4,088 research outputs found
Asteroids Observed by The Sloan Digital Sky Survey
We announce the first public release of the SDSS Moving Object Catalog, with
SDSS observations for 58,117 asteroids. The catalog lists astrometric and
photometric data for moving objects observed prior to Dec 15, 2001, and also
includes orbital elements for 10,592 previously known objects. We analyze the
correlation between the orbital parameters and optical colors for the known
objects, and confirm that asteroid dynamical families, defined as clusters in
orbital parameter space, also strongly segregate in color space. Their
distinctive optical colors indicate that the variations in chemical composition
within a family are much smaller than the compositional differences between
families, and strongly support earlier suggestions that asteroids belonging to
a particular family have a common origin.Comment: 6 pages, 1 color figure, to be presented at "Astronomical Telescopes
& Instrumentation", SPIE 200
Slow Hopping and Spin Dephasing of Coulombically Bound Polaron Pairs in an Organic Semiconductor at Room Temperature
Polaron pairs are intermediate electronic states that are integral to the optoelectronic conversion process in organic semiconductors. Here, we report on electrically detected spin echoes arising from direct quantum control of polaron pair spins in an organic light-emitting diode at room temperature. This approach reveals phase coherence on a microsecond time scale, and offers a direct way to probe charge recombination and dissociation processes in organic devices, revealing temperature-independent intermolecular carrier hopping on slow time scales. In addition, the long spin phase coherence time at room temperature is of potential interest for developing quantum-enhanced sensors and information processing systems which operate at room temperature
Promoting medical student engagement with antimicrobial stewardship through involvement in undergraduate research
The National Health Service recognises the importance of research, teaching, and training to the future success of the organisation and medical students are expected to qualify with the necessary clinical, professional, and academic skills to support this. There is a wide variation in the level of cross-specialty engagement with Antimicrobial Stewardship (AMS) & Antimicrobial resistance (AMR) research at UK and international state-of-the-art conferences, with a heterogeneous level of importance also attributed amongst undergraduate and postgraduate training pathways across clinical medicine. It therefore seems apparent that the AMS-AMR agenda needs to be promoted from within specialties, rather than being âpushedâ on them as an external agenda, to promote broad ownership and capacity within all clinical specialties that use antimicrobials. This must start early during undergraduate medical training. We investigated whether the use of an online platform designed to facilitate medical student research projects could be utilised to promote undergraduate engagement with AMSAMR at Imperial College School of Medicine between July 2015 and 2016. During this period 12 applicants were appointed to 11 of the 13 advertised projects. So far, students undertaking these projects have achieved: 1 peer-reviewed publication, 3 national oral presentations, 1 national prize, 1 international poster presentation, 3 national poster presentations, and 2 further manuscripts are currently under peer-review. Furthermore, despite the studentsâ broad career interests there has been a high retention rate with students requesting involvement in further AMS-AMR related activities. Further longitudinal assessment of this tool for promoting undergraduate engagement with AMS-AMR research is now being explored
A Survey of z~6 Quasars in the SDSS Deep Stripe. II. Discovery of Six Quasars at z_{AB}>21
We present the discovery of six new quasars at z~6 selected from the Sloan
Digital Sky Survey (SDSS) southern survey, a deep imaging survey obtained by
repeatedly scanning a stripe along the celestial equator. The six quasars are
about two magnitudes fainter than the luminous z~6 quasars found in the SDSS
main survey and one magnitude fainter than the quasars reported in Paper I
(Jiang et al. 2008). Four of them comprise a complete flux-limited sample at
21<z_AB<21.8 over an effective area of 195 deg^2. The other two quasars are
fainter than z_AB=22 and are not part of the complete sample. The quasar
luminosity function at z~6 is well described as a single power law
\Phi(L_{1450}) \propto L_{1450}^{\beta} over the luminosity range
-28<M_{1450}<-25. The best-fitting slope \beta varies from -2.6 to -3.1,
depending on the quasar samples used, with a statistical error of 0.3-0.4.
