ALBERT

Beschreibung: Background Benign meningiomas are the most frequently reported central nervous system tumors in the United States (US), with increasing incidence in past decades. However, the future trajectory of this neoplasm remains unclear. Methods We analyzed benign meningioma incidence of cases identified by any means (eg, radiographically with or without microscopic confirmation) in US Surveillance Epidemiology and End Results (SEER) cancer registries among 35–84-year-olds during 2004–2017 by sex and race/ethnicity using age-period-cohort (APC) models. We employed APC forecasting models to glean insights regarding the etiology, distribution, and anticipated future (2018–2027) public health impact of this neoplasm. Results In all groups, meningioma incidence overall increased through 2010, then stabilized. Temporal declines were statistically significant overall and in most groups. JoinPoint analysis of cohort rate-ratios identified substantial acceleration in White men born after 1963 (from 1.1% to 3.2% per birth year); cohort rate-ratios were stable or increasing in all groups and all birth cohorts. We forecast that meningioma incidence through 2027 will remain stable or decrease among 55–84-year-olds but remain similar to current levels among 35–54-year-olds. Total meningioma burden in 2027 is expected to be approximately 30,470 cases, similar to the expected case count of 27,830 in 2018. Conclusions Between 2004–2017, overall incidence of benign meningioma increased and then stabilized or declined. For 2018–2027, our forecast is incidence will remain generally stable in younger age groups but decrease in older age groups. Nonetheless, the total future burden will remain similar to current levels because the population is aging.

Beschreibung: Anisotropy affects the focal mechanism and makes it complicated. A shear motion generates a pure double-couple (DC) source in isotropic media. While in anisotropic media, it will produce non-DC components, which contain isotropic (ISO) and compensated linear vector dipole (CLVD) components. Besides, coupled with the diversity of fault motion, the source may become extremely complicated. In this paper, the seismic moment tensor is obtained based on the dislocation model, and then a variety of analyses are performed with the moment tensor, including moment tensor decomposition, radiation pattern, radiated energy ratio and seismic propagation characteristics. Since the anisotropy of the medium also influences seismic wave propagation, a hypothesis is made that the source region is minimal and anisotropic, but the propagation path is isotropic. The research gives some interesting conclusions. It is found that the anisotropy mainly affects the focal mechanism under low slope angle while high slope angle has little effect on the polarity. In terms of the moment tensor decomposition, if only one of ISO or CLVD exists, it can be asserted that the source region is anisotropic because ISO components are accompanied by CLVD components in isotropy media. As for the DC component, the results indicate it is one of the most important factors for determining the ratio of radiant energy. This paper presents some valuable findings of the focal mechanism of the general dislocation source under anisotropy, which helps to recognise the source characteristics of the earthquake and build solid foundations for the subsequent inversion of the focal mechanism.

Beschreibung: Background Having a child diagnosed with cancer is a devastating experience that may affect parentś mental health. We aimed to assess the risk of hospital contacts for psychiatric disorders in parents of children with cancer. Methods We conducted a nationwide population-based cohort study using Danish registry data. Parents of children diagnosed with cancer between 1982-2014 (n = 6,689 mothers, n = 5,509 fathers) were matched with comparison parents of cancer-free children (n = 67,544 mothers, n = 55,756 fathers). We used Cox proportional hazards models to estimate the risk of hospital contacts for any psychiatric disorder and specific disorders. Cox models were also used to investigate socio-demographic and cancer-related risk factors for psychiatric disorders. Results Incidence rates of hospital contacts for any psychiatric disorder were 426 per 100,000 person-years in mothers of children with cancer and 345 per 100,000 person-years in comparison mothers. For fathers the respective incidence rates were 260 and 262 cases per 100,000 person-years. Compared to parents of cancer-free children, mothers of children with cancer were at an increased risk of hospital contacts for any psychiatric disorder (HR = 1.23, 95%-CI = 1.12-1.36), while no elevated risk was seen in fathers (HR = 0.99, 95%-CI = 0.87-1.13). Among mothers, risks were particularly elevated for affective and stress-related disorders. Parents of deceased children and children diagnosed at a younger age were at particular risk of hospital contacts for psychiatric disorders. Conclusion Hospital contacts for psychiatric disorders were overall rare. Healthcare professionals should draw attention to subgroups of vulnerable parents to meet their needs of support and adequate treatment.

Beschreibung: Summary As the largest and most active intracontinental orogenic belt on Earth, the Tien Shan (TS) is a natural laboratory for understanding the Cenozoic orogenic processes driven by the India-Asia collision. On 19 January 2020, a Mw 6.1 event stuck the Kalpin region, where the southern frontal TS interacts with the Tarim basin. To probe the local ongoing orogenic processes and potential seismic hazard in the Kalpin region, both interseismic and instantaneous deformation derived from geodetic observations are employed in this study. With the constraint of interseismic global navigation satellite system (GNSS) velocities, we estimate the décollement plane parameters of the western Kalpin nappe based on a two-dimensional dislocation model, and the results suggest that the décollement plane is nearly subhorizontal with a dip of ∼3° at a depth of 24 km. Then, we collect both Sentinel-1 and ALOS-2 satellite images to capture the coseismic displacements caused by the 2020 Kalpin event, and the interferometric synthetic aperture radar (InSAR) images show a maximum displacement of 7 cm in the line of sight near the epicentral region. With these coseismic displacement measurements, we invert the source parameters of this event using a finite-fault model. We determine the optimal source mechanism in which the fault geometry is dominated by thrust faulting with an E–W strike of 275° and a northward dip of 11.2°, and the main rupture slip is concentrated within an area 28.0 km in length and${ m{,,}}$10.3 km in width, with a maximum slip of 0.3 m at a depth of 6–8 km. The total released moment of our preferred distributed slip model yields a geodetic moment of 1.59 × 1018 N$cdot $m, equivalent to Mw 6.1. The contrast of the décollement plane depth from interseismic GNSS and the rupture depth from coseismic InSAR suggests that a compression still exists in the Kalpin nappe forefront, which is prone to frequent moderate events and may be at risk of a much more dangerous earthquake.

Beschreibung: Summary The Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) laser altimetry mission, launched in September 2018, uses 6 parallel lidar tracks with very fine along-track resolution (15 m) to measure the topography of ice, land, and ocean surfaces. Here we assess the ability of ICESat-2 ocean data to recover oceanographic signals ranging from surface gravity waves to the marine geoid. We focus on a region in the tropical Pacific and study photon height data in both the wavenumber and space domain. Results show that an ICESat-2 single track can recover the marine geoid at wavelengths 〉 20 km which is similar to the best radar altimeter data. The wavelength and propagation direction of surface gravity waves are sometimes well resolved by using a combination of the strong and weak beams, which are separated by 90 m. We find higher than expected power in the 3 km to 20 km wavelength band where geoid and ocean signals should be small. This artificial power is caused by the projection of 2-D surface waves with ∼300 m wavelengths into longer wavelengths (5-10 km) because of the 1-D sampling along the narrow ICESat-2 profile. Thus ICESat-2 will not provide major improvements to the geoid recovery in most of the ocean.

Beschreibung: Background Cancer Centers have a responsibility to help patients manage the costs of their cancer treatment. This article describes the availability of financial navigation services within the National Cancer Institute (NCI)-Designated Cancer Centers. Methods Data were obtained from the NCI Survey of Financial Navigation Services and Research, an online survey administered to NCI-Designated Cancer Centers from July to September 2019. Of the 62 eligible Centers, 57 completed all or most of the survey, for a response rate of 90.5%. Results Nearly all Cancer Centers reported providing help with applications for pharmaceutical assistance programs and medical discounts (96.5%), health insurance coverage (91.2%), assistance with non-medical costs (96.5%), and help understanding medical bills and out-of-pocket costs (85.9%). Although other services were common, in some cases they were only available to certain patients. These services included direct financial assistance with medical and non-medical costs and referrals to outside organizations for financial assistance. The least common services included medical debt management (63.2%), detailed discussions about the cost of treatment (54.4%), and guidance about legal protections (50.1%). Providing treatment cost transparency to patients was reported as a common challenge: 71.9% of Centers agreed or strongly agreed that it is difficult to determine how much a cancer patient’s treatment will cost and 70.2% of oncologists are reluctant to discuss financial issues with patients. Conclusions Cancer Centers provide many financial services and resources. However, there remains a need to build additional capacity to deliver comprehensive financial navigation services and to understand the extent to which patients are referred and helped by these services.

Beschreibung: Background Obesity and inactivity are associated with increased risk of cancer related- and overall mortality in breast cancer, but there are few data in metastatic disease. Methods CALGB 40502 was a randomized trial of first-line taxane-based chemotherapy for patients with metastatic breast cancer. Height and weight were collected at enrollment. After 299 patients enrolled, the study was amended to assess recreational physical activity (PA) at enrollment using the Nurses’ Health Study Exercise Questionnaire. Associations with progression-free survival (PFS) and overall survival (OS) were evaluated using stratified Cox modeling (strata included hormone receptor status, prior taxane, bevacizumab use, and treatment arm). Results 799 patients were enrolled and at the time of data lock, median follow-up was 60 months. At enrollment, median age was 56.7 years, 73.1% of participants had hormone receptor-positive cancers, 42.6% had obesity, and 47.6% engaged in less than 3 metabolic equivalents of task (MET)-hours of PA/week (

Beschreibung: Full-waveform inversion (FWI) is among the most effective methods of velocity modelling in seismic exploration. However, because of the strong nonlinearity of the FWI, if the velocity in the target geobody is not sharply different from that in its surroundings, the total variation (TV) of the model will not be sufficiently sparse. To alleviate this issue, we propose a novel TV-regularised FWI method that can consider the sparsity of the high-order regularisation operator and consequently improve the stability of the inversion process and produce more focused model boundaries. We use a split-Bregman algorithm to solve the inversion optimisation problem while building the TV-regularised objective function. We show that stable model updates can be obtained by this algorithm, which proved to be effective and reliable in the numerical tests. These tests also show that the proposed method converges faster, can model the velocity domain better than conventional methods and can effectively identify layer boundaries with a weak velocity contrast. We conclude that the novel FWI method based on high-order TV regularisation is robust and accurate.

Beschreibung: Evolutionary mechanisms driving the diversification of pelagic animals remain poorly understood, partly due to the high levels of gene flow in the open ocean. We use molecular phylogenetics, morphological, and phylogeographic approaches to test the allopatric speciation model in respect to the Atlantic krill genus Nematoscelis. Based on our observations, we hypothesize that diversification in genus Nematoscelis may occur through three progressing stages: (i) populations separated geographically and divergence occurred in the mitochondrial COI gene only (Nematoscelis megalops, one clade of Nematoscelis tenella), (ii) morphology diverged (clades of Nematoscelis microps and Nematoscelis atlantica), and (iii) the nuclear H3 gene diverged (clades of N. tenella). Our results confirm allopatric expectations and the dispersal-limiting speciation model. We propose that the primary driver of diversification is geographic isolation coupled with hydrology-linked gene barriers at ∼14–22°N (new) and ∼30°S. The second driver preventing hybridization of diverged populations is linked to external morphology, i.e. enlarged photophores and chitin saddles on the pleon of males, which facilitate sexual selection by female choice. Same-male forms, even belonging to different species, rarely co-occur, which makes the selection effective and not biased. Our results implicate a significant role of non-copulatory characters in Nematoscelis speciation.

Beschreibung: Background Cancer patients with COVID-19 disease have been reported to have double the case fatality rate of the general population. Methods A systematic search of PubMed, Embase, and Cochrane Central was done for studies on cancer patients with COVID-19. Pooled proportions were calculated for categorical variables. Odds ratio (OR) and forest plots (Random-effects model) were constructed for both primary and secondary outcomes.  Results This systematic review of 38 studies and meta-analysis of 181,323 patients from 26 studies included 23,736 cancer patients. Our meta-analysis shows that cancer patients with COVID-19 have a higher likelihood of death (n = 165,980, OR = 2.54, 95% confidence interval [CI] = 1.47 to 4.42), which was largely driven by mortality among patients in China. Cancer patients were more likely to be intubated. Among cancer subtypes, the mortality was highest in hematological malignancies (n = 878, OR = 2.39, 95% CI = 1.17 to 4.87) followed by lung cancer (n = 646, OR = 1.83, 95% CI = 1.00 to 3.37). There was no association between receipt of a particular type of oncologic therapy and mortality. Our study showed that cancer patients affected by COVID-19 are a decade older than the normal population and have a higher proportion of co-morbidities. There was insufficient data to assess the association of COVID-directed therapy and survival outcomes in cancer patients.  Conclusion Cancer patients with COVID-19 disease are at increased risk of mortality and morbidity. A more nuanced understanding of the interaction between cancer-directed therapies and COVID-19-directed therapies is needed. This will require uniform prospective recording of data, possibly in multi-institutional registry databases.

Beschreibung: Summary We expand the application of spatial autocorrelation (SPAC) from typical 1D Vs profiles to quasi-3D imaging via Bayesian Monte-Carlo inversion (BMCI) using a dense nodal array (49 nodes) located at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE) site. Combinations of 4 and 9 geophones in subarrays provide for 36 and 25 1D Vs profiles, respectively. Profiles with error bars are determined by calculating coherency functions that fit observations in a frequency range of 0.2–5 Hz. Thus, a high-resolution quasi-3D Vs model from the surface to 2.0 km depth is derived and shows that surface-parallel sedimentary strata deepen to the west, consistent with a 3D seismic reflection survey. Moreover, the resulting Vs profile is consistent with a Vs profile derived from distributed acoustic sensing (DAS) data located in a borehole at the FORGE site. The quasi-3D velocity model shows that the base of the basin dips ∼22o to the west and topography on the basement interface coincident with the Mag Lee Wash suggests that the bedrock interface is an unconformity.

