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The actively spreading Chile Ridge has been subducting beneath Patagonian Chile since the Middle Miocene. After subduction, continued separation of the faster Nazca plate from the slow Antarctic plate has opened up a gap--a slab window--between the subducted oceanic lithospheres beneath South America. We examined the form of the asthenospheric mantle flow in the vicinity of this slab window using S waves from six isolated, unusual 2007 earthquakes that occurred in the generally low-seismicity region just north of the ridge subduction region. The S waves from these earthquakes were recorded at distant seismic stations, but were split into fast and slow orthogonally polarized waves at upper mantle depths during their passage through the slab window and environs. We isolated the directions of fast split shear waves near the slab window by correcting for upper mantle seismic anisotropy at the distant stations. The results show that the generally trench-parallel upper mantle flow beneath the Nazca plate rotates to an ENE trend in the neighborhood of the slab gap, consistent with upper mantle flow from west to east through the slab window. doi: 10.1130/G30920.1

The average depth of crustal and upper mantle compensation interfaces are obtained from the power spectra of free air gravity anomalies in the eastern Caribbean-South American plate boundary zone. The inferable regional structures are associated with the crustal and upper mantle of the foreland basin. The foreland basin is not associated with the detaching oceanic subducted slab.

Shear-wave splitting of S and SKS phases reveals that anisotropy and s train field of the mantle beneath the subducting Nasca plate, Cocos plate, and the Caribbean region. These observations can be used to test models of mantle flow. Two-dimensional entrained mantle flow beneath the subducting Nazca slab is not consistent with the data Rather, there is evidence of horizontal trench-parallel flow in the mantle beneath the Nazca plate along much of the Andean subduction zone. Trench-parallel flow is attributable to retrograde motion of the slab, the decoupling of the slab and underlying mantle, and a partial barrier to flow at depth, resulting in lateral mantle flow beneath the slab. Such flow facilities the transfer of material from the shrinking mantle reservoir beneath the Pacific basin to the growing mantle reservoir beneath the Atlantic basin. Trench-parallel flow may explain the eastward motions of the Caribbean and Scotia sea plates, the anomalously shallow bathymetry of the eastern Nazca plate, the long-wavelength geoid high over western South America, and it may contribute to the high elevation and intense deformation of the central Andes., One of the most important implications of the plate tectonic revolution is that the mantle is convecting; yet progress in the characterization of mantle flow over the subsequent decades has [...]

Our studies of the surface structures, seismicity, and gravity anomalies of the Caribbean-South American plate-boundary zone of northeast Venezuela and Trinidad show that the crystal and upper lithospheric structure and kinematics of this zone are complex and differ markedly along strike. We propose a model of the zone's lateral transition from near Trinidad west to Caracas, emphasizing three concepts: (1) the steepening, detachment, and then sinking away of Atlantic oceanic lithosphere that is (was) attached to the northern edge of continental South America; (2) the wedging seaward and imbricate thickening of the northern margin of the continent in the region of the detaching Atlantic slab; the continental wedge overrides the slab and is overridden by terranes attached to the Caribbean plate; and (3) that the structural and kinematic transitions are a consequence of the progressive oblique collision between continental South America and the overriding Caribbean terranes.

Introduction: Despite considerable debate in the medical literature about the educational utility of pharmaceutical representatives (PR), little is known about their attitudes towards their role as marketers and/or educators, their ability to provide comprehensive information about products and their learning needs. Design: A survey. Subjects and Method: Questionnaires were mailed to 606 PRs from five Canadian pharmaceutical companies. Results: Of 309 (51%) respondents, 98% strongly agreed or agreed they had a role in educating doctors, while 52% strongly disagreed or disagreed their main goal was marketing. Overall, 92% agreed they had received adequate training to perform a well-informed detail, and 96% reported the information they provide is accurate. The majority (66%) felt a university-accredited program would improve the quality of their detailing. Conclusion: Most PRs believe their main goal is education. Despite most reporting that they had received adequate training, they felt that a university-accredited educational program would improve the quality of detailing. The number of years that a PR spent in the industry appears to have an effect on how they perceive their role. [ABSTRACT FROM AUTHOR]

