What Can 14CO Measurements Tell Us about OH?

The possible use of 14CO measurements to constrain hydroxyl radical (OH) concentrations in the atmosphere is investigated. 14CO is mainly produced in the upper atmosphere from cosmic radiation. Measurements of 14CO at the surface show lower concentrations compared to the upper atmospheric source region, which is the result of oxidation by OH. In this paper, the sensitivity of 14CO mixing ratio surface measurements to the 3-D OH distribution is assessed with the TM5 model. Simulated 14CO mixing ratios agree within a few molecules 14COcm-3 (STP) with existing measurements at five locations worldwide. The simulated cosmogenic 14CO distribution appears mainly sensitive to the assumed upper atmospheric 14C source function, and to a lesser extend to model resolution. As a next step, the sensitivity of 14CO measurements to OH is calculated with the adjoint TM5 model. The results indicate that 14CO measurements taken in the tropics are sensitive to OH in a spatially confined region that varies strongly over time due to meteorological variability. Given measurements with an accuracy of 0.5 molecules 14COcm-3 STP, a good characterization of the cosmogenic 14CO fraction, and assuming perfect transport modeling, a single 14CO measurement may constrain OH to 0.2¿0.3×106 moleculesOHcm-3 on time scales of 6 months and spatial scales of 70×70 degrees (latitude×longitude) between the surface and 500 hPa. The sensitivity of 14CO measurements to high latitude OH is about a factor of five higher. This is in contrast with methyl chloroform (MCF) measurements, which show the highest sensitivity to tropical OH, mainly due to the temperature dependent rate constant of the MCF¿OH reaction. A logical next step will be the analysis of existing 14CO measurements in an inverse modeling framework. This paper presents the required mathematical framework for such an analysis.JRC.H.2-Climate chang

Rationale for a Permanent Seismic Network in the U.S. Central Plains Utilizing USArray

The eastern two thirds of the coterminous United States (from the Rocky Mountain Front to the east coast) are sparsely equipped with seismic monitoring instruments, with the number of permanent broadband seismic stations per unit area of the order of 5–10% of that in the western U.S. orogenic zone. In this Forum, we use the Central Plains area (CP)—defined here as the fourstate area including Nebraska, Kansas, Iowa, and Missouri—as an example to argue that a greatly densified permanent seismic network in the stable part of the United States could significantly improve our understanding of the processes that led to the formation and four-dimensional structure of the continental lithosphere. The network would also serve as an excellent facility for longterm earthquake monitoring and for public education and outreach. This issue is timely because a state-of-the-art, uniform network could be established by simply converting a small portion of the portable stations in the ongoing USArray project into permanent ones without affecting the overall progress of the USArray

Exposure-Response Analyses of Asbestos and Lung Cancer Subtypes in a Pooled Analysis of Case-Control Studies

International audienceBACKGROUND:Evidence is limited regarding risk and the shape of the exposure-response curve at low asbestos exposure levels. We estimated the exposure-response for occupational asbestos exposure and assessed the joint effect of asbestos exposure and smoking by sex and lung cancer subtype in general population studies.METHODS:We pooled 14 case-control studies conducted in 1985-2010 in Europe and Canada, including 17,705 lung cancer cases and 21,813 controls with detailed information on tobacco habits and lifetime occupations. We developed a quantitative job-exposure-matrix to estimate job-, time period-, and region-specific exposure levels. Fiber-years (ff/ml-years) were calculated for each subject by linking the matrix with individual occupational histories. We fit unconditional logistic regression models to estimate odds ratios (ORs), 95% confidence intervals (CIs), and trends.RESULTS:The fully adjusted OR for ever-exposure to asbestos was 1.24 (95% CI, 1.18, 1.31) in men and 1.12 (95% CI, 0.95, 1.31) in women. In men, increasing lung cancer risk was observed with increasing exposure in all smoking categories and for all three major lung cancer subtypes. In women, lung cancer risk for all subtypes was increased in current smokers (ORs ~two-fold). The joint effect of asbestos exposure and smoking did not deviate from multiplicativity among men, and was more than additive among women.CONCLUSIONS:Our results in men showed an excess risk of lung cancer and its subtypes at low cumulative exposure levels, with a steeper exposure-response slope in this exposure range than at higher, previously studied levels. (See video abstract at, http://links.lww.com/EDE/B161.)

Author Correction: Identification of multiple risk loci and regulatory mechanisms influencing susceptibility to multiple myeloma

Correction to: Nature Communications; https://doi.org/10.1038/s41467-018-04989-w, published online 13 September 2018

Evidence for Increased Genetic Risk Load for Major Depression in Patients Assigned to Electroconvulsive Therapy

Electroconvulsive therapy (ECT) is the treatment of choice for severe and treatment-resistant depression; disorder severity and unfavorable treatment outcomes are shown to be influenced by an increased genetic burden for major depression (MD). Here, we tested whether ECT assignment and response/nonresponse are associated with an increased genetic burden for major depression (MD) using polygenic risk score (PRS), which summarize the contribution of diseaserelated common risk variants. Fifty-one psychiatric inpatients suffering from a major depressive episode underwent ECT. MD-PRS were calculated for these inpatients and a separate population-based sample (n = 3,547 healthy; n = 426 self-reported depression) based on summary statistics from the Psychiatric Genomics Consortium MDD-working group (Cases: n = 59,851; Controls: n = 113,154). MD-PRS explained a significant proportion of disease status between ECT patients and healthy controls (p = .022, R2 = 1.173%); patients showed higher MD-PRS. MD-PRS in population-based depression self-reporters were intermediate between ECT patients and controls (n.s.). Significant associations between MD-PRS and ECT response (50% reduction in Hamilton depression rating scale scores) were not observed. Our findings indicate that ECT cohorts show an increased genetic burden for MD and are consistent with the hypothesis that treatment-resistant MD patients represent a subgroup with an increased genetic risk for MD. Larger samples are needed to better substantiate these findings

