Modal Composition Research Articles

Validation of a Method for Determining the Modal Composition of a Tonal Sound Field in a Cylindrical Duct Based on Synchronous Measurements in the Duct and the Far Field in Absence of Flow

Validation of a Method for Determining the Modal Composition of a Tonal Sound Field in a Cylindrical Duct Based on Synchronous Measurements in the Duct and the Far Field in Absence of Flow

Validation of a Method for Determining the Modal Composition of a Tonal Sound Field in a Cylindrical Duct Based on Synchronous Measurements in the Duct and the Far Field in Absence of Flow

A method has been developed for determining the modal composition of correlated sound modes propagating in a cylindrical duct, the peculiarity of which is that the effect of sound reflection from the open end of the duct is taken into account by numerical or analytical calculation of the reflection coefficients. This method was validated in the TsAGI AC-2 anechoic chamber, in which the sound field was created in the duct of a small-scale air intake model using 12 speakers at fixed frequencies; the modal composition was determined using 48 microphones installed flush with the duct walls, and synchronous measurements of the directivity of sound emission from the open end of the duct in the far field were carried out. In this case, on based on the found amplitudes of sound modes in the duct, the radiation characteristics in the far field were calculated using an analytical solution for sound emission from a semi-infinite cylindrical duct, the results of which were compared with the measurement results. It is shown that the amplitudes of sound modes found according to the developed method make it possible to reconstruct the far sound field characteristics with high accuracy in cases where the number of generated propagating modes in the duct does not exceed the number of installed microphones in the cylindrical array.

Modal Decomposition of Acoustic Emissions from Pencil-Lead Breaks in an Isotropic Thin Plate.

Acoustic emission (AE) testing and Lamb wave inspection techniques have been widely used in non-destructive testing and structural health monitoring. For thin plates, the AEs arising from structural defect development (e.g., fatigue crack propagation) propagate as Lamb waves, and Lamb wave modes can be used to provide important information about the growth and localisation of defects. However, few sensors can be used to achieve the in situ wavenumber-frequency modal decomposition of AEs. This study explores the ability of a new multi-element piezoelectric sensor array to decompose AEs excited by pencil lead breaks (PLBs) on a thin isotropic plate. In this study, AEs were generated by out-of-plane (transverse) and in-plane (longitudinal) PLBs applied at the edge of the plate, and waveforms were recorded by both the new sensor array and a commercial AE sensor. Finite element analysis (FEA) simulations of PLBs were also conducted and the results were compared with the experimental results. To identify the wave modes present, the longitudinal and transverse PLB test results recorded by the new sensor array at five different plate locations were compared with FEA simulations using the same arrangement. Two-dimensional fast Fourier Transforms were then applied to the AE wavefields. It was found that the AE modal composition was dependent on the orientation of the PLB direction. The results suggest that this new sensor array can be used to identify the AE wave modes excited by PLBs in both in-plane and out-of-plane directions.

Neural network for determining an asteroid mineral composition from reflectance spectra

Context.Chemical and mineral compositions of asteroids reflect the formation and history of our Solar System. This knowledge is also important for planetary defence and in-space resource utilisation. In the next years, space missions will generate extensive spectral datasets from asteroids or planets with spectra that will need to be processed in real time.Aims.We aim to develop a fast and robust neural-network-based method for deriving the mineral modal and chemical compositions of silicate materials from their visible and near-infrared spectra. The method should be able to process raw spectra without significant pre-processing.Methods.We designed a convolutional neural network with two hidden layers for the analysis of the spectra, and trained it using labelled reflectance spectra. For the training, we used a dataset that consisted of reflectance spectra of real silicate samples stored in the RELAB and C-Tape databases, namely olivine, orthopyroxene, clinopyroxene, their mixtures, and olivine-pyroxene-rich meteorites.Results.We used the model on two datasets. First, we evaluated the model reliability on a test dataset where we compared the model classification with known compositional reference values. The individual classification results are mostly within 10 percentage-point intervals around the correct values. Second, we classified the reflectance spectra of S-complex (Q-type and V-type, also including A-type) asteroids with known Bus–DeMeo taxonomy classes. The predicted mineral chemical composition of S-type and Q-type asteroids agree with the chemical composition of ordinary chondrites. The modal abundances of V-type and A-type asteroids show a dominant contribution of orthopyroxene and olivine, respectively. Additionally, our predictions of the mineral modal composition of S-type and Q-type asteroids show an apparent depletion of olivine related to the attenuation of its diagnostic absorptions with space weathering. This trend is consistent with previous results of the slower pyroxene response to space weathering relative to olivine.Conclusions.The neural network trained with real silicate samples and their mixtures is applicable for a quantitative mineral evaluation of spectra of asteroids that are rich in dry silicates. The modal abundances and mineral chemistry of common silicates (olivine and pyroxene) can be derived with an accuracy better than 10 percentage points. The classification is fast and has a relatively small computer-memory footprint. Therefore, our code is suitable for processing large spectral datasets in real time.

