Physiographic influences on dense shelf-water cascading down the Antarctic continental slope

Predicting the source areas for Antarctic Bottom Water (AABW) requires knowledge of how cold, dense water masses form and move from the Antarctic shelves to the continental slope. Here we use a review of nearly 50 years of direct hydrographic observations to infer the main broad-scale influences on the distribution of dense shelf-water (DSW) overflows that cascade down the continental slope around Antarctica. The dynamics and distribution of large ice shelves, coastal polynyas and the physiography of the Antarctic continental shelves are each considered. The catalogue we present increases the number of DSW observations to 27, adds 20 additional stations where this process is likely to have occurred, and identifies 41 areas where DSW appears to be absent. Our pan-Antarctic, multi-decadal review enhances the understanding of the formation and export of DSW and highlights the variability and complexity of ice-ocean systems on high-latitude continental margins. The study also provides a context for understanding recent episodes of Antarctic ice-shelf instability, and how the relationship between DSW and AABW may evolve with climatic and oceanographic changes

An experimental approach to submarine canyon evolution

We present results from a sandbox experiment designed to investigate how sediment gravity flows form and shape submarine canyons. In the experiment, unconfined saline gravity flows were released onto an inclined sand bed bounded on the downstream end by a movable floor that was used to increase relief during the experiment. In areas unaffected by the flows, we observed featureless, angle-of-repose submarine slopes formed by retrogressive breaching processes. In contrast, areas influenced by gravity flows cascading across the shelf break were deeply incised by submarine canyons with well-developed channel networks. Normalized canyon long profiles extracted from successive high-resolution digital elevation models collapse to a single profile when referenced to the migrating shelf-slope break, indicating self-similar growth in the relief defined by the canyon and intercanyon profiles. Although our experimental approach is simple, the resulting canyon morphology and behavior appear similar in several important respects to that observed in the field

Imaging the seascapes of the Mediterranean

The Mediterranean Sea is a relative newcomer to Earth"s landscape. Due to its complex tectonic history, this mid-latitude sea is composed of a cluster of basins. Their seascape is in most cases dominated by geologically young structures, but also by sedimentary processes. Among the latter, sedimentary processes related to the dynamics of the largest rivers in the Mediterranean (Ebro, Rhône, Po, Danube, and Nile) stand out. This overview article illustrates the main sedimentary processes and their products contributing to shape the Mediterranean seascape within a source-tosink approach. To highlight this approach, this article mainly focuses on one of the EUROSTRATAFORM project study areas: the northwestern Mediterranean

Bathymetric extent of recent trawl damage to the seabed captured by an ROV transect in the Alboran Sea

Bottom trawl fishing is among the most destructive anthropogenic pressures acting on benthic ecosystems, but the full extent of the damage is undocumented because of the limited number of deep-sea observations of impacted regions (e.g., Brennan et al., 2012, 2016). As part of its continuing ocean exploration mission, in 2011, E/V Nautilus conducted a remotely operated vehicle (ROV) survey along a transect in a submarine canyon in the Mediterranean's Alboran Sea off southern Spain at depths ranging from 1,200 m to <300 m (Coleman et al., 2012). This exploration along the South Alboran Ridge offered the opportunity to directly observe with video the bathymetric extent and intensity of recent trawling damage to the seafloor in this area. This dive revealed large furrows running in multiple directions caused by trawl doors scraping across the seabed. Little biological activity was evident in the depth ranges where these scars were observed. The destructive nature of bottom trawl fishing should be viewed with the same public affront as subaerial clear-cutting of forests and strip-mining. The only difference is that the ocean hides trawl damage from the public eye. The more we explore the deep sea, repeatedly map the seafloor with sonar, and observe the seabed and its ecosystems with video captured by ROVs, the greater we can understand the full impacts of trawling

Evolution of submarine canyon-fan systems in fault-controlled margins: Insights from physical experiments

