Deep learning for Chinese NOx emission inversion and the integration of in situ observations: a case study on the COVID-19 pandemic

<p>The COVID-19 pandemic led to the lockdown of over one-third of Chinese cities in early 2020. Observations have shown significant reductions of atmospheric abundances of NO<sub>2</sub> over China during this period. This change in atmospheric NO<sub>2</sub> implies a dramatic change in emission of NO<sub>x</sub>, which provides a unique opportunity to study the response of the chemistry of the atmospheric to large reductions in anthropogenic emissions. We use a deep learning (DL) model to quantify the change in surface emissions of NO<sub>x</sub> in China that are associated with the observed changes in atmospheric NO<sub>2</sub> during the lockdown period. Compared to conventional data assimilation systems, deep neural networks are free of the potential errors associated with parameterized subgrid-scale processes. Furthermore, they are not susceptible to the chemical errors typically found in atmospheric chemical transport models. The neural-network-based approach also offers a more computationally efficient means of inverse modeling of NO<sub>x</sub> emissions at high spatial resolutions. Our DL model is trained using meteorological predictors and reanalysis data of surface NO<sub>2</sub> from 2005 to 2017. The evaluation is conducted using in-situ measurements of NO<sub>2</sub> in 2019 and 2020. The Baidu 'Qianxi' migration data sets are used to evaluate the model's performance in capturing the typical variation in Chinese NOx emissions during the Chinese New Year holidays. The TROPOMI-derived TCR-2 chemical reanalysis is used to evaluate the DL analysis in 2020. We show that the DL-based approach is able to better reproduce the variation in anthropogenic NO<sub>x</sub> emissions and capture the reduction in Chinese NO<sub>x</sub> emissions during the period of the COVID-19 pandemic.</p>

Epigenome-wide associations between observed maternal sensitivity and offspring DNA methylation: a population-based prospective study in children

Background Experimental work in animals has shown that DNA methylation (DNAm), an epigenetic mechanism regulating gene expression, is influenced by typical variation in maternal care. While emerging research in humans supports a similar association, studies to date have been limited to candidate gene and cross-sectional approaches, with a focus on extreme deviations in the caregiving environment. Methods Here, we explored the prospective association between typical variation in maternal sensitivity and offspring epigenome-wide DNAm, in a population-based cohort of children (N = 235). Maternal sensitivity was observed when children were 3- and 4-years-old. DNAm, quantified with the Infinium 450 K array, was extracted at age 6 (whole blood). The influence of methylation quantitative trait loci (mQTLs), DNAm at birth (cord blood), and confounders (socioeconomic status, maternal psychopathology) was considered in follow-up analyses. Results Genome-wide significant associations between maternal sensitivity and offspring DNAm were observed at 13 regions (p < 1.06 × 10−07), but not at single sites. Follow-up analyses indicated that associations at these regions were in part related to genetic factors, confounders, and baseline DNAm levels at birth, as evidenced by the presence of mQTLs at five regions and estimate attenuations. Robust associations with maternal sensitivity were found at four regions, annotated to ZBTB22, TAPBP, ZBTB12, and DOCK4. Conclusions These findings provide novel leads into the relationship between typical variation in maternal caregiving and offspring DNAm in humans, highlighting robust regions of associations, previously implicated in psychological and developmental problems, immune functioning, and stress responses.

