A Long-Lived Accretion Disk Around a Lithium-Depleted Binary T Tauri Star

We present a high dispersion optical spectrum of St 34 and identify the system as a spectroscopic binary with components of similar luminosity and temperature (both M3+/-0.5). Based on kinematics, signatures of accretion, and location on an H-R diagram, we conclude that St 34 is a classical T Tauri star belonging to the Taurus-Auriga T Association. Surprisingly, however, neither component of the binary shows LiI 6708 A, absorption, the most universally accepted criterion for establishing stellar youth. In this uniquely known instance, the accretion disk appears to have survived longer than the lithium depletion timescale. We speculate that the long-lived accretion disk is a consequence of the sub-AU separation companion tidally inhibiting, though not preventing, circumstellar accretion. Comparisons with pre-main sequence evolutionary models imply, for each component of St 34, a mass of 0.37+/-0.08 Msun and an isochronal age of 8+/-3 Myr, which is much younger than the predicted lithium depletion timescale of ~ 25 Myr. Although a distance 38% closer than that of Taurus-Auriga or a hotter temperature scale could reconcile this discrepancy at 21-25 Myr, similar discrepancies in other systems and the implications of an extremely old accreting Taurus-Auriga member suggest instead a possible problem with evolutionary models. Regardless, the older age implied by St 34's depleted lithium abundance is the first compelling evidence for a substantial age spread in this region. Additionally, since St 34's coeval co-members with early M spectral types would likewise fail the lithium test for youth, current membership lists may be incomplete.Comment: 4 pages, including 2 figures. Accepted for publication in ApJ Let

Congener specific analysis of polychlorinated terphenyls

In order to identify and to quantify polychlorinated terphenyls (PCT) in environmental matrices, the chro- matographic behavior of coplanar and non-coplanar congeners was evaluated. A mixture of 16 single PCT congeners was used for method development. Four of these compounds were synthesized for the first time by SUZUKI-coupling reaction. These were p-PCT (2,200 ,6,600 -tetrachloro-, 20 ,3,300 ,4,400 ,50 ,-hexachloro-, 20 ,3,300 ,5,50 ,500 -hexachloro-) and m-PCT (2,200 ,3,300 ,5,500 -hexachloro-). They were characterized by NMR ( 1 H, 13 C) spectroscopy. By means of the new column chromatographic clean-up reported here, a good matrix removal and the separation of the coplanar PCT congeners from the non-coplanar ones was obtained. The recovery rates for all congeners were good for the PCT in different test matrices like fat, charcoal, and soil. The quality of the clean-up, the separation and the recovery rates were determined by GC/MS analysis. The method was applied for the first time to a real sample from a fire accident, where different PCT, obviously formed during the combustion process, were found. The conclusion is drawn that this method is suitable for the analysis of PCT in different environmental samples

An analysis of protests carried out by ships (PCS) : should PCS be regulated by a new IMO instrument?

This paper attempts to analyze protests1 carried out by ships as acts of objection in the exercise of the human right to protest. The purpose of the analysis is to find out whether protests carried out by ships have recognition and legitimation in the maritime industry. Also, considering the one proposal to regulate this maritime activity at the International Maritime Organization (IMO), the analysis attempts to find out whether a new maritime instrument such a Code of Conduct is necessary. This academic exercise takes the reader from the analysis of the reasons why people protest and the right to protest as a human right and its recognition by the international law in general and the IMO in particular to the analysis of the reasons why ships are used to protest, the actors in protests and the most important protest groups currently owning and operating protest ships. In addition, a few cases of protest carried out by ships in maritime zones defined according to the United Nations Convention on the Law of the Sea (UNCLOS), in which the law was breached are analyzed, with the objective to find out what the law of application was and how it was enforced. The conclusions drawn are based on the analytical evidence that protests carried out by ships are legitimate and recognized internationally but hardly accepted by the maritime community due to a distorted perception of the right to protest and due to the weak implementation and enforcement of maritime law in particular on the high seas. Therefore, a Code of Conduct telling protesters not to break the law seems redundant. However, the analysis concludes that risk assessments should be compulsory, not only for protest ships but also for protest targets when protest activities are imminent, especially for direct actions protests; that protest target should learn how to deal with protests through proper guidelines and, finally, that maritime safety and pollution prevention during protests carried out by ships could be improved making compulsory for non-commercial vessels the application of the International Convention for the Safety of Life at Sea (SOLAS), 1974 as amended, the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) as amended, the Maritime Labour Convention (MLC), 2006 and the International Convention on Load Lines (LL), 1966. Further research might explore how to develop guidelines for risk assessments to deal with protests carried out by ships and address the security issue during protests on the high seas

Investigation into the limits of perturbation theory at low Q^2 using HERA deep inelastic scattering data

A phenomenological study of the final combined HERA data on inclusive deep inelastic scattering (DIS) has been performed. The data are presented and investigated for a kinematic range extending from values of the four-momentum transfer, $Q^2$, above 10$^4$ GeV$^2$ down to the lowest values observable at HERA of $Q^2$ = 0.045 GeV$^2$ and Bjorken $x$, $x_{\rm Bj}$ = 6 $\cdot$ 10$^{-7}$. The data are well described by fits based on perturbative quantum chromodynamics (QCD) using collinear factorisation and evolution of the parton densities encompassed in the DGLAP formalism from the highest $Q^2$ down to $Q^2$ of a few GeV$^2$. The Regge formalism can describe the data up to $Q^2 \approx$ 0.65 GeV$^2$. The complete data set can be described by a new fit using the ALLM parameterisation. The region between the Regge and the perturbative QCD regimes is of particular interest.Comment: 38 pages, 13 figure