317 research outputs found
Discovery of planetary nebulae using predictive mid-infrared diagnostics
We demonstrate a newly developed mid-infrared planetary nebula (PN) selection
technique. It is designed to enable efficient searches for obscured, previously
unknown, PN candidates present in the photometric source catalogues of Galactic
plane MIR sky surveys. Such selection is now possible via new, sensitive,
high-to-medium resolution, MIR satellite surveys such as those from the Spitzer
Space Telescope and the all-sky Wide-Field Infrared Survey Explorer (WISE)
satellite missions. MIR selection is based on how different colour-colour
planes isolate zones (sometimes overlapping) that are predominately occupied by
different astrophysical object types. These techniques depend on the
reliability of the available MIR source photometry. In this pilot study we
concentrate on MIR point source detections and show that it is dangerous to
take the MIR GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire)
photometry from Spitzer for each candidate at face value without examining the
actual MIR image data. About half of our selected sources are spurious
detections due to the applied source detection algorithms being affected by
complex MIR backgrounds and the de-blending of diffraction spikes around bright
MIR point sources into point sources themselves. Nevertheless, once this
additional visual diagnostic checking is performed, valuable MIR selected PN
candidates are uncovered. Four turned out to have faint, compact, optical
counterparts in our H-alpha survey data missed in previous optical searches. We
confirm all of these as true PNe via our follow-up optical spectroscopy. This
lends weight to the veracity of our MIR technique. It demonstrates sufficient
robustness that high-confidence samples of new Galactic PN candidates can be
extracted from these MIR surveys without confirmatory optical spectroscopy and
imaging. This is problematic or impossible when the extinction is large.Comment: 14 pages, 7 figures, 7 tables; accepted for publication in MNRA
Detailed Studies of IPHAS sources. II. Sab 19, a true planetary nebula and its mimic crossing the Perseus Arm
The INT Photometric H Survey (IPHAS) has provided us with a number of
new-emission line sources, among which planetary nebulae (PNe) constitute an
important fraction. Here we present a detailed analysis of the IPHAS nebula
Sab\,19 (IPHASX\,J055242.8+262116) based on radio, infrared, and optical images
and intermediate- and high-dispersion longslit spectra. Sab\,19 consists of a
roundish 0.10 pc in radius double-shell nebula surrounded by a much larger 2.8
pc in radius external shell with a prominent H-shaped filament. We confirm the
nature of the main nebula as a PN whose sub-solar N/O ratio abundances, low
ionized mass, peculiar radial velocity, and low-mass central star allow us to
catalog it as a type III PN. Apparently, the progenitor star of Sab\,19 became
a PN when crossing the Perseus Arm during a brief visit of a few Myr. The
higher N/O ratio and velocity shift 40 \kms\ of the external shell with
respect to the main nebula and its large ionized mass suggest that it is not
truly associated with Sab\,19, but it is rather dominated by a Str\"omgren zone
in the interstellar medium ionized by the PN central star.Comment: 12 pages, 8 figures, accepted for publication in MNRA
Smallest Number of Sensors for k-Covering
This paper presents some theoretical results on the smaller number Nk(a, b) of sensors to achieve k coverage for the rectangular area [0, a] × [0, b]. The first properties show the numbers Nk(a, b) are sub-additive and increasing on each variable. Based on these results, some lower and upper bounds for Nk(a, b) are introduced. The main result of the article proves that the minimal density of sensors to achieve k-coverage is (k) ≤ k/2 improving a previous result of Ammari and Das [2]. Finally, the numbers N1(a, b) are tabled for some small values of a, b
Further Studies of the Association of Planetary Nebula BMP J16135406 with Galactic Open Cluster NGC 6067
Planetary Nebulae (PNe) that are physical members of Galactic open clusters are powerful probes that allow precise determination of their distance and crucially their initial mass on the main sequence. Here, we revisit the physical association of the PN BMP J1613–5406 with the open cluster NGC 6067 and present our preliminary results based on our new ESO/VLT FORS2 data. Our PN spectral data permit the calculation of a precise radial velocity and reddening to the PN that shows a tight consistency with the literature corresponding cluster parameters including importantly the radial velocity. Our measurements, combined with the agreement between the distances of the two objects and the fact that the PN is located well within the cluster boundaries, confirm that the PN is physically associated with the cluster. The cluster has a turn-off mass of around 5 solar masses that indicates a PN initial mass of around 5.6 solar masses. This is closer to the theoretical lower limit of core-collapse supernova formation than has ever been previously observed, providing a unique opportunity for further stellar and Galactic chemical evolution studies using this system
