bluuebunny/crossref_metadata_2025 huggingface dataset:
Intelligibility of Modified Speech for Young Listeners With Normal and Impaired Hearing
Authors: Uchanski Rosalie M. , Geers Ann E. , Protopapas Athanassios
Published: April 2006

Exposure to modified speech has been shown to benefit children with languagelearning impairments with respect to their language skills (M. M. Merzenich et al., 1998; P. Tallal et al., 1996). In the study by Tallal and colleagues, the speech modification consisted of both slowing down and amplifying fast, transitional elements of speech. In this study, we examined whether the benefits of modified speech could be extended to provide intelligibility improvements for children with severe-to-profound hearing impairment who wear sensory aids. In addition, the separate effects on intelligibility of slowing down and amplifying speech were evaluated.

Two groups of listeners were employed: 8 severe-to-profoundly hearingimpaired children and 5 children with normal hearing. Four speech-processing conditions were tested: (1) natural, unprocessed speech; (2) envelope-amplified speech; (3) slowed speech; and (4) both slowed and envelope-amplified speech. For each condition, three types of speech materials were used: words in sentences, isolated words, and syllable contrasts. To degrade the performance of the normal-hearing children, all testing was completed with a noise background.

Results from the hearing-impaired children showed that all varieties of modified speech yielded either equivalent or poorer intelligibility than unprocessed speech. For words in sentences and isolated words, the slowing-down of speech had no effect on intelligibility scores whereas envelope amplification, both alone and combined with slowing-down, yielded significantly lower scores. Intelligibility results from normal-hearing children listening in noise were somewhat similar to those from hearing-impaired children. For isolated words, the slowing-down of speech had no effect on intelligibility whereas envelope amplification degraded intelligibility. For both subject groups, speech processing had no statistically significant effect on syllable discrimination. In summary, without extensive exposure to the speech processing conditions, children with impaired hearing and children with normal hearing listening in noise received no intelligibility advantage from either slowed speech or envelope-amplified speech.
A Longitudinal Investigation of Reading Outcomes in Children With Language Impairments
Authors: Catts Hugh W. , Fey Marc E. , Tomblin J. Bruce , Zhang Xuyang
Published: April 2006

This investigation examined the reading outcomes of children with language impairments (LI). A large subsample of children who participated in an epidemiologic study of language impairments in kindergarten (J. B. Tomblin, N. Records, P. Buckwalter, X. Zhang, E. Smith, & M. O'Brien, 1997) was followed into second and fourth grades. Participants' language, reading, and nonverbal cognitive abilities were assessed. Results indicated that children with LI in kindergarten were at a high risk for reading disabilities in second and fourth grades. This risk was higher for children with a nonspecific language impairment (nonverbal and language deficits) than for those with a specific language impairment (deficits in language alone). Children with LI in kindergarten who had improved in spoken language abilities by second and fourth grades had better reading outcomes than those with persistent language impairments. Also, children's literacy knowledge/experience in kindergarten and their initial reading achievement in second grade were good predictors of subsequent reading outcomes.
Across-Frequency Comparison of Temporal Speech Information by Listeners With Normal and Impaired Hearing
Authors: Healy Eric W. , Bacon Sid P.
Published: April 2006

Listeners with normal hearing (NH) and with sensorineural hearing impairment (HI) were tested on a speech-recognition task requiring across-frequency integration of temporal speech information. Listeners with NH correctly identified a majority of key words in everyday sentences when presented with a synchronous pair of speech-modulated tones at 750 and 3000 Hz. They could tolerate small amounts (12.5 ms) of across-frequency asynchrony, but performance fell as the delay between bands was increased to 100 ms. Listeners with HI performed more poorly than those with NH when presented with synchronous across-frequency information. Further, performance of listeners with HI fell as a function of asynchrony more steeply than that of their NH counterparts. These results suggest that listeners with HI have particular difficulty comparing and effectively processing temporal speech information at different frequencies. The increased influence of asynchrony indicates that these listeners are especially hindered by slight disruptions in across-frequency information, which implies a less robust comparison mechanism. The results could not be attributed to differences in signal or sensation level, or in listener age, but instead appear to be related to the degree of hearing loss. This across-frequency deficit is unlikely to be attributed to known processing difficulties and may exist in addition to other known disruptions.
Surface Forms and Grammatical Functions
Authors: Leonard Laurence B. , Deevy Patricia , Miller Carol A. , Rauf Leila , Charest Monique , Kurtz Robert
Published: April 2006

Children with specific language impairment (SLI) use past tense -
ed
in fewer obligatory contexts than younger normally developing children matched for mean length of utterance (MLU). In this study, the use of passive participle -
ed
(e.g.,
kissed
in
The frog got kissed by the kitty
) as well as past tense -
ed
was examined in children with SLI, normally developing children matched for age (ND-A), and normally developing children matched for MLU (ND-MLU). The children with SLI used both past tense -
ed
and passive participle -
ed
in fewer obligatory contexts than both the ND-A and the ND-MLU children. Only the children with SLI had greater difficulty with past tense -
ed
than with passive participle -
ed
. The pattern of findings indicates that the surface properties of -
ed
cannot adequately account for the past tense -
ed
difficulty shown by the children with SLI. However, the fact that the children with SLI were less consistent than the ND-MLU children in using passive participle -
ed
suggests that either the surface properties of -
ed
are responsible for a portion of the difficulty or these children have a separate, non-tenserelated deficit in the area of verb morphology.
Delayed Predictive Accuracy of Narrative Recall After Traumatic Brain Injury
Authors: Kennedy Mary R. T. , Nawrocki Michael D.
Published: April 2006

