bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors That Influence Lexical and Semantic Fast Mapping of Young Children With Specific Language Impairment
Authors: Alt Mary , Plante Elena
Published: May 2007

Purpose

This purpose of this study was to investigate the lexical and semantic fast mapping ability of young children with specific language impairment (SLI) and normal language (NL), with a specific emphasis on the influence of phonological factors.

Method

The study included 46 children (mean age 58 months), half with SLI and half with NL. Children were asked to fast map visual information only, visual-plus-nonlinguistic-auditory information, and visual-plus-linguistic-auditory information. A mixed design was used to compare children across and within groups.

Results

Children with SLI performed worse than children with NL overall. The SLI group showed specific deficits in semantic fast mapping when they saw visual information only. This condition may have disrupted encoding because it varied from the expected auditory and visual pattern. The children with SLI also performed poorly when they were asked to map phonotactically infrequent linguistic information and when the difficulty of the task increased. A nonword repetition task was correlated with both semantic and lexical fast mapping.

Conclusions

The findings are discussed in the light of their support for a limited capacity model of processing, as well as the impact of phonology on word learning.
Reliability Issues and Solutions for Coding Social Communication Performance in Classroom Settings
Authors: Olswang Lesley B. , Svensson Liselotte , Coggins Truman E. , Beilinson Jill S. , Donaldson Amy L.
Published: May 2007

Purpose

To explore the utility of time-interval analysis for documenting the reliability of coding social communication performance of children in classroom settings. Of particular interest was finding a method for determining whether independent observers could reliably judge both occurrence and duration of ongoing behavioral dimensions for describing social communication performance.

Method

Four coders participated in this study. They observed and independently coded 6 social communication behavioral dimensions using handheld computers. The dimensions were mutually exclusive and accounted for all verbal and nonverbal productions during a specified time frame. The technology allowed for coding frequency and duration for each entered code. Data were collected from 20 different 2-min video segments of children in kindergarten through 3rd-grade classrooms. Data were analyzed for interobserver and intraobserver agreements using time-interval sorting and Cohen’s kappa. Further, interval size and total observation length were manipulated to determine their influence on reliability.

Results

The data revealed interval sorting and kappa to be a suitable method for examining reliability of occurrence and duration of ongoing social communication behavioral dimensions. Nearly all comparisons yielded medium to large kappa values; interval size and length of observation minimally affected results.

Implications

The analysis procedure described in this research solves a challenge in reliability: comparing coding by independent observers of both occurrence and duration of behaviors. Results indicate the utility of a new coding taxonomy and technology for application in online observations of social communication in a classroom setting.
Song Recognition by Children and Adolescents With Cochlear Implants
Authors: Vongpaisal Tara , Trehub Sandra E. , Schellenberg E. Glenn
Published: May 2007

Purpose

To assess song recognition and pitch perception in prelingually deaf individuals with cochlear implants (CIs).

Method

Fifteen hearing children (5–8 years) and 15 adults heard different versions of familiar popular songs—original (vocal + instrumental), original instrumental, and synthesized melody versions—and identified the song in a closed-set task (Experiment 1). Ten CI users (8–18 years) and age-matched hearing listeners performed the same task (Experiment 2). Ten CI users (8–19 years) and 10 hearing 8-years-olds were required to detect pitch changes in repeating-tone contexts (Experiment 3). Finally, 8 CI users (6–19 years) and 13 hearing 5-year-olds were required to detect subtle pitch changes in a more challenging melodic context (Experiment 4).

Results

CI users performed more poorly than hearing listeners in all conditions. They succeeded in identifying the original and instrumental versions of familiar recorded songs, and they evaluated them favorably, but they could not identify the melody versions. Although CI users could detect a 0.5-semitone change in the simple context, they failed to detect a 1-semitone change in the more difficult melodic context.

Conclusion

Current implant processors provide insufficient spectral detail for some aspects of music perception, but they do not preclude young implant users' enjoyment of music.
Birth Control Pills and Nonprofessional Voice: Acoustic Analyses
Authors: Amir Ofer , Biron-Shental Tal , Shabtai Esther
Published: May 2007

Purpose

Two studies are presented here. Study 1 was aimed at evaluating whether the voice characteristics of women who use birth control pills that contain different progestins differ from the voice characteristics of a control group. Study 2 presents a meta-analysis that combined the results of Study 1 with those from 3 recent studies that compared voices of women who use and do not use birth control pills.

Method

In Study 1, voice samples from 30 women with no history of voice training, who use pills with different progestins (drospirenone, desogestrel, gestodene), and 10 women who do not use the pill were recorded at specific time points across the menstrual cycle and were analyzed acoustically. In Study 2, results from Study 1 were analyzed jointly with results from three recent studies, which used similar methodologies.

Results

Results of Study 1 did not reveal acoustic differences in sustained phonation of vowels across the pill groups and controls. Results of the meta-analysis performed in Study 2 indicated that pill users exhibited lower jitter and shimmer values on sustained vowels, whereas no difference of fundamental frequency was observed among women who use the pill.