Svi možemo biti pobednici - uticaj sastava tima i modaliteta prenošenja znanja na zadovoljstvo studenata poslovnih studija i performanse simulacije

Most undergraduate and graduate business programs contain a culminating capstone experience as part of the standard curriculum. So far, business capstone courses have often strived to be uniform across modalities (i.e. either online or face-to-face, they were of uniform nature) and they have been rigorous and impactful courses. Additionally, many business programs have adopted simulations or other forms of game-based learning in their capstone courses. A sample of 122 students engaged in a simulation game as part of their capstone experience was used in this study in order to examine whether modality differences did affect the students' experiences (their satisfaction with the course and performance) or not, and also whether it helped them to be on teams comprised of different business majors or not. While, on the one hand, a hypothesis that significant differences would be seen due to a different modality and group composition was initially set, the counterintuitive findings obtained during the research were indicative of the fact that students' experiences could be positive across the modalities and the varying composition so long as the instructor's efforts were directed towards rigor, engagement, and uniformity of experience in the courses.

High-Resolution Fast-Rotating Sound Localization Based on Modal Composition Beamforming and Bayesian Inversion

Rotating source beamforming techniques have been effective means of noise localization on rotary machines. In this letter, we derive an alternative expression for modal composition beamforming (MCB) and subsequently consider the equivalent source assumption and cyclostationarity of the constant angular-speed rotating sound source so that a rotating sound source power (RSP) propagation model is derived. By estimating a suitable solution for the RSP model using the subspace variational Bayesian (SVB) technique with sparsity and total variation (TV) priors, the validity of the RSP model was established. According to the simulation results, the proposed RSP-SVB method leads to a significantly higher resolution than the MCB method. It can localize multiple fast-rotating sound sources accurately, rapidly, and effectively in environments with strong background noise interference. Therefore, our proposed RSP-SVB can offer a reliable solution for identifying fast-rotating blade noise.

Petrografie a geochemie amfibolitů strážovského moldanubika

The amphibolites from the Strážov Moldanubian unit in western part of the Bohemian Massif form intercalations in metasediments of this geological unit. The Strážov Moldanubian unit forms the westernmost occurrence of Variegated group of the Moldanubian Zone. These amphibolites occur as intercalations of very different size in biotite-sillimanite, partly migmatitized paragneisses. The amphibolites were sampled in two abandoned quarries near the Svatá Kateřina and Běšiny. According to their modal composition the amphibolites occurring in quarry Radošín, near the Svatá Kateřina village, are plagioclase-bearing amphibolites with very high differences in amphibole and plagioclase ratio. The garnet is significant minor component of some amphibolites. The amphibolites occurring near of the Běšiny village form very thin, relatively long lenses as part of calc-silicate-amphibolite stromatites occurring in the central part of the Strážov Moldanubian unit. The both amphibolites are probably a metamorphic equivalent of tholeiitic volcanic rocks with tectonomagmatic features of the middle ocean ridge basalts (MORB).

