124 research outputs found
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Agriculture is a major source of NO x pollution in California.
Nitrogen oxides (NO x = NO + NO2) are a primary component of air pollution-a leading cause of premature death in humans and biodiversity declines worldwide. Although regulatory policies in California have successfully limited transportation sources of NO x pollution, several of the United States' worst-air quality districts remain in rural regions of the state. Site-based findings suggest that NO x emissions from California's agricultural soils could contribute to air quality issues; however, a statewide estimate is hitherto lacking. We show that agricultural soils are a dominant source of NO x pollution in California, with especially high soil NO x emissions from the state's Central Valley region. We base our conclusion on two independent approaches: (i) a bottom-up spatial model of soil NO x emissions and (ii) top-down airborne observations of atmospheric NO x concentrations over the San Joaquin Valley. These approaches point to a large, overlooked NO x source from cropland soil, which is estimated to increase the NO x budget by 20 to 51%. These estimates are consistent with previous studies of point-scale measurements of NO x emissions from the soil. Our results highlight opportunities to limit NO x emissions from agriculture by investing in management practices that will bring co-benefits to the economy, ecosystems, and human health in rural areas of California
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Extrapolation of point measurements and fertilizer-only emission factors cannot capture statewide soil NO x emissions.
Maaz et al. argue that inconsistencies across scales of observation undermine our working hypothesis that soil NO x emissions have been substantially overlooked in California; however, the core issues they raise are already discussed in our manuscript. We agree that point measurements cannot be reliably used to estimate statewide soil NO x emissions-the principal motivation behind our new modeling/airplane approach. Maaz et al.'s presentation of fertilizer-based emission factors (a nonmechanistic scaling of point measures to regions based solely on estimated nitrogen fertilizer application rates) includes no data from California or other semiarid sites, and does not explicitly account for widely known controls of climate, soil, and moisture on soil NO x fluxes. In contrast, our model includes all of these factors. Finally, the fertilizer sales data that Maaz et al. highlight are known to suffer from serious errors and do not offer a logically more robust pathway for spatial analysis of NO x emissions from soil
Hegemonic masculinity : just another day at the gym?
This thesis is an examination of masculinity and gym culture in a regional
Canadian community. Through ethnographic observation and in depth interviews I
explore the ways in which masculinity is Hterally embodied in the gym through
participation in weight lifting and interaction with peers. Drawing on research on
masculinity, sociology of the body, and feminist and gender studies, I examine the
social construction of hegemonic masculinity and the extent to which it influences men's
desires to lift weights as well as how it permeates and shapes the gym environments in
which this activity is carried out. In contrast to earHer social science work which focuses
primarily on elite, urban bodybuilders, this study examines the experience of
recreational weight lifters in two distinct gym settings, "hard core gyms" and
"chromed-up health spas" (or health clubs). Comparisons and contrasts in the
construction of masculinity in these two settings are drawn and data is compared with
the experiences of elite bodybuilders described in the earlier studies.
I argue that the experiences of recreational bodybuilders in a regional Canadian
community are different than those of professional bodybuilders. What links these two
different communities together is how hegemonic masculinity affects the men that
work out. Hegemonic masculinity invades gyms in different ways and therefore affects
the men in these gyms in subtly different ways. I have argued throughout this thesis
that the works of Alan Klein (1993) and Samuel Fussell (1991) are useful and necessary,
however, do not account for the range of experiences that men go through well at the
gym
Rapid liquid chromatography–tandem mass spectrometry method for the determination of a broad mixture of pharmaceuticals in surface water
Herein, a new method for the detection of 13 different pharmaceuticals and one metabolite in surface water at low ng/L levels is described. The method utilizes ultra performance liquid chromatography–tandem mass spectrometry and a solid-phase extraction sample preparation. Mean method detection limits were low (4.10 ng/L) and overall solid-phase extraction recovery and reproducibility was adequate (mean recovery, 77.9%; mean RSD, 7.3%). The method allows for quick run times and minimal solvent use as compared with other previously reported high performance
liquid chromatography-based methods. Application of this method for the detection of pharmaceuticals in Tennessee River surfacewater determined