Simple Summary: Cotesia ruficrus (Haliday) (Hymenoptera: Braconidae) is a native enemy of the important invasive fall armyworm pest, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), in China, exhibiting significant pest control capabilities. To investigate the impact of Cotesia ruficrus on the gut bacteria of fall armyworm caterpillars following parasitism, we used 16S rRNA sequencing technology to analyze the diversity and richness of gut bacteria in both long-term and short-term laboratory fall armyworm caterpillars. Our study reveals that Cotesia ruficrus parasitism induces changes in fall armyworm larval gut microbiota, thereby shedding light on the capacity of parasitoid parasitism to impact host gut microbiota. These findings lay the foundation for deeper exploration of the gut microbiota's role in the parasitoid–host interaction mechanism. Parasitoids have the potential to alter the gut microbiota of their host insects post-parasitization, thereby influencing the host's physiological functions and creating a more favorable environment for the survival of the parasitoid's progeny. Cotesia ruficrus is a native enemy of the important invasive fall armyworm (FAW) pest, Spodoptera frugiperda, in China, exhibiting significant pest control capabilities. To investigate the impact of C. ruficrus on the gut bacteria of FAW caterpillars following parasitism, we used 16S rRNA sequencing technology to analyze the diversity and richness of gut bacteria in both long-term laboratory and short-term laboratory FAW caterpillars. The results revealed Enterococcus as the predominant bacteria across all treatments, while no significant differences were observed in the diversity and richness of gut bacteria between non-parasitized and parasitized long-term laboratory FAW caterpillars. Similarly, while the diversity of gut bacteria in non-parasitized and parasitized short-term laboratory FAWs showed no significant variance, a marked discrepancy in richness was noted. Moreover, the richness of gut bacteria in short-term laboratory FAW caterpillars surpassed that of their long-term laboratory counterparts. In addition, it was found that Corynebacterium existed only in the intestinal tract of FAW caterpillars that were parasitized by C. ruficrus. These results substantiate that C. ruficrus parasitization can alter the gut microbiota of FAW caterpillars, providing valuable insights into the interplay between gut microbiota and the dynamics of parasitoid–host interactions. [ABSTRACT FROM AUTHOR]

Rotating detonation engines (RDEs), which are Humphrey cycle-based constant-volume combustion engines, utilize detonation waves to attain higher efficiencies compared with conventional constant-pressure combustion engines through pressure gain. Such engines have garnered significant interest as future propulsion technologies, and thus, numerous research and development initiatives have been launched specific to RDEs in various forms. This paper presents a survey of research and development trends in RDE operating systems, based on experimental studies conducted worldwide since the 2010s. Additionally, a performance comparison of RDEs developed to date is presented. [ABSTRACT FROM AUTHOR]

Examines the link between the opening of ocean basins and cordillera formation and between ocean basins and marginal basin formation in the Andes Region. Cordillera and marginal basin formation as consequences of the Wilson cycle; Mantle anisotropy; Displacement of the mantle; Sea-floor spreading.

The selection of an appropriate ridge parameter plays a crucial role in ridge estimation. A smaller ridge parameter leads to larger residuals, while a larger ridge parameter reduces the unbiasedness of the estimation. This paper proposes a constrained L-curve method to accurately select the optimal ridge parameter. Additionally, the constrained L-curve method, traditional L-curve method, and ridge trace method are individually coupled with the system differential response curve to update the streamflow in the Jianyang Basin using the SWAT model. Multiple evaluation criteria are employed to analyze the efficacy of the three methods for correction. The results demonstrate that the constrained L-curve method accurately identifies the optimal ridge parameter in the actual model. Furthermore, the coupling of the constrained L-curve method with the system differential response curve exhibits markedly superior accuracy of simulated streamflow compared to the traditional L-curve and ridge trace methods, with the mean Nash–Sutcliffe efficiency (NSE) improving from 0.71 to 0.88 after correction. The constrained L-curve method, which incorporates the physical interpretation of the estimated parameters, effectively identifies the optimal ridge parameter in practical scenarios. As a result, it demonstrates superior usability and applicability when compared to the traditional L-curve method. [ABSTRACT FROM AUTHOR]

The Southern Patagonian Icefield (SPI) is the largest continuous ice mass in the Southern Hemisphere outside Antarctica. It has been shrinking since the Little Ice Age (LIA) period, with increasing rates in recent years. An uplift of crustal deformation in response to this deglaciation process has been expected. The goal of this investigation is to analyze the crustal deformation caused by ice retreat using time-series data from continuous GPS stations (2015–2020) in the northern area of the SPI. For this purpose, we installed two continuous GPS stations on rocky nunataks of the SPI (the GRCS near Greve glacier and the GBCS close by Cerro Gorra Blanca). In addition, ice elevation changes (2000–2019) were analyzed by the co-registration of the SRTM digital elevation model and ICESat elevation data points. The results of the vertical components are positive (36.55 ± 2.58 mm a−1), with a maximum at GBCS, indicating the highest rate of crustal uplift ever continuously recorded in Patagonia; in addition, the mean horizontal velocities reached 11.7 mm a−1 with an azimuth of 43°. The negative ice elevation changes detected in the region have also accelerated in the recent two decades, with a median Δ h (elevation change) of −3.36 ± 0.01 m a−1 in the ablation zone. The seasonality of the GPS signals was contrasted with the water levels of the main Patagonian lakes around the SPI, detecting a complex interplay between them. Hence, the study sheds light on the knowledge of the crustal uplift as evidence of the wastage experienced by the SPI glaciers. [ABSTRACT FROM AUTHOR]

