Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials

Ice core evidence indicates that even though atmospheric CO2 concentrations did not exceed 300 ppm at any point during the last 800 000 years, East Antarctica was at least 3–4 C warmer than preindustrial (CO2 280 ppm) in each of the last four interglacials. During the previous three interglacials, this anomalous warming was short lived (3000 years) and apparently occurred before the completion of Northern Hemisphere deglaciation. Hereafter, we refer to these periods as “Warmer than Present Transients” (WPTs). We present a series of experiments to investigate the impact of deglacial meltwater on the Atlantic Meridional Overturning Circulation (AMOC) and Antarctic temperature. It is well known that a slowed AMOC would increase southern sea surface temperature (SST) through the bipolar seesaw and observational data suggests that the AMOC remained weak throughout the terminations precedingWPTs, strengthening rapidly at a time which coincides closely with peak Antarctic temperature. We present two 800 kyr transient simulations using the Intermediate Complexity model GENIE-1 which demonstrate that meltwater forcing generates transient southern warming that is consistent with the timing of WPTs, but is not sufficient (in this single parameterisation) to reproduce the magnitude of observed warmth. In order to investigate model and boundary condition uncertainty, we present three ensembles of transient GENIE-1 simulations across Termination II (135 000 to 124 000 BP) and three snapshot HadCM3 simulations at 130 000 BP. Only with consideration of the possible feedback of West Antarctic Ice Sheet (WAIS) retreat does it become possible to simulate the magnitude of observed warming

A model for long-term climatic effects of impacts

We simulated climatic changes following the impacts of asteroids of different sizes on the present surface of Earth. These changes are assumed to be due to the variations of the radiation energy budget as determined by the amount of dust globally distributed in the atmosphere following the impact. A dust evolution model is used to determine the dust particle size spectra as a function of time and atmospheric altitude. We simulate radiation transfer through the dust layer using a multiple scattering calculation scheme and couple the radiative fluxes to an ocean circulation model in order to determine climatic changes and deviations over 2000 years following the impact. Resulting drops in sea surface temperatures are of the order of several degrees at the equator and decrease toward the poles, which is deduced from the increasing importance of infrared insulation of the dust cover at high latitudes. While gravitational settling reduces the atmospheric amount of dust significantly within 6 months, temperature changes remain present for roughly 1 year irrespective of impactor size. Below 1000 m ocean depth, these changes are small, and we do not observe significant modifications in the structure of the ocean circulation pattern. For bodies smaller than 3 km in diameter, climatic effects increase with impactor size. Beyond this threshold, there is enough dust in the atmosphere to block almost completely solar radiation; thus additional dust does not enhance climatic deviations anymore. In fact, owing to interaction in the infrared, we even observe smaller effects by going from a 5 km impactor to larger diameters

Regulations & exemptions during the COVID-19 pandemic for new medical technology, health services & data

The rapid evolution of the COVID-19 pandemic has sparked a large unmet need for new or additional medical technology and healthcare services to be made available urgently. Healthcare, Academic, Government and Industry organizations and individuals have risen to this challenge by designing, developing, manufacturing or implementing innovation. However, both they and healthcare stakeholders are hampered as it is unclear how to introduce and deploy the products of this innovation quickly and legally within the healthcare system. Our paper outlines the key regulations and processes innovators need to comply with, and how these change during a public health emergency via dedicated exemptions. Our work includes references to the formal documents regarding UK healthcare regulation and governance, and is meant to serve as a guide for those who wish to act quickly but are uncertain of the legal and regulatory pathways that allow new a device or service to be fast-tracked

Microbial Morphology and Motility as Biosignatures for Outer Planet Missions

Meaningful motion is an unambiguous biosignature, but because life in the Solar System is most likely to be microbial, the question is whether such motion may be detected effectively on the micrometer scale. Recent results on microbial motility in various Earth environments have provided insight into the physics and biology that determine whether and how microorganisms as small as bacteria and archaea swim, under which conditions, and at which speeds. These discoveries have not yet been reviewed in an astrobiological context. This paper discusses these findings in the context of Earth analog environments and environments expected to be encountered in the outer Solar System, particularly the jovian and saturnian moons. We also review the imaging technologies capable of recording motility of submicrometer-sized organisms and discuss how an instrument would interface with several types of sample-collection strategies