Left-handed materials in magnetized metallic magnetic thin films

INTRODUCTION Veselago (1968) showed that if both the permit- tivity ε and the magnetic permeability μ of a material are negative, the propagation direction of an elec- tromagnetic (EM) wave will be opposite to its energy flow direction. Such media are called left-handed materials (LHMs) since the electric field E, magnetic field H, and wave vector k in these media form a left-hand triplet of vectors, instead of a right-hand triplet observed in conventional materials. For a long time, …     

The assessment and prevention of answer copying on undergraduate multiple-choice examinations

Multiple-choice examination answer copying was indexed by a comparison of the numbers of items answered incorrectly, and in the same way, as adjacent and distant classmates. In Experiment I, which involved a regular university examination, significant copying did occur, did not differ from front to rear of the lecture hall, and appeared primarily among individuals seated next to one another. Copying was not related to the order in which the examinations were returned. Number correct was related to turn-in order in a U-shaped fashion. No significant copying appeared in a second experiment, where test performance did not contribute to course grade.     

University Choice: What Influences the Decisions of Academically Successful Post‐16 Students?

The questionnaire survey reported in this paper is part of an ongoing evaluation of the effect of a bursary scheme on recruitment to Cambridge University. It sought to identify factors that encouraged or discouraged highly successful A Level students from applying to Cambridge. Findings reveal three main dimensions associated with the decision to apply to Cambridge, the nature of the courses, the prestige of the university and anxiety about the application process combined with fear of failure. Further analyses showed that there were complex interactions between these three dimensions which governed the decision to apply to Cambridge. These findings are relevant to other prestigious universities. The availability of a bursary did appear to influence the decisions of those who were eligible, but its influence was not as great as some of the other factors.     

Comparison of computed tomography and chest radiography in the detection of rib fractures in abused infants

PURPOSE: Chest radiographs (CXR) are the standard method for evaluating rib fractures in abused infants. Computed tomography (CT) is a sensitive method to detect rib fractures. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants. METHODS: This retrospective study included all 12 abused infants identified from 1999 to 2004 who had rib fractures and both CXR and CT (8 abdomen CTs, 4 chest CTs). CT exams had been performed for clinical indications, and were obtained within one day of the CXR. Studies were reviewed by two pediatric radiologists to determine the number, locations, and approximate ages of the rib fractures. A total of 225 ribs were completely (192) or partially (33) seen by CT, and the matched ribs on CXR were used for the analysis. RESULTS: The mean patient age was 2.5 months (1.2-5.6), with seven females and five males. While 131 fractures were visualized by CT, only 79 were seen by CXR (p<.001). One patient had fractures only seen by CT. There were significantly (p<.05) more early subacute (24 vs. 4), subacute (47 vs. 26), and old fractures (4 vs. 0) seen by CT than by CXR. Anterior (42 vs. 11), anterolateral (21 vs. 12), posterolateral (9 vs. 3) and posterior (39 vs. 24) fractures were better seen by CT than by CXR (p<.01). Bilateral fractures were detected more often by CT (11) than by CXR (6). CONCLUSIONS: While this study group is small, these findings suggest that CT is better than CXR in visualizing rib fractures in abused infants.