Geometric Universality of Currents

We discuss a non-equilibrium statistical system on a graph or network. Identical particles are injected, interact with each other, traverse, and leave the graph in a stochastic manner described in terms of Poisson rates, possibly dependent on time and instantaneous occupation numbers at the nodes of the graph. We show that under the assumption of constancy of the relative rates, the system demonstrates a profound statistical symmetry, resulting in geometric universality of the statistics of the particle currents. This phenomenon applies broadly to many man-made and natural open stochastic systems, such as queuing of packages over the internet, transport of electrons and quasi-particles in mesoscopic systems, and chains of reactions in bio-chemical networks. We illustrate the utility of our general approach using two enabling examples from the two latter disciplines.Comment: 15 pages, 5 figure

Microscopic structure of travelling wave solutions in a class of stochastic interacting particle systems

We obtain exact travelling wave solutions for three families of stochastic one-dimensional nonequilibrium lattice models with open boundaries. These solutions describe the diffusive motion and microscopic structure of (i) of shocks in the partially asymmetric exclusion process with open boundaries, (ii) of a lattice Fisher wave in a reaction-diffusion system, and (iii) of a domain wall in non-equilibrium Glauber-Kawasaki dynamics with magnetization current. For each of these systems we define a microscopic shock position and calculate the exact hopping rates of the travelling wave in terms of the transition rates of the microscopic model. In the steady state a reversal of the bias of the travelling wave marks a first-order non-equilibrium phase transition, analogous to the Zel'dovich theory of kinetics of first-order transitions. The stationary distributions of the exclusion process with $n$ shocks can be described in terms of $n$-dimensional representations of matrix product states.Comment: 27 page

The optical/X-ray connection: ICM iron content and galaxy optical luminosity in 20 galaxy clusters

X-ray observations of galaxy clusters have shown that the intra-cluster gas has iron abundances of about one third of the solar value. These observations also show that part (if not all) of the intra-cluster gas metals were produced within the member galaxies. We present a systematic analysis of 20 galaxy clusters to explore the connection between the iron mass and the total luminosity of early-type and late-type galaxies, and of the brightest cluster galaxies (BCGs). From our results, the intra-cluster medium (ICM) iron mass seems to correlate better with the luminosity of the BCGs than with that of the red and blue galaxy populations. As the BCGs cannot produce alone the observed amount of iron, we suggest that ram-pressure plus tidal stripping act together to enhance, at the same time, the BCG luminosities and the iron mass in the ICM. Through the analysis of the iron yield, we have also estimated that SN Ia are responsible for more than 50% of the total iron in the ICM. This result corroborates the fact that ram-pressure contributes to the gas removal from galaxies to the inta-cluster medium, being very efficient for clusters in the temperature range 2 < kT (keV)< 10Comment: Accepted for publication in MNRAS (11 pg, 9 figures and 3 tables

On the Two Species Asymmetric Exclusion Process with Semi-Permeable Boundaries

We investigate the structure of the nonequilibrium stationary state (NESS) of a system of first and second class particles, as well as vacancies (holes), on L sites of a one-dimensional lattice in contact with first class particle reservoirs at the boundary sites; these particles can enter at site 1, when it is vacant, with rate alpha, and exit from site L with rate beta. Second class particles can neither enter nor leave the system, so the boundaries are semi-permeable. The internal dynamics are described by the usual totally asymmetric exclusion process (TASEP) with second class particles. An exact solution of the NESS was found by Arita. Here we describe two consequences of the fact that the flux of second class particles is zero. First, there exist (pinned and unpinned) fat shocks which determine the general structure of the phase diagram and of the local measures; the latter describe the microscopic structure of the system at different macroscopic points (in the limit L going to infinity in terms of superpositions of extremal measures of the infinite system. Second, the distribution of second class particles is given by an equilibrium ensemble in fixed volume, or equivalently but more simply by a pressure ensemble, in which the pair potential between neighboring particles grows logarithmically with distance. We also point out an unexpected feature in the microscopic structure of the NESS for finite L: if there are n second class particles in the system then the distribution of first class particles (respectively holes) on the first (respectively last) n sites is exchangeable.Comment: 28 pages, 4 figures. Changed title and introduction for clarity, added reference

Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902

We present a study of the population of bright early-type dwarf galaxies in the multiple-cluster system Abell 901/902. We use data from the STAGES survey and COMBO-17 to investigate the relation between the color and structural properties of the dwarfs and their location in the cluster. The definition of the dwarf sample is based on the central surface brightness and includes galaxies in the luminosity range -16 >= M_B >~-19 mag. Using a fit to the color magnitude relation of the dwarfs, our sample is divided into a red and blue subsample. We find a color-density relation in the projected radial distribution of the dwarf sample: at the same luminosity dwarfs with redder colors are located closer to the cluster centers than their bluer counterparts. Furthermore, the redder dwarfs are on average more compact and rounder than the bluer dwarfs. These findings are consistent with theoretical expectations assuming that bright early-type dwarfs are the remnants of transformed late-type disk galaxies involving processes such as ram pressure stripping and galaxy harassment. This indicates that a considerable fraction of dwarf elliptical galaxies in clusters are the results of transformation processes related to interactions with their host cluster.Comment: 12 pages, 8 figures, accepted for publication in A&A, typo corrected in abstrac

Spatial variations of the optical galaxy luminosity functions and red sequences in the Coma cluster: clues to its assembly history