Fifteen adults with traumatic brain injury (TBI) and 15 adults without brain injury listened to narratives, made delayed predictions of recall, and took a delayed recall test. Narrative questions differed by salience (main ideas, details) and explicitness (implied, stated) (R. H. Brookshire & L. E. Nicholas, 1993). TBI survivors recalled less than control participants regardless of question type. All participants recalled main ideas and implied information with greater accuracy than details and stated information. Predictive accuracy for recalling stated information was strong regardless of group. Participants were unable to predict recall for implied information. The materials-appropriate-processing (MAP) hypothesis proposes that predictive accuracy is biased by text type (i.e., predictive accuracy for recalling main ideas should be higher than for details when learning narratives). However, there were no differences in predictive accuracy for recalling main ideas and details, with both groups predicting recall modestly well. Controlling for explicitness appears to be an important variable for future metamemory text studies.
Parent-Reported Language Skills in Relation to Otitis Media During the First 3 Years of Life
Authors: Feldman Heidi M. , Dollaghan Christine A. , Campbell Thomas F. , Colborn D. Kathleen , Janosky Janine , Kurs-Lasky Marcia , Rockette Howard E. , Dale Philip S. , Paradise Jack L.
Published: April 2006

As part of a larger study of the potential impact of early-life otitis media (OM) on speech, language, cognition, and behavior, we studied the degree of association between parent-reported language scores at ages 1, 2, and 3 years and the cumulative duration of middle-ear effusion (MEE) during the first 3 years of life in a demographically diverse sample of 621 children. We estimated the cumulative percentage of days with MEE from prospective monthly observations of middle-ear status and interpolations for periods between visits. For each child, parents completed the appropriate inventory of the MacArthur Communicative Development Inventories (CDI; L. Fenson et al., 1993) at ages 1, 2, and 3 years. We also evaluated the contribution of maternal education, as a proxy for socioeconomic-status, to scores on the parent reports.

Scores on the new CDI-III (B. Oliver et al., in press) varied positively with sociodemographic variables and were significantly correlated with scores from the CDI used when the children were younger. Unadjusted correlations between scores at ages 1 and 2 years and the percentages of days with MEE in the respective antecedent periods were statistically nonsignificant or of questionable clinical importance. The correlations between parent-reported scores at age 3 years and children's cumulative percentage of days with MEE in Years 1, 2, and 3 combined ranged from –.187 to –.248 (allpvalues < .001). The percentage of days with MEE and maternal education each contributed independently to scores at age 3 years. In the light of other findings from the larger study, we think it likely that the negative associations between language measures and MEE reflect confounding factors that contribute, on the one hand, to the duration of OM in young children and, on the other hand, to slow development of their language skills.
Generalizability Theory II
Authors: O'Brian Sue , Packman Ann , Onslow Mark , O'Brian Nigel
Published: April 2006

Generalizability theory has been recommended as the most comprehensive method for assessing the reliability of observational data. It provides a framework for calculating the various sources of measurement error and allows further design of measurements for a particular purpose. This paper gives a practical illustration of how this method may be used in the analysis of observational data. We use the ratings of 15 unsophisticated raters using the 9-point speech naturalness scale of R. R. Martin, S. K. Haroldson, and K. A. Triden (1984) to evaluate the speech of adults before and after treatment for stuttering. We calculate various sources of measurement error and use these to estimate the minimum number of raters and ratings per rater for a reliable result. For posttreatment data, the average of three independent raters, and for pretreatment data, the average of five independent raters should give a result within one scale point of the hypothetical true score for the speaker in at least 80% of samples. The example illustrates the advantages of using this method of analysis.
Auditory Serial Position Effects in Story Retelling for Non-Brain-Injured Participants and Persons With Aphasia
Authors: Brodsky Martin B. , McNeil Malcolm R. , Doyle Patrick J. , Fossett Tepanata R. D. , Timm Neil H. , Park Grace H.
Published: April 2006

Using story retelling as an index of language ability, it is difficult to disambiguate comprehension and memory deficits. Collecting data on the serial position effect (SPE), however, illuminates the memory component. This study examined the SPE of the percentage of information units (%IU) produced in the connected speech samples of adults with aphasia and age-matched, non-brain-injured (NBI) participants. The NBI participants produced significantly more direct and alternate IUs than participants with aphasia. Significant age and gender differences were found in subsamples of the NBI controls, with younger and female participants generating significantly more direct IUs than male and older NBI participants. Alternate IU productions did not generate an SPE from any group. There was a significant linear increase from the initial (primacy) to the final (recency) portion of the recalled alternate IUs for both the NBI group and the group of participants with aphasia.

