169 research outputs found
Estimating black carbon aging time-scales with a particle-resolved aerosol model
Understanding the aging process of aerosol particles is important for assessing their chemical reactivity, cloud condensation nuclei activity, radiative properties and health impacts. In this study we investigate the aging of black carbon containing particles in an idealized urban plume using a new approach, the particle-resolved aerosol model PartMC-MOSAIC. We present a method to estimate aging time-scales using an aging criterion based on cloud condensation nuclei activation. The results show a separation into a daytime regime where condensation dominates and a nighttime regime where coagulation dominates. There is also a strong dependence on supersaturation threshold. For the chosen urban plume scenario and supersaturations ranging from 0.1% to 1%, the aging time-scales vary between 11 and 0.068 h during the day, and between 54 and 6.4 h during the night
Flight Operations Analysis Tool
Flight Operations Analysis Tool (FLOAT) is a computer program that partly automates the process of assessing the benefits of planning spacecraft missions to incorporate various combinations of launch vehicles and payloads. Designed primarily for use by an experienced systems engineer, FLOAT makes it possible to perform a preliminary analysis of trade-offs and costs of a proposed mission in days, whereas previously, such an analysis typically lasted months. FLOAT surveys a variety of prior missions by querying data from authoritative NASA sources pertaining to 20 to 30 mission and interface parameters that define space missions. FLOAT provides automated, flexible means for comparing the parameters to determine compatibility or the lack thereof among payloads, spacecraft, and launch vehicles, and for displaying the results of such comparisons. Sparseness, typical of the data available for analysis, does not confound this software. FLOAT effects an iterative process that identifies modifications of parameters that could render compatible an otherwise incompatible mission set
Numerical coupling of aerosol emissions, dry removal, and turbulent mixing in the E3SM Atmosphere Model version 1 (EAMv1), part I: dust budget analyses and the impacts of a revised coupling scheme
An earlier study evaluating the dust life cycle in EAMv1 has revealed that
the simulated global mean dust lifetime is substantially shorter when higher
vertical resolution is used, primarily due to significant strengthening of dust
dry removal in source regions. This paper demonstrates that the sequential
splitting of aerosol emissions, dry removal, and turbulent mixing in the
model's time integration loop, especially the calculation of dry removal after
surface emissions and before turbulent mixing, is the primary reason for the
vertical resolution sensitivity reported in that earlier study. Based on this
reasoning, we propose a simple revision to the numerical process coupling
scheme, which moves the application of the surface emissions to after dry
removal and before turbulent mixing. The revised scheme allows newly emitted
particles to be transported aloft by turbulence before being removed from the
atmosphere, and hence better resembles the dust life cycle in the real world.
Sensitivity experiments are conducted and analyzed to evaluate the impact of
the revised coupling on the simulated aerosol climatology in EAMv1
New Zealand\u27s First Science Satellite Mission
New Zealand has been a space-faring nation since 2017. Rocket Lab USA provides access to orbit for its clients, launching from the east coast of the North island. Joining the select club of nations that can reach space has spurred significant interest in New Zealand’s economic, research and cultural spheres.
