189 research outputs found
Intergenerational Associations of Chronic Disease and Polycystic Ovary Syndrome
Extent: 4p.Background: Polycystic ovary syndrome (PCOS) is a common female endocrine disorder of heterogeneous clinical presentation, high disease burden, and unknown aetiology. The disease and associated conditions cluster in families, suggesting that PCOS may be the reproductive consequence of underlying chronic disease susceptibility. Objective: To determine whether parents of young women with PCOS were more likely to have a history of diabetes or cardiovascular disease in later adult life. Design, Setting and Participants: Structured interviews with 715 members of a cohort constructed by tracing female infants born at a single general hospital in Adelaide between 1973 and 1975. Participants were asked whether they had a pre-existing medical diagnosis of PCOS, and whether each parent had ever had high blood pressure, high cholesterol, diabetes, stroke, or heart disease. Maternal high blood pressure during pregnancy was taken from the medical record of the pregnancy with the study participant. Results and Conclusions: Mothers of women with PCOS were more likely than mothers of other women to have any cardiovascular disease (RR 1.78, 95% CI 1.29, 2.47), and nearly twice as likely to have high blood pressure (RR 1.95, 95% CI 1.38, 2.76). Fathers of women with PCOS were more than twice as likely to have heart disease (RR 2.36, 95% CI 1.44, 3.88) and over four times as likely to have had a stroke (RR 4.37, 95% CI 1.97, 9.70). Occurrence of cardiovascular disease in both mother and father are associated with the risk of PCOS in daughters. Further detailed study is required to elucidate the precise pathways that may be causally related to the observations.Michael J. Davies, Jennifer L. Marino, Kristyn J. Willson, Wendy A. March and Vivienne M. Moor
Chemical evolution of local post-starburst galaxies: Implications for the mass-metallicity relation
We use the stellar fossil record to constrain the stellar metallicity
evolution and star-formation histories of the post-starburst regions within 45
local post-starburst galaxies from the MaNGA survey. The direct measurement of
the regions' stellar metallicity evolution is achieved by a new two-step
metallicity model that allows for stellar metallicity to change at the peak of
the starburst. We also employ a Gaussian process noise model that accounts for
correlated errors introduced by the observational data reduction or
inaccuracies in the models. We find that a majority of post-starburst regions
(69% at significance) increased in stellar metallicity during the
recent starburst, with an average increase of 0.8 dex and a standard deviation
of 0.4 dex. A much smaller fraction of PSBs are found to have remained constant
(22%) or declined in metallicity (9%, average decrease 0.4 dex, standard
deviation 0.3 dex). The pre-burst metallicities of the post-starburst galaxies
are in good agreement with the mass-metallicity relation of local star-forming
galaxies. These results are consistent with hydrodynamic simulations, which
suggest that mergers between gas-rich galaxies are the primary formation
mechanism of local PSBs, and rapid metal recycling during the starburst
outweighs the impact of dilution by any gas inflows. The final mass-weighted
metallicities of the post-starburst galaxies are consistent with the
mass-metallicity relation of local passive galaxies. Our results suggest that
rapid quenching following a merger-driven starburst is entirely consistent with
the observed gap between the stellar mass-metallicity relations of local
star-forming and passive galaxies.Comment: 18+4 pages, 8+2 figures, submitted to MNRA
Chemical evolution of local post-starburst galaxies : implications for the mass-metallicity relation
We use the stellar fossil record to constrain the stellar metallicity evolution and star-formation histories of the post-starburst (PSB) regions within 45 local PSB galaxies from the MaNGA survey. The direct measurement of the regionsâ stellar metallicity evolution is achieved by a new two-step metallicity model that allows for stellar metallicity to change at the peak of the starburst. We also employ a Gaussian process noise model that accounts for correlated errors introduced by the observational data reduction or inaccuracies in the models. We find that a majority of PSB regions (69 perâcent at >1Ï significance) increased in stellar metallicity during the recent starburst, with an average increase of 0.8 dex and a standard deviation of 0.4 dex. A much smaller fraction of PSBs are found to have remained constant (22 perâcent) or declined in metallicity (9 perâcent, average decrease 0.4 dex, standard deviation 0.3 dex). The pre-burst metallicities of the PSB galaxies are in good agreement with the massâmetallicity (MZ) relation of local star-forming galaxies. These results are consistent with hydrodynamic simulations, which suggest that mergers between gas-rich galaxies are the primary formation mechanism of local PSBs, and rapid metal recycling during the starburst outweighs the impact of dilution by any gas inflows. The final mass-weighted metallicities of the PSB galaxies are consistent with the MZ relation of local passive galaxies. Our results suggest that rapid quenching following a merger-driven starburst is entirely consistent with the observed gap between the stellar massâmetallicity relations of local star-forming and passive galaxies.Peer reviewe
