We examine the extent to which institutional investors herd in the U.S. corporate bond market and the price impact of their herding behavior. We find that the level of institutional herding in ...corporate bonds is substantially higher than what is documented for equities, and that sell herding is much stronger and more persistent than buy herding. The price impact of herding is also highly asymmetric. While buy herding facilitates price discovery, sell herding causes transitory yet large price distortions. Such price destabilizing effect of sell herding is particularly pronounced for speculative-grade, small, and illiquid bonds, and during the financial crisis.
This work demonstrates that the use of high‐negative and high‐symmetry lacunary polyoxometalates (POMs) for the clustering of alkali metal ions is a feasible strategy not only for the formation of ...rare high‐nuclearity alkali‐metal clusters but also for the construction of new‐type all‐inorganic ionic porous materials. By the strategy, an unprecedented high‐nuclearity K‐H2O cluster {K42(H2O)60} with core–shell K6@K36 configuration is stabilized by 8 C3v‐symmetry trivacant POMs GeW9O3410−, forming a novel giant ionic alkali‐metal‐POM composite cluster {K42Ge8W72O272(H2O)60} with more than 100 metal centers. The incorporated 42‐nuclearity K‐H2O cluster {K42(H2O)60} exhibits the highest‐nuclearity alkali‐metal‐water cluster known to date in POM chemistry. Further, the giant {K42Ge8W72O272(H2O)60} clusters can be linked by another kind of alkali metal ions Na+ to generate a fascinating three‐dimensional all‐inorganic ionic porous framework with high chemical stability, proton conductivity, and water vapor adsorption.
Giant ionic cluster: The utilization of highly negative polyoxometalates for the clustering of alkali metal cations has allowed the synthesis of a rare all‐inorganic ionic porous material built from novel giant ionic clusters {K42Ge8W72O272(H2O)60} (K42W72), which exhibits high proton conductivity. The K42W72 not only is among the largest ionic clusters but also contains unprecedented core–shell K6@K36‐H2O cage.
Many luminescent stimuli responsive materials are based on fluorescence emission, while stimuli-responsive room temperature phosphorescent materials are less explored. Here, we show a kind of ...stimulus-responsive room temperature phosphorescence materials by the covalent linkage of phosphorescent chromophore of arylboronic acid and polymer matrix of poly(vinylalcohol). Attributed to the rigid environment offered from hydrogen bond and B-O covalent bond between arylboronic acid and poly(vinylalcohol), the yielded polymer film exhibits ultralong room temperature phosphorescence with lifetime of 2.43 s and phosphorescence quantum yield of 7.51%. Interestingly, the RTP property of this film is sensitive to the water and heat stimuli, because water could destroy the hydrogen bonds between adjacent poly(vinylalcohol) polymers, then changing the rigidity of this system. Furthermore, by introducing another two fluorescent dyes to this system, the color of afterglow with stimulus response effect could be adjusted from blue to green to orange through triplet-to-singlet Förster-resonance energy-transfer. Finally, due to the water/heat-sensitive, multicolor and completely aqueous processable feature for these three afterglow hybrids, they are successfully applied in multifunctional ink for anti-counterfeit, screen printing and fingerprint record.
Multicultural integration brings opportunities and challenges to the field of education, and the innovation of Civics education in higher vocational colleges and universities becomes increasingly ...essential. In this paper, the reinforcement learning algorithm is used to construct a Civics teaching mode with precise teaching intervention, which quantifies students’ learning ability and learning status by combining the Civics learning ability level parameter. The difficulty coefficient of Civics exercises determines the students’ mastery of Civics content. Based on the students’ Civics learning ability and learning status, a precise teaching intervention strategy was formulated, and the teaching intervention was used in practice to explore the effectiveness of the accurate intervention Civics teaching model in terms of the change of students’ ability and performance. The results show that under the Precision Intervention Civics Teaching Model, students with low collaborative learning and high problem-solving ability changed from unidirectional PR→RS to bidirectional PA↔PR, indicating that the Precision Intervention Teaching Model can improve students’ learning ability. The passing rate of students under this model were maintained at 70%, the average score was above 70, and the students’ performance in Civics was significantly improved compared with the traditional teaching model.
In the multimedia context, it is important to enrich the teaching forms, challenge the traditional teaching concepts and realize the innovation of education mode. In this paper, a detailed review of ...translation strategies for college students in the multimedia context is presented, and the traditional GLR translation teaching analysis algorithm is analyzed. To compensate for the shortcomings of low translation teaching efficiency caused by over-fitting in the traditional GLR translation teaching analysis algorithm, a Bayesian model is constructed, and an adversarial neural network is built on its basis. Generate a translation teaching innovation model applicable to the translation teaching of university students. The translation teaching method is evaluated using the BLEU evaluation method. Experimental results: Both the correct translation rate of utterances based on the statistical computing method and dynamic memory algorithm reached 90%-95%. The traditional GLR translation teaching analysis algorithm achieved 95% correctness in recognizing declarative sentences, while the correctness rate for question and exclamation sentences was less than 95%. The correct translation rate of all the statements of the innovative model of translation teaching reached more than 97%. It can be seen that: The innovative model of translation teaching for college students with multimedia backgrounds is simpler and faster in calculation and more practical than other translation teaching algorithms, which is suitable for English translation work of college students and meets the proofreading needs of college students for translation teaching.
