Reanalysis of the spectrum of the z=10 galaxy

In a recent paper Pello et al. reported observations of a faint galaxy, gravitationally lensed by the galaxy cluster Abell 1835. Deep J-band spectroscopy revealed a weak emission line near 1.34 microns, detected in two spectra with different central wavelengths. The line was interpreted as Lyman-alpha at redshift z=10.0. This interpretation is supported by the broad-band photometric spectral energy distribution, and by the location of the galaxy close to the lens critical line for this redshift. We have reanalysed the two spectra, just released from the data archive. Our analysis includes allowance for wavelength shifts due to transverse drift of the object in the slit. We do not detect a significant emission line at the reported location, or nearby, at either grating setting, nor in the combined spectrum. We provide a possible explanation for the reported detection as due to spurious positive flux introduced in the sky-subtraction stage as a result of variable hot pixels. We provide our final reduced 2D frame, and corresponding error array.Comment: 4 pages, 1 figure. To appear in A&A Letters. Added possible explanation for reported emission line as due to variable hot pixel

Dynamical virial masses of Lyman-break galaxy haloes at z=3

We improve on our earlier dynamical estimate of the virial masses of the haloes of Lyman-break galaxies (LBGs) at redshift z=3 by accounting for the effects of seeing, slit width, and observational uncertainties. From an analysis of the small number of available rotation curves for LBGs we determine a relation Vc7=(1.9+/-0.2)sigma between circular velocity at a radius of 7kpc, and central line velocity width. We use this relation to transform the measured velocity widths of 32 LBGs to the distribution of circular velocities, for the population of LBGs brighter than R=25.5. We compare this distribution against the predicted distribution for the 'massive-halo' model in which LBGs pinpoint all of the highest mass dark matter haloes at that epoch. The observed LBG circular velocities are smaller than the predicted circular velocities by a factor >1.4+/-0.15. This is a lower limit as we have ignored any increase of circular velocity caused by baryonic dissipation. The massive-halo model predicts a median halo virial mass of 10^12.3 Msol, and a small spread of circular velocities. Our median estimated dynamical mass is <10^(11.6+/-0.3) Msol, which is significantly smaller; furthermore, the spread of our circular velocities is much larger than the massive-halo prediction. These results are consistent with a picture which leaves some of the most-massive haloes available for occupation by other populations which do not meet the LBG selection criteria. The median halo mass recently estimated by Adelberger et al. from the measured clustering of LBGs is 10^(11.86+/-0.3) Msol. Our dynamical analysis appears to favour lower masses and to be more in line with the median mass predicted by the collisional starburst model of Somerville et al., of 10^11.3 Msol. [abridged]Comment: 6 pages, 5 figures, MNRAS Letters, Accepte

Abnormal liver function tests in acute heart failure: relationship with clinical characteristics and outcome in the PROTECT study

Aims: Episodes of acute heart failure (AHF) unfavourably affect multiple organs, which may have an adverse impact on the outcomes. We investigated the prevalence and clinical consequences of abnormal liver function tests (LFTs) in AHF patients enrolled in the PROTECT study. Methods and results: The LFTs comprised serial assessment of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and albumin at baseline and during follow-up (daily until discharge, on days 7 and 14). The prevalence of abnormal LFTs (above upper limit of normal for AST and ALT or below lower limit of normal for albumin) was: at baseline AST 20%, ALT 12%, albumin 40%; and at day 14: AST 15%, ALT 9%, albumin 26%. Abnormal LFTs at baseline were associated with a higher risk of in-hospital death with odds ratios [95% confidence interval (CI)] of 3.5 (1.7–7.3) for AST, 3.9 (1.8–8.4) for ALT, and 2.8 (1.3–5.9) for albumin (all P &lt; 0.01). Abnormal baseline and discharge LFTs had an unfavourable impact on 180-day mortality with hazard ratios (95% CI) for baseline AST, ALT, and albumin of 1.3 (1.0–1.7), 1.1 (1.0–1.2), 1.4 (1.1–1.8), respectively, and 1.5 (1.1–2.0), 1.5 (1.0–2.2), and 1.6 (1.2–2.1), for discharge AST, ALT, albumin, respectively (all P &lt; 0.05). Analysis of LFTs trajectories (calculated as changes in LFTs over time) revealed that increasing AST and ALT on day 3 as well as decreasing albumin on day 4 were independent prognosticators of 180-day outcome (all P &lt; 0.05). Conclusions: Abnormal LFTs are frequent in AHF at baseline and during hospital stay and predict worse outcomes. Whether this association is causal and what are the underlying mechanisms involved require further study

Software infrastructure for solving non-linear partial differential equations and its application to modelling crustal fault systems

In this paper we will give a brief introduction into the Python-based modelling language escript. We will present a model for the dynamics of fault systems in the Earth's crust and then show how escript is used to implement solution algorithms for a dynamic as well as a quasi-static scenario

Multicycle dynamics of fault systems and static and dynamic triggering of earthquakes

Dynamic simulations of rupture propagation and multiple earthquake cycles for varying fault geometries are presented. We investigate the role of both dynamic and static stress changes on earthquake triggering. Dynamic stress triggering of earthquakes is caused by the passage of seismic waves, whereas static stress triggering is due to net slippage on a fault resulting from an earthquake. Static stress changes represented by a Coulomb failure function and its relationship to seismicity rate change is a relatively well-known mechanism, whereas the physical origin of dynamic triggering remains one of the least understood aspects of earthquake nucleation. We investigate these mechanisms by analysing seismicity patterns with varying fault separation, geometry and with and without dynamic triggering present