bluuebunny/crossref_metadata_2025 huggingface dataset:
The Performance of Typically Developing 2½-Year-Olds on Dynamic Display AAC Technologies With Different System Layouts and Language Organizations
Authors: Drager Kathryn D. R. , Light Janice C. , Speltz JoHannah Curran , Fallon Karen A. , Jeffries Lauren Z.
Published: April 2006

The current generation of augmentative and alternative communication (AAC) technologies is largely based on conceptual models of adults who are not disabled (J. Light & P. Lindsay, 1991). As a result, there is a large "cost of learning" placed on young children. This paper presents the results of a study designed to investigate the learning demands of dynamic display systems that differed in system layout and language organization for children approximately 2 1/2 years old (2 years 5 months to 2 years 11 months). Thirty typically developing children were asked to locate 12 vocabulary items within a play context of a birthday party. Ten children were randomly assigned to each of 3 system approaches: vocabulary in a grid format organized taxonomically, vocabulary in a grid format organized schematically, and vocabulary in an integrated scene organized schematically. The children participated in 4 learning and testing sessions and 1 generalization session. Results indicated that the children performed poorly in all conditions but were able to locate more vocabulary items in the schematic scene condition than the taxonomic grid or schematic grid conditions. There was evidence that the children failed to generalize their knowledge of the vocabulary to facilitate learning of novel vocabulary items. The current design of AAC dynamic display systems appears to be inappropriate for very young children. Rather than relying solely on technology for these young children, early intervention should target multiple modes of communication. AAC technologies should be redesigned to reduce learning demands. Results are discussed with implications for practice and suggestions for future research.
Specific Language Impairment in Families
Authors: Flax Judy F. , Realpe-Bonilla Teresa , Hirsch Linda S. , Brzustowicz Linda M. , Bartlett Christopher W. , Tallal Paula
Published: April 2006

Two family aggregation studies report the occurrence and co-occurrence of oral language impairments (LIs) and reading impairments (RIs). Study 1 examined the occurrence (rate) of LI and RI in children with specific language impairment (SLI probands), a matched control group, and all nuclear family members. Study 2 included a larger sample of SLI probands, as well as their nuclear and extended family members. Probands and their family members who met specific criteria were classified as language and/or reading impaired based on current testing. In Study 1, the rates of LI and RI for nuclear family members (excluding probands) were significantly higher than those for control family members. In the SLI families, affected family members were more likely to have both LI and RI than either impairment alone. In Study 2, 68% of the SLI probands also met the diagnostic classification for RI. The language and RI rates for the other family members, excluding probands, were 25% and 23% respectively, with a high degree of co-occurrence of LI and RI (46%) in affected individuals. Significant sex ratio differences were found across generations in the families of SLI probands. There were more male than female offspring in these families, and more males than females were found to have both LIs and RIs. Results demonstrate that when LIs occur within families of SLI probands, these impairments generally co-occur with RIs. Our data are also consistent with prior findings that males show impairments more often than females.
Relevance and Speed of Message Delivery Trade-Offs in Augmentative and Alternative Communication
Authors: Bedrosian Jan L. , Hoag Linda A. , McCoy Kathleen F.
Published: April 2006

This report is the first in a series of investigations designed to test a theory identifying the effects of conversational trade-offs between selected maxims on public attitudes toward augmentative and alternative communication (AAC) system users and their communication. In the current study, the trade-offs between the relevance of a prestored message and its speed of delivery were examined. Participating were 96 sales clerks. Twelve scripted videotaped conversational conditions, involving an AAC customer and a clerk at a checkout counter, were used to manipulate message relevance, speed of message delivery, and participant/AAC user gender. Following each assigned viewing, participants completed a questionnaire designed to assess their attitudes toward the AAC user and his or her communication. Significantly higher mean ratings were found for the conditions involving the slowly delivered relevant messages (both preceded by a conversational floorholder and without a floorholder) when compared to the quickly delivered partly relevant message condition. In addition, the condition involving the slowly delivered relevant message with a floorholder yielded significantly higher mean ratings than that without the floorholder. There was no effect for participant/user gender. Modifications of the theory and technological implications are discussed.
Perceptual Evaluation of Tracheoesophageal Speech by Naive and Experienced Judges Through the Use of Semantic Differential Scales
Authors: As Corina J. van , Beinum Florien J. Koopmans-van , Pols Louis C. W. , Hilgers Frans J. M.
Published: April 2006

The present study was conducted to investigate voice quality in tracheoesophageal speech by means of perceptual evaluations and to develop a clinically useful subset of perceptual scales sufficient for these perceptual evaluations. The perceptual ratings were obtained from both naive and trained raters (speechlanguage pathologists [SLPs]) after listening to a read-aloud text. The perceptual evaluations were performed by means of 19 semantic bipolar 7-point scales for the naive raters and 20 semantic bipolar 7-point scales for the trained raters. The trained raters were also asked to judge the overall voice quality as good, reasonable, or poor. Both naive listeners and trained SLPs were able to perform reliable perceptual judgments. Naive raters judged the tracheoesophageal voice as more deviant than the trained raters did. Naive raters made judgments based on 2 underlying perceptual dimensions (voice quality and pitch), whereas the trained raters made judgments based on 4 underlying perceptual dimensions (voice quality, tonicity, pitch, and tempo). These perceptual dimensions were further subdivided into a subset of 4 perceptual scales for the naive raters and a subset of 8 perceptual scales for the trained raters. This appeared to provide a sufficient coverage of the underlying perceptual dimensions used by the listeners.
Association of Orofacial Muscle Activity and Movement During Changes in Speech Rate and Intensity
Authors: McClean Michael D. , Tasko Stephen M.
Published: April 2006

