Unveiling the nature of bright z ~ 7 galaxies with the Hubble Space Telescope

We present new Hubble Space Telescope/Wide Field Camera 3 imaging of 25 extremely luminous (-23.2 < M_ UV < -21.2) Lyman-break galaxies (LBGs) at z ~ 7. The sample was initially selected from 1.65 deg^2 of ground-based imaging in the UltraVISTA/COSMOS and UDS/SXDS fields, and includes the extreme Lyman-alpha emitters, `Himiko' and `CR7'. A deconfusion analysis of the deep Spitzer photometry available suggests that these galaxies exhibit strong rest-frame optical nebular emission lines (EW_0(H_beta + [OIII]) > 600A). We find that irregular, multiple-component morphologies suggestive of clumpy or merging systems are common (f_multi > 0.4) in bright z ~ 7 galaxies, and ubiquitous at the very bright end (M_UV < -22.5). The galaxies have half-light radii in the range r_1/2 ~ 0.5-3 kpc. The size measurements provide the first determination of the size-luminosity relation at z ~ 7 that extends to M_UV ~ -23. We find the relation to be steep with r_1/2 ~ L^1/2. Excluding clumpy, multi-component galaxies however, we find a shallower relation that implies an increased star-formation rate surface density in bright LBGs. Using the new, independent, HST/WFC3 data we confirm that the rest-frame UV luminosity function at z ~ 7 favours a power-law decline at the bright-end, compared to an exponential Schechter function drop-off. Finally, these results have important implications for the Euclid mission, which we predict will detect > 1000 similarly bright galaxies at z ~ 7. Our new HST imaging suggests that the vast majority of these galaxies will be spatially resolved by Euclid, mitigating concerns over dwarf star contamination.Comment: 26 pages, 11 figures and 5 tables. Updated to match MNRAS accepted versio

Accelerating Positive Change In Electronic Recrds Management - An Emprical Toolkit Of Solutions

The AC+erm project aims to investigate and critically explore issues and practical strategies for accelerating positive change in electronic records management. The project’s focus is on designing an organisational-centred architecture from three perspectives: people, process and technology. This paper introduces the project, describes the methodology (a systematic literature review, e-Delphi studies and colloquia) and presents solutions for improving ERM developed from the people and process e-Delphi responses. ERM is particularly challenging and the solutions offered by the Delphi participants are numerous, and range in scale and complexity. The only firm conclusion that one can draw is that the majority of the solutions are people-focussed ones. The Cynefin framework is introduced as one approach for providing a conceptual overview to our findings on ERM. The sample solutions presented in this paper provide a toolkit of ‘probes’ and ‘interventions’ for practical application in organisations

Carboplatin/taxane-induced gastrointestinal toxicity: a pharmacogenomics study on the SCOTROC1 trial

Carboplatin/taxane combination is first-line therapy for ovarian cancer. However, patients can encounter treatment delays, impaired quality of life, even death because of chemotherapy-induced gastrointestinal (GI) toxicity. A candidate gene study was conducted to assess potential association of genetic variants with GI toxicity in 808 patients who received carboplatin/taxane in the Scottish Randomized Trial in Ovarian Cancer 1 (SCOTROC1). Patients were randomized into discovery and validation cohorts consisting of 404 patients each. Clinical covariates and genetic variants associated with grade III/IV GI toxicity in discovery cohort were evaluated in replication cohort. Chemotherapy-induced GI toxicity was significantly associated with seven single-nucleotide polymorphisms in the ATP7B, GSR, VEGFA and SCN10A genes. Patients with risk genotypes were at 1.53 to 18.01 higher odds to develop carboplatin/taxane-induced GI toxicity (P&#60;0.01). Variants in the VEGF gene were marginally associated with survival time. Our data provide potential targets for modulation/inhibition of GI toxicity in ovarian cancer patients

Migration and multiple sclerosis in immigrants to Australia from United Kingdom and Ireland: a reassessment. I. Risk of MS by age at immigration

