9,197 research outputs found

    Near-Infrared Observations of the Environments of Radio Quiet QSOs at z >~ 1

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    We present the results of an infrared survey of QSO fields at z=0.95, 0.995 and 1.5. Each z<1 field was imaged to typical continuum limits of J=20.5, Kprime=19 (5 sigma), and line fluxes of 1.3E10{-16}ergs/cm^2/s (1 sigma)in a 1% interference filter. 16 fields were chosen with z~0.95 targets, 14 with z~0.995 and 6 with z~1.5. A total area of 0.05 square degrees was surveyed, and two emission-line objects were found. We present the infrared and optical photometry of these objects. Optical spectroscopy has confirmed the redshift of one object (at z=0.989) and is consistent with the other object having a similar redshift. We discuss the density of such objects across a range of redshifts from this survey and others in the literature. We also present number-magnitude counts for galaxies in the fields of radio quiet QSOs, supporting the interpretation that they exist in lower density environments than their radio loud counterparts. The J-band number counts are among the first to be published in the J=16--20.Comment: 34 pages, including 12 figures; accepted for publication in the Ap

    Infrared images of merging galaxies

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    Infrared imaging of interacting galaxies is especially interesting because their optical appearance is often so chaotic due to extinction by dust and emission from star formation regions, that it is impossible to locate the nuclei or determine the true stellar distribution. However, at near-infrared wavelengths extinction is considerably reduced, and most of the flux from galaxies originates from red giant stars that comprise the dominant stellar component by mass. Thus near infrared images offer the opportunity to study directly components of galactic structure which are otherwise inaccessible. Such images may ultimately provide the framework in which to understand the activity taking place in many of the mergers with high Infrared Astronomy Satellite (IRAS) luminosities. Infrared images have been useful in identifying double structures in the nuclei of interacting galaxies which have not even been hinted at by optical observations. A striking example of this is given by the K images of Arp 220. Graham et al. (1990) have used high resolution imaging to show that it has a double nucleus coincident with the radio sources in the middle of the dust lane. The results suggest that caution should be applied in the identification of optical bright spots as multiple nuclei in the absence of other evidence. They also illustrate the advantages of using infrared imaging to study the underlying structure in merging galaxies. The authors have begun a program to take near infrared images of galaxies which are believed to be mergers of disk galaxies because they have tidal tails and filaments. In many of these the merger is thought to have induced exceptionally luminous infrared emission (cf. Joseph and Wright 1985, Sanders et al. 1988). Although the optical images of the galaxies show spectacular dust lanes and filaments, the K images all have a very smooth distribution of light with an apparently single nucleus

    Biological Records Centre Annual Report 2005-2006

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    The period covered by this report is the first year of a new six-year partnership between CEH and JNCC. For this period, there is increased emphasis on targeted survey, on analysis and interpretation and on communications and outreach. These activities were always part of BRC’s work, but they have been given greater prominence as a result of rapid developments in information technology. Data are increasingly reaching BRC in electronic form, so that the effort of data entry and collation is reduced. The data, collected by many volunteers and then collated and analysed at BRC, document the changing status and distribution of plants and animals in Britain. Distribution maps are published in atlases and are available via the internet through the NBN Gateway. The effects of change or loss of habitats, the influence of climate change and the consequences of changing water quality are all examples of the environmental factors that affect our biodiversity and which BRC aims to document and understand. The results are vital for developing environmental policies, to support conservation, and for fundamental ecological research. BRC is funded jointly by JNCC and NERC through a partnership based on a Memorandum of Agreement (MoA). The partnership started in 1973 when the Nature Conservancy was divided to form the successor bodies Nature Conservancy Council (NCC) and Institute of Terrestrial Ecology (ITE). NCC was in turn divided further to form JNCC and three Country Agencies, while ITE was merged with other NERC units to form CEH. Through all these changes, the partnership has been maintained. A six-year memorandum of agreement ended on 31 January 2005 (Hill et al. 2005). The present report covers the first full year, 2005-6, of the new agreement for 2005-2010. Rapid progress in information technology continues to be highly beneficial for BRC, whose data are increasingly used by the UK country conservation agencies, environmental consultants, NGOs, research workers, policy makers and volunteers. It is gratifying to know that, through our ability to display data on the National Biodiversity Network (NBN) Gateway, some of our data suppliers now have immediate access to their own data in a convenient form. The year 2005-6 has been one of steady progress, with new datasets added to BRC, substantial additions to existing data, and improved communication with the NBN Gateway. The most high profile activity of the year has been the Harlequin Ladybird Survey, which has enabled us to observe the early stages of colonization by a mobile insect in greater detail than has been possible in any previous case

