Quantifying the Impact of Atmospheric Transport Uncertainty on CO2 Surface Flux Estimates.

We show that transport differences between two commonly used global chemical transport models, GEOS-Chem and TM5, lead to systematic space-time differences in modeled distributions of carbon dioxide and sulfur hexafluoride. The distribution of differences suggests inconsistencies between the transport simulated by the models, most likely due to the representation of vertical motion. We further demonstrate that these transport differences result in systematic differences in surface CO2 flux estimated by a collection of global atmospheric inverse models using TM5 and GEOS-Chem and constrained by in situ and satellite observations. While the impact on inferred surface fluxes is most easily illustrated in the magnitude of the seasonal cycle of surface CO2 exchange, it is the annual carbon budgets that are particularly relevant for carbon cycle science and policy. We show that inverse model flux estimates for large zonal bands can have systematic biases of up to 1.7 PgC/year due to large-scale transport uncertainty. These uncertainties will propagate directly into analysis of the annual meridional CO2 flux gradient between the tropics and northern midlatitudes, a key metric for understanding the location, and more importantly the processes, responsible for the annual global carbon sink. The research suggests that variability among transport models remains the largest source of uncertainty across global flux inversion systems and highlights the importance both of using model ensembles and of using independent constraints to evaluate simulated transport.

Hereditary Creutzfeldt-Jakob Disease: A Case Presentation of a Rare Stroke Mimic.

Acute ischemic cerebrovascular accident (CVA) is a time-sensitive emergent diagnosis, requiring rapid diagnosis and consideration of thrombolytic administration. However, a myriad of cerebrovascular mimics creates a diagnostic challenge. A rare CVA mimic is Creutzfeldt-Jakob disease (CJD), a rapidly progressive fatal dementia due to protein misfolding. Magnetic resonance imaging (MRI) and neurology consultation for electroencephalogram (EEG) and specialized cerebrospinal fluid (CSF) studies are diagnostic while the patient is alive. All forms are fatal within months, and diagnosis can be confirmed on postmortem brain testing. While incredibly uncommon, emergency clinicians should consider this diagnosis in the proper patient to advocate for specialized CSF testing and potential palliative care consultation.

A large proportion of North American net ecosystem production is offset by emissions from harvested products, river/stream evasion, and biomass burning.

Diagnostic carbon cycle models produce estimates of net ecosystem production (NEP, the balance of net primary production and heterotrophic respiration) by integrating information from (i) satellite-based observations of land surface vegetation characteristics; (ii) distributed meteorological data; and (iii) eddy covariance flux tower observations of net ecosystem exchange (NEE) (used in model parameterization). However, a full bottom-up accounting of NEE (the vertical carbon flux) that is suitable for integration with atmosphere-based inversion modeling also includes emissions from decomposition/respiration of harvested forest and agricultural products, CO2 evasion from streams and rivers, and biomass burning. Here, we produce a daily time step NEE for North America for the year 2004 that includes NEP as well as the additional emissions. This NEE product was run in the forward mode through the CarbonTracker inversion setup to evaluate its consistency with CO2 concentration observations. The year 2004 was climatologically favorable for NEP over North America and the continental total was estimated at 1730 ± 370 TgC yr(-1) (a carbon sink). Harvested product emissions (316 ± 80 TgC yr(-1) ), river/stream evasion (158 ± 50 TgC yr(-1) ), and fire emissions (142 ± 45 TgC yr(-1) ) counteracted a large proportion (35%) of the NEP sink. Geographic areas with strong carbon sinks included Midwest US croplands, and forested regions of the Northeast, Southeast, and Pacific Northwest. The forward mode run with CarbonTracker produced good agreement between observed and simulated wintertime CO2 concentrations aggregated over eight measurement sites around North America, but overestimates of summertime concentrations that suggested an underestimation of summertime carbon uptake. As terrestrial NEP is the dominant offset to fossil fuel emission over North America, a good understanding of its spatial and temporal variation - as well as the fate of the carbon it sequesters ─ is needed for a comprehensive view of the carbon cycle.

Implementation of an Un-Pairing Passport to Improve the Transition From Intern to Resident During a Critical Period of Anesthesiology Residency Training.