Beschreibung: Summary Scattered seismic coda waves are frequently used to characterize small scale medium heterogeneities, intrinsic attenuation or temporal changes of wave velocity. Spatial variability of these properties raises questions about the spatial sensitivity of seismic coda waves. Especially the continuous monitoring of medium perturbations using ambient seismic noise led to a demand for approaches to image perturbations observed with coda waves. An efficient approach to localize spatial and temporal variations of medium properties is to invert the observations from different source-receiver combinations and different lapse times in the coda for the location of the perturbations. For such an inversion, it is key to calculate the coda-wave sensitivity kernels which describe the connection between observations and the perturbation. Most discussions of sensitivity kernels use the acoustic approximation in a spatially uniform medium and often assume wave propagation in the diffusion regime. We model 2-D multiple non-isotropic scattering in a random elastic medium with spatially variable heterogeneity and attenuation using the radiative transfer equations which we solve with the Monte-Carlo method. Recording of the specific energy density of the wavefield that contains the complete information about the energy density at a given position, time and propagation direction allows us to calculate sensitivity kernels according to rigorous theoretical derivations. The practical calculation of the kernels involves the solution of the adjoint radiative transport equations. We investigate sensitivity kernels that describe the relationships between changes of the model in P- and S-wave velocity, P- and S-wave attenuation, and the strength of fluctuation on the one hand and seismogram envelope, travel time changes and waveform decorrelation as observables on the other hand. These sensitivity kernels reflect the effect of the spatial variations of medium properties on the wavefield and constitute the first step in the development of a tomographic inversion approach for the distribution of small-scale heterogeneity based on scattered waves.

Beschreibung: Summary The Pacific Coast of Central North America is a geodynamically complex region which has been subject to various geophysical processes operating on different time scales. Glacial isostatic adjustment (GIA), the ongoing deformational response of the solid Earth to past deglaciation, is an important geodynamic process in this region. In this study we apply Earth models with 3D structure to determine if the inclusion of lateral structure can explain the poor performance of 1D models in this region. Three different approaches are used to construct 3D models of the Earth structure. For the first approach, we adopt an optimal 1D viscosity structure from previous work and add lateral variations based on four global seismic shear wave velocity anomalies and two global lithosphere thickness models. The results based on these models indicate that the addition of lateral structure significantly impacts modelled RSL changes, but the data-model fits are not improved. The global seismic models are limited in spatial resolution and so two other approaches were considered to produce higher resolution models of 3D structure: inserting a regional seismic model into two of the global seismic models and, explicitly incorporating regional structure of the Cascadia subduction zone and vicinity, i.e. the subducting slab, the overlying mantle wedge, and the plate boundary interface. The results associated with these higher resolution models do not reveal any clear improvement in satisfying the RSL observations, suggesting that our estimates of lateral structure are inaccurate and/or the data-model misfits are primarily due to limitations in the adopted ice-loading histories. The different realisations of 3D Earth structure gives useful insight to uncertainty associated with this aspect of the GIA model. Our results indicate that improving constraints on the deglacial history of the southwest sector of the Cordilleran ice sheet is an important step towards developing more accurate of GIA models for this region.

Beschreibung: Diet-based annual biomass indices can potentially use predator stomach contents to provide information about prey biomass and may be particularly useful for species that are otherwise poorly sampled, including ecologically important forage fishes. However, diet-based biomass indices may be sensitive to underlying ecological dynamics between predators and prey, such as predator functional responses and changes in overlap in space and time. To evaluate these factors, we fit spatio-temporal models to stomach contents of five Atlantic herring (Clupea harengus) predators and survey catch data for predators and Atlantic herring. We identified drivers of variation in stomach contents, evaluated spatial patterns in stomach content data, and produced predator-specific indices of seasonal Atlantic herring biomass. After controlling for spatio-temporal processes and predator length, diet-based indices of biomass shared similar decadal trends but varied substantially between predators and seasons on shorter time scales. Diet-based indices reflected prey biomass more than prey availability, but weak correlations indicated that not all biological processes were controlled for. Results provide potential guidance for developing diet-based biomass indices and contribute to a body of evidence demonstrating the utility of predator diet data to provide information about relative prey biomass.

Beschreibung: Summary We develop and apply a method to constrain the space- and frequency-dependent location of ambient noise sources. This is based on ambient noise cross-correlation inversion using numerical wavefield simulations, which honour 3-D crustal and mantle structure, ocean loading, and finite-frequency effects. In the frequency range from 3 - 20 mHz, our results constrain the global source distribution of the Earth’s hum, averaged over the southern hemisphere winter season of 9 years. During southern-hemisphere winter, the dominant sources are largely confined to the southern hemisphere, the most prominent exception being the Izu-Bonin-Mariana arc, which is the most active source region between 12 - 20 mHz. Generally, strong hum sources seem to be associated with either coastlines or bathymetric highs. In contrast, deep ocean basins are devoid of hum sources. While being based on the relatively small number of STS-1 broadband stations that have been recording continuously from 2004 - 2013, our results demonstrate the practical feasibility of a frequency-dependent noise source inversion that accounts for the complexities of 3-D wave propagation. It may thereby improve full-waveform ambient noise inversions and our understanding of the physics of noise generation.

Beschreibung: Oncology health-care workers (HCWs) are facing substantial stressors during the current coronavirus disease 2019 (COVID-19) pandemic, resulting in a wide range of acute stress responses. To appropriately meet the growing mental health needs of HCWs, it is imperative to differentiate expectable stress responses from post-traumatic stress disorder and mental illness, as traditional mental health interventions may pathologize healthy stress reactions and risk retraumatizing HCWs under acute duress. Further, HCWs are experiencing protracted forms of acute stress as the pandemic continues, including moral injury, and require mental health interventions that are flexible and can adapt as the acuity of stressors changes. Previously developed frameworks to support people experiencing acute stress, such as Psychological First Aid, are particularly relevant for HCWs in the ongoing pandemic. Acute stress interventions like Psychological First Aid are guided by the Stress Continuum Model, which conceptualizes stress reactions on a continuum, from a zone of normal readiness and expectable consequences, to a zone of more persistent and extreme reactions such as post-traumatic stress disorder and major depression. Key principles of the Stress Continuum Model include the expectation that emotional reactivity does not lead to psychiatric problems, that interventions need to be appropriately targeted to symptoms along the stress continuum, and that people will return to normal recovery. Various core actions to reduce acute stress include delivering practical assistance, reducing arousal, mobilizing support, and providing targeted collaborative services. This non-pathologizing approach offers a valuable framework for delivering both individual and organizational-level interventions during the COVID-19 pandemic.

Beschreibung: Natural fractures are usually multiscale in size, orientations and distribution, resulting in complex anisotropic characteristics. Analytical methods for quantifying the associated effective elastic properties are based on some assumptions, such as dilute fracture concentration and regular-shaped fractures, which do not occur in actual reservoirs. Here, we conduct anisotropic finite-element modeling of effective elastic properties of complex fractured rocks using the least-square fitting method. The algorithm is developed for a 3D case and validated by classical effective medium theories for models with different fracture densities. The results of the 3D numerical method agree well with the theoretical predictions at low fracture density. The model also considers the interactions among fractures to calculate equivalent stiffness tensors at high fracture density. Three 2D fracture models are simulated to demonstrate the basic behavior of stress interactions and their effect on the overall elasticity under different fracture densities. We applied the developed model to 3D natural fractures built from a real outcrop, and we found that the fracturing pattern significantly affects the effective anisotropy properties. The resultant P-wave phase velocities as functions of the incidence angle and frequency are anisotropic. This study provides a great potential to calculate equivalent stiffness tensors and anisotropic properties of 3D multiscale natural fractures.

Beschreibung: Imaging of vertical structures is a challenge in the seismic imaging field. The conventional imaging methods for vertical structures are highly dependent on the reference model or boreholes. Time-reversed mirror imaging can effectively image the vertical structures based on the multiples and a smoothed velocity model without the need of accurate seismic wavelet estimation. Although the Laplacian operator is applied in time-reversed mirror imaging, there still exists severe residual noise. In this study, we developed a new imaging denoising strategy and an X-shaped supplement denoising operator for time-reversed mirror imaging based on the geometric features of the image and the causes of imaging noise. Synthetic results for the single- and double-staircase model prove the powerful denoising capacity of the X-shaped supplement denoising operator. In addition, the results of a Marmousi model prove that the X-shaped denoising operator can also effectively suppress the noise when applying time-reversed mirror imaging method to image complex inclined structures. However, the X-shaped denoising operator still contains some limitations, such as non-amplitude-preserving.

Beschreibung: Natural rocks are polymineral composites with complex microstructures. Such strong heterogeneities significantly affect the estimation of effective moduli by some theoretical models. First, we have compared the effective moduli of isotropic rocks predicted by the Kuster–Toksöz (KT) model and the Mori–Tanaka (MT) model. The widely used KT model only has finite precision in many cases because of its assumption that is restricted to the first-order scattering approximation. However, the MT model based on the Eshelby tensor in mesomechanics has the advantage of predicting effective moduli of rocks, especially when the volume fraction of embedded inclusions is sufficiently large. In addition, the MT model can be used to predict the effective modulus of anisotropic rocks, but the KT model cannot. For a certain kind of shale or tight sandstones, which are viewed as isotropic composites, both the models work well. For the medium containing spherical pores, both the models produce the same results, whereas for ellipsoidal pores the MT model is more accurate than the KT model, validated by the finite element simulations. In what follows, the applicable ranges of simplified formulas for pores with needle, coin and disk shapes, widely used in engineering, are quantitatively given based on the comparison with the results according to the reduced ellipsoidal formulas of the MT and KT models. These findings provide a comprehensive understanding of the two models in calculating the effective modulus of rocks, which are beneficial to such areas as petroleum exploration and exploitation, civil engineering, and geophysics.

Beschreibung: Unknown coal seam goafs will pose various safety hazards in construction and engineering designs, thus the accurate detections of coal seam goafs have become engineering problems that urgently require effective solutions. Multi-grounded source transient electromagnetic methods have the advantages of large detection depths and the easy deployment of emission sources. Therefore, they can be used for explorations in such complex areas as mountains, lakes and swamps. Previously, grounded source transient electromagnetic methods had only one emission source arranged on the surface, and were relatively rarely used in field explorations with multi-grounded sources. This study analyses the electromagnetic response differences between multi-grounded sources and a single-grounded source. The results reveal that the electromagnetic responses of multi-grounded sources were larger. Transient electromagnetic signals were be targeted using combinations of multi-grounded sources, which successfully strengthened the detection abilities. As a result, this study was able to achieve the goals of increasing the detection depths and improving the ability to distinguish geological anomalies. In addition, this research investigation referred to the theory of implicit functions and used the z components of the decay voltage to calculate the apparent resistivity. Finally, the results of the field data of a coal goaf located in Gansu Province, China, showed that the applied multi-grounded sources transient electromagnetic method could obtain higher resolution in coal seam goaf resistivity distribution information.

Beschreibung: The large computational cost and memory requirement for the finite difference frequency domain (FDFD) method limit its applications in seismic wave simulation, especially for large models. For conventional FDFD methods, the discretisation based on minimum model velocity leads to oversampling in high-velocity regions. To reduce the oversampling of the conventional FDFD method, we propose a trapezoid-grid FDFD scheme to improve the efficiency of wave modeling. To alleviate the difficulty of processing irregular grids, we transform trapezoid grids in the Cartesian coordinate system to square grids in the trapezoid coordinate system. The regular grid sizes in the trapezoid coordinate system correspond to physical grid sizes increasing with depth, which is consistent with the increasing trend of seismic velocity. We derive the trapezoid coordinate system Helmholtz equation and the corresponding absorbing boundary condition, then get the FDFD stencil by combining the central difference method and the average-derivative method (ADM). Dispersion analysis indicates that our method can satisfy the requirement of maximum phase velocity error less than $1\%$ with appropriate parameters. Numerical tests on the Marmousi model show that, compared with the regular-grid ADM 9-point FDFD scheme, our method can achieve about $80\%$ computation efficiency improvement and $80\%$ memory reduction for comparable accuracy.

Beschreibung: SUMMARY In this study, we aim to solve the seismic inversion in the Bayesian framework by generating samples from the posterior distribution. This distribution incorporates the uncertainties in the seismic data, forward model, and prior information about the subsurface model parameters; thus, we obtain more information through sampling than through a point estimate (e.g. maximum a posteriori method). Based on the numerical cost of solving the forward problem and the dimensions of the subsurface model parameters and observed data, sampling with Markov chain Monte Carlo (MCMC) algorithms can be prohibitively expensive. Herein, we consider the promising Langevin dynamics MCMC algorithm. However, this algorithm has two central challenges: (1) the step size requires prior tuning to achieve optimal performance and (2) the Metropolis–Hastings acceptance step is computationally demanding. We approach these challenges by proposing an adaptive step-size rule and considering the suppression of the Metropolis–Hastings acceptance step. We highlight the proposed method’s potential through several numerical examples and rigorously validate it via qualitative and quantitative evaluation of the sample quality based on the kernelized Stein discrepancy (KSD) and other MCMC diagnostics such as trace and autocorrelation function plots. We conclude that, by suppressing the Metropolis–Hastings step, the proposed method provides fast sampling at efficient computational costs for large-scale seismic Bayesian inference; however, this inflates the second statistical moment (variance) due to asymptotic bias. Nevertheless, the proposed method reliably recovers important aspects of the posterior, including means, variances, skewness and 1-D and 2-D marginals. With larger computational budget, exact MCMC methods (i.e. with a Metropolis–Hastings step) should be favoured. The results thus obtained can be considered a feasibility study for promoting the approximate Langevin dynamics MCMC method for Bayesian seismic inversion on limited computational resources.

Beschreibung: SUMMARY Seismic shear wave velocity (S-velocity) shows a decrease towards the base of ice sheets in Antarctica and Greenland that is not accompanied by a corresponding decrease in compressional velocity (P-velocity). This decrease has been interpreted as arising from liquid water below the melting point (pre-melt water) at grain boundaries, but the lack of a corresponding decrease in P-velocity has not been explained. Representing grain boundaries as displacement discontinuities allows the change in P- and S-velocities to be written as functions of the normal and shear compliance of the grain boundaries. This allows the normal-to-shear compliance ratio of the grain boundaries to be constrained, and seismic anisotropy resulting from a partial orientation of grain boundaries to be estimated. This approach demonstrates that the observed reduction in S-velocity with no significant decrease in P-velocity near the base of ice sheets in Antarctica and Greenland can be explained by pre-melt water at small aperture grain boundaries. Such water may enable sliding along the grain boundaries and so may enhance creep of ice near the base of ice sheets. If stress state is anisotropic the aperture of water-containing grain boundaries may vary with azimuth, with the most open grain boundaries oriented with strikes perpendicular to least compressive stress. Microcracks and fractures may be treated also as displacement discontinuities and, together with oriented grain boundaries, may contribute to shear wave splitting as observed in West Antarctica in a fast-moving ice stream.