Conclusions

These results support findings from previous studies, which suggested that no adverse effect on voice was detected among nonprofessional speakers who use new-generation monophasic birth control pills, for the measures studied. Furthermore, results of the meta-analysis suggested that some acoustic properties of the voice, which are reflected in perturbation measures in sustained vowels, may be improved among women who use the pill.
Alterations in CNS Activity Induced by Botulinum Toxin Treatment in Spasmodic Dysphonia: An H215O PET Study
Authors: Ali S. Omar , Thomassen Michael , Schulz Geralyn M. , Hosey Lara A. , Varga Mary , Ludlow Christy L. , Braun Allen R.
Published: May 2007

Speech-related changes in regional cerebral blood flow (rCBF) were measured using H215O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age- and gender-matched volunteers without neurological disorders. Scans were acquired at rest and during production of continuous narrative speech and whispered speech. Speech was recorded during scan acquisition for offline quantification of voice breaks, pitch breaks, and percentage aperiodicity to assess correlations between treatment-related changes in rCBF and clinical improvement. Results demonstrated that speech-related responses in heteromodal sensory areas were significantly reduced in persons with ADSD, compared with volunteers, before the administration of BTX. Three to 4 weeks after BTX injection, speech-related responses were significantly augmented in these regions and in left hemisphere motor areas commonly associated with oral-laryngeal motor control. This pattern of responses was most strongly correlated with the objective measures of clinical improvement (decreases in the frequency of voice breaks, pitch breaks, and percentage aperiodicity). These data suggest a pathophysiological model for ADSD in which BTX treatment results in more efficient cortical processing of sensory information, making this information available to motor areas that use it to more effectively regulate laryngeal movements.
Interspeaker Variation in Habitual Speaking Rate: Additional Evidence
Authors: Tsao Ying-Chiao , Weismer Gary , Iqbal Kamran
Published: May 2007

Purpose

The purpose of the present study was to test the hypothesis that talkers previously classified by Y.-C. Tsao and G. Weismer (1997) as habitually fast versus habitually slow would show differences in the way they manipulated articulation rate across the rate continuum.

Method

Thirty talkers previously classified by Tsao and Weismer (1997) as having habitually slow (
n
= 15; 7 males, 8 females) and habitually fast (
n
= 15; 8 males, 7 females) articulation rates produced a single sentence at 7 different rates, using a magnitude production paradigm. Hence, the participants were not randomly assigned to conditions.

Results

Quadratic regression functions relating measured to intended articulation rates were all statistically significant, and most important, there were significant differences between the slow and fast groups in the
y
intercepts of the functions, for both males and females.

Conclusions

This study provides a constructive replication of Tsao and Weismer (1997), showing a difference between slow and fast talkers with a new set of speech materials and in a new task. The findings appear to be consistent with a biological basis for intertalker rate differences.
Prelinguistic Predictors of Language Outcome at 3 Years of Age
Authors: Watt Nola , Wetherby Amy , Shumway Stacy
Published: May 2007

Purpose

The purpose of this study was to examine the predictive validity of a collection of prelinguistic skills measured longitudinally in the 2nd year of life to language outcome in the 3rd year in children with typical language development.

Method

A collection of prelinguistic skills was assessed in 160 children early (
M
= 14.31 months;
SD
= 1.36) and late (
M
= 19.76 months;
SD
= 1.16) in their 2nd year by using the Communication and Symbolic Behavior Scales Developmental Profile Behavior Sample (A. Wetherby & B. Prizant, 2002). The relation between the prelinguistic skills and the receptive and expressive language near the 3rd birthday was examined.

Results

Significant correlations were observed between many prelinguistic skills and language outcome. Regression analyses indicated that comprehension both early and late contributed unique variance to receptive and expressive language outcome. In addition, early in the 2nd year, inventory of conventional gestures contributed uniquely to receptive language outcome, and acts for joint attention contributed uniquely to expressive outcome. Late in the 2nd year, inventory of consonants contributed uniquely to expressive outcome.

Conclusions

The findings demonstrate continuity between prelinguistic and linguistic skills and how individual differences in a number of prelinguistic skills contribute collectively and uniquely to language outcome in typically developing children.
Understanding Conservation Delays in Children With Specific Language Impairment: Task Representations Revealed in Speech and Gesture
Authors: Mainela-Arnold Elina , Evans Julia L. , Alibali Martha W.
Published: May 2007

Purpose

The authors investigated mental representations of Piagetian conservation tasks in children with specific language impairment (SLI) and typically developing peers. Children with SLI have normal nonverbal intelligence; however, they exhibit difficulties in Piagetian conservation tasks. The authors tested the hypothesis that conservation difficulties may be due to the degree to which children with SLI rely on external perceptual features of the task as opposed to internal cognitive knowledge about transformation.

Method

Twenty-nine children participated, 12 children with SLI (ages 7;0–10;5) and 17 typically developing peers (ages 5;4–10;9) who were matched either on chronological age (CA) task or on judgments on the conservation task (conservation matched [CM]). Children solved conservation tasks and then explained their reasoning. Explanations produced in speech and gesture were analyzed.

Results

In speech, children in the SLI group expressed proportionately fewer internal explanations than the CA group, but a similar proportion of internal explanations as compared with the younger CM group. In gesture, children with SLI did not differ from either CA or CM children.

