Articles de revues : « Yield Curve Inversion »

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Ackermann, Hans D., Leroy W. Pankratz et Danny Dansereau. « Resolution of ambiguities of seismic refraction traveltime curves ». GEOPHYSICS 51, n^o 2 (février 1986) : 223–35. http://dx.doi.org/10.1190/1.1442082.

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Ambiguities are inherent in seismic refraction traveltime curves based on first arrivals recorded from a multi‐layered medium. Even for reversed profiles, inflections of traveltime curves caused by the onset of arrivals from successively deeper horizons frequently cannot be delineated from those caused by lateral geologic changes. In addition, the secondary arrivals which may represent essential portions of a traveltime curve are not available. Numerous inversions having different geologic implications are possible. Ambiguities may be resolved by using multiple shotpoints for each spread and combining their individual first‐arrival traveltime curves to yield a consistent set of curves for each refracting horizon. A set of rules applies for combining individual traveltime curves based on reversed, split, and offset profile configurations. The combined curves lend themselves to a unique inversion.

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Benenson, Olga. « Application of the Yield Curve Inversion Indicator to Determine the Current Phase of the Stock Market ». European Journal of Management Issues 30, n^o 4 (1 décembre 2022) : 235–42. http://dx.doi.org/10.15421/192221.

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Purpose: To establish the possibility of using the indicator of the inversion of the difference in the yield curve of 10-year and 2-year US Treasury bonds to determine the current phase of the stock market, predict the future direction of market movement and improve the efficiency of managerial investment decisions. Design/Method/Approach: The following methods were used when writing the paper: empirical – to carry out experimental checks of the revealed regularities; graphic - for a visual presentation of research results; systematization and generalization - for generalization of scientific concepts, developments, and proposals; statistical - to implement a quantitative approach to studying data. The US stock market was chosen as the base for research. The research was carried out by statistical processing of data on the value of the indicator of the inversion of the yield curve difference of 10-year and 2-year US Treasury bonds and the Standard & Poor's stock market index - 500 for the period from 1989 to 2022. Findings: It has been established that the indicator of the difference of the yield curve of 2-year and 10-year US Treasury bonds is a fairly reliable tool for determining the approaching recession in the economy, but at the same time it is not possible to determine the exact time of the recession. It is shown that this indicator is expedient to use for early warning about a possible fall in international stock markets. At the same time, it was found that not every inversion of the yield curve is followed by a fall in the stock market, but every fall is preceded by an inversion. It was noted that the current dynamics of the yield curve are signaling a possible significant drop in the US stock market in the near future. Theoretical Implications: Establishing the peculiarities of the indicator of the inversion of the yield curve difference of 10-year and 2-year US Treasury bonds in the conditions of the modern economy. Practical Implications: The practical application of the research results will allow us to more accurately determine the current phase of the international stock markets and receive early signals about the future decline of the markets, which will contribute to increasing investment efficiency. Originality/Value: This study expands knowledge about the peculiarities of the use of the indicator of the yield curve difference of 2-year and 10-year US Treasury bonds when determining the likely onset of a recession in the economy and the possibility of a fall in international stock markets, offers an updated model of the use of this indicator when forecasting the direction of movement of international stock markets. The results of the research may be of interest to specialists who work in the field of investing in international financial markets. Research Limitations/Future Research: The results of the work presented in this article create a basis for conducting similar research on the possibility of using other indicators in order to increase the accuracy of establishing the moment of recession in the economy or the beginning of a fall in international financial markets. From the author's point of view, first of all, such indicators as the movement of gold prices, the dynamics of changes in the Fed's discount rate, and Buffett’s indicator should be studied. This will make it possible to develop an effective application mechanism for making investment decisions and will contribute to increasing investment efficiency. Paper Type: Empirical JEL Classification: E44, F21, G15

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Habermann, M., M. Truffer et D. Maxwell. « Changing basal conditions during the speed-up of Jakobshavn Isbræ, Greenland ». Cryosphere Discussions 7, n^o 3 (1 juin 2013) : 2153–90. http://dx.doi.org/10.5194/tcd-7-2153-2013.

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Abstract. Ice-sheet outlet glaciers can undergo dynamic changes such as the rapid speed-up of Jakobshavn Isbræ following the disintegration of its floating ice tongue. These changes are associated with stress changes on the boundary of the ice mass. We investigate the basal conditions throughout a well-observed period of rapid change and evaluate parameterizations currently used in ice-sheet models. A Tikhonov inverse method with a Shallow Shelf Approximation forward model is used for diagnostic inversions for the years 1985, 2000, 2005, 2006 and 2008. Our ice softness, model norm, and regularization parameter choices are justified using the data-model misfit metric and the L-curve method. The sensitivity of the inversion results to these parameter choices is explored. We find a lowering of basal yield stress in the first 7 km of the 2008 grounding line and no significant changes higher upstream. The temporal evolution in the fast flow area is in broad agreement with a Mohr–Coulomb parameterization of basal shear stress, but with a till friction angle much lower than has been measured for till samples. The lowering of basal yield stress is significant within the uncertainties of the inversion, but it cannot be ruled out that there are other significant contributors to the acceleration of the glacier.

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Zou, Tianyuan, et Jing Zhang. « A New Fluorescence Quantum Yield Efficiency Retrieval Method to Simulate Chlorophyll Fluorescence under Natural Conditions ». Remote Sensing 12, n^o 24 (11 décembre 2020) : 4053. http://dx.doi.org/10.3390/rs12244053.

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Chlorophyll fluorescence (ChlF) is a useful indicator of plant photosynthesis and stress conditions. ChlF spectra can be simulated with the Fluspect model, which is a radiative transfer model that simulates leaf reflectance, transmittance, and fluorescence; however, it has never been used or validated under natural conditions. In this paper, a new fluorescence quantum yield efficiency of photosystem (FQE) retrieval method based on the Fluspect model is proposed for use in simulating ChlF in two healthy varieties of soybeans grown under natural conditions. The parameters, Chlorophyll a + b content (Cab), carotenoid (Cca), dry matter content (Cdm), indicator of leaf water content (Cw) and leaf mesophyll structure (N) and the simulated fluorescence from the experiment were compared with the measured values to validate the model under natural conditions. The results show a good correlation (coefficient of determination R2 = 0.7–0.9) with the measured data at wavelengths of 650–880 nm. However, there is a large relative error (RE) that extends up to 150% at the peak of the fluorescence curve. To improve the accuracy of the simulation, an inversion code containing the emission efficiency parameters for photosystems I and II was added, which retrieves FQE I and II from the measured fluorescence spectra. The evaluation results for all wavelengths and two peaks demonstrated a significant reduction in the error at the peak of the curve by the Fluspect model with the FQE inversion code. This new method reduced the overestimation of fluorescence from 150% to 20% for the RE, and the R2 value was higher than 0.9 at the spectra peaks. Additionally, the original plant parameter information remained mostly unchanged upon the addition of the inversion code.

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Capehart, T. W., et Y.-T. Cheng. « Determining constitutive models from conical indentation : Sensitivity analysis ». Journal of Materials Research 18, n^o 4 (avril 2003) : 827–32. http://dx.doi.org/10.1557/jmr.2003.0113.

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Several procedures have previously been advanced for extracting constitutive relations from the force–displacement curves obtained from indentation. This work addresses the specific problem of determining the elastic modulus E, yield stress Y, and hardening exponent n, which define the isotropic strain-hardening model from a single force–displacement curve with a sharp conical tip. The sensitivity of the inversion process was tested through a series of finite element calculations using ABAQUS. Different magnitudes of normally distributed noise were superimposed on a calculated force–displacement curve to simulate hypothetical data sets for specific values of E, Y, and n. The sensitivity of the parameter confidence intervals to noise was determined using the χ2-curvature matrix, statistical Monte Carlo simulations, and a conjugate gradient algorithm that explicitly searches the global parameter space. All three approaches demonstrate that 1% noise levels preclude the accurate determination of the strain-hardening parameters based on a single force–displacement curve.

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Habermann, M., M. Truffer et D. Maxwell. « Changing basal conditions during the speed-up of Jakobshavn Isbræ, Greenland ». Cryosphere 7, n^o 6 (7 novembre 2013) : 1679–92. http://dx.doi.org/10.5194/tc-7-1679-2013.

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Abstract. Ice-sheet outlet glaciers can undergo dynamic changes such as the rapid speed-up of Jakobshavn Isbræ following the disintegration of its floating ice tongue. These changes are associated with stress changes on the boundary of the ice mass. We invert for basal conditions from surface velocity data throughout a well-observed period of rapid change and evaluate parameterizations currently used in ice-sheet models. A Tikhonov inverse method with a shallow-shelf approximation forward model is used for diagnostic inversions for the years 1985, 2000, 2005, 2006 and 2008. Our ice-softness, model norm, and regularization parameter choices are justified using the data-model misfit metric and the L curve method. The sensitivity of the inversion results to these parameter choices is explored. We find a lowering of effective basal yield stress in the first 7 km upstream from the 2008 grounding line and no significant changes higher upstream. The temporal evolution in the fast flow area is in broad agreement with a Mohr–Coulomb parameterization of basal shear stress, but with a till friction angle much lower than has been measured for till samples. The lowering of effective basal yield stress is significant within the uncertainties of the inversion, but it cannot be ruled out that there are other significant contributors to the acceleration of the glacier.

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Korobov, Eugene, Yulia Semernina, Alina Usmanova et Kristina Odinokova. « Robotizing bond portfolio selection on the Russian debt market on the basis of a modified strategy of riding the yield curve ». Business Informatics 15, n^o 4 (31 décembre 2021) : 7–21. http://dx.doi.org/10.17323/2587-814x.2021.4.7.21.

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The modern global debt market features historically low average interest rates, convergence of yields on bonds with different maturities, an increase of yield curve inversion emergence frequency and a large-scale trend to automate financial decision making. The researchers’ attention in these fields is mainly focused on designing models that describe the state of the debt market as whole or its individual instruments in particular, as well as on risk management methods. At the same time, the specialized literature offers very few works concerning the topic of computer algorithms for bond portfolio selection based on traditional or advanced investment strategies. The aim of the present research is to create a modification of the existing algorithm of riding the yield curve strategy application, employing, first, average bond yield over the holding period instead of traditional bond yield to maturity; second, a developed algorithm for calculating the market spread on bonds; and, third, alternative risk evaluation indicators (compensation coefficients), which allow us to measure objectively price risk, liquidity risk, transaction costs risk and a general risk. The modification and the development of the algorithm for calculating the market spread were carried out using the direct measurement of the result technique, which entails application of the strategy to the data on bond issues received through the Moscow Exchange API. The selection of financial instruments was conducted in all sectors of the Russian debt market: public bonds, sub-federal and municipal bonds, corporate bonds. The modified algorithm enabled us to get extra yield for each selected bond issue, thereby proving the high effectiveness of the technique compared to the traditional strategy. Software implementation of the algorithm can be integrated into any robotized or semi-robotized stock exchange trading application.

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Wang, X. Henry, et Bill Z. Yang. « Yield Curve Inversion and the Incidence of Recession : A Dynamic IS-LM Model with Term Structure of Interest Rates ». International Advances in Economic Research 18, n^o 2 (16 février 2012) : 177–85. http://dx.doi.org/10.1007/s11294-012-9350-7.

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Muinonen, K., J. Torppa, X. B. Wang, A. Cellino et A. Penttilä. « Asteroid lightcurve inversion with Bayesian inference ». Astronomy & ; Astrophysics 642 (octobre 2020) : A138. http://dx.doi.org/10.1051/0004-6361/202038036.

