bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetation composition of a maritime salt marsh in Qatar in relation to edaphic features
Authors: Abdel‐Razik M.S. , Ismail A. M. A.
Published: April 2006

Abstract. Coverpercentage values for plant species were estimated using the line‐intercept method along two belt transects starting at the lower mangrove frontier and ending at the upper height of the salt marsh. Twelve perennial species representing five growth forms were recorded with a total cover ranging between 10 and 50 %, depending on the type of substrate. Principal components analysis of the soil data indicated an array of stands, on the basis of which four vegetation zones couldbe distinguished. The procumbent growth form predominating on the salt marsh is related to high salinity levels. The procumbent vegetation shows a zonation related to the degree of waterlogging. The rhizomatous growth form is found on sites with a low bicarbonate content and saturation percentage levels, while the undershrub‐ and stoloniferous growth forms occupy sites of low salinity level, linked with intermediate values of the other edaphic factors.
Age‐states, population structure, and seedling regeneration of Chionochloa pallens in Canterbury alpine grasslands, New Zealand
Authors: Rose Alan B. , Platt Kevin H.
Published: April 2006

Abstract. Age‐states, population structure, and seedling regeneration of the grass Chionochloa pallens were investigated in eight alpine grassland stands representing the range of canopy cover (ca. 5–75 %) and basal area (112 ‐ 3889 m2/ha‐1) in the headwaters of the Avoca catchment, Canterbury, New Zealand. In open‐canopy stands (< 50 % canopy cover, < 2000 m2/ha‐1 basal area) C. pallens individuals were clearly distinguishable. Rela‐tionshipsbetweenbasal diameter, number of tillers, height, and % crown death suggested four putative age‐states: ‘seedlings‘, ‘juvenile tussocks’, ‘mature tussocks’ and ‘senescent tussocks’. Four types of population structure were identified depending onthe proportions of seedlings and juvenile and mature tussocks. C. pallens seedlings were present in seven stands at densities ranging from 0.6 to 123.4 / m2. They were most frequent on microsites protected from frost‐heave by short herbaceous vegetation or litter, but with little competition from taller vegetation. Differences in seedling densities between stands partly reflected the proximity and abundance of seed sources and degree of protection from frost‐heave. C. pallens population structures appear to be influenced by the frequency and magnitude of geomorphic disturbances and browsing by introduced animals.
Reflections on Praxis and Nexus
Authors: Jentleson Bruce W.
Published: April 2006

It's one thing to actually work in Congress or in an administration. That's “policy work,” and we political scientists are reasonably comfortable with the ways in which our particular substantive expertises can lead us to take on policy positions. But to get involved in “politics” itself, and in a presidential campaign no less?

There is no question that it takes some adjusting. Memos by 5:00, rather than a manuscript by next year. Speeches with lots of tag lines, and not a single footnote. In-depth analyses, but in a page, please. Journalists and politicos as peer reviewers. Debate prep, not lecture notes. Meetings with interest groups, not seminars with interested students.

It's definitely a different experience. But it can be a very valuable one.

It's not basic research. But it is involvement.

It's an altogether crazy way to lead one's life. But it's exciting, and it actually can be fun.
Deep and Surface Structures in Venda Music
Authors: Blacking John
Published: April 2006

The central issue in musical theory is the problem of description. Neither musicologists nor ethnomusicologists have yet devised a system of analysis which is sufficiently powerful to explain what we can know intuitively as a result of experience in culture, namely, the essential differences between the music of Haydn and Mozart, or of the Flathead and the Sioux Indians.
Le Poète-Musicien Et La Création Poético-Musicale Au Moyen Orient
Authors: Shiloah Amnon
Published: April 2006

La création poético-musicale populaire au Proche et Moyen-Orient est sans doute intimement liée à ces individus exceptionnels qu'il convient d'appeler poètes-musiciens grâce à leur double talent. Le poètemusicien joue le rôle de divertisseur public, d'artiste créateur, de conservateur des traditions de son milieu et de commentateur des événements courants. I] est appelé sa ‘er-poète, qawwāl- celui qui dit, ou faiseur de paroles, hādī faiseur de hidā’ (genre poético-musical). D'autres titres indiquent certaines spécialisations, ou une fonction particulière tels que: zaydıyy, ou ‘antarīyy- expert dans les chants épiques relatant respectivement les actes héroïques d'Abu Zayd al-Hilali et de ‘Antar ibn Saddād, ou bien munsid- expert dans les hymnes religieux, ou naddāb-expert dans les chants funèbres. Le terme mugannī- chanteur ou musicien- qui est fréquemment employé dans la musique savante, figure rarement dans le contexte de la création populaire et comporte alors une connotation péjorative. Par conséquent le composant musical qui forme une partie intégrale et indissociable dans la création populaire, n'est nullement exprimé dans la terminologie appropriée. C'est ainsi par exemple que l'on emploie le verbe dire quand il s'agit de chanter, et le terme lahga-dialect, façon de parler particulière-pour indiquer des particularités mélodiques et stylistiques d'une localité, d'une région, ou d'un groupement ethnique donné. Cette prédominance de la parole et de ses caractèristiques accusée dans la terminologie, pourrait indiquer en quelque sorte l'assignation d'un rôle secondaire à l'élément musical dans le procédé de la création poético-musicale qui nous intéresse. Il se peut qu'il s'agisse ici d'une conception semblable à celle de la cantillation où l'objet immédiat de l'élément musical est de donner plus de portée à la parole. En outre, par rapport au grand nombre de vers et de formules de facture et de contenu divers que le poète est appelé à mémoriser, ou “inventer,” le nombre des mélodies usitées est infiniment limité. Le plus souvent l'”invention” mélodique se borne apparemment à la simple adaptation des mélodies préexistantes aux nouveaux textes. Mais nous verrons par la suite comment tout de měme le talent du poète-musicien est mis en valeur; toujours est-il que l'invention poétique a le dessus et bénéficie d'une nette prééminence. Cette invention est basée sur la technique formulaire orale qui est universelle et se retrouve partout où il y a une littérature orale.
Cobalt Recovery from Sulfate Media Applying a Liquid Membrane Containing Cyanex 302
Authors: Dimitrov K. , Rollet V. , Saboni A.
Published: April 2006

