Red Galaxy Growth and the Halo Occupation Distribution

We have traced the past 7 Gyr of red galaxy stellar mass growth within dark matter halos. We have determined the halo occupation distribution, which describes how galaxies reside within dark matter halos, using the observed luminosity function and clustering of 40,696 0.2<z<1.0 red galaxies in Bootes. Half of 10^{11.9} Msun/h halos host a red central galaxy, and this fraction increases with increasing halo mass. We do not observe any evolution of the relationship between red galaxy stellar mass and host halo mass, although we expect both galaxy stellar masses and halo masses to evolve over cosmic time. We find that the stellar mass contained within the red population has doubled since z=1, with the stellar mass within red satellite galaxies tripling over this redshift range. In cluster mass halos most of the stellar mass resides within satellite galaxies and the intra-cluster light, with a minority of the stellar mass residing within central galaxies. The stellar masses of the most luminous red central galaxies are proportional to halo mass to the power of a third. We thus conclude that halo mergers do not always lead to rapid growth of central galaxies. While very massive halos often double in mass over the past 7 Gyr, the stellar masses of their central galaxies typically grow by only 30%.Comment: Accepted for publication in the ApJ. 34 pages, 22 Figures, 5 Table

A novel compartment, the 'subqpical stem' of the aerial hyphae, is the location of a sigN-dependent, developmentally distinct transcription in Streptomyces coelicolor.

Streptomyces coelicolor has nine SigB-like RNA polymerase sigma factors, several of them implicated in morphological differentiation and/or responses to different stresses. One of the nine, SigN, is the focus of this article. A constructed sigN null mutant was delayed in development and exhibited a bald phenotype when grown on minimal medium containing glucose as carbon source. One of two distinct sigN promoters, sigNP1, was active only during growth on solid medium, when its activation coincided with aerial hyphae formation. Transcription from sigNP1 was readily detected in several whi mutants (interrupted in morphogenesis of aerial mycelium into spores), but was absent from all bld mutants tested, suggesting that sigNP1 activity was restricted to the aerial hyphae. It also depended on sigN, thus sigN was autoregulated. Mutational and transcription studies revealed no functional significance to the location of sigN next to sigF, encoding another SigB-like sigma factor. We identified another potential SigN target, nepA, encoding a putative small secreted protein. Transcription of nepA originated from a single, aerial hyphae-specific and sigN-dependent promoter. While in vitro run-off transcription using purified SigN on the Bacillus subtilis ctc promoter confirmed that SigN is an RNA polymerase sigma factor, SigN failed to initiate transcription from sigNP1 and from the nepA promoter in vitro. Additional in vivo data indicated that further nepA upstream sequences, which are likely to bind a potential activator, are required for successful transcription. Using a nepA–egfp transcriptional fusion we located nepA transcription to a novel compartment, the ‘subapical stem’ of the aerial hyphae. We suggest that this newly recognized compartment defines an interface between the aerial and vegetative parts of the Streptomyces colony and might also be involved in communication between these two compartments

A Prospective Study of Periodontal Disease and Risk of Gastric and Duodenal Ulcer in Male Health Professionals

OBJECTIVES: Periodontal disease has been associated with higher circulating levels of inflammatory markers and conditions associated with chronic inflammation, including vascular disease, diabetes mellitus, and cancer. Limited data exist on the relationship between periodontal disease and gastric and duodenal ulcer. METHODS: We conducted a prospective cohort study of 49,120 men in the Health Professionals Follow-up Study, aged 40–75 years at enrollment in 1986. Biennially, we assessed periodontal disease, tooth loss, and other risk factors for gastric and duodenal ulcer. We validated diagnoses of gastric and duodenal ulcer through medical record review. We used Cox proportional hazards modeling, adjusting for potential confounders, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: We documented 138 cases of gastric ulcer and 124 cases of duodenal ulcer with available information on Helicobacter pylori status over 24 years of follow-up. After adjustment for risk factors, including smoking and regular use of aspirin and non-steroidal anti-inflammatory drugs, men with periodontal disease with bone loss had a multivariate HR of ulcer of 1.62 (95% CI, 1.24–2.12). Periodontal disease appeared to be associated with a similar risk of developing ulcers that were H. pylori negative (HR 1.75; 95% CI, 1.26–2.43) than H. pylori positive (HR 1.40; 95% CI, 0.87-2.24), as well as ulcers in the stomach (HR 1.75; 95% CI, 1.21–2.53) than ulcers in the duodenum (HR 1.47; 95% CI, 0.98–2.19). CONCLUSIONS: Periodontal disease is associated with an increased risk of incident gastric and duodenal ulcer. This relationship may be mediated by alterations in the oral and gastrointestinal microbiome and/or systemic inflammatory factors