Understanding how orofacial muscle activity and movement covary across changes in speech rate and intensity has implications for the neural control of speech production and the use of clinical procedures that manipulate speech prosody. The present study involved a correlation analysis relating average lower-lip and jaw-muscle activity to lip and jaw movement distance, speed, and duration. Recordings were obtained on orofacial movement, muscle activity, and the acoustic signal in 3 normal speakers as they repeated a simple test utterance with targeted speech rates varying from 60% to 160% of their habitual rate and at targeted vocal intensities of –6 dB and +6 dB relative to their habitual intensity. Surface electromyographic (EMG) recordings were obtained with electrodes positioned to sample primarily the mentalis, depressor labii inferior, anterior belly of the digastric, and masseter muscles. Two-dimensional displacements of the lower lip and jaw in the midsagittal plane were recorded with an electromagnetic system. All participants produced linear changes in percent utterance duration relative to the auditory targets for speech rate variation. Intensity variations ranged from –10 dB to +8 dB. Average EMG levels for all 4 muscles were well correlated with specific parameters of movement. Across the intensity conditions, EMG level was positively correlated with movement speed and distance in all participants. Across the rate conditions, EMG level was negatively correlated with movement duration in all participants, while greater interparticipant variability was noted for correlations relating EMG to speed and distance. For intensity control, it is suggested that converging neural input to orofacial motoneurons varies monotonically with movement distance and speed. In contrast, rate control appears to be more strongly related to the temporal characteristics of neural input than activation level.
Orofacial Movements Associated With Fluent Speech in Persons Who Stutter
Authors: McClean Michael D. , Tasko Stephen M. , Runyan Charles M.
Published: April 2006

This study was intended to replicate and extend previous findings that (a) during fluent speech persons who stutter (PS) and those who do not (NS) differ in their vocal tract closing movements (L. Max, A. J. Caruso, & V. L. Gracco, 2003) and (b) ratios relating lip and tongue speed to jaw speed increase with stuttering severity (M. D. McClean & C. R. Runyan, 2000). An electromagnetic system was used to record movements of the upper lip, lower lip, tongue, and jaw of 43 NS and 37 PS during productions of a nonsense phrase and a sentence. Measurement and analysis of movement speeds, durations, and ratios of lip and tongue speed to jaw speed were performed on fluent productions of a nonsense phrase and sentence. Statistical comparisons were made between PS with low and high stuttering severity levels (LPS and HPS) and NS. Significant variations across groups in movement speed and duration were observed, but the pattern of these effects was complex and did not replicate the results of the two earlier studies. In the nonsense phrase, significant reductions in lower lip closing duration, jaw closing duration, and jaw closing speed were seen in PS. In the sentence task, HPS showed elevated tongue opening and closing durations. For tongue opening in the sentence, LPS showed elevated speeds and HPS showed reduced speeds. The elevated speeds for LPS are interpreted as a contributing factor to speech disfluency, whereas the reduced speeds and increased durations in HPS are attributed to adaptive behavior intended to facilitate fluent speech. Significant group effects were not seen for the speed ratio measures. Results are discussed in relation to multivariate analyses intended to identify subgroups of PS.
Semantic Features in Fast-Mapping
Authors: Alt Mary , Plante Elena , Creusere Marlena
Published: April 2006

This study examined the receptive language skills of young children (4–6 years old) with specific language impairment (SLI). Specifically, the authors looked at their ability to fast-map semantic features of objects and actions and compared it to the performance of age-matched peers with normally developing language (NL). Children completed a computer task during which they were exposed to novel objects and actions with novel names. The children then were asked questions about the semantic features of these novel objects and actions. Overall, the questions about actions were more difficult for children than objects. The children with SLI were able to recognize fewer semantic features than were their peers with NL. They also performed poorly relative to their peers on a lexical label recognition task. These results lend support to the idea that children with SLI have broader difficulties with receptive vocabulary than simply a reduced ability to acquire labels.
Air Pressure Responses to Sudden Vocal Tract Pressure Bleeds During Production of Stop Consonants
Authors: Zajac David J. , Weissler Mark C.
Published: April 2006

