The Silk Road pattern (SRP) and circumglobal teleconnection pattern (CGT) are two well-known teleconnection patterns, representing the summer circulation variations of the Northern Hemisphere ...mid-latitudes, which have different definitions but are often regarded as one teleconnection pattern. In view of the distinct features of the SRP/CGT on the interannual (IA) and interdecadal (ID) timescales, the present study investigates the linkages and differences between the SRP and CGT on the two timescales, respectively. On the IA timescale, both the SRP and CGT feature a similar circumglobal wave train structure with strong and significant centers over Eurasia but show clear independence. Specifically, the SRP and CGT illustrate largely the mid-/high-latitude-related and tropics-related parts of the Northern Hemisphere upper tropospheric circulation variations, respectively. Also, the CGT shows a stronger connection to the Indian summer monsoon (ISM) heating and El Niño–Southern Oscillation than the SRP, which makes the CGT more like a tropical forcing-driven atmospheric mode and the SRP more like an internal atmospheric mode. The linkages and differences between them are associated with their asymmetrical relationship during their positive and negative phases, which are attributed mainly to the asymmetrical impact of the ISM heating/cooling on the Eurasian circulations. On the ID timescale, the SRP and CGT are characterized by a coherent two-wave train structure over Eurasia and feature a similar teleconnection pattern over Eurasia, which is associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation. The present findings on their linkages and differences are helpful in understanding the variability and prediction of the SRP and CGT.
In this paper, we investigate the Pontryagin trace anomaly for chiral fermions in a general curved background using Pauli-Villars regularization. We use both Feynman diagram method and Fujikawa's ...method to calculate the parity-odd contribution (Pontryagin term). Our result indicates that the trace anomaly of energy-momentum tensor for chiral fermions has Pontryagin term P=i1536π2ϵνσκλRρμνσRρμκλ which agrees with the work of Bonora et al. 1.
The ionospheric radio occultation measurements from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites during 2007–2012 are utilized to analyze variations of ...the hemispheric asymmetry in the equatorial ionization anomaly (EIA) in solstice seasons. A hemispheric asymmetry index (Ah) is introduced to quantitatively characterize the relative interhemispheric asymmetry or north‐south differences of the EIA crests. The seasonal, solar activity, and longitudinal dependences of the hemispheric asymmetry are investigated during these low to moderately high solar activity levels. Our main findings are as follows: (1) The transition of stronger crest from the winter to summer hemispheres generally took place during noon to afternoon hours (~11:00–14:00 LT), whereas the change of the EIA hemispheric asymmetry pattern toward a stronger summer crest actually started 2–3 h earlier. (2) Remarkable differences were observed in the EIA hemispheric asymmetry between June and December solstices. In June solstice, the transition from stronger winter to summer crests occurred later, and consequently, the duration with stronger winter crest lasted longer during the morning period. (3) In the afternoon hours, the magnitudes of relative interhemispheric asymmetry of EIA crests were obviously anticorrelated with the solar activity, while in the morning hours their solar activity dependence was weak. (4) Interhemispheric asymmetry of the crests and its transition time varied with longitudes. It is also found that the longitudinal and seasonal variations of the change rate of Ah was generally consistent with the corresponding variations of hemispheric asymmetry in ion production rate. Our results indicate that the photochemical process may also play a role in the EIA hemispheric asymmetry, in addition to the important contribution from the transequatorial neutral wind and equatorial fountain effects.
Key Points
Inflection point of the EIA hemispheric asymmetry index occurs in the morning
The EIA asymmetry depends on solar flux in the afternoon, but not in the morning
Pronounced seasonal and longitudinal variations of EIA asymmetry are found
The formate‐based rechargeable hydrogen battery (RHB) promises high reversible capacity to meet the need for safe, reliable, and sustainable H2 storage used in fuel cell applications. Described ...herein is an additive‐free RHB which is based on repetitive cycles operated between aqueous formate dehydrogenation (discharging) and bicarbonate hydrogenation (charging). Key to this truly efficient and durable H2 handling system is the use of highly strained Pd nanoparticles anchored on graphite oxide nanosheets as a robust and efficient solid catalyst, which can facilitate both the discharging and charging processes in a reversible and highly facile manner. Up to six repeated discharging/charging cycles can be performed without noticeable degradation in the storage capacity.
