Local Electronic and Magnetic Studies of an Artificial La2FeCrO6 Double Perovskite

Through the utilization of element-resolved polarized x-ray probes, the electronic and magnetic state of an artificial La2FeCrO6 double perovskite were explored. Applying unit-cell level control of thin film growth on SrTiO3 (111), the rock salt double perovskite structure can be created for this system, which does not have an ordered perovskite phase in the bulk. We find that the Fe and Cr are in the proper 3+ valence state, but, contrary to previous studies, the element-resolved magnetic studies find the moments in field are small and show no evidence of a sizable magnetic moment in the remanent state.Comment: 3 pages, 4 figure

Flaher for Wind Ensemble

Music compositions are vehicles of communication. Organized music ensembles in schools allow for students to share in the process of music-making and extramusical expression within the curriculum. As of late, school districts have made a push in mental health awareness and suicide prevention within professional development seminars. This project views the music classroom as an important, open environment for such pressing social subjects. In such, my composition—Flaher (pronounced “flare”)—pays homage to a friend, Anthony Flaherty, who committed suicide (keeping his namesake in the work’s title). Flaher is an accessible piece for high school or college band that directors can use to discuss pressing challenges in students’ lives. The work explores melodies derived from a chord of solace discovered in the coping process after hearing of the suicide. These melodies are presented in the alto flute, representing the initials—A.F.—of my friend. This theme is then developed throughout the band. The theme undergoes formal contrapuntal techniques to create a varied aural landscape leading to melancholy remembrance. Flaher was premiered by the WKU Wind Ensemble at their April concert, with hopes of being published soon thereafter

Response of Photoluminescence of H-Terminated and Hydrosilylated Porous Si Powders to Rinsing and Temperature

The photoluminescence (PL) response of porous Si has potential applications in a number of sensor and bioimaging techniques. However, many questions still remain regarding how to stabilize and enhance the PL signal, as well as how PL responds to environmental factors. Regenerative electroless etching (ReEtching) was used to produce photoluminescent porous Si directly from Si powder. As etched, the material was H-terminated. The intensity and peak wavelength were greatly aected by the rinsing protocol employed. The highest intensity and bluest PL were obtained when dilute HCl(aq) rinsing was followed by pentane wetting and vacuum oven drying. Roughly half of the hydrogen coverage was replaced with –RCOOH groups by thermal hydrosilylation. Hydrosilylated porous Si exhibited greater stability in aqueous solutions than H-terminated porous Si. Pickling of hydrosilylated porous Si in phosphate buer was used to increase the PL intensity without significantly shifting the PL wavelength. PL intensity, wavelength and peak shape responded linearly with temperature change in a manner that was specific to the surface termination, which could facilitate the use of these parameters in a dierential sensor scheme that exploits the inherent inhomogeneities of porous Si PL response

Empirical ugri-UBVRc Transformations for Galaxies

We present empirical color transformations between Sloan Digital Sky Survey ugri and Johnson-Cousins UBVRc photometry for nearby galaxies (D < 11 Mpc). We use the Local Volume Legacy (LVL) galaxy sample where there are 90 galaxies with overlapping observational coverage for these two filter sets. The LVL galaxy sample consists of normal, non-starbursting galaxies. We also examine how well the LVL galaxy colors are described by previous transformations derived from standard calibration stars and model-based galaxy templates. We find significant galaxy color scatter around most of the previous transformation relationships. In addition, the previous transformations show systematic offsets between transformed and observed galaxy colors which are visible in observed color-color trends. The LVL-based $galaxy$ transformations show no systematic color offsets and reproduce the observed color-color galaxy trends.Comment: Accepted for publication in MNRAS (9 pages, 6 figures, 4 tables