About 40% of the quasars discovered in the SDSS southern survey have very
narrow Lya emission lines, which may indicate small black hole masses and high
Eddington luminosity ratios, and therefore short black hole growth time scales
for these faint quasars at early epochs.Comment: Accepted for publication in A
Evotype: Towards the Evolution of Type Stencils
Typefaces are an essential resource employed by graphic designers. The
increasing demand for innovative type design work increases the need for good
technological means to assist the designer in the creation of a typeface. We
present an evolutionary computation approach for the generation of type
stencils to draw coherent glyphs for different characters. The proposed system
employs a Genetic Algorithm to evolve populations of type stencils. The
evaluation of each candidate stencil uses a hill climbing algorithm to search
the best configurations to draw the target glyphs. We study the interplay
between legibility, coherence and expressiveness, and show how our framework
can be used in practice.Comment: EvoMUSART 2018 Best pape
A 3D full-field study of cracks in a nuclear graphite under mode I and mode II cyclic dwell loading conditions
Threeâdimensional (3D) fullâfield deformation around crack tips in a nuclear graphite has been studied under mode I and mode II cyclic dwell loading conditions using digital volume correlation (DVC) and integrated finite element (FE) analysis. A cracked Brazilian disk specimen of Gilsocarbon graphite was tested at selected loading angles to achieve mode I and mode II cyclic dwell loading conditions. Integrated FE analysis was carried out with the 3D displacement fields measured by DVC injected into the FE model, from which the crack driving force Jâintegral was obtained using a damaged plasticity material model. The evolution of nearâtip strains and the Jâintegral during the cyclic dwell loading was examined. Under cyclic dwell, residual strain accumulation was observed for the first time. The results shed some light on the effect of dwell time on the 3D crack deformation and crack driving force in Gilsocarbon under cyclic mode I and II loading conditions
Changing emotional engagement with running through communal self-tracking: The implications of âteleoaffective shapingâ for public health,
Rethinking place and the social work office in the delivery of children's social work services
Limited attention has been given to the concept of place in social work research and practice. This paper draws on the national evaluation of social work practices (SWPs) in England undertaken between 2009 and 2012. SWPs were pilot organisations providing independent social work services for children in out-of-home care in five sites. One factor distinguishing some of these pilots was their attention to place. The evaluation employed a mixed methods approach and we use data from interviews with 121 children and young people in out-of-home care, 19 birth parents and 31 interviews with SWP staff which explored their views and experiences of the SWP offices. Children and young people
were alert to the stigma which could attach to social work premises and appreciated offices which were planned and furnished to appear less institutional and more ânormalâ. Daily interactions with staff which conveyed a sense of recognition and value to service users also contributed to a view of some SWP offices as accessible and welcoming places. Both children and parents appreciated offices that provided fun activities that positioned them as active rather than passive. Staff valued opportunities for influencing planning decisions about offices and place
was seen to confer a value on them as well as on service users. However, not all the SWPs were able to achieve these aspects of place, and engaging children and families in place was less likely when the service user population was widely dispersed. Recognising the importance of place and how place is constructed through relationships between people as well as through the physical environment appeared to be key to creating offices that combated the stigma attached to out-of-home care.
Those leading and managing childrenâs services should explore ways of involving local communities in planning social work offices and turn attention to making these offices accessible, welcoming, places
A Survey of z ~ 6 Quasars in the Sloan Digital Sky Survey Deep Stripe. II. Discovery of Six Quasars at z AB>21
We present the discovery of six new quasars at z ~ 6 selected from the Sloan Digital Sky Survey (SDSS) southern survey, a deep imaging survey obtained by repeatedly scanning a stripe along the celestial equator. The six quasars are about 2 mag fainter than the luminous z ~ 6 quasars found in the SDSS main survey and 1 mag fainter than the quasars reported in Paper I. Four of them comprise a complete flux-limited sample at 21 < z_(AB) < 21.8 over an effective area of 195 deg^2. The other two quasars are fainter than z_(AB) = 22 and are not part of the complete sample. The quasar luminosity function at z ~ 6 is well described as a single power law Ί(L_(1450))α L^ÎČ_(1450) over the luminosity range â28 < M_(1450) < â25. The best-fitting slope ÎČ varies from â2.6 to â3.1, depending on the quasar samples used, with a statistical error of 0.3-0.4. About 40% of the quasars discovered in the SDSS southern survey have very narrow Lyα emission lines, which may indicate small black hole masses and high Eddington luminosity ratios, and therefore short black hole growth timescales for these faint quasars at early epochs
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