Relevance of Ground-based Electron-Induced Electrostatic Discharge Measurements to Space Plasma Environments

Electron-induced electrostatic discharge (ESD) can lead to severe spacecraft anomalies. It is crucial to the success of space missions that the likelihood of ESD occurrence is understood and mitigated. To aid in predicting ESD occurrence, a model for electric fields above and below the charge layer inside an electronirradiated dielectric material was developed. An instrumentation system was also designed to induce and detect ESD events. Because ESD events with a wide range of maximum current values can occur over a range of time intervals, multiple simultaneous detection methods were employed as charge was accumulated on a sample surface; these included monitoring of sample current and optical emissions from the sample surface. Data from ESD experimentation for James Webb Space Telescope (JWST) materials was used to verify that the instrumentation system was effective in inducing and observing ESD. Two types of discharge events were observed during JWST testing: a sudden-onset, decaying current accompanied by luminescence in the optical data, and an arc or flash in optical data. JWST test results were applied to the electric field models developed to determine the threshold electric field for luminescence onset. The models were also applied to the JWST materials in five different space plasma environments to determine the accumulated electric field as a function of time, and to thereby predict the likelihood of sample luminescence in each location

Molecular and clinical characterization of de novo and familial cases with microduplication 3q29: guidelines for copy number variation case reporting

Microdeletions of 3q29 have previously been reported, but the postulated reciprocal microduplication has only recently been observed. Here, cases from four families, two ascertained in Toronto (Canada) and one each from Edinburgh (UK) and Leiden (Netherlands), carrying microduplications of 3q29 are presented. These families have been characterized by cytogenetic and molecular techniques, and all individuals have been further characterized with genome-wide, high density single nucleotide polymorphism (SNP) arrays run at a single centre (The Centre for Applied Genomics, Toronto). In addition to polymorphic copy-number variants (CNV), all carry duplications of 3q29 ranging in size from 1.9 to 2.4 Mb, encompassing multiple genes and defining a minimum region of overlap of about 1.6 Mb bounded by clusters of segmental duplications that is remarkably similar in location to previously reported 3q29 microdeletions. Consistent with other reports, the phenotype is variable, although developmental delay and significant ophthalmological findings were recurrent, suggesting that dosage sensitivity of genes located within 3q29 is important for eye and CNS development. We also consider CNVs found elsewhere in the genome for their contribution to the phenotype. We conclude by providing preliminary guidelines for management and anticipatory care of families with this microduplication, thereby establishing a standard for CNV reporting