As university educators we seek to provide our students with the opportunity to develop the skills necessary to contribute to local and international space economy. We present here an introduction to New Zealand’s first science satellite, APSS-I, and Te Pūnaha Ātea Auckland Space Institute
Community Pharmacy Recruitment for Practice-Based Research: Challenges and Lessons Learned
To support the successful integration of community pharmacies into value-based care models, research on the feasibility and effectiveness of novel pharmacist-provided patient care services is needed. The UNC Eshelman School of Pharmacy, supported by the National Association of Chain Drug Stores (NACDS) Foundation, designed the Community-based Valued-driven Care Initiative (CVCI) to (1) identify effective value-based patient care interventions that could be provided by community pharmacists, (2) implement and evaluate the feasibility of the selected patient care interventions, and (3) develop resources and create collaborative sustainability opportunities. The purpose of this manuscript is to describe recruitment strategies for CVCI and share lessons learned. The project team identified pharmacies for recruitment through a mixed data analysis followed by a “fit” evaluation. A total of 42 pharmacy organizations were identified for recruitment, 24 were successfully contacted, and 9 signed on to the project. During recruitment, pharmacies cited concerns regarding the financial sustainability of implementing and delivering the patient care services, challenges with staffing and infrastructure, and pharmacists’ comfort level. To foster participation, it was vital to have leadership buy-in, clear benefits from implementation, and assured sustainability beyond the research period
Constraining Aging Processes of Black Carbon in the Community Atmosphere Model Using Environmental Chamber Measurements
The direct radiative forcing of black carbon aerosol (BC) on the Earth system remains unsettled, largely due to the uncertainty with physical properties of BC throughout their lifecycle. Here we show that ambient chamber measurements of BC properties provide a novel constraint on the crude BC aging representation in climate models. Observational evidence for significant absorption enhancement of BC can be reproduced when the aging processes in the four‐mode version of the Modal Aerosol Module (MAM4) aerosol scheme in the Community Atmosphere Model version 5 are calibrated by the recent in situ chamber measurements. An observation‐based scaling method is developed in the aging timescale calculation to alleviate the influence of biases in the simulated model chemical composition. Model sensitivity simulations suggest that the different monolayer settings in the BC aging parameterization of MAM4 can cause as large as 26% and 24% differences in BC burden and radiative forcing, respectively. We also find that an increase in coating materials (e.g., sulfate and secondary organic aerosols) reduces BC lifetime by increasing the hygroscopicity of the mixture but enhances its absorption, resulting in a net increase in BC direct radiative forcing. Our results suggest that accurate simulations of BC aging processes as well as other aerosol species are equally important in reducing the uncertainty of BC forcing estimation
Co-ordinated multidisciplinary intervention to reduce time to successful extubation for children on mechanical ventilation: the SANDWICH cluster stepped-wedge RCT
BACKGROUND: Daily assessment of patient readiness for liberation from invasive mechanical ventilation can reduce the duration of ventilation. However, there is uncertainty about the effectiveness of this in a paediatric population.
OBJECTIVES: To determine the effect of a ventilation liberation intervention in critically ill children who are anticipated to have a prolonged duration of mechanical ventilation (primary objective) and in all children (secondary objective).
DESIGN: A pragmatic, stepped-wedge, cluster randomised trial with economic and process evaluations.
SETTING: Paediatric intensive care units in the UK.
PARTICIPANTS: Invasively mechanically ventilated children (aged < 16 years).
INTERVENTIONS: The intervention incorporated co-ordinated multidisciplinary care, patient-relevant sedation plans linked to sedation assessment, assessment of ventilation parameters with a higher than usual trigger for undertaking an extubation readiness test and a spontaneous breathing trial on low levels of respiratory support to test extubation readiness. The comparator was usual care. Hospital sites were randomised sequentially to transition from control to intervention and were non-blinded.
MAIN OUTCOME MEASURES: The primary outcome measure was the duration of invasive mechanical ventilation until the first successful extubation. The secondary outcome measures were successful extubation, unplanned extubation and reintubation, post-extubation use of non-invasive ventilation, tracheostomy, post-extubation stridor, adverse events, length of intensive care and hospital stay, mortality and cost per respiratory complication avoided at 28 days.
RESULTS: The trial included 10,495 patient admissions from 18 paediatric intensive care units from 5 February 2018 to 14 October 2019. In children with anticipated prolonged ventilation (n = 8843 admissions: control, n = 4155; intervention, n = 4688), the intervention resulted in a significantly shorter time to successful extubation [cluster and time-adjusted median difference -6.1 hours (interquartile range -8.2 to -5.3 hours); adjusted hazard ratio 1.11, 95% confidence interval 1.02 to 1.20; p = 0.02] and a higher incidence of successful extubation (adjusted relative risk 1.01, 95% confidence interval 1.00 to 1.02; p = 0.03) and unplanned extubation (adjusted relative risk 1.62, 95% confidence interval 1.05 to 2.51; p = 0.03), but not reintubation (adjusted relative risk 1.10, 95% confidence interval 0.89 to 1.36; p = 0.38). In the intervention period, the use of post-extubation non-invasive ventilation was significantly higher (adjusted relative risk 1.22, 95% confidence interval 1.01 to 1.49; p = 0.04), with no evidence of a difference in intensive care length of stay or other harms, but hospital length of stay was longer (adjusted hazard ratio 0.89, 95% confidence interval 0.81 to 0.97; p = 0.01). Findings for all children were broadly similar. The control period was associated with lower, but not statistically significantly lower, total costs (cost difference, mean £929.05, 95% confidence interval -£516.54 to £2374.64) and significantly fewer respiratory complications avoided (mean difference -0.10, 95% confidence interval -0.16 to -0.03).
