5,915 research outputs found

    The prevalence of uterine fundal pressure during the second stage of labour for women giving birth in health facilities: a systematic review and meta-analysis.

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    Background Uterine fundal pressure involves a birth attendant pushing on the woman’s uterine fundus to assist vaginal birth. It is used in some clinical settings, though guidelines recommend against it. This systematic review aimed to determine the prevalence of uterine fundal pressure during the second stage of labour for women giving birth vaginally at health facilities. Methods The population of interest were women who experienced labour in a health facility and in whom vaginal birth was anticipated. The primary outcome was the use of fundal pressure during second stage of labour. MEDLINE, EMBASE, CINAHL and Global Index Medicus databases were searched for eligible studies published from 1 January 2000 onwards. Meta-analysis was conducted to determine a pooled prevalence, with subgroup analyses to explore heterogeneity. Results Eighty data sets from 76 studies (n = 898,544 women) were included, reporting data from 22 countries. The prevalence of fundal pressure ranged from 0.6% to 69.2% between studies, with a pooled prevalence of 23.2% (95% CI 19.4–27.0, I2 = 99.97%). There were significant differences in prevalence between country income level (p < 0.001, prevalence highest in lower-middle income countries) and method of measuring use of fundal pressure (p = 0.001, prevalence highest in studies that measured fundal pressure based on women’s self-report). Conclusions The use of uterine fundal pressure on women during vaginal birth in health facilities is widespread. Efforts to prevent this potentially unnecessary and harmful practice are needed

    Multiplicity of Galactic Cepheids from long-baseline interferometry I. CHARA/MIRC detection of the companion of V1334 Cygni

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    We aim at determining the masses of Cepheids in binary systems, as well as their geometric distances and the flux contribution of the companions. The combination of interferometry with spectroscopy will offer a unique and independent estimate of the Cepheid masses. Using long-baseline interferometry at visible and infrared wavelengths, it is possible to spatially resolve binary systems containing a Cepheid down to milliarcsecond separations. Based on the resulting visual orbit and radial velocities, we can then derive the fundamental parameters of these systems, particularly the masses of the components and the geometric distance. We therefore performed interferometric observations of the first-overtone mode Cepheid V1334 Cyg with the CHARA/MIRC combiner. We report the first detection of a Cepheid companion using long-baseline interferometry. We detect the signature of a companion orbiting V1334 Cyg at two epochs. We measure a flux ratio between the companion and the Cepheid f = 3.10+/-0.08%, giving an apparent magnitude mH = 8.47+/-0.15mag. The combination of interferometric and spectroscopic data have enabled the unique determination of the orbital elements: P = 1938.6+/-1.2 days, Tp = 2 443 616.1+/-7.3, a = 8.54+/-0.51mas, i = 124.7+/-1.8{\deg}, e = 0.190+/-0.013, {\omega} = 228.7+/-1.6{\deg}, and {\Omega} = 206.3+/-9.4{\deg}. We derive a minimal distance d ~ 691 pc, a minimum mass for both stars of 3.6 Msol, with a spectral type earlier than B5.5V for the companion star. Our measured flux ratio suggests that radial velocity detection of the companion using spectroscopy is within reach, and would provide an orbital parallax and model-free masses.Comment: Published in A&

    Imaging the Algol Triple System in H Band with the CHARA Interferometer

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    Algol (Beta Per) is an extensively studied hierarchical triple system whose inner pair is a prototype semi-detached binary with mass transfer occurring from the sub-giant secondary to the main-sequence primary. We present here the results of our Algol observations made between 2006 and 2010 at the CHARA interferometer with the Michigan Infrared Combiner in the H band. The use of four telescopes with long baselines allows us to achieve better than 0.5 mas resolution and to unambiguously resolve the three stars. The inner and outer orbital elements, as well as the angular sizes and mass ratios for the three components are determined independently from previous studies. We report a significantly improved orbit for the inner stellar pair with the consequence of a 15% change in the primary mass compared to previous studies. We also determine the mutual inclination of the orbits to be much closer to perpendicularity than previously established. State-of-the-art image reconstruction algorithms are used to image the full triple system. In particular an image sequence of 55 distinct phases of the inner pair orbit is reconstructed, clearly showing the Roche-lobe-filling secondary revolving around the primary, with several epochs corresponding to the primary and secondary eclipses

    The Ages of A-Stars I: Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group

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    We have observed and spatially resolved a set of seven A-type stars in the nearby Ursa Major moving group with the Classic, CLIMB, and PAVO beam combiners on the CHARA Array. At least four of these stars have large rotational velocities (vsiniv \sin i \gtrsim 170 km s1\mathrm{km~s^{-1}}) and are expected to be oblate. These interferometric measurements, the stars' observed photometric energy distributions, and vsiniv \sin i values are used to computationally construct model oblate stars from which stellar properties (inclination, rotational velocity, and the radius and effective temperature as a function of latitude, etc.) are determined. The results are compared with MESA stellar evolution models (Paxton et al. 2011, 2013) to determine masses and ages. The value of this new technique is that it enables the estimation of the fundamental properties of rapidly rotating stars without the need to fully image the star. It can thus be applied to stars with sizes comparable to the interferometric resolution limit as opposed to those that are several times larger than the limit. Under the assumption of coevality, the spread in ages can be used as a test of both the prescription presented here and the MESA evolutionary code for rapidly rotating stars. With our validated technique, we combine these age estimates and determine the age of the moving group to be 414 ±\pm 23 Myr, which is consistent with, but much more precise than previous estimates.Comment: Accepted by Ap

    Clinical guidelines for caring for women with COVID-19 during pregnancy, childbirth and the immediate postpartum period.

