We collected mercury observations as part of the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign over the southeastern US between 1 June and ...15 July 2013. We use the GEOS-Chem chemical transport model to interpret these observations and place new constraints on bromine radical initiated mercury oxidation chemistry in the free troposphere. We find that the model reproduces the observed mean concentration of total atmospheric mercury (THg) (observations: 1.49 ± 0.16 ng m−3, model: 1.51 ± 0.08 ng m−3), as well as the vertical profile of THg. The majority (65 %) of observations of oxidized mercury (Hg(II)) were below the instrument's detection limit (detection limit per flight: 58–228 pg m−3), consistent with model-calculated Hg(II) concentrations of 0–196 pg m−3. However, for observations above the detection limit we find that modeled Hg(II) concentrations are a factor of 3 too low (observations: 212 ± 112 pg m−3, model: 67 ± 44 pg m−3). The highest Hg(II) concentrations, 300–680 pg m−3, were observed in dry (RH < 35 %) and clean air masses during two flights over Texas at 5–7 km altitude and off the North Carolina coast at 1–3 km. The GEOS-Chem model, back trajectories and observed chemical tracers for these air masses indicate subsidence and transport from the upper and middle troposphere of the subtropical anticyclones, where fast oxidation of elemental mercury (Hg(0)) to Hg(II) and lack of Hg(II) removal lead to efficient accumulation of Hg(II). We hypothesize that the most likely explanation for the model bias is a systematic underestimate of the Hg(0) + Br reaction rate. We find that sensitivity simulations with tripled bromine radical concentrations or a faster oxidation rate constant for Hg(0) + Br, result in 1.5–2 times higher modeled Hg(II) concentrations and improved agreement with the observations. The modeled tropospheric lifetime of Hg(0) against oxidation to Hg(II) decreases from 5 months in the base simulation to 2.8–1.2 months in our sensitivity simulations. In order to maintain the modeled global burden of THg, we need to increase the in-cloud reduction of Hg(II), thus leading to faster chemical cycling between Hg(0) and Hg(II). Observations and model results for the NOMADSS campaign suggest that the subtropical anticyclones are significant global sources of Hg(II).
Gene-expression profiling of 574 cases of diffuse large B-cell lymphoma revealed four new subtypes based on the co-occurrence of mutation patterns. The subtypes had prognostic influence beyond the ...usual clinical prognostic factors and may aid in directing targeted therapy.
We present near-infrared (1.0-2.4 km) spectra confirming the youth and cool temperatures of six brown dwarfs and low-mass stars with circumstellar disks toward the Chamaeleon II and Ophiuchus ...star-forming regions. The spectrum of one of our objects indicates a spectral type of 6L1, making it one of the latest spectral type young brown dwarfs identified to date. Comparing spectra of young brown dwarfs, field dwarfs, and giant stars, we define a 1.49--1.56 km H sub(2)O index capable of determining spectral type to c1 subtype, independent of gravity. We have also defined an index based on the 1.14 km sodium feature that is sensitive to gravity, but only weakly dependent on spectral type. Our 1.14 km Na index can be used to distinguish young cluster members ( 5 Myr) from young field dwarfs, both of which may have the triangular H-band continuum shape that persists for at least tens of Myr. Using T sub(eff) values determined from the spectral types of our objects along with luminosities derived from near and mid-infrared photometry, we place our objects on the H-R diagram and overlay evolutionary models to estimate the masses and ages of our young sources. Three of our sources have inferred ages ( 10-30 Myr) that are significantly older than the median stellar age of their parent clouds (1-3 Myr). For these three objects, we derive masses 63 times greater than expected for 1--3 Myr old brown dwarfs with the bolometric luminosities of our sources. The large discrepancies in the inferred masses and ages determined using two separate, yet reasonable, methods emphasize the need for caution when deriving or exploiting brown dwarf mass and age estimates.
