The sensitivity of urban canopy air temperature (
Assessment of the global budget of the greenhouse gas nitrous oxide (
 Award ID(s):
 1847687
 Publication Date:
 NSFPAR ID:
 10154824
 Journal Name:
 Proceedings of the National Academy of Sciences
 Volume:
 117
 Issue:
 22
 Page Range or eLocationID:
 p. 1195411960
 ISSN:
 00278424
 Publisher:
 Proceedings of the National Academy of Sciences
 Sponsoring Org:
 National Science Foundation
More Like this

Abstract ) to anthropogenic heat flux ( ${T}_{a}$ ) is known to vary with space and time, but the key factors controlling such spatiotemporal variabilities remain elusive. To quantify the contributions of different physical processes to the magnitude and variability of ${Q}_{AH}$ (where $\mathrm{\Delta}{T}_{a}/\mathrm{\Delta}{Q}_{AH}$ represents a change), we develop a forcingfeedback framework based on the energy budget of air within the urban canopy layer and apply it to diagnosing $\mathrm{\Delta}$ simulated by the Community Land Model Urban over the contiguous United States (CONUS). In summer, the median $\mathrm{\Delta}{T}_{a}/\mathrm{\Delta}{Q}_{AH}$ is around 0.01 $\mathrm{\Delta}{T}_{a}/\mathrm{\Delta}{Q}_{AH}$ over the CONUS. Besides the direct effect of $\text{K\hspace{0.17em}}{\left(\text{W\hspace{0.17em}}{\text{m}}^{\text{2}}\right)}^{1}$ on ${Q}_{AH}$ , there are important feedbacks through changes in the surface temperature, the atmosphere–canopy air heat conductance ( ${T}_{a}$ ), and the surface–canopy air heat conductance. The positive and negative feedbacks nearly cancel each other out and ${c}_{a}$ is mostly controlled by the direct effect in summer. In winter, $\mathrm{\Delta}{T}_{a}/\mathrm{\Delta}{Q}_{AH}$ becomes stronger, with the median value increased by about 20% due to weakened negativemore » $\mathrm{\Delta}{T}_{a}/\mathrm{\Delta}{Q}_{AH}$ 
Abstract We present a Keck/MOSFIRE restoptical composite spectrum of 16 typical gravitationally lensed starforming dwarf galaxies at 1.7 ≲
z ≲ 2.6 (z _{mean}= 2.30), all chosen independent of emissionline strength. These galaxies have a median stellar mass of and a median star formation rate of $\mathrm{log}{({M}_{*}/{M}_{\odot})}_{\mathrm{med}}={8.29}_{0.43}^{+0.51}$ . We measure the faint electrontemperaturesensitive [O ${\mathrm{S}\mathrm{F}\mathrm{R}}_{\mathrm{H}\alpha}^{\mathrm{m}\mathrm{e}\mathrm{d}}={2.25}_{1.26}^{+2.15}\phantom{\rule{0.25em}{0ex}}{M}_{\odot}\phantom{\rule{0.25em}{0ex}}{\mathrm{y}\mathrm{r}}^{1}$iii ]λ 4363 emission line at 2.5σ (4.1σ ) significance when considering a bootstrapped (statisticalonly) uncertainty spectrum. This yields a directmethod oxygen abundance of ( $12+\mathrm{log}{(\mathrm{O}/\mathrm{H})}_{\mathrm{direct}}={7.88}_{0.22}^{+0.25}$ ). We investigate the applicability at high ${0.15}_{0.06}^{+0.12}\phantom{\rule{0.33em}{0ex}}{Z}_{\odot}$z of locally calibrated oxygenbased strongline metallicity relations, finding that the local reference calibrations of Bian et al. best reproduce (≲0.12 dex) our composite metallicity at fixed strongline ratio. At fixedM _{*}, our composite is well represented by thez ∼ 2.3 directmethod stellar mass—gasphase metallicity relation (MZR) of Sanders et al. When comparing to predicted MZRs from the IllustrisTNG and FIRE simulations, having recalculated our stellar masses with more realistic nonparametric star formation histories , we find excellent agreement with the FIRE MZR. Our composite is consistent with no metallicity evolution, atmore » $(\mathrm{log}{({M}_{*}/{M}_{\odot})}_{\mathrm{med}}={8.92}_{0.22}^{+0.31})$ 
The product selectivity of many heterogeneous electrocatalytic processes is profoundly affected by the liquid side of the electrocatalytic interface. The electrocatalytic reduction of CO to hydrocarbons on Cu electrodes is a prototypical example of such a process. However, probing the interactions of surfacebound intermediates with their liquid reaction environment poses a formidable experimental challenge. As a result, the molecular origins of the dependence of the product selectivity on the characteristics of the electrolyte are still poorly understood. Herein, we examined the chemical and electrostatic interactions of surfaceadsorbed CO with its liquid reaction environment. Using a series of quaternary alkyl ammonium cations (