Conclusions

Children with SLI have weak internal representations of the concept of conservation, similar to those of younger children. Conservation representations appear to be closely related to language skills and verbal working memory.
Effects of Talker Variability on Vowel Recognition in Cochlear Implants
Authors: Chang Yi-ping , Fu Qian-Jie
Published: May 2007

Purpose

To investigate the effects of talker variability on vowel recognition by cochlear implant (CI) users and by normal-hearing (NH) participants listening to 4-channel acoustic CI simulations.

Method

CI users were tested with their clinically assigned speech processors. For NH participants, 3 CI processors were simulated, using different combinations of carrier type and temporal envelope cutoff frequency (noise band/160 Hz, sine wave/160 Hz, and sine wave/20 Hz). Vowel recognition was measured for 4 talkers, presented in either a single-talker context (1 talker per test block) or a multi-talker context (4 talkers per test block).

Results

CI users' vowel recognition was significantly poorer in the multi-talker context than in the single-talker context. When noise-band carriers were used in the simulations, NH performance was not significantly affected by talker variability. However, when sine-wave carriers were used in the simulations, NH performance was significantly affected by talker variability in both envelope filter conditions.

Conclusions

Because fundamental frequency was not preserved by the 20-Hz envelope filter and only partially preserved by the 160-Hz envelope filter, both spectral and temporal cues contributed to the talker variability effects observed with sine-wave carriers. Similarly, spectral and temporal cues may have contributed to the talker variability effects observed with CI participants.
On the Structure of Phoneme Categories in Listeners With Cochlear Implants
Authors: Lane Harlan , Denny Margaret , Guenther Frank H. , Hanson Helen M. , Marrone Nicole , Matthies Melanie L. , Perkell Joseph S. , Stockmann Ellen , Tiede Mark , Vick Jennell , Zandipour Majid
Published: May 2007

Purpose

To describe cochlear implant users' phoneme labeling, discrimination, and prototypes for a vowel and a sibilant contrast, and to assess the effects of 1 year’s experience with prosthetic hearing.

Method

Based on naturally produced clear examples of “boot,” “beet,” “said,” and “shed” by 1 male and 1 female speaker, continua with 13 stimuli were synthesized for each contrast. Seven hearing controls labeled those stimuli and assigned them goodness ratings, as did 7 implant users at 1-month postimplant. One year later, these measures were repeated, and within category discrimination,
d
′, was assessed.

Results

Compared with controls, implant users' vowel and sibilant labeling slopes were substantially shallower but improved over 1 year of prosthesis use. Their sensitivity to phonetic differences within phoneme categories was about half that of controls. The slopes of their goodness rating functions were shallower and did not improve. Their prototypes for the sibilant contrast (but not the vowels) were closer to one another and did not improve by moving apart.

Conclusions

Implant users' phoneme labeling and within-category perceptual structure were anomalous at 1-month postimplant. After 1 year of prosthesis use, phoneme labeling categories had sharpened but within category discrimination was well below that of hearing controls.
The Objective and Subjective Evaluation of Multichannel Expansion in Wide Dynamic Range Compression Hearing Instruments
Authors: Plyler Patrick N. , Lowery Kristy J. , Hamby Hilary M. , Trine Timothy D.
Published: May 2007

Purpose

The effects of multichannel expansion on the objective and subjective evaluation of 20 listeners fitted binaurally with 4-channel, digital in-the-ear hearing instruments were investigated.

Method

Objective evaluations were conducted in quiet using the Connected Speech Test (CST) and in noise using the Hearing in Noise Test (HINT) at 40, 50, and 60 dB SPL. Subjective evaluations were conducted by having each participant (a) rate their satisfaction regarding the amount of noise reduction they perceived daily and (b) indicate which expansion condition they preferred overall after a 2-week trial. Three expansion settings were programmed into the hearing aids: 4-channel expansion, expansion restricted to Channels 1 and 2 only, and expansion off.

Results

Listeners performed significantly better in quiet (CST) and in noise (HINT) for the off condition than for either multichannel condition; however, restricting expansion to Channels 1 and 2 improved objective performance in quiet and in noise relative to the 4-channel condition. Conversely, satisfaction ratings were significantly greater for both multichannel conditions than for the off condition; however, satisfaction ratings were similar for the restricted and the 4-channel conditions. Overall, listeners preferred any form of multichannel expansion to no expansion; however, overall preference was similar for the restricted and the 4-channel conditions.

Conclusions

Hearing instrument users prefer the use of multichannel expansion despite the fact multichannel expansion may significantly reduce the recognition of low-level speech in quiet and in noise. Although restricting expansion to Channels 1 and 2 (i.e., 2000 Hz and below) maintained subjective benefit for wide dynamic range compression hearing instrument users, the recognition of low-level speech was not completely preserved.
Children’s Weighting Strategies for Word-Final Stop Voicing Are Not Explained by Auditory Sensitivities
Authors: Nittrouer Susan , Lowenstein Joanna H.
Published: May 2007

Purpose

It has been reported that children and adults weight differently the various acoustic properties of the speech signal that support phonetic decisions. This finding is generally attributed to the fact that the amount of weight assigned to various acoustic properties by adults varies across languages, and that children have not yet discovered the mature weighting strategies of their own native languages. But an alternative explanation exists: Perhaps children’s auditory sensitivities for some acoustic properties of speech are poorer than those of adults, and children cannot categorize stimuli based on properties to which they are not keenly sensitive. The purpose of the current study was to test that hypothesis.

