scholarly journals The Chromosphere of β Cassiopeiae

1989 ◽  
Vol 111 ◽  
pp. 286-286
Author(s):  
Terry J. Teays ◽  
Edward G. Schmidt ◽  
Massimo Fracassini ◽  
Laura E. Pasinetti Fracassini
Keyword(s):  
Line Profile ◽  
High Dispersion ◽  
Emission Flux ◽  
Long Wavelength ◽  
Maximum Light ◽  
Classical Cepheids ◽  
Scuti Star ◽  
The Mean ◽  
Emission Core ◽  
Photometric Variation

AbstractWe have carried out high dispersion, long wavelength IUE observations and ground based photometry of the δ Scuti star, β Cas. Our ground based observations were used, together with the previous results of Antonello et al. (1986, I.B.V.S. 2958, 1986), to ensure that the IUE observations were correctly phased relative to the photometric variation. Fluxes for the emission core of the Mg II k line (2796 Å) were obtained from 23 ultraviolet spectra taken over several cycles in 1986 and 1987. The emission flux, if present, was measured with respect to the mean line profile of all of the spectra. Emission was present at phases between 0.4 and 0.5. This is in contrast to what has been observed for another δ Scuti star, ρ Pup, and for the classical Cepheids, where the emission appeared at maximum light.

Contrast of Filament Bright Rims

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč
Keyword(s):  
High Altitude ◽  
Line Profile ◽  
Line Center ◽  
Magnetic Structures ◽  
The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

Quasi-Experimental study of effects of lighting on rest, activity and melatonin in postpartum women

2021 ◽  
Vol 74 (6) ◽  
Author(s):  
Cristina Furtado Volcov ◽  
Eliana Moreira Pinheiro ◽  
Miriam Harumi Tsunemi ◽  
Fernanda Gaspar do Amaral ◽  
Ariane Ferreira Machado Avelar ◽  
...  
Keyword(s):  
Experimental Study ◽  
Comparison Group ◽  
Total Load ◽  
Long Wavelength ◽  
Light Regimen ◽  
Early Postpartum ◽  
Comparison Groups ◽  
Quasi Experimental ◽  
The Mean ◽  
Experimental Group

ABSTRACT Objectives: to compare the parameters of the activity/rest cycle of early postpartum breastfeeding women under a controlled and uncontrolled long wavelength ray light regimen. Methods: quasi-experimental study with breastfeeding women and their babies during postnatal rooming-in, São Paulo, Brazil. Participants were allocated to either an experimental (intervention) or a comparison group. The intervention involved exposure of the woman in a controlled room with artificial long wavelength ray light at night. Each woman’s level of 6-sulfatoxymelatonin at 24 hours and activity/rest times was analyzed. Results: the mean activity/rest times of women in the experimental and comparison groups were similar. The mean percentages of total load of 6-sulfatoxymelatonin during the day and night were similar (p=0.09). At 24 hours, the experimental group presented a significantly lower mean percentage of total load compared to the comparison group (p=0.04). Conclusions: women who stayed in the room with long-wavelength artificial light showed no difference in activity/rest and 6-sulfatoxymelatonin levels in the early postpartum period.

Ca II Emission from Late-type Stars

1983 ◽  
Vol 5 (2) ◽  
pp. 152-157 ◽  
Author(s):  
L. E. Cram
Keyword(s):  
Line Profile ◽  
Strong Correlation ◽  
Velocity Fields ◽  
Line Profiles ◽  
Late Type ◽  
Wide Range ◽  
Cool Stars ◽  
Visual Magnitude ◽  
The Absolute ◽  
Emission Core

Two recent observational surveys of the Ca II resonance lines (Zarro and Rodgers 1983; Linsky et al. 1979) illustrate the great diversity of line profile shapes found in the spectra of cool stars. This diversity reflects a corresponding wide range in the underlying chromospheric properties of the stars. There are, however, three well-marked systematic trends in the shapes of Ca II line profiles which presumably reflect systematic trends in chromospheric properties. One of these, the Wilson-Bappu effect (Wilson and Bappu 1957), describes the strong correlation betweeen the width of the emission core (see Figure 1) and the absolute visual magnitude of the star. Despite much work, it is still not clear whether this is due primarily to systematic changes of velocity fields (e.g. Hoyle and Wilson 1958) or optical depths (e.g. Jefferies and Thomas 1959) in stellar chromospheres.

scholarly journals Time-series analysis of the O4 supergiant ζ Puppis

1994 ◽  
Vol 162 ◽  
pp. 112-113
Author(s):  
Andy Reid
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Line Profile ◽  
High Dispersion ◽  
High Signal ◽  
Series Analysis ◽  
Wind Variability ◽  
Optical Line ◽  
Qualitative Pattern ◽  
The Individual

Preliminary results of a time-series analysis on a sequence of high dispersion, high-signal-to-noise, optical echelle spectra of the O4 supergiant, ζ Puppis (HD 66811), are presented. Lines of Hei λ5876Å, Heii λ5411Å, Niv λ6381Å and Civ λλ5801, 5812Å are analysed; they show variations in line shape and equivalent width, with ‘bumps’ and ‘dips’ seen moving from blue to red within the line profile. The qualitative pattern of variability seen in all these lines is similar.A Fourier technique, incorporating the iterative clean algorithm, was used on the individual wavelength samples. A periodicity of 8.5-hrs was detected in Heii, and strongly suspected in the remaining absorption lines. This periodicity seems to rule out wind variability as the principal origin for the optical line profile variations seen in ζ Puppis.

