1,297 research outputs found

    Will Gravitational Wave Sirens Determine the Hubble Constant?

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    Lack of knowledge about the background expansion history of the Universe from independent observations makes it problematic to obtain a precise and accurate estimation of the Hubble constant H0H_0 from gravitational wave standard sirens, even with electromagnetic counterpart redshifts. Simply fitting simultaneously for the matter density in a flat \lcdm\ model can reduce the precision on H0H_0 from 1\% to 5\%, while not knowing the actual background expansion model of the universe (e.g.\ form of dark energy) can introduce substantial bias in estimation of the Hubble constant. When the statistical precision is at the level of 1\% uncertainty on H0H_0, biases in non-\lcdm\ cosmologies that are consistent with current data could reach the 3σ\sigma level. To avoid model-dependent biases, statistical techniques that are appropriately agnostic about model assumptions need to be employed.Comment: 7 pages, 7 figure

    Cluster Model for Near-barrier Fusion Induced by Weakly Bound and Halo Nuclei

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    The influence on the fusion process of coupling transfer/breakup channels is investigated for the medium weight 6,7^{6,7}Li+59^{59}Co systems in the vicinity of the Coulomb barrier. Coupling effects are discussed within a comparison of predictions of the Continuum Discretized Coupled-Channels model. Applications to 6^{6}He+59^{59}Co induced by the borromean halo nucleus 6^{6}He are also proposed.Comment: 5 pages, 3 figures, FINUSTAR2 Conference, Aghios Nikolaus, Crete, Greece. 10-14 September 200

    Development of Prognosis in Palliative care Study (PiPS) predictor models to improve prognostication in advanced cancer: prospective cohort study

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    OBJECTIVE: To develop a novel prognostic indicator for use in patients with advanced cancer that is significantly better than clinicians' estimates of survival. DESIGN: Prospective multicentre observational cohort study. SETTING: 18 palliative care services in the UK (including hospices, hospital support teams, and community teams). PARTICIPANTS: 1018 patients with locally advanced or metastatic cancer, no longer being treated for cancer, and recently referred to palliative care services. MAIN OUTCOME MEASURES: Performance of a composite model to predict whether patients were likely to survive for "days" (0-13 days), "weeks" (14-55 days), or "months+" (>55 days), compared with actual survival and clinicians' predictions. RESULTS: On multivariate analysis, 11 core variables (pulse rate, general health status, mental test score, performance status, presence of anorexia, presence of any site of metastatic disease, presence of liver metastases, C reactive protein, white blood count, platelet count, and urea) independently predicted both two week and two month survival. Four variables had prognostic significance only for two week survival (dyspnoea, dysphagia, bone metastases, and alanine transaminase), and eight variables had prognostic significance only for two month survival (primary breast cancer, male genital cancer, tiredness, loss of weight, lymphocyte count, neutrophil count, alkaline phosphatase, and albumin). Separate prognostic models were created for patients without (PiPS-A) or with (PiPS-B) blood results. The area under the curve for all models varied between 0.79 and 0.86. Absolute agreement between actual survival and PiPS predictions was 57.3% (after correction for over-optimism). The median survival across the PiPS-A categories was 5, 33, and 92 days and survival across PiPS-B categories was 7, 32, and 100.5 days. All models performed as well as, or better than, clinicians' estimates of survival. CONCLUSIONS: In patients with advanced cancer no longer being treated, a combination of clinical and laboratory variables can reliably predict two week and two month survival

    Cyclic changes in cortisol across the estrous cycle in parous and nulliparous Asian elephants

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     In the context of reproduction, glucocorticoids (GCs) are generally considered to have negative effects. However, in well-studied model species, GCs fluctuate predictability across the estrous cycles, and short-term increases promote healthy ovarian function. Reproductive challenges have plagued captive elephant populations, which are not currently self-sustaining. Efforts to understand reproductive dysfunction in elephants have focused on the suppressive effects of cortisol, but the potential permissive or stimulatory effects of cortisol are unknown. In this study, we provide a detailed examination of cortisol patterns across the estrous cycle in Asian elephants (Elephas maximus). Time series analysis was used to analyze cortisol and progesterone data for a total of 73 cycles from eight females. We also compared cortisol profiles between females that successfully conceived and females that failed to conceive despite repeated mating attempts. Our results revealed that cortisol fluctuates predictably across the estrous cycle, with a peak during the second half of the follicular phase followed by low levels throughout the luteal phase. Furthermore, this pattern was significantly altered in nulliparous females; cortisol concentrations did not decline during the luteal phase to the same extent as in parous females. This study highlights the complexity of cortisol signaling and suggests future directions for understanding the role of cortisol in reproductive dysfunction

    Evidence for transfer followed by breakup in 7Li + 65Cu

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    The observation of a large cross-section for the alpha + d channel compared to breakup into the alpha + t channel from an exclusive measurement for the 7Li+65Cu system at 25 MeV is presented. A detailed analysis of the angular distribution using coupled channels Born approximation calculations has provided clear evidence that the observed alpha + d events arise from a two step process, i.e. direct transfer to the 2.186 MeV (3+) resonance in the alpha + d continuum of 6Li followed by breakup, and are not due to final state interaction effects.Comment: 12 pages, 3 figures, To be published in Phys. Letts.

    Complete genome assemblies of three highly prevalent, toxigenic clostridioides difficile strains causing health care-associated infections in Australia

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    Clostridioides difficile infection (CDI) is the leading cause of life-threatening health care-related gastrointestinal illness worldwide. Phylogenetically appropriate closed reference genomes are essential for studies of C. difficile transmission and evolution. Here, we provide high-quality complete hybrid genome assemblies for the three most prevalent C. difficile strains causing CDI in Australia

    Determining Model-independent H0H_0 and Consistency Tests

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    We determine the Hubble constant H0H_0 precisely (2.3%2.3\% uncertainty) in a manner independent of cosmological model through Gaussian process regression, using strong lensing and supernova data. Strong gravitational lensing of a variable source can provide a time-delay distance DΔtD_{\Delta t} and angular diameter distance to the lens DdD_{\rm{d}}. These absolute distances can anchor Type Ia supernovae, which give an excellent constraint on the shape of the distance-redshift relation. Updating our previous results to use the H0LiCOW program's milestone dataset consisting of six lenses, four of which have both DΔtD_{\Delta t} and DdD_{\rm{d}} measurements, we obtain H0=72.81.7+1.6 km/s/MpcH_0=72.8_{-1.7}^{+1.6}\rm{\ km/s/Mpc} for a flat universe and H0=77.33.0+2.2 km/s/MpcH_0=77.3_{-3.0}^{+2.2}\rm{\ km/s/Mpc} for a non-flat universe. We carry out several consistency checks on the data and find no statistically significant tensions, though a noticeable redshift dependence persists in a particular systematic manner that we investigate. Speculating on the possibility that this trend of derived Hubble constant with lens distance is physical, we show how this can arise through modified gravity light propagation, which would also impact the weak lensing σ8\sigma_8 tension.Comment: 9 pages, 6 figures, 3 tables, title rephrase
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