Progressive abandonment and planform changes of the central Platte River in Nebraska, central USA, over historical timeframes

This paper presents data compiled from aerial photography, General Land Office maps (GLOs), and discharge data from the central Platte River in Nebraska that quantify and provide a new understanding of channel evolution and abandonment in a braided stream. Analyses of aerial photographs and GLOs in ArcMap™ show that channel area decreased by an average of 46% from 1938 to 2006 and that channel widths in 1858 were an average of 539% greater than in 2006. Annual discharge during 1942–2006 does not show a clear long-term relationship with the decrease in channel width and area. Rather, stabilization through vegetation of bars and channel banks is cited as the major contributing factor to channel shrinkage and the development of an anabranching system within the boundaries of the 1858 channel. The stabilization of anabranches and the encroachment of vegetation onto banks, abandoned channels, and islands have significantly impacted the riparian ecosystem as mobile sandy bars gradually disappeared. Annual aerial photographs of the Platte River from 1984 to 2001 show that the river responds to year-to-year changes in mean discharge through the formation and disappearance of in-channel features such as medium-size transverse bars, large transverse bars, open channels, exposed channel surfaces, laterally accreted surfaces, and vegetated channel islands. Vegetated channel islands and stable anabranches also increased during 1984–2009. Significant change has also occurred since the beginning of the twentieth century on the Wood River, a local tributary to the Platte River. The Wood River experienced a long-term increase in sinuosity after it occupied the abandoned North Channel of the Platte River, which last experienced major sediment transport 350 ± 50 years ago, according to an optically stimulated luminescence date. The modern Wood River is also superimposed on a prehistoric meandering pattern with significantly greater meander amplitude. We present the first channel abandonment model to account for the gradual abandonment of the Platte River braided stream system and its evolution from a braided to an anabranching system: in stage 1, the channel prominently features macroform bars comprising downstream-migrating foresets; in stage 2, downstream-migrating dunes are deposited over channel bed features; and in stage 3, there is a shift from a braided stream to a stream dominated by anabranches and only channel bed features (e.g., three-dimensional dunes) are present. Our new model characterizes the features expected to be found in abandoned braided channels, as well as more temporary features that form and are destroyed through successive stages of abandonment

Scientific Rationale for a Greatly Densified Permanent Seismic Network in the Central Plains Untilizing USArray

The Central Plains (CP) area of the conterminous U.S. is characterized by a diverse amalgamation of tectonic features developed over the past 2 billion years. Boundaries between three major Precambrian terranes and one of the largest continental rift systems on Earth (the Midcontinent Rift) are located in this area. Preliminary geophysical studies suggest that the mantle transition between the Cenozoic Cordilleran and the \u27stable\u27 North American craton lies within the western part of this area. In addition, some of the greatest historical earthquakes in the conterminous United States have occurred in the New Madrid Seismic Zone in the southeastern CP. Therefore, detailed geoscientific studies of the CP will significantly improve our understanding of: (1) the growth, modification, and destruction of continental lithosphere; (2) the nature of the active-to-stable transitional area in the mantle; and (3) the formation mechanism of intra-continent earthquakes. However, the understanding of basement structure in the CP is rudimentary because it is obscured by sedimentary cover, and is thus greatly dependent on a state of the art permanent broadband seismic network. The lack of damaging historic earthquakes in most of the CP has resulted in fewer seismological research efforts relative to the western US. Over the past several decades, seismology has evolved into a much broader branch of geoscience that examines not only earthquakes, but also the structure and dynamics of the Earth\u27s deep interior using data from permanent stations collected over decades. The detectability of the current sparse seismic network in the area can be greatly improved by converting some of the USArray stations into permanent ones. The greatly-densified permanent seismic network will dramatically improve our capability for studying the velocity, anisotropy, and layered structures of the Earth\u27s crust, mantle and core, detecting small earthquakes, assessing seismic risks, and providing effective education and outreach to the general public. To facilitate such an effort, CPEP (Central Plains Earthscope Partnership) was established in 2007. Currently CPEP involves about 60 geoscientists from four CP states (NE, IA, KS, MO)

MERLIN : A French-German Space Lidar Mission Dedicated to Atmospheric Methane

The MEthane Remote sensing Lidar missioN (MERLIN) aims at demonstrating the spaceborne active measurement of atmospheric methane, a potent greenhouse gas, based on an Integrated Path Differential Absorption (IPDA) nadir-viewing LIght Detecting and Ranging (Lidar) instrument. MERLIN is a joint French and German space mission, with a launch currently scheduled for the timeframe 2021/22. The German Space Agency (DLR) is responsible for the payload, while the platform (MYRIADE Evolutions product line) is developed by the French Space Agency (CNES). The main scientific objective of MERLIN is the delivery of weighted atmospheric columns of methane dry-air mole fractions for all latitudes throughout the year with systematic errors small enough (Peer reviewe