This study investigates strategies based on natural language processing to improve the efficiency and effectiveness of English reading comprehension by analyzing and optimizing reading comprehension ...models. We introduce the main framework of the English reading comprehension task, including the word embedding representation layer, the context encoding layer, the information interaction layer, and the output layer. The article utilizes the Word2vec model and decision tree ID3 algorithm to enhance the efficiency and accuracy of reading comprehension. The research data comprised 800 English articles, with 60% used for training and 40% used for testing. The articles were graded for difficulty and resources were pushed. It was found that the model proposed in this study performs better in difficulty grading (with a rating range of 0.797-0.926) and is more efficient in terms of time overhead (feature extraction time of about 10 milliseconds, and grading time of 1.7-2.6 seconds), compared to the traditional models such as BiLSTM and RNN. The pushed resources significantly correlate with learners’ self-assessed difficulty and actual performance. The NLP-based strategy proposed in the paper shows significant advantages in both efficiency and accuracy, and helps to improve English learners’ reading comprehension.
As information technology increasingly develops, cloud computing has become an emerging computer network technology, which brings great convenience to network life. In order to ensure network ...security while fully enjoying this convenience, this paper established the laboratory cloud platform and network topology using the single node deployment mode of Openstack, obtained the software system architecture by applying B/S three-tier architecture model for laboratory development, and finally constructed cloud computing system of the laboratory by integrating encryption technology, digital signature technology, fingerprint recognition technology and dynamic password technology. After functionality, security and performance tests of the laboratory cloud platform, the application effect indicates that, some functional modules of the platform are in line with the desired results, the operation success rate is up to 100%, a 64G server can assume the operation of about 22 virtual machines, the number of server receiving and processing reaches 33 per second, and the throughput climbs up to 980,000 bytes per second. Therefore, it is concluded that with the support of cloud computing, the laboratory basically meets the desired use demand, which can effectively intercept unauthorized operation instructions, and get good carrying capacity and load capacity while strengthening network security.
A simple, bioinspired approach to effectively prevent the restacking of chemically converted graphene sheets in multilayered films is presented. The method enables the creation of a new generation of ...supercapacitors that combine high energy density, high power density, and high operation rates.
This study demonstrates a novel strategy for colorimetric/fluorescent/surface enhanced Raman scattering (SERS) triple-mode sensing of nitrite based on Griess reaction modulated gold nanorods ...(GNRs)-Azo-gold nanoparticles (GNPs) (GNRs-Azo-GNPs) assembly. The p-aminothiophenol (PATP)-capped GNRs (GNRs@PATP) and 1,8-diaminonaphthalene (DAP)-modified GNPs (GNPs@DAP) are first synthesized through Au–S and Au–N bonds, respectively. Upon being excited at 365nm, the dispersion of GNRs-GNPs (GNRs@PATP and GNPs@DAP) emits cyan fluorescence. Next, the addition of nitrite into the GNRs-GNPs induces the formation of GNRs-Azo-GNPs assembly, resulting in the enhancement of color and decrease of fluorescence. Therefore, the GNRs-Azo-GNPs assembly can not only be used as a naked-eye indicator of nitrite changed from orange-yellow to purple, but also as a highly selective ‘‘fluorescence quenching’’ probe due to the fluorescence resonance energy transfer (FRET) between azo-moiety and DAP. The limit of detection (LOD) for nitrite is 0.05μM by colorimetry and 0.01μM by fluorescence. Meanwhile, the GNRs-Azo-GNPs assembly possesses controllable core–satellites nanostructures and enables on-field SERS detection of nitrite with the LOD of 0.8nM. More importantly, the GNRs-GNPs sensing system can not only be used as a paper-based test strip for on-site fast screening of nitrite with a high sensitivity and selectivity, but also as a SERS substrate for reliable quantitative analysis of nitrite. This study offers a new method for on-site visual detection of nitrite in human urine and meat products, as well as provides a strategy for designing multi-mode sensing platform for various applications.
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•The GNRs-GNPs enables the colorimetric and fluorescent sensing of NO2−.•A paper strip containing GNRs-GNPs can be used for on-site fast screening of NO2−.•The GNRs-GNPs can be used as SERS substrates for quantitative analysis of NO2−.
Summary
Thermosensitive genic male sterility (TGMS) lines serve as the major genetic resource for two‐line hybrid breeding in rice. However, their unstable sterility under occasional low temperatures ...in summer highly limits their application. In this study, we identified a novel rice TGMS line, ostms18, of cultivar ZH11 (Oryza sativa ssp. japonica). ostms18 sterility is more stable in summer than the TGMS line carrying the widely used locus tms5 in the ZH11 genetic background, suggesting its potential application for rice breeding. The ostms18 TGMS trait is caused by the point mutation from Gly to Ser in a glucose‐methanol‐choline (GMC) oxidoreductase; knockout of the oxidoreductase was previously reported to cause complete male sterility. Cellular analysis revealed the pollen wall of ostms18 to be defective, leading to aborted pollen under high temperature. Further analysis showed that the tapetal transcription factor OsMS188 directly regulates OsTMS18 for pollen wall formation. Under low temperature, the flawed pollen wall in ostms18 is sufficient to protect its microspore, allowing for development of functional pollen and restoring fertility. We identified the orthologous gene in Arabidopsis. Although mutants for the gene were fertile under normal conditions (24°C), fertility was significantly reduced under high temperature (28°C), exhibiting a TGMS trait. A cellular mechanism integrated with genetic mutations and different plant species for fertility restoration of TGMS lines is proposed.
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