Cobalt recovery from sulfate solutions was studied by using a liquid membrane containing Cyanex 302. The influence of the pH and the concentrations of cobalt and the extractant on the metal equilibrium distribution was established. Kinetic investigations of the cobalt transfer across a liquid membrane containing Cyanex 302 were performed in a rotating film contactor. Sulfuric acid was used as a stripping agent. The results obtained show that cobalt can be successfully recovered from neutral and weakly acidic sulfate solutions. A mathematical model describing the transport of cobalt ions across the liquid membrane was proposed. The local mass transfer coefficients of cobalt ions in the aqueous phases and cobalt‐carrier complex in the organic phase were evaluated on the basis of the experimental data obtained at various conditions as well as on the proposed model.
Thermo‐Responsive Gating Characteristics of Poly(N‐isopropylacrylamide)‐Grafted Membranes
Authors: Yang M. , Chu L.‐Y. , Li Y. , Zhao X.‐J. , Song H. , Chen W.‐M.
Published: April 2006

Both hydrophilic Nylon‐6 membranes and hydrophobic poly(vinylidene fluoride) (PVDF) membranes, with a wide range of grafting yields of poly(N‐isopropylacrylamide) (PNIPAM), were prepared using the plasma‐graft pore‐filling polymerization method. The effect of the physical and chemical properties of the substrates on the thermo‐responsive gating characteristics of the PNIPAM‐grafted membranes was investigated experimentally. For both the PVDF and Nylon‐6 membranes, the grafted PNIPAM polymers were found not only on the membranes outer surface, but also on the inner surfaces of the pores throughout the entire thickness of the membrane. The thermo‐responsive gating characteristics of the PNIPAM‐grafted membranes were heavily affected by the physical and chemical properties of the porous membrane substrates. The PNIPAM‐g‐Nylon‐6 membranes exhibited a much larger thermo‐responsive gating coefficient than the PNIPAM‐g‐PVDF membranes. Furthermore, to achieve the largest thermo‐responsive gating coefficient, the corresponding optimum grafting yield of PNIPAM for the PNIPAM‐g‐Nylon‐6 membranes was also larger than that for the PNIPAM‐g‐PVDF membranes.
Effect of Oxygen on Methane Steam Reforming in a Sliding Discharge Reactor
Authors: Ouni F. , Khacef A. , Cormier J. M.
Published: April 2006

Hydrogen‐rich gas can be efficiently produced in compact plasma reformers by the conversion of a variety of hydrocarbon fuels, including natural gas and gasoline. This article describes experimental and modeling progress in plasma reforming of methane using a sliding discharge reactor (SDR). Experiments have been carried out in a compact device operating at low consumed power (1–2 kW). Previous studies of methane steam reforming using a SDR at atmospheric pressure show promising results (H2 concentration higher than 55 %). In order to study the effect of oxygen on the methane conversion and thus hydrogen production, a small amount of oxygen in the range of 7–20 % was added to the CH4‐H2O mixture. An unexpected result was that under our experimental conditions in the SDR oxygen did not have any influence on the methane conversion. Almost the totality of added oxygen is recovered intact. Moreover, part of the H2 produced was transformed into water by reaction with O2. A model describing the chemical processes based on classical thermodynamics is also proposed. The results indicate that the reactor design has to be improved in order to increase conversion and hydrogen production.
Comparison of Concentration Profiles for Boundary Layers in Absorption with Chemical Reaction Processes
Authors: Hace I.
Published: April 2006

