86 research outputs found
Detection of the spectral binary (SB2) nature of BD-6^o1178
BD-6^o1178 identified with the infrared source IRAS05238-0626 is shown for
the first time to be a spectroscopic binary (SB2) by analyzing the
high-resolution spectra taken with the NES echelle spectrograph of the 6-m
telescope. The components of the binary have close spectral types and
luminosity classes: F5IV-III and F3V. The heliocentric radial velocities are
measured for both components at four observing moments in 2004-2005. Both stars
have close rotation velocities, which are equal to 24 and 19km/s. We do not
confirm the classification of BD-6^o1178 as a supergiant in the transition
stage of becoming a planetary nebula. BD-6^o1178 probably is a young pre-MS
stars. It is possibly a member of the 1c subgroup of the OriOB1 association.Comment: 13 pages, 1 table, 4 figure
Shibusawa Eiichi\u27s View of Japan\u27s Foreign Affairs: Focusing on His Influences on the Meiji Government
From the mid-nineteenth century, Asia, including China and Japan, has been involved in the trend of modernization that was triggered by the activities of European and American powers in this area. In a time of drastic changes, Shibusawa Eiichi (1840-1931) assumed several roles successively: he served as retainer during the bakumatsu period, as official in the Meiji government, and afterwards as businessman, philanthropist, and non-official diplomat. During his service in the Meiji government from 1869 to 1873 and as an entrepreneur from 1873 to 1909, Shibusawa played a key role in devising economic and diplomatic policies for the Meiji government. He is even considered a major designer of modem Japanese economic systems and society. This paper examines Shibusawa Eiichi\u27s view of Japan\u27s foreign affairs and focuses on the way he influenced the Meiji government
V2324Cyg - an F-type star with fast wind
For the first time high-resolution optical spectroscopy of the variable star
V2324Cyg associated with the IR-source IRAS20572+4919 is made. More than 200
absorption features (mostly FeII, TiII, CrII, YII, BaII, and YII) are
identified within the wavelength interval 4549-7880AA. The spectral type and
rotation velocity of the star are found to be F0III and Vsini=69km/s,
respectively. HI and NaID lines have complex PCyg-type profiles with an
emission component. Neither systematic trend of radial velocity Vr with line
depth Ro nor temporal variability of Vr have been found. We determined the
average heliocentric radial velocity Vr=-16.8\pm 0.6km/s. The radial velocities
inferred from the cores of the absorption components of the H and NaI
wind lines vary from -140 to -225km/s (and the expansion velocities of the
corresponding layers, from about 120 to 210km/s). The maximum expansion
velocity is found for the blue component of the split H absorption:
450km/s for December 12, 1995. The model atmospheres method is used to
determine the star's parameters: Teff=7500K, log g=2.0, =6.0km/s, and
metallicity, which is equal to the solar value. The main peculiarity of the
chemical abundances pattern is the overabundance of lithium and sodium. The
results cast some doubt on the classification of V2324Cyg as a post-AGB star.Comment: 28 pages, 6 figure
The multistatutory nature of the adjective "Right" in adjectival English lexicon
This article provides an outline on an adjective in modern English language, and in particular, the multistatus lexical item “right”, which carries different meanings in different variants of combinatorics. The authors analyse the combinations used with the adjectival lexical item “right” and identify categories that determine the semantic content of each given statemen
Oligomerization of the antimicrobial peptide Protegrin-5 in a membrane-mimicking environment. Structural studies by high-resolution NMR spectroscopy
© 2016 European Biophysical Societies' AssociationProtegrin pore formation is believed to occur in a stepwise fashion that begins with a nonspecific peptide interaction with the negatively charged bacterial cell walls via hydrophobic and positively charged amphipathic surfaces. There are five known nature protegrins (PG1-PG5), and early studies of PG-1 (PDB ID:1PG1) shown that it could form antiparallel dimer in membrane mimicking environment which could be a first step for further oligomeric membrane pore formation. Later, we solved PG-2 (PDB ID:2MUH) and PG-3 (PDB ID:2MZ6) structures in the same environment and for PG-3 observed a strong dαα NOE effects between residues R18 and F12, V14, and