bluuebunny/crossref_metadata_2025_split huggingface dataset:
Snow recurrence sets the depth of dry permafrost at high elevations in the McMurdo Dry Valleys of Antarctica
Authors: McKay Christopher P. 
Published: July 2008

AbstractDry permafrost on Earth is unique to the Antarctic and is found in the upper elevations of the McMurdo Dry Valleys. Despite its widespread presence in the Dry Valleys, the factors that control the distribution of dry permafrost and the ice-cemented ground below it are poorly understood. Here I show, by a combination of theoretical analysis and field observations, that the recurrence of snow can explain the depth of dry permafrost and the location of ice-cemented ground in Antarctica. For data from Linnaeus Terrace at 1600–1650 m elevation in Upper Wright Valley a recurrence intervals of about two years explains the presence of ground ice at 25 cm depth, under 12.5 cm of dry permafrost. Snow recurrence periods longer than 10 years would create only dry permafrost at this site. The snow gradient in University Valley resulting from the windblown snow from the polar plateau creates a corresponding gradient in the depth to ice-cemented ground. On the floor of Beacon Valley, the presence of dry permafrost without underlying ice-cemented ground indicates snow recurrence intervals of more than 10 years and implies that the ancient massive ice in this valley is not stable. Snow recurrence may also set the depth to ground ice on Mars.
Stürze und Osteoporose
Authors: Pils Katharina 
Published: July 2008

Obwohl Stürze zu den wichtigsten geriatrischen Syndromen gehören, obwohl Stürze und ihre Folgen die sechst häufigste Todesursache von Menschen älter als 65 Jahre sind, konnte noch keine ausreichende Awareness geschaffen werden. In den Guidelines der British und der American Geriatric Society wurde die Bedeutung der Entität aus Sturz- und Frakturrisiko festgelegt [1]. Dennoch ist die Umsetzung in den klinischen Alltag noch nicht selbstverständlich. Hierfür gibt es vielfältige Ursachen [2]: • Mangel an Zeit, Problematik der Hierarchisierung entsprechend der aktuellen Probleme von PatientInnen. • Mangel an Wissen und Fertigkeiten: Der Stellenwert klassischer geriatrischer Symptomenkomplexe wird in der klinischen Bewertung noch weiter hinter den klassischen Diagnosen gereiht. Geriatrische Expertise ist noch zu gering ausgeprägt. Der Focus wird häufig noch auf die singuläre Erkrankung und weniger auf die multifaktorielle Diagnostik und Therapie gelegt. • Die Koordination der unterschiedlichen Fachkompetenz zu einem umfassenden Bild fehlt häufig. • Informationsverlust an Schnittstellen zwischen verschiedenen betreuenden Settings. • Mangel an Finanzierung diagnostischer Leistungen im niedergelassenen Bereich. Gleichzeitig sind die «Stürzer» selbst häufig Verzögerer von diagnostischen und therapeutischen Maßnahmen. Einerseits werden Stürze verleugnet oder vergessen, andererseits werden die empfohlenen Maßnahmen als Einschränkung der individuellen Freiheit, als Veränderung von Gewohntem empfunden. In Cochrane Datenanalysen gibt es eindeutige Hinweise für effiziente Sturz- und Frakturpräventionsprogramme. Diese sind multifaktoriell und betreffen vor allem Bewegungskonzepte (Ausdauer- und Balancetraining – wie z.B.: Tai Chi und Adaptierung des Wohnumfeldes (Entfernung von Sturzfallen, Beleuchtung, Griffe usw.).
Antifungal‐protein production in maize (Zea mays) suspension cultures
Authors: Perri Fabio , Della Penna Serena , Rufini Francesca , Patamia Maria , Bonito Mariantonietta , Angiolella Letizia , Vitali Alberto 
Published: July 2008