Two studies were conducted to evaluate short-latency vocal tract air pressure responses to sudden pressure bleeds during production of voiceless bilabial stop consonants. It was hypothesized that the occurrence of respiratory reflexes would be indicated by distinct patterns of responses as a function of bleed magnitude. In Study 1, 19 adults produced syllable trains of /pʌ/ using a mouthpiece coupled to a computer-controlled perturbator. The device randomly created bleed apertures that ranged from 0 to 40 mm
2
during production of the 2nd or 4th syllable of an utterance. Although peak oral air pressure dropped in a linear manner across bleed apertures, it averaged 2 to 3 cm H
2
O at the largest bleed. While slope of oral pressure also decreased in a linear trend, duration of the oral pressure pulse remained relatively constant. The patterns suggest that respiratory reflexes, if present, have little effect on oral air pressure levels. In Study 2, both oral and subglottal air pressure responses were monitored in 2 adults while bleed apertures of 20 and 40 mm
2
were randomly created. For 1 participant, peak oral air pressure dropped across bleed apertures, as in Study 1. Subglottal air pressure and slope, however, remained relatively stable. These patterns provide some support for the occurrence of respiratory reflexes to regulate subglottal air pressure. Overall, the studies indicate that the inherent physiologic processes of the respiratory system, which may involve reflexes, and passive aeromechanical resistance of the upper airway are capable of developing oral air pressure in the face of substantial pressure bleeds. Implications for understanding speech production and the characteristics of individuals with velopharyngeal dysfunction are discussed.

KEY WORDS: stop consonants, oral air pressure, subglottal air pressure, respiratory reflexes, velopharyngeal dysfunction
Verbal Working Memory in Bilingual Children
Authors: Gutiérrez-Clellen Vera F. , Calderón Janet , Weismer Susan Ellis
Published: April 2006

The present study compared the performance of 44 Latino children on the Competing Language Processing Task (CLPT; C. Gaulin & T. Campbell, 1994) and the Dual Processing Comprehension Task (DPCT; S. Ellis Weismer, 1996). First, it was of interest to know if there were significant differences between children with and without bilingual proficiency on processing tasks that were assumed to require limited vocabulary knowledge. The second goal of this research was to determine whether there were cross-linguistic differences in verbal working memory by examining performance within bilinguals and between children with limited proficiency in a second language. The performance of the participating children was also examined in the context of research with other English-speaking groups. Finally, given that the CLPT and the DPCT may differ in their processing demands (from a relative focus on storage to one of attention inhibition or resistance to interference), it was important to know the extent to which these tasks were related or involved similar cognitive-linguistic operations. Results revealed shared processing skills as well as differences related to individual attainments in bilingual acquisition.
The Search for Common Ground
Authors: Windsor Jennifer , Kohnert Kathryn
Published: April 2006

This study examines lexical performance by 3 groups of linguistically diverse school-age learners: English-only speakers with primary language impairment (LI), typical English-only speakers (EO), and typical bilingual Spanish-English speakers (BI). The accuracy and response time (RT) of 100 8- to 13-year-old children in word recognition and picture-naming tasks were analyzed. Within each task, stimulus difficulty was manipulated to include very easy stimuli (words that were high frequency/had an early age of acquisition in English) and more difficult stimuli (words of low frequency/late age of acquisition [AOA]). There was no difference among groups in real-word recognition accuracy or RT; all 3 groups showed lower accuracy with low-frequency words. In picture naming, all 3 groups showed a longer RT for words with a late AOA, although AOA had a disproportionate negative impact on BI performance. The EO group was faster and more accurate than both LI and BI groups in conditions with later acquired stimuli. Results are discussed in terms of quantitative differences separating EO children from the other 2 groups and qualitative similarities linking monolingual children with and without LI.
Auditory Processing Efficiency and Temporal Resolution in Children and Adults
Authors: Hill Penelope R. , Hartley Douglas E. H. , Glasberg Brian R. , Moore Brian C. J. , Moore David R.
Published: April 2006

Children have higher auditory backward masking (BM) thresholds than adults. One explanation for this is poor temporal resolution, resulting in difficulty separating brief or rapidly presented sounds. This implies that the auditory temporal window is broader in children than in adults. Alternatively, elevated BM thresholds in children may indicate poor processing efficiency. In this case, children would need a higher signal-to-masker ratio than adults to detect the presence of a signal. This would result in poor performance on a number of psychoacoustic tasks but would be particularly marked in BM due to the compressive nonlinearity of the basilar membrane. The objective of the present study was to examine the competing hypotheses of "temporal resolution" and "efficiency" by measuring BM as a function of signal-to-masker interval in children and adults. The children had significantly higher thresholds than the adults at each of the intervals. Subsequent modeling and analyses showed that the data for both children and adults were best fitted using the same, fixed temporal window. Therefore, the differences in BM threshold between adults and children were not due to differences in temporal resolution but to reduced detection efficiency in the children.
An Across-Frequency Processing Deficit in Listeners With Hearing Impairment Is Supported by Acoustic Correlation
Authors: Healy Eric W. , Kannabiran Anand , Bacon Sid P.
Published: April 2006

It has been recently suggested that listeners having a sensorineural hearing impairment (HI) may possess a deficit in their ability to integrate speech information across different frequencies. When presented with a task that required across-frequency integration of speech patterns, listeners with HI performed more poorly than their normal-hearing (NH) counterparts (E. W. Healy & S. P. Bacon, 2002; C. W. Turner, S.-L. Chi, & S. Flock, 1999). E. W. Healy and S. P. Bacon (2002) also showed that performance of the listeners with HI fell more steeply when increasing amounts of temporal asynchrony were introduced to the pair of widely separated patterns. In the current study, the correlations between the fluctuating envelopes of the acoustic stimuli were calculated, both when the patterns were aligned and at various between-band asynchronies. It was found that the rate at which acoustic correlation fell as a function of asynchrony closely matched the rate at which intelligibility fell for the NH listeners. However, the intelligibility scores produced by the listeners with HI fell more steeply than the acoustic analysis would suggest. Thus, these data provide additional support for the hypothesis that individuals having sensorineural HI may have a deficit in their ability to integrate speech information present at different frequencies.
Carrier transfer induced photoluminescence change in metal-semiconductor core-shell nanostructures
Authors: Lin H. Y. , Chen Y. F. , Wu J. G. , Wang D. I. , Chen C. C.
Published: April 2006

