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Factors affecting recent PM2.5 concentrations in China and South Korea from 2016 to 2020
No full textThis study used observational data and a chemical transport model to investigate the contributions of several factors to the recent change in air quality in China and South Korea from 2016 to 2020. We focused on observational data analysis, which could reflect the annual trend of emission reduction and adjust existing emission amounts to apply it into a chemical transport model. The observation data showed that the particulate matter (PM2.5) concentrations during winter 2020 decreased by ???23.4???% (???14.68?????g/m3) and?????????19.5???% (???5.73?????g/m3) in China and South Korea respectively, compared with that during winter 2016. Meteorological changes, the existing national plan for a long-term emission reduction target, and unexpected events (i.e., Coronavirus disease 2019 (COVID-19) in China and South Korea and the newly introduced special winter countermeasures in South Korea from 2020) are considered major factors that may affect the recent change in air quality. The impact of different meteorological conditions on PM2.5 concentrations was assessed by conducting model simulations by fixing the emission amounts; the results indicated changes of +7.6???% (+4.77?????g/m3) and???+???9.7???% (+2.87?????g/m3) in China and South Korea, respectively, during winter 2020 compared to that during winter 2016. Due to the existing and pre-defined long-term emission control policies implemented in both countries, PM2.5 concentration significantly decreased from winter 2016???2020 in China (???26.0???%; ???16.32?????g/m3) and South Korea (???9.1???%; ???2.69?????g/m3). The unexpected COVID-19 outbreak caused the PM2.5 concentrations in China to decrease during winter 2020 by another ???5.0???% (???3.13?????g/m3). In South Korea, the winter season special reduction policy, which was introduced and implemented in winter 2020, and the COVID-19 pandemic may have contributed to ???19.5???% (???5.92?????g/m3) decrease in PM2.5 concentrations
Multiferroic properties in Fe-site engineered PbFe1/2Nb1/2O3 with distinct antisymmetric spin interaction
No full textMultiferroic Fe-site engineered lead iron niobate [Pb(Fe1/2Nb1/2)O-3, PFN] was prepared by partially substituting Fe with Ni, Co, and Cr, which comprise distinct Bohr magnetons, to investigate the effect of the variation in spin configurations on magnetic and multiferroic properties. All the studied compositions exhibited a single-phase perovskite structure, wherein the lattice constant decreased with increasing substitutions. The inherent ferroelectric order was preserved when Ni or Co ions were introduced, while the introduction of Cr made the samples too lossy, which prevented the verification of the possible ferroelectricity. Substitution of Fe with different transition metals in PFN, which is originally paramagnetic at room temperature, resulted in oriented spin configurations that led to distinct magnetic orders: soft ferromagnetic, hard ferromagnetic, and antiferromagnetic orders for Ni, Co, and Cr, respectively. This distinction mainly stems from the interspin distance and the spin moment, both of which are important factors during the spin exchange interaction. The interspin distance of pristine and Cr-substituted PFN is too long and short, respectively, to induce ferromagnetic properties. Moreover, at room temperature, magnetic-field-dependent magnetoelectric coupling was observed only for the Ni- and Co-substituted PFN owing to their asymmetric spin configuration. This research could lead to a general method for modulating the magnetic properties of multiferroic perovskite oxides
Eutectic salt-assisted planetary centrifugal deagglomeration for single-crystalline cathode synthesis
No full textSingle-crystalline layered cathodes are often desirable for advanced lithium-ion batteries. However, constrained by the accessible temperature range to prevent lithium evaporation, lattice defects and particle agglomerations, the production of single-crystalline cathodes with high phase purity, good electrochemical performance and scalability remains challenging. Here we invent a new mechanochemical activation process that offers a general solution to the conundrum of synthesizing coarse single-crystal cathodes with Li-/Mn-rich or Ni-rich chemistry, which differs from the equipment- and energy-intense and long-duration mechanochemical routes that are difficult to scale up. Our approach is based on interfacial reactive wetting, mediated by transient eutectic salts in situ melted by moderate mechanical agitations, to form a colloidal suspension of nanosized oxides dispersed in liquified lithium salts. It efficiently deagglomerates the polycrystalline precursors, repacks the crystals and homogenizes the lithium-salt distribution, thus enabling facile particle coarsening later into the single-crystalline morphology with improved electrochemical performance. Single-crystalline layered oxides are much sought after as they offer high-performance promises in batteries. Here the authors report a facile and scalable planetary centrifugal mixing technique-aided by eutectic lithium salts-that enables the growth of high-quality single-crystalline cathode materials
A Systematic Review of Anomaly Detection for Business Process Event Logs
No full textWhile a business process is most often executed following a normal path, anomalies may sometimes arise and can be captured in event logs. Event log anomalies stem, for instance, from system malfunctioning or unexpected behavior of human resources involved in a process. To identify and possibly fix these, anomaly detection has emerged recently as a key discipline in process mining. In the paper, the authors present a systematic review of the literature on business process event log anomaly detection. The review aims at selecting systematically studies in the literature that have tackled the issue of event log anomaly detection, classifying existing approaches based on criteria emerging from previous literature reviews, and identifying those research directions in this field that have not been explored extensively. Based on the results of the review, the authors argue that future research should look more specifically into anomaly detection on event streams, extending the number of event log attributes considered to determine anomalies, and producing more standard labeled datasets to benchmark the techniques proposed
