional load caused by the rotation of the main roof, ultimately resulting in a 9.63% increase in the average dynamic load coefficient of the support. The roof subsidence model based on advance speed is proposed to provide theoretical support for rational mining design and mining-pressure-control early warning for a fully mechanised longwall face.

Description: An absorbing boundary condition is necessary in seismic wave simulation for eliminating the unwanted artificial reflections from model boundaries. Existing boundary condition methods often have a trade-off between numerical accuracy and computational efficiency. We proposed a local absorbing boundary condition for frequency-domain finite-difference modelling. The proposed method benefits from exact local plane-wave solution of the acoustic wave equation along predefined directions that effectively reduces the dispersion in other directions. This method has three features: simplicity, accuracy and efficiency. Numerical simulation demonstrated that the proposed method has higher efficiency than the conventional methods such as the second-order absorbing boundary condition and the perfectly matched layer (PML) method. Meanwhile, the proposed method shared the same low-cost feature as the first-order absorbing boundary condition method.

Description: Plasma membrane tubulin is an endogenous regulator of P-ATPases and the unusual accumulation of tubulin in the erythrocyte membrane results in a partial inhibition of some their activities, causing hemorheological disorders like reduced cell deformability and osmotic resistance. These disorders are of particular interest in hypertension and diabetes, where the abnormal increase in membrane tubulin may be related to the disease development. Phosphatidylserine is more exposed on the membrane of diabetic erythrocytes than in healthy cells. In most cells, phosphatidylserine is transported from the exoplasmic to the cytoplasmic leaflet of the membrane by lipid flippases. Here we report that phosphatidylserine is more exposed in erythrocytes from both hypertensive and diabetic patients than in healthy erythrocytes, which could be attributed to the inhibition of flippase activity by tubulin. This is supported by: (i)- the translocation rate of a fluorescent phosphatidylserine analog in hypertensive and diabetic erythrocytes was slower than in healthy cells, (ii)- the pharmacological variation of membrane tubulin in erythrocytes and K562 cells was linked to changes in phosphatidylserine translocation, (iii)- the P-ATPase-dependent phosphatidylserine translocation in inside-out vesicles from human erythrocytes was inhibited by tubulin. These results suggest that tubulin regulates flippase activity and hence the membrane phospholipid asymmetry.

Description: Summary Autophagy, which is an evolutionarily conserved intracellular degradation system, involves de novo generation of autophagosomes that sequester and deliver diverse cytoplasmic materials to the lysosome for degradation. Autophagosome formation is mediated by approximately 20 core autophagy-related (Atg) proteins, which collaborate to mediate complicated membrane dynamics during autophagy. To elucidate the molecular functions of these Atg proteins in autophagosome formation, many researchers have tried to determine the structures of Atg proteins by using various structural biological methods. Although not sufficient, the basic structural catalog of all core Atg proteins was established. In this review article, we summarize structural biological studies of core Atg proteins, with an emphasis on recently unveiled structures, and describe the mechanistic breakthroughs in autophagy research that have derived from new structural information.

Description: Summary The spatial correlation of earthquake ground motion intensity can be measured from strong motion data; however, the data used in past studies is sparsely sampled in space, and only the inter-station distance was considered as a correlation variable. These limitations mean that we have only weak constraints on the true correlation structure of ground motion and that potentially important aspects of spatial correlation are unconstrained. In this study, we combine a large-N seismic array and graph analytics to explore this issue at a local scale using small local and regional earthquakes. Our result suggests site conditions, and how they interact with the incident seismic wavefield, strongly condition the spatial correlation of ground motion. Future progress in characterizing ground motion spatial variability will require dense wavefield measurements, either through nodal deployments, or perhaps distributed acoustic sensing (DAS) measurements, of seismic wavefields. Aftershock sequences of major earthquakes would provide particularly data-rich targets of opportunity.

Description: SUMMARY Mining-induced seismic events can be followed by aftershocks which increase the risk associated with the exploitation. The understanding of the aftershock generation process in induced seismicity may improve post-earthquake safety procedures applied in mines. Rudna copper ore mine in southwestern Poland commonly experiences intense and strong seismic activity accompanying the room-and-pillar exploitation of copper ore. Some strong (magnitude 〉 2) mining events are followed by numerous aftershocks and some are not followed by any. In this study we seek to find whether there is any geological, technological or seismological cause of this diversity. We study 46 strong mining events and focus on their aftershock productivity. We analyze the geological and mining setting of the studied events, their signal similarity, stress drops and the ground motion effect using data from three different seismic networks. Our results show that seismic events producing large aftershock sequences may share similar focal mechanisms and have larger ground effects than events with no aftershocks. The results also indicate the potential differences in stress drops. This interesting observation may help to better evaluate the aftershock hazard in mines. It also indicates the need for a more detailed analysis of the focal mechanisms of strong events and their relationship to the exploitation technique.

Description: Summary The present study introduces a novel method for computing post-seismic crustal internal deformation in a layered earth model. The surface dislocation Love number (DLN) calculated by the reciprocity theorem was implemented as the initial value. Furthermore, numerical integration of the value from the Earth's surface to the interior was undertaken to obtain the internal DLN. This method does not require a combination of the general solution and particular solution for the calculation of internal deformation above the seismic source, thus avoiding the loss of precision. When the post-seismic deformation within a certain period is calculated, the particular solutions at the beginning and end of the considered period cancel each other. This simplifies the calculation of post-seismic internal deformation. The numerical results depict that as the degrees increase, the post-seismic DLN reaches stability in a shorter interval of time. Thus, for improved efficiency of the post-seismic internal deformation calculation, the post-seismic DLNs should be calculated within 2000 degree and integrated with the co-seismic results. As an application, the post-seismic Coulomb failure stress changes (ΔCFS) induced by the 2011 Tohoku-Oki earthquake in the near field around the Japanese archipelagos and two major faults in Northeast China were simulated. The results exhibit that the ΔCFS values in the near field agree well with those simulated by the method in a half-space layered earth model, thus verifying the present method. The co-seismic ΔCFS on the Mishan-Dunhua fault in Northeast China, as an example, is only 0.094–0.668 KPa. However, the ΔCFS caused by the viscoelastic relaxation of the mantle within 5 years following the 2011 Tohoku-Oki event on the same fault exceeds the co-seismic results. Therefore, the cumulative effect of the viscoelastic relaxation of the mantle is deserving of attention.

Description: Summary The piezomagnetic effect is defined as a change in magnetisation with applied stress. Changes in the geomagnetic field caused by the piezomagnetic effect, referred to as the piezomagnetic field, have been theoretically estimated and compared by previous studies to interpret observed variations in the geomagnetic field. However, the piezomagnetic field estimated in previous studies may not provide an accurate estimation because they ignored spatial variations in elasticity, leading to only a rough approximation of the properties of Earth's crust. In this paper, a semi-analytical procedure for calculating the piezomagnetic field arising from a point dislocation source embedded in a layered elastic medium is derived. Following a well-established method of the vector surface harmonic expansion, all of the governing equations written in partial differential equations in a real domain, together with the linear constitutive law of the piezomagnetic effect, are converted to a set of ordinary differential equations in a wavenumber domain. Equations in the wavenumber domain are solved analytically, and each component of the piezomagnetic field in the real domain is obtained after applying the Hankel transform. By using the derived procedure, the piezomagnetic and displacement fields due to a finite fault with strike-slip, dip-slip, and tensile-opening mechanisms are estimated for media with layered elasticity structures. Results for a finite fault are obtained by integrating the point source solution over the fault plane. The results of the numerical analysis allow the effect of heterogeneities in rigidity on the piezomagnetic effect to be examined and implications for the findings of previous investigations to be drawn. In cases where the moment-release at the dislocation source is fixed, the effect of the rigidity differences between upper and lower layers on the piezomagnetic field is minor even in the case where the Curie point depth is near the source of dislocation. This result is in contrast to a previous study that assumed the Mogi model and suggested that heterogeneities in the horizontal direction may be of importance when combined with layered rigidity structures. A contrast is seen between the piezomagnetic and displacement fields corresponding to models with layered rigidity structures: the piezomagnetic field is roughly proportional to the moment-release on a source fault, whereas the displacement field is proportional to slip or opening of the fault. Provided that the rigidity of the crust increases with increasing depth, the calculated piezomagnetic field is likely to have been underestimated in many earlier studies, which assumed uniform rigidity and a geodetically inverted size of slip.

Description: Summary Unravelling relations between lateral variations of mid-crustal seismicity and the geometry of the Main Himalayan Thrust system at depth is a key issue in seismotectonic studies of the Himalayan range. These relations can reveal along strike changes in the behavior of the fault at depth related to fluids or the local ramp-flat geometry and more generally of the stress build-up along the fault. Some of these variations may control the rupture extension of intermediate, large or great earthquakes, the last of which dates back from 1505 CE in far western Nepal. The region is also associated to lateral spatio-temporal variations of the mid-crustal seismicity monitored by the Regional Seismic Network of Surkhet-Birendranagar. This network was supplemented between 2014 and 2016 by 15 temporary stations deployed above the main seismic clusters giving new potential to regional studies. Both absolute and relative locations together with focal mechanisms are determined to gain insight on the fault behavior at depth. We find more than 4000 earthquakes within 5 and 20 km-depth clustered in three belts parallel to the front of the Himalayan range. Finest locations reveal close relationships between seismic clusters and fault segments at depth among which mid-crustal ramps and reactivated tectonic slivers. Our results support a geometry of the Main Himalayan Thrust involving several fault patches at depth separated by ramps and tear faults. This geometry most probably affects the pattern of the coseismic ruptures breaking partially or totally the locked fault zone as well as eventual along strike variations of seismic coupling during interseismic period.

