463 research outputs found
Optical spectroscopy of radio galaxies in the 7C Redshift Survey
We present optical spectroscopy of all 49 radio galaxies in the 7C-I and
7C-II regions of the 7C Redshift Survey (7CRS). The low-frequency (151 MHz)
selected 7CRS sample contains all sources with flux-densities S_151 > 0.5 Jy in
three regions of the sky; 7C-I and 7C-II were chosen to overlap with the 5C6
and 5C7 surveys respectively, and cover a total sky area of 0.013 sr. The
sample has been completely identified and spectroscopy of the quasars and
broad-lined radio galaxies has been presented in Willott et al. (1998). Only
seven of the radio galaxies do not have redshift determinations from the
spectroscopy, giving a redshift completeness for the sample of >90%. The median
redshift of the 7CRS is 1.1. We present a composite 0.2<z<0.8 7CRS radio galaxy
spectrum and investigate the strengths of the 4000 Angstrom breaks in these
radio galaxies. We find an anti-correlation between the 4000 Angstrom break
strength and emission line luminosity, indicating that departures from old
elliptical galaxy continuum shapes are most likely due to non-stellar emission
associated with the active nucleus.Comment: 14 pages, 6 figures, MNRAS in pres
Behaviour and process in the formation of the North European Acheulean record: Towards a Unified Palaeolithic Landscape Approach
The Acheulean record of northern France and southern Britain has long been acknowledged as internationally important, having played an important historical role in the development of the discipline. Abundant artefacts have been recovered, primarily from fluvial gravel archives, allowing the responses of Middle Pleistocene human populations on the edge of their geographical distribution to be interrogated. The richness of the record from such deposits can most simply be read as reflecting absolute population numbers â and changes in this over time. However, factors such as regional super-abundance of high quality flint (related to solid geology) and intensity of aggregate exploitation also played their part in generating the apparently regionally dense record of finds. This paper investigates the inter-related patterns of human behaviour, preservation, artefact release and research tradition which underpin these basic distribution maps. We here present a framework for understanding the processes which have created the current distribution map â in terms of where we find material, and which periods are best represented within it. We term this the Unified Palaeolithic Landscape Approach and outline ways in which the spatial and temporal range of the Acheulean record can be addressed through the archaeological record of its heartland
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With flying colours: pilot performance with colour-coded head-up flight symbology
The manipulation of colour in display symbology design has long been recognised as a method to improve operator experience and performance. Recent developments in colour head-up display (HUD) and helmet-mounted display (HMD) technology underline the necessity to understand the human factors considerations of symbology colour coding against conventional monochrome symbology formats. In this low-fidelity desktop human-in-the-loop experiment, the colour of flight symbology on an overlaid symbology set was coded as a redundant cue to indicate the accuracy of professional and non-professional pilotsâ flight profile across a range of simulated flight manoeuvres. The main finding of this study was that colour coding flight symbology supported the manual flying performance of both professional and non-professional pilots. Notably, colour-coding of the bank indicator and airspeed tape minimised performance error during turning and altitude change manoeuvres, respectively. The usability of colour coded symbology was also rated higher than the monochrome symbology. We conclude that colour coded HUD/HMD symbology is preferred by the user and may improve performance during low workload manual flying tasks. A fuller understanding of performance and workload effects will require future studies to employ higher workload flying tasks and examine the utility of colour coding within higher fidelity environments
Observation of Spin-glass-like Behavior in SrRuO3 Epitaxial Thin Films
We report the observation of spin-glass-like behavior and strong magnetic
anisotropy in extremely smooth (~1-3 \AA) roughness) epitaxial (110) and (010)
SrRuO3 thin films. The easy axis of magnetization is always perpendicular to
the plane of the film (unidirectional) irrespective of crystallographic
orientation. An attempt has been made to understand the nature and origin of
spin-glass behavior, which fits well with Heisenberg model.Comment: 5 pages, 5 Figure
Therapist Experiences of Congruence in School-Based Counselling
Congruence is a key counselling concept, cited as the most important of the therapist provided conditions (Rogers, 1967). Whilst literature on congruence and its use within the therapeutic relationship is rich, there is a lack of research exploring how counsellors understand and experience congruence with children in school-based counselling programmes. This study explored how counsellors perceive, experience, and offer congruence with children in school-based counselling. Using phenomenology and hermeneutics as a philosophical basis, semi-structured interviews were conducted with three person-centred counsellors and one integrative counsellor who currently work with children in a school-based counselling service. The data was analysed using interpretative phenomenological analysis (IPA). This analysis found the following themes: (1) Intrapersonal Congruence and (2) Navigating Multiple Terrains. Participants identified intrapersonal congruence of paramount importance when working with children. Moments of insightful non-disclosure of therapist process are common and serve to enhance the therapeutic relationship with children. The âselfâ of the therapist, and the presence of certain aspects of self in the therapy room, can impact upon congruence. Therapist personal self-disclosure was essential in facilitating a strong therapeutic alliance with children; this paper argues it should be considered a central aspect of congruence with children. Finally, lack of clarity around the unique roles and responsibilities of working in a school setting as a counsellor affected the way therapists experience and offer congruence with children and young people. Implications for training and practice are also considered
A map of OMC-1 in CO 9-8
The distribution of 12C16O J=9-8 (1.037 THz) emission has been mapped in
OMC-1 at 35 points with 84" resolution. This is the first map of this source in
this transition and only the second velocity-resolved ground-based observation
of a line in the terahertz frequency band. There is emission present at all
points in the map, a region roughly 4' by 6' in size, with peak antenna
temperature dropping only near the edges. Away from the Orion KL outflow, the
velocity structure suggests that most of the emission comes from the OMC-1
photon-dominated region, with a typical linewidthof 3-6 km/s. Large velocity
gradient modeling of the emission in J=9-8 and six lower transitions suggests
that the lines originate in regions with temperatures around 120 K and
densities of at least 10^(3.5) cm^(-3) near theta^(1) C Ori and at the Orion
Bar, and from 70 K gas at around 10^(4) cm^(-3) southeast and west of the bar.
