A non-dispersive approach for a Raman gas sensor

Although Raman spectroscopy is widely used on solids and liquids, its application on gaseous samples is far less commonplace due to technical issues related to dealing with very weak signals over a strong background. A demonstration of a possible approach for a simple, noninvasive Raman-based gas detector is presented and evaluated. This setup is meant to perform nitrogen and oxygen gas concentration measurements through Raman scattering working with optical filters instead of the traditional spectrograph and a lighting-grade 532 nm diode-pumped solid state laser as the pumping source. An industrial-grade CMOS camera is used as the detector, taking full advantage of the low noise and spatial resolution of this device. The system has been tested for both oxygen and nitrogen in a gas flow cell. Nitrogen measurement in a glass vial is reported in order to demonstrate and show some of the advantages that could be obtained with the use of an imaging detector instead of a single pixel one. The reported measurements show that even without using a dispersion spectrometer, this approach enables an indicative, noninvasive gas detection through glass vials with significant rejection of the elastic scattering contribution

"Hot" Surface Activation of Molecular Complexes: Insight from Modeling Studies

Rock-and-roll over hot floors: Theoretical modeling of the first activation stages of a Cu complex on top of a heated surface (750 K) revealed two mobility regimes, a slow bump-and-rock diffusion over the surface and a fast roll-and-go motion accompanied by significant temperature-induced bond oscillations. This study enables a deeper insight into "hot" surface molecular activation processes.Tanz auf dem Vulkan: Das Modellieren der ersten Aktivierungsstufen eines Cu-Komplexes auf einer beheizten Oberfl\ue4che (750\u2005K) enth\ufcllte zwei Bewegungsarten: eine langsame Diffusion durch \u201eAnsto fen und Taumeln\u201c und eine schnelle Rollbewegung, die mit deutlichen temperaturinduzierten Bindungsoszillationen einhergeht. Diese Befunde geben einen Einblick in die Prozesse bei der Aktivierung durch \u201ehei fe\u201c Oberfl\ue4chen

A unique midgut-associated bacterial community hosted by the cave beetle \u3cem\u3eCansiliella servadeii\u3c/em\u3e (Coleoptera: Leptodirini) reveals parallel phylogenetic divergences from universal gut-specific ancestors

Background Cansiliella servadeii (Coleoptera) is an endemic troglobite living in deep carbonate caves in North-Eastern Italy. The beetle constantly moves and browses in its preferred habitat (consisting in flowing water and moonmilk, a soft speleothem colonized by microorganisms) self-preens to convey material from elytra, legs, and antennae towards the mouth. We investigated its inner and outer microbiota using microscopy and DNA-based approaches. Results Abundant microbial cell masses were observed on the external appendages. Cansiliella’s midgut is fully colonized by live microbes and culture-independent analyses yielded nearly 30 different 16S phylotypes that have no overlap with the community composition of the moonmilk. Many of the lineages, dominated by Gram positive groups, share very low similarity to database sequences. However for most cases, notwithstanding their very limited relatedness with existing records, phylotypes could be assigned to bacterial clades that had been retrieved from insect or other animals’ digestive traits. Conclusions Results suggest a history of remote separation from a common ancestor that harboured a set of gut-specific bacteria whose functions are supposedly critical for host physiology. The phylogenetic and coevolutionary implications of the parallel occurrences of these prokaryotic guilds appear to apply throughout a broad spectrum of animal diversity. Their persistence and conservation underlies a possibly critical role of precise bacterial assemblages in animal-bacteria interactions

The ASCE EUV Polarimeter

Abstract. The SOHO mission has achieved important results in the physics of solar wind and coronal mass ejection acceleration, but most of the processes that drive this acceleration have not yet been explained. The Advanced Spectroscopic and Coronagraphic Explorer (ASCE) mission will carry on-board spectroscopic and polarimetric instrumentation of new generation that is designed to address the fundamental questions on this processes. Following a brief description of ASCE scientific objectives and instrumentation, the EUV polarimetric channel is described. The EUV Polarimeter (EUVP) is designed to measure for the first time the magnetic field vector in the extended corona through the Hanle effect, and the anisotropy of the ion velocity. The EUVP represents the contribution of the Italian solar physics community to the ASCE mission

Biocontrol traits of Bacillus licheniformis GL174, a culturable endophyte of Vitis vinifera cv. Glera

Background Bacillus licheniformis GL174 is a culturable endophytic strain isolated from Vitis vinifera cultivar Glera, the grapevine mainly cultivated for the Prosecco wine production. This strain was previously demonstrated to possess some specific plant growth promoting traits but its endophytic attitude and its role in biocontrol was only partially explored. In this study, the potential biocontrol action of the strain was investigated in vitro and in vivo and, by genome sequence analyses, putative functions involved in biocontrol and plant-bacteria interaction were assessed. Results Firstly, to confirm the endophytic behavior of the strain, its ability to colonize grapevine tissues was demonstrated and its biocontrol properties were analyzed. Antagonism test results showed that the strain could reduce and inhibit the mycelium growth of diverse plant pathogens in vitro and in vivo. The strain was demonstrated to produce different molecules of the lipopeptide class; moreover, its genome was sequenced, and analysis of the sequences revealed the presence of many protein-coding genes involved in the biocontrol process, such as transporters, plant-cell lytic enzymes, siderophores and other secondary metabolites. Conclusions This step-by-step analysis shows that Bacillus licheniformis GL174 may be a good biocontrol agent candidate, and describes some distinguished traits and possible key elements involved in this process. The use of this strain could potentially help grapevine plants to cope with pathogen attacks and reduce the amount of chemicals used in the vineyard

First light observations of the solar wind in the outer corona with the Metis coronagraph

In this work, we present an investigation of the wind in the solar corona that has been initiated by observations of the resonantly scattered ultraviolet emission of the coronal plasma obtained with UVCS-SOHO, designed to measure the wind outflow speed by applying Doppler dimming diagnostics. Metis on Solar Orbiter complements the UVCS spectroscopic observations that were performed during solar activity cycle 23 by simultaneously imaging the polarized visible light and the H?» I Lyman-α corona in order to obtain high spatial and temporal resolution maps of the outward velocity of the continuously expanding solar atmosphere. The Metis observations, taken on May 15, 2020, provide the first HI Lyman-α images of the extended corona and the first instantaneous map of the speed of the coronal plasma outflows during the minimum of solar activity and allow us to identify the layer where the slow wind flow is observed. The polarized visible light (580-640 nm) and the ultraviolet HI Lyα (121.6 nm) coronal emissions, obtained with the two Metis channels, were combined in order to measure the dimming of the UV emission relative to a static corona. This effect is caused by the outward motion of the coronal plasma along the direction of incidence of the chromospheric photons on the coronal neutral hydrogen. The plasma outflow velocity was then derived as a function of the measured Doppler dimming. The static corona UV emission was simulated on the basis of the plasma electron density inferred from the polarized visible light. This study leads to the identification, in the velocity maps of the solar corona, of the high-density layer about ±10° wide, centered on the extension of a quiet equatorial streamer present at the east limb - the coronal origin of the heliospheric current sheet - where the slowest wind flows at about 160 ± 18 km s-1 from 4 R⊙ to 6 R⊙. Beyond the boundaries of the high-density layer, the wind velocity rapidly increases, marking the transition between slow and fast wind in the corona

A serious game to improve engagement with web accessibility guidelines

This is an Accepted Manuscript of an article published by Taylor & Francis in Behaviour & Information Technology on 07 Jan 2020, available online: https://www.tandfonline.com/doi/full/10.1080/0144929X.2019.171145