We use TROPOMI (TROPOspheric Monitoring Instrument) tropospheric nitrogen dioxide (NO2) measurements to identify cropland soil nitrogen oxide (NOx = NO + NO2) emissions at daily to seasonal scales in ...the U.S. Southern Mississippi River Valley. Evaluating 1.5 years of TROPOMI observations with a box model, we observe seasonality in local NOx enhancements and estimate maximum cropland soil NOx emissions (15–34 ng N m−2 s−1) early in growing season (May–June). We observe soil NOx pulsing in response to daily decreases in volumetric soil moisture (VSM) as measured by the Soil Moisture Active Passive (SMAP) satellite. Daily NO2 enhancements reach up to 0.8 × 1015 molecules cm−2 4–8 days after precipitation when VSM decreases to ~30%, reflecting emissions behavior distinct from previously defined soil NOx pulse events. This demonstrates that TROPOMI NO2 observations, combined with observations of underlying process controls (e.g., soil moisture), can constrain soil NOx processes from space.
Plain Language Summary
Soils are a known source of atmospheric nitrogen oxides (NOx = NO + NO2), a pollutant that contributes to poor air quality. In cropland regions, where nitrogen‐rich fertilizers are applied to soils, NOx emissions can be significantly enhanced. We use satellite observations of nitrogen dioxide (NO2) from TROPOMI (TROPOspheric Monitoring Instrument) to quantify the soil‐driven contribution to the amount of NOx in the atmosphere in a cropland region in Mississippi, USA. At the daily level, we use TROPOMI measurements together with soil moisture observations from the SMAP (Soil Moisture Active Passive) satellite to show that soil moisture plays an important role in regulating the amount of NOx that cropland soils release. At the seasonal level, we see the largest NOx contribution from soils toward the beginning of the growing season (May–June).
Key Points
Daily TROPOMI data provide new opportunities to observe regional cropland NOx emissions from space
Soil NOx pulsing is identified throughout the growing season with a NOx maximum observed when soils dry to ~30% volumetric soil moisture
Cropland NOx emissions peak at the onset of the growing season as determined by TROPOMI NO2 enhancements and a box model framework
ABSTRACT The K2 Mission uses the Kepler spacecraft to obtain high-precision photometry over 80 day campaigns in the ecliptic plane. The Ecliptic Plane Input Catalog (EPIC) provides coordinates, ...photometry, and kinematics based on a federation of all-sky catalogs to support target selection and target management for the K2 mission. We describe the construction of the EPIC, as well as modifications and shortcomings of the catalog. Kepler magnitudes (Kp) are shown to be accurate to 0.1 mag for the Kepler field, and the EPIC is typically complete to Kp 17 (Kp 19 for campaigns covered by Sloan Digital Sky Survey). We furthermore classify 138,600 targets in Campaigns 1-8 ( 88% of the full target sample) using colors, proper motions, spectroscopy, parallaxes, and galactic population synthesis models, with typical uncertainties for G-type stars of 3% in , 0.3 dex in , 40% in radius, 10% in mass, and 40% in distance. Our results show that stars targeted by K2 are dominated by K-M dwarfs ( 41% of all selected targets), F-G dwarfs ( 36%), and K giants ( 21%), consistent with key K2 science programs to search for transiting exoplanets and galactic archeology studies using oscillating red giants. However, we find significant variation of the fraction of cool dwarfs with galactic latitude, indicating a target selection bias due to interstellar reddening and increased contamination by giant stars near the galactic plane. We discuss possible systematic errors in the derived stellar properties, and differences with published classifications for K2 exoplanet host stars. The EPIC is hosted at the Mikulski Archive for Space Telescopes (MAST): http://archive.stsci.edu/k2/epic/search.php.
The development of scalable sources of non-classical light is fundamental to unlocking the technological potential of quantum photonics. Semiconductor quantum dots are emerging as near-optimal ...sources of indistinguishable single photons. However, their performance as sources of entangled-photon pairs are still modest compared to parametric down converters. Photons emitted from conventional Stranski-Krastanov InGaAs quantum dots have shown non-optimal levels of entanglement and indistinguishability. For quantum networks, both criteria must be met simultaneously. Here, we show that this is possible with a system that has received limited attention so far: GaAs quantum dots. They can emit triggered polarization-entangled photons with high purity (g
(0) = 0.002±0.002), high indistinguishability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity (0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dot entanglement sources in future quantum technologies.
Questions such as Is electronic music the sound of the future? or Does electronic music still have its liberating capacity? or Is electronic music capable of renewing itself? were pivotal for the ...whole exhibition, as explained by Marie-Pauline Martin, Director of the Music Museum in Paris and Laurent Bayle, General Director of the Cité de la Musique-Philharmonie de Paris, in their introduction to the exhibition. The answer to this set of questions was a rich, immersive experience that present...
Classical studies have related the spiking of selected neocortical neurons to behavior, but little is known about activity sampled from the entire neural population. We recorded from neurons selected ...independent of spiking, using cell-attached recordings and two-photon calcium imaging, in the barrel cortex of mice performing an object localization task. Spike rates varied across neurons, from silence to >60 Hz. Responses were diverse, with some neurons showing large increases in spike rate when whiskers contacted the object. Nearly half the neurons discriminated object location; a small fraction of neurons discriminated perfectly. More active neurons were more discriminative. Layer (L) 4 and L5 contained the highest fractions of discriminating neurons (∼63% and 79%, respectively), but a few L2/3 neurons were also highly discriminating. Approximately 13,000 spikes per activated barrel column were available to mice for decision making. Coding of object location in the barrel cortex is therefore highly redundant.
