This review aims at investigating the related studies on the role of teacher burnout and teacher apprehension in learners' academic achievement. The negative effect of teacher burnout on learners' ...academic achievement has been corroborated in the review of the literature. Furthermore, the effect of teacher apprehension on learners' academic success has not been widely studied. However, some stressors such as having insufficient L2 knowledge, cultural differences, and classroom management problems can affect learners' academic achievements. Finally, the pedagogical implications are illuminated for teachers, administrators, researchers, managers, teacher trainers, and counselors to decrease teacher burnout and apprehension and to develop language teaching quality in the language educational system. Some suggestions for further research are also provided to expand the current literature on teacher burnout and apprehension in English as a Foreign Language (EFL) contexts.
Amorphous MoS2 nanoflowers assembled by lamellar nanosheets have been successfully synthesized by a facile hydrothermal method. They were characterized by X-ray diffraction (XRD), Raman spectroscopy, ...scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and evaluated as electrochemical catalysts in the hydrogen evolution reaction (HER). Moreover, the effect of preparation temperature was also discussed. It was found that these catalysts exhibited excellent HER activity compared to commercial bulk MoS2 microparticles due to the special structure of nanoflowers assembled by nanosheets with few layers, exposing much more active sites and reducing intrinsic resistance. And the catalyst obtained at 220 °C showed the best activity with the largest exchange current density and the smallest Tafel slope of 52 mV dec−1, which made it a promising HER electrocatalyst for practical applications.
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•Amorphous MoS2 nanoflowers have been successfully prepared by a hydrothermal method.•Amorphous MoS2 nanoflowers exhibit excellent activity and stability in the HER.•A relatively low Tafel slope of 52 mV dec−1 was obtained.•A small onset potential of −130 mV was also observed.
Microplastics are widely distributed, such as oceans, rivers and the atmosphere, with many opportunities for human exposure and potential health risks. Polystyrene microplastic (PS-MPS) exposure has ...been found to cause sperm damage to mice; however, the mechanism by which this happens remains unclear. Here, GC-2 cells, a mouse spermatocyte line, were exposed to 5 µm PS-MPS to investigate mitochondrial damage. The results showed that 5 µm PS-MPS decreased ATP content, reduced the mitochondrial membrane potential, damaged the integrity of the mitochondrial genome, and caused an imbalance of homoeostasis between mitochondrial division and fusion. The mitochondrial PINK1/Parkin autophagy pathway was activated. Time-series analysis revealed that PS-MPS damaged the mitochondrial structure through cellular oxidative stress, and mitochondrial function was maintained to some extent after PS-MPS damage. This study revealed the mitochondrial toxicity of polystyrene microplastics, thus providing a basis for understanding the causes of sperm damage by polystyrene microplastics.
•Polystyrene microplastics induce mitochondrial damage to GC-2 cell structure and function.•PINK1/Parkin pathway is involved in mitochondrial autophagy induced by polystyrene microplastics.•Oxidative damage to cells is a possible cause of mitochondrial damage by polystyrene microplastic exposure.
Activated sludge (AS), which has been in use for 100 years, has been the most popular biological process in various wastewater treatment plants (WWTPs), in which bacteria plays central roles in ...pollutant removal. However, the potential relationship between bacteria taxa and the niches occupied by specific functional bacteria in AS are largely unknown. Here, correlation‐based network analysis was applied to a 16S rRNA gene pyrosequencing dataset containing > 760 000 sequences of 50 AS samples from globally distributed full‐scale WWTPs. The results showed that (i) bacterial assembly in AS was nonrandomly arranged by taxonomic relatedness and (ii) intra‐ and inter‐phylum/class co‐occurrence higher than expected by chance was induced by multiple deterministic processes, such as habitat filtering and competition. Moreover, based on bacterial occupancy, a prevalent core set of cosmopolitan functional bacteria (e.g. multiple nitrogen‐cycling‐related bacteria) was widely distributed in the AS of different WWTPs, showing strong ecological associations among them. Additionally, the AS network has statistical and structural characteristics similar to those of previously reported ecological networks, such as power‐law connectivity distribution and nonrandomly connected properties. Overall, this work provides novel insights into the bacterial associations within AS and sheds light on the ecological rules guiding bacterial assembly in WWTPs.
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•Starting from the energy grade, 12 typical industries are divided into three categories.•Evaluate the application potential of waste heat recovery technology in industry.•Compare the ...difference between advanced and traditional technology, highlight its contribution.•The future research directions with great potential are put forward.
