Stratified coastal ocean interactions with tropical cyclones.

Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward.

Advances in x-ray framing cameras at the National Ignition Facility to improve quantitative precision in x-ray imaging.

We describe an experimental method to measure the gate profile of an x-ray framing camera and to determine several important functional parameters: relative gain (between strips), relative gain droop (within each strip), gate propagation velocity, gate width, and actual inter-strip timing. Several of these parameters cannot be measured accurately by any other technique. This method is then used to document cross talk-induced gain variations and artifacts created by radiation that arrives before the framing camera is actively amplifying x-rays. Electromagnetic cross talk can cause relative gains to vary significantly as inter-strip timing is varied. This imposes a stringent requirement for gain calibration. If radiation arrives before a framing camera is triggered, it can cause an artifact that manifests as a high-intensity, spatially varying background signal. We have developed a device that can be added to the framing camera head to prevent these artifacts.

Methods for characterizing x-ray detectors for use at the National Ignition Facility.

Gated and streaked x-ray detectors generally require corrections in order to counteract instrumental effects in the data. The method of correcting for gain variations in gated cameras fielded at National Ignition Facility (NIF) is described. Four techniques for characterizing the gated x-ray detectors are described. The current principal method of characterizing x-ray instruments is the production of controlled x-ray emission by laser-generated plasmas as a dedicated shot at the NIF. A recently commissioned pulsed x-ray source has the potential to replace the other characterization systems. This x-ray source features a pulsed power source consisting of a Marx generator, capacitor bank that is charged in series and discharged in parallel, producing up to 300 kV. The pulsed x-ray source initially suffered from a large jitter (∼60 ns), but the recent addition of a pulsed laser to trigger the spark gap has reduced the jitter to ∼5 ns. Initial results show that this tool is a promising alternative to the other flat fielding techniques.

Crosstalk in x-ray framing cameras: Effect on voltage, gain, and timing (invited).

We present evidence that electromagnetic crosstalk between independent strips in gated x-ray framing cameras can affect relative gains by up to an order of magnitude and gate arrival times up to tens of picoseconds when strip separation times are less then ∼1 ns. Crosstalk is observed by multiple methods, and it is confirmed by direct measurements of voltage on the active surface of the detector and also by indirect voltage monitors in routine operation. The voltage measurements confirm that crosstalk is produced not only in the active regions of the microchannel plate, but also along the entire input path of the voltage pulses.

Extracting core shape from x-ray images at the National Ignition Facility.

Measuring the shape of implosions is critical to inertial confinement fusion experiments at the National Ignition Facility. We have developed techniques that have proven successful for extracting shape information from images of x-ray self-emission recorded by a variety of diagnostic instruments for both DT-filled targets and low-yield surrogates. These key results help determine optimal laser and target parameters leading to ignition. We have compensated for instrumental response and have employed a variety of image processing methods to remove artifacts from the images while retaining salient features. The implosion shape has been characterized by decomposing intensity contours into Fourier and Legendre modes for different lines of sight. We also describe procedures we have developed for estimating uncertainties in these measurements.

Direct measurement of energetic electrons coupling to an imploding low-adiabat inertial confinement fusion capsule.

We have imaged hard x-ray (>100 keV) bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. We measure 570 J in electrons with E>100 keV impinging on the fusion capsule under ignition drive conditions. This translates into an acceptable increase in the adiabat α, defined as the ratio of total deuterium-tritium fuel pressure to Fermi pressure, of 3.5%. The hard x-ray observables are consistent with detailed radiative-hydrodynamics simulations, including the sourcing and transport of these high energy electrons.

Physical activity and psychological well-being in children with Type 1 diabetes.

Physical activity and psychological well-being contribute to positive lifestyle and well-being in youngsters who have Type 1 diabetes. The aims of this study were to objectively assess the physical activity levels of children with Type 1 diabetes, and investigate associations between physical activity levels, psychological well-being and HbA(1c). Thirty-six children, mean age 12.8 years, participated in the investigation. Physical activity was assessed using heart rate monitoring over four days. Children further completed the Diabetes Quality of Life for Youths Questionnaire, the Physical Self-Perception Profile for Children and the Self-Efficacy for Diabetes Scale. Routine outpatient HbA(1c) measurements were recorded. There were no significant associations between psychological well-being and physical activity, or HbA(1c) and physical activity, thus suggesting physical activity does not directly relate to psychological well-being in children with Type 1 diabetes. It may be that the effect of physical activity differs from that in children without Type 1 diabetes because of the place of physical activity within diabetes management and the need to balance this with insulin dosage and dietary intake to maintain blood glucose levels.

