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The collaborative learning approach as a universal teaching strategy is widely used in online learning. It is proven that the group leader has an important impact on group collaborative knowledge construction in online collaborative learning (OCL). However, limited research is available on how leadership styles influence a group. Universal teaching strategy is widely used in online learning. This study, the authors adopted lag sequential analysis, epistemic network analysis, and social network analysis to explore the influence of divergent and convergent leadership styles on cognitive engagement in OCL groups. Compared with convergent leadership, divergent leadership strengthened online collaborative cognitive engagement through significant organizer and manager roles, triggered high-quality cognitive behavior transformation within the group, and promoted the balanced development of learners' cognitive structure.

The underlying mechanisms between family income and mental health of children merit further investigation. Based on the family stress model and the psychological factors model, we proposed that familial factors (parental depression and parenting) and the individual factor (child self-esteem) would mediate the relationship between family income and child depression concurrently. Data were obtained from a nationally representative longitudinal survey (i.e., the China Family Panel Studies), involving 1,283 families (2,732 parents and 1,384 children). The age of the children ranged from 4 to 15 years (M[subscript age] = 8.04, SD = 1.87) at baseline. Path analysis showed that the effect of family income (in 2010, T1) on child depression (in 2014, T3) was mediated by parental depression (in 2012, T2), parental bonding (in 2012 or 2014, T2 or T3), and child self-esteem (in 2012 or 2014, T2 or T3), in a parallel rather than sequential manner. The findings indicate that health policies and psychosocial interventions that simultaneously improve parental depression, parenting techniques, and child self-esteem would be an effective approach to alleviate the impact of family income on child depression.

Introduction: The contamination of Trichoderma species causing green mold in substrates poses a significant obstacle to the global production of Lentinula edodes, adversely impacting both yield and quality of fruiting bodies. However, the diversity of Trichoderma species in the contaminated substrates of L. edodes (CSL) in China is not clear. The purpose of this study was to assess the biodiversity of Trichoderma species in CSL, and their interactions with L. edodes. Methods: A comprehensive two-year investigation of the biodiversity of Trichoderma species in CSL was conducted with 150 samples collected from four provinces of China. Trichoderma strains were isolated and identified based on integrated studies of phenotypic and molecular data. Resistance of L. edodes to the dominant Trichoderma species was evaluated in dual culture in vitro. Results: A total of 90 isolates were obtained and identified as 14 different Trichoderma species, including six new species named as Trichoderma caespitosus, T. macrochlamydospora, T. notatum, T. pingquanense, T. subvermifimicola, and T. tongzhouense, among which, T. atroviride, T. macrochlamydospora and T. subvermifimicola were identified as dominant species in the CSL. Meanwhile, three known species, namely, T. auriculariae, T. paraviridescens and T. subviride were isolated from CSL for the first time in the world, and T. paratroviride was firstly reported to be associated with L. edodes in China. Notebly, the in vitro evaluation of L. edodes resistance to dominant Trichoderma species showed strains of L. edodes generally possess poor resistance to Trichoderma contamination with L. edodes strain SX8 relatively higher resistant. Discussion: This study systematically investigated the diversity of Trichoderma species in the contaminated substrate of L. edodes, and a total of 31 species so far have been reported, indicating that green mold contaminated substrates of edible fungi were undoubtedly a biodiversity hotspot of Trichoderma species. Results in this study will provide deeper insight into the genus Trichoderma and lay a strong foundation for scientific management of the Trichoderma contamination in L. edodes cultivation. [ABSTRACT FROM AUTHOR]

In view of the high failure rate of key parts and low reliability of the whole machine in the working process of the new forage crusher, the expert scoring method was used to predict the reliability of the forage crusher, and the IFM was used to allocate the reliability. The results showed that the predicted reliability value of forage grass crushing machine was 0.668, which could not meet the requirements of reliability standard of forage grass crushing machine in China. Reliability was redistributed based on the prediction results, and lower failure rate weights and higher reliability were assigned to rotor and power transmission parts. High failure rate weight and low reliability were assigned to the crusher body. After redistributing the reliability of each subsystem, the reliability of the whole machine was 0.902 59, which met the reliability requirements of forage kneading machine system. The study indicates that the research can provide a method of reference for reliability prediction and distribution of forage processing machinery. [ABSTRACT FROM AUTHOR]

