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Peer mentoring programs can provide instructional support for graduate teaching assistants (GTAs) (Rogers & Yee, 2018; Yee & Rogers, 2017) through more specialized and detailed discussions than just working with faculty (Speer et al., 2015; Yee & Rogers, 2016). Lanius et al. (2022) explored how mentees and mentors participating in a comprehensive multi-component GTA pedagogical training program, Promoting Success in Undergraduate Mathematics Through Graduate Teacher Training (Harrell-Williams et al., 2020), at three universities at the start of an academic year conceptualized the role of an effective mentor. In this poster, we explore whether this conceptualization of the mentor role changed over the course of the academic year after participation in components of the training program: a GTA Teaching Seminar, Critical Issues Seminar, and peer mentoring (including mentor training). 

Graduate student peer-mentoring programs benefit participants by providing unique academic, social, psychological, and career development opportunities (Lorenzatti et al., 2019). However, the positive effects of research-oriented peer-mentoring programs are much better understood than teaching-oriented ones. In our poster, we consider mentees and mentors’ perceptions of effective mentoring in a teaching-oriented peer mentorship program. 

Application of massive multiple-input multipleoutput (MIMO) systems to frequency division duplex (FDD) is challenging mainly due to the considerable overhead required for downlink training and feedback. Channel extrapolation, i.e., estimating the channel response at the downlink frequency band based on measurements in the disjoint uplink band, is a promising solution to overcome this bottleneck. This paper presents measurement campaigns obtained by using a wideband (350 MHz) channel sounder at 3.5 GHz composed of a calibrated 64 element antenna array, in both an anechoic chamber and outdoor environment. The Space Alternating Generalized Expectation-Maximization (SAGE) algorithm was used to extract the parameters (amplitude, delay, and angular information) of the multipath components from the attained channel data within the “training” (uplink) band. The channel in the downlink band is then reconstructed based on these path parameters. The performance of the extrapolated channel is evaluated in terms of mean squared error (MSE) and reduction of beamforming gain (RBG) in comparison to the “ground truth”, i.e., the measured channel at the downlink frequency. We find strong sensitivity to calibration errors and model mismatch, and also find that performance depends on propagation conditions: LOS performs significantly better than NLOS. 

Abstract A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with gravitational wave (GW) events from the LIGO/Virgo runs O1 to O3 is conducted with the Pierre Auger Observatory. Due to the distinctive properties of photon interactions and to the background expected from hadronic showers, a subset of the most interesting GW events is selected based on their localization quality and distance. Time periods of 1000 s around and 1 day after the GW events are analyzed. No coincidences are observed. Upper limits on the UHE photon fluence from a GW event are derived that are typically at ∼7 MeV cm −2 (time period 1000 s) and ∼35 MeV cm −2 (time period 1 day). Due to the proximity of the binary neutron star merger GW170817, the energy of the source transferred into UHE photons above 40 EeV is constrained to be less than 20% of its total GW energy. These are the first limits on UHE photons from GW sources.