Metal-semiconductor core-shell nanostructures have been synthesized to explore the influence of metal nanostructures on the photoluminescence of semiconductors. Up to 40 times enhancement in the emission intensity was observed in the Au–CdS core-shell nanostructures. The mechanism where the excited electrons on Au surface by surface plasmon wave transfer to the conduction band of the CdS shell and recombine with holes in the valence band was proposed to interpret the enhancement. Our model can also be used to explain the quenched emission in FePt–CdS core-shell nanostructures and Au–CdSe nanodumbbells.
Survey of Long-Term-Care Facilities in Iowa for Policies and Practices Regarding Residents With Methicillin-Resistant Staphylococcus aureus or Vancomycin-Resistant Enterococci
Authors: Kreman Trisha , Hu Jianfang , Pottinger Jean , Herwaldt Loreen A.
Published: April 2006

Objectives:

To identify infection control policies and practices used by long-term-care facilities (LTCFs) in Iowa for residents with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE), and to estimate the prevalence of residents known to have these organisms.

Design:

Survey.

Setting:

LTCFs in Iowa from December 2002 through March 2003.

Results:

Of the 429 LTCFs in Iowa, 331 (77%) responded to the survey. The estimated prevalence of residents known to have MRSA was 13.4 per 1,000 and that of residents known to have VRE was 2.3 per 1,000. Facilities owned by the government or those with an average of more than 86 occupied beds were more likely to have residents known to have MRSA and VRE (P = .002 and .007, respectively). Of the responding facilities, 7.3% acknowledged that they refused to accept individuals known to have MRSA and 16.9% acknowledged that they refused to accept those known to have VRE. Facilities in large communities (population, > 100,000) were least likely to deny admission to an individual known to have either MRSA or VRE (P = .05). Most facilities reported adhering to the national guidelines, but fewer than half (44.7%) of the respondents had heard of the Iowa Antibiotic Resistance Task Force's guidelines regarding residents with MRSA or VRE.

Conclusions:

Many LTCFs in Iowa care for residents known to have MRSA or VRE, but some refuse to admit these individuals. Infection control personnel and public health officials should work together to educate LTCF staff so that residents receive proper care and resistant organisms do not spread within this setting.
Succinate-mediated catabolite repression control on the production of glycine betaine catabolic enzymes in Pseudomonas aeruginosa PAO1 under low and elevated salinities
Authors: Diab Farès , Bernard Théophile , Bazire Alexis , Haras Dominique , Blanco Carlos , Jebbar Mohamed
Published: April 2006

Glycine betaine (GB) and its immediate precursors choline and carnitine, dimethylsulfonioacetate, dimethylsulfoniopropionate, ectoine and proline were effective osmoprotectants for Pseudomonas aeruginosa, but pipecolate, trehalose and sucrose had no osmoprotective effect. GB was accumulated stably or transiently when succinate or glucose, respectively, was used as a carbon and energy source. The catabolite repression mediated by succinate occurred at both low and high salinities, and it did not involve the global regulators Vfr and Crc. A proteomic analysis showed that at least 21 proteins were induced when GB was used as a carbon and energy source, and provided evidence that succinate repressed the synthesis of all these proteins. Many of the proteins induced by GB (sarcosine oxidase, serine hydroxymethyltransferase and serine dehydratase) are involved in GB catabolism. In addition, GB uptake was stimulated at high medium osmolalities but it was insensitive to catabolite repression by succinate. Despite its ability to inhibit betaine catabolism, succinate did not allow any better growth of P. aeruginosa cells under hyperosmotic constraint. Conversely, as observed for cells supplied with glucose, a transient accumulation of GB was sufficient to provide a significant cell osmoprotection.
A cyanobacterial strain with all chromosomal rRNA operons inactivated: a single nucleotide mutation of 23S rRNA confers temperature-sensitive phenotypes
Authors: Monshupanee Tanakarn , Fa-aroonsawat Sirirat , Chungjatupornchai Wipa
Published: April 2006

