Search results for "equivalent"
showing 10 items of 308 documents
Maternal body mass index, change in weight status from childhood to late adulthood and physical activity in older age
2021
This study aimed to examine the longitudinal associations of maternal body mass index (BMI), weight status in childhood and late adulthood and device-measured total physical activity (TPA) in older age. The study involves 552 participants from Helsinki Birth Cohort Study who were born in Helsinki, Finland, in 1934-1944. TPA was measured with a multisensory body monitor at a mean age of 70 years and expressed in metabolic equivalent of task hours/day (METh/d). Childhood overweight (BMI > 85th percentile) was based on school health records at 6-7 years of age, and late adulthood overweight (BMI >= 25 kg/m(2)) was based on clinical measurements at the mean age of 61 years. Childhood overweight…
The excitation of circumstellar C2in carbon-rich post-AGB object IRAS 22272+5435
2013
Context. Observations of the circumstellar envelopes of post-asymptotic giant branch (post-AGB) stars provide information about their mass-loss history during the AGB phase and about the chemistry inside envelopes after that phase. Aims. We analyze visual observations of C2 molecule in absorption and millimeter and sub-millimeter observations of CO molecule in emission with the aim of determining the physical and chemical conditions in the circumstellar shell of the carbon-rich post-AGB star IRAS 22272+5435. Methods. We determined the column densities and excitation structure of C2 from equivalent width analysis of the molecular absorptions. The thermal and density structure of post-AGB she…
Design of Zero-Ripple-Current Coupled Inductors With PWM Signals in Continuous Conduction Mode
2021
Coupled inductors are widely used in multiple outputs and interleaved dc–dc converters. Also filters often use coupled inductors as their inductive part. A generalized design procedure is proposed in this article focused on current ripple minimization and applicable to coupled inductors exposed to pulsewidth modulation signals and in continuous conduction mode. The design provides a very large inductance for all windings but one. Compared to other designs, it adapts to the existing magnetic properties of the magnetic device changing only the inductance ratio, simplifying the design and manufacturing process. It is based on the equivalent inductance value and its divergences. The only assump…
Quantifying the contamination by old main-sequence stars in young moving groups: the case of the Local Association
2009
The associations and moving groups of young stars are excellent laboratories for investigating stellar formation in the solar neighborhood. Previous results have confirmed that a non-negligible fraction of old main-sequence stars is present in the lists of possible members of young stellar kinematic groups. A detailed study of the properties of these samples is needed to separate the young stars from old main-sequence stars with similar space motion, and identify the origin of these structures. We used stars possible members of the young (~ 10 - 650 Myr) moving groups from the literature. To determine the age of the stars, we used several suitable age indicators for young main sequence star…
VLT/Flames observations of the star forming region NGC 6530
2006
Mechanisms regulating the evolution of pre-main sequence stars can be understood by studying stellar properties such as rotation, disk accretion, internal mixing and binarity. To investigate such properties, we studied a sample of 332 candidate members of the massive and populous star forming region NGC 6530. We want to select cluster members by using different membership criteria,to study the properties of pre-main sequence stars with or without circumstellar disks. We use intermediate resolution spectra including the Li I 6707.8 Angstroms line to derive radial and rotational velocities, binarity and to measure the Equivalent Width of the lithium line; these results are combined with X-ray…
The X-ray emission of the supernova remnant W49B observed withXMM-Newton
2006
In the framework of the study of supernova remnants and their complex interaction with the interstellar medium, we report on an XMM-Newton EPIC observation of the Galactic supernova remnant W49B. We investigate the spatial distribution of the chemical and physical properties of the plasma, so as to get important constraints on the physical scenario, on the dynamics of the supernova explosion, and on the interaction of the supernova remnant with the ambient interstellar clouds. We present line images, equivalent width maps, and a spatially resolved spectral analysis of a set of homogeneous regions. The X-ray spectrum of W49B is characterized by strong K emission lines from Si, S, Ar, Ca and …
Physical and Chemical Inhomogeneities Inside the Vela SNR Shell: Indications of Ejecta Shrapnels
2007
We present the results of the combined analysis of three XMM-Newton EPIC observations of the northern rim of the Vela SNR. The three pointings cover an area of ~10 pc^2 (at 250 pc) behind the main shock front and we aim at studying with high resolution the spatial distribution of the physical and chemical properties of the X-ray emitting plasma on this large scale. We produce count-rate images and equivalent width maps of the Ne IX and Mg XI emission blends. We also perform a spatially resolved spectral analysis of a set of physically homogeneous regions. We reveal physical and chemical inhomogeneities in the X-ray emitting plasma. In particular, we find large variations of the O, Ne, Mg, a…
Long-term optical/IR variability of the Be/X-ray binary LS V +44 17/RX J0440.9+4431
2005
We present the first long-term study of the optical counterpart to the X-ray pulsar LS V +44 17/RX J0440.9+4431. The results of our photometric and spectroscopic analysis show that LS V +44 17/RX J0440.9+4431 contains a moderately reddened, E(B-V)=0.65+-0.05, B0.2V star located at about 3.3 kpc. The Ha line consistently shows a double-peak profile varying from symmetric shape to completely distorted on one side (V/R phases). A correlation between the equivalent width of the Ha line and the infrared magnitudes is seen: as the EW(Ha) decreases the IR magnitudes become fainter. This long-term optical/IR variability is attributed to structural changes in the Be star's circumstellar disc. The ob…
Long-term variability of the Be/X-ray binary A 0535+26 -- I. Optical and UV spectroscopy
1998
The results of a 7-yr optical and UV spectroscopic study of the high-mass X-ray binary A 0535+26 are presented. It was found that throughout the period of the observations the line profile of Hα showed considerable variability. A correlation between the equivalent width of Hα and both V-band magnitude and (B−V) colour excess was observed, albeit with considerable scatter present in the data set. A giant X-ray flare in early 1994 was accompanied by a fading in optical and infrared photometric bands, and a reduction in the equivalent width of Hα. When the star was observed in 1994 September, it was found to have developed a double-peaked Hα profile, and further observations saw the V/R peak r…
Simultaneous uvbyβ Photometry and Hα Spectroscopy of Be Stars in Open Clusters
1994
The usual methods of spectral clasification, equivalent widths of Balmer lines or photometric calibrations are not suitable for the determination of the astrophysical parameters of the underlying star in Be-type objects. The spectrum is distorted by the circumstellar envelope lines, while the contribution of the envelope continuum radiation contaminates the photometric indices.