The estimation of the IRT reliability coefficient and its lower and upper bounds, with comparisons to CTT reliability statistics

The primary purpose of this study is to investigate the mathematical characteristics of the test reliability coefficient ρ _XX′ as a function of item response theory (IRT) parameters and present the lower and upper bounds of the coefficient. Another purpose is to examine relative performances of the IRT reliability statistics and two classical test theory (CTT) reliability statistics (Cronbach’s alpha and Feldt–Gilmer congeneric coefficients) under various testing conditions that result from manipulating large-scale real data. For the first purpose, two alternative ways of exactly quantifying ρ _XX′ are compared in terms of computational efficiency and statistical usefulness. In addition, the lower and upper bounds for ρ _XX′ are presented in line with the assumptions of essential tau-equivalence and congeneric similarity, respectively. Empirical studies conducted for the second purpose showed across all testing conditions that (1) the IRT reliability coefficient was higher than the CTT reliability statistics; (2) the IRT reliability coefficient was closer to the Feldt–Gilmer coefficient than to the Cronbach’s alpha coefficient; and (3) the alpha coefficient was close to the lower bound of IRT reliability. Some advantages of the IRT approach to estimating test-score reliability over the CTT approaches are discussed in the end.     

具有转向点的非线性系统的奇异摄动

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A simple method for chiral resolution of 1,1′-Bl-2-naphthol

An improved method for preparing enantiomerically pure 1,1′-bi-2-naphthols is described. 1,1′-bi-2-naphthol boric anhydride was generated from the reaction of racemic 1,1′-bi-2-naphthol and boric anhydride. Its two diastereoisomers, could be efficiently separated in THF using (L)-proline as the resolving agent. Treatment in three successive steps yielded 79% and 74% enantiomerically pure (S)-and (R)-1,1′-bi-2-naphthol respectively.     

On Turán type inequality with doubling weights andA * weights

LetH _n be the set of real algebraic polynomials of degreen, whose zeros all lie in the interval [−1,1]. The well known Turán type inequalities tell us that forf(x)∈H _n , it holds ‖f′‖≥C√n‖f‖. This note deals with the weighted Turán type inequalities with the weights having inner singularities underL ^p norm for 0<p≤∞. Our results essentially extend the result of Wang and Zhou (2002), and the method used in this paper is simpler and more direct than that of Wang and Zhou (2002). The results and methods have their own values in approximation theory and computation.     

Regular-singular crossings on nonlinear systems with turning point

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Statistical estimates of learners�� judgments about knowledge in calibration of achievement

In theoretical models of self-regulated learning, calibration is one important component in successful learning. Two issues of calibration are explored. First, Nelson (1987) suggested the G (gamma) coefficient is the most appropriate measure of calibration (judgment accuracy) and rejected signal detection theory’s d′ statistic because data commonly challenge distributional assumptions. We empirically examined this issue, comparing G and d′. Second, we examined whether a learner’s calibration varies across three domains of knowledge: general, word, and mathematics. A sample of 266 university students volunteered to participate in the study. Participants were selected from various undergraduate and graduate courses. Participants first answered demographic items. Then they completed three knowledge tests (general, word, and mathematics) and judged correctness for each answer provided. Order of domains was randomly counterbalanced among participants. Results show that d′ is a valid measure of calibration, that assumptions about underlying distributions can be tested, and that preliminary evidence suggests that d′ may be a superior measure of accuracy compared to G. Finally, calibration varied by domain.     

A novel long-chain acyl-derivative of epigallocatechin-3-O-gallate prepared and purified from green tea polyphenols

Lipophilic tea polyphenols (LTP) were prepared by catalytic esterification of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-chain acyl-derivative of epigallocatechin-3-o-gallate (EGCG) was first isolated from purification of LTP by high-speed countercurrent chromatography (HSCCC) using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1∶1∶1∶1, v/v). The molecular structure of the acyl-derivative, Epigallocatechin-3-O-gallate-4′-O-hexadecanate, was elucidated by means of elemental analysis, IR,¹H-NMR and MS spectra. Project (No. 200010) supported by Zhejiang Provincial Natural Science Foundation, China     

Fiber optic biosensor of immobilized firefly luciferase

Luciferase from firefly lantern extract was immobilized on CNBr-activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. TheK _m′ for D-luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose-bound enzyme were 7.8 and 25°C respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10⁻⁹–10⁻⁵ mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.     

