MULTI-CAMERA SYSTEM CALIBRATION OF A LOW-COST REMOTELY OPERATED VEHICLE FOR UNDERWATER CAVE EXPLORATION

Exploration, documentation and mapping of underwater environment is one of the biggest open challenges for science and engineering. Humankind is not naturally designed to operate in water and, despite the enormous technological advancement that offers nowadays unprecedented opportunities, diving and working underwater is still very dangerous, especially in confined spaces such as underwater caves. Great research efforts are currently devoted to underwater autonomous navigation, but available solutions still mainly rely on complex and expensive systems, due to the difficulty of adapting localization and mapping sensors and algorithms suited for terrestrial or aerial applications. However, small and affordable underwater remotely operated vehicles (ROVs) are available, which offer good opportunities for underwater exploration and mapping. This paper focuses on the development of a small, low-cost ROV designed for 3D mapping of underwater environments, like caves. The system is based on a commercially available vehicle, the BluRov2, and relies on the use of up to 12 action cameras (GoPro) mounted on it. A trifocal camera system for underwater real-time visual odometry can also be included. The work describes the photogrammetric procedure developed for the synchronization and calibration of the GoPro cameras and provides a thorough analysis on the achievable results

Relative cost-effectiveness of an extensively hydrolyzed casein formula containing the probiotic Lactobacillus rhamnosus GG in managing infants with cow’s milk allergy in Italy

Objective: To estimate the cost-effectiveness of using an extensively hydrolyzed casein formula (eHCF) containing the probiotic Lactobacillus rhamnosus GG, (eHCF + LGG; Nutramigen LGG) as first-line management for cow’s milk allergy (CMA) compared with eHCF alone, soy-based formulae (SBF), hydrolyzed rice formulae (HRF), and amino acid formulae (AAF) in Italy, from the perspective of the Italian National Health Service (INHS) and parents. Methods: Decision modeling was used to estimate the probability of infants developing tolerance to cow’s milk by 18 months, based on an observational study dataset. The model also estimated the cost (at 2012/2013 prices) of health care resource use funded by the INHS and formulae paid for by parents over 18 months after starting a formula, as well as the relative cost-effectiveness of each of the formulae. Results: The probability of developing tolerance to cow’s milk by 18 months was higher among infants with either IgE-mediated or non-IgE-mediated allergy who were fed eHCF + LGG compared to those fed one of the other formulae. The total health care cost of initially feeding infants with eHCF + LGG was less than that of feeding infants with one of the other formulae. Hence, eHCF + LGG affords the greatest value for money to both the INHS and parents of infants with either IgE-mediated or non-IgE-mediated CMA. Conclusion: Using eHCF + LGG instead of eHCF, SBF, HRF, or an AAF for first-line management of newly diagnosed infants with CMA in Italy affords a cost-effective use of publicly funded resources, and is cost-effective from the parents’ perspective, since it improves outcome for less cost. A randomized controlled study showing faster tolerance development in children receiving a probiotic-containing formula is required before this conclusion can be confirmed

EVALUATION OF VISION-BASED LOCALIZATION AND MAPPING TECHNIQUES IN A SUBSEA METROLOGY SCENARIO

Metrology is fundamental in all the applications that require to qualify, verify and validate measured data according to standards or, in other words, to assess their compliance with predefined tolerances. At sea, metrology is commonly associated with the process of measuring underwater structures, mainly pipeline elements widely used in offshore industry. Subsea operations are very expensive; optimizing time and money resources are the core factors driving innovation in the subsea metrology industry. In this study, the authors investigate the use of state-of-art vision-based algorithms, i.e. ORB-SLAM2 and Visual Odometry, as a navigation tool to assist and control a Remotely Operated Vehicle (ROV) while performing subsea metrology operations. In particular, the manuscript will focus on methods for assessing the accuracy of both trajectory and tie points provided by the tested approaches and evaluating whether the preliminary real time reconstruction meets the tolerances defined in typical subsea metrology scenarios

Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates

We present a soft x-ray angle-resolved photoemission spectroscopy study of the overdoped high-temperature superconductors La$_{2-x}$Sr$_x$CuO$_4$ and La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No $k_z$ dispersion is observed along the nodal direction, whereas a significant antinodal $k_z$ dispersion is identified. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van-Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La$_{2-x}$Sr$_x$CuO$_4$ can not be assigned to the van-Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat

ONTOLOGY-BASED WEB TOOLS for RETRIEVING PHOTOGRAMMETRIC CULTURAL HERITAGE MODELS

International audienc

USING VIRTUAL OR AUGMENTED REALITY for the TIME-BASED STUDY of COMPLEX UNDERWATER ARCHAEOLOGICAL EXCAVATIONS

International audienceCultural Heritage (CH) resources are partial, heterogeneous, discontinuous, and subject to ongoing updates and revisions. The use of semantic web technologies associated with 3D graphical tools is proposed to improve access, exploration, exploitation and enrichment of these CH data in a standardized and more structured form. This article presents the monitoring work developed for more than ten years on the excavation of the Xlendi site. Around an exceptional shipwreck, the oldest from the Archaic period in the Western Mediterranean, we have set up a unique excavation at a depth of 110m assisted by a rigorous and continuous photogrammetry campaign. All the collected results are modelled by an ontology and visualized with virtual and augmented reality tools that allow a bidirectional link between the proposed graphical representations and the non-graphical archaeological data. It is also important to highlight the development of an innovative 3D mobile app that lets users study and understand the site as well as experience sensations close to those of a diver visiting the site

