54 research outputs found
The Curriculum and Education System of American Higher Tourism Education Taking the School of Hotel Administration at Cornell University as an Example
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Optimization of maritime emergency base placement for inland waterway accident response: a case study of the Yangtze River
No full textAs the construction of maritime emergency rescue systems worldwide increases, there are more maritime emergency bases along the Yangtze River, yet the mismatch between the layout of these bases and the demand for maritime emergency rescue has emerged. This paper analyzes the impact of marine transportation accident characteristics on emergency demand, uses the CRITIC assignment method to quantify the weights of accident characteristics, and classifies accident levels via the WRSR method. It introduces the equivalent accident number method’s research idea and employs the DBSCAN algorithm to cluster and analyze accident blackspots on the Yangtze River mainline. Based on identified blackspots and multiple siting model characteristics, an emergency base siting model considering accident emergency demand is proposed and solved with LINGO. Taking the accident cases in the Nanjing section of the Yangtze River from 2019 to 2021 as an example, a siting scheme meeting the emergency demand of the Yangtze River trunk line is obtained. Model validation results show that at least three maritime emergency facilities need to be built in the Nanjing section to ensure comprehensive coverage of main navigable waters. As the number of emergency facilities grows, their comprehensive emergency response time decreases and multiple coverage of high-risk waters can be achieved. Decision-makers can formulate emergency facility layout plans based on the proposed siting method
Density Functional Theory Study of the Oxygen Reduction Reaction on Metalloporphyrins and Metallophthalocyanines
No full textIn this paper, density functional theory is applied to study the electrochemical reduction of oxygen on iron phthalocyanine (FePc), iron porphyrin (FeP), cobalt phthalocyanine (CoPc), and cobalt porphyrin (CoP). According to the calculation results, for the four metal macrocyclic complexes, O-2 will not directly be cleaved without the cooperation of hydrogen. In the reduction process, on FePc or FeP, H2O2 does not form as an intermediate, and O-2 is reduced to H2O, while on CoPc or CoP, O-2 is just reduced to H2O2. The reason why the oxygen reduction ability of FePc or FeP is higher than that of CoPc or CoP, respectively, is that the energy level of the highest-occupied 3d orbital of the former is higher than that of the later. The high energy level of the metal 3d orbital leads to the strong ability of oxygen reduction.Chemistry, PhysicalNanoscience & NanotechnologyMaterials Science, MultidisciplinarySCI(E)33ARTICLE199511-951711
Comparing the perception of emergency remote teaching experience between physics and nonphysics students
No full textA significant proportion of universities throughout the world switched from conventional face-to-face course delivery to emergency remote teaching (ERT) in response to the pervasive COVID-19 outbreak. A series of challenges are faced by both teachers and students as a result of the rapid and abrupt switch to ERT. Within the context of ERT, physics courses encounter certain challenges in contrast to certain liberal arts courses. In particular, this study sought to determine whether physics students and nonphysics students had diverse levels of flow experience and cognitive load when applying ERT during the global pandemic period. Furthermore, this study examined whether ERT for physics students varied depending on gender and educational level. Following the completion of their ERT courses at the end of both the Spring semester of 2020 and the Fall semester of 2022, a total of 1073 participants, including both physics majors and nonphysics majors, participated in our research. From the result, physics students had better performance in the flow experience encompassing its three constructs: enjoyment, engagement, and control. Physics students demonstrated a higher germane cognitive load and a lower extraneous cognitive load when compared to nonphysics students. Moreover, a considerably higher extraneous cognitive load was observed among male physics students than among their female counterparts during the ERT. Nonetheless, physics students at undergraduate and graduate levels did not significantly differ in their flow experiences or cognitive load. Overall, physics majors had a more positive perception of their ERT learning experience, and the impact of ERT on physics students was significantly less detrimental
Knowledge-Mapping Analysis of Urban Sustainable Transportation Using CiteSpace
