Default operational intervention levels (OILs) for severe nuclear power plant or spent fuel pool emergencies.

Experience and studies show that for an emergency at a nuclear power plant involving severe core damage or damage to the fuel in spent fuel pools, the following actions may need to be taken in order to prevent severe deterministic health effects and reduce stochastic health effects: (1) precautionary protective actions and other response actions for those near the facility (i.e., within the zones identified by the International Atomic Energy Agency) taken immediately upon detection of facility conditions indicating possible severe damage to the fuel in the core or in the spent fuel pool; and (2) protective actions and other response actions taken based on environmental monitoring and sampling results following a release. This paper addresses the second item by providing default operational intervention levels [OILs, which are similar to the U.S. derived response levels (DRLs)] for promptly assessing radioactive material deposition, as well as skin, food, milk and drinking water contamination, following a major release of fission products from the core or spent fuel pool of a light water reactor (LWR) or a high power channel reactor (RBMK), based on the International Atomic Energy Agency's guidance.

Phonological awareness and early reading development in childhood apraxia of speech (CAS).

BACKGROUND: Childhood apraxia of speech (CAS) is associated with phonological awareness, reading, and spelling deficits. Comparing literacy skills in CAS with other developmental speech disorders is critical for understanding the complexity of the disorder. AIMS: This study compared the phonological awareness and reading development of children with CAS and children with inconsistent speech disorder (ISD). METHOD & PROCEDURES: Participants included twelve children with CAS aged 4-7 years. Their performance was compared with twelve children with ISD (and normal speech motor planning) and twelve children with typical development on tasks measuring phonological awareness, letter-sound knowledge, real and non-word decoding, and access to underlying phonological representations of words. There was no significant difference in the age, gender, socio-economic status, and receptive vocabulary of the groups. The two groups with speech disorder were matched for severity and inconsistency of their speech impairment. OUTCOMES & RESULTS: The results indicated that the CAS group had inferior phonological awareness than the ISD and typical development groups. The CAS group had a greater proportion of participants performing below their expected age level than the comparison groups on phonological awareness, letter-sound knowledge and decoding tasks. There was no difference in the performance of the CAS and ISD groups on the phonological representation task. CONCLUSIONS & IMPLICATIONS: Children with CAS are particularly susceptible to phonological awareness and reading delay. Intervention for children with CAS must facilitate skills underlying reading development in addition to resolving speech deficits in order to improve the spoke and written language outcomes of this population.

Soil microorganisms determine the sorption of radionuclides within organic soil systems.

The potential of soil microorganisms to enhance the retention of (137)Cs and (85)Sr in organic systems was assessed in a series of experiments. A biologically active, 'mineral-free', organic material, produced under laboratory conditions from leaves, was used as the uptake matrix in all experiments to minimise potential interference from competing clay minerals. Biological uptake and release were differentiated from abiotic processes by comparing the sorption of radionuclides in sterilised organic material with sterile material inoculated with soil extracts or single fungal strains. Our results show conclusively that living components of soil systems are of primary importance in the uptake of radionuclides in organic material. The presence of soil microorganisms significantly enhanced the retention of Cs in organic systems and approximately 70% of the Cs spike was strongly (irreversibly) bound (remained non-extractable) in the presence of microorganisms compared to only approximately 10% in abiotic systems. Sorption of (85)Sr was not significantly influenced by the presence of soil microorganisms. A non-linear temperature response was observed for the retention in biotic systems with increased uptake at between 10 and 30 degrees C and lower retention at temperatures above or below the optimum range. The optimum temperatures for biological uptake were between 15 and 20 degrees C for Cs, and 25 and 30 degrees C for Sr. Our results indicate that single strains of soil and saprotrophic fungi make an important contribution to the sorption of Cs and Sr in organic systems, but can only account for part of the strong, irreversible binding observed in biotic systems. Single strains of soil fungi increased the amount of non-extractable (137)Cs (by approximately 30%) and (85)Sr (by approximately 20%) in the organic systems as compared to abiotic systems, but the major fraction of (137)Cs and (85)Sr sorbed in systems inoculated with saprotrophic fungi remained extractable.

