The reality of virtual worlds: pros and cons of their application to foreign language teaching

This article presents our experience of testing the OpenSim platform as a tool in teaching French to 108 tourism students at Universidad Rey Juan Carlos (Madrid, Spain). The article begins with some theoretical reflections on the behaviour of the student when using a virtual platform by means of an avatar, and with our observations of how this doubling of identity is actually the greatest asset of virtual worlds when we intend to apply them to teaching (1. Introduction). Then we move on to present our goals and method of work (2. Aims and methodology) and to analyse the development of the virtual space or sim, setting out the teaching strategies that were employed in each of the islands we created, and which correspond to reading comprehension, listening comprehension and written expression (3. Metaverse design). In order to assess the language learning results, we also devised tests throughout the experiment, which were repeated one month later. The assessment shows that the process of language acquisition is positive (4. Results analysis). Finally, we demonstrate that the rise of virtual worlds has been backed up by psycholinguistic factors, but at the same time their applicability and sustainability depend on technical aspects and very especially on theoretical and pedagogical tenets which are still to be drawn up (5. Conclusions).     

Testing Measurement Invariance Across Groups in Longitudinal Data: Multigroup Second-Order Latent Growth Model

In latent growth modeling, measurement invariance across groups has received little attention. Considering that a group difference is commonly of interest in social science, a Monte Carlo study explored the performance of multigroup second-order latent growth modeling (MSLGM) in testing measurement invariance. True positive and false positive rates in detecting noninvariance across groups in addition to bias estimates of major MSLGM parameters were investigated. Simulation results support the suitability of MSLGM for measurement invariance testing when either forward or iterative likelihood ratio procedure is applied.     

Constitutive model of saturated soft clay with cyclic loads under unconsolidated undrained condition

An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and extension tests were conducted to study the parameters of the model. Results showed that the relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain were nearly unique, when the initial octahedral shear stress ratios of specimens were equal to 0.3, 0.5 and 0.7. The relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain determined from the cyclic triaxial compression tests were basically the same as those determined from the cyclic triaxial extension tests. Furthermore, the relationships were not related to the initial stress condition, the test stress state and the octahedral cyclic shear stress ratio. The relationships determined from the cyclic triaxial tests under no deviatoric stress were basically the same as those determined from the cyclic triaxial tests under deviatoric stress. The change of the octahedral cyclic accumulative strain with the number of cycles was unique under different tests stress states. An equivalent visco-elastic constitutive model of saturated soft clay under UU condition was initially established.     

我国中小学生师比与平均班额解悖分析——从我国与部分OECD国家的比较角度

为解决我国中小学生师比与平均班额之间存在的"悖论",通过与部分OECD国家进行比较,发现我国教育经费投入严重不足、教师工作量过大、学生课业负担较重、教育规划布局不尽合理这四个方面,是导致我国中小学生师比与平均班额反常发展、班级规模居高不下的重要原因。     

变频调速技术在山区加压泵站的应用

文章通过实例说明了调速泵的节能效果,探讨了水泵调速运行的机理、调速范围及调速泵的最佳选择.     

关于武王伐纣之年的再研究

“慧星出而授殷入其柄”为武王伐封时重要天象，此慧星为布罗逊——梅特卡夫慧星，规模媲美哈慧。公元前1045年3月7日该星回归近日点，元前1045年1月5日牧野之战前后，黎明前出现于东方。“卜世三十，卜年七百”及“五星聚房”、“岁在鹑火”与姬昌称王、武王翦商的年代相符。王自称王始至周室东迁兼行二历制。     

Decay of softwood in archaeological wooden artifacts

Hardwoods and softwoods were used side by side throughout Egyptian history, and importing softwoods that had an attractive color and texture was common. Over the decades, artifacts based on hardwoods and softwoods underwent deterioration phenomena, sometimes reaching either a level of brittleness or turning into a wood powder that may easily crumble. These levels of decay/degradation are often difficult to handle in terms of conservation treatments. To study or identify the reasons for decay has always been a point of interest for conservation purposes, but to assess decay and choose an appropriate treatment according to the state of preservation for the sake of keeping an artifact intact has become a subject of major importance. It is difficult at times to understand the deterioration process, because hardwoods and softwoods are different in structure, properties, and chemical composition. For this preliminary study, decayed samples from three commonly used softwood types, cypress (Cupressus sp.), cedar (Cedrus sp.), and pine (Pinus sp.), were identified and chosen. Scanning electron microscopy (SEM) of the samples indicated the degree of decay. Decayed and non-aged samples of the same wood type were analyzed using Fourier transform infrared spectroscopy (FTIR), and all the major carbohydrate and lignin bands were recorded. The strong hydrogen bonded (O–H) stretching absorption associated with water linked by hydrogen bonds to the –OH groups of cellulose and hemicelluloses in all decayed samples increased with decay. The brown powdery, fragile samples that had been evidently affected by microbial decay had a higher amount of lignin. The lignin/carbohydrate ratio was calculated and results compared. The increase of either lignin percentage or extractives in some of the samples had caused a darkening of color in both cypress and cedar samples, but the pine sample did not have the same texture and appearance. In cases where the lignin percentage decreased the samples had changed to a slightly lighter color. FTIR results explained the decay phenomena observed in SEM micrographs and helped assess wood decay and also confirmed results that had been previously obtained while applying traditional chemical analysis on wood.     

Estimation of financial loss ratio for E-insurance: a quantitative model

In view of the risk of E-commerce and the response of the insurance industry to it, this paper is aimed at one important point of insurance, that is, estimation of financial loss ratio, which is one of the most difficult problems facing the E-insurance industry. This paper proposes a quantitative analyzing model for estimating E-insurance financial loss ratio. The model is based on gross income per enterprise and CSI/FBI computer crime and security survey. The analysis results presented are reasonable and valuable for both insurer and the insured and thus can be accepted by both of them. What we must point out is that according to our assumption, the financial loss ratio varied very little, 0.233% in 1999 and 0.236% in 2000 although there was much variation in the main data of the CSI/FBI survey.     

圆面积公式与圆周率究竟是怎样推求的

数学史上关于圆的度量和圆周率的推算，是中小学数学教学中十分有价值的史料，但对这一数学史实的认识有许多模糊的地方，运用与中学数学教学有关的例证澄清这一数学史实，给数学教学以重要启示：关于圆周率的教育价值应得到充分挖掘和客观体现。     

中国股市估值合理性研究

上交所统计数据表明,截至2007年12月28日,中国A股市场加权平均市盈率已达59.238倍,这一数字并非市场市盈率的真实反映,由于加权平均市盈率计算公式中对非流通股的不合理定价以及静态市盈率本身的局限,导致了计算出的市盈率结果系统性偏高。如果再考虑到当前的市盈率并没有包含对上市公司成长性的估计,那么A股市场的估值仍然是合理的。