Dataset Information

Meter-scale spark X-ray spectrum statistics.

ABSTRACT: X-ray emission by sparks implies bremsstrahlung from a population of energetic electrons, but the details of this process remain a mystery. We present detailed statistical analysis of X-ray spectra detected by multiple detectors during sparks produced by 1 MV negative high-voltage pulses with 1 μs risetime. With over 900 shots, we statistically analyze the signals, assuming that the distribution of spark X-ray fluence behaves as a power law and that the energy spectrum of X-rays detectable after traversing ∼2 m of air and a thin aluminum shield is exponential. We then determine the parameters of those distributions by fitting cumulative distribution functions to the observations. The fit results match the observations very well if the mean of the exponential X-ray energy distribution is 86 ± 7 keV and the spark X-ray fluence power law distribution has index -1.29 ± 0.04 and spans at least 3 orders of magnitude in fluence.

SUBMITTER: Carlson BE

PROVIDER: S-EPMC5102163 | biostudies-other | 2015 Nov

REPOSITORIES: biostudies-other

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Meter-scale spark X-ray spectrum statistics.

Carlson B E BE Østgaard N N Kochkin P P Grondahl Ø Ø Nisi R R Weber K K Scherrer Z Z LeCaptain K K

Journal of geophysical research. Atmospheres : JGR 20151113 21

X-ray emission by sparks implies bremsstrahlung from a population of energetic electrons, but the details of this process remain a mystery. We present detailed statistical analysis of X-ray spectra detected by multiple detectors during sparks produced by 1 MV negative high-voltage pulses with 1 μs risetime. With over 900 shots, we statistically analyze the signals, assuming that the distribution of spark X-ray fluence behaves as a power law and that the energy spectrum of X-rays detectable after ...[more]

PMID: 27867779

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Project description:BackgroundMotor impairments are pervasive in Autism Spectrum Disorder (ASD); however, children with ASD rarely receive a dual diagnosis of Developmental Coordination Disorder (DCD). The Simons Foundation SPARK study engaged families affected by ASD through an online study.ObjectivesThe DCD parent questionnaire (DCDQ) was used to assess the prevalence of a risk for motor impairment or DCD in children with ASD between 5 and 15 years of age.DesignThis study utilizes parent reports from a large database of children with ASD.MethodsA total of 16,705 parents of children with ASD completed the DCDQ. We obtained our final SPARK dataset (n = 11,814) after filtering out invalid data, using stronger cut-offs to confirm ASD traits, and excluding children with general neuromotor impairments/intellectual delays. We compared DCDQ total and subscale scores from the SPARK dataset with published norms for each age between 5 and 15 years.ResultsThe proportion of children with ASD at risk for a motor impairment was very high at 86.9%. Children with ASD did not outgrow their motor impairments and continued to present with a risk for DCD even into adolescence. Yet, only 31.6% of children were receiving physical therapy services.LimitationsOur analysis of a large database of parent-reported outcomes using the DCDQ did not involve follow-up clinical assessments.ConclusionsUsing a large sample of children with ASD, this study shows that a risk for motor impairment or DCD was present in most children with ASD and persists into adolescence; however, only a small proportion of children with ASD were receiving physical therapist interventions. A diagnosis of ASD must trigger motor screening, evaluations, and appropriate interventions by physical and occupational therapists to address the functional impairments of children with ASD while also positively impacting their social communication, cognition, and behavior. Using valid motor measures, future research must determine if motor impairment is a fundamental feature of ASD.

Dataset Information

Meter-scale spark X-ray spectrum statistics.

Publications

Meter-scale spark X-ray spectrum statistics.

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