Seeking the Masculine with the Feminine: P-6 Pre-Service Teachers’ Views on Teaching About the 2020 US Presidential Election

As democracies have deteriorated worldwide, understanding preservice teachers’ perceptions regarding teaching about the 2020 US presidential election helps teacher educators better guide them to make informed and intentional pedagogical decisions for democratic education. Through a survey study, we found that early childhood and elementary preservice social studies teachers did not express a strong degree of comfort teaching about the presidential election and were most comfortable teaching about matters of literacy and of political agreement

Spectral properties of photon pairs generated by spontaneous four wave mixing in inhomogeneous photonic crystal fibers

The photonic crystal fiber (PCF) is one of the excellent media for generating photon pairs via spontaneous four wave mixing. Here we study how the inhomogeneity of PCFs affect the spectral properties of photon pairs from both the theoretical and experimental aspects. The theoretical model shows that the photon pairs born in different place of the inhomogeneous PCF are coherently superposed, and a modulation in the broadened spectrum of phase matching function will appear, which prevents the realization of spectral factorable photon pairs. In particular, the inhomogeneity induced modulation can be examined by measuring the spectrum of individual signal or idler field when the asymmetric group velocity matching is approximately fulfilled. Our experiments are performed by tailoring the spectrum of pulsed pump to satisfy the specified phase matching condition. The observed spectra of individual signal photons, which are produced from different segments of the 1.9 m inhomogeneous PCF, agree with the theoretical predictions. The investigations are not only useful for fiber based quantum state engineering, but also provide a dependable method to test the homogeneity of PCF.Comment: to appear in Phys. Rev.

Tiazofurin inhibits oral cancer growth in vitro and in vivo via upregulation of miR-204 expression

Purpose: To investigate the effect of tiazofurin on proliferation and growth of oral cancer cells, and the associated mechanism(s) of action.Methods: The effect of tiazofurin on the cytotoxicity of SCC-VII and SCC-25 oral cancer cells were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, while cell apoptosis was determined by flow cytometry. Western blotting was used for assaying proteinexpressions.Results: Tiazofurin inhibited the viability of the oral cancer cells in a concentration-based manner (p < 0.05). Tiazofurin treatment at a dose of 2.0 μM reduced the proliferation of SCC-VII and SCC-25 cells to 25 and 22 %, respectively. Apoptosis was significantly increased in SCC-VII and SCC-25 cells by tiazofurin treatment, relative to untreated cells (p < 0 .05). Tiazofurin also increased the activation levels of caspase-3 and caspase-9 and downregulated the expressions of p-Akt and p-mTOR in the two cancer cell lines. Moreover, miR-204 expression was significantly promoted in the tiazofurin-treated cells, when compared to control (p < 0 .05). In SCC-VII cells, treatment with tiazofurin suppressed Factin expression, relative to control.Conclusion: These results demonstrate that tiazofurin inhibits the viability and proliferation of SCC-VII and SCC-25 cancer cells via induction of apoptosis and activation of caspase-3/caspase-9. Moreover, tiazofurin targets Akt/mTOR pathway, and upregulats the expressions of F-actin and miR-204 in the oral carcinoma cells. These findings suggest that tiazofurin has a potential for use as an effective treatment for oral cancer. Keywords: Oral cancer, Tiazofurin, Apoptosis, Caspase, Cytotoxicit

The unbalanced dragon: China's uneven provincial and regional FDI performance

This Perspective ranks all Chinese provinces in terms of their performance in attracting foreign direct investment, examines the reasons for the high unevenness of this performance and makes some policy suggestions on how to deal with it

不平衡的巨龙:中国不均衡的省市及地区FDI 业绩

从本文的角度出发，作者把中国各个省市地区，按照其吸引对外直接投资（FDI）的业绩来排序，研究了各个省市FDI业绩严重不均衡的原因，并就如何解决上述问题提出了一些政策上的建议

V2V Routing in VANET Based on Heuristic Q-Learning

Designing efficient routing algorithms in vehicular ad hoc networks (VANETs) plays an important role in the emerging intelligent transportation systems. In this paper, a routing algorithm based on the improved Q-learning is proposed for vehicle-to-vehicle (V2V) communications in VANETs. Firstly, a link maintenance time model is established, and the maintenance time is taken as an important parameter in the design of routing algorithm to ensure the reliability of each hop link. Aiming at the low efficiency and slow convergence of Q-learning, heuristic function and evaluation function are introduced to accelerate the update of Q-value of current optimal action, reduce unnecessary exploration, accelerate the convergence speed of Q-learning process and improve learning efficiency. The learning task is dispersed in each vehicle node in the new routing algorithm and it maintains the reliable routing path by periodically exchanging beacon information with surrounding nodes, guides the node’s forwarding action by combining the delay information between nodes to improve the efficiency of data forwarding. The performance of the algorithm is evaluated by NS2 simulator. The results show that the algorithm has a good effect on the package delivery rate and end-to-end delay

V2V Routing in VANET Based on Fuzzy Logic and Reinforcement Learning

To ensure the transmission quality of real-time communications on the road, the research of routing protocol is crucial to improve effectiveness of data transmission in Vehicular Ad Hoc Networks (VANETs). The existing work Q-Learning based routing algorithm, QLAODV, is studied and its problems, including slow convergence speed and low accuracy, are found. Hence, we propose a new routing algorithm FLHQRP by considering the characteristics of real-time communication in VANETs in the paper. The virtual grid is introduced to divide the vehicle network into clusters. The node’s centrality and mobility, and bandwidth efficiency are processed by the Fuzzy Logic system to select the most suitable cluster head (CH) with the stable communication links in the cluster. A new heuristic function is also proposed in FLHQRP algorithm. It takes cluster as the environment state of heuristic Q-learning, by considering the delay to guide the forwarding process of the CH. This can speed up the learning convergence, and reduce the impact of node density on the convergence speed and accuracy of Q-learning. The problem of QLAODV is solved in the proposed algorithm since the experimental results show that FLHQRP has many advantages on delivery rate, end-to-end delay, and average hops in different network scenarios