674 research outputs found

    The Distribution of Nearby Stars in Velocity Space Inferred from Hipparcos Data

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    (abridged) The velocity distribution f(v) of nearby stars is estimated, via a maximum- likelihood algorithm, from the positions and tangential velocities of a kinematically unbiased sample of 14369 stars observed by the HIPPARCOS satellite. f(v) shows rich structure in the radial and azimuthal motions, v_R and v_phi, but not in the vertical velocity, v_z: there are four prominent and many smaller maxima, many of which correspond to well known moving groups. While samples of early-type stars are dominated by these maxima, also up to 25% of red main-sequence stars are associated with them. These moving groups are responsible for the vertex deviation measured even for samples of late-type stars; they appear more frequently for ever redder samples; and as a whole they follow an asymmetric-drift relation, in the sense that those only present in red samples predominantly have large |v_R| and lag in v_phi w.r.t. the local standard of rest (LSR). The question arise, how these old moving groups got on their eccentric orbits. A plausible mechanism, known from solar system dynamics, which is able to manage a shift in orbit space involves locking into an orbital resonance. Apart from these moving groups, there is a smooth background distribution, akin to Schwarzschild's ellipsoidal model, with axis ratio of about 1:0.6:0.35 in v_R, v_phi, and v_z. The contours are aligned with the vrv_r direction, but not w.r.t. the v_phi and v_z axes: the mean v_z increases for stars rotating faster than the LSR. This effect can be explained by the stellar warp of the Galactic disk. If this explanation is correct, the warp's inner edge must not be within the solar circle, while its pattern rotates with frequency of about 13 km/s/kpc or more retrograde w.r.t. the stellar orbits.Comment: 16 pages LaTeX (aas2pp4.sty), 6 figures, accepted by A

    Should I Take Aspirin? (SITA): RCT of a decision aid for cancer chemoprevention.

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    Background Australian guidelines recommend that all people aged 50-70 years old consider taking low-dose aspirin to reduce the risk of colorectal cancer (CRC). Aim To determine the effect of a consultation with a researcher in general practice using a decision aid about taking low-dose aspirin to prevent CRC on informed decision-making and low-dose aspirin uptake compared to a general CRC prevention brochure. Design and Setting Individually randomised controlled trial in six general practices in Victoria, Australia, from October 2020 to March 2021. Method Patients aged 50-70 years attending a general practitioner (GP) were recruited consecutively. The intervention was a consultation using a decision aid to discuss taking aspirin to reduce CRC risk; control consultations discussed reducing CRC risk generally. The self-reported co-primary outcomes were informed choices about taking aspirin at one month and low-dose aspirin uptake at six months. Results 261 participants (86% of eligible patients) were randomised into trial arms (129 intervention, 132 control). 17.7% (20/113) of intervention and 7.6% (9/118) control participants reported making an informed choice at one month, an estimated 9.1% (95% CI 0.29% to 18.5) between-arm difference in proportions [odds ratio (OR) 2.47 (97.5% CI:0.94 to 6.52) p=0.074]. The proportions of individuals who reported using aspirin at six months were: 10.2% (12/118) intervention vs 13.8% (16/116) control (estimated between-arm difference: -4.0% (95% CI: -13.5 to 5.5); [OR= 0.68 (97.5% CI:0.27 to 1.70), p= 0.692]. Conclusion The decision aid improved informed decision-making; but has little effect on long-term regular use of aspirin to reduce CRC risk

    The Test Re-Test Reliability of A Novel Single Leg Hop Test (T-Drill Hop Test)

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    # Background Functional training and testing are an important part of a comprehensive rehabilitation program stressing the neuromuscular system in ways that simulate athletic performance to help determine criteria for return to sport. There are numerous single leg hop tests that have been used for these purposes, however, the validity and clinical relevance has been questioned. Many of the functional performance tests assess only the sagittal plane or forward direction and may only partially assess a person’s athletic abilities. There is a need for reliable and valid functional tests to assess in a multi-directional manner. # Purpose/Hypothesis The purpose of this study is to determine the test re-test reliability of a novel multi-directional timed single leg hop test (T-Drill Hop Test) for use in rehabilitation and performance assessments. # Study Design Cross-sectional reliability study. # Methods Fifty healthy recreationally active college age subjects, (23 males and 27 females) between the ages of 18 and 35, (mean age 23.48 with SD 3.82) consented to perform the test. The subjects hopped along a 10ft. x 10ft. “T” shaped course. Subjects performed two timed maximum effort trials of the T-Drill Hop Test on each leg with an interval of 3-7 days between the two testing days. Intraclass Correlation Coefficients (ICC) were calculated to determine intersession reliability. # Results The inter-rater reliability (ICC’s) for the entire group of 50 subjects ranged between .98 and 1.00 suggesting excellent reliability. The bilateral comparison, utilizing paired t-tests, of the T-Drill Hop Test demonstrated no significant differences between the time scores for the dominant and non-dominant legs for either males or females (p>.05). # Conclusion This study demonstrates the T-Drill Hop Test has excellent test re-test reliability. These results are important prior to validation and utilization as a clinical functional performance test. # Levels of Evidence Level

    The SCRIPT trial: study protocol for a randomised controlled trial of a polygenic risk score to tailor colorectal cancer screening in primary care

