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关键词： Living polymerization  

摘要： Synthesis of functionalized sequence-controlled polymers by utilizing 1,1-diphenylethylene (DPE) derivatives in living anionic polymerization is an effective method. Considering the capacity of sequence information and the diversity of functionalization, further progress of this method may provide a deep understanding of the copolymerization behavior of various DPE derivatives with commercial monomers. In this paper, we introduced two categories of DPE derivatives in anionic polymerization to enrich a variety of sequence-controlled polymers. The kinetics and monomer sequences of the terpolymerizations of St with two DPE derivatives through a one-step and multi-step feeding process were carefully studied. The results show that the terpolymer sequence displayed intriguing transformations by precisely controlling the reactivity difference between DPE derivatives, and facilely regulating the feed strategies of monomer pairs. The gradient, block and random distributions of two categories of DPE derivative units in the chain can be easily generated. The diversity ofT(g)values of these terpolymers with similar chemical compositions could prove that the various sequences have distinct effects on polymer properties.

关键词： Grothendieck bifibrations   Model categories   Reedy categories  

摘要： In this article, we develop a notion of Quillen bifibration whose purpose is to combine the two notions of Grothendieck bifibration and of Quillen model structure. In particular, given a bifibration p : E -> B, we describe when a family of model structures on the fibers E-A and on the basis category B combines into a model structure on the total category E, such that the functor p preserves cofibrations, fibrations and weak equivalences. Using this Grothendieck construction for model structures, we revisit the traditional definition of Reedy model structures, and possible generalizations, and exhibit their bifibrational nature. (C) 2020 Elsevier Inc. All rights reserved.

关键词： Neck pain   Mild traumatic brain injury   Outcome   Posttraumatic complaints  

摘要： Background Acute neck pain (ANP) has recently been demonstrated to be a predictor of persistent posttraumatic complaints after mild traumatic brain injury (mTBI). The aim of this study was to determine specific characteristics of patients with ANP following mTBI, their posttraumatic complaints and relationship with functional outcome. Methods Data from a prospective follow-up study of 922 mTBI patients admitted to the emergency department (ED) in three level-one trauma centres were analysed. Patients were divided into two groups: 156 ANP patients and 766 no acute neck pain (nANP) patients. Posttraumatic complaints were evaluated 2 weeks and 6 months post-injury using standardized questionnaires and functional outcome was evaluated at 6 months with the Glasgow Outcome Scale Extended (GOSE). Results ANP patients were more often female (p < 0.01), younger (38 vs. 47 years,p < 0.01) with more associated acute symptoms at the ED (p < 0.05) compared to nANP patients. More motor vehicle accidents (12% vs. 6%,p = 0.01) and less head wounds (58% vs. 73%,p < 0.01) in ANP patients indicated 'high-energy low-impact' trauma mechanisms. ANP patients showed more posttraumatic complaints 2 weeks and 6 months post-injury (p < 0.05) and more often incomplete recovery (GOSE < 8) was present after 6 months (56% vs. 40%,p = 0.01). Conclusions MTBI patients with acute neck pain at the ED constitute a distinct group within the mTBI spectrum with specific injury and demographic characteristics. Early identification of this at risk group already at the ED might allow specific and timely treatment to avoid development of incomplete recovery.

关键词： Packaging   Food waste   Packaging function   Service   Household   Behaviour  

摘要： Food wastage in households remains a sustainability challenge that poses both environmental and social problems. Among the many factors contributing to this problem, the packaging, including its design and functions, can either leverage or reduce food waste. Yet packaging is often considered an environmental villain, which can lead to missed opportunities for reducing food waste. Against this background, this study explored and quantified the packaging-food waste relationship in households. To explore this relationship, a multi-step method was applied to grasp the role of packaging in consumers' everyday practices and routines. The method incorporated a questionnaire, food waste diary and in-depth interview to measure food waste across different food categories and explore the underlying reasons for food wastage. According to an analysis of 37 households, packaging played a significant role especially in bread, dairy, meat and staple food wastage. For countering this problem, the most important factors related to packaging are its size and display of detailed information about product safety and storage. This study's theoretical contribution lies in offering a service lens and an 'outside-in' approach for exploring the consumer's value creation process and providing a context for better understanding why food wastage occurs in households. For policymakers and packaging designers, this study provides new insights into the relationship between consumer food practices and packaging, thus informing future food waste reduction initiatives. (C) 2020 The Authors. Published by Elsevier Ltd.