LIMITATIONS: The unblinded intervention assignment may have resulted in performance or detection bias. It was not possible to determine which components were primarily responsible for the observed effect. Treatment effect in a more homogeneous group remains to be determined.
CONCLUSIONS: The intervention resulted in a statistically significant small reduction in time to first successful extubation; thus, the clinical importance of the effect size is uncertain.
FUTURE WORK: Future work should explore intervention sustainability and effects of the intervention in other paediatric populations
Ethical, legal, and social issues in the Earth BioGenome Project.
The Earth BioGenome Project (EBP) is an audacious endeavor to obtain whole-genome sequences of representatives from all eukaryotic species on Earth. In addition to the project's technical and organizational challenges, it also faces complicated ethical, legal, and social issues. This paper, from members of the EBP's Ethical, Legal, and Social Issues (ELSI) Committee, catalogs these ELSI concerns arising from EBP. These include legal issues, such as sample collection and permitting; the applicability of international treaties, such as the Convention on Biological Diversity and the Nagoya Protocol; intellectual property; sample accessioning; and biosecurity and ethical issues, such as sampling from the territories of Indigenous peoples and local communities, the protection of endangered species, and cross-border collections, among several others. We also comment on the intersection of digital sequence information and data rights. More broadly, this list of ethical, legal, and social issues for large-scale genomic sequencing projects may be useful in the consideration of ethical frameworks for future projects. While we do not-and cannot-provide simple, overarching solutions for all the issues raised here, we conclude our perspective by beginning to chart a path forward for EBP's work
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New SOA Treatments Within the Energy Exascale Earth System Model (E3SM): Strong Production and Sinks Govern Atmospheric SOA Distributions and Radiative Forcing
Secondary organic aerosols (SOA) are large contributors to fine particle mass loading and number concentration and interact with clouds and radiation. Several processes affect the formation, chemical transformation, and removal of SOA in the atmosphere. For computational efficiency, global models use simplified SOA treatments, which often do not capture the dynamics of SOA formation. Here we test more complex SOA treatments within the global Energy Exascale Earth System Model (E3SM) to investigate how simulated SOA spatial distributions respond to some of the important but uncertain processes affecting SOA formation, removal, and lifetime. We evaluate model predictions with a suite of surface, aircraft, and satellite observations that span the globe and the full troposphere. Simulations indicate that both a strong production (achieved here by multigenerational aging of SOA precursors that includes moderate functionalization) and a strong sink of SOA (especially in the middle upper troposphere, achieved here by adding particle-phase photolysis) are needed to reproduce the vertical distribution of organic aerosol (OA) measured during several aircraft field campaigns; without this sink, the simulated middle upper tropospheric OA is too large. Our results show that variations in SOA chemistry formulations change SOA wet removal lifetime by a factor of 3 due to changes in horizontal and vertical distributions of SOA. In all the SOA chemistry formulations tested here, an efficient chemical sink, that is, particle-phase photolysis, was needed to reproduce the aircraft measurements of OA at high altitudes. Globally, SOA removal rates by photolysis are equal to the wet removal sink, and photolysis decreases SOA lifetimes from 10 to ~3 days. A recent review of multiple field studies found no increase in net OA formation over and downwind biomass burning regions, so we also tested an alternative, empirical SOA treatment that increases primary organic aerosol (POA) emissions near source region and converts POA to SOA with an aging time scale of 1 day. Although this empirical treatment performs surprisingly well in simulating OA loadings near the surface, it overestimates OA loadings in the middle and upper troposphere compared to aircraft measurements, likely due to strong convective transport to high altitudes where wet removal is weak. The default improved model formulation (multigenerational aging with moderate fragmentation and photolysis) performs much better than the empirical treatment in these regions. Differences in SOA treatments greatly affect the SOA direct radiative effect, which ranges from -0.65 (moderate fragmentation and photolysis) to -2 W m-2 (moderate fragmentation without photolysis). Notably, most SOA formulations predict similar global indirect forcing of SOA calculated as the difference in cloud forcing between present-day and preindustrial simulations. © 2020. The Authors
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