The presence of a multicopy chromosome, with each copy containing two rRNA operons (rrnA and rrnB), has been an obstacle to analysing mutated rRNA in Synechococcus PCC 7942. To create a system for expressing homogeneous mutated rRNA, the chromosomal rrn operons were sequentially inactivated and a final strain was successfully obtained with all the chromosomal rrn operons inactivated but carrying a replaceable multicopy plasmid containing a single rrn operon. The lag time required for growth response on dark/light shift of mutant strains with chromosomal rrnA or rrnB inactivated was increased 50 % over that of the wild-type strain; however, the presence of the plasmid-borne rrn operon restored the lag time. The doubling time of mutant strains carrying only a functional rrnB operon, but not strains carrying only a functional rrnA operon, was significantly longer than that of the wild-type strain. A strain in which essentially all the cellular 23S rRNA contained the mutation C2588A was temperature sensitive at 16 °C and 45 °C. Position C2588 is equivalent to C2611 of the peptidyltransferase centre in domain V of Escherichia coli 23S rRNA.
Graft failure following reduced‐intensity cord blood transplantation for adult patients
Authors: Narimatsu Hiroto , Kami Masahiro , Miyakoshi Shigesaburo , Murashige Naoko , Yuji Koichiro , Hamaki Tamae , Masuoka Kazuhiro , Kusumi Eiji , Kishi Yukiko , Matsumura Tomoko , Wake Atsushi , Morinaga Shinichi , Kanda Yoshinobu , Taniguchi Shuichi
Published: April 2006

We reviewed the medical records of 123 adult reduced‐intensity cord blood transplantation (RI‐CBT) recipients to investigate the clinical features of graft failure after RI‐CBT. Nine (7·3%) had graft failure, and were classified as graft rejection rather than primary graft failure; they showed peripheral cytopenia with complete loss of donor‐type haematopoiesis, implying destruction of donor cells by immunological mechanisms rather than poor graft function. Three of them died of bacterial or fungal infection during neutropenia. Two recovered autologous haematopoiesis. The remaining four patients underwent a second RI‐CBT and developed severe regimen‐related toxicities. One died of pneumonia on day 8, and the other three achieved engraftment. Two of them died of transplant‐related mortality, and the other survived without disease progression for 9·0 months after the second RI‐CBT. In total, seven of the nine patients with graft failure died. The median survival of those with graft failure was 3·8 months (range, 0·9–15·4). Graft failure is a serious complication of RI‐CBT. As host T cells cannot completely be eliminated by reduced‐intensity preparative regimens, we need to be aware of the difficulty in differentiating graft rejection from other causes of graft failure following RI‐CBT. Further studies are warranted to establish optimal diagnostic and treatment strategies.
The effectiveness of an osteoporosis prevention education programme for women in Hong Kong: a randomized controlled trial
Authors: Chan Moon Fai , Ko Chung Ying , Day Mary Christine
Published: April 2006

Aims.  The purpose of this study was to evaluate whether a nurse‐initiated education programme on four specific osteoporosis‐prevention related behaviours leads to their adoption or positive attitude changes compared with women who did not participate in this programme.

Research method.  The design was a randomized controlled design and the setting was a local private beauty clinic.

Outcome measures.  Pre‐, post‐ and follow‐up education data compared attitudes and consumption frequency before and after the education programme.

Results.  The results showed significant increases in the reported follow‐up for each behaviour: consumption of soya foods (mean = 4·3, SD = 0·5), milk (mean = 4·2, SD = 0·8), more exercise (mean = 4·3, SD = 0·5) and vitamin D/exposure to sunlight (mean = 4·2, SD = 0·9) for subjects in the case group compared with control group subjects (soya foods: mean = 3·3, SD = 0·9, P < 0·001; milk: mean = 3·0, SD = 0·9, P < 0·001; more exercise: mean = 3·4, SD = 1·0, P = 0·003; vitamin D/sunlight: mean = 2·7, SD = 0·9, P < 0·00). Most of the participants either disagreed (n = 11, 55·0%) or strongly disagreed (n = 9, 45·0%) that there was not enough information provided in the education programme to motivate them to change. On the satisfaction score, they rated the nurse's performance as either satisfactory (n = 11, 55·0%) or very satisfactory (n = 9, 45·0%) on presentation and ability to answer their questions and either satisfactory (n = 12, 60·0%) or very satisfactory (n = 8, 40·0%) on ability to describe each behaviour clearly.

Conclusion.  A targeted education programme conducted with Hong Kong women resulted in significantly increased consumption of calcium including soya‐based foods, milk and vitamin D. According to the reported attitudinal and behavioural intentions, participants’ positive feedback suggests that women who participated in this educational programme were motivated to make changes and benefited from the support of this nurse‐initiated education programme.

Relevance to clinical practice.  Osteoporosis was a serious health concern that most commonly affected women. As indicated by the results of this study, this educational programme can act as simple but effective nursing intervention to promote women's attitudinal and behavioural intentions towards osteoporosis‐prevention.
Colour stability of porcelain repair materials with accelerated ageing
Authors: SAYGILI G. , ŞAHMALI S. , DEMIREL F.
Published: April 2006