Background: This study is to evaluate and compare the improvement of upper airway morphology and hyoid bone position in children with Class II mandibular retrusion treated with Invisalign mandibular advancement (MA) and Twin-Block (TB) appliances, utilizing cone beam computed tomography (CBCT). Methods: 32 children aged between 8 and 11.5 years old were included in this study, with an average age of 10.2 years old. These children were divided into two groups, MA and TB, with 16 children in each group. Changes in upper airway morphology and hyoid bone position before and after treatment were analyzed using CBCT. Results: (1) Changes in upper airway before and after treatment: the oropharynx volume (Or-V), the oropharynx minimum cross-sectional area (Or-mCSA), the hypopharynx volume (Hy-V), and the hypopharynx minimum cross-sectional area (Hy-mCSA) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05) compared to pre-treatment status. (2) Changes in hyoid bone position before and after treatment: The distances between H point and third cervical vertebra (H-C3), H point and pogonion (H-RGN), H point and mandibular plane (H-MP), H point and Frankfort horizontal plane (H-FH), H and S point (H-S), and H point and palatal plane (H-PP) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05). Conclusion: Both MA and TB appliances effectively improved the structural narrowness of the upper airway and reduced respiratory resistance, thus improving breath quality. However, MA showed more effectiveness in improving the narrowest part of the hypopharynx compared to TB. Both appliances also promoted anterior downward movement of the hyoid bone, which opens the upper airway of the oropharynx and hypopharynx and helps the upper airway morphology return to normal range. [ABSTRACT FROM AUTHOR]

Bioelectrochemical systems (BESs) are promising technologies for energy and product recovery coupled with wastewater treatment, and the core microbial community in electrochemically active biofilm in BESs remains controversy. In the present study, 7 anodic communities from 6 bioelectrochemical systems in 4 labs in southeast, north and south-central of China are explored by 454 pyrosequencing. A total of 251,225 effective sequences are obtained for 7 electrochemically active biofilm samples at 3% cutoff level. While Alpha-, Beta-, and Gamma-proteobacteria are the most abundant classes (averaging 16.0-17.7%), Bacteroidia and Clostridia are the two sub-dominant and commonly shared classes. Six commonly shared genera i.e., Azospira, Azospirillum, Acinetobacter, Bacteroides, Geobacter, Pseudomonas, and Rhodopseudomonas dominate the electrochemically active communities and are defined as core genera. A total of 25 OTUs with average relative abundance >0.5% were selected and designated as core OTUs, and some species relating to these OTUs have been reported electrochemically active. Furthermore, cyclic voltammetry and chronoamperometry tests show that two strains from Acinetobacter guillouiae and Stappia indica, bacteria relate to two core OTUs, are electrochemically active. Using randomly selected bioelectrochemical systems, the study has presented extremely diverse bacterial communities in anodic biofilms, though, we still can suggest some potentially microbes for investigating the electrochemical mechanisms in bioelectrochemical systems. [ABSTRACT FROM AUTHOR]

