544 research outputs found
Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability III: The Central Star of Abell 65
A growing number of close binary stars are being discovered among central
stars of planetary nebulae. Recent and ongoing surveys are finding new systems
and contributing to our knowledge of the evolution of close binary systems. The
push to find more systems was largely based on early discoveries which
suggested that 10 to 15% of all central stars are close binaries. One goal of
this series of papers is confirmation and classification of these systems as
close binaries and determination of binary system parameters. Here we provide
time-resolved multi-wavelength photometry of the central star of Abell 65 as
well as further analysis of the nebula and discussion of possible
binary--nebula connections. Our results for Abell 65 confirm recent work
showing that it has a close, cool binary companion, though several of our model
parameters disagree with the recently published values. With our longer time
baseline of photometric observations from 1989--2009 we also provide a more
precise orbital period of 1.0037577 days.Comment: Accepted for publication in the Astronomical Journa
Expression of Retroviral Transduced Human CD18 in Murine Cells: An In Vitro Model of Gene Therapy for Leukocyte Adhesion Deficiency
Overview summary In developing human gene therapy clinical protocols, it is helpful to have an animal model that mimics the human disease to be treated. A natural animal model for leukocyte adhesion deficiency (LAD) does not exist. Krauss et al. have developed a clever strategy for producing a mouse model for LAD gene therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63397/1/hum.1991.2.3-221.pd
Views of Caregivers on the Ethics of Assistive Technology used for Home Surveillance of People Living with Dementia
Estimating the burden of minor ailment consultations in general practices and emergency departments through retrospective review of routine data in North East Scotland
Minor ailment attendances in general practices and emergency departments (EDs) place significant burden on health care resources
Comparison of Construction Costs for Vegetated Treatment Systems in the Midwest
Vegetated treatment systems (VTSs) provide an alternative to containment basin systems for beef feedlot runoff control. Beef producers in the Midwestern United States have shown an increasing interest in using VTSs as a perceived lower cost option to containment basin systems. This paper reports the actual construction costs associated with 21 VTSs (eight on permitted Concentrated Animal Feeding Operations (CAFOs) and 13 on non permitted Animal Feeding Operations (AFOs)) located within Iowa, Minnesota, South Dakota, and Nebraska. The VTS construction costs are reported on a per head basis in 2009 adjusted dollars for each system. Cost comparisons are presented between CAFO and AFO facilities, by location and by system type. Additionally, estimated construction cost comparisons between open feedlots with VTS systems, open feedlots with containment basins, monoslope barns and hoop structure beef production systems are provided. Results from the cost comparison indicate that monoslope barns with concrete floors are the highest cost at 395 per head. Vegetated Treatment Systems designed for CAFO facilities (129 per head avg.) The same results indicated that an AFO VTS (195 per head). The data indicated that the least expensive VTS for an AFO is a sloped or sloped and level VTA (68 per head avg.) and a sprinkler VTS ($87 per head avg.)
Wild or Domestic? Biometric Variation in the Cat Felis silvestris Schreber
Investigation of modern biometric data indicates that it may be possible to distinguish wildcats from house cats in many instances. Applying the log-ratio (log-difference) technique to archaeological samples from medieval northern Europe, and to mixed samples of wildcats and house cats, shows that the differentiation may not always be clear, and the possibility that some samples include hybrids is discussed. The technique is applied to samples from the Orkney Islands to demonstrate that single wildcat specimens can be identified in small samples. Copyright (C) 2007 John Wiley & Sons, Ltd
A Spitzer/IRS Spectrum of the 2008 Luminous Transient in NGC 300: Connection to Proto-Planetary Nebulae
We present a Spitzer/IRS low-resolution mid-infrared spectrum (5-14 micron)
of the luminous transient discovered in the nearby galaxy NGC 300 in May 2008.
The spectrum, obtained three months after discovery, shows that the transient
is very luminous in the mid-IR. Furthermore, the spectrum shows strong, broad
emission features at 8 and 12 micron that are observed in Galactic carbon-rich
proto-planetary nebulae. Combining these data with published optical and
near-IR photometry obtained at the same epoch, we find that the mid-IR excess
traced by the Spitzer spectrum accounts for ~20% of the total energy output.