Thermal management efforts in nanoscale devices must consider both the thermal properties of the constituent materials and the interfaces connecting them. It is currently unclear whether alloy/alloy ...semiconductor superlattices such as InAlAs/InGaAs have lower thermal conductivities than their constituent alloys. We report measurements of the crossplane thermal resistivity of InAlAs/InGaAs superlattices at room temperature, showing that the superlattice resistivities are larger by a factor of 1.2–1.6 than that of the constituent bulk materials, depending on the strain state and composition. We show that the additional resistance present in these superlattices can be tuned by a factor of 2.5 by altering the lattice mismatch and thereby the phonon-mode mismatch at the interfaces, a principle that is commonly assumed for superlattices but has not been experimentally verified without adding new elements to the layers. We find that the additional resistance in superlattices does not increase significantly when the layer thickness is decreased from 4 to 2 nm. We also report measurements of 250–1000 nm thick films of undoped InGaAs and InAlAs lattice-matched to InP substrates, for there is no published thermal conductivity value for the latter, and we find it to be 2.24 ± 0.09 at 22 °C, which is ∼2.7 times smaller than the widely used estimates.
In 2008 the National Institutes of Health established the Research, Condition and Disease Categorization Database (RCDC) that reports the amount spent by NIH institutes for each disease. Its goal is ...to allow the public "to know how the NIH spends their tax dollars," but it has been little used. The RCDC for 2018 was used to assess 428 schizophrenia-related research projects funded by the National Institute of Mental Health. Three senior psychiatrists independently rated each on its likelihood ("likely", "possible", "very unlikely") of improving the symptoms and/or quality of life for individuals with schizophrenia within 20 years. At least one reviewer rated 386 (90%), and all three reviewers rated 302 (71%), of the research projects as very unlikely to provide clinical improvement within 20 years. Reviewer agreement for the "very unlikely" category was good; for the "possible" category was intermediate; and for the "likely" category was poor. At least one reviewer rated 30 (7%) of the research projects as likely to provide clinical improvement within 20 years. The cost of the 30 projects was 5.5% of the total NIMH schizophrenia-related portfolio or 0.6% of the total NIMH budget. Study results confirm previous 2016 criticisms that the NIMH schizophrenia-related research portfolio disproportionately underfunds clinical research that might help people currently affected. Although the results are preliminary, since the RCDC database has not previously been used in this manner and because of the subjective nature of the assessment, the database would appear to be a useful tool for disease advocates who wish to ascertain how NIH spends its public funds.
Mercury is a global toxin that can be introduced to ecosystems through atmospheric deposition. Mercury oxidation is thought to occur in the free troposphere by bromine radicals, but direct ...observational evidence for this process is currently unavailable. During the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks campaign, we measured enhanced oxidized mercury and bromine monoxide in a free tropospheric air mass over Texas. We use trace gas measurements, air mass back trajectories, and a chemical box model to confirm the origin and chemical history of the sampled air mass. We find the presence of elevated oxidized mercury to be consistent with oxidation of elemental mercury by bromine atoms in this subsiding upper tropospheric air mass within the subtropical Pacific High, where dry atmospheric conditions are conducive to oxidized mercury accumulation. Our results support the role of bromine as the dominant oxidant of mercury in the upper troposphere.
Key Points
We made airborne observations of enhanced oxidized mercury and bromine monoxide
The air mass subsided in the upper troposphere of the subtropical Pacific High
Box modeling supports bromine‐induced mercury oxidation in the free troposphere
Peripheral nerve blockade is used to provide analgesia for patients undergoing total knee arthroplasty. This study compared a single-injection adductor canal block (SACB) with adjuvants to continuous ...adductor canal blockade (CACB). The hypothesis was that the 2 groups would have equivalent analgesia at 30 hours after neural blockade.
This was a double-blinded, randomized, controlled, equivalency trial. Sixty patients were randomized to either the SACB group (20 mL of 0.25% bupivacaine, 1.67 mcg/mL of clonidine, 2 mg of dexamethasone, 150 mcg of buprenorphine, and 2.5 mcg/mL of epinephrine) or the CACB group (20 mL 0.25% of bupivacaine injection with 2.5 mcg/mL of epinephrine followed by an 8 mL/h infusion of 0.125% bupivacaine continued through postoperative day 2). The primary outcome was movement pain scores at 30 hours using the numeric rating scale (NRS). The secondary outcomes included serial postoperative NRS pain scores (rest and movement every 6 hours), opioid consumption, time to first opioid administration, ability to straight leg raise, patient satisfaction, length of stay, and the incidence of nausea/vomiting.
