76 research outputs found

    An online air-sea exchange model framework for trace gases powered by machine- learning

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    The ocean emits a wide range of trace gases, such as volatile organic compounds, or sulfur-,nitrogen-, and halogen-containing compounds. Many of these gases play critical roles in the atmosphere, including aerosol and cloud formation, tropospheric and stratospheric ozone budget, as well as the self-cleaning capacity of the atmosphere. Most chemistry-climate models use prescribed oceanic emissions (often derived from observations). These prescribed (offline) emissions generally do not respond to changes in local conditions. A process-level representation of the bi-directional oceanic emissions of trace gases remains challenging, mainly because the ocean biogeochemicalprocesses controlling the natural synthesis of these compounds in the seawater remain poorly understood. We present a new online air-sea exchange framework for the NCAR CESM2, with an observationally trained machine-learning emulator to couple the ocean biogeochemistry with the air-sea exchange. This machine-learning based approach so far has been tested for a number of important trace gases, including dimethyl sulfide (DMS), acetone, bromoform (CHBr 3 ), and dibromomethane (CH 2 Br 2 ), and the preliminary results are evaluated with observations around the globe. This new model framework is more skillful than the widely used top-down approaches for representing the seasonal/spatial variations and the annual means of atmospheric concentrations. The new approach improves the model predictability for the coupled earth system model, and can be used as a basis for investigating the future ocean emissions and feedbacks under climate change.Fil: Wang, Siyuan. National Center for Atmospheric Research; Estados UnidosFil: Emmons, Louisa K.. National Center for Atmospheric Research; Estados UnidosFil: Tilmes, Simone. National Center for Atmospheric Research; Estados UnidosFil: Kinnison, Douglas E.. National Center for Atmospheric Research; Estados UnidosFil: Long, Mateo C.. National Center for Atmospheric Research; Estados UnidosFil: Lamarque, Jean Francoise. National Center for Atmospheric Research; Estados UnidosFil: Apel, Eric C.. National Oceanic & Atmospheric Administration, Esrl; Estados UnidosFil: Hornbrook, Rebecca S.. Centro Nacional de Investigación Atmosférica; Estados UnidosFil: Montzka, Stephen. National Ocean And Atmospheric Administration; Estados UnidosFil: Saiz López, Alfonso. Consejo Superior de Investigaciones Científicas; EspañaFil: Fernandez, Rafael Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Tecnológica Nacional. Facultad Regional de Mendoza; ArgentinaAmerican Geophysical Union Fall MeetingSan FranciscoEstados UnidosAmerican Geophysical Unio

    CAM6-chem with very short-lived halogen chemistry: evaluation with the whole air sampler aircraft data from multiple seasons and locations

