Changes in laboratory markers of thrombotic risk early in the first trimester of pregnancy may be linked to an increase in estradiol and progesterone

Background: Pregnant women are at increased risk of venous thrombosis compared to non-pregnant women. Epidemiological and laboratory data suggest that hypercoagulability begins in the first trimester but it is unknown exactly how early in pregnancy this develops. The mechanisms that result in a prothrombotic state may involve oestrogens and progestogens. Methods: Plasma samples were taken prior to conception and five times in early pregnancy, up to Day 59 gestation, from 22 women undergoing natural cycle in vitro fertilization, who subsequently gave birth at term following a normal pregnancy. Thrombin generation, free Protein S, Ddimer, Fibrinogen, factor VIII, estradiol and progesterone were measured. To counter inter-individual variability, the change in laboratory measurements between the pre-pregnant and pregnant state were measured over time. Results: Peak thrombin, Endogenous Thrombin Potential, Velocity Index and fibrinogen significantly increased, and free Protein S significantly decreased, from pre-pregnancy levels, by 32 days gestation. Ddimer and VIII significantly increased from pre-pregnancy levels by 59 days gestation. Estradiol significantly increased by Day 32 gestation with a non-significant increase of 67% by Day 24 gestation. Progesterone significantly increased by Day 32 gestation. Almost all laboratory markers of thrombosis correlated significantly with estradiol and progesterone. Conclusion: Our work is the first to demonstrate that the prothrombotic state develops very early in the first trimester. Laboratory markers of hypercoagulability correlate significantly with estradiol and progesterone suggesting these are linked to the prothrombotic state of pregnancy. Clinicians should consider commencing thromboprophylaxis early in the first trimester in women at high thrombotic risk

Polarimetric Properties of Flux-Ropes and Sheared Arcades in Coronal Prominence Cavities

The coronal magnetic field is the primary driver of solar dynamic events. Linear and circular polarization signals of certain infrared coronal emission lines contain information about the magnetic field, and to access this information, either a forward or an inversion method must be used. We study three coronal magnetic configurations that are applicable to polar-crown filament cavities by doing forward calculations to produce synthetic polarization data. We analyze these forward data to determine the distinguishing characteristics of each model. We conclude that it is possible to distinguish between cylindrical flux ropes, spheromak flux ropes, and sheared arcades using coronal polarization measurements. If one of these models is found to be consistent with observational measurements, it will mean positive identification of the magnetic morphology that surrounds certain quiescent filaments, which will lead to a greater understanding of how they form and why they erupt.Comment: 22 pages, 8 figures, Solar Physics topical issue: Coronal Magnetis

The influence of melt flux and crustal processing on Re–Os isotope systematics of ocean island basalts: Constraints from Galápagos

New rhenium–osmium data for high-MgO (>9 wt.%) basalts from the Galápagos Archipelago reveal a large variation in 187Os/188Os (0.1304 to 0.173), comparable with the range shown by primitive global ocean island basalts (OIBs). Basalts with the least radiogenic 187Os/188Os occur closest to the Galápagos plume stem: those in western Galápagos have low 187Os/188Os, moderate 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb and high 3He/4He whereas basalts in the south also have low 187Os/188Os but more radiogenic 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb and 3He/4He. Our new Os isotope data are consistent with the previously established spatial zonation of the common global isotopic mantle reservoir “C” and ancient recycled oceanic crust in the mantle plume beneath western and southern parts of Galápagos, respectively. Galápagos basalts with the most radiogenic 187Os/188Os (up to 0.1875) typically have moderate MgO (7–9 wt.%) and low Os (<50 pg g−1) but have contrastingly unenriched Sr, Nd and Pb isotope signatures. We interpret this decoupling of chalcophile and lithophile isotopic systems as due to assimilation of young Pacific lower crust during crystal fractionation. Mixing models show the assimilated crust must have higher contents of Re and Os, and more radiogenic 187Os/188Os (0.32), than previously proposed for oceanic gabbros. We suggest the inferred, exceptionally-high radiogenic 187Os of the Pacific crust may be localised and due to sulfides precipitated from hydrothermal systems established at the Galápagos Spreading Centre. High 187Os/188Os Galápagos basalts are found where plume material is being dispersed laterally away from the plume stem to the adjacent spreading centre (i.e. in central and NE parts of the archipelago). The extent to which crustal processing influences 187Os/188Os appears to be primarily controlled by melt flux: as distance from the stem of the Galápagos plume increases, the melt flux decreases and crustal assimilation becomes proportionally greater, accounting for co-variations in Os and 187Os/188Os. The Os concentration threshold below which the 187Os/188Os of Galápagos basalts are contaminated (100 pg g−1) is higher than the canonical value (<50 pg g−1) assumed for many other global OIBs (e.g. for Iceland, Grande Comore and Hawaii). This most likely reflects the low overall melt flux to the crust from the Galápagos plume, which has only a moderate excess temperature and buoyancy flux. Our findings have implications for the interpretation of 187Os/188Os ratios in other ocean island settings, especially those where large variations in 187Os/188Os have been linked to heterogeneity in mantle lithology or sulfide populations: the effect of crustal contamination on 187Os/188Os may be greater than previously recognised, particularly for basalts associated with weak, low melt flux mantle plumes, such as Tristan, Bouvet, Crozet and St Helena

Developing sustainable small-scale fisheries livelihoods in Indonesia: Trends, enabling and constraining factors, and future opportunities