summary  The purpose of this study was to measure and compare the colour stability of three porcelain repair materials (Charizma, Clearfil and Silux Plus) with an all‐ceramic material following accelerated ageing. Three composites and one ceramic control were subjected to accelerated ageing for a period of 300 h. Initial specimen colour parameters were determined in the Commission International de I'Eclairage Lab (CIELAB) colour order system with a colorimeter. Colour changes were calculated before (ΔE) and after 300 h of accelerated ageing (ΔE*). Colour difference data were subjected to one‐way analysis of variance (anova) followed by Duncan's test to examine the interaction between material and time interval of ageing. There were no significant difference between ΔL values of Porcelain‐Charizma and Porcelain‐Silux Plus. All mean ΔL* values were negative after 300 h ageing. Porcelain‐Silux Plus demonstrated the highest ΔL* of the investigated groups. There were significant differences between baseline 300‐h aged specimens with respect to Δa*, Δa for either of the investigated materials. For Silux Plus, Δa and Δa* values were significantly higher than the others. Significant differences were observed between baseline and 300‐h values for Δb and Δb*. Δb and Δb* values were significantly higher for Silux Plus. There were significant differences between baseline and 300‐h values of colour difference, ΔE, ΔE*. Highest ΔE* value was obtained using the microfilled composite, Silux Plus. Lowest value of ΔE was recorded with the hybrid composite, Charizma.
Factors affecting retreat‐site selection by coppertail skinks (Ctenotus taeniolatus) from sandstone outcrops in eastern Australia
Authors: GOLDSBROUGH CLAIRE L. , SHINE RICHARD , HOCHULI DIETER F.
Published: April 2006

Abstract  Coppertail skinks (Ctenotus taeniolatus) are medium‐sized diurnal lizards that are widespread in eastern Australia. Field surveys on sandstone outcrops in the Sydney region showed that these animals use available rocks non‐randomly: coppertails were found under large, sun‐exposed rocks on deep soil. Choice trials in the laboratory documented selection of retreat sites that were warm, with substrate preferences shifting in a diel cycle. Lizards selected retreats with rock substrates during the day but with sandy substrates at night. Rocky retreats attain higher temperatures during daylight hours, but burrows in sand beneath rocks may provide greater protection against ingress by nocturnal predators. During fieldwork we rarely found lizards under rocks with either ants or centipedes, suggesting that coppertails may avoid these predatory invertebrates. Tongue‐flick trials showed that the lizards could discriminate among common ant species based on chemosensory cues, but apparently could not detect centipede chemical cues. In experimental trials, the lizards did not avoid retreat sites scented by either ants or centipedes. Our data thus suggest that retreat‐site selection in coppertails is driven by abiotic cues (rock size, sun exposure and substrate type) that may confer fitness benefits in terms of thermoregulation and predator avoidance, with biotic cues playing a less important role.
Size matters: extraordinary rodent abundance on an Australian tropical flood plain
Authors: MADSEN THOMAS , UJVARI BEATA , SHINE RICHARD , BUTTEMER WILLIAM , OLSSON MATS
Published: April 2006

Abstract:  Published estimates of the total biomass of natural populations of mammalian herbivores generally have ignored small‐bodied taxa (especially, rodents). Including such taxa may dramatically change our understanding of total biomass and energy flow in such systems. Dusky rats (Rattus colletti) are small (up to 210 g) native Australian mammals, and our 5‐year mark‐recapture study on a tropical flood plain (Adelaide River, Northern Territory) revealed that rat biomass can reach extraordinary levels (up to 4.7 t km−2). Because their small body size results in high mass‐specific metabolic rates, a given biomass of rodents has a several‐fold higher total energy requirement than the same mass of large‐bodied herbivores. Accordingly, during some years dusky rat biomass can be double that estimated for large herbivores on the world's most productive savannas in eastern and southern Africa. The huge rodent biomass strongly suggests that the Adelaide River flood plain must be an incredibly productive habitat. Considering the immense biological importance of these productive ecosystems, flood plain conservation must be placed high on the priority list of habitats that require immediate protection.
An Experimental Manipulation of Retrospectively Defined Earned and Continuous Attachment Security
Authors: Roisman Glenn I. , Fortuna Keren , Holland Ashley
Published: April 2006

Recent longitudinal data suggest that retrospectively defined earned‐secures are not more likely than continuous‐secures to have been anxiously attached to their mothers in infancy and indeed experience high‐quality maternal parenting in childhood. Such findings leave unanswered the question of why earned‐secures report negative childhood experiences. On the basis of speculation that earned‐security may result from depression‐related biases in the recall of early experiences, this report describes the effects of an experimental mood induction on the valence of young adults' (18–25 years) life narratives as assessed in the Adult Attachment Interview. Among secure adults, individuals in a sadness condition were more likely to be classified as earned‐secure; happy participants were more likely to be classified as continuous‐secure. Induced mood was unrelated to security versus insecurity.
Mirror Self‐Recognition Beyond the Face
Authors: Nielsen Mark , Suddendorf Thomas , Slaughter Virginia
Published: April 2006

Three studies (N=144) investigated how toddlers aged 18 and 24 months pass the surprise‐mark test of self‐recognition. In Study 1, toddlers were surreptitiously marked in successive conditions on their legs and faces with stickers visible only in a mirror. Rates of sticker touching did not differ significantly between conditions. In Study 2, toddlers failed to touch a sticker on their legs that had been disguised before being marked. In Study 3, having been given 30‐s exposure to their disguised legs before testing, toddlers touched the stickers on their legs and faces at equivalent levels. These results suggest that toddlers pass the mark test based on expectations about what they look like, expectations that are not restricted to the face.
Child Adaptational Development in Contexts of Interparental Conflict Over Time
Authors: Davies Patrick T. , Sturge‐Apple Melissa L. , Winter Marcia A. , Cummings E. Mark , Farrell Deirdre
Published: April 2006