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Context. We assess statistical inversion of asteroid rotation periods, pole orientations, shapes, and phase curve parameters from photometric lightcurve observations, here sparse data from the ESA Gaia space mission (Data Release 2) or dense and sparse data from ground-based observing programs. Aims. Assuming general convex shapes, we develop inverse methods for characterizing the Bayesian a posteriori probability density of the parameters (unknowns). We consider both random and systematic uncertainties (errors) in the observations, and assign weights to the observations with the help of Bayesian a priori probability densities. Methods. For general convex shapes comprising large numbers of parameters, we developed a Markov-chain Monte Carlo sampler (MCMC) with a novel proposal probability density function based on the simulation of virtual observations giving rise to virtual least-squares solutions. We utilized these least-squares solutions to construct a proposal probability density for MCMC sampling. For inverse methods involving triaxial ellipsoids, we update the uncertainty model for the observations. Results. We demonstrate the utilization of the inverse methods for three asteroids with Gaia photometry from Data Release 2: (21) Lutetia, (26) Proserpina, and (585) Bilkis. First, we validated the convex inverse methods using the combined ground-based and Gaia data for Lutetia, arriving at rotation and shape models in agreement with those derived with the help of Rosetta space mission data. Second, we applied the convex inverse methods to Proserpina and Bilkis, illustrating the potential of the Gaia photometry for setting constraints on asteroid light scattering as a function of the phase angle (the Sun-object-observer angle). Third, with the help of triaxial ellipsoid inversion as applied to Gaia photometry only, we provide additional proof that the absolute Gaia photometry alone can yield meaningful photometric slope parameters. Fourth, for (585) Bilkis, we report, with 1-σ uncertainties, a refined rotation period of (8.5750559 ± 0.0000026) h, pole longitude of 320.6° ± 1.2°, pole latitude of − 25.6° ± 1.7°, and the first shape model and its uncertainties from convex inversion. Conclusions. We conclude that the inverse methods provide realistic uncertainty estimators for the lightcurve inversion problem and that the Gaia photometry can provide an asteroid taxonomy based on the phase curves.

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Leng, Kuangdai, Stephen King, Tim Snow, Sarah Rogers, Anders Markvardsen, Satheesh Maheswaran et Jeyan Thiyagalingam. « Parameter inversion of a polydisperse system in small-angle scattering ». Journal of Applied Crystallography 55, n^o 4 (1 août 2022) : 966–77. http://dx.doi.org/10.1107/s1600576722006379.

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A general method to invert parameter distributions of a polydisperse system using data acquired from a small-angle scattering (SAS) experiment is presented. The forward problem, i.e. calculating the scattering intensity given the distributions of any causal parameters of a theoretical model, is generalized as a multi-linear map, characterized by a high-dimensional Green tensor that represents the complete scattering physics. The inverse problem, i.e. finding the maximum-likelihood estimation of the parameter distributions (in free form) given the scattering intensity (either a curve or an image) acquired from an experiment, is formulated as a constrained nonlinear programming (NLP) problem. This NLP problem is solved with high accuracy and efficiency via several theoretical and computational enhancements, such as an automatic data scaling for accuracy preservation and GPU acceleration for large-scale multi-parameter systems. Six numerical examples are presented, including both synthetic tests and solutions to real neutron and X-ray data sets, where the method is compared with several existing methods in terms of their generality, accuracy and computational cost. These examples show that SAS inversion is subject to a high degree of non-uniqueness of solution or structural ambiguity. With an ultra-high accuracy, the method can yield a series of near-optimal solutions that fit data to different acceptable levels.

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Chen, Jinbing. « Quasi-periodic solutions to a negative-order integrable system of 2-component KdV equation ». International Journal of Geometric Methods in Modern Physics 15, n^o 03 (20 février 2018) : 1850040. http://dx.doi.org/10.1142/s0219887818500408.

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In this paper, the backward and forward Neumann type systems are generalized to deduce the quasi-periodic solutions for a negative-order integrable system of 2-component KdV equation. The 2-component negative-order KdV (2-nKdV) equation is depicted as the zero-curvature representation of two spectral problems. It follows from a symmetric constraint that the 2-nKdV equation is reduced to a pair of backward and forward Neumann type systems, where the involutive solutions of Neumann type systems yield the finite parametric solutions of 2-nKdV equation. The negative-order Novikov equation is given to specify a finite-dimensional invariant subspace for the 2-nKdV flow. With a spectral curve given by the Lax matrix, the 2-nKdV flow is linearized on the Jacobi variety of a Riemann surface, which leads to the quasi-periodic solutions of 2-nKdV equation by using the Riemann-Jacobi inversion.

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Shen, Lanzhi, Maofang Gao, Jingwen Yan, Qizhi Wang et Hua Shen. « Winter Wheat SPAD Value Inversion Based on Multiple Pretreatment Methods ». Remote Sensing 14, n^o 18 (18 septembre 2022) : 4660. http://dx.doi.org/10.3390/rs14184660.

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SPAD value was measured by a portable chlorophyll instrument, which can reflect the relative chlorophyll content of vegetation well. Chlorophyll is an important organic chemical substance in plants that acquires and transmits energy during photosynthesis. The continuous spectral curve of winter wheat can be obtained rapidly in a specific band range by using hyperspectral remote sensing technology to estimate the SPAD value of winter wheat, which is of great significance to the growth monitoring and yield estimation research of winter wheat. In this study, with winter wheat as the research object, the spectral data and corresponding SPAD value in different growth stages were used as the data source, 20 kinds of data preprocessing spectra and sensitive spectral indices set the data as model input values, the partial least square regression (PLSR) model was established to estimate the SPAD value, and the model estimation results of different model input values at different growth stages were compared in detail. The results showed that the set of sensitive spectral indices selected in this study as input values can effectively improve the accuracy and stability of the PLSR model. In addition, the effects of 20 spectral data pretreatment methods on the estimation results of the SPAD value were compared and analyzed in different growth stages. It was found that the spectral data pretreated by the combination of wavelet packet denoising, first-order derivative transformation and principal component analysis can improve the accuracy and stability of PLSR model, and it is suitable for all growth stages. The results also showed that the estimation model is highly sensitive to the standard deviation of the SPAD value (STDchl) in sample sets. When the standard deviation is greater than 5.5 SPAD, the larger the STDchl is, the higher the model estimation accuracy is, and the more stable the model is. At this time, the model estimation accuracy is higher (R2V is greater than 0.5, ratio of performance to deviation is greater than 1.4), which can meet the estimation requirements of the SPAD value.

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Chen, Jinbing. « Quasi-periodic solutions of the negative-order Jaulent–Miodek hierarchy ». Reviews in Mathematical Physics 32, n^o 03 (29 août 2019) : 2050007. http://dx.doi.org/10.1142/s0129055x20500075.

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A uniform construction of quasi-periodic solutions to the negative-order Jaulent–Miodek (nJM) hierarchy is presented by using a family of backward Neumann type systems. From the backward Lenard gradients, the nJM hierarchy is put into the zero-curvature setting and the bi-Hamiltonian structure displaying its integrability. The nonlinearization of Lax pair is generalized to the nJM hierarchy such that it can be reduced to a sequence of backward Neumann type systems, whose involutive solutions yield finite parametric solutions of the nJM hierarchy. The negative [Formula: see text]-order stationary JM equation is given to specify a finite-dimensional invariant subspace for the nJM flows. With a spectral curve determined by the Lax matrix, the nJM flows are linearized on the Jacobi variety of a Riemann surface. Finally, the Riemann–Jacobi inversion is applied to Abel–Jacobi solutions of the nJM flows, by which some quasi-periodic solutions are obtained for the nJM hierarchy.

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Seylabi, Elnaz, Andrew M. Stuart et Domniki Asimaki. « Site Characterization at Downhole Arrays by Joint Inversion of Dispersion Data and Acceleration Time Series ». Bulletin of the Seismological Society of America 110, n^o 3 (5 mai 2020) : 1323–37. http://dx.doi.org/10.1785/0120190256.

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ABSTRACT We present a sequential data assimilation algorithm based on the ensemble Kalman inversion to estimate the near-surface shear-wave velocity profile and damping; this is applicable when heterogeneous data and a priori information that can be represented in forms of (physical) equality and inequality constraints in the inverse problem are available. Although noninvasive methods, such as surface-wave testing, are efficient and cost-effective methods for inferring an VS profile, one should acknowledge that site characterization using inverse analyses can yield erroneous results associated with the lack of inverse problem uniqueness. One viable solution to alleviate the unsuitability of the inverse problem is to enrich the prior knowledge and/or the data space with complementary observations. In the case of noninvasive methods, the pertinent data are the dispersion curve of surface waves, typically resolved by means of active source methods at high frequencies and passive methods at low frequencies. To improve the inverse problem suitability, horizontal-to-vertical spectral ratio data are commonly used jointly with the dispersion data in the inversion. In this article, we show that the joint inversion of dispersion and strong-motion downhole array data can also reduce the margins of uncertainty in the VS profile estimation. This is because acceleration time series recorded at downhole arrays include both body and surface waves and therefore can enrich the observational data space in the inverse problem setting. We also show how the proposed algorithm can be modified to systematically incorporate physical constraints that further enhance its suitability. We use both synthetic and real data to examine the performance of the proposed framework in estimation of the VS profile and damping at the Garner Valley downhole array and compare them against the VS estimations in previous studies.

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Zhang, Pingnan, Gang Chen, Jinning Wu, Chuanhai Wang, Shiwei Zheng, Yue Yu, Youlin Li et Xiaoning Li. « The Application and Improvement of Soil–Water Characteristic Curves through In Situ Monitoring Data in the Plains ». Water 14, n^o 24 (8 décembre 2022) : 4012. http://dx.doi.org/10.3390/w14244012.

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In order to study the soil–water characteristic curve and soil–water movement in the unsaturated zone of the humid plain area and investigate its influence on the regional water cycle process, this study conducted a long series of hydrometeorological data monitoring on the whole process of precipitation, evaporation, soil water content, pore water pressure and depth of groundwater level at the Jintan field hydrological test in the plain area of the Taihu Basin, China. Based on the collected data, the soil water dynamic at different depths was analyzed, and the results showed that the soil water fluctuated most frequently and drastically at a soil horizon depth of 0–40 cm, with an obvious soil moisture wetting and drying cycle. The van Genuchten model (VG model) was used to describe the soil–water characteristic curve, and the parameters of the VG model were obtained by numerical inversion of field monitoring data using numerical code (HYDRUS-1D). The obtained parameters were used to simulate soil water movement in each soil horizon for six precipitation events and were compared with the simulation results of laboratory data. The study shows that the soil water simulation based on field data is better, which verifies the accuracy and reliability of the VG model obtained from field observation and provides a reliable theoretical basis for soil water movement and the calculation of runoff yield in the plain area of the Taihu Basin.

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Bonadio, Raffaele, Sergei Lebedev, Thomas Meier, Pierre Arroucau, Andrew J. Schaeffer, Andrea Licciardi, Matthew R. Agius et al. « Optimal resolution tomography with error tracking and the structure of the crust and upper mantle beneath Ireland and Britain ». Geophysical Journal International 226, n^o 3 (23 avril 2021) : 2158–88. http://dx.doi.org/10.1093/gji/ggab169.