Theorising variation in engagement in professional and curriculum development: performativity, capital, systems and purpose

Increasingly, policymakers seek to improve the quality of teaching through curriculum innovations and continuing professional development (CPD) programmes. However, engagement by schools and teachers varies due to mediating influences of neoliberal policies. In this article, we contribute to understanding how these tendencies affect participation. Problematising the notion of context, we examine ways in which systemic influences interacted with participation in a government-funded mathematics professional and curriculum development programme and also with participants’ purposes. A 3-level clustered Randomised Controlled Trial (RCT) and an implementation and process evaluation were augmented by in-depth case studies, cross-case analysis and the application of theoretical constructs to interpret findings. Theories of capital, figured worlds and systemic coupling are utilised to theorise context. Different levels of engagement are partly explainable by: the interaction of schools' relative systemic advantage and disadvantage; their orientation and coupling to performativity regimes; and the alignment or dissonance between continuing professional development or change programmes and the pedagogical and CPD cultures and purposes of the ‘actors’ (schools, departments and teachers). Performativity concerns restricted what were considered legitimate outcomes in some case study schools. This depended on teachers and schools' positioning in terms of relative degrees of systemic privilege or disadvantage - understood as economic, cultural, social and symbolic capital - and also in terms of figured worlds and system coupling. The case studies provide insights into how collaborative professional learning can be fostered more productively. Methodologically, we demonstrate the power of combining methodologies and applying explanatory social theory to augment quasi-experimental paradigms

The Effect of Mass Ratio on the Morphology and Time-scales of Disc Galaxy Mergers

The majority of galaxy mergers are expected to be minor mergers. The observational signatures of minor mergers are not well understood, thus there exist few constraints on the minor merger rate. This paper seeks to address this gap in our understanding by determining if and when minor mergers exhibit disturbed morphologies and how they differ from the morphology of major mergers. We simulate a series of unequal-mass moderate gas-fraction disc galaxy mergers. With the resulting g-band images, we determine how the time-scale for identifying galaxy mergers via projected separation and quantitative morphology (the Gini coefficient G, asymmetry A, and the second-order moment of the brightest 20% of the light M20) depends on the merger mass ratio, relative orientations and orbital parameters. We find that G-M20 is as sensitive to 9:1 baryonic mass ratio mergers as 1:1 mergers, with observability time-scales ~ 0.2-0.4 Gyr. In contrast, asymmetry finds mergers with baryonic mass ratios between 4:1 and 1:1 (assuming local disc galaxy gas-fractions). Asymmetry time-scales for moderate gas-fraction major disc mergers are ~ 0.2-0.4 Gyr, and less than 0.06 Gyr for moderate gas-fraction minor mergers. The relative orientations and orbits have little effect on the time-scales for morphological disturbances. Observational studies of close pairs often select major mergers by choosing paired galaxies with similar luminosities and/or stellar masses. Therefore, the various ways of finding galaxy mergers (G-M20, A, close pairs) are sensitive to galaxy mergers of different mass ratios. By comparing the frequency of mergers selected by different techniques, one may place empirical constraints on the major and minor galaxy merger rates.Comment: 16 pages; resubmitted to MNRA

'They wouldn't know how it feels . . .': characteristics of quality care from young people's perspectives: a participatory research project

Literature suggests there is a need to hear from children themselves about the quality of healthcare they receive and, although their views are increasingly sought, little is known about children’s definitions of ‘high or low quality care’. This article reports on a participatory, qualitative study that set out to explore with children and young people whether they could be involved in monitoring the quality of hospital care. Nine young people played an active role in the research process, collecting data from an additional 129 participants aged between 9 and 14. Five characteristics of quality care were identified: ‘technical expertise’, ‘friendly staff ’, ‘respect’, ‘choice’ and ‘explanations’

Cultural relativism and the discourse of intercultural communication: aporias of praxis in the intercultural public sphere

The premise of much intercultural communication pedagogy and research is to educate people from different cultures towards open and transformative positions of mutual understanding and respect. This discourse in the instance of its articulation realises and sustains Intercultural Communication epistemologically – as an academic field of social enquiry, and judgementally – as one which locates itself on a moral terrain. By adopting an ethical stance towards difference, the discourse of intercultural communication finds itself caught in a series of aporias, or performative contradictions, where interculturalists are projected simultaneously into positions of cultural relativism on the one hand and ideological totalism on the other. Such aporias arise because the theoretical premises upon which the discourse relies are problematic. We trace these thematics to a politics of presence operating within the discourse of intercultural communication and links this to questions of judgement and truth in the intercultural public sphere. We propose that the politics of presence be set aside in favour of an intercultural praxis which is oriented to responsibility rather than to truth

