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This study examined and compared the intended mathematics curricula according to topic coverage, focus, coherence, and learning progression in grades 1-12 within China and the province of Ontario, Canada. The findings show that the overall topics in the two curricula are similar: Chinese curriculum covers 78 topics out of 79 while the Ontario curriculum covers 76. The two curricula also share a similar general sequence such as topics for transfer stages from numbers to functions by starting with constant mathematics, then variable mathematics, and finally functions. However, the detailed topic design of the 2 curricula differs markedly. The Chinese curriculum includes few topics in each year, a short duration or span of each topic, and a fast-paced topic progression. The Ontario curriculum, in contrast, includes more topics each year, longer duration of many topics, and a small pace of topic progression in grades 1-8 and a fast pace of topic progression in grades 9-12. Because of different curriculum designs in grades 1-12, the intended curriculum may influence students' cognitive structures of mathematics, learning behavior and thinking, learning efficiency and achievement, and teachers' professional development. This calls for more refined and advanced research on the defined list of topics, topic organization, and terms to study curriculum in order to increase student learning opportunities.

Summary: Rice false smut caused by Ustilaginoidea virens is a devastating rice (Oryza sativa) disease worldwide. However, the molecular mechanisms underlying U. virens–rice interactions are largely unknown. In this study, we identified a secreted protein, Uv1809, as a key virulence factor. Heterologous expression of Uv1809 in rice enhanced susceptibility to rice false smut and bacterial blight. Host‐induced gene silencing of Uv1809 in rice enhanced resistance to U. virens, suggesting that Uv1809 inhibits rice immunity and promotes infection by U. virens. Uv1809 suppresses rice immunity by targeting and enhancing rice histone deacetylase OsSRT2‐mediated histone deacetylation, thereby reducing H4K5ac and H4K8ac levels and interfering with the transcriptional activation of defence genes. CRISPR‐Cas9 edited ossrt2 mutants showed no adverse effects in terms of growth and yield but displayed broad‐spectrum resistance to rice pathogens, revealing a potentially valuable genetic resource for breeding disease resistance. Our study provides insight into defence mechanisms against plant pathogens that inactivate plant immunity at the epigenetic level. [ABSTRACT FROM AUTHOR]

As the performance requirements of insulated gate bipolar transistors (IGBTs) in various fields of power electronic systems are increasing, the IGBT power module package structure, aging mechanism analysis, and selection of health state characteristic parameters are of great significance to ensure the normal operation of power systems. At present, research on the aging failure of welded IGBT modules is relatively comprehensive and can be divided into chip aging failure and package aging failure according to their failure parts. However, there is some research on the relationship between aging failure and the characteristic quantity of power modules, but no definite system has been formed. Therefore, in this paper, the packaging structure of the solder-type IGBT modules and the aging mechanism caused by different aging reasons were summarized. Moreover, the health status monitoring of solder-type IGBT modules from the junction temperature, bonding line, solder layer, and package insulation aging health status monitoring and its quantitative assessment research progress was analyzed in detail. Also, the health state evaluation index system of the solder-type IGBT modules was completed on the basis of voltage, current, thermal, insulation parameters, and other characteristic quantities. Finally, based on the analysis of domestic and international research problems, the development trend and direction of the condition monitoring technology of solder-type IGBT modules is foreseen. The research on condition monitoring for welded IGBT module technology has a certain significance. [ABSTRACT FROM AUTHOR]

Based on the alkali resistance of polyester/TGIC, polyester/HAA, polyester/epoxy and polyurethane powder coatings, the hydroxy-terminated polyester resin is modified by means of using some monomer containing steric groups and improving the crosslinking density. The results show that polyester/TGIC and polyester/HAA systems have the worst alkali resistance, polyester/epoxy system is slightly better, and polyurethane system is the best. The modified hydroxy-terminated polyester resin has good mechanical properties, adhesion, boiling water resistance and excellent alkali resistance. At 30 °C, soaked by 50%wt NaOH for 96 h, the gloss retention rate is 77% with no cracking and other defects. At 60 °C, soaked by 50%wt NaOH for 22 h, the gloss retention rate is 60% with no cracking and other defects. [ABSTRACT FROM AUTHOR]

Rice ARGONAUTE2 (OsAGO2) is a core component of the rice RNA‐induced silencing complex (RISC), which is repressed by Magnaporthe oryzae (M. oryzae) infection. Whether and how OsAGO2‐mediated gene silencing plays a role in rice blast resistance and which sRNAs participate in this process are unknown. Our results indicate that OsAGO2 is a key immune player that manipulates rice defense responses against blast disease. OsAGO2 associates with the 24‐nt miR1875 and binds to the promoter region of HEXOKINASE1 (OsHXK1), which causes DNA methylation and leads to gene silencing. Our multiple genetic evidence showed that, without M. oryzae infection, OsAGO2/miR1875 RISC promoted OsHXK1 promoter DNA methylation and OsHXK1 silencing; after M. oryzae infection, the reduced OsAGO2/miR1875 led to a relatively activated OsHXK1 expression. OsHXK1 acts as a positive regulator of blast disease resistance that OsHXK1‐OE rice exhibited enhanced resistance, whereas Cas9‐Oshxk1 rice showed reduced resistance against M. oryzae infection. OsHXK1 may function through its sugar sensor activity as glucose induced defense‐related gene expression and reactive oxygen species (ROS) accumulation in Nipponbare and OsHXK1‐OE but not in Cas9‐Oshxk1 rice. OsAGO2 itself is delicately regulated by OsPRMT5, which senses M. oryzae infection and attenuates OsAGO2‐mediated gene silencing through OsAGO2 arginine methylation. Our study reveals an OsPRMT5‐OsAGO2/miR1875‐OsHXK1 regulatory module that fine tunes the rice defense response to blast disease. [ABSTRACT FROM AUTHOR]