The host galaxies of luminous radio-quiet quasars

We present the results of a deep K-band imaging study which reveals the host galaxies around a sample of luminous radio-quiet quasars. The K-band images, obtained at UKIRT, are of sufficient quality to allow accurate modelling of the underlying host galaxy. Initially, the basic structure of the hosts is revealed using a modified Clean deconvolution routine optimised for this analysis. 2 of the 14 quasars are shown to have host galaxies with violently disturbed morphologies which cannot be modelled by smooth elliptical profiles. For the remainder of our sample, 2D models of the host and nuclear component are fitted to the images using the chi-squared statistic to determine goodness of fit. Host galaxies are detected around all of the quasars. The reliability of the modelling is extensively tested, and we find the host luminosity to be well constrained for 9 quasars. The derived average K-band absolute K-corrected host galaxy magnitude for these luminous radio-quiet quasars is =-25.15+/-0.04, slightly more luminous than an L* galaxy. The spread of derived host galaxy luminosities is small, although the spread of nuclear-to-host ratios is not. These host luminosities are shown to be comparable to those derived from samples of quasars of lower total luminosity and we conclude that there is no correlation between host and nuclear luminosity for these quasars. Nuclear-to-host ratios break the lower limit previously suggested from studies of lower nuclear luminosity quasars and Seyfert galaxies. Morphologies are less certain but, on the scales probed by these images, some hosts appear to be dominated by spheroids but others appear to have disk-dominated profiles.Comment: 16 pages, 8 figures, revised version to be published in MNRA

Arthroscopic anterior talofibular ligament repair for lateral instability of the ankle

UNLABELLED: Although several arthroscopic procedures for lateral ligament instability of the ankle have been reported recently, it is difficult to augment the reconstruction by arthroscopically tightening the inferior extensor retinaculum. There is also concern that when using the inferior extensor retinaculum, this is not strictly an anatomical repair since its calcaneal attachment is different to that of the calcaneofibular ligament. If a ligament repair is completed firmly, it is unnecessary to add argumentation with inferior extensor retinaculum. The authors describe a simplified technique, repair of the lateral ligament alone using a lasso-loop stitch, which avoids additionally tighten the inferior extensor retinaculum. In this paper, it is described an arthroscopic anterior talofibular ligament repair using lasso-loop stitch alone for lateral instability of the ankle that is likely safe for patients and minimal invasive. LEVEL OF EVIDENCE: Therapeutic study, Level V

A physical activity intervention for children with type 1 diabetes- steps to active kids with diabetes (STAK-D): a feasibility study

Background This study describes the development and feasibility evaluation of a physical activity intervention for children with type 1 diabetes called ‘Steps to Active Kids with Diabetes’ (STAK-D). It aims to explore the feasibility and acceptability of the intervention and study design. Methods Thirteen children aged 9-11 years and their parents were recruited from one paediatric diabetes clinic. A process evaluation was conducted alongside a two-arm randomised feasibility trial, including assessment of rate of recruitment, adherence, retention, data completion and burden, implementation fidelity and adverse events. Qualitative interviews with children (n=9), parents (n=8), healthcare professionals (n=3) and STAK-D volunteers (n=8) explored intervention acceptability. Interviews were analysed thematically. Results Rate of recruitment was 25%, with 77% retention at 3-month follow-up. Study burden was low, data completion was high and the intervention was delivered as per protocol. No serious adverse event was reported. Engagement with intervention materials was generally good, but attendance at group activity sessions was low due to logistical barriers. Interview analysis identified preferred methods of recruitment, motivations for recruitment, barriers and facilitators to adherence, the experience of data collection, experience of the STAK-D programme and its perceived benefits. Conclusions STAK-D was feasible and acceptable to children, their parents and healthcare professionals, but group sessions may present logistical issues. Recruitment and retention may be improved with a clinic-wide approach to recruitment. Trial registration This trial was registered on ClinicalTrials.gov: NCT02144337 (16/01/2014). Keywords Children, feasibility study, intervention, paediatric diabetes, physical activity, process evaluation, self-efficacy, type 1 diabete

