The enigmatic He-sdB pulsator LS IV−-14∘^\circ116: new insights from the VLT

The intermediate Helium subdwarf B star LS IV$-$14$^\circ$116 is a unique object showing extremely peculiar atmospheric abundances as well as long-period pulsations that cannot be explained in terms of the usual opacity mechanism. One hypothesis invoked was that a strong magnetic field may be responsible. We discredit this possibility on the basis of FORS2 spectro-polarimetry, which allows us to rule out a mean longitudinal magnetic field down to 300 G. Using the same data, we derive the atmospheric parameters for LS IV$-$14$^\circ$116 to be $T_{\rm eff}$ = 35,150$\pm$111 K, $\log{g}$ = 5.88$\pm$0.02 and $\log{N(\rm He)/N(\rm H)}$ = $-$0.62$\pm$0.01. The high surface gravity in particular is at odds with the theory that LS IV$-$14$^\circ$116 has not yet settled onto the Helium Main Sequence, and that the pulsations are excited by an $\epsilon$ mechanism acting on the Helium-burning shells present after the main Helium flash. Archival UVES spectroscopy reveals LS IV$-$14$^\circ$116 to have a radial velocity of 149.1$\pm$2.1 km/s. Running a full kinematic analysis, we find that it is on a retrograde orbit around the Galactic centre, with a Galactic radial velocity component $U$=13.23$\pm$8.28 km/s and a Galactic rotational velocity component $V$=$-$55.56$\pm$22.13 km/s. This implies that LS IV$-$14$^\circ$116 belongs to the halo population, an intriguing discovery.Comment: accepted for publication in A&

On the thin-string limit of the 6d stringlike defect model

We show that in 6d models localizing gravity on stringlike defects and satisfying the dominant energy condition, the metric exterior to the string inevitably depends on the string's thickness. As a consequence, in the limit of thin string either the gravity delocalizes, or the six-dimensional Planck scale must be much larger that the four-dimensional one.Comment: 3 pages; v2: an alternative interpretation of our results, overlooked in the first version, is adde

Generation of spin-motion entanglement in a trapped ion using long-wavelength radiation

Applying a magnetic-field gradient to a trapped ion allows long-wavelength radiation to produce a mechanical force on the ion's motion when internal transitions are driven. We demonstrate such a coupling using a single trapped Yb+171 ion and use it to produce entanglement between the spin and motional state, an essential step toward using such a field gradient to implement multiqubit operations

PANEL STRATIFICATION IN META-ANALYSIS OF ENVIRONMENTAL AND NATURAL RESOURCE ECONOMIC STUDIES

Meta-analyses of past research outcomes are becoming more popular, however, the issue of the panel nature of data has not been empirically investigated. We test various forms of data stratifications into panels for outdoor recreation economic studies but do not find any significant effects, possibly because of inherent data complexity.Environmental Economics and Policy, Resource /Energy Economics and Policy,

Transnational Trafficking, Law Enforcement and Victim Protection: A Middleman Trafficker's Perspective

We explore three hitherto poorly understood characteristics of the human trafficking market – the cross-border ease of mobility of traffickers, the relative bargaining strength of traffickers and final buyers, and the elasticity of buyers' demand. In a model of two-way bargaining, the exact configuration of these characteristics is shown to determine whether domestic and foreign crackdowns on illicit employment mutually reinforce or counteract one another in efforts to stem the tide of trafficking. Estimation results from a gravity model of trafficking present evidence consistent with the mutual reinforcement view, indicating considerable ease of mobility, partial bargaining power, and inelastic demand.human trafficking, two-way Nash bargaining, victim protection, law enforcement

Some solutions of linearized 5-d gravity with brane

We consider linearized 5-d gravity in the Randall-Sundrum brane world. The class of static solutions for linearized Einstein equations is found. Also we obtaine wave solutions describing radiation from an imaginary point source located at the Planck distance from the brane. We analyze the fields asymptotic behavior and peculiarities of matter sources.Comment: Latex, 8 page

Radius-dependent gauge unification in AdS5

We examine the relation of the 4-dimensional low energy coupling of bulk gauge boson in a slice of AdS5 to the 5-dimensional fundamental couplings as a function of the orbifold radius R. This allows us to address the gauge coupling unification in AdS5 by means of the radius running as well as the conventional momentum running. We then compute the radius dependence of 1-loop low energy couplings in generic AdS5 theory with 4-dimensional supersymmetry, and discuss the low energy predictions when the 5-dimensional couplings are assumed to be unified.Comment: 11 pages, 2 figures, revtex, v3: analysis was generalized to S^1/Z_2*Z_2 orbifoldin

Observations and asteroseismological analysis of the rapid subdwarf B pulsator EC 09582-1137

We made photometric and spectroscopic observations of the rapidly pulsating subdwarf B star EC 09582-1137 with the aim of determining the target's fundamental structural parameters from asteroseismology. The new data comprise ~ 30 hours of fast time-series photometry obtained with SUSI2 at the NTT on La Silla, Chile, as well as 1 hour of low-resolution spectroscopy gathered with EMMI, also mounted on the NTT. From the photometry we detected 5 independent harmonic oscillations in the 135-170 s period range with amplitudes up to 0.5% of the mean brightness of the star. In addition, we extracted two periodicities interpreted as components of a rotationally split multiplet that indicate a rotation period of the order of 2-5 days. We also recovered the first harmonic of the dominant pulsation, albeit at an amplitude below the imposed 4-sigma detection threshold. The spectroscopic observations led to the following estimates of the atmospheric parameters of EC 09582-1137: Teff = 34,806+-233 K, log g = 5.80+-0.04, and log[N(He)/N(H)] = - 1.68+-0.06. Using the observed oscillations as input, we searched in model parameter space for unique solutions that present a good fit to the data. Under the assumption that the two dominant observed periodicities correspond to radial or dipole modes, we were able to isolate a well-constrained optimal model that agrees with the atmospheric parameters derived from spectroscopy. The inferred structural parameters of EC 09582-1137 are Teff = 34,806 K (from spectroscopy), log g = 5.788+-0.004, M = 0.485+-0.011 M_solar, log(M_env/M_star) = - 4.39+-0.10, R = 0.147+-0.002 R_solar, and L = 28.6+-1.7 L_solar. We additionally derive the absolute magnitude M_V = 4.44+-0.05 and the distance d = 1460+-66 pc.Comment: accepted for publication in Astronomy and Astrophysic