No full textWith the accelerating process of global urbanization, environmental protection has become a hot issue for researchers, practitioners, and policy makers, with such questions as how to make urban transportation markedly sustainable to meet the pace of sustainable economic and social growth. This study visualizes and quantifies the extant publications on urban sustainable transportation research on Web of Science using CiteSpace for a wide range of research topics, including the intellectual structure, development, and evolution of urban sustainable transportation. First, this study presents the characteristics of a number of published papers in relevant fields and time stages, including publication in journals, co-occurrence of keywords, co-occurrence of disciplines and fields, and co-occurrence of the literature through network analysis. This study identifies the basic research contents and high-frequency knowledge contents of urban sustainable transportation. Second, this research analyzes the authors’ cooperation, national cooperation, and research institute cooperation networks. This study identifies the most influential authors, research institutions, and countries. Lastly, this study identifies the research frontiers and trend themes from 1991 to 30 September 2022 through co-citation clustering and research on burst detection, a combination of bibliometric methods, and a systematic review. Accordingly, this study demonstrates the research progress in this field from the perspectives of multiple themes, such as land development and utilization, sustainable transportation systems, low-carbon paths, public transport, electric vehicles, sharing modes, traveler behavior, and smart cities. These aspects provide readers with a preliminary understanding of the development of urban sustainable transportation, indicating that multidisciplinary, multiprofessional, and multiangle cooperation and analysis will become the dominant trend in this field
The Underlying Mechanism Involved in Gefitinib Resistance and Corresponding Experiment Validation in Lung Cancer
No full textBackground. Gefitinib resistance remains a major problem in the treatment of lung cancer. However, the underlying mechanisms involved in gefitinib resistance are largely unclear. Methods. Open-accessed data of lung cancer patients were downloaded from The Cancer Genome Atlas Program and Gene Expression Omnibus databases. CCK8, colony formation, and 5-ethynyl-2′-deoxyuridine assays were utilized to evaluate the cell proliferation ability. Transwell and wound-healing assays were utilized to evaluate the cell invasion and migration ability. Quantitative real-time PCR was utilized to detect the RNA level of specific genes. Results. Here, we obtained the expression profile data of wild and gefitinib-resistant cells. Combined with the data from the TCGA and GDSC databases, we identified six genes, RNF150, FAT3, ANKRD33, AFF3, CDH2, and BEX1, that were involved in gefitinib resistance in both cell and tissue levels. We found that most of these genes were expressed in the fibroblast of the NSCLC microenvironment. Hence, we also comprehensively investigated the role of fibroblast in the NSCLC microenvironment, including its biological effect and cell interaction. Ultimately, CDH2 was selected for further analysis for its prognosis correlation. In vitro experiments presented the cancer-promoting role of CDH2 in NSCLC. Moreover, cell viability detection showed that the inhibition of CDH2 could significantly decrease the IC50 of gefitinib in NSCLC cells. GSEA showed that CDH2 could significantly affect the pathway activity of PI3K/AKT/mTOR signaling. Conclusions. This study is aimed at investigating the underlying mechanism involved in gefitinib resistance to lung cancer. Our research has improved researchers’ understanding of gefitinib resistance. Meanwhile, we found that CDH2 could lead to gefitinib resistance through PI3K/AKT/mTOR signaling
Inventory pooling and pricing decisions in multiple markets with strategic customers
No full textThis study considers the pricing and inventory decisions for the retailer selling in multiple markets with strategic customers. The impact of strategic customer behavior on inventory pooling is examined. The equilibrium decisions, in which strategic customers tend to purchase early, are subsequently characterized in the pooled/non-pooled systems. Our results highlight the role of the strategic customer in each market. Compared with myopic customers, the retailer is prone to reduce its inventory for strategic customers. The retailer’s optimal inventory for high-profit products is lower in the pooled system than in the non-pooled system. However, the result is reversed for low-profit products. The analytical and numerical results simultaneously demonstrate that, in the high-profit condition, the retailers’ inventory in the pooled system increases with the correlation coefficient of different markets, while the retailers’ profit decreases with the correlation coefficient. There is an opposite relationship in the low-profit condition. When the markets are less correlated, the retailer owns low inventory but high profit. Moreover, the retailers’ profit is always higher in the pooled system than in the non-pooled system
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