Computing Elastic Moduli of Igneous Rocks Using Modal Composition and Effective Medium Theory

Elastic constants of rock materials are the basic parameters required for modeling the response of rock materials under mechanical loads. Experimental tests for determining these properties are expensive, time-consuming and suffer from a high uncertainty due to both experimental limitations and the heterogeneous nature of rock materials. To avoid such experimental difficulties, in this paper a method is suggested for determining elastic constants of rock materials by determining their porosity and modal composition and employing effective medium theory. The Voigt–Reuss–Hill average is used to determine effective elastic constants of the studied igneous rocks according to the elastic moduli of their mineral constituents. Then, the effect of porosity has been taken into account by considering rock as a two-phase material, and the Kuster–Toksoz formulation is used for providing a close estimation of different moduli. The solutions are provided for different isotropic igneous rocks. This sustainable method avoids destructive tests and the usage of energy for performing time-consuming and expensive tests and requires simple equipment.

Experimental investigation of multimodal noise generation by ducted low Mach number flows through orifice plates

Noise generation by low Mach number air flows through circular orifices in rectangular ducts is investigated. In particular, the influence of the number and position of the orifices maintaining a constant flow area is addressed. A review of the available theories suggests a certain importance of such parameters in the excitation of higher-order acoustic duct modes. A qualitative coefficient is proposed for a first characterization of the ability to enhance or lessen a given higher-order acoustic mode by the plate geometry. An experimental campaign is performed to measure the total emitted acoustic power by different plate geometries as well as its modal composition. It is found that the orifices' numbers and positions greatly influence the acoustic emissions while the flow pressure drop caused by the obstacles is similar. The proposed qualitative coefficient shows good agreement with the experimental results. A particle image velocimetry measurement campaign is performed to visualize the near-field average flow behavior upstream and downstream of the orifice plates. An increase in the turbulent velocity fluctuations in the vicinity of the orifices is observed on both sides, further validating previous studies on the subject.

Detrital zircon U-Pb geochronology of the Lunpola basin strata constrains the Cenozoic tectonic evolution of central Tibet

The Cenozoic tectonic evolution of central Tibet plays an important role in the growth of the Tibetan plateau. Paleoelevation studies show that the central Tibetan plateau hosted an east-west trending belt of basins in the Paleogene, but how they relate to the regions uplift history remains unclear. This study addresses the uplift history of the central Tibetan plateau by focusing on Lunpola basin strata deposited in the Cenozoic through detrital zircon basin provenance and zircon geochemical indicators for crustal-thickening. U-Pb dating of detrital zircon demonstrates that the Lunpola basin was mainly derived from mixed sources composed of Paleozoic–Mesozoic sedimentary rocks of the Lhasa terrane, the Cretaceous igneous rocks of the northern Lhasa terrane, and the Paleozoic–Mesozoic sedimentary rocks of southern Qiangtang terrane. The modal framework-grain composition of sandstone samples from the basin strata indicates a recycled orogen as the source. Sandstone composition analysis reveals an increase in the volcanic component with time associated with a pulse of quartz grains in the middle Eocene. We interpret such observations to indicate input from early Cretaceous clastic sediments belonging to the Duba Formation and the Baingoin Plutonic Complex, which imply passive exhumation along the hanging wall of the Gerze-Siling Co thrust. Trace element geochemistry of zircon grains demonstrates an increase in europium anomaly (Eu/Eu*), which we interpret to reflect ∼20 km crustal thickening in central Tibet from the Eocene to Oligocene, as well as an increase of >3 km surface elevation which partly was induced by the Cenozoic sedimentary accumulation. This significant uplift event may have been associated with convective removal of a thickened Tibetan lithosphere that in turn led to magmatic inflation of the Tibetan crust.

