Oblique Propagation and Refraction of Gravity Waves Over the Andes Observed by GLORIA and ALIMA During the SouthTRAC Campaign

Gravity waves (GW) carry energy and momentum from the troposphere to the middle atmosphere and have a strong influence on the circulation there. Global atmospheric models cannot fully resolve GWs, and therefore rely on highly simplified GW parametrizations that, among other limitations, account for vertical wave propagation only and neglect refraction. This is a major source of uncertainty in models, and leads to well-known problems, such as the late break-up of polar vortex due to the “missing” GW drag around 60°S. To investigate these phenomena, GW observations over Southern Andes were performed during SouthTRAC aircraft campaign. This paper presents measurements from a SouthTRAC flight on 21 September 2019, including 3-D tomographic temperature data of the infrared limb imager GLORIA (8–15 km altitude) and temperature profiles of the ALIMA lidar (20–80 km altitude). GLORIA observations revealed multiple overlapping waves of different wavelengths. 3-D wave vectors were determined from the GLORIA data and used to initialize a GW ray-tracer. The ray-traced GW parameters were compared with ALIMA observations, showing good agreement between the instruments and direct evidence of oblique (partly meridional) GW propagation. ALIMA data analysis confirmed that most waves at 25–40 km altitudes were indeed orographic GWs, including waves seemingly upstream of the Andes. We directly observed horizontal GW refraction, which has not been achieved before SouthTRAC. Refraction and oblique propagation caused significant meridional transport of horizontal momentum as well as horizontal momentum exchange between waves and the background flow all along the wave paths, not just in wave excitation and breaking regions

3-D tomographic observations of Rossby wave breaking over the North Atlantic during the WISE aircraft campaign in 2017

This paper presents measurements of ozone, water vapour and nitric acid (HNO3) in the upper troposphere/lower stratosphere (UTLS) over North Atlantic and Europe. The measurements were acquired with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the Wave Driven Isentropic Exchange (WISE) campaign in October 2017. GLORIA is an airborne limb imager capable of acquiring both 2-D data sets (curtains along the flight path) and, when the carrier aircraft is flying around the observed air mass, spatially highly resolved 3-D tomographic data. Here, we present a case study of a Rossby wave (RW) breaking event observed during two subsequent flights 2 d apart. RW breaking is known to steepen tracer gradients and facilitate stratosphere–troposphere exchange (STE). Our measurements reveal complex spatial structures in stratospheric tracers (ozone and nitric acid) with multiple vertically stacked filaments. Backward-trajectory analysis is used to demonstrate that these features are related to several previous Rossby wave breaking events and that the small-scale structure of the UTLS in the Rossby wave breaking region, which is otherwise very hard to observe, can be understood as stirring and mixing of air masses of tropospheric and stratospheric origin. It is also shown that a strong nitric acid enhancement observed just above the tropopause is likely a result of NOx production by lightning activity. The measurements showed signatures of enhanced mixing between stratospheric and tropospheric air near the polar jet with some transport of water vapour into the stratosphere. Some of the air masses seen in 3-D data were encountered again 2 d later, stretched to very thin filament (horizontal thickness down to 30 km at some altitudes) rich in stratospheric tracers. This repeated measurement allowed us to directly observe and analyse the progress of mixing processes in a thin filament over 2 d. Our results provide direct insight into small-scale dynamics of the UTLS in the Rossby wave breaking region, which is of great importance to understanding STE and poleward transport in the UTLS

