An Approach to Gain Score Dependability & Validity for Criterion-Referenced Language Tests

Much of the recent work on criterion-referenced language testing addresses the issues of item writing and cut score dependability. Cdterion-referenced item writing is centrally concemed with determining the content congruence and leamability of each item's content. Cut score dependability focuses on the consistency of decisions in repeated testing or the assessment of language leamer performances. A more general issue related to language program development also involves empirical rationalization of cut score decisions. In this case the issue is of determining the optimal index of gain score dependability in the pre-instruction and post-instruction approach to assessing the language learning gains. The present paper examines a commonly used approach to assessing gain score dependability. Thc optimal index of gain score dependability is derived from examining the cut score dependability of the pre-instructional administration of the criterion-referenced test as well as the postinstructional criterion-referenced test, in relation to differences in the ratio of pre and post instruction variances. The database for the present paper comes from a preinstruction administration of an academic Iistening test followed by a counterbalanced post-instruction administration of an altemate form of the same test after one semester of instruction. The subjects were 213 advanced ESL learners at a large American university English language institute

Interface dynamics of table tennis

The purpose of this study was to discussed the Interface Dynamics of Table Tennis. The experiment was conducted based on the imaging principle of hot air flowing. We adopted the imaging principle of hot air flowing through rotating ball to simulate the flow phenomenon generated by air flowing through table tennis after striking by different rackets. The conclusion and suggestion after analyzing and discussing are described below: (1) The rotation of table tennis ball and flow field will change based on the roughness of rackets, which making its own contribution to the existence of changes in the rotation of table tennis ball. (2) It can learn that angle should forward 30 degrees with flat strike, 25 degrees with short particles and 20 degrees with long particles at the rotational speed of 7500 rpm. All flow fields of different rackets are similar

Chinese users’ preference for web browser icons

This paper compares the perspicacity, appropriateness and preference of web browser icons from leading software providers with those of a culture-specific design. The history and future direction of web browsers is outlined, together with the implications for the future growth of Chinese internet users. China, with its rapidly expanding young netizens has now overtaken the USA in terms of the number of internet users (253 million) and we predict it will reach saturation (?70% internet penetration rate) by 2012. If correct, this will have a dramatic effect on the use of English as the ‘Lingua Franca’ of the Internet. This online study was conducted in Taiwan and involved 103 participants (mean age 21 years), who were given three sets of web browser icons to review, namely Microsoft Internet Explorer 7.0, Macintosh Safari 3.0, and culturally specific icons created using the Culture-Centred Design methodology. The findings of the study show that all three sets have generally high recognition rates, but that some icon functions (e.g. Go/Visit and Favourite) in all three sets have poor recognition rates and are considered inappropriate. Furthermore, some significant differences were found when we analysed the level of user experience amongst several icon

Interface dynamics of table tennis

The purpose of this study was to discussed the Interface Dynamics of Table Tennis. The experiment was conducted based on the imaging principle of hot air flowing. We adopted the imaging principle of hot air flowing through rotating ball to simulate the flow phenomenon generated by air flowing through table tennis after striking by different rackets. The conclusion and suggestion after analyzing and discussing are described below: (1) The rotation of table tennis ball and flow field will change based on the roughness of rackets, which making its own contribution to the existence of changes in the rotation of table tennis ball. (2) It can learn that angle should forward 30 degrees with flat strike, 25 degrees with short particles and 20 degrees with long particles at the rotational speed of 7500 rpm. All flow fields of different rackets are similar

Two-Axis Solar Heat Collection Tracker System for Solar Thermal Applications

An experimental study was performed to investigate the effect of using a continuous operation two-axes tracking on the solar heat energy collected. This heat-collection sun tracking which LDR (light dependent resistor) sensors installed on the Fersnel lens was used to control the tracking path of the sun with programming method of control with a closed loop system. The control hardware was connected to a computer through Zigbee wireless module and it also can monitor the whole tracking process information on a computer screen. An experimental study was performed to investigate the effect of using two-axes tracking on the solar heat energy collected. The results indicate that sun tracking systems are being increasingly employed to enhance the efficiency of heat collection by polar-axis tracking of the sun. Besides, the heating power was also measured by designed power measurement module at the different focal length of Fresnel lens, and the design of shadow mask of LDR sensors is an important factor for solar photothermal applications. Moreover, the results also indicated that the best time to obtain the largest solar irradiation power is during 11:00 –13:00  in Taiwan

