1,828 research outputs found
SDSS J0349-0059 is a GW Virginis star
High speed photometric observations of the spectroscopically-discovered PG
1159 star SDSS J034917.41-005917.9 in 2007 and 2009 reveal a suite of pulsation
frequencies in the range of 1038 - 3323 microHz with amplitudes between 3.5 and
18.6 mmag. SDSS J034917.41-005917.9 is therefore a member of the GW Vir class
of pulsating pre-white dwarfs. We have identified 10 independent pulsation
frequencies that can be fitted by an asymptotic model with a constant period
spacing of 23.61 +/- 0.21 s, presumably associated with a sequence of l = 1
modes. The highest amplitude peak in the suite of frequencies shows evidence
for a triplet structure, with a frequency separation of 14.4 microHz. Five of
the identified frequencies do not fit the l = 1 sequence, but are, however,
well-modeled by an independent asymptotic sequence with a constant period
spacing of 11.66 +/- 0.13 s. It is unclear to which l mode these frequencies
belong.Comment: Accepted for publication in MNRAS; 5 pages, 6 figures and 4 table
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Interrogating cellular perception and decision making with optogenetic tools.
Optogenetics promises to deepen our understanding of how cells perceive and respond to complex and dynamic signals and how this perception regulates normal and abnormal function. In this study, we present our vision for how these nascent tools may transform our view of fundamental cell biological processes
A conceptual analytics model for an outcome-driven quality management framework as part of professional healthcare education
BACKGROUND: Preparing the future health care professional workforce in a changing world is a significant undertaking. Educators and other decision makers look to evidence-based knowledge to improve quality of education. Analytics, the use of data to generate insights and support decisions, have been applied successfully across numerous application domains. Health care professional education is one area where great potential is yet to be realized. Previous research of Academic and Learning analytics has mainly focused on technical issues. The focus of this study relates to its practical implementation in the setting of health care education. OBJECTIVE: The aim of this study is to create a conceptual model for a deeper understanding of the synthesizing process, and transforming data into information to support educatorsâ decision making. METHODS: A deductive case study approach was applied to develop the conceptual model. RESULTS: The analytics loop works both in theory and in practice. The conceptual model encompasses the underlying data, the quality indicators, and decision support for educators. CONCLUSIONS: The model illustrates how a theory can be applied to a traditional data-driven analytics approach, and alongside the context- or need-driven analytics approach
Boundary layer flow induced by waves with acceleration skewness
Young Coastal Scientists and Engineers Conference 2007, PlymouthPeer reviewedPostprin
Nova Scorpii 1941 (V697 Sco): A Probable Intermediate Polar
V697 Sco, the remnant of Nova Scorpii 1941 and currently at V ~ 20.0, is
found from photometric observations to have the characteristics of an
intermediate polar (IP) with an orbital period (Porb) of 4.49 h and a rotation
period (Prot) of 3.31 h. It therefore appears to be a member of the rare class
of IPs where Prot ~ Porb, which are probably discless systems. The prominence
of the modulation at 0.5 Prot, and its orbital sidebands, indicates two-pole
accretion.Comment: To appear in the November 2002 issue of PAS
Simultaneous X-ray/optical observations of GX 9+9 (4U 1728-16)
We report on the results of the first simultaneous X-ray (RXTE) and optical
(SAAO) observations of the luminous low mass X-ray binary (LMXB) GX 9+9 in 1999
August. The high-speed optical photometry revealed an orbital period of 4.1958
hr and confirmed previous observations, but with greater precision. No X-ray
modulation was found at the orbital period. On shorter timescales, a possible
1.4-hr variability was found in the optical light curves which might be related
to the mHz quasi-periodic oscillations seen in other LMXBs. We do not find any
significant X-ray/optical correlation in the light curves. In X-rays, the
colour-colour diagram and hardness-intensity diagram indicate that the source
shows characteristics of an atoll source in the upper banana state, with a
correlation between intensity and spectral hardness. Time-resolved X-ray
spectroscopy suggests that two-component spectral models give a reasonable fit
to the X-ray emission. Such models consist of a blackbody component which can
be interpreted as the emission from an optically thick accretion disc or an
optically thick boundary layer, and a hard Comptonized component for an
extended corona.Comment: 19 pages, 13 figures; accepted for publication in MNRA
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