A massive, quiescent galaxy at redshift of z=3.717

In the early Universe finding massive galaxies that have stopped forming stars present an observational challenge as their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys. These have revealed the presence of massive, quiescent early-type galaxies appearing in the universe as early as z$\sim$2, an epoch 3 Gyr after the Big Bang. Their age and formation processes have now been explained by an improved generation of galaxy formation models where they form rapidly at z$\sim$3-4, consistent with the typical masses and ages derived from their observations. Deeper surveys have now reported evidence for populations of massive, quiescent galaxies at even higher redshifts and earlier times, however the evidence for their existence, and redshift, has relied entirely on coarsely sampled photometry. These early massive, quiescent galaxies are not predicted by the latest generation of theoretical models. Here, we report the spectroscopic confirmation of one of these galaxies at redshift z=3.717 with a stellar mass of 1.7$\times$10$^{11}$ M$_\odot$ whose absorption line spectrum shows no current star-formation and which has a derived age of nearly half the age of the Universe at this redshift. The observations demonstrates that the galaxy must have quickly formed the majority of its stars within the first billion years of cosmic history in an extreme and short starburst. This ancestral event is similar to those starting to be found by sub-mm wavelength surveys pointing to a possible connection between these two populations. Early formation of such massive systems is likely to require significant revisions to our picture of early galaxy assembly.Comment: 6 pages, 7 figures. This is the final preprint corresponding closely to the published version. Uploaded 6 months after publication in accordance with Nature polic

Measuring D_A and H at z=0.35 from the SDSS DR7 LRGs using baryon acoustic oscillations

We present measurements of the angular diameter distance D_A(z) and the Hubble parameter H(z) at z=0.35 using the anisotropy of the baryon acoustic oscillation (BAO) signal measured in the galaxy clustering distribution of the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) Luminous Red Galaxies (LRG) sample. Our work is the first to apply density-field reconstruction to an anisotropic analysis of the acoustic peak. Reconstruction partially removes the effects of non-linear evolution and redshift-space distortions in order to sharpen the acoustic signal. We present the theoretical framework behind the anisotropic BAO signal and give a detailed account of the fitting model we use to extract this signal from the data. Our method focuses only on the acoustic peak anisotropy, rather than the more model-dependent anisotropic information from the broadband power. We test the robustness of our analysis methods on 160 LasDamas DR7 mock catalogues and find that our models are unbiased at the ~0.2% level in measuring the BAO anisotropy. After reconstruction we measure D_A(z=0.35)=1050+/-38 Mpc and H(z=0.35)=84.4+/-7.0 km/s/Mpc assuming a sound horizon of r_s=152.76 Mpc. Note that these measurements are correlated with a correlation coefficient of 0.58. This represents a factor of 1.4 improvement in the error on D_A relative to the pre-reconstruction case; a factor of 1.2 improvement is seen for H.Comment: 30 pages, 21 figures, accepted by MNRAS, updated to version accepted by journa

Network Properties of Robust Immunity in Plants

Two modes of plant immunity against biotrophic pathogens, Effector Triggered Immunity (ETI) and Pattern-Triggered Immunity (PTI), are triggered by recognition of pathogen effectors and Microbe-Associated Molecular Patterns (MAMPs), respectively. Although the jasmonic acid (JA)/ethylene (ET) and salicylic acid (SA) signaling sectors are generally antagonistic and important for immunity against necrotrophic and biotrophic pathogens, respectively, their precise roles and interactions in ETI and PTI have not been clear. We constructed an Arabidopsis dde2/ein2/pad4/sid2-quadruple mutant. DDE2, EIN2, and SID2 are essential components of the JA, ET, and SA sectors, respectively. The pad4 mutation affects the SA sector and a poorly characterized sector. Although the ETI triggered by the bacterial effector AvrRpt2 (AvrRpt2-ETI) and the PTI triggered by the bacterial MAMP flg22 (flg22-PTI) were largely intact in plants with mutations in any one of these genes, they were mostly abolished in the quadruple mutant. For the purposes of this study, AvrRpt2-ETI and flg22-PTI were measured as relative growth of Pseudomonas syringae bacteria within leaves. Immunity to the necrotrophic fungal pathogen Alternaria brassicicola was also severely compromised in the quadruple mutant. Quantitative measurements of the immunity levels in all combinatorial mutants and wild type allowed us to estimate the effects of the wild-type genes and their interactions on the immunity by fitting a mixed general linear model. This signaling allocation analysis showed that, contrary to current ideas, each of the JA, ET, and SA signaling sectors can positively contribute to immunity against both biotrophic and necrotrophic pathogens. The analysis also revealed that while flg22-PTI and AvrRpt2-ETI use a highly overlapping signaling network, the way they use the common network is very different: synergistic relationships among the signaling sectors are evident in PTI, which may amplify the signal; compensatory relationships among the sectors dominate in ETI, explaining the robustness of ETI against genetic and pathogenic perturbations