Method

Edited-natural, synthetic-formant, and sine wave stimuli were all used, and all were modeled after words with voiced and voiceless final stops. Adults and children (5 and 7 years of age) listened to pairs of stimuli in 5 conditions: 2 involving a temporal property (1 with speech and 1 with nonspeech stimuli) and 3 involving a spectral property (1 with speech and 2 with nonspeech stimuli). An AX discrimination task was used in which a standard stimulus (A) was compared with all other stimuli (X) equal numbers of times (method of constant stimuli).

Results

Adults and children had similar difference thresholds (i.e., 50% point on the discrimination function) for 2 of the 3 sets of nonspeech stimuli (1 temporal and 1 spectral), but children’s thresholds were greater for both sets of speech stimuli.

Conclusion

Results are interpreted as evidence that children’s auditory sensitivities are adequate to support weighting strategies similar to those of adults, and so observed differences between children and adults in speech perception cannot be explained by differences in auditory perception. Furthermore, it is concluded that listeners bring expectations to the listening task about the nature of the signals they are hearing based on their experiences with those signals.
The Effect of Temporal Adverbials on Past Tense Production by Children With Specific Language Impairment
Authors: Krantz Laurie R. , Leonard Laurence B.
Published: May 2007

Purpose

Children with specific language impairment (SLI) often fail to produce past tense forms in obligatory contexts, although the factors affecting such inconsistency are not well understood. This study examined the influence of accompanying temporal adverbials (e.g.,
just, already
) on the past tense production of these children.

Method

Fifteen preschool-aged children with SLI, 15 typically developing children matched for age (TD–A) and 15 younger typically developing children matched for mean length of utterance (TD–MLU) participated in the study. The children responded to probes that obligated the use of past tense forms. The verbal context provided by the experimenter for half of the items included a temporal adverbial.

Results

Overall, the SLI and TD–MLU groups produced past tense less frequently than the children in the TD–A group, and there were no significant differences between the SLI and the TD–MLU groups. However, both the SLI and the TD–MLU participants produced past tense forms less frequently when temporal adverbials were included than when they were absent.

Conclusions

These findings suggest that the tendency to use past tense by the children with SLI and their younger MLU-matched peers may not have been independent of other types of temporal information.
The Role of Selected Lexical Factors on Confrontation Naming Accuracy, Speed, and Fluency in Adults Who Do and Do Not Stutter
Authors: Newman Rochelle S. , Bernstein Ratner Nan
Published: May 2007

Purpose

The purpose of this study was to investigate whether lexical access in adults who stutter (AWS) differs from that in people who do not stutter. Specifically, the authors examined the role of 3 lexical factors on naming speed, accuracy, and fluency: word frequency, neighborhood density, and neighborhood frequency. If stuttering results from an impairment in lexical access, these factors were hypothesized to differentially affect AWS performance on a confrontation naming task.

Method

Twenty-five AWS and 25 normally fluent comparison speakers, matched for age and education, participated in a confrontation naming task designed to explore within-speaker performance on naming accuracy, speed, and fluency based on stimulus word frequency and neighborhood characteristics. Accuracy, fluency, and reaction time (from acoustic waveform analysis) were computed.

Results

In general, AWS demonstrated the same effects of lexical factors on their naming as did adults who do not stutter. However, accuracy of naming was reduced for AWS. Stuttering rate was influenced by word frequency but not other factors.

Conclusions

Results suggest that AWS could have a fundamental deficit in lexical retrieval, but this deficit is unlikely to be at the level of the word’s abstract phonological representation. Implications for further research are discussed.
Phonological Neighborhood and Word Frequency Effects in the Stuttered Disfluencies of Children Who Stutter
Authors: Anderson Julie D.
Published: May 2007

Purpose

The purpose of this study was to examine (a) the role of neighborhood density (number of words that are phonologically similar to a target word) and frequency variables on the stuttering-like disfluencies of preschool children who stutter, and (b) whether these variables have an effect on the type of stuttering-like disfluency produced.

Method

A 500+ word speech sample was obtained from each participant (N= 15). Each stuttered word was randomly paired with the firstly produced word that closely matched it in grammatical class, familiarity, and number of syllables/phonemes. Frequency, neighborhood density, and neighborhood frequency values were obtained for the stuttered and fluent words from an online database.

Results

Findings revealed that stuttered words were lower in frequency and neighborhood frequency than fluent words. Words containing part-word repetitions and sound prolongations were also lower in frequency and/or neighborhood frequency than fluent words, but these frequency variables did not have an effect on single-syllable word repetitions. Neighborhood density failed to influence the susceptibility of words to stuttering, as well as the type of stuttering-like disfluency produced.