What happens after an NHS Health Check? A survey and realist review
Background The National Health Service Health Check in England aims to provide adults aged 40 to 74 with an assessment of their risk of developing cardiovascular disease and to offer advice to help manage and reduce this risk. The programme is commissioned by local authorities and delivered by a range of providers in different settings, although primarily in general practices. This project focused on variation in the advice, onward referrals and prescriptions offered to attendees following their health check. Objectives (1) Map recent programme delivery across England via a survey of local authorities; (2) conduct a realist review to enable understanding of how the National Health Service Health Check programme works in different settings, for different groups; (3) provide recommendations to improve delivery. Design Survey of local authorities and realist review of the literature. Review methods Realist review is a theory-driven, interpretive approach to evidence synthesis that seeks to explain why, when and for whom outcomes occur. We gathered published research and grey literature (including local evaluation documents and conference materials) via searching and supplementary methods. Extracted data were synthesised using a realist logic of analysis to develop an understanding of important contexts that affect the delivery of National Health Service Health Checks, and underlying mechanisms that produce outcomes related to our project focus. Results Our findings highlight the variation in National Health Service Health Check delivery models across England. Commissioners, providers and attendees understand the programmeâs purpose in different ways. When understood primarily as an opportunity to screen for disease, responsibility for delivery and outcomes rests with primary care, and there is an emphasis on volume of checks delivered, gathering essential data and communicating risk. When understood as an opportunity to prompt and support behaviour change, more emphasis is placed on delivery of advice and referrals to âlifestyle servicesâ. Practical constraints limit what can be delivered within the programmeâs remit. Public health funding restricts delivery options and links with onward services, while providers may struggle to deliver effective checks when faced with competing priorities. Attendeesâ responses to the programme are affected by features of delivery models and the constraints they face within their own lives. Limitations Survey response rate lower than anticipated; review findings limited by the availability and quality of the literature. Conclusions and implications The purpose and remit of the National Health Service Health Check programme should be clarified, considering prevailing attitudes about its value (especially among providers) and what can be delivered within existing resources. Some variation in delivery is likely to be appropriate to meet local population needs, but lack of clarity for the programme contributes to a âpostcode lotteryâ effect in the support offered to attendees after a check. Our findings raise important questions about whether the programme itself and services that it may feed into are adequately resourced to achieve positive outcomes for attendees, and whether current delivery models may produce inequitable outcomes. Future work Policy-makers and commissioners should consider the implications of the findings of this project; future research should address the relative scarcity of studies focused on the end of the National Health Service Health Check pathway
Galaxy And Mass Assembly (GAMA) : The mechanisms for quiescent galaxy formation at z<1
© 2016 The Authors. One key problem in astrophysics is understanding how and why galaxies switch off their star formation, building the quiescent population that we observe in the local Universe. From the Galaxy And Mass Assembly and VIsible MultiObject Spectrograph Public Extragalactic Redshift surveys, we use spectroscopic indices to select quiescent and candidate transition galaxies.We identify potentially rapidly transitioning post-starburst (PSB) galaxies and slower transitioning green-valley galaxies. Over the last 8Gyr, the quiescent population has grown more slowly in number density at high masses (M * > 10 11 M â ) than at intermediate masses (M * > 10 10.6 M â ). There is evolution in both the PSB and green-valley stellar mass functions, consistent with higher mass galaxies quenching at earlier cosmic times.At intermediatemasses (M * > 10 10.6 M â ), we find a green-valley transition time-scale of 2.6 