The Distance to the Coma Cluster from Surface Brightness Fluctuations

We report on the first determination of the distance to the Coma Cluster based on surface brightness fluctuation (SBF) measurements obtained from Hubble Space Telescope WFPC2 observations of the bright E0 galaxy NGC 4881 in the Coma Cluster and ground-based observations of the standard E1 galaxy NGC 3379 in the Leo-I group. Relative distances based on the I-band fluctuation magnitude, I(SBF), are strongly dependent on metallicity and age of the stellar population. However, the radial changes in the stellar populations of the two giant ellipticals, NGC 3379 and NGC 4881, are well described by published Mg_2 gradients, and the ground-based measurements of I(SBF) at several radial points in NGC 3379 are used to calibrate I(SBF) in terms of the Mg_2 index. The distance to NGC 3379, assumed to be identical to the average SBF distance of the Leo-I group, is combined with the new SBF measurements of NGC 4881 to obtain a Coma Cluster distance of 102+-14 Mpc. Combining this distance with the cosmic recession velocity of Coma (7186+-428 km/s), we find the Hubble constant to be H_0 = 71+-11 km/s/Mpc.Comment: 12 pages, LaTex, includes aaspp4.sty and 3 eps figures. To appear in ApJ Letter

Graphic Katrina: Disaster Capitalism, Tourism Gentrification and the Affect Economy in Josh Neufelds's A.D.: New Orleans After the Deluge (2009)

This article explores the ways in which Josh Neufeld’s documentary comic, A.D.: New Orleans After the Deluge, which was published first online from 2007 to 2008 and then collected in book form in 2009, offers a radical visual commentary on the processes of disaster capitalism and tourism gentrification that have reshaped New Orleans since Hurricane Katrina in 2005. Whilst A.D.’s biblical imagery evokes the proto-corporate language of the ‘blank canvas’ in order to critique regimes of disaster capitalism, its vertical multi-scalar perspectives meanwhile resist the racism of media coverage of the event. Through colouring and other aesthetic choices, the comic also challenges the subsequent propagation of an ‘authentic image’ of New Orleans that promotes tourism gentrification. Where previous critics have emphasised the emotional appeal A.D.’s makes on its readers, I instead discuss the comic’s identification of the structural conditions that have violently impacted the city’s most marginalised inhabitants. Nevertheless, the article qualifies these contentions by acknowledging that A.D. also contributes to an ‘affect economy’ that has exacerbated the privatisation of previously public infrastructure and social services, often to the detriment of pre-Katrina residents simply trying to return to their city

The bright galaxy population of five medium redshift clusters. I. Color-Magnitude Relation, Blue Fractions and Visual Morphology

Using data of five clusters of galaxies within the redshift range 0.15 $\leq$ z $\leq$ 0.25, imaged with the Nordic Optical Telescope (NOT) in the central $\approx$ 1 Mpc$^2$ in very good seeing conditions, we have performed an exhaustive inspection of their bright galaxy population. That range of redshift, where only a small amount of data with the required resolution and quality is available, is particularly important for the understanding of the formation and evolution of clusters of galaxies. We have inspected the color-magnitude relation (CMR) for those clusters and measured the blue fraction of galaxies in their cores to check for evidence of evolution as found in other works. Moreover, the visual classification of the galaxy morphology has been performed and the morphology-radius relation has been examined We have not found signs of evolution neither in the slope of the CMR nor in the blue fraction of galaxies. A diversity of situations regarding those parameters and in the morphological mixing has been noticed, with two out of five clusters containing a dominant late-type core population. The cluster A1878 stands out as some of its properties differ from those of the other clusters in the sample. No clear signs of evolution appear in our analysis. The data support the view that the morphology and the stellar content of the galaxies in our clusters have been already settled at z $\sim$ 0.2. Only the fraction of interacting galaxies in the clusters appear to be larger than in clusters like Coma although the number of clusters in the sample is small to give a definitive conclusion.Comment: 16 pages, 8 figures, 4 tables, 1 longtable The paper has been already accepted but still not publishe

Developmental trajectories of cortical thickness by functional brain network: The roles of pubertal timing and socioeconomic status