scholarly journals Mermin–Wagner fluctuations in 2D amorphous solids

2017 ◽  
Vol 114 (8) ◽  
pp. 1856-1861 ◽  
Author(s):  
Bernd Illing ◽  
Sebastian Fritschi ◽  
Herbert Kaiser ◽  
Christian L. Klix ◽  
Georg Maret ◽  
...  
Keyword(s):  
Computer Simulations ◽  
System Size ◽  
Amorphous Solids ◽  
Two Dimensions ◽  
Density Fluctuations ◽  
Long Wavelength ◽  
Broken Symmetries ◽  
Lindemann Criterion ◽  
The Mean ◽  
2D Crystals

In a recent commentary, J. M. Kosterlitz described how D. Thouless and he got motivated to investigate melting and suprafluidity in two dimensions [Kosterlitz JM (2016)J Phys Condens Matter28:481001]. It was due to the lack of broken translational symmetry in two dimensions—doubting the existence of 2D crystals—and the first computer simulations foretelling 2D crystals (at least in tiny systems). The lack of broken symmetries proposed by D. Mermin and H. Wagner is caused by long wavelength density fluctuations. Those fluctuations do not only have structural impact, but additionally a dynamical one: They cause the Lindemann criterion to fail in 2D in the sense that the mean squared displacement of atoms is not limited. Comparing experimental data from 3D and 2D amorphous solids with 2D crystals, we disentangle Mermin–Wagner fluctuations from glassy structural relaxations. Furthermore, we demonstrate with computer simulations the logarithmic increase of displacements with system size: Periodicity is not a requirement for Mermin–Wagner fluctuations, which conserve the homogeneity of space on long scales.

Thermocapillary flows on heated substrates with sinusoidal topography

2018 ◽  
Vol 859 ◽  
pp. 992-1021 ◽  
Author(s):  
Jaehyun Yoo ◽  
Jaewook Nam ◽  
Kyung Hyun Ahn
Keyword(s):  
Liquid Layer ◽  
Asymptotic Theory ◽  
Buoyancy Effect ◽  
Uniform Temperature ◽  
Small Aspect Ratio ◽  
Vertical Diffusion ◽  
Long Wavelength ◽  
Thermocapillary Flows ◽  
Basic Solutions ◽  
The Mean

Two-dimensional steady thermocapillary flows in a liquid layer over a substrate, which has a uniform temperature and sinusoidal topography, are investigated by asymptotic theory. Here, the buoyancy effect is negligible and the interface is not significantly disturbed under low Marangoni number and low capillary number. A temperature gradient along the gas/liquid interface causes recirculating flows. For a small aspect ratio, which yields a sinusoidal topography with a long wavelength relative to the mean depth of the liquid layer, the second-order solutions are obtained analytically. The basic solutions show vertical diffusion of heat and vorticity from the substrate and interface, respectively. In the second corrections, the horizontal diffusion of heat weakens the overall flow and the convection of heat intensifies it.

scholarly journals The fast rotating δ Scuti pulsator V376 Per: Frequency analysis and mode identification

2013 ◽  
Vol 9 (S301) ◽  
pp. 499-500
Author(s):  
Nathalie Themessl ◽  
Veronique Fritz ◽  
Michel Breger ◽  
Sabine Karrer ◽  
Barbara G. Castanheira
Keyword(s):  
High Resolution ◽  
Line Profile ◽  
Frequency Analysis ◽  
Spectroscopic Data ◽  
Simultaneous Analysis ◽  
Stellar Spectra ◽  
Mode Identification ◽  
Pulsation Mode ◽  
Scuti Star ◽  
Fast Rotating

AbstractOur simultaneous analysis of ground-based photometric and high-resolution spectroscopic data of the δ Scuti star V376 Per revealed eight individual frequencies from 82 nights of two-color photometry and six frequencies from the line-profile variations using 769 stellar spectra. Additionally, we identified the corresponding pulsation modes and derived reliable estimates of the line profile and pulsation mode parameters.

ON ELASTIC VIBRATIONS OF HOMOGENEOUS STAR

1993 ◽  
Vol 08 (08) ◽  
pp. 711-714 ◽  
Author(s):  
SERGEY I. BASTRUKOV
Keyword(s):  
Analytical Form ◽  
Mean Velocity ◽  
Elastic Vibrations ◽  
Long Wavelength ◽  
The Mean ◽  
Elastic Strains

The long wavelength vibrations of a homogeneous star are studied in the model of an incompressible self-gravitating elastic globe. The dynamics of stellar continuum is described in terms of macroscopic fields of the density, the mean velocity and the tensor of elastic strains. The frequency of normal elastic-gravitational vibrations is derived in analytical form.

scholarly journals Simultaneous Chemical Reactions Effect on Dispersion of a Solute in Peristaltic Propulsion of a Newtonian Fluid in an Inclined Channel with Wall Properties

2019 ◽  
Vol 24 (3) ◽  
pp. 527-538
Author(s):  
M.Y. Dhange ◽  
G.C. Sankad
Keyword(s):  
Viscous Fluid ◽  
Chemical Reactions ◽  
Effective Coefficient ◽  
Long Wavelength ◽  
Inclined Channel ◽  
Heterogeneous Chemical ◽  
Wall Properties ◽  
Uniform Channel ◽  
The Mean ◽  
Heterogeneous Chemical Reactions

Abstract In this paper, the dispersion of a solute in the peristaltic propulsion of an incompressible and viscous fluid through a permeable medium under the influence of wall properties with simultaneous homogeneous, heterogeneous chemical reactions in an inclined uniform channel has been studied. The issue is studied through conditions of Taylor’s limit and long wavelength hypothesis. The mean effective coefficient of scattering expression is computed and outcomes are interpreted physically through graphs.

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