Change of deep subduction seismicity after a large megathrust earthquake.

Subduction zones are home to the world's largest and deepest earthquakes. Recently, large-scale interactions between shallow (0-60 km) and intermediate (80-150 km) seismicity have been evidenced during the interseismic period but also before and after megathrust earthquakes along with large-scale changes in surface motion. Large-scale deformation transients following major earthquakes have also been observed possibly due to a post-seismic change in slab pull or to a bending/unbending of the plates, which suggests the existence of interactions between the deep and shallow parts of the slab. In this study, we analyze the spatio-temporal variations of the declustered seismicity in Japan from 2000 to 2011/3/11 and from 2011/3/11 to 2013/3/11. We observe that the background rate of the intermediate to deep (150-450 km) seismicity underwent a deceleration of 55% south of the rupture zone and an acceleration of 30% north of it after the Tohoku-oki earthquake, consistent with the GPS surface displacements. This shows how a megathrust earthquake can affect the stress state of the slab over a 2500 km lateral range and a large depth range, demonstrating that earthquakes interact at a much greater scale than the surrounding rupture zone usually considered.

Basaltic reservoirs in the Earth's mantle transition zone.

The formation and preservation of compositional heterogeneities inside the Earth affect mantle convection patterns globally and control the long-term evolution of geochemical reservoirs. However, the distribution, nature, and size of reservoirs in the Earth's mantle are poorly constrained. Here, we invert measurements of travel times and amplitudes of seismic waves interacting with mineralogical phase transitions at 400-700-km depth to obtain global probabilistic maps of temperature and bulk composition. We find large basalt-rich pools (up to 60% basalt fraction) surrounding the Pacific Ocean, which we relate to the segregation of oceanic crust from slabs that have been subducted since the Mesozoic. Segregation of oceanic crust from initially cold and stiff slabs may be facilitated by the presence of a weak hydrated layer in the slab or by weakening upon mineralogical transition due to grain-size reduction.

Seismic evidence for partial melt below tectonic plates.

The seismic low-velocity zone (LVZ) of the upper mantle is generally associated with a low-viscosity asthenosphere that has a key role in decoupling tectonic plates from the mantle1. However, the origin of the LVZ remains unclear. Some studies attribute its low seismic velocities to a small amount of partial melt of minerals in the mantle2,3, whereas others attribute them to solid-state mechanisms near the solidus4-6 or the effect of its volatile contents6. Observations of shear attenuation provide additional constraints on the origin of the LVZ7. On the basis of the interpretation of global three-dimensional shear attenuation and velocity models, here we report partial melt occurring within the LVZ. We observe that partial melting down to 150-200 kilometres beneath mid-ocean ridges, major hotspots and back-arc regions feeds the asthenosphere. A small part of this melt (less than 0.30 per cent) remains trapped within the oceanic LVZ. Melt is mostly absent under continental regions. The amount of melt increases with plate velocity, increasing substantially for plate velocities of between 3 centimetres per year and 5 centimetres per year. This finding is consistent with previous observations of mantle crystal alignment underneath tectonic plates8. Our observations suggest that by reducing viscosity9 melt facilitates plate motion and large-scale crystal alignment in the asthenosphere.

Author Correction: Evidence for a serpentinized plate interface favouring continental subduction.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Evidence for a serpentinized plate interface favouring continental subduction.

The dynamics of continental subduction is largely controlled by the rheological properties of rocks involved along the subduction channel. Serpentinites have low viscosity at geological strain rates. However, compelling geophysical evidence of a serpentinite channel during continental subduction is still lacking. Here we show that anomalously low shear-wave seismic velocities are found beneath the Western Alps, along the plate interface between the European slab and the overlying Adriatic mantle. We propose that these seismic velocities indicate the stacked remnants of a weak fossilised serpentinite channel, which includes both slivers of abyssal serpentinite formed at the ocean floor and mantle-wedge serpentinite formed by fluid release from the subducting slab. Our results suggest that this serpentinized plate interface may have favoured the subduction of continental crust into the upper mantle and the formation/exhumation of ultra-high pressure metamorphic rocks, providing new constraints to develop the conceptual and quantitative understanding of continental-subduction dynamics.

Semi-automated crater depth measurements.

Impact cratering is a major process driving planetary landscape evolution. Statistics of craters spatial density is extensively used to date planetary surfaces. Their degradation state and morphometry are also key parameters to understand surface processes. To exploit the increasing coverage of digital terrain models (DEM) on Mars at high spatial resolution, we propose a semi-automated pipeline for crater depth measurement based on coupled optical images and DEM. From a craters map shapefile coupled with a co-registered DEM, we propose to measure crater depth as the difference between the 60th percentile of elevation values on the edge of the crater and the 3rd percentile value of the elevations within the crater. We present here this method and its calibration. •Aside to this paper, we provide a simple python code of this pipeline.•This method can rapidly produce crater depth dataset big enough to be interpreted statistically.•We provide solid tests on the precision of measured crater depth. Especially, we show that minimal elevation value within a crater, sometime used as crater floor elevation, is a far less precise approximation than a low percentile of elevation.