Very fast variations of SiO maser emission in evolved stars

Context. Stars on the asymptotic giant branch (AGB) are long-period variables that present strong flux variations at almost all wavelengths, including the SiO maser lines. The periods of these variations are of 300–500 days in Mira-type stars and somewhat shorter in semi-regular variables. The variability of the SiO lines on short timescales has been investigated, but the data are inconclusive. Aims. We aim to study the time evolution of the SiO maser lines in Mira-type and semi-regular variables at short timescales. We also discuss the origin of the observed fast variations. Methods. We observed the SiO maser lines at 7 mm (28SiO v = 1,2 J = 1–0) and 3 mm (28SiO v = 1 J = 2–1) using the 40 m Yebes antenna and the 30 m IRAM telescope, respectively, with a minimum spacing of 1 day. We studied the semi-regular variables RX Boo and RT Vir and the Mira-type variables U Her, R LMi, R Leo, and χ Cyg. We performed a detailed statistical analysis of the variations on different timescales. Results. RX Boo shows strong and fast variations in the intensity of the different spectral features of the SiO lines at 7 and 3 mm. On a timescale of one day, we find variations of ≳10% in 25% of the cases. Variations of greater than ~50% are often found when the observations are separated by 2 or 3 days. A similar variation rate of the SiO lines at 7 mm is found for RT Vir, but the observations of this object are less complete. On the contrary, the variations of the SiO maser line intensity in the Mira-type variables are moderate, with typical variation rates around ≲10% in 7 days. This phenomenon can be explained by the presence of particularly small maser-emitting clumps in semi-regular variables, which would lead to a strong dependence of the intensity on the density variations due to the passage of shocks.

Radon signals in geological (natural) geogas and in a simultaneous enhanced confined mode simulation experiment

An enhanced confined mode (ECM) radon simulation experiment, tested in the laboratory in Jerusalem, was relocated to a subsurface geophysical observatory located 400 km apart, at a depth of 150 m and with a stable temperature. Five gamma sensors are placed around the ECM canister and lead shielding minimizes the influence of natural local gamma radiation. Simultaneous measurement of the geological radon and from radon in the ECM system indicates that the temporal variation of gamma radiation from radon in the ECM system contains annual, multi-day and daily signals, that correspond to signals in the local geological radon. This implies that a common external driver influences the radiation pattern of the geological radon and from radon inside the ECM canister. Once activated at BGO the typical variation pattern of the experimental system occurring in the laboratory changed to that occurring at the observatory. This is interpreted to indicate that the overall style of the temporal patterns of radiation from radon is site dependent. The outcome of this investigation conforms and further substantiates the recent suggestion that a component in solar radiation is driving the annual and daily periodic components in the variation of radon. New geophysical research potential is indicated.

Experimental Determination of the Static Equivalent Pressures of Detonative Explosions of Ethylene/O2/N2-Mixtures and Cyclohexane/O2/N2-Mixtures in Long and Short Pipes

In the recent past (PVP2013-97677, PVP2014-28197, PVP2015-45286, PVP2016-63223) we had started to determine the static equivalent pressures (pstat) of the eight detonative pressure scenarios in long and short pipes for different detonable gas mixtures. The pstat-values are of vital importance for process design: by assigning static equivalent pressures to the highly dynamic detonative pressure peaks it is possible to apply the established pressure vessel guidelines, which can only cope with static loads, in the design of detonation pressure resistant pipes. In the previous publications the parameter R was defined as the ratio between pstat at the location where transition from deflagration to detonation occurs and pstat in the region of the stable detonation. One important finding was that R depends on the reactivity of the gas mixture. So far, R cannot be predicted from first principles or from combustion parameters, but can only be determined experimentally. The ratio R has a special significance, because it not only determines pstat for the Deflagration to Detonation Transition (DDT) in long pipes (first detonative pressure scenario), but also gives a good estimate for two of the three scenarios relevant in the design of short pipes: DDT and the coalescence of DDT and reflection. The present paper concludes the test series conducted at BASF during the last 4 years. It presents additional experimental data showing the variation of R over the entire detonative range of Ethylene/O2/N2 mixtures and along the stoichiometric line of Cyclohexane/O2/N2 mixtures. Based on the variation of R for these ternary mixtures and for the mixtures presented in the preceding publications, a typical variation of R for a general combustible/O2/N2-mixture is estimated over the entire explosive range. By means of this estimation the static equivalent pressures of the six design-relevant detonative pressure scenarios of any combustible/O2/N2-mixture can now be derived combining the parameter R with the Chapman-Jouguet pressure ratio, which can be calculated in a straightforward manner from thermodynamic properties.