Background: The transition from intern year to the first year of clinical anesthesiology residency (CA-1) is a challenging period for residents and their supervisors. Orientation methods and instructional material targeting this transition vary across U.S. residency programs. An un-pairing passport was implemented during the 2021-2022 transition to guide and provide expectations for interns, senior residents, and staff. The objective of this quality improvement project was to assess the effectiveness of the passport in improving the transition period and overall preparedness of the new CA-1s. Methods: We surveyed 3 groups (CA-1s, CA-2s/CA-3s, and staff anesthesiologists) 6 months after the completion of passport implementation to retrospectively assess the 2021-2022 CA-1 class's preparedness across 7 domains compared with those who transitioned before passport implementation. Mann-Whitney U statistics and median effect sizes were used to compare pre- and postintervention. Results: Self-reflected preparedness scores of the CA-1s were higher across all domains compared with the senior resident group (r = 0.328-0.548). Overall level of comfort and preparedness for the start of the CA-1 year was higher in the postintervention group (r = 0.162- 0.514). Staff anesthesiologists' perceived preparedness of the residents was also higher across all domains for the postintervention group (r = 0.197-0.387). Conclusion: The un-pairing passport improved residents' and staff anesthesiologists' subjective assessments of the readiness of new CA-1 residents after a critical transition in their training. Similar tools can be more broadly applied to other anesthesiology residency and possibly fellowship programs as well as subspecialty rotations within those programs.

An atmospheric perspective on North American carbon dioxide exchange: CarbonTracker.

We present an estimate of net CO(2) exchange between the terrestrial biosphere and the atmosphere across North America for every week in the period 2000 through 2005. This estimate is derived from a set of 28,000 CO(2) mole fraction observations in the global atmosphere that are fed into a state-of-the-art data assimilation system for CO(2) called CarbonTracker. By design, the surface fluxes produced in CarbonTracker are consistent with the recent history of CO(2) in the atmosphere and provide constraints on the net carbon flux independent from national inventories derived from accounting efforts. We find the North American terrestrial biosphere to have absorbed -0.65 PgC/yr (1 petagram = 10(15) g; negative signs are used for carbon sinks) averaged over the period studied, partly offsetting the estimated 1.85 PgC/yr release by fossil fuel burning and cement manufacturing. Uncertainty on this estimate is derived from a set of sensitivity experiments and places the sink within a range of -0.4 to -1.0 PgC/yr. The estimated sink is located mainly in the deciduous forests along the East Coast (32%) and the boreal coniferous forests (22%). Terrestrial uptake fell to -0.32 PgC/yr during the large-scale drought of 2002, suggesting sensitivity of the contemporary carbon sinks to climate extremes. CarbonTracker results are in excellent agreement with a wide collection of carbon inventories that form the basis of the first North American State of the Carbon Cycle Report (SOCCR), to be released in 2007. All CarbonTracker results are freely available at http://carbontracker.noaa.gov.

Psychophysiological Correlates of Attention to Emotional Information in Youth.

Attention to emotional stimuli has been associated with psychological health among adults and youth. In this study, we examined 2 putative functional psychophysiological correlates of attention to emotional information in a community sample of 135 youth (M age=12 years, 7 months; SD age=1 year, 1 month; 50% girls). After measuring resting respiratory sinus arrhythmia (RSA), participants completed a 1,500 ms emotional faces dot probe task with eye tracking. We examined pupil dilation during angry, sad, and happy trials and predicted that lower resting RSA and greater pupil dilation would be associated with relatively greater attention to negative stimuli. Results partially confirmed our hypothesis. Lower resting RSA was associated with relatively greater attention to sad faces. Lower resting RSA was also associated with relatively greater attention to angry faces when pupil dilation was lower. RSA may be an important functional correlate of attention that should be explored further in future research.

Blind prediction of broadband coherence time at basin scales.

A blind comparison with data is made with a model for the coherence time of broadband sound (133 Hz, 17-Hz bandwidth) at 3709 km. Coherence time is limited by changes in the ocean because the acoustic instruments are fixed to the Earth on the bottom of the sea with time bases maintained by atomic clocks. Although the modeled coherence time depends a bit on the difficult problem of correctly modeling relative signal-to-noise ratios, normalized correlation coefficients of the broadband signals for the data (model) are 0.90 (0.83), 0.72 (0.59), and 0.51 (0.36) at lags of 2, 4.1, and 6.2 min, respectively. In all these cases, observed coherence times are a bit longer than modeled. The temporal evolution of the model is based on the linear dispersion relation for internal waves. Acoustic propagation is modeled with the parabolic approximation and the sound-speed insensitive operator.