Education for practice in the UK and Ireland: implementing problem-based learning.

OBJECTIVE: This paper outlines the education of speech and language therapists in the UK and Ireland, and presents a preliminary study of student therapists' perceptions of problem-based learning (PBL) as a learning strategy in preparation for clinical work. PBL has been used extensively in medical and dental education in Europe, in Canada, and in the Middle East, and has been applied to speech and language therapist education in Sweden and in Australia. Its implementation in the UK and Ireland is relatively new. METHODS: A survey questionnaire was circulated to students in two centres via e-mail. Questions posed included student impressions of the most and least useful elements of PBL in their preparation for clinical practice, as well as how they considered improvements could be made; student reflections regarding PBL were also sought. RESULTS AND CONCLUSIONS: Findings support the implementation of PBL in the education of speech and language therapists, with more experienced students showing more positive support for PBL. Issues raised by the study include emphasis on clinical relevance of problems, particularly in the early years of the course. The majority of students regarded PBL as directly relevant for clinical preparation.

Modelling the role of humic acid in radiocaesium distribution in a British upland peat soil.

The significance of exchange sites on organic matter in the retention of radiocaesium in highly organic soils remains unclear. To quantify this retention, we measured the binding of 134Cs to a humic acid isolated from a British upland peat soil, under a range of chemical conditions. We interpreted our results using Humic Ion Binding Model V, a model of humic substance chemistry which simulates ion exchange by non-specific accumulation of cations adjacent to the humic molecules. Model V could simulate the humic acid-solution partitioning of Cs under all the solution conditions used. The model was used to estimate the contribution of organic matter to Cs sorption by the whole soil composite. An estimate of Cs sorption by illite frayed edge sites was also made. These simulations show that organic matter may play only a minor role in binding Cs. even in highly organic soils.

Speech disorder in children with Down's syndrome.

The speech of children with Down's syndrome (DS) is often unintelligible, unlike many other children who have an intellectual disability. However, the nature of their speech disorder is controversial. The speech error patterns of children with DS were compared to those of intellectually average children with phonological disorder whose errors were characterized by inconsistency. The groups were matched for percentages of consonants produced in error. The data revealed no differences between the groups in terms of the number of words which were produced inconsistently on repeated productions in a picture-naming task. However, further analyses revealed differences in the type of errors made by the groups in that the children with phonological disorder characterized by inconsistent errors made more changes to words on repeated production than the group with DS. The deficits underlying inconsistent pronunciation of words in the two groups of children under investigation would appear to differ. Intervention strategies should target the deficits identified.

Mainstream paediatric speech and language therapy service population: epidemiology.

The epidemiology of 1090 referrals to a mainstream paediatric speech and language therapy department over fifteen months is discussed, in relation to referral information and initial detailed assessment. Clients are classified by their main presenting difficulty and by their degree of severity. This information will inform clinicians of the nature of the caseload of a typical inner city service which will, in turn, aid service planning.

Comparison of cross-language generalisation following speech therapy.

Little is known about the phonological development of children who acquire two languages sequentially in the preschool years. Some of these children will be referred for assessment of speech disorder. Distinguishing between delayed development due to the language learning environment and disorder is problematic in the absence of normative data on the typical phonological development of bilingual children. Another major issue concerns whether both languages require intervention, or only one because of generalisation to the other language. Treatment efficacy studies of 2 bilingual children are reported. The data indicate that different patterns of cross-language generalisation occur depending upon the deficit in the speech processing chain underlying the speech disorder.

Phonological systems of a set of Putonghua-speaking twins.

Impaired phonology is reported to be the most salient characteristic of the communication profiles of twin children. However, little is known about the phonological development of twins speaking languages other than English. This case study described the phonological systems of a set of Putonghua-speaking twins, using quantitative and qualitative measures. The analyses indicated that the phonological systems of the co-twins were not identical, though both evidenced characteristics of delayed or disordered phonological development and shared some error patterns. They comprehended both adult and their sibling's phonological forms, suggesting a dual phonological representation in their mental lexicon for some words. These results confirmed Dodd and McEvoy's (1994) research findings for English-speaking twins.