Results provide evidence that individuals with aphasia recall discourse length information using similar memory functions as the nonimpaired population, though at a reduced level of efficiency or quantity. A quadratic model is suggested for the recall of information directly recalled from discourse-length language material.
Respiratory and Laryngeal Responses to an Oral Air Pressure Bleed During Speech
Authors: Huber Jessica E. , Stathopoulos Elaine T.
Published: April 2006

Researchers have hypothesized that the respiratory and laryngeal speech subsystems would respond to an air pressure bleed, but these responses have not been empirically studied. The present study examined the nature of the responses of the respiratory and laryngeal subsystems to an air pressure bleed in order to provide information relevant to the nature of motor control for speech. Participants produced a syllable train consisting of 7 syllables of [pα] 10 times with and without an air pressure bleed in place. Acoustic, aerodynamic, and respiratory kinematic data were collected. In the bleed condition, peak intraoral air pressure and average oral airflow during the [α] were lower, lung and rib cage volume excursions were longer, and rib cage volume terminations were more negative. This study provides empirical data demonstrating a clear interaction among the speech subsystems. Both active and passive mechanisms are suggested by the subsystems' responses.
Temperamental Characteristics of Young Children Who Stutter
Authors: Anderson Julie D. , Pellowski Mark W. , Conture Edward G. , Kelly Ellen M.
Published: April 2006

The purpose of this investigation was to assess the temperamental characteristics of children who do (CWS) and do not (CWNS) stutter using a norm-referenced parent-report questionnaire. Participants were 31 CWS and 31 CWNS between the ages of 3;0 (years;months) and 5;4 (CWS: mean age=48.03 months; CWNS: mean age=48.58 months). The CWS were matched by age (±4 months), gender, and race to the CWNS. All participants had speech, language, and hearing development within normal limits, with the obvious exception of stuttering for CWS. Children's temperamental characteristics were determined using the Behavioral Style Questionnaire (BSQ; S. C. McDevitt & W. B. Carey, 1978), which was completed by each child's parents. Results, based on parent responses to the BSQ, indicated that CWS are more apt, when compared to CWNS, to exhibit temperamental profiles consistent with hypervigilance (i.e., less distractibility), nonadaptability to change, and irregular biological functions. Findings suggest that some temperamental characteristics differentiate CWS from CWNS and could conceivably contribute to the exacerbation, as well as maintenance, of their stuttering.
Phonological Representations in Children With SLI
Authors: Maillart Christelle , Schelstraete Marie-Anne , Hupet Michel
Published: April 2006

The present research examined the quality of the phonological representations of French children with specific language impairment (SLI) and those with normal language development (NLD). Twenty-five children with SLI and 50 children with NLD matched on lexical age level participated in an auditory lexical decision task. The observations gathered in our study can be summarized as follows. First, children with a higher receptive lexical level performed better, and this was true both for children with NLD and children with SLI. Second, both children with NLD and those with SLI were more likely to reject pseudowords resulting from a modification affecting the number of syllables of a word than pseudowords resulting from a slight modification with the number of syllables unchanged. This difference, however, was greater for the children with SLI, who appeared to have much difficulty rejecting pseudowords resulting from slight modifications. Finally, the performance of children with SLI was particularly poor when presented with pseudowords resulting from a slight modification at the beginning or the end of a word. These findings are interpreted as supporting the hypothesis of an underspecification of phonological representations in children with SLI.
Hidden Language Impairments in Children
Authors: Nation Kate , Clarke Paula , Marshall Catherine M. , Durand Marianne
Published: April 2006

This study investigates the oral language skills of 8-year-old children with impaired reading comprehension. Despite fluent and accurate reading and normal nonverbal ability, these children are poor at understanding what they have read. Tasks tapping 3 domains of oral language, namely phonology, semantics, and morphosyntax, were administered, along with measures that reflect an interaction of language domains that we refer to as
broader language skills
. Relative to control children matched for age and decoding ability, poor comprehenders were impaired across all measures except those tapping phonological skills. In addition to low oral language ability characterizing the group as a whole, some individuals had marked language impairments; it is argued that a substantial minority can be classified as having specific language impairment. However, none of the children had been previously recognized as having a language or reading impairment. These findings demonstrate that serious reading and language impairments are not always obvious in children who have good phonological ability and appear, superficially at least, to read well.
The Emerging Lexicon of Children With Phonological Delays
Authors: Storkel Holly L.
Published: April 2006

