Energy Dependent Contrast in Atomic-Scale Spin-Polarized Scanning Tunneling Microscopy ofMn3N2(010): Experiment and First-Principles Theory

The technique of spin-polarized scanning tunneling microscopy is investigated for its use in determining fine details of surface magnetic structure down to the atomic scale. As a model sample, the row-wise anti-ferromagnetic Mn3N2(010) surface is studied. It is shown that the magnetic contrast in atomic-scale images is a strong function of the bias voltage around the Fermi level. Inversion of the magnetic contrast is also demonstrated. The experimental SP-STM images and height profiles are compared with simulated SP-STM images and height profiles based on spin-polarized density functional theory. The success of different tip models in reproducing the non-magnetic and magnetic STM data is explored.Comment: 15 pages, 7 figure

Exocentric direction judgements in computer-generated displays and actual scenes

One of the most remarkable perceptual properties of common experience is that the perceived shapes of known objects are constant despite movements about them which transform their projections on the retina. This perceptual ability is one aspect of shape constancy (Thouless, 1931; Metzger, 1953; Borresen and Lichte, 1962). It requires that the viewer be able to sense and discount his or her relative position and orientation with respect to a viewed object. This discounting of relative position may be derived directly from the ranging information provided from stereopsis, from motion parallax, from vestibularly sensed rotation and translation, or from corollary information associated with voluntary movement. It is argued that: (1) errors in exocentric judgements of the azimuth of a target generated on an electronic perspective display are not viewpoint-independent, but are influenced by the specific geometry of their perspective projection; (2) elimination of binocular conflict by replacing electronic displays with actual scenes eliminates a previously reported equidistance tendency in azimuth error, but the viewpoint dependence remains; (3) the pattern of exocentrically judged azimuth error in real scenes viewed with a viewing direction depressed 22 deg and rotated + or - 22 deg with respect to a reference direction could not be explained by overestimation of the depression angle, i.e., a slant overestimation

Medical Command and Control in Sea-Based Operations

During World War II it took the Navy and Marine Corps years to confirm and refine their prewar doctrine for amphibious attack. The labor began with the first U.S. landings at Guadalcanal in August 1942; the resulting doc- trine, organization, tactics, and techniques were subsequently used by the Army in Europe. Early operations in both theaters highlighted the enormous difficul- ties associated with essential medical elements, and it was not until late 1944, perhaps 1945, that these problems were adequately solved

The Discrimination of Religious Minorities in the United States

The following issue brief is meant to address discrimination that minority religions deal with in the United States. This includes inhibiting their rights to practice, their rights to build places of worship, and be accepted amongst the community of all religious organizations

Manganese 3×3 and √3 × √3-R30º structures and structural phase transition on w-GaN(0001̄) studied by scanning tunneling microscopy and first-principles theory

et al.Manganese deposited on the N-polar face of wurtzite gallium nitride [GaN (0001̄)] results in two unique surface reconstructions, depending on the deposition temperature. At lower temperature (less than 105ºC), it is found that a metastable 3×3 structure forms. Mild annealing of this Mn 3×3 structure leads to an irreversible phase transition to a different, much more stable √3×√3-R30º structure which can withstand high-temperature annealing. Scanning tunneling microscopy (STM) and reflection high-energy electron diffraction data are compared with results from first-principles theoretical calculations. Theory finds a lowest-energy model for the 3×3 structure consisting of Mn trimers bonded to the Ga adlayer atoms but not with N atoms. The lowest-energy model for the more stable √3×√3-R30º structure involves Mn atoms substituting for Ga within the Ga adlayer and thus bonding with N atoms. Tersoff-Hamman simulations of the resulting lowest-energy structural models are found to be in very good agreement with the experimental STM images.Research supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. DE-FG02-06ER46317 (STM studies of nanoscale spintronic nitride systems) and by the National Science Foundation under Award No. 0730257 (advancing nanospintronics through international collaboration). V.F. and M.A.B. would like to acknowledge support from CONICET (PIP0038) and ANPCyT (PICT1857) as well as the Ohio Supercomputing Center for computer time. P.O. was supported by Spanish MICINN (FIS2009-12721-C04-01, FIS2012-37549-C05-02 and CSD2007-00050).Peer reviewe

Exploring the Policy Implications of the Surface Mining Control and Reclamation Act

This paper explores how policy structure, institutions, and political climate impact the ability of the Surface Mining Control and Reclamation Act (SMCRA) to ensure the reclamation of surface coal mines. We conduct a policy review that traces the impacts of the three parts of SMCRA; Reclamation Standards, Reclamation Bonding Requirements, and the Abandoned Mine Land fund. We examine the implications the act and its approach have for the mining industry and their ability to reclaim mining areas. We find that each of the three parts of SMCRA’s approach face substantial problems in their implementation. Though largely a positive force for internalizing the environmental costs of surface mining, those issues commonly elucidated in the public choice literature reduce the efficacy of the policy approach and call into question the act’s ability to ensure reclamation occurs. Both in the structure of the bonding requirements and in the regulatory structure created by the act, misaligned incentives sometimes hamper effective reclamation. Further, the funds created under SMCRA to reclaim and restore mined lands have often been directed towards projects that are politically expedient for politicians instead of those that would best serve the fund’s original reclamation purpose. After revealing these problems and putting them in the context of the public choice literature, we suggest updates to the current policy that would align reclamation incentives and better ensure that the reclamation of surface mines occurs. We emphasize the cooperative elements of SMCRA and suggest how other countries, especially those without major existing frameworks for handling reclamation, can emulate the successes of SMCRA while avoiding its implementations snags

A Techniques Manual And Video For The Management Of Problem Urban Canada Geese

Social and management problems associated with urban Canada geese (Branta canadensis) are increasing in area, scope and magnitude. Although there are many articles on the management of urban Canada geese, none provide enough information for a reader to understand the impact geese have on different people, the ecology of the urban goose, evaluate the effectiveness of potential control options, choose appropriate management techniques, and then implement the chosen techniques. The authors present a manual and video, which in combination, they believe are not deficient in any of these areas. The video is intended to increase the awareness and knowledge of human/goose conflicts in urban and suburban environments. The manual covers the biology of Canada geese relevant to problem management in an urban setting and a comprehensive list of management techniques. Detailed instructions for implementation, permit requirements, sources of equipment and supplies, and a discussion of advantages, disadvantages, and characteristics, are included for each technique. To assist in choosing and locating appropriate techniques, quick reference summary tables are included

Building a Quality of Life Index

This chapter outlines how an index measuring quality of life should be developed and then applies that work at the county level in the United States. The index we create is a unique and data‐driven approach to calculating quality of life. In the chapter, we explain the process that leads us to selecting our five indicators: public safety, health, economic development, infrastructure, and education. Each indicator breaks apart into subindicators. This chapter theoretically and statistically verifies our chosen indicators. First, we develop theoretical arguments explaining the connections between quality of life and our indicators. Then, we perform confirmatory factor analyses on our index to empirically verify our theoretical arguments for why each component should be included in the index. Further, we finally verify our theory and index using survey results. We use only publicly available data to facilitate replication by others. The results of our confirmatory factor analysis provide statistical evidence for our choice of indicators in measuring quality of life. Our findings indicate that those measuring quality of life must account for the roles of: public safety, health, economic development, infrastructure, and education. Most importantly, our results indicate that our index is a valid measure of quality of life