1,722,371 research outputs found
The light curve and evolutionary status of the carbon star V Hya
No full text. V Hya, an evolved carbon star with a complex circumstellar envelope, has two variability periods, 530 d and 6000 d (17 years). We analyze recent light curve data and show that both variations have been present for at least 100 years and have been regular over this time. The 530 d period and its 1:5 m \Gamma 2 m amplitude show that V Hya is a Mira variable. We suggest that the star is in a binary system (as also suspected from the structure of the circumstellar envelope) and that the 17-year variation is due to extinction by circumstellar dust orbiting with the companion. The properties of the envelope found from molecular line observations: the fast molecular wind, the relatively small size of the dense circumstellar envelope, and the high mass loss rate, all suggest that V Hya has entered its `superwind' phase. However, its spectral type, period, colors, and lack of ionizing radiation show that the star is still on the AGB. These properties add to the evidence that the com..
Vascular network formation in HyA matrix.
No full textExpression of CD31 after 14 days of encapsulation of hCDC in (A) HyA (B) HyA-TGF-β1 and (C) HyA-TGF-β1/CD105 Ab. (D) Quantification of the length of CD31+ structures reveals a significant effect of TGF-β1 on the formation of CD31+ networks. Data represents mean ± SD (n = 3). Analysis performed using one-way ANOVA, p < 0.05. * denotes statistical significance. Scale Bar = 100 μm.</p
Survival of hCDC 24 hours after encapsulation in HyA hydrogels.
No full textLive/Dead staining of matrices (A) HyA, (B) HyA-TGF-β1 and (C) HyA-TGF-β1/CD105 Ab blocking. Scale Bar = 100 μm.</p
Zum altpersischen Hya
No full textDans cet article, l'auteur fait une étude du pronom relatif vieux-perse hya. Surtout la prononciation ancienne de ce pronom est discutée
RADIAL STRUCTURE IN THE TW Hya CIRCUMSTELLAR DISK
No full textWe present new near-infrared interferometric data from the CHARA array and the Keck Interferometer on the circumstellar disk of the young star, TW Hya, a proposed "transition disk." We use these data, as well as previously published, spatially resolved data at 10 μm and 7 mm, to constrain disk models based on a standard flared disk structure. We find that we can match the interferometry data sets and the overall spectral energy distribution with a three-component model, which combines elements at spatial scales proposed by previous studies: optically thin, emission nearest the star, an inner optically thick ring of emission at roughly 0.5 AU followed by an opacity gap and, finally, an outer optically thick disk starting at ~4 AU. The model demonstrates that the constraints imposed by the spatially resolved data can be met with a physically plausible disk but this requires a disk containing not only an inner gap in the optically thick disk as previously suggested, but also a gap between the inner and outer optically thick disks. Our model is consistent with the suggestion by Calvet et al. of a planet with an orbital radius of a few AU. We discuss the implications of an opacity gap within the optically thick disk
Period changes of two contact binaries: DF Hya and WZ And
No full text33rd International Physics Congress of the Turkish-Physical-Society (TPS) -- SEP 06-10, 2017 -- Bodrum, TURKEYOrbital period variations of two contact binaries DF Hya and WZ And are analyzed with the least-squares method by using all available minima times. It is shown that the period variations of these systems are due mainly to the LightTime Effect (LITE) due originates from gravitational influence of a third body. New LITE elements such as, orbital periods and minimum masses of possibility third bodies are given.Turkish Phys So
Spreading of hCDC to HyA matrices after 3 days.
No full textActin stain of hCDC encapsulated in (A) HyA, (B) HyA-TGF-β1 and (C) HyA-TGF-β1/CD105 Ab blocking. (D) Quantification of cell area shows that TGF-β1 significantly enhances the spreading of hCDC, but that this effect can be abrogated by pre-incubation with CD105 antibody. Data represents mean ± SD (n = 3). Analysis performed using one-way ANOVA, p < 0.05. * denotes statistical significance. Scale Bar = 100 μm.</p
UVIT/AstroSat observation of TW Hya
No full textThe paper demonstrates the spectroscopic and photometric capabilities of the
Ultra-Violet Imaging Telescope (UVIT) to study T-Tauri stars (TTSs). We present
the first UVIT/Far-UV spectrum of a TTS, TW Hya. Based on C IV line luminosity,
we estimated accretion luminosity (0.1 ) and mass accretion rate (2.2
) of TW Hya, and compared these values with the
accretion luminosity (0.03 ) and mass accretion rate (0.6
) derived from spectral energy distribution (SED). From
the SED, we derive best-fitted parameters for TW Hya: = 390050
K, radius = 1.20.03 , and equivalent
black-body temperatures corresponding to accretion luminosity as 1410025
K. The parameters of TW Hya derived from UVIT observations were found to be
matched well with the literature. Comparison with IUE spectra also suggests
that UVIT can be used to study the spectroscopic variability of young stars.