The SCottish Alcoholic Liver disease Evaluation: a population-level matched cohort study of hospital-based costs, 1991-2011

Studies assessing the costs of alcoholic liver disease are lacking. We aimed to calculate the costs of hospitalisations before and after diagnosis compared to population controls matched by age, sex and socio-economic deprivation. We aimed to use population level data to identify a cohort of individuals hospitalised for the first time with alcoholic liver disease in Scotland between 1991 and 2011.Incident cases were classified by disease severity, sex, age group, socio-economic deprivation and year of index admission. 5 matched controls for every incident case were identified from the Scottish population level primary care database. Hospital costs were calculated for both cases and controls using length of stay from morbidity records and hospital-specific daily rates by specialty. Remaining lifetime costs were estimated using parametric survival models and predicted annual costs. 35,208 incident alcoholic liver disease hospitalisations were identified. Mean annual hospital costs for cases were 2.3 times that of controls pre diagnosis (£804 higher) and 10.2 times (£12,774 higher) post diagnosis. Mean incident admission cost was £6,663. Remaining lifetime cost for a male, 50-59 years old, living in the most deprived area diagnosed with acoholic liver disease was estimated to be £65,999 higher than the matched controls (£12,474 for 7.43 years remaining life compared to £1,224 for 21.8 years). In Scotland, alcoholic liver disease diagnosis is associated with significant increases in admissions to hospital both before and after diagnosis. Our results provide robust population level estimates of costs of alcoholic liver disease for the purposes of health-care delivery, planning and future cost-effectiveness analyses

The Effect of Gas Fraction on the Morphology and Time-scales of Disc Galaxy Mergers

Gas-rich galaxy mergers are more easily identified by their disturbed morphologies than mergers with less gas. Because the typical gas fraction of galaxy mergers is expected to increase with redshift, the under-counting of low gas-fraction mergers may bias morphological estimates of the evolution of galaxy merger rate. To understand the magnitude of this bias, we explore the effect of gas fraction on the morphologies of a series of simulated disc galaxy mergers. With the resulting g-band images, we determine how the time-scale for identifying major and minor galaxy mergers via close projected pairs and quantitative morphology (the Gini coefficient G, the second-order moment of the brightest 20% of the light M20, and asymmetry A) depends on baryonic gas fraction f(gas). Strong asymmetries last significantly longer in high gas-fraction mergers of all mass ratios, with time-scales ranging from >= 300 Myr for f(gas) ~ 20% to >= 1 Gyr for f(gas) ~ 50%. Therefore the strong evolution with redshift observed in the fraction of asymmetric galaxies may reflect evolution in the gas properties of galaxies rather than the global galaxy merger rate. On the other hand, the time-scale for identifying a galaxy merger via G-M20 is weakly dependent on gas-fraction (~ 200-400 Myr), consistent with the weak evolution observed for G-M20 mergers.Comment: 15 pages; resubmitted to MNRA

Robust Optical Richness Estimation with Reduced Scatter

Reducing the scatter between cluster mass and optical richness is a key goal for cluster cosmology from photometric catalogs. We consider various modifications to the red-sequence matched filter richness estimator of Rozo et al. (2009), and evaluate their impact on the scatter in X-ray luminosity at fixed richness. Most significantly, we find that deeper luminosity cuts can reduce the recovered scatter, finding that sigma_lnLX|lambda=0.63+/-0.02 for clusters with M_500c >~ 1.6e14 h_70^-1 M_sun. The corresponding scatter in mass at fixed richness is sigma_lnM|lambda ~ 0.2-0.3 depending on the richness, comparable to that for total X-ray luminosity. We find that including blue galaxies in the richness estimate increases the scatter, as does weighting galaxies by their optical luminosity. We further demonstrate that our richness estimator is very robust. Specifically, the filter employed when estimating richness can be calibrated directly from the data, without requiring a-priori calibrations of the red-sequence. We also demonstrate that the recovered richness is robust to up to 50% uncertainties in the galaxy background, as well as to the choice of photometric filter employed, so long as the filters span the 4000 A break of red-sequence galaxies. Consequently, our richness estimator can be used to compare richness estimates of different clusters, even if they do not share the same photometric data. Appendix 1 includes "easy-bake" instructions for implementing our optimal richness estimator, and we are releasing an implementation of the code that works with SDSS data, as well as an augmented maxBCG catalog with the lambda richness measured for each cluster.Comment: Submitted to ApJ. 20 pages in emulateapj forma