An analysis of five different systems of absorption‐with‐chemical‐reaction in gas‐liquid reactors, commonly encountered in various industrial processes, is presented. To analyze the interphase mass transfer from gas to liquid, the rate limiting parameters and the concentrations at the gas‐liquid interface were determined on the basis of pertinent theories. The calculations presented, are based on the Whitman theory for gas and liquid phase mass transfer coefficients and Henry equilibrium constants. The necessary diffusion coefficients were calculated from existing correlations, and the corresponding chemical reaction rate constants were obtained from the literature, assuming pseudo first order chemical reaction. The process parameters required (pressure, temperature, and the gas‐liquid contact time) were within the values that occur in industrial processes. The results presented, are the concentration profiles in the boundary layers for the systems studied, calculated and graphically presented, together with the gas and liquid film thicknesses and Hatta numbers, obtained from calculations for the liquid phase mass transfer. The results may contribute to a better understanding of the absorption‐with‐chemical‐reaction processes in industrial plants, thus lowering the operational costs of these processes and alleviating the ecological problems of existing technologies.
Syntheses of Sterically Hindered Pyridinium Phenoxides as Model Compounds in Nonlinear Optics
Authors: Diemer Vincent , Chaumeil Hélène , Defoin Albert , Fort Alain , Boeglin Alex , Carré Christiane
Published: April 2006

Noncentrosymmetric molecules with a π‐conjugated system and, among them, push–pull molecules such as pyridinium phenoxide, are a promising new class of materials for applications in optoelectronics due to their nonlinear optical (NLO) properties. Modelling studies have indicated that an increase in the twist angle between the two aromatic rings leads to an enhancement of the NLO properties. In order to confirm this feature experimentally, it was necessary to prepare a series of new hindered pyridinium phenoxides. Their efficient syntheses by Suzuki cross‐coupling reactions are described herein.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Cover Picture: Macromol. Chem. Phys. 8/2006
Authors: Zhang Zhiming , Deng Junying , Sui Jing , Yu Liangming , Wan Meixiang , Wei Yen
Published: April 2006

Cover: The cover shows SEM and TEM images of microspheres of PANI prepared using Cu2O crystal, as the template, in the presence of H3PO4 and APS as a dopant and an oxidant, respectively. Further details can be found in the Full Paper by Z. Zhang, J. Deng, J. Sui, L. Yu, M. Wan,* and Y. Wei on page 763.
Atomistic Simulation of Bulk Mechanics and Local Dynamics of Amorphous Polymers
Authors: Lyulin Alexey V. , Li J. , Mulder Tim , Vorselaars Bart , Michels M.A.J.
Published: April 2006

Summary: In order to have better insight into the polymer specifics of the dynamic glass transition molecular dynamics (MD) computer simulations of three glass‐formers have been carried out: low‐molecular‐weight isopropylbenzene (iPB), brittle atactic polystyrene (PS) and tough bisphenol A polycarbonate (PC). Simulation of the uniaxial deformation of these mechanically different types of amorphous polymers shows that the mechanical experimental data could be realistically reproduced. Now the objective is to study the local orientational mobility in the non‐deformed isotropic state and to find the possible connection of the segmental dynamics with the different bulk mechanical properties. Local orientational mobility has been studied via Legendre polynomials of the second order and CONTIN analysis. Insight into local orientational dynamics on a range of length‐ and time scales is acquired. The fast transient ballistic process describing the very initial part of the relaxation has been observed for all temperatures. For all three simulated materials the slowing down of cage escape (α‐relaxation) follows mode‐coupling theory above Tg, with non‐universal, material‐specific exponents. Below Tg universal activated segmental motion has been found. At high temperature the α process is merged with the β process. The β process which corresponds to the motions within cage continues below Tg and can be described by an activation law.
Production and assembly of atomic clusters
Authors: Partridge J. G. , Reichel R. , Ayesh A. , Mackenzie D. M. A. , Brown S. A.
Published: April 2006

This paper describes the production of atomic clusters and their subsequent assembly into conducting films and wires on insulating substrates. An Ultra‐High‐Vacuum compatible Inert Gas Aggregation cluster deposition system which allows in‐situ electrical measurements to be performed on deposited cluster films has been developed. Accurate placement and dimensional control of cluster‐assembled films has been achieved in this system using soft‐landed Bi and Sb clusters and templated substrates prepared using standard optical and electron‐beam lithography. Self‐contacting cluster‐assembled films produced on planar Six Ny and SiO2 passivated Si substrates have provided a means to study conduction through percolating networks. Cluster‐assembled wires with sub‐100 nm widths have been positioned on templated Six Ny and SiO2 passivated Si substrates. The reported assembly techniques rely upon controlling cluster reflection from substrates and factors which affect the probability of cluster‐reflection are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of mycelial culture of Phellinus linteus on ethanol‐induced gastric ulcer in rats
Authors: Lee Jun Hyuk , Lee Soo Jin , Choi Yung Hyun , Chung Kyung Tae , Jeong Young Kee , Choi Byung Tae
Published: April 2006