Definition of Maintenance Policies in Power Systems Using a Sequential Monte Carlo

This paper reports an application of a simulationmethod called chronological Monte Carlo to evaluate power systems reliability. The Monte Carlo methods are, nowadays, the most widely used method for the estimation of reliability indices. Most of reliability studies that use Monte Carlo simulations are based on a hypothetical situation: the use of a constant failure rate ??. This paper demonstrates a new application that is able to include the typical variation of the failure rate ?? of electrical components that is represented by the well-known bathtub curve and, moreover, is able to show the advantages of different maintenance strategies. The results obtained with the Monte Carlo applications are compared with each other and with a typical Monte Carlo process. The proposed methodologies will be tested in the IEEE RTS-79.

Emended description and resurrection of Kadsura matsudae (Schisandraceae)

The taxonomic identity of Kadsura matsudae is reevaluated. This taxon is often treated as a synonym of K. japonica, a species known from Japan, Korea, and Taiwan. When studying the type materials of K. matsudae, however, we noted that some of its morphological characters, such as the non-contiguous thecae in adjacent stamens, do not fall within the typical variation range of K. japonica. Phylogenetic analysis suggests that although K. matsudae is retrieved within the sect. Kadsura clade, it is not closely related to K. japonica. We therefore propose that K. matsudae should be recognized as a distinct species. Because the protologue of K. matsudae lacks sufficient detail with regards to stamen morphology, which is one of the most important characteristics for identifying the species, we provide an emended description of K. matsudae based on the holotype specimen and newly collected specimens.

Effect of Annealing on Fracture Toughness Evaluation of Ba0.5Sr0.5Co0.8 Fe0.2O3−δ (BSCF) at Different Temperatures

An experimental study on the fracture toughness of BSCF samples were conducted at room temperature as well as elevated temperatures (upto 800°C). The results showed a typical variation of fracture toughness and fracture stress with temperature. It decreased upto 600°C and then increased to reach a comparatively higher value at 800°C. Without annealing the samples showed comparatively higher fracture toughness because of the presence of compressive residual stress.

The Generation of Droplets with Micro-Liter Volume Using Surface Acoustic Wave

We developed a digital micro-fluid generator for the discrete dispensing of bio-samples into a bio-analytical unit on piezoelectric substrate. This micro-fluid device is comprised of a micro-channel, a step and a 1280 yx-LiNbO3 substrate. An ejector jet pump is used for offering a uniform linear velocity. After formed micro-fluid from micro-channel arrives the step, it will be down to the piezoelectric substrate due to its gravity and will be transported by surface acoustic wave (SAW). The micro-fluid generator can generate mono-disperse digital micro-fluid of micro-liter volume relied on the gap between micro-channel and the step. The generation time of digital micro-fluid is about several seconds time, which is also relation to the gap. And the digital micro-fluid generation is repeatable and stable with a typical variation of less than 7% of digital micro-fluid volume. Our digital micro-fluid generator can be effectively applied to biochemical analysis on a piezoelectric substrate.

Sources of Variability in Iso-Inertial Jump Assessments

Purpose:This investigation aimed to quantify the typical variation for kinetic and kinematic variables measured during loaded jump squats.Methods:Thirteen professional athletes performed six maximal effort countermovement jumps on four occasions. Testing occurred over 2 d, twice per day (8 AM and 2 PM) separated by 7 d, with the same procedures replicated on each occasion. Jump height, peak power (PP), relative peak power (RPP), mean power (MP), peak velocity (PV), peak force (PF), mean force (MF), and peak rate of force development (RFD) measurements were obtained from a linear optical encoder attached to a 40 kg barbell.Results:A diurnal variation in performance was observed with afternoon values displaying an average increase of 1.5–5.6% for PP, RPP, MP, PV, PF, and MF when compared with morning values (effect sizes ranging from 0.2–0.5). Day to day reliability was estimated by comparing the morning trials (AM reliability) and the afternoon trials (PM reliability). In both AM and PM conditions, all variables except RFD demonstrated coefficients of variations ranging between 0.8–6.2%. However, for a number of variables (RPP, MP, PV and height), AM reliability was substantially better than PM. PF and MF were the only variables to exhibit a coefficient of variation less than the smallest worthwhile change in both conditions.Discussion:Results suggest that power output and associated variables exhibit a diurnal rhythm, with improved performance in the afternoon. Morning testing may be preferable when practitioners are seeking to conduct regular monitoring of an athlete’s performance due to smaller variability.