10,183 research outputs found
Deep 2MASS Photometry of M67 and Calibration of the Main Sequence J-Ks Color Difference as an Age Indicator
We present an analysis of Two Micron All Sky Survey (2MASS) calibration
photometry of the old open cluster M67 (NGC 2682). The proper motion-cleaned
color-magnitude diagram (CMD) resulting from these data extends ~3 magnitudes
deeper than one based on data from the point source catalog. The CMD extends
from above the helium-burning red clump to a faint limit that is more than 7
magnitudes below the main sequence turnoff in the Ks band. After adopting a
reddening of E(B-V) = 0.041 +/- 0.004 and a metal abundance of [Fe/H] = -0.009
+/- 0.009 based on a survey of published values, we fit the unevolved main
sequence of M67 to field main sequence stars with 2MASS photometry and
Hipparcos parallaxes. This analysis yields distance moduli of (m-M)Ks = 9.72
+/- 0.05 and (m-M)o = 9.70 +/- 0.05, which are consistent with published
values. We compare the theoretical isochrones of Girardi et al. and Dotter et
al. to the CMD of M67 and comment on the relative merits of each set of models.
These comparisons suggest an age between 3.5 and 4.0 Gyr for M67. The depth of
the M67 data make them ideal for the calibration of a new age indicator that
has recently been devised by Calamida et al.- the difference in (J-Ks) color
between the main sequence turnoff (TO) and the point on the lower main sequence
where it turns down (TD) and becomes nearly vertical [D(J-Ks)]. Coupled with
deep 2MASS photometry for three other open clusters, NGC 2516, M44, and NGC
6791, we calibrate D(J-Ks) in terms of age and find D(J-Ks) = (3.017 +/- 0.347)
- (0.259 +/- 0.037)*Log Age (yrs).Comment: 19 pages, 9 figures, accepted for publication in The Astrophysical
Journa
Estão os Alunos de MatrÃcula Dupla Preparados para Entrar na Faculdade? Evidências do Estudo Nacional de Artes de Wabash
We examine whether dual enrolled students display greater levels of college readiness than nonparticipants. Advocates assert that dual enrollment improves students’ college readiness, but despite these assertions, few researchers have evaluated this relationship. Moreover, researchers that do consider whether dual enrollment improves college readiness examine this relationship while students participate in dual enrollment or shortly thereafter. Unlike traditional measures of college readiness that tend to emphasize the cognitive domain of college readiness, we use measures that integrate both cognitive and noncognitive domains of college readiness. We find that students who participated in dual enrollment tend to be more college ready than those who did not earn college credit in high school. The exception is that there is no statistical difference between dual enrollees and non-accelerators in their key transition knowledge and skills. The magnitude of the dual enrollment effect is second only to gender. Examinamos si los estudiantes de matriculas duales muestran mayores niveles de preparación para la universidad que los que no participan en ese programa. Los defensores afirman que la doble inscripción mejora la preparación para la universidad de los estudiantes, pero a pesar de estas afirmaciones, pocos investigadores han evaluado esta relación. Por otra parte, los investigadores que si consideran que la doble matrÃcula mejora la preparación universitaria examinan esta relación mientras los estudiantes participan en doble inscripción o poco después. A diferencia de las medidas tradicionales de preparación para la universidad que tienden a enfatizar el dominio cognitivo de preparación para la universidad, utilizamos medidas que integran dominios cognitivos y no-cognitivos de preparación para la universidad. Encontramos que los estudiantes que participaron en la doble matrÃcula tienden a ser más preparados para la universidad que los que no ganan créditos universitarios en la escuela secundaria. La excepción es que no hay diferencia estadÃstica entre los inscritos en matriculas duales y los que no en conocimientos y habilidades importantes para  los estudios universitarios. El efecto de magnitud de las matriculas duales sólo es superado por el género.Examinamos se os alunos de inscrição duplas mostram nÃveis mais elevados de preparação para a faculdade do que aqueles que não participam nesse programa. Os defensores argumentam que a dupla inscrição melhor preparação para os estudantes universitários, mas apesar destas afirmações, poucos pesquisadores avaliaram essa relação. Além disso, os pesquisadores acreditam que, se a dupla prontidão faculdade de inscrição melhora a examinar esta relação, enquanto os alunos participam de matrÃcula dupla ou pouco depois. Ao contrário de medidas tradicionais de prontidão para faculdade que tendem a enfatizar o domÃnio cognitivo de preparação para a faculdade, usamos medidas que integram domÃnios cognitivos e não-cognitivas na preparação para a faculdade. Descobrimos que os alunos que participaram do programa da matrÃcula dupla tendem a estar mais preparados para a faculdade do que aqueles que não ganham créditos universitários na escola. A exceção é que não há diferença estatÃstica entre os alunos de dupla inscrição e os que não em conhecimentos e habilidades importantes para a faculdade. A magnitude do efeito da dupla inscrição só é superado por gênero
