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The global annual mean contrail climate forcing may exceed that of aviation's cumulative CO2 emissions. As only 2 %–3 % of all flights are likely responsible for 80 % of the global annual contrail energy forcing (EFcontrail), re-routing these flights could reduce the occurrence of strongly warming contrails. Here, we develop a contrail forecasting tool that produces global maps of persistent contrail formation and their EFcontrail formatted to align with standard weather and turbulence forecasts for integration into existing flight planning and air traffic management workflows. This is achieved by extending the existing trajectory-based contrail cirrus prediction model (CoCiP), which simulates contrails formed along flight paths, to a grid-based approach that initializes an infinitesimal contrail segment at each point in a 4D spatiotemporal grid and tracks them until their end of life. Outputs are provided for N aircraft-engine groups, with groupings based on similarities in aircraft mass and engine particle number emissions: N=7 results in a 3 % mean error between the trajectory- and grid-based CoCiP, while N=3 facilitates operational simplicity but increases the mean error to 13 %. We use the grid-based CoCiP to simulate contrails globally using 2019 meteorology and compare its forecast patterns with those from previous studies. Two approaches are proposed to apply these forecasts for contrail mitigation: (i) monetizing EFcontrail and including it as an additional cost parameter within a flight trajectory optimizer or (ii) constructing polygons to avoid airspace volumes with strongly warming contrails. We also demonstrate a probabilistic formulation of the grid-based CoCiP by running it with ensemble meteorology and excluding grid cells with significant uncertainties in the simulated EFcontrail. This study establishes a working standard for incorporating contrail mitigation into flight management protocols and demonstrates how forecasting uncertainty can be incorporated to minimize unintended consequences associated with increased CO2 emissions from re-routes. [ABSTRACT FROM AUTHOR]

Observations of contrails are vital for improving our understanding of the contrail formation and life cycle, informing models, and assessing mitigation strategies. Here, we developed a methodology that utilises ground-based cameras for tracking and analysing young contrails (< 35 min) formed under clear-sky conditions, comparing these observations against reanalysis meteorology and simulations from the contrail cirrus prediction model (CoCiP) with actual flight trajectories. Our observations consist of 14 h of video footage recorded over 5 different days in Central London, capturing 1582 flight waypoints from 281 flights. The simulation correctly predicted contrail formation and absence for around 75 % of these waypoints, with incorrect contrail predictions occurring at warmer temperatures than those with true-positive predictions (7.8 K vs. 12.8 K below the Schmidt–Appleman criterion threshold temperature). When evaluating contrails with observed lifetimes of at least 2 min , the simulation's correct prediction rate for contrail formation increases to over 85 %. Among all waypoints with contrail observations, 78 % of short-lived contrails (observed lifetimes < 2 min) formed under ice-subsaturated conditions, whereas 75 % of persistent contrails (observed lifetimes > 10 min) formed under ice-supersaturated conditions. On average, the simulated contrail geometric width was around 100 m smaller than the observed (visible) width over its observed lifetime, with the mean underestimation reaching up to 280 m within the first 5 min. Discrepancies between the observed and simulated contrail formation, lifetime, and width can be associated with uncertainties in reanalysis meteorology due to known model limitations and sub-grid-scale variabilities, contrail model simplifications, uncertainties in aircraft performance estimates, and observational challenges, among other possible factors. Overall, this study demonstrates the potential of ground-based cameras to create essential observational and benchmark datasets for validating and improving existing weather and contrail models. [ABSTRACT FROM AUTHOR]