Exercise training with negative pressure ventilation improves exercise capacity in patients with severe restrictive lung disease: a prospective controlled study

BACKGROUND: Exercise training is of benefit for patients with restrictive lung disease. However, it tends to be intolerable for those with severe disease. We examined whether providing ventilatory assistance by using negative pressure ventilators (NPV) during exercise training is feasible for such patients and the effects of training. METHODS: 36 patients with restrictive lung disease were prospectively enrolled for a 12-week multidisciplinary rehabilitation program. During this program, half of them (n:18; 60.3 ± 11.6 years; 6 men; FVC: 32.5 ± 11.7% predicted ) received regular sessions of exercise training under NPV, whilst the 18 others (59.6 ± 12.3 years; 8 men; FVC: 37.7 ± 10.2% predicted) did not. Exercise capacity, pulmonary function, dyspnea and quality of life were measured. The primary endpoint was the between-group difference in change of 6 minute-walk distance (6MWD) after 12 weeks of rehabilitation. RESULTS: All patients in the NPV-exercise group were able to tolerate and completed the program. The between-group differences were significantly better in the NPV-exercise group in changes of 6MWD (34.1 ± 12.7 m vs. -32.5 ± 17.5 m; P = 0.011) and St George Score (−14.5 ± 3.6 vs. 11.8 ± 6.0; P < 0.01). There was an improvement in dyspnea sensation (Borg’s scale, from 1.4 ± 1.5 point to 0.8 ± 1.3 point, P = 0.049) and a small increase in FVC (from 0.85 ± 0.09 L to 0.91 ± 0.08 L, P = 0.029) in the NPV-exercise group compared to the control group. CONCLUSION: Exercise training with NPV support is feasible for patients with severe restrictive lung diseases, and improves exercise capacity and health-related quality of life

Structural properties of crumpled cream layers

The cream layer is a complex heterogeneous material of biological origin which forms spontaneously at the air-milk interface. Here, it is studied the crumpling of a single cream layer packing under its own weight at room temperature in three-dimensional space. The structure obtained in these circumstances has low volume fraction and anomalous fractal dimensions. Direct means and noninvasive NMR imaging technique are used to investigate the internal and external structure of these systems.Comment: 9 pages, 4 figures, accepted in J. Phys. D: Appl. Phy

Molecular Dynamics Simulations of the Roller Nanoimprint Process: Adhesion and Other Mechanical Characteristics

Molecular dynamics simulations using tight-binding many body potential are carried out to study the roller imprint process of a gold single crystal. The effect of the roller tooth’s taper angle, imprint depth, imprint temperature, and imprint direction on the imprint force, adhesion, stress distribution, and strain are investigated. A two-stage roller imprint process was obtained from an imprint force curve. The two-stage imprint process included the imprint forming with a rapid increase of imprint force and the unloading stage combined with the adhesion stage. The results show that the imprint force and adhesion rapidly increase with decreasing taper angle and increasing imprint depth. The magnitude of the maximum imprint force and the time at which this maximum occurs are proportional to the imprint depth, but independent of the taper angle. In a comparison of the imprint mechanisms with a vertical imprint case, while high stress and strain regions are concentrated below the mold for vertical imprint, they also occur around the mold in the case of roller imprint. The regions were only concentrated on the substrate atoms underneath the mold in vertical imprint. Plastic flow increased with increasing imprint temperature

Synthesis, formation and characterization of ZnTiO3 ceramics,Ceram

Abstract Zinc titanate (ZnTiO 3 ) powders of perovskite structure were synthesized by conventional solid state reaction using metal oxides. Powders of ZnO and TiO 2 in a molar ratio of 1:1 were mixed in a ball mill and then heated at temperatures from 700 to 1000 • C for various time periods in air. The crystallization temperature of ZnTiO 3 powder was ∼820 • C, activation energy for crystallization was ∼327.14 kJ/mol and for grain growth was ∼48.84 kJ/mol. A transition point was observed when the electrical resistivity was measured versus temperature. Like some ferroelectric materials, a PTCR behavior above the transition temperature was observed with Curie temperature of ∼5 • C