Chemical abundance analysis of 19 barium stars

We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures, surface gravities, metallicity and microturbulent velocity) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their light elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn and Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-capture) process elements relative to the Sun. Their median abundances of [Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The YI and ZrI abundances are lower than Ba, La and Eu, but higher than the light elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe]. For the n-capture elements (Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe]>0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17<[Ba/Fe]<0.54

Self-field effects upon the critical current density of flat superconducting strips

We develop a general theory to account self-consistently for self-field effects upon the average transport critical current density Jc of a flat type-II superconducting strip in the mixed state when the bulk pinning is characterized by a field-dependent depinning critical current density Jp(B), where B is the local magnetic flux density. We first consider the possibility of both bulk and edge-pinning contributions but conclude that bulk pinning dominates over geometrical edge-barrier effects in state-of-the-art YBCO films and prototype second-generation coated conductors. We apply our theory using the Kim model, JpK(B) = JpK(0)/(1+|B|/B0), as an example. We calculate Jc(Ba) as a function of a perpendicular applied magnetic induction Ba and show how Jc(Ba) is related to JpK(B). We find that Jc(Ba) is very nearly equal to JpK(Ba) when Ba > Ba*, where Ba* is the value of Ba that makes the net flux density zero at the strip's edge. However, Jc(Ba) is suppressed relative to JpK(Ba) at low fields when Ba < Ba*, with the largest suppression occurring when Ba*/B0 is of order unity or larger.Comment: 9 pages, 4 figures, minor revisions to add four reference

The ergogenic effect of beta-alanine combined with sodium bicarbonate on high-intensity swimming performance

We investigated the effect of beta-alanine (BA) alone (study A) and in combination with sodium bicarbonate (SB) (study B) on 100- and 200-m swimming performance. In study A, 16 swimmers were assigned to receive either BA (3.2 g·day−1 for 1 week and 6.4 g·day−1 for 4 weeks) or placebo (PL; dextrose). At baseline and after 5 weeks of supplementation, 100- and 200-m races were completed. In study B, 14 were assigned to receive either BA (3.2 g·day−1 for 1 week and 6.4 g·day−1 for 3 weeks) or PL. Time trials were performed once before and twice after supplementation (with PL and SB), in a crossover fashion, providing 4 conditions: PL-PL, PL-SB, BA-PL, and BA-SB. In study A, BA supplementation improved 100- and 200-m time-trial performance by 2.1% (p = 0.029) and 2.0% (p = 0.0008), respectively. In study B, 200-m time-trial performance improved in all conditions, compared with presupplementation, except the PL-PL condition (PL-SB, +2.3%; BA-PL, +1.5%; BA-SB, +2.13% (p < 0.05)). BA-SB was not different from BA-PL (p = 0.21), but the probability of a positive effect was 78.5%. In the 100-m time-trial, only a within-group effect for SB was observed in the PL-SB (p = 0.022) and BA-SB (p = 0.051) conditions. However, 6 of 7 athletes swam faster after BA supplementation. The probability of BA having a positive effect was 65.2%; when SB was added to BA, the probability was 71.8%. BA and SB supplementation improved 100- and 200-m swimming performance. The coingestion of BA and SB induced a further nonsignificant improvement in performance

How do top- and bottom-performing companies differ in using business analytics?

Purpose Business analytics (BA) has attracted growing attention mainly due to the phenomena of big data. While studies suggest that BA positively affects organizational performance, there is a lack of academic research. The purpose of this paper, therefore, is to examine the extent to which top- and bottom-performing companies differ regarding their use and organizational facilitation of BA. Design/methodology/approach Hypotheses are developed drawing on the information processing view and contingency theory, and tested using multivariate analysis of variance to analyze data collected from 117 UK manufacture companies. Findings Top- and bottom-performing companies differ significantly in their use of BA, data-driven environment, and level of fit between BA and data-drain environment. Practical implications Extensive use of BA and data-driven decisions will lead to superior firm performance. Companies wishing to use BA to improve decision making and performance need to develop relevant analytical strategy to guide BA activities and design its structure and business processes to embed BA activities. Originality/value This study provides useful management insights into the effective use of BA for improving organizational performance