    Stationary axisymmetric exteriors for perturbations of isolated bodies in general relativity, to second order

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    Perturbed stationary axisymmetric isolated bodies, e.g. stars, represented by a matter-filled interior and an asymptotically flat vacuum exterior joined at a surface where the Darmois matching conditions are satisfied, are considered. The initial state is assumed to be static. The perturbations of the matching conditions are derived and used as boundary conditions for the perturbed Ernst equations in the exterior region. The perturbations are calculated to second order. The boundary conditions are overdetermined: necessary and sufficient conditions for their compatibility are derived. The special case of perturbations of spherical bodies is given in detail.Comment: RevTeX; 32 pp. Accepted by Phys. Rev. D. Added references and extra comments in introductio

    Spectropolarimetry of the H-alpha line in Herbig Ae/Be stars

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    Using the HiVIS spectropolarimeter built for the Haleakala 3.7m AEOS telescope, we have obtained a large number of high precision spectropolarimetrc observations (284) of Herbig AeBe stars collected over 53 nights totaling more than 300 hours of observing. Our sample of five HAeBe stars: AB Aurigae, MWC480, MWC120, MWC158 and HD58647, all show systematic variations in the linear polarization amplitude and direction as a function of time and wavelength near the H-alpha line. In all our stars, the H-alpha line profiles show evidence of an intervening disk or outflowing wind, evidenced by strong emission with an absorptive component. The linear polarization varies by 0.2% to 1.5% with the change typically centered in the absorptive part of the line profile. These observations are inconsistent with a simple disk-scattering model or a depolarization model which produce polarization changes centered on the emmissive core. We speculate that polarized absorption via optical pumping of the intervening gas may be the cause.Comment: Accepted for publication in ApJ Letter

    A temperature dependent virus binding assay reveals the presence of neutralising antibodies in human cytomegalovirus gB vaccine recipients’ sera

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    Human cytomegalovirus (HCMV) remains an important cause of mortality in immune-compromised transplant patients and following congenital infection. Such is the burden, an effective vaccine strategy is considered to be of the highest priority. The most successful vaccines to date have focused on generating immune responses against glycoprotein B (gB) – a protein essential for HCMV fusion and entry. We have previously reported that an important component of the humoral immune response elicited by gB/MF59 vaccination of patients awaiting transplant is the induction of non-neutralizing antibodies that target cell-associated virus with little evidence of concomitant classical neutralizing antibodies. Here we report that a modified neutralization assay that promotes prolonged binding of HCMV to the cell surface reveals the presence of neutralizing antibodies in sera taken from gB-vaccinated patients that cannot be detected using standard assays. We go on to show that this is not a general feature of gB-neutralizing antibodies, suggesting that specific antibody responses induced by vaccination could be important. Although we can find no evidence that these neutralizing antibody responses are a correlate of protection in vivo in transplant recipients their identification demonstrates the utility of the approach in identifying these responses. We hypothesize that further characterization has the potential to aid the identification of functions within gB that are important during the entry process and could potentially improve future vaccine strategies directed against gB if they prove to be effective against HCMV at higher concentrations

    Robotic-arm assisted versus conventional unicompartmental knee arthroplasty : exploratory secondary analysis of a Randomised Controlled Trial

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    Objectives: This study reports on a secondary exploratory analysis of the early clinical outcomes of an randomised clinical trial comparing Robotic-arm Assisted Uni-compartmental Knee Arthroplasty (UKA) for medial compartment osteoarthritis of the knee compared to Manual UKA performed using traditional surgical jigs. This follows reporting of primary outcomes of implant accuracy and gait analysis that showed significant advantages in the Robotic-arm assisted group.Methods139 patients were recruited from a single centre. Patients were randomised to receive either a manual UKA implanted with the aid of traditional surgical jigs, or a UKA implanted with the aid of a tactile guided Robotic-arm Assisted system. Outcome measures included: American Knee Society Score (AKSS), Oxford Knee Score (OKS), Forgotten Joint Score (FJS), Hospital Anxiety Depression (HAD) Scale, University of California at Los Angeles (UCLA) Activity Scale, SF-12, Pain Catastrophising Scale (PCS), Somatic Disease (Primary care evaluation of mental disorders [PRIME-MD] score), Pain Visual Analogue Scale (VAS), Analgesic use, Patient Satisfaction, complications relating to surgery, 90 day Pain diaries and the requirement for revision surgery.ResultsFrom day 1 post-operation through to week 8 post-operation the median pain scores for Robotic-arm Assisted group were 55.4% lower than those observed in the Manual surgery group (p = 0.040). A greater proportion of patients receiving Robotic-arm Assisted surgery improved their UCLA activity score.At 3 months post-operation, the Robotic-arm Assisted group had better AKSS scores (Robotic median 164 (Quarter 1 131, Quarter 3 178), Manual 143 (Quarter 1 132, Quarter 3 166)), although no difference was noted with the OKS.At 1 year post-operation, the observed differences with the AKSS had narrowed from 21 points to 7 points (p = 0.106) (Robotic median=171 (Quarter 1 153, Quarter 3 179), Manual median=164 (Quarter 1 144, Quarter 3 182 No difference was observed with the OKS, and almost half of each group reached the ceiling limit of the score (OKS > 43).The key factors associated with achieving excellent outcome on the AKSS were a pre-operative activity level > 5 on the UCLA activity score and use of Robotic-arm surgery. Factors associated with a poor outcome were manual surgery and pre-operative depression.Conclusions: Robotic-arm assisted surgery results in improved early pain scores and early function scores in some patient reported outcomes measures, but no difference was observed, at 1 year post operatively. Although improved results favoured the Robotic arm assisted group in active patients (i.e. UCLA > = 5), these do not withstand more stringent multiplicity adjustments

