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931.
Performance data are usually collected in order to build well‐defined performance indicators. Since such data may conceal additional information, which can be revealed by secondary analysis, we believe that mining of performance data may be fruitful. We also note that performance databases usually contain both qualitative and quantitative variables for which it may be inappropriate to assume some specific (multivariate) underlying distribution. Thus, a suitable technique to deal with these issues should be adopted. In this work, we consider nonlinear principal component analysis (PCA) with optimal scaling, a method developed to incorporate all types of variables, and to discover and handle nonlinear relationships. The reader is offered a case study in which a student opinion database is mined. Though generally gathered to provide evidence of teaching ability, they are exploited here to provide a more general performance evaluation tool for those in charge of managing universities. We show how nonlinear PCA with optimal scaling applied to student opinion data enables users to point out some strengths and weaknesses of educational programs and services within a university. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
932.
张荣娥 《宁波大学学报(理工版)》2007,20(3):346-349
研究了范畴C中有满单分解态射ψ关于态射h,k的加权Moore-Penrose逆ψ hk的存在性问题,给出了ψ hk存在的几个充分必要条件,推广了态射的Moore-Penrose逆的相应结果.其次,讨论了态射乘积的加权Moore-Penrose逆,得到了乘积公式成立的一个充要务件. 相似文献
933.
文章研究了三角范畴D及其coherent函子范畴A(D)的recollement之间的关系.利用D的recollement可以诱导A(D)的prerecollement,文章证明了该prerecollement是recollement的充分必要条件是D的recollement是可裂的;并且D的recollement可以诱导A(D)的prerecollement. 相似文献
934.
Plinio Alejandro Trinidad-Caldern Laura Margarita Lpez-Castillo Salvador Gallegos-Martínez Grissel Trujillo-de Santiago Silverio García-Lara Mario Moiss lvarez 《Molecules (Basel, Switzerland)》2022,27(9)
The development of novel cancer therapeutic strategies has garnered increasing interest in cancer research. Among the therapeutic choices, chemosensitizers have shown exciting prospects. Peptides are an attractive alternative among the molecules that may be used as chemosensitizers. We rationally designed a new-to-nature peptide, nurP28, derived from the 22-kDa α-zein protein sequence (entry Q00919_MAIZE). The resultant sequence of the nurP28 peptide after the addition of arginine residues was LALLALLRLRRRATTAFIIP, and we added acetyl and amide groups at the N- and C-terminus, respectively, for capping. We evaluated the cytotoxicity of the nurP28 peptide alone and in combination with docetaxel in fibroblast monolayers and breast cancer monolayers and spheroids. Our results indicated that nurP28 is not cytotoxic to human fibroblasts or cancer cells. Nevertheless, when combined with 1 µM docetaxel, 3 ng/mL nurP28 induced equivalent (in MCF7 monolayers) and higher (in MCF7 spheroids) cytotoxic effects than 10-fold higher doses of docetaxel alone. These findings suggest that nurP28 may act as a chemosensitizer in breast cancer treatment. This study describes the enhancing “anti-cancer” effects of nurP28 in breast cancer 2D and 3D cultures treated with docetaxel. Further studies should explore the mechanisms underlying these effects and assess the clinical potential of our findings using animal models. 相似文献
935.
936.
937.
本文论述了受迫振动方程建立与求解,相关物理量的理论推导,并附以测量实例进行分析,解决了同学们该实验疑难之处,补充了教材之空缺。 相似文献
938.
《Expositiones Mathematicae》2019,37(1):2-24
We give a complete and careful proof of Quillen’s theorem on the existence of the standard model category structure on the category of topological spaces. We do not assume any familiarity with model categories. 相似文献
939.
对于任意给定的性质${\mathcal{P}}$和序列$\rho$, 词上的组合领域一个重要的研究课题是找出所有的因子$\omega$和序数$p$,使得序列$\rho$中第$p$次出现的因子$\omega$ (记为$\omega_p$) 满足性质${\mathcal{P}}$.这个问题等价于研究``因子谱''.确定因子谱是一个困难的问题. 为了实现目标,我们引入并研究了一系列的概念:核词、包络词、回归词和任意因子的诱导序列. 利用因子谱和诱导序列,我们可以解决序列中的一些计数问题.例如:在序列的任意一个片段中回文或者高次方词的个数. 本文中,我们将结合几个特殊的序列展示相关的研究结果.这些序列包括: Fibonacci序列、Tribonacci序列、Period-doubling序列等等. 我们相信这些概念和方法对于所有的一致常返序列都是有效的. 相似文献
940.
Yuan Zhang Wen‐jie Wu Wei‐e Zhou Zhi‐qin Ren Xue‐song Feng Feng Zhang 《Journal of separation science》2020,43(7):1372-1381
A novel, simple, and sensitive method has been developed for simultaneous determination of 14 heterocyclic aromatic amines in meat product using solid‐phase extraction combined with ultrahigh‐performance supercritical fluid chromatography coupled to tandem quadrupole mass spectrometry. The analytes could be separated within 7 min and identified using their retention times and mass. The developed method was validated based on the linearity, limits of quantification, precision, and accuracy. The recovery ranged from 52.3 to 97.5% with an acceptable standard deviation, which is not higher than 6%. The limits of quantitation ranged from 0.03 to 0.17 µg/kg. The selectivity and sensitivity were satisfactory in multiple reaction monitoring mode. The method was applied to commercial meat products, and the results demonstrated that the novel method has potential for the analysis of the targets in food matrices. This is the first work reporting the simultaneous quantification of 14 heterocyclic aromatic amines by means of ultrahigh‐performance supercritical fluid chromatography coupled to tandem quadrupole mass spectrometry. 相似文献