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We observed five clusters of upper‐level compact intracloud discharges (CIDs) moving positive charge up over land and over water in Florida. The clusters each contained 3 to 6 CIDs, and the overall cluster duration ranged from 27 to 58 s. On average, the CIDs in a given cluster occurred 11 s apart and were separated by a 3D distance of about 1.5 km. All the clustered CIDs were located above the tropopause and were likely associated with convective surges that penetrated the stratosphere. The average periodicity of CID occurrence within a cluster (every 11 s) was comparable to the periodicity at which the average cluster area is expected to be bombarded by ≥10¹⁶ eV cosmic‐ray particles (every 5 s). Each of such energetic particles gives rise to a cosmic ray shower (CRS) and, in the presence of sufficiently strong electric field over a sufficiently large distance, to a relativistic runaway electron avalanche (RREA). We infer that each of our upper‐level CIDs is likely to be caused by a CRS‐RREA traversing, at nearly the speed of light, the electrified overshooting convective surge and triggering, within a few microseconds, a multitude of streamer flashes along its path, over a distance of the order of hundreds of meters (as per the mechanism recently proposed for lightning initiation by Kostinskiy et al., 2020,https://doi.org/10.1029/2020JD033191). The upper‐level CID clustering was likely made possible by the recurring action of energetic cosmic rays and the rapid recovery of the negative screening charge layer at stratospheric altitudes.

 

One way to personalize chatbot interactions is by establishing common ground with the intended reader. A domain where establishing mutual understanding could be particularly impactful is vaccine concerns and misinformation. Vaccine interventions are forms of messaging which aim to answer concerns expressed about vaccination. Tailoring responses in this domain is difficult, since opinions often have seemingly little ideological overlap. We define the task of tailoring vaccine interventions to a Common-Ground Opinion (CGO). Tailoring responses to a CGO involves meaningfully improving the answer by relating it to an opinion or belief the reader holds. In this paper we introduce Tailor-CGO, a dataset for evaluating how well responses are tailored to provided CGOs. We benchmark several major LLMs on this task; finding GPT-4-Turbo performs significantly better than others. We also build automatic evaluation metrics, including an efficient and accurate BERT model that outperforms finetuned LLMs, investigate how to successfully tailor vaccine messaging to CGOs, and provide actionable recommendations from this investigation. 

The Fearless Steps Apollo (FS-APOLLO) resource is a collection of over 150,000 hours of audio, associated meta-data, and supplemental technological toolkit intended to benefit the (i) speech processing technology, (ii) communication science, team-based psychology, and history, and (iii) education/STEM, preservation/archival communities. The FSAPOLLO initiative which started in 2014 has since resulted in the preservation of over 75,000 hours of NASA Apollo Missions audio. Systems created for this audio collection have led to the emergence of several new Speech and Language Technologies (SLT). This paper seeks to provide an overview of the latest advancements in the FS-Apollo effort and explore upcoming strategies in big-data deployment, outreach, and novel avenues of K-12 and STEM education facilitated through this resource. 

We report on a nano-infrared (IR) imaging and spectroscopy study of epitaxial graphene on silicon carbide (SiC) by using scattering-type scanning near-field optical microscopy (s-SNOM). With nano-IR imaging, we reveal in real space microscopic domains with distinct IR contrasts. By analyzing the nano-IR, atomic force microscopy, and scanning tunneling microscopy imaging data, we conclude that the imaged domains correspond to single-layer graphene, bilayer graphene (BLG), and higher-doped BLG. With nano-IR spectroscopy, we find that graphene can screen the SiC phonon resonance, and the screening is stronger at more conductive sample regions. Our work offers insights into the rich surface properties of epitaxial graphene and demonstrates s-SNOM as an efficient and effective tool in characterizing graphene and possibly other two-dimensional materials.

 

The low-electron flux variability (increase/decrease) in the Earth’s radiation belts could cause low-energy Electron Precipitation (EP) to the atmosphere over auroral and South American Magnetic Anomaly (SAMA) regions. This EP into the atmosphere can cause an extra upper atmosphere’s ionization, forming the auroral-type sporadic E layers (Esa) over these regions. The dynamic mechanisms responsible for developing this Esa layer over the auroral region have been established in the literature since the 1960s. In contrast, there are several open questions over the SAMA region, principally due to the absence (or contamination) of the inner radiation belt and EP parameter measurements over this region. Generally, the Esa layer is detected under the influence of geomagnetic storms during the recovery phase, associated with solar wind structures, in which the time duration over the auroral region is considerably greater than the time duration over the SAMA region. The inner radiation belt’s dynamic is investigated during a High-speed Solar wind Stream (September 24-25, 2017), and the hiss wave-particle interactions are the main dynamic mechanism able to trigger the Esa layer’s generation outside the auroral oval. This result is compared with the dynamic mechanisms that can cause particle precipitation in the auroral region, showing that each region presents different physical mechanisms. Additionally, the difference between the time duration of the hiss wave activities and the Esa layers is discussed, highlighting other ingredients mandatory to generate the Esa layer in the SAMA region.

