Nonlinear wave interaction in coastal and open seas -- deterministic and stochastic theory

We review the theory of wave interaction in finite and infinite depth. Both of these strands of water-wave research begin with the deterministic governing equations for water waves, from which simplified equations can be derived to model situations of interest, such as the mild slope and modified mild slope equations, the Zakharov equation, or the nonlinear Schr\"odinger equation. These deterministic equations yield accompanying stochastic equations for averaged quantities of the sea-state, like the spectrum or bispectrum. We discuss several of these in depth, touching on recent results about the stability of open ocean spectra to inhomogeneous disturbances, as well as new stochastic equations for the nearshore

Altered structural brain asymmetry in autism spectrum disorder in a study of 54 datasets

Altered structural brain asymmetry in autism spectrum disorder (ASD) has been reported. However, findings have been inconsistent, likely due to limited sample sizes. Here we investigated 1,774 individuals with ASD and 1,809 controls, from 54 independent data sets of the ENIGMA consortium. ASD was significantly associated with alterations of cortical thickness asymmetry in mostly medial frontal, orbitofrontal, cingulate and inferior temporal areas, and also with asymmetry of orbitofrontal surface area. These differences generally involved reduced asymmetry in individuals with ASD compared to controls. Furthermore, putamen volume asymmetry was significantly increased in ASD. The largest case-control effect size was Cohen’s d = −0.13, for asymmetry of superior frontal cortical thickness. Most effects did not depend on age, sex, IQ, severity or medication use. Altered lateralized neurodevelopment may therefore be a feature of ASD, affecting widespread brain regions with diverse functions. Large-scale analysis was necessary to quantify subtle alterations of brain structural asymmetry in ASD

Experimental identification of beams with localized nonlinearities

International audienceThe idea underlying time-frequency identification techniques is that, for certain classes of structural response signals, the availability of a limited number of experimental data can be partially mitigated by taking into account the localization in time of the frequency components of the signals. This paper aims to assess the efficacy of time-frequency and time-scale estimators in the identification of weakly nonlinear systems. The example described refers to a beam characterized by a concentrated nonlinearity, whose first mode and related super-harmonics were seen to simulate a Duffing oscillator. A parametric time-frequency identification was conducted under the assumption that the beam's input/output relationship could be approximated by a certain number of terms of the Volterra series representation, this resulting in a set of diagrams of instantaneous estimators. Though a substantial stability over time was observed only for the estimates associated with linear parameters, the identified model showed a good predictive capacity. Experimental data used in this research come from tests performed on a steel beam tested within the framework of the European research project COST Action F3 on Structural Dynamics

Asklepian Dreaming and the Spirit of Transformational Healing: Linking the Placebo Response to Therapeutic Uses of Self

Asklepian medicine – as an archetype of healing – was underpinned by therapeutic uses of self, which, if understood, could be beneficial to modern healthcare. It is being proposed in this article that therapeutic uses of self from instrumental, authentic and transpersonal perspectives could support the process of endogenous healing. Such therapeutic uses of self could play a pivotal role in activating and enhancing the potential for placebo responses, with spiritual significanc

Prevention and treatment of the post-thrombotic syndrome and of the chronic thromboembolic pulmonary hypertension

none2noPost-thrombotic syndrome (PTS) and chronic thromboembolic pulmonary hypertension (CTEPH) are late complications of venous thromboembolism. The purpose of this review is to present and discuss recently published studies that have improved our knowledge of PTS and CTEPH. The current understanding of the pathophysiology of PTS and CTEPH is discussed as well as the importance of chronic residual venous thrombosis, some polymorphisms of plasminogen activator inhibitor-1, and the current concept of misguided thrombus resolution. The surprising finding that elastic compression stockings may not be effective in preventing PTS and the novel medical treatment in CTEPH are discussed in detail. Novel direct oral anticoagulants show potential for prevention of PTS. No firm conclusions can be drawn on the efficacy of elastic stockings. Novel treatments of CTEPH for inoperable patients and those with persistent pulmonary hypertension after surgery have become available and further research on wider indication for their use is urgently needed.nonePesavento, Raffaele; Prandoni, PaoloPesavento, Raffaele; Prandoni, Paol