We use new GPS data to determine an updated Euler pole describing the present-day motion of the oceanic Nazca Plate. Our solution includes continuous GPS (cGPS) measurements at Malpelo Island offshore Colombia, two sites in the Galapagos archipelago, Easter Island and Salas y Gomez Island in the western part of the plate and Robinson Crusoe Island offshore Chile. A careful analysis of geodetic time-series reveals that (1) previous estimates using former cGPS site EISL are biased by several millimetres per year eastward due to station malfunctioning (2) north velocity component of cGPS site GLPS at Santa Cruz Island in the Galapagos is impacted by volcanic deformation at the 1–2 mm yr–1 level, probably caused by the recurrent volcanic activity of the Sierra Negra volcano. In addition, we find shortening at ∼1 mm yr–1 between Easter Island (cGPS ISPA) and Salas y Gomez Island (cGPS ILSG), consistent with the elastic deformation induced by rapid opening at the East Pacific rise. cGPS site at Robinson Crusoe Island shows ∼4–5 mm yr–1 abnormally fast East velocity induced by the visco-elastic relaxation following the Maule M w 8.8 2010 earthquake. Using this information, we determine a new Euler pole (longitude: –90.93°E, latitude 56.19°N, 0.588 deg Myr–1) describing the present-day Nazca–South America Plate motion, using five sites (Malpelo Island, two sites in the Galapagos archipelago, Easter Island and Salas y Gomez Island). The proposed Euler pole provides a weighted root mean square (wrms) of residual velocities of 0.6 mm yr–1, slightly higher than usually observed for other major tectonic plates and accounting for the uncertainty of potential volcanic–tectonic deformation. Our model predicts a maximum convergence rate at 65.5 ± 0.8 mm yr–1 at latitude ∼30°S along the Chile trench, decreasing to 50.8 ± 0.7 mm yr–1 in northern Colombia and 64.5 ± 0.9 mm yr–1 in southern Chile (1 σ confidence level). Comparison with the geological models NUVEL1A and MORVEL indicates constant decrease since 3.16 Ma of opening rate along the Nazca–Antarctic Plate boundary spreading centres at ∼1 cm yr–1 per Myr. Combined with the ITRF2014 pole for the Pacific and Antarctic plates, our derived Euler pole predicts closure at the ∼1 mm yr–1 level for Pacific–Antarctic–Nazca Plate circuit. However, combining our results with MORVEL estimates for the Cocos Plate, the non-closure of the Pacific–Cocos–Nazca Plate circuit is 9.7 ± 1.6 mm yr–1, 30 per cent lower than the 14 ± 5 mm yr–1 reported in MORVEL model, but still significant. A small (∼1.5 mm yr–1) velocity residual at Malpelo Island neither supports the hypothesis of an independent Malpelo microplate offshore Colombia nor large scale internal deformation induced by thermal contraction. Our solution rather suggests that non-closure of the Pacific–Cocos–Nazca Plate circuit arises from the determination of the Cocos Plate motion in MORVEL, an hypothesis further supported by the large discrepancy between MORVEL's prediction and the observed GPS velocity observed at Cocos Islands (cGPS ISCO). [ABSTRACT FROM AUTHOR]

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/− lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/− upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps. [ABSTRACT FROM AUTHOR]

