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  1. Corlu, CG ; Hunter, SR ; Lam, H ; Onggo, BS ; Shortle, J ; Biller, B. (Ed.)
    Calibration is a crucial step for model validity, yet its representation is often disregarded. This paper proposes a two-stage approach to calibrate a model that represents target data by identifying multiple diverse parameter sets while remaining computationally efficient. The first stage employs a black-box optimization algorithm to generate near-optimal parameter sets, the second stage clusters the generated parameter sets. Five black-box optimization algorithms, namely, Latin Hypercube Sampling (LHS), Sequential Model-based Algorithm Configuration (SMAC), Optuna, Simulated Annealing (SA), and Genetic Algorithm (GA), are tested and compared using a disease-opinion compartmental model with predicted health outcomes. Results show that LHS and Optuna allow more exploration and capture more variety in possible future health outcomes. SMAC, SA, and GA, are better at finding the best parameter set but their sampling approach generates less diverse model outcomes. This two-stage approach can reduce computation time while producing robust and representative calibration. 
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    Free, publicly-accessible full text available February 1, 2025
  2. Abstract

    We present a comprehensive study of the nonproportionality of NaI(Tl) scintillation detectors within the context of dark matter search experiments. Our investigation, which integrates COSINE-100 data with supplementary$$\gamma $$γspectroscopy, measures light yields across diverse energy levels from full-energy$$\gamma $$γpeaks produced by the decays of various isotopes. These$$\gamma $$γpeaks of interest were produced by decays supported by both long and short-lived isotopes. Analyzing peaks from decays supported only by short-lived isotopes presented a unique challenge due to their limited statistics and overlapping energies, which was overcome by long-term data collection and a time-dependent analysis. A key achievement is the direct measurement of the 0.87 keV light yield, resulting from the cascade following electron capture decay of$$\mathrm {^{22}Na}$$22Nafrom internal contamination. This measurement, previously accessible only indirectly, deepens our understanding of NaI(Tl) scintillator behavior in the region of interest for dark matter searches. This study holds substantial implications for background modeling and the interpretation of dark matter signals in NaI(Tl) experiments.

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    The Merian survey is mapping ∼ 850 deg2 of the Hyper Suprime-Cam Strategic Survey Program (HSC-SSP) wide layer with two medium-band filters on the 4-m Victor M. Blanco telescope at the Cerro Tololo Inter-American Observatory, with the goal of carrying the first high signal-to-noise (S/N) measurements of weak gravitational lensing around dwarf galaxies. This paper presents the design of the Merian filter set: N708 (λc = 7080 Å, Δλ = 275 Å) and N540 (λc = 5400 Å, Δλ = 210 Å). The central wavelengths and filter widths of N708 and N540 were designed to detect the $\rm H\alpha$ and $\rm [OIII]$ emission lines of galaxies in the mass range $8\lt \rm \log M_*/M_\odot \lt 9$ by comparing Merian fluxes with HSC broad-band fluxes. Our filter design takes into account the weak lensing S/N and photometric redshift performance. Our simulations predict that Merian will yield a sample of ∼ 85 000 star-forming dwarf galaxies with a photometric redshift accuracy of σΔz/(1 + z) ∼ 0.01 and an outlier fraction of $\eta =2.8~{{\ \rm per\ cent}}$ over the redshift range 0.058 < z < 0.10. With 60 full nights on the Blanco/Dark Energy Camera (DECam), the Merian survey is predicted to measure the average weak lensing profile around dwarf galaxies with lensing S/N ∼32 within r < 0.5 Mpc and lensing S/N ∼90 within r < 1.0 Mpc. This unprecedented sample of star-forming dwarf galaxies will allow for studies of the interplay between dark matter and stellar feedback and their roles in the evolution of dwarf galaxies.

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  4. Free, publicly-accessible full text available June 30, 2024
  5. Abstract

    We propose a new measurement of the ratio of positron-proton to electron-proton elastic scattering at DESY. The purpose is to determine the contributions beyond single-photon exchange, which are essential for the Quantum Electrodynamic (QED) description of the most fundamental process in hadronic physics. By utilizing a 20 cm long liquid hydrogen target in conjunction with the extracted beam from the DESY synchrotron, we can achieve an average luminosity of$$2.12\times 10^{35}$$2.12×1035 cm$$^{-2}\cdot $$-2·s$$^{-1}$$-1 ($$\approx 200$$200times the luminosity achieved by OLYMPUS). The proposed two-photon exchange experiment (TPEX) entails a commissioning run at a beam energy of 2 GeV, followed by measurements at 3 GeV, thereby providing new data up to$$Q^2=4.6$$Q2=4.6 (GeV/c)$$^2$$2(twice the range of current measurements). We present and discuss the proposed experimental setup, run plan, and expectations.