Different fault settings make the morphology of submarine canyon-fan systems on active margins complex and diverse. In this study we explore the continuum of erosion, transport and sedimentation processes taking place in fault-controlled canyon-fan systems by using physical experiments and a morphodynamic model. Based on morphometric analyses we show how Hack's scaling relationships exist in submarine canyons and fans. The DEM of differences (DoDs) demonstrate the growth patterns and allow to establish relevant relationships between volumes of canyons and their corresponding fans. We reveal strong self-similarities on canyon-fan long profiles and, through a new morphodynamic model, we capture their evolution over time, including the trajectory of internal moving boundaries. We observe that fault slip rate controls the merging speed of coalescent submarine canyon-fan systems and, when coupling fault slip rate with inflow discharge, a competitive influence arises. In this study we also uncover scaling relationships spanned from laboratory to field-scale. Overall, our findings are inspiring and valuable for field investigators and modelers to better interpret and predict the morphological evolution and sedimentary processes of submarine canyon-fan systems in active fault settings

VIG-Express: Consensus on an express multidimensional/geriatric assessment system in Catalonia

[spa] Objetivo: Consensuar una herramienta de valoración multidimensional/geriátrica rápida (VMGR), como sistema compartido y universal de valoración multidimensional de personas con multimorbilidad, fragilidad, complejidad o situación avanzada, para todos los profesionales del sistema de salud y social de Catalun ̃a. Disen ̃o: Consenso de profesionales en tres fases, combinando sesiones presenciales con trabajo telemático. Emplazamiento: Catalun ̃a. Participantes: Se constituyó un grupo de 27 profesionales de carácter interdisciplinario repre- sentativo de los distintos ámbitos de atención. Método: Se han combinado las metodologías de Design thinking para el consenso inicial de características de la herramienta de VMGR (fase 1), con la metodología Lean Start-Up para el disen ̃o de la nueva herramienta de VMGR (fase 2), que finalmente se testeó en un grupo de pacientes (fase 3). Resultados: En la fase 1 se consensuó que la herramienta de VMGR ideal debía permitir una valoración ad hoc de las personas, ser rápida y ágil (tiempo < 10 minutos), identificar las dimen- siones alteradas mediante preguntas trigger y facilitar el diagnóstico de situación (idealmente cuantificado). En la fase 2 se elaboró el prototipo de una nueva herramienta de VMGR de 15 + dos preguntas (VIG-Express), finalmente testeada en 35 personas en la fase 3. Conclusiones: En los resultados preliminares, la herramienta VIG-Express parece facilitar una valoración multidimensional sencilla y rápida y la personalización de las intervenciones, así como una mirada única y un relato compartido entre los profesionales de los distintos ámbitos de atención. Serán necesarios más estudios para corroborar estos hallazgos. [spa] Objective: To reach a consensus on an rapid multidimensional/geriatric assessment (RMGA) tool for all health and social professionals of Catalonia as a shared and universal system to assess patients with multimorbidities, frailty, complexity or advanced conditions. Design: Three-phase consensus of professionals, combining in-person sessions with telematics. Location: Catalonia. Participants: A group of 27 interdisciplinary professionals from different care settings. Method: The Design Thinking methodology for an initial consensus on the characteristics of the RMGA tool (Phase 1) has been combined with the Lean Startup methodology to create a new RMGA tool (Phase 2), and then tested in a group of patients (Phase 3). Results: In Phase 1, a consensus was reached that the perfect RMGA tool should allow for an ad hoc assessment of patients, be fast and flexible (<10 min), identify altered dimensions using trigger questions and facilitate the diagnosis of the condition (ideally quantified). In Phase 2, a prototype of a new RMGA tool containing 15 + 2 questions (VIG-Express) was developed, which was then tested in 35 patients in Phase 3. Conclusions: Based on preliminary results, the VIG-Express tool seems to facilitate a simple, rapid multidimensional assessment and the customization of interventions, as well as provide a unique look and shared narrative between professionals from different care settings. More studies will be required to corroborate these findings

Using illness trajectories to inform person-centred, advance care planning

What you need to know- Most patients with progressive illness follow characteristic trajectories of decline, previously identified as rapid, intermittent, or a gradual decline from a low baseline- Multimorbidity is increasingly common and follows a distinct fourth trajectory- An understanding of the dynamic multidimensional trajectories of patients with progressive illnesses helps clinicians consider individual holistic needs and have meaningful conversations with patients and families about advance care planning- In patients with an acute deterioration in health (such as from an infection), considering the main underlying illness trajectory helps guide shared decision making about realistic current and future treatment and care option

