Going beyond two degrees? The risks and opportunities of alternative options

Since the mid-1990s, the aim of keeping climate change within 2 °C has become firmly entrenched in policy discourses. In the past few years, the likelihood of achieving it has been increasingly called into question. The debate around what to do with a target that seems less and less achievable is, however, only just beginning. As the UN commences a two-year review of the 2 °C target, this article moves beyond the somewhat binary debates about whether or not it should or will be met, in order to analyse more fully some of the alternative options that have been identified but not fully explored in the existing literature. For the first time, uncertainties, risks, and opportunities associated with four such options are identified and synthesized from the literature. The analysis finds that the significant risks and uncertainties associated with some options may encourage decision makers to recommit to the 2 °C target as the least unattractive course of action

Static self-gravitating elastic bodies in Einstein gravity

We prove that given a stress-free elastic body there exists, for sufficiently small values of the gravitational constant, a unique static solution of the Einstein equations coupled to the equations of relativistic elasticity. The solution constructed is a small deformation of the relaxed configuration. This result yields the first proof of existence of static solutions of the Einstein equations without symmetries.Comment: 29 pages. Updated to conform with published version, typos fixe

Composition of Near-Earth Asteroid 2008 EV5: Potential target for Robotic and Human Exploration

We observed potentially hazardous asteroid (PHA) 2008 EV5 in the visible (0.30-0.92 microns) and near-IR (0.75-2.5 microns) wavelengths to determine its surface composition. This asteroid is especially interesting because it is a potential target for two sample return mission proposals (Marco Polo-R and Hayabusa-2) and human exploration due to its low delta-v for rendezvous. The spectrum of 2008 EV5 is essentially featureless with exception of a weak 0.48-microns spin-forbidden Fe3+ absorption band. The spectrum also has an overall blue slope. The albedo of 2008 EV5 remains uncertain with a lower limit at 0.05 and a higher end at 0.20 based on thermal modeling. The Busch et al. (2011) albedo estimate of 0.12 is consistent with our thermal modeling results. The albedo and composition of 2008 EV5 are also consistent with a C-type taxonomic classification (Somers et al. 2008). The best spectral match is with CI carbonaceous chondrites similar to Orgueil, which also have a weak 0.48-microns feature and an overall blue slope. This 0.48-microns feature is also seen in the spectrum of magnetite. The albedo of CI chondrites is at the lower limit of our estimated range for the albedo of 2008 EV5.Comment: Pages: 19 Figures: 6 Tables:

Recent variability of the global ocean carbon sink

We present a new observation-based estimate of the global oceanic carbon dioxide (CO2) sink and its temporal variation on a monthly basis from 1998 through 2011 and at a spatial resolution of 1×1. This sink estimate rests upon a neural network-based mapping of global surface ocean observations of the partial pressure of CO2 (pCO2) from the Surface Ocean CO2 Atlas database. The resulting pCO2 has small biases when evaluated against independent observations in the different ocean basins, but larger randomly distributed differences exist particularly in high latitudes. The seasonal climatology of our neural network-based product agrees overall well with the Takahashi et al. (2009) climatology, although our product produces a stronger seasonal cycle at high latitudes. From our global pCO2 product, we compute a mean net global ocean (excluding the Arctic Ocean and coastal regions) CO2 uptake flux of −1.42 ± 0.53 Pg C yr−1, which is in good agreement with ocean inversion-based estimates. Our data indicate a moderate level of interannual variability in the ocean carbon sink (±0.12 Pg C yr−1, 1𝜎) from 1998 through 2011, mostly originating from the equatorial Pacific Ocean, and associated with the El Nino–Southern Oscillation. Accounting for steady state riverine and Arctic Ocean carbon fluxes our estimate further implies a mean anthropogenic CO2 uptake of −1.99 ± 0.59 Pg C yr−1 over the analysis period. From this estimate plus the most recent estimates for fossil fuel emissions and atmospheric CO2 accumulation, we infer a mean global land sink of −2.82 ± 0.85 Pg C yr−1 over the 1998 through 2011 period with strong interannual variation

The Fab conformations in the solution structure of human IgG4 restricts access to its Fc region: implications for functional activity.