Neutron powder diffraction study of NaMn2_2O4_4 and Li0.92_{0.92}Mn2_2O4_4: New insights on spin-charge-orbital ordering

The high-pressure synthesized quasi-one-dimensional compounds NaMn$_2$O$_4$ and Li$_{0.92}$Mn$_2$O$_4$ are both antiferromagnetic insulators, and here their atomic and magnetic structures were investigated using neutron powder diffraction. The present crystal structural analyses of NaMn2O4 reveal that Mn3+/Mn4+ charge-ordering state exist even at low temperature (down to 1.5 K). It is evident from one of the Mn sites shows a strongly distorted Mn3+ octahedra due to the Jahn-Teller effect. Above TN = 39 K, a two-dimensional short-range correlation is observed, as indicated by an asymmetric diffuse scattering. Below TN, two antiferromagnetic transitions are observed (i) a commensurate long-range Mn3+ spin ordering below 39 K, and (ii) an incommensurate Mn4+ spin ordering below 10 K. The commensurate magnetic structure (kC = 0.5, -0.5, 0.5) follows the magnetic anisotropy of the local easy axes of Mn3+, while the incommensurate one shows a spin-density-wave order with kIC = (0,0,0.216). For Li$_{0.92}$Mn$_2$O$_4$, on the other hand, absence of a long-range spin ordered state down to 1.5 K is confirmed.Comment: 11 pages, 8 figure

Quantifying the Loss of Coral from a Bleaching Event Using Underwater Photogrammetry and AI-Assisted Image Segmentation

Detecting the impacts of natural and anthropogenic disturbances that cause declines in organisms or changes in community composition has long been a focus of ecology. However, a tradeoff often exists between the spatial extent over which relevant data can be collected, and the resolution of those data. Recent advances in underwater photogrammetry, as well as computer vision and machine learning tools that employ artificial intelligence (AI), offer potential solutions with which to resolve this tradeoff. Here, we coupled a rigorous photogrammetric survey method with novel AI-assisted image segmentation software in order to quantify the impact of a coral bleaching event on a tropical reef, both at an ecologically meaningful spatial scale and with high spatial resolution. In addition to outlining our workflow, we highlight three key results: (1) dramatic changes in the three-dimensional surface areas of live and dead coral, as well as the ratio of live to dead colonies before and after bleaching; (2) a size-dependent pattern of mortality in bleached corals, where the largest corals were disproportionately affected, and (3) a significantly greater decline in the surface area of live coral, as revealed by our approximation of the 3D shape compared to the more standard planar area (2D) approach. The technique of photogrammetry allows us to turn 2D images into approximate 3D models in a flexible and efficient way. Increasing the resolution, accuracy, spatial extent, and efficiency with which we can quantify effects of disturbances will improve our ability to understand the ecological consequences that cascade from small to large scales, as well as allow more informed decisions to be made regarding the mitigation of undesired impacts

Immunocluster provides a computational framework for the nonspecialist to profile high-dimensional cytometry data

High-dimensional cytometry is an innovative tool for immune monitoring in health and disease, and it has provided novel insight into the underlying biology as well as biomarkers for a variety of diseases. However, the analysis of large multiparametric datasets usually requires specialist computational knowledge. Here, we describe ImmunoCluster (https://github.com/ kordastilab/ImmunoCluster), an R package for immune profiling cellular heterogeneity in highdimensional liquid and imaging mass cytometry, and flow cytometry data, designed to facilitate computational analysis by a nonspecialist. The analysis framework implemented within ImmunoCluster is readily scalable to millions of cells and provides a variety of visualization and analytical approaches, as well as a rich array of plotting tools that can be tailored to users’ needs. The protocol consists of three core computational stages: (1) data import and quality control; (2) dimensionality reduction and unsupervised clustering; and (3) annotation and differential testing, all contained within an R-based open-source framework

Magnetism and Ion Diffusion in Honeycomb Layered Oxide K2_2Ni2_2TeO6_6: First Time Study by Muon Spin Rotation & Neutron Scattering

In the quest of finding novel and efficient batteries, a great interest has raised in K-based honeycomb layer oxide materials both for their fundamental properties and potential applications. A key issue in the realization of efficient batteries based on such compounds, is to understand the K-ion diffusion mechanism. However, investigation of potassium-ion (K$^+$) dynamics in materials using magneto-spin properties has so far been challenging, due to its inherently weak nuclear magnetic moment, in contrast to other alkali ions such as lithium and sodium. Spin-polarised muons, having a high gyromagnetic ratio, make the muon spin rotation and relaxation ($\mu$+SR) technique ideal for probing ions dynamics in weak magneto-spin moment materials. Here we report the magnetic properties and K+ dynamics in honeycomb layered oxide material of the K$_2$Ni$_2$TeO$_6$ using $\mu$+SR measurements. Our low-temperature $\mu$+SR results together with, with complementary magnetic susceptibility, find an antiferromagnetic transition at 26 K. Further $\mu$+SR studies performed at higher temperatures reveal that potassium ions (K$^+$) become mobile above 250 K and the activation energy for the diffusion process is Ea = 121(13) meV. This is the first time that K+ dynamics in potassium-based battery materials has been measured using $\mu$+SR. Finally our results also indicate an interesting possibility that K-ion self diffusion occurs predominantly at the surface of the powder particles. This opens future possibilities for improving ion diffusion and device performance using nano-structuring.Comment: 12 pages, 12 figure