A surge in the number of international arrivals awaiting coronavirus disease 2019 (COVID-19) screening overwhelmed healthcare workers and depleted medical resources in designated hospitals in Beijing, China in March 2020. The People's Government of Beijing Municipality therefore issued a policy which required the mandatory transfer of all asymptomatic passengers arriving from a foreign country to designated quarantine hotels, and the transfer of passengers with fever or respiratory symptoms to designated hospitals. Xiaotangshan Designated Hospital, a severe acute respiratory syndrome hospital in 2003, was rapidly renovated and put into operation with the main tasks of screening and isolating symptomatic international arrivals at Beijing Capital International Airport, providing basic medical care for mild to moderate COVID-19-positive cases, and rapidly referring severe to critical COVID-19-positive cases to higher-level hospitals. During the month-long period of its operation, 2171 passengers were screened and 53 were confirmed as having COVID-19 (six severe to critical). We describe how the use of Xiaotangshan Designated Hospital in this way enabled the efficient grouping and assessment of passengers arriving from a foreign country, the provision of optimal patient care without compromising public safety and the prioritization of critically ill patients requiring life-saving treatment. The designated hospital is a successful example of the World Health Organization's recommendation to renovate existing medical infrastructures to improve the COVID-19 response capacity. The flexible design of Xiaotangshan Designated Hospital means that it can be repurposed and reopened at any time to respond to the changing pandemic conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Luobushan deposit is controlled by both structure and lithology. • The sulfides have micro- to fine-grained textures. • The reduction of marine sulfate has undergone a shift from BSR to TSR. • The main source of metal is the lower Permian bioclastic limestone. • The Luobushan deposit is similar to MVT deposits. The Luoboshan Pb-Zn deposit (0.2 Mt Pb + Zn metal reserves, @ 0.94 % Pb and 5.33 % Zn) is located in the Lanping-Simao Basin in the southern part of the Sanjiang Tethys metallogenic domain in Yunnan Province, SW China. The deposit comprises three ore bodies hosted in the lower Permian bioclastic and micritic limestone. Ore body I is stratiform (mineralization is small in scale and ores have been mined out), with average grades of 0.02–1.44 % Pb and 1.5–14.88 % Zn. Ore bodies II and III are lens-like, the average grades of them are 0.10–5.07 % Pb and 1.68–12.39 % Zn, and 0.10–1.71 % Pb and 1.14–11.79 % Zn, respectively. Two hydrothermal stages were identified in the Luoboshan deposit: Pyrite-I-sphalerite-galena-calcite (stage I) and Pyrite-II-calcite (stage II). The in-situ δ34S values of pyrite and sphalerite reveals a medium range of −8.80 ‰ to +10.1 ‰. Furthermore, Py-I and sphalerite exhibit low δ34S values from −8.80 ‰ to −3.04 ‰, but Py-II displays high δ34S values (+2.37 ‰ to +10.0 ‰). These results suggest distinct formation mechanism for reduced sulfur during different stages of Pb-Zn mineralization. A reasonable explanation is that a transition from bacterial sulfate reduction (BSR) in the early stage to thermochemical sulfate reduction (TSR) in the late stage as the likely mechanism for the formation of reduced sulfur. In addition, the in-situ Pb isotopes exhibit a narrow range (206Pb/204Pb = 18.660–18.672, 207Pb/204Pb = 15.665–15.677 and 208Pb/204Pb = 38.940–38.980), indicating that the metals originated from either a single source or a uniform mixture of different sources. Comparison of geological charateristics and isotopic geochemical data (S and Pb) indicates that the basin sedimentary strata (wall rocks) is the only and most probable source. Hence, we propose that the formation of the Luoboshan deposit involved biogenic in-situ acid generation of marine sulfates, which subsequently mixed with Pb-and-Zn-rich hydrothermal fluids, initiating TSR and resulting in Pb-Zn mineralization. [ABSTRACT FROM AUTHOR]

