Visualization of the operational space of edge-localized modes through low-dimensional embedding of probability distributions.

Information visualization aimed at facilitating human perception is an important tool for the interpretation of experiments on the basis of complex multidimensional data characterizing the operational space of fusion devices. This work describes a method for visualizing the operational space on a two-dimensional map and applies it to the discrimination of type I and type III edge-localized modes (ELMs) from a series of carbon-wall ELMy discharges at JET. The approach accounts for stochastic uncertainties that play an important role in fusion data sets, by modeling measurements with probability distributions in a metric space. The method is aimed at contributing to physical understanding of ELMs as well as their control. Furthermore, it is a general method that can be applied to the modeling of various other plasma phenomena as well.

Development of head position preference during early infancy: a longitudinal study in the daily life situation.

We studied developmental changes in supine head position preference in a group of 14 healthy full-term infants from age 3 to 18 weeks. The infants assumed an initial head-right position until 12 weeks. For the maintenance of a head position, a loglinear analysis revealed a developmental trend from an initial head orientation to the right to one with the head in the midline at around 12 weeks. The maintenance of a midline head position was preceded by a marked improvement in postural stabilization, defined as the ability to hold the head upright when seated in an infant chair. The relationship between head position preference and behavioral state changed with age: At 3 weeks all infants maintained the same position regardless of state, but by 18 weeks this situation held for only 64% of those who cried. The implications of these findings for the development of handedness are discussed.

Comparative diagnostic performance of three radiological procedures for the detection of lumbar disk herniation.

Literature data on the diagnostic performance of phlebography, myelography, and CT scan applied to patients with suspected lumbar disk herniation (LDH) are analyzed to extract maximal information about their relative discriminatory power. Seventeen papers meeting the selection criteria contain 13 reports on myelography, 6 on phlebography, and 5 on CT. Sensitivity and specificity are considered simultaneously in logistic ROC space. The reports of each procedure are effectively summarized by a linear regression in logistic ROC space. Taking into account the individual confidence regions of sensitivity and specificity obtained from each report, the slope of the regression line is estimated by Generalized Least Squares (ML). This approach also allows to test the assumption of a common odds ratio (i.e., of a unit slope). The simply to determine common odds ratio as well as the perpendicular distance between the origin and the regression line (as a good approximation to the area under the ROC curve) are used as a measure for the discriminatory power of the procedures. For CT, homogeneity of sensitivity turns out to be much more likely than a common odds ratio. Based on the available, retrospective data, phlebography appears to have the highest performance in visualizing an LDH, followed by myelography and CT.

Quieting during early infancy: evidence for a developmental change?

The ability to terminate crying (quieting) without intervention was studied from 0 to 18 weeks. Two groups were involved: 11 newborns during the first hour after birth and a longitudinal group of 14 infants seen every 3 weeks from 3 to 18 weeks. Most newborns who cried showed quieting with and without hand-mouth contacting. In the longitudinal group quieting with hand-mouth contacting appeared for the first time at 9 weeks (quieting without hand-mouth contacting being present from 3 weeks). Quieting with hand-mouth contacting was frequently accompanied by hand chewing/sucking. Explanations for the disappearance in quieting with hand-mouth contacting and its reappearance at 9 weeks concern changes in movement and posture. Explanations based on notions of intentionality in quieting were not supported by the data.

Toward individual prognosis of IgA nephropathy.

The individual prognosis of adult IgA nephropathy patients was studied using the proportional hazards model for the time from biopsy until endstage renal disease. After selection of the most relevant prognostic factors, the 75 patients were stratified with respect to hypertension and its treatment. In these strata, individual prognosis was based on the initial age-adjusted glomerular filtration rate, the initial proteinuria, the presence/absence of gross hematuria, and the presence/absence of microscopic hematuria. Using the scores of a patient on these variables, the probability of surviving any given period of time can be estimated either graphically or by calculation. Prediction is feasible up to about 10 years. Attention has been given to supply all relevant estimates with confidence limits. For each patient the estimated 5-year survival probability as predicted by the model was compared with the actual outcome.