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    A new version of the Community Atmosphere Model with chemistry (CAM6-chem) has recently been released to the atmospheric science community (June 2018). CAM6-chem has updated boundary layer processes, shallow convection and liquid cloud macrophysics, and two-moment cloud microphysics with prognostic cloud mass andconcentration. A 4-mode prognostic aerosol representation (MAM4) has been added that includes a representation of dust, sea-salt black carbon, organic carbon, and sulfate in three size categories (Gettelman et al., 2019). CAM6-Chem has a detailed representation of both tropospheric and stratospheric chemistry. The tropospheric chemistry includes updates to the representation the organic nitrates, isoprene oxidization, and the speciation of the aromaticand terpenes (Emmons et al., 2019). This mechanism also includes a comprehensive secondary organic aerosol parameterization based on the Volatility Basic Set (VBS) model framework (Hodzic et al. 2016; Tilmes et al., 2019). The stratospheric halogen chemistry represents the distribution of CH3Cl, CFCs, HCFCs, CH3Br, and halons (Kinnison et al., 2007). For this study, the emissions, wet and dry depositions, and chemical processes that represent Very Short-Lived Halogens (VSLH) were added (e.g., Saiz-Lopez et al., 2016). Evaluation of the organic VSLH distributions are to compare with trace gas measurements collected during seven field campaigns, two withmultiple deployments, to evaluate the model performance over multiple years. The campaigns include HIPPO (2009-2011) pole to pole observations in the Pacific on the NSF/NCAR GV over multiple seasons; SEAC4RS (Aug./Sept., 2013) in the central and southern U.S. and western Gulf of Mexico on the NASA ER-2 and DC8; ATTREX (2011-2015) on the NASA Global Hawk over multiple seasons and locations; CONTRAST (Jan/Feb, 2014) in the western Pacific on the NSF/NCAR GV; VIRGAS (Oct., 2015) in the south central US and western Gulf of Mexico on the NASA WB-57; ORCAS (Jan/Feb, 2016) over the southern ocean on the NSF/NCAR GV; and POSIDON (Oct, 2016) in the western Pacific on the NASA WB-57. The model was ?nudged? to NASA Modern-Era Retrospective analysis for Research and Applications, version 2 meteorological fields to represent the synoptic meteorology for each mission. The analysis will focus on along the flight tracks comparisons with the model and will also examine comparisons of vertical distributions and various tracer-tracer correlations. Implications of this new model version on estimated input of inorganic bromine and iodine into the lower stratosphere will be discussed.Fil: Kinnisson, Douglas E.. National Center for Atmospheric Research; Estados UnidosFil: Saiz Lopez, Alfonso. Consejo Superior de Investigaciones Científicas. Instituto de Química Física "Rocasolano"; EspañaFil: Cuevas, Carlos Alberto. Consejo Superior de Investigaciones Científicas. Instituto de Química Física "Rocasolano"; EspañaFil: Fernandez, Rafael Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: Lamarque, Jean Francoise. National Center for Atmospheric Research; Estados UnidosFil: Tilmes, Simone. National Center for Atmospheric Research; Estados UnidosFil: Emmons, Louisa K.. National Center for Atmospheric Research; Estados UnidosFil: Hodzic, Alma. National Center for Atmospheric Research; Estados UnidosFil: Wang, Siyuan. National Center for Atmospheric Research; Estados UnidosFil: Schauffler, Sue M.. National Center for Atmospheric Research; Estados UnidosFil: Navarro, María. University Of Miami. Rosenstiel School Of Marine Atmospheric Science; Estados UnidosFil: Atlas, Elliot. University Of Miami. Rosenstiel School Of Marine Atmospheric Science; Estados UnidosEGU General Assembly 2019VienaAustriaEuropean Geociences Unio

    A new measure of socio-emotional skills: a pilot study with children, adolescents, and their families

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    Introduction: The teaching of socio-emotional skills has received greater attention, with ongoing theoretical discussions about these competences. Evaluating such characteristics and their development, however, is challenging because of a lack of consensus about theoretical and practical models, the difficulty in analyses that rely solely on self-reports, and the scarcity of robust Brazilian psychometric instruments. Objectives: Therefore, the present study sought to (1) verify the psychometric evidence of the instrument’s internal consistency in assessing socio-emotional skills, (2) identify differences in respondents’ answers, and (3) identify potential issues with questionnaire items via semi-structured interviews. Methods: This pilot study involved 32 responses from children and adolescents and 25 responses from their family members. The questionnaire assessed five socio-emotional skills: self-awareness, self-management, social awareness, relationships, and responsible decision making. Descriptive analyses and Cronbach’s alpha calculations were applied to confirm internal consistency of the items in each subscale. Analyses of variance were also conducted to analyse responses from family members and children. Results: The results showed that self- awareness (α = 0.83, α = 0.76), self-management (α = 0.82, α = 0.79), and relationship skills (α = 0.71, α = 0.79) had adequate internal consistency in both children’s and family members’ versions. Significant differences were observed in scores between family members and children/adolescents in self-awareness (p = 0.0159), self-management (p = 0.0279). Conclusion: The present study underscores the importance and complexity of assessing responsible decision-making skills and suggests that the questionnaire can be useful for evaluating socio-emotional competencies