Although carbonate rocks are important for carbonate-hosted Pb Zn deposits, there is no effective constraint on the role of carbonate rocks during the Pb Zn mineralization process. This paper uses the giant Huize Pb Zn deposit (>7 Mt. metals @ 25–35 % Pb + Zn) as a case study and employs zinc isotopes to gain new insights into such issue. The Huize deposit, located in the Sichuan-Yunnan-Guizhou (SYG) Pb Zn metallogenic province, is the largest carbonate-hosted deposit in the western Yangtze Block, SW China. Zinc isotope compositions of sphalerite, altered carbonate rocks and fresh carbonate rocks from the Huize deposit are of +0.39 ‰ to +0.68 ‰ (mean + 0.52 ‰, n = 20), −0.25 ‰ to +0.34 ‰ (mean + 0.07 ‰, n = 11) and + 0.35 ‰ to +0.71 ‰ (mean + 0.51 ‰, n = 6), respectively. The initial δ66Zn value of hydrothermal fluids calculated by the Rayleigh fractionation simulation is +0.4 ‰. Such zinc isotope signatures are significantly different from those of potential source rocks, such as the basement Proterozoic metamorphic rocks (δ66Zn = +0.10 ‰ to +0.34 ‰, mean + 0.22 ‰), the host Upper Ediacaran to Middle Permian sedimentary rocks (δ66Zn = −0.24 ‰ to +0.35 ‰, mean + 0.1 ‰) and the cover Upper Permian Emeishan basalts (δ66Zn = +0.30 ‰ to +0.44 ‰, mean + 0.35 ‰). Hence, it is likely that the carbonate rocks acted zinc source and provided heavy zinc isotopes for the Pb Zn mineralization. The ore-forming fluids extracted the heavy zinc isotopes of the ore-hosting carbonate rocks, resulting in the zinc isotopes of the altered carbonate rocks being far lighter than those of the marine carbonate rocks (δ66Zn = +0.24 ‰ to +1.32 ‰). The sulfur isotope compositions (+12.9 ‰ to +15.6 ‰, mean + 14.3 ‰, n = 20) of sphalerite from the Huize deposit also suggested that the source of reduced sulfur is the marine sulfate minerals within the ore-hosting carbonate rocks. Therefore, carbonate rocks play key roles in the formation of carbonate-hosted Pb Zn deposits: 1) provide ore-forming elements and ore-hosting space through dissolution; 2) cause isotope variation (e.g., zinc isotopes) by isotope exchange; 3) act as a carbonate buffer to adjust physicochemical conditions (e.g., pH) via cyclical carbonate dissolution, CO 2 degassing and recrystallization. On the other hand, the zinc isotope mapping shows that the western part of the SYG Pb Zn metallogenic province has lighter zinc isotopes than those of the eastern part. This suggests that the migration pathway of hydrothermal fluids is likely west to east, which provides a new clue for regional Pb Zn ore prospecting. The outcomes have important benefits for understanding the genesis of Pb Zn deposits, the role of carbonate rocks and the application of zinc isotopes. [Display omitted] • Zinc isotope fractionation was jointly controlled by fluid mixing and Rayleigh fractionation. • Heavy zinc isotopes were extracted from carbonate rocks through water/rock interaction. • Carbonate rocks played a key role in the formation of carbonate-hosted Pb Zn deposits. • Zinc isotope mapping provides a new clue for regional Pb Zn ore prospecting. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Dingtoushan carbonate-hosted epigenetic hydrothermal deposit is a Se-rich Pb-Zn deposit. • Fluid mixing is the main sulfide precipitation mechanism in the Dingtoushan Se-rich Pb-Zn deposit. • Selenium enrichment in sphalerite is jointly controlled by Se-rich fluid mixing and temperature. Selenium (Se) is a typical dispersed element (crust Clarke value only 0.05 × 10-6) and is mainly enriched in black shales (>20 × 10-6). Selenium can also be associated with Pb-Zn and U deposits. In carbonate-hosted epigenetic hydrothermal Pb-Zn deposits, the selenium contents in sulfides are commonly < 50 × 10-6, and the selenium is mainly enriched in galena, whereas the selenium contents in sphalerite are often < 10 × 10-6. There are few studies on Se-rich carbonate-hosted epigenetic hydrothermal Pb-Zn deposits, and the origin of such deposits needs more in-depth exploration. In this study, we selected the Dingtoushan Se-rich Pb-Zn deposit in the western Yangtze Block, SW China, and utilized in-situ trace elements and S-Pb isotopes of Se-rich sphalerite to investigate this issue. There are two textures of sphalerite formed in the Dingtoushan deposit, of which subhedral sphalerite (Sp-I) precipitated during the early stage, whereas euhedral sphalerite (Sp-II) generated during the late stage. The results of trace elements show that the Dingtoushan deposit is significantly enriched in selenium (>22 × 10-6) compared with other carbonate-hosted Pb-Zn deposits (<22 × 10-6, generally < 10 × 10-6) in the Sichuan-Yunnan-Guizhou (SYG) Pb-Zn metallogenic province. In detail, a positive correlation between Se, Cd, In and Cu contents and sulfur isotopes of sphalerite is identified at the deposit scale, but no relationship is observed at the grain scale. In addition, the late stage Sp-II with δ34S values of −7‰ to −3‰ is rich in selenium and other trace elements, whereas the early stage Sp-I with isotopically light sulfur (δ34S = -29 ‰ to −8‰) is depleted of them. This indicates that in the early stage, insufficient addition of hydrothermal fluid resulted in relatively low temperature, and sulfur formed by bacterial sulfate reduction (BSR) was mainly involved in mineralization. With the addition of a large amount of hydrothermal fluid, thermochemical sulfate reduction (TSR) was induced, which leads to the formation of sphalerite in the late stage with relatively high δ34S values. Furthermore, the Pb isotopes reveal that the ore-forming metals were likely derived from the Cambrian black shales. Hence, we infer that fluid mixing is the main sulfide precipitation mechanism and may cause the positive correlation of selenium concentrations and δ34S values. On the other hand, at the grain scale of sphalerite, the variation of selenium contents shows a negative correlation with temperature, suggesting that temperature may play a critical role in selenium enrichment in sphalerite. This study highlights that selenium enrichment in sphalerite is jointly controlled by fluid mixing and temperature. The degree of fluid mixing dominated the selenium concentration in hydrothermal fluid, but high temperature may not be conducive to selenium incorporation into sphalerite. Our new results indicate that sphalerite in the carbonate-hosted epigenetic hydrothermal deposits is also a major host for selenium and such type deposits may have a great economic potential for selenium resource. [ABSTRACT FROM AUTHOR]