A channel sampling strategy for measurement of mineral modal and chemical composition of drill cores: application to lower oceanic crustal rocks from IODP Expedition 345 to the Hess Deep rift

Abstract. We report a new sampling strategy for collecting representative samples of drill core. By splitting the core with a diamond saw into working and archive halves, the saw cuttings constitute a “channel” sample, the best subsample from which to obtain an average mineralogical and geochemical composition of a core. We apply this procedure to sampling core of the lower oceanic crust in the Hess Deep obtained during Expedition 345 of the Integrated Ocean Drilling Program (now International Ocean Discovery Program). Our results show that particles produced by sawing range from sand to clay sizes. Sand- and silt-sized cuttings can be sampled with a spatula, whereas clay-sized particles remained in suspension after 12 h and could be collected only by settling, aided by centrifuge. X-ray diffraction (XRD) analysis and Rietveld refinement show that phyllosilicates were fractionated into the clay-sized fraction. Thus, collection of both the sedimented fraction and the clay-sized suspended fraction (commonly > 15 wt % of the total) is necessary to capture the whole sample. The strong positive correlation between the recovered sample mass (in grams) and length of core cut demonstrates that this sampling protocol was uniform and systematic, with almost 1.4 g sediment produced per centimeter of core cut. We show that major-element concentrations of our channel samples compare favorably with the compositions of billet-sized samples analyzed aboard the JOIDES Resolution, but the results show that individual billet analyses are rarely representative of the whole core recovered. A final test of the validity of our methods comes from the strong positive correlation between the loss on ignition (LOI) values of our channel samples and the H2O contents calculated from the modal mineralogy obtained by X-ray diffraction and Rietveld refinement. This sampling procedure shows that grain-sized fractionation modifies both mineralogical and chemical compositions; nevertheless, this channel sampling method is a reliable method of obtaining representative samples of bulk cores. With the ever-increasing precision offered by modern analytical instrumentation, this sampling protocol allows the accuracy of the analytical results to keep pace.

THE NATURE OF ULTRAMAFIC XENOLITHS IN THE BASALTS OF LANZAROTE ISLAND (CANARY ARCHIPELAGO)

Mineralogical and geochemical study was performed on peridotite xenolith hosted by amygdaline basalts of Lanzarote Island (Canary archipelago). Their modal composition corresponds to harzburgite. Remarkably, the petrographic composition of the rocks is marked by presence of plagioclase. The isochron shows the age of 267±35 Ma, which might be the initial stage of opening a fragment of the Atlantic Ocean. The peridotites were apparently derived in the magmatic chamber formed by "underplating" triggered by interaction of mantle substrate with the lower crust material.

Lifecycle maintenance scheduling of station with multiple categories of information

This paper studies the lifecycle maintenance scheduling of the station under variable and uncertain working conditions. In the multi-specification and small-batch production, the variable production plan leads to the piecewise constant working conditions, and then the piecewise failure process of the station. A general model based on the modality composition method is developed to generate the piecewise failure rate function of the station. To present the impacts of the working conditions on the failure process, the condition-modality theory is introduced. Based on that, an experiment for the above general model is given, and the modality fusion method for the expected failure rate modality is developed. In the maintenance scheduling with uncertain working conditions, the sharing principle is introduced to incorporate the lifecycle information into the dynamic maintenance scheduling. It is observed in the comparisons that the dynamic maintenance scheduling with the sharing principle is more cost-effective than the final payment principle and the expected maintenance scheduling. The discussion suggests that the complete equal instalment principle, which is a simplified version of the sharing principle, is applicable in the industry.

Thermodynamic modeling of melt addition to peridotite: Implications for the refertilization of the non-cratonic continental mantle lithosphere

