Galaxy luminosity functions at redshifts 0.6-1.2 in the Chandra Deep Field South

We present the rest-frame ultraviolet (UV) galaxy luminosity function (LF) and luminosity density (LD) measurements in the far-UV (1500 Å) wavelength, in the redshift range $z$ = 0.6-1.2. The UV LF is derived using XMM-Newton Optical Monitor (XMM-OM), UV (1600-4000 Å) observations of the Chandra Deep Field South, over an area of 396 arcmin2. Using the deep UV imaging of the CDFS, we identified >2500 galaxies in our sample with UVW1AB ≤ 24.5 mag. This sample, along with various other catalogues containing redshift information, is used to calculate the binned representation of the galaxy UV LF in the two redshift bins 0.6 ≤ $z$ < 0.8 and 0.8 ≤ $z$ < 1.2, having a wide range of 1500 Å rest-frame UV magnitudes (ΔM1500 3), reaching 1-1.5 magnitudes fainter than previous studies at similar redshifts. The binned LF is described well by the Schechter function form. Using maximum-likelihood, the Schechter function is fitted to the unbinned data to obtain the best-fitting values of the the UV galaxy LF parameters. We find that characteristic magnitude M∗ brightens by 0.8 mag from $z$ = 0.7 to $z$ = 1, implying an increase in the star formation activity between these redshifts, as reported by past studies. Our estimate of the faint-end slope-1.10+0.19-0.18 is on the shallower side compared with previous studies at z = 0.7, whereas a value of-1.56+0.19-0.18 estimated for $z$ = 1.0, agrees with previous results given the uncertainties

The calibration of read-out-streak photometry in the XMM-Newton Optical Monitor and the construction of a bright-source catalogue

The dynamic range of the XMM-Newton Optical Monitor (XMM-OM) is limited at the bright end by coincidence loss, the superposition of multiple photons in the individual frames recorded from its micro-channel-plate (MCP) intensified charge-coupled device (CCD) detector. One way to overcome this limitation is to use photons that arrive during the frame transfer of the CCD, forming vertical read-out streaks for bright sources. We calibrate these read-out streaks for photometry of bright sources observed with XMM-OM. The bright source limit for read-out streak photometry is set by the recharge time of the MCPs. For XMM-OM we find that the MCP recharge time is 0.55 ms. We determine that the effective bright limits for read-out streak photometry with XMM-OM are approximately 1.5 magnitudes brighter than the bright source limits for normal aperture photometry in full-frame images. This translates into bright-source limits in Vega magnitudes of UVW2=7.1, UVM2=8.0, UVW1=9.4, U=10.5, B=11.5, V=10.2 and White=12.5 for data taken early in the mission. The limits brighten by up to 0.2 magnitudes, depending on filter, over the course of the mission as the detector ages. The method is demonstrated by deriving UVW1 photometry for the symbiotic nova RR Telescopii, and the new photometry is used to constrain the e-folding time of its decaying UV emission. Using the read-out streak method, we obtain photometry for 50 per cent of the missing UV source measurements in version 2.1 of the XMM-Newton Serendipitous UV Source Survey (XMM-SUSS 2.1) catalogue

Exploring the canonical behaviour of long gamma-ray bursts using an intrinsic multiwavelength afterglow correlation

In this paper, we further investigate the relationship, reported by Oates et al., between the optical/UV afterglow luminosity (measured at restframe 200 s) and average afterglow decay rate (measured from restframe 200 s onwards) of long duration gamma-ray bursts (GRBs). We extend the analysis by examining the X-ray light curves, finding a consistent correlation. We therefore explore how the parameters of these correlations relate to the prompt emission phase and, using a Monte Carlo simulation, explore whether these correlations are consistent with predictions of the standard afterglow model. We find significant correlations between: log  LO, 200 s and log  LX, 200 s; αO, >200 s and αX, >200 s, consistent with simulations. The model also predicts relationships between log Eiso and log  L200 s; however, while we find such relationships in the observed sample, the slope of the linear regression is shallower than that simulated and inconsistent at ≳3σ. Simulations also do not agree with correlations observed between log  L200 s and α> 200 s, or logEiso logEiso and α> 200 s. Overall, these observed correlations are consistent with a common underlying physical mechanism producing GRBs and their afterglows regardless of their detailed temporal behaviour. However, a basic afterglow model has difficulty explaining all the observed correlations. This leads us to briefly discuss alternative more complex models