The effects of phonotactic constraints (i.e., the status of a sound as correctly or incorrectly articulated) and phonotactic probability (i.e., the likelihood of a sound sequence) on lexical acquisition have been investigated independently. This study investigated the interactive influence of phonotactic constraints and phonotactic probability on lexical acquisition in 3 groups of children: children with functional phonological delays (PD), phonology-matched, younger, typically developing children (PM), and age-/vocabulary-matched typically developing peers (AVM). Sixty-eight children participated in a multitrial word-learning task involving nonwords varying in phonotactic constraints (IN vs. OUT) and phonotactic probability (common vs. rare). Correct and error responses were analyzed. Results indicated that OUT sound sequences were learned more rapidly than IN sound sequences. This suggests that OUT sounds may be salient because they represent only a small subset of the child's sound system. The effect of phonotactic probability varied across groups: Children with PD showed a common sound sequence disadvantage, younger PM children showed a common sound sequence advantage, and AVM children showed no effect. Moreover, error analyses indicated that children with PD had particular difficulty creating lexical representations and associations between lexical and semantic representations when learning common sound sequences. Children with PD may rely more heavily on lexical representations to learn new words or may have difficulty learning common sound sequences because of the high degree of similarity between these sequences and other known words. Finally, the effect of phonotactic probability was consistent across IN and OUT sound sequences, suggesting that the lexical representation of both correctly articulated and misarticulated words is based on the adult-target pronunciation.
Tense and Agreement in the Speech of Children With Specific Language Impairment
Authors: Leonard Laurence B. , Camarata Stephen M. , Brown Barbara , Camarata Mary N.
Published: April 2006

Thirty-one children with specific language impairment participated in 48 intervention sessions designed to assist them in the use of 3rd-person singular -
s
or auxiliary
is/are/was
. Gains in the use of these target forms were significantly greater than gains on developmentally comparable morphemes serving as control forms. Untreated verb forms that mark both tense and agreement showed greater change during the intervention period than did past -
ed
. The findings suggest that by gaining skill in the use of morphemes that mark both tense and agreement, the children were able to identify and acquire other morphemes in the language that mark both of these features. This increase in sensitivity did not appear to apply to forms in the language that express tense only.
The Effects of Direct Instruction on the Single-Word Reading Skills of Children Who Require Augmentative and Alternative Communication
Authors: Fallon Karen A. , Light Janice , McNaughton David , Drager Kathryn , Hammer Carol
Published: April 2006

Current literature suggests a lack of empirically validated strategies for teaching reading skills to children who use augmentative and alternative communication (AAC). The current study implemented a single-subject, multiple-probe-across-subjects design to investigate the effects of direct instruction in single-word reading on the performance of students who use AAC. The instructional program targeted the reading skills of 5 participants who had severe speech impairments and ranged in age from 9 to 14 years old. All 5 participants reached criterion for matching targeted written words to corresponding pictures. Three of the 5 participants demonstrated generalization of reading skills to novel-word reading, and 4 of the 5 generalized reading skills to book contexts. Implications and directions for future research are discussed.
Bolus Location Associated With Videofluoroscopic and Respirodeglutometric Events
Authors: Perlman Adrienne L. , He Xuming , Barkmeier Joseph , Leer Eva Van
Published: April 2006

The purpose of the present investigation was to determine the relation between specific events observed with simultaneous videofluoroscopy and respirodeglutometry. The order of occurrence was determined for each of 31 events (18 videofluoroscopic, 13 respirodeglutometric). Using 1 video frame (33.3 ms) as the maximum distance allowed between the average times of 2 events in the same cluster, 8 potential clusters were identified, 3 of which were statistically confirmed based on 90% confidence intervals on the mean time distances between events. Confirmed clusters included the time of (a) complete velar descent and the onset of the small noninspiratory flow (SNIF), (b) full separation of the base of the tongue from the pharyngeal wall and SNIF nadir, complete upper esophageal sphincter closure, and SNIF nadir, and (c) onset of epiglottic return and apnea offset. The onset of respiratory flow occurred within 13 ms after the onset of epiglottic return. Additionally, the percentage of swallows during which the bolus head or tail was located at each of 6 locations was determined for 20 of these events (10 videofluoroscopic, 10 respirodeglutometric). The 6 locations of interest included the oral cavity, base of tongue, valleculae, pyriform sinuses, upper esophageal sphincter, and the esophagus. Lastly, of the 72 swallows performed by these healthy, young adults, 65 (90.3%) were preceded by expiration, and all (100%) were followed by expiration.
Preschoolers Learning Hmong and English
Authors: Kan Pui Fong , Kohnert Kathryn
Published: April 2006

Picture naming and picture identification tasks were used to investigate lexical-semantic skills in young children learning Hmong as a first language (L1) and English as a second language (L2). A total of 19 children, ages 3;4 (years;months)-5;2, participated in this study. Performance on lexical tasks was analyzed as a function of development (older and younger participants), language (Hmong and English), modality (receptive and expressive skills), and the nature of total or "composite" vocabulary scores (translation equivalents or singles, reflecting comparable forms in both languages as compared to concepts lexicalized into only 1 language). Older participants outperformed younger participants in English, but not Hmong, indicating a relative stabilization of L1 skills, alongside more robust growth in L2. The difference between expressive and receptive performance was also much greater in Hmong than English. Composite scores were always greater than single language scores and the proportion of translation equivalents increased with age.
Characteristics of the Lax Vowel Space in Dysarthria
Authors: Tjaden Kris , Rivera Deanna , Wilding Gregory , Turner Greg S.
Published: April 2006