The gastroprotective effects of a mycelial culture of Phellinus linteus (MCPL) were evaluated by determining the ulcer index, gastric mucus content, histopathological observation and histochemical properties of mucin in an ethanol‐induced ulcer model of rats. Preadministration with MCPL at doses of 20 and 60 mg/kg, showed a significant decrease of bleeding and ulcer index and alleviated the histopathological changes induced by ethanol such as hemorrhage and necrosis. Ethanol treatment decreased the gastric adhesion mucus content, but a higher level of gastric mucus persisted after preadministration of MCPL. As for the histochemical properties of mucins, marked changes were observed in both the surface and gland mucous cells in ethanol‐treated rats, but these changes were detected only in the surface mucous cells in rat preadministered with MCPL. Using conventional methods for mucins, ethanol‐treated rats revealed a decrease of neutral and acid mucin in the surface epithelium and mucous neck cells compared with normal rats. A marked decrease of BSL‐1 by lectin histochemistry was also revealed in the ethanol‐treated rats. But the MCPL preadministered rats showed similar stainabilities and lectin affinity patterns for mucins as the normal rats. These results indicate that pretreatment with MCPL provided protection of the gastric mucosa from ethanol‐induced injury by maintaining the mucus barrier in rats. Copyright © 2006 John Wiley & Sons, Ltd.
The Ginkgo biloba extract, EGb 761, fails to reduce brain infarct size in rats after transient, middle cerebral artery occlusion in conditions of unprevented, ischemia‐induced fever
Authors: de Lima Keli Carina Miltus , Schilichting Carmen Lúcia Ruiz , Junior Lourival Augusto Cestari , da Silva Flávia Munhoz , Benetoli Arcélio , Milani Humberto
Published: April 2006

There is much biochemical evidence, but very few studies in animal models of stroke in vivo, to suggest that Ginkgo biloba (EGb 761) may offer neuroprotection against regional, ischemic brain damage; additional investigations are needed to ensure future clinical trials. This study reports the effects of EGb 761 given acutely or chronically before ischemia. Rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h and the brain infarct size was assessed 24 h later. Dipyrone (100 mg/kg, i.p.) was injected 30 min before ischemia, and 2.5 and 5.5 h after ischemia, to reduce ischemia‐induced fever. EGb 761 (Tebonin®) was given acutely (200 mg/kg, p.o., 60 min before ischemia) or chronically (100 mg/kg, p.o., once daily, for 14 days before ischemia). Acute or chronic treatment with EGb 761, either alone or in combination with dipyrone, did not reduce the infarct size compared with saline alone (p > 0.05). Dipyrone failed to prevent ischemia‐induced fever during the intra‐ischemic period (p > 0.05 vs saline; p < 0.001 vs sham). In the reperfusion phase, dipyrone reduced fever to normothermic levels in the group treated acutely with EGb 761 (p < 0.01 vs saline, p > 0.05 vs sham) but not after chronic EGb 761 (p < 0.01 vs sham), indicating possible pharmacokinetic interaction. In conclusion, within the context of unprevented, ischemia‐induced fever, the present results demonstrate that EGb 761 has no significant effect on brain infarct size. Copyright © 2006 John Wiley & Sons, Ltd.
Enhancing Vocabulary Selection for Preschoolers Who Require Augmentative and Alternative Communication (AAC)
Authors: Fallon Karen A. , Light Janice C. , Paige Tara Kramer
Published: April 2006

Augmentative and alternative communication (AAC) systems (e.g., communication books of line drawings, computer-based voice output systems) offer children with severe communication disabilities increased opportunities for participation in home, school, and community activities. However, without the appropriate vocabulary, AAC systems will not be effective. This project addressed the challenge of vocabulary selection for children who require AAC through two studies: (1) analysis of the vocabulary of typically developing preschoolers and (2) subsequent development and field testing of a vocabulary selection questionnaire. Language samples from five typically developing preschool children were analyzed to determine the words used and the content of the preschoolers’ language. Results indicated that a large portion of the words used by the participants was accounted for by a relatively limited number of words. Using these data and data from other studies in the field, a vocabulary selection questionnaire for professionals and parents was developed and field-tested. A total of 45 speech-language pathologists, teachers, and parents indicated a high level of satisfaction, with 93% of informants reporting that they would use the tool again and 98% of informants indicating that they would recommend it to other parents and professionals. Results from both studies are presented and discussed with reference to clinical implications and future research directions.
The Sixth View
Authors: Khan Linda M.
Published: April 2006

The forum participants have described their procedures for evaluating Bobby's speech. Each has a specific flavor to it. Bleile strives for "balancing thoroughness against efficiency" and is concerned about keeping both Bobby and his parents comfortable during the evaluation. Hodson et al. seem to center their evaluation around "readiness for literacy," which requires a strong phonological system and metaphonological awareness. Hoffman & Norris use no standardized tests, preferring to derive all data from a "naturalistic" interaction with Bobby. Miccio is sensitive to cultural differences and the influence of the "unnatural" clinical setting on such a young child. Her evaluation is also the most thorough in its focus on the phonological system at multiple levels. Tyler & Tolbert emphasize the "multidimensional" nature of the assessment: standardized and nonstandardized evaluation, adjusting to Bobby's personality and preferences.

What is my view of the elephant? Because of time constraints and eligibility requirements, I focus on obtaining the information required for determining eligibility: "Quick and Dirty." For Bobby, this means a standardized articulation/phonology score, oral peripheral screening, and hearing screening. The additional information can be obtained later. Determining initial treatment goals can be accomplished at my desk after school.

