208 research outputs found
Dust emission from a parsec-scale structure in the Seyfert 1 nucleus of NGC 4151
We report mid-IR interferometric measurements with \sim 10 mas resolution,
which resolve the warm (T = 285 +25 / -50 K) thermal emission at the center of
NGC 4151. Using pairs of VLT 8.2 m telescopes with MIDI and by comparing the
data to a Gaussian model, we determined the diameter of the dust emission
region, albeit only along one position angle, to be 2.0 +/- 0.4 pc (FWHM). This
is the first size and temperature estimate for the nuclear warm dust
distribution in a Seyfert 1 galaxy. The parameters found are comparable to
those in Seyfert 2 galaxies, thus providing direct support for the unified
model. Using simple analytic temperature distributions, we find that the
mid-infrared emission is probably not the smooth continuation of the hot
nuclear source that is marginally resolved with K band interferometry. We also
detected weak excess emission around 10.5 micron in our shorter baseline
observation, possibly indicating that silicate emission is extended to the
parsec scale.Comment: 5 pages, 4 figures, accepted for publication in The Astrophysical
Journal Letter
Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey
The emission of warm dust dominates the mid-infrared spectra of active
galactic nuclei (AGN). Only interferometric observations provide the necessary
angular resolution to resolve the nuclear dust and to study its distribution
and properties. The investigation of dust in AGN cores is hence one of the main
science goals for the MID-infrared Interferometric instrument MIDI at the VLTI.
As the first step, the feasibility of AGN observations was verified and the
most promising sources for detailed studies were identified. This was carried
out in a "snapshot survey" with MIDI using Guaranteed Time Observations. In the
survey, observations were attempted for 13 of the brightest AGN in the
mid-infrared which are visible from Paranal. The results of the three
brightest, best studied sources have been published in separate papers. Here we
present the interferometric observations for the remaining 10, fainter AGN. For
8 of these, interferometric measurements could be carried out. Size estimates
or limits on the spatial extent of the AGN-heated dust were derived from the
interferometric data of 7 AGN. These indicate that the dust distributions are
compact, with sizes on the order of a few parsec. The derived sizes roughly
scale with the square root of the luminosity in the mid-infrared, s ~ sqrt(L),
with no clear distinction between type 1 and type 2 objects. This is in
agreement with a model of nearly optically thick dust structures heated to T ~
300 K. For three sources, the 10 micron feature due to silicates is tentatively
detected either in emission or in absorption. Based on the results for all AGN
studied with MIDI so far, we conclude that in the mid-infrared the differences
between individual galactic nuclei are greater than the generic differences
between type 1 and type 2 objects.Comment: 18 pages, 8 figures, updated to version published in A&A 502, 67-8
The use and predictive performance of the Peninsula Health Falls Risk Assessment Tool (PH-FRAT) in 25 residential aged care facilities : a retrospective cohort study using routinely collected data
Background: The Peninsula Health Falls Risk Assessment Tool (PH-FRAT) is a validated and widely applied tool in residential aged care facilities (RACFs) in Australia. However, research regarding its use and predictive performance is limited. This study aimed to determine the use and performance of PH-FRAT in predicting falls in RACF residents. Methods: A retrospective cohort study using routinely-collected data from 25 RACFs in metropolitan Sydney, Australia from Jul 2014-Dec 2019. A total of 5888 residents aged ≥65 years who were assessed at least once using the PH-FRAT were included in the study. The PH-FRAT risk score ranges from 5 to 20 with a score > 14 indicating fallers and ≤ 14 non-fallers. The predictive performance of PH-FRAT was determined using metrics including area under receiver operating characteristics curve (AUROC), sensitivity, specificity, sensitivityEvent Rate(ER) and specificityER. Results: A total of 27,696 falls were reported over 3,689,561 resident days (a crude incident rate of 7.5 falls /1000 resident days). A total of 38,931 PH-FRAT assessments were conducted with a median of 4 assessments per resident, a median of 43.8 days between assessments, and an overall median fall risk score of 14. Residents with multiple assessments had increased risk scores over time. The baseline PH-FRAT demonstrated a low AUROC of 0.57, sensitivity of 26.0% (sensitivityER 33.6%) and specificity of 88.8% (specificityER 82.0%). The follow-up PH-FRAT assessments increased sensitivityER values although the specificityER decreased. The performance of PH-FRAT improved using a lower risk score cut-off of 10 with AUROC of 0.61, sensitivity of 67.5% (sensitivityER 74.4%) and specificity of 55.2% (specificityER 45.6%). Conclusions: Although PH-FRAT is frequently used in RACFs, it demonstrated poor predictive performance raising concerns about its value. Introducing a lower PH-FRAT cut-off score of 10 marginally enhanced its predictive performance. Future research should focus on understanding the feasibility and accuracy of dynamic fall risk predictive tools, which may serve to better identify residents at risk of falls
