The Optical Afterglow of GRB 011211

We present early-time optical photometry and spectroscopy of the optical afterglow of the gamma-ray burst GRB 011211. The spectrum of the optical afterglow contains several narrow metal lines which are consistent with the burst occurring at a redshift of 2.140 +/- 0.001. The optical afterglow decays as a power law with a slope of alpha = 0.83 +/- 0.04 for the first approximately two days after the burst at which time there is evidence for a break. The slope after the break is at least 1.4. There is evidence for rapid variations in the R-band light approximately 0.5 days after the burst. These variations suggest that there are density fluctuations near the gamma-ray burst on spatial scales of approximately 40--125 AU. The magnitude of the break in the light curve, the spectral slope, and the rate of decay in the optical, suggest that the burst expanded into an ambient medium that is homogeneous on large scales. We estimate that the local particle density is between approximately 0.1 and 10 cm^{-3} and that the total gamma-ray energy in the burst was 1.2--1.9 x 10^{50} erg. This energy is smaller than, but consistent with, the ``standard'' value of (5 +/- 2) x 10^{50} erg. Comparing the observed color of the optical afterglow with predictions of the standard beaming model suggests that the rest-frame V-band extinction in the host galaxy is less than approximately 0.03 mag.Comment: 17 pages, 4 figures, AASTeX 5.02, to appear in AJ Referee's report incorporated, minor changes in the tex

Enhancing deprescribing : a qualitative understanding of the complexities of pharmacist-led deprescribing in care homes

Funding statement This research is funded by the National Institute for Health Research (NIHR) Policy Research Programme (project reference NIHR202053). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. Acknowledgements Thank you to the pharmacists, GP practice and care home staff who took part in the interviews. We would also like to acknowledge the Norfolk and Waveney Clinical Commissioning Group as the study sponsor and our patient and public involvement colleagues Janet Gray and Christine Hanford who were supported by Jacqueline Romero, manager of PPIRes.Peer reviewedPublisher PD

Vibration dependent branching and photoelectron angular distributions observed across the Cooper minimum region of bromobenzene

Vibrational state-resolved photoelectron anisotropy parameters, beta, for the ~X 2B1, ~B 2B2, and ~C2B1 state ionizations of bromobenzene have been recorded at photon energies ranging from 20.5 to 94 eV, so spanning the region of the expected bromine Cooper minimum (CM). The ~X state displays no CM and its beta value is also independent of vibrational level, in accord with the Franck-Condon Approximation. The ~B and ~ C state beta values display the CM to differing degrees, but both show a vibrational dependence that extends well below the obvious CM dip. Calculations are presented that replicate these observations of Franck-Condon Approximation breakdown spanning an extended photon energy range. This is the first demonstration of such wide-ranging breakdown detected in the beta anisotropy parameter in the absence of any resonance. Measured and calculated vibrational branching ratios for these states are also presented. Although the ~B state branching ratios remain constant, in accord with Franck-Condon expectations, the ~X and (especially) the ~C state ratios display weak, quasi-linear variations across the studied range of photon energy, but with no apparent correlation with the CM position

Generalizing Murray's law : an optimization principle for fluidic networks of arbitrary shape and scale

Murray's law states that the volumetric flow rate is proportional to the cube of the radius in a cylindrical channel optimized to require the minimum work to drive and maintain the fluid. However, application of this principle to the biomimetic design of micro/nano fabricated networks requires optimization of channels with arbitrary cross-sectional shape (not just circular) and smaller than is valid for Murray's original assumptions. We present a generalized law for symmetric branching that (a) is valid for any cross-sectional shape, providing that the shape is constant through the network; (b) is valid for slip flow and plug flow occurring at very small scales; and (c) is valid for networks with a constant depth, which is often a requirement for lab-on-a-chip fabrication procedures. By considering limits of the generalized law, we show that the optimum daughter-parent area ratio Γ, for symmetric branching into N daughter channels of any constant cross-sectional shape, is Γ=N−2/3Γ=N−2/3 for large-scale channels, and Γ=N−4/5Γ=N−4/5 for channels with a characteristic length scale much smaller than the slip length. Our analytical results are verified by comparison with a numerical optimization of a two-level network model based on flow rate data obtained from a variety of sources, including Navier-Stokes slip calculations, kinetic theory data, and stochastic particle simulations

Mechanical properties of cancellous bone from the acetabulum in relation to acetabular shell fixation and compared with the corresponding femoral head

Acknowledgments We thank Phil Jackson for help sourcing donated cadavers and transportation of samples and Dr. F.R. Saunders for help with core preparation and advice. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewedPostprin

A study of the prompt and afterglow emission of the Short GRB 061201

Our knowledge of the intrinsic properties of short duration Gamma-Ray Bursts has relied, so far, only upon a few cases for which the estimate of the distance and an extended, multiwavelength monitoring of the afterglow have been obtained. We carried out multiwavelength observations of the short GRB 061201 aimed at estimating its distance and studying its properties. We performed a spectral and timing analysis of the prompt and afterglow emission and discuss the results in the context of the standard fireball model. A clear temporal break was observed in the X-ray light curve about 40 minutes after the burst trigger. We find that the spectral and timing behaviour of the X-ray afterglow is consistent with a jet origin of the observed break, although the optical data can not definitively confirm this and other scenarios are possible. No underlying host galaxy down to R~26 mag was found after fading of the optical afterglow. Thus, no secure redshift could be measured for this burst. The nearest galaxy is at z=0.111 and shows evidence of star formation activity. We discuss the association of GRB 061201 with this galaxy and with the ACO S 995 galaxy cluster, from which the source is at an angular distance of 17'' and 8.5', respectively. We also test the association with a possible undetected, positionally consistent galaxy at z~1. In all these cases, in the jet interpretation, we find a jet opening angle of 1-2 degrees.Comment: 10 pages, 7 figures, accepted for publication in A&

Photoelectron angular distributions from rotationally resolved autoionizing states of N2

The single-photon, photoelectron-photoion coincidence spectrum of N2 has been recorded at high (~1.5 cm–1 ) resolution in the region between the N2+ X 2Σg+, v+ = 0 and 1 ionization thresholds by using a double-imaging spectrometer and intense vacuum-ultraviolet light from the Synchrotron SOLEIL. This approach provides the relative photoionization cross section, the photoelectron energy distribution, and the photoelectron angular distribution as a function of photon energy. The region of interest contains autoionizing valence states, vibrationally autoionizing Rydberg states converging to vibrationally excited levels of the N2+ X 2Σg+ ground state, and electronically autoionizing states converging to the N2+ A 2Π and B 2Σu+ states. The wavelength resolution is sufficient to resolve rotational structure in the autoionizing states, but the electron energy resolution is insufficient to resolve rotational structure in the photoion spectrum. A simplified approach based on multichannel quantum defect theory is used to predict the photoelectron angular distribution parameters, β, and the results are in reasonably good agreement with experiment

Photoelectron angular distributions from rotationally resolved autoionizing states of N2

The single-photon, photoelectron-photoion coincidence spectrum of N2 has been recorded at high (~1.5 cm–1 ) resolution in the region between the N2+ X 2Σg+, v+ = 0 and 1 ionization thresholds by using a double-imaging spectrometer and intense vacuum-ultraviolet light from the Synchrotron SOLEIL. This approach provides the relative photoionization cross section, the photoelectron energy distribution, and the photoelectron angular distribution as a function of photon energy. The region of interest contains autoionizing valence states, vibrationally autoionizing Rydberg states converging to vibrationally excited levels of the N2+ X 2Σg+ ground state, and electronically autoionizing states converging to the N2+ A 2Π and B 2Σu+ states. The wavelength resolution is sufficient to resolve rotational structure in the autoionizing states, but the electron energy resolution is insufficient to resolve rotational structure in the photoion spectrum. A simplified approach based on multichannel quantum defect theory is used to predict the photoelectron angular distribution parameters, β, and the results are in reasonably good agreement with experiment

The interplay of microscopic and mesoscopic structure in complex networks

Not all nodes in a network are created equal. Differences and similarities exist at both individual node and group levels. Disentangling single node from group properties is crucial for network modeling and structural inference. Based on unbiased generative probabilistic exponential random graph models and employing distributive message passing techniques, we present an efficient algorithm that allows one to separate the contributions of individual nodes and groups of nodes to the network structure. This leads to improved detection accuracy of latent class structure in real world data sets compared to models that focus on group structure alone. Furthermore, the inclusion of hitherto neglected group specific effects in models used to assess the statistical significance of small subgraph (motif) distributions in networks may be sufficient to explain most of the observed statistics. We show the predictive power of such generative models in forecasting putative gene-disease associations in the Online Mendelian Inheritance in Man (OMIM) database. The approach is suitable for both directed and undirected uni-partite as well as for bipartite networks

A coding polymorphism in matrix metalloproteinase 9 reduces risk of scarring sequelae of ocular Chlamydia trachomatis infection.

BACKGROUND: Trachoma, an infectious disease of the conjunctiva caused by Chlamydia trachomatis, is an important global cause of blindness. A dysregulated extracellular matrix (ECM) proteolysis during the processes of tissue repair following infection and inflammation are thought to play a key role in the development of fibrotic sequelae of infection, which ultimately leads to blindness. Expression and activity of matrix metalloproteinase 9 (MMP-9), a major effector of ECM turnover, is up-regulated in the inflamed conjunctiva of trachoma subjects. Genetic variation within the MMP9 gene affects in vitro MMP9 expression levels, enzymatic activity and susceptibility to various inflammatory and fibrotic conditions. METHODS: We genotyped 651 case-control pairs from trachoma endemic villages in The Gambia for coding single nucleotide polymorphisms (SNPs) in the MMP9 gene using the high-throughput Sequenom system. Single marker and haplotype conditional logistic regression (CLR) analysis for disease association was performed. RESULTS: The Q279R mutation located in exon 6 of MMP9 was found to be associated with lower risk for severe disease sequelae of ocular Chlamydia trachomatis infection. This mutation, which leads to a nonsynonymous amino-acid change within the active site of the enzyme may reduce MMP-9-induced degradation of the structural components of the ECM during inflammatory episodes in trachoma and its associated fibrosis. CONCLUSION: This work supports the hypothesis that MMP-9 has a role in the pathogenesis of blinding trachoma