and u is the total variation (or just variation) of σ. For example, the total variation of the word σ = 1121415221 ∈ [5] is u(σ) = 0 + 1 + 1 + 3 + 3 + 4 + 3 + 0 + 1 = 16. Several authors have studied the statistic u(σ) in different contexts. For example, Curtis [5] discussed the problem of finding a word σ = σ1σ2 · · ·σn over the alphabet {a1, a2, . . . , ak} which maximizes the risk function ∑...

The cover image is based on the Research Article A new deuterium-labeled compound [2,3,4,6,6’-2H5]-D-glucose for deuterium magnetic resonance metabolic imaging by Chao Zou et al., https://doi.org/10.1002/nbm.4890.

Alexandre Baron,1,2 Thang B. Hoang,1,3 Chao Fang,1,2 Maiken H. Mikkelsen,1,2,3 and David R. Smith1,2,3 1Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, North Carolina 27708, USA 2Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA 3Department of Physics, Duke University, Durham, North Carolina 27708, USA (Received 10...

In article number 2200199, Chao Zhao and co-workers report emulsion-induced polymersomes. Through a simple emulsification process, the polymer forms polymersomes within seconds, formed effectively encapsulate water-soluble drugs in them.

Although the literature on flipped instruction to date appears to be relatively atheoretical, the benefits listed in the flipped literature fit well with theories of optimal learning environments (e.g., Egbert, Hanson-Smith, & Chao, 2007) and student engagement (Lin, 2012, and others). This conceptual paper links flipped instruction to these two models and then briefly describes an ESL teacher ...

Chao Li, Daniel E. Holz, and Asantha Cooray California Institute of Technology, Mail Code 130-33, Pasadena, California 91125, USA Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA, and Department of Astronomy & Astrophysics, University of Chicago, Chicago, Illinois 60637, USA The Observatories of the Carnegie Institution of Washington, Pasadena, California ...

Guanxiao Cheng1,2,3, Yong Yang4, Chao Hu2,3,5, Ping Xu1, Helun Song6, Tingwen Xing4 and Max Q.-H. Meng2,3 1College of Electronic Science and Technology, Shenzhen University, Shenzhen, 2Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 3The Chinese University of Hong Kong, Hong Kong, 4Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, 5Nin...

In this paper, we study how to partition a tree into edge-disjoint subtrees of approximately the same size. Given a tree T with n edges and a positive integer k ≤ n, we design an algorithm to partition T into k edge-disjoint subtrees such that the ratio of the maximum number to theminimum number of edges of the subtrees is at most two. The best previous upper bound of the ratio is three, given ...