Fermentation quality, aerobic stability, and microbiome structure and function of Caragana korshinskii silage inoculated with/without Lactobacillus rhamnosus or Lactobacillus buchneri

Caragana korshinskii is a forage shrub species with high-protein content that has been extensively used to alleviate feed shortages for ruminants in northern China. Herein, we investigated the effects of Lactobacillus rhamnosus and Lactobacillus buchneri on the fermentation quality, aerobic stability, and microbiome composition and the predicted functional characteristics of C. korshinskii silage. C. korshinskii silages were inoculated with and without L. rhamnosus or L. buchneri. After 14 and 56 days of ensiling, the aerobic stability was determined. The results revealed that after 14 and 56 days of ensiling, L. rhamnosus- and L. buchneri-inoculated silage exhibited increased acetic acid and lactic acid contents, whereas the pH and 2,3-butanediol and butyric acid contents were decreased compared with those of the control silage. The control silages that were opened at 14 and 56 d, deteriorated during the aerobic stability test, whereas silages inoculated with L. rhamnosus and L. buchneri did not exhibit any aerobic deterioration. The control silage showed an increased Clostridium and Bacillus abundance, whereas Lactobacillus abundance decreased compared with L. rhamnosus- and L. buchneri-inoculated silages, following the 7 days of aerobic exposure. The fermentation parameters were associated with microbial communities, including Lactobacillus, Pedicoccus, Weissella, Clostridium, and Bacillus. Carbohydrate and amino acid metabolisms in the control silage decreased after 7 days of aerobic exposure compared with lactic acid bacteria-inoculated silages. To conclude, next-generation sequencing combined with 16S ribosomal RNA gene-predicted functional analyses might provide new information about the silage quality during fermentation and the aerobic stability

Characterizing and assessing collective responsibility in computer-supported collaborative inquiry environments

Collective responsibility, a responsibility for successful collaboration, has received increasing attention in current educational reforms, especially in the field of computer-supported collaborative learning (CSCL). It emphasizes the shift of social and cognitive responsibility for learning from the teacher to students, as well as the distribution of this responsibility among all participants. However, students often lack the awareness and capability of taking collective responsibility, especially in the contexts of Chinese classrooms. This study investigates collective responsibility enacted by Chinese undergraduates engaged in collaborative inquiry discourse on an online platform called Knowledge Forum®, where two social configurations, fixed small groups and opportunistic collaboration, were combined. Four research questions addressed in the study are: 1) What characterizes collective responsibility among participants in a CSCL environment? 2) How do dynamics of collective responsibility mediate student-centered online discourse? 3) What are the roles of collective responsibility in students’ collaborative and individual understanding of knowledge? 4) What are students’ perceptions and experiences of enacting collective responsibility in the designed CSCL environment? The research includes two case studies, each of which was conducted in one intact class wherein online discourse was integral to an introductory research methods course, with support of a CSCL environment informed by principle-based design. Study One includes 27 participants, which explores the characteristics and dynamics of collective responsibility, addressing the first two research questions. Study Two includes 20 participants, which was conducted in the following academic year, addressing the four research questions. Special attention has been paid to examinations of the characteristics and dynamics of collective responsibility, the influences it exerts on the students’ knowledge understanding, their perceptions and interpretation about learning experience. Data sources in Study One include quantitative and qualitative data from online discourse, while Study Two consists of multiple data collected from students’ online discourse, focus group interviews, and assignment tasks. The characterization of collective responsibility based on social network analysis and content analysis reveals that the two undergraduate classes took relatively high levels of social and cognitive responsibility with regard to three dimensions: social awareness, complementary contributions, and distributed engagement. A multi-faceted examination of online discourse within and across different social configurations found that the participants were capable of enacting greater collective responsibility throughout the course despite some constraints. The analyses uncovered that collaborative and individual understanding were advanced along with the development of collective responsibility, as reflected by increasing note reading interactions and shared responsibility for responding more high levels of questions and ideas during online discourse. Further interview data analysis identified social and cognitive factors that affect the enactment of collective responsibility for collaborative inquiry. Theoretically speaking, this study offers insight into the characteristics and dynamics of collective responsibility taken over by students in CSCL environments. On the practical side, it contributes to the CSCL literature by providing empirical examples of incorporating online collaborative inquiry into regular Chinese undergraduate courses, through the incorporation of curriculum, pedagogy, and technology. It also introduces applicable methods in examining fine-grained dynamics of online discourse in CSCL studies from a methodological perspective.published_or_final_versionEducationDoctoralDoctor of Philosoph

