The complex relationship between classroom emotions and EFL achievement in China

The present study adopted a mixed-method approach combining principles from Complex Dynamic Systems Theory and Positive Psychology to examine the interaction between Foreign Language Classroom Anxiety (FLCA) and Foreign Language Enjoyment (FLE) of 1,307 Chinese students, the single and combined effects of FLCA and FLE on self-perceived English proficiency and actual English achievement, and finally, the effect of EA on FLE and FLCA. Statistical analyses revealed negative correlations between FLCA and FLE in three groups at different levels of English achievement. Qualitative data from 64 participants threw further light on this complex relationship. Second, FLCA was found to be significantly negatively related to self-rated proficiency at all achievement groups while FLE was positively related. Similar significant relationships were also found between two classroom emotions and actual English achievement except in the low achievement group. Finally, qualitative data allowed us to investigate the possible causes for this relationship

Preliminary Characterization of Underground Hydrological Processes under Multiple Rainfall Conditions and Rocky Desertification Degrees in Karst Regions of Southwest China

Karst regions are widely distributed in Southwest China and due to the complexity of their geologic structure, it is very challenging to collect data useful to provide a better understanding of surface, underground and fissure flows, needed to calibrate and validate numerical models. Without characterizing these features, it is very problematic to fully establish rainfall–runoff processes associated with soil loss in karst landscapes. Water infiltrated rapidly to the underground in rocky desertification areas. To fill this gap, this experimental work was completed to preliminarily determine the output characteristics of subsurface and underground fissure flows and their relationships with rainfall intensities (30 mm h−1, 60 mm h−1 and 90 mm h−1) and bedrock degrees (30%, 40% and 50%), as well as the role of underground fissure flow in the near-surface rainfall–runoff process. Results indicated that under light rainfall conditions (30 mm h−1), the hydrological processes observed were typical of Dunne overland flows; however, under moderate (60 mm h−1) and high rainfall conditions (90 mm h−1), hydrological processes were typical of Horton overland flows. Furthermore, results confirmed that the generation of underground runoff for moderate rocky desertification (MRD) and severe rocky desertification (SRD) happened 18.18% and 45.45% later than the timing recorded for the light rocky desertification (LRD) scenario. Additionally, results established that the maximum rate of underground runoff increased with the increase of bedrock degrees and the amount of cumulative underground runoff measured under different rocky desertification was SRD > MRD > LRD. In terms of flow characterization, for the LRD configuration under light rainfall intensity the underground runoff was mainly associated with soil water, which was accounting for about 85%–95%. However, under moderate and high rainfall intensities, the underground flow was mainly generated from fissure flow

Research on a Modeling and Control Strategy for Interleaved Boost Converters with Coupled Inductors

Interleaved DC–DC converters have significant advantages in improving the capability of power converters, and coupling the filtering inductor of the converter could further increase the power density. However, existing modeling and controller designs are complex and require multiple sensors to be involved in the control, which is not conducive to engineering implementation and reducing production costs. In view of this problem, taking a two-phase interleaved boost converter with a coupled inductor as an example, the small-signal models of the converter are derived for the resistive load and constant voltage source load using the state averaging method. The total inductor current is engaged in the control as a feedback signal, avoiding the coupling effect of the inductor on increasing the complexity of the controller. Based on this, a double closed-loop controller is designed, and a prototype of the two-phase interleaved boost converter with coupled inductor is built. Only one current sensor and one voltage sensor are required to participate in the control. The effectiveness of the analysis and design in this paper are verified by experiments

Ecological Stoichiometric Characteristics of Two Typical Plantations in the Karst Ecosystem of Southwestern China