It has been hypothesized that lax vowels may be relatively unaffected by dysarthria, owing to the reduced vocal tract shapes required for these phonetic events (G. S. Turner, K. Tjaden, & G. Weismer, 1995). It also has been suggested that lax vowels may be especially susceptible to speech mode effects (M. A. Picheny, N. I. Durlach, & L. D. Braida, 1986). Studies evaluating these suggestions are lacking, however. The present study was an initial investigation of the vowel space area formed by the lax vowels /
i
/, /ε/, and /υ/, occurring in a passage read in
habitual, fast
, and
slow
conditions by speakers with amyotrophic lateral sclerosis (ALS), speakers with Parkinson's disease (PD), and healthy controls. Vowel space areas for speakers with ALS but not speakers with PD differed from those for the appropriate control group. Thus, only the results for the PD group support the hypothesis that lax vowel space areas for speakers with dysarthria should be similar to those for neurologically normal talkers. Compared with the
habitual
condition, rate reduction was associated with an expanded vowel space area for all of the healthy talkers but for only about half of the speakers with dysarthria. In addition, about half of the speakers in each group demonstrated a reduced vowel space area for the
fast
condition relative to the
habitual
condition, although the statistical analyses indicated no difference in vowel space areas for the
fast
and
habitual
conditions. The current study therefore provides only limited support for the idea that lax vowels are highly susceptible to speech mode effects, at least when the speech modes under consideration include faster-than-normal and slower-than normal rates. Clinical implications are discussed.
Phonological Awareness in Deaf Children Who Use Cochlear Implants
Authors: James Deborah , Rajput Kaukab , Brown Tracey , Sirimanna Tony , Brinton Julie , Goswami Usha
Published: April 2006

A short-term longitudinal study was conducted to investigate possible benefits of cochlear implant (CI) use on the development of phonological awareness in deaf children. Nineteen CI users were tested on 2 occasions. Two groups of deaf children using hearing aids were tested once: 11 profoundly deaf and 10 severely deaf children. A battery of tests was designed to investigate syllable, rhyme, and phoneme awareness. Syllable awareness in the CI users was equivalent to that of the severely deaf group, and rhyme and phoneme awareness was similar to that of the profoundly deaf children using hearing aids. CI use affords some benefit to the development of phonological awareness. The results from this study indicate that this enhancement is first observable at the syllable level.
Free-energy analysis of solubilization in micelle
Authors: Matubayasi Nobuyuki , Liang Kuo Kan , Nakahara Masaru
Published: April 2006

A statistical-mechanical treatment of the solubilization in micelle is presented in combination with molecular simulation. The micellar solution is viewed as an inhomogeneous and partially finite, mixed solvent system, and the method of energy representation is employed to evaluate the free-energy change for insertion of a solute into the micelle inside with a realistic set of potential functions. Methane, benzene, and ethylbenzene are adopted as model hydrophobic solutes to analyze the solubilization in sodium dodecyl sulfate micelle. It is shown that these solutes are more favorably located within the micelle than in bulk water and that the affinity to the micelle inside is stronger for benzene and ethylbenzene than for methane. The micellar system is then divided into the hydrophobic core, the head-group region in contact with water, and the aqueous region outside the micelle to assess the relative importance of each region in the solubilization. In support of the pseudophase model, the aqueous region is found to be unimportant to determine the extent of solubilization. The contribution from the hydrophobic-core region is shown to be dominant for benzene and ethylbenzene, while an appreciable contribution from the head-group region is observed for methane. The methodology presented is not restricted to the binding of a molecule to micelle, and will be useful in treating the binding to such nanoscale structures as protein and membrane.
Comprehensive theoretical studies on the low-lying electronic states of NiF, NiCl, NiBr, and NiI
Authors: Zou Wenli , Liu Wenjian
Published: April 2006

The low-lying electronic states of the nickel monohalides, i.e., NiF, NiCl, NiBr, and NiI, are investigated by using multireference second-order perturbation theory with relativistic effects taken into account. For the energetically lowest 11 Λ-S states and 26 Ω states thereinto, the potential energy curves and corresponding spectroscopic constants (vertical and adiabatic excitation energies, equilibrium bond lengths, vibrational frequencies, and rotational constants) are reported. The calculated results are grossly in very good agreement with those solid experimental data. In particular, the ground state of NiI is shown to be different from those of NiF, NiCl, and NiBr, being in line with the recent experimental observation. Detailed analyses are provided on those states that either have not been assigned or have been incorrectly assigned by previous experiments.
Rotational ℓ-type resonance in BeH2, BeD2, and MgH2
Authors: Shayesteh Alireza , Bernath Peter F.
Published: April 2006

In two previous papers on the infrared emission spectra of gaseous BeH2, BeD2, and MgH2 molecules, we reported rotational analyses of the antisymmetric stretching fundamental band and several hot bands. The problems in the ℓ-type resonance fits of BeH2 and MgH2 have now been resolved, and the results are reported in this Note.
Spin transfer stimulated microwave emission in MgO magnetic tunnel junctions
Authors: Nazarov Alexey V. , Olson Heidi M. , Cho Haeseok , Nikolaev Konstantin , Gao Zheng , Stokes Scott , Pant Bharat B.
Published: April 2006