Application of Data Compression Methods to the Redshift-space distortions of the PSCz galaxy catalogue
We apply a spherical harmonic analysis to the Point Source Redshift Survey (PSCz), to compute the real-space galaxy power spectrum and the degree of redshift distortion caused by peculiar velocities. We employ new parameter eigenvector and hierarchical data compression techniques, allowing a much larger number of harmonic modes to be included, and correspondingly smaller error bars. Using 4644 harmonic modes, compressed to 2278, we find that the IRAS redshift-space distortion parameter is and the amplitude of galaxy clustering on a scale of is . Combining these we find the amplitude of mass perturbations is . A preliminary model fitting analysis combining the PSCz amplitudes with the CMB and abundance of clusters yields the cosmological matter density parameter , the amplitude of primordial perturbations , and the IRAS bias parameter
Redshift Distortions and Clustering in the PSCz Survey
We have constrained the redshift-distortion parameter and the real-space power spectrum of the IRAS PSCz survey using a spherical-harmonic redshift-distortion analysis combined with a data compression method which is designed to deal with correlated parameters. Our latest result, , strongly rules out
EduSAT: A Pedagogical Tool for Theory and Applications of Boolean Satisfiability
Boolean Satisfiability (SAT) and Satisfiability Modulo Theories (SMT) are
widely used in automated verification, but there is a lack of interactive tools
designed for educational purposes in this field. To address this gap, we
present EduSAT, a pedagogical tool specifically developed to support learning
and understanding of SAT and SMT solving. EduSAT offers implementations of key
algorithms such as the Davis-Putnam-Logemann-Loveland (DPLL) algorithm and the
Reduced Order Binary Decision Diagram (ROBDD) for SAT solving. Additionally,
EduSAT provides solver abstractions for five NP-complete problems beyond SAT
and SMT. Users can benefit from EduSAT by experimenting, analyzing, and
validating their understanding of SAT and SMT solving techniques. Our tool is
accompanied by comprehensive documentation and tutorials, extensive testing,
and practical features such as a natural language interface and SAT and SMT
formula generators, which also serve as a valuable opportunity for learners to
deepen their understanding. Our evaluation of EduSAT demonstrates its high
accuracy, achieving 100% correctness across all the implemented SAT and SMT
solvers. We release EduSAT as a python package in .whl file, and the source can
be identified at https://github.com/zhaoy37/SAT_Solver
TOX3 mutations in breast cancer
TOX3 maps to 16q12, a region commonly lost in breast cancers and recently implicated in the risk of developing breast cancer. However, not much is known of the role of TOX3 itself in breast cancer biology. This is the first study to determine the importance of TOX3 mutations in breast cancers. We screened TOX3 for mutations in 133 breast tumours and identified four mutations (three missense, one in-frame deletion of 30 base pairs) in six primary tumours, corresponding to an overall mutation frequency of 4.5%. One potentially deleterious missense mutation in exon 3 (Leu129Phe) was identified in one tumour (genomic DNA and cDNA). Whilst copy number changes of 16q12 are common in breast cancer, our data show that mutations of TOX3 are present at low frequency in tumours. Our results support that TOX3 should be further investigated to elucidate its role in breast cancer biology.Breast Cancer Research Foundation grant; University of Cambridge; Cancer Research UK; Hutchison Whampoa Limited; NIHR Cambridge Biomedical Research Centre; Marie Curie Career Integration Grant; Cancer Research UK [16942]; National Institute for Health Research [NF-SI-0611-10154
Exact Numerical Solution of the BCS Pairing Problem
We propose a new simulation computational method to solve the reduced BCS
Hamiltonian based on spin analogy and submatrix diagonalization. Then we
further apply this method to solve superconducting energy gap and the results
are well consistent with those obtained by Bogoliubov transformation method.