Conclusions

In general, findings suggest that neighborhood and frequency variables not only influence the fluency with which words are produced in speech, but also have an impact on the type of stuttering-like disfluency produced.
Ranking Hearing Aid Input–Output Functions for Understanding Low-, Conversational-, and High-Level Speech in Multitalker Babble
Authors: Chung King , Killion Mead C. , Christensen Laurel A.
Published: May 2007

Purpose

To determine the rankings of 6 input–output functions for understanding low-level, conversational, and high-level speech in multitalker babble without manipulating volume control for listeners with normal hearing, flat sensorineural hearing loss, and mildly sloping sensorineural hearing loss.

Method

Peak clipping, compression limiting, and 4 wide dynamic range compression (WDRC) input–output functions were compared in a repeated-measure design. Interactions among the compression characteristics were minimized. Speech and babble were processed and recorded at 3 input levels: 45, 65, and 90 dB sound pressure level. Speech recognition of 3 groups of listeners (n= 6/group) was tested for speech processed by each input–output function and at each input level.

Results

Input–output functions that made low-level speech audible and high-level speech less distorted by avoiding peak clipping or severe compression yielded higher speech recognition scores. These results are consistent with previous findings in the literature.

Conclusion

WDRCs with the low compression ratio region extended to a high input level or with a high compression limiting threshold were the best for speech recognition in babble when the hearing aid user cannot or does not want to manipulate the volume control. Future studies on subjective preferences of different input–output functions are needed.
Physiologic Development of Tongue–Jaw Coordination From Childhood to Adulthood
Authors: Cheng Hei Yan , Murdoch Bruce E. , Goozée Justine V. , Scott Dion
Published: May 2007

Purpose

This investigation aimed to examine the development of tongue–jaw coordination during speech from childhood to adolescence.

Method

Electromagnetic articulography was used to track tongue and jaw motion in 48 children and adults (aged 6–38 years) during productions of /t/ and /k/ embedded in sentences.

Results

The coordinative organization of the tongue and jaw exhibited changes until the age of 8–11 years and continued to undergo refinement into late adolescence. The tongue–tip and tongue–body were observed to develop unique kinematic relations with the jaw. While tongue–tip movement became increasingly synchronized with jaw movement, tongue–body and jaw retained movement independence but developed a more consistent kinematic relation.

Conclusion

The present results support the notion that speech motor development is nonuniform, with a refinement period from mid-childhood to late adolescence.
Speaking-Related Dyspnea in Healthy Adults
Authors: Hoit Jeannette D. , Lansing Robert W. , Perona Kristen E.
Published: May 2007

Purpose

To reveal the qualities and intensity of speaking-related dyspnea in healthy adults under conditions of high ventilatory drive, in which the behavioral and metabolic control of breathing must compete.

Method

Eleven adults read aloud while breathing different levels of inspired carbon dioxide (CO
2
). After the highest level, participants provided unguided descriptions of their experiences and then selected descriptors from a list. On a subsequent day, participants read aloud while breathing high CO
2
as before, then rated air hunger, physical exertion, and mental effort (with definitions provided). Recordings were made of ventilation (with respiratory magnetometers), end-tidal partial pressure of CO
2
, transcutaneous PCO
2
, oxygen saturation, noninvasive blood pressure, heart rate, and the speech signal.

Results

Unguided descriptions were found to reflect the qualities of air hunger, physical exertion (work), mental effort, and speech-related observations. As CO
2
stimulus strength increased, participants experienced increased perception of air hunger, physical exertion, and mental effort. Simultaneous increases were observed in ventilation, tidal volume, end-inspiratory and end-expiratory volumes, expiratory flow during speaking, nonlinguistic junctures, and nonspeech expirations.

Conclusion

Two qualities of speaking-related dyspnea—air hunger and physical exertion—are the same as those reported for many other types of nonspeech dyspnea conditions and, therefore, may share the same physiological mechanisms. The mental effort quality associated with speaking-related dyspnea may reflect a conscious drive to balance speech requirements and ventilatory demands. These findings have implications for developing better ways to evaluate and manage clients with respiratory-based speech problems.
Relations Between Segmental and Motor Variability in Prosodically Complex Nonword Sequences
Authors: Goffman Lisa , Gerken LouAnn , Lucchesi Julie
Published: May 2007

Purpose

To assess how prosodic prominence and hierarchical foot structure influence segmental and articulatory aspects of speech production, specifically segmental accuracy and variability, and oral movement trajectory variability.

Method

Thirty individuals participated: 10 young adults, 10 children who are normally developing, and 10 children diagnosed with specific language impairment. Segmental error and segmental variability and movement trajectory variability were compared in low and high prosodic prominence conditions (i.e., strong and weak syllables) and in different prosodic foot structures.

Results

Between-participants findings were that both groups of children showed more segmental error and segmental variability and more movement trajectory variability than did adults. A similar within-participant pattern of results was observed for all 3 groups. Prosodic prominence influenced both segmental and motor levels of analysis, with weak syllables produced less accurately and with more lip and jaw movement trajectory variability than strong syllables. However, hierarchical foot structure affected segmental but not motor measures of speech production accuracy and variability.

