21 research outputs found
Protecting the Past: A Comparative Study of the Antiquities Laws in the Mid-South
Governmental efforts to protect antiquities can be found in the early twentieth century; however, the most significant policy efforts began in the late 1960s and early 1970s. This manuscript focuses on the properties/items protected under current statutes in Arkansas, Louisiana, and Texas and provides background on major federal policies. Moreover, it addresses the penalties imposed for violating these regulations. The efforts made to enforce these rules are also addressed along with suggestions for improving implementation of antiquities policies in all three states
A remarkably unsymmetric hexairon core embraced by two high-symmetry tripodal oligo-α-pyridylamido ligands
Oligo-α-pyridylamides offer an appealing route to polyiron complexes with short Fe-Fe separations and large room temperature magnetic moments. A derivative of tris(2‐aminoethyl)amine (H6tren) containing three oligo-α-pyridylamine branches and thirteen nitrogen donors (H6L) reacts with [Fe2(Mes)4] to yield an organic nanocage built up by two tripodal ligands with interdigitated branches (HMes = mesitylene). The nanocage has crystallographic D3 symmetry but hosts a remarkably unsymmetric hexairon-oxo core, with a central Fe5(μ5-O) square pyramid, two oxygen donors bridging basal sites, and an additional Fe center residing in one of the two tren-like pockets. Bond Valence Sum (BVS) analysis, Density Functional Theory (DFT) calculations, and electrochemical data were then used to establish the protonation state of oxygen atoms and the formal oxidation states of the metals. To this purpose, a specialized set of BVS parameters was devised for Fe2+-N3- bonds with nitrogen donors of oligo-α-pyridylamides. This allowed us to formulate the compound as [Fe6O2(OH)(H3L)L], with nominally four FeII and two FeIII ions. Mössbauer spectra indicate that the compound contains two unique FeII sites, identified as a pair of closely spaced hydroxo-bridged metal ions in the central Fe5(μ5-O) pyramid, and a substantially valence-delocalized FeII2FeIII2 unit. Broken-symmetry DFT calculations predict strong ferromagnetic coupling between the two iron(II) ions, leading to a local S = 4 state that persists to room temperature and explaining the large magnetic moment measured at 300 K. The compound behaves as a single-molecule magnet, with magnetization dynamics detectable in zero static field and dominated by an Orbach-like mechanism with Ueff/kB = 49(2) K and τ0 = 4(2)·10−10 s
NASA Exploration Mission 2 Mission Design
Exploration Mission 2 (EM-2) will be NASAs first manned flight on the Space Launch System (SLS) and Orion Spacecraft. The mission has been changed from an SLS Block 1B configuration to Block 1. This change has necessitated a reexamination of the flight profile to determine what changes must be made in order to accommodate the reduced launch vehicle performance on the Block 1. Launch availability and orbital debris risk will be traded to find the best flight profile for both SLS and Orion
Collage Concert 2021
An exciting highlight of each season, Collage is the signature annual production of the School of Music. All proceeds and donations support student scholarships. This unique production features over 200 student and faculty performers. The featured highlighted ensembles include jazz, orchestra, choir, band, percussion, opera, chamber groups, and much more. This year, Collage is free and you may live-stream the event from the comfort of your home.https://digitalcommons.kennesaw.edu/musicprograms/2368/thumbnail.jp
Timing of Liberation from Ventilation Assistance and Decannulation in Preterm Infants with Bronchopulmonary Dysplasia after Tracheostomy
Liver Assist Systems: State of the Art
peer reviewedAttempts to develop liver support systems for the treatment of patients with liver failure have ranged from use of plasma exchange to utilization of charcoal columns and extracorporeal devices loaded with liver tissue. However, no system has achieved wide clinical use and - in the absence of liver transplantation - severe hepatic failure continues to be associated with significant morbidity and mortality. In this paper, the authors review the current status of liver assist systems and summarize their clinical experience with a xenogeneic cell based-bioartificial liver