We present stereoscopic images of an Earth‐impacting Coronal Mass Ejection (CME). The CME was imaged by the Heliospheric Imagers onboard the twin STEREO spacecraft during December 2008. The apparent ...acceleration of the CME is used to provide independent estimates of its speed and direction from the two spacecraft. Three distinct signatures within the CME were all found to be closely Earth‐directed. At the time that the CME was predicted to pass the ACE spacecraft, in‐situ observations contained a typical CME signature. At Earth, ground‐based magnetometer observations showed a small but widespread sudden response to the compression of the geomagnetic cavity at CME impact. In this case, STEREO could have given warning of CME impact at least 24 hours in advance. These stereoscopic observations represent a significant milestone for the STEREO mission and have significant potential for improving operational space weather forecasting.
Background
The development of clinical guidelines requires standardised methods informed by robust evidence synthesis.
Objectives
We evaluated the methodological quality of endometriosis guidelines, ...mapped their recommendations, and explored the relationships between recommendations and research evidence.
Search strategy
We searched EMBASE, MEDLINE, and PubMed from inception to February 2016.
Selection criteria
We included guidelines related to the diagnosis and management of endometriosis.
Data collection and analysis
The search strategy identified 879 titles and s. We include two international and five national guidelines. Four independent authors assessed the methodological quality of the included guidelines, using the Appraisal of Guidelines for Research & Evaluation (AGREE‐II) instrument, and systematically extracted the guideline recommendations and supporting research evidence.
Main results
One hundred and fifty‐two different recommendations were made. Ten recommendations (7%) were comparable across guidelines. The European Society of Human Reproduction and Embryology was objectively evaluated as the highest quality guideline (methodological quality score: 88/100). There was substantial variation between the supporting evidence presented by individual guidelines for comparable recommendations. Forty‐two recommendations (28%) were not supported by research evidence. No guideline followed the standardised guideline development methods (AGREE‐II).
Conclusions
There is substantial variation in the recommendations and methodological quality of endometriosis guidelines. Future guidelines should be developed with reference to high‐quality methods in consultation with key stakeholders, including women with endometriosis, ensuring that their scope can truly inform clinical practice and eliminate unwarranted and unjustified variations in clinical practice.
Tweetable
#Endometriosis guidelines vary in recommendations and quality. @EndometriosisUK
Tweetable
#Endometriosis guidelines vary in recommendations and quality. @EndometriosisUK.
This paper includes Author Insights, a video available at https://vimeo.com/rcog/authorinsights14838
The two main ultraviolet‐signatures resulting from the Io‐magnetosphere interaction are the local auroras on Io's atmosphere, and the Io footprints on Jupiter. We study here how Io's daily eclipses ...affect the footprint. Previous observations showed that its atmosphere collapses in eclipse. While remote observers can observe Io's local auroras briefly when Io disappears behind Jupiter, Juno is able to follow the Io footprint in the unlit hemisphere. Theoretical models of the variability of the energy flux fed into the Alfvén wings, ultimately powering the footprints, are not sufficiently constrained by observations. For the first time, we use observations of Io's footprint from the Ultraviolet Spectrograph (UVS) on Juno recorded as Io went into eclipse. We benchmark the trend of the footprint brightness using observations by UVS taken over Io's complete orbit and find that the footprint emitted power variation with Jupiter's rotation shows fairly consistent trends with previous observations. Two exploitable data sets provided measurements when Io was simultaneously in eclipse. No statistically significant changes were recorded as Io left and moved into eclipse, respectively, suggesting either that (i) Io's atmospheric densities within and outside eclipse are large enough to produce a saturated plasma interaction, that is, in the saturated state, changes in Io's atmospheric properties to first order do not control the total Alfvénic energy flux, (ii) the atmospheric collapse during the Juno observations was less than previously observed, or (iii) additional processes of the Alfvén wings in addition to the Poynting flux generated at Io control the footprint luminosity.