Conclusions

Motor and segmental variables were not consistently aligned. This pattern of results has clinical implications because inferences about motor variability may not directly follow from observations of segmental variability.
Exploring the Utility of Narrative Analysis in Diagnostic Decision Making: Picture-Bound Reference, Elaboration, and Fetal Alcohol Spectrum Disorders
Authors: Thorne John C. , Coggins Truman E. , Carmichael Olson Heather , Astley Susan J.
Published: May 2007

Purpose

To evaluate classification accuracy and clinical feasibility of a narrative analysis tool for identifying children with a fetal alcohol spectrum disorder (FASD).

Method

Picture-elicited narratives generated by 16 age-matched pairs of school-aged children (FASD vs. typical development [TD]) were coded for semantic elaboration and reference strategy by judges who were unaware of age, gender, and group membership of the participants. Receiver operating characteristic (ROC) curves were used to examine the classification accuracy of the resulting set of narrative measures for making 2 classifications: (a) for the 16 children diagnosed with FASD, low performance (n= 7) versus average performance (n= 9) on a standardized expressive language task and (b) FASD (n= 16) versus TD (n= 16).

Results

Combining the rates of semantic elaboration and pragmatically inappropriate reference perfectly matched a classification based on performance on the standardized language task. More importantly, the rate of ambiguous nominal reference was highly accurate in classifying children with an FASD regardless of their performance on the standardized language task (area under the ROC curve = .863, confidence interval = .736–.991).

Conclusion

Results support further study of the diagnostic utility of narrative analysis using discourse level measures of elaboration and children’s strategic use of reference.
Assessing Cortisol Reactivity to a Linguistic Task as a Marker of Stress in Individuals With Left-Hemisphere Stroke and Aphasia
Authors: Laures-Gore Jacqueline , Heim Christine M. , Hsu Yu-Sheng
Published: May 2007

Purpose

In this study, the authors explore a method of measuring physiologic and perceived stress in individuals with aphasia by investigating salivary cortisol reactivity and subjectively perceived stress in response to a standardized linguistic task.

Method

Fifteen individuals with aphasia and 15 age-matched healthy controls participated in a linguistic task involving speaking to an unfamiliar listener and a nonlinguistic task consisting of the Mirror Drawing Test (Starch, 1910). Salivary cortisol samples were taken following a 30-min baseline period, at the beginning and end of each task, and at 10-min intervals throughout the posttask period. Perceptions of stress also were assessed.

Results

No significant difference was found in cortisol levels over time within the group with aphasia between the linguistic and nonlinguistic task; however, the control group demonstrated greater cortisol reactivity during the linguistic task than during the nonlinguistic task. For the linguistic task only, the control group demonstrated greater cortisol reactivity than did the group with aphasia. Both groups perceived greater stress posttask than pretask, although the aphasia group perceived greater stress than did the control group.

Conclusion

Adults with aphasia perceived greater stress than did healthy controls; however, this paradigm did not stimulate salivary cortisol reactivity in the aphasia group. A potential reason for this may be differences in the type or degree of psychosocial variables that are important in modulating stress in this population. Other considerations when developing methods for assessing physiologic stress include habituation and hypothalamic-pituitary-adrenal (HPA) axis dysregulation related to the neurological changes poststroke.
Longitudinal Relationships Between Lexical and Grammatical Development in Typical and Late-Talking Children
Authors: Moyle Maura Jones , Ellis Weismer Susan , Evans Julia L. , Lindstrom Mary J.
Published: May 2007

Purpose

This study examined the longitudinal relationships between lexical and grammatical development in typically developing (TD) and late-talking children for the purposes of testing the single-mechanism account of language acquisition and comparing the developmental trajectories of lexical and grammatical development in late-talking and TD children.

Method

Participants included 30 children identified as late talkers (LTs) at 2;0 (years;months), and 30 TD children matched on age, nonverbal cognition, socioeconomic status, and gender. Data were collected at 5 points between 2;0 and 5;6.

Results

Cross-lagged correlational analyses indicated that TD children showed evidence of bidirectional bootstrapping between lexical and grammatical development between 2;0 and 3;6. Compared with the TD group, LTs exhibited less evidence of syntactic bootstrapping. Linear mixed-effects modeling of language sample data suggested that the relationship between lexical and grammatical growth was similar for the 2 groups.

Conclusion

Lexical and grammatical development were strongly related in both groups, consistent with the single-mechanism account of language acquisition. The results were mixed in terms of finding longitudinal differences in lexical–grammatical relationships between the TD and late-talking children; however, several analyses suggested that for late-talking children, syntactic growth may be less facilitative of lexical development.
Predicting Language Outcomes for Internationally Adopted Children
Authors: Glennen Sharon L.
Published: May 2007

Purpose

Language and speech are difficult to assess in newly arrived internationally adopted children. The purpose of this study was to determine if assessments completed when toddlers were first adopted could predict language outcomes at age 2. Local norms were used to develop early intervention guidelines that were evaluated against age 2 outcomes. Patterns of language emergence were also analyzed.

Method

Twenty-seven children between 11 and 23 months of age adopted from Eastern Europe were followed from adoption through the 1st year home. Results from initial assessments using the Communication and Symbolic Behavior Scales—Developmental Profile (CSBS–DP; A. Wetherby & B. Prizant, 2002) and MacArthur Communicative Development Inventory—Words and Gestures (MCDI–WG; L. Fenson et al., 1993) were compared against speech and language outcomes 1 year later when the children were 2 years of age.