The growing emergency due to the phenomenon of drug resistance to micro‐organisms has pushed forward the search for new potential drug alternatives to those already in use. Plants represent a suitable source of new antifungal molecules, as they produce a series of defensive proteins. Among them are the PRPs (pathogenesis‐related proteins), shown to be effective in vitro against human pathogens. An optimized and established cell‐suspension culture of maize (Zea mays) was shown to constitutively secrete in the medium a series of PRPs comprising the antifungal protein zeamatin (P33679) with a final yield of approx. 3 mg/litre. The in‐vitro‐produced zeamatin possessed antifungal activity towards a clinical strain of the human pathogenic yeast Candida albicans, an activity comparable with the one reported for the same protein extracted from maize seeds. Along with zeamatin, other PRPs were expressed: a 9 kDa lipid‐transfer protein, a 26 kDa xylanase inhibitor and a new antifungal protein, PR‐5. A fast, two‐step chromatographic procedure was set up allowing the complete purification of the proteins considered, making this cell line a valuable system for the production of potential antifungal agents in a reliable and easy way.
Voice Loudness and Gender Effects on Jitter and Shimmer in Healthy Adults
Authors: Brockmann Meike , Storck Claudio , Carding Paul N. , Drinnan Michael J. 
Published: July 2008

Purpose
The aim of this study was to investigate voice loudness and gender effects on jitter and shimmer in healthy young adults because previous descriptions have been inconsistent.

Method
Fifty-seven healthy adults (28 women, 29 men) aged 20–40 years were included in this cross-sectional single-cohort study. Three phonations of /a/ at soft, medium, and loud individual loudness were recorded and analyzed using PRAAT software (P. Boersma & D. Weeninkk, 2006). Voice loudness and gender effects on measured sound pressure level, fundamental frequency, jitter, and shimmer were assessed through the use of descriptive and inferential (analysis of variance) statistics.

Results
Jitter and shimmer significantly increased with decreasing voice loudness, especially in phonations below 75 dB and 80 dB. In soft and medium phonation, men were generally louder and showed significantly less shimmer. However, men had higher jitter measures when phonating softly. Gender differences in jitter and shimmer at medium loudness may be mainly linked to different habitual voice loudness levels.

Conclusion
This pragmatic study shows significant voice loudness and gender effects on perturbation. In clinical assessment, requesting phonations above 80 dB at comparable loudness between genders would enhance measurement reliability. However, voice loudness and gender effects in other age groups, in disordered voices, or when a minimal loudness is requested should be further investigated.
Effects of Training on Naïve Listeners' Judgments of the Speech Intelligibility of Children With Severe-to-Profound Hearing Loss
Authors: Ellis Lee W. , Beltyukova Svetlana A. 
Published: July 2008

PurposeThis study examined the effects of feedback training, familiarization training, and no training on naïve listeners' word identification (WI) and magnitude estimation scaling (MES) judgments of the speech intelligibility of children with severe-to-profound hearing impairments.MethodDepending on the training group, listeners received a pretest, an immediate posttest, and/or a delayed posttest.ResultsResults indicated that repeated exposure, with or without training, led to improved WI scores. Beyond the effects of repeated exposure, listeners' WI judgments of the intelligibility of speech significantly increased immediately after training in which listeners received feedback regarding the accuracy of their WI responses. The MES results were less straightforward—listeners in the feedback group perceived speech samples as less intelligible after the training, perceptions of speech intelligibility stayed almost the same for the familiarization training group, and participants in the control group perceived speech samples as more intelligible at the posttest. For the training groups that were not pretested, perceptions improved from the immediate to delayed posttest.DiscussionResults may have both theoretical and clinical significance, particularly as they relate to contrasting theories of perceptual learning and the extent to which listener characteristics may be reflected in intelligibility judgments.
Rasch Analysis of Word Identification and Magnitude Estimation Scaling Responses in Measuring Naïve Listeners' Judgments of Speech Intelligibility of Children With Severe-to-Profound Hearing Impairments
Authors: Beltyukova Svetlana A. , Stone Gregory M. , Ellis Lee W. 
Published: July 2008

Purpose
Speech intelligibility research typically relies on traditional evidence of reliability and validity. This investigation used Rasch analysis to enhance understanding of the functioning and meaning of scores obtained with 2 commonly used procedures: word identification (WI) and magnitude estimation scaling (MES).

Method
Narrative samples of children with hearing impairments were used to collect data from listeners with no previous experience listening to or judging intelligibility of speech. WI data were analyzed with the Rasch rating scale model. MES data were examined with Rasch partial credit model when individual scales were unknown, and the Rasch rating scale model was used with reported individual scales.

