Using a Database of Typical Speakers to Describe the Expository Language Skills of Children with Language Impairment

Purpose. This study examined the expository language skills of older students with language impairment (LI) in relation to a large database of typically developing (TD) students. The purpose of the study was to investigate whether comparing language samples to the database allowed users to distinguish between adolescents with LI and those with typical language, and develop individual profiles of relative strengths and weaknesses in children with LI. Methods. School speech-language pathologists elicited expository language samples from high school students with LI (N = 9; mean age = 16;8 [years;months]) by asking them to explain how to play their favorite game or sport as if speaking to a naïve listener. Language samples were transcribed using Systematic Analysis of Language Transcripts (SALT; Miller & Iglesias, 2012), and analyses were completed to compare the performance of students with LI to a large database of samples from TD children in nine language measures. To develop individual expository language skill profiles of relative strengths and weaknesses, the scores of students with LI were compared to their own overall performance on the expository task. Individual profiles were compared to determine whether subgroups of LI appeared. Results. Analysis revealed distinct profiles of relative strengths and weaknesses for eight of the nine participants. One student with LI demonstrated a relatively equal level of performance across all language measures. When individual participants’ scores were compared to the database of TD peers matched in chronological age, all adolescents with LI demonstrated performance at least one standard deviation lower than the database mean in at least two language measures. Conclusions. Expository language sample analysis facilitated the development of individual profiles of strengths and weaknesses in this sample of adolescents with LI. Analysis of expository performance in a larger sample of older students with LI will help determine the number and compositon of linguistic profiles, which specific language measures are most effective in differential diagnosis of LI, and whether this expository task is effective in distinguishing students with LI from those with TD language. Due to the small sample size, the results of this study should be considered preliminary and interpreted with caution

Dependence of interface conductivity on relevant physical parameters in polarized Fermi mixtures

We consider a mass-asymmetric polarized Fermi system in the presence of Hartree-Fock (HF) potentials. We concentrate on the BCS regime with various interaction strengths and numerically obtain the allowed values of the chemical and HF potentials, as well as the mass ratio. The functional dependence of the heat conductivity of the N-SF interface on relevant physical parameters, namely the temperature, the mass ratio, and the interaction strength, is obtained. In particular, we show that the interface conductivity starts to drop with decreasing temperature at the temperature, $T_{\text{m}}$, where the mean kinetic energy of the particles is just sufficient to overcome the SF gap. We obtain $T_{\text{m}}$ as a function of the mass ratio and the interaction strength. The variation of the heat conductivity, at fixed temperature, with the HF potentials and the imbalance chemical potential is also obtained. Finally, because the range of relevant temperatures increases for larger values of the mass ratio, we consider the $^6\text{Li}$-$^{40}\text{K}$ mixture separately by taking the temperature dependence of the pair potential into account.Comment: To appear in Physica C (2012

Linear response of heat conductivity of normal-superfluid interface of a polarized Fermi gas to orbital magnetic field

Using perturbed Bogoliubov equations, we study the linear response to a weak orbital magnetic field of the heat conductivity of the normal-superfluid interface of a polarized Fermi gas at sufficiently low temperature. We consider the various scattering regions of the BCS regime and analytically obtain the transmission coefficients and the heat conductivity across the interface in an arbitrary weak orbital field. For a definite choice of the field, we consider various values of the scattering length in the BCS range and numerically obtain the allowed values of the average and species-imbalance chemical potentials. Thus, taking Andreev reflection into account, we describe how the heat conductivity is affected by the field and the species imbalance. In particular, we show that the additional heat conductivity due to the orbital field increases with the species imbalance, which is more noticeable at higher temperatures. Our results indicate how the heat conductivity may be controlled, which is relevant to sensitive magnetic field sensors/regulators at the interface.Comment: To appear in Physica B (2011