Parameters of broadening of water molecule absorption lines by argon derived using different line profile models

The water vapor absorption spectrum was measured in the spectral region 6700–7650 cm–1 with argon as a buffer gas. The room-temperature spectrum was measured using a Bruker IFS 125-HR Fourier Transform Spectrometer with high signal-to-noise ratio, with a spectral resolution of 0.01 cm–1, at argon pressures from 0 to 0.9 atm. The H2O absorption spectral line parameters are derived by fitting two line shape profiles (Voigt and speed-dependent Voigt) to the experimental spectrum. It is shown that the use of speed-dependent Voigt profile provides the best agreement with experimental data

Light-emitting-diode Fourier-transform spectroscopy of HD16O between 11200 and 12400 cm-1

The absorption spectrum of monodeuterated water, HDO has been investigated between 11200 and 12400 cm-1. The spectrum has been recorded using IFS-125M interferometer with spectral resolution of 0.05 cm-1. For measurements White’s-type cell were used. The bright light emitting diode (LED) EDEI-1LS3-R was applied as a source of radiation. Signal to noise ratio was about 104. The spectral line parameters - line positions, intensities and half-widths were obtained by least square fitting. As a result of the spectrum analysis the line list containing more than 1500 lines was created. The spectral line parameters have been compared with the previous measured and calculated data. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Intensity-dependent reflectance modulation of femtosecond laser pulses in GaAs nanocylinders with magnetic resonances

Abstract We experimentally demonstrate modulation of reflectance in periodic arrays of subwavelength gallium arsenide nanocylinders with Mie-type resonances due to absorption saturation and changes in the refractive index of the semiconductor material of metasurface. The intensity-dependent reflectance modulation of up to 30% in the vicinity of the magnetic dipole resonance at a low laser fluence below 200 μ J/cm 2 is shown by I-scan measurements

Molecular epidemiology, phylogeny, and phylodynamics of CRF63_02A1, a recently originated HIV-1 circulating recombinant form spreading in Siberia

The HIV-1 epidemic in Russia is dominated by the former Soviet Union subtype A (A(FSU)) variant, but other genetic forms are circulating in the country. One is the recently described CRF63_02A1, derived from recombination between a CRF02_AG variant circulating in Central Asia and A(FSU), which has spread in the Novosibirsk region, Siberia. Here we phylogenetically analyze pol and env segments from 24 HIV-1 samples from the Novosibirsk region collected in 2013, with characterization of three new near full-length genome CRF63_02A1 sequences, and estimate the time of the most recent common ancestor (tMRCA) and the demographic growth of CRF63_02A1 using a Bayesian method. The analyses revealed that CRF63_02A1 is highly predominant in the Novosibirsk region (81.2% in pol sequences) and is transmitted both among injecting drug users and by heterosexual contact. Similarity searches with database sequences combined with phylogenetic analyses show that CRF63_02A1 is circulating in East Kazakhstan and the Eastern area of Russia bordering China. The analyses of near full-length genome sequences show that its mosaic structure is more complex than reported, with 18 breakpoints. The tMRCA of CRF63_02A1 was estimated around 2006, with exponential growth in 2008-2009 and subsequent stabilization. These results provide new insights into the molecular epidemiology, phylogeny, and phylodynamics of CRF63_02A1.We thank the personnel at the Genomic Unit of Instituto de Salud Carlos III, Majadahonda, Madrid, Spain, for technical assistance in sequencing, and Bonnie Mathieson, from the Office of AIDS Research, National Institutes of Health, Bethesda, Maryland for her support of this study. This work was funded by Office of AIDS Research, National Institutes of Health, through the training program “Molecular Epidemiology of HIV-1 in Eastern Europe and Its Significance for Vaccine Development.”S

Star Formation and Dynamics in the Galactic Centre

The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A., 'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

Scientific rationale for Uranus and Neptune <i>in situ</i> explorations

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission

New Tools for Structural Biology and Biophysics: High-Throughput Fluorine Solid-State NMR and Applications to Membrane Proteins

Solid-State Nuclear Magnetic Resonance (SSNMR) spectroscopy is a powerful method for characterizing the structure and dynamics of crystalline and amorphous solid compounds, materials, and biological systems. When applied to biomolecular systems such as membrane proteins, it can provide access to information about structure and dynamics in native environments, on targets that are difficult to characterize by other biophysical methods. Membrane proteins in particular are critical for biological function and are overrepresented as drug targets; however, they are notoriously difficult to study. In this thesis, new SSNMR methods are developed, utilizing fast Magic Angle Spinning (MAS), multidimensional correlation, and the 19F nucleus as a biophysical probe for the understanding the structure and dynamics of crystalline and membrane-bound proteins and protein-ligand complexes. Internuclear distances are critical in biomolecular structure determination. The 19F nucleus, due to its high gyromagnetic ratio, absence of natural background, small atomic radius, and highly developed chemistry is uniquely suited as a probe for measuring long internuclear distances. Utilizing uniform 13C labeling and multidimensional correlation, an experiment for multiplex measurement of 13C-19F distances is developed. Furthermore, 13C-19F coherence transfer methods are compared and optimized to enable direct 13C-19F correlation to disambiguate constraints in polyfluorinated systems. These technological developments are applied toward determining the structure of the Envelope (E) protein of the novel SARS CoV-2 virus. With fast MAS, proton-detected experiments in SSNMR are possible with high resolution and sensitivity. A new method for measuring nanometer-length distances in a multiplex manner is developed, utilizing 1H-19F Rotational Echo Double Resonance (REDOR) and two-dimensional 1H-15N correlation. The experiment is developed on a quad-labeled (uniform 2H, 13C, 15N, and 19F-tagged) model protein, and the distances measured are shown to be in quantitative agreement with the known structure. This technology is applied to refine the structure of the E. coli. multidrug resistance protein E (EmrE), by measuring a large number of 1H-19F distances between a tetrafluorinated ligand and the protein HN atoms. The structure of the EmrE protein was determined at high and low pH, modeling functional states of the transporter, and providing insight into the mechanism of the proton-coupled antiport.Ph.D