The human cerebral cortex undergoes considerable changes during development, with cortical maturation patterns reflecting regional heterogeneity that generally progresses in a posterior-to-anterior fashion. However, the organizing principles that govern cortical development remain unclear. In the current study, we characterized age-related differences in cortical thickness (CT) as a function of sex, pubertal timing, and two dissociable indices of socioeconomic status (i.e., income-to-needs and maternal education) in the context of functional brain network organization, using a cross-sectional sample (n = 789) diverse in race, ethnicity, and socioeconomic status from the Lifespan Human Connectome Project in Development (HCP-D). We found that CT generally followed a linear decline from 5 to 21 years of age, except for three functional networks that displayed nonlinear trajectories. We found no main effect of sex or age by sex interaction for any network. Earlier pubertal timing was associated with reduced mean CT and CT in seven networks. We also found a significant age by maternal education interaction for mean CT across cortex and CT in the dorsal attention network, where higher levels of maternal education were associated with steeper age-related decreases in CT. Taken together, our results suggest that these biological and environmental variations may impact the emerging functional connectome

Empirical transmit field bias correction of T1w/T2w myelin maps

T1-weighted divided by T2-weighted (T1w/T2w) myelin maps were initially developed for neuroanatomical analyses such as identifying cortical areas, but they are increasingly used in statistical comparisons across individuals and groups with other variables of interest. Existing T1w/T2w myelin maps contain radiofrequency transmit field (B1+) biases, which may be correlated with these variables of interest, leading to potentially spurious results. Here we propose two empirical methods for correcting these transmit field biases using either explicit measures of the transmit field or alternatively a \u27pseudo-transmit\u27 approach that is highly correlated with the transmit field at 3T. We find that the resulting corrected T1w/T2w myelin maps are both better neuroanatomical measures (e.g., for use in cross-species comparisons), and more appropriate for statistical comparisons of relative T1w/T2w differences across individuals and groups (e.g., sex, age, or body-mass-index) within a consistently acquired study at 3T. We recommend that investigators who use the T1w/T2w approach for mapping cortical myelin use these B1+ transmit field corrected myelin maps going forward

Higher pre-infection vitamin E levels are associated with higher mortality in HIV-1-infected Kenyan women: a prospective study

Background: Low vitamin E levels are often found in HIV-1 infection, and studies have suggested that higher levels may decrease the risk of disease progression. However, vitamin E supplementation has also been reported to increase CCR5 expression, which could increase HIV- 1 replication. We hypothesized that vitamin E levels at HIV-1 acquisition may influence disease progression. Methods: Vitamin E status was measured in stored samples from the last pre-infection visit for 67 Kenyan women with reliably estimated dates of HIV-1 acquisition. Regression analyses were used to estimate associations between pre-infection vitamin E and plasma viral load, time to CD4 count less than 200 cells/[micro]L, and mortality. Results: After controlling for potential confounding factors, each 1 mg/L increase in pre-infection vitamin E was associated with 0.08 log[sub]10 copies/mL (95% CI -0.01 to +0.17) higher set point viral load and 1.58-fold higher risk of mortality (95% CI 1.15�2.16). The association between higher preinfection vitamin E and mortality persisted after adjustment for set point viral load (HR 1.55, 95% CI 1.13�2.13). Conclusion: Higher pre-infection vitamin E levels were associated with increased mortality. Further research is needed to elucidate the role vitamin E plays in HIV-1 pathogenesis.This research was supported by National Institutes of Health grants AI-43844 and AI-38518 (all authors), and Fogarty International Center grant D43 TW000007 (SMG)

Consumer perceptions of co-branding alliances: Organizational dissimilarity signals and brand fit

This study explores how consumers evaluate co-branding alliances between dissimilar partner firms. Customers are well aware that different firms are behind a co-branded product and observe the partner firms’ characteristics. Drawing on signaling theory, we assert that consumers use organizational characteristics as signals in their assessment of brand fit and for their purchasing decisions. Some organizational signals are beyond the control of the co-branding partners or at least they cannot alter them on short notice. We use a quasi-experimental design and test how co-branding partner dissimilarity affects brand fit perception. The results show that co-branding partner dissimilarity in terms of firm size, industry scope, and country-of-origin image negatively affects brand fit perception. Firm age dissimilarity does not exert significant influence. Because brand fit generally fosters a benevolent consumer attitude towards a co-branding alliance, the findings suggest that high partner dissimilarity may reduce overall co-branding alliance performance