Reforestation has been widely adopted to restore soil fertility and ecosystem service function in the rocky desertification region of southwestern China. However, there has been limited research concerning the stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) and nutrient resorption rate of plantations in karst ecosystems. In this study, we selected plantations of Pinus yunnanensis Franch. (PY) and Eucalyptus maideni F. Muell. (EM) in Yunnan Province. The C, N, and P concentrations and the C:N:P stoichiometry in different soil layers (0–10 cm, 10–20 cm, and 20–30 cm) were examined. The nutrient limitation and nutrient resorption efficiency were also analyzed. The leaf C and N concentrations in the PY plantation were higher than that in the EM plantation; the P concentration demonstrated the opposite trend, both in green and senesced leaves. Soil C, N, and P concentrations in the EM plantation were much greater than in the PY plantation at all three depths and decreased with the depth of the soil. In addition, the high ratios of C:P, N:P, C:Available P, and N:Available P in soil coupled with the ratios of N:P in leaves indicate that the EM plantation has a greater P deficiency than the PY plantation. In the EM plantation, the relatively low P concentrations in senesced leaves indicates efficient TP (Total phosphorus) resorption, which highlights that the high reuse proficiency of P could have favored moderating P limitation in the karst ecosystem. This research aids in understanding the stoichiometric characteristics that mediate forest properties, and provides a basis for management of vegetation in karst ecosystems

The Riemerella anatipestifer M949_RS01035 gene is involved in bacterial lipopolysaccharide biosynthesis

Abstract In this study, the Riemerella anatipestifer mutant strain RA1062 was obtained by screening a random Tn4351 transposon mutant library. The mutant strain was unreactive with the anti-CH3 lipopolysaccharide monoclonal antibody, as demonstrated with an enzyme-linked immunosorbent assay, and its M949_RS01035 gene was inactivated. When cultured in trypticase soy broth, the late stage growth of the mutant RA1062 was significantly decreased. The mutant RA1062 was stained with crystal violet and presented a rough lipopolysaccharide phenotype, which differed from that of the wild-type strain CH3, suggesting that deletion of the M949_RS01035 gene resulted in defective lipopolysaccharide. Silver staining and Western blot analyses further confirmed that the RA1062 lipopolysaccharide had a deficiency in ladder-like binding pattern, as compared to lipopolysaccharide of the wild-type CH3 strain. In addition, the mutant RA1062 showed a higher susceptibility to complement-dependent killing, increased bacterial adhesion and invasion capacities to Vero cells, decreased blood bacterial loads, and attenuated virulence in infected ducks, when compared to the wild-type strain CH3. Moreover, RNA-Seq and real-time polymerase chain reaction analyses indicated that two genes were up-regulated and two were down-regulated in the mutant RA1062 genome. Furthermore, an animal protection experiment showed that immunization of ducks with inactivated RA1062 bacterin conferred effective cross-protection against challenge with the virulent R. anatipestifer serotypes 1, 2, and 10. This study presents evidence that the M949_RS01035 gene is involved in bacterial phenotype, virulence, and gene regulation in R. anatipestifer. The mutant strain RA1062 could be used as a cross-protective vaccine candidate

Riemerella anatipestifer M949_1360 Gene Functions on the Lipopolysaccharide Biosynthesis and Bacterial Virulence.

Riemerella anatipestifer causes septicemic and exudative diseases in poultry, resulting in major economic losses to the duck industry. Lipopolysaccharide (LPS), as an important virulence factor in Gram-negative bacteria, can be recognized by the immune system and plays a crucial role in many interactions between bacteria and animal hosts. In this study, we screened out one LPS defective mutant strain RAΔ604 from a random transposon mutant library of R. anatipestifer serotype 1 strain CH3, which did not react with the anti-CH3 LPS monoclonal antibody 1C1 in an indirect enzyme-linked immunosorbent assay. Southern blot analysis confirmed that the genome of RAΔ604 contained a single Tn4351 insert. Then, we found that the M949_1360 gene was inactivated by insertion of the transposon. Using silver staining and western blot analyses, we found that the LPS pattern of RAΔ604 was defective, as compared with that of the wild-type (WT) strain CH3. The mutant strain RAΔ604 showed no significant influence on bacterial growth, while bacterial counting and Live/dead BacLight Bacterial Viability staining revealed that bacterial viability was decreased, as compared with the WT strain CH3. In addition, the abilities of the mutant strain RAΔ604 to adhere and invade Vero cells were significantly decreased. Animal studies revealed that the virulence of the mutant strain RAΔ604 was decreased by more than 200-fold in a duck infection model, as compared with the WT strain CH3. Furthermore, immunization with live bacteria of the mutant strain RAΔ604 protected 87.5% ducks from challenge with R. anatipestifer serotype 1 strain WJ4, indicating that the mutant strain RAΔ604 could be used as a potential vaccine candidate in the future