V16. These “inconsistent” with monomer structure NOEs appears due to formation of an additional antiparallel β-sheet between two monomers. It was also suggested that there is a possible association of protegrins dimers to form octameric or decameric β-barrels in an oligomer state. In order to investigate a more detailed oligomerization process of protegrins, in the present article we report the monomer (PDB ID: 2NC7) and octamer pore structures of the protegrin-5 (PG-5) in the presence of DPC micelles studied by solution NMR spectroscopy. In contrast to PG-1, PG-2, and PG-3 studies, for PG-5 we observed not only dimer NOEs but also several additional NOEs between side chains, which allows us to calculate an octamer pore structure of PG-5 that was in good agreement with previous AFM and PMF data
Antimicrobial peptide protegrin-3 adopt an antiparallel dimer in the presence of DPC micelles: A high-resolution NMR study
© 2015 Springer Science+Business Media Dordrecht. A tendency to dimerize in the presence of lipids was found for the protegrin. The dimer formation by the protegrin-1 (PG-1) is the first step for further oligomeric membrane pore formation. Generally there are two distinct model of PG-1 dimerization in either a parallel or antiparallel β-sheet. But despite the wealth of data available today, protegrin dimer structure and pore formation is still not completely understood. In order to investigate a more detailed dimerization process of PG-1 and if it will be the same for another type of protegrins, in this work we used a high-resolution NMR spectroscopy for structure determination of protegrin-3 (RGGGL-CYCRR-RFCVC-VGR) in the presence of perdeuterated DPC micelles and demonstrate that PG-3 forms an antiparallel NCCN dimer with a possible association of these dimers. This structural study complements previously published solution, solid state and computational studies of PG-1 in various environments and validate the potential of mean force simulations of PG-1 dimers and association of dimers to form octameric or decameric β-barrels
Testing Rotational Mixing Predictions with New Boron Abundances in Main Sequence B-type Stars
(Abridged) New boron abundances for seven main-sequence B-type stars are
determined from HST STIS spectroscopy around the BIII 2066A line. Boron
abundances provide a unique and critical test of stellar evolution models that
include rotational mixing since boron is destroyed in the surface layers of
stars through shallow mixing long before other elements are mixed from the
stellar interior through deep mixing. Boron abundances range from 12+log(B/H) =
1.0 to 2.2. The boron abundances are compared to the published values of their
stellar nitrogen abundances (all have 12+log(N/H) < 7.8, i.e., they do not show
significant CNO-mixing) and to their host cluster ages (4 to 16 Myr) to
investigate the predictions from models of massive star evolution with
rotational mixing effects (Heger & Langer 2000). Only three stars (out of 34)
deviate from the model predictions, including HD36591, HD205021, and HD30836.
These three stars suggest that rotational mixing could be more efficient than
currently modelled at the highest rotation rates.Comment: 10 figures, 7 tables; accepted for publication in the Astrophysical
Journa
A search for diffuse bands in the circumstellar envelopes of post-AGB stars
In this work we present the results of a systematic search for diffuse bands
(DBs, hereafter) in the circumstellar envelopes of a carefully selected sample
of post-AGB stars. We concentrated on the analysis of 9 of the DBs most
commonly found in the interstellar medium. The strength of these features is
determined using high resolution optical spectroscopy and the results obtained
are compared with literature data on field stars affected only by interstellar
reddening. Based on the weak features observed in the subsample of post-AGB
stars dominated by circumstellar reddening we conclude that the carrier(s) of
these DBs must not be present in the circumstellar environment of these
sources, or at least not under the excitation conditions in which DBs are
formed. The conclusion is applicable to all the post-AGB stars studied,
irrespective of the dominant chemistry or the spectral type of the star
considered. A detailed radial velocity analysis of the features observed in
individual sources confirms this result, as the Doppler shifts measured are
found to be consistent with an interstellar origin.Comment: Accepted for A&
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