This is the sixth view: from the trenches
. In attempting to "balance thoroughness against efficiency," efficiency wins. If the referral is for articulation/phonology, then that will be the focus of the evaluation. Caseload size and time constraints determine that establishing eligibility is the highest priority, followed by the development of initial treatment goals. If I haven't completed Bobby's language testing during the evaluation session, at the very least I will have gathered preliminary evidence to suggest the presence or absence of a language impairment. Further evaluation of the communication system may be completed during the first few therapy sessions. As additional information is gathered, IEP goals are revised or augmented as needed. Bobby is on his way to intelligibility.
Language Development and Delay in Internationally Adoped Infants and Toddlers
Authors: Glennen Sharon
Published: April 2006

When children change cultures through adoption, they experience a transition from a birth first language to a new adoptive first language. Because adoptive families rarely speak the birth language, use of that language arrests at the time of adoption and undergoes attrition while the child learns the new adopted language. During this process, internationally adopted children have limited abilities in both languages. This makes it difficult to determine which children require speech and language services, and which will learn the new language spontaneously over time. This article reviews information on arrested language development in bilingual children and applies it to the internationally adopted child. The influence of cross-linguistic patterns of transfer and interference in infants and toddlers is explored, along with the medical and developmental risks associated with children adopted from orphanages. The primary goal of this article is to help professionals understand post-adoption language learning issues affecting internationally adopted children, as well as the impact of preadoption history on those developmental processes.
A New CAPD Battery—Multiple Auditory Processing Assessment
Authors: Domitz Deborah M. , Schow Ronald L.
Published: April 2006

Based on recommendations by Musiek & Chermak (1994,
American Journal of Audiology, 3
, 23–27) and ASHA (1996,
American Journal of Audiology, 5
(2), 41–54), a battery of four commonly used tests was selected and recorded for use in assessing school children. These tests were labeled the Multiple Auditory Processing Assessment (MAPA) and then administered to an initial sample of 81 third grade children, along with the SCAN screening test for auditory processing disorders. Afterward, several exploratory factor analyses were performed on the findings, and comparisons were made between the results for the MAPA and SCAN. Four separate factors emerged from the four MAPA tests, which were linked closely to the components of central auditory processing disorders (CAPDs) defined by ASHA (1996,
American Journal of Audiology, 5
(2), 41–54). These factors were labeled monaural separation/closure (MSC), auditory pattern/temporal ordering, binaural integration, and binaural separation (BS). SCAN appears to measure two of these factors, MSC and BS. Use of MAPA is encouraging. Our findings suggest it may provide an appropriate multiple-test, CAPD battery for third grade children, and it meets at least some of the objectives described in the consensus document proposed by ASHA (1996,
American Journal of Audiology, 5
(2), 41–54).
The Prediction of Hearing Loss in Persons With Cerebral Palsy Using Contralateral Acoustic Reflex Threshold for Broad-Band Noise
Authors: Emmer Michele B. , Silman Shlomo
Published: April 2006

The utility of R. Keith’s (1977) method of screening for hearing sensitivity using the contralateral acoustic-reflex threshold (ART) for broad-band noise (BBN) was tested in persons with cerebral palsy (CP). Three groups of participants were included in this prospective study. The first group comprised 20 normal-hearing individuals without CP whose results were used as normative data. The second group comprised 16 participants with normal hearing and CP. The third group comprised 22 participants with sensorineural hearing loss and CP. The results of this study indicate that Keith’s screening method employing ART for BBN can be used successfully in a population with multiple handicaps where a quick, inexpensive, readily available, and accurate method is needed.
Time Estimation by Adults Who Stutter
Authors: Ezrati-Vinacour Ruth , Levin Iris
Published: April 2006

In view of the fact that stuttering involves time pressure in communicative contexts, the aim of this investigation was to study the effect of stuttering on time estimation. Two matching groups of 47 adults each, one consisting of stutterers and the other of fluent speakers, estimated the duration of four verbal tasks—two that involved speaking and two that did not. Two methods of time estimation were used: production and reproduction. In production, participants were required to perform a task, terminating it when they felt that the specified interval had elapsed. In reproduction, participants were asked to estimate the duration of a task immediately after being stopped by the experimenter. The results reveal that the differences in time estimation between adults who stutter and fluent speakers were task dependent, with the stutterers estimating time less accurately on oral verbal tasks. The conversation task in particular highlighted the inaccuracy of their time estimation. Furthermore, severe stutterers estimated time less accurately than mild stutterers. The greatest inaccuracy was displayed by severe stutterers when estimating the time of an oral task by the production method. The results are discussed in terms of cognitive models based on attention to time, method measurement, and mental workload. Clinical implications are also suggested.
Training Volunteers as Conversation Partners Using "Supported Conversation for Adults With Aphasia" (SCA)
Authors: Kagan Aura , Black Sandra E. , Duchan Judith Felson , Simmons-Mackie Nina , Square Paula
Published: April 2006