The formate/bicarbonate pair: A rechargeable hydrogen battery based on repetitive formate/bicarbonate interconversion in aqueous solution was developed. A hybrid material of Pd nanoparticles and reduced graphite oxide serves as the robust and efficient catalyst for both steps. Multiple charging and discharging cycles were performed with comparable storage/release efficiency and the resulting H2 gas is free of CO and CO2.
Recognition of a human's continuous emotional states in real time plays an important role in machine emotional intelligence and human-machine interaction. Existing real-time emotion recognition ...systems use stimuli with low ecological validity (e.g., picture, sound) to elicit emotions and to recognise only valence and arousal. To overcome these limitations, in this paper, we construct a standardised database of 16 emotional film clips that were selected from over one thousand film excerpts. Based on emotional categories that are induced by these film clips, we propose a real-time movie-induced emotion recognition system for identifying an individual's emotional states through the analysis of brain waves. Thirty participants took part in this study and watched 16 standardised film clips that characterise real-life emotional experiences and target seven discrete emotions and neutrality. Our system uses a 2-s window and a 50 percent overlap between two consecutive windows to segment the EEG signals. Emotional states, including not only the valence and arousal dimensions but also similar discrete emotions in the valence-arousal coordinate space, are predicted in each window. Our real-time system achieves an overall accuracy of 92.26 percent in recognising high-arousal and valenced emotions from neutrality and 86.63 percent in recognising positive from negative emotions. Moreover, our system classifies three positive emotions (joy, amusement, tenderness) with an average of 86.43 percent accuracy and four negative emotions (anger, disgust, fear, sadness) with an average of 65.09 percent accuracy. These results demonstrate the advantage over the existing state-of-the-art real-time emotion recognition systems from EEG signals in terms of classification accuracy and the ability to recognise similar discrete emotions that are close in the valence-arousal coordinate space.
With diminishing natural resources, there is an ever-increasing demand for cost-effective and sustainable production of fine and commodity chemicals. For this purpose, there is a need for new ...catalytic methods that can permit efficient and targeted conversion of fossil and biorenewable feedstocks with lower energy requirements and environmental impact. A significant number of industrial catalytic processes are performed by platinum-group-metal (PGM)-based heterogeneous catalysts capable of activating a range of important small molecules, such as CO, O2, H2, and N2. In contrast, there is a general feeling that gold (Au) cannot act as an efficient catalyst because of its inability to activate most molecules, which is essential to any catalytic processes. As a consequence, researchers have long neglected the potential for use of gold as a catalyst. In recent years, however, chemists have put forth tremendous effort and progress in the use of supported gold catalysts to facilitate a variety of useful synthetic transformations. The seminal discovery by Haruta in 1987 that suitably prepared Au-based catalysts were surprisingly active for CO oxidation even at 200 K initiated rapid development of the field. Since then, researchers have widely employed Au-based catalysts in many types of mild chemical processes, with special focus on selective reactions involving small molecules (for example, CO, H2O, O2, or H2) as a reactant. That gold in the form of tiny nanoparticles (NPs, generally less than 5 nm in diameter) can subtly activate the reactant molecules under mild conditions has been evoked to explain the superior effectiveness of gold compared with conventional PGMs. In this context, Au-based catalysts are gaining great significance in developing new green processes with improved selectivity and energy minimization. In this Account, we describe our efforts toward the development of a range of green and selective processes largely through the appropriate choice of Au catalysts coupled with the coactivation of a plethora of simple small molecules. We have focused on developing new mild and selective reductive transformations that can offer efficient alternatives to conventional Au-catalyzed hydrogenation processes. We have demonstrated Au-catalyzed selective transformation involving HCOOH activation, Au-catalyzed selective reduction involving CO and H2O activation, and Au-catalyzed C–N/C–C bond formation via alcohol activation with high selectivity. The interplay between the support and gold plays a critical role in the success of these transformations, thus highlighting the crucial importance of support in tuning the performance of supported Au NPs. Most of the reactions can tolerate a range of functional groups, and some can occur under ambient conditions. Depending on the specific process, we propose several mechanistic scenarios that describe the plausible small-molecule-mediated reaction pathways. Additionally, we have observed an unusual reactant-promoted H2O or H2 activation over supported Au NPs, thus offering new strategies for green and facile synthesis of diverse amides and heteroaromatic nitrogen compounds. We anticipate that key insights into how simple small molecules are activated for further reaction over Au NPs should lead to a better understanding of gold catalysis and the development of new innovative PGM-free technologies.
