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关键词： e-Liquids   Electronic cigarettes   Flavors   Flavor compounds   Flavor ingredients   Gas chromatography - mass spectrometry  

摘要： Objectives: Electronic cigarette refill solutions (e-liquids) are available in various flavor descriptions that can be categorized as fruit, tobacco, and more. Flavors increase sensory appeal, thereby stimulating e-cigarette use, and flavoring ingredients can contribute to e-cigarette toxicity. We aim to inform toxicologists, sensory scientists, and regulators by determining flavoring compounds in e-liquids with various flavors, and compare results between flavor categories. Methods: Gas chromatography - mass spectrometry (GC-MS) was used to identify 79 flavorings in 320 e-liquids, classified in 15 flavor categories. Ten flavorings highly prevalent in e-liquids according to information from manufacturers were quantified. Flavoring prevalence was defined as the number of e-liquids with the flavoring as percentage of the total number of e-liquids. The method was validated in terms of specificity, linearity, repeatability, recovery, and sensitivity. Results: The mean number of flavorings per e-liquid was 6 +/- 4. Flavoring prevalence was highest for vanillin (creamy/vanilla flavor), ethyl butyrate (ethereal/fruity), and cis-3-hexenol (fresh/green). Based on similarities in flavoring prevalence, four clusters of categories were distinguished: (1) fruit, candy, alcohol, beverages;(2) dessert, coffee/tea, nuts, sweets;(3) menthol/mint;and (4) spices, tobacco, and unflavored. Categories from cluster 4 generally had less flavorings per e-liquid than fruit, candy, alcohol, beverages (cluster 1) and dessert (cluster 2) (p < 0.05). Flavoring concentrations varied between e-liquids within the categories. Conclusions: We evaluated flavoring compositions of 320 e-liquids using a simple GC-MS method. Flavoring prevalence was similar within four clusters of typically fresh/sweet, warm/sweet, fresh/cooling, and non-sweet flavor categories. To compare flavoring concentrations between individual flavor categories, additional research is needed. (C) 2020 The Author(s). Published by Els

关键词： The root mean square error of approximation   confidence interval   categorical data   weighted least squares  

摘要： RMSEA estimation given nonnormal continuous data is usually based on the mean-adjusted () or mean-variance-adjusted () chi-square statistic, but a plain application of these statistics has poor performance. Savalei and colleagues gave a better way (the BSL method) to infer RMSEA using or . However, the BSL method is applicable to continuous data only. For categorical data, currently RMSEA inference is still based on a plain application of or , but such practice is already problematic under continuous data. In this paper, we first show that it is more meaningful to define RMSEA under unweighted least squares (ULS) than under weighted least squares (WLS) or diagonally weighted least squares (DWLS). Then, we propose a correct point estimator and confidence interval for RMSEA given categorical data and ULS. Simulation results show our methods perform well while all the traditional methods break down.

关键词： 教育管理学   四大范畴   高校体育教学   管理创新  

摘要： 随着现代教学理念的不断推进,我国高校逐渐意识到自身传统教学的不足,逐渐加快了教学改革的步伐。在高校体育教学管理中,相关管理教师应意识到传统体育教学管理的弊端,及时调整自身的管理方案,提高高校体育教学的综合质量,重视体育教师综合素质的提高,提高教师的教学质量,创新教师的教学思维。各高校体育教师应不断进行学习,补充自身的体育教学知识,根据学生的实际学习需求不同,进行教学方案的调整,提升高校体育教学的总体水平。

关键词： Brauer category   Brauer algebra   Categorification  

摘要： We study representations of the locally unital and locally finite dimensional algebra B associated to the Brauer category B(delta(0)) with defining parameter delta(0) over an algebraically closed field K with characteristic p not equal 2. The Grothendieck group K-0(B-mod(Delta)) will be used to categorify the integrable highest weight sl(K)-module V (pi delta(0) - 1/2) with the fundamental weight pi delta(0) - 1/2 as its highest weight, where B-mod(Delta) is a subcategory of B-lfdmod in which each object has a finite Delta-flag, and sl(K) is either sl(infinity) or sl(p) depending on whether p = 0 or 2 inverted iota p. As g-modules, C circle times(Z) K-0(B-mod(Delta)) is isomorphic to V (pi delta(0) - 1/2), where g is a Lie subalgebra of sl(K) (see Definition 4.2). When p = 0, standard B-modules and projective covers of simple B-modules correspond to monomial basis and so-called quasicanonical basis of V (pi delta(0) - 1/2), respectively. (C) 2020 Elsevier Inc. All rights reserved.

关键词： n-推出   加法范畴   幂等完备范畴  

摘要： n-推出作为经典推出概念的高维推广,是n-阿贝尔范畴结构理论中的重要研究对象.引入加法范畴的n-推出范畴的概念,进一步证明幂等完备范畴的n-推出范畴仍是幂等完备范畴.

关键词： 形-义关联度   敏感范畴   寄生范畴   弱关联   事态范畴  

摘要： 本文提出了"形-义关联度"的概念——语言形式和其意义的关系,按其强度大小分为强关联、中等关联和弱关联。寄生范畴和库藏手段之间属于弱关联,体现了语言形式和意义之间异常复杂的关系。文章全面深入考察了事态范畴在汉语各种范畴中的寄生情况,发现事态范畴广泛寄生于汉语的众多目标范畴中,体现了汉语母语者对其较高的敏感性,可被称为"隐性敏感范畴"。显赫范畴属于"显性敏感范畴"。

关键词： 预三角   三角范畴   八面体公理  

摘要： 在三角范畴中,与好三角同构的三角是好三角,对于预三角也得到了预三角在同构下是封闭的结论.三角范畴是一个带有自同构的加法范畴,并且满足4条公理,其中1条重要的公理是八面体公理,文章给出了三角范畴中八面体公理的几个等价刻画.

关键词： 准严格半Abel范畴   截断函子   伴随函子对  

摘要： 在准严格半Abel范畴的单边导出范畴上构造一类截断函子,并以此诱导出伴随函子对.

关键词： 教化范畴   古代诗学   儒家思想   当代  

摘要： “教化”是中国古代诗学的重要范畴,“文以明道”是其关于文艺本质的认识;“有裨风教”和提升个体的道德修养是其社会功能;“潜移默化”是其发挥作用的基本方式。“教化”在现代文艺学中也得到充分运用,梁启超的“新民”说、“五四”学人的“文学启蒙”、20年代的“文学革命”论、80年代“新启蒙”都与“教化”有密切关系。“教化”范畴贯穿古今的原因在于它已成为积淀于人们心理结构中的文化传统,其与以血缘宗法为根基的宗族社会和儒家教化思想都有密切关系。

关键词： 征求意见稿   特种作业   持证上岗制度   作业项目   危化品   意见反馈   操作项目   煤化工工艺  

摘要： 近日,应急管理部安全基础司就《特种作业目录(征求意见稿)》向社会公开征求意见,意见反馈截止时间为2020年9月6日。中国特种作业人员持证上岗制度于1954年建立,距今已有66年。现行特种作业目录于2010年印发,共10个作业类别、54个操作项目(含煤矿),实施近10年来,逐渐出现了一些不适应不符合的问题:一是随着工艺技术进步,一些作业不再存在重大安全风险;二是个别行业领域特种作业范围过宽,实施准入的人员数量过多,不符合"放管服"要求;三是实践中有些容易引发人员伤亡的作业项目没有纳入特种作业管理。