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The process of shoreline change is inherently complex and reliable predictions of shoreline position remain a key challenge in coastal research. Predicting shoreline evolution could potentially benefit from Deep Learning (DL), which is a recently developed and widely successful data-driven methodology. However, so far its implementation for shoreline time series data has been limited. The aim of this contribution is to investigate the potential of DL algorithms to predict interannual shoreline position derived from camera system observations at a New Zealand study site. We investigate the application of Convolutional Neural Networks (CNNs) and hybrid CNN - Long Short-Term Memory networks. We compare our results with two established models, a shoreline equilibrium model, and a model that addresses time scales in shoreline drivers. Using a systematic search and different measures of fitness we found DL models that outperformed the reference models when simulating the variability and distribution of the observations. Overall, these results indicate that DL models have potential to improve accuracy and reliability over current models.

La ricerca sui criteri seguiti nella scelta dei componenti del Sacro Collegio è stato da sempre uno degli aspetti più salienti della storia del Papato, poiché nel corso dei secoli i parametri di giudizio si sono diversificati. Se da una parte si è mantenuto costante il principio di attribuire la porpora a coronamento di un particolare cursus honorum ecclesiastico, dall’altra la scelta dei singoli candidati è cambiata di pari passo alla volontà del Pontefice regnante, le cui decisioni sono state influenzate da una serie di fattori, tra i quali bisogna menzionare l’azione del Segretario di Stato e la pressione della diplomazia internazionale. In questo contesto vanno interpretate anche le nomine decretate sotto Pio XI, il cui pontificato fu costellato dalla convocazione di 17 Concistori, dalla creazione di 76 cardinali e, persino, dalla rinuncia alla porpora di un cardinale francese.

Les cardinaux sont connus du grand public comme des figures prestigieuses des Églises et des sociétés locales. Ils suscitent aussi l’intérêt des médias internationaux par leur rôle, majeur mais toujours mystérieux, dans l’élection du pape. Pourtant, la nature de leur charge et la réalité de leurs fonctions demeurent largement dans l’ombre. Les membres du Sacré Collège composent une élite qui ne ressemble à aucune autre : aristocratique au sens du choix des « meilleurs », et cependant non héréditaire, à fort ancrage local mais aussi très internationalisée, placée à partir des Lumières et de la Révolution face au défi de s’adapter à la modernité. Cet ouvrage est centré sur les aspects spécifiquement romains de l’activité multiforme des « porporati ». Ceux-ci sont saisis à la fois en tant que corps constitué, sede plena (consistoire) et sede vacante (conclave), qu’individuellement, comme responsables de dicastères de la Curie, acteurs majeurs de la diplomatie vaticane, mais aussi protecteurs de congrégations religieuses, dignitaires de la Cour pontificale et détenteurs d’un « titre » cardinalice symbolisant leur ancrage dans la Ville. Les vingt-cinq contributions réunies dans ce volume, accompagnées d’une bibliographie et de plusieurs index, sont le fruit d’un programme de recherches interdisciplinaires qui a rassemblé une équipe internationale d’historiens et d’historiens du droit, et qui a été conduit par l’École française de Rome, l’Institut catholique de Paris et l’Université Paris-Sud.

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Summary Sediment‐stabilizing and ‐destabilizing organisms, i.e. microphytobenthos (biofilms) and macrozoobenthos (bioturbators), affect the erodibility of muddy sediments, potentially altering large‐scale estuarine morphology. Using a novel eco‐morphodynamic model of an idealized estuary, we investigate eco‐engineering effects of microphytobenthos and two macrozoobenthic bioturbators. Local mud erodibility is based on species pattern predicted through hydrodynamics, soil mud content, competition and grazing. Mud resuspension and export is enhanced under bioturbation and prevented under biostabilization through respective exposure and protection of the supra‐ and intertidal. Bioturbation decreases mud thickness and bed elevations, which increases net mud fluxes. Microphytobenthos reduces erosion, leading to a local mud increase of intertidal sediments. In multi‐species scenarios, an effective mud‐prone bioturbator strongly alters morphology, exceeding that of a more abundant sand‐prone moderate species, showing that morphological change depends on species traits as opposed to abundance. Altering their habitat, the effective mud‐prone bioturbator facilitates expansion of the sand‐prone moderate bioturbator. Grazing and species competition favor species distributions of dominant bioturbators. Consequently, eco‐engineering affects habitat conditions while species interactions determine species dominance. Our results show that eco‐engineering species determine the mud content of the estuary, which suggests large effects on the morphology of estuaries with aggravating habitat degradation., Sediment‐stabilizing and ‐destabilizing organisms alter large‐scale estuarine morphology in a novel eco‐morphodynamic model of an idealized estuary. Mud resuspension and export are enhanced under bioturbation and prevented under biostabilization through respective exposure and protection of the supra‐ and intertidal. This leads to reduced mud content and widening of the estuary under bioturbation and muddy confined morphologies under biostabilization. In multi‐species scenarios, eco‐engineering affects habitat conditions which reorganizes species distribution, while species interactions determine species dominance.