These observations are among the first made with the 0.8 m Smithsonian
Astrophysical Observatory Receiver Lab Telescope, a new instrument designed to
observe at frequencies above 1 THz from an extremely high and dry site in
northern Chile.Comment: Minor changes to references, text to match ApJ versio
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Atmospheric Phase Correction Using Total Power Radiometry at the Submillimeter Array
Phase noise caused by an inhomogeneous, time-variable water vapor distribution in our atmosphere reduces the angular resolution, visibility amplitude and coherence time of millimeter and submillimeter wavelength interferometers. We present early results from our total power radiometry phase correction experiment carried out with the Submillimeter Array on Mauna Kea. From accurate measurements of the atmospheric emission along the lines of sight of two elements of the array, we estimated the differential atmospheric electrical path between them. In one test, presented here, the phase correction technique reduced the rms phase noise at 230 GHz from 72⊠to 27⊠over a 20 minute period with a 2.5 second integration time. This corresponds to a residual differential electrical path of 98 ”m, or 15 ”m of precipitable water vapor, and raises the coherence in the 20 minute period from 0.45 to 0.9.AstronomyPhysic
Engineering Archeal Surrogate Systems for the Development of Protein-Protein Interaction Inhibitors against Human RAD51
Protein-protein interactions (PPIs) are increasingly important targets for drug discovery. Efficient fragment-based drug discovery approaches to tackle PPIs are often stymied by difficulties in the production of stable, unliganded target proteins. Here, we report an approach that exploits protein engineering to "humanise" thermophilic archeal surrogate proteins as targets for small-molecule inhibitor discovery and to exemplify this approach in the development of inhibitors against the PPI between the recombinase RAD51 and tumour suppressor BRCA2. As human RAD51 has proved impossible to produce in a form that is compatible with the requirements of fragment-based drug discovery, we have developed a surrogate protein system using RadA from . Using a monomerised RadA as our starting point, we have adopted two parallel and mutually instructive approaches to mimic the human enzyme: firstly by mutating RadA to increase sequence identity with RAD51 in the BRC repeat binding sites, and secondly by generating a chimeric archaeal human protein. Both approaches generate proteins that interact with a fourth BRC repeat with affinity and stoichiometry comparable to human RAD51. Stepwise humanisation has also allowed us to elucidate the determinants of RAD51 binding to BRC repeats and the contributions of key interacting residues to this interaction. These surrogate proteins have enabled the development of biochemical and biophysical assays in our ongoing fragment-based small-molecule inhibitor programme and they have allowed us to determine hundreds of liganded structures in support of our structure-guided design process, demonstrating the feasibility and advantages of using archeal surrogates to overcome difficulties in handling human proteins.Wellcome Trust Translational (Grant ID: 080083/Z/06/Z) and Seeding Drug Discovery Initiative (Grant ID: 91050/Z/10/Z) award
Atmospheric Phase Correction Using Total Power Radiometry at the Submillimeter Array
Phase noise caused by an inhomogeneous, time-variable water vapor
distribution in our atmosphere reduces the angular resolution, visibility
amplitude and coherence time of millimeter and submillimeter wavelength
interferometers. We present early results from our total power radiometry phase
correction experiment carried out with the Submillimeter Array on Mauna Kea.
From accurate measurements of the atmospheric emission along the lines of
sight of two elements of the array, we estimated the differential atmospheric
electrical path between them. In one test, presented here, the phase correction
technique reduced the rms phase noise at 230 GHz from 72\degr to 27\degr
over a 20 minute period with a 2.5 second integration time. This corresponds to
a residual differential electrical path of 98 m, or 15 m of
precipitable water vapor, and raises the coherence in the 20 minute period from
0.45 to 0.9.Comment: Accepted for publication in the SMA Special Volume of the ApJ Letters
(9 pages of text, 3 figures
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