This article reports the development and evaluation of a new intervention termed "Supported Conversation for Adults with Aphasia" (SCA). The approach is based on the idea that the inherent competence of people with aphasia can be revealed through the skill of a conversation partner. The intervention approach was developed at a community-based aphasia center where volunteers interact with individuals with chronic aphasia and their families. The experimental study was designed to test whether training improves the conversational skills of volunteers, and, if so, whether the improvements affect the communication of their conversation partners with aphasia. Twenty volunteers received SCA training, and 20 control volunteers were merely exposed to people with aphasia. Comparisons between the groups’ scores on a Measure of Supported Conversation for Adults with Aphasia provide support for the efficacy of SCA. Trained volunteers scored significantly higher than untrained volunteers on ratings of acknowledging competence [F(1, 36)=19.1,p< .001] and revealing competence [F(1, 36)=159.0,p< .001] of their partners with aphasia. The training also produced a positive change in ratings of social [F(1, 36)=5.7,p< .023] and message exchange skills [F(1, 36)=17.6,p< .001] of individuals with aphasia, even though these individuals did not participate in the training. Implications for the treatment of aphasia and an argument for a social model of intervention are discussed.
Perceptual Weighting of Relative Amplitude and Formant Transition Cues in Aided CV Syllables
Authors: Hedrick Mark , Younger Mary Sue
Published: April 2006

The current study explored the changes in weighting of relative amplitude and formant transition cues that may be caused by a K-amp circuit. Twelve listeners with normal hearing and 3 listeners with sensorineural hearing loss labeled the stop consonant place of articulation of synthetic consonant-vowel stimuli. Within the stimuli, two acoustic cues were varied: the frequency of the onset of the second and third formant (F2/F3) transitions and the relative amplitude between the consonant burst and the following vowel in the fourth and fifth formant (F4/ F5) frequency region. The variation in the two cues ranged from values appropriate for a voiceless labial stop consonant to a voiceless alveolar stop consonant. The listeners labeled both the unaided stimuli and the stimuli recorded through a hearing aid with a K-amp circuit. An analysis of variance (ANOVA) model was used to calculate the perceptual weight given each cue. Data from listeners with normal hearing show a change in relative weighting of cues between aided and unaided stimuli. Pilot data from the listeners with hearing loss show a more varied pattern, with more weight placed on relative amplitude. These results suggest that calculation of perceptual weights using an ANOVA model may be worthwhile in future studies examining the relationship between acoustic information presented by a hearing aid and the subsequent perception by the listener with hearing loss.
Consonant Cluster Development in Two-Year-Olds
Authors: McLeod Sharynne , Doorn Jan van , Reed Vicki A.
Published: April 2006

A holistic view of phonological development can be attained only through exploration of the relationship between universal developmental sequences, to establish a general pattern of development and individual learning and to provide information regarding variability. This study examined consonant cluster production, looking specifically at the relationship between general trends and individual differences as children acquire these sounds. The spontaneous speech of 16 normally developing Anglo-Australian 2-year-olds was elicited monthly for 6 months, and the corpus of 96 samples was examined using independent and relational phonological analyses. Data demonstrated that 2-year-olds were able to produce a range of consonant clusters in word-initial and word-final position, but few of the younger participants could produce consonant clusters correctly. Only half of the participants showed an increase in the percent of consonant clusters produced correctly over the 6-month period; however, their developing phonological maturity was revealed in the increase in the range and diversity of their repertoire of consonant clusters and by their closer approximations to the adult target. Specific findings of the study were compared to 10 trends for children's acquisition of consonant clusters emerging from the literature over the last 70 years.
Children's Recognition of Cartoon Voices
Authors: Spence Melanie J. , Rollins Pamela R. , Jerger Susan
Published: April 2006

We examined developmental changes in talker recognition skills by assessing 3-, 4-, and 5-year-old children's recognition of 20 cartoon characters' voices. For each participant, the character set was subdivided into more and less familiar talkers based on the participant's ability to name each character. Four- and 5-year-old children recognized more of the voices (81% and 86%, respectively) than did 3-year-olds (61%), although performance of all age groups was well above chance. All groups of children were more accurate at recognizing more familiar than less familiar characters. These results suggest that indexical information about a talker becomes an integral part of the perceptual record in memory and can be used by children at a very young age. These results are important because children's ability to learn vocal sources may be an important aid to the development of spoken word recognition.
Phoneme Recognition and Confusions With Multichannel Cochlear Implants
Authors: Välimaa Taina T. , Määttä Taisto K. , Löppönen Heikki J. , Sorri Martti J.
Published: April 2006

The aim of this study was to investigate how postlingually severely or profoundly hearing-impaired adults relearn to recognize vowels after receiving multichannel cochlear implants. Vowel recognition of 19 Finnish-speaking subjects was studied for a minimum of 6 months and a maximum of 24 months using an open-set nonsense-syllable test in a prospective repeated-measure design. The responses were coded for phoneme errors, and 95% confidence intervals for recognition and confusions were calculated. The average vowel recognition was 68% (95% confidence interval = 66–70%) 6 months after switch-on and 80% (95% confidence interval = 78–82%) 24 months after switch-on. The vowels [æ], [u], [i], [o], and [a] were the easiest to recognize, and the vowels [y], [e], and [ø] were the most difficult. In conclusion, adaptation to electrical hearing using a multichannel cochlear implant was achieved well; but for at least 2 years, given two vowels with either F1 or F2 at roughly the same frequencies, confusions were drawn more towards the closest vowel with the next highest F1 or F2.
Changes in the Human Vocal Tract Due to Aging and the Acoustic Correlates of Speech Production
Authors: Xue Steve An , Hao Grace Jianping
Published: April 2006