In a classic model of evolution of the non-cratonic continental mantle lithosphere, harzburgites represent the refractory (<5% clinopyroxene) residues of high degrees of partial melting of fertile mantle, while lherzolites (>5% clinopyroxene) represent residues of lesser degrees of partial melting. However, partial melting is not the only process that could explain the peridotite compositional variability that ranges from fertile (>2 wt% Al2O3, <45 wt% MgO) to refractory (<2 wt% Al2O3, >45 wt% MgO). In the refertilization process, harzburgite is a refractory protolith (potentially previously formed by partial melting of a fertile mantle) that undergoes reactive percolation of silicate melts derived from the underlying asthenosphere, resulting in the crystallization of a new generation of minerals (mostly clinopyroxene). A simple but critical first step towards understanding the refertilization process is to examine how modal and major element compositions evolve as melts are added to peridotites. Here we use a thermodynamically-constrained two-component mixing model to independently evaluate the roles of five different parameters: pressure, temperature, redox conditions, and compositions of the initial peridotite and the added basaltic melt (hereafter referred to P-T-fO2-Xπ-Xmelt), during melt addition. We compare the results with observed suites of peridotites. The main observations are as follows: (1) the produced model is consistent with the global peridotite database, and (2) T, fO2 and small variations of pressure have almost no impact on the evolution of the system. In contrast, the mineralogy of the percolated harzburgite has a substantial effect on the variation of the modal proportions. The parameter with the most significant impact is Xmelt, which is directly linked to the geodynamic context and melting conditions. This parameter directly controls the refertilization reaction and so, the phase proportions and the bulk-rock composition. Elements that partition preferentially in the melt phase (e.g., Na) display depletions in natural assemblages that are stronger than those predicted from the simple mixing model, consistent with the fact that the natural process occurs in an open system, and that reactive percolation likely results in incompatible element enrichment in the associated melt. Our results corroborate the suggestion that most of the spectrum of compositional variability observed in lithospheric mantle peridotites can be explained by the impregnation of primitive silicate melt in refractory harzburgites.

Multimodal Monitoring of Corrosion in Reinforced Concrete for Effective Lifecycle Management of Built Facilities

Monitoring the corrosion of steel rebars is paramount to ensuring the safety and serviceability of reinforced concrete (RC) structures. Conventional electro-chemical techniques can provide an overall estimate of the extent of corrosion. However, a detailed account of the extent of corrosion would help in understanding the residual strength of corroding RC structures. A passive wave-based technique such as acoustic emissions can identify the location of corrosion but always requires the presence of transducers on the structure. In active wave-based techniques, the structure is excited through a pulse excitation and their subsequent response to this excitation is measured. Thus, for active techniques, the transducers need not always be present in the structure. In guided wave ultrasonics, the excitation pulse is imparted through a waveguide to determine the state of corrosion. This technique relies on parameters such as time of flight or attenuation of the incident signal to predict the state of corrosion. These parameters can be susceptible to uncertainties in the transducer of ultrasonic coupling. In the present study, concrete specimens with embedded steel bars have been subjected to accelerated corrosion. They have been monitored with a combination of active and passive techniques. The received signals are analyzed through a modified S-Transform-based time-frequency approach to obtain a range of modes that propagate through the specimen. The changes in the modal composition of the guided wave signals due to corrosion are parameterized and correlated to various stages of corrosion. A holistic understanding of the stages of corrosion is developed by the inclusion of acoustic emission hits to guided wave parameters. Based on the Guided Wave Ultrasonics and acoustic emission parameters, corrosion has been classified into Initiation, Intermediate, and Advanced. Subsequently, destructive tests have been performed to measure the residual strength of the corroded bars. Thus, this paper presents a novel proof of concept study for monitoring corrosion with Guided Wave Ultrasonics and acoustic emissions.

Vein and Wehrlite Formation in the Lithospheric Mantle Below the West Eifel Volcanic Field: Modelling the Effects of Pressure, Temperature and Peridotite/Melt Ratio on Magma-Peridotite Interaction Using pMELTS and a Melt Infiltration Experiment