The effects of leaflet material properties on the simulated function of regurgitant mitral valves
Advances in three-dimensional imaging provide the ability to construct and
analyze finite element (FE) models to evaluate the biomechanical behavior and
function of atrioventricular valves. However, while obtaining patient-specific
valve geometry is now possible, non-invasive measurement of patient-specific
leaflet material properties remains nearly impossible. Both valve geometry and
tissue properties play a significant role in governing valve dynamics, leading
to the central question of whether clinically relevant insights can be attained
from FE analysis of atrioventricular valves without precise knowledge of tissue
properties. As such we investigated 1) the influence of tissue extensibility
and 2) the effects of constitutive model parameters and leaflet thickness on
simulated valve function and mechanics. We compared metrics of valve function
(e.g., leaflet coaptation and regurgitant orifice area) and mechanics (e.g.,
stress and strain) across one normal and three regurgitant mitral valve (MV)
models with common mechanisms of regurgitation (annular dilation, leaflet
prolapse, leaflet tethering) of both moderate and severe degree. We developed a
novel fully-automated approach to accurately quantify regurgitant orifice areas
of complex valve geometries. We found that the relative ordering of the
mechanical and functional metrics was maintained across a group of valves using
material properties up to 15% softer than the representative adult mitral
constitutive model. Our findings suggest that FE simulations can be used to
qualitatively compare how differences and alterations in valve structure affect
relative atrioventricular valve function even in populations where material
properties are not precisely known
Determining the need for a breast cancer awareness educational intervention for women with mild/moderate levels of intellectual disability: A qualitative descriptive study
OBJECTIVE: Following a review of the existing body of literature, this study aimed to explore the need for a breast cancer awareness intervention specifically targeted at women with mild/moderate levels of intellectual disability (ID) and provide perspectives on the preferred processes and content underpinning an intervention. METHODS: A qualitative, descriptive design using semi‐structured, individual (n = 5) and focus group (n = 5) interviews were used to engage with a non‐probability, purposive sample of key stakeholders (n = 25) including women with mild/moderate levels of ID, caregivers and healthcare professionals. Data were analysed using qualitative content analysis. RESULTS: Findings highlighted that an educational intervention should focus on breast awareness as opposed to breast cancer awareness. Additionally, findings identified that a combined breast awareness and healthy living intervention could be effective. However, the intervention needs to have a multimodal, hands‐on, person‐centred approach to learning which is underpinned by theory. Furthermore, integrating the caregivers and healthcare professionals into the intervention is recommended. CONCLUSION: Findings from this study provide a foundation for developing and implementing a theoretically underpinned, multimodal, breast awareness and healthy living educational intervention for women with mild/moderate levels of ID
Defining breast cancer awareness and identifying barriers to breast cancer awareness for women with an intellectual disability: A review of the literature
Introduction: Incidence rates for developing breast cancer are similar for women regardless of intellectual ability. However, women with an intellectual disability present with advanced breast cancers, which often have a poor prognosis. Method: A structured narrative review of the literature was performed to explore the concepts of breast awareness and breast cancer awareness and subsequently, identify barriers to breast cancer awareness encountered by women with an intellectual disability. Results: A total of 22 studies involving people with varying levels of intellectual disability informed this review. The barriers to breast cancer awareness encountered by women with an intellectual disability include: lack of their understanding, the role of the carer and literacy issues. Conclusion: Identifying the barriers to breast cancer awareness for women with an intellectual disability will help to facilitate breast cancer awareness which has the potential to result in better long-term outcomes through an early diagnosis of breast cancer
IGAPS: the merged IPHAS and UVEX optical surveys of the northern Galactic plane
The INT Galactic Plane Survey (IGAPS) is the merger of the optical photometric surveys, IPHAS and UVEX, based on data from the Isaac Newton Telescope (INT) obtained between 2003 and 2018. Here, we present the IGAPS point source catalogue. It contains 295.4 million rows providing photometry in the filters, i, r, narrow-band Ha, g, and URGO. The IGAPS footprint fills the Galactic coordinate range, |b| 5s confidence).Peer ReviewedPostprint (published version
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