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We have developed, built, and tested a new feed design for interferometric radio telescopes with "large-$N$, small-$D$" designs. Those arrays require low-cost and low-complexity feeds for mass production on reasonable timescales and budgets, and also require those feeds to be compact to minimize obstruction of the dishes, along with having ultra wide bands of operation for most current and future science goals. The feed presented in this paper modifies the exponentially tapered slot antenna (Vivaldi) and quad-ridged flared horn antenna designs by having an oversized backshort, a novel method of maintaining a small size that is well-suited for deeper dishes ($f/D\leq 0.25$). It is made of laser cut aluminum and printed circuit boards, such that it is inexpensive ($\lesssim$ 75 USD per feed in large-scale production) and quick to build; it has a 5:1 frequency ratio, and its size is approximately a third of its longest operating wavelength. We present the science and engineering constraints that went into design decisions, the development and optimization process, and the simulated performance. A version of this feed design was optimized and built for the Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) prototypes. When simulated on CHORD's very deep dishes ($f/D=0.21$) and with CHORD's custom first stage amplifiers, the on-sky system temperature $T_\mathrm{sys}$ of the complete receiving system from dish to digitizer remains below 30 K over most of the 0.3-1.5 GHz band, and maintains an aperture efficiency $\eta_\mathrm{A}$ between 0.4 and 0.6. The entire receiving chain operates at ambient temperature. The feed is designed to slightly under-illuminate the CHORD dishes, in order to minimize coupling between array elements and spillover., Comment: 19 pages, 13 figures

In 2016, McREL and the University of Southern California (USC) were awarded a grant from the U.S. Department of Education's Investing in Innovation (i3) Fund (Award Number U411C150011) to develop a translation of the identity-based motivation (IBM) in vivo program "Pathways to Success" to a digital platform to deliver IBM to middle and high school students. The resulting digital "Pathways to Success" program consisted of 12 15-minute digital platform activities, planned to take place over the first six to eight weeks in the Fall semester of 2017 in 10 schools from five districts in Colorado. While the former McREL research director and the original external evaluator led the field operation and the randomization process, in 2018, there was a change in the Principal Investigator at McREL, and an evaluator from USC was contacted to conduct the independent evaluation. Project data, including student and teacher responses and administrative data from schools in years 2016-2017, 2017-2018, and 2018-2019 were provided by McREL to the USC evaluator. The report documented the implementation fidelity and examined the impact of digital "Pathways to Success" on students' overall, English language, and Math achievement, and "non-cognitive" variables in the IBM theory.