Beschreibung: Thermally coupled constitutive relations are generally used to determine material constants and elastic moduli (Young's modulus and shear modulus) of solid media. Conventional studies on this issue are mainly based on the linear temperature dependence of elastic moduli, whereas analytical difficulties are often encountered in theoretical studies on nonlinear temperature dependence, particularly at high temperatures. This study investigates the thermally coupled constitutive relations for elastic moduli and material constants using the assumption of axisymmetric fields, with applications to geologic materials (marble, limestone and granite). The Taylor power series of the Helmholtz free energy function within dimensionless temperatures could be used to develop the thermally coupled constitutive relations. The thermoelastic equivalent constitutive equations were formulated under the generalized Hooke's law. The material constants of solid rocks were determined by fitting experimental data using axisymmetric stress and strain fields at different temperatures, based on their thermomechanical properties. For these geologic materials, the resultant equivalent elastic moduli and deformations were in good agreement with those from the experimental measurements. Thermal stresses, internal moisture evaporation and internal rock compositions significantly affected the experimental results. This study provides a profound understanding of the thermally coupled constitutive relations that are associated with the thermomechanical properties of solid rocks exposed to high temperatures.

Beschreibung: To improve the imaging quality of wide-azimuth seismic data and enhance the uniformity of the attributes between adjacent bins, we developed a novel interpolation method in the offset-vector tiles (OVT) domain for wide-azimuth data. The orthogonal matching pursuit (OMP) interpolation method based on the Fourier transform is a frequency-domain processing technique based on discrete Fourier interpolation that achieves the goal of anti-aliasing by extracting the weight factor in the effective band from low-frequency data without aliasing. For data reconstruction, the OMP-based data interpolation technique in the OVT domain comprehensively uses the seismic data in five dimensions: the vertical and horizontal coordinates, time, offset and azimuth. Compared with conventional three-dimensional data interpolation, five-dimensional interpolation in the OVT domain is more accurate and achieves better results in practical applications.

Beschreibung: In the last decade, a significant shift in the marine seismic acquisition business has been made where ocean bottom nodes gained a substantial market share from streamer cable configurations. Ocean bottom node acquisition (OBN) can acquire wide azimuth seismic data over geographical areas with challenging deep and shallow bathymetries and complex subsurface regimes. When the water bottom is rugose and has significant elevation differences, OBN data processing faces a number of challenges, such as denoising of the vertical geophone, accurate wavefield separation, redatuming the sparse receiver nodes from ocean bottom to sea level and multiple attenuation. In this work, we review a number of challenges using real OBN data illustrations. We demonstrate corresponding solutions using processing workflows comprising denoising the vertical geophones by using all four recorded nodal components, cross-ghosting the data or using direct wave to design calibration filters for up- and down-going wavefield separation, performing one-dimensional reversible redatuming for stacking QC and multiple prediction, and designing cascaded model and data-driven multiple elimination applications. The optimum combination of the mentioned technologies produced cleaner and high-resolution migration images mitigating the risk of false interpretations.

Beschreibung: The changes in the acoustic emission signals of sandstone after treatment at different high temperatures are examined in this study. The results show that there is a critical point on the cumulative energy curve of the acoustic emission signals (almost between 60 and 90% of the ratio of the loading time and the total loading time), which can be used to identify the failure of sandstone that has been damaged by exposure to a temperature of 900°C. As the temperature increases, the position of the critical point gradually changes, which indicates that high temperatures increase the plasticity of rock, and this gradually reduces the brittleness. The changes in b-value of acoustic emission shows that the transition behavior of rock from brittleness to plasticity is more obvious at temperatures higher than 600°C, and the large-scale micro cracking takes place at that temperature range, which is the main reason for the weakening and brittleness and the strengthening of plasticity of the sandstone.

Beschreibung: Summary Magnetotelluric (MT) data allow for electrical resistivity probing of the Earth's subsurface. Integration of resistivity models in passive margin studies could help disambiguate non-unique interpretations of crustal composition derived from seismic and potential field data, a recurrent issue in the distal domain. In this contribution, we present the first marine MT data in the Barents Sea, derived from industrial controlled-source electromagnetic (CSEM) surveys. We characterize data quality, dimensionality, depth penetration and elaborate an analysis strategy. The extensive MT database consists of 337 receivers located along 7 regional transects, emanating from ∼70,000 km2 of 3D CSEM surveys acquired for hydrocarbon exploration from 2007 to 2019. High-quality MT data are extracted for periods ranging from 0.5 s to 5000 s. The data show no apparent contamination by the active source nor effects related to large time-gaps in data collection and variable solar activity. Along receiver profiles, abrupt lateral variations of apparent resistivity and phase trends coincide with major structural boundaries and underline the geological information contained in the data. Dimensionality analysis reveals a dichotomy between the western domain of the SW Barents Sea, dominated by a single N-S electromagnetic strike, and the eastern domain, with a two-fold, period-dependent strike. 35 receivers show 3D distortion caused by nearby bathymetric slopes, evidenced by elevated skew values. We delineate geographical areas where the 2D assumption is tenable and lay the foundation for future MT modelling strategies in the SW Barents Sea. We performed 2D MT inversion along one of the regional transects, a ∼220 km-long, E-W profile encompassing a major structural high and sedimentary basin approaching the continent-ocean transition. The resistivity model reveals low crustal resistivity values (1–10 Ω.m) beneath the deep sedimentary basins, in marked contrast with high resistivity values (1000–5000 Ω.m) of the thick crystalline crust on the structural high. We interpret this abrupt lateral resistivity variation as a rapid transition from a thick, dry continental crust to a hyperextended and hydrated crustal domain. Integration of resistivity with seismic velocity, density and magnetic susceptibility models may further refine these structural models and the underlying tectonic processes in the SW Barents Sea margin. Our methodology is applicable globally where 3D CSEM surveys are acquired and has a large potential for harvesting new knowledge on the electrical resistivity properties of the lithosphere.

Beschreibung: SUMMARY Curie point depth can be used as a proxy for plate temperatures. Data from the North Atlantic (10°–50°N) are used here to determine if the observed oscillations and patterns in Curie depths could be a subproduct of small-scale thermal instabilities arising at the bottom of the lithospheric plates. Our numerical models suggest that small-scale convection (SSC) cells could produce thermal perturbations at isotherms as low as the Curie point. These results are compatible with North Atlantic observations in terms of wavelengths (150–300 km), amplitudes (∼4 km) and orientations of the instabilities. Observed Curie-point depth oscillations before the onset (70 to 90 Myr) of SSC could also be linked to other different processes. We suggest that, in the case of the North Atlantic lithosphere, the spreading rate variation and the melt and upwelling could be intricately linked and cause a different pattern of SSC.

Beschreibung: SUMMARY We present palaeo- and rock magnetic results from a well-dated, 21 m-thick, Late Pleistocene continental sedimentary section located in southern Germany. Rock magnetic measurements reveal a complex magnetic mineralogy dominated by low coercivity minerals likely related to single domain biogenic magnetite and biogenic or early diagenetic greigite. In the lower part of the section also detrital haematite is present. The stable remanence shows predominantly normal polarity with two marked deviations at ∼1280-1200 cm and at 886 cm profile depth. Whereas the lower excursion is well established by several samples and documented also by detrital haematite, the upper one is only represented by a single sample and revealed by magnetite and greigite. Using the radiocarbon-based age model for the section, the lower excursion yields an age of 42.8–41.3 ka cal BP and is interpreted to represent the Laschamps geomagnetic excursion. The increased abundance of greigite in the upper part of the section, especially in the sample responsible for the upper anomalous direction, renders the interpretation of an actual excursion problematic due to the reducing environment necessary for the greigite formation.

Beschreibung: SUMMARY SPiRaL is a joint global-scale model of wave speeds (P and S) and anisotropy (vertical transverse isotropy, VTI) variations in the crust and mantle. The model is comprised of 〉2.1 million nodes with five parameters at each node that capture velocity variations for P- and S-waves travelling at arbitrary directions in transversely isotropic media with a vertical symmetry axis (VTI). The crust (including ice, water, sediments and crystalline layers) is directly incorporated into the model. The default node spacing is approximately 2° in the lower mantle and 1° in the crust and upper mantle. The grid is refined with ∼0.25° minimum node spacing in highly sampled regions of the crust and upper mantle throughout North America and Eurasia. The data considered in the construction of SPiRaL includes millions of body wave traveltimes (crustal, regional and teleseismic phases with multiples) and surface wave (Rayleigh and Love) dispersion. A multiresolution inversion approach is employed to capture long-wavelength heterogeneities commonly depicted in global-scale tomography images as well as more localized details that are typically resolved in more focused regional-scale studies. Our previous work has demonstrated that such global-scale models with regional-scale detail can accurately predict both teleseismic and regional body wave traveltimes, which is necessary for more accurate location of small seismic events that may have limited signal at teleseismic distances. SPiRaL was constructed to predict traveltimes for event location and long-period waveform dispersion for seismic source inversion applications in regions without sufficiently tuned models. SPiRaL may also serve as a starting model for full-waveform inversion (FWI) with the goal of fitting waves with periods 10–50 s over multiple broad regions (thousands of kilometres) and potentially the globe. To gain insight to this possibility, we simulated waveforms for a small set of events using SPiRaL and independent waveform-based models for comparison. For the events tested, the performance of the traveltime-based SPiRaL model is shown to be generally on par with regional 3-D waveform-based models in three regions (western United States, Middle East, Korean Peninsula) suggesting SPiRaL may serve as a starting model for FWI over broad regions.

Beschreibung: SUMMARY Simulating poroelastic waves in large-scale 3-D problems having porous media coupled with elastic solids and fluids is computationally challenging for traditional methods. It is well established that the spectral element method (SEM) is more effective than the traditional methods like the finite element method (FEM) when dealing with complex geophysical problems, for its high-order accuracy with exponential convergence. However, at present, little research has been done for SEM in the frequency domain, which will be more efficient than the time-domain SEM for narrowband simulations with multiple sources, material dispersion and attenuation. Herein, we systematically develop a SEM in the frequency domain to simulate coupled poroelastic, elastic and acoustic waves in anisotropic (i.e. porosity, permeability and elastic coefficients with anisotropy), heterogeneous, and lossy media. Furthermore, we completely remove the dimension inconsistency between the displacement field and the pressure in porous media to reduce the condition number of the system matrix by around 16 orders of magnitude while maintaining the symmetry of the system matrix. To solve the multiphysics coupling problems, we apply different coupling conditions to different interface types, and use basis functions to discretize the corresponding governing equations. Numerical examples show that the proposed SEM can obtain higher accuracy with much fewer unknowns compared with the FEM and has the capacity to solve the large-scale real coupling problems.

Beschreibung: Neopterin (NP), biopterin (BP) and monapterin (MP) exist in saliva. The physiological role of salivary NP as well as the pathophysiological role of increased NP in the immune-activated state has been unclear. Saliva is a characteristic specimen different from other body fluids. In this study, we analysed salivary NP and related pterin compounds, BP and MP and revealed some of its feature. High-performance liquid chromatography (HPLC) analysis of saliva and plasma obtained from 26 volunteers revealed that salivary NP existed mostly in its fully oxidized form. The results suggested that salivary NP as well as BP would mostly originate from the oral cavity, perhaps the salivary glands, and that salivary NP levels might not reflect those in the plasma. We also found that a gender difference existed in correlations between concentrations of salivary total concentrations of NP (tNP) and BP (tBP). HPLC analysis of saliva obtained from 5 volunteers revealed that the concentrations of salivary tNP as well as tBP fluctuated in an irregular fashion in various individuals. MP, a diastereomer of NP, might have come from oral cavity NP itself or its precursor. These results indicated that the nature of salivary NP might be different from that of NP in the blood or urine.

Beschreibung: Background Suicide rates are up to 4 times greater in cancer compared with the general population, yet best practices for institutional suicide prevention are unknown. The objective of this study was to examine the association between suicide risk screening (SRS), clinician response, and suicide mortality at a comprehensive cancer treatment center. Methods We conducted a naturalistic, retrospective cohort study of patients attending the Princess Margaret Cancer Centre, where routine screening for suicidal intent within the Distress Assessment and Response Tool (DART-SRS) was implemented in 2010. Inverse probability of treatment weighting was used to evaluate the impact of DART-SRS completion on suicide mortality from 2005 to 2014. Chart audits were conducted for clinician response to suicidality, and crude suicide rates over the study period were analyzed. All statistical tests were 2-sided. Results Among 78 650 cancer patients, 89 (0.1%) died by suicide, of whom only 4 (4.5%) had completed DART-SRS. Among DART-SRS completers (n = 14 517), 69 (0.5%) reported suicidal intent, none of whom died by suicide. DART-SRS completion was associated with increased clinician response to suicidality (17.4% vs 6.7%, P = .04), more psychosocial service usage (30.5% vs 18.3%, P 

Beschreibung: SUMMARY Compared with surface waves, guided waves are rarely applied in near-surface investigation. The main reason may lie in the complexity of their dispersion curves. Besides, the study and understanding of guided wave dispersion characteristics are now also inadequate and not deep enough. In this paper, we derived the complete theoretical dispersion curves of P–SV-wave and pure P-wave systems in layered media based on the transmission matrix method and obtained the relative displacement amplitude coefficients at the free surface as a function of frequency and phase velocity for both surface and guided waves. By assigning the value of relative displacement amplitude coefficient to the corresponding point (f,v) on dispersion curve, we got a multi-information diagram called relative amplitude dispersion map (RADM). As a unified description of surface and guided waves, RADM not only shows the velocity–frequency relationship but also represents the polarized energy ratio at the free surface by display colours. The accuracy of RADM was proved by synthetic seismic records, in which RADMs fit well with the corresponding dispersion energy of surface and guided waves. In addition, we designed six models with different Poisson's ratio (PR) and different layer numbers for comparison. It shows that the dispersive vertical-to-horizontal amplitude ratio of guided waves is complex and discontinuous in RADM, which brings great difficulty for mode identification and even affects the subsequent inversion. Tests also show that for high PR layers, the trends of guided P–SV-wave dispersion curves are basically consistent with those of pure P wave. With the decrease of PR, dispersion curves of guided P–SV wave gradually deviate from those of pure P wave. However, RADMs can be greatly consistent with the dispersion energy in either case. This is of great significance for the inversion of near-surface P and S velocities by using dispersion relationships of multimode surface and guided waves.

