3,367 research outputs found

    The Association between Hostile Attribution Bias, Social Intelligence, and Relational Aggression in Detained Boys

    Get PDF
    Research on factors that contribute to the forms and functions of aggression (reactive, proactive, relational, and overt) is important for informing intervention efforts with aggressive youth. Previous research shows that aggressive youth often have cognitive and social deficits associated with their aggressive behavior. For example, aggressive youth may exhibit deficits in social variables such as social intelligence (i.e., the understanding of behaviors of people and ability to predict outcomes of situations). Hypothetically, this lack of social intelligence may be related to how youth interpret social situations, and could conceivably lead to hostile attributional bias, or the tendency to interpret ambiguous stimuli as hostile. The main purpose of this study was to examine whether HAB mediated the relationship between social intelligence and reactive relational aggression in a sample of detained adolescent boys (ages 12-18). The results failed to support this hypothesis. Supplemental analyses explored whether HAB moderated the relationship between social intelligence and the subtypes of aggression, but results were not consistent with this hypothesis

    Dissecting the Gravitational Lens B1608+656. II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State

    Get PDF
    Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the "time-delay distance" to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (i) new, deep Hubble Space Telescope (HST) observations, (ii) a new velocity dispersion measurement of 260+/-15 km/s for the primary lens galaxy, and (iii) an updated study of the lens' environment. When modeling the stellar dynamics of the primary lens galaxy, the lensing effect, and the environment of the lens, we explicitly include the total mass distribution profile logarithmic slope gamma' and the external convergence kappa_ext; we marginalize over these parameters, assigning well-motivated priors for them, and so turn the major systematic errors into statistical ones. The HST images provide one such prior, constraining the lens mass density profile logarithmic slope to be gamma'=2.08+/-0.03; a combination of numerical simulations and photometric observations of the B1608+656 field provides an estimate of the prior for kappa_ext: 0.10 +0.08/-0.05. This latter distribution dominates the final uncertainty on H_0. Compared with previous work on this system, the new data provide an increase in precision of more than a factor of two. In combination with the WMAP 5-year data set, we find that the B1608+656 data set constrains the curvature parameter to be -0.031 < Omega_k < 0.009 (95% CL), a level of precision comparable to that afforded by the current Type Ia SNe sample. Asserting a flat spatial geometry, we find that, in combination with WMAP, H_0 = 69.7 +4.9/-5.0 km/s/Mpc and w=-0.94 +0.17/-0.19 (68% CL), suggesting that the observations of B1608+656 constrain w as tightly as do the current Baryon Acoustic Oscillation data. (abridged)Comment: 24 pages, 8 figures, revisions based on referee's comments, accepted for publication in Ap

    The Environments of Low and High Luminosity Radio Galaxies at Moderate Redshifts

    Full text link
    In the local Universe, high-power radio galaxies live in lower density environments than low-luminosity radio galaxies. If this trend continues to higher redshifts, powerful radio galaxies would serve as efficient probes of moderate redshift groups and poor clusters. Photometric studies of radio galaxies at 0.3 < z < 0.5 suggest that the radio luminosity-environment correlation disappears at moderate redshifts, though this could be the result of foreground/background contamination affecting the photometric measures of environment. We have obtained multi-object spectroscopy of in the fields of 14 lower luminosity (L_1.4GHz 1.2x10^25 W/Hz) radio galaxies at z ~ 0.3 to spectroscopically investigate the link between the environment and the radio luminosity of radio galaxies at moderate redshifts. Our results support the photometric analyses; there does not appear to be a correlation between the luminosity of a radio galaxy and its environment at moderate redshifts. Hence, radio galaxies are not efficient signposts for group environments at moderate redshifts.Comment: 7 pages, 9 figures, Accepted for publication in A

    Luminous Satellites II: Spatial Distribution, Luminosity Function and Cosmic Evolution