This study proposes leveraging the FUV spectroscopic capabilities of UVIT to
contribute to the advancement of upcoming UV spectroscopic missions, including
the Indian Spectroscopic Imaging Space Telescope (INSIST).Comment: 9 pages, 3 figures, 2 table
YY Hya and its interstellar environment
No full textContext. During a search for previously unknown Galactic emission nebulae, we discovered a faint 36′ diameter Hα emission nebula centered around the periodic variable YY Hya. Although this star has been classified as an RR-Lyr variable, such a classification is inconsistent with a Gaia distance of ≃450 pc. The GALEX image data also show YY Hya as having a strong UV excess, suggesting the existence of a hot and compact binary companion.
Aims. We aim to clarify the nature of YY Hya and its nebula.
Methods. In addition to our discovery image data, we obtained a 2.°5 × 2.°5 image mosaic of the whole region with CHILESCOPE facilities and time-series spectroscopy at MDM observatory. Also, we used data from various space missions to derive an exact orbital period and a spectral energy distribution.
Results. We find that YY Hya is a compact binary system containing a K dwarf star that is strongly irradiated by a hot white dwarf companion. The spectral characteristics of the emission lines that are visible only during the maximum light of the perfectly sinusoidal optical light curve show signatures resembling those of members of the BE UMa variable family. These are post-common-envelope pre-cataclysmic variables. However, the companion star here is more massive than that found in other group members and, thus, the progenitor of the white dwarf must have been a star between 3 and 4 M⊙. The nebula appears to be an ejected common-envelope shell with a mass on the order of one M⊙ and an age of 500 000 yr. This makes it the biggest such shell known thus far. The alignment of neighboring nebulosities some 45′ to the northeast and southwest of YY Hya suggests that the system has had strong bipolar outflows. We also briefly speculate that it might be related to the 1065 BP “guest-star” reported in ancient Chinese records
A Gut Microbial Metabolite HYA Ameliorates Adipocyte Hypertrophy by Activating AMP-Activated Protein Kinase
No full textBackground/Objectives: Metabolites produced by gut microbiota play an important role in the crosstalk between the gut and other organs. Although HYA (10-hydroxy-cis-12-octadecenoic acid), a linoleic acid metabolite produced by lactic acid bacteria represented by Lactobacillus, has been shown to exert physiological effects such as metabolic improvement and anti-inflammation in the host, its direct action on adipose tissue and the mechanism remains unknown. Methods: The effect of HYA administration on adipocyte size in mice fed a high-fat diet was examined. In 3T3-L1 mature adipocytes treated with HYA, the amount of intracellular lipid droplets was evaluated by Oil red O staining, gene expression by real-time qPCR, phosphorylation of AMP-activated protein kinase (AMPK) by immunoblotting, and intracellular Ca2+ concentration with calcium imaging. Results: Administration of HYA, but not linoleic acid, to obese mice fed a high-fat diet significantly reduced adipocyte size. To investigate whether the inhibition of adipocyte hypertrophy by HYA has a direct effect on adipocytes, 3T3-L1 adipocytes were treated with HYA, which significantly decreased the amount of intracellular lipid droplets in these cells. Gene expression analysis by real-time PCR showed decreased expression of genes related to lipogenesis such as FAS and ACC1, and increased expression of CPT1A, which is involved in fatty acid oxidation. Mechanistically, HYA was found to activate AMPK in adipocytes by increasing intracellular Ca2+ concentration. Conclusions: HYA suppresses adipocyte hypertrophy by activating AMPK in adipocytes. HYA may be a potential therapeutic for obesity and related metabolic disorders
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