Use of a nested PCR-enzyme immunoassay with an internal control to detect Chlamydophila psittaci in turkeys

BACKGROUND: Laboratory diagnosis of Chlamydophila psittaci, an important turkey respiratory pathogen, is difficult. To facilitate the diagnosis, a nested PCR-enzyme immunoassay (PCR-EIA) was developed to detect the Cp. psittaci outer membrane protein A (ompA) gene in pharyngeal swabs. METHODS: The fluorescein-biotin labelled PCR products were immobilized on streptavidin-coated microtiter plates and detected with anti-fluorescein peroxidase conjugate and a colorimetric substrate. An internal inhibition control was included to rule out the presence of inhibitors of DNA amplification. The diagnostic value of the ompA nested PCR-EIA in comparison to cell culture and a 16S-rRNA based nested PCR was assessed in pharyngeal turkey swabs from 10 different farms experiencing respiratory disease. RESULTS: The sensitivity of the nested PCR-EIA was established at 0.1 infection forming units (IFU). Specificity was 100%. The ompA nested PCR-EIA was more sensitive than the 16S-rRNA based nested PCR and isolation, revealing 105 out of 200 (52.5%) positives against 13 and 74 for the latter two tests, respectively. Twenty-nine (23.8%) out of 122 ompA PCR-EIA negatives showed the presence of inhibitors of DNA amplification, although 27 of them became positive after diluting (1/10) the specimens in PCR buffer or after phenol-chloroform extraction and subsequent ethanol precipitation. CONCLUSION: The present study stresses the need for an internal control to confirm PCR true-negatives and demonstrates the high prevalence of chlamydiosis in Belgian turkeys and its potential zoonotic risk. The ompA nested PCR-EIA described here is a rapid, highly sensitive and specific diagnostic assay and will help to facilitate the diagnosis of Cp. psittaci infections in both poultry and man

Sedentary time and markers of inflammation in people with newly diagnosed type 2 diabetes

This is the final version. Available on open access from Elsevier via the DOI in this recordBACKGROUND AND AIMS: We investigated whether objectively measured sedentary time was associated with markers of inflammation in adults with newly diagnosed type 2 diabetes. METHODS AND RESULTS: We studied 285 adults (184 men, 101 women, mean age 59.0 ± 9.7) who had been recruited to the Early ACTivity in Diabetes (Early ACTID) randomised controlled trial. C-reactive protein (CRP), adiponectin, soluble intracellular adhesion molecule-1 (sICAM-1), interleukin-6 (IL-6), and accelerometer-determined sedentary time and moderate-vigorous physical activity (MVPA) were measured at baseline and after six-months. Linear regression analysis was used to investigate the independent cross-sectional and longitudinal associations of sedentary time with markers of inflammation. At baseline, associations between sedentary time and IL-6 were observed in men and women, an association that was attenuated following adjustment for waist circumference. After 6 months of follow-up, sedentary time was reduced by 0.4 ± 1.2 h per day in women, with the change in sedentary time predicting CRP at follow-up. Every hour decrease in sedentary time between baseline and six-months was associated with 24% (1, 48) lower CRP. No changes in sedentary time between baseline and 6 months were seen in men. CONCLUSIONS: Higher sedentary time is associated with IL-6 in men and women with type 2 diabetes, and reducing sedentary time is associated with improved levels of CRP in women. Interventions to reduce sedentary time may help to reduce inflammation in women with type 2 diabetes.National Institute for Health Research (NIHR

