1,201 research outputs found
Development of audiovisual comprehension skills in prelingually deaf children with cochlear implants
Objective: The present study investigated the development of audiovisual comprehension skills in prelingually deaf children who received cochlear implants.
Design: We analyzed results obtained with the Common Phrases (Robbins et al., 1995) test of sentence comprehension from 80 prelingually deaf children with cochlear implants who were enrolled in a longitudinal study, from pre-implantation to 5 years after implantation.
Results: The results revealed that prelingually deaf children with cochlear implants performed better under audiovisual (AV) presentation compared with auditory-alone (A-alone) or visual-alone (V-alone) conditions. AV sentence comprehension skills were found to be strongly correlated with several clinical outcome measures of speech perception, speech intelligibility, and language. Finally, pre-implantation V-alone performance on the Common Phrases test was strongly correlated with 3-year postimplantation performance on clinical outcome measures of speech perception, speech intelligibility, and language skills.
Conclusions: The results suggest that lipreading skills and AV speech perception reflect a common source of variance associated with the development of phonological processing skills that is shared among a wide range of speech and language outcome measures
A longitudinal study of audiovisual speech perception by hearing-impaired children with cochlear implants
The present study investigated the development of audiovisual speech perception skills in children who are prelingually deaf and received cochlear implants. We analyzed results from the Pediatric Speech Intelligibility (Jerger, Lewis, Hawkins, & Jerger, 1980) test of audiovisual spoken word and sentence recognition skills obtained from a large group of young children with cochlear implants enrolled in a longitudinal study, from pre-implantation to 3 years post-implantation. The results revealed better performance under the audiovisual presentation condition compared with auditory-alone and visual-alone conditions. Performance in all three conditions improved over time following implantation. The results also revealed differential effects of early sensory and linguistic experience. Children from oral communication (OC) education backgrounds performed better overall than children from total communication (TC backgrounds. Finally, children in the early-implanted group performed better than children in the late-implanted group in the auditory-alone presentation condition after 2 years of cochlear implant use, whereas children in the late-implanted group performed better than children in the early-implanted group in the visual-alone condition. The results of the present study suggest that measures of audiovisual speech perception may provide new methods to assess hearing, speech, and language development in young children with cochlear implants
Magnetotransport studies of Superconducting PrFeAsTeO
We report a detailed study of the electrical transport properties of single
crystals of PrFeAsTeO, a recently discovered iron-based
superconductor. Resistivity, Hall effect and magnetoresistance are measured in
a broad temperature range revealing the role of electrons as dominant charge
carriers. The significant temperature dependence of the Hall coefficient and
the violation of Kohler's law indicate multiband effects in this compound. The
upper critical field and the magnetic anisotropy are investigated in fields up
to 16 T, applied parallel and perpendicular to the crystallographic c-axis.
Hydrostatic pressure up to 2 GPa linearly increases the critical temperature
and the resistivity residual ratio. A simple two-band model is used to describe
the transport and magnetic properties of PrFeAsTeO. The
model can successfully explain the strongly temperature dependent negative Hall
coefficient and the high magnetic anisotropy assuming that the mobility of
electrons is higher than that of holes
L4Fe2As2Te1-xO4-yFy (L = Pr, Sm, Gd): a layered oxypnictide superconductor with Tc up to 45 K
The synthesis, structural and physical properties of iron lanthanide
oxypnictide superconductors, L4Fe2As2Te1-xO4 (L = Pr, Sm, Gd), with transition
temperature at ~ 25 K are reported. Single crystals have been grown at high
pressure using cubic anvil technique. The crystal structure consists of layers
of L2O2 tetrahedra separated by alternating layers of chains of Te and of
Fe2As2 tetrahedra: -L2O2-Te-L2O2-Fe2As2-L2O2-Te-L2O2- (space group: I4/mmm, a ~
4.0, c ~ 29.6 {\AA}). Substitution of oxygen by fluorine increases the critical
temperature, e.g. in Gd4Fe2As2Te1-xOyF4-y up to 45 K. Magnetic torque
measurements reveal an anisotropy of the penetration depths of ~31.Comment: 8 figures, 4 table
Hairy fleabane (Conyza bonarienis) response to saflufenacil in association with different formulations of glyphosate subjected to simulated rainfall
Saflufenacil has been used to control glyphosate resistant weeds, including hairy
fleabane. There are several glyphosate formulations, which are related to different salts and
adjuvants. Differences between these formulations may result in variations in efficacy, especially