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SUMMARY The classical Backus–Gilbert method seeks localized Earth-structure averages at the shortest length scales possible, given a data set, data errors, and a threshold for acceptable model errors. The resolving length at a point is the width of the local averaging kernel, and the optimal averaging kernel is the narrowest one such that the model error is below a specified level. This approach is well suited for seismic tomography, which maps 3-D Earth structure using large sets of seismic measurements. The continual measurement-error decreases and data-redundancy increases have reduced the impact of random errors on tomographic models. Systematic errors, however, are resistant to data redundancy and their effect on the model is difficult to predict. Here, we develop a method for finding the optimal resolving length at every point, implementing it for surface-wave tomography. As in the Backus–Gilbert method, every solution at a point results from an entire-system inversion, and the model error is reduced by increasing the model-parameter averaging. The key advantage of our method stems from its direct, empirical evaluation of the posterior model error at a point. We first measure inter-station phase velocities at simultaneously recording station pairs and compute phase-velocity maps at densely, logarithmically spaced periods. Numerous versions of the maps with varying smoothness are then computed, ranging from very rough to very smooth. Phase-velocity curves extracted from the maps at every point can be inverted for shear-velocity (VS) profiles. As we show, errors in these phase-velocity curves increase nearly monotonically with the map roughness. We evaluate the error by isolating the roughness of the phase-velocity curve that cannot be explained by any Earth structure and determine the optimal resolving length at a point such that the error of the local phase-velocity curve is below a threshold. A 3-D VS model is then computed by the inversion of the composite phase-velocity maps with an optimal resolution at every point. The estimated optimal resolution shows smooth lateral variations, confirming the robustness of the procedure. Importantly, the optimal resolving length does not scale with the density of the data coverage: some of the best-sampled locations display relatively low lateral resolution, probably due to systematic errors in the data. We apply the method to image the lithosphere and underlying mantle beneath Ireland and Britain. Our very large data set was created using new data from Ireland Array, the Irish National Seismic Network, the UK Seismograph Network and other deployments. A total of 11 238 inter-station dispersion curves, spanning a very broad total period range (4–500 s), yield unprecedented data coverage of the area and provide fine regional resolution from the crust to the deep asthenosphere. The lateral resolution of the 3-D model is computed explicitly and varies from 39 km in central Ireland to over 800 km at the edges of the area, where the data coverage declines. Our tomography reveals pronounced, previously unknown variations in the lithospheric thickness beneath Ireland and Britain, with implications for their Caledonian assembly and for the mechanisms of the British Tertiary Igneous Province magmatism.

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Liotti, Giorgio, et Rosaria Rita Canale. « Trust in the European Union project and the role of ECB ». Economia Politica 38, n^o 2 (20 avril 2021) : 461–82. http://dx.doi.org/10.1007/s40888-021-00229-5.

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AbstractWas the European Central Bank able to assure the relaunch of the European project after the weakening of the post-crisis period? To answer this question, this paper presents an empirical analysis connecting citizen trust in the European Union with a variable intended to be a measure of the monetary policy strategy of the European Central Bank, namely, the interest rate on government bonds extracted from the 1-year maturity yield curve. The dynamic panel technique, applied to nineteen Eurozone countries for the time span of 2004–2018, estimates the presence of a long-run common relationship between the variables despite allowing different short-run adjustment mechanisms. Results are revealed to be not univocal: the easy monetary policy strategy is associated for the whole period with a decline of trust, and therefore, despite its impressiveness, it was not sufficient to relaunch the European Union project. However, when considering the change in strategy of the post-2013 period, it seemed to have contributed to a slight inversion of the decline of trust. These results highlight the importance of non-conventional measures and call for further support from coordinated policy action as a response to the negative shock deriving from the COVID-19 pandemic.

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von Frese, R. R. B., D. N. Ravat, W. J. Hinze et C. A. McGue. « Improved inversion of geopotential field anomalies for lithospheric investigations ». GEOPHYSICS 53, n^o 3 (mars 1988) : 375–85. http://dx.doi.org/10.1190/1.1442471.

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Instabilities and the large matrices which are common to inversions of regional magnetic and gravity anomalies often complicate the use of efficient least‐squares matrix procedures. Inversion stability profoundly affects anomaly analysis, and hence it must be considered in any application. Wildly varying or unstable solutions are the products of errors in the anomaly observations and the integrated effects of observation spacing, source spacing, elevation differences between sources and observations, geographic coordinate attributes, geomagnetic field attitudes, and other factors which influence the conditioning of inversion. Solution instabilities caused by ill‐posed parameters can be efficiently minimized by ridge regression with a damping factor large enough to stabilize the inversion, but small enough to produce an analytically useful solution. An effective choice for the damping factor is facilitated by plotting damping factors against residuals between observed and modeled anomalies and by then comparing this curve to curves of damping factors plotted against solution variance or the residuals between predicted anomaly maps representing the processing objective (e.g., downward continuation, differential reduction to the radial pole, etc.). To obtain accurate and efficient large‐scale inversions of anomaly data, a procedure based on the superposition principle of potential fields may be used. This method involves successive inversions of residuals between the observations and various stable model fields which can be readily accommodated by available computer memory. Integration of the model fields yields a well‐resolved representation of the observed anomalies corresponding to an integrated model which normally could not be obtained by direct inversion because the memory requirements would be excessive. MAGSAT magnetic anomaly inversions over India demonstrate the utility of these procedures for improving the geologic analysis of potential field anomalies.

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Pertuz-Comas, Alberto David, Octavio Andrés González-Estrada, Elkin Martínez-Díaz, Diego Fernando Villegas-Bermúdez et Jorge Guillermo Díaz-Rodríguez. « Strain-Based Fatigue Experimental Study on Ti–6Al–4V Alloy Manufactured by Electron Beam Melting ». Journal of Manufacturing and Materials Processing 7, n^o 1 (18 janvier 2023) : 25. http://dx.doi.org/10.3390/jmmp7010025.

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Additive manufacturing (AM) by electron beam melting (EBM) is a technique used to manufacture parts by melting powder metal layer-by-layer with an electron beam in a high vacuum, thereby generating a 3D topology. This paper studies the low-cycle fatigue of Ti–6Al–4V specimens obtained by EBM. Static tests were carried out according to ASTM E8 for a yield stress of 1023 MPa, a fracture stress of 1102 MPa, and a maximum tensile strength of 1130 MPa with a maximum true normal strain at fracture εmax = 9.0% and an elastic modulus of 120 GPa. Then, fatigue tests were conducted at a load inversion rate of R = −1. It was observed that the material exhibited plastic strain softening, which was attributed to the Bauschinger effect. These results were plotted on a strain vs. life (ε−N) curve using the Ong version of the Coffin–Manson rule and the Baumel–Seager and Meggiolaro–Castro rules. The results were compared to forged Ti–6Al–4V alloys. The cyclic stress–strain behavior was described with the Ramberg–Osgood model. Finally, the fracture surface was analyzed using scanning electron microscopy (SEM) to observe the formation of primary cracks. The fracture morphology showed a mixed surface, also known as a “quasi-cleavage”, which is characterized by dimples, cleavage facets, extensive primary cracks with broken slipping planes, and a large number of inclusions. This phenomenon caused a possible brittle behavior in the material.

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Cibulková, H., H. Nortunen, J. Ďurech, M. Kaasalainen, P. Vereš, R. Jedicke, R. J. Wainscoat et al. « Distribution of shape elongations of main belt asteroids derived from Pan-STARRS1 photometry ». Astronomy & ; Astrophysics 611 (mars 2018) : A86. http://dx.doi.org/10.1051/0004-6361/201731554.

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Context. A considerable amount of photometric data is produced by surveys such as Pan-STARRS, LONEOS, WISE, or Catalina. These data are a rich source of information about the physical properties of asteroids. There are several possible approaches for using these data. Light curve inversion is a typical method that works with individual asteroids. Our approach in focusing on large groups of asteroids, such as dynamical families and taxonomic classes, is statistical; the data are not sufficient for individual models.Aim. Our aim is to study the distributions of shape elongation b∕a and the spin axis latitude β for various subpopulations of asteroids and to compare our results, based on Pan-STARRS1 survey, with statistics previously carried out using various photometric databases, such as Lowell and WISE.Methods. We used the LEADER algorithm to compare the b∕a and β distributions for various subpopulations of asteroids. The algorithm creates a cumulative distributive function (CDF) of observed brightness variations, and computes the b∕a and β distributions with analytical basis functions that yield the observed CDF. A variant of LEADER is used to solve the joint distributions for synthetic populations to test the validity of the method.Results. When comparing distributions of shape elongation for groups of asteroids with different diameters D, we found that there are no differences for D < 25 km. We also constructed distributions for asteroids with different rotation periods and revealed that the fastest rotators with P = 0 − 4 h are more spheroidal than the population with P = 4−8 h.

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Payne, Michael A. « Looking ahead with vertical seismic profiles ». GEOPHYSICS 59, n^o 8 (août 1994) : 1182–91. http://dx.doi.org/10.1190/1.1443676.

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Several operations enhance our ability to predict the subsurface below the bottom total depth (TD) of the well when applied to zero‐offset vertical seismic profiling (VSP) data. Other key issues regarding the use of VSP data in this fashion are resolution and look‐ahead distance. An impedance log is the most useful form for presenting VSP data to look ahead of the drill bit. The VSP composite trace must first tie reliably to the surface seismic section and to the well log synthetic seismogram. The impedance log is obtained by inverting this VSP composite trace. However, before performing the inversion, we need to (1) correct the composite trace for attenuation effects below TD and (2) input velocities to provide low‐frequency information. An exponential gain function applied to the VSP data below TD adequately compensates for the loss of amplitude caused by attenuation. A calibration of the seismically derived velocities with VSP velocities yields the necessary low‐frequency information. These concepts are illustrated using a field data set and its subset truncated above TD. The output of these operations on the VSP data are compared to well log data. The question of resolution with these data was determined with a model VSP data set based on the well log data. The investigations indicate that the resolution attainable from look‐ahead data is on the order of 50–75 ft (15–23 m). This is one‐quarter seismic wavelength for the frequencies present in these data. In addition, the maximum look‐ahead distance for these data is shown to be easily 2000 ft (600) m and, perhaps, 4000 ft (1200 m5). By way of illustration, the techniques described and investigated 6were applied to an offshore VSP data set to yield an impedance log. After calibrating this curve with the well log data, the base of the target sand was correctly identified below TD. This prediction successfully yielded the thickness of the sand. Individual zones within the sand unit were identified with less confidence.

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Bolarín, M. C., F. G. Fernández, V. Cruz et J. Cuartero. « Salinity Tolerance in Four Wild Tomato Species using Vegetative Yield-Salinity Response Curves ». Journal of the American Society for Horticultural Science 116, n^o 2 (mars 1991) : 286–90. http://dx.doi.org/10.21273/jashs.116.2.286.

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The salinity tolerances of 21 accessions belonging to four wild tomato species [Lycopersicon pimpinellifolium (Jusl.) Mill., L. peruvianum (Corr.) D'Arcy, L. hirsutum (L.) Mill., and L. pennellii Humb. Bonpl.) were evaluated using their vegetative yield-salinity response curves at the adult stage, determined by a piecewise-linear response model. The slope (yield decrease per unit salinity increase), salinity response threshold, maximum electrical conductivity without yield reduction (ECo), and salinity level for which yield would be zero (ECo) were determined by a nonlinear least-squares inversion method from curves based on the response of leaf and stem dry weights to substrate EC. The genotype PE-2 (L. pimpinellifolium) had the highest salt tolerance, followed by PE-45 (L. pennellii), PE-34, PE-43 (L. hirsutum), and PE-16 (L. peruvianum). The model also was tested replacing substrate salinity levels with leaf Cl- or Na+ concentrations. Concentrations of both ions for which vegetative yields were zero (Clo and Nao) were determined from the response curves. In general, the most tolerant genotypes were those with the highest Clo and Nao values, suggesting that the dominant salt-tolerance mechanism is ion accumulation, but there were cases in which salt tolerance was not related to Clo and Nao.

