The puzzlingly large Ca II triplet absorption in dwarf elliptical galaxies

We present central CaT, PaT, and CaT* indices for a sample of fifteen dwarf elliptical galaxies (dEs). Twelve of these have CaT* ~ 7 A and extend the negative correlation between the CaT* index and central velocity dispersion sigma, which was derived for bright ellipticals (Es), down to 20 < sigma < 55 km/s. For five dEs we have independent age and metallicity estimates. Four of these have CaT* ~ 7 A, much higher than expected from their low metallicities (-1.5 < [Z/H] < -0.5). The observed anti-correlation of CaT* as a function of sigma or Z is in flagrant disagreement with theory. We discuss some of the amendments that have been proposed to bring the theoretical predictions into agreement with the observed CaT*-values of bright Es and how they can be extended to incorporate also the observed CaT*-values of dEs. Moreover, 3 dEs in our sample have CaT* ~ 5 A, as would be expected for metal-poor stellar systems. Any theory for dE evolution will have to be able to explain the co-existence of low-CaT* and high-CaT* dEs at a given mean metallicity. This could be the first direct evidence that the dE population is not homogeneous, and that different evolutionary paths led to morphologically and kinematically similar but chemically distinct objects.Comment: 4 pages, 3 figures, accepted for publication in ApJ Letter

Possible Experience: from Boole to Bell

Mainstream interpretations of quantum theory maintain that violations of the Bell inequalities deny at least either realism or Einstein locality. Here we investigate the premises of the Bell-type inequalities by returning to earlier inequalities presented by Boole and the findings of Vorob'ev as related to these inequalities. These findings together with a space-time generalization of Boole's elements of logic lead us to a completely transparent Einstein local counterexample from everyday life that violates certain variations of the Bell inequalities. We show that the counterexample suggests an interpretation of the Born rule as a pre-measure of probability that can be transformed into a Kolmogorov probability measure by certain Einstein local space-time characterizations of the involved random variables.Comment: Published in: EPL, 87 (2009) 6000

Classical and Quantum Annealing in the Median of Three Satisfiability

We determine the classical and quantum complexities of a specific ensemble of three-satisfiability problems with a unique satisfying assignment for up to N=100 and N=80 variables, respectively. In the classical limit we employ generalized ensemble techniques and measure the time that a Markovian Monte Carlo process spends in searching classical ground states. In the quantum limit we determine the maximum finite correlation length along a quantum adiabatic trajectory determined by the linear sweep of the adiabatic control parameter in the Hamiltonian composed of the problem Hamiltonian and the constant transverse field Hamiltonian. In the median of our ensemble both complexities diverge exponentially with the number of variables. Hence, standard, conventional adiabatic quantum computation fails to reduce the computational complexity to polynomial. Moreover, the growth-rate constant in the quantum limit is 3.8 times as large as the one in the classical limit, making classical fluctuations more beneficial than quantum fluctuations in ground-state searches

Towards a Solution for the Ca II Triplet Puzzle : Results from Dwarf Elliptical Galaxies

We present new estimates of ages and metallicities, based on FORS/VLT optical (4400-5500A) spectroscopy, of 16 dwarf elliptical galaxies (dE's) in the Fornax Cluster and in Southern Groups. These dE's are more metal-rich and younger than previous estimates based on narrow-band photometry and low-resolution spectroscopy. For our sample we find a mean metallicity [Z/H] = -0.33 dex and mean age 3.5 Gyr, consistent with similar samples of dE's in other environments (Local Group, Virgo). Three dE's in our sample show emission lines and very young ages. This suggests that some dE's formed stars until a very recent epoch and were self-enriched by a long star formation history. Previous observations of large near-infrared (~8500A) Ca II absorption strengths in these dE's are in good agreement with the new metallicity estimates, solving part of the so-called Calcium puzzle.Comment: ApJ Letters accepted, 5 pages emulateapj, 2 figure

Marching to a different drummer : a cross-cultural comparison of young adolescents who challenge gender norms

Purpose: Little is known about how gender norms regulate adolescents' lives across different cultural settings. This study aims to illustrate what is considered as violating gender norms for boys and girls in four urban poor sites as well as the consequences that follow the challenging of gender norms. Methods: Data were collected as part of the Global Early Adolescent Study, a 15-country collaboration to explore gender norms and health in early adolescence. The current study analyzed narrative and in-depth interviews conducted in urban poor sites in two middle-income (Shanghai, China; and New Delhi, India) and two high-income countries (Baltimore, U.S.; and Ghent, Belgium). A total of 238 participants, 59 boys and 70 girls aged 11-13 years old and 109 of their parents/guardians (28 male adults and 81 female adults), were interviewed. A thematic analysis was conducted across sites using Atlas. Ti 7.5 software. Results: Findings revealed that although most perceptions and expressions about gender were regulated by stereotypical norms, there was a growing acceptability for girls to wear boyish clothes and engage in stereotypical masculine activities such as playing soccer/football. However, there was no comparable acceptance of boys engaging in traditional feminine behaviors. Across all sites, challenging gender norms was often found to lead to verbal, physical, and/or psychological retribution. Conclusions: While it is sometimes acceptable for young adolescents to cross gender boundaries, once it becomes clear that a behavior is socially defined as typical for the other sex, and the adolescent will face more resistance. Researchers, programmers, and clinicians working in the field of adolescent health need not only attend to those who are facing the consequences of challenging prevailing gender norms, but also to address the environment that fosters exclusion and underscores differences

Effectiveness and tolerability of pegylated interferon alfa-2b in combination with ribavirin for treatment of chronic hepatitis C: the PegIntrust Study

