Positive-strand RNA viruses—a Keystone Symposia report

Positive-strand RNA viruses have been the cause of several recent outbreaks and epidemics, including the Zika virus epidemic in 2015, the SARS outbreak in 2003, and the ongoing SARS-CoV-2 pandemic. On June 18–22, 2022, researchers focusing on positive-strand RNA viruses met for the Keystone Symposium “Positive-Strand RNA Viruses” to share the latest research in molecular and cell biology, virology, immunology, vaccinology, and antiviral drug development. This report presents concise summaries of the scientific discussions at the symposium

The ELFIN mission

The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (Torbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E 1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.Published versio

Globally optimal joint design of two sets of mask coefficients in two different predefined rotated axes of time frequency plane for signal restoration applications

The benefits of applying two mask operations in two different rotated axes of the time frequency (TF) plane are well known especially for signal restoration applications. Compared to just applying a single mask operation in a single rotated axis of the TF plane, it has been shown that applying two mask operations in two different rotated axes of the TF plane carefully can improve the restoration performances. However, there is no systematic approach for the globally optimal joint design of these two sets of mask coefficients in two different predefined rotated axes of the TF plane. In this paper, this optimal joint design problem is formulated as a nonconvex optimization problem. Then, a modified filled function method is employed for finding the globally optimal solution of the optimization problem. Computer numerical simulation results show that the obtained restoration system outperforms existing ones

Repetitive behaviours in typically developing 2-year-olds

Background: Repetitive behaviours are an essential part of the diagnosis of autism but are also commonly seen in typically developing children. The current study investigated the frequency and factor structure of repetitive behaviours in a large community sample of 2-year-olds. Methods: A new measure, the Repetitive Behaviour Questionnaire (RBQ-2) was completed by 679 parents. Results: The RBQ-2 had good psychometric properties. A four-factor model provided the best fit for the data, accounting for 51% of the variance, and suggested 4 sub-scales: unusual sensory interests, repetitive motor movements, rigidity/adherence to routine and preoccupations with restricted patterns of interest. These sub-scales closely resembled repetitive behaviour subtypes within the ICD-10 criteria for autism. Repetitive behaviours of every type were frequently reported. Higher scores were found for all children, and especially boys, on the subscale relating to preoccupations with restricted patterns of interests. Conclusion: The results support the proposal that repetitive behaviours represent a continuum of functioning that extends to the typically developing child population