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    BACKGROUND:The spread of the novel coronavirus (COVID-19) was declared a pandemic by the World Health Organization on 11th March 2020. Since then there has been a rapid rise in development of maternal and perinatal health guidelines related to COVID-19. The aim of this project was to develop a database of Australian and international recommendations relating to antenatal, intrapartum and postpartum care of women during the COVID-19 pandemic, in order to identify inconsistencies in clinical guidance. METHODS:We conducted weekly web searches from 30th March to 15th May 2020 to identify recommendations pertaining to the care of women during pregnancy, labour and postpartum period from national or international professional societies, specialist colleges, Ministries of Health, Australian state and territory governments, and international guideline development organisations. Individual recommendations were extracted and classified according to intervention type, time period, and patient population. Findings were reported using descriptive analysis, with areas of consensus and non-consensus identified. RESULTS:We identified 81 guidelines from 48 different organisations. Generally, there was high consensus across guidelines for specific interventions. However, variable guidance was identified on the use of nitrous oxide during labour, administration of antenatal corticosteroids, neonatal isolation after birth, labour and birth companions, and the use of disease modifying agents for treating COVID-19. CONCLUSION:Discrepancies between different guideline development organisations creates challenges for maternity care clinicians during the COVID-19 pandemic. Collating recommendations and keeping up-to-date with the latest guidance can help clinicians provide the best possible care to pregnant women and their babies

    Angular Diameters of the G Subdwarf μ\mu Cassiopeiae A and the K Dwarfs σ\sigma Draconis and HR 511 from Interferometric Measurements with the CHARA Array

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    Using the longest baselines of the CHARA Array, we have measured the angular diameter of the G5 V subdwarf μ\mu Cas A, the first such determination for a halo population star. We compare this result to new diameters for the higher metallicity K0 V stars, σ\sigma Dra and HR 511, and find that the metal-poor star, μ\mu Cas A, has an effective temperature (Teff=5297±32T_{\rm eff}=5297\pm32 K), radius (R=0.791±0.008RR=0.791\pm0.008 R_{\rm \odot}), and absolute luminosity (L=0.442±0.014LL=0.442\pm0.014 L_{\rm \odot}) comparable to the other two stars with later spectral types. We show that stellar models show a discrepancy in the predicted temperature and radius for μ\mu Cas A, and we discuss these results and how they provide a key to understanding the fundamental relationships for stars with low metallicity.Comment: Accepted for publication in The Astrophysical Journa

    'Digital by Default' and the 'hard to reach': Exploring solutions to digital exclusion in remote rural areas

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    Williams, F., Philip, L., Fairhurst, G., & Farrington, J. (2016). ‘Digital by Default’ and ‘the hard to reach’: exploring solutions to digital exclusion in remote rural areas. Local Economy, 31(7), 757-777. DOI: 10.1177/0269094216670938. Copyright © 2016 SAGE. Reprinted by permission of SAGE Publications.In the UK, the geography of Information and Communication Technology (ICT) infrastructure required for Internet connectivity is such that high speed broadband and mobile phone networks are generally less available in rural areas compared with urban areas or, in other words, as remoteness and population sparsity increase so too does the likelihood of an area having no or very poor broadband connectivity. Against a policy backdrop of UK Government efforts to bring forward network infrastructure upgrades and to improve the accessibility of broadband services in locations where there is a weak commercial investment case, this paper considers the options for the ‘final few’ in the prevailing ‘Digital by Default’ public services context. The paper outlines the Rural Public Access WiFi Services project, a study focused upon enabling Internet connectivity for commercially ‘hard to reach’ rural areas in the UK. The Rural Public Access WiFi Services concept and the experiment are introduced before findings from a pilot deployment of a broadband service to households in a remote rural area, who may be classified as ‘digitally excluded’, are presented. The paper then reflects on our field experiment and the potential of the Rural Public Access WiFi Services model as a solution to overcoming some of the digital participation barriers manifest in the urban–rural divide. Early indications show that the Rural Public Access WiFi Services model has the potential to encourage participation in the Digital Economy and could aid the UK Government’s Digital by Default agenda, although adoption of the model is not without its challenges

    Toward Direct Detection of Hot Jupiters with Precision Closure Phase: Calibration Studies and First Results from the CHARA Array

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    Direct detection of thermal emission from nearby hot Jupiters has greatly advanced our knowledge of extrasolar planets in recent years. Since hot Jupiter systems can be regarded as analogs of high contrast binaries, ground-based infrared long baseline interferometers have the potential to resolve them and detect their thermal emission with precision closure phase - a method that is immune to the systematic errors induced by the Earth's atmosphere. In this work, we present closure phase studies toward direct detection of nearby hot Jupiters using the CHARA interferometer array outfitted with the MIRC instrument. We carry out closure phase simulations and conduct a large number of observations for the best candidate {\upsion} And. Our experiments suggest the method is feasible with highly stable and precise closure phases. However, we also find much larger systematic errors than expected in the observations, most likely caused by dispersion across different wavelengths. We find that using higher spectral resolution modes (e.g., R=150) can significantly reduce the systematics. By combining all calibrators in an observing run together, we are able to roughly recalibrate the lower spectral resolution data, allowing us to obtain upper limits of the star-planet contrast ratios of {\upsion} And b across the H band. The data also allow us to get a refined stellar radius of 1.625\pm0.011 R\odot. Our best upper limit corresponds to a contrast ratio of 2.1\times10^3:1 with 90% confidence level at 1.52{\mu}m, suggesting that we are starting to have the capability of constraining atmospheric models of hot Jupiters with interferometry. With recent and upcoming improvements of CHARA/MIRC, the prospect of detecting emission from hot Jupiters with closure phases is promising.Comment: 30 pages, including 9 figures and 4 tables. Published in PASP in August 201
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