Key Points
Juno‐UVS observed for the first time the Io footprints while Io went into eclipse
The effect of Io's atmospheric collapse on the footprint emitted power is investigated
No significant variation of the footprint emitted power is observed during eclipse
The elementary CuO
2
plane sustaining cuprate high-temperature superconductivity occurs typically at the base of a periodic array of edge-sharing CuO
5
pyramids. Virtual transitions of electrons ...between adjacent planar Cu and O atoms, occurring at a rate t/ℏ and across the charge-transfer energy gap
E
, generate “superexchange” spin–spin interactions of energy
J
≈
4
t
4
/
E
3
in an antiferromagnetic correlated-insulator state. However, hole doping this CuO
2
plane converts this into a very-high-temperature superconducting state whose electron pairing is exceptional. A leading proposal for the mechanism of this intense electron pairing is that, while hole doping destroys magnetic order, it preserves pair-forming superexchange interactions governed by the charge-transfer energy scale
E
. To explore this hypothesis directly at atomic scale, we combine single-electron and electron-pair (Josephson) scanning tunneling microscopy to visualize the interplay of
E
and the electron-pair density
n
P
in Bi
2
Sr
2
CaCu
2
O
8+x
. The responses of both
E
and
n
P
to alterations in the distance
δ
between planar Cu and apical O atoms are then determined. These data reveal the empirical crux of strongly correlated superconductivity in CuO
2
, the response of the electron-pair condensate to varying the charge-transfer energy. Concurrence of predictions from strong-correlation theory for hole-doped charge-transfer insulators with these observations indicates that charge-transfer superexchange is the electron-pairing mechanism of superconductive Bi
2
Sr
2
CaCu
2
O
8+x
.
We study the coexisting smectic modulations and intra—unit-cell nematicity in the pseudogap states of underdoped Bi 2 Sr 2 CaCu 2 O 8+δ . By visualizing their spatial components separately, we ...identified 2π topological defects throughout the phase-fluctuating smectic states. Imaging the locations of large numbers of these topological defects simultaneously with the fluctuations in the intra—unit-cell nematicity revealed strong empirical evidence for a coupling between them. From these observations, we propose a Ginzburg-Landau functional describing this coupling and demonstrate how it can explain the coexistence of the smectic and intra—unit-cell broken symmetries and also correctly predict their interplay at the atomic scale. This theoretical perspective can lead to unraveling the complexities of the phase diagram of cuprate high-critical-temperature superconductors.
Threatened marine megafauna have larger-than-expected contributions to functional diversity; a new index identifies key species.
Marine megafauna, the largest animals in the oceans, serve key roles ...in ecosystem functioning. Yet, one-third of these animals are at risk of extinction. To better understand the potential consequences of megafaunal loss, here we quantify their current functional diversity, predict future changes under different extinction scenarios, and introduce a new metric functionally unique, specialized and endangered (FUSE) that identifies threatened species of particular importance for functional diversity. Simulated extinction scenarios forecast marked declines in functional richness if current trajectories are maintained during the next century (11% globally; up to 24% regionally), with more marked reductions (48% globally; up to 70% at the poles) beyond random expectations if all threatened species eventually go extinct. Among the megafaunal groups, sharks will incur a disproportionate loss of functional richness. We identify top FUSE species and suggest a renewed focus on these species to preserve the ecosystem functions provided by marine megafauna.
We discuss the influence on spin-fluctuation pairing theory of orbital selective strong correlation effects in Fe-based superconductors, particularly Fe chalcogenide systems. We propose that a key ...ingredient for an improved itinerant pairing theory is orbital selectivity, i.e., incorporating the reduced coherence of quasiparticles occupying specific orbital states. This modifies the usual spin-fluctuation theory via suppression of pair scattering processes involving those less coherent states and results in orbital selective Cooper pairing of electrons in the remaining states. We show that this paradigm yields remarkably good agreement with the experimentally observed anisotropic gap structures in both bulk and monolayer FeSe, as well as LiFeAs, indicating that orbital selective Cooper pairing plays a key role in the more strongly correlated iron-based superconductors.