Serious energy crises and ecological pollution have had negative impacts on all countries worldwide. These challenges are largely attributed to the production and operation of industries. Nevertheless, the advent of advanced waste heat recovery approaches has given rise to unprecedented opportunities and challenges in the current grave energy and environmental situation. The recovery and utilisation of waste-heat in various industries is an effective approach to improving economic benefits, conserving energy, and reducing emissions. In this review, 12 typical industries are preliminarily classified into three categories, according to the waste-energy grade. From the perspective of typical waste-heat sources, the waste heat recovery potentials of various technologies are analysed and discussed in terms of thermal performance, economic benefits, and environmental benefits. Subsequently, the development of a waste heat recovery approach is comprehensively reviewed, and the performance and structural configuration are summarised and scientifically compared. A detailed technical report is presented on the effective responses to pollutant emissions in various industries. Finally, the limitations in the current research and potential future directions are discussed. Through a comprehensive review of the recovery and utilisation of waste-heat in complex or large industries, this study provides constructive guidelines for researchers and enterprises engaged in related fields. Concurrently, its fills knowledge gaps by providing comprehensive information and the latest research results on the recovery and utilisation of waste-heat in various industries.
We theoretically investigated a hybrid absorptive–dispersive optical multistability (OM) behavior in a three-level ladder-type quantum well system inside a unidirectional ring cavity. We find that ...the frequency detuning of the control field and the electronic cooperation parameter as well as the total decay rates can affect the optical multistability behavior dramatically, which can be used to manipulate efficiently the threshold intensity and the hysteresis loop. The effect of the intensity of the control field on the OM is also studied. Our study is much more practical than its atomic counterpart due to its flexible design and the wide adjustable parameters. Thus it may provide some new possibilities for technological applications in optoelectronics and solid-state quantum information science.
Soil salinity is one of several major abiotic stresses that constrain maize productivity worldwide. An improved understanding of salt-tolerance mechanisms will thus enhance the breeding of ...salt-tolerant maize and boost productivity. Previous studies have indicated that the maintenance of leaf Na+ concentration is essential for maize salt tolerance, and the difference in leaf Na+ exclusion has previously been associated with variation in salt tolerance between maize varieties.
Here, we report the identification and functional characterization of a maize salt-tolerance quantitative trait locus (QTL), Zea mays Na
+
Content1 (ZmNC1), which encodes an HKT-type transporter (designated as ZmHKT1).
We show that a natural ZmHKT1 loss-of-function allele containing a retrotransposon insertion confers increased accumulation of Na+ in leaves, and salt hypersensitivity. We next show that ZmHKT1 encodes a plasma membrane-localized Na+-selective transporter, and is preferentially expressed in root stele (including the parenchyma cells surrounding the xylem vessels). We also show that loss of ZmHKT1 function increases xylem sap Na+ concentration and causes increased root-to-shoot Na+ delivery, indicating that ZmHKT1 promotes leaf Na+ exclusion and salt tolerance by withdrawing Na+ from the xylem sap.
We conclude that ZmHKT1 is a major salt-tolerance QTL and identifies an important new gene target in breeding for improved maize salt tolerance.
With the data from the Web of Science Core Collection-Citation database for the period (1970–2020), we conducted a dynamic visual systematic review of the literature on academic publishing with the ...help of bibliometric software, CiteSpace, and VOSviewer. The main purpose is to reveal the internal structures and hidden inferences, including the diversified discipline, top-ranked journals, most widely occurring topics, most cited and leading articles, highly productive and outstanding scholars, and most contributing institutions and countries. The co-citation, co-occurrence, cluster detection, and strong citation burstness were employed to show the intellectual base, evolutionary stages, and dynamics of transitions of academic publishing. The study defines the whole profile of international academic publishing, presenting its diachronic evolution, identifying research front, detecting emerging trends and abrupt changes. It expands the previous paradigm that ignored the large data corpus, aiming to provide certain reference value for future research of academic publishing.
A fully-integrated 77 GHz frequency doubling two-path phased-array frequency-modulated continuous-wave (FMCW) transceiver for automotive radar applications is proposed. By utilizing the frequency ...doubling scheme, the chirp bandwidth is improved, and the complexity of the frequency synthesizer and the insertion loss of the local-oscillating (LO) distribution network are both reduced. Top-injected coupled resonator based wide locking range technique is proposed in the frequency doublers to minimize the required injection power to cover the chirp bandwidth plus enough PVT variation margin, and therefore reduce the power consumption of the LO distribution network. Current-reused coupled resonator technique is utilized to implement the LO phase shifting in each receiving path. The digitally controlled artificial dielectric-based transmission lines are inserted in the low noise amplifiers to provide the operation frequency calibration capability. The receiving two-path signals are converted into intermediate frequency by low flicker noise current-mode passive mixers and then combined in the trans-impedance amplifier, followed by the reconfigurable analog baseband processing. Fabricated in 65 nm CMOS, the FMCW transceiver has achieved 1.93 GHz maximum chirp bandwidth, 12.9 ~ 13.2 dBm maximum transmitting power, and 47.8 ~ 100.7 dB programmable receiving conversion gain. The transceiver consumes 343 mW power and 4.64 mm 2 chip area including all of the pads.
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