Exploring the canonical behaviour of long gamma-ray bursts with an intrinsic multiwavelength afterglow correlation

In this conference proceeding we examine a correlation between the afterglow luminosity (measured at restframe 200 s; logL200s) and average afterglow decay rate (measured from restframe 200 s onwards; α>200s) found in both the optical/UV and X-ray afterglows of long duration Gamma-ray Bursts (GRBs). Examining the X-ray light curves, we find the correlation does not depend on the presence of specific light curve features. We explore how the parameters in the optical/UV and X-ray bands relate to each other and to the prompt emission phase. We also use a Monte Carlo simulation to explore whether these relationships are consistent with predictions of the standard afterglow model. We conclude that the correlations are consistent with a common underlying physical mechanism producing GRBs and their afterglows regardless of their detailed temporal behaviour. However, a basic afterglow model has difficulty explaining correlations involving α>200s. We therefore briefly discuss alternative more complex models

A novel methodology for identifying environmental exposures using GPS data

Aim: While studies using global positioning systems (GPS) have the potential to refine measures of exposure to the neighbourhood environment in health research, one limitation is that they do not typically identify time spent undertaking journeys in motorised vehicles when contact with the environment is reduced. This paper presents and tests a novel methodology to explore the impact of this concern. Methods: Using a case study of exposure assessment to food environments, an unsupervised computational algorithm is employed in order to infer two travel modes: motorised and non-motorised, on the basis of which trips were extracted. Additional criteria are imposed in order to improve robustness of the algorithm. Results: After removing noise in the GPS data and motorised vehicle journeys, 82.43% of the initial GPS points remained. In addition, after comparing a sub-sample of trips classified visually of motorised, non-motorised and mixed mode trips with the algorithm classifications, it was found that there was an agreement of 88%. The measures of exposure to the food environment calculated before and after algorithm classification were strongly correlated. Conclusion: Identifying non-motorised exposures to the food environment makes little difference to exposure estimates in urban children but might be important for adults or rural populations who spend more time in motorised vehicles.APJ was partially supported by the Centre for Diet and Activity Research (CEDAR), a UK Clinical Research Collaboration Public Health Research Centre of Excellence. Funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, National Institute for Health Research and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged

Chiral tunneling and the Klein paradox in graphene

The so-called Klein paradox - unimpeded penetration of relativistic particles through high and wide potential barriers - is one of the most exotic and counterintuitive consequences of quantum electrodynamics (QED). The phenomenon is discussed in many contexts in particle, nuclear and astro- physics but direct tests of the Klein paradox using elementary particles have so far proved impossible. Here we show that the effect can be tested in a conceptually simple condensed-matter experiment by using electrostatic barriers in single- and bi-layer graphene. Due to the chiral nature of their quasiparticles, quantum tunneling in these materials becomes highly anisotropic, qualitatively different from the case of normal, nonrelativistic electrons. Massless Dirac fermions in graphene allow a close realization of Klein's gedanken experiment whereas massive chiral fermions in bilayer graphene offer an interesting complementary system that elucidates the basic physics involved.Comment: 15 pages, 4 figure

Localization of ultrasound in a three-dimensional elastic network

After exactly half a century of Anderson localization, the subject is more alive than ever. Direct observation of Anderson localization of electrons was always hampered by interactions and finite temperatures. Yet, many theoretical breakthroughs were made, highlighted by finite-size scaling, the self-consistent theory and the numerical solution of the Anderson tight-binding model. Theoretical understanding is based on simplified models or approximations and comparison with experiment is crucial. Despite a wealth of new experimental data, with microwaves, light, ultrasound and cold atoms, many questions remain, especially for three dimensions. Here we report the first observation of sound localization in a random three-dimensional elastic network. We study the time-dependent transmission below the mobility edge, and report ``transverse localization'' in three dimensions, which has never been observed previously with any wave. The data are well described by the self-consistent theory of localization. The transmission reveals non-Gaussian statistics, consistent with theoretical predictions.Comment: Final published version, 5 pages, 4 figure