490 research outputs found
Approximating RR Lyrae light curves using cubic polynomials
In this paper, we use cubic polynomials to approximate RR Lyrae light curves
and apply the method to HST data of RR Lyraes in the halo of M31. We compare
our method to the standard method of Fourier decomposition and find that the
method of cubic polynomials eliminates virtually all ringing effects and does
so with significantly fewer parameters than the Fourier technique. Further, for
RRc stars the parameters in the fit are all physical. Our study also reveals a
number of additional periodicites in this data not found previously: we find 23
RRc stars, 29 RRab stars and 3 multiperiodic stars.Comment: 6 pages, MNRAS accepte
Ensuring young voices are heard in core outcome set development: international workshops with 70 children and young people.
Plain english summaryResearchers test treatments to ensure these work and are safe. They do this by studying the effects that treatments have on patients by measuring outcomes, such as pain and quality of life. Often research teams measure different outcomes even though each team is studying the same condition. This makes it hard to compare the findings from different studies and it can reduce the accuracy of the treatment advice available to patients. Increasingly, researchers are tackling this problem by developing 'core outcome sets'. These are lists of outcomes that all researchers working on a given condition should measure in their studies. It is important that patients have a voice in the development of core outcome sets and children and young people are no exception. But their voices have rarely been heard when core outcome sets are developed. Researchers are trying to address this problem and make sure that core outcome sets are developed in ways that are suitable for children and young people. As a first step, we held two international workshops with children and young people to listen to their views. They emphasised the importance of motivating young people to participate in developing core outcome sets, making them feel valued, and making the development process more interactive, enjoyable and convenient. We hope this commentary will encourage researchers to include children and young people when developing core outcome sets and to adapt their methods so these are suitable for young participants. Future research is important to examine whether these adaptations are effective.AbstractBackground Different research teams looking at treatments for the same condition often select and measure inconsistent treatment outcomes. This makes it difficult to synthesise the results of different studies, leads to selective outcome reporting and impairs the quality of evidence about treatments. 'Core outcome sets' (COS) can help to address these problems. A COS is an agreed, minimum list of outcomes that researchers are encouraged to consistently measure and report in their studies. Including children and young people (CYP) as participants in the development of COS for paediatric conditions ensures that clinically meaningful outcomes are measured and reported. However, few published COS have included CYP as participants. COS developers have described difficulties in recruiting and retaining CYP and there is a lack of guidance on optimising COS methods for them. We aimed to explore CYP's views on the methods used to develop COS and identify ways to optimise these methods.Main body This commentary summarises discussions during two workshops with approximately 70 CYP (aged 10-18âyears old) at the International Children's Advisory Network Research and Advocacy Summit, 2018. Delegates described what might motivate them to participate in a COS study, including feeling valued, understanding the need for COS and the importance of input from CYP in their development, and financial and other incentives (e.g. certificates of participation). For Delphi surveys, delegates suggested that lists of outcomes should be as brief as possible, and that scoring and feedback methods should be simplified. For consensus meetings, delegates advised preparing CYP in advance, supporting them during meetings (e.g. via mentors) and favoured arrangements whereby CYP could meet separately from parents and other stakeholders. Overall, they wanted COS methods that were convenient, enjoyable and engaging.Conclusion This commentary points to the limitations of the methods currently used to develop COS with CYP. It also points to ways to motivate CYP to participate in COS studies and to enhancements of methods to make participation more engaging for CYP. Pending much needed research on COS methods for CYP, the perspectives offered in the workshops should help teams developing COS in paediatrics and child health
SkyMapper Southern Survey: First Data Release (DR1)
We present the first data release (DR1) of the SkyMapper Southern Survey, a
hemispheric survey carried out with the SkyMapper Telescope at Siding Spring
Observatory in Australia. Here, we present the survey strategy, data
processing, catalogue construction and database schema. The DR1 dataset
includes over 66,000 images from the Shallow Survey component, covering an area
of 17,200 deg in all six SkyMapper passbands , while the full area
covered by any passband exceeds 20,000 deg. The catalogues contain over 285
million unique astrophysical objects, complete to roughly 18 mag in all bands.
