A practical approach to the production of ENC with high density bathymetric content

Over the last two years, the Australian Hydrographic Office (AHO) has published and maintained Electronic Navigational Charts (ENC) with greater scale and higher density bathymetric content than those derived from paper nautical charts. Land Information New Zealand (LINZ) is investigating the production of ENCs with high density bathymetric content which will likely replace the traditional berthing ENC. This article describes the approaches adopted by AHO and LINZ to produce such ENC using current IHO standards. The article describes also how AHO and LINZ engaged with stakeholders to meet the demands of large ships navigating in confined waters with small safety margins. ENCs with greater scale and high density-bathymetric content represent an opportunity for Hydrographic Offices to not only enhance safety of navigation under normal circumstances in confined waters, but also to potentially expand the range of weather and tidal conditions in which safe navigation may be conducted.En los dos últimos años, el Servicio Hidrográfico Australiano (AHO) ha publicado y mantenido Cartas Náuticas Electrónicas (ENCs) de mayor escala y con un contenido batimétrico de mayor densidad que las derivadas de las cartas náuticas de papel. Land Information New Zealand (LINZ) está investigando la producción de ENCs con un contenido batimétrico de alta densidad, que probablemente sustituirán a las tradicionales ENCs de las zonas de atraque. Este artículo describe los enfoques adoptados por el AHO y por LINZ para producir tales ENCs utilizando las normas actuales de la OHI. Este artículo también describe cómo el AHO y LINZ se comprometieron con las partes interesadas para satisfacer las demandas de los grandes buques que navegan en aguas confinadas con pequeños márgenes de seguridad. Las ENCs de mayor escala y de contenido batimétrico de alta densidad representan una oportunidad para que los Servicios Hidrográficos no sólo mejoren la seguridad de la navegación en circunstancias normales en aguas confinadas, sino que también amplíen potencialmente la variedad de condiciones meteorológicas y de mareas en las que se puede llevar a cabo una navegación segura.Ces deux dernières années, le Service hydrographique australien (AHO) a publié et tenu à jour des cartes électroniques de navigation (ENC) à plus grandes échelles et contenant des données bathymétriques à plus haute densité que celles issues des cartes marines papier. Le Land Information New Zealand (LINZ) étudie la production d’ENC contenant des données bathymétriques à haute densité, qui remplaceront sûrement les traditionnelles ENC d’accostage. Le présent article décrit l’approche adoptée par l’AHO et le LINZ pour produire ces ENC en utilisant les normes de l’OHI en vigueur. L’article décrit également la manière dont l’AHO et le LINZ se sont impliqués auprès des parties prenantes afin de répondre aux contraintes des navires de grande taille qui naviguent dans des eaux resserrées avec de faibles marges de sécurité. Des ENC contenant des données à plus grandes échelles et des données bathymétriques à haute densité représentent l’opportunité pour les services hydrographiques non seulement d’améliorer la sécurité de la navigation dans des eaux resserrées dans des circonstances normales, mais également d’étendre potentiellement l’éventail des conditions météorologiques et de marées dans lesquelles il est possible de naviguer en toute sécurité

Laser induced fluorescence for axion dark matter detection: a feasibility study in YLiF4_4:Er3+^{3+}

We present a detection scheme to search for QCD axion dark matter, that is based on a direct interaction between axions and electrons explicitly predicted by DFSZ axion models. The local axion dark matter field shall drive transitions between Zeeman-split atomic levels separated by the axion rest mass energy $m_a c^2$. Axion-related excitations are then detected with an upconversion scheme involving a pump laser that converts the absorbed axion energy ($\sim$ hundreds of $\mu$eV) to visible or infrared photons, where single photon detection is an established technique. The proposed scheme involves rare-earth ions doped into solid-state crystalline materials, and the optical transitions take place between energy levels of $4f^N$ electron configuration. Beyond discussing theoretical aspects and requirements to achieve a cosmologically relevant sensitivity, especially in terms of spectroscopic material properties, we experimentally investigate backgrounds due to the pump laser at temperatures in the range $1.9-4.2$ K. Our results rule out excitation of the upper Zeeman component of the ground state by laser-related heating effects, and are of some help in optimizing activated material parameters to suppress the multiphonon-assisted Stokes fluorescence.Comment: 8 pages, 5 figure

Diode-pumped passively mode-locked Yb:YLF laser.