关键词： Categorical entropy   Abelian surfaces  

摘要： In this note, we shall compute the categorical entropy of an autoequivalence on a generic abelian surface. (C) 2020 Published by Elsevier Inc.

关键词： Dimensions   Bounded derived categories   Upper bounds   Projective dimension   Injective dimension   Radical layer length  

摘要： Let Lambda be an artin algebra. We give an upper bound for the dimension of the bounded derived category of the category mod Lambda of finitely generated right Lambda-modules in terms of the projective and injective dimensions of certain class of simple right Lambda-modules as well as the radical layer length of Lambda. In addition, we give an upper bound for the dimension of the singularity category of mod Lambda in terms of the radical layer length of Lambda. (C) 2020 Elsevier Inc. All rights reserved.

关键词： Machine learning   Co-clustering   Nonnegative matrix factorization   Category consistency   Neighbor constraint   Dual regularization  

摘要： Clustering has long been an enduring and promising task in machine learning. However, developed one-side clustering is still insufficient to explore the context of data, such as texts and genes. Hence, developing two-way clustering has drawn more attention in recent years, which tends to cluster samples and features simultaneously. This paper proposes a sparse neighbor constrained co-clustering via category consistency learning, for alleviating the misclassification of close points. Following an additional observation, samples often fall into the same category as their neighbors, as do features. Accordingly, the co-clustering problem is formulated as nonnegative matrix tri-factorization appended dual regularizers, considering coherence between data affinity and label assignment. Then, a multiplicative alternating scheme is raised for objective optimization, whose convergence and correctness are theoretically guaranteed. Furthermore, the proposed approach is validated on six datasets using three evaluation metrics, whose parameter sensitivity is analyzed as well. Finally, comprehensive experiments show that our algorithm is competitive against existing ones. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Categorical perception   Neuromodulation   Anterior temporal lobe   Color perception  

摘要： The linguistic category-advantage in color perception refers to better discrimination performance for stimuli that belong to different categories (e.g., green vs. blue) than equidistant stimuli from the same category (e.g., blue). Despite the robust nature of category-advantage in color perception, the related cognitive and neural mechanisms are not fully understood. Some views attribute this effect to early alteration of visual processing of color while others attribute it to post-perceptual conceptual processing. The current study investigated the causal role of the left anterior temporal lobe (ATL), as a post-perceptual semantic hub, in categorical color perception. We modulated the activity of the left ATL via cathodal tDCS or sham stimulation (within-subject) while participants were discriminating between successive presentations of color patches. Without stimulation, we found a category-advantage effect in both accuracy and response times. The inhibition of left ATL eliminated the category-advantage effect in terms of RTs but not accuracies. Our results point at the causal role of ATL in categorical color perception and provide indirect support for a post-perceptual processing account of this robust phenomenon.

关键词： Disaster   Community   Social justice   Critical theory   Disaster politics   Environmental justice  

摘要： Purpose - The authors engage a set of critical discussions on key concepts in disaster studies with attention to recent critiques of the concept "community," which decry the term's imprecision and problematic insinuation of consensus. The authors' objective is to explore for enduring and redeeming merit in the use of the term in disaster prevention, response and recovery and in collaborative social science research more broadly. Design/methodology/approach - This paper is based on case studies drawn from the authors' ongoing, longitudinal studies of community-based work with Spanish-speaking community leaders in San Jose, California and rural Indigenous communities in Alaska. Findings - The authors synthesize unromantic critiques of the community concept that surface important matters of inequality that complicate efforts for decolonizing disaster work with a view of community as an often utopian project servicing redistributions and relocations of the loci of power. It is a term not only invoked in scholarship and the work of governmental and nongovernmental agencies but also one with deeply symbolic and contextualized meaning. Originality/value - The authors' interpretation is that we must at once be critical and unromantic in studying and working with "community" while also recognizing its utopian fecundity. Abandoning the concept altogether would not only create a massive lacuna in everyday speech but also we fear too strong a language in opposition to the community concept metaphor telegraphs a hostility toward those who use it to mobilize scarce social, political and material resources to confront power and contest structural violence.

摘要： The article focuses on the significant ethical differences which imputed to the existing somatic/germline distinction indicate the technical categories which play an important role in debates on gene editing. It mentions that create finer and finer degrees of distinction between technical categories does not axiomatically identify ethical distinctions.