Description: Summary Crustal deformation caused by hydrological processes has long been detected using space geodetic techniques, yet questions remain about the relative contributions of surface water and groundwater to the geodetic signals in different regions. Here, we investigate forward models of elastic loading deformation caused by a variety of water-storage changes within the Great Lakes region, including fluctuations in lake-water volume, soil moisture, and snow load. We use lake-level data from the Great Lakes Environmental Research Laboratory, soil-moisture content from the North American Land Data Assimilation System (NLDAS), snow load from the Snow Data Assimilation System (SNODAS), and background hydrological load at the global scale from Gravity Recovery and Climate Experiment (GRACE). We compare the modeled surface deformation with estimates of hydrological loading deformation inferred from Global Navigation Satellite System (GNSS) measurements. We find that seasonal deformation measured by GNSS is dominated by regional-scale hydrological loading based on strong correlations with the modeled loading displacements. The mean correlation coefficient for the study network is 0.56. The correlation coefficients vary spatially within the study region and exceed 0.9 at some stations near to the Great Lakes. We assess the relative contribution of each individual hydrological component to the total integrated hydrological load. We find that soil moisture consistently explains the largest percentage (27 per cent-69 per cent) of the total vertical loading deformation for 87 per cent of GNSS stations in the Great Lakes region. Snow loading and soil moisture contribute relatively equally in the northern reaches of the study area (e.g. Canadian shield, northern Superior basin). Lake loading accounts for about 10–25 per cent of the total loading signal in the immediate vicinity of the lakes. We also investigate the sensitivities of the surface loading displacements to three different Earth models, including two with lateral variations in structure. The structural variations considered here have limited impact (

Description: The slab beneath the Alboran Sea is a consequence of the collision between two continents (Europe and Africa), which was initiated along the northeastern Spanish coast, experienced slab rollback and migrated to the area adjacent to the two continents. The tectonic background in this area includes episodes of collisions with adjacent continents as well as extension of those basins in the western Mediterranean. Here, we present three-dimensional (3D) Kirchhoff-approximate generalized Radon transform (GRT) images to further constrain the lithospheric structures previously identified by other researchers. The GRT images were calculated from the same P-to-S (Pds or Ps) teleseismic receiver functions (RFs) as the previous common conversion point (CCP) stacking, but the GRT data provide figures with greater resolution than the Pds RFs CCP results. This study indicates that the Alboran Slab may have completely detached from the crustal base under the western Betics Mountains and that a larger range of lithospheric ‘peeling off’ developed beneath the western part of the Betics Mountains than some previous results have claimed. The observed thin lithosphere under the Middle Atlas (MA) and eastern High Atlas (HA) may have a geodynamic relationship with lithospheric delamination under the eastern part of the Rif Mountains, which has also led to the thin lithosphere under the eastern Rif. According to the thick lithosphere under the western HA, the shallow LAB under the MA and eastern HA may have no heat-flow connection with the Canary mantle plume, as stated in several previous studies.

Description: Summary Convection in the liquid outer core of the Earth is driven by thermal and chemical perturbations. The main purpose of this study is to examine the impact of double-diffusive convection on magnetic field generation by means of three-dimensional global geodynamo models, in the so-called “top-heavy” regime of double-diffusive convection, when both thermal and compositional background gradients are destabilizing. Using a linear eigensolver, we begin by confirming that, compared to the standard single-diffusive configuration, the onset of convection is facilitated by the addition of a second buoyancy source. We next carry out a systematic parameter survey by performing 79 numerical dynamo simulations. We show that a good agreement between simulated magnetic fields and the geomagnetic field can be attained for any partitioning of the convective input power between its thermal and chemical components. On the contrary, the transition between dipole-dominated and multipolar dynamos is found to strongly depend on the nature of the buoyancy forcing. Classical parameters expected to govern this transition, such as the local Rossby number -a proxy of the ratio of inertial to Coriolis forces- or the degree of equatorial symmetry of the flow, fail to capture the dipole breakdown. A scale-dependent analysis of the force balance instead reveals that the transition occurs when the ratio of inertial to Lorentz forces at the dominant length scale reaches 0.5, regardless of the partitioning of the buoyancy power. The ratio of integrated kinetic to magnetic energy Ek/Em provides a reasonable proxy of this force ratio. Given that Ek/Em ≈ 10−4 − 10−3 in the Earth’s core, the geodynamo is expected to operate far from the dipole-multipole transition. It hence appears that the occurrence of geomagnetic reversals is unlikely related to dramatic and punctual changes of the amplitude of inertial forces in the Earth’s core, and that another mechanism must be sought.

Description: Summary The Ordos Block is located at the intersection of the Tibetan Plateau, the South China Plate, and the North China Craton. The deep deformation of its surrounding areas is geologically complicated. Seismic anisotropy provide information about past and present deformation of the upper mantle and help to better understand deep deformation processes. We obtained the anisotropic pattern at high resolution within and surrounding the Ordos Block by analyzing teleseismic data from ∼710 newly deployed temporary seismic stations based on SKS phases from ∼86 earthquake. The central and eastern Ordos Block with a relatively thick and rigid lithosphere is characterized by a weak anisotropy. In the western part of the Ordos Block, the fast-wave polarization direction is dominantly NW–SE. We believe the lithosphere in the western part of the Ordos Block may have undergone significant deformation caused by expansion and compression of the Tibetan Plateau. Near the Datong Basin, the delay time is 0.92 s and the fast-wave polarization direction is mainly oriented NW–SE, perpendicular to the NE-directed compression of the Tibetan Plateau and parallel to the basin extension direction. We speculate that this anisotropy is related to the long-range effect of NE compression of the northeastern Tibetan Plateau on the low-velocity upper mantle in this area. The weak anisotropy in the central part of the Shanxi Rift indicates that the thickness and mechanical strength of the high-velocity lithosphere are higher than in the southern and northern regions.

Description: An influential leader in the seismological community, Lay was awarded this year's geophysics Gold Medal for his outstanding work in seismological analysis

Description: Summary Correlation of the coda of Empirical Green's functions from ambient noise can be used to reconstruct Empirical Green's function between two seismic stations deployed different periods of time. However, such method requires a number of source stations deployed in the area surrounding a pair of asynchronous stations, which limit its applicability in cases where there are not so many available source stations. Here, we propose an alternative method, called two-station C2 method, which uses one single station as a virtual source to retrieve surface wave phase velocities between a pair of asynchronous stations. Using ambient noise data from USArray as an example, we obtain the interstation C2 functions using our C2 method and the traditional cross-correlation functions (C1 functions). We compare the differences between the C1 and C2 functions in waveforms, dispersion measurements, and phase velocity maps. Our results show that our C2 method can obtain reliable interstation phase velocity measurements, which can be used in tomography to obtain reliable phase velocity maps. Our method can significantly improve ray path coverage from asynchronous seismic arrays and enhance the resolution in ambient noise tomography for areas between asynchronous seismic arrays.

Description: Summary We calculate and analyse the coordinate time series of 282 permanent GPS stations located in Greece and 47 in surrounding countries. The studied period is 2000–2020. The average GPS time series length is 6.5 years. The formal velocity uncertainties are rescaled to be consistent with the velocity scatters measured at 110 pairs of stations separated by less 15 km. We remove the effect of the crustal earthquakes of Mw ≥ 5.3. We quantify and model the postseismic deformations. Two relaxation times are usually needed, one short of some weeks, one long of one year or more. For the large Mw = 6.9 events of Samothraki 2014 and Methoni 2008, the postseismic deformation equals or exceeds the coseismic one. We detect at three stations a deformation transient in May 2018 that may correspond to a slow earthquake beneath Zakynthos and north-west Peloponnese, with equivalent magnitude 5.8. The density and accuracy of the velocities make it possible to better quantify several characteristics of the deformation in the Aegean, in particular: (a) the transition from the Anatolian domain, located in the south-east, to the European domain through the western end of the North Anatolian fault; (b) the north-south extension in the western Aegean; (c) the east-west extension of the western Peloponnese; (d) the clockwise rotation of the Pindos; (e) the north-south extension in central Macedonia. Large parts of the central Aegean, eastern Peloponnese and western Crete form a wide stable domain with internal deformation below 2 nstrain yr−1. We build a kinematic model comprising ten crustal blocks corresponding to areas where the velocities present homogeneous gradients. The block boundaries are set to fit with known localized deformation zones, e.g. the rift of Corinth, the North Anatolian fault, the Katouna fault. When the velocities steps are clear but not localized, e.g. through the Peloponnese, the boundary line is arbitrary and represents the transition zone. The model fits the velocities with a root mean square deviation of ± 0.9 mm yr−1. At the boundaries between blocks we compare the predicted and observed deformations. We find shear rates of 7.4 and 9.0 mm yr−1 along the Movri and Katouna faults, 14.9 and 8.7 mm yr−1 along the North Anatolian fault near Lemnos and near Skopelos respectively, extension of 7.6, 1.5 and 12.6 mm yr−1 across the Gulf of Patras, the Trichonis Lake and the Ambracian Gulf. The compression across western Epirus is 3.7 mm yr−1. There is a dextral transtensional movement of 4.5 mm yr−1 between the Amorgos and Astypalea islands. Only the Ionian Islands region shows evidence of coupling along the subduction interface.