We demonstrate passive mode-locking by means of a semiconductor saturable-absorber mirror in a diode-pumped Yb:YLF laser. We present crystal growth process, spectroscopic measurements, and investigation of mode-locking performance. Pulse trains with minimum duration of 196 fs, average power of 54 mW and a repetition rate of 55 MHz were obtained. The optical spectrum, centered at 1028 nm, has a 7.1-nm bandwidth leading to nearly transform-limited pulses. (C) 2008 Optical Society of America

Efficient visible laser emission of GaN laser diode pumped Pr-doped fluoride scheelite crystals.

In the present work we report on the growth, spectroscopy and laser results of diode pumped Pr-doped LiYF4, LiLuF4 and LiGdF4 fluoride, scheelite-type structure crystals. We measured the polarisation dependent absorption and emission properties as well as the decay time of the P-3(0) level. Exploiting the P-3(2) absorption around 444 nm, we obtained efficient laser emission under GaN laser diode pumping on several transitions from the green to the near infrared wavelength range. (C) 2008 Optical Society of Americ

Particle detection through the quantum counter concept in YAG:Er3+^{3+}

We report about a novel scheme for particle detection based on the infrared quantum counter concept. Its operation consists of a two-step excitation process of a four level system, that can be realized in rare earth-doped crystals when a cw pump laser is tuned to the transition from the second to the fourth level. The incident particle raises the atoms of the active material into a low lying, metastable energy state, triggering the absorption of the pump laser to a higher level. Following a rapid non-radiative decay to a fluorescent level, an optical signal is observed with a conventional detectors. In order to demonstrate the feasibility of such a scheme, we have investigated the emission from the fluorescent level $^4$S$_{3/2}$ (540 nm band) in an Er$^{3+}$-doped YAG crystal pumped by a tunable titanium sapphire laser when it is irradiated with 60 keV electrons delivered by an electron gun. We have obtained a clear signature this excitation increases the $^{4}I_{13/2}$ metastable level population that can efficiently be exploited to generate a detectable optical signal

Integrated network analysis reveals new genes suggesting COVID-19 chronic effects and treatment

The COVID-19 disease led to an unprecedented health emergency, still ongoing worldwide. Given the lack of a vaccine or a clear therapeutic strategy to counteract the infection as well as its secondary effects, there is currently a pressing need to generate new insights into the SARS-CoV-2 induced host response. Biomedical data can help to investigate new aspects of the COVID-19 pathogenesis, but source heterogeneity represents a major drawback and limitation. In this work, we applied data integration methods to develop a Unified Knowledge Space (UKS) and used it to identify a new set of genes associated with SARS-CoV-2 host response, both in vitro and in vivo. Functional analysis of these genes reveals possible long-term systemic effects of the infection, such as vascular remodelling and fibrosis. Finally, we identified a set of potentially relevant drugs targeting proteins involved in multiple steps of the host response to the virus.Peer reviewe

Eye-Safe Solid-State Quasi-CW Raman Laser with Millisecond Pulse Duration

We demonstrate the first quasi-CW (ms-long pulses, pump duty cycle of 10%) end-diode pumped solid state laser generating eye-safe radiation via intracavity Raman conversion. The output power at the first Stokes wavelength (1524 nm) was 250 mW. A theoretical model was applied to analyze the laser system and provide routes for optimization. The possibility of true CW operation was discussed.Comment: Preprint accepted for publication in Optics Communications on Feb 6, 201

Characterization of Strombolian events by using independent component analysis

We apply Independent Component Analysis (ICA) to seismic signals recorded at Stromboli volcano. Firstly, we show how ICA works considering synthetic signals, which are generated by dynamical systems. We prove that Strombolian signals, both tremor and explosions, in the high frequency band (>0.5 Hz), are similar in time domain. This seems to give some insights to the organ pipe model generation for the source of these events. Moreover, we are able to recognize in the tremor signals a low frequency component (<0.5 Hz), with a well defined peak corresponding to 30s