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Background: In this study we used event‐related potentials (ERPs) and source localization analyses to track the time course of neural activity underlying response monitoring in children diagnosed with an anxiety disorder compared to age‐matched low‐risk normal controls. Methods: High‐density ERPs were examined following errors on a flanker task from 12 children between 8 and 14 years old diagnosed with an anxiety disorder (ANX) and 13 age‐matched low‐risk normal controls (LRNC). Results: Children diagnosed with an anxiety disorder had increased error‐related negativity (ERN) amplitude. The neural generators of the ERN in the ANX group were estimated to be localized in the anterior cingulate cortex (ACC). There were no significant group differences in P E amplitude. Conclusions: These data provide evidence for increased ERN amplitude localized to the ACC in children diagnosed with an anxiety disorder, suggesting altered maturational patterns of the ACC circuitry early in the course of this illness.
Current state-of-the-art Na-ion battery cathodes are selected from the broad chemical space of layered first-row transition-metal (TM) oxides. Unlike their lithium-ion counterparts, seven first-row layered TM oxides can intercalate Na ions reversibly. Their voltage curves indicate significant and numerous reversible phase transformations during electrochemical cycling. These transformations are not yet fully understood but arise from Na-ion vacancy ordering and metal oxide slab glide. In this study, we investigate the nature of vacancy ordering within the O3 host lattice framework. We generate predicted electrochemical voltage curves for each of the Na-ion intercalating layered TM oxides by using a high-throughput framework of density-functional-theory calculations. We determine a set of vacancy-ordered phases appearing as ground states in all Na[subscript x]MO[subscript 2] systems and investigate the energy effect of the stacking of adjacent layers.
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In this paper, we study communication systems, modulators, and demodulators using chaotic systems from the perspective of reconstruction of attractors. We consider a two-step approach to the recovery of information signals from chaotic modulation. To recover the information signal modulated by a chaotic dynamical system, the first step is to reconstruct the chaotic attractor given a subset of the state variables. The second step is to reconstruct the information signal from the chaotic attractors. Two main techniques to accomplish this are the Takens reconstruction theorem and the chaotic synchronization theorem. In general, a combination of these two techniques are needed to recover the information signal. We show a systematic way to reconstruct an attractor and the injected signal exactly from a scalar observable for a subclass of Lur'e systems. We illustrate this approach using several examples. Extensions to discrete-time systems are also presented.
Critical fracture stress and stress modified fracture strain models are utilized to describe the variation of lower and upper shelf fracture toughness with temperature and strain rate for two alloy steels used in the manufacture of nuclear pressure vessels, namely SA533B-1 (HSST Plate 02) and SA302B (Surveillance correlation heat). Both steels have been well characterized with regard to static and dynamic fracture toughness over a wide range of temperatures (−190 to 200°C), although validJ Ic measurements at upper shelf temperatures are still somewhat scarce. The present work utilizes simple models for the relevant fracture micromechanisms and local failure criteria to predict these variations in toughness from uniaxial tensile properties. Procedures are discussed for modelling the influence of neutron fluence on toughness in irradiated steel, and predictions are derived for the effect of increasing fluence on the variation of lower shelf fracture toughness with temperature in SA533B-1.
Analytical expressions and numerical results are presented for the complex-valued, dynamic (frequency dependent), flexibility influence coefficients for a homogeneous, isotropic, linearly viscoelastic half space in plane strain or generalized plane stress. These influence coefficients, defined for uniformly spaced nodal points at the surface of the half plane, are obtained from solutions of two boundary value problems, associated with harmonically time-varying (eiωt) stresses uniformly distributed between two adjacent nodal points. Numerical values for these coefficients are presented for a viscoelastic half plane of constant hysteretic material. A method is developed to determine from these results the dynamic stiffness matrix, associated with the nodal points at the base of a surface supported structure, for the half plane. The resulting dynamic stiffness matrix is shown to be superior compared to the one determined from an available procedure, which is based on solutions of displacement boundary value problems for the half plane.