We compare our point-source photometry with PanSTARRS1 DR1 and note an
RMS scatter of 2%. The internal reproducibility of SkyMapper photometry is on
the order of 1%. Astrometric precision is better than 0.2 arcsec based on
comparison with Gaia DR1. We describe the end-user database, through which data
are presented to the world community, and provide some illustrative science
queries.Comment: 31 pages, 19 figures, 10 tables, PASA, accepte
Conditional Intensity and Gibbsianness of Determinantal Point Processes
The Papangelou intensities of determinantal (or fermion) point processes are
investigated. These exhibit a monotonicity property expressing the repulsive
nature of the interaction, and satisfy a bound implying stochastic domination
by a Poisson point process. We also show that determinantal point processes
satisfy the so-called condition which is a general form of
Gibbsianness. Under a continuity assumption, the Gibbsian conditional
probabilities can be identified explicitly.Comment: revised and extende
Process parameter optimisation of laser clad iron based alloy: predictive models of deposition efficiency, porosity and dilution
As a candidate coating material for heat-exchanger surfaces in commercial power generation boiler, an amorphous/glass forming Fe-Cr-B alloy NanoSteel SHS 7170 was deposited by a 2âŻkW fibre laser onto a boiler grade steel substrate (15Mo3). A comprehensive trial with 28 single track optimisation runs was carried out to develop models of the influence of three processing parameters, laser power, laser traverse speed and powder feed rate, on powder deposition efficiency, dilution and porosity. It was found that deposition efficiency is dependent on laser power and powder feed rate, increasing with increasing power and decreasing powder feed rate when tested within the parameter window of laser power ranging from 0.4 to 2âŻkW; traverse speed varying from 150 to 1200âŻmmâŻminâ1; and powder feed rate varying from 4 to 10âŻgâŻminâ1. Similarly, it was found that dilution is also dependent on laser power and powder feed rate. Dilution increases with increasing power and decreases with increasing powder feed rate within the same parameter window discussed above. This means that through processing parameter selection, these properties can be adjusted to suit their application. Porosity was found to be independent of processing parameters and instead mostly dependent on the feedstock material. A model was produced for predicting porosity within a powder feedstock, found to be 8.5%. These models were used to successfully produce an optimised coating
The impact of digital technology in care homes on unplanned secondary care usage and associated costs.
BackgroundA substantial number of Emergency Department (ED) attendances by care home residents are potentially avoidable. Health Call Digital Care Homes is an app-based technology that aims to streamline residentsâ care by recording their observations such as vital parameters electronically. Observations are triaged by remote clinical staff. This study assessed the effectiveness of the Health Call technology to reduce unplanned secondary care usage and associated costs.MethodsA retrospective analysis of health outcomes and economic impact based on an intervention. The study involved 118 care homes across the North East of UK from 2018 to 2021. Routinely collected NHS secondary care data from County Durham and Darlington NHS Foundation Trust was linked with data from the Health Call app. Three outcomes were modelled monthly using Generalised Linear Mixed Models: counts of emergency attendances, emergency admissions and length of stay of emergency admissions. A similar approach was taken for costs. The impact of Health Call was tested on each outcome using the models.FindingsData from 8,702 residents were used in the analysis. Results show Health Call reduces the number of emergency attendances by 11% [6â15%], emergency admissions by 25% [20â39%] and length of stay by 11% [3â18%] (with an additional month-by-month decrease of 28% [24â34%]). The cost analysis found a cost reduction of ÂŁ57 per resident in 2018, increasing to ÂŁ113 in 2021.InterpretationThe introduction of a digital technology, such as Health Call, could significantly reduce contacts with and costs resulting from unplanned secondary care usage by care home residents
Carbon Abundances of Three Carbon-Enhanced Metal-Poor Stars from High-Resolution Gemini-S/bHROS Spectra of the 8727A [C I] Line
We present the results from an analysis of the 8727ang forbidden [C I] line
in high-resolution Gemini-S/bHROS spectra of three CEMP stars. We find the
[C/Fe] ratios based on the [C I] abundances of the two most Fe-rich stars in
our sample (HIP 0507-1653: [Fe/H] = -1.42 and HIP 0054-2542: [Fe/H] = -2.66) to
be in good agreement with previously determined CH and C_2 line-based values.