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Yuval et Douglas W. Oldenburg. « Computation of Cole‐Cole parameters from IP data ». GEOPHYSICS 62, n^o 2 (mars 1997) : 436–48. http://dx.doi.org/10.1190/1.1444154.

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We develop a process to estimate Cole‐Cole parameters from time‐domain induced polarization (IP) surveys carried out over a nonuniform earth. The recovery of parameters takes the following steps. We first divide the earth into rectangular cells and assume that the Cole‐Cole decay parameters [Formula: see text] and c constant in each cell. Apparent chargeability data measured at times [Formula: see text] after the cessation of the input current are inverted using a 2-D inversion algorithm to recover the intrinsic chargeability structure [Formula: see text] for k = 1, L, where L is the number of time channels measured. When carrying out this inversion, it is necessary to introduce a normalization criterion so that the inversion outputs from the different time channels can be meshingfully combined. The L chargeability structures provide L estimates of the chargeability decay curve for each cell. The desired intrinsic Cole‐Cole parameters are recovered from these decay curves using a very fast simulated annealing (VFSA) algorithm. Application of the process in all cells provides interpretation maps of [Formula: see text], τ(x,z), and c(x, z). Our analysis is demonstrated on a synthetic example and is implemented on a field data set. The application of the process to field data yields reasonable results.

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BOUKRAA, S., J.-M. MAILLARD et G. ROLLET. « DETERMINANTAL IDENTITIES ON INTEGRABLE MAPPINGS ». International Journal of Modern Physics B 08, n^o 16 (20 juillet 1994) : 2157–201. http://dx.doi.org/10.1142/s0217979294000889.

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We describe birational representations of discrete groups generated by involutions, having their origin in the theory of exactly solvable vertex-models in lattice statistical mechanics. These involutions correspond respectively to two kinds of transformations on q×q matrices: the inversion of the q×q matrix and an (involutive) permutation of the entries of the matrix. In a case where the permutation is a particular elementary transposition of two entries, it is shown that the iteration of this group of birational transformations yield algebraic elliptic curves in the parameter space associated with the (homogeneous) entries of the matrix. It is also shown that the successive iterated matrices do have remarkable factorization properties which yield introducing a series of canonical polynomials corresponding to the greatest common factor in the entries. These polynomials do satisfy a simple nonlinear recurrence which also yields algebraic elliptic curves, associated with biquadratic relations. In fact, these polynomials not only satisfy one recurrence but a whole hierarchy of recurrences. Remarkably these recurrences are universal: they are independent of q, the size of the matrices. This study provides examples of infinite dimensional integrable mappings.

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Gao, Hongsi, Xiaochun Zhang, Xiugui Wang et Yuhong Zeng. « Phenology-Based Remote Sensing Assessment of Crop Water Productivity ». Water 15, n^o 2 (12 janvier 2023) : 329. http://dx.doi.org/10.3390/w15020329.

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The assessment of crop water productivity (CWP) is of practical significance for improving regional agricultural water use efficiency and water conservation levels. The remote sensing method is a common method for estimating large scale CWP, and the assessment errors in CWP by remote sensing originate mainly from remote sensing inversion errors in crop yield and evapotranspiration (ET). The phenological period is the important factor in crop ET and yield estimation. The crop coefficient (Kc) and harvest index (HI), which are closely related to different phenological periods, are considered during the processes of crop ET and yield estimation. The crop phenological period is detected from enhanced vegetation index (EVI) curves using Moderate Resolution Imaging Spectroradiometer (MODIS) data and Sentinel-2 data. The crop ET is estimated using the surface–energy balance algorithm for land (SEBAL) model and Penman‒Monteith (P-M) equation, and the crop yield is estimated using the dry matter mass–harvest index method. The CWP is calculated as the ratio of the crop yield to ET during the growing season. The results show that the daily ET and crop yield estimated from remote sensing images are consistent with the measured values. It is found from the variation in daily ET that the peaks appear at the heading period of wheat and maize, which are in good agreement with the rainfall and growth characteristics of the crop. The relationship between crop yield and ET shows a negative parabolic correlation, and that between CWP and crop yield shows a linear correlation. The average CWPs of wheat and maize are 1.60 kg/m3 and 1.39 kg/m3, respectively. The results indicate that the phenology-based remote sensing inversion method has a good effect on the assessment of CWP in Lixin County.

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Mallonn, M., E. Herrero, I. G. Juvan, C. von Essen, A. Rosich, I. Ribas, T. Granzer, X. Alexoudi et K. G. Strassmeier. « GJ 1214 : Rotation period, starspots, and uncertainty on the optical slope of the transmission spectrum ». Astronomy & ; Astrophysics 614 (juin 2018) : A35. http://dx.doi.org/10.1051/0004-6361/201732300.

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Aims. Brightness inhomogeneities in the stellar photosphere (dark spots or bright regions) affect the measurements of the planetary transmission spectrum. To investigate the star spots of the M dwarf GJ 1214, we conducted a multicolor photometric monitoring from 2012 to 2016. Methods. The time-series photometry was analyzed with the light curve inversion tool StarSim. Using the derived stellar surface properties from the light curve inversion, we modeled the impact of the star spots when unocculted by the transiting planet. We compared the photometric variability of GJ 1214 to published results of mid- to late M dwarfs from the MEarth sample. Results. The measured variability shows a periodicity of 125 ± 5 days, which we interpret as the signature of the stellar rotation period. This value overrules previous suggestions of a significantly shorter stellar rotation period. A light curve inversion of the monitoring data yields an estimation of the flux dimming of a permanent spot filling factor not contributing to the photometric variability, a temperature contrast of the spots of ~370 K and persistent active longitudes. The derived surface maps over all five seasons were used to estimate the influence of the star spots on the transmission spectrum of the planet from 400 to 2000 nm. The monitoring data presented here do not support a recent interpretation of a measured transmission spectrum of GJ 1214b as to be caused by bright regions in the stellar photosphere. Instead, we list arguments as to why the effect of dark spots likely dominated over bright regions in the period of our monitoring. Furthermore, our photometry proves an increase in variability over at least four years, indicative for a cyclic activity behavior. The age of GJ 1214 is likely between 6 and 10 Gyr. Conclusions. The long-term photometry allows for a correction of unocculted spots. For an active star such as GJ 1214, there remains a degeneracy between occulted spots and the transit parameters used to build the transmission spectrum. This degeneracy can only be broken by high-precision transit photometry resolving the spot crossing signature in the transit light curve.

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Thorson, Jeffrey R., et Jon F. Claerbout. « Velocity‐stack and slant‐stack stochastic inversion ». GEOPHYSICS 50, n^o 12 (décembre 1985) : 2727–41. http://dx.doi.org/10.1190/1.1441893.

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Normal moveout (NMO) and stacking, an important step in analysis of reflection seismic data, involves summation of seismic data over paths represented by a family of hyperbolic curves. This summation process is a linear transformation and maps the data into what might be called a velocity space: a two‐dimensional set of points indexed by time and velocity. Examination of data in velocity space is used for analysis of subsurface velocities and filtering of undesired coherent events (e.g., multiples), but the filtering step is useful only if an approximate inverse to the NMO and stack operation is available. One way to effect velocity filtering is to use the operator [Formula: see text] (defined as NMO and stacking) and its adjoint L as a transform pair, but this leads to unacceptable filtered output. Designing a better estimated inverse to L than [Formula: see text] is a generalization of the inversion problem of computerized tomography: deconvolving out the point‐spread function after back projection. The inversion process is complicated by missing data, because surface seismic data are recorded only within a finite spatial aperture on the Earth’s surface. Our approach to solving the problem of an ill‐conditioned or nonunique inverse [Formula: see text], brought on by missing data, is to design a stochastic inverse to L. Starting from a maximum a posteriori (MAP) estimator, a system of equations can be set up in which a priori information is incorporated into a sparseness measure: the output of the stochastic inverse is forced to be locally focused, in order to obtain the best possible resolution in velocity space. The size of the resulting nonlinear system of equations is immense, but using a few iterations with a gradient descent algorithm is adequate to obtain a reasonable solution. This theory may also be applied to other large, sparse linear operators. The stochastic inverse of the slant‐stack operator (a particular form of the Radon transform), can be developed in a parallel manner, and will yield an accurate slant‐stack inverse pair.

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Dou, Shan, et Jonathan B. Ajo-Franklin. « Full-wavefield inversion of surface waves for mapping embedded low-velocity zones in permafrost ». GEOPHYSICS 79, n^o 6 (1 novembre 2014) : EN107—EN124. http://dx.doi.org/10.1190/geo2013-0427.1.

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Surface waves are advantageous for mapping seismic structures of permafrost, in which irregular velocity gradients are common and thus the effectiveness of refraction methods are limited. Nevertheless, the complex velocity structures that are common in permafrost environments often yield unusual dispersion spectra, in which higher-order and leaky modes are dominant. Such unusual dispersion spectra were prevalent in the multichannel surface-wave data acquired from our permafrost study site at Barrow, Alaska. Owing to the difficulties in picking and identifying dispersion curves from these dispersion spectra, conventional surface-wave inversion methods become problematic to apply. To overcome these difficulties, we adopted a full-wavefield method to invert for velocity models that can best fit the dispersion spectra instead of the dispersion curves. The inferred velocity models were consistent with collocated electric resistivity results and with subsequent confirmation cores, which indicated the reliability of the recovered seismic structures. The results revealed embedded low-velocity zones underlying the ice-rich permafrost at our study site — an unexpected feature considering the low ground temperatures of [Formula: see text] to [Formula: see text]. The low velocities in these zones ([Formula: see text] lower than the overlying ice-rich permafrost) were most likely caused by saline pore-waters that prevent the ground from freezing, and the resultant velocity structures are vivid examples of complex subsurface properties in permafrost terrain. We determined that full-wavefield inversion of surface waves, although carrying higher computational costs than conventional methods, can be an effective tool for delineating the seismic structures of permafrost.

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Sahu, Kriti Ranjan, et Udayan De. « Dielectric Properties of PbNb2O6 up to 700°C from Impedance Spectroscopy ». Journal of Materials 2013 (8 mai 2013) : 1–15. http://dx.doi.org/10.1155/2013/702946.

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Piezoelectric materials have wide band gap and no inversion symmetry. Only the orthorhombic phase of lead metaniobate (PbNb2O6) can be ferroelectric and piezoelectric below Curie temperature, but not the rhombohedral phase. High temperature piezoelectric applications in current decades have revived international interest in orthorhombic PbNb2O6, synthesis of which in pure form is difficult and not well documented. Second problem is that its impedance spectroscopy (IS) data analysis is still incomplete. Present work attempts to fill up these two gaps. Presently found synthesis parameters yield purely orthorhombic PbNb2O6, as checked by X-ray Rietveld analysis and TEM. Present 20 Hz to 5.5 MHz IS from room temperature to 700°C shows its ferroelectric Curie temperature to be one of the highest reported, >574°C for 0.5 kHz and >580°C for 5.5 MHz. Dielectric characteristics and electrical properties (like capacitance, resistance and relaxation time of the equivalent CR circuit, AC and DC conductivities, and related activation energies), as derived here from a complete analysis of the IS data, are more extensive than what has yet been reported in the literature. All the properties show sharp changes across the Curie temperature. The temperature dependence of activation energies corresponding to AC and DC conductivities has been reexamined.