Probing Dark Energy with Baryonic Acoustic Oscillations at High Redshifts

The phases as well as the amplitudes of baryonic acoustic oscillations can be extracted out of a galaxy power spectrum and used as a standard ruler in a cosmological test. A non-oscillating phenomenological fitting function is used to extract the oscillatory part of the galaxy power spectrum and to disentangle phase information from amplitude information. The method (FITEX) is tested with simulated data of the Hubble Volume Simulation to include redshift space effects, non-linear structure growth and biasing. A cosmological test is introduced, which compares the extracted oscillations against a theoretical model template to derive constraints on the $w$ parameter. The phenomenological fitting function is found to model the various distortions of the galaxy power spectrum to the sub-percent level. The various distortions only boost the amplitude of the oscillations. The theoretical template is accurate enough to test for small deviations in the phases of the oscillations, resulting from different $w$ values. A cosmological test, using the baryonic acoustic oscillations as a standard ruler, is able to constrain $w$ in a robust way.Comment: accepted for publication in Astron. Astrophys., 16 pages, 16 figure

Arthroscopic washout of the ankle for septic arthritis in a three-month-old boy

There is no report of athroscopic treatment for septic arthritis of the ankle in infants. We report a case of successful management of septic arthritis of the ankle in a three-month-old boy by arthroscopic washout. Arthroscopic washout may be a useful treatment for septic arthritis in young infants when performed early after onset

Modulation of ethylene- and heat-controlled hyponastic leaf movement in Arabidopsis thaliana by the plant defence hormones jasmonate and salicylate

Upward leaf movement (hyponastic growth) is adopted by several plant species including Arabidopsis thaliana, as a mechanism to escape adverse growth conditions. Among the signals that trigger hyponastic growth are, the gaseous hormone ethylene, low light intensities, and supra-optimal temperatures (heat). Recent studies indicated that the defence-related phytohormones jasmonic acid (JA) and salicylic acid (SA) synthesized by the plant upon biotic infestation repress low light-induced hyponastic growth. The hyponastic growth response induced by high temperature (heat) treatment and upon application of the gaseous hormone ethylene is highly similar to the response induced by low light. To test if these environmental signals induce hyponastic growth via parallel pathways or converge downstream, we studied here the roles of Methyl-JA (MeJA) and SA on ethylene- and heat-induced hyponastic growth. For this, we used a time-lapse camera setup. Our study includes pharmacological application of MeJA and SA and biological infestation using the JA-inducing caterpillar Pieris rapae as well as mutants lacking JA or SA signalling components. The data demonstrate that MeJA is a positive, and SA, a negative regulator of ethylene-induced hyponastic growth and that both hormones repress the response to heat. Taking previous studies into account, we conclude that SA is the first among many tested components which is repressing hyponastic growth under all tested inductive environmental stimuli. However, since MeJA is a positive regulator of ethylene-induced hyponastic growth and is inhibiting low light- and heat-induced leaf movement, we conclude that defence hormones control hyponastic growth by affecting stimulus-specific signalling pathways

The WiggleZ Dark Energy Survey: Direct constraints on blue galaxy intrinsic alignments at intermediate redshifts

Correlations between the intrinsic shapes of galaxy pairs, and between the intrinsic shapes of galaxies and the large-scale density field, may be induced by tidal fields. These correlations, which have been detected at low redshifts (z<0.35) for bright red galaxies in the Sloan Digital Sky Survey (SDSS), and for which upper limits exist for blue galaxies at z~0.1, provide a window into galaxy formation and evolution, and are also an important contaminant for current and future weak lensing surveys. Measurements of these alignments at intermediate redshifts (z~0.6) that are more relevant for cosmic shear observations are very important for understanding the origin and redshift evolution of these alignments, and for minimising their impact on weak lensing measurements. We present the first such intermediate-redshift measurement for blue galaxies, using galaxy shape measurements from SDSS and spectroscopic redshifts from the WiggleZ Dark Energy Survey. Our null detection allows us to place upper limits on the contamination of weak lensing measurements by blue galaxy intrinsic alignments that, for the first time, do not require significant model-dependent extrapolation from the z~0.1 SDSS observations. Also, combining the SDSS and WiggleZ constraints gives us a long redshift baseline with which to constrain intrinsic alignment models and contamination of the cosmic shear power spectrum. Assuming that the alignments can be explained by linear alignment with the smoothed local density field, we find that a measurement of \sigma_8 in a blue-galaxy dominated, CFHTLS-like survey would be contaminated by at most +/-0.02 (95% confidence level, SDSS and WiggleZ) or +/-0.03 (WiggleZ alone) due to intrinsic alignments. [Abridged]Comment: 18 pages, 12 figures, accepted to MNRAS; v2 has correction to one author's name, NO other changes; v3 has minor changes in explanation and calculations, no significant difference in results or conclusions; v4 has an additional footnote about model interpretation, no changes to data/calculations/result