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Japanese Rhinoceros beetles (Trypoxylus dichotomous), known primarily for their large horns, are a classic example of ornate weaponry produced through sexual selection. The male beetle’s prominent horns are used in maletomale combat for dominance and access to females. Observations in the lab and the field suggest that multiple forms of signaling are also involved in both the aggressive interactions and female mate choice. One such signal seems to be the songs created through male abdominal stridulation. Males perform both an alarmstyle chirp (also seen in aggressive interactions) and rhythmic “purring” prior to copulation attempts. Several questions arise in relation to this behavior and its effect on mating outcomes: Is there a relationship between song characteristics and morphological characteristics? Can vibrations be transmitted through the surrounding substrate? Is there a relationship between song characteristics and courtship outcomes? To analyze these songs in the field, a Polytech VibroGo VG200 laser vibrometer was used to measure the velocity of both the male’s elytra and surrounding tree bark during courtship. Vibrational amplitude and periodicity, corresponding location, beetle characteristics, and courtship details were collected. Male courtship song characteristics will be compared to morphological variables, as well as courtship outcomes. Substrate vibration transmission and attenuation will also be discussed.more » « less

We present a fast, differentially private algorithm for highdimensional covarianceaware mean estimation with nearly optimal sample complexity. Only exponentialtime estimators were previously known to achieve this guarantee. Given n samples from a (sub)Gaussian distribution with unknown mean μ and covariance Σ, our (ϵ,δ)differentially private estimator produces μ~ such that ∥μ−μ~∥Σ≤α as long as n≳dα2+dlog1/δ√αϵ+dlog1/δϵ. The Mahalanobis error metric ∥μ−μ^∥Σ measures the distance between μ^ and μ relative to Σ; it characterizes the error of the sample mean. Our algorithm runs in time O~(ndω−1+nd/\eps), where ω<2.38 is the matrix multiplication exponent.We adapt an exponentialtime approach of Brown, Gaboardi, Smith, Ullman, and Zakynthinou (2021), giving efficient variants of stable mean and covariance estimation subroutines that also improve the sample complexity to the nearly optimal bound above.Our stable covariance estimator can be turned to private covariance estimation for unrestricted subgaussian distributions. With n≳d3/2 samples, our estimate is accurate in spectral norm. This is the first such algorithm using n=o(d2) samples, answering an open question posed by Alabi et al. (2022). With n≳d2 samples, our estimate is accurate in Frobenius norm. This leads to a fast, nearly optimal algorithm for private learning of unrestricted Gaussian distributions in TV distance.Duchi, Haque, and Kuditipudi (2023) obtained similar results independently and concurrently.more » « less

Balance problems affect more than eight million adults, and the percentage of balance problems increases with age. Globally, the population is aging, making balance problems a relevant topic of investigation. Balance impairments are the primary cause of falls, which result in debilitating injuries, especially for the elderly population. There is a significant opportunity for students in engineering and other disciplines to explore and contribute to research and education in this area. In this work, a group of graduate students from electrical, industrial, and mechanical engineering present research that will be mapped into an educational module on this topic. This module is cocreated with faculty and domain experts. Sensors of various types are being investigated for monitoring gait and identifying the propensity for losing balance. A survey of the state of the art of sensor technology pertaining to balance is conducted. Models of human balance during quiet standing are investigated. An interactive simulation tool is developed to allow students to vary the model parameters and gain an intuitive understanding of the engineering principles involved. For engineering students, this offers many opportunities to better understand how topics they study in engineering courses relate to a significant societal problem. For students in courses such as statics, dynamics, and control systems, the concepts of change in the center of mass, the center of pressure, the inverted pendulum, and stability can be reinforced in relation to the balance dynamics problem. This paper describes the framework that will be used in an educational module that will improve undergraduate engineering concepts through balance dynamics experiments and simulations, and present interdisciplinary research problems to graduate students. This study contributes to an Innovations in Graduate Education National Science Foundation research project.more » « less