Flexible Coupling in Joint Inversions: A Bayesian Structure Decoupling Algorithm.

When different geophysical observables are sensitive to the same volume, it is possible to invert them simultaneously to jointly constrain different physical properties. The question addressed in this study is to determine which structures (e.g., interfaces) are common to different properties and which ones are separated. We present an algorithm for resolving the level of spatial coupling between physical properties and to enable both common and separate structures in the same model. The new approach, called structure decoupling (SD) algorithm, is based on a Bayesian trans-dimensional adaptive parameterization, where models can display the full spectra of spatial coupling between physical properties, from fully coupled models, that is, where identical model geometries are imposed across all inverted properties, to completely decoupled models, where an independent parameterization is used for each property. We apply the algorithm to three 1-D geophysical inverse problems, using both synthetic and field data. For the synthetic cases, we compare the SD algorithm to standard Markov chain Monte Carlo and reversible-jump Markov chain Monte Carlo approaches that use either fully coupled or fully decoupled parameterizations. In case of coupled structures, the SD algorithm does not behave differently from methods that assume common interfaces. In case of decoupled structures, the SD approach is demonstrated to correctly retrieve the portion of profiles where the physical properties do not share the same structure. The application of the new algorithm to field data demonstrates its ability to decouple structures where a common stratification is not supported by the data.

Partial nephrectomy versus ablative therapy for the treatment of renal tumors in an imperative setting.

PURPOSE: To compare partial nephrectomy (PN) and percutaneous ablative therapy (AT) for renal tumor in imperative indication of nephron-sparing technique (NST). MATERIALS AND METHODS: Between 2000 and 2015, 284 consecutive patients with a kidney tumor in an imperative indication of NST were retrospectively included in a multicenter study. PN [open (n = 146), laparoscopic (n = 9), or robotic approach (n = 17)] and AT [radiofrequency ablation (n = 104) or cryoablation (n = 8)] were performed for solitary kidney (n = 146), bilateral tumor (n = 78), or chronic kidney disease (CKD) (n = 60). RESULTS: Patients in the PN group had larger tumors and a higher RENAL score. There were no differences between the two groups with respect to age, reasons for imperative indication, and preoperative eGFR. Patients in the AT group had a higher ASA and CCI. PN had worse outcomes than AT in terms of transfusion rate, length of stay, and complication rate. Local radiological recurrence-free survival was better for PN, but metastatic recurrence was similar. Percentage of eGFR decrease was similar in the two groups. Temporary or permanent dialysis was not significantly different. On multivariate analysis, PN and AT had a similar eGFR change when adjusted for tumor complexity, reason of imperative indication and CCI. CONCLUSION: In imperative indication of nephron-sparing treatment for a kidney tumor, either PN or AT can be proposed. PN offers the ability to manage larger and more complex tumors while providing a better local control and a similar renal function loss.

Using Benford's law to investigate Natural Hazard dataset homogeneity.

Working with a large temporal dataset spanning several decades often represents a challenging task, especially when the record is heterogeneous and incomplete. The use of statistical laws could potentially overcome these problems. Here we apply Benford's Law (also called the "First-Digit Law") to the traveled distances of tropical cyclones since 1842. The record of tropical cyclones has been extensively impacted by improvements in detection capabilities over the past decades. We have found that, while the first-digit distribution for the entire record follows Benford's Law prediction, specific changes such as satellite detection have had serious impacts on the dataset. The least-square misfit measure is used as a proxy to observe temporal variations, allowing us to assess data quality and homogeneity over the entire record, and at the same time over specific periods. Such information is crucial when running climatic models and Benford's Law could potentially be used to overcome and correct for data heterogeneity and/or to select the most appropriate part of the record for detailed studies.

Complications associated with photoselective vaporization of the prostate: categorization by a panel of GreenLight users according to Clavien score and report of a single-center experience.

