Repeated (4D) marine geophysical surveys as a tool for studying the coastal environment and ground-truthing remote-sensing observations and modeling

Sandy beaches and the nearshore environment are dynamic coastal systems characterized by sediment mobilization driven by alternating stormy and mild wave conditions. However, this natural behavior of beaches can be altered by coastal defense structures. Repeated surveys carried out with autonomous surface vehicles (ASVs) may represent an interesting tool for studying nearshore dynamics and testing the effects of mitigation strategies against erosion. We present a one-year experiment involving repeated stratigraphic and morpho-bathymetric surveys of a nearshore environment prone to coastal erosion along the Emilia-Romagna coast (NE Italy), the Lido di Dante beach, carried out between October 2020 and December 2021 using an ASV. Seafloor and subseafloor “snapshots” collected at different time intervals enabled us to delineate the seasonal variability and shed light on key controlling variables, which could be used to integrate and calibrate remote-sensing observations and modeling. The results demonstrated that repeated surveys could be successfully employed for monitoring coastal areas and represent a promising tool for studying coastal dynamics on a medium/short (years/months) timescale

Spatial patterns and drivers of benthic community structure on the northern Adriatic biogenic reefs

The northern Adriatic Sea (NAS) hosts numerous biogenic subtidal reefs that are considered biodiversity hotspots. Several studies have already investigated the origin and biodiversity of these reefs. However, many of them are still unexplored and further knowledge is needed for their conservation. Here, the spatial variability, epibenthic community structure, and environmental features that characterize these habitats were investigated. Fifteen randomly selected reefs were sampled between 2013 and 2017, including some remote sites that have never been studied before. A fuzzy k-means clustering method and redundancy analysis were used to find similarities among sites in terms of epibenthic assemblages and to model relationships with abiotic variables. The results showed that these reefs are highly heterogeneous in terms of species composition and geomorphological features. The results were also consistent with previous studies and highlighted three main types of benthic assemblages defined by the dominance of different organisms, mainly reflecting the coastal-offshore gradient: nearshore reefs, generally dominated by stress-tolerant species; reefs at a middle distance from the coast, characterized by sponges, non-calcareous encrusting algae and ascidians; offshore reefs, dominated by reef builders. However, distance from the coast was not the only factor affecting species distribution, as other local factors and environmental characteristics also played a role. This kind of biogenic reefs in temperate seas are still poorly known. The present work contributed to shed further light on these habitats, by complementing the results of previous studies on their natural diversity, highlighting the specificity of the epibenthic communities of NAS reefs and the need to improve current, still inadequate, conservation measures

Focal-Plane Change Triggered Video Compression for Low-Power Vision Sensor Systems

Video sensors with embedded compression offer significant energy savings in transmission but incur energy losses in the complexity of the encoder. Energy efficient video compression architectures for CMOS image sensors with focal-plane change detection are presented and analyzed. The compression architectures use pixel-level computational circuits to minimize energy usage by selectively processing only pixels which generate significant temporal intensity changes. Using the temporal intensity change detection to gate the operation of a differential DCT based encoder achieves nearly identical image quality to traditional systems (4dB decrease in PSNR) while reducing the amount of data that is processed by 67% and reducing overall power consumption reduction of 51%. These typical energy savings, resulting from the sparsity of motion activity in the visual scene, demonstrate the utility of focal-plane change triggered compression to surveillance vision systems

Biological soil crusts of Arctic Svalbard and of Livingston Island, Antarctica

Biological soil crusts (BSCs) occur in arid and semi-arid regions worldwide including the Polar Regions. They are important ecosystem engineers, and their composition and areal coverage should be understood before assessing key current functional questions such as their role in biogeochemical nutrient cycles and possible climate change scenarios. Our aim was to investigate the variability of BSCs from Arctic Svalbard and the Antarctic Island, Livingston, using vegetation surveys based on classification by functional group. An additional aim was to describe the structure of BSCs and represent a classification system that can be used in future studies to provide a fast and efficient way to define vegetation type and areal coverage. Firstly, this study demonstrates huge areas occupied by BSCs in Arctic Svalbard, with up to 90 % of soil surface covered, dominated by bryophytes and cyanobacteria, and showing an unexpectedly high variability in many areas. Livingston Island has lower percentage coverage, up to 55 %, but is dominated by lichens. Our findings show that both Polar Regions have varied BSC coverage, within the sites and between them, especially considering their harsh climates and latitudinal positions. Secondly, we have classified the BSCs of both areas into a system that describes the dominant functional groups and local geography, creating a simple scheme that allows easy identification of the prevailing vegetation type. Our results represent the first contribution to the description of BSCs based on their functional group composition in Polar Regions

An articulatory silicon vocal tract for speech and hearing prostheses

10.1109/TBCAS.2011.2159858IEEE Transactions on Biomedical Circuits and Systems54339-34

Ultra-low-power electronics for non-invasive medical monitoring

New electronics for non-invasive medical monitoring promise low-cost, maintenance-free, and lightweight devices. These devices are critical in long-term medical measurements and in home-based tele-monitoring services, which are extremely important for the reduction of health care costs. Here, we present several methods for reducing power consumption while retaining precision. In particular, we focus on the monitoring of the heart-because of its importance-and we describe a micropower electrocardiograph, an ultra-low-power pulse oximeter, an ultra-low-power phonocardiograph, an integrated-circuit switched-capacitor model of the heart, and a low-power RF-antenna-powered CMOS rectifier for energy harvesting. We also introduce an ultra-low-power platform for medical monitoring that enables the integration of monitoring circuitry in a wireless, low-cost, and battery-free device, and describe a method for audio localization of the device in case of a medical alarm

A spatially explicit food web model for supporting the management of a marine Natura 2000 site: ongoing efforts at the Tegnùe di Chioggia

As remarked by the recent European legislation (MSPD), plans managing the interaction between conservation goals and maritime uses should consider the spatial dimension, to be effective and easily applied. In such a context, food web modelling, considering both the structure and functioning of an ecosystem, is increasingly perceived as an important resource informing sea planning, at the different spatial scales. In this preliminary work, an existing food web model (based on Ecopath with Ecosim) of the northern Adriatic Sea was spatialized and downscaled to the ‘Tegnùe di Chioggia’, for testing different management measures. This area, characterised by the presence of biogenic rocky outcrops and proposed as Site of Community Importance in 2011, is indeed still missing of a management plan. Trophic groups of high naturalistic and socio-economic interest have been distributed by considering different habitats and tolerance to environmental drivers. In the model, four main habitats have been defined (rocky habitat simulating the tegnùe, sandy and muddy habitats and mussel farms) and the trophic groups assigned to each one according to their preferences. Fishing activities are described considering 5 different fleets (including different trawling gears, hydraulic dredge, artisanal and recreational fishery) and their fishing effort have been spatialized based on AIS data. The tool provides output maps of group biomasses, catches, and ecosystem functioning indicators. Preliminary results are discussed in relation to their potential use for comparing the consequences of different management options (for instance the expansion of the current SCI, partial artisanal/recreational fishing openings within the SCI area, and expansion/reallocation of mussel farms and clam fishing areas)