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We measured maps of atmospheric water (H2O) and its deuterated form (HDO) across the martian globe, showing strong isotopic anomalies and a significant high deuterium/hydrogen (D/H) enrichment indicative of great water loss. The maps sample the evolution of sublimation from the north polar cap, revealing that the released water has a representative D/H value enriched by a factor of about 7 relative to Earth's ocean [Vienna standard mean ocean water (VSMOW)]. Certain basins and orographic depressions show even higher enrichment, whereas high-altitude regions show much lower values (1 to 3 VSMOW). Our atmospheric maps indicate that water ice in the polar reservoirs is enriched in deuterium to at least 8 VSMOW, which would mean that early Mars (4.5 billion years ago) had a global equivalent water layer at least 137 meters deep.

Comets spend most of their lives at large distances from any star, during which time their interior compositions remain relatively unaltered. Cometary observations can therefore provide direct insight into the chemistry that occurred during their birth at the time of planet formation. To-date, there have been no confirmed observations of parent volatiles (gases released directly from the nucleus) of a comet from any planetary system other than our own. Here we present high-resolution, interferometric observations of 2I/Borisov, the first confirmed interstellar comet, obtained using the Atacama Large Millimeter/ submillimeter Array (ALMA) on 15th-16th December 2019. Our observations reveal emission from hydrogen cyanide (HCN), and carbon monoxide (CO), coincident with the expected position of 2I/Borisov’s nucleus, with production rates Q(HCN) = (7.0 ± 1.1) x 10(exp 23)/s and Q(CO) = (4.4 ± 0.7) x 10(exp 26)/s. While the HCN abundance relative to water (0.06–0.16%) appears similar to that of typical, previously observed comets in our Solar System, the abundance of CO (35–105%) is among the highest observed in any comet within 2 au of the Sun. This shows that 2I/Borisov must have formed in a relatively CO-rich environment — probably beyond the CO ice-line in the very cold, outer regions of a distant protoplanetary accretion disk, as part of a population of small, icy bodies analogous to our Solar System’s own proto-Kuiper Belt.

Previous investigations proved the existence of local density enhancements in Europa’s atmosphere, advancing the idea of a possible origination from water plumes. These measurement strategies, however, were sensitive either to total absorption or atomic emissions, which limited the ability to assess the water content. Here we present direct searches for water vapour on Europa spanning dates from February 2016 to May 2017 with the Keck Observatory. Our global survey at infrared wavelengths resulted in non-detections on 16 out of 17 dates, with upper limits below the water abundances inferred from previous estimates. On one date (26 April 2016) we measured 2,095 ± 658 tonnes of water vapour at Europa’s leading hemisphere. We suggest that the outgassing of water vapour on Europa occurs at lower levels than previously estimated, with only rare localized events of stronger activity. 16 out of 17 spectral observations of Europa, spanning from February 2016 to May 2017, did not see anything, but the one on 26 April 2016 shows evidence of a direct detection of water vapour, compatible with a column density of 1.4 ± 0.4 × 10 19  H 2 O m −2 . Whatever water activity there is on Europa, it is very sporadic.

During its close approach to Earth, comet C/Hyakutake 1996 B2 was observed at extreme ultraviolet and x-ray wavelengths with the Röntgen X-ray Satellite and Rossi X-ray Timing Explorer. The emission morphology was symmetric with respect to a vector from the comet's nucleus toward the sun, but not symmetric around the direction of motion of the comet with respect to interplanetary dust. A slowly varying emission and a large impulsive event that varied on time scales of 1 to 2 hours were observed. An interaction between the comet and the solar wind/solar magnetic field seems to be the most likely mechanism for the observed emission.

In the current paradigm, Oort cloud comets formed in the giant planets' region of the solar nebula, where temperatures and other conditions varied greatly. The measured compositions of four such comets (Halley, Hyakutake, Hale-Bopp, and Lee) are consistent with formation from interstellar ices in the cold nebular region beyond Uranus. The composition of comet C/1999 S4 (LINEAR) differs greatly, which suggests that its ices condensed from processed nebular gas, probably in the Jupiter-Saturn region. Its unusual organic composition may require reevaluation of the prebiotic organic material delivered to the young Earth by comets.

This study conducted human factors risk analyses of a doffing protocol for Ebola-level personal protective equipment to identify and quantify the risk of errors made by healthcare workers, marked with surrogate viruses, while doffing and to predict rates of self-contamination.