Description: SUMMARY Ekman layers develop at the boundaries of the Earth’s fluid core in response to precession. Instabilities in these layers lead to turbulence when a local Reynolds number, Re, based on the thickness of the Ekman layer, exceeds a critical value. The transition to turbulence is often assessed using experiments for steady Ekman layers, where the interior geostrophic flow is independent of time. Precessionally driven flow varies on diurnal timescales, so the transition to turbulence may occur at a different value of Re. We use 3-D numerical calculations in a local Cartesian geometry to assess the transition to turbulence in precessional flow. Calculations retain the horizontal component of the rotation vector and account for the influence of fluid stratification. The transition to turbulence in a neutrally stratified fluid occurs near Re = 500, which is higher than the value Re = 150 usually cited for steady Ekman layers. However, it is comparable to the nominal value for precessional flow in the Earth. Complications due to fluid stratification or a magnetic field can suppress the transition to turbulence, reducing the likelihood of turbulent Ekman layers in the Earth’s core.

Description: SUMMARY An underground nuclear explosion (UNE) couples mechanical energy into crustal rock, which propagates as seismic and acoustic waves. These different physical phenomena transport, by different pathways, to standoff detectors at varying distances. The transport pathways attenuate the original signal but in different ways. Enabled by correct statistical weighting, signal attenuation models can be used to combine these disparate sensor data to estimate the yield of an UNE. Contemporaneous statistical models, used in yield estimation, can be improved with an advanced partition of error for these physical signal propagation models. We present an advanced multivariate approach to error modelling of multiphenomenology physical signatures. In addition to measurement error, our error model represents physical model biases as random with a physics-based covariance structure. To illustrate this proposed framework, we demonstrate the estimation of explosion yield using openly available seismic and acoustic data from chemical single-point explosions.

Description: SUMMARY Following the installation of a temporary seismological network in western Greece north of the Gulf of Patras, we determined the quality of the sites of each of the 10 stations in the network. For this, we used the horizontal-to-vertical spectral ratio (HVSR) method and calculated an average curve over randomly selected days between 0 and 10 Hz. The daily HVSR curve is determined by the HVSR 12-hr calculation (1 hr every two) without distinction between seismic ambient noise and earthquake signal. The HVSR curves obtained can be classified in three categories: flat curves without amplification, curves with a amplification peaks covering a large frequency range, and curves with one or more narrow peaks. In this third category C3, one station has one peak, two have two and one has three. On the contrary of what it is commonly assumed, the amplitudes and the resonance frequencies of these narrow peaks are not stable over time in C3. We determined the maximum of the amplitude of each peak with the corresponding central frequency for each day during 2.5 yr. Except for the station with three peaks, which finally appears stable within the uncertainties, the principal peak exhibits a seasonal variation, with a maximum in winter and a minimum in summer, the observations being more dispersed during winter. The second peak, when it exists, varies in the same way except at one station where it varies oppositely. These variations are clearly correlated with the loading and unloading cycle of the underlying aquifers as shown by the comparison with water level and yield measurements from wells located close to the stations. Moreover, they are also correlated with the vertical surface displacements observed at continuously recording GPS stations. The dispersion of the observed maximum amplitude in winter is probably related to the rainfall and the soil moisture modifying the S-wave velocity as revealed by other studies. From this study, we would like to emphasize that the use the HVSR method to constrain the S-wave velocity and the thickness of the sediment layer over the bedrock in the basin, has to be done with caution. Upon further confirmation of its robustness, the HVSR methodology presented here could be a good and easy-to-use tool for a qualitative survey of the aquifer backdrop and its seasonal behaviour, and of the soil moisture conditions.

Description: Summary Squirt flow is an essential cause of wave dispersion and attenuation in saturated rocks. The squirt flow model, proposed by Gurevich et al. (2010), has been widely applied to explain the wave dispersion and associated attenuation for saturated rocks at sonic and seismic frequency bands. In this model, the saturated bulk modulus is obtained by taking the partially relaxed frame bulk modulus as the dry frame modulus into Gassmann's formula with the mineral bulk modulus as the matrix bulk modulus. However, because of the weakening effect of soft pores on rock matrix bulk modulus, the model cannot accurately predict the saturated bulk modulus when the soft-pore fraction (the ratio of the soft porosity to total porosity) becomes large. We modified this model following Gurevich et al. (2010) by setting a different boundary condition. The modified squirt flow model can obtain correct saturated bulk modulus for large soft-pore fractions in the full range of frequencies, showing excellent consistency with the predictions of Gassmann and Mavko & Jizba (modified) at both low- and high-frequency limits, respectively. Modeling results show that the saturated bulk moduli and their dispersions calculated by the original and modified models exhibit little difference when the soft-pore fraction is small. Under this condition, the original model is as effective and accurate as the modified one. When the soft-pore fraction becomes larger, the differences in the bulk moduli and their dispersions become substantial, suggesting the original model is not applicable any longer. Furthermore, the differences calculated for the intermediate frequency range is even more obvious than other ranges, suggesting that the modified model should be used to calculate the bulk modulus and the dispersion in this frequency range. In summary, the modified squirt flow model can extend the original model's applicable range in terms of soft-pore fraction and has a potential application in rocks having a relatively large amount of soft-pore fraction such as basalts.

Description: Summary The noise attenuation is a fundamental step in seismic data processing, especially when ground-roll suppression remains a challenge. Rank-reduction methods have become quite popular in recent decades, as they promote significant improvements in the quality of data, highlighting reflections in seismograms. We present a methodology for ground-roll filtering, which combines the application of a recursive-iterative Singular Spectrum Analysis method, in the time-domain, as a particular way to decompose seismic data, with the computation of the average instantaneous frequency of the signal components. This combination allows for a precise estimation and filtering of the ground-roll noise. The frequency values are used for determining, in each component, the low-frequency parts associated with the ground-roll. For every single component, the ground-roll is attenuated by zeroing, and stacking the data-components, where the average instantaneous frequency values match the ground-roll bandwidth of frequency. Also, in order to enhance the lateral coherence of the reflectors, we present an extension of the recursive-iterative algorithm for a multichannel case. The multichannel algorithm is applicable on a shot, or common mid-point family of seismic traces, after the normal move-out correction. The numerical results using real data show the effectiveness of the proposed methodology for ground-roll attenuation and for improving the velocity analysis.

Description: Primary cilia are evolutionarily conserved microtubule-based organelles that protrude from the surface of almost all cell types and decode a variety of extracellular stimuli. Ciliary dysfunction causes human diseases named ciliopathies, which span a wide range of symptoms, such as developmental and sensory abnormalities. The assembly, disassembly, maintenance, and function of cilia rely on protein transport systems including intraflagellar transport (IFT) and lipidated protein intraflagellar targeting (LIFT). IFT is coordinated by three multisubunit protein complexes with molecular motors along the ciliary axoneme, while LIFT is mediated by specific chaperones that directly recognize lipid chains. Recently, it has become clear that several post-translational modification enzymes play crucial roles in the regulation of IFT and LIFT. Here we review our current understanding of the roles of these post-translational modification enzymes in the regulation of ciliary protein trafficking as well as their regulatory mechanisms, physiological significance, and involvement in human diseases.

Description: Background Prior research suggests a relationship between overall diet quality and breast cancer survival, though few studies have reported on this topic. We evaluated whether four dietary quality indices consistent with healthy eating recommendations around the time of breast cancer diagnosis were associated with risk of recurrence, cause-specific and all-cause mortality. Methods A total of 3,660 women diagnosed with invasive breast cancer were included. Diet was assessed an average of 2.3 (range = 0.7–18.7) months after diagnosis, from which four dietary quality indices were derived: the American Cancer Society guidelines (ACS), the alternate Mediterranean Diet Index (aMED), the Dietary Approaches to Stop Hypertension (DASH) and the 2015 Healthy Eating Index (HEI). Over 40,888 person-years of follow-up, 461 breast cancer recurrences and 655 deaths were ascertained. Cox models were used to estimate hazards ratios (HRs) and 95% confidence intervals (CIs). Results Adjusted comparisons between extreme quintiles showed all four dietary quality indices to be inversely associated with all-cause mortality, suggesting a 21%–27% lower risk (ACS HR = 0.73 [95%CI = 0.56–0.95], aMED HR = 0.79 [95%CI = 0.61–1.03], DASH HR = 0.76 [95%CI = 0.58–1.00], HEI HR = 0.77 [95%CI = 0.60–1.01]). Similar patterns were noted for non-breast cancer mortality (ACS HR = 0.69 [95%CI = 0.48–0.98], aMED HR = 0.73 [95%CI = 0.50–1.05], DASH HR = 0.55 [95%CI = 0.38–0.79], HEI HR = 0.67 [95%CI = 0.48–0.94]). None of the dietary quality indices were associated with recurrence or breast cancer-specific mortality. Conclusion Food intake patterns concordant with dietary quality indices consistent with recommendations for healthy eating may be beneficial for women with breast cancer.