Additional therapy for young children with spastic cerebral palsy: a randomised controlled trial.

OBJECTIVES: To investigate whether, in the short and medium term, additional support by (a) a physiotherapy assistant improved physical function in young children with spastic cerebral palsy and (b) a family support worker improved family functioning. DESIGN: This was a multi-centre randomised controlled trial (RCT) with blinded assessments and a cost-effectiveness analysis. The children studied had spastic cerebral palsy that was the consequence of perinatal adversity. All were less than 4 years old on entry to the study. SETTING: In the child development centre and in the home. PARTICIPANTS: Seventy-six families completed the intervention period. Forty-three families were reassessed 6 months after the end of the intervention and 34 of these after a further 6-month period. INTERVENTIONS: Randomisation was to: (a) a group who received extra physiotherapy from a physiotherapy assistant; (b) a group who received standard physiotherapy; and (c) a group where the child received standard physiotherapy and the family was also visited by a family support worker. Children in all groups continued to receive standard physiotherapy in addition to the study interventions. MAIN OUTCOME MEASURES: The child outcome measures were motor functioning, developmental status and adaptive functioning. The family outcome measures were self-reported maternal stress, level of family needs and parental satisfaction. RESULTS: There was no evidence that additional physical therapy for 1 hour per week for 6 months by a physiotherapy assistant improved any child outcome measure in the short or medium term. Intervention by a family support worker did not have a clinically significant effect on parental stress or family needs. Over the 6-month period the total cost of services for each child ranged from 250 pounds to 6750 pounds, with higher costs associated with children with more severe impairments. No significant relationship was found between measures of intensity of services received by the children and families and the main outcome measures. Low-functioning children, in terms of both motor and cognitive function, were more likely to receive more services in terms of range and frequency. Parents generally reported high satisfaction ratings after all interventions and some stated that the interventions had benefited the child and/or the family. There was therefore a discrepancy between the perceptions of these parents and the objective, quantitative measurements. The family support workers identified a small number of families who were experiencing considerable family problems, but who had not been referred for appropriate support by any other agency. CONCLUSIONS: The findings of this study provide support for the current literature that there was no evidence that additional intervention (in this case by a physiotherapy assistant or family support worker) helped the motor or general development of young children with spastic cerebral palsy. Nor was there any quantitative evidence that providing extra family support helped levels of parental stress and family needs. The implication was that the provision of extra physical therapy does not necessarily improve the motor function of a young child with cerebral palsy and additional family support should not automatically be assumed to be beneficial. In addition, no significant association was found between the intensity of the local services provided and any outcome measure, other than a slight association with lowered family needs. The provision of local services was related to the severity of the child's impairments and not to family difficulties. A small group of families with complex family problems needed more service input. There was a wide range in the costs of services. Research is needed to examine what 'sufficient' levels of provision or therapy might be for which children and which families. A time series of different levels of input and outcomes would provide valuable information for practitioners. It is also recommended that future assessments of therapies of this type adopt a similar multifaceted approach, which is likely to be more suitable than a simple RCT for the evaluation of clinical interventions where the effects are complex. The most appropriate measures of outcome should be used, including assessment of provision of information and emotional support for families.

Comparison of the 1969 and 1993 standardizations of the Bayley Mental Scales of Infant Development for infants with Down's syndrome.

The Bayley Scales of Infant Development (BSID) were re-standardized in 1993 (BSID-II). The present study reports a comparison of the two versions with infants with Down's syndrome (DS). The BSID-II was used for 93 assessments of 54 children with DS (age range = 7-43 months). Comparisons were made with the 1969 standardization for 42 of these assessments, and for 45 assessments of 20 typically developing children aged between 6 and 24 months. The 1993 standardization produced significantly lower mean differences of 1.0 months mental age and 8.4 points mental development index for infants with DS, and 1.5 months mental age and 9.2 points mental development index for the typically developing group. Nineteen per cent more infants with DS had scores below two standard deviations and there was a larger decrement for lower functioning children. Both groups of children have to perform at a higher level to achieve the same relative score on BSID-II compared to BSID. This indicates that caution should be used in comparing cohorts of children tested on different versions of the Bayley scales. In addition, concerns are highlighted regarding the rules for establishing basal and ceiling levels for BSID-II for children with developmental delays.