Gyr. Alternatively, at z ~ 0.7, the entire growth rate could be explained by fast-quenching PSB galaxies, with a visibility time-scale of 0.5 Gyr. At lower redshift, the number density of PSBs is so low that an unphysically short visibility window would be required for them to contribute significantly to the quiescent population growth. The importance of the fast-quenching route may rapidly diminish at z 10 11 M â ), there is tension between the large number of candidate transition galaxies compared to the slow growth of the quiescent population. This could be resolved if not all high-mass PSB and green-valley galaxies are transitioning from star forming to quiescent, for example if they rejuvenate out of the quiescent population following the accretion of gas and triggering of star formation, or if they fail to completely quench their star formation
Evolution of system embedded optical interconnect in sub-top of rack data center systems
This research was funded by the EU FP7 project âPhoxTrotâ, for which it has received funding from the European Union Seventh Framework Programme (FP7/2007â2013) under grant agreement No. 318240, the Horizon2020 Nephele project (Grant No. 645212), the Horizon2020 COSMICC project (Grant No. 688516).In this paper we review key technological milestones in system embedded optical interconnects in data centers that have been achieved between 2014 and 2020 on major European Union research and development projects. This includes the development of proprietary optically enabled data storage and switch systems and optically enabled data storage and compute subsystems. We report on four optically enabled data center system demonstrators: LightningValley, ThunderValley2, Pegasus and Aurora, which include advanced optical circuits based on polymer waveguides and fibers and proprietary electro-optical connectors. We also report on optically enabled subsystems including Ethernet-connected hard disk drives and microservers. Both are designed in the same pluggable carrier form factor and with embedded optical transceiver and connector interfaces, thus allowing, for the first time, both compute and storage nodes to be optically interchangeable and directly interconnectable over long distances. Finally, we present the Nexus platform, which allows different optically enabled data center test systems and subsystems to be interconnected and comparatively characterized within a data center test environment.Publisher PDFPeer reviewe
Indicators of Intrinsic AGN Luminosity: a Multi-Wavelength Approach
We consider five indicators for intrinsic AGN luminosity: the luminosities of
the [OIII]5007 line, the [OIV]25.89m line, the mid-infrared (MIR)
continuum emission by the torus, and the radio and hard X-ray (E 10keV)
continuum emission. We compare these different proxies using two complete
samples of low-redshift type 2 AGN selected in a homogeneous way based on
different indicators: an optically selected [OIII] sample and a mid-infrared
selected 12m sample. We examine the correlations between all five
different proxies, and find better agreement for the [OIV], MIR, and [OIII]
luminosities than for the hard X-ray and radio luminosities. Next, we compare
the ratios of the fluxes of the different proxies to their values in unobscured
Type 1 AGN. The agreement is best for the ratio of the [OIV] and MIR fluxes,
while the ratios of the hard X-ray to [OIII], [OIV], and MIR fluxes are
systematically low by about an order-of-magnitude in the Type 2 AGN, indicating
that hard X-ray selected samples do not represent the full Type 2 AGN
population. In a similar spirit, we compare different optical and MIR
diagnostics of the relative energetic contributions of AGN and star formation
processes in our samples of Type 2 AGN. We find good agreement between the
various diagnostic parameters, such as the equivalent width of the MIR
polycyclic aromatic hydrocarbon features, the ratio of the MIR [OIV]/[NeII]
emission-lines, the spectral index of the MIR continuum, and the commonly used
optical emission-line ratios. Finally, we test whether the presence of cold gas
associated with star-formation leads to an enhanced conversion efficiency of
AGN ionizing radiation into [OIII] or [OIV] emission. We find that no
compelling evidence exists for this scenario for the luminosities represented
in this sample (L 10 - 8 10
L_{\sun}). (abridged)Comment: accepted for publication in ApJ; 58 page
The GALEX Arecibo SDSS Survey. I. Gas Fraction Scaling Relations of Massive Galaxies and First Data Release
We introduce the GALEX Arecibo SDSS Survey (GASS), an on-going large program
that is gathering high quality HI-line spectra using the Arecibo radio
telescope for an unbiased sample of ~1000 galaxies with stellar masses greater
than 10^10 Msun and redshifts 0.025<z<0.05, selected from the SDSS
spectroscopic and GALEX imaging surveys. The galaxies are observed until
detected or until a low gas mass fraction limit (1.5-5%) is reached. This paper
presents the first Data Release, consisting of ~20% of the final GASS sample.
