Ultra Long Period Cepheids: a primary standard candle out to the Hubble flow

The cosmological distance ladder crucially depends on classical Cepheids (with P=3-80 days), which are primary distance indicators up to 33 Mpc. Within this volume, very few SNe Ia have been calibrated through classical Cepheids, with uncertainty related to the non-linearity and the metallicity dependence of their period-luminosity (PL) relation. Although a general consensus on these effects is still not achieved, classical Cepheids remain the most used primary distance indicators. A possible extension of these standard candles to further distances would be important. In this context, a very promising new tool is represented by the ultra-long period (ULP) Cepheids (P \geq 80 days), recently identified in star-forming galaxies. Only a small number of ULP Cepheids have been discovered so far. Here we present and analyse the properties of an updated sample of 37 ULP Cepheids observed in galaxies within a very large metallicity range of 12+log(O/H) from ~7.2 to 9.2 dex. We find that their location in the colour(V-I)-magnitude diagram as well as their Wesenheit (V-I) index-period (WP) relation suggests that they are the counterparts at high luminosity of the shorter-period (P \leq 80 days) classical Cepheids. However, a complete pulsation and evolutionary theoretical scenario is needed to properly interpret the true nature of these objects. We do not confirm the flattening in the studied WP relation suggested by Bird et al. (2009). Using the whole sample, we find that ULP Cepheids lie around a relation similar to that of the LMC, although with a large spread (~0.4 mag).Comment: 8 pages, 4 figures, accepted for publication in Astrophysics & Space Scienc

Morbidity associated with "self-rated health" in epithelial ovarian cancer survivors

<p>Abstract</p> <p>Background</p> <p>Epithelial ovarian cancer survivors (EOCSs) frequently report multiple complaints after their treatment. The objective was to study somatic and mental morbidity in EOCSs associated with their Self- Rated Health (SRH) assessed by a single item.</p> <p>Findings were compared to age-matched controls from the general population.</p> <p>Methods</p> <p>In a cross -sectional follow-up design 189/287 (66%) EOCSs treated at The Norwegian Radiumhospital 1979–2003 responded to a mailed questionnaire on demographic data, and somatic and mental morbidity. SRH last week was rated on item #29 of the European Organization and Treatment of Cancer Quality of Life Questionnaire in 84/189 (97%) of responding EOCSs. For comparisons "good" and "poor" SRH groups were defined by the median score on the SRH item.</p> <p>Results</p> <p>EOCSs with "poor SRH" had higher level of somatic symptoms, anxiety, depression and fatigue than those with "good SRH" (p < .001). In multivariate analyses somatic symptoms, age and fatigue, were significantly associated with the SRH score in EOCSs, but not the cancer-related variables (FIGO stage, recurrence in < 6 months or chemotherapy ever). The model explained 70% of the variance in SRH in linear and 77% in logistic regression analyses. The distribution of the SRH scores in EOCSs did not differ significantly from that of normative controls; however a higher proportion of controls recorded a high SRH score.</p> <p>Conclusion</p> <p>SRH is strongly related to common somatic complaints, impairment and fatigue but not to cancer-related variables. A single question concerning SRH last week might be a quick screening method for collecting important information on symptoms in EOCSs, in addition to cancer – related questions.</p

Impact of Tai Chi exercise on multiple fracture-related risk factors in post-menopausal osteopenic women: a pilot pragmatic, randomized trial

Background: Tai Chi (TC) is a mind-body exercise that shows potential as an effective and safe intervention for preventing fall-related fractures in the elderly. Few randomized trials have simultaneously evaluated TC's potential to reduce bone loss and improve fall-predictive balance parameters in osteopenic women. Methods: In a pragmatic randomized trial, 86 post-menopausal osteopenic women, aged 45-70, were recruited from community clinics. Women were assigned to either nine months of TC training plus usual care (UC) vs. UC alone. Primary outcomes were changes between baseline and nine months of bone mineral density (BMD) of the proximal femur and lumbar spine (dual-energy X-ray absorptiometry) and serum markers of bone resorption and formation. Secondary outcomes included quality of life. In a subsample (n = 16), quiet standing fall-predictive sway parameters and clinical balance tests were also assessed. Both intent-to-treat and per-protocol analyses were employed. Results: For BMD, no intent-to-treat analyses were statistically significant; however, per protocol analyses (i.e., only including TC participants who completed $\geq$ 75% training requirements) of femoral neck BMD changes were significantly different between TC and UC (+0.04 vs. -0.98%; P = 0.05). Changes in bone formation markers and physical domains of quality of life were also more favorable in per protocol TC vs. UC (P = 0.05). Changes in sway parameters were significantly improved by TC vs. UC (average sway velocity, P = 0.027; anterior-posterior sway range, P = 0.014). Clinical measures of balance and function showed non-significant trends in favor of TC. Conclusions: TC training offered through existing community-based programs is a safe, feasible, and promising intervention for reducing multiple fracture risks. Our results affirm the value of a more definitive, longer-term trial of TC for osteopenic women, adequately powered to detect clinically relevant effects of TC on attenuation of BMD loss and reduction of fall risk in this population

Exploring new physics frontiers through numerical relativity

The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

Relativistic Binaries in Globular Clusters

Galactic globular clusters are old, dense star systems typically containing 10\super{4}--10\super{7} stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of hard binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct {\it N}-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.Comment: 88 pages, 13 figures. Submitted update of Living Reviews articl

Star clusters near and far; tracing star formation across cosmic time

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio

High-resolution Doppler images of the spotted contact binary AE Phe

We present Doppler images of the short period (P = 0.362 d) W UMa binary AE Phe. In order to obtain the necessary S/N ratio and time resolution required to see individual star-spot features in highly rotationally broadened profiles, we use least-squares deconvolution, which makes use of the information content of the several thousand lines in a typical echelle spectrum. This yields a single rotation profile (free of sidelobes due to blending) per spectrum with a typical S/N ratio of several thousand.We use radial velocity curves, generated from standard profile fitting techniques, to measure velocity amplitudes and the mass ratio. Failure to model star-spots with this method leads to a biased set of values, and we show that an imaging code is essential if accurate system parameters are to be derived.Images are reconstructed from four nights of data which reveal star-spots at most latitudes on both components of the common envelope system. Our model requires that the primary component be several hundred K cooler than the secondary in order to reproduce the profile depth changes with phase. In a two-temperature imaging model, we interpret this as being due to 27 per cent greater - but unresolved - spot filling on the primary relative to the secondary component. The images reveal that dark spots are present on both stars at various latitudes and longitudes. Star-spots are also found in the neck region of both components, which appear to be darker on the side of each star leading in rotation phase - particularly on the secondary component. We investigate the reproducibility of the images from night to night and conclude that the star-spots evolve significantly on very short time-scales, of the order of 1 d. This is significantly faster than the week time-scales found on active single stars and the Sun.</p