Cassini RADAR images of Titan’s south polar region acquired during southern summer contain lake features which disappear between observations. These features show a tenfold increases in backscatter ...cross-section between images acquired one year apart, which is inconsistent with common scattering models without invoking temporal variability. The morphologic boundaries are transient, further supporting changes in lake level. These observations are consistent with the exposure of diffusely scattering lakebeds that were previously hidden by an attenuating liquid medium. We use a two-layer model to explain backscatter variations and estimate a drop in liquid depth of approximately 1-m-per-year. On larger scales, we observe shoreline recession between ISS and RADAR images of Ontario Lacus, the largest lake in Titan’s south polar region. The recession, occurring between June 2005 and July 2009, is inversely proportional to slopes estimated from altimetric profiles and the exponential decay of near-shore backscatter, consistent with a uniform reduction of 4
±
1.3
m in lake depth.
Of the potential explanations for observed surface changes, we favor evaporation and infiltration. The disappearance of dark features and the recession of Ontario’s shoreline represents volatile transport in an active methane-based hydrologic cycle. Observed loss rates are compared and shown to be consistent with available global circulation models. To date, no unambiguous changes in lake level have been observed between repeat images in the north polar region, although further investigation is warranted. These observations constrain volatile flux rates in Titan’s hydrologic system and demonstrate that the surface plays an active role in its evolution. Constraining these seasonal changes represents the first step toward our understanding of longer climate cycles that may determine liquid distribution on Titan over orbital time periods.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
In this paper we examine a low-energy solar energetic particle (SEP) event observed by IS⊙IS’s Energetic Particle Instrument-Low (EPI-Lo) inside 0.18 au on 2020 September 30. This small SEP ...event has a very interesting time profile and ion composition. Our results show that the maximum energy and peak in intensity are observed mainly along the open radial magnetic field. The event shows velocity dispersion, and strong particle anisotropies are observed throughout the event, showing that more particles are streaming outward from the Sun. We do not see a shock in the in situ plasma or magnetic field data throughout the event. Heavy ions, such as O and Fe, were detected in addition to protons and 4He, but without significant enhancements in 3He or energetic electrons. Our analysis shows that this event is associated with a slow streamer blowout coronal mass ejection (SBO-CME), and the signatures of this small CME event are consistent with those typical of larger CME events. The time–intensity profile of this event shows that the Parker Solar Probe encountered the western flank of the SBO-CME. The anisotropic and dispersive nature of this event in a shockless local plasma gives indications that these particles are most likely accelerated remotely near the Sun by a weak shock or compression wave ahead of the SBO-CME. This event may represent direct observations of the source of the low-energy SEP seed particle population.
Proteins are ubiquitous in molecular biotechnology, biotechnology and as therapeutics, but there are significant challenges in their storage and distribution, with freezing often required. This is ...traditionally achieved by the addition of cryoprotective agents such as glycerol (or trehalose) or covalent modification of mutated proteins with cryoprotectants. Here, ice recrystallization inhibiting polymers, inspired by antifreeze proteins, are used synergistically with poly(ethylene glycol) as an alternative to glycerol. The primary mechanism of action appears to be preventing irreversible aggregation due to ice growth. The polymer formulation is successfully used to cryopreserve a range of important proteins including insulin, Taq DNA polymerase and an IgG antibody. The polymers do not require covalent conjugation, nor modification of the protein and are already used in a wide range of biomedical applications, which will facilitate translation to a range of biologics.
Early observations from the first orbit of Parker Solar Probe (PSP) show recurrent stream interaction regions that form close to the Sun. Energetic particle enhancements were observed on the ...320th–326th day of the year 2018, which corresponds to ~1–7 days after the passage of the stream interface between faster and slower solar wind. Energetic particles stream into the inner heliosphere to the PSP spacecraft near 0.33 au (71 solar radii) where they are measured by the Integrated Science Investigation of the Sun (IS⊙IS). The large 6-day time interval over which energetic particles are observed after the stream passage provides a unique perspective on the development of stream interactions within the heliosphere. The long duration of energetic particle enhancements suggests that particles stream in through the inner heliosphere more directly along magnetic field lines that form a sub-Parker spiral structure due to magnetic footpoint motion at the Sun and shearing of the magnetic field in the rarefaction region behind the stream interface. The strong build-up of energetic particle fluxes in the first 3 days after the passage of the stream interface indicates that suprathermal populations are enhanced near the interaction region through compression or other acceleration processes in addition to being diffusively accelerated. The early increases in energetic particle fluxes (in the first 3 days) in the formation of these events allows for the characterization of the acceleration associated with these suprathermal seed populations. Thus, we show that the time history of energetic particle fluxes observed by IS⊙IS provides a new view of particle acceleration at stream interaction regions throughout the inner heliosphere.
