3,910 research outputs found
Re-examining Phonological and Lexical Correlates of Second Language Comprehensibility:The Role of Rater Experience
Few researchers and teachers would disagree that some linguistic aspects
of second language (L2) speech are more crucial than others for successful
communication. Underlying this idea is the assumption that communicative
success can be broadly defined in terms of speakers’ ability to convey the
intended meaning to the interlocutor, which is frequently captured through
a listener-based rating of comprehensibility or ease of understanding (e.g.
Derwing & Munro, 2009; Levis, 2005). Previous research has shown that
communicative success – for example, as defined through comprehensible L2
speech – depends on several linguistic dimensions of L2 output, including its
segmental and suprasegmental pronunciation, fluency-based characteristics,
lexical and grammatical content, as well as discourse structure (e.g. Field,
2005; Hahn, 2004; Kang et al., 2010; Trofimovich & Isaacs, 2012). Our chief
objective in the current study was to explore the L2 comprehensibility construct from a language assessment perspective (e.g. Isaacs & Thomson, 2013),
by targeting rater experience as a possible source of variance influencing the
degree to which raters use various characteristics of speech in judging L2
comprehensibility. In keeping with this objective, we asked the following
question: What is the extent to which linguistic aspects of L2 speech contributing to comprehensibility ratings depend on raters’ experience
Nonlinear optics of fibre event horizons
The nonlinear interaction of light in an optical fibre can mimic the physics
at an event horizon. This analogue arises when a weak probe wave is unable to
pass through an intense soliton, despite propagating at a different velocity.
To date, these dynamics have been described in the time domain in terms of a
soliton-induced refractive index barrier that modifies the velocity of the
probe. Here, we complete the physical description of fibre-optic event horizons
by presenting a full frequency-domain description in terms of cascaded
four-wave mixing between discrete single-frequency fields, and experimentally
demonstrate signature frequency shifts using continuous wave lasers. Our
description is confirmed by the remarkable agreement with experiments performed
in the continuum limit, reached using ultrafast lasers. We anticipate that
clarifying the description of fibre event horizons will significantly impact on
the description of horizon dynamics and soliton interactions in photonics and
other systems.Comment: 7 pages, 5 figure
Widely tunable optical parametric oscillation in a Kerr microresonator
We report on the first experimental demonstration of widely-tunable
parametric sideband generation in a Kerr microresonator. Specifically, by
pumping a silica microsphere in the normal dispersion regime, we achieve the
generation of phase-matched four-wave mixing sidebands at large frequency
detunings from the pump. Thanks to the role of higher-order dispersion in
enabling phase matching, small variations of the pump wavelength translate into
very large and controllable changes in the wavelengths of the generated
sidebands: we experimentally demonstrate over 720 nm of tunability using a
low-power continuous-wave pump laser in the C-band. We also derive simple
theoretical predictions for the phase-matched sideband frequencies, and discuss
the predictions in light of the discrete cavity resonance frequencies. Our
experimentally measured sideband wavelengths are in very good agreement with
theoretical predictions obtained from our simple phase matching analysis.Comment: 5 pages, 4 figure
APPLYING MULTIPLE IMPUTATION FOR EXTERNAL CALIBRATION TO PROPENSTY SCORE ANALYSIS
Although covariate measurement error is likely the norm rather than the exception, methods for handling covariate measurement error in propensity score methods have not been widely investigated. We consider a multiple imputation-based approach that uses an external calibration sample with information on the true and mismeasured covariates, Multiple Imputation for External Calibration (MI-EC), to correct for the measurement error, and investigate its performance using simulation studies. As expected, using the covariate measured with error leads to bias in the treatment effect estimate. In contrast, the MI-EC method can eliminate almost all the bias. We confirm that the outcome must be used in the imputation process to obtain good results, a finding related to the idea of congenial imputation and analysis in the broader multiple imputation literature. We illustrate the MI-EC approach using a motivating example estimating the effects of living in a disadvantaged neighborhood on mental health and substance use outcomes among adolescents. These results show that estimating the propensity score using covariates measured with error leads to biased estimates of treatment effects, but when a calibration data set is available, MI-EC can be used to help correct for such bias
Improving health and education outcomes for children in remote communities: A cross-sector and developmental evaluation approach
Early childhood is one of the most influential developmental life stages. Attainments at this stage will have implications for the quality of life children experience as they transition to adulthood. Children residing in remote Australia are exposed to socioeconomic disadvantage that can contribute to developmental delays and resultant poorer education and health outcomes. Complex contributing factors in far west New South Wales have resulted in children with speech and fine motor skill delays experiencing no to limited access to allied health services for a number of decades. More recently, growing awareness that no single policy, government agency, or program could effectively respond to these complexities or ensure appropriate allied health service access for children in these communities has led to the development of the Allied Health in Outback Schools Program, which has been operational since 2009. The program is underpinned by cross-sector partnerships and a shared aspirational aim to improve the developmental outcomes of children to enhance their later life opportunities. It was identified early that the initiative had the potential to deliver mutually beneficial outcomes for communities and participating partner organisations.Over the last five years the program has been the catalyst for partnership consolidation, expansion and diversification. The developmental evaluation approach to continuous program adaptation and refinement has provided valuable insights that have informed health and education policy and enabled the program to be responsive to changing community needs, emerging policy and funding reforms.This article explores the evolution of the program partnerships, their contribution to program success and longevity, and their capacity to respond to an emergent and dynamic environment. The authors propose that a community-centred and developmental approach to program innovation and implementation in remote locations is required. This is based on the premise that contemporary linear, logic-based policy development and funding allocations, with predetermined program deliverables and outcomes, are no longer capable of responding appropriately to the complexities experienced by remote communities.Keywords: allied health, remote communities, cross-sectoral partnerships, service learnin