Beschreibung: SUMMARY This study examines local geopotential field modelling over a mountainous region in Tanzania using vector airborne gravity data. We use the adjusted spherical cap and rectangular harmonic analyses. Both methods are based on expansion of gravitational potential into a series of orthogonal harmonic basis functions of local support in such a way that the expansion coefficients are determined by gravity observations. All three components of gravity vector are simultaneously inverted to derive the geopotential coefficients. In order to evaluate the accuracy of the local models, independent checkpoints are selected within the study region and around its boundary and the computed gravity vectors are compared with the independent gravity observations. The results show an excellent agreement with root mean square error (RMSE) of 

Beschreibung: SUMMARY The vast majority of teleseismic XKS (including SKS, SKKS and PKS) shear wave splitting studies interpret the observed splitting parameters (fast orientation and splitting time) based on the assumption of a spatially invariant anisotropy structure in the vicinity of a recording station. For such anisotropy structures the observed splitting parameters are either independent of the arriving azimuth of the seismic ray paths if the medium traversed by the ray paths can be represented by a single layer of anisotropy with a horizontal axis of symmetry (i.e. simple anisotropy), or demonstrate a periodic variation with respect to the arriving azimuth for a more complicated structure of anisotropy (e.g. multiple layers with a horizontal axis of symmetry, or a single layer with a dipping axis). When a recording station is located near the boundary of two or more regions with different anisotropy characteristics, the observed splitting parameters are dependent on the location of the ray piercing points. Such a piercing-point dependence is clearly observed using a total of 360 pairs of XKS splitting parameters at three stations situated near the northeastern edge of the Sichuan Basin in central China. For a given station, the fast orientations differ as much as 90°, and the azimuthal variation of the fast orientations lacks a 90° or 180° periodicity which is expected for double-layered or dipping axis anisotropy. The observed splitting parameters from the three stations are spatially most consistent when they are projected at a depth of ∼250 km, and can be explained by shear strain associated with the absolute plate motion and mantle flow deflected by the cone-shaped lithospheric root of the Sichuan Basin.

Beschreibung: SUMMARY The Gravity Recovery and Climate Experiment (GRACE) mission has been providing abundant information regarding the mass changes of the Earth in terms of time-series of temporal gravity field models since 2002. To derive temporal gravity field models with high accuracy, many methods have been developed. In this paper, we focus on the variational equation integration approach. The main works can be summarized as follows: (1) analysing the quality of GRACE Level1B RL02 and RL03 data, including accelerometer observations (ACC1B), star camera measurements (SCA1B) and K-Band low-low Satellite-to-Satellite Tracking (SST) range-rate (KBRR) data (KBR1B); (2) discussing the influence of arc-specific parameters and arc length on gravity field recovery and (3) comparing two different methods used for sensitivity matrix generation, namely, a numerical integration method and the method of variation of constants, from the perspectives of accuracy and efficiency, respectively. Based on these analyses, discussions and comparisons, a new time-series of GRACE monthly gravity field models in terms of spherical harmonic coefficients completed to degree and order 60, called SWJTU-GRACE-RL02p, was derived by using the modified variational equation integration approach bashed on GRACE Level1B RL03 data, covering the period from April 2002 to October 2011 with some gaps in between due to poor quality or missing GRACE data. Thus we are looking at the results some 10yrs in the past. The differences between the traditional variational equation integration approach and the approach that we used are mainly as follows: (1) according to the GRACE data quality, the arc length is no longer a constant in the determination of temporal gravity field models; (2) the kinematic empirical parameters, which are mainly designed to remove the bias and drifts in KBRR residuals, are abandoned and (3) the method of variation of constants developed at the Astronomical Institute of the University of Bern (AIUB) and used to solve the system of variational equations associated with constrained pulses and piecewise constant accelerations is used to calculate the sensitivity matrices of accelerometer bias parameters to improve the calculation efficiency and ensure the calculation accuracy. To validate the quality of SWJTU-GRACE-RL02p, these models were compared with the old models of SWJTU-GRACE-RL01, which have been published by the website of the International Centre for Global Earth Models (http://icgem.gfz-potsdam.de/series), and the official products [i.e. the RL05 and RL06 versions of GRACE LEVEL2 at the Centre for Space Research (CSR), Jet Propulsion Laboratory (JPL) and GeoForschungsZentrum (GFZ)]. Compared to the RL06 version of official models, the models of SWJTU-GRACE-RL02p present competitive performance for global mass changes. Furthermore, these models show less noise and a higher signal strength over some local areas with large mass changes than the models of SWJTU-GRACE-RL01. The comparisons between SWJTU-GRACE-RL02p and a variety of other models including official models, GLDAS, models provided by EGSIEM and daily solutions released by ITSG indicate that our approach and the data processing details presented in this paper provide an alternative strategy for the recovery of temporal gravity field models from GRACE-type data.

Beschreibung: SUMMARY The analysis of multistation surface wave records is of increasing popularity in imaging the structure of the Earth due to its robustness on dispersion measurement. Since the representation of multistation surface wave dispersion curves (DCs) is uncertain in laterally varying media, average information beneath the receiver array is assumed to be obtained by inverting the dispersion curves with a horizontally layered model. To retrieve a more realistic 2-D laterally varying structure, we present a multiscale window analysis of surface waves (MWASW) method for analysing 2-D active-source surface wave data. The MWASW method is based on the use of a forward algorithm for calculating the theoretical DCs over 2-D models and multisize spatial windows for estimating the dispersion data. The forward algorithm calculates the theoretical dispersion considering the lateral variation beneath the receiver array; hence, the estimated DC is not treated as representative of the average properties but as data containing the lateral variation information. By inverting the dispersion data extracted from different spatial windows, the subsurface information at different depth ranges and lateral extensions are integrated to produce a shear wave velocity model. The dispersion curves analysed from smaller spatial windows retrieve the shallow structure with a higher lateral resolution, whereas the phase velocity data from larger spatial windows provide average information with a greater depth. We test the effectiveness of the MWASW method using three synthetic examples and two field data sets. Both results show the improved lateral resolution of the S-wave velocity structure retrieved with the MWASW method compared to the traditional multistation method in which the local horizontally layered model is adopted.

Beschreibung: SUMMARY As 3-D geological models become more numerous and widely available, the opportunity arises to combine them into large regional compilations. One of the biggest challenges facing these compilations is the connection and alignment of individual models, especially in less explored areas or across political borders. In this regard, gravity modelling is suitable for revealing additional subsurface information that can support a harmonization of structural models. Here, we present an integrated geological and gravity modelling approach to support the harmonization process of two geological 3-D models of the North German Basin in the cross-border region between the federal states of Saxony-Anhalt and Brandenburg. Gravity gradient calculation, filtering and Euler deconvolution are utilized to reveal new insights into the local fault system and gravity anomaly sources. The independent models are merged and harmonized during 3-D forward and inverse gravity modelling. Herein, density gradients for individual layers are incorporated in the framework of model parametrization. The resulting geological 3-D model consists of harmonized interfaces and is consistent with the observed gravity field. To demonstrate the plausibility of the derived model, we discuss the new geophysical findings on the sedimentary and crustal structures of the cross-border region in the context of the regional geological setting. The cross-border region is dominated by an NW–SE oriented fault system that coincides with the Elbe Fault System. We interpret a low-density zone within the basement of the Mid-German Crystalline Rise as a northward continuation of the Pretzsch–Prettin Crystalline Complex into the basement of the North German Basin. Additionally, we observe two types of anticlines within the basin, which we link to provinces of contrasting basement rigidity. Our gravity modelling implies that the Zechstein salt has mostly migrated into the deeper parts of the basin west of the Seyda Fault. Finally, we identify a pronounced syncline that accommodates a narrow and up to 800 m deep Cenozoic basin.

Beschreibung: Background We hypothesized that the addition of receptor tyrosine kinase inhibitors (RTKis, e.g., lapatinib, erlotinib, cetuximab, bevacizumab, panitumumab) to radiotherapy-based treatment for solid tumors does not increase overall survival but may increase toxicity. Methods Population, Intervention, Control, Outcome, Study Design; Preferred Reporting Items for Systematic Reviews and Meta-Analyses; and Meta-analysis of Observational Studies in Epidemiology methods were used to identify prospective randomized studies including patients with solid tumor cancers treated with radiotherapy with or without RTKis. Extracted variables included use of radiotherapy vs chemoradiotherapy, RTKi type (antibody vs small molecule), outcomes, and toxicities. The primary endpoint was overall survival; the secondary endpoint was grade 3+ toxicity. Random-effects meta-analyses were performed for each outcome measure. All statistical tests were 2-sided. Results A total of 405 studies met the initial search criteria, of which 13 prospective randomized trials of radiotherapy with or without RTKi met the inclusion criteria, encompassing 5678 patients. The trials included cancers of the head and neck (6 trials, 3295 patients), esophagus (3 trials, 762 patients), lung (2 trials, 550 patients), and brain (2 trials, 1542 patients). Three studies evaluated a small molecule and radiotherapy in 949 patients, and 10 studies evaluated antibodies and radiotherapy in 4729 patients. The addition of RTKis to radiotherapy-based treatment did not improve overall survival (hazard ratio = 1.02, 95% confidence interval = 0.90 to 1.15, P = .76) but increased grade 3+ toxicity (relative risk = 1.18, 95% confidence interval = 1.06 to 1.33, P = .009). Conclusions The addition of RTKis to radiotherapy does not improve survival and worsens toxicity.

Beschreibung: SUMMARY Accurate picking of head-wave arrival times is an important component of first-arrival traveltime tomography. Far-offset traces in particular have low signal-to-noise ratio (SNR), but picking on these traces is necessary in order to obtain velocity information at depth. Furthermore, there is often an insufficient number of far-offset traces for obtaining reliable models at depth. We present here an extrapolation method for increasing the number of first arrivals beyond the maximum recorded offset, thereby extending the supervirtual refraction interferometry (SVI) method. We refer to the method as extrapolated SVI (ESVI). It is a novel attempt to extrapolate first arrivals using a fully data-driven method. We first test the methodology on synthetic data sets, and we then apply ESVI to two published real data sets over the Pärvie fault system in northern Sweden. These data sets were acquired along the same profile at different times with different acquisition parameters and noise levels. The results show that ESVI enhances the SNR of head waves when the noise level is high. That is the same as the conventional SVI. ESVI also increases the number of pickable first arrivals by extrapolating head waves past the original maximum offset of each shot. We also show that the significant increase in first-arrival traveltime picks is beneficial for improving resolution and penetration depth in the tomographic imaging and, consequently, better revealing the subsurface velocity distribution. The tomographic images show higher velocities in the hanging walls of the main Pärvie fault and another subsidiary fault, as interpreted relative to migrated images from previous seismic reflection processing.

Beschreibung: Background This study projected the number of metastatic breast cancer (mBC) cases and costs (medical and productivity) attributable to mBC through 2030 among 3 age groups: younger (aged 18-44 years), midlife (aged 45-64 years), and older women (aged 65 years and older). Methods We developed a stock/flow model in which women enter the mBC population at initial diagnosis (de novo stage IV) or through progression of an earlier-stage cancer. Women exit the mBC population through death. Input parameters by age and phase of treatment came from the US Census, Surveillance, Epidemiology, and End Results and peer-reviewed literature. Results In 2030, we estimated there would be 246 194 prevalent cases of mBC, an increase of 54.8% from the 2015 estimate of 158 997. We estimated total costs (medical and productivity) of mBC across all age groups and phases of care were $63.4 billion (95% sensitivity range = $59.4-$67.4 billion) in 2015 and would increase to $152.4 billion (95% sensitivity range = $111.6-$220.4 billion) in 2030, an increase of 140%. Trends in estimated costs were higher for younger and midlife women than for older women. Conclusions The cost of mBC could increase substantially in the coming decade, especially among younger and midlife women. Although accounting for trends in incidence, progression, and survival, our model did not attempt to forecast structural changes such as technological innovations in breast cancer treatment and health-care delivery reforms. These findings can motivate early detection activities, direct value-driven mBC treatment, and provide a useful baseline against which to measure the effect of prevention and treatment efforts.

Beschreibung: Background The US Food and Drug Administration (FDA) introduced an Accelerated Approval (AA) pathway to expedite patient access to new drugs. AA accepts less rigorous trial designs, including single-arm studies (SAS), owing to perceived lack of feasibility of timely randomized controlled trials (RCTs). Methods We designed hypothetical RCTs with endpoints of overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) for FDA approvals based on SAS for solid tumors during 2010-2019. Existing standards of care served as controls. RCTs were designed to detect a difference with power of 0.80, α-error of 5% (2-sided), and 1:1 randomization. Accrual duration was estimated based on participation by less than 5% of eligible patients derived from cancer-specific incidence and mortality rates in the United States. Results Of 172 (18.0%) approvals during the study period, 31 (18.0%) were based on SAS. Median sample size was 104 (range = 23-411), and 77.4% were AA. All studies reported ORR, 55% reported duration of response, 19.4% reported PFS, and 22.5% reported OS. Median sample sizes needed to conduct RCTs with endpoints of ORR, PFS, and OS were 206, 130, and 396, respectively. It would have been theoretically possible to conduct RCTs within duration comparable with that required by SAS for 84.6%, 94.1%, and 80.0% of approvals with endpoints of ORR, PFS, and OS, respectively. Conclusion An overwhelming majority of FDA approvals based on SAS should be feasible as RCTs within a reasonable time frame. Given the collateral harms to patients and to scientific rigor, drug approval based on SAS should only be permitted under exceptional circumstances.

