Evolution of the 1.4 GHz Radio Luminosity Function

The results of an optical and infrared investigation of a complete sub-sample of the Leiden-Berkeley Deep Survey (flux > 1 mJy at 1.4 GHz) are presented. Optical counterparts have been identified for 69 of the 73 sources in the two Hercules fields, and redshifts obtained for 49 of them. Photometric redshifts are computed from the g,r,i,K data for the remaining 21 sources. This complete sample is compared with the radio luminosity functions (RLFs) of Dunlop and Peacock (1990). The RLF models successfully trace the evolution of the radio sources with redshift, but there is some disagreement between the luminosity-dependence of the models and the data. The observed RLF for the lower luminosity population (log P < 26) shows evidence for a cut-off at lower redshifts (z=0.5-1.5) than for the more powerful objects.Comment: To appear in "After the Dark Ages: When Galaxies Were Young (the Universe at 2 < z < 5)", University of Maryland, October 1998, S. S. Holt and E. P. Smith (eds), (AIP), 4 pages, 4 figures, uses aipproc.sty and epsfig.st

Weathering the storm: developments in the acoustic sensing of wind and rain

An Acoustic Rain Gauge (ARG) analyses the underwater sound levels across a wide frequency range, classifies the observed spectrum according to likely source and then determines the local wind speed or rain rate as appropriate. Thispaper covers a trial on the Scotian Shelf off Canada, comparing the geophysical information derived from the acoustic signals with those obtained from other sources

Identification of novel candidate genes for follicle selection in the broiler breeder ovary

BACKGROUND: Broiler breeders fed ad libitum are characterised by multiple ovulation, which leads to poor shell quality and egg production. Multiple ovulation is controlled by food restriction in commercial flocks. However, the level of food restriction raises welfare concerns, including that of severe hunger. Reducing the rate of multiple ovulation by genetic selection would facilitate progress towards developing a growth profile for optimum animal welfare. RESULTS: The study utilised 3 models of ovarian follicle development; laying hens fed ad libitum (experiment 2) and broiler breeders fed ad libitum or a restricted diet (experiments 1 & 3). This allowed us to investigate gene candidates for follicular development by comparing normal, abnormal and “controlled” follicle hierarchies at different stages of development. Several candidate genes for multiple ovulation were identified by combining microarray analysis of restricted vs. ad libitum feeding, literature searches and QPCR expression profiling throughout follicle development. Three candidate genes were confirmed by QPCR as showing significant differential expression between restricted and ad libitum feeding: FSHR, GDF9 and PDGFRL. PDGFRL, a candidate for steroidogenesis, showed significantly up-regulated expression in 6–8 mm follicles of ad libitum fed broiler breeders (P = 0.016), the period at which follicle recruitment occurs. CONCLUSIONS: Gene candidates have been identified and evidence provided to support a possible role in regulation of ovarian function and follicle number. Further characterisation of these genes will be required to assess their potential for inclusion into breeding programmes to improve the regulation of follicle selection and reduce the need for feed restriction

Quasi-experimental study designs series –Paper 9: Collecting data from quasi-experimental studies

Objective: To identify variables that must be coded when synthesizing primary studies that use quasi-experimental designs.  Study Design and Setting: All quasi-experimental (QE) designs.  Results: When designing a systematic review of QE studies potential sources of heterogeneity – both theory-based and methodological – must be identified. We outline key components of inclusion criteria for syntheses of quasi-experimental studies. We provide recommendations for coding content-relevant and methodological variables, and outlined the distinction between bivariate effect sizes and partial (i.e., adjusted) effect sizes. Designs used and controls employed are viewed as of greatest importance. Potential sources of bias and confounding are also addressed.  Conclusion: Careful consideration must be given to inclusion criteria and the coding of theoretical and methodological variables during the design phase of a synthesis of quasi-experimental studies. The success of the meta-regression analysis relies on the data available to the meta-analyst. Omission of critical moderator variables (i.e., effect modifiers) will undermine the conclusions of a meta-analysis

The cosmological evolution of galaxies

The results of an extensive optical and infrared investigation of a complete sub-sample of the Leiden-Berkeley Deep Survey of radio sources at 1.4 GHz are presented. Optical coun­terparts have been identified for 69 of the 73 sources in the two Hercules fields, and redshifts obtained for 49 of them. Photometric redshifts are computed from the griK data for the remaining 20 sources.Redshifts have been measured for fifteen sources in the brighter Parkes Selected Regions radio survey, in order to test the accuracy of redshift estimates based on the K -z relation for brighter radio sources. The results enhance the evidence for a high-redshift cut-off in the2.7 GHz radio luminosity function.The data from the LBDS Hercules sample is compared with the radio luminosity func­tions (RLFs) of Dunlop and Peacock (1990). Two of the RLF models successfully trace the evolution of the radio sources with redshift, but there is some disagreement between the luminosity-dependence of the models and the data. The observed RLF for the lower lumi­nosity population (log10 P2.7 < 26) shows evidence for a cut-off at lower redshifts (z ~ 0.5-1.5) than for the more powerful objects in the Parkes Selected Regions survey.The spectral evolution of these radio sources is investigated, with particular emphasis on modelling the red envelope of galaxies. Together with a sample of passively-evolving galaxies believed to be at z ~ 2.4, these data are used to show that the oldest galaxies at high- redshift are incompatable with a critical-density (Ho = 1) universe, unless there is a significant cosmological constant

Angular clustering of galaxies at 3.6 microns from the Spitzer Wide-area Infrared Extragalactic (SWIRE) Survey

We present the first analysis of large-scale clustering from the Spitzer Wide-area Infrared Extragalactic legacy survey (SWIRE). We compute the angular correlation function of galaxies selected to have 3.6 m fluxes brighter than 32 Jy in three fields totaling 2 deg2 in area. In each field we detect clustering with a high level of significance. The amplitude and slope of the correlation function is consistent between the three fields and is modeled as w() ¼ A1 with A ¼ (0:6 0:3) ; 10 3; ¼ 2:03 0:10. With a fixed slope of ¼ 1:8, we obtain an amplitude of A ¼ (1:7 0:1) ; 10 3. Assuming an equivalent depth of K 18:7 mag we find that our errors are smaller but our results are consistent with existing clustering measurements in K-band surveys and with stable clustering models. We estimate our median redshift z ’ 0:75, and this allows us to obtain an estimate of the three-dimensional correlation function (r), for which we find r0 ¼ 4:4 0:1 h 1 Mpc

7 Essays on Impact

Edited by Dr Andrew Dean, Dr Michael Wykes & Hilary Stevens, University of ExeterThrough the Jisc-funded DESCRIBE Project we have sought to undertake a rigorous assessment of current standards relating to the evidence of impacts arising from Higher Education research. This document contains seven valuable essays each exploring the topic of Impact. Each essay is distinct and we have sought to enable selected thought-leaders and Impact experts to both review the status quo, and to look to the future, making suggestions and recommendations for the development of Impact in the sector. DESCRIBE has been managed by the University of Exeter’s Research and Knowledge Transfer team in partnership with the Marchmont Observatory. We have sought to combine the latest thinking on research Impact with examples and recommendations which are practical and rooted in the art of the possible.JISC DIINN1