This paper presents a cartographic framework based on algorithms of GMT codes for mapping seismically active areas in Venezuela. The data included raster grids from GEBCO, EGM-2008, and vector geological layers from the USGS. The data were iteratively processed in the console of GMT, converted by GDAL, formatted, and mapped for geophysical data visualisation; the QGIS was applied for geological mapping. We analyzed 2000 samples of the earthquake events obtained from the IRIS seismic database with a 25-year time span (1997–2021) in order to map the seismicity. The approach to linking geological, topographic, and geophysical data using GMT scripts aimed to map correlations among the geophysical phenomena, tectonic processes, geological setting, seismicity, and earthquakes. The practical application of the GMT scripts consists in automated mapping for the visualization of geological risks and hazards in the mountainous region of the Venezuelan Andes. The proposed method integrates the approach of GMT scripts with state-of-the-art GIS techniques, which demonstrated its effectiveness as a tool for mapping spatial datasets and rapid data processing in an iterative regime. In this context, using GMT and GIS to find similarities between the regional earthquake distribution and the geological and topographic setting is essential for hazard risk assessment. This study can serve as a basis for predictive seismic analysis in geologically vulnerable regions of Venezuela. In addition to a technical demonstration of GMT algorithms, this study also contributes to geological and geophysical mapping and seismic hazard assessments in South America. We present the full scripts used for mapping in a GitHub repository. [ABSTRACT FROM AUTHOR]

In 2016 the Senior Managers and Certification Regime (SMCR) came into being. It sought to improve banking culture through the attribution of responsibility to individuals and to provide clarity on required conduct standards. It marked a shift away from collective responsibility and towards more individual accountability that had been so lacking following the financial crisis of 2007/08. Its scope is expansive, including not just board executives but also senior managers. In this paper, I question whether there are indications the SMCR is achieving its objective of 'changing banking for good'. I do this by analysing the design of the SMCR and its application in practice as well as the meaning and regulatability of culture. I conclude that though the SMCR could make strides towards better banking culture, its potential is being curtailed by inconsistent messaging and irresolute application. [ABSTRACT FROM AUTHOR]

Simple Summary: The Egyptian honeybee (Apis mellifera lamarckii) is one of the honeybee subspecies known for centuries since the ancient Egypt civilization. The subspecies of the Egyptian honeybee is distinguished by certain traits of appearance and behavior that were well-adapted to the environment and unique in a way that it is resistant to bee diseases, such as the Varroa disease. The subspecies is different than those found in Europe and is native to southern Egypt. Therefore, a special care should be paid to the vulnerable A. m. lamarckii subspecies and greater knowledge about the risk factors as well as conservation techniques will protect these bees. Additionally, more qualitative and quantitative measures will be taken to obtain deep insights into the A. m. lamarckii products' chemical profile and biological characters. Egypt has an ongoing long history with beekeeping, which started with the ancient Egyptians making various reliefs and inscriptions of beekeeping on their tombs and temples. The Egyptian honeybee (Apis mellifera lamarckii) is an authentic Egyptian honeybee subspecies utilized in apiculture. A. m. lamarckii is a distinct honeybee subspecies that has a particular body color, size, and high levels of hygienic behavior. Additionally, it has distinctive characteristics; including the presence of the half-queens, an excessive number of swarm cells, high adaptability to climatic conditions, good resistance to specific bee diseases, including the Varro disorder, and continuous breeding during the whole year despite low productivity, using very little propolis, and tending to abscond readily. This review discusses the history of beekeeping in Egypt and its current situation in addition to its morphology, genetic analysis, and distinctive characters, and the defensive behaviors of native A. m. lamarckii subspecies. [ABSTRACT FROM AUTHOR]

Early Carboniferous granitoids, distributed in the Yining and Central Tianshan blocks, Chinese western Tianshan, are important for deciphering their tectonic contexts and evolutionary history of the South Tianshan Ocean. Here we present LA-ICP-MS zircon U-Pb ages, in situ Hf isotopic data, and whole-rock geochemical data of the monzogranites and syenogranites from the Kalejun Mountains, southern part of the Yining Block, aiming to constrain their petrogenesis and geodynamic background. The results reveal that these monzogranites and syenogranites were emplaced at 356 Ma and 344 Ma, respectively. Geochemically, they are characterized by high SiO2 (68.74–75.76 wt.%) and K2O (4.58–6.18 wt%), low MgO (0.14–0.76 wt.%) and P2O5 (0.04–0.24 wt.%) contents. In addition, they are depleted in Ba, Sr, Eu, Ti, Nb, and Zr, and enriched in Rb, Cs, Th, and U. These features indicate that the Kalejun granites are high-silica I-type granites. The low positive εHf(t) values (+1.1 to +8.2) and old T D M 2 H f model ages (1294 to 827 Ma) of the studied zircons imply that the parental magma of these granites were derived from the reworking of Proterozoic basement with minor involvement of juvenile materials. Combined with the Late Devonian to Early Carboniferous magmatic activities in the Yining and Central Tianshan blocks (e.g. the discovery of A-type bubble rhyolites and high-Mg andesites), it is suggested that the Kalejun granites were likely related to the roll-back of the South Tianshan oceanic slab. Finally, we argue that the subduction of South Tianshan Ocean probably terminated at the end of the Early Carboniferous. [ABSTRACT FROM AUTHOR]