► During tactile localization, 10% of barrel cortex neurons fire ∼50% of all spikes ► Nearly half of all single neurons discriminate object location; coding is redundant ► Cortical layers 4 and 5 discriminate best on average ► Discriminative neurons in layer 2/3 are sparse and include excitatory neurons
Active dendrites provide neurons with powerful processing capabilities. However, little is known about the role of neuronal dendrites in behaviourally related circuit computations. Here we report ...that a novel global dendritic nonlinearity is involved in the integration of sensory and motor information within layer 5 pyramidal neurons during an active sensing behaviour. Layer 5 pyramidal neurons possess elaborate dendritic arborizations that receive functionally distinct inputs, each targeted to spatially separate regions. At the cellular level, coincident input from these segregated pathways initiates regenerative dendritic electrical events that produce bursts of action potential output and circuits featuring this powerful dendritic nonlinearity can implement computations based on input correlation. To examine this in vivo we recorded dendritic activity in layer 5 pyramidal neurons in the barrel cortex using two-photon calcium imaging in mice performing an object-localization task. Large-amplitude, global calcium signals were observed throughout the apical tuft dendrites when active touch occurred at particular object locations or whisker angles. Such global calcium signals are produced by dendritic plateau potentials that require both vibrissal sensory input and primary motor cortex activity. These data provide direct evidence of nonlinear dendritic processing of correlated sensory and motor information in the mammalian neocortex during active sensation.
The Transiting Exoplanet Survey Satellite (TESS) will be conducting a nearly all-sky photometric survey over two years, with a core mission goal to discover small transiting exoplanets orbiting ...nearby bright stars. It will obtain 30 minute cadence observations of all objects in the TESS fields of view, along with two-minute cadence observations of 200,000-400,000 selected stars. The choice of which stars to observe at the two-minute cadence is driven by the need to detect small transiting planets, which leads to the selection of primarily bright, cool dwarfs. We describe the catalogs assembled and the algorithms used to populate the TESS Input Catalog (TIC), including plans to update the TIC with the incorporation of the Gaia second data release in the near future. We also describe a ranking system for prioritizing stars according to the smallest transiting planet detectable, and assemble a Candidate Target List (CTL) using that ranking. We discuss additional factors that affect the ability to photometrically detect and dynamically confirm small planets, and we note additional stellar populations of interest that may be added to the final target list. The TIC is available on the STScI MAST server, and an enhanced CTL is available through the Filtergraph data visualization portal system at the URL http://filtergraph.com/tess_ctl.
Neuronal motor commands, whether generating real or neuroprosthetic movements, are shaped by ongoing sensory feedback from the displacement being produced. Here we asked if cortical stimulation could ...provide artificial feedback during operant conditioning of cortical neurons. Simultaneous two-photon imaging and real-time optogenetic stimulation were used to train mice to activate a single neuron in motor cortex (M1), while continuous feedback of its activity level was provided by proportionally stimulating somatosensory cortex. This artificial signal was necessary to rapidly learn to increase the conditioned activity, detect correct performance, and maintain the learned behavior. Population imaging in M1 revealed that learning-related activity changes are observed in the conditioned cell only, which highlights the functional potential of individual neurons in the neocortex. Our findings demonstrate the capacity of animals to use an artificially induced cortical channel in a behaviorally relevant way and reveal the remarkable speed and specificity at which this can occur.
•All-optical brain-machine-brain interface for neuroprosthetic control•Mice rapidly learn to activate single neurons under optogenetically evoked feedback•Population imaging reveals that learning is restricted to the conditioned neuron•Novel “in cerebro” learning paradigm for neural circuit dissection
Prsa et al. demonstrate that cortical stimulation can provide informative feedback about the current state of a voluntarily modulated neuron. Rapid learning of this artificial paradigm holds promise for its use as a research tool and in neuroprosthetic applications.
Studies of secondary prevention for cardiovascular disease show low fulfilment of guideline-recommended targets. This study explored whether nurse-led follow-up could increase adherence to statins ...over time and reasons for discontinuation. All patients admitted for acute coronary syndrome at Östersund hospital between 2010-2014 were screened for the randomized controlled NAILED-ACS trial. The trial comprises two groups, one with nurse-led annual follow-up and medical titration by telephone to reach set intervention targets and one with usual care. All discontinuations of statins were recorded prospectively for at least 36 months and categorized as avoidable or unavoidable. Kaplan-Meier estimates were conducted for first and permanent discontinuations. Predictors for discontinuation were analysed using multivariate Cox regression, statin type and mean LDL-C at end of follow-up. Female gender was a predictor for discontinuation. Allocation in the intervention group predicted increased risk for a first but decreased risk for permanent discontinuation. A nurse-led telemedical secondary prevention programme in a relatively unselected ACS cohort leads to increased adherence to statins over time, greater percentage on potent treatment and lower LDL-C compared to usual care. An initially increased tendency toward early discontinuation in the intervention group stresses the importance of a longer duration of structured follow-up.
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