Clusters of galaxies are believed to be at the intersections of cosmological filaments and to grow by accreting matter from these filaments. Such continuous infall has major consequences not only on clusters but also on the physics of cluster galaxies. Faint galaxies are particularly interesting as they are very sensitive to environmental effects, and may have a different behaviour from that of bright galaxies. The aim of this paper is to sample the Coma cluster building history, based on the analysis of galaxy luminosity functions and red sequences in the Color Magnitude Relation down to faint magnitudes, which are privileged tools for this purpose. The present analysis is based on deep (R~24), wide (~0.5 deg2) multiband (BVRI Vega system) images of the Coma cluster obtained with the CFH12K camera at the CFHT. We have derived LFs and CMRs in twenty 10x10 arcmin2 regions and in larger regions. In all photometric bands, we found steeply rising LFs in the north-northeast half of the cluster (due to early type galaxies at bright magnitudes and due to late type galaxies at the faint end), and much flatter LFs in the south-southwest region. Although the fine behaviour of the CMR RS is different in these two regions, a good agreement is found in general between the RS computed for faint and for bright galaxies. All these results can be interpreted consistently in the framework of the building up process previously proposed. The Northern Coma area is a relatively quiescent region while the southern area experiences several infalls.Comment: To be published in A&A, several figures in jpg format, full resolution figures and paper available at http://cencosw.oamp.fr/ under the Coma page. The lacking figures are available at the same adress. Updated CFHT acknowledgements and aa forma

The Ks-band Tully-Fisher Relation - A Determination of the Hubble Parameter from 218 ScI Galaxies and 16 Galaxy Clusters

The value of the Hubble Parameter (H0) is determined using the morphologically type dependent Ks-band Tully-Fisher Relation (K-TFR). The slope and zero point are determined using 36 calibrator galaxies with ScI morphology. Calibration distances are adopted from direct Cepheid distances, and group or companion distances derived with the Surface Brightness Fluctuation Method or Type Ia Supernova. Distances are determined to 16 galaxy clusters and 218 ScI galaxies with minimum distances of 40.0 Mpc. From the 16 galaxy clusters a weighted mean Hubble Parameter of H0=84.2 +/-6 km s-1 Mpc-1 is found. From the 218 ScI galaxies a Hubble Parameter of H0=83.4 +/-8 km s-1 Mpc-1 is found. When the zero point of the K-TFR is corrected to account for recent results that find a Large Magellanic Cloud distance modulus of 18.39 +/-0.05 a Hubble Parameter of 88.0 +/-6 km s-1 Mpc-1 is found. A comparison with the results of the Hubble Key Project (Freedman et al 2001) is made and discrepancies between the K-TFR distances and the HKP I-TFR distances are discussed. Implications for Lamda-CDM cosmology are considered with H0=84 km s-1 Mpc-1. (Abridged)Comment: 37 pages including 12 tables and 7 figures. Final version accepted for publication in the Journal of Astrophysics & Astronom

To which countries do European psychiatric trainees want to move to and why?

publisher: Elsevier articletitle: To which countries do European psychiatric trainees want to move to and why? journaltitle: European Psychiatry articlelink: http://dx.doi.org/10.1016/j.eurpsy.2017.06.010 content_type: article copyright: © 2017 Elsevier Masson SAS. All rights reserved.publisher: Elsevier articletitle: To which countries do European psychiatric trainees want to move to and why? journaltitle: European Psychiatry articlelink: http://dx.doi.org/10.1016/j.eurpsy.2017.06.010 content_type: article copyright: © 2017 Elsevier Masson SAS. All rights reserved.BACKGROUND: There is a shortage of psychiatrists worldwide. Within Europe, psychiatric trainees can move between countries, which increases the problem in some countries and alleviates it in others. However, little is known about the reasons psychiatric trainees move to another country. METHODS: Survey of psychiatric trainees in 33 European countries, exploring how frequently psychiatric trainees have migrated or want to migrate, their reasons to stay and leave the country, and the countries where they come from and where they move to. A 61-item self-report questionnaire was developed, covering questions about their demographics, experiences of short-term mobility (from 3 months up to 1 year), experiences of long-term migration (of more than 1 year) and their attitudes towards migration. RESULTS: A total of 2281 psychiatric trainees in Europe participated in the survey, of which 72.0% have 'ever' considered to move to a different country in their future, 53.5% were considering it 'now', at the time of the survey, and 13.3% had already moved country. For these immigrant trainees, academic was the main reason they gave to move from their country of origin. For all trainees, the overall main reason for which they would leave was financial (34.4%), especially in those with lower (2500€) incomes, personal reasons were paramount (44.5%). CONCLUSIONS: A high number of psychiatric trainees considered moving to another country, and their motivation largely reflects the substantial salary differences. These findings suggest tackling financial conditions and academic opportunities

Experimental traumatic brain injury

Traumatic brain injury, a leading cause of death and disability, is a result of an outside force causing mechanical disruption of brain tissue and delayed pathogenic events which collectively exacerbate the injury. These pathogenic injury processes are poorly understood and accordingly no effective neuroprotective treatment is available so far. Experimental models are essential for further clarification of the highly complex pathology of traumatic brain injury towards the development of novel treatments. Among the rodent models of traumatic brain injury the most commonly used are the weight-drop, the fluid percussion, and the cortical contusion injury models. As the entire spectrum of events that might occur in traumatic brain injury cannot be covered by one single rodent model, the design and choice of a specific model represents a major challenge for neuroscientists. This review summarizes and evaluates the strengths and weaknesses of the currently available rodent models for traumatic brain injury