Reliability, validity and feasibility of the frail-vig index

The study aimed to assess the reliability of the scores, evidence of validity, and feasibility of the Frail-VIG index. A validation study mixing hospitalized and community-dwelling older people was designed. Intraclass correlation coefficient (ICC) was used to assess the inter-rater agreement and the reliability. The construct validity of the Frail-VIG index with respect to the Frailty Phenotype (FP) was evaluated by calculating the area under the receiver operating characteristic curve (AUC-ROC). Convergent validity with the Clinical Frailty Scale (CFS) was assessed using Pearson's correlation coefficients. The feasibility was evaluated by calculating the average time required to administer the Frail-VIG index and the percentage of unanswered responses. A sample of 527 older people (mean age of 81.61, 56.2% female) was included. The inter-rater agreement and test-retest reliability were very strong: 0.941 (95% CI, 0.890 to 0.969) and 0.976 (95% CI, 0.958 to 0.986), respectively. Results indicated adequate convergent validity of the Frail-VIG index with respect to the FP, AUC-ROC 0.704 (95% CI, 0.622 to 0.786), and a moderate to strong positive correlation between the Frail-VIG index and CFS (r = 0.635, 95% CI, 0.54 to 0.71). The Frail-VIG index administration required an average of 5.01 min, with only 0.34% of unanswered responses. The Frail-VIG index is a reliable, feasible, and valid instrument to assess the degree of frailty in hospitalized and community-dwelling older people

Transient erosion in the Valencia Trough turbidite systems, NW Mediterranean Basin

Submarine canyons can efficiently drain sediments from continental margins just as river systems do in subaerial catchments. Like in river systems, submarine canyons are often arranged as complex drainage networks that evolve from patterns of erosion and deposition. In the present paper we use a morphometric analysis of submarine canyon-channel long-profiles to study the recent sedimentary history of the Valencia Trough turbidite system (VTTS) in the NW Mediterranean Sea. The VTTS is unique in that it drains sediment from margins with contrasting morphologies through a single "trunk" conduit, the Valencia Channel. The Valencia Channel has been active since the late Miocene, evolving in response to Plio-Quaternary episodes of erosion and deposition. The integrated analysis of long-profiles obtained from high-resolution bathymetric data across the entire turbidite system shows evidence for transient canyon incision in the form of knickpoints and hanging tributaries. Multiple factors appear to have triggered these periods of incision. These include a large debris flow at 11,500 yr BP that disrupted the upper reaches of the VTTS and glacio-eustatic lowstands that forced shifting of sediment input to the VTTS. Based on these inferences, long-term time-averaged incision rates for the Valencia Channel have been estimated. The evidence we present strongly suggests that Foix Canyon has played a key role in the drainage dynamics of the VTTS in the past. This study builds conceptually on a recent modeling study that provides a morphodynamic explanation for the long-term evolution of submarine canyon thalweg profiles. The procedure and results from this work are of potential application to other submarine sediment drainage systems, past and present, including those containing mid-ocean type valleys like the Valencia Channel

High-Performance Compression of Multibeam Echosounders Water Column Data

Over the last few decades, multibeam echosounders (MBES) have become the dominant technique to efficiently and accurately map the seafloor. They now allow to collect water column acoustic images along with the bathymetry, which is providing a wealth of new possibilities in oceans exploration. However, water column imagery generates vast amounts of data that poses obvious logistic, economic, and technical challenges. Surprisingly, very few studies have addressed this problem by providing efficient lossless or lossy data compression solutions. Currently, the available options are only lossless, providing low compression ratios at low speeds. In this paper, we adapt a data compression algorithm, the Fully Adaptive Prediction Error Coder (FAPEC), which was created to offer outstanding performance under the strong requirements of space data transmission. We have added to this entropy coder a specific pre-processing stage tailored to theKongsbergMaritime water column file formats. Here, we test it on data acquired with Kongsberg MBES models EM302, EM710, andEM2040.With this bespoke pre-processing, FAPEC provides good lossless compression ratios at high speeds, whereas lossy ratios reach water column file sizes even smaller than bathymetry raw files still with good image quality. We show the advantages over other lossless compression solutions, both in terms of compression ratios and speed.We illustrate the quality of water column images after lossy FAPEC compression, as well as its resilience to datagram errors and its potential for automatic detection of water column targets. We also show the successful integration in ARM microprocessors (like those used by smartphones and also by autonomous underwater vehicles), which provides a real-time solution for MBES water column data compression