Results

By age 2, receptive language and articulation were developing well; expressive language was still emerging. Initial assessment using the CSBS–DP Behavior Sample and MCDI–WG Words Understood Developmental Quotient predicted age 2 language outcomes. Early intervention guidelines based on these 2 measures had strong positive and negative likelihood ratios (LR) when using age 2 outcomes as the criteria (LR+ = 21.00; LR− = .00). Six of the 27 children (22%) had slow language development in comparison to their peers.

Conclusion

Newly adopted children with delays on prelinguistic and vocabulary comprehension measures were highly likely to have slow language development at age 2. Initial assessments of these abilities should be used to make early intervention decisions.
Self-assembly of fractal nanowires and stripe magnetic domain on stretchable substrate
Authors: Aurongzeb Deeder
Published: May 2007

Magnetic properties of Ni thin films on polydimethylsiloxane (PDMS) are being studied. The author finds that coercivity of the films grown on PDMS is two to three times higher than their rigid counterpart. Magnetic force microscopy studies show that surface morphology and magnetic domains are quite different on elastic substrate. 5nm thick films do not exhibit planar morphology but rather form very long nanowires. The 50nm thick films exhibit in-plane and canted magnetizations with nonmagnetic disordered regions within the thin films. Study suggests that elastomers coupled with magnetic thin films can give rise to interesting material properties.
Absorptive and dispersive optical responses of excitons in a single quantum dot
Authors: Alén Benito , Högele Alexander , Kroner Martin , Seidl Stefan , Karrai Khaled , Warburton Richard J. , Badolato Antonio , Medeiros-Ribeiro Gilberto , Petroff Pierre M.
Published: May 2007

The authors have determined both the real and imaginary parts of the dielectric polarizability of a single quantum dot. The experiment is based on the observation and the manipulation of Rayleigh scattering at photon frequencies near the resonance of an optical exciton transition in single self-assembled InAs and InGaAs quantum dots. The interference between the narrow-band laser field and the weak electromagnetic field coherently scattered by the quantum dot is detected with a cryogenic Fabry-Pérot setup by combined differential transmission and reflectivity measurements.
Design optimization for micromachined low power Mach-Zehnder thermo-optic switch
Authors: Wu Ching-Yi , Lin Puru , Huang Ruey-Shing , Chao Wei-Chung , Lee Mark M. H.
Published: May 2007

The main issue of a Mach-Zehnder interferometer based thermo-optic switch is that it needs large heating power to get adequate phase shift for switching. A device structure of etching in a silicon groove underneath the heated arm of waveguide was to suppress the heat loss through the bulk silicon substrate, hence reducing the required heating power. This study shows that the optimum design of the device is obtained when the silicon etched groove is located asymmetrically with respect to the two waveguide branches; power consumption as low as 49mW and fast response time of a few milliseconds can be achieved.
Generation of narrow-bandwidth picosecond visible pulses from broadband femtosecond pulses for femtosecond stimulated Raman
Authors: Shim Sangdeok , Mathies Richard A.
Published: May 2007

To perform time-resolved vibrational structural studies with femtosecond stimulated Raman spectroscopy, it is desirable to produce tunable transform-limited picosecond pulses in the visible from a femtosecond laser system. The authors demonstrate here the generation of ∼36cm−1 bandwidth tunable picosecond pulses across the entire visible spectral range using a narrow-bandwidth optical parametric amplifier with chirped pulse pumping. These pulses are characterized and used to obtain broadband stimulated Raman spectra with 38cm−1 resolution.
Polarization enhanced “single shot” N14 nuclear quadrupole resonance detection of trinitrotoluene at room temperature
Authors: Lužnik Janko , Pirnat Janez , Jazbinšek Vojko , Apih Tomaž , Gregorovič Alan , Blinc Robert , Seliger Janez , Trontelj Zvonko
Published: May 2007

The authors show that a combination of proton-nitrogen level crossing polarization transfer with a pulsed spin-locking sequence makes N14 nuclear quadrupole resonance (NQR) fast and sensitive enough to be used in routine explosive detection as well as in the pharmaceutical industry for nondestructive chemical analysis of solid samples and polymorph determination. As an example we present “single shot” measurements of the N14 NQR spectra of 15g of trinitrotoluene at room temperature with a total measuring time of 20s.
Engineering white light-emitting Eu-doped ZnO urchins by biopolymer-assisted hydrothermal method
Authors: Gao Shuyan , Zhang Hongjie , Deng Ruiping , Wang Xiaomei , Sun Dehui , Zheng Guoli
Published: May 2007

With the presence of biopolymer-sodium alginate as additive, Eu-doped ZnO (zinc oxide) urchins consisting of nanorods were synthesized through a hydrothermal route. X-ray diffraction pattern makes evident the absence of phase other than würtzite ZnO. Upon excited by 325nm xenon laser, such nanostructured Eu-doped ZnO urchins emit white light, which originates from the luminescence of ZnO and the intra-4f transitions of Eu3+ ions. Besides acting as stabilizing agent, sodium alginate may also sensitize the Eu3+ ions in the nanostructures and facilitate the energy transfer from the host to Eu3+ ions.
The reversible susceptibility tensor of synthetic antiferromagnets
Authors: Cimpoesu Dorin , Stancu Alexandru , Spinu Leonard
Published: May 2007