Results
Results indicated that both procedures have high reliability and similar discriminatory power. However, reliability and separation were lower for MES when scales were unknown. Both procedures yielded similar speech sample ordering by their difficulty. However, sampling gaps were noted as well as item misfit issues.

Conclusions
Functioning wise, both WI and MES procedures were highly reliable in measuring speech intelligibility, and measurement precision may be increased by asking participants to report their individual scales when using MES. Meaning wise, operationalization of speech intelligibility did not change when either WI or MES procedure was used. However, the sample selection procedure needs to be further refined to allow for a wider selection of stimuli.
Acoustic Correlates of Fatigue in Laryngeal Muscles: Findings for a Criterion-Based Prevention of Acquired Voice Pathologies
Authors: Boucher Victor J. 
Published: July 2008

PurposeThe objective was to identify acoustic correlates of laryngeal muscle fatigue in conditions of vocal effort.MethodIn a previous study, a technique of electromyography (EMG) served to define physiological signs of “voice fatigue” in laryngeal muscles involved in voicing. These signs correspond to spectral changes in contraction potentials. A corpus of vocalizations from the 7 participants in the EMG study was used to explore the effects of muscle fatigue on voice acoustics. Each participant produced vocalizations at regular intervals (50 in all) extending across a day (12–14 hr). The participants also produced 5 min of loud speech with peaks of 74 dBA at 1 m between each vocalization. Twenty acoustic parameters were measured using the Multi-Dimensional Voice Program (Kay Elemetrics, Lincoln Park, NJ).ResultsThe analyses showed no consistent correlations between acoustic parameters and estimates of muscle fatigue. However, in all cases, nonlinear jumps occurred in the frequency of amplitude tremor at points where fatigue estimates showed a critical shift. These jumps were robust despite changes in F0 in some individuals.ConclusionA brief rise in voice tremor can correspond to a critical change in laryngeal muscle tissues seen as a condition where continued vocal effort can increase the risk of lesions or other conditions affecting voice.
The Breadth of Coarticulatory Units in Children and Adults
Authors: Goffman Lisa , Smith Anne , Heisler Lori , Ho Michael 
Published: July 2008

PurposeTo assess, in children and adults, the breadth of coarticulatory movements associated with a single rounded vowel.MethodUpper and lower lip movements were recorded from 8 young adults and 8 children (aged 4–5 years). A single rounded versus unrounded vowel was embedded in the medial position of pairs of 7-word/7-syllable sentences.ResultsBoth children and adults produced movement trajectories associated with lip rounding that were very broad temporally (i.e., movement duration lasting 45% to 56% of the sentence). Some effects appeared to extend across the entire utterance. There were no differences between children and adults in the extent of the coarticulatory effect. However, children produced relatively variable movements associated with lip rounding.ConclusionsThese data support the hypothesis that, for young children and adults, broad chunks of output have been planned by the onset of implementation of a sentence. This implies that, based on a change in a single phoneme, the motor commands to the muscles are altered for the production of the entire sentence.
Prevalence of Stuttering in African American Preschoolers
Authors: Proctor Adele , Yairi Ehud , Duff Melissa C. , Zhang Jie 
Published: July 2008

Purpose
In this study, the authors sought to determine the prevalence of stuttering in African American (AA) 2- to 5-year-olds as compared with same-age European Americans (EAs).

Method
A total of 3,164 children participated: 2,223 AAs and 941 EAs. Data were collected using a 3-pronged approach that included investigators' individual interactions with each child, teacher identification, and parent identification of stuttering.

Results
No statistically significant difference for stuttering was found between AA and EA children. Using the investigator and teacher method of identification, the prevalence of stuttering was 2.52% for the entire sample. For both racial groups, boys exhibited a higher prevalence of stuttering than girls. Of the 3 predictors (age, race, sex) of stuttering, only sex was a significant predictor.

