6,900 research outputs found
Framework for software architecture visualization assessment.
In order to assess software architecture visualisation strategies, we qualitatively characterize then construct an assessment framework with 7 key areas and 31 features. The framework is used for evaluation and comparison of various strategies from multiple stakeholder perspectives. Six existing software architecture visualisation tools and a seventh research tool were evaluated. All
tools exhibited shortcomings when evaluated in the framework
Influence of anneal atmosphere on ZnO-nanorod photoluminescent and morphological properties with self-powered photodetector performance
OA Monitor ExerciseEPSR
Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Design Requirements Document (DRD)
A description and the design requirements for the 200 MWe (nominal) net output MHD Engineering Test Facility (ETF) Conceptual Design, are presented. Performance requirements for the plant are identified and process conditions are indicated at interface stations between the major systems comprising the plant. Also included are the description, functions, interfaces and requirements for each of these major systems. The lastest information (1980-1981) from the MHD technology program are integrated with elements of a conventional steam electric power generating plant
Hydrogen Two-Photon Continuum Emission from the Horseshoe Filament in NGC 1275
Far ultraviolet emission has been detected from a knot of Halpha emission in
the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected
relative to the brightness of the Halpha line in the same spatial region is
very close to that expected from Hydrogen two-photon continuum emission in the
particle heating model of Ferland et al. (2009) if reddening internal to the
filaments is taken into account. We find no need to invoke other sources of far
ultraviolet emission such as hot stars or emission lines from CIV in
intermediate temperature gas to explain these data.Comment: 9 pages, 8 figures. Accepted for publication in MNRA
The host galaxy of the z=2.4 radio-loud AGN MRC 0406-244 as seen by HST
We present multicolour Hubble Space Telescope images of the powerful z=2.4
radio galaxy MRC 0406-244 and model its complex morphology with several
components including a host galaxy, a point source, and extended nebular and
continuum emission. We suggest that the main progenitor of this radio galaxy
was a normal, albeit massive (M ~10^{11} solar masses), star-forming galaxy.
The optical stellar disc of the host galaxy is smooth and well described by a
S\'ersic profile, which argues against a recent major merger, however there is
also a point-source component which may be the remnant of a minor merger. The
half-light radius of the optical disc is constrained to lie in the range 3.5 to
8.2kpc, which is of similar size to coeval star forming galaxies.
Biconical shells of nebular emission and UV-bright continuum extend out from
the host galaxy along the radio jet axis, which is also the minor axis of the
host galaxy. The origin of the continuum emission is uncertain, but it is most
likely to be young stars or dust-scattered light from the AGN, and it is
possible that stars are forming from this material at a rate of
200^{+1420}_{-110} solar masses per year.Comment: Accepted for publication in MNRA
Galaxy protocluster candidates around z ~ 2.4 radio galaxies
We study the environments of 6 radio galaxies at 2.2 < z < 2.6 using
wide-field near-infrared images. We use colour cuts to identify galaxies in
this redshift range, and find that three of the radio galaxies are surrounded
by significant surface overdensities of such galaxies. The excess galaxies that
comprise these overdensities are strongly clustered, suggesting they are
physically associated. The colour distribution of the galaxies responsible for
the overdensity are consistent with those of galaxies that lie within a narrow
redshift range at z ~ 2.4. Thus the excess galaxies are consistent with being
companions of the radio galaxies. The overdensities have estimated masses in
excess of 10^14 solar masses, and are dense enough to collapse into virizalised
structures by the present day: these structures may evolve into groups or
clusters of galaxies. A flux-limited sample of protocluster galaxies with K <
20.6 mag is derived by statistically subtracting the fore- and background
galaxies. The colour distribution of the protocluster galaxies is bimodal,
consisting of a dominant blue sequence, comprising 77 +/- 10% of the galaxies,
and a poorly populated red sequence. The blue protocluster galaxies have
similar colours to local star-forming irregular galaxies (U -V ~ 0.6),
suggesting most protocluster galaxies are still forming stars at the observed
epoch. The blue colours and lack of a dominant protocluster red sequence
implies that these cluster galaxies form the bulk of their stars at z < 3.Comment: Accepted for publication in MNRA
A SINFONI view of flies in the Spiderweb: a galaxy cluster in the making
The environment of the high-z radio galaxy PKS 1138-262 at z~2.2 is a prime
example of a forming galaxy cluster. We use deep SINFONI data to perform a
detailed study of the kinematics of the galaxies within 60 kpc of the radio
core and we link this to the kinematics of the protocluster on the megaparsec
scale. Identification of optical emission lines shows that 11 galaxies are at
the redshift of the protocluster. The density of line emitters is more than an
order of magnitude higher in the core of the protocluster than the larger scale