Spitzer Local Volume Legacy (LVL) SEDs and Physical Properties

We present the panchromatic spectral energy distributions (SEDs) of the Local Volume Legacy (LVL) survey which consists of 258 nearby galaxies ($D<$11 Mpc). The wavelength coverage spans the ultraviolet to the infrared (1500 $\textrm{\AA}$ to 24 $\mu$m) which is utilized to derive global physical properties (i.e., star formation rate, stellar mass, internal extinction due to dust.). With these data, we find color-color relationships and correlated trends between observed and physical properties (i.e., optical magnitudes and dust properties, optical color and specific star formation rate, and ultraviolet-infrared color and metallicity). The SEDs are binned by different galaxy properties to reveal how each property affects the observed shape of these SEDs. In addition, due to the volume-limited nature of LVL, we utilize the dwarf-dominated galaxy sample to test star formation relationships established with higher-mass galaxy samples. We find good agreement with the star-forming "main-sequence" relationship, but find a systematic deviation in the infrared "main-sequence" at low luminosities. This deviation is attributed to suppressed polycyclic aromatic hydrocarbon (PAH) formation in low metallicity environments and/or the destruction of PAHs in more intense radiation fields occurring near a suggested threshold in sSFR at a value of log($sSFR$) $\sim$ $-$10.2.Comment: Accepted for publication in MNRAS (15 pages, 14 figures, 1 table

The California Legacy Survey IV. Lonely, Poor, and Eccentric: A Comparison Between Solitary and Neighborly Gas Giants

We compare systems with single giant planets to systems with multiple giant planets using a catalog of planets from a high-precision radial velocity survey of FGKM stars. Our comparison focuses on orbital properties, planet masses, and host star properties. We use hierarchical methods to model the orbital eccentricity distributions of giant singles and giant multis, and find that the distributions are distinct. The multiple giant planets typically have moderate eccentricities and their eccentricity distribution extends to $e=0.47$ (90th percentile), while the single giant planets have a pile-up of nearly circular orbits and a long tail that extends to $e=0.77$. We determine that stellar hosts of multiple giants are distinctly more metal-rich than hosts of solitary giants, with respective mean metallicities $0.228\pm0.027$ vs. $0.129\pm0.019$ dex. We measure the distinct occurrence distributions of single and multiple giants with respect to orbital separation, and find that single gas giants have a $\sim$2.3$\sigma$ significant hot ($a<0.06$) Jupiter pile-up not seen among multi giant systems. We find that the median mass (\msini ) of giants in multiples is nearly double that of single giants (1.71 \mjup vs. 0.92 \mjup ). We find that giant planets in the same system have correlated masses, analogous to the `peas in a pod' effect seen among less massive planets

Generative AI versus Faculty-Facilitated Scenario-Based Simulation Design by Medical Students

Introduction: Interest in generative AI and its application to various disciplines, including medical education, has been exponentially growing. ChatGPT was released in 2022 and has garnered much attention due to its free public access. However, research exploring its use to design scenario-based simulations (SBSs) is limited. Rodgers’ Simulation in Healthcare article (2023) describes ChatGPT’s potential as a useful tool for simulationists to streamline instructional design. Yet, they underscore the crucial role of human intervention in addressing shortcomings related to errors, complexity, and formatting. A background in simulation educational design may be a prerequisite. Often when SBS design is undertaken by novice simulationists, the process can be overwhelming and the instructional design may be incomplete, especially without the guidance of experienced simulationists. The applicability of ChatGPT in aiding non-simulationists with SBS design in healthcare education has not been explored. Objective: To describe the instructional design process and outcomes of SBS created by medical students using ChatGPT and compare them to SBS created by medical students with simulation-expert faculty guidance. Methods: Five existing SBSs designed by medical student interest groups (SIG) with simulation faculty guidance were collected from simulation center archives, and scenario goals and patient synopsis were extracted. Medical students unfamiliar with the complete scenario details used the extracted goals and synopsis to create new scenarios using ChatGPT. A blank scenario design template outlining essential elements was used for reference. The ChatGPT conversation tool facilitated iterative refinement of missing elements, errors, or desired modifications. Five scenarios were produced in one session, with elapsed time recorded. The number of design elements and objectives were quantified and compared to the scenarios crafted by SIGs; analysis employed a two-tailed T-test. Results: On average (n=5), the ChatGPT scenarios design time was 37±11.8 minutes and 5.8±1.3 prompts were needed to produce the final scenario. In contrast, SBSs designed by SIGs with faculty input were created over months, and required multiple faculty-student meetings. ChatGPT produced an average of 4.0±0.7 learning objectives, compared to 3.2±1.6 when developed with faculty. ChatGPT’s objectives were often repetitions of the initial input goals. ChatGPT fulfilled an average of 11.8±0.8 out of 18 template elements, compared to 12.8±3.8 in faculty-guided scenarios. Discussion: The most notable difference between ChatGPT and faculty guided scenarios is substantial reduction in creation time. AI-assisted scenarios were created in mere minutes, while faculty guided scenarios took months to complete. Time efficiency could allow students to jumpstart the design process and time saved could support further simulation refinement under faculty guidance. There were no statistical differences between groups in the number of fulfilled elements (p=0.53) or objectives (p=0.35). However, the quality and accuracy of the ChatGPT scenarios have yet to be examined by simulation experts. Challenges experienced while using ChatGPT include the omission of requested scenario components, inadvertent removal of desired elements during the iterative process, and inconsistencies in formatting between scenarios. Target Audience: Novice and expert simulationists, medical students, faculty<p/