Developing and evaluating a computerized adaptive testing version of the Word Part Levels Test
The knowledge about affix plays a vital role in the development of word knowledge and vocabulary acquisition. A test for diagnostic information on the level of affix knowledge would be useful in order to inform the test users of what learners have gained or lacked in this integral component of vocabulary knowledge. This paper reports the development and evaluation of a computerized adaptive testing (CAT) version of the Word Part Levels Test (WPLT), created by Sasao and Webb (2017). The CAT-WPLT was developed to maximize further the effectiveness of the WPLT as a diagnostic test. It was administered to 760 Japanese university EFL (English as a foreign language) learners. The evaluation was based on the comparison of measurement accuracy with the fixed-item version of the WPLT. The results show that the CAT-WPLT can provide test users with diagnostic information on test-taker’s strengths and weaknesses in affix knowledge with smaller number of items and with the same or greater precision than the previous versions of the WPLT. Pedagogical implications for using the CAT-WPLT are discussed along with issues in utilizing computer adaptivity.This study was funded by The Japan Society for the Promotion of Science, KAKENHI Numbers 26704006 and 16K13273
Quivers of monoids with basic algebras
We compute the quiver of any monoid that has a basic algebra over an
algebraically closed field of characteristic zero. More generally, we reduce
the computation of the quiver over a splitting field of a class of monoids that
we term rectangular monoids (in the semigroup theory literature the class is
known as ) to representation theoretic computations for group
algebras of maximal subgroups. Hence in good characteristic for the maximal
subgroups, this gives an essentially complete computation. Since groups are
examples of rectangular monoids, we cannot hope to do better than this.
For the subclass of -trivial monoids, we also provide a semigroup
theoretic description of the projective indecomposables and compute the Cartan
matrix.Comment: Minor corrections and improvements to exposition were made. Some
theorem statements were simplified. Also we made a language change. Several
of our results are more naturally expressed using the language of Karoubi
envelopes and irreducible morphisms. There are no substantial changes in
actual result
Norden, reframed
This paper calls for Norden to be understood as a metaframe. Related formulations like “Nordic art” or “Nordic welfare” function as mesoframes. These trigger multiple framing devices. A cache of related framing devices constitutes a framing archive. Framing devices work best when operating unobtrusively such that inclusions, exclusions and inconsistencies are condoned or naturalised. Their artifice, however, becomes apparent whenever a frame is questioned. Questioning or criticising a frame gives rise to a framing dispute. The theoretical justification for these typologies is provided at the outset. This schema is then applied to a select range of empirical examples drawn largely from the disciplinary frames (Ernst 1996) of art history and museum studies. Despite this specificity it is envisaged that the general principles set out below can and will be used to address a variety of devices, disputes and archives in Norden and beyond
Using glossaries to increase the lexical coverage of television programs
This study examined the extent to which glossaries may affect the percentage of known words (coverage) in television programs. The transcripts of 51 episodes of 2 television programs (House and Grey’s Anatomy) were analyzed using Range (Heatley, Nation, & Coxhead, 2002) to create glossaries consisting of the low-frequency (less frequent than the 3,000 word level) word families that were encountered 10 or more times in each program. The results showed that coverage of the glossaries was 1.31% for Grey’s Anatomy and 2.26% for House. This was greater than coverage of the 3,001–4,000 most frequent word families in both programs. The cumulative coverage including the glossaries at the 3,000 word level increased to 96.00% for House and 97.20% for Grey’s Anatomy. The findings indicate that glossaries have the potential to improve comprehension of television programs
Lexical correlates of comprehensibility versus accentedness in second language speech
The current project investigated the extent to which several lexical aspects of second language (L2) speech – appropriateness, fluency, variation, sophistication, abstractness, sense relations – interact to influence native speakers’ judgements of comprehensibility (ease of understanding) and accentedness (linguistic nativelikeness). Extemporaneous speech elicited from 40 French speakers of English with varied L2 proficiency levels was first evaluated by 10 native-speaking raters for comprehensibility and accentedness. Subsequently, the dataset was transcribed and analyzed for 12 lexical factors. Various lexical properties of L2 speech were found to be associated with L2 comprehensibility, and especially lexical accuracy (lemma appropriateness) and complexity (polysemy), indicating that these lexical variables are associated with successful L2 communication. In contrast, native speakers’ accent judgements seemed to be linked to surface-level details of lexical content (abstractness) and form (variation, morphological accuracy) rather than to its conceptual and contextual details (e.g., lemma appropriateness, polysemy)
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