Length scales, patterns and origin of azimuthal seismic anisotropy in the upper mantle as mapped by Rayleigh waves

We measure the degree of consistency between published models of azimuthal seismic anisotropy from surface waves, focusing on Rayleigh wave phase-velocity models. Some models agree up to wavelengths of ∼2000 km, albeit at small values of linear correlation coefficients. Others are, however, not well correlated at all, also with regard to isotropic structure. This points to differences in the underlying data sets and inversion strategies, particularly the relative ‘damping' of mapped isotropic versus anisotropic anomalies. Yet, there is more agreement between published models than commonly held, encouraging further analysis. Employing a generalized spherical harmonic representation, we analyse power spectra of orientational (2Ψ) anisotropic heterogeneity from seismology. We find that the anisotropic component of some models is characterized by stronger short-wavelength power than the associated isotropic structure. This spectral signal is consistent with predictions from new geodynamic models, based on olivine texturing in mantle flow. The flow models are also successful in predicting some of the seismologically mapped patterns. We substantiate earlier findings that flow computations significantly outperform models of fast azimuths based on absolute plate velocities. Moreover, further evidence for the importance of active upwellings and downwellings as inferred from seismic tomography is presented. Deterministic estimates of expected anisotropic structure based on mantle flow computations such as ours can help guide future seismologic inversions, particularly in oceanic plate regions. We propose to consider such a priori information when addressing open questions about the averaging properties and resolution of surface and body wave based estimates of anisotrop

Towards an expert consensus to delineate a clinical syndrome of chronic breathlessness

Copyright ©ERS 2017. Breathlessness that persists despite treatment for the underlying conditions is debilitating. Identifying this discrete entity as a clinical syndrome should raise awareness amongst patients, clinicians, service providers, researchers and research funders.Using the Delphi method, questions and statements were generated via expert group consultations and one-to-one interviews (n=17). These were subsequently circulated in three survey rounds (n=34, n=25, n=31) to an extended international group from various settings (clinical and laboratory; hospital, hospice and community) and working within the basic sciences and clinical specialties. The a priori target agreement for each question was 70%. Findings were discussed at a multinational workshop.The agreed term, chronic breathlessness syndrome, was defined as breathlessness that persists despite optimal treatment of the underlying pathophysiology and that results in disability. A stated duration was not needed for "chronic". Key terms for French and German translation were also discussed and the need for further consensus recognised, especially with regard to cultural and linguistic interpretation.We propose criteria for chronic breathlessness syndrome. Recognition is an important first step to address the therapeutic nihilism that has pervaded this neglected symptom and could empower patients and caregivers, improve clinical care, focus research, and encourage wider uptake of available and emerging evidence-based interventions

A pragmatic, phase III, multisite, double-blind, placebo-controlled, parallel-arm, dose increment randomised trial of regular, low-dose extended-release morphine for chronic breathlessness: Breathlessness, Exertion And Morphine Sulfate (BEAMS) study proto

© Article author(s). Introduction Chronic breathlessness is highly prevalent and distressing to patients and families. No medication is registered for its symptomatic reduction. The strongest evidence is for regular, low-dose, extended-release (ER) oral morphine. A recent large phase III study suggests the subgroup most likely to benefit have chronic obstructive pulmonary disease (COPD) and modified Medical Research Council breathlessness scores of 3 or 4. This protocol is for an adequately powered, parallel-Arm, placebo-controlled, multisite, factorial, block-randomised study evaluating regular ER morphine for chronic breathlessness in people with COPD. Methods and analysis The primary question is what effect regular ER morphine has on worst breathlessness, measured daily on a 0-10 numerical rating scale. Uniquely, the coprimary outcome will use a FitBit to measure habitual physical activity. Secondary questions include safety and, whether upward titration after initial benefit delivers greater net symptom reduction. Substudies include longitudinal driving simulation, sleep, caregiver, health economic and pharmacogenetic studies. Seventeen centres will recruit 171 participants from respiratory and palliative care. The study has five phases including three randomisation phases to increasing doses of ER morphine. All participants will receive placebo or active laxatives as appropriate. Appropriate statistical analysis of primary and secondary outcomes will be used. Ethics and dissemination Ethics approval has been obtained. Results of the study will be submitted for publication in peer-reviewed journals, findings presented at relevant conferences and potentially used to inform registration of ER morphine for chronic breathlessness. Trial registration number NCT02720822; Pre-results