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Grechka, Vladimir, Andres Pech et Ilya Tsvankin. « Multicomponent stacking‐velocity tomography for transversely isotropic media ». GEOPHYSICS 67, n^o 5 (septembre 2002) : 1564–74. http://dx.doi.org/10.1190/1.1512802.

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Accurate estimation of the velocity field is the most difficult step in imaging of seismic data for anisotropic media. Here, the velocity‐analysis problem is examined for the most common anisotropic model of sedimentary formations—transverse isotropy (TI) with arbitrary orientation of the symmetry axis. We show that supplementing wide‐azimuth reflected PP data with mode‐converted (PS) waves yields more stable estimates of the anisotropic coefficients and, in many cases, helps to constrain the model in depth. An important processing step preceding the inversion is computation of the traveltimes of the pure SS‐waves from those of the PP‐, and PS‐waves based on a technique recently developed by Grechka and Tsvankin. This procedure allows us to replace PS‐wave moveout, which is generally asymmetric with respect to zero offset, with the symmetric (hyperbolic on short spreads) moveout of the pure SS reflections. Then, generalizing the algorithm previously suggested for PP data, we develop a joint tomographic inversion of the normal‐moveout (NMO) ellipses and zero‐offset traveltimes of PP‐ and SS‐waves. Application of the method to wide‐azimuth PP and PS reflections from a dipping interface beneath a homogeneous TI layer shows that for a range of reflector dips and tilt angles of the symmetry axis, it is possible to build the anisotropic velocity field in the depth domain. We also extend our inversion procedure to layered TI media with curved interfaces and study its stability in the presence of noise and heterogeneity.

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Sajeva, Angelo, Mattia Aleardi, Eusebio Stucchi, Nicola Bienati et Alfredo Mazzotti. « Estimation of acoustic macro models using a genetic full-waveform inversion : Applications to the Marmousi model ». GEOPHYSICS 81, n^o 4 (juillet 2016) : R173—R184. http://dx.doi.org/10.1190/geo2015-0198.1.

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We have developed a stochastic full-waveform inversion that uses genetic algorithms (GA FWI) to estimate acoustic macro models of the P-wave velocity field. Stochastic methods such as GA severely suffer the curse of dimensionality, meaning that they require unaffordable computer resources for inverse problems with many unknowns and expensive forward modeling. To mitigate this issue, we have proposed a two-grid technique with a coarse grid to represent the subsurface for the GA inversion and a finer grid for the forward modeling. We have applied this procedure to invert synthetic acoustic data of the Marmousi model, and we have developed three different tests. The first two tests use a velocity model derived from standard stacking velocity analysis as prior information and differ only for the parameterization of the coarse grid. Their comparison indicates that a smart parameterization of the coarse grid may significantly improve the final result. The third test uses a linearly increasing 1D velocity model as prior information, a layer-stripping procedure, and a large number of model evaluations. All three tests return velocity models that fairly reproduce the long-wavelength structures of the Marmousi. First-break cycle skipping related to the seismograms of the final GA-FWI models is significantly reduced compared with that computed on the models used as prior information. Descent-based FWIs starting from final GA-FWI models yield velocity models with low and comparable model misfits and with an improved reconstruction of the structural details. The quality of the models obtained by GA FWI plus descent-based FWI is benchmarked against the models obtained by descent-based FWI started from a smoothed version of the Marmousi and started directly from the prior information models. Our results are promising and demonstrate the ability of the two-grid GA FWI to yield velocity models suitable as input to descent-based FWI.

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S. LAVRYKOV, S., et B. V. RAMARAO. « Characterization of refined papermaking pulps using hydrodynamic parameters from filtration analysis ». May 2015 14, n^o 5 (1 juin 2015) : 305–9. http://dx.doi.org/10.32964/tj14.5.305.

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It is often necessary to characterize papermaking pulps in order to determine the impact of refining or to predict their drainage properties. The newer methods for pulp quality analysis determine geometrical features of pulp fibers by microimaging techniques. However, features such as fiber length, coarsenes, and their distributions do not yield easily to estimation of their drainage or papermaking properties. In quantifying the impact of refining on fiber quality, it is useful to approach the rheology of pulps as an indicator of their behavior. We determined the hydrodynamic characteristics of a variety of refined pulps along with their permeability characteristics, i.e., the hydrodynamic specific surface area and the specific volume. Our method was to analyze the filtration/drainage curves and fit predictions from models with observed data. This inversion problem is usually complex and requires global minimization techniques. This paper presents data on bleached kraft hardwood pulps and mixtures with fines and how their surface areas and specific volumes change with composition. These data are further used to predict the behavior of the pulps in drainage situations using models of forming.

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HAN, Y. M., S. B. CHOI et H. J. CHOI. « PREISACH MODEL OF ER FLUIDS CONSIDERING TEMPERATURE VARIATIONS ». International Journal of Modern Physics B 19, n^o 07n09 (10 avril 2005) : 1325–31. http://dx.doi.org/10.1142/s0217979205030256.

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This paper presents a new approach for hysteresis modeling of an electro-rheological (ER) fluid. The Preisach model is adopted to describe change of an ER fluid hysteresis with temperature, and its applicability is experimentally proved by examining two significant properties under two dominant temperature conditions. As a first step, the polymethylaniline (PMA)-based ER fluid is made by dispersing the chemically synthesized PMA particles into non-conducting oil. Then, using the Couette type electroviscometer, multiple first order descending (FOD) curves are constructed to consider temperature variations in the model. Subsequently, a nonlinear hysteresis model of the ER fluid is formulated between input (electric field) and output (yield stress). A compensation strategy is also formulated in a discrete manner through the Preisach model inversion to attain desired shear stress of the ER fluid. In order to demonstrate the effectiveness of the identified hysteresis model and the tracking performance of the control strategy, the field-dependent hysteresis loop and tracking error responses are experimentally evaluated in time domain and compared with responses obtained from Bingham model.

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Wu, Jin, Douglas Cooper et Robert Miller. « Virtual Impactor Aerosol Concentrator for Cleanroom Monitoring ». Journal of the IEST 32, n^o 4 (1 juillet 1989) : 52–56. http://dx.doi.org/10.17764/jiet.1.32.4.j663114j2007072l.

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Particles equal to or larger than 1 μm in size can significantly reduce the yield in the microelectronics industry. This is particularly evident in the packaging stage of manufacturing when chips are inter-connected, because of the relatively large areas that must be kept contamination-free during this process. Monitoring is usually done with optical particle counters. The low particle concentrations in clean-rooms, however, result in low counts and high variability. This article presents a monitoring system that uses a virtual impactor to concentrate particles between 0.65 to 2.5 μm dia and counts them with a 0.3 L/min (lpm) particle counter. Theoretical concentration enhancement ratios versus particle size are given. The use of the virtual impactor in a clean environment is demonstrated. Tests show that the transition between the concentrated sizes is sharp. The dependence of the ratios versus particle size is in qualitative agreement with theory. An aerosol concentrator could be used to give more accurate micron-size particle concentrations through a data inversion process, if experimental calibration curves are provided.

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Nour El-Din, Hanzada T., Noha M. Elhosseiny, Mohamed A. El-Gendy, Azza A. Mahmoud, Manal M. M. Hussein et Ahmed S. Attia. « A Rapid Lysostaphin Production Approach and a Convenient Novel Lysostaphin Loaded Nano-emulgel ; As a Sustainable Low-Cost Methicillin-Resistant Staphylococcus aureus Combating Platform ». Biomolecules 10, n^o 3 (12 mars 2020) : 435. http://dx.doi.org/10.3390/biom10030435.

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Staphylococcus aureus is a Gram-positive pathogen that is capable of infecting almost every organ in the human body. Alarmingly, the rapid emergence of methicillin-resistant S. aureus strains (MRSA) jeopardizes the available treatment options. Herein, we propose sustainable, low-cost production of recombinant lysostaphin (rLST), which is a native bacteriocin destroying the staphylococcal cell wall through its endopeptidase activity. We combined the use of E. coli BL21(DE3)/pET15b, factorial design, and simple Ni-NTA affinity chromatography to optimize rLST production. The enzyme yield was up to 50 mg/L culture, surpassing reported systems. Our rLST demonstrated superlative biofilm combating ability by inhibiting staphylococcal biofilms formation and detachment of already formed biofilms, compared to vancomycin and linezolid. Furthermore, we aimed at developing a novel rLST topical formula targeting staphylococcal skin infections. The phase inversion composition (PIC) method fulfilled this aim with its simple preparatory steps and affordable components. LST nano-emulgel (LNEG) was able to extend active LST release up to 8 h and cure skin infections in a murine skin model. We are introducing a rapid, convenient rLST production platform with an outcome of pure, active rLST incorporated into an effective LNEG formula with scaling-up potential to satisfy the needs of both research and therapeutic purposes.

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Hördt, Andreas, Vladimir L. Druskin, Leonid A. Knizhnerman et Kurt‐Martin Strack. « Interpretation of 3-D effects in long‐offset transient electromagnetic (LOTEM) soundings in the Münsterland area/Germany ». GEOPHYSICS 57, n^o 9 (septembre 1992) : 1127–37. http://dx.doi.org/10.1190/1.1443327.

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The interpretation of long‐offset transient electromagnetic (LOTEM) data is usually based on layered earth models. Effects of lateral conductivity variations are commonly explained qualitatively, because three‐dimensional (3-D) numerical modeling is not readily available for complex geology. One of the first quantitative 3-D interpretations of LOTEM data is carried out using measurements from the Münsterland basin in northern Germany. In this survey area, four data sets show effects of lateral variations including a sign reversal in the measured voltage curve at one site. This sign reversal is a clear indicator of two‐dimensional (2-D) or 3-D conductivity structure, and can be caused by current channeling in a near‐surface conductive body. Our interpretation strategy involves three different 3-D forward modeling programs. A thin‐sheet integral equation modeling routine used with inversion gives a first guess about the location and strike of the anomaly. A volume integral equation program allows models that may be considered possible geological explanations for the conductivity anomaly. A new finite‐difference algorithm permits modeling of much more complex conductivity structures for simulating a realistic geological situation. The final model has the zone of anomalous conductivity aligned below a creek system at the surface. Since the creeks flow along weak zones in this area, the interpretation seems geologically reasonable. The interpreted model also yields a good fit to the data.

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Kim, Yongon, et Y. Richard Kim. « Prediction of Layer Moduli from Falling Weight Deflectometer and Surface Wave Measurements Using Artificial Neural Network ». Transportation Research Record : Journal of the Transportation Research Board 1639, n^o 1 (janvier 1998) : 53–61. http://dx.doi.org/10.3141/1639-06.