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  6. For short-wavelength infrared (SWIR) avalanche photodiodes, a separate absorption, charge, and multiplication design is widely used. AlInAsSb on an InP substrate is a potential multiplication layer with a lattice match to absorber candidates across the SWIR. Our new measurements demonstrate that AlInAsSb on InP is a promising multiplier candidate with a relatively low dark current density of 10−4 A/cm2 at a gain of 30; a high gain, measured up to 245 in this study; and a large differentiation of electron and hole ionization leading to a low excess noise, measured to be 2.5 at a gain of 30. These characteristics are all improvements over commercially available SWIR detectors incorporating InAlAs or InP as the multiplier. We measured and analyzed gain for multiple wavelengths to extract the ionization coefficients as a function of an electric field over the range 0.33–0.6 MV/cm.

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    Free, publicly-accessible full text available September 25, 2024
  7. This commentary paper addresses the outdated and misleading terminology used to categorize termites into “higher” and “lower”. These terms perpetuate a linear progression view of evolution, which is both inaccurate and detrimental to our understanding of the diversity of life. We trace the historical origins of these terms and highlight their flawed interpretation of evolutionary relationships. We advocate for the adoption of Termitidae (or termitid), rather than “higher termites”. As for the paraphyletic group of “lower termites”, we recommend refraining from grouping them together, unless specifically referring to their symbionts. In such cases, we propose “protist-dependent termites” or “non-Termitidae termites”. 
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    Free, publicly-accessible full text available September 1, 2024
  8. Achieving Change in our Communities for Equity and Student Success (ACCESS) in STEM at the University of Washington Tacoma started as a Track 1 S-STEM program in 2018 and has supported 69 students to date. This year we received Track 2 funding and welcomed our fifth cohort to campus, with funding to support ~32 additional students through 2026. University of Washington Tacoma is an Asian American and Native American Pacific Islander-serving institution (AANAPISI), and we serve a high proportion of racial minority and first generation college students. Our ACCESS scholars are pursuing bachelor’s degrees in Mathematics, Environmental Science, Biomedical Sciences, Information Technology, Computer Science and Systems, Computer Engineering and Systems, Electrical Engineering, Mechanical Engineering, and Civil Engineering, with Computer Science and Engineering representing over 60% of ACCESS scholars to date. First-time college students and first-year transfer students receive full scholarships for their first two years, and partial scholarships for their third and fourth years. The project includes an optional Early Fall Math course to enhance entry into STEM majors, and participants are able to engage in a Research Experience or project-based Introduction to Engineering course in their first year. Coupled with individual faculty mentoring and an on-campus STEM living learning community, the quarterly Success in STEM seminar course helps scholars form a cohesive community through group mentoring, as well as develop a sense of belonging, identity, and empowerment to transform the culture of STEM. This program is distinguished by its focus on pre-STEM majors in their first and second years on campus, and includes mentor training for ~30-40 faculty in teaching and mentoring diverse student populations, thus impacting all students in our majors. Our goal was to evaluate the effectiveness of a program that focuses on the first two years of college and provides financial support, courses to introduce students to research and project-based engineering, and intensive mentoring in increasing retention and academic success for Computer Science and Engineering (CS+E) students, and whether this program helps to close equity gaps for CS+E students who are low socioeconomic status (SES), underrepresented minorities (URMs), female, and/or first generation in college (First Gen) students. We compared our student scholars to a comparison group of students who met eligibility requirements but did not participate in the program. Program scholars had higher first and second year retention, and had significantly higher GPAs. The pandemic resulted in significant social, emotional, and economic stresses for our program scholars, which may have heightened the impact of the ACCESS in STEM program. 
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    Free, publicly-accessible full text available June 1, 2024
  9. Research has highlighted that actively involving students during instruction can lead to positive outcomes for students. However, college mathematics instructors may need support to develop the knowledge and skills necessary to effectively implement this type of instruction. This study looks at how college algebra instructors in a grant-supported professional learning community (PLC) focus on different aspects of their own and others’ teaching. We leverage the instructional triangle as an analytical framework to characterize the foci of participants’ observations. We analyzed PLC meetings where participants reported on specific aspects of each other’s observed classes. Our analysis revealed that instructors each had a primary focus that drove their observations. We anticipate these different foci will inform future PLC meetings and lead to new questions about instructor thinking, and to continued development of the instructional triangle. 
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    The Vera C. Rubin Observatory Wide-Fast Deep sky survey will reach unprecedented surface brightness depths over tens of thousands of square degrees. Surface brightness photometry has traditionally been a challenge. Current algorithms which combine object detection with sky estimation systematically oversubtract the sky, biasing surface brightness measurements at the faint end and destroying or severely compromising low surface brightness light. While it has recently been shown that properly accounting for undetected faint galaxies and the wings of brighter objects can in principle recover a more accurate sky estimate, this has not yet been demonstrated in practice. Obtaining a consistent spatially smooth underlying sky estimate is particularly challenging in the presence of representative distributions of bright and faint objects. In this paper, we use simulations of crowded and uncrowded fields designed to mimic Hyper Suprime-Cam data to perform a series of tests on the accuracy of the recovered sky. Dependence on field density, galaxy type, and limiting flux for detection are all considered. Several photometry packages are utilized: source extractor, gnuastro, and the LSST science pipelines. Each is configured in various modes, and their performance at extreme low surface brightness analysed. We find that the combination of the source extractor software package with novel source model masking techniques consistently produce extremely faint output sky estimates, by up to an order of magnitude, as well as returning high fidelity output science catalogues.

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