Do two and three year old children use an incremental first-NP-as-agent bias to process active transitive and passive sentences? : A permutation analysis

We used eye-tracking to investigate if and when children show an incremental bias to assume that the first noun phrase in a sentence is the agent (first-NP-as-agent bias) while processing the meaning of English active and passive transitive sentences. We also investi-gated whether children can override this bias to successfully distinguish active from passive sentences, after processing the remainder of the sentence frame. For this second question we used eye-tracking (Study 1) and forced-choice pointing (Study 2). For both studies, we used a paradigm in which participants simultaneously saw two novel actions with reversed agent-patient relations while listening to active and passive sentences. We compared English-speaking 25-month-olds and 41-month-olds in between-subjects sentence struc-ture conditions (Active Transitive Condition vs. Passive Condition). A permutation analysis found that both age groups showed a bias to incrementally map the first noun in a sentence onto an agent role. Regarding the second question, 25-month-olds showed some evidence of distinguishing the two structures in the eye-tracking study. However, the 25-month-olds did not distinguish active from passive sentences in the forced choice pointing task. In contrast, the 41-month-old children did reanalyse their initial first-NP-as-agent bias to the extent that they clearly distinguished between active and passive sentences both in the eye-tracking data and in the pointing task. The results are discussed in relation to the development of syntactic (re)parsing

Respiratory function in patients with thalassaemia and iron overload

Iron deposition in the respiratory system has been proposed as a potential cause of the ventilatory restrictive impairment seen in patients with thalassaemia major (TM) and iron overload. In this study, magnetic resonance imaging (MRT) measurements of the liver (T2 relaxation time) were used as a surrogate index of total body iron burden and the extent to which these measurements correlated with total lung capacity (TLC) in patients with TM was examined. Twenty-one patients (aged 25+/-5 yrs) with TM participated in the study. Standard pulmonary function tests were undertaken and the T2 relaxation time of the liver was measured in all patients. Ventilatory restrictive impairment (mean TLC 74+/-11 (SD)% predicted) was the most common abnormality found in 71% of TM patients. There was no correlation between TLC (% pred) and T2 relaxation time (r=0.06, p=0.78). T2 relaxation time correlated weakly with average serum ferritin Levels (r=-0.56, p=0.008). In conclusion, the data do not support the notion that the restrictive impairment in patients with thalassaemia major and iron overload is related to iron deposition in the respiratory system

Detection of malignant bone marrow involvement with dynamic contrast-enhanced magnetic resonance imaging

Background: The purpose of this study was to evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (dMRI) in detecting bone marrow involvement in cancer patients. Patients and methods: We studied 50 consecutive patients with histologically confirmed malignant dissemination to the bone marrow, using dMRI of the lumbosacral spine. Time-signal intensity curves were generated from regions of interest (ROIs) obtained from areas of obvious bone marrow disease (group B). In 16 patients from group B with focal disease, ROIs were also placed on areas with apparently normal bone marrow on static magnetic resonance images (group C). Twenty-two patients with no history of malignancy were used as a control group (group A). Wash-in (WIN) and wash-out (WOUT) rates, time to peak (TTPK), time to maximum slope (TMSP) values and WIN/TMSP ratios were calculated for each patient. Mean values for the three groups were compared statistically. Six patients from group B had follow-up dMRI after chemotherapy: four patients achieved a clinical partial response and two had resistant disease. Results: A significant difference was found between groups A and B for all values. Between groups A and C, in spite of the similar static MRI appearance, all values were significantly different. Between groups B and C, a significant difference was found for WIN, WOUT rates and WIN/TMSP ratio. Follow-up dMRI data analysis correlated well with clinical staging. Conclusions: dMRI can distinguish normal from malignant bone marrow. It may identify malignant bone marrow infiltration in patients with negative static MRI and serve as both a diagnostic and prognostic tool for patients with bone marrow malignancies

Relative output factor measurements of a 5 mm diameter radiosurgical photon beam using polymer gel dosimetry

Besides the fine spatial resolution inherent in polymer gel-magnetic resonance imaging (MRI) dosimetry, the method also features the potential for multiple measurements of varying sensitive volume in a single experiment by integrating results in MRI voxels of finite dimensions (i.e., in plane resolution by slice thickness). This work exploits this feature of polymer gel dosimetry to propose an experimental technique for relative output factor (OF) measurements of small radiosurgical beams. Two gel vials were irradiated with a 5 and 30 mm diameter 6 MV radiosurgery beam and MR scanned with the same slice thickness and three different in plane resolutions. Using this experimental data set, 5 mm OF measurements with the PinPoint ion chamber are simulated by integrating results over a sensitive volume equal to that of the chamber. Results are found in agreement within experimental uncertainties with actual PinPoint measurements verifying the validity of the proposed experimental procedure. The polymer gel data set is subsequently utilized for OF measurements of the 5 mm beam with varying sensitive volume to discuss the magnitude of detector volume averaging effects. Seeking to correct for volume averaging, results are extrapolated to zero sensitive volume yielding a 5 mm OF measurement of (0.66 +/- 5%). This result compares reasonably with corresponding ionometric and radiographic film measurements of this work and corresponding, limited, data in the literature. Overall, results suggest that polymer gel dosimetry coupled with the proposed experimental procedure helps overcome not only tissue-equivalence and beam perturbation implications but also volume averaging and positioning uncertainties which constitute the main drawback in small radiosurgical beam dosimetry. (c) 2005 American Association of Physicists in Medicine

Measuring the tail of the dog that doesn't bark in the night: the case of the national evaluation of Choose Life (the national strategy and action plan to prevent suicide in Scotland)

Background Learning about the impact of public health policy presents significant challenges for evaluators. These include the nebulous and organic nature of interventions ensuing from policy directives, the tension between long-term goals and short-term interventions, the appropriateness of establishing control groups, and the problems of providing an economic perspective. An example of contemporary policy that has recently been subject to evaluation is the first phase of the innovative Scottish strategy for suicide prevention (Choose Life). Discussion and summary This paper discusses how challenges, such as those above, were made manifest within this programme. After a brief summary of the overarching approach taken to evaluating the first phase of Choose Life, this paper then offers a set of recommendations for policymakers and evaluators on how learning from a second phase might be augmented. These recommendations are likely to have general resonance across a range of policy evaluations as they move from early planning and implementation to more mature phases