Description: SUMMARY The costly power requirements of delivering seismic data back to Earth from planetary missions requires the development of algorithms for lander-side signal analysis for telemetry prioritization. This is difficult to explicitly program, especially if no prior seismic data are available from the planetary body. Deep learning computer vision has been used to generalize seismic signals on Earth for earthquake early warning problems but such techniques have not yet been expanded to planetary science. We demonstrate that Convolutional Neural Networks can be used to accurately catalogue planetary seismicity without local training data by building binary noise/signal classifiers from a single Earth seismic station and applying the models to moonquakes from the Apollo Passive Seismic Experiment (PSE) and the Lunar Seismic Profiling Experiment (LSPE). In order to promote generality and reduce the amount of training data, the algorithms use spectral images instead of time-series. Two- to five-layer convolution models are tested against a subset of 200 Grade-A events from the PSE and obtained station accuracy averages of 89–96 per cent. As the model was applied to an hour trace of data (30 min before and after the Grade-A event), additional detections besides the Grade-A event are unavoidable. In order to comprehensively address algorithm accuracy, additional seismic detections corresponding to valid signals such as other moonquakes or multiples within a particularly long event needed to be compared with those caused by algorithm error or instrument glitches. We developed an ‘extra-arrival accuracy’ metric to quantify how many of the additional detections were due to valid seismic events and used it to select the three-layer model as the best fit. The three-layer model was applied to the entire LSPE record and matched the lunar day–night cycle driving thermal moonquake generation with fewer false detections than a recent study using Hidden Markov Models. We anticipate that these methods for lander-side signal detection can be easily expanded to non-seismological data and may provide even stronger results when supplemented with synthetic training data.

Description: SUMMARY The challenge of ruling out potential rupture nodal planes with opposite dip orientations during interferometric synthetic aperture radar (InSAR)-based kinematic inversions has been widely reported. Typically, slip on two or more different fault planes can match the surface deformation measurements equally well. The ambiguous choice of the nodal plane for the InSAR-based models was thought to be caused by InSAR's 1-D measurement and polar orbiting direction, leading to its poor sensitivity to north–south crustal motion. Through synthetic experiments and simulations, this paper quantitatively demonstrates the main reason of the ambiguous InSAR-based models, which confuse researchers in the small-to-moderate thrust earthquake cases investigation. We propose the inherent 1-D measurement is not the principle cause of the fault plane ambiguity, since models derived from the same InSAR data predict similar, but not identical, 3-D deformation patterns. They key to differentiating between these different models is to be able to resolve the small asymmetry in the surface deformation pattern, which may be smaller in amplitude than the typical noise levels in InSAR measurements. We investigate the fault geometry resolvability when using InSAR data with different noise levels through ‘R’ value. We find that the resolvability does not only rely on the InSAR noise, but also on the fault geometry itself (i.e. depth, dips angle and strike). Our result shows that it is impossible to uniquely determine the dip orientation of thrust earthquakes with Mw  5.0 km with InSAR data at a noise level that is typical for mountain belts. This inference is independent from the specific data set (i.e. interferogram or time-series) and allows one to assess if one can expect to be able to resolve the correct fault plane at all.

Description: Death receptors, members of the tumor necrosis factor receptor (TNFR) superfamily, are characterized by the presence of a death domain in the cytosolic region. TNFR1, Fas, and TNF-related apoptosis-inducing ligand receptors, which are prototypical death receptors, exert pleiotropic functions in cell death, inflammation, and immune surveillance. Hence, they are involved in several human diseases. The activation of death receptors and downstream intracellular signaling are regulated by various post-translational modifications, such as phosphorylation, ubiquitination, and glycosylation. Glycosylation is one of the most abundant and versatile modifications to proteins and lipids, and it plays a critical role in the development and physiology of organisms, as well as the pathology of many human diseases. Glycans control a number of cellular events, such as receptor activation, signal transduction, endocytosis, cell recognition, and cell adhesion. It has been demonstrated that oligo- and monosaccharides modify death receptors and intracellular signaling proteins, and regulate their functions. Here, we review the current understanding of glycan modifications of death receptor signaling and their impact on signaling activity.

Description: Background After resection of colorectal cancer liver metastases (CRLM) two main histopathological growth patterns can be observed; a desmoplastic and a non-desmoplastic subtype. The desmoplastic subtype has been associated with superior survival. These findings require external validation. Methods An international multicenter retrospective cohort study was conducted in patients treated surgically for CRLM at three tertiary hospitals in the US and the Netherlands. Determination of histopathological growth patterns was performed on hematoxylin & eosin stained sections of resected CRLM according to international guidelines. Patients displaying a desmoplastic histopathological phenotype (only desmoplastic growth observed) were compared to patients with a non-desmoplastic phenotype (any non-desmoplastic growth observed). Cut-off analyses on the extent of non-desmoplastic growth were performed. Overall (OS) and disease-free (DFS) survival were estimated using Kaplan-Meier and multivariable Cox analysis. All statistical tests were 2-sided. Results In total 780 patients were eligible. A desmoplastic phenotype was observed in 19.1% and was associated with microsatellite instability (14.6% versus 3.6%, p = .01). Desmoplastic patients had superior 5-year OS (73.4% [95% CI = 64.1–84.0] versus 44.2% [95% CI = 38.9–50.2], p 

Description: Summary Secondary microseisms are ubiquitous ambient noise vibrations due to ocean activity, dominating worldwide seismographic records at seismic periods between 3 and 10 s. Their origin is a heterogeneous distribution of pressure fluctuations along the ocean surface. In spherically symmetric Earth models, no Love surface waves are generated by such a distributed surface source. We present global-scale modeling of three-component secondary microseisms using a spectral-element method, which naturally accounts for a realistic distribution of surface sources, topography and bathymetry, and three-dimensional (3D) heterogeneity in Earth’s crust and mantle. Seismic Love waves emerge naturally once the system reaches steady state. The ergodic origin of Love waves allows us to model the horizontal components of secondary microseisms for the first time. Love waves mostly originate from the interaction of the seismic wavefield with heterogeneous earth structure, in which the mantle plays an important role despite the short periods involved. Bathymetry beneath the source region produces weak horizontal forces that are responsible for a weak and diffuse Love wavefield. The effect of the bathymetric force splitting in radial and horizontal components is overall negligible when compared to the effect of 3D heterogeneity. However, we observe small and well-focused Love-wave arrivals at seismographic stations in Europe due to force splitting at the steepest portion of the North Atlantic Ridge and the ocean-continent boundary. The location of the sources of Love waves is seasonal at periods shorter than about 7 s, while seasonality is lost at the longer periods. Sources of Rayleigh and Love waves due to the same storm may be located very far away, indicating that energy equipartitioning might not hold in the secondary microseism period band.

Description: Background Duloxetine effectively treats aromatase inhibitor–associated musculoskeletal symptoms (AIMSS) in women with breast cancer but causes low-grade toxicities. This secondary analysis examines the relationship between adverse events (AE) and patient-perceived benefit, based on patient self-report that the treatment received was beneficial despite side effects. We hypothesized that duloxetine had a favorable effect on patient-perceived benefit, even among duloxetine-treated patients who experienced AEs and who, had they been treated with placebo, would have experienced none. Methods Principal stratification was used to estimate the effect of duloxetine versus placebo on patient-perceived benefit and FACT-ES functional quality of life (FQOL) in the randomized, double-blind trial SWOG S1202 (n = 289). Subgroups of patients were defined by observed and counterfactual (what would have occurred had they been randomized to the opposite study arm) experiences of AEs and the original primary outcome, reduction of average pain after 12 weeks of ≥ 2 points on the Brief Pain Inventory–Short Form. Results Duloxetine caused an estimated 23.4% (95% credible interval [CI] = 13.4% to 33.7%) of patients to experience an AE even though they would have experienced none on placebo. Those patients remained more likely to report that their received treatment was beneficial than comparable patients assigned placebo (73.3% vs 41.8%, respectively, 95%CI for difference = 15.4 to 47.2 percentage points), though there was no statistically significant effect of duloxetine on FQOL (11.3 vs 9.0, 95%CI for difference = -2.2 to + 6.7). Conclusion Duloxetine resulted in higher patient-perceived benefit, even among those who would have an AE on duloxetine but none on placebo. Treatment of AIMSS with duloxetine should be considered for appropriate patients.

