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  1. Abstract: Given that pair programming has proved to be an effective pedagogical approach for teaching programming skills, it is now important to explore alternative collaborative configurations. One popular configuration is where dyads collaborate by sharing a single computer sitting side-by-side. However, prior research points to potential challenges for elementary students when sharing a single computer when collaborating. This prompted us to explore another configuration where dyads sit side by side but collaborate on a shared virtual platform with individual computers. We compared the discourse of students’ collaboration under these two settings. Results show that although there are no significant differences in the amount of collaborative talk between the two configurations, there is qualitative evidence of how differing affordances of two configurations shape collaborative elementary students’ practices. 
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  2. Collaboration plays an essential role in computer science. While there is growing recognition that learners of all ages can benefit from collaborative learning, little is known about how elementary age children engage in collaborative problem solving in computer science. This paper reports on the analysis of a dataset of elementary students collaborating on a programming project. We found that children tend to make several different types of suggestions. In turn, their partners address those suggestions in different ways such as by implementing them directly in code or by replying through dialogue. We observe that students regularly accept or reject suggestions without explanation or explicit acknowledgement and that it is often unclear whether they understand the substance of the suggestion. These behaviors may inhibit the development of a shared understanding between the partners and limit the value of the collaborative process. These results can inform instructional practice and the development of new adaptive tools that facilitate productive collaborative problem solving in computer science. 
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  3. Abstract The Murchison Widefield Array (MWA) is an electronically steered low-frequency (<300 MHz) radio interferometer, with a ‘slew’ time less than 8 s. Low-frequency (∼100 MHz) radio telescopes are ideally suited for rapid response follow-up of transients due to their large field of view, the inverted spectrum of coherent emission, and the fact that the dispersion delay between a 1 GHz and 100 MHz pulse is on the order of 1–10 min for dispersion measures of 100–2000 pc/cm 3 . The MWA has previously been used to provide fast follow-up for transient events including gamma-ray bursts (GRBs), fast radio bursts (FRBs), and gravitational waves, using systems that respond to gamma-ray coordinates network packet-based notifications. We describe a system for automatically triggering MWA observations of such events, based on Virtual Observatory Event standard triggers, which is more flexible, capable, and accurate than previous systems. The system can respond to external multi-messenger triggers, which makes it well-suited to searching for prompt coherent radio emission from GRBs, the study of FRBs and gravitational waves, single pulse studies of pulsars, and rapid follow-up of high-energy superflares from flare stars. The new triggering system has the capability to trigger observations in both the regular correlator mode (limited to ≥0.5 s integrations) and using the Voltage Capture System (VCS, 0.1 ms integration) of the MWA and represents a new mode of operation for the MWA. The upgraded standard correlator triggering capability has been in use since MWA observing semester 2018B (July–Dec 2018), and the VCS and buffered mode triggers will become available for observing in a future semester. 
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  4. Abstract The Murchison Widefield Array (MWA) is an open access telescope dedicated to studying the low-frequency (80–300 MHz) southern sky. Since beginning operations in mid-2013, the MWA has opened a new observational window in the southern hemisphere enabling many science areas. The driving science objectives of the original design were to observe 21 cm radiation from the Epoch of Reionisation (EoR), explore the radio time domain, perform Galactic and extragalactic surveys, and monitor solar, heliospheric, and ionospheric phenomena. All together $60+$ programs recorded 20 000 h producing 146 papers to date. In 2016, the telescope underwent a major upgrade resulting in alternating compact and extended configurations. Other upgrades, including digital back-ends and a rapid-response triggering system, have been developed since the original array was commissioned. In this paper, we review the major results from the prior operation of the MWA and then discuss the new science paths enabled by the improved capabilities. We group these science opportunities by the four original science themes but also include ideas for directions outside these categories. 
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