Triggering with the ALICE TRD

We discuss how a level-1 trigger, about 8 us after a hadron-hadron collision, can be derived from the Transition Radiation Detector (TRD) in A Large Ion Collider Experiment (ALICE) at the LHC. Chamber-wise track segments from fast on-detector reconstruction are read out with position, angle and electron likelihood. In the Global Tracking Unit up to 6 tracklets from a particle traversing the detector layers are matched and used for the reconstruction of transverse momentum and electron identification. Such tracks form the basis for versatile and flexible trigger conditions, e.g. single high-pt hadron, single high-pt electron, di-electron (J/Psi, Upsilon) and at least n close high-pt tracks (jet). The need for low-latency on-line reconstruction poses challenges on the detector operation. The calibration for gain (pad-by-pad) and drift velocity must be applied already in the front-end electronics. Due to changes in pressure and gas composition an on-line monitoring and feedback loop for these parameters is required. First experiences on the performance were gathered from triggering in cosmic and pp runs.Comment: 6 pages, 10 figure

The ALICE Transition Radiation Detector: status and perspectives for Run II

The ALICE Transition Radiation Detector contributes to the tracking, particle identification, and triggering capabilities of the experiment. It is composed of six layers of multi-wire proportional chambers, each of which is preceded by a radiator and a Xe/CO$_2$-filled drift volume. The signal is sampled in timebins of 100~ns over the drift length which allows for the reconstruction of chamber-wise track segments, both online and offline. The particle identification is based on the specific energy loss of charged particles and additional transition radiation photons, the latter being a signature for electrons. The detector is segmented into 18 sectors, of which 13 were installed in Run I. The TRD was included in data taking since the LHC start-up and was successfully used for electron identification and triggering. During the Long Shutdown 1, the detector was completed and now covers the full azimuthal acceptance. Furthermore, the readout and trigger components were upgraded. When data taking was started for \runii{}, their performance fulfilled the expectations

Vulnerability to Poverty and Vulnerability to Climate Change : Conceptual Framework, Measurement and Synergies in Policy

This paper attempts to compare the concepts and metrics related to vulnerability notion as used in the poverty literature with those in the filed of climate change. Such comparison could shed light on the understanding of the perceived and real differences between the two fields and also help to identify possible policy synergies between the climate change and poverty communities. The analysis shows that while vulnerability concepts in both the disciplines are defendable, broader policy relevant statements about vulnerability could be made if the analysis clearly identifies three primitives introduced in Ionescu et al. (2006) namely, the entity that is vulnerable, the stimulus due to which the entity is vulnerable, and the preference criteria on the outcome of concern. The analysis shows significant similarities between the two fields in terms of vulnerability measurement. The link between the vulnerability metrics in the two fields can be established through the introduction of sensitivity notion. The analysis also shows that the vulnerability metrics in both fields demand a stricter restriction (namely, complete reorder) on preference criteria on the outcome(s) of concern. The analysis identifies two issues that, if addressed, could create synergies between vulnerability assessments in the climate change and the poverty communities. First, the climate change community could benefit from exploring a notion analogous to that of poverty. In development policy, the notion of poverty enables one to recognise that there is a need to focus not only on people who are likely to become poor due to some exogenous input, but also on those who already are poor (and may become even poorer). Second, it would be interesting to explore the analogous concepts of mitigation and adaptive capacity in poverty research. Similar to their use in climate research and policy, the analysis of these concepts could lead to the more explicit consideration of the multidimensional nature of both causes and outcomes of poverty, as well as of the multiple time scales on which these occur.vulnerability, poverty, Climate change, Adaptation

The Effect of Fluctuations on the QCD Critical Point in a Finite Volume

We investigate the effect of a finite volume on the critical behavior of the theory of the strong interaction (QCD) by means of a quark-meson model for two quark flavors. In particular, we analyze the effect of a finite volume on the location of the critical point in the phase diagram existing in our model. In our analysis, we take into account the effect of long-range fluctuations with the aid of renormalization group techniques. We find that these quantum and thermal fluctuations, absent in mean-field studies, play an import role for the dynamics in a finite volume. We show that the critical point is shifted towards smaller temperatures and larger values of the quark chemical potential if the volume size is decreased. This behavior persists for antiperiodic as well as periodic boundary conditions for the quark fields as used in many lattice QCD simulations.Comment: 9 pages, 2 figures, 1 tabl

The gravitational cat on the Cauchy horizon

We show that the stress tensor of a real scalar quantum field on Reissner-Nordstr{\"o}m-deSitter spacetime exhibits correlations over macroscopic distances near the Cauchy horizon. These diverge as the Cauchy horizon is approached and are universal, i.e., state-independent. This signals a breakdown of the semi-classical approximation near the Cauchy horizon. We also investigate the effect of turning on a charge of the scalar field and consider the correlation of the stress tensor between the two poles of the Cauchy horizon of Kerr-de Sitter spacetime.Comment: 6 pages, 6 figure

Functional Dependencies for Object Databases: Motivation and Axiomatization

Object identification by abstract identifiers should be considered as a modeling and not as a database concept. This means that object identifiers are not appropriate for the access to specific objects using a database language. In this paper we discuss how the relational concept of a functional dependency can be adapted to object databases in order to get more convenient ways of accessing objects. Graph based object functional dependencies are proposed as a means to specify constraints between attributes and object types of an object schema. Value based identification criteria can be defined using a special type of object functional dependencies. Different definitions of satisfaction are given for these constraints, based on a so-called validation relation, and their relationships are investigated. These definitions are related to different forms of identification. Using the strongest notion of satisfaction, inference rules for the derivation of new dependencies are discussed with emphasis on the characteristics of rules combining two dependencies, like the transitivity rule. In addition to generalized relational rules further rules are needed, mainly concerned with transition from the object type level to the attribute level and vice versa