The saturated hydrocarbons ethane (C$_2$H$_6$) and methane (CH$_4$) along with carbon monoxide (CO) and water (H$_2$O) were detected in comet C/1996 B2 Hyakutake with the use of high-resolution infrared spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. The inferred production rates of molecular gases from the icy, cometary nucleus (in molecules per second) are 6.4 × 10$^{26}$ for C$_2$H$_6$, 1.2 × 10$^{27}$ for CH$_4$, 9.8 × 10$^{27}$ for CO, and 1.7 × 10$^{29}$ for H$_2$O. An abundance of C$_2$H$_6$ comparable to that of CH$_4$ implies that ices in C/1996 B2 Hyakutake did not originate in a thermochemically equilibrated region of the solar nebula. The abundances are consistent with a kinetically controlled production process, but production of C$_2$H$_6$ by gas-phase ion molecule reactions in the natal cloud core is energetically forbidden. The high C$_2$H$_6$/CH$_4$ ratio is consistent with production of C$_2$H$_6$ in icy grain mantles in the natal cloud, either by photolysis of CH$_4$-rich ice or by hydrogen-addition reactions to acetylene condensed from the gas phase.

Abstract Background The safe removal of personal protective equipment (PPE) can limit transmission of serious communicable diseases, but this process poses challenges to healthcare workers (HCWs). Methods We observed 41 HCWs across 4 Ebola treatment centers in Georgia doffing PPE for simulated patients with serious communicable diseases. Using human factors methodologies, we obtained the details, sequences, and durations of doffing steps; identified the ways each step can fail (failure modes [FMs]); quantified the riskiness of FMs; and characterized the workload of doffing steps. Results Eight doffing steps were common to all hospitals—removal of boot covers, gloves (outer and inner pairs), the outermost garment, the powered air purifying respirator (PAPR) hood, and the PAPR helmet assembly; repeated hand hygiene (eg, with hand sanitizer); and a final handwashing with soap and water. Across hospitals, we identified 256 FMs during the common doffing steps, 61 of which comprised 19 common FMs. Most of these common FMs were above average in their riskiness at each hospital. At all hospitals, hand hygiene, removal of the outermost garment, and removal of boot covers were above average in their overall riskiness. Measurements of workload revealed that doffing steps were often mentally demanding, and this facet of workload correlated most strongly with the effortfulness of a doffing step. Conclusions We systematically identified common points of concern in protocols for doffing high-level PPE. Addressing FMs related to hand hygiene and the removal of the outermost garment, boot covers, and PAPR hood could improve HCW safety when doffing high-level PPE. We identified ways that doffing protocols for high-level personal protective equipment may fail to protect healthcare workers. Hand hygiene, removing the outermost garment, boot covers, and respirator hood harbored the greatest risk and failed in similar ways across different hospitals. Healthcare workers at 4 Ebola treatment centers were observed doffing personal protective equipment for simulated patients with serious communicable diseases. Using human factors methodologies, we identified common points of concern and conclude with potential interventions to alleviate these issues.

BackgroundRelatively little is known about the cognitive processes of healthcare workers that mediate between performance-shaping factors (eg, workload, time pressure) and adherence to infection prevention and control (IPC) practices. We taxonomised the cognitive work involved in IPC practices and assessed its role in how pathogens spread.MethodsForty-two registered nurses performed patient care tasks in a standardised high-fidelity simulation. Afterwards, participants watched a video of their simulation and described what they were thinking, which we analysed to obtain frequencies of macrocognitive functions (MCFs) in the context of different IPC practices. Performance in the simulation was the frequency at which participants spread harmless surrogates for pathogens (bacteriophages). Using a tertiary split, participants were categorised into a performance group: high, medium or low. To identify associations between the three variables—performance groups, MCFs and IPC practices—we used multiblock discriminant correspondence analysis (MUDICA).ResultsMUDICA extracted two factors discriminating between performance groups. Factor 1 captured differences between high and medium performers. High performers monitored the situation for contamination events and mitigated risks by applying formal and informal rules or managing their uncertainty, particularly for sterile technique and cleaning. Medium performers engaged more in future-oriented cognition, anticipating contamination events and planning their workflow, across many IPC practices. Factor 2 distinguished the low performers from the medium and high performers who mitigated risks with informal rules and sacrificed IPC practices when managing tradeoffs, all in the context of minimising cross-contamination from physical touch.ConclusionsTo reduce pathogen transmission, new approaches to training IPC (eg, cognitive skills training) and system design are needed. Interventions should help nurses apply their knowledge of IPC fluidly during patient care, prioritising and monitoring situations for risks and deciding how to mitigate risks. Planning IPC into one’s workflow is beneficial but may not account for the unpredictability of patient care.

In simulations of Ebola-level personal protective equipment doffing with experienced healthcare workers, hands, inner gloves, and scrubs are contaminated with nonenveloped viruses and, infrequently, with enveloped viruses.