We use this data set to explore the main scaling relations of HI gas fraction
with galaxy structure and NUV-r colour. A large fraction (~60%) of the galaxies
in our sample are detected in HI. We find that the atomic gas fraction
decreases strongly with stellar mass, stellar surface mass density and NUV-r
colour, but is only weakly correlated with galaxy bulge-to-disk ratio (as
measured by the concentration index of the r-band light). We also find that the
fraction of galaxies with significant (more than a few percent) HI decreases
sharply above a characteristic stellar surface mass density of 10^8.5 Msun
kpc^-2. The fraction of gas-rich galaxies decreases much more smoothly with
stellar mass. One of the key goals of GASS is to identify and quantify the
incidence of galaxies that are transitioning between the blue, star-forming
cloud and the red sequence of passively-evolving galaxies. Likely transition
candidates can be identified as outliers from the mean scaling relations
between gas fraction and other galaxy properties. [abridged]Comment: 25 pages, 12 figures. Accepted for publication in MNRAS. Version with
high resolution figures available at
http://www.mpa-garching.mpg.de/GASS/pubs.ph
Recommended from our members
Modeling Study of the Air Quality Impact of Record-Breaking Southern California Wildfires in December 2017
We investigate the air quality impact of recordâbreaking wildfires in Southern California during 5â18 December 2017 using the Weather Research and Forecasting model with Chemistry in combination with satellite and surface observations. This wildfire event was driven by dry and strong offshore Santa Ana winds, which played a critical role in fire formation and air pollutant transport. By utilizing fire emissions derived from the highâresolution (375 Ă 375 mÂČ) Visible Infrared Imaging Radiometer Suite active fire detections, the simulated magnitude and temporal evolution of fine particulate matter (PM_(2.5)) concentrations agree reasonably well with surface observations (normalized mean bias = 4.0%). Meanwhile, the model could generally capture the spatial pattern of aerosol optical depth from satellite observations. Sensitivity tests reveal that using a high spatial resolution for fire emissions and a reasonable treatment of plume rise (a fair split between emissions injected at surface and those lifted to upper levels) is important for achieving decent PM_(2.5) simulation results. Biases in PM_(2.5) simulation are relatively large (about 50%) during the period with the strongest Santa Ana wind, due to a possible underestimation of burning area and uncertainty in wind field variation. The 2017 December fire event increases the 14âday averaged PM_(2.5) concentrations by up to 231.2 ÎŒg/mÂł over the downwind regions, which substantially exceeds the U.S. air quality standards, potentially leading to adverse health impacts. The human exposure to fireâinduced PM_(2.5) accounts for 14â42% of the annual total PM_(2.5) exposure in areas impacted by the fire plumes
The GALEX Arecibo SDSS Survey II: The Star Formation Efficiency of Massive Galaxies
We use measurements of the HI content, stellar mass and star formation rates
in ~190 massive galaxies with stellar masses greater than 10^10 Msun, obtained
from the Galex Arecibo SDSS Survey (GASS) described in Paper I (Catinella et
al. 2010) to explore the global scaling relations associated with the
bin-averaged ratio of the star formation rate over the HI mass, which we call
the HI-based star formation efficiency (SFE). Unlike the mean specific star
formation rate, which decreases with stellar mass and stellar mass surface
density, the star formation efficiency remains relatively constant across the
sample with a value close to SFE = 10^-9.5 yr^-1 (or an equivalent gas
consumption timescale of ~3 Gyr). Specifically, we find little variation in SFE
with stellar mass, stellar mass surface density, NUV-r color and concentration.
We interpret these results as an indication that external processes or feedback
mechanisms that control the gas supply are important for regulating star
formation in massive galaxies. An investigation into the detailed distribution
of SFEs reveals that approximately 5% of the sample shows high efficiencies
with SFE > 10^-9 yr^-1, and we suggest that this is very likely due to a
deficiency of cold gas rather than an excess star formation rate. Conversely,
we also find a similar fraction of galaxies that appear to be gas-rich for
their given specific star-formation rate, although these galaxies show both a
higher than average gas fraction and lower than average specific star formation
rate. Both of these populations are plausible candidates for "transition"
galaxies, showing potential for a change (either decrease or increase) in their
specific star formation rate in the near future. We also find that 36+/-5% of
the total HI mass density and 47+/-5% of the total SFR density is found in
galaxies with stellar mass greater than 10^10 Msun. [abridged]Comment: 18 pages, 11 figures. Accepted for publication in MNRAS. GASS
publications and released data can be found at
http://www.mpa-garching.mpg.de/GASS/index.ph
- âŠ