Description: Summary The seismic velocity of the oceanic crust is a function of its physical properties that include its lithology, degree of alteration, and porosity. Variations in these properties are particularly significant in young crust, but also occur with age as it evolves through hydrothermal circulation and is progressively covered with sediment. While such variation may be investigated through P-wave velocity alone, joint analysis with S-wave velocity allows the determination of Poisson's ratio, which provides a more robust insight into the nature of change in these properties. Here we describe the independent modelling of P- and S-wave seismic datasets, acquired along an ∼330 km-long profile traversing new to ∼8 Myr-old oceanic crust formed at the intermediate-spreading Costa Rica Rift (CRR). Despite S-wave data coverage being almost four-times lower than that of the P-wave dataset, both velocity models demonstrate correlations in local variability and a long-wavelength increase in velocity with distance, and thus age, from the ridge axis of up to 0.8 and 0.6 km s−1, respectively. Using the Vp and Vs models to calculate Poisson's ratio (σ), it reveals a typical structure for young oceanic crust, with generally high values in the uppermost crust that decrease to a minimum of 0.24 by 1.0–1.5 km sub-basement, before increasing again throughout the lower crust. The observed upper crustal decrease in σ most likely results from sealing of fractures, which is supported by observations of a significant decrease in porosity with depth (from ∼15 to 

Description: Summary Previous studies have demonstrated that finite-fault simulations of actual or hypothetical earthquakes using deterministic, physics-based simulation techniques constitute an effective tool for characterizing near-fault ground strains and rotations in the low-frequency range. The characteristics of these motions are further investigated in this study by performing forward ground-motion simulations of three well-documented strike-slip earthquakes (i.e. 2004 Mw 6.0 Parkfield, 1979 Mw 6.5 Imperial Valley, 1999 Mw 7.5 Izmit) using models of the seismic source and crustal structure available in the literature. Time histories of ground strains and rotations are numerically generated at near-fault stations and at a dense grid of observation points extending over the causative fault. This is achieved by finite differencing translational motions simulated at very closely spaced stations using a kinematic modeling approach. The simulation results show that the three strike-slip earthquakes produce large-amplitude pulse-like shear strain and torsion in the forward direction of rupture propagation. The time histories of specific components of displacement gradient, strain, and rotation at near-fault stations can be estimated from those of ground velocities using a phase velocity, whereas peak ground torsions in the near-fault region can be reasonably estimated from peak horizontal ground velocities using a scaling factor. However, both the phase velocity and the scaling factor exhibit significant variability in the near-fault region of the considered earthquakes. The concept of isochrones is also utilized to associate fault rupture characteristics with near-fault ground strains and rotations. The results indicate that the seismic energy radiated from the high-isochrone-velocity region of the fault—which encompasses areas of large slip locally driven by high stress drop—arrives at a near-fault station in a short time interval that coincides with the time window of the large-amplitude pulse-like shear strain and torsion.

Description: Stable carbon and hydrogen isotope technology is used in determining gas sources in coal mines. Coal measures at the Shuangliu mine mainly contain nine coal seams (i.e. No. 2 to No. 10) and five limestone layers (namely, L1 to L5). The coal seams are interbedded with the limestone layers. A large amount of methane is adsorbed in the limestone layer, and the actual measured maximum gas pressure is 1.3 MPa, posing a serious gas emission safety risk in roadway excavation in the coal measures. In order to effectively manage the safety risk of gas emissions, it is necessary to determine gas sources and take necessary control measures. In this study, 50 gas samples were taken from the coal seams and 10 gas samples were collected from the limestone layers. These samples were measured for their composition and stable carbon and hydrogen isotopes. Stable carbon and hydrogen isotope tracer separation technique and multi-source linear calculation methods were used to analyze the measurement results. The study shows that 84% of gas in the L1, L2 and L3 limestone layers comes from the No. 8 coal seam and 11% from the No. 9 coal seam; gas in the L4 limestone layer is mainly from the No. 8 (44%), No. 7 (37%) and No. 6 coal seams (16%), and gas in L5 limestone layer mainly comes from the No. 6 (59%), No. 7 (23%) and No. 8 coal seams (13%). The research results can guide the design of gas drainage boreholes before roadway tunneling, so it has important guiding significance in the formulation of comprehensive gas control schemes.

Description: Summary Elongate inclusions immersed in a viscous fluid generally rotate at a rate that is different from the local angular velocity of the flow. Often, a net alignment of the inclusions develops, and the resulting shape preferred orientation (SPO) of the particle ensemble can then be used as a strain marker that allows reconstruction of the fluid’s velocity field. Much of the previous work on the dynamics of flow-induced particle rotations has focused on spatially homogeneous flows with large-scale tectonic deformations as the main application. Recently, the theory has been extended to spatially varying flows, such as magma with embedded crystals moving through a volcanic plumbing system. Additionally, an evolution equation has been introduced for the probability density function (PDF) of crystal orientations. Here, we apply this new theory to a number of simple, two-dimensional flow geometries commonly encountered in magmatic intrusions, such as flow from a dyke into a reservoir or from a reservoir into a dyke, flow inside an inflating or deflating reservoir, flow in a dyke with a sharp bend, and thermal convection in a magma chamber. The main purpose is to provide a guide for interpreting field observations and for setting up more complex flow models with embedded crystals. As a general rule, we find that a larger aspect ratio of the embedded crystals causes a more coherent alignment of the crystals, while it has only a minor effect on the geometry of the alignment pattern. Due to various perturbations in the crystal rotation equations that are expected in natural systems, we show that the time-periodic behavior found in idealized systems is probably short-lived in nature, and the crystal alignment is well described by the time-averaged solution. We also confirm some earlier findings. For example, near channel walls, fluid flow often follows the bounding surface and the resulting simple shear flow causes preferred crystal orientations that are approximately parallel to the boundary. Where pure shear deformation dominates, there is a tendency for crystals to orient themselves in the direction of the greatest tensile strain rate. Where flow impinges on a boundary, for example in an inflating magma chamber or as part of a thermal convection pattern, the stretching component of pure shear aligns with the boundary, and the crystals orient themselves in that direction. In the field, this local pattern may be difficult to distinguish from a boundary-parallel simple shear flow. Pure shear also dominates along the walls of a deflating magma chamber and in places where the flow turns away from the reservoir walls, but in these locations, the preferred crystal orientation is perpendicular to the wall. Overall, we find that our calculated patterns of crystal orientations agree well with results from analogue experiments where similar geometries are available.

Description: The role of subducting oceanic crust-derived fluids in generating mafic arc magmatism has been widely documented. However, the subducting oceanic crust is generally composed of basaltic igneous crust and seafloor sediment, which may give rise to different compositions of liquid phases causing metasomatism of the mantle wedge. Because of the similarity in enrichment of fluid-mobile incompatible elements in the two sources of subduction zone fluids, it has been a challenge to distinguish between them when studying the products of mafic arc magmatism. This difficulty is overcome by a combined study of whole-rock Li isotopes and zircon O isotopes in addition to whole-rock major-trace elements and Sr-Nd-Hf isotopes in Late Paleozoic mafic igneous rocks from southwestern Tianshan in western China. Zircon U-Pb dating yields consistent ages of 313±3 Ma to 305±1 Ma for magma crystallization. The mafic igneous rocks exhibit arc-like trace element distribution patterns and depleted whole-rock Nd-Hf isotopes but slightly high (87Sr/86Sr)i ratios of 0.7039 to 0.7056. They also show positive zircon εHf(t) values and slightly higher zircon δ18O values of 5.2-7.6‰. There are covariations of whole-rock Sr isotopes with Th/La and Rb/Nb ratios, indicating a contribution from terrigenous sediment-derived fluids to their mantle source in addition to basaltic igneous crust-derived fluids. Based on the slightly higher zircon δ18O values but variably lower whole-rock δ7Li values of -0.8 to 3.5‰ for the target rocks than those of mantle respectively, both altered oceanic basalt- and terrigenous sediment-derived fluids are identified in the mantle source of these mafic igneous rocks. Model calculations for trace elements and Sr-Nd-Li isotopes further confirm that the geochemical compositions of these mafic igneous rocks can be explained by chemical reaction of depleted MORB mantle peridotite with the mixed fluids to generate ultramafic metasomatites at subarc depths. Therefore, chemical metasomatism of the mantle wedge is a key mechanism for the incorporation of crustal components into the source of arc-like mafic igneous rocks above oceanic subduction zones.

Description: Summary A new global model of the present-day thermochemical state of the lithosphere and upper mantle based on global waveform inversion, satellite gravity and gradiometry measurements, surface elevation and heat flow data has been recently presented: WINTERC-G (Fullea et al., 2021). WINTERC-G is built within an integrated geophysical-petrological framework where the mantle seismic velocity and density fields are computed in a thermodynamically self-consistent framework, allowing for a direct parameterisation in terms of the temperature, pressure and composition of the subsurface rocks. In this paper, we combine WINTERC-G thermal and compositional fields along with laboratory experiments constraining the electrical conductivity of mantle minerals, melt and water, and derive a set of new global three dimensional electrical conductivity models of the upper mantle. The new conductivity models, WINTERC-e, consist of two end-members corresponding to minimum and maximum conductivity of the in-situ rock aggregate accounting for mantle melting, mineral water content and the individual conductivities of the main stable mantle mineral phases. The end-member models are validated over oceans by simulating the magnetic field induced by the ocean M2 tidal currents and comparing the predicted fields with the M2 tidal magnetic field estimated from six-year Swarm satellite observations. Our new conductivity model, derived independently from any surface or satellite magnetic data sets, is however able to predict tidal magnetic fields that are in good agreement with the Swarm M2 tidal magnetic field models estimated by Sabaka et al. (2018, 2020) and Grayver & Olsen (2019). Our predicted M2 tidal magnetic fields differ in amplitudes by about 5-20% from the Swarm M2 tidal magnetic field, with the high conductivity WINTERC-e end-member model accounting for mantle melt and water content capturing the structure of Swarm data better than the low conductivity end-member model. Spherically symmetric conductivity models derived by averaging new WINTERC-e conductivities over oceanic areas are slightly more conductive than the recent global conductivity models AA17 by Grayver et al. (2017) derived from Swarm and CHAMP satellite data in the 60-140 km depth range, while they are less conductive deeper in the mantle. The conductivities in WINTERC-e are about 3-4 times smaller than the AA17 conductivities at a depth of 400 km. Despite the differences in electrical conductivity, our spherically symmetric high conductivity end-member model WINTERC-e captures the structure of Swarm M2 tidal magnetic field almost the same as a state of the art 1D conductivity models derived entirely from magnetic data (AA17, (Grayver et al., 2017). Moreover, we show that realistic lateral electrical conductivity inhomogeneities of the oceanic upper mantle derived from the temperature, melt and water distributions in WINTERC-e contribute to the M2 tidal magnetic field up to ±0.3 nT at 430 km altitude.

