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Super rogue waves with an amplitude of up to 5 times the background value are observed in a water-wave tank for the first time. Nonlinear focusing of the local wave amplitude occurs according to the higher-order breather solution of the nonlinear wave equation. The present result shows that rogue waves can also develop from very calm and apparently safe sea states. We expect the result to have a significant impact on studies of extreme ocean waves and to initiate related studies in other disciplines concerned with waves in nonlinear dispersive media, such as optics, plasma physics, and superfluidity.

Since the 1960s, the Benjamin-Feir (or modulation) instability (MI) has been considered as the self-modulation of the continuous “envelope waves” with respect to small periodic perturbations that precedes the emergence of highly localized wave structures. Nowadays, the universal nature of MI is established through numerous observations in physics. However, even now, 50 years later, more practical but complex forms of this old physical phenomenon at the frontier of nonlinear wave theory have still not been revealed (i.e., when perturbations beyond simple harmonic are involved). Here, we report the evidence of the broadest class of creation and annihilation dynamics of MI, also called superregular breathers. Observations are done in two different branches of wave physics, namely, in optics and hydrodynamics. Based on the common framework of the nonlinear Schrödinger equation, this multidisciplinary approach proves universality and reversibility of nonlinear wave formations from localized perturbations for drastically different spatial and temporal scales.

We report the first experimental observation of periodic breathers in water waves. One of them is Kuznetsov–Ma soliton and another one is Akhmediev breather. Each of them is a localized solution of the nonlinear Schrödinger equation (NLS) on a constant background. The difference is in localization which is either in time or in space. The experiments conducted in a water wave flume show results that are in good agreement with the NLS theory. Basic features of the breathers that include the maximal amplitudes and spectra are consistent with the theoretical predictions.

Rogue waves (RWs) can form on the ocean surface due to the well-known quasi-four-wave resonant interaction or superposition principle. The first is known as the nonlinear focusing mechanism and leads to an increased probability of RWs when unidirectionality and narrowband energy of the wave field are satisfied. This work delves into the dynamics of extreme wave focusing in crossing seas, revealing a distinct type of nonlinear RWs, characterised by a decisive longevity compared with those generated by the dispersive focusing (superposition) mechanism. In fact, through fully nonlinear hydrodynamic numerical simulations, we show that the interactions between two crossing unidirectional wave beams can trigger fully localised and robust development of RWs. These coherent structures, characterised by a typical spectral broadening then spreading in the form of dual bimodality and recurrent wave group focusing, not only defy the weakening expectation of quasi-four-wave resonant interaction in directionally spreading wave fields, but also differ from classical focusing mechanisms already mentioned. This has been determined following a rigorous lifespan-based statistical analysis of extreme wave events in our fully nonlinear simulations. Utilising the coupled nonlinear Schrödinger framework, we also show that such intrinsic focusing dynamics can be captured by weakly nonlinear wave evolution equations. This opens new research avenues for further explorations of these complex and intriguing wave phenomena in hydrodynamics as well as other nonlinear and dispersive multi-wave systems.

Instabilities are common phenomena frequently observed in nature, sometimes leading to unexpected catastrophes and disasters in seemingly normal conditions. One prominent form of instability in a distributed system is its response to a harmonic modulation. Such instability has special names in various branches of physics and is generally known as modulation instability (MI). The MI leads to a growth-decay cycle of unstable waves and is therefore related to Fermi-Pasta-Ulam (FPU) recurrence since breather solutions of the nonlinear Schrödinger equation (NLSE) are known to accurately describe growth and decay of modulationally unstable waves in conservative systems. Here, we report theoretical, numerical and experimental evidence of the effect of dissipation on FPU cycles in a super wave tank, namely their shift in a determined order. In showing that ideal NLSE breather solutions can describe such dissipative nonlinear dynamics, our results may impact the interpretation of a wide range of new physics scenarios.

The Peregrine soliton, which is commonly considered to be a prototype of a rogue wave in deep water, is observed and measured in a wave tank. Using the measured data of water elevation, we calculated the spectra of the Peregrine soliton and confirmed that they have triangular shapes, in accordance with the theory. Key Points We calculated the spectra of the observed Peregrine solution We confirmed that the spectra have a triangular shape

Rogue waves in the ocean can take two forms. One form is an elevated wall of water that appears and disappears locally. Another form is a deep hole between the two crests on the surface of water. The latter one can be considered as an inverted profile of the former. For holes, the depth from crest to trough can reach more than twice the significant wave height. That allows us to consider them as rogue events. The existence of rogue holes follow from theoretical analysis but has never been proven experimentally. Here, we present the results confirming the existence of rogue wave holes on the water surface observed in a water wave tank. Key Points Experimental generation of rogue wave holes Rogue waves holes within the framework of the nonlinear Schrodinger equation Rogue wave holes modeled by the Peregrine soliton

ObjectivesEndometrial cancer is the second gynecologic cancer. The varying tumors profile from country to country and the difference in the means available in each country have raised the need for a country-specific guideline. We aim to Present the Tunisian guideline for endometrial cancerMethodsAll relevant international and national scientific literature available from 2016 to 2021 was used to establish this guideline.ResultsThis guideline was made by the Gynecologic Oncology Multidisciplinary team of the National Cancer center. Three questions were asked. What is the actual state of the art?Could it be applied in our country? If not, can we adapt the guideline to our reality?. During the consensus, the panel tried to cope between the actual state of the art and the Tunisian Field reality. The main limitations were the Distant radiation appointment, the patient loss to follow up, and the non-systematic use of biological markers. The 2009 FIGO classification was used to stage our patients. For stage I disease, The ESMO 2016 risk classification was used. One preoperatory and composed of three levels of risks low, intermediate, and high risk. The other classification is post-operatory and comprises low, Intermediate, high-intermediate, and high-risk levels. Based on this Data and our country reality panel developed recommendations.ConclusionsA country-specific guideline based on the international state of the art is more effective to offer the best quality of care available to our patients. It would also point to the lack and what needs to be done to keep on improving the health system.

Wave breaking is the main mechanism that dissipates energy input into ocean waves by wind and transferred across the spectrum by nonlinearity. It determines the properties of a sea state and plays a crucial role in ocean-atmosphere interaction, ocean pollution, and rogue waves. Owing to its turbulent nature, wave breaking remains too computationally demanding to solve using direct numerical simulations except in simple, short-duration circumstances. To overcome this challenge, we present a blended machine learning framework in which a physics-based nonlinear evolution model for deep-water, non-breaking waves and a recurrent neural network are combined to predict the evolution of breaking waves. We use wave tank measurements rather than simulations to provide training data and use a long short-term memory neural network to apply a finite-domain correction to the evolution model. Our blended machine learning framework gives excellent predictions of breaking and its effects on wave evolution, including for external data.