Beschreibung: SUMMARY Natural gas can be temporarily stored in a variety of underground facilities, such as depleted gas and oil fields, natural aquifers and caverns in salt rocks. Being extensively monitored during operations, these systems provide a favourable opportunity to investigate how pressure varies in time and space and possibly induces/triggers earthquakes on nearby faults. Elaborate and detailed numerical modelling techniques are often applied to study gas reservoirs. Here we show the possibilities and discuss the limitations of a flexible and easily formulated tool that can be straightforwardly applied to simulate temporal pore-pressure variations and study the relation with recorded microseismic events. We use the software POEL (POroELastic diffusion and deformation) which computes the poroelastic response to fluid injection/extraction in a horizontally layered poroelastic structure. We further develop its application to address the presence of vertical impermeable faults bounding the reservoir and of multiple injection/extraction sources. Exploiting available information on the reservoir geometry and physical parameters, and records of injection/extraction rates for a gas reservoir in southern Europe, we perform an extensive parametric study considering different model configurations. Comparing modelled spatiotemporal pore-pressure variations with in situ measurements, we show that the inclusion of vertical impermeable faults provides an improvement in reproducing the observations and results in pore-pressure accumulation near the faults and in a variation of the temporal pore-pressure diffusion pattern. To study the relation between gas storage activity and recorded local microseismicity, we applied different seismicity models based on the estimated pore-pressure distribution. This analysis helps to understand the spatial distribution of seismicity and its temporal modulation. The results show that the observed microseismicity could be partly linked to the storage activity, but the contribution of tectonic background seismicity cannot be excluded.

Beschreibung: SUMMARY Seismic and geodetic examinations of the Hikurangi subduction zone (HSZ) indicate a remarkably diverse and complex system. Here, we investigate the 3-D P-wave velocity structure of the HSZ by applying an iterative, nested regional-global tomographic algorithm. The new model reveals enhanced details of seismic variations along the HSZ. We also relocate over 57 000 earthquakes using this newly developed 3-D model and then further improve the relative locations for 75 per cent of the seismicity using waveform cross-correlation. Double seismic zone characteristics, including occurrence, depth distribution and thickness change along the strike of the HSZ. An aseismic but fast Vp zone separates the upper and lower planes of seismicity in the southern and northern North Island. The upper plane of seismicity correlates with low Vp zones below the slab interface, indicating fluid-rich channels formed on top and/or within a dehydrated crust. A broad low Vp zone is resolved in the lower part of the subducting slab that could indicate hydrous mineral breakdown in the slab mantle. In the northern North Island and southern North Island, the lower plane of seismicity mostly correlates with the top of these low Vp zones. The comparison between the thermal model and the lower plane of seismicity in the northern North Island supports dehydration in the lower part of the slab. The mantle wedge of the Taupo volcanic zone (TVZ) is characterized by a low velocity zone underlying the volcanic front (fluid-driven partial melting), a fast velocity anomaly in the forearc mantle (a stagnant cold nose) and an underlying low velocity zone within the slab (fluids from dehydration). These arc-related anomalies are the strongest beneath the central TVZ with known extensive volcanism. The shallow seismicity (

Beschreibung: The lipid-rich calanoid copepod, Calanus finmarchicus, plays a critical role in the Gulf of Maine pelagic food web. Despite numerous studies over the last several decades, a clear picture of variability patterns and links with key environmental drivers remains elusive. This study applies model-based scaling and sensitivity analyses to a regional plankton dataset collected over the last four decades (1977–2017). The focus is to describe the gulf-wide spatio-temporal patterns across three major basins, and to assess the relative roles of internal population dynamics and external exchanges. For the spring stock, there is strong synchrony of interannual variability among three basins. This variability is largely driven by internal population dynamics rather than external exchanges, and the internal population dynamics are more sensitive to the change of top-down mortality regime than the bottom-up forcings. For the fall stock, the synchrony among basins weakens, and the variability is influenced by both internal mortality and external dilution loss. There appears to be no direct connection between the spring stock with either the preceding or subsequent fall stock, suggesting seasonal or sub-seasonal scales of population variability and associated drivers. The results highlight seasonally varying drivers responsible for population variability, including previously less recognized top-down control.

Beschreibung: Mafic intrusions on the NE shoulder of the Midcontinent Rift (Keweenawan LIP), including Cu–PGE mineralized gabbros within the Coldwell Complex (CC), and rift parallel or radial dykes outside the CC are correlated based on characteristic trace element patterns. In the Coldwell Complex, mafic rocks are subdivided into four groups: (1) early metabasalt; (2) Marathon Series; (3) Layered Series; (4) Geordie–Wolfcamp Series. The Marathon Series are correlated with the rift radial Abitibi dykes (1140 Ma), and the Geordie–Wolfcamp Series with the rift parallel Pukaskwa and Copper Island dykes. U–Pb ages determined for five gabbros from the Layered and Marathon Series are between 1107·7 and 1106·0 Ma. Radiogenic isotope ratios show near chondritic (CHUR) εNd(1106 Ma) and 87Sr/86Sri values that range from –0·38 to +1·13 and 0·702537 to 0·703944, respectively. Distinctive geochemical properties of the Marathon Series and Abitibi dykes, such as Ba/La (14–37), Th/Nb (0·06–0·12), La/Sm (3·8–7·7), Sr/Nd (21–96) and Zr/Sm (9–19), are very different from those of the Geordie–Wolfcamp Series and a subset of Copper Island and Pukaskwa dykes with Ba/La (8·7–11), Th/Nb (0·12–0·13), La/Sm (6·7–7·9), Sr/Nd (5–7·8) and Zr/Sm (18–24). Each unit exhibits covariation between incompatible element ratios such as Zr/Sm and Nb/La or Gd/Yb, Sr/Nd and Ba/La, and Nb/Y and Zr/Y, which are consistent with mixing relationship between two or more mantle domains. These characteristics are unlike those of intrusions on the NW shoulder of the MCR, but resemble those of mafic rocks occurring in the East Kenya Rift. The results imply that an unusual and long-lived mantle source was present in the NE MCR for at least 34 Myr (spanning the 1140 Ma Abitibi dykes and the 1106 Ma Marathon series) and indicate potential for Cu–PGE mineralization in an area much larger than was previously recognized.

Beschreibung: The Barents Sea and its marine ecosystem is exposed to many different processes related to the seasonal light variability, formation and melting of sea-ice, wind-induced mixing, and exchange of heat and nutrients with neighbouring ocean regions. A global model for the RCP4.5 scenario was downscaled, evaluated, and combined with a biophysical model to study how future variability and trends in temperature, sea-ice concentration, light, and wind-induced mixing potentially affect the lower trophic levels in the Barents Sea marine ecosystem. During the integration period (2010–2070), only a modest change in climate variables and biological production was found, compared to the inter-annual and decadal variability. The most prominent change was projected for the mid-2040s with a sudden decrease in biological production, largely controlled by covarying changes in heat inflow, wind, and sea-ice extent. The northernmost parts exhibited increased access to light during the productive season due to decreased sea-ice extent, leading to increased primary and secondary production in periods of low sea-ice concentrations. In the southern parts, variable access to nutrients as a function of wind-induced mixing and mixed layer depth were found to be the most dominating factors controlling variability in primary and secondary production.

Beschreibung: Miocene magmatic rocks are exposed as lava flows (OKV group), subvolcanic rocks (SRG group), and as lavas interbedded with shallow-basin sedimentary layers (TVN group) in the Takab area, NW Iran. Zircon U–Pb dating yields ages of 18 to 15 Ma. Whole-rock chemistry shows that most of the Early Miocene magmatic rocks are andesite with subordinate dacite. The magmatic rocks have low contents of MgO, Ni, Cr, Ti, Nb and Ta, and high concentrations of Li, large ion lithophile elements such as Rb, K and Ba, and light rare earth elements. The OKV and SRG groups have similar initial 87Sr/86Sr ratios (0·70557–0·70768) and εNd(t) values (+1·0 to +2·2). The TVN group show larger variations of 87Sr/86Sr(i) ratios from 0·70628 to 0·71033 and εNd(t) values from –3·8 to +1·6. This implies a greater role of involvement of supra-crustal domains in the evolution of the TVN group relative to the SRG and OKV groups. Early Miocene magmatic rocks in the Takab area are situated between the Sanandaj–Saqqez Cretaceous calc-alkaline andesite in the SW and the Late Eocene–Oligocene (35–27 Ma) ocean island basalt-like Mianeh–Hashtrood magmatic belt of possible back-arc affinity in the NE. In addition, Late Eocene (40–37 Ma) syn-collision granites in the Baneh–Marivan area along the Zagros suture zone along the west side of the Sanandaj–Saqqez Cretaceous calc-alkaline andesite body indicate that collision of the Arabian Plate and the NW Iran Block occurred in the Late Eocene. These observations support the idea that Early Miocene andesites (18–15 Ma) in the Takab area were generated after collision, which was also associated with doubling of the thickness of the continental crust in the Zagros suture zone, thinning of continental crust far from the Zagros suture zone, and development of shallow-basin sedimentary rocks in NW Iran. Partial melting of mafic calc-alkaline bodies at depth or highly metasomatized fossil mantle owing to thinning of continental crust and asthenospheric upwelling may represent possible sources for the Late Miocene andesite. We conclude that andesitic rocks, even with typical arc signatures, are not always generated in an active margin and that some were probably generated in a post-collision tectonic regime. Misinterpretation of the arc signature can result in erroneous assumptions as to the geodynamic regime, and in the particular case of NW Iran, the timing of collision of the Arabian and Iranian plates.

Beschreibung: Background Physical activity and exercise improve function, symptom control, and health-related quality of life (QoL) for many cancer survivors; however, the evidence is limited and inconsistent in lung cancer. We examined the relationship between leisure-time physical activity (LTPA) and health-related QoL in a national sample of US lung cancer survivors. Methods We conducted a cross-sectional study using the Centers for Disease Control and Prevention Behavioral Risk Factor Surveillance System. We defined LTPA as a self-report of engaging in any physical activity or exercise such as running, calisthenics, golf, gardening, or walking for exercise in the past 30 days, health-related QoL as the number of days of having poor physical or mental health in the past 30 days, and general health status. We analyzed using multivariable logistic regressions with 95% confidence intervals (CIs). Results Among 614 lung cancer survivors, 316 (51.5%) reported engaging in LTPA. The counts (and proportions) of participants who engaged in LTPA vs no LTPA were, respectively, 135 (42.7%) vs 63 (21.1%) for 0 days of poor physical health, 222 (70.3%) vs 174 (58.4%) for 0 days of poor mental health, and 158 (50.0%) vs 77 (25.8%) for good to excellent general health. In multivariable analyses, participating in LTPA was associated with odds ratios of 2.64 (95% CI = 1.76 to 3.96) and 1.43 (95% CI = 0.97 to 2.10) for 0 days of poor physical and mental health, respectively, and 2.61 (95% CI = 1.74 to 3.91) for good to excellent general health. Conclusions Participating in LTPA was associated with improved health-related QoL. Interventions to promote LTPA and/or exercise-based rehabilitation may improve QoL among lung cancer survivors.

Beschreibung: Summary Single-station and array ambient vibration techniques are widely used in onshore environments, in particular to retrieve the subsurface structure and shear-wave velocity profiles. We apply these techniques offshore in Lake Lucerne (Switzerland) using single-station and array Ocean Bottom Seismometer (OBS) data. This lake has experienced tsunamigenic subaquatic slope failures in the past and still has sediment-charged slopes that might fail in the presence of a seismic or aseismic trigger. The application of traditional onshore methods offshore brings additional challenges related to the processing of recorded data. To overcome these challenges, we perform multibeam bathymetry surveys to precisely locate the OBS on the lake floor and airgun shootings to determine the orientation of the horizontal components of the seismometer and to correct the time drift of the recorder. Then we obtain surface-wave phase velocity dispersion curves of Scholte and Love waves, and Scholte wave ellipticity curves at six subaquatic slopes. After the estimation of the dispersion curves, we deal with their modal identification using mode attribution analysis. The shear-wave velocity and thickness of the sedimentary layers at the investigated slopes are inferred using a transdimensional Bayesian inversion algorithm. The resolved velocity profiles show very low shear-wave velocities in shallow lake sediments and allow us to improve the understanding of the local stratigraphy. This research contributes to the assessment of stability and tsunamigenic potential of subaquatic slopes in Lake Lucerne.

Beschreibung: SUMMARY Gravity monitoring might require observation of temporal changes of gravity below the nanometre per second squared (nm s−2) level, which can be achieved by precise isolation of the signal of interest from all other disturbing effects. One method of signal isolation is elimination of disturbing effects by taking the difference between gravity changes measured simultaneously using two gravimeters installed close together. Herein, we describe differences in temporal gravity changes below the nm s−2 level in the tidal frequency bands as observed through simultaneous measurements taken with three superconducting gravimeters (SGs) located 80, 93 and 94 m from the coastline in Tomakomai, Hokkaido, northern Japan. Those changes are consistent with differences in ocean tide loading effects on gravity at the SG locations computed using the software package GOTIC2, which uses a highly accurate land–sea boundary and ocean tide model near our site. The observed ocean tide loading differences were found to result from Newtonian attraction of the ocean tide mass within an angular distance of 0.003° from the SG locations. This result suggests that coastal observations of differential tidal gravity variations at different distances from the coast help to validate ocean tide loading computation models in the immediate vicinity of the SG stations. This method enables observation of non-periodic gravity changes occurring below the nm s−2 level over a few hours. Its salient benefit is that rapid and simple observation can be achieved without long-term continuous measurements, which is necessary for observing that level of gravity change with only one SG.

Beschreibung: SUMMARY The separation of regional-residual anomalies plays an important role in the processing of potential field anomalies for obtaining better understandings of the nature of the underground sources. Many methods have been developed to achieve the separation of anomalies that are of distinct wavelengths. On the other hand, fewer studies have addressed the separation of local anomalies from the observed potential field anomalies. In this paper, we introduce a new process for separating localized anomalies from the observations under the Cartesian and spherical coordinates. The separation is achieved using the equivalent source technique and an iterative inversion process which is to refine and finalize the separated local anomalies. Additionally, we introduce an inversion method for determining the equivalent sources that are of varying dimensions, as well as a quantitative measurement to assess the accuracy of the separation process. Verified with synthetic examples, the proposed method could extract arbitrary shaped local anomalies from the rest with low error levels. Subsequently, we apply the method to the construction of a 3-D model of the mantle uplift beneath the Von Kármán crater (VKC) on the Moon. The VKC is the landing site of the Chinese lunar exploration mission Chang'e 4, which lies in the northwestern portion of the South-Pole Aitken (SPA) basin on the far side of the Moon. Multiple generations of mare basalts are identified within the VKC, which indicates a complex geological history of the basin. Insights into the evolutionary history of this region can be obtained by investigating the deep crustal structure of the VKC using topographic and gravity data. Processed with the proposed method, the 3-D structure we obtain provides evidence for separated mantle uplifting events triggered by the two impact events that created the VKC and the Von Kármán M crater, respectively.