environment. This implies a matter overdensity in the core of delta_m~70 which
is similar to the outskirts of local galaxy clusters. The velocity distribution
of the confirmed satellite galaxies shows a broad, double-peaked velocity
structure with sigma=1360+/-206 km/s. A similar broad, double-peaked
distribution was found in a previous study targeting the large scale
protocluster structure, indicating that a common process is acting on both
small and large scales. Including all spectroscopically confirmed protocluster
galaxies, a velocity dispersion of 1013+/-87 km/s is found. We show that the
protocluster has likely decoupled from the Hubble flow and is a dynamically
evolved structure. Comparison to the Millenium simulation indicates that the
protocluster velocity distribution is consistent with that of the most massive
haloes at z~2, but we rule out that the protocluster is a fully virialized
structure based on dynamical arguments and its X-ray luminosity. Comparison to
merging haloes in the Millennium simulation shows that the structure as
observed in and around the Spiderweb galaxy is best interpreted as being the
result of a merger between two massive haloes. We propose that this merger can
result in an increase in star formation and AGN activity in the protocluster
core and is possibly an important stage in the evolution of massive cD
galaxies.Comment: 12 pages, 7 figures. Accepted for publication in MNRA
Field Experiments to Help Optimise Nitrogen Fixation by Legumes on Organic Farms
During an organic rotation, the aim is to increase the nitrogen (N) content of the soil (and hence build up soil fertility) by recycling crop residues, applying manures/composts and from N fixed by legumes. IGER, with ADAS, Duchy College Cornwall and Abacus Organic Associates are developing improved guidance for organic farmers in the use of fertility-building crops. The main questions are: how to maximise N fixation and how to make the most efficient use of the fixed N? Available soil mineral N, which is generally thought to reduce N fixation, will be increased by manure applications, cutting/mulching and grazing. We describe an experiment to establish the extent to which animal and green manures can adversely affect N fixation. The results from the first year (2003) were reported recently (Hatch et al., 2004). Here we summarise the findings from 2 years’ results (2003-4) to show the changes that occurred after the legume crop became fully established
Citizenship Documentation Requirement for Medical Eligibility: Effects on Oregon Children
BACKGROUND AND OBJECTIVES: The Deficit Reduction Act (DRA) of 2005 mandated Medicaid beneficiaries to document citizenship. Using a prospective cohort (n=104,375), we aimed to (1) determine characteristics of affected children, (2) describe effects on health insurance coverage and access to needed health care, and (3) model the causal relationship between this new policy, known determinants of health care access, and receipt of needed health care. METHODS: We identified a stratified random sample of children shortly after the DRA was implemented and used state records and surveys to compare three groups: children denied Medicaid for inability to document citizenship, children denied for other reasons, and children accepted for coverage. To combat survey nonresponse, we used Medicaid records to identify differences between responders and nonrespondents and created survey weights to account for these differences. Weighted simple and multivariable logistic regression described the complete, originally identified population. RESULTS: Children denied Medicaid for inability to document citizenship were likely to be US citizens, were medically and socially more vulnerable than their peers, and went on to have gaps in health insurance coverage and unmet health care needs. The DRA led to persistent loss of insurance coverage, which decreased access to needed health care. Having a usual source of care was an effect modifier in this relationship. CONCLUSIONS: Our findings demonstrate the negative consequences of the DRA and support the use of automated methods of citizenship verification allowed under the Patient Protection and Affordable Care Act
The extended H-alpha emitting filaments surrounding NGC4696, the central galaxy of the Centaurus cluster
We present images of NGC4696, the central galaxy in the Centaurus cluster,
showing the large extent of cool filaments which are bright in H-alpha line
emission. These filaments share the detailed structure of both the central dust
lane and the inner regions of the arc-like plumes seen in soft X-ray emission.
The X-ray gas is at its coolest, and most absorbed in this same region. The
smoothness of the features implies that the local environment is not strongly
turbulent. We suggest that these filaments are either shaped by confinement due
to a strong magnetic field, or by bulk flows within the intracluster medium. We
propose that like similar filamentary systems in the core of clusters, these
cooler components have been drawn out of the central galaxy behind buoyant gas
bubbles from previous episodes of radio activity. We find a spur of
low-frequency radio emission leading to a region of low X-ray pressure within
the intracluster medium supporting this interpretation.Comment: 7 pages, including 5 composite figures; accepted for publication in
MNRAS. Copy of paper with best quality figures available at
http://www-xray.ast.cam.ac.uk/~csc/centaurus.htm
- …