Stellar laboratories III. New Ba V, Ba VI, and Ba VII oscillator strengths and the barium abundance in the hot white dwarfs G191-B2B and RE0503-289

For the spectral analysis of high-resolution and high-signal-to-noise (S/N) spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that is used for their calculation. Reliable Ba V - VII oscillator strengths are used to identify Ba lines in the spectra of the DA-type white dwarf G191-B2B and the DO-type white dwarf RE0503-289 and to determine their photospheric Ba abundances. We newly calculated Ba V - VII oscillator strengths to consider their radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models for the analysis of Ba lines exhibited in high-resolution and high-S/N UV observations of G191-B2B and RE0503-289. For the first time, we identified highly ionized Ba in the spectra of hot white dwarfs. We detected Ba VI and Ba VII lines in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of RE0503-289. The Ba VI / Ba VII ionization equilibrium is well reproduced with the previously determined effective temperature of 70000 K and surface gravity of $\log g = 7.5$. The Ba abundance is $3.5 \pm 0.5 \times 10^{-4}$ (mass fraction, about 23000 times the solar value). In the FUSE spectrum of G191-B2B, we identified the strongest Ba VII line (at 993.41 \AA) only, and determined a Ba abundance of $4.0 \pm 0.5 \times 10^{-6}$ (about 265 times solar). Reliable measurements and calculations of atomic data are a pre-requisite for stellar-atmosphere modeling. Observed Ba VI - VII line profiles in two white dwarfs' (G191-B2B and RE0503-289) far-ultraviolet spectra were well reproduced with our newly calculated oscillator strengths. This allowed to determine the photospheric Ba abundance of these two stars precisely.Comment: 36 pages, 8 figure

Aggregation in a mixture of Brownian and ballistic wandering particles

In this paper, we analyze the scaling properties of a model that has as limiting cases the diffusion-limited aggregation (DLA) and the ballistic aggregation (BA) models. This model allows us to control the radial and angular scaling of the patterns, as well as, their gap distributions. The particles added to the cluster can follow either ballistic trajectories, with probability $P_{ba}$, or random ones, with probability $P_{rw}=1-P_{ba}$. The patterns were characterized through several quantities, including those related to the radial and angular scaling. The fractal dimension as a function of $P_{ba}$ continuously increases from $d_f\approx 1.72$ (DLA dimensionality) for $P_{ba}=0$ to $d_f\approx 2$ (BA dimensionality) for $P_{ba}=1$. However, the lacunarity and the active zone width exhibt a distinct behavior: they are convex functions of $P_{ba}$ with a maximum at $P_{ba}\approx1/2$. Through the analysis of the angular correlation function, we found that the difference between the radial and angular exponents decreases continuously with increasing $P_{ba}$ and rapidly vanishes for $P_{ba}>1/2$, in agreement with recent results concerning the asymptotic scaling of DLA clusters.Comment: 7 pages, 6 figures. accepted for publication on PR

Structure and electronic properties of the quasi-one-dimensional Ba₂Co₁₋ₓZnₓS₃ series