This multi‐method study sought to identify parameters of developmental change and stability of child reaction patterns to interparental conflict in the context of family relations in a sample of 223 6‐year‐old children and their parents followed over the course of one year. Consistent with the sensitization hypothesis, interparental withdrawal and hostility each consistently and uniquely predicted child distress reactions to conflict even after analytically controlling for parental warmth. Associations were found across multiple domains of child responding (i.e., overt negative affect, subjective negative affect, internal representations) and both concurrent and prospective, autoregressive analyses. Results of the autoregressive path analyses indicated moderate stability in each of the domains of conflict reactivity over the 1‐year longitudinal period.
Anaphylaxis: Clinical concepts and research priorities
Authors: Brown Simon GA
Published: April 2006

Anaphylaxis is a severe immediate‐type hypersensitivity reaction characterized by life‐threatening upper airway obstruction bronchospasm and hypotension. Although many episodes are easy to diagnose by the combination of characteristic skin features with other organ effects, this is not always the case and a workable clinical definition of anaphylaxis and useful biomarkers of the condition have been elusive. A recently proposed consensus definition is ready for prospective validation. The cornerstones of management are the supine position, adrenaline and volume resuscitation. An intramuscular dose of adrenaline is generally recommended to initiate treatment. If additional adrenaline is required, then a controlled intravenous infusion might be more efficacious and safer than intravenous bolus administration. Additional bronchodilator treatment with continuous salbutamol and corticosteroids are used for severe and/or refractory bronchospasm. Aggressive volume resuscitation, selective vasopressors, atropine (for bradycardia), inotropes that bypass the β‐adrenoreceptor and bedside echocardiographic assessment should be considered for hypotension that is refractory to treatment. Management guidelines continue to be opinion‐ and consensus‐based, with retrospective studies accounting for the vast majority of clinical research papers on the topic. The clinical spectrum of anaphylaxis including major disease subgroups requires clarification, and validated scoring systems and outcome measures are needed to enable good‐quality prospective observational studies and randomized controlled trials. A systematic approach with multicentre collaboration is required to improve our understanding and management of this disease.
Analysis of Straw by X-ray Photoelectron Spectroscopy
Authors: Jiang Guilin , Husseini Ghaleb A. , Baxter Larry L. , Linford Matthew R.
Published: April 2006

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy (XPS) can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Straw is an example of an agricultural residue (byproduct of food and feed production) of potential interest for biomass combustion. The XPS spectra of straw provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel (C, H, N, S, and O); chlorine analysis — reported here as part of the ultimate analysis but formally a separate procedure; proximate analysis — the proximate composition of the fuel (moisture, fixed carbon, volatiles, and ash); heating value — the specific heat of combustion; ash chemistry analysis — an elemental analysis of the ash content, expressed as oxides (which does not imply that they occur as oxides in the fuel). These data are summarized with the XPS spectra.
The Ability ofMycobacterium aviumsubsp.paratuberculosisTo Enter Bovine Epithelial Cells Is Influenced by Preexposure to a Hyperosmolar Environment and Intracellular Passage in Bovine Mammary Epithelial Cells
Authors: Patel Dilip , Danelishvili Lia , Yamazaki Yoshitaka , Alonso Marta , Paustian Michael L. , Bannantine John P. , Meunier-Goddik Lisbeth , Bermudez Luiz E.
Published: April 2006

Mycobacterium aviumsubsp.paratuberculosisis the cause of Johne's disease in cattle and other ruminants.M. aviumsubsp.paratuberculosisinfection of the bovine host is not well understood; however, it is assumed that crossing the bovine intestinal mucosa is important in order forM. aviumsubsp.paratuberculosisto establish infection. To examine the ability ofM. aviumsubsp.paratuberculosisto infect bovine epithelial cells in vitro, Madin-Darby bovine kidney (MDBK) epithelial cells were exposed toM. aviumsubsp.paratuberculosis. It was observed that bacteria can establish infection and replicate within MDBK cells.M. aviumsubsp.paratuberculosisalso has been reported to infect mammary tissue and milk, and we showed thatM. aviumsubsp.paratuberculosisinfects bovine mammary epithelial cells (MAC-T cell line). Using polarized MAC-T cell monolayers, it was also determined thatM. aviumsubsp.paratuberculosiscrosses apical and basolateral surfaces with approximately the same degree of efficiency. BecauseM. aviumsubsp.paratuberculosiscan be delivered to the naïve host by milk, it was investigated whether incubation ofM. aviumsubsp.paratuberculosiswith milk has an effect on invasion of MDBK cells.M. aviumsubsp.paratuberculosisexposed to milk entered epithelial cells with greater efficiency thanM. aviumsubsp.paratuberculosisexposed to broth medium or water (P< 0.01). Growth ofM. aviumsubsp.paratuberculosiswithin MAC-T cells also resulted in augmented ability to subsequently infect bovine MDBK cells (P< 0.001). Microarray analysis of intracellularM. aviumsubsp.paratuberculosisRNA indicates the increased transcription of genes which might be associated with an invasive phenotype.
Levels of Plasma Immunoglobulin G with Specificity against the Cysteine-Rich Interdomain Regions of a SemiconservedPlasmodium falciparumErythrocyte Membrane Protein 1, VAR4, Predict Protection against Malarial Anemia and Febrile Episodes
Authors: Lusingu John P. A. , Jensen Anja T. R. , Vestergaard Lasse S. , Minja Daniel T. , Dalgaard Michael B. , Gesase Samwel , Mmbando Bruno P. , Kitua Andrew Y. , Lemnge Martha M. , Cavanagh David , Hviid Lars , Theander Thor G.
Published: April 2006