A comparison of three therapy methods for children with different types of developmental phonological disorder.

Treatment case studies of three children whose speech was characterized by non-developmental errors are described. Three therapy methods were trialed with each child: phonological contrast; core vocabulary and PROMPT. The accuracy and intelligibility of the children's connected speech improved throughout the course of the programme. Intervention that focused on teaching a rule about the contrastive use of phonemes was most successful for a child who consistently made non-developmental errors. Children making inconsistent errors received most benefit from the core vocabulary approach that markedly enhanced consistency of production. However, once consistency was established, one child benefited from phonological contrast therapy. While the results of the study should be interpreted with caution due to the small sample size and the cumulative effects of intervention, the findings suggest that different parts of a child's phonological and phonetic system may respond to various types of treatment approaches that target different aspects of speech production. The implication drawn is that just as no single treatment approach is appropriate for all children with disordered phonology, management of some children may involve selecting and sequencing a range of different approaches.

The perceptual magnet effect in Australian English vowels.

Recent research (Kuhl, 1991) has suggested that the internal structure of vowel categories is graded in terms of stimulus goodness. It has been proposed that a best instance stimulus reflects a central point or prototype, which effectively renders within-category members perceptually more similar. Discrimination experiments suggest a nonlinear relationship between acoustic and perceptual space near category centers (Iverson & Kuhl, 1995b). This phenomenon has been described as the perceptual magnet effect. The present study investigated the presence of the perceptual magnet effect in five Australian vowel categories. Australian English speakers identified, rated, and discriminated between a pool of 32 vowel stimuli that varied in F1 and F2 values. The results from Experiments 1 and 2 showed that subjects were able to judge the quality and identify of each stimulus and that a general grading of stimulus quality was reported. This was not symmetrical, and the subjects' responses varied considerably. In Experiment 3, closer control of the methodology in the discrimination task and of contextual factors influencing the test materials was exercised. Despite this, evidence of the warping of perceptual space in discrimination data was not found. In general, these results do not provide support for the existence of the perceptual magnet effect, and explanations for this finding are discussed.

The phonological acquisition of Putonghua (Modern Standard Chinese).

The phonological acquisition of 129 monolingual Putonghua-speaking children, aged 1;6 to 4;6, is described. Putonghua (Modern Standard Chinese) syllables have four possible elements: tone, syllable-initial consonant, vowel, and syllable-final consonant. The children's errors suggested that Putonghua-speaking children mastered these elements in the following order: tones were acquired first; then syllable-final consonants and vowels; and syllable-initial consonants were acquired last. Phonetic acquisition of the 21 syllable-initial consonants was complete by 3;6 for 75% of children. By 4;6 the children were using the syllable-initial consonants correctly on two thirds of occasions (with the exception of four affricates). Simple vowels emerged early in development. However, triphthongs and diphthongs were prone to systematic errors. Tone errors were rare, perhaps because of their role in distinguishing lexical meaning. In contrast, acquisition of 'weak stress' and 'rhotacized feature' was incomplete in the oldest children assessed. Phonological processes used by the children were identified. Two of these processes, syllable-initial consonant deletion and backing, would be considered atypical error patterns in English. Existing theories of phonological acquisition (e.g. concepts of markedness, functional load, feature hierarchies) cannot account for some of the patterns revealed. A satisfactory explanation of the findings requires more attention to the specific characteristics of the linguistic system the children are learning. It is proposed that the saliency of the components in the language system determines the order of acquisition.

Radiocaesium activity concentrations in the fruit-bodies of macrofungi in Great Britain and an assessment of dietary intake habits.

