Crystal structures and growth mechanism for ultrathin films of ionic compound materials: FeO(111) on Pt(111)

The growth and atomic structures of epitaxial iron-oxide films on Pt(111) were studied with scanning tunneling microscopy and high-resolution low-energy electron diffraction. During the initial layer-by-layer growth of FeO(111) four different structures are formed as the coverage increases to 2.5 monolayers, then a three-dimensional growth of Fe3O4(111) islands begins. The structural transformations demonstrate that the relaxations within the FeO(111) films and the Stranski-Krastanov growth mode are induced by electrostatic surface energies, which dominate the energetics of thin film systems made up of ionic compound materials

Comprehensive Analysis of Arkansas Teacher Salaries: State, Region, and District

School funding has been an area of contention in the courts of nearly every state. Many of these court cases have challenged the constitutionality of state funding formulas, arguing the funding system was inadequate or inequitable because poor urban or rural districts often faced a disadvantage in garnering tax dollars for education. Specific to Arkansas, in the 1983 decision Dupree v. Alma School District, the Arkansas Supreme Court declared the state’s funding system was not meeting its constitutional requirements

Public School Choice and Desegregation in Arkansas

Public school choice is an umbrella term for policies that allow students to enroll in a public school other than their residentially-assigned school. Public school choice, also called openenrollment, is typically divided into two categories: intra-district choice, transfers to schools in the same district, and inter-district choice, transfers to schools in other districts

Outstanding Educational Performance Awards: Highlighting High-Achieving Arkansas Schools, 2013

The GPA measure, we believe, is a better representation of student achievement on statewide standardized exams. In this report, we are presenting a list of the top 25 schools in each area. In some cases, these top 25 lists will contain more than 25 schools as some schools\u27 GPA scores will be identical. This is not a new phenomenon, as we also exceeded 25 schools in previous reports when using the percent proficient and advanced metric as an indicator for student achievement; however, there are fewer ties using the more precise GPA measure. After we present our overall snapshot of high-performing schools, we will release subsequent reports every few weeks focusing on different subsets of schools. For example, in section two of the OEP Awards AER, we will feature schools that are beating the odds (that is, schools that have high levels of student achievement while serving a high percentage of low-income students). In the following weeks, we will focus on high-performing elementary schools, middle schools, and high schools in the various regions across the state. Finally, we will conclude our report by focusing on the schools with the greatest improvement in test scores

Quantum Channels and Representation Theory

In the study of d-dimensional quantum channels $(d \geq 2)$, an assumption which is not very restrictive, and which has a natural physical interpretation, is that the corresponding Kraus operators form a representation of a Lie algebra. Physically, this is a symmetry algebra for the interaction Hamiltonian. This paper begins a systematic study of channels defined by representations; the famous Werner-Holevo channel is one element of this infinite class. We show that the channel derived from the defining representation of SU(n) is a depolarizing channel for all $n$, but for most other representations this is not the case. Since the Bloch sphere is not appropriate here, we develop technology which is a generalization of Bloch's technique. Our method works by representing the density matrix as a polynomial in symmetrized products of Lie algebra generators, with coefficients that are symmetric tensors. Using these tensor methods we prove eleven theorems, derive many explicit formulas and show other interesting properties of quantum channels in various dimensions, with various Lie symmetry algebras. We also derive numerical estimates on the size of a generalized ``Bloch sphere'' for certain channels. There remain many open questions which are indicated at various points through the paper.Comment: 28 pages, 1 figur

High Order QED Corrections in Physics of Positronium

High-order perturbative corrections to positronium decays and hyperfine splitting are briefly reviewed. Theoretical predictions are compared to the most recent experimental data. Perspectives of future calculations are discussed.Comment: 8 pages, LaTeX, talk given at Workshop on Positronium Physics, ETH Honggerberg, Zurich, May 30-31, 2003, a misprint in Eq. (1) correcte