Differential Encoding of Trace and Delay Fear Memory in the Entorhinal Cortex
No full textTrace fear conditioning is characterized by a stimulus-free trace interval (TI) between the conditioned stimulus (CS) and the unconditioned stimu- lus (US), which requires an array of brain structures to support the formation and storage of associative memory. The entorhinal cortex (EC) has been proposed to provide essential neural code for resolving temporal discontinuity in conjunction with the hippocampus. However, how the CS and TI are encoded at the neuronal level in the EC is not clear. In Exp. 1, we tested the effect of bilateral pre-training electrolytic lesions of EC on trace vs. delay fear conditioning using rats as subjects. We found that the lesions impaired the acquisition of trace but not delay fear conditioning confirming that EC is a critical brain area for trace fear memory formation. In Exp. 2, single-unit activities from EC were recorded during the pre - training baseline and post-training retention sessions following trace or delay conditioning. The recording results showed that a significant propor- tion of the EC neurons modulated their firing during TI after the trace conditioning, but not after the delay fear conditioning. Further analysis re- vealed that the majority of modulated units decreased the firing rate during the TI or the CS. Taken together, these results suggest that EC critically contributes to trace fear conditioning by modulating neuronal activity during the TI to facilitate the association between the CS and US across a temporal gap
Production of polyhydroxyalkanoates by the thermophile Cupriavidus cauae PHS1
No full textThermophilic production of polyhydroxyalkanoate is considered a very promising way to overcome the problems that may arise when using mesophilic strains. This study reports the first thermophilic polyhydroxybutyrate-producing Cupriavidus species, which are known as the best polyhydroxybutyrate-producing microorganisms. Cupriavidus cauae PHS1 harbors a phbCABR cluster with high similarity to the corresponding proteins of C. necator H16 (80, 93, 96, and 97 %). This strain can produce polyhydroxybutyrate from a range of substrates, including acetate (5 g/L) and phenol (1 g/L), yielding 7.6 % and 18.9 % polyhydroxybutyrate, respectively. Moreover, the strain produced polyhydroxybutyrate at temperatures ranging from 25 to 50 degrees C, with the highest polyhydroxybutyrate content (47 degrees C) observed at 45 degrees C from gluconate. Additionally, the strain could incor-porate 3-hydroxyvalerate (12.5 mol. %) into the polyhydroxybutyrate polymer using levulinic acid as a pre-cursor. Thus, Cupriavidus cauae PHS1 may be a promising polyhydroxybutyrate producer as alternative for mesophilic polyhydroxybutyrate-producing Cupriavidus species
MSH2-MSH3 promotes DNA end resection during homologous recombination and blocks polymerase theta-mediated end-joining through interaction with SMARCAD1 and EXO1
No full textDNA double-strand break (DSB) repair via homologous recombination is initiated by end resection. The extent of DNA end resection determines the choice of the DSB repair pathway. Nucleases for end resection have been extensively studied. However, it is still unclear how the potential DNA structures generated by the initial short resection by MRE11-RAD50-NBS1 are recognized and recruit proteins, such as EXO1, to DSB sites to facilitate long-range resection. We found that the MSH2-MSH3 mismatch repair complex is recruited to DSB sites through interaction with the chromatin remodeling protein SMARCAD1. MSH2-MSH3 facilitates the recruitment of EXO1 for long-range resection and enhances its enzymatic activity. MSH2-MSH3 also inhibits access of POL theta, which promotes polymerase theta-mediated end-joining (TMEJ). Collectively, we present a direct role of MSH2-MSH3 in the initial stages of DSB repair by promoting end resection and influencing the DSB repair pathway by favoring homologous recombination over TMEJ
Zn2+ ion doping for structural modulation of lead-free Sn-based perovskite solar cells
No full textSn-based perovskites have intrinsic defects, such as Sn vacancies, oxidised components (Sn4+), and local lattice strain in the perovskite crystalline structure. In this study, Zn metal powder (Zn-0) was introduced to reduce Sn oxidation in the solution step based on the redox potential difference. Additionally, Zn2+ was introduced in the perovskite precursor, which decreased the intrinsic defects and lattice strain of the perovskite films. The diffusion length, particularly that of the hole, increased with a reduction in the lattice strain, and Zn doping led to interfacial energy-level alignment of the perovskite and hole-transporting layers. The reduced lattice strain decreased the defect density and charge carrier recombination of perovskite devices. The power conversion efficiency of the Zn-doped Sn-based perovskite solar cell was improved to 11.39% compared to the 8.56% of the reference device
Adopting Coding in Early Childhood Education: Teachers??? Perspectives
No full textThe recent push to introduce coding in early childhood education has been the subject of heated debate. A lack of theoretical and empirical research devoted to understanding coding education acceptance provided the motivation for this article. As a way to engage in the debate, this article investigated kindergarten teachers' acceptance of coding education by drawing on the theory of planned behavior framework, with self-efficacy, pedagogical beliefs, perceived ease of use, perceived usefulness, student readiness, teacher readiness, and parent readiness serving as external factors. The data were obtained from 236 in-service and preservice teachers in South Korea. Partial least square was employed to evaluate the research hypotheses. We find that self-efficacy and pedagogical beliefs exert a positive effect on perceived behavioral control. Perceived ease of use and perceived usefulness are pertinent for forming positive attitudes. Teacher readiness and parent readiness matter for generating positive subjective norm. Perceived behavioral control, attitude, and subjective norm all have a positive effect on behavioral intentions. The positive indirect effect of perceived usefulness on behavioral intentions through attitude is also noteworthy. In this article, we provide exploratory results as to how teachers believe and perceive coding in early childhood education. Practical insights are provided based on these initial findings