There has been an exciting recent development in auroral research associated with the discovery of a new subauroral phenomenon called STEVE (Strong Thermal Emission Velocity Enhancement). Although STEVE has been documented by amateur night sky watchers for decades, it is as yet an unidentified upper atmosphere phenomenon. Observed first by amateur auroral photographers, STEVE appears as a narrow luminous structure across the night sky over thousands of kilometers in the east-west direction. In this paper, we present the first statistical analysis of the properties of 28 STEVE events identified using Time History of Events and Macroscale Interactions during Substorms (THEMIS) all-sky imager and the Redline Emission Geospace Observatory (REGO) database. We find that STEVE occurs about 1 hr after substorm onset at the end of a prolonged expansion phase. On average, the AL index magnitude is larger and the expansion phase has a longer duration for STEVE events compared to subauroral ion drifts or substorms. The average duration for STEVE is about 1 hr, and its latitudinal width is~20 km, which corresponds to~¼ of the width of narrow auroral structures like streamers. STEVE typically has an equatorward displacement from its initial location of about 50 km and a longitudinal extent of 2,145 km. Plain Language Summary Strong Thermal Emission Velocity Enhancement (STEVE) is anatmospheric phenomenon that manifests across the night sky as an extremely thin yet long ribbon of vibrant purple and white hues. Although STEVE has been well documented by amateur auroral photographers for several decades, the scientific community only recently stumbled upon this phenomenon. In this paper, we report on the first statistical analysis of STEVE's optical characteristics using ground-based all-sky imagery and examined satellite data to determine the geomagnetic conditions favorable for the formation of STEVE. Our results verify that STEVE is narrow in the north-south direction, but it extends over a wider east-west region. We have also determined that STEVE displaces southward over its lifetime in most observations. More interestingly, all 28 STEVE events identified in this study were observed at the end of a prolonged substorm expansion phase. More recently, Gallardo-Lacourt et al. (2018) analyzed data from the Polar-Orbiting Environmental Satellite (POES)-17 satellite for one STEVE event identified by Time History of Events and Macroscale Interactions GALLARDO-LACOURT ET AL. 9893

Two commonly used methodologies for species detection within processed meat products are real-time polymerase chain reaction (PCR), a DNA-based method, and enzyme-linked immunosorbent assay (ELISA), a protein-based method. In this study, a real-time PCR assay was compared to a commercial ELISA kit based on sensitivity, specificity, agreement among duplicate samples, cost, time, and ease of use. Fifteen reference samples containing known percentages (0.1-99.9%, w/w) of pork and beef were analyzed in duplicate using both methods. Thirty commercial products, including sausages, pet treats, and canned meats, were also tested in duplicate with each method. Reference sample analysis showed real-time PCR was able to detect pork in duplicate samples at 0.10% and beef at 0.50% in the binary mixtures. ELISA detected pork in duplicate samples at 10.0% and beef at 1.00% in the binary mixtures. When the results of reference and commercial samples were combined, real-time PCR demonstrated the greatest agreement among duplicate samples, at 96.7%, compared to 95.6% agreement for ELISA. The real-time PCR assay used in this study was found to be less expensive, while ELISA was less time-consuming and easier to perform. Both methods were successful at identifying species in ground meats, sausage, and deli meat samples; however, pet treats and canned meats proved more challenging. Overall, it was determined that the real-time PCR assay was optimal for species identification in processed meat products when a low detection limit is required; however, the ELISA kit may be advantageous in other situations due to its ease of use.

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Sporadic-E (Es) occurrence rates from Global Position Satellite radio occultation (GPS-RO) measurements have shown to vary by a factor of five between studies, motivating the need for a comparison with ground-based measurements. In an attempt to find accurate GPS-RO techniques for detecting Es formation, occurrence rates derived using five previously developed GPS-RO techniques are compared to ionosonde measurements over an eight-year period from 2010–2017. GPS-RO measurements within 170 km of a ionosonde site are used to calculate Es occurrence rates and compared to the ground-truth ionosonde measurements. The techniques are compared individually for each ionosonde site and then combined to determine the most accurate GPS-RO technique for two thresholds on sporadic-E intensity: no lower limit and fbEs ≥3 MHz. Overall, the YuS4 method shows the closest agreement with ionosonde measurements for total Es occurrence rates without a lower limit on intensity, while the phase-based Chu technique shows the closest agreement for fbEs ≥3 MHz. This analysis demonstrates that the variation in GPS-RO derived sporadic-E occurrence rates is due to varying thresholds on the sporadic-E intensities in terms of fbEs.