Perception of strigolactones and the coordinated phytohormonal regulation on rice (Oryza sativa) tillering is affected by endogenous ascorbic acid.

Phytohormones play a key role in regulating tiller number. Ascorbic acid (Asc)-phytohormone interaction plays a pivotal role in the regulation of senescence. We analysed the relationship between Asc and the enzyme concentrations and gene transcript abundances related to the signal perception of strigolactones (SLs), the contents of four phytohormones (abscisic acid, ABA; jasmonic acid, JA; indole acetic acid, IAA; cytokinin, CTK), the enzyme concentrations and gene transcript abundances related to the synthesis or transportation of these four phytohormones. Our results showed that Asc deficiency leads to the upregulation of enzyme concentrations, gene transcript abundances related to the SL signal perception, ABA synthesis and IAA transport. The altered level of Asc also leads to a change in the contents of ABA, JA, IAA and CTK. These findings support the conclusion that Asc or Asc/DHA play an important role in the signal perception and transduction of SLs, and Asc may affect the coordinated regulation of SL, IAA and CTK on rice (Oryza sativa ) tillering.

The design of experimental courses in safety culture.

To promote the application of safety culture in experimental courses that educate safety engineering majors and help students understand the concept and meaning of safety culture more deeply, this paper designed 10 experimental courses in safety culture from the perspective of the definition of safety culture using literature co-occurrence analysis and certain review methods. First, according to the literature research and keyword analysis, the definitions of safety culture can currently be divided into three categories: "the embodiment of safety concepts"; "the synthesis of safety concepts and behaviors"; and "the comprehensive theory of safety culture". Then, based on the study of the definitions, 10 experimental courses were designed and the basis was listed. The final results include 10 safety culture experiments and the relationship between them. The purpose, significance, contents and steps of the 10 experiments are designed to help students better understand the meaning of safety culture and try to transform scientific research achievements of safety culture into teaching.

Analysis of Human Factors Relationship in Hazardous Chemical Storage Accidents.

Human factors are important causes of hazardous chemical storage accidents, and clarifying the relationship between human factors can help to identify the logical chain between unsafe behaviors and influential factors in accidents. Therefore, the human factor relationship of hazardous chemical storage accidents was studied in this paper. First, the human factors analysis and classification system (HFACS), which originated from accident analysis in the aviation field, was introduced. Since some items were designed for aviation accident analysis, such as the item "Crew Resource Management", it is not fully applicable to the analysis of hazardous chemical storage accidents. Therefore, this article introduced some modifications and changes to make the HFACS model suitable for the analysis of hazardous chemical storage accidents. Based on the improved HFACS model, 42 hazardous chemicals storage accidents were analyzed, and the causes were classified. After analysis, we found that under the HFACS framework, the most frequent cause of accidents is resource management, followed by violations and inadequate supervision, and finally the organizational process and technological environment. Finally, according to the statistical results for the various causes of accidents obtained from the improved HFACS analysis, the chi-square test and odds ratio analysis were used to further explore the relevance of human factors in hazardous chemical storage accidents. The 16 groups of significant causal relationships among the four levels of factors include resource management and inadequate supervision, planned inappropriate operations and technological environment, inadequate supervision and physical/mental limitations, and technological environment and skill-based errors, among others.

Identification and expression analysis of a doublesex1 gene in Daphnia pulex during different reproductive stages.

The gene doublesex (dsx) has shown deep conservation in the sex determination in many organisms. Environmental stimuli initiate a switch in the reproductive strategy of Daphnia pulex from asexual to sexual reproduction; however, occasionally, changes in environmental conditions will not lead to this transition. So study genetic responses to environmental stimuli and the molecular basis for the switch of reproductive stages are urgently needed. Therefore, we isolated and sequenced a D. pulex doublesex1 gene (Dpdsx1) and analyzed its expression and location by quantitative polymerase chain reaction (qPCR) and whole-mount in situ hybridization in D. pulex during different stages of reproduction. The predicted amino acid sequence has 335 amino acids that contained one DM domain and one dimerization domain, which is characteristic of insect orthologs of Dsx. Real-time PCR showed that Dpdsx1 expression decreased significantly (P < 0.05) in different reproductive stages in the following order: male, parthenogenetic female, ephippial female, resting egg, and juvenile female. Whole-mount in situ hybridization revealed that Dpdsx1 is expressed in the first antennae, first thoracic limb and compound eye in males, whereas expression levels in the corresponding sites of parthenogenetic and ephippial females were relatively weak. Dpdsx1 could not be detected in the gonads of males or ephippial and parthenogenetic females. Taken together, these different reproductive stages' and sex specific expression patterns are regulated temporally and spatially. We speculate that Dpdsx1 may involve in switching different stages of reproduction and in sexual differentiation in D. pulex.