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  1. null (Ed.)
    This symposium will focus on five projects’ professional development efforts to enhance educators’ understanding and use of the Next Generation Science Standards (NGSS). Involving educators from preschool to middle school levels in diverse contexts, each project has worked in this problem space in different ways. Of central importance to all the projects is how the NGSS necessitate productive classroom discourse, but the projects differ on how to support educators to achieve “rich science talk.” For example, an “assessment for learning” lens guides one group’s work, while recognizing language and argument as epistemic tools is the driving conceptual framework for another. In this symposium, project leaders discuss the decisions and dilemmas of, and the lessons learned from, their work. This highly interactive session includes brief introductions from each project followed by time for interaction with the projects’ researchers and materials. Projects will bring materials such as scaffolds for collaborative instructional planning, a formative classroom observation tool to support teachers’ use of productive classroom discourse, and examples of instructional units with 7 curricular features designed to support the vision of the NGSS. The session will culminate with time for crosstalk and discussion. 
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  2. null (Ed.)
  3. Abstract

    The direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils produced in a target material from the WIMP elastic scattering. The experimental identification of the direction of the WIMP-induced nuclear recoils is a crucial asset in this field, as it enables unmistakable modulation signatures for dark matter. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity in argon dual-phase time projection chambers (TPC), that are widely considered for current and future direct dark matter searches. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud. Data were taken with nuclear recoils of known directions and kinetic energy of 72 keV, which is within the range of interest for WIMP-induced signals in argon. The direction-dependent liquid argon charge recombination model by Cataudella et al. was adopted and a likelihood statistical analysis was performed, which gave no indications of significant dependence of the detector response to the recoil direction. The aspect ratioRof the initial ionization cloud is$$R < 1.072$$R<1.072with 90 % confidence level.

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  4. Free, publicly-accessible full text available October 1, 2024
  5. Abstract The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: $${}^{36}\hbox {Ar}$$ 36 Ar , $${}^{38}\textrm{Ar}$$ 38 Ar , and $${}^{40}\textrm{Ar}$$ 40 Ar . We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019. 
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    Free, publicly-accessible full text available May 1, 2024
  6. Free, publicly-accessible full text available June 1, 2024