Splicing-site recognition of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) DNA sequences by support vector machines

Motivation: It was found that high accuracy splicing-site recognition of rice (Oryza sativa L.) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results: The prediction accuracy we obtained was 87.53% at the true 5′ end splicing site and 87.37% at the true 3′ end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches. Project partially supported by the Start-up Funding of Zhejiang University to Chen Liang-biao     

A study of the relationship between expression level of TRF1 protein and telomerase activity in human acute leukemia

INTRODUCTION Telomeres are distinctive DNA-protein struc-tures that cap the ends of linear chromosomes.It is very important to keep the chromosomes stabilization.Telomerase activity is closely linked to attainment of cellular immortality,a step in carcinogenesis,while lack of such activity contributes to cellular senes-cence.Telomerase is activated in more than85%ofmalignant tumors(Hiayma et al.,1997).Human te-lomeric repeat binding factor1(TRF1)is a telomere associated with proteins a…     

Analysis of the 3′ ends of tRNA as the cause of insertion sites of foreign DNA in Prochlorococcus

The purpose of this study was to investigate the characteristics of transfer RNA (tRNA) responsible for the association between tRNA genes and genes of apparently foreign origin (genomic islands) in five high-light adapted Prochlorococcus strains. Both bidirectional best BLASTP (basic local alignment search tool for proteins) search and the conservation of gene order against each other were utilized to identify genomic islands, and 7 genomic islands were found to be immediately adjacent to tRNAs in Prochlorococcus marinus AS9601, 11 in P. marinus MIT9515, 8 in P. marinus MED4, 6 in P. marinus MIT9301, and 6 in P. marinus MIT9312. Monte Carlo simulation showed that tRNA genes are hotspots for the integration of genomic islands in Prochlorococcus strains. The tRNA genes associated with genomic islands showed the following characteristics: (1) the association was biased towards a specific subset of all iso-accepting tRNA genes; (2) the codon usages of genes within genomic islands appear to be unrelated to the codons recognized by associated tRNAs; and, (3) the majority of the 3′ ends of associated tRNAs lack CCA ends. These findings contradict previous hypotheses concerning the molecular basis for the frequent use of tRNA as the insertion site for foreign genetic materials. The analysis of a genomic island associated with a tRNA-Asn gene in P. marinus MIT9301 suggests that foreign genetic material is inserted into the host genomes by means of site-specific recombination, with the 3′ end of the tRNA as the target, and during the process, a direct repeat of the 3′ end sequence of a boundary tRNA (namely, a scar from the process of insertion) is formed elsewhere in the genomic island. Through the analysis of the sequences of these targets, it can be concluded that a region characterized by both high GC content and a palindromic structure is the preferred insertion site.     

Odd behaviour of the even integer 2

It is always of interest when one finds a property that is true only of some given object, or some given class of objects. For example, if n > 1 is an integer, then (n − 1)! + 1 is divisible by n just when n is a prime number. In this article we look at some properties that are true only for the integer 2. Shailesh Shirali has been at Rishi Valley School, Andhra Pradesh (Krishnamurti Foundation India) since the 1980’s. He has a deep interest in teaching and writing about mathematics at the high school/post school levels, with particular emphasis on problem solving and on historical aspects of the subject. He has been involved in the Mathematics Olympiad movement at the national and international level for the past two decades. He is the author of several expository books and articles aimed at interested high school students.     

教育对不同群体收入的影响

This study investigates, statistically and econometrically, the income level, income inequality, education inequality, and the relationship between education and income of different social groups, on the basis of the Chinese Urban Household Survey conducted in 2005, the Gini coefficient and the quartile regression method. Research findings indicate that income inequality in China shows a significantly increasing trend since the beginning of the 1990s, which is attributed to the lowest income groups. Additionally, it is seen that the higher the level of education in a group, the smaller the income gap within it. As a result, the rate of returns on education for the “group with weaker ability to earn” is higher than that for the “group with stronger ability to earn”. Translated from Beijing Daxue Jiaoyu Pinglun 北京大学教育评论 (Peking University Education Review), 2006, 4(2): 85–92     

大学收费管制的目标

Regulation refers to governmental restrictions over enterprise in order to protect public interest. Research on governmental regulation in China primarily focuses on public utility, and inadequate attention has been paid to regulating college tuition. Currently, although the educational administrative agencies have successfully kept college tuition at the level of the year 2000, the governmental regulation on tuition has not achieved the effects expected because it has not been able to lower college tuition to the level that the public is willing to accept, and it has not established any internal scientific management system in colleges. The ultimate goal of college regulation should be establishing a healthy order among various social groups. After tuition is capped, the priority for constructing a scientific college management system is to define the goals for governmental regulation on college tuition. A feasible option for now is to replace cost analysis with intervention institutions and to improve the situation of asymmetric information. Translated by FENG Xiaojie from Gaodeng Jiaoyu Yanjiu 高等教育研究 (Journal of Higher Education), 2007, 28(8): 33–38     

