Measurement of Nonplanar Dielectric Samples Using an Open Resonator

Conventional microwave methods for measuring permittivity often utilize samples in flat sheet form. In practice, however, it is sometimes desirable to measure samples having curved surfaces, for example, parts of lenses or small radomes. This paper describes an open resonator technique for achieving this and compares measurements made at 11.6 GHz on samples of polymethyl methacryIate in both curved and flat sheet form

LEXTALE_CH: A quick, character-based proficiency test for Mandarin Chinese

Research in second language acquisition suggests that objective performance-based assessments may provide more reliable and valid measures of second language proficiency than subjective self-ratings. To measure proficiency in English as a second language, a quick, vocabulary-based test called LexTALE (Lexical Test for Advanced Learners of English) was developed and shown to be able to differentiate between various levels of English proficiency. Following in the line of adaptations of this test for other languages, we created a character-based adaptation for Mandarin Chinese: LEXTALE_CH. In this paper, we discuss the development and validation of LEXTALE_CH in detail. In short, LEXTALE_CH can discriminate between high and low levels of Mandarin proficiency and is sensitive to the significant differences in vocabulary size between native speakers and second language learners of Mandarin; further, it takes only a few minutes to administer and is simple to score, making it a practical tool for low-stakes estimation of Mandarin proficiency.http://www.lingref.com/bucld/42/BUCLD42-09.pdfPublished versio

Coexistence for a multitype contact process with seasons

We introduce a multitype contact process with temporal heterogeneity involving two species competing for space on the $d$-dimensional integer lattice. Time is divided into seasons called alternately season 1 and season 2. We prove that there is an open set of the parameters for which both species can coexist when their dispersal range is large enough. Numerical simulations also suggest that three species can coexist in the presence of two seasons. This contrasts with the long-term behavior of the time-homogeneous multitype contact process for which the species with the higher birth rate outcompetes the other species when the death rates are equal.Comment: Published in at http://dx.doi.org/10.1214/09-AAP599 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org