Human IgG4 antibody shows therapeutically-useful properties compared to the IgG1, IgG2 and IgG3 subclasses. Thus IgG4 does not activate complement, and shows conformational variability. These properties are attributable to its hinge region, which is the shortest of the four IgG subclasses. Using high throughput scattering methods, we have studied the solution structure of wild-type IgG4(Ser222) and a hinge mutant IgG4(Pro222) in different buffers and temperatures, where the proline substitution suppresses the formation of half-antibody. Analytical ultracentrifugation showed that both IgG4 forms were principally monomeric with sedimentation coefficients s020,w of 6.6-6.8 S. A monomer-dimer equilibrium was observed in heavy water buffer at low temperature. Scattering showed that the X-ray radius of gyration RG was unchanged with concentration in 50-250 mM NaCl buffers, while the neutron RG values showed a concentration-dependent increase as the temperature decreased in heavy water buffers. The distance distribution curves P(r) revealed two peaks, M1 and M2 that shifted below 2 mg/ml to indicate concentration-dependent IgG4 structures, in addition to IgG4 dimer formation at high concentration in heavy water. Constrained X-ray and neutron scattering modelling revealed asymmetric solution structures for IgG4(Ser222) with extended hinge structures. The IgG4(Pro222) structure was similar. Both IgG4 structures showed that their Fab regions were positioned close enough to the Fc region to restrict C1q binding. Our new molecular models for IgG4 explain its inability to activate complement, and clarifies aspects of its stability and function for therapeutic applications

The solution structure of rabbit IgG accounts for its interactions with the Fc receptor and complement C1q and its conformational stability.

Solution structures for antibodies are critical to understand function and therapeutic applications. The stability of the solution structure of rabbit IgG in different buffers and temperatures was determined by analytical ultracentrifugation and X-ray and neutron scattering. Rabbit IgG showed a principally monomeric species, which is well resolved from small amounts of a dimeric species. The proportion of dimer increased with increased concentration, decreased temperature and heavy water from 8% to 25% in all buffers except for high salt (250 mM NaCl). The Guinier X-ray radius of gyration R(G) likewise increased with concentration in 137 mM NaCl buffer but was unchanged in 250 mM NaCl buffer. The Guinier neutron R(G) values increased as the temperature decreased. The X-ray and neutron distance distribution curves P(r) revealed two peaks, M1 and M2, whose positions did not change with concentration to indicate unchanged structures under all these conditions. The maximum dimension increased with concentration because of dimer formation. Constrained scattering modeling reproducibly revealed very similar asymmetric solution structures for monomeric rabbit IgG in different buffers, in which the Fab-Fc and Fab-Fab pairs were separated by maximally extended hinge structures. The dimer was best modeled by two pairs of Fab regions forming tip-to-tip contacts. The intact rabbit IgG structures explained the ability of its two ligands, the Fc receptor and complement C1q, to bind to the top of its Fc region that is fully accessible and unhindered by the Fab regions

Expert opinion on detecting and treating depression in palliative care: A Delphi study

<p>Abstract</p> <p>Background</p> <p>There is a dearth of data regarding the optimal method of detecting and treating depression in palliative care. This study applied the Delphi method to evaluate expert opinion on choice of screening tool, choice of antidepressant and choice of psychological therapy. The aim was to inform the development of best practice recommendations for the European Palliative Care Research Collaborative clinical practice guideline on managing depression in palliative care.</p> <p>Methods</p> <p>18 members of an international, multi-professional expert group completed a structured questionnaire in two rounds, rating their agreement with proposed items on a scale from 0-10 and annotating with additional comments. The median and range were calculated to give a statistical average of the experts' ratings.</p> <p>Results</p> <p>There was contention regarding the benefits of screening, with 'routine informal asking' (median 8.5 (0-10)) rated more highly than formal screening tools such as the Hospital Anxiety and Depression Scale (median 7.0 (1-10). Mirtazapine (median 9 (7-10) and citalopram (median 9 (5-10) were the considered the best choice of antidepressant and cognitive behavioural therapy (median 9.0 (3-10) the best choice of psychological therapy.</p> <p>Conclusions</p> <p>The range of expert ratings was broad, indicating discordance in the views of experts. Direct comparative data from randomised controlled trials are needed to strengthen the evidence-base and achieve clarity on how best to detect and treat depression in this setting.</p