OBJECTIVE: To devise and validate a system to categorize GreenLight photoselective vaporization of prostate (PVP) complications according to Clavien score (CS), to report complications of PVP using this categorization, and to determine risk factors. MATERIALS AND METHODS: A survey questionnaire was distributed to all participants of the second meeting of the Group of GreenLight Users. They were asked to grade PVP complications according to CS. We calculated the mode CS for each complication from the survey data to propose a categorization system for complications of PVP. Complications encountered in a large single-center cohort of 370 patients were reported according to this system. We assessed the reproducibility of CS by estimating inter-rater agreement by the Fleiss kappa. We performed univariate and multivariate analyses to determine risk factors for complications. RESULTS: Of the 67 meeting participants, 42 (62.7%) completed the survey. Overall agreement between urologists was fair (Fleiss kappa = 0.356). Among the 370 patients, 21 (5.7%) had intraoperative complications, 147 (39.7%) had postoperative complications, and 70 (18.9%) had long-term complications. Among the postoperative complications, 125 patients (33.8%) were classified as Clavien grade I, 58 (15.7%) as Clavien grade II, 4 (1.1%) as Clavien grade IIIb, 5 (1.3%) as Clavien grade IVa, 1 (0.3%) as Clavien grade IVb, and 1 (0.3%) as Clavien grade V. In multivariate analysis, the only predictor of overall complications was a polymicrobial preoperative urine culture. CONCLUSION: The grading of PVP complications by CS is fairly reproducible. We are the first to propose a system for the categorization of PVP complications. PVP complications are frequent but most often minor.

Penetration depth with the XPS GreenLight laser assessed by contrast enhanced ultrasonography.

PURPOSE: The GreenLight laser is one of the main alternative treatments for benign prostatic hyperplasia (BPH). Ultrasonography with contrast (ECUS) is one of the main innovations in radiology that has led to the examination of tissue vascularity. The objective of the study was to measure the impact of photovaporization of the prostate (PVP) on the prostate gland with ECUS. PATIENTS AND METHODS: We conducted a pilot study to assess the impact of PVP on the prostate by using ECUS intraoperatively (ethical committee approval No. 2012-001451-39). Twelve patients undergoing PVP for symptomatic BPH were enrolled in this study after providing their informed consent. ECUS was performed just before and after PVP in the operating room and at 1 month postoperatively. RESULTS: Comparative analysis showed that after PVP, a nonvascularized area with an average thickness of 11.1 mm was observed beyond the operative cavity. The nonvascularized area was thinner at 1 month postoperatively and disappeared at 6 months for the six patients evaluated. This is the first study using contrast-enhanced ultrasonography to measure the impact of PVP on the prostate. Our study has the limitations of a pilot study with a small population and a short follow-up. Based on these results, we would advise beginners to take into account the necrosis thickness and to limit the depth of vaporization. CONCLUSIONS: Through the use of ECUS, our study demonstrated that a large area of necrosis is induced around the surgical cavity from the action of the GreenLight laser. Being aware of this phenomenon will certainly reduce the risk of complications induced by surgery.

Reconstructing plate-motion changes in the presence of finite-rotations noise.

Understanding lithospheric plate motions is of paramount importance to geodynamicists. Much effort is going into kinematic reconstructions featuring progressively finer temporal resolution. However, the challenge of precisely identifying ocean-floor magnetic lineations, and uncertainties in geomagnetic reversal timescales result in substantial finite-rotations noise. Unless some type of temporal smoothing is applied, the scenario arising at the native temporal resolution is puzzling, as plate motions vary erratically and significantly over short periods (<1 Myr). This undermines our ability to make geodynamic inferences, as the rates at which forces need to be built upon plates to explain these kinematics far exceed the most optimistic estimates. Here we show that the largest kinematic changes reconstructed across the Atlantic, Indian and South Pacific ridges arise from data noise. We overcome this limitation using a trans-dimensional hierarchical Bayesian framework. We find that plate-motion changes occur on timescales no shorter than a few million years, yielding simpler kinematic patterns and more plausible dynamics.

The role of American Society of Anesthesiologists scores in predicting urothelial carcinoma of the upper urinary tract outcome after radical nephroureterectomy: results from a national multi-institutional collaborative study.