This investigation used a derivation of acoustic reflection (AR) technology to make cross-sectional measurements of changes due to aging in the oral and pharyngeal lumina of male and female speakers. The purpose of the study was to establish preliminary normative data for such changes and to obtain acoustic measurements of changes due to aging in the formant frequencies of selected spoken vowels and their long-term average spectra (LTAS) analysis. Thirty- eight young men and women and 38 elderly men and women were involved in the study. The oral and pharyngeal lumina of the participants were measured with AR technology, and their formant frequencies were analyzed using the Kay Elemetrics Computerized Speech Lab. The findings have delineated specific and similar patterns of aging changes in human vocal tract configurations in speakers of both genders. Namely, the oral cavity length and volume of elderly speakers increased significantly compared to their young cohorts. The total vocal tract volume of elderly speakers also showed a significant increment, whereas the total vocal tract length of elderly speakers did not differ significantly from their young cohorts. Elderly speakers of both genders also showed similar patterns of acoustic changes of speech production, that is, consistent lowering of formant frequencies (especially F1) across selected vowel productions. Although new research models are still needed to succinctly account for the speech acoustic changes of the elderly, especially for their specific patterns of human vocal tract dimensional changes, this study has innovatively applied the noninvasive and cost-effective AR technology to monitor age-related human oral and pharyngeal lumina changes that have direct consequences for speech production.
Adjective Definitions and the Influence of Word Frequency
Authors: Marinellie Sally A. , Johnson Cynthia J.
Published: April 2006

The present investigation is a study of the development of adjective definitions given by participants in Grades 6 and 10 and by young adults, as well as the influence of word frequency on those definitions. A total of 150 participants (50 per age group) wrote definitions for 6 high-frequency and 6 low-frequency adjectives. Adjective definitions were analyzed for use of semantic content and also grammatical form. Findings indicated that content of adjective definitions generally followed a developmental course from concrete and functional to more abstract. Response patterns of certain categories, such as superordinate, have implications for organization of the mental lexicon and suggest that adjective definitions may be less predictable than definitions of other grammatical categories, such as noun. Although conventional syntactic form was highly used in definitions (i.e., adjectival form for a definition of an adjective), verb form was also highly used. Conventional form may be less useful to characterize adjective definitions than other grammatical classes. Findings suggest that word frequency has a robust influence on adjective definitions and that development progresses differently for high- and low-frequency words.
Responses to Targets in the Visual Periphery in Deaf and Normal-Hearing Adults
Authors: Rothpletz Ann M. , Ashmead Daniel H. , Tharpe Anne Marie
Published: April 2006

The purpose of this study was to compare the response times of deaf and normal-hearing individuals to the onset of target events in the visual periphery in distracting and nondistracting conditions. Visual reaction times to peripheral targets placed at 3 eccentricities to the left and right of a center fixation point were measured in prelingually deafened adults and normal-hearing adults. Deaf participants responded more slowly than normal-hearing participants to targets in the near periphery in the nondistracting condition and to targets in the near and distant periphery when distracting stimuli were present. One interpretation of these findings is that deaf individuals may be more deliberate than normal-hearing individuals in responding to near peripheral events and to peripheral events that occur in the presence of distracting stimuli.
Rate and Loudness Manipulations in Dysarthria
Authors: Tjaden Kris , Wilding Gregory E.
Published: April 2006

Both rate reduction and increased loudness reportedly are associated with an increase in the size of the articulatory-acoustic working space and improved acoustic distinctiveness for speakers with dysarthria. Improved intelligibility also has been reported. Few studies have directly compared rate and loudness effects for speakers with dysarthria, however, although rate reduction and increasing vocal loudness are common treatment techniques. In the current study, 15 speakers with dysarthria secondary to multiple sclerosis, 12 speakers with dysarthria secondary to Parkinson’s disease (PD), and 15 healthy controls read a passage in
habitual, loud
, and
slow
conditions. Rate and loudness variations were elicited using magnitude production. Acoustic measures included articulatory rate, sound pressure level, vowel space area, first moment difference measures, and F2 trajectory characteristics for diphthongs. Ten listeners scaled intelligibility for reading passages produced by the speakers with dysarthria. Relationships between intelligibility estimates and acoustic measures were determined by regression analysis. All speaker groups reduced articulatory rate for the slow condition and increased vocal intensity for the loud condition, relative to the habitual condition. Vowel acoustic distinctiveness, as indexed by vowel space area, was maximized in the slow condition, but stop consonant acoustic distinctiveness, as indexed by first moment difference measures, was maximized in the loud condition. F2 slope measures for diphthongs were not consistently affected by rate or loudness. Scaled intelligibility for speakers with PD also improved in the loud condition relative to both the habitual and slow conditions. Intelligibility estimates for speakers with dysarthria, however, were not strongly related to acoustic measures of supraglottal behavior. Findings are compared with previous studies, and hypotheses for future treatment studies are discussed.
Do Data From Children With Specific Language Impairment Support the Agreement/Tense Omission Model?
Authors: Pine Julian M. , Joseph Kate L. , Conti-Ramsden Gina
Published: April 2006