A previous study of the prevalence of multiple sclerosis (MS) in 1981 among immigrants from the United Kingdom and Ireland to Australia found that the prevalence for those with age at immigration (AAI) under 15 years of age did not differ from the older immigrants. We have reanalysed the original materials as well as census data for 1901–1981 for UKI and other high MS risk country immigrants. There was a highly significant trend in the prevalence rates of all Australians from New South Wales (NSW) to South Australia (SA) to Western Australia (WA) to Queensland (QLD). Rates by state among the Australian-born were almost identical to these, but there was no prevalence gradient for the UKI-born. The denominator population at risk of MS by AAI was calculated from special census tables of length of residence in Australia by age 0–79 in 1981 for UKI immigrants 1947–1981. The numerator was limited to the subset of 258 MS (Group II) also immigrating in 1947 and later, and age 0–79 in 1981. The absolute risk of MS for these migrants to the four states entering at age 0–14 was 22/100,000, significantly less than for all older age groups; age 15–39 immigrants had a risk of 54/100,000. Similar risk ratios for 0–14 versus 15–39 by state were 31 versus 61 (NSW), 29 versus 44 (QLD), 11 versus 50 (SA), 15 versus 51 (WA)

Structure of solutions of the Skyrme model on three-sphere. Numerical results

The hedgehog Skyrme model on three-sphere admits very rich spectrum of solitonic solutions which can be encompassed by a strikingly simple scheme. The main result of this paper is the statement of the tripartite structure of solutions of the model and the discovery in what configurations these solutions appear. The model contains features of more complicated models in General Relativity and as such can give insight into them.Comment: 20 pages, 13 figures in, with emai

Toxoplasma effectors targeting host signaling and transcription

Early electron microscopy studies revealed the elaborate cellular features that define the unique adaptations of apicomplexan parasites. Among these were bulbous rhoptry (ROP) organelles and small, dense granules (GRAs), both of which are secreted during invasion of host cells. These early morphological studies were followed by the exploration of the cellular contents of these secretory organelles, revealing them to be comprised of highly divergent protein families with few conserved domains or predicted functions. In parallel, studies on host-pathogen interactions identified many host signaling pathways that were mysteriously altered by infection. It was only with the advent of forward and reverse genetic strategies that the connections between individual parasite effectors and the specific host pathways that they targeted finally became clear. The current repertoire of parasite effectors includes ROP kinases and pseudokinases that are secreted during invasion and that block host immune pathways. Similarly, many secretory GRA proteins alter host gene expression by activating host transcription factors, through modification of chromatin, or by inducing small noncoding RNAs. These effectors highlight novel mechanisms by whichhas learned to harness host signaling to favor intracellular survival and will guide future studies designed to uncover the additional complexity of this intricate host-pathogen interaction

PKS 1830-211: A Face-On Spiral Galaxy Lens

We present new Hubble Space Telescope images of the gravitational lens PKS 1830-211, which allow us to characterize the lens galaxy and update the determination of the Hubble constant from this system. The I-band image shows that the lens galaxy is a face-on spiral galaxy with clearly delineated spiral arms. The southwestern image of the background quasar passes through one of the spiral arms, explaining the previous detections of large quantities of molecular gas and dust in front of this image. The lens galaxy photometry is consistent with the Tully-Fisher relation, suggesting the lens galaxy is a typical spiral galaxy for its redshift. The lens galaxy position, which was the main source of uncertainty in previous attempts to determine H_0, is now known precisely. Given the current time delay measurement and assuming the lens galaxy has an isothermal mass distribution, we compute H_0 = 44 +/- 9 km/s/Mpc for an Omega_m = 0.3 flat cosmological model. We describe some possible systematic errors and how to reduce them. We also discuss the possibility raised by Courbin et al. (2002), that what we have identified as a single lens galaxy is actually a foreground star and two separate galaxies.Comment: 21 pp., 4 figs., accepted by ApJ, section added to discuss related work by Courbin et al. (astro-ph/0202026

NMA Survey of CO and HCN Emission from Nearby Active Galaxies

High resolution (a few arcseconds) observations of CO(1-0) and HCN(1-0) emission from nearby Seyfert galaxies have been conducted with the Nobeyama Millimeter Array. Based on the observed CO distributions and kinematics,we suggest that a small scale (a few 100 pc - a few kpc) distortion of the underlying potential seems to be necessary for Seyfert activity, although it is not a sufficient condition. We also find that the Toomre's Q values in the centers of Seyfert galaxies tend to be larger than unity, indicating the circumnuclear molecular gas disks around Seyfert nuclei would be gravitationally stable. The HCN/CO integrated intensity ratios (R_HCN/CO) range over an order of magnitude, from 0.086 to 0.6. The Seyfert galaxies with high R_HCN/CO may have an extended (r ~ 100 pc scale) envelope of obscuring material. The presence of kpc scale jet/ outflow might be also related to the extremely high R_HCN/CO.Comment: To appear in the Proceedings of the 3rd Cologne-Zermatt Symposium, ``The Physics and Chemistry of the Interstellar Medium'