Profiling complex word usage in the speech of English preschool children: frequency patterns and transparency characteristics
This corpus-based study provides a baseline of complex word usage patterns in the spontaneous speech of English preschool children to ascertain the characteristics of their derivative vocabulary before literacy development affects language skills. Frequencies of suffixed derivatives produced by (N=243) children aged 2-5 and their caregivers were extracted for 58 suffix variants, yielding 558 types from the former and 1,364 from the latter. Between the youngest and oldest groups, 11 suffix categories increased significantly in type frequency, compared with 22 in the caregiver dataset. All derivative types were classified for transparency of meaning and simplicity of form on a 5-point analysability scale. Around 59% of both the child and caregiver derivative vocabulary sets were classified as transparent regardless of age, suggesting that the potential analysability of the preschool child’s input remains surprisingly invariant over time. The study provides baseline data for future studies on the development of morphological awareness in English-speaking schoolchildren
Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
To test the dust torus model for active galactic nuclei directly, we study
the extent and morphology of the nuclear dust distribution in the Circinus
galaxy using high resolution interferometric observations in the mid-infrared
with the MIDI instrument at the Very Large Telescope Interferometer. We find
that the dust distribution in the nucleus of Circinus can be explained by two
components, a dense and warm disk-like component of 0.4 pc size and a slightly
cooler, geometrically thick torus component with a size of 2.0 pc. The disk
component is oriented perpendicular to the ionisation cone and outflow and
seems to show the silicate feature at 10 micron in emission. It coincides with
a nuclear maser disk in orientation and size. From the energy needed to heat
the dust, we infer a luminosity of the accretion disk corresponding to 20% of
the Eddington luminosity of the nuclear black hole. We find that the
interferometric data are inconsistent with a simple, smooth and axisymmetric
dust emission. The irregular behaviour of the visibilities and the shallow
decrease of the dust temperature with radius provide strong evidence for a
clumpy or filamentary dust structure. We see no evidence for dust reprocessing,
as the silicate absorption profile is consistent with that of standard galactic
dust. We argue that the collimation of the ionising radiation must originate in
the geometrically thick torus component. Our findings confirm the presence of a
geometrically thick, torus-like dust distribution in the nucleus of Circinus,
as required in unified schemes of Seyfert galaxies. Several aspects of our data
require that this torus is irregular, or "clumpy".Comment: 20 pages, 16 figures, accepted for publication by A&
What was Progressive in ‘Progressive Conservatism’?
In January 2009 David Cameron announced that the ‘underlying philosophy’ of his government would be progressive conservatism. Despite the ambiguity about this term, it was generally interpreted as a signal that Cameron was moving his party to the left.To some commentators, Cameron was allying with the progressive ‘one nation’ strand of conservative thought.To others, particularly in the media, he was drawing on the more immediate influence of Phillip Blond’s ‘Red Toryism’. However, the focus on the market (as opposed to state or community) found in both Cameron’s speech and subsequent policies sits uneasily with both of these interpretations. Cameron’s progressive conservatism has more in common with Thatcherism – an earlier conservative modernising project – than it does with centrist forms of conservative progressivism. Cameron’s progressive conservatism is progressive, but only in particular, less commonly used, ways – not as a rediscovery of social justice
Sub-millimeter to centimeter excess emission from the Magellanic Clouds. I. Global spectral energy distribution
In order to reconstruct the global SEDs of the Magellanic Clouds over eight
decades in spectral range, we combined literature flux densities representing
the entire LMC and SMC respectively, and complemented these with maps extracted
from the WMAP and COBE databases covering the missing the 23--90 GHz (13--3.2
mm) and the poorly sampled 1.25--250 THz (240--1.25 micron). We have discovered
a pronounced excess of emission from both Magellanic Clouds, but especially the
SMC, at millimeter and sub-millimeter wavelengths. We also determined accurate
thermal radio fluxes and very low global extinctions for both LMC and SMC.