Abstract
We introduce the Automatic Learning for the Rapid Classification of Events (ALeRCE) broker, an astronomical alert broker designed to provide a rapid and self-consistent classification of ...large etendue telescope alert streams, such as that provided by the Zwicky Transient Facility (ZTF) and, in the future, the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). ALeRCE is a Chilean-led broker run by an interdisciplinary team of astronomers and engineers working to become intermediaries between survey and follow-up facilities. ALeRCE uses a pipeline that includes the real-time ingestion, aggregation, cross-matching, machine-learning (ML) classification, and visualization of the ZTF alert stream. We use two classifiers: a stamp-based classifier, designed for rapid classification, and a light curve–based classifier, which uses the multiband flux evolution to achieve a more refined classification. We describe in detail our pipeline, data products, tools, and services, which are made public for the community (see
https://alerce.science
). Since we began operating our real-time ML classification of the ZTF alert stream in early 2019, we have grown a large community of active users around the globe. We describe our results to date, including the real-time processing of 1.5 × 10
8
alerts, the stamp classification of 3.4 × 10
7
objects, the light-curve classification of 1.1 × 10
6
objects, the report of 6162 supernova candidates, and different experiments using LSST-like alert streams. Finally, we discuss the challenges ahead in going from a single stream of alerts such as ZTF to a multistream ecosystem dominated by LSST.
The Parker Solar Probe was launched on 2018 August 12 and completed its second orbit on 2019 June 19 with perihelion of 35.7 solar radii. During this time, the Energetic Particle Instrument-Hi ...(EPI-Hi, one of the two energetic particle instruments comprising the Integrated Science Investigation of the Sun, IS IS) measured seven proton intensity increases associated with stream interaction regions (SIRs), two of which appear to be occurring in the same region corotating with the Sun. The events are relatively weak, with observed proton spectra extending to only a few MeV and lasting for a few days. The proton spectra are best characterized by power laws with indices ranging from −4.3 to −6.5, generally softer than events associated with SIRs observed at 1 au and beyond. Helium spectra were also obtained with similar indices, allowing He/H abundance ratios to be calculated for each event. We find values of 0.016-0.031, which are consistent with ratios obtained previously for corotating interaction region events with fast solar wind ≤600 km s−1. Using the observed solar wind data combined with solar wind simulations, we study the solar wind structures associated with these events and identify additional spacecraft near 1 au appropriately positioned to observe the same structures after some corotation. Examination of the energetic particle observations from these spacecraft yields two events that may correspond to the energetic particle increases seen by EPI-Hi earlier.
Magnetic monopole noise Dusad, Ritika; Kirschner, Franziska K K; Hoke, Jesse C ...
Nature (London),
07/2019, Letnik:
571, Številka:
7764
Journal Article
Recenzirano
Odprti dostop
Magnetic monopoles
are hypothetical elementary particles with quantized magnetic charge. In principle, a magnetic monopole can be detected by the quantized jump in magnetic flux that it generates ...upon passage through a superconducting quantum interference device (SQUID)
. Following the theoretical prediction that emergent magnetic monopoles should exist in several lanthanide pyrochlore magnetic insulators
, including Dy
Ti
O
, the SQUID technique has been proposed for their direct detection
. However, this approach has been hindered by the high number density and the generation-recombination fluctuations expected of such thermally generated monopoles. Recently, theoretical advances have enabled the prediction of the spectral density of magnetic-flux noise from monopole generation-recombination fluctuations in these materials
. Here we report the development of a SQUID-based flux noise spectrometer and measurements of the frequency and temperature dependence of magnetic-flux noise generated by Dy
Ti
O
crystals. We detect almost all of the features of magnetic-flux noise predicted for magnetic monopole plasmas
, including the existence of intense magnetization noise and its characteristic frequency and temperature dependence. Moreover, comparisons of simulated and measured correlation functions of the magnetic-flux noise indicate that the motions of magnetic charges are strongly correlated. Intriguingly, because the generation-recombination time constant for Dy
Ti
O
is in the millisecond range, magnetic monopole flux noise amplified by SQUID is audible to humans.
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