Observability of hydrogen-rich exospheres in Earth-like exoplanets

(Abridged) The existence of an extended neutral hydrogen exosphere around small planets can be used as an evidence for the presence of water in their lower atmosphere but, to date, such feature has not been securely detected in rocky exoplanets. Planetary exospheres can be observed using transit spectroscopy of the Lyman-$\alpha$ line, which is limited mainly by interstellar medium absorption in the core of the line, and airglow contamination from the geocorona when using low-orbit space telescopes. Our objective is to assess the detectability of the neutral hydrogen exosphere of an Earth-like planet transiting a nearby M dwarf using Lyman-$\alpha$ spectroscopy and provide the necessary strategies to inform future observations. The spatial distribution in the upper atmosphere is provided by an empirical model of the geocorona, and we assume a velocity distribution based on radiative pressure as the main driver in shaping the exosphere. We compute the excess absorption in the stellar Lyman-$\alpha$ line while in transit, and use realistic estimates of the uncertainties involved in observations to determine the observability of the signal. We found that the signal in Lyman-$\alpha$ of the exosphere of an Earth-like exoplanet transiting M dwarfs with radii between 0.1 and 0.6 R$_\odot$ produces an excess absorption between 50 and 600 ppm. The Lyman-$\alpha$ flux of stars decays exponentially with distance because of interstellar medium absorption, which is the main observability limitation. Other limits are related to the stellar radial velocity and instrumental setup. The excess absorption in Lyman-$\alpha$ is observable using LUVOIR/LUMOS in M dwarfs up to a distance of $\sim$15 pc. The analysis of noise-injected data suggests that it would be possible to detect the exosphere of an Earth-like planet transiting TRAPPIST-1 within 20 transits.Comment: 12 pages, 13 figures, accepted for publication in Astronomy & Astrophysic

Anodized aluminium pressure sensitive paint: effect of paint application technique

The porous surface of the Anodized Aluminium Pressure Sensitive Paint (AA-PSP) is what differentiates it from conventional sol–gel based PSPs, leading to a faster response time of the paint. The objective of the current study is to examine the effect of the paint application technique, i.e., whether the AA substrate is dipped or sprayed, on the pressure and temperature sensitivity. A more practical procedure for preparing the AA samples is also presented. Scanning Electron Microscope (SEM) images are acquired together with the calibration of the AA-PSP at various temperatures and pressures to determine the effectiveness of each application technique. The results revealed that the AA sample which was dipped in the PSP solution shows a higher pressure sensitivity than the sprayed one. The SEMs show that spraying leads to the covering up of the micropores created on the surface and undermining the benefit of anodization

Snow accumulation by entering low-pressures from the coast to Dome Fuji, East Antarctica

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / 2F Auditorium, National Institute of Polar Researc

Use of High Strength Steel for Hydrogen Containment

The research involves experiments on model lab heats of an ultra-high-strength steel (high C, low Ni ) and a high-toughness, high-strength steel (high Ni, low C) to determine the limits of toughness as a function of yield strength, grain-boundary purity, and hydrogen fugacity. In addition, the existence and mechanism of brittle intergranular cracking in ideally pure steels is being investigated

Ground-state electric quadrupole moment of 31Al

Ground-state electric quadrupole moment of 31Al (I =5/2+, T_1/2 = 644(25) ms) has been measured by means of the beta-NMR spectroscopy using a spin-polarized 31Al beam produced in the projectile fragmentation reaction. The obtained Q moment, |Q_exp(31Al)| = 112(32)emb, are in agreement with conventional shell model calculations within the sd valence space. Previous result on the magnetic moment also supports the validity of the sd model in this isotope, and thus it is concluded that 31Al is located outside of the island of inversion.Comment: 5 page

A case of wound dual infection with Pasteurella dagmatis and Pasteurella Canis resulting from a dog bite - limitations of Vitek-2 system in exact identification of Pasteurella species

<p>Abstract</p> <p>Background</p> <p><it>Pasteurella </it>species, widely known as indigenous orgganisms in the oral and gastrointestinal floras of many wild and domestic animals, are important pathogens in both animals and humans. Human infections due to <it>Pasteurella </it>species are in most cases associated with infected injuries following animal bites. We encountered a rare case of dual infections caused by different two <it>Pasteurella </it>species occurred in a previously healthy 25-year-old female sustaining injury by a dog-bite.</p> <p>Methodology</p> <p>Exudates from the open wound of her dog-bite site, together with the saliva of the dog were submitted for bacteriological examination. Predominantly appearing grayish-white smooth colonies with almost the same colonial properties but slightly different glistening grown on chocolate and sheep blood agar plates were characterized morphologically by Gram's stain, biochemically by automated instrument using Vitek 2 system using GN cards together with commercially available kit system, ID-Test HN-20 rapid panels, and genetically by sequencing the 16S rRNA genes of the organism using a Taq DyeDeoxy Terminator Cycle Sequencing and a model 3100 DNA sequencer instrument.</p> <p>Results</p> <p>The causative isolates from the dog-bite site were finally identified as <it>P</it>. <it>canis </it>and <it>P</it>. <it>dagmatis </it>from the findings of the morphological, cultural, and biochemical properties together with the comparative sequences of the 16S rRNA genes. Both the isolates were highly susceptible to many antibiotics and the patient was successfully treated with the administration of so-called the first generation cephalosporin, cefazolin followed by so-called the third generation cephalosporin, cefcapene pivoxil. The isolate from the dog was subsequently identified as <it>P</it>. <it>canis</it>, the same species as the isolate from the patient.</p> <p>Conclusions</p> <p>To the best of our knowledge, this was the second report of a dual infection with <it>Pasteurella </it>species consisting of <it>P</it>. <it>dagmatis </it>and <it>P. canis </it>resulting from a dog-bite, followed by the first report of dual infections due to <it>P</it>. <it>dagmatis </it>and <it>P. multocida </it>in 1988. Our isolate finally identified as <it>P</it>. <it>dagmatis </it>was misidentified as <it>P</it>. <it>pneumotripica by </it>means of the Vitek 2 system. The species name "<it>P</it>. <it>dagmatis" </it>was not included in the database of the system. It is also important for routine clinical microbiology laboratories to know the limitation of the automated Vitek 2 system for the accurate identification of <it>Pasteurella </it>species especially <it>P</it>. <it>dagmatis</it>. It should be emphasized that there still exists much room for improvement in Vitek 2 system. Significant improvement of Vitek 2 system especially in the identification of <it>Pasteurella </it>species is urgently desired.</p