Background: Splenic artery embolization (SAE) is increasingly favored for adult blunt splenic injury management. We compared SAE to other splenic injury management strategies using robust statistical techniques. Materials and methods: Univariate analyses of demographics and outcomes were performed for four patient groups: observation, SAE, splenic surgery, splenic surgery + SAE in the American College of Surgeons Trauma Quality Program (TQIP) database. To address nonlinear associations of ED vital signs with mortality, multivariable spline-based logistic regression models with interaction terms between hemodynamic status and management strategy and either splenic Abbreviated Injury Score (AIS) or Injury Severity Score (ISS), were generated. Results: In 44,187 splenic injury patients meeting study inclusion criteria, the most common management strategy was observation alone (77.9%). The observation group had median spleen AIS of 2, ISS 20, with 6.3% mortality; SAE (2.6%) had median spleen AIS3, ISS 24, with 6.6% mortality; splenic surgery (22.4%) AIS4, ISS 29, with 15.4% mortality; and splenic surgery + SAE (0.04%) AIS4, ISS 29, with 15.2% mortality. In multivariable models, SAE had lower predicted probability of mortality than surgery over most initial ED systolic blood pressures (SBPs). At all spleen AIS, SAE had lower predicted mortality than surgery. SAE had lower mortality than surgery except at very high ISS, where it was comparable. SAE had lower predicted mortality than observation management at spleen AIS≥3. In subgroup analysis of patients without severe multi-system injuries, predicted mortality did not differ by management strategy. Conclusions: SAE is associated with decreased mortality at spleen AIS 3–5. The benefits of SAE appear to be largely for spleen AIS 3–5 in the setting of severe (AIS≥3) multi-system injuries. [ABSTRACT FROM AUTHOR]

The current best-estimate of the global annual mean radiative forcing (RF) attributable to contrail cirrus is thought to be 3 times larger than the RF from aviation's cumulative CO 2 emissions. Here, we simulate the global contrail RF for 2019–2021 using reanalysis weather data and improved engine emission estimates along actual flight trajectories derived from Automatic Dependent Surveillance–Broadcast telemetry. Our 2019 global annual mean contrail net RF (62.1 mW m -2) is 44 % lower than current best estimates for 2018 (111 [33, 189] mW m -2 , 95 % confidence interval). Regionally, the contrail net RF is largest over Europe (876 mW m -2) and the USA (414 mW m -2), while the RF values over East Asia (64 mW m -2) and China (62 mW m -2) are close to the global average, because fewer flights in these regions form persistent contrails resulting from lower cruise altitudes and limited ice supersaturated regions in the subtropics due to the Hadley Circulation. Globally, COVID-19 reduced the flight distance flown and contrail net RF in 2020 (- 43 % and - 56 %, respectively, relative to 2019) and 2021 (- 31 % and - 49 %, respectively) with significant regional variations. Around 14 % of all flights in 2019 formed a contrail with a net warming effect, yet only 2 % of all flights caused 80 % of the annual contrail energy forcing. The spatiotemporal patterns of the most strongly warming and cooling contrail segments can be attributed to flight scheduling, engine particle number emissions, tropopause height, and background radiation fields. Our contrail RF estimates are most sensitive to corrections applied to the global humidity fields, followed by assumptions on the engine particle number emissions, and are least sensitive to radiative heating effects on the contrail plume and contrail–contrail overlapping. Using this sensitivity analysis, we estimate that the 2019 global contrail net RF could range between 34.8 and 74.8 mW m -2. [ABSTRACT FROM AUTHOR]

Aviation emissions that are dispersed into the Earth's atmosphere affect the climate and air pollution, with significant spatiotemporal variation owing to heterogeneous aircraft activity. In this paper, we use historical flight trajectories derived from Automatic Dependent Surveillance–Broadcast (ADS-B) telemetry and reanalysis weather data for 2019–2021 to develop the Global Aviation emissions Inventory based on ADS-B (GAIA). In 2019, 40.2 million flights collectively travelled 61 billion kilometres using 283 Tg of fuel, leading to CO 2 , NO X and non-volatile particulate matter (nvPM) mass and number emissions of 893 Tg, 4.49 Tg, 21.4 Gg and 2.8 × 10 26 respectively. Global responses to COVID-19 led to reductions in the annual flight distance flown and CO 2 and NO X emissions in 2020 (- 43 %, - 48 % and - 50 % respectively relative to 2019) and 2021 (- 31 %, - 41 % and - 43 % respectively), with significant regional variability. Short-haul flights with durations < 3 h accounted for 83 % of all flights but only for 35 % of the 2019 CO 2 emissions, while long-haul flights with durations > 6 h (5 % of all flights) were responsible for 43 % of CO 2 and 49 % of NO X emissions. Globally, the actual flight trajectories flown are, on average, ∼ 5 % greater than the great circle path between the origin and destination airports, but this varies by region and flight distance. An evaluation of 8705 unique flights between London and Singapore showed large variabilities in the flight trajectory profile, fuel consumption and emission indices. GAIA captures the spatiotemporal distribution of aviation activity and emissions and is provided for use in future studies to evaluate the negative externalities arising from global aviation. [ABSTRACT FROM AUTHOR]