Description: Drilling related to development of the platinum-group element deposit of the J-M Reef of the Stillwater Complex returned samples of a rare chromitite seam between anorthosite and norite in a discordant anorthositic body. Plagioclase core An concentrations are marginally higher and modestly reversely zoned on the norite side (average Ancore = 83.8; average Ancore-Anrim = -1.1) as compared with the anorthosite side (Average Ancore 82.5; Average Ancore-Anrim = +1.0). The anorthosites are also characterized by a slightly smaller average plagioclase grain size than plagioclase in the norite (1.41 mm and 1.54 mm, respectively). The chromite can contain single and polyphase inclusions of orthopyroxene, plagioclase, amphibole, biotite and Cl-rich apatite. These and other compositional and textural features, as well as inference from other discordant anorthositic bodies in the Banded series, are all consistent with a chromatographic model of chromite precipitation at a reaction front as a norite protolith reacts with a Cl-rich aqueous fluid saturated in plagioclase alone. Chromitite seam formation is modeled using an infiltration metasomatic model, in which a fluid becomes progressively undersaturated in pyroxene as it rises into the hotter part of the crystal pile. As this pyroxene-undersaturated fluid moves through a noritic protolith, it dissolves the Cr-bearing orthopyroxene to produce an anorthosite. Chromite precipitates at the reaction front between the anorthosite and the norite owing to liberation of Mg and Cr from pyroxene. Continuous redissolution and reprecipitation of chromite occurs as the pyroxene dissolution front moves in direction of fluid flow, collecting the Cr lost from the anorthosite. Owing to Cr dissolved mainly as a neutral divalent cation complex, (CrCl(OH)0, in the solution, but incorporated as a trivalent cation in chromite, the required redox reaction can involve concurrent precipitation of sulfide with chromite. This mechanism differs from some recent models in that the anorthosites are themselves replacement bodies and are not original precipitates from a magma nor formed by loss of mafic material by partial melting. The results show the need for experimental mineral solubility data at T and P conditions appropriate to upper crustal mafic/ultramafic intrusions.

Description: The Paleoproterozoic Bushveld Complex, including the world’s largest layered intrusion and host to world-class stratiform chromium, platinum group element, and vanadium deposits, is a remarkable natural laboratory for investigating the timescales of magmatic processes in the Earth’s crust. A framework for the emplacement, crystallization, and cooling of the Bushveld Complex based on integrated U-Pb zircon-baddeleyite-titanite-rutile geochronology is presented for samples of different rock types from the Bushveld Complex, including ultramafic and mafic cumulates, mineralized horizons, granitic rocks from the roof, and a carbonatite from the nearby alkaline Phalaborwa Complex. The results indicate that (1) the Bushveld Complex was built incrementally over a ∼5 million-year interval from 2060 Ma to 2055 Ma with a peak in magma flux at c.2055–2056 Ma, (2) U-Pb zircon crystallization ages do not decrease in an uninterrupted systematic manner from the base to the top of the intrusion indicating that the Bushveld Complex does not represent the crystallized products of a single progressively filled and cooled magma chamber, and (3) U-Pb rutile dates constrain cooling of the intrusion at the level of the Critical Zone through ∼500 °C by 2053 Ma. The c.2060 Ma Phalaborwa Complex (pyroxenite, syenite, carbonatite + Cu-Fe-phosphate-vermiculite deposits) represents one of the earliest manifestations of widespread Bushveld-related magmatism in the northern Kaapvaal craton. The extended range and out-of-sequence U-Pb zircon dates determined for a harzburgite from the Lower Zone (c.2056 Ma), an orthopyroxenite from the Lower Critical Zone (c.2057 Ma), and orthopyroxenites from the Upper Critical Zone (c.2057–2060 Ma) are interpreted to indicate that the lower part of the Bushveld Complex developed through successive intrusions and accretion of sheet-like intrusions (sills), some intruded at different stratigraphic levels. Crystallization of the main volume of the Bushveld Complex, as represented by the thick gabbroic sequences of the Main Zone and Upper Zone, is constrained to a relatively narrow interval of time (∼1 million years) at c.2055–2056 Ma. Granites and granophyres in the roof, and a diorite in the uppermost Upper Zone, constitute the youngest igneous activity in the Bushveld Complex at c.2055 Ma. Collectively, these results contribute to an emerging paradigm shift for the assembly of some ultramafic-mafic magmatic systems from the conventional “big tank” model to an “amalgamated sill” model. The volume-duration relationship determined for magmatism in the Bushveld Complex, when compared to timescales established for the assembly of other layered intrusions and more silica-rich plutonic-volcanic systems worldwide, is distinct and equivalent to those determined for Phanerozoic continental and oceanic flood basalts that constitute large igneous provinces. Emplacement of the 2055–2060 Ma Bushveld Complex corresponds to the end of the Lomagundi-Jatuli Event, the largest magnitude positive carbon isotope excursion in Earth history, and this temporal correlation suggests that there may have been a contribution from voluminous Bushveld ultramafic-mafic-silicic magmatism to disruptions in the global paleoenvironment.

Description: Summary We examine the potential of frequency-dependent Rayleigh wave ellipticity, derived from microtremors, for the investigation of heterogeneous subsurface structure. Based on numerical simulation, we analyze the effects of interference waves in microtremors, primarily the various propagation directions of the Rayleigh waves, linear polarization waves, and white noise, on the ellipticity frequency-dependent estimation of the Rayleigh waves. A data processing scheme to separate the Rayleigh waves from the interference waves is proposed and verified by synthetic data. We performed a field experiment in the mountainous areas of Southwest China to show that the ellipticity frequency-dependency of Rayleigh waves in the period range of 0.05 to 5 s can be estimated from the microtremor records with the proposed data processing scheme. In addition, the method is feasible for investigating lateral heterogeneity within the top several hundred meters in the mountain regions. The study also reveals that the features of the ellipticity anomaly of a local heterogeneity are related to the propagation directions of the Rayleigh waves, and to reduce the ambiguity of the anomaly, the propagation direction of the waves picked for the ellipticity estimation should be consistent with (along or opposite to) that of the survey line. Then, to eliminate the effects of the phase differences due to the propagation direction, or time, the ellipticity for each location should be estimated by a single event rather than multiple events from the derived Rayleigh wave arrivals.

Description: Summary The differential effective medium (DEM) theory studied in this article describes elastic moduli of a fractured medium with help of differential equations, where crack density is the independent variable and fluid saturation is a parameter. The effective medium is isotropic for randomly oriented flat ellipsoidal cracks and thus fully characterized by two elastic constants. In this article we derive an analytical solution of the equation for Poisson’s ratio and we transform the differential equation for Young’s modulus into a non-linear algebraic equation. Fluid saturation and crack density can then be determined from measured wave propagation velocities by a simple algorithm. We also derive approximate solutions for elastic moduli as a function of crack density and saturation, which allows to quantify the uncertainty of the result due to measurement errors. The DEM theory leads to higher crack densities than the self-consistent (SC) method and to lower crack densities than the non-interacting (NI) theory for measured elastic moduli, while all three methods give similar fluid saturation fractions. As an example of application of our theoretical results, we study weathered granite in the Strengbach water catchment in the Vosges mountains in France. We have performed full waveform sonic logging measurements in an 86 m deep borehole located at an altitude of 1130 m above sea level, which is used for hydro-geophysical and geochemical studies of a granitic aquifer. The logging data allows us to investigate P and S waves in the depth range between 40 and 80 m. The P and S wave propagation velocities take average values of 5.0 km/s and 2.7 km/s, respectively, with the highest values of 5.8 km/s and 3.2 km/s at 75–80 m depth. From these velocities we obtain a water saturation of 75 ± 25 per cent. The crack density describes the degree of weathering of the granite, which generally decreases with depth, but takes high values near layers of strongly weathered granite. Crack density is on average 0.5, with the highest value of 1.0 at 65 m and the lowest value of 0.2 at 75 m depth. The analysis of the full waveform logging data by the DEM method supports results from previous geochemical and hydrological studies in the Strengbach catchment which concluded that water is stored in deeper layers of the granitic aquifer.