Beschreibung: Summary High-rate Global Navigation Satellite System (GNSS) has emerged as an effective method to recover seismic waveforms without saturation and drifts, but it has the limitation of relatively lower sampling rate and higher noise level compared to seismic instruments. In this study, we present a new seismogeodetic method by integrating GNSS and accelerometer data to obtain optimal real-time seismic waveforms. Unlike traditional integration methods based on GNSS techniques of relative positioning or precise point positioning, the new method uses a GNSS time difference technique and inherits its unique advantage in real-time and high-accuracy velocity solutions. Furthermore, by incorporating the tightly coupled structure, it can overcome the cascading problem and provide more accurate and robust waveforms compared to its loosely coupled counterpart. The performance of this method is first compared with the traditional loosely coupled approach in challenging environments through a set of shake table experiments. With three GNSS satellites, this approach method can improve the accuracy of velocities and displacements by 42 per cent and 87 per cent, respectively. With four or more GNSS satellites, the average improvements of the method reach 25 per cent and 41 per cent for the velocities and displacements, respectively. We then validate the full performances of the method through simulated shake table experiments and collocated GNSS and accelerometer data during the 2016 Mw6.6 central Italy earthquake. The simulated and real-event analyses demonstrate that the new integration method can take full advantage of the complementary characteristics of GNSS and accelerometer sensors. By providing more accurate and broadband velocity and displacement waveforms in a real-time or near-real-time manner, this method is quite promising in earthquake early warning and rapid source inversion.

Beschreibung: Summary A general-purpose model combining concepts from rational continuum mechanics, fracture and damage mechanics, plasticity, and poromechanics is devised in Eulerian coordinates, involving objective time derivatives. The model complies with mass, momentum, and energy conservation as well as entropy inequality and objectivity. It is devised to cover many diverse phenomena, specifically rupture of existing lithospheric faults, tectonic earthquakes, generation and propagation of seismic waves, birth of new tectonic faults, or volcanic activity, aseismic creep, folding of rocks, aging of rocks, long-distance saturated water transport and flow in poroelastic rocks, melting of rocks and formation of magma chambers, or solidification of magma.

Beschreibung: SUMMARY Information on fault zone structure is essential for our understanding of earthquake mechanics, continental deformation and seismic hazard. We use the scattered seismic wavefield to study the subsurface structure of the North Anatolian Fault Zone (NAFZ) in the region of the 1999 İzmit and Düzce ruptures using data from an 18-month dense deployment of seismometers with a nominal station spacing of 7 km. Using the forward- and back-scattered energy that follows the direct P-wave arrival from teleseismic earthquakes, we apply a scattered wave inversion approach and are able to resolve changes in lithospheric structure on a scale of 10 km or less in an area of about 130 km by 100 km across the NAFZ. We find several crustal interfaces that are laterally incoherent beneath the surface strands of the NAFZ and evidence for contrasting crustal structures either side of the NAFZ, consistent with the presence of juxtaposed crustal blocks and ancient suture zones. Although the two strands of the NAFZ in the study region strike roughly east–west, we detect strong variations in structure both north–south, across boundaries of the major blocks, and east–west, parallel to the strike of the NAFZ. The surface expression of the two strands of the NAFZ is coincident with changes on main interfaces and interface terminations throughout the crust and into the upper mantle in the tomographic sections. We show that a dense passive network of seismometers is able to capture information from the scattered seismic wavefield and, using a tomographic approach, to resolve the fine scale structure of crust and lithospheric mantle even in geologically complex regions. Our results show that major shear zones exist beneath the NAFZ throughout the crust and into the lithospheric mantle, suggesting a strong coupling of strain at these depths.

Beschreibung: Background Immunotherapy yields survival benefit for some advanced stage non-small cell lung cancer (NSCLC) patients. Because highly predictive biomarkers of immunotherapy response are an unmet clinical need, we used pretreatment radiomics and clinical data to train and validate a parsimonious model associated with survival outcomes among NSCLC patients treated with immunotherapy. Methods Three cohorts of NSCLC patients treated with immunotherapy were analyzed: training (n = 180), validation 1 (n = 90), and validation 2 (n = 62). The most informative clinical and radiomic features were subjected to decision tree analysis, which stratified patients into risk groups of low, moderate, high, and very high risk of death after initiation of immunotherapy. All statistical tests were 2-sided. Results The very high-risk group was associated with extremely poor overall survival (OS) in validation cohorts 1 (hazard ratio [HR] = 5.35, 95% confidence interval [CI] = 2.14 to 13.36; 1-year OS = 11.1%, 95% CI = 1.9% to 29.8%; 3-year OS = 0%) and 2 (HR = 13.81, 95% CI = 2.58 to 73.93; 1-year OS = 47.6%, 95% CI = 18.2% to 72.4%; 3-year OS = 0%) when compared with the low-risk group (HR = 1.00) in validation cohorts 1 (1-year OS = 85.0%, 95% CI = 60.4% to 94.9%; 3-year OS = 38.9%, 95% CI = 17.1% to 60.3%) and 2 (1-year OS = 80.2%, 95% CI = 40.3% to 94.8%; 3-year OS = 40.1%, 95% CI = 1.3% to 83.5%). The most informative radiomic feature, gray-level co-occurrence matrix (GLCM) inverse difference, was positively associated with hypoxia-related carbonic anhydrase 9 using gene-expression profiling and immunohistochemistry. Conclusion Utilizing standard-of-care imaging and clinical data, we identified and validated a novel parsimonious model associated with survival outcomes among NSCLC patients treated with immunotherapy. Based on this model, clinicians can identify patients who are unlikely to respond to immunotherapy.

Beschreibung: Abundant silica-undersaturated potassic lavas are found in the centre of the Turkish–Iranian plateau (NW Iran) as flows, pillows and dykes. They display abundant zoned clinopyroxene macrocrysts and xenoliths of igneous cumulates. We determined four types of zoned crystals (Type-I, -II, -III and -IV) on the basis of their composition and zoning patterns. Use of in situ compositional data, together with whole-rock major and trace elements and the isotopic signatures of the host lavas provided evidence for the derivation of the different types of zoned clinopyroxenes from at least two contrasting parental melts. Our findings are consistent with an origin of the ultrapotassic and sodic alkaline melts from the deep-seated compaction pockets inferred from our previous studies of the alkaline magmatism throughout the Turkish–Iranian plateau. The ultrapotassic melt, which accumulated at the top of the compaction pockets, eventually ponded close to the spinel–garnet mantle transition and generated colourless antecrysts (Type-I and Type-II) and clinopyroxenite cumulates. When the compaction pocket impinged on the continental lithosphere, interstitial melts segregated and flowed inside dykes where grass green antecrysts (Type-III) and zoned phenocrysts (Type-IVa) crystallized from a melt having a geochemical signature of sodic alkaline melt. Later, at the crustal level, melt crystallization processes produced Type-IVb zoned phenocrysts. Our results are at odds with the paradigm of potassic magmas in NW Iran being derived strictly from a single mantle source.

Beschreibung: Atlantic bluefin tuna (ABT, Thunnus thynnus; Linneaus, 1758) is an ecologically important apex-predator with high commercial value. They were once common off the coast of the United Kingdom (UK), before disappearing in the 1960s. In regions lacking commercial fisheries for ABT, such as the UK and Ireland, spatial data can be scarce. In these cases, sightings and bycatch databases can offset information shortfalls. Here, we document the reappearance of ABT into territorial waters of the UK from 2014 onwards, and increased occurrence off Ireland. We analyse a novel, multi-source dataset comprising occurrence data (2008–2019; 989 sightings and 114 tonnes of bycatch) compiled from a range of sources (scientific surveys, ecotours and fisheries). We show an increasing trend in effort-corrected ABT occurrence in (i) the pelagic ecosystem survey in the western English Channel and Celtic Sea (PELTIC), (ii) an ecotour operator, and (iii) the Irish albacore fishery in on-shelf and off-shelf waters. Sightings of ABT by the PELTIC correlated with modelled abundance estimates of ABT and the Atlantic multidecadal oscillation. These data demonstrate that sightings of ABT have increased off the UK and Ireland since 2014, following the same increasing trend (2010 onwards) as the eastern ABT population.

Beschreibung: Conventional linear iterative methods for magnetotelluric sounding (MT) suffer from considerable limitations related to difficulties in selecting the initial model and local optima. On the other hand, conventional intelligent nonlinear methods exhibit slow convergence and low accuracy. In this study, we propose an inversion strategy based on the deep learning (DL) deep belief network (DBN) to realise the instantaneous inversion of MT data. A scaled momentum learning rate is introduced to improve the convergence performance of the restricted Boltzmann machine during the DBN pre-training stage, and a novel activation function (DSoft) is introduced to enhance the global optimisation capability during the DBN fine-tuning stage. To address the difficulty in designing the sample data when prior information is lacking, we employ the k-means++ algorithm to cluster the MT field data and use the clustering results as the prior information to guide the construction of the sample dataset. Then, based on the proposed DBN, we ensure end-to-end mapping directly from the apparent resistivity to the resistivity model. We implement two groups of experiments to demonstrate the validity of both improvements on the DBN. We consider six types of geoelectric model from the test set to demonstrate the feasibility and effectiveness of the proposed DBN method for MT 2D inversion, which we further compare with the well-known least-square regularisation method for several extended geoelectric models and field data. The qualitative and quantitative analyses show that the DL inversion method is promising as it can accurately delineate the subsurface structures and perform rapid inversion.

Beschreibung: With the development of complex and unconventional reservoirs, oil and gas exploration becomes increasingly difficult. Highly deviated wells/horizontal wells are widely used. The electromagnetic propagation logging while drilling (LWD) is more effective in complex geological environment detection owing to geological orientation and real-time formation evaluation. However, its operating frequency is generally at the MHz level. Traditional acquisition techniques require an analogue to digital converter with high sampling rates, which will introduce complex circuit structures and increase sampling costs. The undersampling technology has overcome these disadvantages. The difficulties in the undersampling technology include the selection of an undersampling frequency and the acquisition of a signal correction coefficient. The range of undersampling frequencies and a correction coefficient has been developed to process the electromagnetic propagation LWD measurements in this paper. The range of undersampling frequency ensures the validity of the sampled data. The correction coefficient ensures that different frequency signals use the same undersampling frequency to obtain the same frequency recovery signal. The correctness of these parameters is verified by simulation and field data examples. The range of undersampling frequency and a correction coefficient has been applied, improving the data stability and providing reliable technical support for the exploration and development of unconventional oil and gas.

Beschreibung: Determining the crack initiation stress (Ci) for unconventional shale rocks is of critical importance in describing the entire failure process of unconventional shale reservoirs. We propose a new method to identify Ci values based on triaxial failure tests on four organic shale samples, attempting to improve the shortcomings of other methods. The new method is based on the relationship between crack development and strain energy evolution (SEE). Additionally, the proposed SEE method is compared with three widely used methods, including crack volumetric strain (CVS), moving point regression (MPR) and the lateral strain response (LSR), intending to examine the performance of different methods. The contrastive results indicate that the LSR method cannot determine Ci when the rock ruptures without volumetric dilatancy, which frequently occurs in the compression process of organic shales. Ci values obtained using the SEE method are consistent with those from the CVS and MPR methods. However, the proposed SEE method with a solid physical basis is more objective and stable than the CVS and MPR methods. The proposed method, from one aspect, compensates for the shortcomings of other methods when facing different failure modes in organic shales. From the other aspect, it provides a way to precisely determine Ci values for applications in wellbore stability evaluation and hydraulic fracturing design.

Beschreibung: Background Circulating levels of cancer antigen (CA) 15–3, a tumor marker and regulator of cellular metabolism, were reduced by metformin in a nonrandomized neoadjuvant study. We examined the effects of metformin (vs placebo) on CA 15–3 in participants of MA.32, a phase III randomized trial in early-stage breast cancer. Methods A total of 3649 patients with T1-3, N0-3, M0 breast cancer were randomly assigned; pretreatment and 6-month on-treatment fasting plasma were centrally assayed for CA 15–3. Genomic DNA was analyzed for the rs11212617 single nucleotide polymorphism. Absolute and relative change of CA 15–3 (metformin vs placebo) were compared using Wilcoxon rank and t tests. Regression models adjusted for baseline differences and assessed key interactions. All statistical tests were 2-sided. Results Mean (SD) age was 52.4 (10.0) years. The majority of patients had T2/3, node-positive, hormone receptor–positive, HER2-negative breast cancer treated with (neo)adjuvant chemotherapy and hormone therapy. Mean (SD) baseline CA 15–3 was 17.7 (7.6) and 18.0 (8.1 U/mL). At 6 months, CA 15–3 was statistically significantly reduced in metformin vs placebo arms (absolute geometric mean reduction in CA 15–3 = 7.7% vs 2.0%, P  .11). Conclusions Our observation that metformin reduces CA 15–3 by approximately 6% was corroborated in a large placebo-controlled randomized trial. The clinical implications of this reduction in CA 15–3 will be explored in upcoming efficacy analyses of breast cancer outcomes in MA.32.

