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This manuscript reports on the direct observation of a $\beta$-delayed two-neutron emission in a study of ${}^{134}\mathrm{In}$at the ISOLDE Decay Station using neutron spectroscopy. We also report on the first measurement in ${\beta }^{-}$decay of the long-sought $13/2^{+}$excited state in ${}^{133}\mathrm{Sn}$, attributed to be the neutron single-particle $i_{13/2}$orbital. The observation of sequential neutron emission is used to extract the relative population of the $i_{13/2}$state, which was found to be much smaller than the predictions of the statistical model. The experiment was possible because of the innovative use of a neutron array with neutron discrimination and interaction tracking capabilities. This is the first study of the details of the two-neutron emission for a nucleus, which belongs to the $r$-process path. Understanding $\beta$-delayed two-neutron emission probabilities is essential to validate models used in astrophysical $r$-process nucleosynthesis calculations. Observing two-neutron emissions in ${\beta }^{-}$decay paves the way for new experiments to study energy and angular correlations for $\beta$-delayed multineutron emitters. 

The polar and high latitude regions of the ionosphere are host to complex plasma processes involving Magnetosphere-Ionosphere (MI) coupling, plasma convection, and auroral dynamics. The magnetic field lines from the polar cusp down through the auroral region map out to the magnetosphere and project the footprint of the large-scale convective processes driven by the solar wind onto the ionosphere. This region is also a unique environment where the magnetic field is oriented nearly vertical, resulting in horizontal drifts along closed, localized, convection patterns, and where prolonged periods of darkness during the winter result in the absence of significant photoionization. This set of conditions results in unique ionospheric structures which can set the stage for the generation of the gradient drift instability (GDI). The GDI occurs when the density gradient and ExB plasma drift are in the same direction. The GDI is a source of structuring at density gradients and may give rise to ionospheric irregularities that impact over-the-horizon radars and GPS signals. While the plasma ExB drifts are supplied by magnetospheric convection and MI coupling, sharp density gradients in the polar regions will be present at polar holes. Since the GDI occurs where the density gradient and plasma drift are parallel, the ionospheric irregularities caused by the GDI should occur at the leading edge of the polar hole. If so, the resulting production of small-scale density irregularities may, if the density is high enough, give rise to scintillation of GNSS signals and backscatter on HF radars. In this study, we investigate whether these irregularities can occur at the edges of polar holes as detected by the HF radar scatter. We use the Ionospheric Data Assimilation 4-Dimentional (IDA4D) and Assimilative Mapping of Ionospheric Electrodynamics (AMIE) models to characterize the high latitude ionospheric density and ExB drift convective structures, respectively, for one of nine polar hole events identified using RISR-N incoherent scatter radar in Forsythe et al [2021]. The combined IDA4D and AMIE assimilative outputs indicate where the GDI could be triggered, e.g., locations where the density gradient and ExB drift velocity have parallel components and the growth rate is smaller than the characteristic time over which the convective pattern changes, in this case, ~1/15 min. The presence of decameter ionospheric plasma irregularities is detected using the Super Dual Auroral Radar Network (SuperDARN). SuperDARN radars are HF coherent scatter radars. The presence of ionospheric radar returns in regions unstable to GDI grown strongly suggest the GDI is producing decameter scale plasma irregularities. The statistical analyses conducted in the above investigation do not show a clear pattern of enhanced scatter with larger computed GDI growth rates. Further investigation must be conducted before concluding that the GDI does not cause irregularities detectable with HF radar at polar holes. 

This descriptive study attended to the extent to which we see evidence of the presence of four practices that promote equity and access in 141 grades 3-8 mathematics lessons in the United States. We found that lessons generally showed evidence of some incorporation of the practices but often not at the highest level. Teachers in this sample engaged in social coaching at a relatively high level, across elementary and middle school classrooms. Teachers tended to do less with respect to supporting connection and engagement between student context and the math learning environment. We also found statistically significant differences between elementary and middle school lessons in positioning students as competent and supporting a nurturing environment by proactively building relationships and productive classroom culture. We offer possible interpretations and a few brief implications of these findings. 

This study examines the utilization of cognitive interviews longitudinally over a one-year period to collectively trace raters’ response processes as they interpreted and scored with observational rubrics designed to measure teaching practices that promote equity and access in elementary and middle school mathematics classrooms. We draw on four rounds of cognitive interviews (totaling 14 interviews) that involved four raters at purposeful time points spread over the year. Findings reported in this study focus on raters’ responses about one rubric, positioning students as competent. The findings point to the complexities of utilizing observational rubrics and the need to track response processes longitudinally at multiple time points during data collection in order to attend to rater calibration and the reliability and validity of resulting rubric scores. 

Puffer and porcupine fishes (families Diodontidae and Tetraodontidae, order Tetradontiformes) are known for their extraordinary ability to triple their body size by swallowing and retaining large amounts of seawater in their accommodating stomachs. This inflation mechanism provides a defence to predation; however, it is associated with the secondary loss of the stomach's digestive function. Ingestion of alkaline seawater during inflation would make acidification inefficient (a potential driver for the loss of gastric digestion), paralleled by the loss of acid–peptic genes. We tested the hypothesis of stomach inflation as a driver for the convergent evolution of stomach loss by investigating the gastric phenotype and genotype of four distantly related stomach inflating gnathostomes: sargassum fish, swellshark, bearded goby and the pygmy leatherjacket. Strikingly, unlike in the puffer/porcupine fishes, we found no evidence for the loss of stomach function in sargassum fish, swellshark and bearded goby. Only the pygmy leatherjacket (Monochanthidae, Tetraodontiformes) lacked the gastric phenotype and genotype. In conclusion, ingestion of seawater for inflation, associated with loss of gastric acid secretion, is restricted to the Tetraodontiformes and is not a selective pressure for gastric loss in other reported gastric inflating fishes.