Conclusions
AA 2- to 5-year-olds are not overrepresented in the stuttering population for this age group. When data are combined for both racial groups, the prevalence of stuttering is 2.52%. More boys than girls stuttered in this sample of preschoolers.
Exploring Genetic and Environmental Effects in Dysphonia: A Twin Study
Authors: Simberg Susanna , Santtila Pekka , Soveri Anna , Varjonen Markus , Sala Eeva , Sandnabba N. Kenneth 
Published: July 2008

Purpose
To explore the existence of genetic effects as well as the interaction between potential genetic effects and a voice-demanding occupation on dysphonia.

Method

One thousand seven hundred and twenty-eight Finnish twins (555 male; 1,173 female) born between 1961 and 1989 completed a questionnaire concerning vocal symptoms and occupation. The zygosity determination resulted in 125 monozygotic and 108 dizygotic full twin pairs. A composite variable called
dysphonia
was formed by summing 6 vocal symptoms based on the results of a factor analysis. Twin model fitting was used to explore the contribution of genetic and environmental effects on the dysphonia variable.

Results
Individual differences in dysphonia were explained by genetic effects (35%) and nonshared environmental effects (65%). Shared environmental effects were estimated at 0%. Also, the authors found that for the participants who worked in voice-demanding occupations, the causes of dysphonia were more environmental, whereas the etiology of the symptoms was more strongly affected by genes in the participants with less voice-demanding occupations. However, this gene–environment interaction was not statistically significant.

Conclusion
Both genetic and environmental factors have an impact on the etiology of voice problems. Environmental factors, either independently or interacting with genetic factors, seem to play the key role, especially if the person has a voice-demanding occupation.
Nonnative Speech Perception Training Using Vowel Subsets: Effects of Vowels in Sets and Order of Training
Authors: Nishi Kanae , Kewley-Port Diane 
Published: July 2008

Purpose
K. Nishi and D. Kewley-Port (2007) trained Japanese listeners to perceive 9 American English monophthongs and showed that a protocol using all 9 vowels (fullset) produced better results than the one using only the 3 more difficult vowels (subset). The present study extended the target population to Koreans and examined whether protocols combining the 2 vowel sets would provide more effective training.

Method
Three groups of 5 Korean listeners were trained on American English vowels for 9 days using one of the 3 protocols: fullset only, first 3 days on subset then 6 days on fullset, or first 6 days on fullset then 3 days on subset. Participants' performance was assessed by pre- and posttraining tests, as well as by a midtraining test.

Results
(a) Fullset training was effective for Koreans as well as Japanese, (b) no advantage was found for the 2 combined protocols over the fullset-only protocol, and (c) sustained “nonimprovement” was observed for training using one of the combined protocols.

Conclusions
In using subsets for training on American English vowels, care should be taken not only in the selection of subset vowels but also in the training orders of subsets.
A Neuroimaging Study of Premotor Lateralization and Cerebellar Involvement in the Production of Phonemes and Syllables
Authors: Ghosh Satrajit S. , Tourville Jason A. , Guenther Frank H. 
Published: July 2008

Purpose
This study investigated the network of brain regions involved in overt production of vowels, monosyllables, and bisyllables to test hypotheses derived from the Directions Into Velocities of Articulators (DIVA) model of speech production (Guenther, Ghosh, & Tourville, 2006). The DIVA model predicts left lateralized activity in inferior frontal cortex when producing a single syllable or phoneme and increased cerebellar activity for consonant–vowel syllables compared with steady-state vowels.

Method
Sparse sampling functional magnetic resonance imaging (fMRI) was used to collect data from 10 right-handed speakers of American English while producing isolated monosyllables (e.g., “ba,” “oo”). Data were analyzed using both voxel-based and participant-specific anatomical region-of-interest–based techniques.

Results
Overt production of single monosyllables activated a network of brain regions, including left ventral premotor cortex, left posterior inferior frontal gyrus, bilateral supplementary motor area, sensorimotor cortex, auditory cortex, thalamus, and cerebellum. Paravermal cerebellum showed greater activity for consonant-vowel syllables compared to vowels.