Introduction: Exceptional response to therapy is rare in patients with advanced pancreatic cancer. This study explored potential genomic differences between typical and exceptional responses that could confer more favorable biology. Methods: We included exceptional responders and controls with advanced pancreatic cancer from Cleveland Clinic from April 2013 to August 2017. Exceptional responders were defined as patients with an overall survival of more than 18 months for metastatic disease and more than 24 months for locally advanced disease. Clinical data were obtained, and next-generation sequencing was performed. Statistical analyses comparing the 2 groups were performed using descriptive statistics, the Kaplan-Meier method, and the log-rank test. Results: The study comprised 4 exceptional responders and 6 controls. Both groups were well balanced in age, sex, race, and treatment regimens. Exceptional responders had significantly fewer nonsynonymous mutations than controls (2.25 vs 5.17; P = .014). A mutation count of less than 3 was associated with significantly better progression-free survival (17.2 vs 2.3 months; P = .002) and overall survival (29.4 vs 4.6 months; P = .013). Tumor mutational burden did not differ between exceptional responders and controls (4.88 vs 5.70 mut/Mb; P = .39). Conclusion: A lower number of nonsynonymous mutations may correlate with exceptional outcomes in patients with pancreatic cancer. These findings should encourage future studies into genomic signatures of exceptional response. [ABSTRACT FROM AUTHOR]

The global annual mean radiative forcing (RF) attributable to contrail cirrus is comparable to the RF from aviation's cumulative CO2 emissions. Here, we simulate the global contrail climate forcing for 2019-2021 using reanalysis weather data and improved engine emission estimates along actual flight trajectories derived from Automatic Dependent Surveillance-Broadcast telemetry. Our 2019 global annual mean contrail net RF (62.1 mW m-2) is 44% lower than current best estimates for 2018 (111 [33, 189] mW m-2). Regionally, the contrail net RF is largest over Europe (876 mW m-2) and the US (414 mW m-2), while the RF over East Asia (64 mW m-2) and China (62 mW m-2) are close to the global mean value because fewer flights in these regions form contrails as a result of lower cruise altitudes and limited ice supersaturated regions in the subtropics due to the Hadley Circulation. Globally, COVID-19 reduced the flight distance flown and contrail net RF in 2020 (-43% and -56% respectively vs. 2019) and 2021 (-31% and -49% respectively) with significant regional variation. Around 14% of all flights form a contrail with a net warming effect, yet only 2% of all flights account for 80% of the annual contrail energy forcing. The spatiotemporal patterns of the most strongly warming and cooling contrail segments can be attributed to flight scheduling factors, aircraft-engine particle number emissions, tropopause height, background cloud and radiation fields, and albedo. Our contrail RF estimates are most sensitive to corrections applied to the global humidity fields, followed by assumptions on the aircraft-engine particle number emissions, and is least sensitive to radiative heating effects on the contrail plume and contrail-contrail overlapping. Accounting for the sensitivity analysis, we estimate a 2019 global contrail net RF of 62.1 [34.8, 74.8] mW m-2. [ABSTRACT FROM AUTHOR]

