Most studies have some missing data. Jonathan Sterne and colleagues describe the appropriate use and reporting of the multiple imputation approach to dealing with them
This study quantifies mean annual and monthly fluxes of Earth’s water cycle over continents and ocean basins during the first decade of the millennium. To the extent possible, the flux estimates are ...based on satellite measurements first and data-integrating models second. A careful accounting of uncertainty in the estimates is included. It is applied within a routine that enforces multiple water and energy budget constraints simultaneously in a variational framework in order to produce objectively determined optimized flux estimates. In the majority of cases, the observed annual surface and atmospheric water budgets over the continents and oceans close with much less than 10% residual. Observed residuals and optimized uncertainty estimates are considerably larger for monthly surface and atmospheric water budget closure, often nearing or exceeding 20% in North America, Eurasia, Australia and neighboring islands, and the Arctic and South Atlantic Oceans. The residuals in South America and Africa tend to be smaller, possibly because cold land processes are negligible. Fluxes were poorly observed over the Arctic Ocean, certain seas, Antarctica, and the Australasian and Indonesian islands, leading to reliance on atmospheric analysis estimates. Many of the satellite systems that contributed data have been or will soon be lost or replaced. Models that integrate ground-based and remote observations will be critical for ameliorating gaps and discontinuities in the data records caused by these transitions. Continued development of such models is essential for maximizing the value of the observations. Next-generation observing systems are the best hope for significantly improving global water budget accounting.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The performance of a new historical reanalysis, the NOAA–CIRES–DOE Twentieth Century Reanalysis version 3 (20CRv3), is evaluated via comparisons with other reanalyses and independent observations. ...This dataset provides global, 3-hourly estimates of the atmosphere from 1806 to 2015 by assimilating only surface pressure observations and prescribing sea surface temperature, sea ice concentration, and radiative forcings. Comparisons with independent observations, other reanalyses, and satellite products suggest that 20CRv3 can reliably produce atmospheric estimates on scales ranging from weather events to long-term climatic trends. Not only does 20CRv3 recreate a ‘‘best estimate’’ of the weather, including extreme events, it also provides an estimate of its confidence through the use of an ensemble. Surface pressure statistics suggest that these confidence estimates are reliable. Comparisons with independent upper-air observations in the Northern Hemisphere demonstrate that 20CRv3 has skill throughout the twentieth century. Upper-air fields from 20CRv3 in the late twentieth century and early twenty-first century correlate well with full-input reanalyses, and the correlation is predicted by the confidence fields from 20CRv3. The skill of analyzed 500-hPa geopotential heights from 20CRv3 for 1979–2015 is comparable to that of modern operational 3–4-day forecasts. Finally, 20CRv3 performs well on climate time scales. Long time series and multidecadal averages of mass, circulation, and precipitation fields agree well with modern reanalyses and station- and satellite-based products. 20CRv3 is also able to capture trends in tropospheric-layer temperatures that correlate well with independent products in the twentieth century, placing recent trends in a longer historical context.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
New objectively balanced observation-based reconstructions of global and continental energy budgets and their seasonal variability are presented that span the golden decade of Earth-observing ...satellites at the start of the twenty-first century. In the absence of balance constraints, various combinations of modern flux datasets reveal that current estimates of net radiation into Earth’s surface exceed corresponding turbulent heat fluxes by 13–24 W m−2. The largest imbalances occur over oceanic regions where the component algorithms operate independent of closure constraints. Recent uncertainty assessments suggest that these imbalances fall within anticipated error bounds for each dataset, but the systematic nature of required adjustments across different regions confirm the existence of biases in the component fluxes. To reintroduce energy and water cycle closure information lost in the development of independent flux datasets, a variational method is introduced that explicitly accounts for the relative accuracies in all component fluxes. Applying the technique to a 10-yr record of satellite observations yields new energy budget estimates that simultaneously satisfy all energy and water cycle balance constraints. Globally, 180 W m−2of atmospheric longwave cooling is balanced by 74 W m−2of shortwave absorption and 106 W m−2of latent and sensible heat release. At the surface, 106 W m−2of downwelling radiation is balanced by turbulent heat transfer to within a residual heat flux into the oceans of 0.45 W m−2, consistent with recent observations of changes in ocean heat content. Annual mean energy budgets and their seasonal cycles for each of seven continents and nine ocean basins are also presented.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
In twin pregnancies, the rates of adverse perinatal outcome and subsequent long‐term morbidity are substantial, and mainly result from preterm birth (PTB).
Objectives
To assess the ...effectiveness of progestogen treatment in the prevention of neonatal morbidity or PTB in twin pregnancies using individual participant data meta‐analysis (IPDMA).
Search strategy
We searched international scientific databases, trial registration websites, and references of identified articles.
Selection criteria
Randomised clinical trials (RCTs) of 17–hydroxyprogesterone caproate (17Pc) or vaginally administered natural progesterone, compared with placebo or no treatment.
Data collection and analysis
Investigators of identified RCTs were asked to share their IPD. The primary outcome was a composite of perinatal mortality and severe neonatal morbidity. Prespecified subgroup analyses were performed for chorionicity, cervical length, and prior spontaneous PTB.