Blending using ODE swept surfaces with shape control and C1 continuity

Surface blending with tangential continuity is most widely applied in computer aided design, manufacturing systems, and geometric modeling. In this paper, we propose a new blending method to effectively control the shape of blending surfaces, which can also satisfy the blending constraints of tangent continuity exactly. This new blending method is based on the concept of swept surfaces controlled by a vector-valued fourth order ordinary differential equation (ODE). It creates blending surfaces by sweeping a generator along two trimlines and making the generator exactly satisfy the tangential constraints at the trimlines. The shape of blending surfaces is controlled by manipulating the generator with the solution to a vector-valued fourth order ODE. This new blending methods have the following advantages: 1). exact satisfaction of 1C continuous blending boundary constraints, 2). effective shape control of blending surfaces, 3). high computing efficiency due to explicit mathematical representation of blending surfaces, and 4). ability to blend multiple (more than two) primary surfaces

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Oblique Propagation and Refraction of Gravity Waves Over the Andes Observed by GLORIA and ALIMA During the SouthTRAC Campaign

AbstractGravity waves (GW) carry energy and momentum from the troposphere to the middle atmosphere and have a strong influence on the circulation there. Global atmospheric models cannot fully resolve GWs, and therefore rely on highly simplified GW parametrizations that, among other limitations, account for vertical wave propagation only and neglect refraction. This is a major source of uncertainty in models, and leads to well‐known problems, such as the late break‐up of polar vortex due to the “missing” GW drag around 60°S. To investigate these phenomena, GW observations over Southern Andes were performed during SouthTRAC aircraft campaign. This paper presents measurements from a SouthTRAC flight on 21 September 2019, including 3‐D tomographic temperature data of the infrared limb imager GLORIA (8–15 km altitude) and temperature profiles of the ALIMA lidar (20–80 km altitude). GLORIA observations revealed multiple overlapping waves of different wavelengths. 3‐D wave vectors were determined from the GLORIA data and used to initialize a GW ray‐tracer. The ray‐traced GW parameters were compared with ALIMA observations, showing good agreement between the instruments and direct evidence of oblique (partly meridional) GW propagation. ALIMA data analysis confirmed that most waves at 25–40 km altitudes were indeed orographic GWs, including waves seemingly upstream of the Andes. We directly observed horizontal GW refraction, which has not been achieved before SouthTRAC. Refraction and oblique propagation caused significant meridional transport of horizontal momentum as well as horizontal momentum exchange between waves and the background flow all along the wave paths, not just in wave excitation and breaking regions.Plain Language Summary: Gravity waves (GW) are temperature and wind disturbances in the atmosphere that carry energy and momentum from troposphere to the middle atmosphere and have a strong influence on the circulation there. Global atmospheric models currently cannot adequately represent GW propagation: the facts that GWs can change wavefront orientation (refraction) and travel horizontally (and not just vertically) are typically neglected. This leads to important known model inaccuracies, for example, too low temperatures in southern polar regions. SouthTRAC aircraft measurement campaign observed GWs exited by wind flow over the Southern Andes in September–November 2019. Temperature measurements were conducted with the IR spectrometer GLORIA (provided 3‐D data) and the ALIMA lidar instrument. GLORIA data revealed many overlapping waves of different wavelengths, their propagation further up was investigated using ray‐tracing. Most waves seen by GLORIA were ray‐traced to ALIMA observations where their parameters were confirmed, thus validating our ray‐tracing technique and the two instruments against each other. We directly observed wave propagation in both vertical and horizontal directions and change in horizontal wave orientation (the latter was not seen before SouthTRAC). Due to these phenomena, many GWs carried momentum that had different directions and was deposited in a different location than most models typically predict.Key Points: High‐resolution multi‐instrument measurements of orographic gravity waves (GWs) over the Andes were carried out. Oblique GW propagation and strong horizontal refraction were observed and analyzed using ray‐tracing. Significant redistribution of horizontal momentum due to horizontal refraction was observed all along the path of wave propagation.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659German Ministry for Education and ResearchBundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347https://www.ecmwf.int/en/forecasts/datasetshttps://doi.org/10.5281/zenodo.715572

Characterization of purified human Bact spliceosomal complexes reveals compositional and morphological changes during spliceosome activation and first step catalysis