 

INTRODUCTION: CRSS-UTDallas initiated and oversaw the efforts to recover APOLLO mission communications by re-engineering the NASA SoundScriber playback system, and digitizing 30-channel analog audio tapes – with the entire Apollo-11, Apollo-13, and Gemini-8 missions during 2011-17 [1,6]. This vast data resource was made publicly available along with supplemental speech & language technologies meta-data based on CRSS pipeline diarization transcripts and conversational speaker time-stamps for Apollo team at NASA Mission Control Center, [2,4]. In 2021, renewed efforts over the past year have resulted in the digitization of an additional +50,000hrs of audio from Apollo 7,8,9,10,12 missions, and remaining A-13 tapes. Cumulative digitization efforts have enabled the development of the largest publicly available speech data resource with unprompted, real conversations recorded in naturalistic environments. Deployment of this massive corpus has inspired multiple collaborative initiatives such as Web resources ExploreApollo (https://app.exploreapollo.org) LanguageARC (https://languagearc.com/projects/21) [3]. ExploreApollo.org serves as the visualization and play-back tool, and LanguageARC the crowd source subject content tagging resource developed by UG/Grad. Students, intended as an educational resource for k-12 students, and STEM/Apollo enthusiasts. Significant algorithmic advancements have included advanced deep learning models that are now able to improve automatic transcript generation quality, and even extract high level knowledge such as ID labels of topics being spoken across different mission stages. Efficient transcript generation and topic extraction tools for this naturalistic audio have wide applications including content archival and retrieval, speaker indexing, education, group dynamics and team cohesion analysis. Some of these applications have been deployed in our online portals to provide a more immersive experience for students and researchers. Continued worldwide outreach in the form of the Fearless Steps Challenges has proven successful with the most recent Phase-4 of the Challenge series. This challenge has motivated research in low level tasks such as speaker diarization and high level tasks like topic identification. IMPACT: Distribution and visualization of the Apollo audio corpus through the above mentioned online portals and Fearless Steps Challenges have produced significant impact as a STEM education resource for K-12 students as well as a SLT development resource with real-world applications for research organizations globally. The speech technologies developed by CRSS-UTDallas using the Fearless Steps Apollo corpus have improved previous benchmarks on multiple tasks [1, 5]. The continued initiative will extend the current digitization efforts to include over 150,000 hours of audio recorded during all Apollo missions. ILLUSTRATION: We will demonstrate WebExploreApollo and LanguageARC online portals with newly digitized audio playback in addition to improved SLT baseline systems, the results from ASR and Topic Identification systems which will include research performed on the corpus conversational. Performance analysis visualizations will also be illustrated. We will also display results from the past challenges and their state-of-the-art system improvements. 

Our basic knowledge of downward positive lightning leaders is incomplete due to their rarity and limited ability of VHF mapping systems to image positive streamers. Here, using high‐speed optical records and wideband electric field and magnetic field derivative signatures, we examine in detail the development of a descending positive leader, which extended intermittently via alternating branching at altitudes of 4.2 to 1.9 km and involved luminosity transients separated by millisecond‐scale quiet intervals. We show that the transients (a) are mostly initiated in previously created but already decayed branches, at a distance of the order of 100 m above the branch lower extremity, (b) extend bidirectionally with negative charge moving up, (c) establish a temporary (1 ms or so) steady‐current connection to the negative part of the overall bidirectional leader tree, and (d) exhibit brightening accompanied by new breakdowns at the positive leader end. One of the transients unexpectedly resulted in a negative cloud‐to‐ground discharge. Both positive and negative ends of the transients extended at speeds of 10⁶–10⁷ m/s, while the overall positive leader extension speed was as low as 10³–10⁴ m/s. Wideband electric field signatures of the transients were similar to K‐changes, with their millisecond‐ and microsecond‐scale features being associated with the steady current and new breakdowns, respectively. For transients with both ends visible in our optical records, charge transfers and average currents were estimated to be typically a few hundreds of millicoulombs and some hundreds of amperes, respectively.