The exponential problem of 2^{N}-dimension matrix is reduced to the polynomial
problem of N-dimension matrix. It is essential to validate this method on a
real quantumComment: 7 pages, 3 figure
Proposal of Quantum Simulation of Pairing Model on an NMR Quantum Computer
We give out a proposal of quantum simulation of pairing model on an NMR
quantum computer. In our proposal, we choose an appropriate initial state which
can be easily prepared in experiment. Making use of feature of NMR measure and
the technology of the second (discrete) Fourier transformation, our theoretical
scheme can obtain the spectrum of paring model in principle. We concretely
discuss the case in the concerned subspaces of pairing model and then, as an
example, give out a simple initial state to get the gap of two the lowest
energy levels in the given subspace. The quantum simulation to get more
differences of energy levels is able to be discussed similarly.Comment: 5 pages, no figures, introducing and conclusion paragraphes are
revise
Impact of a case-management intervention for reducing emergency attendance on primary care: randomised control trial
BACKGROUND:
The impact on primary care workload of case-management interventions to reduce emergency department (ED) attendances is unknown.
AIM:
To examine the impact of a telephone-based case-management intervention targeting people with high ED attendance on primary care use.
DESIGN AND SETTING:
A single-site data extract from a larger randomised control trial, using the patient-level data from primary care electronic health records (2015–2020), was undertaken.
METHOD:
A total of 363 patients at high risk of ED usage were randomised to receive a 6-month case-management intervention (253 patients) or standard care (110 patients). Poisson regression models were used to calculate monthly rates of primary care use over time for the 2 years post-randomisation, comparing both arms. Usage was subclassified into face-to-face, telephone, letter, and community and secondary care referrals, stratified by patient demographics.
RESULTS:
No significant difference was found in the mean annual rate of primary care events between the intervention and control arms (P = 0.70). Secondary care referrals saw a 26% reduction in the mean annual referral rate (incident rate ratio [IRR] 0.74, 95% confidence interval [CI] = 0.64 to 0.86, P<0.001) and letters sent increased by 6% in the intervention arm compared with the control arm (IRR 1.06, 95% CI = 1.01 to 1.11, P = 0.01). In the case-managed arm, in patients aged ≥80 years there was a 33% increase in primary care usage (IRR 1.33, 95% CI = 1.28 to 1.40, P<0.001); with a corresponding 10% decrease in patients aged <80 years when compared with controls (IRR 0.90, 95% CI = 0.87 to 0.92, P<0.001).
CONCLUSION:
A targeted case-management intervention to reduce ED attendances did not increase overall primary care use. Redistribution of usage is seen among some patient groups, particularly older people, which may have important implications for primary healthcare planning
An attractor for dark matter structures
Cosmological simulations of dark matter structures have identified a set of
universal profiles, and similar characteristics have been seen in
non-cosmological simulations. It has therefore been speculated whether these
profiles of collisionless systems relate to accretion and merger history, or if
there is an attractor for the dark matter systems. Here we identify such a
1-dimensional attractor in the 3-dimensional space spanned by the 2 radial
slopes of the density and velocity dispersion, and the velocity anisotropy.
This attractor effectively removes one degree of freedom from the Jeans
equation. It also allows us to speculate on a new fluid interpretation for the
Jeans equation, with an effective polytropic index for the dark matter
particles between 1/2 and 3/4. If this attractor solution holds for other
collisionless structures, then it may hold the key to break the mass-anisotropy
degeneracy, which presently prevents us from measuring the mass profiles in
dwarf galaxies uniquely.Comment: 7 pages, 2 figures, comments welcom
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