Background and study aims : Large international clinical trials conducted in the past 5 years rapidly improved the treatment of chronic hepatitis C; however, it is unclear whether the advances seen in clinical trials are being paralleled by similar improvements in routine clinical practice. PegIntrust is a Belgian community-based trial evaluating the sustained virological response. Patients and Methods : Observational study of 219 patients receiving pegylated interferon alfa-2b (1.5 mu g/kg/wk) and weight. based ribavirin (800-1200 mg/day) for 48 weeks. Primary study end point was sustained virological response (SVR), defined as undetectable HCV RNA 6 months after the completion of treatment. Results : In total, 108 patients (49.3 %) had undetectable HCV RNA at the end of therapy, 91(41.6%) attaining SVR. Of the 111 patients without an end-of-treatment response, 28 were non-responders, and 21 had virological breakthrough. In total, 134 patients attained early virological response (EVR); 88 (65.7%) of those patients attained SVR. In contrast, 82 (96.5 %) of the 85 patients who did not attain EVR also did not attain SVR. Age, fibrosis score and baseline viral load were identified as important predictors of treatment outcome. The most frequently reported serious adverse events resulting in treatment discontinuation were anemia (n = 10), fatigue/asthenia/malaise (n = 6) and fever (n = 3). Conclusion : Our data indicate that treatment of chronic hepatitis C with PEG-IFN alfa-2b plus weight-based ribavirin results in favourable treatment outcomes in a Belgian cohort of patients treated in community-based clinical practice. (Ada gastroenterol. belg., 2010, 73, 5-11)

Hubble Space Telescope survey of the Perseus Cluster -III: The effect of local environment on dwarf galaxies

We present the results of a Hubble Space Telescope (HST) study of dwarf galaxies in the outer regions of the nearby rich Perseus Cluster, down to M_V = -12, and compare these with the dwarf population in the cluster core from our previous HST imaging. In this paper we examine how properties such as the colour magnitude relation, structure and morphology are affected by environment for the lowest mass galaxies. Dwarf galaxies are excellent tracers of the effects of environment due to their low masses, allowing us to derive their environmentally based evolution, which is more subtle in more massive galaxies. We identify 11 dwarf elliptical (dE) and dwarf spheroidal (dSph) galaxies in the outer regions of Perseus, all of which are previously unstudied. We measure the (V-I)_0 colours of our newly discovered dEs, and find that these dwarfs lie on the same red sequence as those in the cluster core. The morphologies of these dwarfs are examined by quantifying their light distributions using CAS parameters, and we find that dEs in the cluster outskirts are on average more disturbed than those in the core, with =0.13\pm0.09 and =0.18\pm0.08, compared to =0.02\pm0.04, =0.01\pm0.07 for those in the core. Based on these results, we infer that these objects are ``transition dwarfs'', likely in the process of transforming from late-type to early type galaxies as they infall into the cluster, with their colours transforming before their structures. When we compare the number counts for both the core and outer regions of the cluster, we find that below M_V = -12, the counts in the outer regions of the cluster exceed those in the core. This is evidence that in the very dense region of the cluster, dwarfs are unable to survive unless they are sufficiently massive to prevent their disruption by the cluster potential and interactions with other galaxies.Comment: 14 pages, 11 figures. MNRAS accepte

Formation and Evolution of Dwarf Elliptical Galaxies - II. Spatially resolved star-formation histories

We present optical VLT spectroscopy of 16 dwarf elliptical galaxies (or dEs) comparable in mass to NGC 205, and belonging to the Fornax cluster and to nearby groups of galaxies. Using ULySS and STECKMAP, we derive radial profiles of the SSP-equivalent ages, metallicities and star-formation histories. The old stellar population of the dEs, which dominates their mass, is likely coeval with that of massive ellipticals or bulges, but the star formation efficiency is lower. Important intermediate age (1-5 Gyr) populations, and frequently tails of star formation until recent times are detected. These histories are reminiscent of their lower mass dSph counterparts of the Local Group. Most galaxies (10/16) show significant metallicity gradients, with metallicity declining by 0.5 dex over one half-light radius on average. These gradients are already present in the old population. The flattened (or discy), rotating objects (6/16) have flat metallicity profiles. This may be consistent with a distinct origin for these galaxies or it may be due to their geometry. The central SSP-equivalent age varies between 1 and 6 Gyr, with the age slowly increasing with radius in the vast majority of objects. The group and cluster galaxies have similar radial gradients and star-formation histories. The strong and old metallicity gradients place important constraints on the possible formation scenarios of dEs. Numerical simulations of the formation of spherical low-mass galaxies reproduce these gradients, but they require a longer time for them to build up. A gentle depletion of the gas, by ram-pressure stripping or starvation, could drive the gas-rich, star-forming progenitors to the present dEs.Comment: 21 pages, 9 figures. Accepted in MNRA

Generation of Intrinsic Vibrational Gap Modes in Three-Dimensional Ionic Crystals

The existence of anharmonic localization of lattice vibrations in a perfect 3-D diatomic ionic crystal is established for the rigid-ion model by molecular dynamics simulations. For a realistic set of NaI potential parameters, an intrinsic localized gap mode vibrating in the [111] direction is observed for fcc and zinc blende lattices. An axial elastic distortion is an integral feature of this mode which forms more readily for the zinc blende than for the fcc structure. Molecular dynamics simulations verify that in each structure this localized mode may be stable for at least 200 cycles.Comment: 5 pages, 4 figures, RevTeX, using epsf.sty. To be published in Phys. Rev. B. Also available at http://www.msc.cornell.edu/~kiselev