Abstract: Effects of FeCl3 on anaerobic digestion of cyanobacterial biomass from Lake Chao, one of the most serious eutrophic freshwater lakes in China, were investigated. Results showed that FeCl3 was one feasible additive for the anaerobic process and methane generation rate and yield were both enhanced. The maximum methane yield reached 234mLg−1 based on the degraded volatile solid when the dosed FeCl3 was 0.25gL−1, while the methane yield was only 131mLg−1 in the control reactor. Decomposition efficiency of cyanobacterial biomass and release of element P were promoted significantly (P <0.05). [Copyright &y& Elsevier]

Sediment microorganisms are the main drivers of the material circulation and organic matter degradation processes in rural black and odorous water bodies(RBOWB), and the community structure of sediment microorganisms follows the changes in the external environment. Here, the pollutant indicators, including nitrogen, phosphorus, and heavy metals in the overlying water and sediment of 29 RBOWB in Dongming County of Heze City were measured, respectively. Combined with Illumina sequencing results, the composition and diversity characteristics of sediment bacterial communities in RBOWB and their correlation with environmental factors were further analyzed. The experimental results showed a wide distribution of pollutants in both of the overlying water and sediment in the RBOWB of this region. Compared with agricultural non-point source pollution, the concentrations of nitrogen and phosphorus pollutants in the overlying water with domestic sewage as the main source of pollution were 3.1 and 1.5 times higher than those of agricultural non-point source pollution, respectively. In addition, the contents of heavy metals in the sediments of RBOWB were generally lower than the soil element background value in Heze City. The dominant bacteria phyla in the sediments of the RBOWB were Proteobacteria, Actinobacteria, Chloroflexi, Firmicutes, and Acidobacteria, and the total abundance of these five dominant phyla accounted for 70.3%-83.6% of all sequences. The dominant classes were γ -Proteobacteria, α -Proteobacteria, Anaerolineae, and Actinobacteria. The dominant genera were Thiobacillus and Pseudarthrobacter . Moreover, Spearman correlation analysis showed that the environmental factors of DO, COD, TN, TP, and organic matter exerted significant effects( P <0.05) on sediment bacterial genera in RBOWB, and sediment bacterial community richness was significantly influenced by TN( P <0.05). The above results provided the microbiological knowledge for treating RBOWB.

In this study, two halophilic bacteria were isolated from activated sludge in the epoxy wastewater treatment system. The strains were identified, and the growth and degradation characteristics were investigated. Strain J1 and J2 was identified respectively by morphological observation and 16S rDNA sequence alignment analysis. It was found that both strains belong to the Bacillus genus (Bacillus sp.) and branch Bacillus (Virgibacillus sp.). The optimized growth condition of strain J1 and J2 in the high salt CM culture medium was as follows: solution temperature 30 degrees C, pH 7.0 and 5-50 g x L(-1) of NaCl. Furthermore, the best degradation condition of the organic epoxy wastewater was: temperature 30 degrees C, pH 7.0 and NaCl concentration 30 g x L(-1). When the volume ratio of bacterial suspension mixture of J1 and J2 was 2:1 and the inoculum size of the composite strains was 10%, the highest COD removal efficiency was achieved in the epoxy wastewater treatment.