Sampling uncertainty in gridded sea surface temperature products and Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data

Sea surface temperature (SST) data are often provided as gridded products, typically at resolutions of order 0.05 degrees from satellite observations to reduce data volume at the request of data users and facilitate comparison against other products or models. Sampling uncertainty is introduced in gridded products where the full surface area of the ocean within a grid cell cannot be fully observed because of cloud cover. In this paper we parameterise uncertainties in SST as a function of the percentage of clear-sky pixels available and the SST variability in that subsample. This parameterisation is developed from Advanced Along Track Scanning Radiometer (AATSR) data, but is applicable to all gridded L3U SST products at resolutions of 0.05-0.1 degrees, irrespective of instrument and retrieval algorithm, provided that instrument noise propagated into the SST is accounted for. We also calculate the sampling uncertainty of ~0.04 K in Global Area Coverage (GAC) Advanced Very High Resolution Radiometer (AVHRR) products, using related methods

Transport variability of the Irminger Sea deep western boundary current from a mooring array

The Deep Western Boundary Current in the subpolar North Atlantic is the lower limb of the Atlantic Meridional Overturning Circulation and a key component of the global climate system. Here, a mooring array deployed at 60°N in the Irminger Sea, between 2014 and 2016, provides the longest continuous record of total Deep Western Boundary Current volume transport at this latitude. The 1.8‐year averaged transport of water denser than σθ = 27.8 kg/m3 was −10.8 ± 4.9 Sv (mean ± 1 std; 1 Sv = 106 m3/s). Of this total, we find −4.1 ± 1.4 Sv within the densest layer (σθ > 27.88 kg/m3) that originated from the Denmark Strait Overflow. The lighter North East Atlantic Deep Water layer (σθ = 27.8–27.88 kg/m3) carries −6.5 ± 7.7 Sv. The variability in transport ranges between 2 and 65 days. There is a distinct shift from high to low frequency with distance from the East Greenland slope. High‐frequency fluctuations (2–8 days) close to the continental slope are likely associated with topographic Rossby waves and/or cyclonic eddies. Here, perturbations in layer thickness make a significant (20–60%) contribution to transport variability. In deeper water, toward the center of the Irminger Basin, transport variance at 55 days dominates. Our results suggest that there has been a 1.8 Sv increase in total transport since 2005–2006, but this difference can be accounted for by a range of methodological and data limitation biases

Seasonal and interannual variations of upper ocean heat balance off the west coast of Australia

The Leeuwin Current, a warm, poleward flowing eastern boundary current, dominates the surface circulation off the west coast of Australia and has profound influence on regional marine ecosystem and fisheries recruitment. In this study, the seasonal and interannual variations of upper ocean heat balance in the Leeuwin Current region are analyzed by using an eddy-resolving numerical model simulation, as a first step to quantify the climate impacts on regional ocean thermodynamics and marine ecosystem. The volume transport and heat advection of the Leeuwin Current are stronger during the austral winter on the seasonal cycle and are stronger during a La Nina event on the interannual scale. On both seasonal and interannual timescales, the mixed layer heat budget off the west coast of Australia is predominantly balanced between the variations of the Leeuwin Current heat advection and heat flux across the air-sea interface. On the interannual timescale, the variation of the Leeuwin Current heat advection tends to lead that of the air-sea (latent) heat flux by two months, which is likely a reflection of advection timescales of the Leeuwin Current and its eddy field. The interannual variation of the average February–April sea surface temperature off the west coast of Australia, which is crucial for the larval settlement of western rock lobster, is mostly influenced by the Leeuwin Current heat advection as well as the ocean memory from the previous austral winter, with the air-sea heat exchange playing a buffering role