Measurements of noise properties of MgO-based magnetic tunnel junctions were performed in the frequency range from 100MHzto18GHz. A pronounced narrow peak at the frequency of around 7GHz with a full width at half-maximum as low as 21MHz has been observed. The peak amplitude and 1∕f noise have a threshold dependence on the dc bias current. The narrow peak is present only at one current polarity for an antiparallel orientation of the magnetic layers adjacent to the barrier, which is consistent with spin-momentum transfer theoretical predictions.
Optically directed molecular transport and 3D isoelectric positioning of amphoteric biomolecules
Authors: Hafeman Dean G. , Harkins James B. , Witkowski Charles E. , Lewis Nathan S. , Warmack Robert J. , Brown Gilbert M. , Thundat Thomas
Published: April 2006

We demonstrate the formation of charged molecular packets and their transport within optically created electrical force-field traps in a pH-buffered electrolyte. We call this process photoelectrophoretic localization and transport (PELT). The electrolyte is in contact with a photoconductive semiconductor electrode and a counterelectrode that are connected through an external circuit. A light beam directed to coordinates on the photoconductive electrode surface produces a photocurrent within the circuit and electrolyte. Within the electrolyte, the photocurrent creates localized force-field traps centered at the illuminated coordinates. Charged molecules, including polypeptides and proteins, electrophoretically accumulate into the traps and subsequently can be transported in the electrolyte by moving the traps over the photoconductive electrode in response to movement of the light beam. The molecules in a single trap can be divided into aliquots, and the aliquots can be directed along multiple routes simultaneously by using multiple light beams. This photoelectrophoretic transport of charged molecules by PELT resembles the electrostatic transport of electrons within force-field wells of solid-state charge-coupled devices. The molecules, however, travel in a liquid electrolyte rather than a solid. Furthermore, we have used PELT to position amphoteric biomolecules in three dimensions. A 3D pH gradient was created in an electrolyte medium by controlling the illumination position on a photoconductive anode where protons were generated electrolytically. Photoelectrophoretic transport of amphoteric molecules through the pH gradient resulted in accumulation of the molecules at their apparent 3D isoelectric coordinates in the medium.
Vacuolar protein sorting receptor in Schizosaccharomyces pombe
Authors: Iwaki Tomoko , Hosomi Akira , Tokudomi Sanae , Kusunoki Yoko , Fujita Yasuko , Giga-Hama Yuko , Tanaka Naotaka , Takegawa Kaoru
Published: April 2006

The mechanism by which soluble proteins, such as carboxypeptidase Y, reach the vacuole inSaccharomyces cerevisiaeis very similar to the mechanism of lysosomal protein sorting in mammalian cells. Vps10p is a receptor for transport of soluble vacuolar proteins inS. cerevisiae.vps10+, a gene encoding a homologue ofS. cerevisiae PEP1/VPS10, has been identified and deleted from the fission yeastSchizosaccharomyces pombe. Deletion of thevps10+gene resulted in missorting and secretion ofSch. pombevacuolar carboxypeptidase Cpy1p, indicating that it is required for targeting Cpy1p to the vacuole.Sch. pombeVps10p (SpVps10p) is a type I transmembrane protein and its C-terminal cytoplasmic tail domain is essential for Cpy1p transport to the vacuole. Cells expressing green fluorescent protein-tagged SpVps10p produced a punctate pattern of fluorescence, indicating that SpVps10p was largely localized in the Golgi compartment. In addition,Sch. pombe vps26+,vps29+andvps35+, encoding homologues of theS. cerevisiaeretromer componentsVPS26,VPS29andVPS35, were identified and deleted. Fluorescence microscopy demonstrated that SpVps10p mislocalized to the vacuolar membrane in these mutants. These results indicate that thevps26+,vps29+andvps35+gene products are required for retrograde transport of SpVps10p from the prevacuolar compartment back to the Golgi inSch. pombecells.
YopM of Yersinia enterocolitica specifically interacts with α1-antitrypsin without affecting the anti-protease activity
Authors: Heusipp Gerhard , Spekker Katrin , Brast Sabine , Fälker Stefan , Schmidt M. Alexander
Published: April 2006

It was previously shown thatα1-antitrypsin (AAT) interacts with the type III secreted (T3S) EspB and EspD proteins of enteropathogenicEscherichia coli(EPEC), resulting in reduced functionality of the proteins. To determine if AAT is also able to interact with T3S proteins of other pathogens, the binding of AAT to Yop proteins ofYersinia enterocoliticawas analysed. AAT did not interact with YopB or YopD, which have functions in type III translocation similar to EspB and EspD in EPEC, but specifically interacts with YopM, a member of the leucine-rich repeat (LRR) family of proteins, in overlay and pull-down assays. To determine regions of YopM involved in AAT binding, various N- and C-terminally truncated versions of YopM were recombinantly expressed, and their ability to interact with AAT analysed. All versions tested were able to bind AAT, indicating that at least eight LRR of YopM are sufficient for AAT interaction. The main physiological role of AAT is to inhibit neutrophil elastase; however, elastase was efficiently inhibited by AAT in the presence and absence of YopM, indicating that YopM does not interfere with the anti-protease inhibition activity of AAT, and that the domain of AAT interacting with YopM is not identical to AAT's protease interaction domain. Furthermore, it was shown that elastase efficiently degrades YopM and other Yop proteins. The data suggest that AAT has additional functions in the host response against bacterial infections that are not related to its anti-protease activity.
Unravelling the role of the ToxR-like transcriptional regulator WmpR in the marine antifouling bacterium Pseudoalteromonas tunicata
Authors: Stelzer Sacha , Egan Suhelen , Larsen Martin R. , Bartlett Douglas H. , Kjelleberg Staffan
Published: April 2006