Small-scale fisheries (SSF) provide crucial contributions to livelihoods, food and nutrition security, and the well-being of coastal communities worldwide. In Indonesia, 2.5 million households are involved in SSF production, yet these households are characterised by high poverty rates and vulnerability due to declining ecosystem health and climatic change. In this study we applied the Sustainable Livelihoods Framework to analyse the characteristics and immediate and longer-term outcomes of 20 SSF livelihood-focused intervention programs implemented in coastal communities across the Indonesian Archipelago over the last two decades. Projects covered a wide range of spatial scales, funding providers and key participants. Factors supporting positive program outcomes included application of inclusive and holistic approaches to sustainable livelihoods, implemented and supported over appropriate time frames; use of participatory capacity development methodologies and locally-situated project facilitators; and collaborative engagement with local government, non-government organisations and private-sector actors. However, it was impossible to identify evidenced successes from a longer-term sustainability perspective. Short project timeframes, absence of baseline or monitoring data, pressure for satisfactory reports to donors, and limited post-project evaluation, together with invisibility of women’s work and non-commercial exchanges, affected the adequacy of assessments. Given the lack of post-project assessment among projects studied, a thorough review of longer-term project impacts is recommended, guided by the Sustainable Livelihoods Framework, to evaluate sustained improvements in livelihoods outcomes and environmental sustainability. This would support best-practice design and implementation of SSF livelihood-focused interventions, disseminated beyond academia, to influence policy and development to achieve socio-economic equity and environmental goals

Stochastic Variational Search for ΛΛ4^{4}_{\Lambda\Lambda}H

A four-body calculation of the $pn\Lambda\Lambda$ bound state, $^{\ 4}_{\Lambda\Lambda}$H, is performed using the stochastic variational method and phenomenological potentials. The$NN$,$\Lambda N$, and$\Lambda\Lambda$potentials are taken from a recent Letter by Filikhin and Gal, PRL{\bf 89}, 172502 (2002). Although their Faddeev-Yakubovsky calculation found no bound-state solution over a wide range of$\Lambda\Lambda$interaction strengths, the present variational calculation gives a bound-state energy, which is clearly lower than the$_\Lambda^3{H}+\Lambda$threshold, even for a weak$\Lambda\Lambda$interaction strength deduced from a recent experimental$B_{\Lambda\Lambda}(^{6}_{\Lambda\Lambda}{He})$value. The binding energies obtained are close to, and slightly larger than, the values obtained from the three-body$d\Lambda\Lambda$ model in the Letter.Comment: Corrected typos, added addtional calculations regarding a truncated to l=0 interaction model, 4 pages, 3 figure

On the structure and evolution of a polar crown prominence/filament system

Polar crown prominences are made of chromospheric plasma partially circling the Suns poles between 60 and 70 degree latitude. We aim to diagnose the 3D dynamics of a polar crown prominence using high cadence EUV images from the Solar Dynamics Observatory (SDO)/AIA at 304 and 171A and the Ahead spacecraft of the Solar Terrestrial Relations Observatory (STEREO-A)/EUVI at 195A. Using time series across specific structures we compare flows across the disk in 195A with the prominence dynamics seen on the limb. The densest prominence material forms vertical columns which are separated by many tens of Mm and connected by dynamic bridges of plasma that are clearly visible in 304/171A two-color images. We also observe intermittent but repetitious flows with velocity 15 km/s in the prominence that appear to be associated with EUV bright points on the solar disk. The boundary between the prominence and the overlying cavity appears as a sharp edge. We discuss the structure of the coronal cavity seen both above and around the prominence. SDO/HMI and GONG magnetograms are used to infer the underlying magnetic topology. The evolution and structure of the prominence with respect to the magnetic field seems to agree with the filament linkage model.Comment: 24 pages, 14 figures, Accepted for publication in Solar Physics Journal, Movies can be found at http://www2.mps.mpg.de/data/outgoing/panesar

Investigating event-specific drought attribution using self-organizing maps

Previous studies evaluating anthropogenic influences on the meteorological drivers of drought have found mixed results owing to (1) the complex physical mechanisms which lead to the onset of drought, (2) differences in the characteristics and time scales of drought for different regions of the world, and (3) different approaches to the question of attribution. For a midlatitude, temperate climate like New Zealand, strongly modulated by oceanic influences, summer droughts last on the order of 3 months, and are less strongly linked to persistent temperature anomalies than continental climates. Here we demonstrate the utility of a novel approach for characterizing the meteorological conditions conducive to extreme drought over the North Island of New Zealand, using the January–March 2013 event as a case study. Specifically, we consider the use of self‐organizing map techniques in a multimember coupled climate model ensemble to capture changes in daily circulation, between two 41 year periods (1861–1901 and 1993–2033). Comparisons are made with seasonal pressure and precipitation indices. Our results demonstrate robust (>99% confidence) increases in the likelihood of observing circulation patterns like those of the 2013 drought in the recent‐climate simulations when compared with the early‐climate simulations. Best guess estimates of the fraction of attributable risk range from 0.2 to 0.4, depending on the metric used and threshold considered. Contributions to uncertainty in these attribution statements are discussed

A spectrum of physics-informed Gaussian processes for regression in engineering

Despite the growing availability of sensing and data in general, we remain unable to fully characterize many in-service engineering systems and structures from a purely data-driven approach. The vast data and resources available to capture human activity are unmatched in our engineered world, and, even in cases where data could be referred to as “big,” they will rarely hold information across operational windows or life spans. This paper pursues the combination of machine learning technology and physics-based reasoning to enhance our ability to make predictive models with limited data. By explicitly linking the physics-based view of stochastic processes with a data-based regression approach, a derivation path for a spectrum of possible Gaussian process models is introduced and used to highlight how and where different levels of expert knowledge of a system is likely best exploited. Each of the models highlighted in the spectrum have been explored in different ways across communities; novel examples in a structural assessment context here demonstrate how these approaches can significantly reduce reliance on expensive data collection. The increased interpretability of the models shown is another important consideration and benefit in this context