Description: Summary The ∼M6 1799 Bouin earthquake is considered as one of the largest earthquakes to have struck Western France. However, the seismogenic source potentially responsible for this event remain marginally documented. We present results from a focused offshore-onshore multidisciplinary survey in its meizoseismal area in order to identify the fault segments that potentially ruptured during this earthquake. Based on macroseismic data and the geology, we focused our study on the so-called Machecoul Fault as a potential source of the 1799 Bouin event. Our survey includes extensive high-resolution seismic reflection, high resolution bathymetry and a one-year seismological survey. These data were combined with existing topography, onshore gravity data and drill data to document the geometry of the Marais Breton / Baie de Bourgneuf basin, the past tectonic activity and the current local microearthquakes at depth along its bounding faults. Offshore and onshore observations suggest a recent activity of the segmented Machecoul Fault bounding the basin to the North. Offshore, the planar contact between the Plio-Quaternary sediments and the basement along the fault trace as well as the thickening of these sedimentary units near this contact suggests tectonic control rather than erosion. Onshore, the recent incision of the footwall of the fault suggests a recent tectonic activity. The temporary local seismological experiment deployed between 2016 and 2017 recorded a diffuse micro-seismicity down to the depth of 22 +/-5 km along the southward dipping Machecoul Fault, associated with predominantly normal fault mechanisms. Altogether, these results suggest that the Machecoul Fault is a serious candidate for being the source of the historical Bouin 1799 earthquake.

Description: SUMMARY The timing of inner core nucleation is a hugely significant event in Earth's evolution and has been the subject of intense debate. Some of the most recent theoretical estimates for the age of nucleation fall throughout the Neoproterozoic era; much younger than previously thought. A young inner core requires faster recent core cooling rates and a likely hotter early core; knowledge of its age would be invaluable in understanding Earth's thermal history and total energy budget. Predictions generated by numerical dynamo models need to be tested against such data, but records are currently much too sparse to constrain the event to a precise period of time. Here, we present results from 720 Ma dolerite dykes (and one sill) from the Franklin Large Igneous Province, which fall within a crucial 300 Myr gap in palaeointensity records. This study uses three independent techniques on whole rocks from 11 sites spread across High Arctic Canada and Greenland to produce virtual dipole moments ranging from 5 to 20 ZAm2 (mean 11 ZAm2); almost one order of magnitude lower than the present-day field. These weak-field results agree with recent ultralow palaeointensity data obtained from Ediacaran rocks formed ∼150 Myr later and may support that the dynamo was on the brink of collapse in the Neoproterozoic prior to a young inner core formation date.

Description: Summary The classical Backus-Gilbert method seeks localized Earth-structure averages at the shortest length scales possible, given a dataset, data errors, and a threshold for acceptable model errors. The resolving length at a point is the width of the local averaging kernel, and the optimal averaging kernel is the narrowest one such that the model error is below a specified level. This approach is well suited for seismic tomography, which maps three-dimensional Earth structure using large sets of seismic measurements. The continual measurement-error decreases and data-redundancy increases have reduced the impact of random errors on tomographic models. Systematic errors, however, are resistant to data redundancy and their effect on the model is difficult to predict. Here, we develop a method for finding the optimal resolving length at every point, implementing it for surface-wave tomography. As in the Backus-Gilbert method, every solution at a point results from an entire-system inversion, and the model error is reduced by increasing the model-parameter averaging. The key advantage of our method stems from its direct, empirical evaluation of the posterior model error at a point. We first measure inter-station phase velocities at simultaneously recording station pairs and compute phase-velocity maps at densely, logarithmically spaced periods. Numerous versions of the maps with varying smoothness are then computed, ranging from very rough to very smooth. Phase-velocity curves extracted from the maps at every point can be inverted for shear-velocity (VS) profiles. As we show, errors in these phase-velocity curves increase nearly monotonically with the map roughness. We evaluate the error by isolating the roughness of the phase-velocity curve that cannot be explained by any Earth structure and determine the optimal resolving length at a point such that the error of the local phase-velocity curve is below a threshold. A 3D VS model is then computed by the inversion of the composite phase-velocity maps with an optimal resolution at every point. The estimated optimal resolution shows smooth lateral variations, confirming the robustness of the procedure. Importantly, the optimal resolving length does not scale with the density of the data coverage: some of the best-sampled locations display relatively low lateral resolution, probably due to systematic errors in the data. We apply the method to image the lithosphere and underlying mantle beneath Ireland and Britain. Our very large dataset was created using new data from Ireland Array, the Irish National Seismic Network, the UK Seismograph Network, and other deployments. A total of 11238 inter-station dispersion curves, spanning a very broad total period range (4–500 s), yield unprecedented data coverage of the area and provide fine regional resolution from the crust to the deep asthenosphere. The lateral resolution of the 3D model is computed explicitly and varies from 39 km in central Ireland to over 800 km at the edges of the area, where the data coverage declines. Our tomography reveals pronounced, previously unknown variations in the lithospheric thickness beneath Ireland and Britain, with implications for their Caledonian assembly and for the mechanisms of the British Tertiary Igneous Province magmatism.

Description: Summary Lamellar magnetism is a source of remanent magnetization in natural rocks different from common bulk magnetic moments in ferrimagnetic minerals. It has been found to be a source for a wide class of magnetic anomalies with extremely high Koenigsberger ratio. Its physical origin are uncompensated interface moments in contact layers of nanoscale ilmenite lamellae inside an hematite host, which also generate unusual low-temperature (low-T) magnetic properties, such as shifted low-T hysteresis loops due to exchange bias. The atomic-magnetic basis for the exchange bias discovered in the hematite-ilmenite system is explored in a series of articles. In this third article of the series, simple models are developed for lamellae interactions of different structures when samples are either cooled in zero-field, or field-cooled in 5 T to temperatures below the ordering temperature of ilmenite. These models are built on the low-temperature measurements described earlier in Paper II. The important observations include: a) the effects of lamellar shapes on magnetic coupling, b) the high-T acquisition of lamellar magnetism and low-T acquisition of magnetization of ilmenite lamellae, c) the intensity of lamellar magnetism and the consequent ilmenite magnetism in populations of randomly oriented crystals, d) lattice-preferred orientation of the titanohematite host crystal populations, and e) the effects of magnetic domain walls in the host on hysteresis properties. Based on exemplary growth models of lamellae with different geometries and surface couplings we here provide simple models to assess and explain the different observations listed above. Already the simplified models show that the shapes of the edges of ilmenite lamellae against their hematite hosts can control the degree of low-T coupling between ilmenite, and the lamellar magnetic moments. The models also explain certain features of the low-T exchange bias in the natural samples and emphasize the role of lattice-preferred orientation upon the intensity of remanent magnetization. The inverse link between ilmenite remanence and exchange-bias shift in bimodal low-T ilmenite lamellae is related to different densities of hematite domain walls induced by the clusters of ilmenite lamellae.

Description: Summary Some geological configurations, like sedimentary basins, are prone to site effects. Basins are often composed of different geological layers whose properties are generally considered as spatially homogeneous or smoothly varying. In this study, we address the influence of small-scale velocity fluctuations on seismic response. For this purpose, we use the Spectral Element method to model the 2D SH wave propagation on a basin of 1.1 km long and ≈ 60 m deep, representing a 2D profile in the city of Nice, France. The velocity fluctuations are modeled statistically as a random process characterized by a Von Karman autocorrelation function and are superimposed to the deterministic model. We assess the influence of the amplitude and correlation length of the random velocities on the surface ground motion. We vary the autocorrelation function’s parameters and compute seismic wavefields in 10 random realizations of the stochastic models. The analyses of our results focus on the Envelope and Phase differences between the waveforms computed in the random and deterministic models; on the variability of ground motion intensity measures, such as the peak ground velocity (PGV), the pseudo-spectral acceleration response (PSA); and the 2D basin response (transfer function). We find that the amplitude of fluctuations has a greater effect on the ground motion variability than the correlation length. Depending on the random medium realization, the ground motion in one stochastic model can be locally amplified or de-amplified with respect to the reference model due to the presence of high or low velocity contrasts, respectively. When computing the mean amplification of different random realizations the results may be smaller than those of the reference media due to the smoothing effect of the average. This study highlights the importance of knowing the site properties at different scales, particularly at small scales, for proper seismic hazard assessment.

Description: Summary Joint inversion of multiphysics data is a practical approach to the integration of geophysical data, which produces models of reduced uncertainty and improved resolution. The development of effective methods of joint inversion requires considering different resolutions of different geophysical methods. This paper presents a new framework of joint inversion of multiphysics data, which is based on a novel formulation of Gramian constraints and mitigates the difference in resolution capabilities of different geophysical methods. Our approach enforces structural similarity between different model parameters through minimizing a structural Gramian term, and it also balances the different resolutions of geophysical methods using a multiscale resampling strategy. The effectiveness of the proposed method is demonstrated by synthetic model study of joint inversion of the P-wave traveltime and gravity data. We apply a novel method based on Gramian constraints and multiscale resampling to jointly invert the gravity and seismic data collected in Yellowstone national Park to image the crustal magmatic system of the Yellowstone. Our results helped to produce a consistent image of the crustal magmatic system of the Yellowstone expressed both in low-density and low-velocity anomaly just beneath the Yellowstone caldera.