One of the most influential recent accounts of pronoun case-marking errors in children’s speech is C. T. Schütze and K. Wexler’s (1996) agreement/tense omission model (ATOM). This model predicts that non-nominative subjects with agreeing verbs will be so rare that they can be reasonably disregarded as noise in the data. The present study tested this prediction on data from 4 children with specific language impairment (SLI) by comparing the frequency with which each child produced non-nominative subjects with agreeing verbs and the frequency with which they would be expected to produce such errors by chance given the number of nominative and non-nominative subjects and the number of agreeing and nonagreeing verb forms in the data. The results show (a) that although 3 of the 4 children used non-nominative subjects in their speech, only 2 of them (Nathan and Dan) produced non-nominative subjects with agreeing verbs significantly less often than one would expect by chance; (b) that to the extent that there was an asymmetry in Nathan’s and Dan’s use of nominative and nonnominative subjects with agreeing verbs, this asymmetry could be explained in terms of developmental changes in their ability to mark case and agreement correctly and the use of potentially unanalyzed contractions; and (c) that Nathan and Dan produced non-nominative subjects with noncontracted agreeing forms about as often as one would expect by chance. These findings are discussed in terms of their theoretical implications for the ATOM and their methodological implications for future work on patterns of pronoun case marking error in the speech of typically developing children and children with SLI.
Comparison of Measures of Variability of Speech Movement Trajectories Using Synthetic Records
Authors: Lucero Jorge C.
Published: April 2006

In speech research, it is often desirable to assess quantitatively the variability of a set of speech movement trajectories. This problem is studied here using synthetic trajectories, which consist of a common pattern and terms representing amplitude and phase variability. The results show that a technique for temporal alignment of the records based on functional data analysis allows us to extract the pattern and variability terms as separate functions, with good approximation. Indices of amplitude and phase variability are defined, which provide a more accurate assessment of variability than previous approaches.
Benefit of Wearing a Hearing Aid on the Unimplanted Ear in Adult Users of a Cochlear Implant
Authors: Dunn Camille C. , Tyler Richard S. , Witt Shelley A.
Published: April 2006

The purpose of this investigation was to document performance of participants wearing a cochlear implant and hearing aid in opposite ears on speech-perception and localization tests. Twelve individuals who wore a cochlear implant and a hearing aid on contralateral ears were tested on their abilities to understand words in quiet and sentences in noise, and to localize everyday sounds. All speech stimuli were presented from the front, with the noise stimuli presented from the front, the right, or the left at a 90° angle. Binaural summation in quiet and in noise, binaural squelch effects, and localization were studied to determine bilateral advantages. The magnitude of the monaural head shadow effect (the difference in unilateral performance when noise was facing the unilateral device vs. when the noise was opposite the unilateral device) also was studied. The test setup for localization was composed of an 8-speaker array spanning an arc of approximately 108° in front of each participant. Group results yielded a statistically significant combined benefit of wearing a hearing aid in conjunction with a cochlear implant on opposite ears in noise conditions. Those participants who received a binaural advantage in 1 condition did not necessarily show a binaural advantage in another. Only 2 participants out of 12 were able to localize when wearing 2 devices. Further efforts are required to improve the integration of information from combined use of cochlear implant and hearing aid devices for enhancement of speech perception in noise and localization.
Comparison of Clinician Judgments and Measurements of Swallow Response Time
Authors: Karnell Michael P. , Rogus Nicole M.
Published: April 2006

Practicing clinicians frequently offer judgments about aspects of swallowing physiology rather than performing actual measurements. Little is known about the accuracy of those judgments. The purpose of this preliminary study was to explore agreement of clinicians' judgments of pharyngeal swallow response time (PSRT) with temporal measurements of PSRT. In preparation for a larger study, PSRT was measured from the first 3 ml liquid bolus swallow that appeared in each of 20 videofluorographic swallowing evaluations. The same 20 swallows were then shown to 3 clinicians who were instructed to subjectively rate PSRT. The reliability of the PSRT measurements was strong (
r
> .95). Intrajudge and interjudge agreement was better than chance in all but 1 interjudge comparison. Percentage agreement between clinicians' judgments and the measurements, when the measurements were categorized as either not delayed or delayed, ranged from 60% to 95%. Chi-square and Phi statistics comparing the outcomes of clinicians' ratings with the measurement outcomes were significant, supporting the agreement of the judgments with the measurements. Although the results of tests of agreement were found to be acceptable, clinician experience and training remain important issues whenever clinical judgments are involved. Larger studies are needed to establish the accuracy and importance of clinicians' judgments of PSRT and observations of swallowing physiology.
Signatures of non locality for short-ranged wetting at curved substrates
Authors: Parry A. O. , Rascón C. , Morgan L.
Published: April 2006

The binding potential for wetting near planes, spheres, and cylinders in systems with short-ranged forces is shown to have a universal geometrical structure. This arises from the nonlocal nature of the interfacial interactions and is exactly described by a recently proposed binding potential functional, which provides a systematic framework for studying wetting at arbitrarily shaped substrates. The corrections to the equilibrium wetting layer thickness induced by nonlocality are comparable to those arising from a Tolman length and lead to diverging terms in the total mass adsorption.