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FMFMET, NUK, UL, UM, UPUK
Summary
A telephone survey was carried out to determine how many United Kingdom intensive care units were using therapeutic hypothermia as part of their management of unconscious patients admitted ...after cardiac arrest. All 247 intensive care units listed in the 2008 Directory of Critical Care Services were contacted to determine how many units were using hypothermia as part of their post‐cardiac arrest management and how it was implemented. We obtained information from 243 (98.4%) of the intensive care units. At the time of the study, 208 (85.6%) were using hypothermia as part of post‐cardiac arrest management. There has been a steady increase annually in the number of units performing therapeutic cooling from 2003 to date, with the majority of units starting in 2007 or 2008. The International Liaison Committee on Resuscitation guidelines, which recommend the use of therapeutic hypothermia for comatose patients following successful resuscitation from cardiac arrest, have taken at least 4–5 years to achieve widespread implementation in the United Kingdom.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This article examines some key similarities and differences between two leading perspectives on public participation: the natural resource management literature and deliberative democratic theory. We ...assert that contemporary deliberative democratic theory, as proposed by Habermas and others, provides important theoretical and applied insights that are often unexamined in the natural resource literature. Specifically, deliberative democratic theory maintains a focus on the value of public deliberation (dialogue and debate), attention to internal as well as external forms of exclusion, and constructive forms of distrust. The article demonstrates that a deliberative democratic perspective on public participation may serve to challenge some established traditions within the natural resource literature and lead to new ways of conducting and evaluating public participation.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons.Experimentally, many new signals have been discovered that could be pointing towards the ...existence of tetraquarks,pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and theoretical issues concerning heavy exotic hadrons is presented.
We present Mars Atmosphere and Volatile EvolutioN observations of large‐amplitude magnetosonic waves propagating through the magnetosheath into the Martian ionosphere near the subsolar point on the ...dayside of the planet. The observed waves grow in amplitude as predicted for a wave propagating into a denser, charged medium, with wave amplitudes reaching 25 nT, equivalent to ∼40% of the background field strength. These waves drive significant density and temperature variations (∼20% to 100% in amplitude) in the suprathermal electrons and light ion species (H+) that correlate with compressional fronts of the magnetosonic waves. Density and temperature variations are also observed for the ionospheric electrons, and heavy ion species (O+ and O
2+); however, these variations are not in phase with the magnetic field variations. Whistler waves are observed at compressional wave fronts and are thought to be produced by unstable, anistropic suprathermal electrons. The magnetosonic waves drive significant ion and electron heating down to just above the exobase region. Ion heating rates are estimated to be between 0.03 and 0.2 eVs−1 per ion, and heavier ions could thus gain escape energy if located in this heating region for ∼10–70 s. The measured ionospheric density profile indicates severe ionospheric erosion above the exobase region, and this is likely caused by substantial ion outflow that is driven by the observed heating. The effectiveness of these magnetosonic waves to energize the plasma close to the exobase could have important implications for the long‐term climate evolution for unmagnetized bodies that are exposed to the solar wind.
Key Points
Magnetosonic waves are observed to propagate from the magnetosheath into the dayside Martian ionosphere
Magnetosonic waves are observed to drive large variations in ionospheric density and temperature
Wave energy is absorbed by the dense O
2+ ionosphere, leading to significant ion heating and substantial ionospheric erosion
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Summary Objective Increasing evidence points to a strong genetic component to osteoarthritis (OA) and that certain changes that occur in osteoarthritic cartilage recapitulate the developmental ...process of endochondral ossification. As zebrafish are a well validated model for genetic studies and developmental biology, our objective was to establish the spatiotemporal expression pattern of a number of OA susceptibility genes in the larval zebrafish providing a platform for functional studies into the role of these genes in OA. Design We identified the zebrafish homologues for Mcf2l, Gdf5, PthrP/Pthlh, Col9a2, and Col10a1 from the Ensembl genome browser. Labelled probes were generated for these genes and in situ hybridisations were performed on wild type zebrafish larvae. In addition, we generated transgenic reporter lines by modification of bacterial artificial chromosomes (BACs) containing full length promoters for col2a1 and col10a1. Results For the first time, we show the spatiotemporal expression pattern of Mcf2l . Furthermore, we show that all six putative OA genes are dynamically expressed during zebrafish larval development, and that all are expressed in the developing skeletal system. Furthermore, we demonstrate that the transgenic reporters we have generated for col2a1 and col10a1 can be used to visualise chondrocyte hypertrophy in vivo. Conclusion In this study we describe the expression pattern of six OA susceptibility genes in zebrafish larvae and the generation of two new transgenic lines marking chondrocytes at different stages of maturation. Moreover, the tools used demonstrate the utility of the zebrafish model for functional studies on genes identified as playing a role in OA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
ABSTRACT The BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in 2004 December and 2007 December at ...substantially different levels of solar modulation. Proton and helium spectra probe the origin and propagation history of cosmic rays in the galaxy, and are essential to calculations of the expected spectra of cosmic-ray antiprotons, positrons, and electrons from interactions of primary cosmic-ray nuclei with the interstellar gas, and to calculations of atmospheric muons and neutrinos. We report absolute spectra at the top of the atmosphere for cosmic-ray protons in the kinetic energy range 0.2-160 GeV and helium nuclei in the range 0.15-80 GeV/nucleon. The corresponding magnetic-rigidity ranges are 0.6-160 GV for protons and 1.1-160 GV for helium. These spectra are compared to measurements from previous BESS flights and from ATIC-2, PAMELA, and AMS-02. We also report the ratio of the proton and helium fluxes from 1.1 to 160 GV and compare this to the ratios from PAMELA and AMS-02.
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