in the face of unfavorable environmental conditions, such as the occurrence of unexpected rainfall
after application. The objective of this study was to evaluate the control of hairy fleabane with
saflufenacil in tank mix with different formulations of glyphosate subjected to simulated rainfall
after application. The treatments evaluated were salts of glyphosate (isopropylamine, potassium
and ammonium salt), different periods of simulated rainfall after herbicide application (30, 120
and 240 min, and no rainfall), and the presence or absence of saflufenacil and a non-ionic
adjuvant. Absorption of saflufenacil by hairy fleabane is rapid, since simulated rainfall after 30
min after application did not result in loss of efficiency when the herbicide is applied with
adjuvant. The association of isopropylamine and ammonium salts of glyphosate with saflufenacil
increases the control of hairy fleabane and prevents the occurrence of regrowth when rainfall
occurs at 30 min after the application. The occurrence of simulated rainfall after 240 min reduces
the glyphosate efficiency by 30%, 15% and 60% for the isopropylamine, potassium and
ammonium salt formulations, respectively. The addition of adjuvant improves the efficiency of
glyphosate salt of potassium by 40%. The response of the mixture of glyphosate and saflufenacil
is variable, mainly in situations of rainfall after application
Theory of mind acquisition in children who are deaf: The importance of early identification and communication access
Objectives: The aim of this study was to compare Theory of Mind (ToM) acquisition in typically-hearing preschool-age children (TH), and deaf children of hearing parents (DCHP) who received a cochlear implant by 18 months of age, to determine if early access to spoken language via a cochlear implant affected ToM acquisition.
Methods: Participants included 25 children with cochlear implants ages 3.0 to 6.5 years and 25 age-matched children with TH all of whom were enrolled in preschools with typical peer models. The test battery included measures of expressive and receptive language and ToM.
Results: There were no differences between DCHP and TH peers on language or ToM performance. Hearing age was significantly different; DCHP had been exposed to spoken language for less time than their hearing counterparts by approximately 12 months. Language skills were correlated with ToM after controlling for chronological age.
Discussion: Early cochlear implantation may ameliorate some of the deleterious effects of congenital, profound deafness on oral language development; this could positively influence the development of social cognition.
Conclusions: Children who are deaf who receive a cochlear implant early and who have good oral language skills are more likely to acquire ToM in a typical time frame.
Key words: Cochlear implants, theory of mind, social cognition, languag
Speech Communication
Contains reports on three research projects.National Institutes of Health (Grant 5 RO1 NS04332-13)National Institutes of Health (Grant 1 T32 NS07040-01)Joint Services Electronics Program (Contract DAAB07-75-C-1346
Neurocognitive factors in sensory restoration of early deafness: a connectome model
Progress in biomedical technology (cochlear, vestibular, and retinal implants) has led to remarkable success in neurosensory restoration, particularly in the auditory system. However, outcomes vary considerably, even after accounting for comorbidity-for example, after cochlear implantation, some deaf children develop spoken language skills approaching those of their hearing peers, whereas other children fail to do so. Here, we review evidence that auditory deprivation has widespread effects on brain development, affecting the capacity to process information beyond the auditory system. After sensory loss and deafness, the brain's effective connectivity is altered within the auditory system, between sensory systems, and between the auditory system and centres serving higher order neurocognitive functions. As a result, congenital sensory loss could be thought of as a connectome disease, with interindividual variability in the brain's adaptation to sensory loss underpinning much of the observed variation in outcome of cochlear implantation. Different executive functions, sequential processing, and concept formation are at particular risk in deaf children. A battery of clinical tests can allow early identification of neurocognitive risk factors. Intervention strategies that address these impairments with a personalised approach, taking interindividual variations into account, will further improve outcomes
Edge channel confinement in a bilayer graphene -- quantum dot
We combine electrostatic and magnetic confinement to define a quantum dot in
bilayer graphene. The employed geometry couples -doped reservoirs to a
-doped dot. At magnetic field values around T, Coulomb blockade is
observed. This demonstrates that the coupling of the co-propagating modes at
the - interface is weak enough to form a tunnel barrier, facilitating
transport of single charge carriers onto the dot. This result may be of use for
quantum Hall interferometry experiments
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