Beschreibung: Background Adipocyte-derived adiponectin may play a role in the host inflammatory response to cancer. We examined the association of plasma adiponectin with the density of tumor-infiltrating lymphocytes (TILs) in colon cancers and with vitamin D, clinicopathological features, and patient survival. Methods Plasma adiponectin and 25-hydroxyvitamin D [25(OH)D] were analyzed by radioimmunoassay in 600 patients with stage III colon cancer who received FOLFOX-based adjuvant chemotherapy (NCCTG N0147 [Alliance]). TIL densities were determined in histopathological sections. Associations with disease-free survival (DFS), time to recurrence, and overall survival were evaluated by multivariable Cox regression adjusting for potential confounders (ie, body mass index, race, TILs, and N stage). All statistical tests were 2-sided. Results We found a statistically significant reduction in adiponectin, but not 25(OH)D, levels in tumors with high vs low TIL densities (median = 6845 vs 8984 ng/mL; P = .04). A statistically significant reduction in adiponectin was also observed in obese (body mass index 〉30 kg/m2) vs nonobese patients (median = 6608 vs 12 351 ng/mL; P 

Beschreibung: Background Despite a substantially worse risk factor profile, Hispanics in the United States experience lower incidence of many diseases and longer survival than non-Hispanic Whites (NHWs), an epidemiological phenomenon known as the Hispanic Health Paradox (HHP). This systematic review evaluated the published longitudinal literature to address whether this pattern extends to lung cancer survival. Methods Searches of Medline, PubMed, Embase, Web of Science, and the Cochrane Library were conducted for publications dated from January 1, 2000, to July 18, 2018. Records were restricted to articles written in English, employing a longitudinal design, and reporting a direct survival comparison (overall survival [OS], cancer-specific survival [CSS]) between NHW and Hispanic lung cancer patients. Results A final sample of 29 full-text articles were included, with 28 fully adjusted models of OS and 21 of CSS included. Overall, 26 (92.9%) OS models and 20 (95.2%) CSS models documented either no difference (OS = 16, CSS = 11) or a Hispanic survival advantage (OS = 10, CSS = 9). Both larger studies and those including foreign-born Hispanics were more likely to show a Hispanic survival advantage, and 2 studies of exclusively no-smokers showed a survival disadvantage. A number of reporting gaps were identified including Hispanic background and sociodemographic characteristics. Conclusions Hispanics exhibit similar or better survival in the context of lung cancer relative to NHWs despite a considerably worse risk factor profile. These findings support the HHP in the context of lung cancer. Further research is needed to understand the potential mechanisms of the HHP as it relates to lung cancer.

Beschreibung: Next-generation sequencing (NGS)-library preparation for whole-genome sequencing (WGS) starts with DNA fragmentation, and sonication is a physical approach used most often due to its simplicity and reproducibility. However, the commercially available Covaris instrument has a high price for both the device and consumables. Here, we describe our in-house method of DNA shearing by sonication with small (100–600 µm) glass beads and an ultrasonic bath. The fragmentation conditions were optimized for the bacterial WGS with ∼550-bp fragment size (the ultrasonic bath water temperature 5–10°C, glass beads 0.06 g, the fragmentation time 50 s) and for human DNA with ∼250 bp (fragmentation with the same parameters for 4 min). Fragmentation results were compared with the Covaris instrument for preparing several bacterial NGS libraries for Illumina NGS platforms by several characteristics. We obtained close mean fragment lengths (523–623 versus 480–646), similar mono- and dinucleotide specificity of shearing, and comparable indicators of read alignment and de novo assembly for both methods. Thus, the described method is a new fast, and effective DNA fragmentation approach that can be used in different WGS applications.

Beschreibung: The euphausiid genus Stylocheiron includes species with biogeographical distributions spanning multiple ocean basins. Despite their circumglobal distributions, the species show low levels of genetic diversity and little or no evidence of population structure based on the mitochondrial cytochrome oxidase I (COI) barcode region, with the exception of a possible cryptic species within Stylocheiron affine. Stylocheiron elongatum showed 

Beschreibung: SUMMARY The seismograms for the multiscale crustal model due to dislocations are synthesized by a revised direct stiffness matrix method. By extracting the exponential growth terms related to wavenumber and layer thickness, the fast and accurate wavefield modelling can be achieved for the multiscale system with superficial fine layers (the layer thickness and velocity vary from metre level in the near-surface to kilometre level in deep crustal zones). This method allows relatively high-frequency cases of engineering interest (about 10 Hz) to be tackled without extra computations, linking the geophysics to the geotechnical earthquake engineering. The simulations considering superficial fine layers (5–50  m) show that the horizontal peak ground velocities can be amplified twice with superficial velocity decreasing from 0.4 to 0.15 km s–1. A case study using a realistic fine model in Tokyo metropolis elucidates that the displacements are localized within the epicentre distance about 5 km, predicting the displacement responses by factors up to 6.7, 1.1 and 6.7 for radial, tangential and vertical directions in comparison to the simplified model without superficial fine structures.

Beschreibung: Mutation of Asp97Tyr in the C-terminal region of ferredoxin (PfFd) in the apicoplast of malaria parasites was recently reported to be strongly related to the parasite’s resistance to the frontline antimalarial drug, artemisinin. We previously showed that the aromatic amino acid in the C-terminal region of PfFd is important for the interaction with its electron transfer partner, Fd-NADP+ reductase (PfFNR). Here, the importance of the aromatic–aromatic interaction between PfFd and PfFNR was shown using the kinetic analysis of the electron transfer reaction of site-directed mutants of PfFNR with PfFd. Mutation of Asp97Tyr of PfFd was further shown to increase the affinity with PfFNR by the measurements of the dissociation constant (Kd) using tryptophan fluorescence titration and the Michaelis constant (Km) in the kinetic analysis with PfFNRs. Diaphorase activity of PfFNR was inhibited by D97Y PfFd at lower concentration as compared to wild-type PfFd. Ascorbate radical scavenging activity of PfFd and electron transfer activity to a heterogeneous Fd-dependent enzyme was lower with D97Y PfFd than that of wild-type PfFd. These results showed that D97Y mutant of PfFd binds to PfFNR tighter than wild-type PfFd, and thus may suppress the function of PfFNR which could be associated with the action of artemisinin.

Beschreibung: Phase equilibria and trace-element modeling using two previously reported basaltic bulk-rock compositions (samples D11 and 104-16), were carried out in this study, in order to better understand mechanism of low-pressure (LP) partial melting of mafic rocks and associated melt compositions. The T–MH2O pseudosections for both samples at three pressures (i.e. 0.5, 1.0 and 2.0 kbar) display that the H2O-stability field gradually increased with decreasing pressure within the T–MH2O range of 600–1100 °C and 0–12 mol.%. The H2O contents of 10, 5.0, and 0.5 mol.% were selected on the basis of the T–MH2O pseudosections to calculate P–T pseudosections over a P–T window of 0.1–3 kbar and 600–1100 °C, so that the reactions of both the H2O-fluxed and -absent meltings at LP conditions can be investigated. The solidus displays a negative or near-vertical P–T slope, and occurs between 710 and 900 °C at pressure between 0.1 and 3.0 kbar. LP melting of metabasites is attributed to the reactions of the hydrous mineral (hornblende and/or biotite) melting and anhydrous mineral (plagioclase, orthopyroxene, and augite) melting. The hydrous mineral melting is gradually replaced by anhydrous mineral melting as pressure decreasing, as the stability of hornblende decreases with falling pressure. With increasing temperature at a given pressure, the modeled melt compositions are expressed as progressions of the granite-granodiorite-gabbroic diorite fields for sample D11and granite-quartz monzonite-monzonite-gabbroic diorite fields for sample 104-16 on the total alkali–silica diagram. The modeled melts produced through the H2O-fluxed melting display higher Al2O3, CaO, MgO, and lower SiO2 and K2O than those formed by H2O-absent melting at the same P–T conditions. Furthermore, the modeled melts formed by H2O-absent melting, become richer in Al2O3, CaO, MgO, FeO, Na2O, but poorer in SiO2 and K2O as increasing water content. The results of trace-element modeling suggests that the nearly flat REE patterns of modeled bulk-rock composition are inherited by all the modeled melts, and the negative Eu anomalies and Sr depletion of the modeled melts gradually decrease as melting degree increases. Combined with the geochemical characteristics of natural oceanic plagiogranites, which have low K2O contents and flat or slightly LREE-depleted REE patterns, our results imply that a bulk-rock composition with low K2O (

Beschreibung: A substantial body of work has been carried out describing the structural features of the complex between single-domain antibodies (VHHs) and antigens, and the preeminence for epitopes located at concave surfaces of the antigen. However, the thermodynamic basis of binding is far less clear. Here, we have analyzed the energetic profiles of five VHHs binding to the catalytic cleft as well as a non-cleft epitope of hen egg lysozyme. Various binding energetic profiles with distinctive enthalpic/entropic contributions and structural distribution of critical residues were found in the five antibodies analyzed. Collectively, we suggest that from an energetic point of view the binding mechanism is influenced by the shape of the epitope. This information may be beneficial for the design of tailored epitopes for VHHs and their practical use.

Beschreibung: SUMMARY Detecting P-wave onsets for online processing is an important component for real-time seismology. As earthquake early warning systems around the world come into operation, the importance of reliable P-wave detection has increased, since the accuracy of the earthquake information depends primarily on the quality of the detection. In addition to the accuracy of arrival time determination, the robustness in the presence of noise and the speed of detection are important factors in the methods used for the earthquake early warning. In this paper, we tried to improve the P-wave detection method designed for real-time processing of continuous waveforms. We used the new Tpd method, and proposed a refinement algorithm to determine the P-wave arrival time. Applying the refinement process substantially decreases the errors of the P-wave arrival time. Using 606 strong motion records of the 2011 Tohoku earthquake sequence to test the refinement methods, the median of the error was decreased from 0.15 to 0.04 s. Only three P-wave arrivals were missed by the best threshold. Our results show that the Tpd method provides better accuracy for estimating the P-wave arrival time compared to the STA/LTA method. The Tpd method also shows better performance in detecting the P-wave arrivals of the target earthquakes in the presence of noise and coda of previous earthquakes. The Tpd method can be computed quickly, so it would be suitable for the implementation in earthquake early warning systems.

Beschreibung: Major changes in North Atlantic zooplankton communities in recent decades have been linked to climate change but the roles of environmental drivers are often complex. High temporal resolution data is required to disentangle the natural seasonal drivers from additional sources of variability in highly heterogeneous marine systems. Here, physical and plankton abundance data spanning 2003–2017 from a weekly long-term monitoring site on the west coast of Scotland were used to investigate the cause of an increasing decline to approximately -80± 5% in annual average total zooplankton abundance from 2011 to 2017. Generalized additive mixed models (GAMMs), with an autoregressive correlation structure, were used to examine seasonal and inter-annual trends in zooplankton abundance and their relationship with environmental variables. Substantial declines were detected across all dominant taxa, with ∼ 30–70% of the declines in abundance explained by a concurrent negative trend in salinity, alongside the seasonal cycle, with the additional significance of food availability found for some taxa. Temperature was found to drive seasonal variation but not the long-term trends in the zooplankton community. The reduction in salinity had the largest effect on several important taxa. Salinity changes could partly be explained by locally higher freshwater run-off driven by precipitation as well as potential links to changes in offshore water masses. The results highlight that changes in salinity, caused by either freshwater input (expected from climate predictions) or fresher offshore water masses, may adversely impact coastal zooplankton communities and the predators that depend on them.

Beschreibung: Summary Seismic coda waves are commonly used in estimation of subsurface Q values and monitoring subsurface changes. Coda waves mainly consist of multiply scattered body and surface waves. These two types of waves interact with each other in the multiple scattering process, which thus leads to a spatiotemporal evolution of the body- and surface-wave energies. One cannot characterize the evolution because one has not fully understood the multiple scattering of the two types of waves. Thus one commonly assumes only one type of waves exists or ignores their interaction while studying the coda waves. However, neglecting the interaction leads to an incorrect energy evolution of the two types of waves and consequently biases the Q estimation or interpretation of coda-wave changes for monitoring. To better understand the interaction between these waves during multiple scattering and to model the energy evolution correctly, we propose a Monte Carlo algorithm to model the multiple scattering process. We describe the physics of the scattering for the two types of waves and derive scattering properties like cross sections for perturbations in elastic properties (e.g. density, shear modulus and Lamé parameters). Our algorithm incorporates this knowledge and thus physically models the body- and surface-wave energy evolution in space and time. The energy partitioning ratios between surface and body waves provided by our algorithm match the theoretical prediction based on equipartition theory. In the equipartition state, our simulation results also match Lambert’s cosine law for body waves on the free surface. We discuss how the Rayleigh-to-body-wave scattering affects the energy partitioning ratios. Our algorithm provides a new tool to study multiple scattering and coda waves in elastic media with a free surface.

Beschreibung: SUMMARY Seismic and magnetic observations have suggested the presence of a stably stratified layer atop Earth’s core. Such a layer could affect the morphology of the geomagnetic field and the evolution of the core, but the precise impact of this layer depends largely on its internal dynamics. Among other physical phenomena, stratified layers host internal gravity waves (IGW), which can be excited by adjacent convective motions. Internal waves are known to play an important role on the large-scale dynamics of the Earth’s climate and on the long-term evolution of stars. Yet, they have received relatively little attention in the Earth’s outer core so far and deserve detailed investigations in this context. Here, we make a first step in that direction by running numerical simulations of IGW in a non-rotating spherical shell in which a stratified layer lies on top of a convective region. We use a nonlinear equation of state to produce self-consistently such a two-layer system. Both propagating waves and global modes coexist in the stratified layer. We characterize the spectral properties of these waves and find that energy is distributed across a wide range of frequencies and length scales, that depends on the Prandtl number. For the control parameters considered and in the absence of rotational and magnetic effects, the mean kinetic energy in the layer is about 0.1 per cent that of the convective region. IGW produce perturbations in the gravity field that may fall within the sensitivity limit of present-day instruments and could potentially be detected in available data. We finally provide a road map for future, more geophysically realistic, studies towards a more thorough understanding of the dynamics and impact of internal waves in a stratified layer atop Earth’s core.