    Designing organometallic compounds for catalysis and therapy

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    Bioorganometallic chemistry is a rapidly developing area of research. In recent years organometallic compounds have provided a rich platform for the design of effective catalysts, e.g. for olefin metathesis and transfer hydrogenation. Electronic and steric effects are used to control both the thermodynamics and kinetics of ligand substitution and redox reactions of metal ions, especially Ru II. Can similar features be incorporated into the design of targeted organometallic drugs? Such complexes offer potential for novel mechanisms of drug action through incorporation of outer-sphere recognition of targets and controlled activation features based on ligand substitution as well as metal- and ligand-based redox processes. We focus here on η 6-arene, η 5-cyclopentadienyl sandwich and half-sandwich complexes of Fe II, Ru II, Os II and Ir III with promising activity towards cancer, malaria, and other conditions. © 2012 The Royal Society of Chemistry

    An Observationally Constrained Evaluation of the Oxidative Capacity in the Tropical Western Pacific Troposphere

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    Hydroxyl radical (OH) is the main daytime oxidant in the troposphere and determines the atmospheric lifetimes of many compounds. We use aircraft measurements of O3, H2O, NO, and other species from the Convective Transport of Active Species in the Tropics (CONTRAST) field campaign, which occurred in the tropical western Pacific (TWP) during January–February 2014, to constrain a photochemical box model and estimate concentrations of OH throughout the troposphere. We find that tropospheric column OH (OHCOL) inferred from CONTRAST observations is 12 to 40% higher than found in chemical transport models (CTMs), including CAM-chem-SD run with 2014 meteorology as well as eight models that participated in POLMIP (2008 meteorology). Part of this discrepancy is due to a clear-sky sampling bias that affects CONTRAST observations; accounting for this bias and also for a small difference in chemical mechanism results in our empirically based value of OHCOL being 0 to 20% larger than found within global models. While these global models simulate observed O3 reasonably well, they underestimate NOx (NO + NO2) by a factor of two, resulting in OHCOL ~30% lower than box model simulations constrained by observed NO. Underestimations by CTMs of observed CH3CHO throughout the troposphere and of HCHO in the upper troposphere further contribute to differences between our constrained estimates of OH and those calculated by CTMs. Finally, our calculations do not support the prior suggestion of the existence of a tropospheric OH minimum in the TWP, because during January–February 2014 observed levels of O3 and NO were considerably larger than previously reported values in the TWP

    Measurements and Modeling of the Interhemispheric Differences of Atmospheric Chlorinated Very Short-Lived Substances

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    Chlorinated very short-lived substances (Cl-VSLS) are ubiquitous in the troposphere and can contribute to the stratospheric chlorine budget. In this study, we present measurements of atmospheric dichloromethane (CH2Cl2), tetrachloroethene (C2Cl4), chloroform (CHCl3), and 1,2-dichloroethane (1,2-DCA) obtained during the National Aeronautics and Space Administration (NASA) Atmospheric Tomography (ATom) global-scale aircraft mission (2016?2018), and use the Community Earth System Model (CESM) updated with recent chlorine chemistry to further investigate their global tropospheric distribution. The measured global average Cl-VSLS mixing ratios, from 0.2 to 13 km altitude, were 46.6 ppt (CH2Cl2), 9.6 ppt (CHCl3), 7.8 ppt (1,2-DCA), and 0.84 ppt (C2Cl4) measured by the NSF NCAR Trace Organic Analyzer (TOGA) during ATom. Both measurements and model show distinct hemispheric gradients with the mean measured Northern to Southern Hemisphere (NH/SH) ratio of 2 or greater for all four Cl-VSLS. In addition, the TOGA profiles over the NH mid-latitudes showed general enhancements in the Pacific basin compared to the Atlantic basin, with up to ?18 ppt difference for CH2Cl2 in the mid troposphere. We tagged regional source emissions of CH2Cl2 and C2Cl4 in the model and found that Asian emissions dominate the global distributions of these species both at the surface (950 hPa) and at high altitudes (150 hPa). Overall, our results confirm relatively high mixing ratios of Cl-VSLS in the UTLS region and show that the CESM model does a reasonable job of simulating their global abundance but we also note the uncertainties with Cl-VSLS emissions and active chlorine sources in the model. These findings will be used to validate future emission inventories and to investigate the fast convective transport of Cl-VSLS to the UTLS region and their impact on stratospheric ozone

    Posttraumatic Stress Disorder and HIV Risk Among Poor, Inner-City Women Receiving Care in an Emergency Department