Many articles have demonstrated that extracellular neutrophil traps (NETs) are often described as part of the antibacterial function. However, since the components of NETs are non-specific, excessive NETs usually cause inflammation and tissue damage. Endothelial dysfunction (ED) caused by NETs is the major focus of tissue damage, which is highly related to many inflammatory diseases. Therefore, this review summarizes the latest advances in the primary and secondary mechanisms between NETs and ED regarding inflammation as a mediator. Moreover, the detailed molecular mechanisms with emphasis on the disadvantages from NETs are elaborated: NETs can use its own enzymes, release particles as damage-associated molecular patterns (DAMPs) and activate the complement system to interact with endothelial cells (ECs), drive ECs damage and eventually aggravate inflammation. In view of the role of NETs-induced ED in different diseases, we also discussed possible molecular mechanisms and the treatments of NETs-related diseases. [ABSTRACT FROM AUTHOR]

The honeybee Apis mellifera is highly appreciated worldwide because of its products, but also as it is a pollinator of crops and wild plants. The beehive is vulnerable to infections due to arthropods, fungi, protozoa, bacteria and/or viruses that manage to by-pass the individual and social immune mechanisms of bees. Due to the close proximity of bees in the beehive and their foraging habits, infections easily spread within and between beehives. Moreover, international trade of bees has caused the global spread of infections, several of which result in significant losses for apiculture. Only in a few cases can infections be diagnosed with the naked eye, by direct observation of the pathogen in the case of some arthropods, or by pathogen-associated distinctive traits. Development of molecular methods based on the amplification and analysis of one or more genes or genomic segments has brought significant progress to the study of bee pathogens, allowing for: (i) the precise and sensitive identification of the infectious agent; (ii) the analysis of co-infections; (iii) the description of novel species; (iv) associations between geno- and pheno-types and (v) population structure studies. Sequencing of bee pathogen genomes has allowed for the identification of new molecular targets and the development of specific genotypification strategies. [ABSTRACT FROM AUTHOR]

This article critically interrogates the experience of the implementation and enforcement of the Senior Managers and Certification Regime (SMCR) in light of interdisciplinary literature on organisational culture. We demonstrate that the SMCR brings the promise of enhancing effective regulatory supervision of firm culture, supporting the incipient professionalisation of senior manager functions in the financial sector and discerning tangible aspects of artefacts and behaviours that constitute the external layer of good culture. However, we argue that, apart from the more obvious risk of too little enforcement or enforcement targeted at misconduct in the private sphere, there is a risk that a perception of rigidity in enforcement may lead to the development of a counterproductive culture, especially if firms unduly rely upon tick-box quantitative measurement approaches to culture management, and that sound culture may be simplistically equated to compliance with the SMCR. This necessitates a careful and nuanced approach to supervision. [ABSTRACT FROM AUTHOR]

Blunt cerebrovascular injury (BCVI) is an often underrecognized injury occurring in the carotid or vertebral arteries, associated with a risk of ischemic stroke and potential for poor neurological outcome or death. Computed tomographic angiography (CTA) is the most common modality for initial screening and diagnosis. Vessel wall intimal injuries, intraluminal thrombus, dissection, intramural hematoma, pseudoaneurysm, vessel transection, and arteriovenous fistula, are potential findings to be considered in approach to imaging. Identification of high-risk trauma patients based on clinical and radiological risk factors can determine patients at risk of BCVI for targeted screening. [ABSTRACT FROM AUTHOR]

The eastern offshore of Martinique is one of the active areas of the Lesser Antilles Subduction Zone (LASZ). Although its seismicity is moderate compared to other subduction zones, LASZ is capable of generating a M  7+ interplate earthquake and recent studies and historical events, such as the M 8 1839 and M  7–7.5 1946 earthquakes, confirm this possibility. Given the high risk that Martinique can face in case of unpreparedness for such a M  7+ earthquake, and the lack of a regional seismic hazard study, we investigated through numerical modelling how ground motion can vary for a hypothetical M w 7.5 interplate earthquake. Our main objective is to highlight the major factors related to earthquake source that can cause the highest variation in ground motion at four broad-band seismic stations across Martinique. For this purpose, we generated 320 rupture scenarios through a fractal kinematic source model, by varying rupture directivity, source dimension, slip distribution. We computed the broad-band ground motion (0.5–25 Hz) by convolution of source–time functions with empirical Green's functions (EGFs), that we selected from the analysis of moderate events (M  4–4.5) recorded in the area of interest since 2016 by the West Indies network. We found that the fault geometry and the spatial extension of the largest slip patch are the most influential factors on ground motion. The significance of the variation of the predicted ground motion with respect to ground motion prediction equations (GMPEs) depends on the evaluated frequency of ground motion and on the station. Moreover, we concluded that the EGF selection can be another significant factor controlling the modelled ground motion depending on station. Our results provide a new insight for the seismic source impact on ground motion across Martinique and can guide future blind seismic hazard assessment studies in different regions. [ABSTRACT FROM AUTHOR]