Abstract The mantle peridotite xenoliths of the West Eifel Volcanic Field in Germany preserve evidence of multiple phases of metasomatism. The most recent metasomatic episode produced a variety of veins in the peridotite: high temperature (&amp;gt;1150°C), phlogopite–clinopyroxenite intermediate temperature (~1150°C), olivine clinopyroxenite and relatively low temperature (&amp;lt;1100°C) hornblendite together with marginal reaction zones of wehrlite and dunite. The veins and associated reaction zones have been interpreted as products of crystallization of magmas similar to those that transported the xenoliths to surface. We describe a high temperature melt infiltration experiment and thermodynamic (pMELTS) models that examine the origin of high temperature phlogopite–clinopyroxenite veins and the evolution of the wall rock adjacent to the veins and compare the result to the major and trace element signatures of the minerals in the veins. The infiltration experiment replicates the common reaction textures such as partially dissolved orthopyroxene and sieved secondary clinopyroxene that are found associated with veins. In the thermodynamic model, we calculated the equilibrium assemblages and mineral compositions for peridotite–melt mixtures ranging from peridotite only to melt only over the range of 1150 to 1350°C and 1 GPa to 2 GPa. The models reproduce the composition of vein minerals at a small peridotite/melt ratio, whereas at larger peridotite/melt ratios they produce wehrlite/dunite assemblages that are similar both in modal mineralogy and composition to the natural samples. The models show that olivine clinopyroxenite veins may have been produced at a higher pressure than the phlogopite–clinopyroxenite veins. Our models show that interaction of magma with a trace element signature indicative of a garnet-bearing source with spinel facies mantle will result in a dilution of the trace element garnet signature with little to no variation in the major oxide composition.

Magnetic Barkhausen Noise Measurements on Rocks

Context: The magnetic properties of rocks may reflect the modal abundance, composition, and microstructure of the magnetic grains contained within them, usually in a very small proportion. Magnetic Barkhausen Noise (MBN) is a non-destructive technique applied to magnetic materials, and it is very sensitive to microstructure and residual stresses. In this work, measurements of MBN in samples of rocks extracted from nature and containing varying proportions of magnetite were studied and analyzed. Method: Measurements were taken by magnetically exciting the cylindrical samples, using a magnetic yoke and measuring the induced field inside the rock as a consequence of the excitation. For the detection, a sensor coil placed on the excited surface on one of the flat faces of each cylinder was used. The signals obtained from the MBN were digitized, and a digital 5-200 kHz Butterworth filter was applied, calculating the root mean square (RMS) values. Results: The linear fit of the MBN RMS values with the increasing percentage of ferromagnetic minerals showed an increasing trend with a moderate correlation. A correlation between coercive force and the MBN RMS values was observed only for samples with abundant magnetite (&gt; 25 vol%). Conclusions: An increasing variation of the RMS values of the MBN signals was observed in relation with coercive force for abundant magnetite samples. This may be related to the geological processes involved in magnetite genesis. Method: The measurements were made exciting magnetically the samples (cylindrical shapes), using a magnetic yoke and measuring the induced field inside the rock as a result of the excitation. For the detection, a sensor coil placed on the excited surface on one of the flat faces of each cylinder was used. The signals obtained from MBN were digitized. A digital 5-200 kHz Butterworth filter was applied and the RMS (Root Mean Square) values were calculated. Results: The linear fit of the MBN RMS values with the increasing percentage of ferromagnetic minerals showed an increasing trend with moderate correlation. A correlation between coercive force and MBN RMS was observed only for samples with abundant magnetite (&gt; 25 vol%). Conclusions: A variation of the RMS values of the MBN signals was observed in relation with coercive force for massive magnetite samples. This can be related to geological processes involved in magnetite genesis. Keywords: Rocks, Magnetization, Barkhausen Magnetic Noise, Non-Destructive Test.

Machine Learning Applied to a Modern‐Pleistocene Petrographic Data Set: The Global Prediction of Sand Modal Composition (GloPrSM) Model

AbstractPetrography has long been used as a tool to decipher the sedimentary provenance of sand and sandstone based on relative proportions of detrital grain types. However, there is not yet a predictive framework that constrains the relationship between sand grain composition and the factors that influence it, including bedrock lithology, elevation, slope, basin area, precipitation, and temperature. We used a globally extensive modal point‐count data set of 3,522 Pleistocene to modern sand samples to train an inline series of random forest meta‐estimators to predict relative abundances of quartz (Q), feldspar (F), and lithic (L) grain types and eight subcompositions. The trained random forest models were fit to a global data set of fluvial watersheds to produce the global prediction of sand modal composition (GloPrSM) model which predicts Q‐F‐L of fluvially transported sediment. GloPrSM predicts quartz enrichment in low latitudes (35°N to 35°S), feldspar enrichment near plutonic and metamorphic crystalline terranes in middle to high latitudes, and lithic enrichment near modern and ancient collisional plate boundaries and flood basalts. Our analyses reveal that slope, temperature, and the relative abundance of exposed metamorphic and felsic to intermediate plutonic rocks are the most important predictors of Q‐F‐L composition. In addition, temperatures higher than 15°C and large drainage areas appear to promote quartz enrichment, while steeply sloping environments favor lithic enrichment. The GloPrSM model represents the first global‐scale estimate of fluvial sand compositional modes and illustrates that the spatial distribution of Q‐F‐L at Earth's surface can be predicted from the first‐order factors that generate sediment.