Massive stars in the giant molecular cloud G23.3−0.3 and W41

Context. Young massive stars and stellar clusters continuously form in the Galactic disk, generating new Hii regions within their natal giant molecular clouds and subsequently enriching the interstellar medium via their winds and supernovae.Aims. Massive stars are among the brightest infrared stars in such regions; their identification permits the characterisation of the star formation history of the associated cloud as well as constraining the location of stellar aggregates and hence their occurrence as a function of global environment.Methods. We present a stellar spectroscopic survey in the direction of the giant molecular cloud G23.3−0.3. This complex is located at a distance of ~4–5 kpc, and consists of several Hii regions and supernova remnants.Results. We discovered 11 OfK+ stars, one candidate luminous blue variable, several OB stars, and candidate red supergiants. Stars with K-band extinction from ~1.3–1.9 mag appear to be associated with the GMC G23.3−0.3; O and B-types satisfying this criterion have spectrophotometric distances consistent with that of the giant molecular cloud. Combining near-IR spectroscopic and photometric data allowed us to characterize the multiple sites of star formation within it. The O-type stars have masses from ~25–45 M⊙, and ages of 5–8 Myr. Two new red supergiants were detected with interstellar extinction typical of the cloud; along with the two RSGs within the cluster GLIMPSE9, they trace an older burst with an age of 20–30 Myr. Massive stars were also detected in the core of three supernova remnants – W41, G22.7−0.2, and G22.7583−0.4917.Conclusions. A large population of massive stars appears associated with the GMC G23.3−0.3, with the properties inferred for them indicative of an extended history of stars formation

A new precise mass for the progenitor of the Type IIP SN 2008bk

The progenitor of the Type IIP SN 2008bk was discovered in pre-explosion g'r'i'IYJHKs images, acquired with European Southern Observatory Very Large Telescope FORS, HAWK-I and ISAAC instruments and the Gemini GMOS-S instrument. The wealth of pre-explosion observations makes the progenitor of this SN one of the best studied, since the detection of the progenitor of SN1987A. Previous analyses of the properties of the progenitor were hampered by the limited quality of the photometric calibration of the pre-explosion images and the crowded nature of the field containing the SN. We present new late-time observations of the site of SN2008bk acquired with identical instrument and filter configurations as the pre-explosion observations, and confirm that the previously identified red supergiant star was the progenitor of this SN and has now disappeared. Image subtraction techniques were used to conduct precise photometry of the now missing progenitor, independently of blending from any nearby stars. The nature of the surrounding stellar population and their contribution to the flux attributed to the progenitor in the pre-explosion images are probed using HST WFC3 UVIS/IR observations. In comparison with MARCS synthetic spectra, we find the progenitor was a highly reddened RSG with luminosity log (L/Lsun)=4.84+/-0.11, corresponding to an initial mass of Minit=12.9+/-1.7Msun. The temperature of the progenitor was hotter than previously expected for RSGs (T ~ 4330K), but consistent with new temperatures derived for RSGs using SED fitting techniques. We show that there is evidence for significant extinction of the progenitor, possibly arising in the CSM; but that this dust yields a similar reddening law to dust found in the ISM (E(B-V)=0.77 with Rv=3.1). [Abridged]Comment: 16 pages, 7 figures - submitted to MNRAS (21 July

Shear wave splitting at the Hawaiian hot spot from the PLUME land and ocean bottom seismometer deployments

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q02007, doi:10.1029/2011GC003881.We examine upper mantle anisotropy across the Hawaiian Swell by analyzing shear wave splitting of teleseismic SKS waves recorded by the PLUME broadband land and ocean bottom seismometer deployments. Mantle anisotropy beneath the oceans is often attributed to flow-induced lattice-preferred orientation of olivine. Splitting observations may reflect a combination of both fossil lithospheric anisotropy and anisotropy due to present-day asthenospheric flow, and here we address the question whether splitting provides diagnostic information on possible asthenospheric plume flow at Hawaii. We find that the splitting fast directions are coherent and predominantly parallel to the fossil spreading direction, suggesting that shear wave splitting dominantly reflects fossil lithospheric anisotropy. The signature of anisotropy from asthenospheric flow is more subtle, although it could add some perturbation to lithospheric splitting. The measured delay times are typically 1 s or less, although a few stations display larger splitting delays of 1–2 s. The variability in the delay times across the different stations indicates differences in the degree of anisotropy or in the thickness of the anisotropic layer or in the effect of multilayer anisotropy. Regions with smaller splitting times may have experienced processes that modified the lithosphere and partially erased the fossil anisotropy; alternatively, asthenospheric splitting may either constructively add to or destructively subtract from lithospheric splitting to produce the observed variability in delay times.The PLUME project was supported by NSF.2012-08-1

Research priorities to address the global burden of chronic obstructive pulmonary disease (COPD) in the next decade

