Re-imagining Education for Linguistically, Culturally, and Racially Diverse Students in a Changing Era: One U.S. School\u27s Alternative Vision

This dissertation sets out to describe, interpret, and understand how an urban K-8 charter school in Philadelphia that serves linguistically, culturally, and racially diverse students from low-income communities seeks to offer a type of education that recognizes its students\u27 minority status in the broader society and exceeds the education typically available for this group of students. In particular, this research asks how teachers circulate and enact their vision of creating an equitable education for all students and how middle school students\u27 identities are shaped by this vision. Drawing on the concepts of imagined communities in education, critical pedagogy, language ecology and Gee\u27s (2000) analytical perspectives on identities, the research explores innovative teaching and learning at this socially engaging urban school. Data from critical ethnography and critical discourse analysis indicate that curriculum has a strong focus on diversity, social justice, and students\u27 racialized experiences, which in turn have an impact on middle schoolers\u27 interracial/interethnic friendships. One unique educational alternative, Mandarin education, which offers students an opportunity to learn Mandarin either as a foreign language or heritage language before college, is highly contested among students for reasons related to the role of Mandarin in the local and broader language ecologies. Studying a school such as this one in its particular sociopolitical context and understanding how students navigate their school life become the basis for more grounded and informed discussions about how to create a more equitable education in contemporary educational contexts

Perovskite-Structured Photovoltaic Materials

In this chapter, we provide the historical background and overview of perovskite-structured photovoltaic materials. The organolead halide perovskite-structured solar cell is considered as one of the most promising photovoltaic technologies due to its rapid progress in power conversion efficiency. However, the existence of lead in perovskite-structured photovoltaic materials raises toxicological and environmental issues. Therefore, many scientists focused on discovering new materials that can replace the lead and improve photovoltaic performance. There are still some issues to be overcome before commercialization of perovskite-structured photovoltaic materials. The fast degradation phenomenon under humidity or constant irradiation is one such issue. The hysteresis phenomena could cause inaccurate estimation of power conversion efficiency. The choice of selective contact also plays an important role in obtaining high performance device. Therefore, the interaction between each layer should be considered. Overall, we reported on state-of-the-art perovskite-structured photovoltaic materials and discussed the essential factor for fabricating high-performance perovskite-structured solar cells

On 18\frac18-BPS black holes and the chiral algebra of N=4\mathcal{N}=4 SYM

We investigate the existence of $\frac18$-BPS black hole microstates in Type IIB string theory on $\mathrm{AdS}_5 \times \mathrm{S}^5$. As will be explained, these states are in one-to-one correspondence with the Schur operators comprising the chiral algebra of $\mathcal{N}=4$ super-Yang-Mills, and a conjecture of Beem et al. implies that the Schur sector only contains graviton operators and hence $\frac18$-BPS black holes do not exist. We scrutinize this conjecture from multiple angles. Concerning the macroscopic counting, we rigorously prove that the flavored Schur index cannot exhibit black hole entropy growth, and provide numerical evidence that the flavored MacDonald index also does not exhibit such growth. Next, we go beyond counting to examine the algebraic structure, beginning by presenting evidence for the well-definedness of the super-$\mathcal{W}$ algebra of Beem et al., then using modular differential equations to argue for an upper bound on the lightest non-graviton operator if existent, and finally performing a systematic construction of cohomologies to recover only gravitons. Along the way, we clarify key aspects of the 4d/2d correspondence using the formalism of the holomorphic topological twist.Comment: 36+15 pages, 5 figures, 6 table

Investors’ preference order of fuzzy numbers

AbstractNowadays greater and greater realistic financial problems are modeled by using the stochastic programming in the fuzzy environment. Hence, ranking a set of fuzzy numbers that is consistent with the investors’ preference becomes important for modelling a realistic problem. In this paper, we will provide a new ranking procedure that is consistent with the preference of the conservative investors. Our ranking procedure satisfies the axioms of three order relations for the separable fuzzy numbers or the triangle fuzzy numbers. We found that our ranking procedure has a better capability of discriminating the order of two fuzzy numbers. For the LR-type fuzzy numbers, our ranking procedure reduces the computational time substantially