20,333 research outputs found
A Bayesian method for detecting stellar flares
We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares
in light curve data. We assume flares are described by a model in which there
is a rapid rise with a half-Gaussian profile, followed by an exponential decay.
Our signal model also contains a polynomial background model. This is required
to fit underlying light curve variations that are expected in the data, which
could otherwise partially mimic a flare. We characterise the false alarm
probability and efficiency of this method and compare it with a simpler
thresholding method based on that used in Walkowicz et al (2011). We find our
method has a significant increase in detection efficiency for low
signal-to-noise ratio (S/N) flares. For a conservative false alarm probability
our method can detect 95% of flares with S/N less than ~20, as compared to S/N
of ~25 for the simpler method. As an example we have applied our method to a
selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars
with a total of 1873 flares after vetos have been applied. For these flares we
have characterised their durations and and signal-to-noise ratios.Comment: Accepted for MNRAS. The code used for the analysis can be found at
https://github.com/BayesFlare/bayesflare/releases/tag/v1.0.
Planet formation around stars of various masses: The snow line and the frequency of giant planets
We use a semi-analytic circumstellar disk model that considers movement of
the snow line through evolution of accretion and the central star to
investigate how gas giant frequency changes with stellar mass. The snow line
distance changes weakly with stellar mass; thus giant planets form over a wide
range of spectral types. The probability that a given star has at least one gas
giant increases linearly with stellar mass from 0.4 M_sun to 3 M_sun. Stars
more massive than 3 M_sun evolve quickly to the main-sequence, which pushes the
snow line to 10-15 AU before protoplanets form and limits the range of disk
masses that form giant planet cores. If the frequency of gas giants around
solar-mass stars is 6%, we predict occurrence rates of 1% for 0.4 M_sun stars
and 10% for 1.5 M_sun stars. This result is largely insensitive to our assumed
model parameters. Finally, the movement of the snow line as stars >2.5 M_sun
move to the main-sequence may allow the ocean planets suggested by Leger et.
al. to form without migration.Comment: Accepted to ApJ. 12 pages of emulateap
Evidence of Nodal Line in the Superconducting Gap Symmetry of Noncentrosymmetric ThCoC
The newly discovered noncentrosymmetric superconductor ThCoC exhibits
numerous unconventional behavior in the field dependent heat capacity data.
Here we present the first measurement of the gap symmetry of ThCoC by
muon spin rotation/relaxation SR) measurements. Temperature dependence of
the magnetic penetration depth measured using the transverse field SR
measurement reveal the evidence of nodal pairing symmetry. To understand these
findings, we carry out the calculations of superconducting pairing eigenvalue
and eigenfunction symmetry due to the spin-fluctuation mechanism, by directly
implemented the {\it ab-initio} band structures. We find that the system
possesses a single Fermi surface with considerable three-dimensionality, and
hence a strong nesting along the -direction. Such a nesting promotes a
superconducting pairing with a -like symmetry with a prominent nodal
line on the plane. The result agrees well with the experimental
data.Comment: 3 pages, 5 figure
Implementation frameworks for polypharmacy management within healthcare organisations: a scoping review.
Several guidelines support polypharmacy management in individual patients. More organisational-level focus is needed on the use of implementation frameworks. The aim of this scoping review was to characterise the peer-reviewed literature on implementation frameworks, focussing on barriers and facilitators to implementation at organisational level in the context of polypharmacy management. A scoping review protocol was devised, supporting retrieval of studies published in English, reporting from any sector of practice. Medline, International Pharmaceutical Abstracts, Cumulative Index of Nursing and Allied Health Literature and Business Source Complete were searched to January 2022 using Medical Subject Headings including: 'polypharmacy', 'deprescriptions', 'strategic planning' and 'organizational innovation'. A narrative approach to data synthesis was applied. Searching, data extraction and synthesis were undertaken independently by two reviewers. After screening 797 records, eight papers remained. Two were descriptive, outlining details of specific initiatives; six used qualitative methods to explore determinants for implementation, including barriers and enablers. Barriers at the organisation level included: poor organisational culture with a lack of sense of urgency and national plans, resource availability and communication issues including patient information and at transitions of care. Organisational facilitators included availability of government funding and regulatory environment promoting patient safety, a national emphasis on quality of care for older adults, co-ordinated national efforts and local evidence. Limited literature focusses on the use of implementation frameworks at organisational levels. This review highlights the need for further work on implementation frameworks in this context to help achieve effective organisational change
A qualitative exploration of key stakeholders’ views and perceptions in relation to organisational change for the implementation of polypharmacy management in Oman.
Polypharmacy contributes to patient non-adherence and increases medication harm. Barriers to implementation prevent desired outcomes when addressing inappropriate polypharmacy at organisational levels and there is a need for theory-based strategies for change management. The objective of this study was to explore the views and perceptions of key stakeholders in relation to organisational change for the development and implementation of a polypharmacy management healthcare strategy in Oman. Qualitative face to face interviews started in March 2022 with key stakeholders in Oman Ministry of Health (MOH) including leaders from practice of Medical, pharmacy and nursing as well as academic leaders from school of medicine, pharmacy and nursing. The interview schedule developed based on a scoping review, Kotter's first three steps of leading change and grounded in the consolidated Framework for Implementation Research (CIFR). Interviews were digitally recorded, transcribed, and analysed independently by at least two researchers using CFIR as a coding framework. Ethics approval was in place prior to data generation. Identified themes related to views and perceptions of key stakeholders in relation to the topic area. To date, ten interviews have been conducted with directors of medical (n=2), pharmacy (2) and nursing practice (1), academic healthcare leaders (3), a healthcare policy developer (1) and patient safety leader (1). Additional interviews are planned and will continue until data saturation. Emerging themes show that participants have views that polypharmacy is a burden on healthcare services and there is a need for organisational change in relation to polypharmacy management. Perceptions of reported organisational level barriers were; fragmentation of care, lack of systems for coordination among healthcare providers, absence of electronic link between the government and private sector, lack of sense of urgency among leaders regarding the polypharmacy and shortage of pharmacists. Facilitators were; the presence of well-developed electronic health system and leadership support. There is a need for for organisational change in relation to polypharmacy management in Oman. Further research is needed to obtain consensus of Omani stakeholders on the plan for a strategic framework for organisational change in relation to polypharmacy management
Constraints on the Primordial Magnetic Field from
A primordial magnetic field (PMF) can affect the evolution of density field
fluctuations in the early universe.In this paper we constrain the PMF amplitude
and power spectral index by comparing calculated
density field fluctuations with observational data, i.e. the number density
fluctuation of galaxies.We show that the observational constraints on
cosmological density fluctuations, as parameterized by , lead to
strong constraints on the amplitude and spectral index of the PMF.Comment: 11 pages, 1 figure, accepted for publication as Phys. Rev.
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