that caffeine, sulfamethoxazole, and carbamazepine were frequently detected (100% of samples). Trimethoprim was moderately detected (30% of samples); acetaminophen, atorvastatin, and lovastatin were infrequently detected (10% of samples); and ciprofloxacin, diltiazem, fluoxetine, levofloxacin, norfluoxetine, ranitidine, and sertraline were not detected. This study reports the first detection of lovastatin in surface water
A review of the stable isotope bio-geochemistry of the global silicon cycle and its associated trace elements
Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry (e.g., Al/Si, Ge/Si, Zn/Si, δ13C, δ15N, δ18O, δ30Si) of dissolved and biogenic Si, present case studies, such as the Silicic Acid Leakage Hypothesis, and discuss challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e., sources, sinks, and processes) and the potential technical and conceptual limitations that need to be considered for future studies.The work by JS was supported by the “Laboratoire d’Excellence”
LabexMER (ANR-10-LABX-19) and co-funded by a grant from
the French government under the program “Investissements
d’Avenir,” and by a grant from the Regional Council of
Brittany (SAD programme). DJC was partially supported by
the Knut and Alice Wallenberg Foundation (KAW Wallenberg
Scholar) and the Swedish Research Council. This review article
has benefited from funding by the European Union Seventh
Framework Programme under grant agreement n◦294146
(project MuSiCC, Marie Curie CIG to DC). GdS is supported
by a Marie Skłodowska-Curie Research Fellowship under
EU Horizon2020 (GA #708407). JuD was supported by the
American Chemical Society Petroleum Research Fund (Grant
# 53798-DNI2). CE acknowledges financial support by the
Institute for Chemistry and Biology of the Marine Environment
(Oldenburg, Germany) and the Max Planck Institute for
Marine Microbiology (Bremen, Germany). KH is funded by
The Royal Society (UF120084) and the European Research
Council (ERC-2015-StG - 678371_ICY-LAB). PG acknowledges
funding by the Collaborative Research Centre 754 “ClimateBiogeochemistry interactions in the Tropical Ocean” (www.
sfb754.de), supported by the Deutsche Forschungsgemeinschaft
(DFG)
Multivariate analysis of FcR-mediated NK cell functions identifies unique clustering among humans and rhesus macaques
Rhesus macaques (RMs) are a common pre-clinical model used to test HIV vaccine efficacy and passive immunization strategies. Yet, it remains unclear to what extent the Fc-Fc receptor (FcR) interactions impacting antiviral activities of antibodies in RMs recapitulate those in humans. Here, we evaluated the FcR-related functionality of natural killer cells (NKs) from peripheral blood of uninfected humans and RMs to identify intra- and inter-species variation. NKs were screened for FcγRIIIa (human) and FcγRIII (RM) genotypes (FcγRIII(a)), receptor signaling, and antibody-dependent cellular cytotoxicity (ADCC), the latter mediated by a cocktail of monoclonal IgG1 antibodies with human or RM Fc. FcγRIII(a) genetic polymorphisms alone did not explain differences in NK effector functionality in either species cohort. Using the same parameters, hierarchical clustering separated each species into two clusters. Importantly, in principal components analyses, ADCC magnitude, NK contribution to ADCC, FcγRIII(a) cell-surface expression, and frequency of phosphorylated CD3ζ NK cells all contributed similarly to the first principal component within each species, demonstrating the importance of measuring multiple facets of NK cell function. Although ADCC potency was similar between species, we detected significant differences in frequencies of NK cells and pCD3ζ+ cells, level of cell-surface FcγRIII(a) expression, and NK-mediated ADCC (P<0.001), indicating that a combination of Fc-FcR parameters contribute to overall inter-species functional differences. These data strongly support the importance of multi-parameter analyses of Fc-FcR NK-mediated functions when evaluating efficacy of passive and active immunizations in pre- and clinical trials and identifying correlates of protection. The results also suggest that pre-screening animals for multiple FcR-mediated NK function would ensure even distribution of animals among treatment groups in future preclinical trials
Path integration over closed loops and Gutzwiller's trace formula
In 1967 M.C. Gutzwiller succeeded to derive the semiclassical expression of
the quantum energy density of systems exhibiting a chaotic Hamiltonian dynamics
in the classical limit. The result is known as the Gutzwiller trace formula.
The scope of this review is to present in a self-contained way recent
developments in functional determinant theory allowing to revisit the
Gutzwiller trace formula in the spirit of field theory.
The field theoretic setup permits to work explicitly at every step of the
derivation of the trace formula with invariant quantities of classical periodic
orbits. R. Forman's theory of functional determinants of linear, non singular
elliptic operators yields the expression of quantum quadratic fluctuations
around classical periodic orbits directly in terms of the monodromy matrix of
the periodic orbits.
The phase factor associated to quadratic fluctuations, the Maslov phase, is
shown to be specified by the Morse index for closed extremals, also known as
Conley and Zehnder index.Comment: Preprint, revised version 132 pages in pdf format. Comments welcom
Exercise for depression in older adults: a meta-analysis of randomized controlled trials adjusting for publication bias
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