Small carrion beetles (Coleoptera, Leiodidae, Cholevinae) of Malta

Correspondence article with regards to the presence of the small carrion beetles in Malta.peer-reviewe

Spatial motion of the Magellanic Clouds. Tidal models ruled out?

Recently, Kallivayalil et al. derived new values of the proper motion for the Large and Small Magellanic Clouds (LMC and SMC, respectively). The spatial velocities of both Clouds are unexpectedly higher than their previous values resulting from agreement between the available theoretical models of the Magellanic System and the observations of neutral hydrogen (HI) associated with the LMC and the SMC. Such proper motion estimates are likely to be at odds with the scenarios for creation of the large-scale structures in the Magellanic System suggested so far. We investigated this hypothesis for the pure tidal models, as they were the first ones devised to explain the evolution of the Magellanic System, and the tidal stripping is intrinsically involved in every model assuming the gravitational interaction. The parameter space for the Milky Way (MW)-LMC-SMC interaction was analyzed by a robust search algorithm (genetic algorithm) combined with a fast restricted N-body model of the interaction. Our method extended the known variety of evolutionary scenarios satisfying the observed kinematics and morphology of the Magellanic large-scale structures. Nevertheless, assuming the tidal interaction, no satisfactory reproduction of the HI data available for the Magellanic Clouds was achieved with the new proper motions. We conclude that for the proper motion data by Kallivayalil et al., within their 1-sigma errors, the dynamical evolution of the Magellanic System with the currently accepted total mass of the MW cannot be explained in the framework of pure tidal models. The optimal value for the western component of the LMC proper motion was found to be pm_w(LMC) > -1.3 mas/yr in case of tidal models. It corresponds to the reduction of the Kallivayalil et al. value for pm_w(LMC) by approx. 40% in its magnitude.Comment: ApJ accepted, 17 pages, 4 figure

The Next Great Hope:The Humanitarian Approach to Nuclear Weapons

authorsversionPeer reviewe

The Nonproliferation Complex

For more than four decades the twin goals of nuclear nonproliferation and disarmament have been an almost unchallenged objective of the “international community.” Like drought prevention, or bans on the use of child soldiers, nonproliferation remains a mostly uncontroversial, largely universalistic initiative to which few object. The proponents of nonproliferation are fond of stressing that the Treaty on the Nonproliferation of Nuclear Weapons (NPT) has more signatories than any other arms control treaty. Who would not want to prevent more states from obtaining nuclear weapons? And who, for that matter, would oppose the ideal of a world free of such weapons