High density plasma gun generates plasmas at 190 kilometers per second

Gun has thin metal foil disc which positions or localizes gas to be ionized during electrical discharge cycle, overcoming major limiting factor in obtaining such plasmas. Expanding plasma front travels at 190 km/sec, compared to plasmas of 50 to 60 km/sec previously achieved

Seasonal variation in the correlation of airglow temperature and emission rate

The hydroxyl (OH) rotational temperature and band emission rate have been derived using year-round, ground-based measurements of the infrared OH nightglow from Sweden from 1991 to 2002. Recent work has suggested that, during the winter, all scales of dynamical variations of radiance and temperature arise from vertical motions, implying that the effective source concentrations of atomic oxygen are constant. The present data show correlations between temperature and radiance both during winter and summer that are consistent with those observed in that previous work. However, during the transition to summer there is a rapid decrease in the temperature and its variation that is not reflected in the band radiance, suggesting that only the shorter-scale variations are accompanied by significant vertical motion. This indicates that the shorter-scale dynamical variations occur against an independent, seasonally changing background temperature profile in a way that is consistent with that predicted by gravity-wave models

Airglow Derived Measurements of Q-Branch Transition Probabilities for Several Hydroxyl Meinel Bands

Spectroscopic measurements of the hydroxyl (OH) airglow emissions are often used to infer neutral temperatures near the mesopause. Correct Einstein coefficients for the various transitions in the OH airglow are needed to calculate accurate temperatures. However, studies showed experimentally and theoretically that the most commonly used Einstein spontaneous emission transition probabilities for the Q-branch of the OH Meinel (6,2) transition are overestimated. Extending their work to several Delta v = 2 and 3 transitions from v' = 3 to 9, we have determined Einstein coefficients for the first four Q-branch rotational lines. These have been derived from high resolution, high signal to noise spectroscopic observations of the OH airglow in the night sky from the Nordic Optical Telescope. The Q-branch Einstein coefficients calculated from these spectra show that values currently tabulated in the HITRAN database overestimate many of the Q-branch transition probabilities. The implications for atmospheric temperatures derived from OH Q-branch measurements are discussed

Neuropsychologic function in toddlers exposed to cocaine in utero: A preliminary study

Patterns of neuropsychological performance on A-not-B, inhibition, motor, cognitive, language, and behavior tasks were examined in 34 toddlers--17 cocaine-exposed (CE) and 17 nonexposed (NE) controls. CE toddlers exhibited greater perseveration, less inhibition, poorer emotional regulation, and less task orientation relative to NE toddlers. Overall cognitive and language skills and motor impairment status were comparable among CE and NE toddlers. Differences in perseveration, emotional regulation, and task orientation between CE and NE toddlers remained significant after statistically controlling for overall cognitive skill. Prenatal cocaine exposure may impart selective vulnerability for deficits in executive function, inhibition, and emotional regulation in toddlers, perhaps related to the concurrent rapid frontal lobe maturation and the neurobiology of cocaine. Furthermore, these findings suggest that performance can be broken down into meaningful neuropsychological components in very young children

Executive functioning in preschool children: Performance on A-Not-B and other delayed response format tasks

The A-not-B (AB) task has been hypothesized to measure executive/frontal lobe function; however, the developmental and measurement characteristics of this task have not been investigated. The present study examined performance on AB and comparison tasks adapted from developmental and neuroscience literature in 117 1.9-5.5 yr old preschool children. Age significantly predicted performance on AB, Delayed Alternation, Spatial Reversal, Color Reversal, and Self-Control tasks. A 4-factor analytic model best fit task performance data. AB task indices loaded on 2 factors with measures from the Self-Control and Delayed Alternation tasks, respectively. AB indices did not load with those from the reversal tasks despite similarities in task administration and presumed cognitive demand (working memory). These results indicate that AB is sensitive to individual differences in age-related performance in preschool children and suggest that AB performance is related to both working memory and inhibition processes in this age range

The effect of energetic electron precipitation on middle mesospheric night-time ozone during and after a moderate geomagnetic storm

Using a ground-based microwave radiometer at Troll Station, Antarctica (72°S, 2.5°E, L = 4.76), we have observed a decrease of 20–70% in the mesospheric ozone, coincident with increased nitric oxide, between 60 km and 75 km altitude associated with energetic electron precipitation (E > 30 keV) during a moderate geomagnetic storm (minimum Dst of −79 nT) in late July 2009. NOAA satellite data were used to identify the precipitating particles and to characterize their energy, spatial distribution and temporal variation over Antarctica during this isolated storm. Both the ozone decrease and nitric oxide increase initiate with the onset of the storm, and persist for several days after the precipitation ends, descending in the downward flow of the polar vortex. These combined data present a unique case study of the temporal and spatial morphology of chemical changes induced by electron precipitation during moderate geomagnetic storms, indicating that these commonplace events can cause significant effects on the middle mesospheric ozone distribution

ALOHA-93 Measurements of Intrinsic AGW Characteristics Using the Airborne Airglow Imager and Groundbased Na Wind/Temperature Lidar

Monochromatic Acoustic Gravity Waves (AGWs) with periods \u3c 1 hour are a prevalent feature in the mesospheric airglow layers. These waves are important dynamically and energetically to the region where their temporal and spatial morphology are not well established. The purpose of this study is establish the intrinsic AGW characteristics over an extended region (as flown by the NCAR Electra aircraft) and to present the data in terms of the predicted spectral domain defined by the Brunt‐Vaisala frequency and the diffusive filtering limit proposed by Gardner [1994]. On October 21, 1993, observations were made from the NCAR Electra aircraft during a 6 hour flight in a large triangle N and W of Maui, for a integral distance of ∼3000 km. The entire area observed [∼1 M km²] had a monochromatic AGW propagating toward the NW and the western half had a SW propagating wave superimposed. These waves were also observed with the Michelson interferometer on the aircraft and an airglow imager at the Haleakala location during this time. Intrinsic phase velocities were computed where the Na Wind/Temperature (W/T) lidar at Haleakala provided a measure of the mean wind to compensate phase velocities observed with the imager. The data were tabulated and plotted in an AGW spectral reference frame and compared to cutoff conditions predicted by diffusive filtering theory