Rotating detonation engines (RDEs) have been observed to exhibit several operating modes and instabilities under different operation conditions (reactant mixture, injection pressure, engine geometry, injection mass flow rate, etc.). We develop the simplest model possible describing the operation of an RDE. This model takes into account the dependence of detonation properties on engine conditions, the injection process, and the geometric constraints. Using this model, we predict the lowest allowable reactant injection rates that allow an RDE to operate with a single detonation wave propagating in the annular combustion chamber. This model is compared with experimental results of engines running on H 2 /O 2 and C 2 H 4 /O 2 . [ABSTRACT FROM AUTHOR]

A rotating detonation combustor (RDC) is a novel approach to achieving pressure gain combustion. Due to the steady propagation of the detonation wave around the perimeter of the annular combustion chamber, the RDC dynamic behavior is well suited to analysis with reduced-order techniques. For flow fields with such coherent aspects, the dynamic mode decomposition (DMD) has been shown to capture well the dominant oscillatory features corresponding to stable limit-cycle or quasi-periodic behavior within its dynamic modes. Details regarding the application of the technique to RDC—such as the number of frames, the effect of subtracting the temporal mean from the processed dataset, the resulting dynamic mode shapes, and the reconstruction of the dynamics from a reduced set of dynamic modes—are analyzed and interpreted in this study. The DMD analysis is applied to two commonly observed operating conditions of rotating detonation combustion, viz., (1) a single spinning wave with weak counter-rotating waves and (2) a clapping operating mode with two counter-propagating waves at equal speed and strength. We show that care must be taken when applying DMD to RDC datasets due to the presence of standing waves (expressed as either counter-propagating azimuthal waves or longitudinal pulsations). Without accounting for these effects, the reduced-order reconstruction fails using the standard DMD approach. However, successful application of the DMD allows for the reconstruction and separation of specific wave modes, from which models of the stabilization and propagation of the primary and counter-rotating waves can be derived. [ABSTRACT FROM AUTHOR]

The Eastern Mediterranean is the most seismically active region in Europe due to the complex interactions of the Arabian, African, and Eurasian tectonic plates. Deformation is achieved by faulting in the brittle crust, distributed flow in the viscoelastic lower-crust and mantle, and Hellenic subduction, but the long-term partitioning of these mechanisms is still unknown. We exploit an extensive suite of geodetic observations to build a kinematic model connecting strike-slip deformation, extension, subduction, and shear localization across Anatolia and the Aegean Sea by mapping the distribution of slip and strain accumulation on major active geological structures. We find that tectonic escape is facilitated by a plate-boundary-like, trans-lithospheric shear zone extending from the Gulf of Evia to the Turkish-Iranian Plateau that underlies the surface trace of the North Anatolian Fault. Additional deformation in Anatolia is taken up by a series of smaller-scale conjugate shear zones that reach the upper mantle, the largest of which is located beneath the East Anatolian Fault. Rapid north–south extension in the western part of the system, driven primarily by Hellenic Trench retreat, is accommodated by rotation and broadening of the North Anatolian mantle shear zone from the Sea of Marmara across the north Aegean Sea, and by a system of distributed transform faults and rifts including the rapidly extending Gulf of Corinth in central Greece and the active grabens of western Turkey. Africa–Eurasia convergence along the Hellenic Arc occurs at a median rate of 49.8 mm yr–1 in a largely trench-normal direction except near eastern Crete where variably oriented slip on the megathrust coincides with mixed-mode and strike-slip deformation in the overlying accretionary wedge near the Ptolemy–Pliny–Strabo trenches. Our kinematic model illustrates the competing roles the North Anatolian mantle shear zone, Hellenic Trench, overlying mantle wedge, and active crustal faults play in accommodating tectonic indentation, slab rollback and associated Aegean extension. Viscoelastic flow in the lower crust and upper mantle dominate the surface velocity field across much of Anatolia and a clear transition to megathrust-related slab pull occurs in western Turkey, the Aegean Sea and Greece. Crustal scale faults and the Hellenic wedge contribute only a minor amount to the large-scale, regional pattern of Eastern Mediterranean interseismic surface deformation. [ABSTRACT FROM AUTHOR]

