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  1. Academic Editor: García-Aracil, Adela (Ed.)
    This is the first of two sequential papers describing the design and first-year implementation of a collaborative participatory action research effort between Sociedad Latina, a youth serving organization in Boston, Massachusetts, and Boston University. The collaboration aimed to develop and deliver a combined STEM and career development set of lessons for middle school Latinx youth. In the first paper, life design and the U.N. Sustainable Development Goals are described in relation to the rationale and the design of the career development intervention strategy that aims to help middle school youth discover the ways that learning advanced-STEM skills expand future decentmore »work opportunities both within STEM and outside STEM, ultimately leading to an outcome of well-being and sustainable communities. In addition to providing evidence of career development intervention strategies, a qualitative analysis of the collaboration is described. The second paper will discuss two additional frameworks that guided the design and implementation of our work. As an example of translational research, the paper will provide larger national and regional contexts by describing system level career development interventions underway using Bronfenbrenner’s bioecological and person–process–context–time frameworks.« less
    Free, publicly-accessible full text available November 29, 2022
  2. Abstract

    The superior density of passive analog-grade memristive crossbar circuits enables storing large neural network models directly on specialized neuromorphic chips to avoid costly off-chip communication. To ensure efficient use of such circuits in neuromorphic systems, memristor variations must be substantially lower than those of active memory devices. Here we report a 64 × 64 passive crossbar circuit with ~99% functional nonvolatile metal-oxide memristors. The fabrication technology is based on a foundry-compatible process with etch-down patterning and a low-temperature budget. The achieved <26% coefficient of variance in memristor switching voltages is sufficient for programming a 4K-pixel gray-scale pattern with a <4% relativemore »tuning error on average. Analog properties are also successfully verified via experimental demonstration of a 64 × 10 vector-by-matrix multiplication with an average 1% relative conductance import accuracy to model the MNIST image classification by ex-situ trained single-layer perceptron, and modeling of a large-scale multilayer perceptron classifier based on more advanced conductance tuning algorithm.

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  3. Abstract

    We report the identification of metastable isomeric states of$$^{228}$$228Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the$$\beta $$β-decay of$$^{228}$$228Ra, a component of the$$^{232}$$232Th decay chain, with$$\beta $$βQ-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of$$^{228}$$228Ra as well as the relative abundance of$$^{232}$$232Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.

  4. Free, publicly-accessible full text available August 1, 2022
  5. Free, publicly-accessible full text available July 1, 2022
  6. This work establishes a means to exploit genetic networks to create living synthetic composites that change shape in response to specific biochemical or physical stimuli. Baker’s yeast embedded in a hydrogel forms a responsive material where cellular proliferation leads to a controllable increase in the composite volume of up to 400%. Genetic manipulation of the yeast enables composites where volume change on exposure to l -histidine is 14× higher than volume change when exposed to d -histidine or other amino acids. By encoding an optogenetic switch into the yeast, spatiotemporally controlled shape change is induced with pulses of dim bluemore »light (2.7 mW/cm 2 ). These living, shape-changing materials may enable sensors or medical devices that respond to highly specific cues found within a biological milieu.« less