    The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth

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    We have obtained the first detection of spectral absorption lines in one of the high-velocity stars in the vicinity of the Galaxy's central supermassive black hole. Both Brgamma (2.1661 micron) and He I (2.1126 micron) are seen in absorption in S0-2 with equivalent widths (2.8+-0.3 Ang & 1.7+-0.4 Ang) and an inferred stellar rotational velocity (220+-40 km/s) that are consistent with that of an O8-B0 dwarf, which suggests that it is a massive (~15 Msun), young (<10 Myr) main sequence star. This presents a major challenge to star formation theories, given the strong tidal forces that prevail over all distances reached by S0-2 in its current orbit (130 - 1900 AU) and the difficulty in migrating this star inward during its lifetime from further out where tidal forces should no longer preclude star formation. The radial velocity measurements (-510+-40 km/s) and our reported proper motions for S0-2 strongly constrain its orbit, providing a direct measure of the black hole mass of 4.1(+-0.6)x10^6(Ro/8kpc)^3 Msun. The Keplerian orbit parameters have uncertainities that are reduced by a factor of 2-3 compared to previously reported values and include, for the first time, an independent solution for the dynamical center; this location, while consistent with the nominal infrared position of Sgr A*, is localized to a factor of 5 more precisely (+-2 milli-arcsec). Furthermore, the ambiguity in the inclination of the orbit is resolved with the addition of the radial velocity measurement, indicating that the star is behind the black hole at the time of closest approach and counter-revolving against the Galaxy. With further radial velocity measurements in the next few years, the orbit of S0-2 will provide the most robust estimate of the distance to the Galactic Center.Comment: 14 pages, Latex, Accepted for Publication in ApJ Letter

    Uneven Relationalities, Collective Biography, and Sisterly Affect in Neoliberal Universities

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    This article deploys a collective biographical methodology as a political and epistemological intervention in order to explore the emotional and affective politics of academic work for women in neoliberal universities. The managerial practices of contemporary universities tend to elevate disembodied reason over emotion; to repress, commodify, or co-opt emotional and affective labor; to increase individualization and competition among academic workers; and to disregard the relational work that the article suggests is essential for well-being at work. The apparent marginalization of feminist and feminine ways of being, thinking, and feeling in academia is examined through close readings of three narrative vignettes, which are based on memories of the everyday academic spaces of meetings, workshops, and mentoring. These stories explore moments of the breaking of ties among women and between men and women, as well as document how feminist relationalities can bind and exclude. The article suggests that academic ties are both part of the problem and the solution to countering neoliberal policies, and that academic relationships, especially with other women, are often experienced as unrealized spaces of hope. Building on feminist scholarship about race and diversity, the article reflects on how relational practices like collective biography create both inclusions and exclusions. Nevertheless, it suggests that the methodology of collective biography might engender more sustainable and ethical ways of being in academic workplaces because it provides the resources to begin to create a new collective imaginary of academia

    Smart Focal Plane Technologies for VLT Instruments

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    As we move towards the era of ELTs, it is timely to think about the future role of the 8-m class telescopes. Under the OPTICON programme, novel technologies have been developed that are intended for use in multi-object and integral-field spectrographs. To date, these have been targeted at instrument concepts for the European ELT, but there are also significant possibilities for their inclusion in new VLT instruments, ensuring the continued success and productivity of these unique telescopes.Comment: 5 pages, to appear in the proceedings of the ESO Workshop "Science with the VLT in the ELT era
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