Synthetic community (SynCom) approaches can provide functional and mechanistic insights into how plants regulate their microbiomes, and how the microbiome in turn influences plant growth and health. ...Microbial cultivation and reconstruction play pivotal roles in this process, which enables researchers to reproducibly investigate the interactions between plants and a major proportion of plant-associated microbes in controlled laboratory conditions. Here, we summarize the emergence, current achievements, and future opportunities for using SynCom experiments in plant microbiome research, with a focus on plant root-associated bacteria.
Knowledge of awareness, behavior and barriers to putting carbon management in place is particularly useful for policy-makers in providing favorable conditions in support of firms’ climate change ...adaptation measures. According to unique data from in-depth interviews with firms from the most fossil fuel-intensive industries in Fujian, China, the present study indicated that the firms were relatively well informed of the knowledge and value of carbon management, and had a strong willingness to act. Nevertheless, there was no indication of actual behavior by these firms to enact carbon management, and a striking gap existed between awareness and behavior. The results also indicated the barriers, which were categorized into structural, regulatory, contextual and cultural. These barriers and their mutually reinforcing effects hampered the process of translating awareness into actual behavior.
► Firms were well informed of the knowledge and value of carbon management. ► Firms had a strong willingness to act carbon management. ► There was no indication of actual behavior by firms to enact carbon management. ► A striking gap existed between awareness and behavior. ► Structural, regulatory, contextual and cultural barriers hampered the process of translating awareness into behavior.
A robust automatic micro-expression recognition system would have broad applications in national safety, police interrogation, and clinical diagnosis. Developing such a system requires high quality ...databases with sufficient training samples which are currently not available. We reviewed the previously developed micro-expression databases and built an improved one (CASME II), with higher temporal resolution (200 fps) and spatial resolution (about 280×340 pixels on facial area). We elicited participants' facial expressions in a well-controlled laboratory environment and proper illumination (such as removing light flickering). Among nearly 3000 facial movements, 247 micro-expressions were selected for the database with action units (AUs) and emotions labeled. For baseline evaluation, LBP-TOP and SVM were employed respectively for feature extraction and classifier with the leave-one-subject-out cross-validation method. The best performance is 63.41% for 5-class classification.
Abstract
Transformation of greenhouse gas CO
2
and renewable H
2
into fuels and commodity chemicals is recognized as a promising route to store fluctuating renewable energy. Although several C
1
...chemicals, olefins, and gasoline have been successfully synthesized by CO
2
hydrogenation, selective conversion of CO
2
and H
2
into aromatics is still challenging due to the high unsaturation degree and complex structures of aromatics. Here we report a composite catalyst of ZnAlO
x
and H-ZSM-5 which yields high aromatics selectivity (73.9%) with extremely low CH
4
selectivity (0.4%) among the carbon products without CO. Methanol and dimethyl ether, which are synthesized by hydrogenation of formate species formed on ZnAlO
x
surface, are transmitted to H-ZSM-5 and subsequently converted into olefins and finally aromatics. Furthermore, 58.1%
p
-xylene in xylenes is achieved over the composite catalyst containing Si-H-ZSM-5. ZnAlO
x
&H-ZSM-5 suggests a promising application in manufacturing aromatics from CO
2
and H
2
.
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