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A new algorithm for predicting layer moduli using measurements from both falling weight deflectometer (FWD) and surface wave tests is presented. This algorithm employs numerical solutions of a multilayered half-space based on Hankel transforms as a forward model and an artificial neural network (ANN) for the inversion process. Phase velocities for frequencies ranging from 10 Hz to 10,000 Hz are calculated using the forward model for varying pavement structures with a range of layer moduli and thicknesses. These phase velocities, along with the layer moduli and thicknesses, are used to train an ANN to backcalculate layer moduli from dispersion curves (i.e., phase velocity versus frequency curves) constructed from the FWD and stress wave test data. To account for the effect of bedrock on the moduli prediction, another network is trained with layer thicknesses and phase velocities for predicting the depth to bedrock. Combining this network with the network for the moduli prediction results in a sequential dispersion analysis technique in which the depth to bedrock predicted from the first network becomes an input to the second network for predicting layer moduli. FWD and stress wave test measurements from an intact pavement and an asphalt overlay over cracked asphalt layer are processed using the sequential dispersion analysis technique and MODULUS 5.0 backcalculation program. Comparison of the results indicates that the dispersion analysis technique yields less variable subgrade moduli and is more sensitive to changes in the asphalt surface layer, because the high-frequency data from the stress wave test is incorporated.

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Kurtz, R. D., et J. C. Gupta. « Shallow and deep crustal conductivity studies in the Miramichi earthquake zone, New Brunswick ». Canadian Journal of Earth Sciences 29, n^o 7 (1 juillet 1992) : 1549–64. http://dx.doi.org/10.1139/e92-122.

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The occurrence in early 1982 of four earthquakes in north-central New Brunswick with magnitudes ranging from 5.0 to 5.7 mb prompted detailed electromagnetic surveys of the epicentral region. Scalar audiomagnetotelluric (AMT) measurements, spaced at 100 m intervals or less, along a 7.5 km east–west profile located two conductors but did not find anomalies that could be associated with the proposed fault plane defined by the earthquake hypocentres.The 150 AMT measurements, combined with broad-band tensor soundings at 11 sites in a confined region (6 km × 7.5 km), provided an opportunity to study the distorting effects of near-surface anomalies and also to determine the regional conductivity structure. The apparent resistivity and phase curves from all tensor stations, calculated in a common coordinate system, were remarkably similar (except for static shift of the apparent resistivity curves) to those derived from the rotationally invariant Berdichevsky determinant averages. These averages appear to be very effective for deriving a first-order estimate of the conductivity structure in areas for which near-surface anomalies are a problem.A geometric mean of the AMT measurements was used to estimate the correct level for the high-frequency asymptotes of the tensor apparent resistivity curves. A one-dimensional inversion of the tensor magnetotelluric (MT) data, with the apparent resistivity shifted to the AMT average, yields a four-layer electrical conductivity model for the crust, with depths from the surface of 2.4, 19, and 32 km and with resistivities of 10 000, >100 000, 10 000, and 300 Ω∙m. The crustal resistivities in the Miramichi region are considerably larger than those in other regions in eastern North America but are typical for the Precambrian Shield. As well, there is an indication of lower crustal and (or) upper mantle electrical anisotropy. The geomagnetic transfer function data suggest the presence of a north-northwest-trending structure 7–12 km east of the Miramichi survey area. At present there is little other geophysical or geological evidence for this conductive anomaly.

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Hable, Sarah, Karin Sigloch, Eléonore Stutzmann, Sergey Kiselev et Guilhem Barruol. « Tomography of crust and lithosphere in the western Indian Ocean from noise cross-correlations of land and ocean bottom seismometers ». Geophysical Journal International 219, n^o 2 (26 juillet 2019) : 924–44. http://dx.doi.org/10.1093/gji/ggz333.

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SUMMARY We use seismic noise cross-correlations to obtain a 3-D tomography model of SV-wave velocities beneath the western Indian Ocean, in the depth range of the oceanic crust and uppermost mantle. The study area covers 2000 × 2000 km2 between Madagascar and the three spreading ridges of the Indian Ocean, centred on the volcanic hotspot of La Réunion. We use seismograms from 38 ocean bottom seismometers (OBSs) deployed by the RHUM-RUM project and 10 island stations on La Réunion, Madagascar, Mauritius, Rodrigues, and Tromelin. Phase cross-correlations are calculated for 1119 OBS-to-OBS, land-to-OBS, and land-to-land station pairs, and a phase-weighted stacking algorithm yields robust group velocity measurements in the period range of 3–50 s. We demonstrate that OBS correlations across large interstation distances of >2000 km are of sufficiently high quality for large-scale tomography of ocean basins. Many OBSs yielded similarly good group velocity measurements as land stations. Besides Rayleigh waves, the noise correlations contain a low-velocity wave type propagating at 0.8–1.5 km s−1 over distances exceeding 1000 km, presumably Scholte waves travelling through seafloor sediments. The 100 highest-quality group velocity curves are selected for tomographic inversion at crustal and lithospheric depths. The inversion is executed jointly with a data set of longer-period, Rayleigh-wave phase and group velocity measurements from earthquakes, which had previously yielded a 3-D model of Indian Ocean lithosphere and asthenosphere. Robust resolution tests and plausible structural findings in the upper 30 km validate the use of noise-derived OBS correlations for adding crustal structure to earthquake-derived tomography of the oceanic mantle. Relative to crustal reference model CRUST1.0, our new shear-velocity model tends to enhance both slow and fast anomalies. It reveals slow anomalies at 20 km depth beneath La Réunion, Mauritius, Rodrigues Ridge, Madagascar Rise, and beneath the Central Indian spreading ridge. These structures can clearly be associated with increased crustal thickness and/or volcanic activity. Locally thickened crust beneath La Réunion and Mauritius is probably related to magmatic underplating by the hotspot. In addition, these islands are characterized by a thickened lithosphere that may reflect the depleted, dehydrated mantle regions from which the crustal melts where sourced. Our tomography model is available as electronic supplement.

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Garcia, Emmanuel Soliman M., David T. Sandwell et Dan Bassett. « Outer trench slope flexure and faulting at Pacific basin subduction zones ». Geophysical Journal International 218, n^o 1 (27 mars 2019) : 708–28. http://dx.doi.org/10.1093/gji/ggz155.

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SUMMARY Flexure and fracturing of the seafloor on the outer trench wall of subduction zones reflect bending of the lithosphere beyond its elastic limit. To investigate these inelastic processes, we have developed a full nonlinear inversion approach for estimating the bending moment, curvature and outer trench wall fracturing using shipboard bathymetry and satellite altimetry-derived gravity data as constraints. Bending moments and downward forces are imposed along curved trench axes and an iterative method is used to calculate the nonlinear response for 26 sites in the circum-Pacific region having seafloor age ranging from 15 to 148 Ma. We use standard thermal and yield strength envelope models to develop the nonlinear moment versus curvature relationship. Two coefficients of friction of 0.6 and 0.3 are considered and we find that the lower value provides a better overall fit to the data. The main result is that the lithosphere is nearly moment saturated at the trench axis. The effective elastic thickness of the plate on the outer trench slope is at least three times smaller than the elastic thickness of the plate before bending at the outer rise in agreement with previous studies. The average seafloor depth of the unbent plate in these 26 sites matches the Parsons & Sclater depth versus age model beyond 120 Ma. We also use the model to predict the offsets of normal faults on the outer trench walls and compare this with the horst and graben structures observed by multibeam surveys. The model with the lower coefficient of friction fits the fault offset data close to the trench axis. However, the model predicts significant fracturing of the lithosphere between 75 and 150 km away from the trench axis where no fracturing is observed. To reconcile these observations, we impose a thermoelastic pre-stress in the lithosphere prior to subduction. This pre-stress delays the onset of fracturing in better agreement with the data.

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Rokityansky, I. I., et A. V. Tereshyn. « Donbas geoelectrical structure ». Geofizicheskiy Zhurnal 44, n^o 1 (3 avril 2022) : 158–72. http://dx.doi.org/10.24028/gzh.v44i1.253717.

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The Donbas was formed as the result of Late Devonian rifting of the East European craton. During the Carboniferous, the subsidence of the basin and sedimentation were at their maximum, and a 15-kilometer stratum of Carboniferous deposits formed in the Donbas. The total thickness of the deposits reaches more than 20 km. The next important event was folding, which occurred in the Late Triassic — Early Jurassic and Late Cretaceous — Early Tertiary. The inversion lifted the upper part of the folded Donbas and subsequent erosion exposed the Carboniferous coal-bearing strata on the surface of the earth. Deep electrical conductivity was studied by the methods of magnetovariational profiling (MVP) and magnetotelluric sounding (MTS). The first large survey (13 long-period MTS sites and 32 MTS points) was carried out in 1986; in 1988 another 30 MTS were performed. In 2012-2013, a profile of 15 MVP-MTS sites was made with modern instruments that allow obtaining more accurate results. The data interpretation yields the following conclusions. The intense Donbass electrical conductivity anomaly (DAE) runs along the main anticline of the folded Donbass. In the northwest, it continues in the DDD, in the southeast — on the Karpinsky swell. DAE parameters obtained by the MVP method: Based on the frequency response of the anomalous field, the total longitudinal conductance G = (8±2)×108S×m was estimated. Profile graphs of the anomalous field of geomagnetic variations give an estimate of the maximum possible depth of the anomalous currents center hmax.c.curr, which depends on the variations period. For DAE at the maximum frequency response Т0≈3600 s, it turns out to be equal to hmax.c.curr=18±2 km. The upper edge of the anomaly is estimated from MTS data. Most of the available 70 MTS ρк curves begin at periods of 0.1—1 s from approximately the same level of 15 Ohm·m±half an order of magnitude. This means that in the Donbass, the rocks of the upper approximately half-kilometer layer have, as a rule, electrical resistivity in the range of 5—50 Ohm·m. Deeper, the resistivity can increase to hundreds and thousands of Ohm·m or decrease to units or fractions of Ohm·m. An analysis of the MTS by area showed that objects of low resistance (LRO) are located in two conductive bands, the upper edge of which varies from 0.3 to 5 km. The bands are parallel to the DAE axis and can be considered as some part of the anomaly. A very large value of G leads to the assumption that the anomalous body extends to a considerable depth. When compared with the data of other geophysical methods, it turned out that the DAE spatially coincides with an intense (up to 90 mW/m2) linear anomaly of the deep heat flow. This fact suggests that the nature of the DAE lower part can be a partial melting of fluid-enriched heated local rocks or intrusion of mantle magma. The obtained geoelectric results support the idea of the modern tectonic activation in Donbas.

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Loflin, Benjamin, Kaitlyn Colglazier et Stephen Schlecht. « Poster 254 : Mechanical Response of ACL to Submaximal Fatigue Loading ». Orthopaedic Journal of Sports Medicine 10, n^o 7_suppl5 (1 juillet 2022) : 2325967121S0081. http://dx.doi.org/10.1177/2325967121s00815.

