Toxic and repellent effects of the essential oil from Asarum heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. were evaluated against Lasioderma serricorne and Liposcelis bostrychophila. The essential oils (EOs) from roots (ER) and leaves (EL) of A. heterotropoides were obtained separately by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS) analysis. Major components of ER and EL included methyleugenol, safrole, and 3,5-dimethoxytoluene. Both ER and EL of A. heterotropoides showed certain toxicity and repellency against L. serricorne and L. bostrychophila. 3,5-Dimethoxytoluene, methyleugenol, and safrole were strongly toxic via fumigation to L. serricorne (LC50 = 4.99, 10.82, and 18.93 mg/L air, respectively). Safrole and 3,5-dimethoxytoluene possessed significant fumigant toxicity against L. bostrychophila (LC50 = 0.83 and 0.91 mg/L air, respectively). The three compounds all exhibited potent contact toxicity against the two insect species. Here, the EL of A. heterotropoides was confirmed to have certain toxicity and repellency against stored product insects, providing a novel idea for the comprehensive use of plant resources.
This research discusses the impact of the perception of video images and online word of mouth on tourists’ travel intentions. A survey of 390 users who watched travel videos on short-video platforms was conducted using structural equation modeling. The results are as follows. First, the perception of video images can significantly affect tourists’ intention to visit the destinations. Second, as a mediating variable, online word of mouth can enhance the positive effects of the perception of video images on tourists’ travel intentions. Third, gender had a positive moderating effect, which was particularly obvious in the relationship between the perception of video images and online word of mouth. This research provides a theoretical basis for the utility of tourism-related short videos, which can help stimulate tourists’ intention to visit promoted destinations.
After analysis of the data from Dalian bus IC card database, the paper propose an optimization algorithm for bus scheduling. By introducing an artificial immune algorithm based on information entropy, the optimal or the quasi-optimal solution to this multi-variable and non-linear problem of bus scheduling can be found efficiently. The experiment results demonstrate that the optimal bus departure intervals under different time periods can be obtained to adjust bus timetable conveniently, which help to adjust bus timetable dynamically.
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