Antibodies to variant surface antigen have been implicated as mediators of malaria immunity in studies measuring immunoglobulin G (IgG) binding to infected erythrocytes.Plasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) is an important target for these antibodies, but no study has directly linked the presence of PfEMP1 antibodies in children to protection. We measured plasma IgG levels to the cysteine-rich interdomain region 1α (CIDR1α) of VAR4 (VAR4-CIDR1α), a member of a semiconserved PfEMP1 subfamily, by enzyme-linked immunosorbent assay in 561 Tanzanian individuals, who were monitored clinically for 7 months. The participants resided in Mkokola (a high-transmission village where malaria is holoendemic) or Kwamasimba (a moderate-transmission village). For comparison, plasma IgG levels to two merozoite surface protein 1 (MSP1) constructs, MSP1-19 and MSP1 block 2, and a control CIDR1 domain were measured. VAR4-CIDR1α antibodies were acquired at an earlier age in Mkokola than in Kwamasimba, but after the age of 10 years the levels were comparable in the two villages. After controlling for age and other covariates, the risk of having anemia at enrollment was reduced in VAR4-CIDR1α responders for Mkokola (adjusted odds ratio [AOR], 0.49; 95% confidence interval [CI], 0.29 to 0.88;P =0.016) and Kwamasimba (AOR, 0.33; 95% CI, 0.16 to 0.68;P= 0.003) villages. The risk of developing malaria fever was reduced among individuals with a measurable VAR4-CIDR1α response from Mkokola village (AOR, 0.51; 95% CI, 0.29 to 0.89;P= 0.018) but not in Kwamasimba. Antibody levels to the MSP1 constructs and the control CIDR1α domain were not associated with morbidity protection. These data strengthen the concept of developing vaccines based on PfEMP1.
Immunoglobulin G Antibodies to Merozoite Surface Antigens Are Associated with Recovery from Chloroquine-ResistantPlasmodium falciparumin Gambian Children
Authors: Pinder Margaret , Sutherland Colin J. , Sisay-Joof Fatoumatta , Ismaili Jamila , McCall Matthew B. B. , Ord Rosalyn , Hallett Rachel , Holder Anthony A. , Milligan Paul
Published: April 2006

We examined the hypothesis that recovery from uncomplicated malaria in patients carrying drug-resistantPlasmodium falciparumis a measure of acquired functional immunity and may therefore be associated with humoral responses to candidate vaccine antigens. Gambian children with malaria were treated with chloroquine in 28-day trials, and recovery was defined primarily as the absence of severe clinical malaria at any time and absence of parasitemia with fever after 3 days. Plasma samples from these children were assayed by enzyme-linked immunosorbent assay for immunoglobulin G (IgG) to recombinant merozoite antigens: apical membrane antigen 1 (AMA-1) and the 19-kDa C-terminal region of merozoite surface protein 1 (MSP-119), including antigenic variants of MSP-119with double and triple substitutions. Antigen-specific IgG was more frequent in children who recovered, particularly that for MSP-119(age-adjusted odds ratios: 0.32 [95% confidence interval, 0.05, 1.87;P= 0.168] for AMA-1, 0.19 [0.03, 1.11;P= 0.019] for recombinant MSP-119, 0.24 [0.04, 1.31;P= 0.032] for the recombinant MSP-119double variant, and 0.18 [0.03, 0.97;P= 0.013] for the triple variant). IgG titers to MSP-119and to the triple variant were higher in plasma samples taken 7 days after chloroquine treatment from children who carried resistant parasites but recovered and remained parasite free. Moreover, in children who were parasitemic on day 14 or day 28, there was an age-independent relationship between parasite density and IgG to both MSP-119and the triple variant (coefficients of −0.550 and −0.590 andPvalues of 0.002 and 0.001, respectively). The results validate the use of this approach to identify antigens that are associated with protection from malaria.
Regulation of RraA, a Protein Inhibitor of RNase E-Mediated RNA Decay
Authors: Zhao Meng , Zhou Li , Kawarasaki Yasuaki , Georgiou George
Published: April 2006

The recently discovered RraA protein acts as an inhibitor of the essential endoribonuclease RNase E, and we demonstrated that ectopic expression of RraA affects the abundance of more than 700 transcripts inEscherichia coli(K. Lee, X. Zhan, J. Gao, J. Qiu, Y. Feng, R. Meganathan, S. N. Cohen, and G. Georgiou, Cell 114:623-634, 2003). We show thatrraAis expressed from its own promoter, PrraA, located in themenA-rraAintergenic region. Primer extension andlacZfusion analysis revealed that transcription from PrraAis elevated upon entry into stationary phase in a σs-dependent manner. In addition, the stability of therraAtranscript is dependent on RNase E activity, suggesting the involvement of a feedback circuit in the regulation of the RraA level inE. coli.