Effect of mineral admixtures and repeated loading on chloride migration through concrete

The effect of fly ash (FA) and ground granulated blast furnace slag (GGBFS) on chloride migration through concrete subjected to repeated loading was examined. Portland cement was replaced by three percentages (20%, 30%, and 40%) of mineral admixtures. Five repeated loadings were applied to concrete specimens using a WHY series fully automatic testing machine. The maximum loadings were 40% and 80% of the axial cylinder compressive strength (f′c). Chloride migration through concretes was evaluated using the rapid chloride migration test and the chloride concentration in the anode chamber was measured. The results showed that the replacement percentages of mineral admixtures, the curing time and repeated loading had a significant effect on chloride migration through concrete. The transport number of chloride through concrete cured for 28 d increased with increasing FA replacement and markedly decreased with extension of the curing time. 20% and 30% GGBFS replacement decreased the transport number of chloride through concrete, but 40% GGBFS replacement increased the transport number. Five repeated loadings at 40% or 80% f′c increased the transport number of chloride for all mixes.     

Synthesis of Schiff bases of naphtha[1,2-d]thiazol-2-amine and metal complexes of 2-（2＇-hydroxy）benzylideneaminonaphthothiazole as potential antimicrobial agents

Objective： A series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes. Methods： Schiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-（2＇-Hydroxy）ben- zylideneaminonaphthothiazole was converted to its Co（Ⅱ）, Ni（Ⅱ） and Cu（Ⅱ） metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method. Results： All the compounds moderately inhibited the growth of Cram positive and Gram negative bacteria. In the present study among all Schiff bases 2-（2＇-hydroxy）benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu（Ⅱ） metal complex was found to be most potent. Conclusion： The results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases.     

Managing differentiation of higher education system in Japan: connecting excellence and diversity

This article presents recent reform processes in Japanese higher education, concerning the tensions emerging within the system regarding ‘excellence’ and ‘diversity’. The article particularly focuses on how Japanese universities have reacted to the recent ‘competition’ and ‘differentiation’ policy promoted by the government, drawing on recent survey results conducted with academic managers at Japanese universities. It is interesting to examine the case of Japan, a historically diversified and differentiated national system, which has been changing rapidly with recent national ‘top-down’ policy reforms, followed by more recent and new bottom-up institutional initiatives. The study shows that universities are trying to achieve excellence, fulfilling different functions at the same time, aspiring to be excellent in teaching, research and social contribution without having institutional capacity to meet these expectations. Appropriate internal governance and external mediation mechanisms need to be created at the institutional level to manage diversification of the higher education system as a whole.     

“It’s the X and Y Thing”: Cross-sectional and Longitudinal Changes in Children’s Understanding of Genes

Studies from different theoretical traditions investigating children’s inheritance and genetics concepts have adopted a cross-sectional method. This paper is the first to examine both cross-sectional and longitudinal changes in children’s basic genetic concepts. It forms part of a larger investigation into the development of intuitive inheritance and genetics concepts in childhood. Four age cohorts (4–5 years, 7–8 years, 10–11 years, 14–15 years) were interviewed individually at two measurement occasions (T1, N = 182; T2, N = 164) separated by a 1-year interval. Cross-sectional analyses revealed an increase in children’s knowledge of genetics by 10 years. Between 10 and 14 years, there were fewer changes in the content of children’s knowledge, especially at the level of scientific genetic understanding. There was little evidence of longitudinal changes over the 1-year period. Overall, children may hold an understanding of genetics that is tied to knowledge of inheritance within families. This may pose challenges for acquiring more abstract and formal concepts of genes.     

教师使用教科书的过程分析与水平测定

Teachers and textbooks are two important elements in curriculum implementation. Based on Concerns-Based Adoption Model (CBAM), a curriculum implementation measurement model designed by G. Hall and S. M. Hord, this paper analyzes the general process of curriculum implementation in terms of textbook use, establishes a model that gauges the level of textbook use and thus improves TC component check list designed by S. M. Hord. By studying five primary school math teachers, this paper measures their level of textbook use and makes a relevant comparative analysis. The result shows that the level of textbook use model is valid and accurate, and could therefore help improve teacher’s skill of textbook use and their professional development. Translated by WU Shan from Shanghai Jiaoyu Keyan 上海教育科研 (Shanghai Research on Education), 2008, (3): 4–9