Beschreibung: SUMMARY The offshore part of the North Anatolian Fault (NAF) beneath the Marmara Sea is a well-known seismic gap for future M 〉 7 earthquakes in the sense that more than 250 yr have passed since the last major earthquake in the Central Marmara region. Although many studies discussed the seismic potential for the future large earthquake in this region on the basis of historical record, geodetic and geological observations, it is difficult to evaluate the actual situation on the seismic activity and structure along the NAF beneath the Marmara Sea due to the lack of ocean bottom seismic observations. Using ocean bottom seismometer observations, an assessment of the location of possible asperities that could host an expected large earthquake is undertaken based on heterogeneities in the microseismicity distribution and seismic velocity structure. Specifically, seismic tomography and precise hypocentre estimations are conducted using offshore seismic data whose recording period is 11 months. About five times more microearthquakes are detected with respect to events recorded in a land-based catalogue. A comparison with previously published results from offshore observation data suggests that the seismicity pattern had not changed from 2014 September to 2017 May. The location accuracy of microearthquakes is greatly improved from only the land-based earthquake catalogue, particularly for depth direction. There are several aseismic and inactive zones of microearthquake, and the largest one is detected using land-based seismic observation, whereas other zones are newly detected via offshore observations. The obtained velocity model shows a strong lateral contrast, with two changing points. The western changing point corresponds to a segmentation boundary, where the dip angle of the NAF segments changed. High-velocity zones from tomographic images are characterized by low seismicity eastward of the segment boundary. To the east of 28.50°E, the high-velocity zone becomes thicker in the depth direction and is characterized by low seismicity. Although the low seismic activity alone could be interpreted as both strong coupling and fully creeping, the high-velocity features at the same can be concluded that these zones are consist of brittle material and strong coupling. From comparison with other geodetic and seismic studies, we interpret these zones as locked zones that had been ruptured by the past large earthquakes and could be ruptured by future ones. These zones might accumulate strain since the main shock rupture associated with the 1766 May Ms 7.3 earthquake, the latest major earthquake in this region.

Beschreibung: SUMMARY The stress drop is an important dynamic source parameter for understanding the physics of source processes. The estimation of stress drops for moderate and small earthquakes is based on measurements of the corner frequency ${f_c}$, the seismic moment ${M_0}$ and a specific theoretical model of rupture behaviour. To date, several theoretical rupture models have been used. However, different models cause considerable differences in the estimated stress drop, even in an idealized scenario of circular earthquake rupture. Moreover, most of these models are either kinematic or quasi-dynamic models. Compared with previous models, we use the boundary integral equation method to simulate spontaneous dynamic rupture in a homogeneous elastic full space and then investigate the relations between the corner frequency, seismic moment and source dynamic parameters. Spontaneous ruptures include two states: runaway ruptures, in which the rupture does not stop without a barrier, and self-arresting ruptures, in which the rupture can stop itself after nucleation. The scaling relationships between ${f_c}$, ${M_0}$ and the dynamic parameters for runaway ruptures are different from those for self-arresting ruptures. There are obvious boundaries in those scaling relations that distinguish runaway ruptures from self-arresting ruptures. Because the stress drop varies during the rupture and the rupture shape is not circular, Eshelby's analytical solution may be inaccurate for spontaneous dynamic ruptures. For runaway ruptures, the relations between the corner frequency and dynamic parameters coincide with those in the previous kinematic or quasi-dynamic models. For self-arresting ruptures, the scaling relationships are opposite to those for runaway ruptures. Moreover, the relation between ${f_c}$ and ${M_0}$ for a spontaneous dynamic rupture depends on three factors: the dynamic rupture state, the background stress and the nucleation zone size. The scaling between ${f_c}$ and ${M_0}$ is ${f_c} propto {M_0^{ - n}}$, where n is larger than 0. Earthquakes with the same dimensionless dynamic parameters but different nucleation zone sizes are self-similar and follow a ${f_c} propto {M_0^{ - 1/3}}$ scaling law. However, if the nucleation zone size does not change, the relation between ${f_c}$ and ${M_0}$ shows a clear departure from self-similarity due to the rupture state or background stress.

Beschreibung: Natural floating objects (FOBs) have always been a major component of the habitat of pelagic species. Since the 1990s, the number of FOBs in the open ocean has increased greatly as a result of the introduction of fish aggregating devices (FADs) by the industrial tropical tuna purse seine vessels. These changes, and their potential impacts on the species that associate with FOBs, remain poorly understood. Using fisheries observer data, data from satellite-linked tracking buoys attached to FOBs and Lagrangian simulations, this study quantifies the temporal changes in the density and spatial distribution of FOBs due to the use of FADs in the Indian Ocean (IO) between 2006 and 2018. From 2012 to 2018, the entire western IO is impacted, with FADs representing more than 85% of the overall FOBs, natural FOBs less than 10%, and objects originating from pollution 5%. Results also suggest that both FADs and natural FOBs densities are lower in the eastern IO, but this initial investigation highlights the need for further studies. Our study confirms that FADs have greatly modified the density and spatial distribution of FOBs, which highlights the need to investigate potential consequences on the ecology of associated species.

Beschreibung: Summary Long term deformations strongly depend on the Earth model and its rheological parameters, and in particular its viscosity. We give the general theory and the numerical scheme to compute them for any spherically non rotating isotropic Earth model with linear rheology, either elastic or viscoelastic. Although the Laplace transform is classically used to compute viscoelastic deformation, we choose here instead, to implement the integration with the Fourier transform in order to take advantage of the Fast Fourier Transform algorithm and avoid some of the Laplace transform mathematical difficulties. We describe the methodology to calculate deformations induced by several geophysical signals regardless of whether they are periodic or not, especially by choosing an adapted time sampling for the Fourier transform. As examples, we investigate the sensitivity of the displacements due to long period solid Earth tides, Glacial Isostatic Adjustment (GIA), and present-day ice melting, to anelastic parameters of the mantle. We find that the effects of anelasticity are important for long period deformation and relatively low values of viscosities for both Maxwell and Burgers models. We show that slight modifications in the rheological models could significantly change the amplitude of deformation but also affect the spatial and temporal pattern of the signal to a lesser extent. Especially, we highlight the importance of the mantle anelasticity in the low degrees deformation due to present-day ice melting and encourage its inclusion in future models.

Beschreibung: The frequency-dependent amplitude-versus-offset (FAVO) method has become a practical method for fluid detection in sand reservoirs. At present, most FAVO inversions are based on the assumption that reservoirs are isotropy, but the application effect is not satisfactory for fractured reservoirs. Hence, we analyse the frequency variation characteristics of anisotropy parameters in tight sandstone reservoirs based on a new petrophysical model, and propose a stepwise anisotropic FAVO inversion method to extract frequency-dependent attributes from prestack seismic field data. First, we combine the improved Brie's law with the fine-fracture model to analyse frequency-dependent characteristics of velocities and Thomsen anisotropy parameters at different gas saturations and fracture densities. Then, we derive an anisotropic FAVO inversion algorithm based on Rüger's approximation formula and propose a stepwise anisotropic FAVO inversion method to obtain the dispersions of anisotropy parameters. Finally, we propose a method that combines the inversion spectral decomposition with the stepwise anisotropy FAVO inversion and apply it to tight sand reservoirs in the Xinchang area. We use P-wave velocity dispersion and anisotropy parameter ε dispersion to optimise favourable areas. Numerical analysis results show that velocity dispersion of the P-wave is sensitive to fracture density, which can be used for fracture prediction in fractured reservoirs. In contrast, anisotropic parameter dispersion is sensitive to gas saturation and can be used for fluid detection. The seismic data inversion results show that velocity dispersion of the P-wave and anisotropic parameter dispersion are sensitive to fractured reservoirs in the second member of Xujiahe Group, which is consistent with logging interpretation results.

Beschreibung: SUMMARY Induced polarization (IP) is an acknowledged method in ore exploration and can be applied to evaluate the metal content in dumps containing the residues of ore processing facilities. Existing models explain the relationships between ore content and grain size of the ore particles with IP parameters. However, the models assume full water saturation of the ore containing samples, which is often not the case in field conditions at dump sites. Hence, our study investigates the effect of desaturation on the resulting IP signal. We used six different sand–pyrite mixtures with varying amount and grain sizes of the pyrite particles. Evaporative drying desaturated the samples. Complex conductivity spectra were recorded in the frequency range between 0.02 and 1000 Hz at certain saturation levels. The resulting spectra indicate an decrease of the conductivity amplitude with progressing desaturation. This effect agrees with the second empirical Archie equation. The saturation exponent of the conductivity amplitude shows values slightly larger than one. The measured spectra were processed by a Debye decomposition. We observe a nearly constant total chargeability during desaturation. This finding is in agreement with existing models that relate the total chargeability to the metal content in the sample. However, the mean relaxation time decreases remarkably during the drying process, whereas the normalized relaxation time, which considers the ratio between the mean relaxation time and the resistivity of the embedding material, does not indicate any dependence on water saturation. This behaviour contradicts existing models that predict a decreasing relaxation time with increasing water salinity, which results from evaporative drying. In order to explain the observed effects, we propose a conceptional model that compares a mixture of pyrite particles in an embedding material (sand, water and air) with an electrical RC circuit. The pyrite grains behave as small condensers that are charged and discharged via the conductive background material. According to this simple physical model, the relaxation time is proportional to the resistivity of the embedding material. A resistivity increase while desaturation causes an increase of relaxation time as observed in our experiments. This conceptional model is in good agreement with other experiments that change the resistivity in the background material by varying water salinity or clay content. The capacitive behaviour of the dispersed particles is characterized by the normalized relaxation time that depends on the grain size and the volume content of the pyrite particles.

Beschreibung: SUMMARY A novel approach to computing the Earth's normal modes is presented. With the Langer approximation incorporated into the framework of the theory of the generalized reflection/transmission coefficients, our method, when applied to calculate the toroidal modes, produces results that agree extremely well with the exact results from Mineos and successfully overcomes the limitations of the WKBJ analysis. Given any 1-D earth model, regardless of the number of discontinuities, our method can perform the calculations reliably with satisfactory accuracy at high frequencies. The success achieved with the toroidal modes encourages us to tackle in a future study the asymptotic computation of the spheroidal modes, especially those high-frequency trapped modes for which the accuracy of Mineos is demonstrably inadequate.

Beschreibung: SUMMARY Geomagnetic data assimilation merges past and present-day observations of the Earth’s magnetic field with numerical geodynamo models and the results are used to initialize forecasts. We present a new ‘proxy model’ that can be used to test, or rapidly prototype, numerical techniques for geomagnetic data assimilation. The basic idea for constructing a proxy is to capture the conceptual difficulties one encounters when assimilating observations into high-resolution, 3-D geodynamo simulations, but at a much lower computational cost. The framework of using proxy models as ‘gate-keepers’ for numerical methods that could/should be considered for more extensive testing on operational models has proven useful in numerical weather prediction, where advances in data assimilation and, hence, improved forecast skill, are at least in part enabled by the common use of a wide range of proxy models. We also present a large set of systematic data assimilation experiments with the proxy to reveal the importance of localization and inflation in geomagnetic data assimilation.

Beschreibung: SUMMARY Simplified solutions of the Bloch equation can lead to inaccurate estimates of hydrogeological parameters from surface nuclear magnetic resonance measurements. Even for single pulse measurements, using simplified forward models is common practice because of the computational intensity of obtaining the full-Bloch solution. These challenges are exacerbated for multipulse sequences. We show parallelizing the full-Bloch solver on a Graphics Processing Unit reduces the solve time by three orders of magnitude. Further optimizations by numerical, analytical and hybrid solutions yield an additional 3× speed up. We simulate the full-Bloch physics for free-induction decay, spin-echo and pseudo-saturation recovery excitation schemes for an unprecedented range of physical scenarios. We explore the time-dependence and relaxation time sensitivity in these solution spaces. Characterizing the solution spaces with polynomials of the relaxation times, the solutions can be rapidly reproduced; a technique known as fast-mapping. By fitting these higher dimensional solution ensembles with polynomials, the original fast-mapping technique is extended to include T1 at arbitrary times. Accuracy of the 7th order polynomial is such that a minimum 96 per cent of the models are within a ±3 per cent relative error. This permits the rapid reproduction of full-Bloch solutions with a matrix multiplication and opens up surface NMR to time-series based inversion of single and multipulse data.

Beschreibung: SUMMARY Measurements of various physical properties of oceanic sediment and crustal structures provide insight into a number of geological and geophysical processes. In particular, knowledge of the shear wave velocity (VS) structure of marine sediments and oceanic crust has wide ranging implications from geotechnical engineering projects to seismic mantle tomography studies. In this study, we propose a novel approach to nonlinearly invert compliance signals recorded by colocated ocean-bottom seismometers and high-sample-rate pressure gauges for shallow oceanic shear wave velocity structure. The inversion method is based on a type of machine learning neural network known as a mixture density neural network (MDN). We demonstrate the effectiveness of the MDN method on synthetic models with a fixed deployment depth of 2015 m and show that among 30 000 test models, the inverted shear wave velocity profiles achieve an average error of 0.025 km s−1. We then apply the method to observed data recorded by a broad-band ocean-bottom station in the Lau basin, for which a VS profile was estimated using Monte Carlo sampling methods. Using the mixture density network approach, we validate the method by showing that our VS profile is in excellent agreement with the previous result. Finally, we argue that the mixture density network approach to compliance inversion is advantageous over other compliance inversion methods because it is faster and allows for standardized measurements.

Beschreibung: SUMMARY It is generally agreed that the Last Interglacial (LIG; ∼130–115 ka) was a time when global average temperatures and global mean sea level were higher than they are today. However, the exact timing, magnitude and spatial pattern of ice melt is much debated. One difficulty in extracting past global mean sea level from local observations is that their elevations need to be corrected for glacial isostatic adjustment (GIA), which requires knowledge of Earth’s internal viscoelastic structure. While this structure is generally assumed to be radially symmetric, evidence from seismology, geodynamics and mineral physics indicates that large lateral variations in viscosity exist within the mantle. In this study, we construct a new model of Earth’s internal structure by converting shear wave speed into viscosity using parametrizations from mineral physics experiments and geodynamic constraints on Earth’s thermal structure. We use this 3-D Earth structure, which includes both variations in lithospheric thickness and lateral variations in viscosity, to calculate the first 3-D GIA prediction for LIG sea level. We find that the difference between predictions with and without lateral Earth structure can be metres to 10s of metres in the near field of former ice sheets, and up to a few metres in their far field. We demonstrate how forebulge dynamics and continental levering are affected by laterally varying Earth structure, with a particular focus on those sites with prominent LIG sea level records. Results from four 3-D GIA calculations show that accounting for lateral structure can act to increase local sea level by up to ∼1.5 m at the Seychelles and minimally decrease it in Western Australia. We acknowledge that this result is only based on a few simulations, but if robust, this shift brings estimates of global mean sea level from these two sites into closer agreement with each other. We further demonstrate that simulations with a suitable radial viscosity profile can be used to locally approximate the 3-D GIA result, but that these radial profiles cannot be found by simply averaging viscosity below the sea level indicator site.