${\mathrm{m}\mathrm{e}\mathrm{t}\mathrm{h}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ ,${\mathrm{e}\mathrm{t}\mathrm{h}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ ,${\mathrm{p}\mathrm{r}\mathrm{o}\mathrm{p}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ , and${\mathrm{b}\mathrm{u}\mathrm{t}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ ), we systematically tuned the properties of this environment. With differential electrochemical mass spectrometry (DEMS), we show that ethylene is produced in the presence of${\mathrm{m}\mathrm{e}\mathrm{t}\mathrm{h}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ and${\mathrm{e}\mathrm{t}\mathrm{h}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ cations, whereas this product is not synthesized in${\mathrm{p}\mathrm{r}\mathrm{o}\mathrm{p}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$  and${\mathrm{b}\mathrm{u}\mathrm{t}\mathrm{y}\mathrm{l}}_{4}{\mathrm{N}}^{+}$ containing electrolytes. Surfaceenhanced infrared absorption spectroscopymore » 
Abstract One of the cornerstone effects in spintronics is spin pumping by dynamical magnetization that is steadily precessing (around, for example, the
z axis) with frequencyω _{0}due to absorption of lowpower microwaves of frequencyω _{0}under the resonance conditions and in the absence of any applied bias voltage. The twodecadesold ‘standard model’ of this effect, based on the scattering theory of adiabatic quantum pumping, predicts that component of spin current vector ${I}^{{S}_{z}}$ is timeindependent while $({I}^{{S}_{x}}(t),{I}^{{S}_{y}}(t),{I}^{{S}_{z}})\propto {\omega}_{0}$ and ${I}^{{S}_{x}}(t)$ oscillate harmonically in time with a single frequency ${I}^{{S}_{y}}(t)$ω _{0}whereas pumped charge current is zero in the same adiabatic $I\equiv 0$ limit. Here we employ more general approaches than the ‘standard model’, namely the timedependent nonequilibrium Green’s function (NEGF) and the Floquet NEGF, to predict unforeseen features of spin pumping: namely precessing localized magnetic moments within a ferromagnetic metal (FM) or antiferromagnetic metal (AFM), whose conduction electrons are exposed to spin–orbit coupling (SOC) of either intrinsic or proximity origin, will pump both spin $\propto {\omega}_{0}$ and charge ${I}^{{S}_{\alpha}}(t)$I (t ) currents. All four of these functions harmonically oscillate in time at both even and odd integer multiples of themore » $N{\omega}_{0}$ 
Climatedriven depletion of ocean oxygen strongly impacts the global cycles of carbon and nutrients as well as the survival of many animal species. One of the main uncertainties in predicting changes to marine oxygen levels is the regulation of the biological respiration demand associated with the biological pump. Derived from the Redfield ratio, the molar ratio of oxygen to organic carbon consumed during respiration (i.e., the respiration quotient,
${r}_{O2:C}$ ) is consistently assumed constant but rarely, if ever, measured. Using a prognostic Earth system model, we show that a 0.1 increase in the respiration quotient from 1.0 leads to a 2.3% decline in global oxygen, a large expansion of lowoxygen zones, additional water column denitrification of 38 Tg N/y, and the loss of fixed nitrogen and carbon production in the ocean. We then present direct chemical measurements of${r}_{O2:C}$ using a Pacific Ocean meridional transect crossing all major surface biome types. The observed${r}_{O2:C}$ has a positive correlation with temperature, and regional mean values differ significantly from Redfield proportions. Finally, an independent global inverse model analysis constrained with nutrients, oxygen, and carbon concentrations supports a positive temperature dependence of${r}_{O2:C}$ in exported organic matter. We provide evidence against the common assumption of a staticmore »