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Objectives: It has been previously reported that the ACL increases in size and strength throughout rodent adolescence following both voluntary1 and forced2 endurance running. Here, we expand upon these findings to investigate how the ACL responds to submaximal fatigue loading. The ACL of sexually mature mice was subjected to 3 days of in vivo repetitive loading with an intervening day for recovery. We hypothesized that direct repetitive loading would should a greater positive change in ACL mechanical properties than what was previously observed following endurance running. To test this hypothesis, we designed a custom loading fixture to apply repetitive ACL loading cycles up to a predetermined percentage of the ACL failure load while approximating the knee kinematics of a jump-landing with a pivot shift. Methods: With Institutional approval, 20 C57BL/6J 10-week-old female mice underwent ACL fatigue loading across 3 days with an intervening recovery day following each training session. For each loading session, the right rear leg of the mouse was placed in a custom loading fixture with the knee at 90° flexion and the sole of the foot at 20° inversion to induce a valgus moment across the knee (Fig. 1). Once positioned, the foreleg was internally rotated. Internal tibial rotation combined with a valgus moment across the knee generates maximum peak ACL strain and replicates a well characterized clinical ACL injury mechanism3. Based on our previous in vivo work we chose two ACL ultimate tensile strength (UTS) loading percentages that represent low and moderate loads to repetitively fatigue the ligament. An in vivo 60% ACL UTS reliably generates collagen triple helix degradation followed by a proteoglycan response (Fig. 2), while no such changes occur at an in vivo 30% ACL UTS. Therefore, for each training session the ACL was cyclically loaded in vivo between 30% and 60% of ACL UTS for 440 cycles at a loading rate of 0.75 mm/s. After the third session mice were allowed to recover for 72 hrs. Following this, the tested and age-matched control ACLs were ruptured in vivo using the same knee kinematics at a loading rate of 2.7 N/s. All ACLs failed interstitially with there being no visible damage to other supporting knee ligaments or menisci. The resulting load-displacement curves were analyzed using custom MatLab code to quantify the mechanical properties of the fatigued and non-fatigued ACLs. In vivo measures quantified included ACL UTS, stiffness (S), total yield strength (TYS) and post-yield displacement (PYD). Data were analyzed using a two-way ANOVA with final body weight included as a covariate in order to determine the mechanical effect that the 3 days of submaximal fatigue loading had on the ACL compared to controls. Results: The submaximal fatigue loading had a significant effect on ACL mechanical properties when compared to controls. Five mice suffered an ACL failure during the fatigue loading experiment, suggesting that 60% ACL UTS may be near the fatigue failure threshold in these mice. The remaining 15 mice that completed the fatigue study showed a 24.0% increase in UTS, a 26.8% increase in S, a 18.5% increase in TYS, and a 130.5% increase in post-yield displacement, compared to controls (Table 1). Conclusions: The outcomes of this study partially confirmed our hypothesis. Three days of direct repetitive loading elicited a greater ACL mechanical response than similar aged female mice following 4 weeks of endurance running. The marked improvement in ACL mechanics following repetitive training was likely due to the greater ACL loads experienced and the time allowed for tissue recovery. Rodent ligaments can turn collagen over in ˜24 hours4. This suggests that the accumulation of degenerated ACL collagen triple helix structures was repaired during recovery for 75% of the mice. However, it also suggests that for some mice, ACL collagen degeneration was not repaired but rather accumulated and propagated hierarchically to the fibril and fiber level, resulting in tissue failure, as was previously observed in human cadaver knees subjected to submaximal ACL fatigue loading5. This study further elucidates how the ACL responds to loading during adolescence. We have demonstrated that systematic repetitive ACL loading in adolescent mice can generate a positive mechanical response in the ACL. However, our findings also suggest that for a subset of mice participating in this training the submaximal fatigue load was too high and/or the duration of the recovery period was insufficient, resulting in catastrophic failure of the ligament prior to study completion. In the future, these failures should be able to be prevented by reducing the maximum load experienced by the ACL, increasing the duration of the recovery period, or both. If translatable to humans, these and future findings may assist clinicans in identifying potential risks for ACL injury related to an individual’s training intensity and help guide clinical inteventions. 1Schlecht et al., J Orthop Res, 2019; 2Cabaud et al., Am J Sports Med, 1980; 3Wojtys et al., J Orthop Res, 2016; 4Sodek, Arch Oral Biol, 1977; 5Chen et al., Am J Sports Med, 2019. [Figure: see text][Figure: see text][Table: see text]