Abstract HESS J1809193 is an unidentified TeV source, first detected by the High Energy Stereoscopic System (H.E.S.S.) collaboration. The emission originates in a sourcerich region that includes several supernova remnants (SNRs) and pulsars including SNR G11.1+0.1, SNR G11.00.0, and the young radio pulsar PSR J18091917. Originally classified as a pulsar wind nebula candidate, recent studies show the peak of the TeV region overlapping with a system of molecular clouds. This resulted in the revision of the original leptonic scenario to look for alternate hadronic scenarios. Marked as a potential PeVatron candidate, this region has been studied extensively by H.E.S.S. due to its emission extending up to several tens of TeV. In this work, we use 2398 days of data from the High Altitude Water Cherenkov (HAWC) observatory to carry out a systematic source search of the HESS J1809193 region. We were able to resolve emission detected as an extended component (modelled as a symmetric Gaussian with a 1
σ radius of 0.°21) with no clear cutoff at high energies and emitting photons up to 210 TeV. We model the multiwavelength observations for the region around HESS J1809193 using a timedependent leptonic model and a leptohadronic model. Our model indicates that both scenarios could explain the observed data within the region of HESS J1809193.Free, publiclyaccessible full text available August 22, 2025 
We present results of the detailed study of several hundred Hamamatsu H12700 Multianode Photomultiplier Tubes (MaPMTs), characterizing their response to the Cherenkov light photons in the second Ring Imaging Cherenkov detector, a part of the CLAS12 upgrade at Jefferson Lab. The total number of pixels studied was 25536. The single photoelectron spectra were measured for each pixel at different high voltages and light intensities of the laser test setup. Using the same dedicated frontend electronics as in the first RICH detector, the setup allowed us to characterize each pixel’s properties such as gain, quantum efficiency, signal crosstalk between neighboring pixels, and determine the signal threshold values to optimize their efficiency to detect Cherenkov photons. A recently published stateoftheart mathematical model, describing photon detector response functions measured in low light conditions, was extended to include the description of the crosstalk contributions to the spectra. The database of extracted parameters will be used for the final selection of the MaPMTs, their arrangement in the new RICH detector, and the optimization of the operational settings of the frontend electronics. The results show that the characteristics of the H12700 MaPMTs satisfy our requirements for the positionsensitive single photoelectron detectors.more » « less

Abstract Galactic cosmic rays (GCRs) are charged particles that reach the heliosphere almost isotropically in a wide energy range. In the inner heliosphere, the GCR flux is modulated by solar activity so that only energetic GCRs reach the lower layers of the solar atmosphere. In this work, we propose that highenergy GCRs can be used to explore the solar magnetic fields at low coronal altitudes. We used GCR data collected by the HighAltitude Water Cherenkov observatory to construct maps of GCR flux coming from the Sun’s sky direction and studied the observed GCR deficit, known as Sun shadow (SS), over a 6 yr period (2016–2021) with a time cadence of 27.3 days. We confirm that the SS is correlated with sunspot number, but we focus on the relationship between the photospheric solar magnetic field measured at different heliolatitudes and the relative GCR deficit at different energies. We found a linear relationship between the relative deficit of GCRs represented by the depth of the SS and the solar magnetic field. This relationship is evident in the observed energy range of 2.5–226 TeV, but is strongest in the range of 12.4 33.4 TeV, which implies that this is the best energy range to study the evolution of magnetic fields in the low solar atmosphere.
Free, publiclyaccessible full text available April 25, 2025 
ABSTRACT The latetime integrated SachsWolfe (ISW) imprint of $R\gtrsim 100~h^{1}\, \mathrm{Mpc}$ superstructures is sourced by evolving largescale potentials due to a dominant dark energy component in the ΛCDM model. The aspect that makes the ISW effect distinctly interesting is the repeated observation of strongerthanexpected imprints from supervoids at z ≲ 0.9. Here we analyse the unprobed key redshift range 0.8 < z < 2.2 where the ISW signal is expected to fade in ΛCDM, due to a weakening dark energy component, and eventually become consistent with zero in the matter dominated epoch. On the contrary, alternative cosmological models, proposed to explain the excess lowz ISW signals, predicted a signchange in the ISW effect at z ≈ 1.5 due to the possible growth of largescale potentials that is absent in the standard model. To discriminate, we estimated the highz ΛCDM ISW signal using the Millennium XXL mock catalogue, and compared it to our measurements from about 800 supervoids identified in the eBOSS DR16 quasar catalogue. At 0.8 < z < 1.2, we found an excess ISW signal with AISW ≈ 3.6 ± 2.1 amplitude. The signal is then consistent with the ΛCDM expectation (AISW = 1) at 1.2 < z < 1.5 where the standard and alternative models predict similar amplitudes. Most interestingly, we also observed an oppositesign ISW signal at 1.5 < z < 2.2 that is in 2.7σ tension with the ΛCDM prediction. Taken at face value, these recurring hints for ISW anomalies suggest an alternative growth rate of structure in lowdensity environments at $\sim 100~h^{1}\, \mathrm{Mpc}$ scales.