Climate impact models of the non- CO 2 emissions of aviation are still subject to significant uncertainties. Condensation trails, or contrails, are one of these non- CO 2 effects. In order to validate the contrail simulation models, a dataset of observations covering the entire lifetime of the contrails will be required, as well as the characteristics of the aircraft which produced them. This study carries on the work on contrail observation from geostationary satellite by proposing a new way to track contrails and identify the flight that produced it using geostationary satellite infrared images, weather data as well as air traffic data. It solves the tracking and the identification problem as one, each process leveraging information from the other to achieve a better overall result. This study is a new step towards a consistent contrail dataset that could be used to validate contrail models. [ABSTRACT FROM AUTHOR]

Aviation emissions that are dispersed into the Earth's atmosphere affect the climate and air pollution, with significant spatiotemporal variation owing to heterogeneous aircraft activity. In this paper, we use historical flight trajectories derived from Automatic Dependent Surveillance–Broadcast (ADS-B) telemetry and reanalysis weather data for 2019–2021 to develop the Global Aviation emissions inventory based on ADS-B (GAIA). In 2019, 40.2 million flights collectively travelled 61 billion kilometres using 283 Tg of fuel, leading to CO2, NOX, non-volatile particulate matter (nvPM) mass and number emissions of 893 Tg, 4.49 Tg, 21.4 Gg, and 2.8×1026, respectively. Global responses to COVID-19 led to reductions in the annual flight distance flown, CO2, and NOX emissions in 2020 (-43 %, -48 % and -50 %, respectively relative to 2019) and 2021 (-31 %, -41 % and -43 %, respectively) with significant regional variability. Short-haul flights with duration < 3 h accounted for 83 % of all flights, yet only for 35 % of the 2019 CO2 emissions, while long-haul flights with duration > 6 h (5 % of all flights) were responsible for t43 % of CO2 and 49 % of NOX emissions. Globally, actual flight trajectories flown are, on average, ~5 % greater than the great-circle path between the origin-destination airport but this varies by region and flight distance. An evaluation of 8,705 unique flights between London and Singapore showed large variabilities in the flight trajectory profile, fuel consumption and emission indices. GAIA captures the spatiotemporal distribution of aviation activity and emissions and is provided for use in future studies to evaluate the negative externalities arising from global aviation. [ABSTRACT FROM AUTHOR]

Around 5 % of anthropogenic radiative forcing (RF) is attributed to aviation CO 2 and non-CO 2 impacts. This paper quantifies aviation emissions and contrail climate forcing in the North Atlantic, one of the world's busiest air traffic corridors, over 5 years. Between 2016 and 2019, growth in CO 2 (+3.13% yr -1) and nitrogen oxide emissions (+4.5 % yr -1) outpaced increases in flight distance (+3.05 % yr -1). Over the same period, the annual mean contrail cirrus net RF (204–280 mW m -2) showed significant inter-annual variability caused by variations in meteorology. Responses to COVID-19 caused significant reductions in flight distance travelled (-66%), CO 2 emissions (-71%) and the contrail net RF (-66%) compared with the prior 1-year period. Around 12 % of all flights in this region cause 80 % of the annual contrail energy forcing, and the factors associated with strongly warming/cooling contrails include seasonal changes in meteorology and radiation, time of day, background cloud fields, and engine-specific non-volatile particulate matter (nvPM) emissions. Strongly warming contrails in this region are generally formed in wintertime, close to the tropopause, between 15:00 and 04:00 UTC, and above low-level clouds. The most strongly cooling contrails occur in the spring, in the upper troposphere, between 06:00 and 15:00 UTC, and without lower-level clouds. Uncertainty in the contrail cirrus net RF (216–238 mW m -2) arising from meteorology in 2019 is smaller than the inter-annual variability. The contrail RF estimates are most sensitive to the humidity fields, followed by nvPM emissions and aircraft mass assumptions. This longitudinal evaluation of aviation contrail impacts contributes a quantified understanding of inter-annual variability and informs strategies for contrail mitigation. [ABSTRACT FROM AUTHOR]