Photoexcited Small Polaron Formation in Goethite (α-FeOOH) Nanorods Probed by Transient Extreme Ultraviolet Spectroscopy

Small polaron formation limits the mobility and lifetimes of photoexcited carriers in metal oxides. As the ligand field strength increases, the carrier mobility decreases, but the effect on the photoexcited small polaron formation is still unknown. Extreme ultraviolet transient absorption spectroscopy is employed to measure small polaron formation rates and probabilities in goethite (α-FeOOH) crystalline nanorods at pump photon energies from 2.2 to 3.1 eV. The measured polaron formation time increases with excitation photon energy from 70 ± 10 fs at 2.2 eV to 350 ± 30 fs at 2.6 eV, whereas the polaron formation probability (85 ± 10%) remains constant. By comparison to hematite (α-Fe_2O_3), an oxide analogue, the role of ligand composition and metal center density in small polaron formation time is discussed. This work suggests that incorporating small changes in ligands and crystal structure could enable the control of photoexcited small polaron formation in metal oxides

LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler Mission

We report the discovery of a brown dwarf that transits one member of the M+M binary system LHS6343AB every 12.71 days. The transits were discovered using photometric data from the Kelper public data release. The LHS6343 stellar system was previously identified as a single high-proper-motion M dwarf. We use high-contrast imaging to resolve the system into two low-mass stars with masses 0.45 Msun and 0.36 Msun, respectively, and a projected separation of 55 arcsec. High-resolution spectroscopy shows that the more massive component undergoes Doppler variations consistent with Keplerian motion, with a period equal to the transit period and an amplitude consistent with a companion mass of M_C = 62.8 +/- 2.3 Mjup. Based on an analysis of the Kepler light curve we estimate the radius of the companion to be R_C = 0.832 +/- 0.021 Rjup, which is consistent with theoretical predictions of the radius of a > 1 Gyr brown dwarf.Comment: Our previous analysis neglected the dependence of the scaled semimajor axis, a/R, on the transit depth. By not correcting a/R for the third-light contamination, we overestimated the mass of Star A, which led to an overestimate the mass and radius of the LHS6343

Characterizing the Cool KOIs II. The M Dwarf KOI-254 and its Hot Jupiter

We report the confirmation and characterization of a transiting gas giant planet orbiting the M dwarf KOI-254 every 2.455239 days, which was originally discovered by the Kepler mission. We use radial velocity measurements, adaptive optics imaging and near infrared spectroscopy to confirm the planetary nature of the transit events. KOI-254b is the first hot Jupiter discovered around an M-type dwarf star. We also present a new model-independent method of using broadband photometry to estimate the mass and metallicity of an M dwarf without relying on a direct distance measurement. Included in this methodology is a new photometric metallicity calibration based on J-K colors. We use this technique to measure the physical properties of KOI-254 and its planet. We measure a planet mass of Mp = 0.505 Mjup, radius Rp = 0.96 Rjup and semimajor axis a = 0.03 AU, based on our measured stellar mass Mstar = 0.59 Msun and radius Rstar = 0.55 Rsun. We also find that the host star is metal-rich, which is consistent with the sample of M-type stars known to harbor giant planets.Comment: AJ accepted (in press

Research-related Curriculum and its Applications in US College of Pharmacy Programs

Class of 2019 Abstract, Poster, and PaperSpecific Aims: To quantify the number of PharmD programs that require completion of a research project. To describe the types of research being undertaken within PharmD programs. To compare current responses with those obtained in the last survey (2007). Methods: Collaborative effort including students and faculty at three pharmacy programs (AZ, FL and MI). Cross-sectional analysis utilizing the survey (with modifications) developed in 2007. Peer review of questions (face-validity); format included dichotomous response, multiple-choice, and open response. Qualtrics® survey distributed via email to Academic Affairs (or comparative) Dean at AACP affiliate institutions. Descriptive analyses; duplicate responses combined when possible. Project was deemed exempt by IRB. Main Results: Seventy-four programs responded (54% response rate). A total of 22 (30%) programs have a required student research project compared to 25% in 2007. Project requirements were similar among the programs requiring a project: proposal (95%), IRB application (90%), collect and analyze data (77%), prepare a written report (86%), and present findings (82%). The most common methods of collecting data were surveys (91%) and chart reviews (86%). Research related coursework was similar between programs except for research methods courses, which were 36% among programs requiring a research project, and 14% among those not requiring a project. Conclusions: The number of programs requiring student research appears to have increased since 2007. Based on the survey data, students could expect to have similar research experiences in any of the colleges requiring a research project. Most colleges provide coursework related to research.This item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Librarian and Clinical Instructor, Pharmacy Practice and Science, [email protected]