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41.
David M. Snider Jason J. Venkiteswaran Sherry L. Schiff John Spoelstra 《Global Change Biology》2012,18(1):356-370
The ability to use δ18O values of nitrous oxide (N2O) to apportion environmental emissions is currently hindered by a poor understanding of the controls on δ18O–N2O from nitrification (hydroxylamine oxidation to N2O and nitrite reduction to N2O). In this study fertilized agricultural soils and unfertilized temperate forest soils were aerobically incubated with different 18O/16O waters, and conceptual and mathematical models were developed to systematically explain the δ18O–N2O formed by nitrification. Modeling exercises used a set of defined input parameters to emulate the measured soil δ18O–N2O data (Monte Carlo approach). The Monte Carlo simulations implied that abiotic oxygen (O) exchange between nitrite (NO2?) and H2O is important in all soils, but that biological, enzyme‐controlled O‐exchange does not occur during the reduction of NO2? to N2O (nitrifier‐denitrification). Similarly, the results of the model simulations indicated that N2O consumption is not characteristic of aerobic N2O formation. The results of this study and a synthesis of the published literature data indicate that δ18O–N2O formed in aerobic environments is constrained between +13‰ and +35‰ relative to Vienna Standard Mean Ocean Water (VSMOW). N2O formed via hydroxylamine oxidation and nitrifier‐denitrification cannot be separated using δ18O unless 18O tracers are employed. The natural range of nitrifier δ18O–N2O is discussed and explained in terms of our conceptual model, and the major and minor controls that define aerobically produced δ18O–N2O are identified. Despite the highly complex nature of δ18O–N2O produced by nitrification this δ18O range is narrow. As a result, in many situations δ18O values may be used in conjunction with δ15N–N2O data to apportion nitrifier‐ and denitrifier‐derived N2O. However, when biological O‐exchange during denitrification is high and N2O consumption is low, there may be too much overlap in δ18O values to distinguish N2O formed by these pathways. 相似文献
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Nusrat Homaira Stephen P. Luby William A. Petri Raija Vainionpaa Mustafizur Rahman Kamal Hossain Cynthia B. Snider Mahmudur Rahman A. S. M. Alamgir Farzina Zesmin Masud Alam Emily S. Gurley Rashid Uz Zaman Tasnim Azim Dean D. Erdman Alicia M. Fry Joseph Bresee Marc-Alain Widdowson Rashidul Haque Eduardo Azziz-Baumgartner 《PloS one》2012,7(2)
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Psychological Distress, Depression, Anxiety, and Burnout among International Humanitarian Aid Workers: A Longitudinal Study 总被引:1,自引:0,他引:1
Barbara Lopes Cardozo Carol Gotway Crawford Cynthia Eriksson Julia Zhu Miriam Sabin Alastair Ager David Foy Leslie Snider Willem Scholte Reinhard Kaiser Miranda Olff Bas Rijnen Winnifred Simon 《PloS one》2012,7(9)
Background
International humanitarian aid workers providing care in emergencies are subjected to numerous chronic and traumatic stressors.Objectives
To examine consequences of such experiences on aid workers'' mental health and how the impact is influenced by moderating variables.Methodology
We conducted a longitudinal study in a sample of international non-governmental organizations. Study outcomes included anxiety, depression, burnout, and life and job satisfaction. We performed bivariate regression analyses at three time points. We fitted generalized estimating equation multivariable regression models for the longitudinal analyses.Results
Study participants from 19 NGOs were assessed at three time points: 212 participated at pre-deployment; 169 (80%) post-deployment; and 154 (73%) within 3–6 months after deployment. Prior to deployment, 12 (3.8%) participants reported anxiety symptoms, compared to 20 (11.8%) at post-deployment (p = 0·0027); 22 (10.4%) reported depression symptoms, compared to 33 (19.5%) at post-deployment (p = 0·0117) and 31 (20.1%) at follow-up (p = .00083). History of mental illness (adjusted odds ratio [AOR] 4.2; 95% confidence interval [CI] 1·45–12·50) contributed to an increased risk for anxiety. The experience of extraordinary stress was a contributor to increased risk for burnout depersonalization (AOR 1.5; 95% CI 1.17–1.83). Higher levels of chronic stress exposure during deployment were contributors to an increased risk for depression (AOR 1·1; 95% CI 1·02–1.20) comparing post- versus pre-deployment, and increased risk for burnout emotional exhaustion (AOR 1.1; 95% CI 1.04–1.19). Social support was associated with lower levels of depression (AOR 0·9; 95% CI 0·84–0·95), psychological distress (AOR = 0.9; [CI] 0.85–0.97), burnout lack of personal accomplishment (AOR 0·95; 95% CI 0·91–0·98), and greater life satisfaction (p = 0.0213).Conclusions
When recruiting and preparing aid workers for deployment, organizations should consider history of mental illness and take steps to decrease chronic stressors, and strengthen social support networks. 相似文献44.
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One Wild Bird at a Time: Portraits of Individual Lives Bernd Heinrich, 2016. Houghton Mifflin Harcourt Publishing Company,New York,NY. ix + 224 pages, 19 B&W line drawings and 8 page color insert. ISBN 9780544387638. $28.00 (Hardcover). Also available as an e‐book.
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Allison Snider 《Journal of Field Ornithology》2017,88(2):206-207
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Christian M. Paumi Matthew Chuk Jamie Snider Igor Stagljar Susan Michaelis 《Microbiology and molecular biology reviews》2009,73(4):577-593
Summary: Members of the ATP-binding cassette (ABC) transporter superfamily exist in bacteria, fungi, plants, and animals and play key roles in the efflux of xenobiotic compounds, physiological substrates, and toxic intracellular metabolites. Based on sequence relatedness, mammalian ABC proteins have been divided into seven subfamilies, ABC subfamily A (ABCA) to ABCG. This review focuses on recent advances in our understanding of ABC transporters in the model organism Saccharomyces cerevisiae. We propose a revised unified nomenclature for the six yeast ABC subfamilies to reflect the current mammalian designations ABCA to ABCG. In addition, we specifically review the well-studied yeast ABCC subfamily (formerly designated the MRP/CFTR subfamily), which includes six members (Ycf1p, Bpt1p, Ybt1p/Bat1p, Nft1p, Vmr1p, and Yor1p). We focus on Ycf1p, the best-characterized yeast ABCC transporter. Ycf1p is located in the vacuolar membrane in yeast and functions in a manner analogous to that of the human multidrug resistance-related protein (MRP1, also called ABCC1), mediating the transport of glutathione-conjugated toxic compounds. We review what is known about Ycf1p substrates, trafficking, processing, posttranslational modifications, regulation, and interactors. Finally, we discuss a powerful new yeast two-hybrid technology called integrated membrane yeast two-hybrid (iMYTH) technology, which was designed to identify interactors of membrane proteins. iMYTH technology has successfully identified novel interactors of Ycf1p and promises to be an invaluable tool in future efforts to comprehensively define the yeast ABC interactome. 相似文献