Field migration rates of tidal meanders recapitulate fluvial morphodynamics

The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidalmeander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths

On the O'Brien-Jarrett-Marchi law

The relationship between the total water volume entering a lagoon during a characteristic tidal cycle (i.e., the prism) and the size of its inlet is well established empirically since the classic work of O'Brien and Jarrett widely cited in the geomorphic and hydrodynamic literature. Less known is a rather deep theoretical explanation proposed by Marchi. This paper reviews the empirical and theoretical evidence on which the relation is based, setting the various theoretical approaches so far pursued within the general framework ensured by Marchi's theoretical treatment of the problem. We conclude that the depth of the empirical and theoretical validations and the breadth and the importance of its implications suggest that the O'Brien-Jarrett-Marchi law relating the minimum inlet cross-sectional area and the tidal prism flowing through it may be referred to thereinafte

High-yield fabrication of entangled photon emitters for hybrid quantum networking using high-temperature droplet epitaxy

Several semiconductor quantum dot techniques have been investigated for the generation of entangled photon pairs. Among the other techniques, droplet epitaxy enables the control of the shape, size, density, and emission wavelength of the quantum emitters. However, the fraction of the entanglement-ready quantum dots that can be fabricated with this method is still limited to around 5%, and matching the energy of the entangled photons to atomic transitions (a promising route towards quantum networking) remains an outstanding challenge. Here, we overcome these obstacles by introducing a modified approach to droplet epitaxy on a high symmetry (111)A substrate, where the fundamental crystallization step is performed at a significantly higher temperature as compared to previous reports. Our method drastically improves the yield of entanglement-ready photon sources near the emission wavelength of interest, which can be as high as 95% due to the low values of fine structure splitting and radiative lifetime, together with the reduced exciton dephasing offered by the choice of GaAs/AlGaAs materials. The quantum dots are designed to emit in the operating spectral region of Rb-based slow-light media, providing a viable technology for quantum repeater stations.Comment: 14 pages, 3 figure

Boosting the power performance of multilayer graphene as lithium-ion battery anode via unconventional doping with in-situ formed Fe nanoparticles

Graphene is extensively investigated and promoted as a viable replacement for graphite, the state-of-the-art material for lithium-ion battery (LIB) anodes, although no clear evidence is available about improvements in terms of cycling stability, delithiation voltage and volumetric capacity. Here we report the microwave-assisted synthesis of a novel graphene-based material in ionic liquid (i.e., carved multilayer graphene with nested Fe3O4 nanoparticles), together with its extensive characterization via several physical and chemical techniques. When such a composite material is used as LIB anode, the carved paths traced by the Fe3O4 nanoparticles, and the unconverted metallic iron formed in-situ upon the 1st lithiation, result in enhanced rate capability and, especially at high specific currents (i.e., 5 A g−1), remarkable cycling stability (99% of specific capacity retention after 180 cycles), low average delithiation voltage (0.244 V) and a substantially increased volumetric capacity with respect to commercial graphite (58.8 Ah L−1 vs. 9.6 Ah L−1)

A Distributed Approach to solve Power Flow problems in new emerging scenarios

Distributed Computing is growing up in interest in many applied fields of scientific research. Power system operation is becoming increasingly complex due to the Distributed Energy Resources (DERs) integration at various voltage levels. In this context, the need to automate grid operation is ever fundamental in order to ensure adequate levels of reliability, flexibility and cost effectiveness of power systems. This report shall be intended as a support for the understanding of methodological aspects and principles for the solution of power flow equations through a distributed approach, in a context where multiple interacting entities share a portion of their grids and want to align their computation in an automated way. The aim is both to give the reader a comprehensive overview of the software used for the implementation, the Portable Scientific Extensible Toolkit for Scientific Computation - PETSc, and the principles followed to build the Distributed Power Flow Solver as well as the specific features that make it different from other distributed solvers available in the literature. Additionally, two frameworks are presented as potential applications for the model. The European transmission networks level, in the context of capacity calculation, and the transmission-distribution networks coupling. In the beginning a short literature review on both frameworks is presented.JRC.C.3-Energy Security, Distribution and Market

Training in Emergency Surgery

Although emergency surgery accounts for 50% of the surgery cases in hospitals in Italy, in 57% of the hospitals emergency surgery is not performed by a dedicated team. In Europe, numerous surveys have shown that 50% of the young surgeons desire a more complete training in emergency general surgery (EGS). A survey conducted by the Association of Surgeons in training in the UK has shown that trainees want greater competence in EGS (92.4%) through the adoption of specific programs and training protocols. The Italian Society of Emergency Surgery and Trauma (SICUT)) has decided to try to make up for this lack of training by organizing specific courses that can serve as a training pathway in EGS. KEY WORDS: Emergency Surgery, Training