Description: Summary Detection of seismic events at or below the noise level is enabled by the use of dense arrays of receivers and corresponding advances in data analysis methods. It is not only important to detect tectonic events, but also events from man-made, non-earthquake sources and events that originate from coupling between the solid Earth and the atmosphere. In urban environments with high ambient noise levels the effectiveness of event detection methods is unclear, particularly when deployment restrictions result in an irregular receiver array geometry. Here we deploy a dense nodal array for 1 month in the highly populated city state of Singapore. We develop a new detection method based on image processing that we call spectrogram stacking, which detects anomalous, coherent spectral energy across the array. It simultaneously detects multiple classes of signal with differing spectral content and aids event classification, so it is particularly useful for signal exploration when signal characteristics are unknown. Our approach detects more local events compared to the traditional STA/LTA and waveform similarity methods, while all methods detect similar numbers of teleseismic and regional earthquakes. Local events are principally man-made non-earthquake sources, with several events from the same location exhibiting repeating waveforms. The closest earthquake occurs in peninsular Malaysia, in an area where no earthquakes have previously been detected. We also detect ground motion over a wide frequency range from discrete thunder events which show complex coupling between acoustic and elastic wavefield propagation. We suggest that care should be taken deciphering local high-frequency tectonic events in areas prone to thunder storms.

Description: Summary In the context of seismic imaging, full waveform inversion (FWI) is increasingly popular. Because of its lower numerical cost, the acoustic approximation is often used, especially at the exploration geophysics scale, both for tests and for real data. Moreover, some research domains such as helioseismology face true acoustic media for which FWI can be useful. In this work, an argument that combines particle relabelling and homogenization is used to show that the general acoustic inverse problem based on band-limited data is intrinsically non-unique. It follows that the results of such inversions should be interpreted with caution. To illustrate these ideas, we consider 2-D numerical FWI examples based on a Gauss-Newton iterative inversion scheme, and demonstrate effects of this non-uniqueness in the local optimization context.

Description: Summary The GRACE and GRACE-FO missions have provided an unprecedented quantification of large-scale changes in the water cycle. However, it is still an open problem of how these missions’ data can be referenced to a ground truth. Meanwhile, stationary optical clocks show fractional instabilities below 10−18 when averaged over an hour, and continue to be improved in terms of stability and accuracy, uptime, and transportability. The frequency of a clock is affected by the gravitational redshift, and thus depends on the local geopotential; a relative frequency change of 10−18 corresponds to a geoid height change of about 1 cm. Here we suggest that this effect could be exploited for sensing large-scale temporal geopotential changes via a network of clocks distributed at the Earth’s surface. In fact, several projects have already proposed to create an ensemble of optical clocks connected across Europe via optical fibre links. Our hypothesis is that a clock network with collocated GNSS receivers spread over Europe – for which the physical infrastructure is already partly in place – would enable us to determine temporal variations of the Earth’s gravity field at time scales of days and beyond, and thus provide a new means for validating satellite missions such as GRACE-FO or a future gravity mission. Here, we show through simulations how glacial, hydrological and atmospheric variations over Europe could be observed with clock comparisons in a future network that follows current design concepts in the metrology community. We assume different scenarios for clock and GNSS uncertainties and find that even under conservative assumptions – a clock error of 10−18 and vertical height control error of 1.4 mm for daily measurements – hydrological signals at the annual time scale and atmospheric signals down to the weekly time scale could be observed.

Description: Summary Reflection seismic imaging usually suffers from a loss of resolution and contrast because of the fluctuations of the wave velocities in the Earth’s crust. In the literature, phase distortion issues are generally circumvented by means of a background wave velocity model. However, it requires a prior tomography of the wave velocity distribution in the medium, which is often not possible, especially in depth. In this paper, a matrix approach of seismic imaging is developed to retrieve a three-dimensional image of the subsoil, despite a rough knowledge of the background wave velocity. To do so, passive noise cross-correlations between geophones of a seismic array are investigated under a matrix formalism. They form a reflection matrix that contains all the information available on the medium. A set of matrix operations can then be applied in order to extract the relevant information as a function of the problem considered. On the one hand, the background seismic wave velocity can be estimated and its fluctuations quantified by projecting the reflection matrix in a focused basis. It consists in investigating the response between virtual sources and detectors synthesized at any point in the medium. The minimization of their cross-talk can then be used as a guide star for approaching the actual wave velocity distribution. On the other hand, the detrimental effect of wave velocity fluctuations on imaging is overcome by introducing a novel mathematical object: The distortion matrix. This operator essentially connects any virtual source inside the medium with the distortion that a wavefront, emitted from that point, experiences due to heterogeneities. A time reversal analysis of the distortion matrix enables the estimation of the transmission matrix that links each real geophone at the surface and each virtual geophone in depth. Phase distortions can then be compensated for any point of the underground. Applied to passive seismic data recorded along the Clark branch of the San Jacinto fault zone, the present method is shown to provide an image of the fault until a depth of 4 km over the frequency range 10-20 Hz with an horizontal resolution of 80 m. Strikingly, this resolution is almost one eighth below the diffraction limit imposed by the geophone array aperture. The heterogeneities of the subsoil play the role of a scattering lens and of a transverse wave guide which increase drastically the array aperture. The contrast is also optimized since most of the incoherent noise is eliminated by the iterative time reversal process. Beyond the specific case of the San Jacinto Fault Zone, the reported approach can be applied to any scales and areas for which a reflection matrix is available at a spatial sampling satisfying the Nyquist criterion.

Description: Summary Thermoremanent magnetization (TRM), the primary magnetic memory of igneous rocks, depends for its stability through geologic time on mineral carriers with high coercivities and high unblocking temperatures. The paleomagnetic record of past magnetic field directions and intensities is the key to unraveling Earth's tectonic history. Yet we still do not fully understand how the familiar mineral magnetite, in the micrometer grain size range typically responsible for stable TRM, acquires and holds its signal. Direct indicators of magnetite remanence-carrying capacity and coercivity at high temperature T are saturation remanence relative to saturation magnetization Mrs/Ms and coercive force Hc. This study is the first to measure the variation of these hysteresis properties for magnetite, from room temperature to the Curie point, across the entire size range from 25 nm to 135 µm, covering superparamagnetic, single-domain, vortex, pseudo-single-domain and multidomain magnetic behaviour. The paper focuses on: (1) Hc(T) and Mrs(T) observations and their reproducibility; (2) mathematical relationships of Hc(T) and Mrs(T) to Ms(T), used in modeling TRM and for unbiased comparisons of thermal variations; (3) the shapes of magnetite grains and the number of domains they contain, revealed by demagnetizing factors N = Hc/Mrs; and (4) the grain-size dependences of Hc and Mrs at ordinary and elevated T, delineating domain structure changes and mechanisms of coercivity.

Description: Background Disparities in colon cancer outcomes have been reported across race and socioeconomic status which may reflect, in part, access to care. We sought to assess the influences of race and median household income (MHI) on outcomes among colon cancer patients with similar access to care. Methods We conducted a prospective, observational study of 1206 stage III colon cancer patients enrolled in the CALGB 89803 randomized adjuvant chemotherapy trial. Race was self-reported by 1116 White and 90 Black patients at study enrollment; MHI was determined by matching 973 patients’ home zip codes with publicly-available United States Census 2000 data. Multivariate analyses were adjusted for baseline sociodemographic, clinical, dietary, and lifestyle factors. All statistical tests were 2-sided. Results Over a median follow-up of 7.7 years, the adjusted hazard ratios (HRs) for Blacks (compared to Whites) were 0.94 (95% confidence interval [CI] = 0.66–1.35; P = .75) for disease-free survival, 0.91 (95%CI = 0.62–1.35; P = .65) for recurrence-free survival, and 1.07 (95%CI = 0.73–1.57; P = .73) for overall survival. Relative to patients in the highest MHI quartile, the adjusted HRs for patients in the lowest quartile were 0.90 (95%CI, 0.67–1.19; Ptrend=0.18) for disease-free survival, 0.89 (95%CI = 0.66–1.22; Ptrend=0.14) for recurrence-free survival, and 0.87 (95%CI = 0.63–1.19; Ptrend=0.23) for overall survival. Conclusion In this study of patients with similar healthcare access, no statistically significant differences in outcomes were found by race or MHI. The substantial gaps in outcomes previously observed by race and MHI may not be rooted in differences in tumor biology, but in access to quality care.

Description: Background Branched-chain amino acids (BCAAs) are essential amino acids common throughout the US diet. While circulating BCAAs have been implicated in insulin resistance and some obesity-related cancers, the relationship between dietary intake of BCAAs and incident breast cancer is unknown. We sought to evaluate the association between long-term dietary intakes of BCAAs and invasive breast cancer risk. Methods Our analyses included 196,161 women from the Nurses’ Health Study and Nurses’ Health Study II longitudinal cohorts. Average intakes of total and individual BCAAs (isoleucine, leucine, valine) were estimated from repeated diet questionnaires and incident self-reported breast cancer cases were confirmed via medical record review. Cox proportional hazards models, adjusted for reproductive history, lifestyle, body mass index (BMI) and other breast cancer risk factors, were used to estimate hazard ratios and 95% confidence intervals. Results We observed 10,046 incident cases of breast cancer over a median of 20.8 years of follow-up. No associations between dietary intakes of total or individual BCAAs with breast cancer risk were observed. Compared with women in the bottom quintile of BCAA intake, the hazard ratio of breast cancer for those in the top quintile was 1.05 (95% confidence interval = 0.98 to 1.12; 2-sided Ptrend=0.20). Findings were consistent across molecular subtypes and according to type 2 diabetes diagnosis and BMI categories. Conclusions Dietary intakes of BCAAs are not likely a risk factor for breast cancer.