Knowledge of the displacement history of the series of continental fragments in Northeast Asia is key to understanding the plate kinematic evolution of the western peri-Pacific tectonic domain. Palaeomagnetism is an effective approach for deciphering the horizontal movements of crustal elements, especially vertical-axis rotations. Here we present a set of new palaeomagnetic data from Lower Cretaceous volcanic rocks from the northeastern part of the North China Block (NCB), and from Lower Cretaceous sedimentary and volcaniclastic rocks from the Bureya-Jiamusi-Khanka terrane. The data suggest that the northeastern NCB crustal elements underwent a clockwise motion relative to the Eurasian continent after the Early Cretaceous, and in addition a substantial counterclockwise deformation component is observed in the Bureya-Jiamusi-Khanka terrane. Combined with the results of previous Cretaceous and Cenozoic palaeomagnetic studies, we suggest that the northeast part of the North China Block and the Korean Peninsula experienced ~20° of clockwise rotation during the Cenozoic. However, the Bureya-Jiamusi-Khanka terrane and its eastern neighbouring Pacific-related accretionary terranes, such as the Sikhote-Alin Orogenic belt, however, underwent a contemporaneous 40°counter-clockwise rotation. The Japanese Islands, with juvenile crust in the easternmost part of Asia, were divided into a pair of terranes, which rotated in opposite directions during the Middle Miocene. The opposing senses of rotation are attributed to mantle wedge convection. We suggest that tectonic rotations of parts of Northeast Asia are controlled by the subduction of the western Pacific Plate via lithospheric deep-shallow coupling. The two critical events were coeval with ridge subduction of the Izanagi-Pacific mid-ocean ridge under the continental margin during the Palaeocene, and the collision of the Izu-Bonin and Japanese Islands during the Middle Miocene, respectively. [ABSTRACT FROM AUTHOR]

Deep slow-slip events (SSEs) at subduction zones have significantly contributed to refining our understanding of the megathrust earthquake cycle at the brittle–ductile transition. However, the specific combination of factors that determine their occurrence has not yet been fully explored. Here, we evaluate the contribution of several of these characteristics using globally mapped geophysical data that are used as proxies for physical properties of the subducting plate. This is performed by classifying 25-km-wide, trench-parallel segments into binary classes based on the observation (or lack thereof) of deep, short- or long-term SSEs. The five characteristics explored here include subducting plate age, sediment thickness, relative plate velocity, slab dip and plate surface roughness. We use these characteristics to train six machine learning models based on different learning algorithms: Gaussian Naïve Bayes, logistic regression, linear discriminant analysis, Random Forest, support vector machine and K-nearest neighbour. Short-term SSE models show that subducting plate age, relative velocity and sediment thickness have the strongest predictive power with the first two characteristics negatively correlating and sediment thickness positively correlating with SSE occurrence, respectively. These results are consistent with a conceptual model where slow slip is controlled by conditions favouring the enduring release (and possible storage) of fluids near the source region. However, the relationship between these features and elevated pore fluid pressures is not established here and further evidence is needed to validate this hypothesis. We then use a final model constructed as a weighted average of the best performing models to make predictions on the probability of SSE occurrence, with predicted short-term SSE occurrence in South America, the Aleutians, Sumatra, Vanuatu and Solomon, as well as long-term SSE occurrence in the Aleutians, Izu-Bonin, Kuril-Kamchatka, Mariana and Tonga-Kermadec. Overall, long-term SSE models do not perform as well as the short-term SSE models which may indicate that long-term SSEs are controlled by a different and/or extended set of physical characteristics than the short-term SSEs. [ABSTRACT FROM AUTHOR]

The causes of seismic anisotropy are still under debate. In particular, it is important to understand the extent to which seismic anisotropy is due to more recent geodynamic activities in the asthenosphere, or to frozen-in deformation in the lithosphere. We show that these two endmember cases can in principle be distinguished using shear-wave splitting observations from SKS waves. This is illustrated by the simple example of pure olivine with horizontal a -axis, and differing orientations of the other two axes, namely, vertical b and vertical c. The azimuthal dependence of shear-wave splitting measurements is described by two parameters, which can provide additional information about subsurface deformation. In particular, the oscillation parameter d 1 constrains the orientation of foliation. We demonstrate that shear-wave splitting in the Western and Central United States indeed shows the predicted azimuthal dependence, related to a mainly subhorizontally oriented flow plane of deformation in the upper mantle. This has important implications for asthenospheric flow. [ABSTRACT FROM AUTHOR]