UNLABELLED: Study Type--Prognosis (cohort) Level of Evidence 2b. What's known on the subject? and What does the study add? Upper urinary tract urothelial carcinoma (UUT-UC) is a rare disease, usually treated by nephroureterectomy, occurring in a population with a median age of 70 years and with frequent tobacco use and other comorbidities. We know that the American Society of Anesthesiologists (ASA) score has prognostic value in urological oncology but this has not been assessed in UUT-UC. Using a multi-institutional French database, we have shown that the 5-year cancer-specific survival differed significantly between ASA 1, ASA 2 and ASA 3 patients (83.8%, 76.9% and 70.6%, respectively; P = 0.01). ASA status had a significant impact on cancer-specific survival in univariate and multivariate analyses, with a threefold higher risk of mortality at 5 years for ASA 3 compared with ASA 1 patients (P = 0.04). OBJECTIVE: • To evaluate the impact of American Society of Anesthesiologists (ASA) scores on the survival of patients treated with radical nephroureterectomy (RNU) for upper urinary tract urothelial carcinoma (UUT-UC). PATIENTS AND METHODS: • A retrospective multi-institutional cohort study of the French collaborative national database of UUT-UC treated by RNU in 20 centres from 1995 to 2010. • The influence of age, gender and ASA score on survival was assessed using a univariable and multivariable Cox regression analysis with pathological features used as covariables. RESULTS: • Overall, 554 patients were included. The median follow-up was 26 months (10-48 months), and the median age was 69.5 years (61-76 years). In total, 114 (20.6%) patients were classified as ASA 1, 326 (58.8%) as ASA 2 and 114 (20.6%) as ASA 3. • The 5-year recurrence-free survival (P = 0.21) and metastasis-free survival (P = 0.22) were not significantly different between ASA 1 (52.8% and 76%), ASA 2 (51.9% and 75.3%) and ASA 3 patients (44.1% and 68.2%, respectively). • The 5-year cancer-specific survival differed significantly between ASA 1, ASA 2 and ASA 3 patients (83.8%, 76.9% and 70.6%, respectively; P = 0.01). • ASA status had a significant impact on cancer-specific survival in univariate and multivariate analyses, with a threefold higher risk of mortality at 5 years for ASA 3 compared with ASA 1 patients (P = 0.04). CONCLUSIONS: • ASA classification correlates significantly with cancer-specific survival after RNU for UUT-UC. • It is a further pre-operative clinical variable that can be incorporated into future risk prediction tools for UUT-UC to improve their accuracy.

Influence of photoselective vaporization of the prostate on sexual function: results of a prospective analysis of 149 patients with long-term follow-up.

BACKGROUND: Even though transurethral resection of the prostate remains the gold standard treatment for lower urinary tract symptoms (LUTS) refractory to medical therapy, photoselective vaporization of the prostate (PVP) has become a popular alternative. Early PVP studies seem encouraging, but few data exist regarding the effect of PVP on sexual function at long-term follow-up. OBJECTIVE: Our aim was to evaluate the impact of PVP on erectile function (EF) at long-term follow-up in men with LUTS due to benign prostatic hyperplasia (BPH). DESIGN, SETTING, AND PARTICIPANTS: One hundred forty-nine consecutive patients who underwent a prostate vaporization with the GreenLight laser performed by a single surgeon (FB) were prospectively enrolled in this study. INTERVENTION: All patients underwent PVP with the GreenLight laser performed by one experienced surgeon. MEASUREMENTS: All patients were evaluated by International Index of Erectile Function (IIEF-5) preoperatively and at 1, 3, 6, and 12 mo and then once a year. At each visit, the questionnaires were collected, and each patient's maximum flow rate and postvoid residual volume were measured with ultrasound. Biologic data were also collected at each visit, including prostate-specific antigen, creatinine, and bacterial urine culture. RESULTS AND LIMITATIONS: One hundred forty-nine patients were enrolled in the study. Median patient age was 74 yr. Urinary function was significantly improved over baseline in both men with normal or abnormal preoperative erectile function. Energy used was 255+/-129kJ. Hospitalization stay was 2.2+/-3.1 d. Other than a temporary difference at 1 yr, IIEF-5 scores were comparable preoperatively and postoperatively if we consider all the population. However, considering patients with preoperative IIEF-5 >19, the postoperative IIEF-5 scores were significantly decreased at 6, 12, and 24 mo. CONCLUSIONS: Sexual function appears to be maintained after PVP; however, in patients with normal preoperative EF, we showed a significant decrease in EF after PVP.

Decomposition of the laboratory gamma irradiation component of angular ESR spectra of fossil tooth enamel fragments.

Spectrum decomposition of the angular measurements of fossil tooth enamel fragments using an automated simulated annealing (SA) procedure shows that the mix CO(2)(-) radicals generated by laboratory irradiation is significantly different to that of the natural sample. The naturally irradiated sample contains about 10% of non-oriented CO(2)(-) radicals and a mix of 35:65 orthorhombic to axial CO(2)(-) radicals. In contrast, laboratory irradiation generated about 40% of non-oriented radicals and a large amount of orthorhombic CO(2)(-) radicals, while we failed to detect any axial CO(2)(-) radicals. The results indicate that geological aging of the sample incurs various annealing and transfer processes; their precise nature is yet unknown. Nevertheless, the understanding of the formation and transfer processes that leads to the observed mix of CO(2)(-) radicals in fossil tooth enamel is essential for the reliable application of ESR dating.