Possible explanations are briefly considered but as long as the nature of the
excess emission is unknown, the total dust masses and gas-to-dust ratios of the
Magellanic Clouds cannot reliably be determined.Comment: Accepted for publication by A&
VLTI/AMBER observations of the Seyfert nucleus of NGC 3783
Context. The putative tori surrounding the accretion disks of active galactic
nuclei (AGNs) play a fundamental role in the unification scheme of AGNs.
Infrared long-baseline interferometry allows us to study the inner dust
distribution in AGNs with unprecedented spatial resolution over a wide infrared
wavelength range.
Aims. Near- and mid-infrared interferometry is used to investigate the
milli-arcsecond-scale dust distribution in the type 1.5 Seyfert nucleus of NGC
3783.
Methods. We observed NGC 3783 with the VLTI/AMBER instrument in the K-band
and compared our observations with models.
Results. From the K-band observations, we derive a ring-fit torus radius of
0.74 +/- 0.23 mas or 0.16 +/- 0.05 pc. We compare this size with infrared
interferometric observations of other AGNs and UV/optical-infrared
reverberation measurements. For the interpretation of our observations, we
simultaneously model our near- and mid-infrared visibilities and the SED with a
temperature/density-gradient model including an additional inner hot 1400 K
ring component
Co-designing a dashboard of predictive analytics and decision support to drive care quality and client outcomes in aged care: a mixed-method study protocol
IntroductionThere is a clear need for improved care quality and quality monitoring in aged care. Aged care providers collect an abundance of data, yet rarely are these data integrated and transformed in real-time into actionable information to support evidence-based care, nor are they shared with older people and informal caregivers. This protocol describes the co-design and testing of a dashboard in residential aged care facilities (nursing or care homes) and community-based aged care settings (formal care provided at home or in the community). The dashboard will comprise integrated data to provide an 'at-a-glance' overview of aged care clients, indicators to identify clients at risk of fall-related hospitalisations and poor quality of life, and evidence-based decision support to minimise these risks. Longer term plans for dashboard implementation and evaluation are also outlined.MethodsThis mixed-method study will involve (1) co-designing dashboard features with aged care staff, clients, informal caregivers and general practitioners (GPs), (2) integrating aged care data silos and developing risk models, and (3) testing dashboard prototypes with users. The dashboard features will be informed by direct observations of routine work, interviews, focus groups and co-design groups with users, and a community forum. Multivariable discrete time survival models will be used to develop risk indicators, using predictors from linked historical aged care and hospital data. Dashboard prototype testing will comprise interviews, focus groups and walk-through scenarios using a think-aloud approach with staff members, clients and informal caregivers, and a GP workshop.Ethics and disseminationThis study has received ethical approval from the New South Wales (NSW) Population & Health Services Research Ethics Committee and Macquarie University's Human Research Ethics Committee. The research findings will be presented to the aged care provider who will share results with staff members, clients, residents and informal caregivers. Findings will be disseminated as peer-reviewed journal articles, policy briefs and conference presentations
Urban interventionism as a challenge to aesthetic order::Towards an aesthetic criminology
This article is concerned with ideas of urban order and considers the scope for playing with people’s expectations of order. In particular, drawing on criminological, philosophical and urban studies literatures, the article explores the notion of aesthetic order. The power to dictate aesthetic order is highlighted. The example of urban interventionism is used to consider those that challenge an approved aesthetic order. Here the article draws on cultural criminology and visual criminology, with illustrations coming from research in Toronto, Canada. Influenced by Alison Young’s (2014a) conceptualisation of ‘cities within the city’, the article considers how different people using the same space have different or overlapping ways of understanding aesthetic order. Of relevance to criminology, it is contended that people or things that contravene an approved aesthetic order may face banishment and criminalisation. It is concluded that respect for such difference is required. An aesthetic criminology is suggested
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