Main results
Thirteen trials included 3768 women and their 7536 babies. Neither 17Pc nor vaginal progesterone reduced the incidence of adverse perinatal outcome (17Pc relative risk, RR 1.1; 95% confidence interval, 95% CI 0.97–1.4, vaginal progesterone RR 0.97; 95% CI 0.77–1.2). In a subgroup of women with a cervical length of ≤25 mm, vaginal progesterone reduced adverse perinatal outcome when cervical length was measured at randomisation (15/56 versus 22/60; RR 0.57; 95% CI 0.47–0.70) or before 24 weeks of gestation (14/52 versus 21/56; RR 0.56; 95% CI 0.42–0.75).
Author's conclusions
In unselected women with an uncomplicated twin gestation, treatment with progestogens (intramuscular 17Pc or vaginal natural progesterone) does not improve perinatal outcome. Vaginal progesterone may be effective in the reduction of adverse perinatal outcome in women with a cervical length of ≤25 mm; however, further research is warranted to confirm this finding.
Objective To examine whether the association of inadequate or unclear allocation concealment and lack of blinding with biased estimates of intervention effects varies with the nature of the ...intervention or outcome.Design Combined analysis of data from three meta-epidemiological studies based on collections of meta-analyses.Data sources 146 meta-analyses including 1346 trials examining a wide range of interventions and outcomes.Main outcome measures Ratios of odds ratios quantifying the degree of bias associated with inadequate or unclear allocation concealment, and lack of blinding, for trials with different types of intervention and outcome. A ratio of odds ratios <1 implies that inadequately concealed or non-blinded trials exaggerate intervention effect estimates.Results In trials with subjective outcomes effect estimates were exaggerated when there was inadequate or unclear allocation concealment (ratio of odds ratios 0.69 (95% CI 0.59 to 0.82)) or lack of blinding (0.75 (0.61 to 0.93)). In contrast, there was little evidence of bias in trials with objective outcomes: ratios of odds ratios 0.91 (0.80 to 1.03) for inadequate or unclear allocation concealment and 1.01 (0.92 to 1.10) for lack of blinding. There was little evidence for a difference between trials of drug and non-drug interventions. Except for trials with all cause mortality as the outcome, the magnitude of bias varied between meta-analyses.Conclusions The average bias associated with defects in the conduct of randomised trials varies with the type of outcome. Systematic reviewers should routinely assess the risk of bias in the results of trials, and should report meta-analyses restricted to trials at low risk of bias either as the primary analysis or in conjunction with less restrictive analyses.
Forest edges influence more than half of the world's forests and contribute to worldwide declines in biodiversity and ecosystem functions. However, predicting these declines is challenging in ...heterogeneous fragmented landscapes. Here we assembled a global dataset on species responses to fragmentation and developed a statistical approach for quantifying edge impacts in heterogeneous landscapes to quantify edge-determined changes in abundance of 1,673 vertebrate species. We show that the abundances of 85% of species are affected, either positively or negatively, by forest edges. Species that live in the centre of the forest (forest core), that were more likely to be listed as threatened by the International Union for Conservation of Nature (IUCN), reached peak abundances only at sites farther than 200-400 m from sharp high-contrast forest edges. Smaller-bodied amphibians, larger reptiles and medium-sized non-volant mammals experienced a larger reduction in suitable habitat than other forest-core species. Our results highlight the pervasive ability of forest edges to restructure ecological communities on a global scale.
Abstract Radio-frequency particle accelerators are engines of discovery, powering high-energy physics and photon science, but are also large and expensive due to their limited accelerating fields. ...Plasma-wakefield accelerators (PWFAs) provide orders-of-magnitude stronger fields in the charge-density wave behind a particle bunch travelling in a plasma, promising particle accelerators of greatly reduced size and cost. However, PWFAs can easily degrade the beam quality of the bunches they accelerate. Emittance, which determines how tightly beams can be focused, is a critical beam quality in for instance colliders and free-electron lasers, but is particularly prone to degradation. We demonstrate, for the first time, emittance preservation in a high-gradient and high-efficiency PWFA while simultaneously preserving charge and energy spread. This establishes that PWFAs can accelerate without degradation—an essential step toward energy boosters in photon science and multistage facilities for compact high-energy particle colliders.
The supercapsular percutaneously assisted total hip (SuperPATH) approach was designed to be a less-invasive surgical approach to THA. This approach may have advantages, including less pain, more ...rapid mobilization, and shorter hospital length of stay. However, few published studies have compared the SuperPATH technique to existing standard approaches in a randomized, controlled manner.
In this study, we asked: (1) Do patients with SuperPATH demonstrate improved early function, using the timed up and go (TUG) and timed stair climbing (TSC) tests as instruments for assessment during the first 100 days postoperatively? (2) Are patient-reported outcomes, in the form of Oxford Hip Scores, better for the SuperPATH group during the first 3 months postoperatively? (3) Are opioid consumption and pain score in the first month postoperatively different between patients undergoing SuperPATH and patients undergoing a standard posterior approach? (4) Are patients with SuperPATH able to discontinue using mobility aids and return to work more quickly?