For the most Fe-deficient star in our sample (HIP 1005-1439: [Fe/H] = -3.08),
however, the [C/Fe] ratio is found to be 0.34 dex lower than the published
molecular-based value. We have carried out 3D local thermodynamic equilibrium
(LTE) calculations for [C I], and the resulting corrections are found to be
modest for all three stars, suggesting that the discrepancy between the [C I]
and molecular-based C abundances of HIP 1005-1439 is due to more severe 3D
effects on the molecular lines. Carbon abundances are also derived from C I
high-excitation lines and are found to be 0.45-0.64 dex higher than the [C
I]-based abundances. Previously published non-LTE C I abundance corrections
bring the [C I] and C I abundances into better agreement; however, targeted
NLTE calculations for CEMP stars are clearly needed. We have also derived the
abundances of N, K, and Fe for each star. The Fe abundances agree well with
previously derived values, and the K abundances are similar to those of
C-normal metal-poor stars. Nitrogen abundances have been derived from resolved
lines of the CN red system. The abundances are found to be approximately 0.44
dex larger than literature values, which have been derived from CN blue bands
near 3880 and 4215 ang. We discuss evidence that suggests that analyses of the
CN blue system bands underestimate the N abundances of metal-poor giants.Comment: Accepted for publication in AJ; 42 pages, 6 figures, 7 table
Absence of Phase Transition for Antiferromagnetic Potts Models via the Dobrushin Uniqueness Theorem
We prove that the -state Potts antiferromagnet on a lattice of maximum
coordination number exhibits exponential decay of correlations uniformly at
all temperatures (including zero temperature) whenever . We also prove
slightly better bounds for several two-dimensional lattices: square lattice
(exponential decay for ), triangular lattice (), hexagonal
lattice (), and Kagom\'e lattice (). The proofs are based on
the Dobrushin uniqueness theorem.Comment: 32 pages including 3 figures. Self-unpacking file containing the tex
file, the needed macros (epsf.sty, indent.sty, subeqnarray.sty, and
eqsection.sty) and the 3 ps file
Gentle Perturbations of the Free Bose Gas I
It is demonstrated that the thermal structure of the noncritical free Bose
Gas is completely described by certain periodic generalized Gaussian stochastic
process or equivalently by certain periodic generalized Gaussian random field.
Elementary properties of this Gaussian stochastic thermal structure have been
established. Gentle perturbations of several types of the free thermal
stochastic structure are studied. In particular new models of non-Gaussian
thermal structures have been constructed and a new functional integral
representation of the corresponding euclidean-time Green functions have been
obtained rigorously.Comment: 51 pages, LaTeX fil
Multiple phases of human occupation in Southeast Arabia between 210,000 and 120,000 years ago
Changing climatic conditions are thought to be a major control of human presence in Arabia during the Paleolithic. Whilst the Pleistocene archaeological record shows that periods of increased monsoon rainfall attracted human occupation and led to increased population densities, the impact of arid conditions on human populations in Arabia remains largely speculative. Here, we present data from Jebel Faya in Southeast (SE) Arabia, which document four periods of human occupation between c. 210,000 and 120,000 years ago. The Jebel Faya record indicates that human occupation of SE Arabia was more regular and not exclusively linked to major humid periods. Our data show that brief phases of increased rainfall additionally enabled human settlement in the Faya region. These results imply that the mosaic environments in SE Arabia have likely formed a population refugia at the end of the Middle and the beginning of the Late PleistoceneOpen Access funding enabled and organized by Projekt DEAL.https://www.nature.com/srepBiochemistryGeneticsMicrobiology and Plant Patholog
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