Variation Characteristics of Ecosystem Water Use Efficiency and Its Response to Human Activity and Climate Change in Inner Mongolia

Water use efficiency (WUE) reflects the balance between carbon assimilation and water consumption in terrestrial ecosystems. Considering the fragile conditions of global water resources, the evaluation of regional WUE variation characteristics and response mechanisms is critical for promoting sustainable ecological development and water resource utilization. Based on gross primary productivity (GPP) and evapotranspiration (ET) datasets, combined with vegetation and meteorological data, this study examined the spatiotemporal variations, annual variation contribution rate, and driving mechanism of WUE in Inner Mongolia from 2001 to 2020. The main results are as follows: (1) The interannual and spatial variations of GPP, ET, and WUE all exhibited increasing trends, with WUE increasing in approximately 70% of the region and significantly increasing in 22.35% of pixels exhibiting a significant increase. Areas with the most significant increases were located in the Horqin sandy land and Mu Us sandy land. (2) The highest WUE values were observed in the summer season, followed by autumn and winter, and the lowest in spring. (3) Among all vegetation types, the typical steppe ecosystems contributed most to the interannual variability (IAV) of GPP, ET, and WUE, with values of 169.89%, 141.09%, and 193.42%, respectively. While the coniferous forest contributed least or negatively to GPP, ET, and WUE IAV, with values of −36.28%, 28.20%, and −32.86%, respectively. (4) The primary driver of WUE variation was found to be GPP, which contributed 59.36%, mainly in the central and western regions. The remaining 40.64% was attributable to ET, concentrated in the northeast region. (5) Human activities significantly affected WUE, with a contribution (about 53.52%) larger than that of climate change (nearly 46.48%). Increased precipitation improves vegetation WUE and is the most important climate factor influencing WUE variations. These findings will aid the formulation of vegetation protection and water resource management strategies in water-stressed areas

Variation Characteristics of Ecosystem Water Use Efficiency and Its Response to Human Activity and Climate Change in Inner Mongolia

Water use efficiency (WUE) reflects the balance between carbon assimilation and water consumption in terrestrial ecosystems. Considering the fragile conditions of global water resources, the evaluation of regional WUE variation characteristics and response mechanisms is critical for promoting sustainable ecological development and water resource utilization. Based on gross primary productivity (GPP) and evapotranspiration (ET) datasets, combined with vegetation and meteorological data, this study examined the spatiotemporal variations, annual variation contribution rate, and driving mechanism of WUE in Inner Mongolia from 2001 to 2020. The main results are as follows: (1) The interannual and spatial variations of GPP, ET, and WUE all exhibited increasing trends, with WUE increasing in approximately 70% of the region and significantly increasing in 22.35% of pixels exhibiting a significant increase. Areas with the most significant increases were located in the Horqin sandy land and Mu Us sandy land. (2) The highest WUE values were observed in the summer season, followed by autumn and winter, and the lowest in spring. (3) Among all vegetation types, the typical steppe ecosystems contributed most to the interannual variability (IAV) of GPP, ET, and WUE, with values of 169.89%, 141.09%, and 193.42%, respectively. While the coniferous forest contributed least or negatively to GPP, ET, and WUE IAV, with values of −36.28%, 28.20%, and −32.86%, respectively. (4) The primary driver of WUE variation was found to be GPP, which contributed 59.36%, mainly in the central and western regions. The remaining 40.64% was attributable to ET, concentrated in the northeast region. (5) Human activities significantly affected WUE, with a contribution (about 53.52%) larger than that of climate change (nearly 46.48%). Increased precipitation improves vegetation WUE and is the most important climate factor influencing WUE variations. These findings will aid the formulation of vegetation protection and water resource management strategies in water-stressed areas