The dark-green-pigmented marine bacterium Pseudoalteromonas tunicata produces several target-specific compounds that act against a range of common fouling organisms, including bacteria, fungi, protozoa, invertebrate larvae and algal spores. The ToxR-like regulator WmpR has previously been shown to regulate expression of bioactive compounds, type IV pili and biofilm formation phenotypes which all appear at the onset of stationary phase. In this study a comparison of survival under starvation or stress between the wild-type P. tunicata strain and a wmpR mutant (D2W2) does not suggest a role for WmpR in regulating starvation- and stress-resistant phenotypes such as those that may be required in stationary phase. Both proteomic [2-dimensional PAGE (2D-PAGE)] and transcriptomic (RNA arbitrarily primed PCR) studies were used to discover members of the WmpR regulon. 2D-PAGE identified 11 proteins that were differentially expressed by WmpR. Peptide sequence data were obtained for six of these proteins and identified using the draft P. tunicata genome as being involved in protein synthesis, amino acid transamination and ubiquinone biosynthesis, as well as hypothetical proteins. The transcriptomic analysis identified three genes significantly up-regulated by WmpR, including a TonB-dependent outer-membrane protein, a non-ribosomal peptide synthetase and a hypothetical protein. Under iron-limitation the wild-type showed greater survival than D2W2, indicating the importance of WmpR under these conditions. Results from these studies show that WmpR controls the expression of genes encoding proteins involved in iron acquisition and uptake, amino acid metabolism and ubiquinone biosynthesis in addition to a number of proteins with as yet unknown functions.
Intraperitoneal fluid therapy: an alternative to intravenous treatment in a patient with limited vascular access
Authors: Åsheim P. , Uggen P. E. , Aasarød K. , Aadahl P.
Published: April 2006

We describe a 58‐year‐old female with Crohn's disease and short bowel syndrome after repeated intestinal resections, with only 90 cm of small intestine left. She had been dependent on vascular access for total parenteral nutrition for 16 years. Due to intravascular complications after numerous long‐term central venous catheters, her vascular accessibility became limited. During the course of a year she was fed enterally through a gastrostomy, but required supplementary fluid therapy through peripheral venous route. Because of extremely limited venous access, we decided to implant an intraperitoneal catheter for administration of crystalloid fluid. The first intraperitoneal catheter had to be removed because of a postoperative infection, but after antibiotic treatment, a second intraperitoneal catheter was implanted without complications, through which the patient is now fully provided with crystalloid fluid (Ringer's acetate). Abdominal ultrasound examination shows good absorption of the fluid, and for the first time in 16 years the patient does not need intravascular access. We suggest that intraperitoneal administration of fluid may be an alternative for patients with limited vascular access.
A comparison of oral health related quality of life between complete and partial removable denture‐wearing older adults in Korea
Authors: BAE K. H. , KIM C. , PAIK D. I. , KIM J. B.
Published: April 2006

summary  The purpose of this study was to compare the oral health related quality of life (OHRQoL) between older Korean adults with complete and partial removable dentures using oral health impact profile (OHIP). A pool of 4250 Korean older adults was identified by random stratification by area from the sample cohort of Korean National Survey of Oral Health in the year of 2000. Out of the potential pool, 445 subjects with removable partial dentures (RPDs) or complete dentures (CDs) agreed to be interviewed by telephone. Each question in the survey was about how frequently each event was experienced during the past 12 months. To analyse the association between OHIP scores and removable denture status, bivariable analysis and multiple linear regression analysis were used. RPD users showed higher scores on eight items than CD users. They were ‘breath stale’, ‘food catching’, ‘sensitive teeth’, ‘toothache’, ‘tense’, ‘unable to brush teeth’, ‘less tolerant to family members’ and ‘irritable with others’. RPD users might be associated with higher scores of functional limitation, physical pain and psychological discomfort than CD users. RPD users had slight tendency to be associated with higher OHIP‐49 score than CD users, but it was not statistically significant. The findings of the present study confirm that there is no general OHRQoL difference between RPD and CD users. But in the items and subscales of OHIP, RPD users might experience more impaired OHRQoL than CD users.
Survivorship of seedlings of false sandalwood (Myoporum platycarpum) in the chenopod rangelands grazed by sheep, kangaroos and rabbits at Whyalla, South Australia
Authors: TIVER FLEUR , KIERMEIER ANDREAS
Published: April 2006

