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This paper conducts a discourse analysis of Chinese tourist writings about Africa on the most popular Chinese online tourist forum, Mafengwo (hornet's nest). By examining 2,950 travelogues collected online, our research finds that Chinese tourists' conceptions of Africa are mainly built through 5 frames, including the exotic frame, the adventurous frame, the poverty frame, the China's engagement frame, and the affection frame that describe Africa as a remote, exotic, adventurous, dangerous, miserable, and backward place compared to a modern China that strongly supports Africa's development. Much tourist writing corresponds with the official Chinese geopolitical narrative of China-Africa relations that perceives China itself as a peacefully rising power who would also like to help developing others like Africa. However, we also find that some Chinese tourists' descriptions of Africa fit uneasily into the official Chinese geopolitical conceptions, in which they demonstrate affection for Africa, but only in regard to its Western aspects, e.g., architecture, food, activities. One contribution of this study is providing a bottom-up Chinese citizenry discourses and cultural experiences of Africa, and with this empirical analysis it updates theories of everyday Chinese geopolitics of tourism. We think this study is unique in that we have broadened the understanding of both official and citizenry Chinese geopolitical conceptions and their (dis)connections, in particular from the everyday encounter between geopolitics and tourism, which also sets a frame for comprehending Chinese citizenry geopolitical conceptions of the outside 'other'. [ABSTRACT FROM AUTHOR]

In this paper, the effects of rare earth elements on the bonding strength and stability of TiC/fcc-Fe interface are explored by using the first-principles method based on density functional theory. The results show that the Ti terminal is more stable than the C terminal in the process of forming the interface. The alloying elements tend to segregate at position 2 on the side of fcc-Fe. The segregation of Mo, Nb, Cr and Ce alloying elements increases the interatomic electron cloud enrichment and consumption between the interfaces and enhances the Fe–Ti interactions. The d orbitals of Mo, Nb, Cr and Ce and f orbitals of Ce have strong hybridization with Fe-d orbitals and Ti-d orbitals electrons near the Fermi energy level, indicating an increase in bonding strength and stability of the interfaces. When Fe atoms are replaced by W, Ni and Al atoms, the covalent bond strength between interfacial atoms is reduced, thus weakening the interfacial bonding strength. This provides solid theoretical foundation with regard to further application in austenitic heat-resistant steel fields. [ABSTRACT FROM AUTHOR]

Summary: The elasticity and pay‐as‐you‐go features of cloud computing are popular with customers, and more and more workflow applications are migrating to cloud platforms. Many workflow scheduling algorithms aim to obtain minimal rental costs. However, most of the existing research assumes that task execution time is deterministic. In fact, due to the performance fluctuations of VMs, the task execution time is uncertain before scheduling. Furthermore, many works ignore the cost savings given by multi‐cloud systems. To this end, this paper provides a scheduling framework for real‐time workflows. The framework includes four main components: the workflow analyzer, task pool, task allocation controller, and resource manager. Then based on the framework, we propose the RWSMC heuristic algorithm. The algorithm's goal is to minimize the total rental cost while satisfying the deadline constraints and ensuring the reliability of task execution. The RWSMC algorithm reduces the cost by selecting the appropriate billing mechanism based on the task's execution time and mitigates the impact of uncertain execution time by scheduling the task to the VM with the shortest predicted start time. Simulation experiments demonstrate that our proposed algorithm outperforms three recent state‐of‐the‐art scheduling algorithms in the total rental cost, deadline violation rate, and VM resource utilization. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the diagnostic performance of coronary CT angiography (CTA)-based quantitative flow ratio (QFR), namely CT-QFR, and compare it with invasive coronary angiography (ICA)-based Murray law QFR (μQFR), using fractional flow reserve (FFR) as the reference standard. Patients who underwent coronary CTA, ICA and pressure wire-based FFR assessment within two months were retrospectively analyzed. CT-QFR and μQFR were computed in blinded fashion and compared with FFR, all applying the same cut-off value of ≤0.80 to identify hemodynamically significant stenosis. Paired comparison between CT-QFR and μQFR was performed in 191 vessels from 167 patients. Average FFR was 0.81 ​± ​0.10 and 42.4% vessels had an FFR ≤0.80. CT-QFR had a slightly lower correlation with FFR compared with μQFR, although statistically non-significant (r ​= ​0.87 versus 0.90, p ​= ​0.110). The vessel-level diagnostic performance of CT-QFR was slightly lower but without statistical significance than μQFR (AUC ​= ​0.94 versus 0.97, difference: −0.03 [95%CI: −0.00-0.06], p ​= ​0.095), and substantially higher than diameter stenosis by CTA (AUC difference: 0.17 [95%CI: −0.10-0.23], p ​< ​0.001). The patient-level diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio for CT-QFR to identify FFR value ​≤ ​0.80 was 88%, 90%, 86%, 86%, 91%, 6.59 and 0.12, respectively. The diagnostic accuracy of CT-QFR was 84% in extensively calcified lesions, while in vessels with no or less calcification, CT-QFR showed a comparable diagnostic accuracy with μQFR (91% versus 92%, p ​= ​0.595). Intra- and inter-observer variability in CT-QFR analysis was −0.00 ​± ​0.04 and 0.00 ​± ​0.04, respectively. Performance in diagnosis of hemodynamically significant coronary stenosis by CT-QFR was slightly lower but without statistical significance than μQFR, and substantially higher than CTA-derived diameter stenosis. Extensively calcified lesions reduced the diagnostic accuracy of CT-QFR. [ABSTRACT FROM AUTHOR]

Background: Orobanchaceae is the only flowering plant family with species from free-living nonparasite, hemi-parasite to holoparasite, making it an ideal system for studying the evolution of parasitism. However, both plastid and mitochondrial genome have been sequenced in only few parasitic species in Orobanchaceae. Therefore, further comparative study is wanted to investigate the impact of holoparasitism on organelle genomes evolution between close relatives. Here, we sequenced organelle genomes and transcriptome of holoparasitic Christisonia kwangtungensis and compared it with its closely related groups to analyze similarities and differences in adaption strategies to the holoparasitic lifestyle. Results: The plastid genome of C. kwangtungensis has undergone extensive pseudogenization and gene loss, but its reduction pattern is different from that of Aeginetia indica, the close relative of C. kwangtungensis. Similarly, the gene expression detected in the photosynthetic pathway of these two genera is different. In Orobanchaceae, holoparasites in Buchnereae have more plastid gene loss than Rhinantheae, which reflects their longer history of holoparasitism. Distinct from severe degradation of the plastome, protein-coding genes in the mitochondrial genome of C. kwangtungensis are relatively conserved. Interestingly, besides intracellularly transferred genes which are still retained in its plastid genome, we also found several horizontally transferred genes of plastid origin from diverse donors other than their current hosts in the mitochondrial genome, which probably indicate historical hosts. Conclusion: Even though C. kwangtungensis and A. indica are closely related and share severe degradation of plastome, they adapt organelle genomes to the parasitic lifestyle in different ways. The difference between their gene loss and gene expression shows they ultimately lost photosynthetic genes but through different pathways. Our study exemplifies how parasites part company after achieving holoparasitism. [ABSTRACT FROM AUTHOR]