In this work we propose to study the reversible susceptibility tensor (including the transverse susceptibility components) of a synthetic antiferromagnetic (SAF) structure. This study is motivated by the fact that knowing the magnetic anisotropy of SAF structure is essential for the device functioning and the transverse susceptibility is known as one of the best methods to determine magnetic anisotropy and switching properties of magnetic systems. The starting point of this work is the magnetization’s equation of motion Landau-Lifshitz-Gilbert for the coupled two layers. By solving the inhomogeneous system of linear equations on the magnetization’s spherical coordinate deviations, the susceptibility tensor of the SAF structure is obtained. Simplified equations for the very low frequency case are given. By comparing the plots of the susceptibility versus the applied field with the regular hysteresis loops one concludes that susceptibility experiments are more appropriate for switching investigations of the SAF systems.
Electrical voltage manipulation of ferromagnetic microdomain structures in a ferromagnetic/ferroelectric hybrid structure
Authors: Taniyama T. , Akasaka K. , Fu D. , Itoh M. , Takashima H. , Prijamboedi B.
Published: May 2007

We report on electrical bias voltage manipulation of the magnetic domain structures of patterned ferromagnetic Fe dots on a ferroelectric BaTiO3 underlayer using a scanning probe microscope technique. Piezoresponse force microscopy is used to apply local electric field on the Fe dots/BaTiO3 hybrid structure and to map the ferroelectric domain structures simultaneously. Magnetic force microscope observation also demonstrates that the magnetic domain structures of the Fe dots significantly change with the application of voltage at room temperature through the coupling between piezoelectric and magnetostrictive effects, indicating that the Fe dots/BaTiO3 hybrid structure provides a promising basis for controlling micromagnetic domain structures using electric voltage.
High-pressure and high temperature synthesis and magnetic characterization of niobio-cuprate Nb0.9Sr2YCu2.1O7.9
Authors: Balamurugan S. , Awana V. P. S. , Takayama-Muromachi E.
Published: May 2007

We have successfully synthesized a 1212-type niobio-cuprate with an ideal formula of NbSr2YCu2O8 by high-pressure and high temperature method. The phase-pure sample was obtained by Nb-poor Cu-rich starting composition, Nb0.9Sr2YCu2.1O7.9, at 6GPa and 1450°C for 2h. The 1212-type niobio-cuprate has tetragonal lattices of a=3.853(1)Å and c=11.547(1)Å (space group P4∕mmm), isostructural to Ru–1212Y phase. From magnetic measurements, it was found that superconductivity and weak ferromagnetism coexisted below ∼17K in the Nb0.9Sr2YCu2.1O7.9 sample, although the superconducting volume fraction is still very small.
Effects of bismuth substitution on Tb3−xBixFe5O12
Authors: Park Il. Jin , Kim Chul Sung
Published: May 2007

The crystallographic and magnetic properties of Tb3−xBixFe5O12 (x=0.5, 0.75, 1.0, and 1.25) powders were studied using x-ray diffraction, vibrating sample magnetometer, and Mössbauer spectroscopy. The crystal structure of the samples is determined to be normal cubic structure Ia3d by Rietveld refinement. The temperature dependence of magnetization with increasing bismuth concentration from x=0.5 to x=1.25 showed the decrease of compensation temperature from 177to107K. Moreover, the field-cooled magnetizations of all samples show negative magnetization below the compensation temperature. We suggest that the negative magnetization is related to the local anisotropy by the strong covalent interaction between bismuth and iron. The isomer shifts obtained from Mössbauer spectra at room temperature of the (16a) and (24d) sites are about 0.26 and 0.04mm∕s, respectively, for all samples, which means that the irons at the (24d) site have a strong covalent interaction with bismuth. The Néel temperature increased from 616to655K with increase of bismuth concentration from x=0.5 to x=1.25. Also, the saturation magnetization at room temperature increases linearly with increase of bismuth concentration. These behaviors can be explained by strong exchange interaction between a and d sublattices with increase of bismuth concentration.
Self-pinning: Dominant coercivity mechanism in exchange-coupled permanent/composite magnets
Authors: Zhao G. P. , Wang X. L. , Yang Chun , Xie L. H. , Zhou G.
Published: May 2007

Our micromagnetic calculation demonstrates that the dominant coercivity mechanism is self-pinning in most exchange-coupled permanent and composite magnets. Such a pinning is attributed to the change of the intrinsic parameters associated with the phase change at the interface. From this self-pinning some more specific formulas on pinning field can be derived. In particular, for sufficiently large soft grains/defects, the pinning field can be expressed as HP=αHK, where HK=2k∕MS is the anisotropy field and α depends on the material parameters and micromagnetic structures. For an exchange-coupled Nd2Fe14B–αFe system with abrupt change of parameters in the interface, α≈0.1. Reducing the size of the soft grain will increase the coercivity, while the smooth change of the parameters in the interface will lead to a reduction in the coercivity. Comparison with experimental data justifies our calculation.