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Lapinskas, Tomas, Chiodi Elisabetta, Chrysanthos Grigoratos, Ricardo Ladeiras-Lopes, GJ Fent, E. Abdul Rahman, Jonathan Rodrigues et al. « VIEWING ONLY POSTERS1323Evaluation of right ventricular transverse strain and strain rate in patients with acute ST-segment elevation myocardial infarction : a cardiac magnetic resonance feature tracking study1333Cardiac resynchronization in ischemic heart failure patients : a comparison between therapy guided by cardiac magnetic resonance imaging and 2D-speckle tracking echocardiography1338Cardiac magnetic resonance versus bisphosphonate scintigraphy for diagnosis of cardiac amyloidosis1341Strain relaxation index, a novel tagged MRI-derived diastolic function parameter, is impaired in metabolic syndrome1349Global Longitudinal Strain Predicts Chronic Myocardial Infarction in Patients with Normal Ejection Fraction1352Optimal Dose Of Dobutamine During Low-Dose Dobutamine Stress Echocardiography In Correctly Identify Viable Segments On Cardiovascular Magnetic Resonance1368Absolute wall thickening and left ventricular ejection fraction–a unifying theory of myocardial contraction and heart failure?1376Transient St Elevation in Acs Like Myocarditis1379Patients after Fontan with a “total cavopulmonary connection” Fontan modification develop more collateral flow compared to “old-fashioned” Fontan modifications1387A MRI–derived 3D patient specific model for fibrosis quantification in atrial fibrillation1391Scar burden and survival in patients with ischemic cardiomyopathy and poor LV ejection fraction1392Relation of inflammatory markers with myocardial and microvascular injury in patients with reperfused ST- elevation myocardial infarction1406Equivalence of segmented conventional and fast single-shot late gadolinium enhancement (LGE) techniques for1410Cardiac Mri Appearances of Tuberculosis - A Review of Varied Presentations in India1415Atheroma burden, cardiac remodelling and epicardial fat : A comparison between healthy South Asian and European adults using Whole Body Cardiovascular MR1418Symptomatic Ventricular Arrhythmias : Diagnostic Yield of Cardiac Magnetic Resonance1421CMR assessment of aortic stiffness in asymptomatic low risk patients with type 2 diabetes mellitus1436Shock index as a predictor of myocardial damage and clinical outcome in ST-elevation myocardial infarction1451Combined biomarker testing for the prediction of microvascular obstruction after primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction1452A novel oscillometric technique compared with cardiac magnetic resonance for the assessment of aortic pulse wave velocity in ST-segment elevation myocardial infarction1456Aorto-pulmonary collaterals evaluated by CMR is associated to reduced “effective” cardiac index late after Fontan palliation1458Evaluation of pulmonary transit time and Pulmonary Blood Volume with first-pass perfusion CMR imaging in adult with repaired Congenital Heart disease1459Prognostic value of the cardiac magnetic resonance as a predictor of improvement in ventricular function after TakoTsubo syndrome1462Diagnostic performance of ECG detection of left atrial enlargement in patients with arterial hypertension relative to the cardiac magnetic resonance gold-standard : impact of obesity1463Utility of cardiac magnetic resonance imaging for diagnosis of cardiac sarcoidosis and prediction of therapeutic effects in patients with complete heart block and implanted magnetic resonance-conditional pacemaker : A multicenter study1467Cardiac magnetic resonance late gadolinium enhancement in patients with genetic dilated cardiomyopathy14712.Left ventricular hypertrophy in hypertensive patients–comparison of Cardiac Magnetic Resonance and Echocardiographic analysis of morphological and functional LV-parameters1472Is Angiographic Perfusion Score assessed in patients with acute myocardial infarction correlated with Cardiac Magnetic Resonance infarct size and N-terminal pro-brain natriuretic peptide in 6-month follow-up1476Cardiac Magnetic Resonance Patterns of Left Ventricular Diastolic Function In Hypertrophic Cardiomyopathy1477Impact of platelet volume on thrombus burden and tissue reperfusion in patients with STEMI treated with primary angioplasty : MRI study1479Right ventricle systolic function assessment and its prognostic implications in cardiac amyloidosis1484Cardiac MRI - an important tool in the evaluation of multsystemic inflamatory diseases. An Erdheim-Chester Disease case report1485Predictive value of cardiac magnetic resonance for future adverse cardiac events in patients with ST-segment elevation myocardial infarction1486Time-to-treatment but not thrombectomy influence infarct size and microvascular obstruction in patients with acute ST-segment elevation myocardial infarction treated with primary coronary intervention1489Primary PCI versus Early Routine Post Fibrinolysis PCI for ST Elevation Myocardial Infarction1490Evaluation of ventricular function in Fontan patients undergoing feature tracking magnetic resonance strain1491Impacts of atrialized right ventricle and left ventricular displacement in Ebstein's anomaly on left ventricular function assessed by cardiovascular MRI1494Final diagnosis for patients presenting with chest pain, electrocardiographic changes or troponin rise and normal coronary arteries : insights from Cardiovascular MRI in our population1495Early Predictive Factors of LV Remodeling after STEMI ; Assessment by Coronary Angiogram and Cadiovascular Magnetic Resonance1497The Pathobiologic Mechanisms and the Prognostic Meaning of t wave Inversion in Acute Myocarditis. a Study Performed by Cardiac Magnetic Resonance1501The Influence of Left Atrial Function on Exercise Tolerance in Patients with Heart Failure and Preserved Ejection Fraction : A Cardiac Magnetic Resonance Feature Tracking Study1504Microvascular Obstruction in Patients with Anterior ST-Elevation Myocardial Infarction who Underwent Primary Percutaneous Coronary Intervention : Predictors and Impact on the Left Ventricular Function1508Histological Validation of ECV Quantification by Cardiac Magnetic Resonance T1 Mapping in Cardiac Amyloidosis1513Comparative Evaluation of Flow Quantification Across the Atrioventricular Valve in Patients with Functional Univentricular Heart After Fontan's Surgery and Healthy Controls : Measurement by 4D Flow Magnetic Resonance Imaging and Streamline Visualization1515Does arterial switch for d-transposition of the great arteries alter myocardial deformation of the ventricles?1527Accuracy of T1 Mapping by multi-professional CMR operators to predict myocardial infarct1531Detecting hypertensive heart disease : the additive value of cardiovascular magnetic resonance imaging1534Diagnostic Performance of Cardiac Magnetic Resonance Strain Parameters in Assesment of Myocardial Ischemia1535Relationships between left ventricular filling pressures and longitudinal dysfunction with myocardial fibrosis in uncomplicated hypertensive patients1539Predictive Clinical Factors of Tissue Damage Severity in Reperfused Acute Myocardial Infarction as Visualized by Cardiac Magnetic Resonance1541Which CMR derived parameter predicts better the need of invasive treatment in aortic coarctation?1543Contrast-enhanced magnetic resonance tomography in patients with supraventricular tachyarrhythmias1546Prognostic Value of CMR Imaging Biomarkers on Outcome in Peripheral Arterial Disease : a 6-year Follow-up Pilot Study1549Dobutamine-Stress-CMR in Young Adults after Arterial Switch Operation as Neonates1553Impact of posteromedial papillary muscle infarction on mitral regurgitation after ST-segment elevation myocardial infarction1556Role of cardiac magnetic resonance imaging in assessment of left ventricular hypertrophy1569Using intrinsic Cardiac Shear Waves to measure Myocardial Stiffness : Preliminary results from Patients with Heart failure with preserved Ejection Fraction1571Relationship of cerebrovascular reactivity and MRI pattern of carotid atherosclerotic plaque1577Feasibility study of an MR conditional pedal ergometer for cardiac stress MRI–preliminary results in healthy volunteers and patients with suspected coronary artery disease1581Pulmonary valve replacement for severe pulmonary stenosis has a positive effect on left ventricular remodeling1582The RV after cardiac surgery, more resilient than thought : multiparametric quantification shows altered rather than reduced function1584Usefulness of cardiovascular magnetic resonance to differentate coronary artery disease from non ischemic cardiomyoptathy in patients with heart failure1593What does CMR add to the ESC Risk Prediction Model to Assess the Occurrence of Sudden Cardiac Death in Patients with HCM?1597Detecting Progression of Diffuse Interstitial Fibrosis in Alstrom Syndrome1612Diffuse fibrosis in the ventricles of patients with transposition of great arteries late after atrial switch1631Utility of Cardiac Magnetic Resonance in the diagnosis and stratification of arrhythmic risk in patients with confirmed or suspected ventricular arrhythmias1635Size matters : pulmonary veins geometry by cardiac magnetic resonance imaging in atrial fibrillation patients1642How do the differences in Left Ventricular wall measurements from Echocardiography and CMR in patients with Hypertrophic Cardiomyopathy affect current Sudden Cardiac Death Risk Scores?1651Noninvasive assessment of intracardiac viscous energy loss in Fontan patients from 4D Flow CMR1653Behcet and Myocardial Infarction : A Rare Combination1328Impact of New Cerebral Ischemic Lesions On the Occurrence of Delirium after Transcatheter Aortic Valve Implantation1329Heart T2* assessment to measure iron overload using different software tools in patients with Thalassemia Major1332Hypertrabeculated Left Ventricle at Cardiac Magnetic Resonance Imaging : β-Thalassemia Major vs. Left Ventricular Non -Compaction Disease1335Aortic Regurgitation following Transcatheter Aortic Valve Implantation (TAVI) : a CMR Study of two prosthesis designs1336Incremental value of semi-quantitative evaluation of myocardium perfusion with 3T stress cardiac MRI1343Left ventricular morphological quantification with single shot and free-breathing SSFP cine imaging compared with standard breath-hold SSFP cine imaging1344Changes of cardiac iron and function during pregnancy in transfusion-dependent thalassemia patients1346Significant improvement of survival by T2* MRI in thalassemia major1350The impact of trans-catheter aortic valve implantation induced left-bundle branch block on cardiac reverse remodelling1351Value of magnetic resonance myocardial perfusion imaging in patients with indeterminate coronary computed tomography angiography results1353Gender differences in response to Transcatheter Aortic Valve implantation in patients with severe aortic stenosis assessed by feature tracking1354A qualitative assessment of first-pass perfusion bolus timings in the assessment of myocardial ischemia : A magnetic resonance study1355MRI prospective survey on cardiac iron and function and on hepatic iron in non transfusion-dependent thalassemia intermedia patients treated with desferrioxamine or non chelated1358Coronary Calcification Compromises Myocardial Perfusion Irrespective of Luminal Stenosis1359Non–contrast three–dimensional magnetic resonance imaging for pre–procedural assessment of aortic annulus dimensions in patients undergoing transcatheter aortic valve implantation1360“Systolic ventricularization” of the left atrium with bileaflet mitral valve prolapse : impact on quantification of mitral regurgitation1361CMR assessment of left ventricular remodeling 6 months after percutaneous edge-to-edge repair using Mitraclip1363Accuracy of Transthoracic Echocardiography (TTE) in comparison with Cardiac Magnetic Resonance (CMR)1374CMR for myocardial iron overload assessment : a new calibration curve from the MIOT project1381Can Speckle Tracking Imaging Reveal Myocardial Iron Overload in Thalassemia Major ? A Combined Echocardiography and Cardiac Magnetic Resonance Study1382Native myocardial T1 mapping in patients with pulmonary hypertension and age matched volunteers1384A Insidious Line Between Thalassemia Intermedia And Left Ventricular Non-Compaction Disease : The Role Of Cardiac Magnetic Resonance1388Pulmonary Artery : Ascending Aorta Diameter - An Important and Easily Measureable Prognostic Parameter1394Novel carotid artery ultrasound index–Extra-media thickness and a well-established cardiac magnetic resonance fat quantification method1403Validation of CMR-derived LVOT diameters against direct in-vivo measurements1409Early myocardial perfusion measured by CMR in acute myocardial infarction treated by primary PCI–a postconditioning study1420Assessment of paravalvular aortic regurgitation after transcatheter aortic valve implantation using cardiac magnetic resonance imaging : a comparative study with echocardiography and angiography1422Left atrial strain measured by feature tracking predicts left ventricular end diastolic filling pressure1426Validation of extracellular volume equation by serial cardiac magnetic resonance imaging measurements in patients with varying hematocrit1427Assessing diastolic function applying Cardiovascular Magnetic Resonance - comparison with the gold standard1475Role of Adenosine Stress Cardiac Mri in the Setting of Chronic Total Occlusion of Coronary Arteries1520Aortic Elasticity Indexes by Magnetic Resonance Predict Progression of Ascending Aorta Dilation1522Combined atrioventricular assessment of diastolic function by cardiac magnetic resonance1537Safety, image quality and clinical utility of cardiac magnetic resonance in patients with antiarrhythmic devices1538Usefulness of cardiac magnetic resonance to predict the need for surgical procedures in patients with mitral regurgitation1550Normal T1, T2, T2* and extracellular volume reference values in healthy volunteers at 3 Tesla cardiac magnetic resonance1551Comprehensive intra-ventricular myocardial deformation strain analysis in healthy volunteers : implications for regional myocardial disease processes1557Elastic properties changes of aorta in patients with dilatation of the ascending aorta evaluated by Magnetic Resonance1558The prevalence of active myocarditis assessed by cardiovascular magnetic resonance in patients with clinically suspected myocarditis1563Quantitative assessment of myocardial scar heterogeneity using texture analysis to risk stratify post–MI patients for ICD insertion1564Gender differences in exercise capacity and LV remodeling in response to pressure overload in aortic stenosis1572Myocardial wall stress as a novel CMR measure to assess cardiac function1573Feature tracking cardiac magnetic resonance to assess LV mechanics in pressure and volume overload1574Safety, feasibility and clinical impact of Cardiovascular Magnetic Resonance in patients with MR-conditional devices1576T1 Mapping at 1-Year Following Aortic Valve Replacement : Baseline Geometry Defines Magnitude of Fibrosis Regression1583Normal values of LV global myocardial mechanics using two and three-dimensional cardiovascular magnetic resonance1585Prediction of infarct transmurality in acute myocardial infarction based on cardiac magnetic resonance deformation analysis1595Measuring invasive blood pressure by catheters guided solely by Cardiovascular Magnetic Resonance by using a new guidewire without the need of a hybrid CMR-fluoroscopy suite1599Influence of active and passive cardiac implants on CMR image quality : results from a consecutive patient series1600Reproducibility of aortic 4D flow measurements in healthy volunteers1601An automatic approach to extract 4D flow hemodynamic markers : application in BAV-affected patients1602Global myocardial mechanics with 2 and 3-Dimensional cardiovascular magnetic resonance feature tracking in patients with myocarditis1603A CMR-based clinician-friendly assessment of in vivo left ventricle hemodynamics1604Reproducibility of left atrial strain using cardiovascular magnetic resonance myocardial feature tracking1605The severity of myocardial infarction in STEMI, determined by transmurality of infarct and infarct characteristics, impacts on myocardial T2 values1606MicroRNA as potential biomarkers of acute myocardial damage following STEMI1607Myocardial blush grade is associated with microvascular obstruction on CMR following STEMI16084D Flow CMR imaging : Comparison of conventional parallel imaging and variable density k-t acceleration1609In-vitro comparison of segmented-gradient-echo versus non-segmented echo planar imaging 4D Flow CMR : validation of flow volume and 3D vortex ring assessment1614Not just 2D but also 4D flow measurements in pulsatile phantom are accurate and reproducible1615Diffusion Tensor Imaging : Comparison of Hypertrophic Cardiomyopathy, Hypertension and Healthy Cohorts1624Impact of myocardial fibrosis measured by cardiac magnetic resonance imaging on reverse left ventricular remodelling after transcatheter aortic valve implantation1625Prosthetic valve regurgitation after transcatheter aortic valve implantation with new-generation devices compared to surgical aortic valve replacement–a cardiac magnetic resonance imaging flow measurement analysis1637Assessment of Aortic and Pulmonary Artery stiffness in Patients with COPD using Cardiac Magnetic Resonance1638Myocardial Mechanics implications using 2D Cardiovascular Magnetic Resonance in Aortic Regurgitation1639Delineation of myocardial infarction & ; viability by 12 lead ECG vs cardiac magnetic resonance1641Regional variation in native T1 values in normal healthy volunteers?1645Feasibility of myocardial strain assessment using tissue tracking at 3.0T CMR following ST-segment elevation myocardial infarction1648Diagnostic Impact of Cardiac Magnetic Resonance in patients with acute chest pain, troponin elevation and no significant angiographic coronary artery disease ». European Heart Journal – Cardiovascular Imaging 17, suppl 1 (mai 2016) : i37—i84. http://dx.doi.org/10.1093/ehjci/jew183.

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Lunsford, Kurt G. « Can Yield Curve Inversions Be Predicted ? » Economic Commentary (Federal Reserve Bank of Cleveland), 16 juillet 2018, 1–6. http://dx.doi.org/10.26509/frbc-ec-201806.

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An inverted Treasury yield curve—a yield curve where short-term Treasury interest rates are higher than long-term Treasury interest rates—is a good predictor of recessions. Because of this, economists and policymakers often assess the risk of a yield curve inversion when the yield curve is flattening. I study the forecastability of yield curve inversions. Professional forecasters did not predict the beginning of the yield curve inversions prior to the 1990–1991, 2001, and 2008–2009 recessions. In all three cases, professional forecasters failed to predict the magnitude of the rise in short-term interest rates. Prior to the 2008–2009 recession, forecasters also overpredicted long-term interest rates.

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Engstrom, Eric C., et Steven A. Sharpe. « (Don't Fear) The Yield Curve, Reprise ». FEDS Notes 2022, n^o 3099 (25 mars 2022). http://dx.doi.org/10.17016/2380-7172.3099.

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In recent months, financial market perceptions about the future path of short-term interest rates have evolved amidst signals from policymakers suggesting that reduced monetary policy accommodation is in the offing. As with previous episodes of policy tightening, most recently in 2018, one can hear an attendant rise in the volume of commentary about a decline in the slope of the yield curve and the risk of "inversion," whereby long-term yields fall below shorter-maturity yields.

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« Predictability of Yield Curve Inversion and Moving Average Crossover ». Journal of Accounting and Finance 20, n^o 4 (4 octobre 2020). http://dx.doi.org/10.33423/jaf.v20i4.3114.

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Grasso, Adriana, et Filippo Natoli. « Consumption Volatility Risk and the Inversion of the Yield Curve ». SSRN Electronic Journal, 2018. http://dx.doi.org/10.2139/ssrn.3160780.

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Grasso, Adriana, et Filippo Natoli. « Consumption Volatility Risk and the Inversion of the Yield Curve ». SSRN Electronic Journal, 2018. http://dx.doi.org/10.2139/ssrn.3161302.

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Burgess, Nicholas. « Are We Heading into a Recession ? Yield Curve Inversion as a Recession Predictor ». SSRN Electronic Journal, 2019. http://dx.doi.org/10.2139/ssrn.3448739.

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Anderson, Richard G. « Yield Curve Inversions and Cyclical Peaks ». Economic Synopses 2006, n^o 10 (2006). http://dx.doi.org/10.20955/es.2006.10.

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