Here we develop a theoretical and practical framework for the tomographic inversion of shear wave splitting intensity measurements for anisotropic structure in the upper mantle using a model space search approach. Treating the anisotropic scatterers as a first order perturbation to the background isotropic state, we implement the Born approximation to compute the integral sensitivity kernels in a finite frequency framework. We implement a parametrization of the anisotropy based on insights from olivine elasticity and fabric development that involves three parameters (corresponding to the azimuth and dip of the anisotropic symmetry axis, plus a strength parameter). Previous work on finite-frequency shear wave splitting tomography has implemented a linearization technique to invert splitting intensity data for the spatial distribution of anisotropic scatterers. The inverse problem, however, is strongly non-linear in terms of several of the involved parameters (those that describe the orientation of the symmetry axis), and their variation is not of first order. Therefore, in the case of a realistic upper mantle where anisotropic structure varies in a complicated manner, a linearization technique may not be adequate. To ameliorate these problems, we implement a model space search approach (specifically, a Markov chain Monte Carlo with Gibbs sampling algorithm) to the tomographic inversion of splitting intensity data. This approach allows for the visualization of posterior probability distributions for anisotropic parameters in the inversion. We perform a suite of synthetic resolution tests to demonstrate the reliability of our method, using a station distribution from an actual deployment of a dense seismic network. These resolution tests show that anisotropic structure may be resolved up to a length scale of roughly 50 km with teleseismic SKS waves for station spacing of 10–15 km. [ABSTRACT FROM AUTHOR]

An aborted ridge has been suggested in the Vema region, South Atlantic Ocean, and we investigate it in terms of residual gravity anomalies and half spreading rate. Gravity signature over extinct spreading centres displays residual gravity anomaly lows flanked by positive highs with systematic palaeo-spreading rate dependency. The amplitude and half-widths of the gravity lows are smaller for fast spreading rates, a relationship that has been presented for several well-constrained extinct spreading centres, such as Coral Sea and Labrador Sea, both regarded in this work for comparative purposes. The residual gravity anomalies are estimated from the removal of a long-wavelength regional trend and the gravitational effect of basement and suprabasement sources. The global sediment thickness model of NOAA is used to evaluate the sediment layer and a compaction model that fits observed density values is also considered. The basement topography is obtained from gravity field inversion and shows clearly the extinct spreading axes of the Coral Sea Basin and Labrador Sea, which are not evident from the bathymetric data set due to sedimentary deposits that lie over them. The Vema basement shows an NS structure previously suggested as the Vema Aborted Ridge (VAR), which does not coincide with the morphological feature known as the Vema Channel. Over the VAR, we have found amplitudes and half-widths in function of their half spreading rate typical from well-constrained extinct spreading centres, indicating that the structure might actually be an aborted ridge. [ABSTRACT FROM AUTHOR]

The plasticity of the mantle is still not well constrained, and satisfactory mineral-physics-based rheological laws are still missing. Despite olivine being the major component of the upper mantle, it is still debated which deformation mechanism (dislocation creep, diffusion creep, grain boundary sliding) dominates deformation. High-pressure research developments (state-of-the-art presses, synchrotron experiments, and so on) as well as competitive analysis utilities (software analysis, microscopy, and so on) allow considering intra- and intergranular mechanisms (grain boundary sliding accommodated by diffusion/dislocation creep) simultaneously. To study the contribution of individual deformation mechanism to the overall deformation in the upper mantle, we deformed polycrystalline forsterite at 3.5-5.0 GPa, 1000-1200 °C, 2 x 10[sup -5]s[sup -1] at different strains in a 6-axis Mavo press. Split-cylinder experiments allowed to characterize an "internal" surface of the sample before and after the deformation experiments. Intra- and intergranular deformation was tracked using a focus ion beam milled reference grid on this surface. Grain internal misorientation where obtained from electron backscatter diffraction (EBSD) data. Both techniques suggest the dominance of intragranular deformation, in agreement with the fact that the samples have been deformed in the dislocation creep regime, as usually defined. Moreover, strain markers and out-of-plane displacements of grains provide the first microstructural evidence for a contribution of grain boundary sliding to plastic deformation at upper mantle pressure. Whether these displacements are grain boundary sliding or involve grain boundary migration cannot be clarified, given the resolution of the strain markers. Our EBSD data suggest that grain boundary processes become increasingly relevant at temperatures above 1100 °C and ensure homogenous plastic strain distribution in the aggregate. [ABSTRACT FROM AUTHOR]