This work focuses on the structure and physical properties of the solid solution Ba₂Co₁₋ₓZnₓS₃ (0 ≤ x ≤ 1), a family of quasi-one-dimensional sulfides with end members Ba₂CoS₃ and Ba₂ZnS₃. The structure of selected compounds with increasing Zn²⁺ content has been analysed using, neutron diffraction, TEM and EXAFS and the physical properties via magnetic susceptibility and resistivity measurements. The progressive substitution of the non-magnetic Zn²⁺ cation for Co²⁺ rapidly destroys the antiferromagnetic transition present at 46 K in the quasi one-dimensional Ba₂CoS₃, leading to paramagnetic behaviour down to the lowest investigated temperature (5K) for compounds with x > 0.25. For compounds with x ≥ 0.4, a pure CW regime is recovered around 300 K, yielding effective moments consistent with the g factor of the tetrahedrally coordinated Co²⁺ previously determined for Ba₂CoS₃. The Zn²⁺/Co²⁺ substitution also removes the metallic-like behaviour of Ba₂CoS₃ causing an increase in the value of the resistivity with all the Ba₂Co₁₋ₓZnₓS₃ compounds showing semiconducting behaviour. The negative magnetoresistance of Ba₂CoS₃ is improved by the Zn²⁺/Co²⁺ substitution, with values of – 6% for Ba₂Co₀.₇₅Zn₀.₂₅S₃, – 9% for Ba₂Co₀.₅Zn₀.₅S₃ and – 8% for Ba₂Co₀.₂₅Zn₀.₇₅S₃. However, there does not seem to be a correlation between the values of the resistivity and the magnetoresistance and the content of Zn²⁺, leading to the hypothesis that transport properties may be linked more closely to extrinsic properties

Developmental toxic effects of ethylbenzene or toluene alone and in combination with butyl acetate in rats after inhalation exposure

First, the developmental toxic potential of n-butyl acetate (BA) was examined in Sprague-Dawley rats following whole body inhalation exposure, 6 h day-1, from day 6 to 20 of gestation, at concentrations of 0, 500, 1000, 2000 and 3000 ppm. Maternal toxicity was evidenced by significant decreases in body weight gain at 2000 and 3000 ppm, and by reduced food consumption at 1000 ppm and higher concentrations. The effects on prenatal development were limited to a significant decrease in fetal weight at 3000 ppm. Thus, inhaled BA was not a selective developmental toxicant. In the second part of this study, the developmental toxic effects of simultaneous exposures to ethylbenzene (EB) and BA, or to toluene (TOL) and BA were evaluated. Pregnant rats were administered EB (0, 250 or 1000 ppm) and BA (0, 500 or 1500 ppm), or TOL (0, 500 or 1500 ppm) and BA (0, 500, 1500 ppm), separately and in combinations, using a 2 × 2 factorial design. The maternal weight gain was reduced after exposure to 1000 ppm EB, to 1500 ppm BA, or to 1500 ppm TOL, either alone or in binary combinations. A significant reduction of fetal weight was associated with exposure to 1000 ppm EB alone, to either mixtures of EB with BA, or to 1500 ppm TOL alone or combined with BA at either concentration. No embryolethal or teratogenic effects were observed whatever the exposure. There was no evidence of interaction between EB and BA or between TOL and BA in causing maternal or developmental effects. Copyright © 2006 John Wiley & Sons, Ltd

Regeneration of begonia plantlets by direct organogenesis

The economic importance of ornamentals worldwide suggests a bright future for ornamental breeding. Rapid progress in plant molecular biology has great potentials to contribute to the breeding of novel ornamental plants utilizing recombinant DNA technology. The plant cell, tissue or organ culture of many ornamental species and their regeneration are essential for providing the material and systems for their genetic manipulation, and this is therefore the first requirement of genetic engineering. In this research, different concentration of BA (0.0, 0.5, 1.0, 2.0 mgl(-1) with NAA ( 0.0, 0.5, 1.0 mgl(-1)) and BA (0.0, 0.5, 1.0, 2.0 mgl(-1)) with IAA ( 0.0, 0.5, 1.0, mgl(-1)) were investigated to optimize regeneration of Begonia elatior cv. Toran orange. The best regeneration and growth were obtained from the media containing 2.0 mgl(-1) BA and 1.0 mgl(-1) NAA (70%) followed by 1.0 mgl(-1) BA and 0.5 mgl(-1) NAA (50%), 1.0 mgl(-1) BA and 1.0 mgl(-1) NAA (20%) in BA - NAA combination. The media with BA - IAA combination showed that the best regeneration was 0.5 mgl(-1) BA and 0.5 mgl(-1) IAA (43%) followed by 0.5 mgl(-1) BA and 1.0 mgl(-1) IAA (23%)