Parents' reports of young people with Down syndrome talking out loud to themselves.

Despite parental concerns about young people with Down syndrome talking out loud to themselves (using private speech), there is virtually no research literature on this behavior. In that which exists, investigators have largely interpreted the behavior within a pathological framework. An alternative perspective is that self-talk is developmentally appropriate for these young people. Parents of 78 young people with Down syndrome, age 17 to 24 years, were asked whether their offspring had ever used private speech. Results confirm the universality of private speech and its developmental pattern. No association was found between private speech and behavior problems, communication difficulties, or social isolation. Talking out loud to self by young people with Down syndrome should be seen as adaptive, and not an indication of pathology.

The effect of intensity of training on sensori-motor development in infants with Down's syndrome.

Twenty-four children with Down's syndrome involved in an early intervention programme were divided into matched intensive training (ITG) and control groups (CG), at a mean age of 42 weeks. Parents of children in the ITG were given exercises to carry out daily to train object permanence, imitation and span of attention. Parents of children on the CG were given general advice. All children were assessed on check lists in the three areas and on standard developmental tests. Results showed small short-term effects in favour of the ITG during the training but no long-term effects on development. It was suggested that the short-term effects were mainly due to improved stability of performance in the ITG.

Mental ability, symbolic play and receptive and expressive language of young children with Down's syndrome.

The relationship between measures of mental ability, symbolic play and expressive and receptive language was investigated in a sample of 73 children with Down's syndrome (mean CA 48.9 months, range 19-90 months; mean MA 30.4 months, range 13-73 months). Language delay became increasingly apparent with age, and more so in boys than girls. There was no significant difference between mental ages derived from standard ability tests and corresponding age equivalent scores of the Lowe and Costello symbolic play test. A developmental progression of play similar to that seen in non-handicapped groups was found. However, it is suggested that the use of a more detailed scoring system would be informative.

Selective auditory preferences and the use of automated equipment by severely, profoundly and multiply handicapped children.

Using automated equipment, contingent responding and auditory preferences were examined in 15 severely, profoundly and multiply handicapped children (CMAs 3-20 months) and 2 non-handicapped children at ages 5.0 and 9.5 months. 15 children showed contingent responding; prolonged responding was shown by the profoundly handicapped group. Where auditory preferences were apparent, they were the same as those seen in Down's syndrome and non-handicapped groups at the same developmental level. Children at the 5 months developmental level and less, had difficulty in making choice responses. Implications for intervention are discussed.

Recognition of the familiar words of nursery rhymes by handicapped and non-handicapped infants.

Nine infants with Down's syndrome (mean MA, 9.1 months), seven non-handicapped infants (mean MA, 9.6 months) and one severely handicapped infant (MA, 9.5 months) were given the choice of listening to familiar nursery rhymes or to the same rhymes with each word reversed such that the rhythms, intonation and stress patterns were kept intact but the words were nonsense. Six infants with Down's syndrome, five non-handicapped infants and the severely handicapped infant had significant preferences for the familiar rhymes, and the strength of this preference increased with increasing mental age. The results suggest that both handicapped and non-handicapped infants are beginning to recognise familial words of nursery rhymes at this age. The relevance of the results for early intervention procedures is discussed.

A study of auditory preferences in nonhandicapped infants and infants with Down's syndrome.

11 infants with Down's syndrome (MA 9.2 months, CA 12.7 months) and 10 of 11 nonhandicapped infants (MA 9.6 months, CA 9.3 months) demonstrated that they could operate an automated device which enabled them to choose to listen to 1 of a pair of auditory signals. All subjects showed preferential responding. Both groups of infants showed a significant preference for nursery rhymes sung by a female voice rather than played on musical instruments. The infants with Down's syndrome had much longer response durations for the more complex auditory stimuli. The apparatus provides a useful technique for studying language development in both normal and abnormal populations.