Radiocaesium activity concentrations in the fruit-bodies of some species of macrofungi are higher than in many other foodstuffs. The consumption of fruit-bodies contributes significantly to radiocaesium intake of humans in some countries. In the United Kingdom, the collection of wild fungi has generally been considered to be of minor importance and there are few data on consumption rates or radiocaesium activity concentrations in most edible species. Samples of commonly eaten species in Great Britain have been collected to assess radiocaesium contamination levels and geographical variation. Concurrently, surveys of consumption habits were conducted. A total of 425 samples representing 37 different species were collected. Significantly higher radiocaesium activity concentrations occurred in mycorrhizal compared to saprotrophic or parasitic species. The highest 137Cs activity concentration of 30.5 kBq kg-1 dry wt. was determined in a sample of Hydnum repandum collected in Wales. The transfer of radiocaesium from soil to fungal fruit-bodies was highly variable, ranging over three orders of magnitude within individual species. A number of approaches to quantifying radiocaesium transfer from soil to fungal fruit-bodies were used. Although these were in general agreement with previously measured values in other countries, all the approaches gave variable results. Over 200 people responded to the dietary habits questionnaire. The median intake rate was 0.75 kg year-1 (fresh wt.) and 60% of respondents consumed only one species (generally Agaricus campestris). However, intakes of up to 26 kg year-1 were recorded and a total of 82 species were consumed. The intake of 137Cs was determined by the amount of mycorrhizal fungi in the diet rather than the total intake of fungi. Assuming median recorded 137Cs activity concentrations in each fungal species, the estimated annual committed effective dose for over 95% of respondents was < 1 microSv. Hence, currently, the consumption of wild fungi in the UK would not be expected to significantly increase the dose above that attributable to the normal diet of most consumers. However, the results of this study demonstrate that, in the event of any future accidental release of radiocaesium, the potential ingestion dose received from the consumption of wild fungi would need to be considered.

Parameter recovery for the rating scale model using PARSCALE.

The purpose of the present study was to investigate item and trait parameter recovery for Andrich's rating scale model using the PARSCALE computer program. The four factors upon which the simulated data matrices varied were (a) the distribution of the scale values for the items (skewed or uniform), (b) the number of category response options (4 or 5), (c) the distribution of known trait levels (normal or skewed), and (d) the sample size (60, 125, 250, 500, or 1,000). Each condition was replicated 10 times resulting in 400 data matrices. Accurate item and trait parameter estimates were obtained for all sample sizes examined. As expected, sample size seemed to have little influence on the recovery of trait parameters but did influence item parameter recovery. The distribution of known trait levels did not seriously impact the item parameter recovery. It was concluded that Andrich's rating scale model allows for the use of considerably smaller calibration samples than are typically recommended for other polytomous IRT models.

A comparison of three polytomous item response theory models in the context of testlet scoring.

An alternative to dichotomous scoring of multiple items anchored to a common stem is scoring these items as a single polytomous item (testlet scoring). This study systematically compared the partial credit model (PCM), the generalized partial credit model (GPCM), and the graded response model (GRM) in the context of testlet scoring. Data sets included a sample from the fall 1994 administration of the SAT I (N = 2,548) and a simulated data set. Theta estimation, information, and model fit were analyzed. Correlations among theta estimates ranged from 0.9748 to 0.9921. The relationship among the information functions of the PCM, GPCM and the GRM reflected the discrimination parameter estimates for the latter two models. Suggestions are made with regard to model selection.

Phonological awareness skills of 4-year-old British children: an assessment and developmental data.

This study reports developmental data for the phonological awareness and processing skills of 57 normally developing Tyneside preschool children, aged between 46 and 58 months. The children were assessed on eight tasks: consistency of word production, phonological variability according to speech production task, non-word imitation, syllable segmentation, rhyme awareness, alliteration awareness, phoneme isolation and phoneme segmentation. The results indicated that girls and boys performed similarly; socio-economic status significantly affected performance on six of the tasks; and age was significantly correlated with performance on tasks targeting alliteration, non-word imitation, phonological variability, and phoneme isolation and segmentation. The older children were more phonologically aware than the younger children.