An intention-to-treat analysis included 59 patients. The NRS pain scores with movement were equivalent at 30 hours (SACB 5.5 ± 2.8 vs CACB 5.7 ± 2.9 mean NRS ± standard deviation; mean difference 0.2 −1.5 to 1.0 {90% confidence interval}). All NRS pain scores were equivalent until 42 hours (rest) and 48 hours (rest and movement) with the CACB group having lower pain scores. Other secondary outcomes were not statistically different.
An SACB provides equivalent analgesia for up to 36 hours after block placement when compared with a CACB for patients undergoing total knee arthroplasty, though a CACB was favored at 42 hours and beyond.
We use an ensemble of aircraft, satellite, sonde, and surface observations for April–May 2006 (NASA/INTEX-B aircraft campaign) to better understand the mechanisms for transpacific ozone pollution and ...its implications for North American air quality. The observations are interpreted with a global 3-D chemical transport model (GEOS-Chem). OMI NO2 satellite observations constrain Asian anthropogenic NOx emissions and indicate a factor of 2 increase from 2000 to 2006 in China. Satellite observations of CO from AIRS and TES indicate two major events of Asian transpacific pollution during INTEX-B. Correlation between TES CO and ozone observations shows evidence for transpacific ozone pollution. The semi-permanent Pacific High and Aleutian Low cause splitting of transpacific pollution plumes over the Northeast Pacific. The northern branch circulates around the Aleutian Low and has little impact on North America. The southern branch circulates around the Pacific High and some of that air impacts western North America. Both aircraft measurements and model results show sustained ozone production driven by peroxyacetylnitrate (PAN) decomposition in the southern branch, roughly doubling the transpacific influence from ozone produced in the Asian boundary layer. Model simulation of ozone observations at Mt. Bachelor Observatory in Oregon (2.7 km altitude) indicates a mean Asian ozone pollution contribution of 9±3 ppbv to the mean observed concentration of 54 ppbv, reflecting mostly an enhancement in background ozone rather than episodic Asian plumes. Asian pollution enhanced surface ozone concentrations by 5–7 ppbv over western North America in spring 2006. The 2000–2006 rise in Asian anthropogenic emissions increased this influence by 1–2 ppbv.
Context. The study of variations in total solar irradiance (TSI) is important for understanding how the Sun affects the Earth’s climate. Aims. Full-disk continuum images and magnetograms are now ...available for three full solar cycles. We investigate how modelled TSI compares with direct observations by building a consistent modelled TSI dataset. The model, based only on changes in the photospheric magnetic flux can then be tested on rotational, cyclical and secular timescales. Methods. We use Kitt Peak and SoHO/MDI continuum images and magnetograms in the SATIRE-S model to reconstruct TSI over cycles 21–23. To maximise independence from TSI composites, SORCE/TIM TSI data are used to fix the one free parameter of the model. We compare and combine the separate data sources for the model to estimate an uncertainty on the reconstruction and prevent any additional free parameters entering the model. Results. The reconstruction supports the PMOD composite as being the best historical record of TSI observations, although on timescales of the solar rotation the IRMB composite provides somewhat better agreement. Further to this, the model is able to account for 92% of TSI variations from 1978 to 2009 in the PMOD composite and over 96% during cycle 23. The reconstruction also displays an inter-cycle, secular decline of 0.20+0.12-0.09 W m-2 between cycle 23 minima, in agreement with the PMOD composite. Conclusions. SATIRE-S is able to recreate TSI observations on all timescales of a day and longer over 31 years from 1978. This is strong evidence that changes in photospheric magnetic flux alone are responsible for almost all solar irradiance variations over the last three solar cycles.
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