Dynamical Ne K Edge and Line Variations in the X-Ray Spectrum of the Ultra-compact Binary 4U 0614+091

We observed the ultra-compact binary candidate 4U 0614+091 for a total of 200 ksec with the high-energy transmission gratings onboard the \chandra X-ray Observatory. The source is found at various intensity levels with spectral variations present. X-ray luminosities vary between 2.0$\times10^{36}$ \ergsec and 3.5$\times10^{36}$ \ergsec. Continuum variations are present at all times and spectra can be well fit with a powerlaw component, a high kT blackbody component, and a broad line component near oxygen. The spectra require adjustments to the Ne K edge and in some occasions also to the Mg K edge. The Ne K edge appears variable in terms of optical depths and morphology. The edge reveals average blue- and red-shifted values implying Doppler velocities of the order of 3500 \kms. The data show that Ne K exhibits excess column densities of up to several 10$^{18}$ cm$^{-2}$. The variability proves that the excess is intrinsic to the source. The correponding disk velocities also imply an outer disk radius of the order of $< 10^9$ cm consistent with an ultra-compact binary nature. We also detect a prominent soft emission line complex near the \oviii L$\alpha$ position which appears extremely broad and relativistic effects from near the innermost disk have to be included. Gravitationally broadened line fits also provide nearly edge-on angles of inclination between 86 and 89$^{\circ}$. The emissions appear consistent with an ionized disk with ionization parameters of the order of 10$^4$ at radii of a few 10$^7$ cm. The line wavelengths with respect to \oviiia\ are found variably blue-shifted indicating more complex inner disk dynamics.Comment: 24 pages, 8 figures, submitted to the Astrophyscial Main Journa

The effect of education on in-prison conflict: evidence from Argentina

Using census data for Argentine prisons for the period 2002-2005, this paperpresents evidence of the positive e¤ect that prisoner education programs (pri-mary and some part of secondary schooling) have on in prison conflictivitymeasured as sanctions or violent behavior of the prisoner. In order to over-come the problems of endogeneity that education decisions generate we usean instrumental variables approach. Our results show a decrease in partici-pation in violent conflicts and bad behavior which can be partially attributedto education.prison based education, violent behavior

Canonical interpretation of Y(10750)Y(10750) and Υ(10860)\Upsilon(10860) in the Υ\Upsilon family

Inspired by the new resonance $Y(10750)$, we calculate the masses and two-body OZI-allowed strong decays of the higher vector bottomonium sates within both screened and linear potential models. We discuss the possibilities of $\Upsilon(10860)$ and $Y(10750)$ as mixed states via the $S-D$ mixing. Our results suggest that $Y(10750)$ and $\Upsilon(10860)$ might be explained as mixed states between $5S$- and $4D$-wave vector $b\bar{b}$ states. The $Y(10750)$ and $\Upsilon(10860)$ resonances may correspond to the mixed states dominated by the $4D$- and $5S$-wave components, respectively. The mass and the strong decay behaviors of the $\Upsilon(11020)$ resonance are consistent with the assignment of the $\Upsilon(6S)$ state in the potential models.Comment: 9 pages, 4 figures. More discussions are adde

Job Changes and Wage Dynamics

In this paper we investigate the relation between wage growth and labour mobility on a panel of Italian dependent workers observed between 1986 and 1991. We use an employer-employee linked panel of 30167 workers, built from Italian Social Security (INPS) administrative sources. In order to investigate the impact of individual vs. firm characteristics on wage dynamics, we decompose individual wage change 1986-91 in two parts: the mean wage growth observed across firms of origin and firms of destination (the two coincide for the stayers), and the wage premium gained over the mean wage change by movers attributable to their own personal characteristics. Our main findings may be summarized as follows: 1 In general, movers do better than stayers at young age (20-30), but the difference tends to vanish as age progresses; 2 mover-stayer differentials are larger among white-collars than blue-collars, in line with the higher variance of earnings of the former; 3 total wage growth is driven by the wage - firm size positive correlation only for the blue-collars: job-switches from small to large firms often yield substantial pay improvements relative to stayers; job switches from large to small size often end up in wage cuts. For the white-collars, however, job changes in either direction tend to improve onÈs position relative to stayers; 4 there is a quasi-reverse pattern on the individual premiums of the blue-collars (switches from small to large carry negative premiums, from large to small positive). This is likely to be a consequence of firm-based wage policies, the impact of which by far exceeds that attributable to individual characteristics; 5 personal characteristics contribute, instead, to determine the white-collars' individual premiums. Job changes of adult and mature workers, presumably endowed with skills and experience, result in sizeable wage gains; 6 all workers employed at firms that either close down or go through drastic employment cuts during the observation period suffer wage losses; 7 prolonged unemployment spells have somewhat of a negative impact on the wage growth of white-collar employees (up to 5 p.p.), almost none on the blue-collars; 8 a certain amount of job-switching has a positive effect on the wage growth of the younger white-collars. If job changes become too frequent, however, its positive impact vanishes; 9 we find a rather strong effect of initial conditions on the wage profile of blue-collar employees, and almost none on the white-collars'; 10 there is evidence of a trade-off between job security and pay in concomitance with a job-to-job switch. When adverse shocks are in sight - as was the beginning of the Nineties - it is reasonable that people may leave their current position, if it is perceived at risk, giving up some pay for longer expected tenure, or may choose to accept a higher pay with a less reliable (i.e. more exposed to short-term fluctuations) employer. At the end of the paper I argue that there are reasons to believe that the extent of labor market segmentation may be increasing in the EU as a consequence of policies aiming at helping entry of youth into employment.

Relativistic model of hidden bottom tetraquarks

The relativistic model of the ground state and excited heavy tetraquarks with hidden bottom is formulated within the diquark-antidiquark picture. The diquark structure is taken into account by calculating the diquark-gluon vertex in terms of the diquark wave functions. Predictions for the masses of bottom counterparts to the charm tetraquark candidates are given.Comment: 6 page