Double sandbar systems often characterize the surf zone of wave-dominated beaches and display a variety of poorly explained spatial configurations. Here, we explore the morphodynamic stability of double-barred beaches using a model based on linear stability analysis. Surf zone hydrodynamics are described by coupling depth and wave-averaged conservation of mass and momentum with the wave energy and phase equations, including roller dynamics. A simplified sediment transport formulation relates flow to seabed changes. Under normal wave incidence, an alongshore uniform coast with a cross-shore profile characterized by the presence of two sandbars can be unstable, thereby resulting in the development of crescentic and/or rip channel patterns. Our study demonstrates that sandbar coupling can be either in phase (highs and lows of both sandbars are at the same alongshore position) or out of phase (highs and lows of one sandbar correspond to lows and highs of the other sandbar). In line with observations, results of simulations show a large variability in the possible emerging bottom patterns. Our analysis indicates that modes of which the amplitude of the inner sandbar perturbation is larger than that of the outer sandbar are dominant for large height–depth differences between the two sandbar crests and small offshore wave heights. Patterns related to the outer sandbar dominate for small values of the difference in sandbar depth. For intermediate differences between the two sandbar depths, patterns on both longshore bars appear to be fully coupled (similar growth rates and strongly correlated pattern shapes). For relatively large waves and large depth over the outer sandbar, patterns can also develop close to the shoreline and/or inner surf zone together with patterns in the inner or outer sandbar.

It has been asserted by Vousdoukas et al., that climate change, in particular global sea-level rise (SLR), poses a threat to the existence of sandy beaches. The authors used global data bases of sandy beaches, bathymetry, wave conditions and SLR to drive a simple model based on the ‘Bruun Rule’ to quantitatively evaluate shoreline retreat. To this modelled retreat, they add a background ambient trend in shoreline dynamics and the modelled response of an extreme storm, that together contribute c. 20% of the shoreline retreat. When retreat was more than 100 m by 2100, they declared those beaches extinct. This is an incorrect and potentially damaging finding that must be repudiated along with the associated implications.

Simple stability relationships are practically useful to provide a rapid assessment of coastal and estuarine landforms in response to human interventions and long‐term climate change. In this contribution, we review a variety of simple stability relationships which are based on the analysis of tidal asymmetry (shortened to “TA”). Most of the existing TA‐based stability relationships are derived using the one‐dimensional tidal flow equations assuming a certain regular shape of the tidal channel cross‐sections. To facilitate analytical solutions, specific assumptions inevitably need to be made e.g. by linearising the friction term and dropping some negligible terms in the tidal flow equations. We find that three major types of TA‐based stability relationships have been proposed between three non‐dimensional channel geometric ratios (represented by the ratio of channel widths, ratio of wet surface areas and ratio of storage volumes) and the tide‐related parameter a/h (i.e. the ratio between tidal amplitude and mean water depth). Based on established geometric relations, we use these non‐dimensional ratios to re‐state the existing relationships so that they are directly comparable. Available datasets are further extended to examine theutility of these TA‐based relationships. Although a certain agreement is shown for these relationships, we also observe a large scatter of data points which are collected in different types of landscape, hydrodynamic and sedimentologic settings over the world. We discuss in detail the potential reasons for this large scatter and subsequently elaborate on the limited applicability of the various TA‐based stability relationships for practical use. We highlight the need to delve further into what constitutes equilibrium and what is needed to develop more robust measures to determine the morphological state of these systems.

Infragravity (hereafter IG) waves are surface ocean waves with frequencies below those of wind-generated “short waves” (typically below 0.04 Hz). Here we focus on the most common type of IG waves, those induced by the presence of groups in incident short waves. Three related mechanisms explain their generation: (1) the development, shoaling and release of waves bound to the short-wave group envelopes (2) the modulation by these envelopes of the location where short waves break, and (3) the merging of bores (breaking wave front, resembling to a hydraulic jump) inside the surfzone. When reaching shallow water (O(1–10 m)), IG waves can transfer part of their energy back to higher frequencies, a process which is highly dependent on beach slope. On gently sloping beaches, IG waves can dissipate a substantial amount of energy through depth-limited breaking. When the bottom is very rough, such as in coral reef environments, a substantial amount of energy can be dissipated through bottom friction. IG wave energy that is not dissipated is reflected seaward, predominantly for the lowest IG frequencies and on steep bottom slopes. This reflection of the lowest IG frequencies can result in the development of standing (also known as stationary) waves. Reflected IG waves can be refractively trapped so that quasi-periodic along-shore patterns, also referred to as edge waves, can develop. IG waves have a large range of implications in the hydro-sedimentary dynamics of coastal zones. For example, they can modulate current velocities in rip channels and strongly influence cross-shore and longshore mixing. On sandy beaches, IG waves can strongly impact the water table and associated groundwater flows. On gently sloping beaches and especially under storm conditions, IG waves can dominate cross-shore sediment transport, generally promoting offshore transport inside the surfzone. Under storm conditions, IG waves can also induce overwash and eventually promote dune erosion and barrier breaching. In tidal inlets, IG waves can propagate into the back-barrier lagoon during the flood phase and induce large modulations of currents and sediment transport. Their effect appears to be smaller during the ebb phase, due to blocking by countercurrents, particularly in shallow systems. On coral and rocky reefs, IG waves can dominate over short-waves and control the hydro-sedimentary dynamics over the reef flat and in the lagoon. In harbors and semi-enclosed basins, free IG waves can be amplified by resonance and induce large seiches (resonant oscillations). Lastly, free IG waves that are generated in the nearshore can cross oceans and they can also explain the development of the Earth's “hum” (background free oscillations of the solid earth).