K2-231 b: A sub-Neptune exoplanet transiting a solar twin in Ruprecht 147

We identify a sub-Neptune exoplanet ($R_p = 2.5 \pm 0.2$ R$_\oplus$) transiting a solar twin in the Ruprecht 147 star cluster (3 Gyr, 300 pc, [Fe/H] = +0.1 dex). The ~81 day light curve for EPIC 219800881 (V = 12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ~0.06%, and a duration of ~4 hours. Based on our analysis of high-resolution MIKE spectra, broadband optical and NIR photometry, the cluster parallax and interstellar reddening, and isochrone models from PARSEC, Dartmouth, and MIST, we estimate the following properties for the host star: $M_\star = 1.01 \pm 0.03$ M$_\odot$, $R_\star= 0.95 \pm 0.03$ R$_\odot$, and $T_{\rm eff} = 5695 \pm 50$ K. This star appears to be single, based on our modeling of the photometry, the low radial velocity variability measured over nearly ten years, and Keck/NIRC2 adaptive optics imaging and aperture-masking interferometry. Applying a probabilistic mass-radius relation, we estimate that the mass of this planet is $M_p = 7 +5 -3$ M$_\oplus$, which would cause a RV semi-amplitude of $K = 2 \pm 1$ m s$^{-1}$ that may be measurable with existing precise RV facilities. After statistically validating this planet with BLENDER, we now designate it K2-231 b, making it the second sub-stellar object to be discovered in Ruprecht 147 and the first planet; it joins the small but growing ranks of 23 other planets found in open clusters.Comment: 24 pages, 7 figures, light curve included as separate fil

The Spitzer Local Volume Legacy (LVL) Global Optical Photometry

We present the global optical photometry of 246 galaxies in the Local Volume Legacy (LVL) survey. The full volume-limited sample consists of 258 nearby (D < 11 Mpc) galaxies whose absolute B-band magnitude span a range of -9.6 < M_B < -20.7 mag. A composite optical (UBVR) data set is constructed from observed UBVR and SDSS ugriz imaging, where the ugriz magnitudes are transformed into UBVR. We present photometry within three galaxy apertures defined at UV, optical, and IR wavelengths. Flux comparisons between these apertures reveal that the traditional optical R25 galaxy apertures do not fully encompass extended sources. Using the larger IR apertures we find color-color relationships where later-type spiral and irregular galaxies tend to be bluer than earlier-type galaxies. These data provide the missing optical emission from which future LVL studies can construct the full panchromatic (UV-optical-IR) spectral energy distributions.Comment: Accepted for publication in MNRAS (9 pages, 5 figures, 5 tables