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    Objectives. We examined the associations between posttraumatic stress disorder (PTSD) and HIV risk behaviors among a random sample of 241 low-income women receiving care in an urban emergency department. Methods. We recruited participants from the emergency department waiting room during randomly selected 6-hour blocks of time. Multivariate analyses and propensity score weighting were used to examine the associations between PTSD and HIV risk after adjustment for potentially confounding sociodemographic variables, substance use, childhood sexual abuse, and intimate partner violence. Results. A large majority of the sample self-identified as Latina (49%) or African American (44%). Almost one third (29%) of the participants met PTSD criteria. Women who exhibited symptoms in 1 or more PTSD symptom clusters were more likely than women who did not to report having had sex with multiple sexual partners, having had sex with a risky partner, and having experienced partner violence related to condom use in the preceding 6 months. Conclusions. The high rate of PTSD found in this sample and the significant associations between PTSD symptom clusters and partner-related risk behaviors highlight the need to take PTSD into account when designing HIV prevention interventions for low-income, urban women

    Rapid Changes in the Light/Dark Cycle Disrupt Memory of Conditioned Fear in Mice

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    Background: Circadian rhythms govern many aspects of physiology and behavior including cognitive processes. Components of neural circuits involved in learning and memory, e.g., the amygdala and the hippocampus, exhibit circadian rhythms in gene expression and signaling pathways. The functional significance of these rhythms is still not understood. In the present study, we sought to determine the impact of transiently disrupting the circadian system by shifting the light/ dark (LD) cycle. Such ‘‘jet lag’ ’ treatments alter daily rhythms of gene expression that underlie circadian oscillations as well as disrupt the synchrony between the multiple oscillators found within the body. Methodology/Principal Findings: We subjected adult male C57Bl/6 mice to a contextual fear conditioning protocol either before or after acute phase shifts of the LD cycle. As part of this study, we examined the impact of phase advances and phase delays, and the effects of different magnitudes of phase shifts. Under all conditions tested, we found that recall of fear conditioned behavior was specifically affected by the jet lag. We found that phase shifts potentiated the stress-evoked corticosterone response without altering baseline levels of this hormone. The jet lag treatment did not result in overall sleep deprivation, but altered the temporal distribution of sleep. Finally, we found that prior experience of jet lag helps to compensate for the reduced recall due to acute phase shifts. Conclusions/Significance: Acute changes to the LD cycle affect the recall of fear-conditioned behavior. This suggests that

    Association of respiratory symptoms and lung function with occupation in the multinational Burden of Obstructive Lung Disease (BOLD) study

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    Background Chronic obstructive pulmonary disease has been associated with exposures in the workplace. We aimed to assess the association of respiratory symptoms and lung function with occupation in the Burden of Obstructive Lung Disease study. Methods We analysed cross-sectional data from 28 823 adults (≥40 years) in 34 countries. We considered 11 occupations and grouped them by likelihood of exposure to organic dusts, inorganic dusts and fumes. The association of chronic cough, chronic phlegm, wheeze, dyspnoea, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1)/FVC with occupation was assessed, per study site, using multivariable regression. These estimates were then meta-analysed. Sensitivity analyses explored differences between sexes and gross national income. Results Overall, working in settings with potentially high exposure to dusts or fumes was associated with respiratory symptoms but not lung function differences. The most common occupation was farming. Compared to people not working in any of the 11 considered occupations, those who were farmers for ≥20 years were more likely to have chronic cough (OR 1.52, 95% CI 1.19–1.94), wheeze (OR 1.37, 95% CI 1.16–1.63) and dyspnoea (OR 1.83, 95% CI 1.53–2.20), but not lower FVC (β=0.02 L, 95% CI −0.02–0.06 L) or lower FEV1/FVC (β=0.04%, 95% CI −0.49–0.58%). Some findings differed by sex and gross national income. Conclusion At a population level, the occupational exposures considered in this study do not appear to be major determinants of differences in lung function, although they are associated with more respiratory symptoms. Because not all work settings were included in this study, respiratory surveillance should still be encouraged among high-risk dusty and fume job workers, especially in low- and middle-income countries.publishedVersio
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