This component can be well explained by emission from ~3x10^-4 Msun of
pre-existing progenitor dust at temperature ~400 K. The spectral energy
distribution of the transient also shows a near-IR excess that can be explained
by emission from newly-formed dust in the ejecta. Alternatively, both the
near-IR and mid-IR excesses can together be explained by a single pre-existing
geometrically thick dust shell. In light of the new observations obtained with
Spitzer, we revisit the analysis of the optical spectra and kinematics, which
were compared to the massive yellow-hypergiant IRC+10420 in previous studies.
We show that proto-planetary nebulae share many properties with the NGC 300
transient and SN 2008S. We conclude that even though the explosion of a massive
star (> 10 Msun) cannot be ruled out, an explosive event on a massive (6-10
Msun) carbon-rich AGB/super-AGB or post-AGB star is consistent with all
observations of the transients and their progenitors presented thus far.Comment: 9 pages, 5 figures, 3 tables; references update
A qualitative inquiry into implementing an electronic health record system (SmartCare) for prevention of mother-to-child transmission data in Zambia: a retrospective study.
OBJECTIVE: This study aimed to investigate the challenges in implementing a Zambian electronic health records (EHR) system labelled 'SmartCare' from diverse stakeholder perspectives in order to improve prevention of mother-to-child transmission (PMTCT) data collection so that SmartCare can be used for clinic performance strengthening and programme monitoring. DESIGN: This is a qualitative retrospective study. SETTING AND PARTICIPANTS: SmartCare is a Zambian Ministry of Health (MoH)-led project funded by the US Centre for Disease Control and Prevention. Data were collected using in-depth interviews, observations and focus group discussions (FGDs) between September and November 2016. Seventeen in-depth interviews were held with a range of key informants from the MoH and local and international organisations implementing SmartCare. Four data entry observations and three FGDs with 22 pregnant and lactating women seeking PMTCT services were conducted. Data were analysed using a thematic content approach. RESULTS: The SmartCare system has evolved from various patient tracking systems into a multifunctional system. There is a burden of information required so that sometimes not all is collected and entered into the database, resulting in poor data quality. Funding challenges impede data collection due to manpower constraints and shortages of supplies. Challenges associated with data collection depend on whether a paper-based or computer-based system is used. There is no uniformity in the data quality verification and submission strategies employed by various IPs. There is little feedback from the EHR system at health facility level, which has led to disengagement as stakeholders do not see the importance of the system. CONCLUSION: SmartCare has structural challenges which can be traced from its development. Funding gaps have resulted in staffing and data collection disparities within IPs. The lack of feedback from the system has also led to complacency at the operational level, which has resulted in poor data quality in later years
Census of Self-Obscured Massive Stars in Nearby Galaxies with Spitzer: Implications for Understanding the Progenitors of SN 2008S-Like Transients
A new link in the causal mapping between massive stars and potentially fatal
explosive transients opened with the 2008 discovery of the dust-obscured
progenitors of the luminous outbursts in NGC 6946 and NGC 300. Here we carry
out a systematic mid-IR photometric search for massive, luminous, self-obscured
stars in four nearby galaxies: M33, NGC 300, M81, and NGC 6946. For detection,
we use only the 3.6 micron and 4.5 micron IRAC bands, as these can still be
used for multi-epoch Spitzer surveys of nearby galaxies (=<10 Mpc). We combine
familiar PSF and aperture-photometry with an innovative application of image
subtraction to catalog the self-obscured massive stars in these galaxies. In
particular, we verify that stars analogous to the progenitors of the NGC 6946
(SN 2008S) and NGC 300 transients are truly rare in all four galaxies: their
number may be as low as ~1 per galaxy at any given moment. This result
empirically supports the idea that the dust-enshrouded phase is a very
short-lived phenomenon in the lives of many massive stars and that these
objects constitute a natural extension of the AGB sequence. We also provide
mid-IR catalogs of sources in NGC 300, M81, and NGC 6946.Comment: 21 pages, 15 figures, 11 tables. Accepted by ApJ on April 12, 2010.
High resolution figures and full length versions of tables 6, 8 and 10 can be
accessed at http://www.astronomy.ohio-state.edu/~khan/redstars
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