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    BACKGROUND: Polygenic risk scores (PRSs) can predict the risk of colorectal cancer (CRC) and target screening more precisely than current guidelines using age and family history alone. Primary care, as a far-reaching point of healthcare and routine provider of cancer screening and risk information, may be an ideal location for their widespread implementation. METHODS: This trial aims to determine whether the SCRIPT intervention results in more risk-appropriate CRC screening after 12 months in individuals attending general practice, compared with standard cancer risk reduction information. The SCRIPT intervention consists of a CRC PRS, tailored risk-specific screening recommendations and a risk report for participants and their GP, delivered in general practice. Patients aged between 45 and 70 inclusive, attending their GP, will be approached for participation. For those over 50, only those overdue for CRC screening will be eligible to participate. Two hundred and seventy-four participants will be randomised to the intervention or control arms, stratified by general practice, using a computer-generated allocation sequence. The primary outcome is risk-appropriate CRC screening after 12 months. For those in the intervention arm, risk-appropriate screening is defined using PRS-derived risk; for those in the control arm, it is defined using family history and national screening guidelines. Timing, type and results of the previous screening are considered in both arms. Objective health service data will capture screening behaviour. Secondary outcomes include cancer-specific worry, risk perception, predictors of CRC screening behaviour, screening intentions and health service use at 1, 6 and 12 months post-intervention delivery. DISCUSSION: This trial aims to determine whether a PRS-derived personalised CRC risk estimate delivered in primary care increases risk-appropriate CRC screening. A future population risk-stratified CRC screening programme could incorporate risk assessment within primary care while encouraging adherence to targeted screening recommendations. TRIAL REGISTRATION: Australian and New Zealand Clinical Trial Registry ACTRN12621000092897p. Registered on 1 February 2021. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06734-7

    In search of phylogenetic congruence between molecular and morphological data in bryozoans with extreme adult skeletal heteromorphy

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    peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tsab20© Crown Copyright 2015. This document is the author's final accepted/submitted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it

    A Census of Oxygen in Star-Forming Galaxies: An Empirical Model Linking Metallicities, Star Formation Rates and Outflows

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    In this contribution we present the first census of oxygen in star-forming galaxies in the local universe. We examine three samples of galaxies with metallicities and star formation rates at z = 0.07, 0.8 and 2.26, including the SDSS and DEEP2 surveys. We infer the total mass of oxygen produced and mass of oxygen found in the gas-phase from our local SDSS sample. The star formation history is determined by requiring that galaxies evolve along the relation between stellar mass and star formation rate observed in our three samples. We show that the observed relation between stellar mass and star formation rate for our three samples is consistent with other samples in the literature. The mass-metallicity relation is well established for our three samples and from this we empirically determine the chemical evolution of star-forming galaxies. Thus, we are able to simultaneously constrain the star formation rates and metallicities of galaxies over cosmic time allowing us to estimate the mass of oxygen locked up in stars. Combining this work with independent measurements reported in the literature we conclude that the loss of oxygen from the interstellar medium of local star-forming galaxies is likely to be a ubiquitous process with the oxygen mass loss scaling (almost) linearly with stellar mass. We estimate the total baryonic mass loss and argue that only a small fraction of the baryons inferred from cosmological observations accrete onto galaxies.Comment: 24 pages, 18 figures. Accepted for publication in Ap

    High-accuracy determination of the U 238 / U 235 fission cross section ratio up to ≈1 GeV at n-TOF at CERN

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    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOIThe U238 to U235 fission cross section ratio has been determined at n-TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3-4%. The data collected at n-TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n-TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ≈1 GeV.Peer reviewedFinal Published versio

    Older adults' beliefs about physician-estimated life expectancy: a cross-sectional survey

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    BACKGROUND: Estimates of life expectancy assist physicians and patients in medical decision-making. The time-delayed benefits for many medical treatments make an older adult's life expectancy estimate particularly important for physicians. The purpose of this study is to assess older adults' beliefs about physician-estimated life expectancy. METHODS: We performed a mixed qualitative-quantitative cross-sectional study in which 116 healthy adults aged 70+ were recruited from two local retirement communities. We interviewed them regarding their beliefs about physician-estimated life expectancy in the context of a larger study on cancer screening beliefs. Semi-structured interviews of 80 minutes average duration were performed in private locations convenient to participants. Demographic characteristics as well as cancer screening beliefs and beliefs about life expectancy were measured. Two independent researchers reviewed the open-ended responses and recorded the most common themes. The research team resolved disagreements by consensus. RESULTS: This article reports the life-expectancy results portion of the larger study. The study group (n = 116) was comprised of healthy, well-educated older adults, with almost a third over 85 years old, and none meeting criteria for dementia. Sixty-four percent (n = 73) felt that their physicians could not correctly estimate their life expectancy. Sixty-six percent (n = 75) wanted their physicians to talk with them about their life expectancy. The themes that emerged from our study indicate that discussions of life expectancy could help older adults plan for the future, maintain open communication with their physicians, and provide them knowledge about their medical conditions. CONCLUSION: The majority of the healthy older adults in this study were open to discussions about life expectancy in the context of discussing cancer screening tests, despite awareness that their physicians' estimates could be inaccurate. Since about a third of participants perceived these discussions as not useful or even harmful, physicians should first ascertain patients' preferences before discussing their life expectancies

    Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF

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    The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards
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