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This study was designed to explore the effects of problem-based learning (PBL) strategies on the attitudes of female senior high school students toward integrated knowledge learning in science, technology, engineering, and mathematics (STEM). Content analysis and focus group methods were adopted as the research processes. Data and information about the STEM internet platform, an attitude scale and the contents of interviews were also collected for analysis. The subjects were 10th grade students at a girls' senior high school who volunteered to organize teams for a Solar Electric Trolley Contest. A total of 40 students were grouped into 18 teams. The results of the study indicate: (1) that PBL strategies can be helpful in enhancing students' attitudes toward STEM learning and the exploration of future career choices; (2) that the PBL teaching strategy helped to lead students step by step toward completing the contest's mission and to experience the meaning of integrated STEM knowledge; (3) that not only that students can actively apply engineering and science knowledge, but also that students tend to gain more solid science and mathematics knowledge through STEM learning in PBL; and (4) that PBL can enhance

The Madden–Julian oscillation (MJO) excites strong variations in extratropical atmospheric circulations that have important implications for subseasonal-to-seasonal (S2S) prediction. A previous study showed that particular MJO phases are characterized by a consistent modulation of geopotential heights in the North Pacific and adjacent regions across different MJO events, and demonstrated that this consistency is beneficial for extended numerical weather forecasts (i.e., lead times of two weeks to one month). In this study, we examine the physical mechanisms that lead some MJO phases to have more consistent teleconnections than others using a linear baroclinic model. The results show that MJO phases 2, 3, 6, and 7 consistently generate Pacific–North American (PNA)-like patterns on S2S time scales while other phases do not. A Rossby wave source analysis is applied and shows that a dipole-like pattern of Rossby wave source on each side of the subtropical jet can increase the pattern consistency of teleconnections due to the constructive interference of similar teleconnection signals. On the other hand, symmetric patterns of Rossby wave source can dramatically reduce the pattern consistency due to destructive interference. A dipole-like Rossby wave source pattern is present most frequently when tropical heating is found in the Indian Ocean or the Pacific warm pool, and a symmetric Rossby wave source is present most frequently when tropical heating is located over the Maritime Continent. Thus, the MJO phase-dependent pattern consistency of teleconnections is a special case of this mechanism.

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