Between February 2017 and May 2019, 46% (46 of 101) of patients were recruited among 101 patients who met our inclusion criteria. Those 46 patients were randomized into two groups on the day of surgery; 54% (25 of 46) were assigned to the study group (SuperPATH approach) and 46% (21 of 46) were assigned to the control group (posterior approach). The SuperPATH technique uses the plane between the gluteus medius and the external rotators while preserving the piriformis and the superior aspect of the capsule. A percutaneous accessory portal is required for acetabular reaming and cup insertion. The posterior approach involves releasing short rotators and partially releasing the quadratus femoris while retaining the gluteus maximus's insertion site. The two groups did not differ in BMI, gender, American Society of Anesthesiologists class, surgical side, or diagnosis. The length of stay, component position, and blood loss were similar between the groups, but the operative time was longer in the SuperPATH group than in the group with the posterior approach. One patient from the control group was lost to follow-up and was excluded. Three patients in the study group had complications. The TUG and TSC tests are timed tasks for the patient. In the TUG test, patients stand from sitting, walk 3 meters and turn, walk back, and sit down. The TSC test measures the time taken to ascend and descend 10 steps. Patients were followed for 24 months for any complications.
The TUG time at 100 days was 8.9 ± 2.6 seconds in the SuperPATH group and 8.7 ± 2.2 seconds in the posterior group (mean difference -0.2 seconds 95% CI -1.8 to 1.4; p = 0.98); results were similar at other timepoints. The TSC time at 100 days was 11.6 ± 4.7 seconds in the SuperPATH group and 10.8 ± 3.6 seconds in the posterior group (mean difference -0.7 seconds 95% CI -3.5 to 2.1; p = 0.88), and there were no differences between the two groups at all timepoints. The Oxford Hip Score showed no difference at any point postoperatively. At 6 weeks, it was 36 ± 5.9 points in the SuperPATH group and 38 ± 8.6 in the posterior group (mean difference 1.7 points 95% CI -2.7 to 6.1; p = 0.51). At 3 months, it was 42± 6.7 points in the SuperPATH group and 41 ± 10.2 points in the posterior group (mean difference 0.7 points 95% CI -6.2 to 4.9; p = 0.34). Patients' pain scores did not show any differences at all tested timepoints (mean difference 1 95% CI -0.2 to 2.2; p = 0.102). Total opioid consumption in the posterior group was higher in the first 2 weeks than that in the SuperPATH group (mean difference 6 95% CI 2.3 to 9.9; p = 0.001), but there was no difference in either group by week 4 (mean difference 0.4 95% CI -0.5 to 1.4; p = 0.36). There was no difference in return to work between the SuperPATH group and the posterior approach group (mean difference 6 days 95% CI -29 to 41; p = 0.74). Discontinuation of mobility aids was similar between the two groups (mean difference 0.9 days 95% CI -25 to 27; p = 0.94).
The SuperPATH approach had no clinical advantages over the posterior approach, resulted in more complications, and only showed a short-term reduction in pain. The results of our small randomized controlled trial can be used to calculate future sample sizes, but our data suggest that any differences favoring the SuperPATH approach are likely to be small and transient. This approach should not be used routinely in clinical practice until an adequately powered trial shows clinically important differences in patient-relevant endpoints. The improved postoperative recovery is likely multifactorial and not dependent on the invasiveness of the approach.
Level II, therapeutic study.
ABSTRACT
During a 2018 outburst, the black hole X-ray binary MAXI J1820 + 070 was comprehensively monitored at multiple wavelengths as it underwent a hard to soft state transition. During this ...transition, a rapid evolution in X-ray timing properties and a short-lived radio flare were observed, both of which were linked to the launching of bi-polar, long-lived relativistic ejecta. We provide a detailed analysis of two Very Long Baseline Array observations, using both time binning and a new dynamic phase centre tracking technique to mitigate the effects of smearing when observing fast-moving ejecta at high angular resolution. We identify a second, earlier ejection, with a lower proper motion of 18.0 ± 1.1 mas d−1. This new jet knot was ejected 4 ± 1 h before the beginning of the rise of the radio flare, and 2 ± 1 h before a switch from type-C to type-B X-ray quasi-periodic oscillations (QPOs). We show that this jet was ejected over a period of ∼6 h and thus its ejection was contemporaneous with the QPO transition. Our new technique locates the original, faster ejection in an observation in which it was previously undetected. With this detection, we revised the fits to the proper motions of the ejecta and calculated a jet inclination angle of (64 ± 5)°, and jet velocities of $0.97_{-0.09}^{+0.03}c$ for the fast-moving ejecta (Γ > 2.1) and (0.30 ± 0.05)c for the newly identified slow-moving ejection (Γ = 1.05 ± 0.02). We show that the approaching slow-moving component is predominantly responsible for the radio flare, and is likely linked to the switch from type-C to type-B QPOs, while no definitive signature of ejection was identified for the fast-moving ejecta.
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