Regrowth-related defect formation and evolution in 1 MeV amorphized (001) Ge

Geimplanted with 1MeV Si⁺ at a dose of 1×10¹⁵cm⁻² creates a buried amorphous layer that, upon regrowth, exhibits several forms of defects–end-of-range (EOR), regrowth-related, and clamshell defects. Unlike Si, no planar {311} defects are observed. The minimal EOR defects are small dotlike defects and are very unstable, dissolving between 450 and 550°C. This is in contrast to Si, where the EOR defects are very stable. The amorphous layer results in both regrowth-related defects and clamshell defects, which were more stable than the EOR damage.This work is supported by Semiconductor Research Corporation Contract No. 00057787

Shifting the paradigm on cultural property and heritage in international law and armed conflict: time to talk about reparations?

The demolition of the mausoleums in Timbuktu, the destruction of the Temple of Bel in Palmyra, and the aerial bombardment of the Old City of Sana’a in Yemen - each mark a continuing trend of intentionally targeting cultural property, and disregard for its protection under international humanitarian law. From as far back as records of war exist, through to contemporary conflicts, cultural sites have been a target for states and non-state armed groups. The destruction is used as a means to delegitimise opponents and displace their populations, reject the symbols of a regime, disrupt a sense of continuity for communities and corrode collective identities. (Brosché et al. 2017 & Ascherson 2005) While international law has focused on a three-P approach (hereafter ‘PPP’), imposing obligations on states to preserve, protect and prosecute the destruction of cultural property, treaties in this area remain silent on the aftermaths of such violence with little attention to reconstruction or reparative measures, thus further endangering sites. Moreover, such treaties emphasise the physical and properterial manifestations of heritage, neglecting its more intangible manifestations that are equally destroyed – such as language and traditions, oral history, songs and dance. As a result there is a vast lacuna in addressing the real impact of war on communities whose cultural heritage, and through it the cultural bonds between individuals and across generations, is destroyed.AHR

The University of Pittsburgh: a three and three-quarter-year experience with cadaveric renal transplantation under the point system.

Eight hundred and sixty kidney transplants were performed at the University of Pittsburgh over a 3.75-year period between January 1, 1986 and October 19, 1989. Recipient selection was by means of a computerized point system designed to allocate organs equitably. Ninety-three percent 1-year patient survival and 74% 1-year graft survival were obtained in the overall group; 80% 1-year graft survival was obtained in patients receiving immunosuppression with CsA, azathioprine, and prednisone. These data serve as a measure of what can be achieved with an equitably based allocation system and can serve as a basis of comparison with other allocation protocols or new immunosuppressive regimens

Projected Effects of Trade Liberalization on U.S. Specialty Crops

This study analyzes the effects of liberalization barriers to trade for six U.S. specialty crops: fresh grapes, fresh oranges, fresh grapefruits, peanuts, potatoes and almonds. The total value of Unites States exports of each commodity to the world and to the major four or five importers is given in Table A. The corresponding market share of U.S. export values are also presented. The major trade barriers considered in calculating the effects of trade liberalization for each of these major importers of U.S. specialty crops are summarized in Table B. To provide an overview of recent market developments in each commodity sector, we calculate the quantity and market share of exports by the United States to each major importer in Table 1 (there is a \u27Table 1\u27 for each commodity organized in section entitled Tables and Charts ). Table 1 also gives the world total trade volumes ( world refers to total U.S. exports). For example, the final column of Table 1 gives U.S. market share of total world trade for that commodity. The data for 1980-1990 are actual data and the years 1991-2000 are projected from trend using 1980-1990 data

Calibration of the Ames Anechoic Facility. Phase 1: Short range plan

A calibration was made of the acoustic and aerodynamic characteristics of a small, open-jet wind tunnel in an anechoic room. The jet nozzle was 102 mm diameter and was operated subsonically. The anechoic-room dimensions were 7.6 m by 5.5 m by 3.4 m high (wedge tip to wedge tip). Noise contours in the chamber were determined by various jet speeds and exhaust collector positions. The optimum nozzle/collector separation from an acoustic standpoint was 2.1 m. Jet velocity profiles and turbulence levels were measured using pressure probes and hot wires. The jet was found to be symmetric, with no unusual characteristics. The turbulence measurements were hampered by oil mist contamination of the airflow

Exchange anisotropy pinning of a standing spin wave mode

Standing spin waves in a thin film are used as sensitive probes of interface pinning induced by an antiferromagnet through exchange anisotropy. Using coplanar waveguide ferromagnetic resonance, pinning of the lowest energy spin wave thickness mode in Ni(80)Fe(20)/Ir(25)Mn(75) exchange biased bilayers was studied for a range of IrMn thicknesses. We show that pinning of the standing mode can be used to amplify, relative to the fundamental resonance, frequency shifts associated with exchange bias. The shifts provide a unique `fingerprint' of the exchange bias and can be interpreted in terms of an effective ferromagnetic film thickness and ferromagnet/antiferromagnet interface anisotropy. Thermal effects are studied for ultra-thin antiferromagnetic Ir(25)Mn(75) thicknesses, and the onset of bias is correlated with changes in the pinning fields. The pinning strength magnitude is found to grow with cooling of the sample, while the effective ferromagnetic film thickness simultaneously decreases. These results suggest that exchange bias involves some deformation of magnetic order in the interface region.Comment: 7 pages, 7 figure

The Vector Vortex Coronagraph: Laboratory Results and First Light at Palomar Observatory

High-contrast coronagraphy will be needed to image and characterize faint extra-solar planetary systems. Coronagraphy is a rapidly evolving field, and many enhanced alternatives to the classical Lyot coronagraph have been proposed in the past ten years. Here, we discuss the operation of the vector vortex coronagraph, which is one of the most efficient possible coronagraphs. We first present recent laboratory results, and then first light observations at the Palomar observatory. Our near-infrared H-band (centered at ~ 1.65 microns) and K-band (centered at ~ 2.2 microns) vector vortex devices demonstrated excellent contrast results in the lab, down to ~ 1e-6 at an angular separation of 3 lb/d. On sky, we detected a brown dwarf companion 3000 times fainter than its host star (HR 7672) in the Ks band (centered at ~2.15 microns), at an angular separation of ~ 2.5 lb/d. Current and next-generation high-contrast instruments can directly benefit from the demonstrated capabilities of such a vector vortex: simplicity, small inner working angle, high optical throughput (>90%), and maximal off-axis discovery space

Identifying volcanic signals in Irish temperature observations since AD 1800

Large volcanic eruptions have been shown to affect temperature patterns to varying degrees on continental, hemispheric or global scales. However, few studies have systematically explored the influence of volcanic eruptions on temperatures at a local, Irish level. The focus of this paper is to determine the impacts of five high-magnitude low-latitude volcanic eruptions and one such Icelandic event on Irish climate over the past 200 years. Daily temperature data from the Armagh Observatory, Co. Armagh, Northern Ireland was used to assess the influence of volcanic eruptions on seasonal and yearly values through time. The paper explores volcanically-induced temperature trends by filtering out the influence of the North Atlantic Oscillation (NAO) and solar variability, and goes on to employ a variation of Superposed Epoch Analysis to identify which seasons and years are most significantly affected by large volcanic eruptions. Armagh temperatures proved particularly responsive in the spring, with a significant decrease in values in the four years following an eruption. Winter temperatures also exhibited a volcanic influence, with a small initial increase in the year of and year following an eruption, and a significant decrease in residual temperature in years two and three after the event