Background The global prevalence of chronic obstructive pulmonary disease (COPD) has increased markedly in recent decades. Given the scarcity of resources available to address global health challenges and respiratory medicine being relatively under-invested in, it is important to define research priorities for COPD globally. In this paper, we aim to identify a ranked set of COPD research priorities that need to be addressed in the next 10 years to substantially reduce the global impact of COPD. Methods We adapted the Child Health and Nutrition Research Initiative (CHNRI) methodology to identify global COPD research priorities. Results 62 experts contributed 230 research ideas, which were scored by 34 researchers according to six pre-defined criteria: answerability, effectiveness, feasibility, deliverability, burden reduction, and equity. The top-ranked research priority was the need for new effective strategies to support smoking cessation. Of the top 20 overall research priorities, six were focused on feasible and cost-effective pulmonary rehabilitation delivery and access, particularly in primary/community care and low-resource settings. Three of the top 10 overall priorities called for research on improved screening and accurate diagnostic methods for COPD in low-resource primary care settings. Further ideas that drew support involved a better understanding of risk factors for COPD, development of effective training programmes for health workers and physicians in low resource settings, and evaluation of novel interventions to encourage physical activity. Conclusions The experts agreed that the most pressing feasible research questions to address in the next decade for COPD reduction were on prevention, diagnosis and rehabilitation of COPD, especially in low resource settings. The largest gains should be expected in low- and middle-income countries (LMIC) settings, as the large majority of COPD deaths occur in those settings. Research priorities identified by this systematic international process should inform and motivate policymakers, funders, and researchers to support and conduct research to reduce the global burden of COPD

The tectonics of the western Ordos Plateau, Ningxia, China: Slip rates on the Luoshan and East Helanshan Faults

Analysis of the locus, style, and rate of faulting is fundamental to understanding the kinematics of continental deformation. The Ordos Plateau lies to the northeast of Tibet, within the India-Eurasia collision zone. Previous studies have suggested that it behaves rigidly and rotates anticlockwise within a large-scale zone of ENE-WSW left-lateral shearing. For this rotation to be accommodated, the eastern and western margins of the Ordos Plateau should be undergoing right-lateral shearing and yet the dominant faulting style appears to be extensional. We focus specifically on the kinematics of the faults bounding the western margin of the Ordos Plateau and make new slip rate estimates for two of the major faults in the region: the right-lateral strike-slip Luoshan Fault and the normal-slip East Helanshan Fault. We use a combination of infrared stimulated luminescence dating of offset landforms with high-resolution imagery and topography from the Pleiades satellites to determine an average right-lateral slip rate of 4.3 ± 0.4 mm/a (1σ uncertainty) on the Luoshan Fault. Similarly, we use 10Be exposure dating to determine a vertical throw rate on the East Helanshan Fault of <0.6 ± 0.1 mm/a, corresponding to an extension rate of <0.7 ± 0.1 mm/a (1σ uncertainty). Both of these results agree well with slip rates determined from the latest campaign GPS data. We therefore conclude that right-lateral shearing is the dominant motion occurring in the western Ordos region, supporting a kinematic model of large-scale anticlockwise rotation of the whole Ordos Plateau

Satellites reveal Earth's seasonally shifting dust emission sources

Establishing mineral dust impacts on Earth's systems requires numerical models of the dust cycle. Differences between dust optical depth (DOD) measurements and modelling the cycle of dust emission, atmospheric transport, and deposition of dust indicate large model uncertainty due partially to unrealistic model assumptions about dust emission frequency. Calibrating dust cycle models to DOD measurements typically in North Africa, are routinely used to reduce dust model magnitude. This calibration forces modelled dust emissions to match atmospheric DOD but may hide the correct magnitude and frequency of dust emission events at source, compensating biases in other modelled processes of the dust cycle. Therefore, it is essential to improve physically based dust emission modules. Here we use a global collation of satellite observations from previous studies of dust emission point source (DPS) dichotomous frequency data. We show that these DPS data have little-to-no relation with MODIS DOD frequency. We calibrate the albedo-based dust emission model using the frequency distribution of those DPS data. The global dust emission uncertainty constrained by DPS data (±3.8 kg m−2 y−1) provides a benchmark for dust emission model development. Our calibrated model results reveal much less global dust emission (29.1 ± 14.9 Tg y−1) than previous estimates, and show seasonally shifting dust emission predominance within and between hemispheres, as opposed to a persistent North African dust emission primacy widely interpreted from DOD measurements. Earth's largest dust emissions, proceed seasonally from East Asian deserts in boreal spring, to Middle Eastern and North African deserts in boreal summer and then Australian shrublands in boreal autumn-winter. This new analysis of dust emissions, from global sources of varying geochemical properties, have far-reaching implications for current and future dust-climate effects. For more reliable coupled representation of dust-climate projections, our findings suggest the need to re-evaluate dust cycle modelling and benefit from the albedo-based parameterisation