    Full text link
    We infer the normalization and the radial and angular distributions of the number density of satellites of massive galaxies (log10[Mh/M]>10.5\log_{10}[M_{h}^*/M\odot]>10.5) between redshifts 0.1 and 0.8 as a function of host stellar mass, redshift, morphology and satellite luminosity. Exploiting the depth and resolution of the COSMOS HST images, we detect satellites up to eight magnitudes fainter than the host galaxies and as close as 0.3 (1.4) arcseconds (kpc). Describing the number density profile of satellite galaxies to be a projected power law such that P(R)\propto R^{\rpower}, we find \rpower=-1.1\pm 0.3. We find no dependency of \rpower on host stellar mass, redshift, morphology or satellite luminosity. Satellites of early-type hosts have angular distributions that are more flattened than the host light profile and are aligned with its major axis. No significant average alignment is detected for satellites of late-type hosts. The number of satellites within a fixed magnitude contrast from a host galaxy is dependent on its stellar mass, with more massive galaxies hosting significantly more satellites. Furthermore, high-mass late-type hosts have significantly fewer satellites than early-type galaxies of the same stellar mass, likely a result of environmental differences. No significant evolution in the number of satellites per host is detected. The cumulative luminosity function of satellites is qualitatively in good agreement with that predicted using subhalo abundance matching techniques. However, there are significant residual discrepancies in the absolute normalization, suggesting that properties other than the host galaxy luminosity or stellar mass determine the number of satellites.Comment: 23 pages, 12 figures, Accepted for publication in the Astrophysical Journa

    A shrinking Compact Symmetric Object: J11584+2450?

    Get PDF
    We present multi-frequency multi-epoch Very Long Baseline Array (VLBA) observations of J11584+2450. These observations clearly show this source, previously classified as a core-jet, to be a compact symmetric object (CSO). Comparisons between these new data and data taken over the last 9 years shows the edge brightened hot spots retreating towards the core (and slightly to the west) at approximately 0.3c. Whether this motion is strictly apparent or actually physical in nature is discussed, as well as possible explanations, and what implications a physical contraction of J11584+2450 would have for current CSO models.Comment: 16 pages, 6 figures, 5 tables. Accepted for publication in Ap

    Mass along the Line of Sight to the Gravitational Lens B1608+656: Galaxy Groups and Implications for H_0

    Get PDF
    We report the discovery of four groups of galaxies along the line of sight to the B1608+656 gravitational lens system. One group is at the redshift of the primary lensing galaxy (z = 0.631) and appears to have a low mass, with eight spectroscopically confirmed members and an estimated velocity dispersion of 150 ± 60 km s^(-1). The three other groups are in the foreground of the lens. These groups contain ~10 confirmed members each and are located at redshifts of 0.265, 0.426, and 0.52. Two of the three additional groups are centered roughly on the lens system, while the third is centered ~1' south of the lens. We investigate the effect of each of the four groups on the gravitational lensing potential of the B1608+656 system, with a particular focus on the implications for the value of H_0 derived from this system. We find that each group provides an external convergence of ~0.005-0.060, depending on the assumptions made in the calculation. For the B1608+656 system, the stellar velocity dispersion of the lensing galaxy has been measured, thus breaking the mass sheet degeneracy due to the group that is physically associated with the lens. The effect of the other groups along the line of sight can be folded into the overall uncertainties due to large-scale structure (LSS) along the line of sight. Because B1608+656 appears to lie along an overdense line of sight, the LSS will cause the measurement of H_0 to be biased high for this system. This effect could be 5% or greater