Conclusions
The finding of left-lateralized premotor cortex activity supports the DIVA model prediction that this area contains cell populations representing syllable motor programs without regard for semantic content. Furthermore, the superior paravermal cerebellum is more active for consonant–vowel syllables compared with vowels, perhaps due to increased timing constraints for consonant production.
Parameters to Maximize 2f2-f1 Distortion Product Otoacoustic Emission Levels
Authors: Horn Jennifer H. , Pratt Sheila R. , Durrant John D. 
Published: July 2008

Purpose
Past research has established parameters for the 2f1-f2 distortion product otoacoustic emissions (DPOAEs) that enhance response levels (e.g., L1 – L2 = 10 dB; f2/f1 = 1.22; L1, L2 = 65, 55 dB SPL). These same parameters do not optimize 2f2-f1 DPOAEs. Therefore, this study was conducted to evaluate more completely those parameters that produce the most robust 2f2-f1 output.

Method
Input–output functions of the 2f2-f1 component were obtained from 20 normal-hearing adults (with f2 = 2000 Hz and 4000 Hz). Frequency ratios, level differences, and overall sound levels were manipulated with parameter combinations chosen to expand on information established in previous studies. The DPOAE signal-to-noise ratio (SNR), response presence, and output levels were measured.

Results
In general, mean SNRs and 2f2-f1 levels were greater, and DPOAEs were present more often for 2000 than for 4000 Hz across all parameter combinations. No single parameter combination resulted in pronounced maxima for 2f2-f1, which is consistent with past studies but is in sharp contrast to results for the more familiar 2f1-f2.

Conclusions
Overall, the results suggest that to maximize the 2f2-f1 level, lower test frequencies, low frequency ratio, essentially equal levels of primary tones, and moderate stimulus levels are best, and such parameters might be important for applying DPOAE measurement to assessment of normal and impaired auditory function.
Changes in Speech Production Associated With Alphabet Supplementation
Authors: Hustad Katherine C. , Lee Jimin 
Published: July 2008

Purpose
This study examined the effect of alphabet supplementation (AS) on temporal and spectral features of speech production in individuals with cerebral palsy and dysarthria.

Method
Twelve speakers with dysarthria contributed speech samples using habitual speech and while using AS. One hundred twenty listeners orthographically transcribed speech samples. Differences between habitual and AS speech were examined for intelligibility, rate, word duration, vowel duration, pause duration, pause frequency, vowel space, and first and second formant frequency (F1 and F2) values for corner vowels.

Results
Descriptive results showed that intelligibility was higher, rate of speech was slower, and pause duration and pause frequency were greater for AS than for habitual speech. Inferential statistics showed that vowel duration, word duration, and vowel space increased significantly for AS. Vowel space did not differ for male and female speakers; however, there was an interaction between sex and speaking condition. Changes in vowel space were accomplished by reductions in F2 for /u/. Vowel space accounted for more variability in intelligibility than rate for AS; the opposite was true for habitual speech.

Conclusion
AS is associated with temporal and spectral changes in speech production. Spectral changes associated with corner vowels appear to be more important than temporal changes.
Broadband Auditory Stream Segregation by Hearing-Impaired and Normal-Hearing Listeners
Authors: Valentine Susie , Lentz Jennifer J. 
Published: July 2008

Purpose
To investigate the effects of hearing loss on auditory stream segregation of broadband inharmonic sounds.

Method
Auditory stream segregation by listeners with normal and impaired hearing was measured for 6-component inharmonic sounds (“A” and “B”) using objective and subjective methods. Components in the A stimuli ranged between 1000 and 4000 Hz, whereas B stimuli were generated at the same frequency ratio but scaled upward in frequency relative to the A stimuli. In Experiment 1, streaming was measured by having listeners detect a delay inserted into a sequence of A and B stimuli (A_B_A_B_…) for B stimuli with different frequencies. In Experiment 2, streaming was measured using an ABA_ABA_… sequence, and the frequency of the B stimulus decreased until listeners reported that they could “no longer hear two separate streams.”

Results
Experiment 1 indicated no significant differences between groups in the size of the just detectable delay and no significant interactions between group and the scaling factor between the B and A stimuli. Experiment 2 revealed no significant differences in streaming abilities between normal-hearing and hearing-impaired groups.

Conclusions
Overall, results indicate that listeners with normal and impaired hearing have similar auditory streaming abilities for broadband inharmonic complex stimuli.