Petrography and tectonic provenance of the Permian Tunas Formation: Implications on the paleotectonic setting during the Claromecó Foreland Basin evolution, southwestern Gondwana margin, Argentina

The Claromecó Basin is located at the south-western sector of the Buenos Aires province, Argentina. This basin is considered a foreland basin closely related to the evolution of the southwestern Gondwana margin. This contribution focuses on the provenance analysis of the Tunas Formation (Permian, Pillahuincó Group), which represents the last filling stage for the Claromecó Foreland Basin. Petrographic and tectonic provenance analyses were performed in sandstones recovered from subsurface (PANG 0001 and PANG 0003 exploration wells) and outcrops located close to the basin center (Gonzales Chaves locality). In the subsurface, the analyzed succession is composed of medium- to fine-grained sandstones interbedded with tuffs, mudrocks, carbonaceous mudrocks and coal beds. In outcrops, the succession is dominated by medium-to fine-grained sandstones interbedded with siltstones. Modal composition patterns are distributed into the recycled orogen and transitionally recycled to mixed fields. Petrographic analyses, in addition to provenance and sedimentological studies, confirm that sedimentary material was derived from a mixed source, which largely comes from the Sierras Australes fold and thrust belt, located towards the W–SW, where the sedimentary succession is interbedded with volcanic material. The Tunas Formation shows clear differences in its modal composition, paleocurrent direction and paleoenvironmental conditions with respect to the underlying units of the Pillahuincó Group (Sauce Grande, Piedra Azul and Bonete formations). Source areas changed from cratonic to mixed fold belt/arc-derived material, suggesting variations in the Claromecó Basin configuration during the Late Paleozoic. Changes in the paleotectonic scenario during the deposition of the Tunas Formation have been interpreted as a consequence of a compressive post-collisional deformation event, the product of adjustment, accommodation and translation of terrains towards the equator during the Permian–Triassic to form Pangea.

Health economics-based verification of functional myocardial ischemia evaluation of stable coronary artery disease in Japan: A long-term longitudinal study using propensity score matching

BackgroundThe procedural numbers and medical costs of percutaneous coronary intervention (PCI), mainly elective PCI, have been increasing in Japan. Owing to increased interest in the appropriateness of coronary revascularization, we conducted this medical economics-based evaluation of testing and diagnosis of stable coronary artery disease (CAD). Methods and ResultsWe reviewed patients’ medical insurance data to identify stable CAD patients who underwent coronary computed tomography angiography, cardiac single-photon emission computed tomography, coronary angiography, or fractional flow reserve. Subjects were divided into anatomical and functional evaluation groups according to the modality of testing, and background factors were matched by propensity score. The endpoints were major adverse cardiovascular events (MACE), life years (LYs), medical costs, and cost-effectiveness analysis (CEA). The observations were performed for 36 months. MACE, medical costs, and CEA of the functional group in the overall category were trending to be better than the anatomical group (MACE, P = .051; medical costs: 3,105 US$ vs 4,430 US$, P = .007; CEA: 2,431 US$/LY vs 2,902 US$/LY, P = .043). ConclusionsThe functional evaluation approach improved long-term clinical outcomes and reduced cumulative medical costs. As a result, the modality composition of functional myocardial ischemia evaluation was demonstrated to offer superior cost-effectiveness in stable CAD.