    adjuvant mitotane for adrenocortical cancer working through uncertainty

    Get PDF
    The Journal of Clinical Endocrinology & Metabolism recently published a commentary by Huang and Fojo (1) offering a skeptical view on the efficacy of mitotane as an adjunctive postsurgical measure in patients with adrenocortical cancer (ACC). Their commentary focused on outlining the limitations of our recent study which indicated that adjuvant mitotane may prolong recurrence-free survival (RFS) in patients with radically resected ACC (2). However, we do not agree with several of their conclusions and believe that it is of interest to present our view for a balanced and comprehensive coverage of this important matter. Inprinciple,weagreewithHuangandFojothatourstudysuffers from the important limitation of a retrospective analysis; thus our investigation should be considered as hypothesis generating and certainly does not provide conclusive evidence. This problem has been clearly acknowledged in the paper, and we cautiously concluded that our study should renew interest in adjuvant therapy, whereas prospective, randomized trials will be needed to confirm the efficacyof adjuvantmitotane treatment (2).However, the rarity of ACC precluded organization of a randomized trial either in an adjuvantsettingor inpatientswithadvancedACC(3).Nonetheless, mitotane has been used for treating patients with ACC since the 1960s and is the only drug approved for ACC by the U.S. Food and Drug Administration and the European Medicines Evaluation Agency (4). In this scenario, a study including all consecutive patients treated postoperatively with mitotane in some centers and all consecutive patients left untreated after operation in other centers is thebestway toobtainexplorativedataon theefficacyofadjuvant mitotane, provided that the two groups are comparable. In our study, in fact, mitotane was recommended on the basis of the treatmentpolicyof thecenter, independentof thecharacteristicsofeither the tumorsor thepatients, and this is amajoradvantageminimizing selection bias as compared with other studies that had less clear treatment assignments (5). The major criticism of Huang and Fojo (1) is that we did not demonstrate any benefit on overall survival (OS) for patients treated adjuvantly. However, this is not correct because the hazard ratio of death of the German cohort of nontreated patients was nonsignificantly higher than mitotane-treated patients in univariate analysis, but the difference became significant in multivariate analysis after adjusting for imbalances in prognostic factors (the German cohort included more patients with stage I and II ACC than the Italian cohort of mitotane-treated patients). Even when we accept that the effect of adjuvant mitotane on OS was less impressive than on RFS, we disagree that prolonging a disease-free status is not a clinically meaningful objective even without extending significantly duration of life. In addition, there is a long-standing debate on the most appropriate endpoint for adjuvant trials, and both OS and RFS have been suggested. Analysis of RFS has the advantage of needing a shorter follow-up and being directly related to the treatment tested. The most important disadvantage of RFS is its close relationship to the frequency and quality of evaluation. Bias in follow-up or ascertainment of outcome in observational retrospective series is well recognized, and we have acknowledged this potential limit of our study. However, the follow-up procedures were highly comparable among the different centers and included imaging evaluation of the chest and abdomen every 6 months until disease progression or the end of the study period (2). Even if survival has to be considered as the reference end-point, it may not be a direct result of the study drug because it may be strongly influenced by subsequent treatments and oncologists are increasingly considering RFS as a valid surrogate for OS (6). However, this relationship has never been demonstrated specifically in ACC patients. Another criticism is derived from an ill-conceived reanalysis of our data. Huang and Fojo (1) aimed at demonstrating that the time interval between ACC recurrence and death is higher in patients treated adjuvantly than patients left untreated after surgery. Thus, they assumed important differences in tumor biology of the different cohorts. This conclusion comes from subtracting median time to recurrence from median survival observed in th

    The Assembly of the Red Sequence at z ~ 1: The Color and Spectral Properties of Galaxies in the Cl1604 Supercluster

    Get PDF
    We investigate the properties of the 525 spectroscopically confirmed members of the Cl1604 supercluster at z ~ 0.9 as part of the Observations of Redshift Evolution in Large Scale Environments survey. In particular, we focus on the photometric, stellar mass, morphological, and spectral properties of the 305 member galaxies of the eight clusters and groups that comprise the Cl1604 supercluster. Using an extensive Keck Low-Resolution Imaging Spectrometer (LRIS)/DEep Imaging Multi-Object Spectrograph (DEIMOS) spectroscopic database in conjunction with ten-band ground-based, Spitzer, and Hubble Space Telescope imaging, we investigate the buildup of the red sequence in groups and clusters at high redshift. Nearly all of the brightest and most massive red-sequence galaxies present in the supercluster environment are found to lie within the bounds of the cluster and group systems, with a surprisingly large number of such galaxies present in low-mass group systems. Despite the prevalence of these red-sequence galaxies, we find that the average cluster galaxy has a spectrum indicative of a star-forming galaxy, with a star formation rate between those of z ~ 1 field galaxies and moderate-redshift cluster galaxies. The average group galaxy is even more active, exhibiting spectral properties indicative of a starburst. The presence of massive, red galaxies and the high fraction of starbursting galaxies present in the group environment suggest that significant processing is occurring in group environments at z ~ 1 and earlier. There is a deficit of low-luminosity red-sequence galaxies in all Cl1604 clusters and groups, suggesting that such galaxies transition to the red sequence at later times. Extremely massive (~10^(12)M_☉) red-sequence galaxies routinely observed in rich clusters at z ~ 0 are also absent from the Cl1604 clusters and groups. We suggest that such galaxies form at later times through merging processes. There are significant populations of transition galaxies at intermediate stellar masses (log(M_*)=10.25-10.75) present in the group and cluster environments, suggesting that this range is important for the buildup of the red-sequence mass function at z ~ 1. Through a comparison of the transitional populations present in the Cl1604 cluster and group systems, we find evidence that massive blue-cloud galaxies are quenched earliest in the most dynamically relaxed systems and at progressively later times in dynamically unrelaxed systems
    corecore