University of Kentucky

About: University of Kentucky is a education organization based out in Lexington, Kentucky, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 43933 authors who have published 92195 publications receiving 3256087 citations. The organization is also known as: UK.

Novel Jeff=1/2 Mott state induced by relativistic spin-orbit coupling in Sr2IrO4.

Abstract: We investigated the electronic structure of 5d transition-metal oxide Sr2IrO4 using angle-resolved photoemission, optical conductivity, x-ray absorption measurements, and first-principles band calculations. The system was found to be well described by novel effective total angular momentum Jeff states, in which the relativistic spin-orbit coupling is fully taken into account under a large crystal field. Despite delocalized Ir 5d states, the Jeff states form such narrow bands that even a small correlation energy leads to the Jeff=1/2 Mott ground state with unique electronic and magnetic behaviors, suggesting a new class of Jeff quantum spin driven correlated-electron phenomena.

A comparison of warfarin and aspirin for the prevention of recurrent ischemic stroke.

Abstract: Background Despite the use of antiplatelet agents, usually aspirin, in patients who have had an ischemic stroke, there is still a substantial rate of recurrence. Therefore, we investigated whether warfarin, which is effective and superior to aspirin in the prevention of cardiogenic embolism, would also prove superior in the prevention of recurrent ischemic stroke in patients with a prior noncardioembolic ischemic stroke. Methods In a multicenter, double-blind, randomized trial, we compared the effect of warfarin (at a dose adjusted to produce an international normalized ratio of 1.4 to 2.8) and that of aspirin (325 mg per day) on the combined primary end point of recurrent ischemic stroke or death from any cause within two years. Results The two randomized study groups were similar with respect to base-line risk factors. In the intention-to-treat analysis, no significant differences were found between the treatment groups in any of the outcomes measured. The primary end point of death or recurrent ischemi...

Overview of the SDSS-IV MaNGA Survey: Mapping nearby Galaxies at Apache Point Observatory

Abstract: We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one of three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. MaNGA will investigate the internal kinematic structure and composition of gas and stars in an unprecedented sample of 10,000 nearby galaxies. We summarize essential characteristics of the instrument and survey design in the context of MaNGA's key science goals and present prototype observations to demonstrate MaNGA's scientific potential. MaNGA employs dithered observations with 17 fiber-bundle integral field units that vary in diameter from 12'' (19 fibers) to 32'' (127 fibers). Two dual-channel spectrographs provide simultaneous wavelength coverage over 3600-10300 A at R ~ 2000. With a typical integration time of 3 hr, MaNGA reaches a target r-band signal-to-noise ratio of 4-8 (A–1 per 2'' fiber) at 23 AB mag arcsec–2, which is typical for the outskirts of MaNGA galaxies. Targets are selected with M * 109 M ☉ using SDSS-I redshifts and i-band luminosity to achieve uniform radial coverage in terms of the effective radius, an approximately flat distribution in stellar mass, and a sample spanning a wide range of environments. Analysis of our prototype observations demonstrates MaNGA's ability to probe gas ionization, shed light on recent star formation and quenching, enable dynamical modeling, decompose constituent components, and map the composition of stellar populations. MaNGA's spatially resolved spectra will enable an unprecedented study of the astrophysics of nearby galaxies in the coming 6 yr.