ABSTRACT  Myoporum platycarpum R. Br. (Myoporaceae) is widely distributed through semi‐arid New South Wales, South Australia, Western Australia and Victoria, where it occurs as an upper‐storey dominant or co‐dominant tree over chenopod shrublands. Previous studies have concluded that the seedlings and juveniles of many shrubs and trees, including M. platycarpum, are selectively grazed by sheep and rabbits, which threatens their long‐term survival in rangelands. The aim of this study was to assess the survivorship of M. platycarpum seedlings grazed by sheep and rabbits in a rangeland setting. Seedlings of M. platycarpum were raised in the greenhouse and planted in the field and individually fenced to allow or prevent access by various herbivores. Over 1 year, the frequency of grazing and size of canopy was recorded. A flexible mixed model incorporating cubic smoothing splines was used to describe the relationship between change in canopy volume over time, fixed effects (exclosure type, time, rainfall and egesta weights) and random variability among plants, replicates and sites. The mixed models showed that there were no significant differences in canopy volume over time between sheep and rabbit‐proof exclosures, indicating that rabbits were not significantly affecting the seedlings, browsing only five of those available to them, of which three survived. Large herbivores (sheep and/or kangaroos) grazed un‐caged seedlings, resulting in significantly smaller canopy volumes, and higher death rates (80%). Although supplementary irrigation was applied, background losses due to desiccation in caged seedlings were up to 50%.
Vegetation structure and biodiversity along the eucalypt forest to rainforest continuum on the serpentinite soil catena in a subhumid area of Central Queensland, Australia
Authors: SPECHT RAY L. , BATIANOFF GEORGE N. , REEVES ROGER D.
Published: April 2006

Abstract  The deep lateritic earths that cap the serpentinite outcrop in the Rockhampton – Marlborough area on the Tropic of Capricorn in Central Queensland have been eroded to expose the underlying ultramafic rock. Water‐holding capacity of these nutrient‐poor soils increases in a gradient from the skeletal soils to the deep lateritic earths and results in a continuum of structural formations from open‐woodland to woodland to open‐forest. A couple of closed‐forest (rainforest) stands have developed where seepage into Marlborough Creek occurs throughout the year. Aerodynamic fluxes (frictional, thermal and evaporative) in the atmosphere as it flows over and through the vegetation influence the annual foliage growth in all strata in the continuum from skeletal soils to deep lateritic earths. The lateral growth of each plant is abraded so that the sum of the foliage projective covers of overstorey (FPCo) and understorey (FPCu) strata – that is Σ(FPCo + FPCu) – remains constant throughout the serpentinite soil catena. As more water becomes available in the soil catena, the mineral nutrient levels in overstorey leaves increase, making developing leaves more vulnerable to insect attack. Although the number of leaves produced annually on each vertical foliage shoot in the overstorey increases along the soil‐water gradient, Σ(FPCo + FPCu) remains constant in all stands. The carbon isotope ratios (a measure of stomatal resistance) and leaf specific weights (LSWs) (a measure of the proportion of structural to cytoplasmic content in a leaf) of overstorey and understorey strata, however, are constant throughout the continuum. The well‐watered rainforest pockets – where seepage occurs – form the end point of this serpentinite continuum. LSWs and carbon isotope ratios of the canopy trees are similar to those in the sheltered understorey in the eucalypt communities. A gradient of foliage attributes is observed from evergreen canopy trees (12 m) to subshrubs (2 m) in the sunlit life forms that compose the complex structure of the rainforest stands in the humid to subhumid climate of Central Queensland. As alpha diversity (number of species per hectare) is correlated with annual shoot growth per hectare, species richness along the serpentinite continuum is almost half that of nearby plant communities on medium‐nutrient soils. The one to two eucalypt species per hectare are about a tenth of the number recorded on adjacent medium‐nutrient soils.
THE CRUCIFIXION AS REALISATION OF IDENTITY: THE GIFT OF RECOGNITION AND REPRESENTATION
Authors: HENRIKSEN JAN‐OLAV
Published: April 2006

This essay approaches the complex structure of the Christian's identity from the perspective of the crucifixion of Christ. Central to this approach are the concepts of recognition and representation, which are employed to clarify presuppositions of Christian identity that can be seen as theologically and philosophically prior to the doctrinal conceptions of reconciliation and atonement. The cross can be seen as a gift only if it is simultaneously conceived of as a possibility for receiving a new identity through the recognition of God both as the other represented and representing the human on the cross. On the basis of recognition and representation, implications concerning the more doctrinal formulation of Christology, anthropology and soteriology are spelled out.
THE ESCHATOLOGICAL CHARACTER OF OUR KNOWLEDGE OF GOD
Authors: MACDONALD PAUL A.
Published: April 2006

In this essay, I show how Thomas Aquinas circumscribes epistemological questions concerning both the possibility and character of our knowledge of God within a larger eschatological framework that acknowledges the beatific vision as the ultimate good that we desire as well as the ultimate end for which we were created. Thus, knowledge of God is possible and actual on Aquinas's view because it is eternally rather than merely temporally indexed—that is, properly attributable to the blessed in heaven and only derivatively attributable to persons of faith. I further argue that interpreting Aquinas's account of faith in the light of his account of the beatific vision allows us to carve out polemical space for the theologically realist claim that there can be and in fact is objectivity in our knowledge of God, whether that knowledge comes through faith (in this life) or the beatific vision (in the next life).