Generalised hyperbolicity in spacetimes with string-like singularities

In this paper we present well-posedness results of the wave equation in $H^{1}$ for spacetimes that contain string-like singularities. These results extend a framework able to characterise gravitational singularities as obstruction to the dynamics of test fields rather than point particles. In particular, we discuss spacetimes with cosmic strings and the relation of our results to the Strong Cosmic Censorship Conjecture.Comment: Accepted for publication in Classical and Quantum Gravit

The legal form of labour conflicts and their time persistence: an empirical analysis with a large firms' panel

Using a panel of large firms from Spain, we check the relative time persistence of different types of labour conflicts such as strikes, collective conflicts, lockouts and other conflicts with lost working hours but without the previous stated legal forms for labour conflicts. We present random-effects probit estimations comparing observations with each type of conflicts with the same set of observations without any type of conflict. The results show that no legal form labour conflicts do not have long-term persistence (persistence is only in the short-term, from quarter to quarter), and the other types of conflicts suffer short and long-term persistence of confliction at the firm level, corresponds to strikes the higher size of both types of persistence. As short and long term persistence of strikes have almost the same size these results do not support asymmetric information theories of strike.Strike; labour conflict; time persistence; asymmetric information

Hypernuclear Physics at PANDA

Hypernuclear research will be one of the main topics addressed by the PANDA experiment at the planned Facility for Anti-proton and Ion Research FAIR at Darmstadt, Germany. A copious production of Xi-hyperons at a dedicated internal target in the stored anti-proton beam is expected, which will enable the high-precision gamma-spectroscopy of double strange systems for the first time. In addition to the general purpose PANDA setup, the hypernuclear experiments require an active secondary target of silicon layers and absorber material as well as high purity germanium (HPGe) crystals as gamma-detectors. The design of the setup and the development of these detectors is progressing: a first HPGe crystal with a new electromechanical cooling system was prepared and the properties of a silicon strip detector as a prototype to be used in the secondary target were studied. Simultaneously to the hardware projects, detailed Monte Carlo simulations were performed to predict the yield of particle stable hypernuclei. With the help of the Monte Carlo a procedure for Lambda-Lambda-hypernuclei identification by the detection and correlation of the weak decay pions was developed.Comment: prepared for the International Conference on Exotic Atoms and Related Topics (EXA2011), Vienna, Sept. 5-9, 201

Ancillary Documentation on the Union Army Migration Data set (UMAD)

migration; economic history; economics of aging

The Effect of Spatial Curvature on the Classical and Quantum Strings

We study the effects of the spatial curvature on the classical and quantum string dynamics. We find the general solution of the circular string motion in static Robertson-Walker spacetimes with closed or open sections. This is given closely and completely in terms of elliptic functions. The physical properties, string length, energy and pressure are computed and analyzed. We find the {\it back-reaction} effect of these strings on the spacetime: the self-consistent solution to the Einstein equations is a spatially closed $(K>0)$ spacetime with a selected value of the curvature index $K$ (the scale f* is normalized to unity). No self-consistent solutions with $K\leq 0$ exist. We semi-classically quantize the circular strings and find the mass $m$ in each case. For $K>0,$ the very massive strings, oscillating on the full hypersphere, have $m^2\sim K n^2\;\;(n\in N_0)$ {\it independent} of $\alpha'$ and the level spacing {\it grows} with $n,$ while the strings oscillating on one hemisphere (without crossing the equator) have $m^2\alpha'\sim n$ and a {\it finite} number of states $N\sim 1/(K\alpha').$ For $K<0,$ there are infinitely many string states with masses $m\log m\sim n,$ that is, the level spacing grows {\it slower} than $n.$ The stationary string solutions as well as the generic string fluctuations around the center of mass are also found and analyzed in closed form.Comment: 30 pages Latex + three tables and five figures (not included

Heat current through an artificial Kondo impurity beyond linear response

We investigate the heat current of a strongly interacting quantum dot in the presence of a voltage bias in the Kondo regime. Using the slave- boson mean-field theory, we discuss the behavior of the energy flow and the Joule heating. We find that both contributions to the heat current dis- play interesting symmetry properties under reversal of the applied dc bias. We show that the symmetries arise from the behavior of the dot trans- mission function. Importantly, the transmission probability is a function of both energy and voltage. This allows us to analyze the heat current in the nonlinear regime of transport. We observe that nonlinearities ap- pear already for voltages smaller than the Kondo temperature. Finally, we suggest to use the contact and electric symmetry coefficients as a way to measure pure energy currents.Comment: 9 pages, 2 figures, proceeding of the Low Temperature Physics Conferenc