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This study reported the process of developing and evaluating a student-facing learning analytics dashboard (LAD) for an online STEM skill practice system from a user experience approach. A usability survey was administered to 19 LAD users to gather information on what the learners believed were the most important features and what needed to be done to further improve the design of the LAD. Our findings showed that the most important LAD feature to students was showing the accuracy level of their practice and providing the option to redo the practice. These findings informed the revisions of the preliminary design of the LAD and provided insights into future development of student-facing LADs in online learning environments. 

The amount of light produced by nuclear recoils in scintillating targets is strongly quenched compared to that produced by electrons. A precise understanding of the quenching factor is particularly interesting for weakly interacting massive particles (WIMP) searches and coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) measurements since both rely on nuclear recoils, whereas energy calibrations are more readily accessible from electron recoils. There is a wide variation among the current measurements of the quenching factor in sodium iodide (NaI) crystals, especially below 10 keV, the energy region of interest for dark matter and$\mathrm{CE}\nu \mathrm{NS}$ studies. A better understanding of the quenching factor in NaI(Tl) is of particular interest for resolving the decades-old puzzle in the field of dark matter between the null results of most WIMP searches and the claim for dark matter detection by the DAMA/LIBRA collaboration. In this work, we measured sodium and iodine quenching factors for five small NaI(Tl) crystals grown with similar thallium concentrations and growth procedures. Unlike previous experiments, multiple crystals were tested, with measurements made in the same experimental setup to control systematic effects. The quenching factors agree in all crystals we investigated, and both sodium and iodine quenching factors are smaller than those reported by DAMA/LIBRA. The dominant systematic effect was due to the electron equivalent energy calibration originating from the nonproportional behavior of the NaI(Tl) light yield at lower energies, potentially the cause for the discrepancies among the previous measurements.

Published by the American Physical Society2024 

As 6G wireless communications push the operation frequency above 110 GHz, it is critical to have low-loss interconnects that can be accurately tested. To this end, D-band (110 GHz to 170 GHz) substrate-integrated waveguides (SIWs) are designed on a 100-μm-thick SiC substrate. The fabricated SIWs are probed on-wafer in a single sweep from 70 kHz to 220 GHz with their input/output transitioned to grounded coplanar waveguides (GCPWs). From CPW-probed scattering parameters, two-tier calibration is used to de-embed the SIW-GCPW transitions and to extract the intrinsic SIW characteristics. In general, the record low loss measured agrees with that obtained from finite-element full-wave electromagnetic simulation. For example, across the D band, the average insertion loss is approximately 0.2 dB/mm, which is several times better than that of coplanar or microstrip transmission lines fabricated on the same substrate. A 3-pole filter exhibits a 1-dB insertion loss at 135 GHz with 20-dB selectivity and 11% bandwidth, which is order-of-magnitude better than typical on-chip filters. These results underscore the potential of using SIWs to interconnect transistors, filters, antennas, and other circuit elements on the same monolithically integrated chip. 

We probe the conduction-band offsets (CBOs) and confined states at GaAs/GaAsNBi quantum wells (QWs). Using a combination of capacitance–voltage (C–V) measurements and self-consistent Schrödinger–Poisson simulations based on the effective mass approximation, we identify an N-fraction dependent increase in CBO, consistent with trends predicted by the band anti-crossing model. Using the computed confined electron states in conjunction with photoluminescence spectroscopy data, we show that N mainly influences the conduction band and confined electron states, with a relatively small effect on the valence band and confined hole states in the quaternary QWs. This work provides important insight toward tailoring CBO and confined electron energies, both needed for optimizing infrared optoelectronic devices.

 

We present the largest optical photometry compilation of Gamma-Ray Bursts (GRBs) with redshifts (z). We include 64813 observations of 535 events (including upper limits) from 28 February 1997 to 18 August 2023. We also present a user-friendly web tool grbLC which allows users to visualise photometry, coordinates, redshift, host galaxy extinction, and spectral indices for each event in our database. Furthermore, we have added a Gamma-ray Coordinate Network (GCN) scraper that can be used to collect data by gathering magnitudes from the GCNs. The web tool also includes a package for uniformly investigating colour evolution. We compute the optical spectral indices for 138 GRBs, for which we have at least 4 filters at the same epoch in our sample, and craft a procedure to distinguish between GRBs with and without colour evolution. By providing a uniform format and repository for the optical catalogue, this web-based archive is the first step towards unifying several community efforts to gather the photometric information for all GRBs with known redshifts. This catalogue will enable population studies by providing light curves (LCs) with better coverage since we have gathered data from different ground-based locations. Consequently, these LCs can be used to train future LC reconstructions for an extended inference of the redshift. The data gathering also allows us to fill some of the orbital gaps from Swift in crucial points of the LCs, e.g., at the end of the plateau emission or where a jet break is identified.

 

Though many studies suggest the positive effects of gamification on participants’ learning and motivation, limited research has examined the basic psychological needs satisfaction in gamified learning. Based on self-determination theory (SDT), this study examined students’ actual competence, perceived competence, perceived autonomy, and perceived relatedness in a gamified math practice. The results showed that students had varied degree of needs satisfaction in perceived competence, perceived autonomy, and perceived relatedness. The implications and significance of the study provide practical teaching implementation suggestions and research insights for gamification research.