To better understand the compositional and structural dynamics of the human spliceosome during its activation, we set out to isolate spliceosomal complexes formed after precatalytic B but prior to catalytically active C complexes. By shortening the polypyrimidine tract of the PM5 pre-mRNA, which lacks a 3′ splice site and 3′ exon, we stalled spliceosome assembly at the activation stage. We subsequently affinity purified human Bact complexes under the same conditions previously used to isolate B and C complexes, and analyzed their protein composition by mass spectrometry. A comparison of the protein composition of these complexes allowed a fine dissection of compositional changes during the B to Bact and Bact to C transitions, and comparisons with the Saccharomyces cerevisiae Bact complex revealed that the compositional dynamics of the spliceosome during activation are largely conserved between lower and higher eukaryotes. Human SF3b155 and CDC5L were shown to be phosphorylated specifically during the B to Bact and Bact to C transition, respectively, suggesting these modifications function at these stages of splicing. The two-dimensional structure of the human Bact complex was determined by electron microscopy, and a comparison with the B complex revealed that the morphology of the human spliceosome changes significantly during its activation. The overall architecture of the human and S. cerevisiae Bact complex is similar, suggesting that many of the higher order interactions among spliceosomal components, as well as their dynamics, are also largely conserved

Observations of Gravity Wave Refraction and Its Causes and Consequences

Horizontal gravity wave (GW) refraction was observed around the Andes and Drake Passage during the SouthTRAC campaign. GWs interact with the background wind through refraction and dissipation. This interaction helps to drive midatmospheric circulations and slows down the polar vortex by taking GW momentum flux (GWMF) from one location to another. The SouthTRAC campaign was composed to gain improved understanding of the propagation and dissipation of GWs. This study uses observational data from this campaign collected by the German High Altitude Long Range research aircraft on 12 September 2019. During the campaign a minor sudden stratospheric warming in the southern hemisphere occurred, which heavily influenced GW propagation and refraction and thus also the location and amount of GWMF deposition. Observations include measurements from below the aircraft by Gimballed Limb Observer for Radiance Imaging of the Atmosphere and above the aircraft by Airborne Lidar for the Middle Atmosphere. Refraction is identified in two different GW packets as low as ≈4 km and as high as 58 km. One GW packet of orographic origin and one of nonorographic origin is used to investigate refraction. Observations are supplemented by the Gravity‐wave Regional Or Global Ray Tracer, a simplified mountain wave model, ERA5 data and high‐resolution (3 km) WRF data. Contrary to some previous studies we find that refraction makes a noteworthy contribution in the amount and the location of GWMF deposition. This case study highlights the importance of refraction and provides compelling arguments that models should account for this.Plain Language Summary: Gravity waves (GWs) are very important for models to reproduce a midatmospheric circulations. But the fact is that models oversimplify the GW physics which results in GWs being underrepresented in models. GW refraction is one of the processes not captured by the physics in model parameterization schemes. This article uses high‐resolution observations from the SouthTRAC campaign to show how GWs refract and highlight the importance there‐of. This case study shows a 25% increase in the GWMF during propagation. The increase in momentum flux is linked to refraction which results in a shortening in the GW horizontal wavelength. This article shows that refraction is important for the amount as well as the location of GWMF deposition. This case study highlights the importance of refraction and provides compelling arguments that models should account for this.Key Points: A case study reveals that refraction results in a 25% increase in gravity wave momentum flux (GWMF). Including refraction dynamics affects the location of GWMF deposition. Refraction is prominent in strong wind gradients (i.e., displaced vortex conditions).ANPCYT PICTDFGBundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347Instituto de Física de Buenos AiresSNCAD MinCyT initiativeHALO‐SPPROMIC WASCLIMhttps://doi.org/10.5281/zenodo.6997443https://cds.climate.copernicus.eu/cdsapp%23%21/hom

Thigh-length compression stockings and DVT after stroke

Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease