Quantitative LEED I-V and ab initio study of the Si(111)-3x2-Sm surface structure and the missing half order spots in the 3x1 diffraction pattern

We have used Low Energy Electron Diffraction (LEED) I-V analysis and ab initio calculations to quantitatively determine the honeycomb chain model structure for the Si(111)-3x2-Sm surface. This structure and a similar 3x1 recontruction have been observed for many Alkali-Earth and Rare-Earth metals on the Si(111) surface. Our ab initio calculations show that there are two almost degenerate sites for the Sm atom in the unit cell and the LEED I-V analysis reveals that an admixture of the two in a ratio that slightly favours the site with the lower energy is the best match to experiment. We show that the I-V curves are insensitive to the presence of the Sm atom and that this results in a very low intensity for the half order spots which might explain the appearance of a 3x1 LEED pattern produced by all of the structures with a 3x2 unit cell.Comment: 10 pages, 13 figures. Preliminary work presented at the the APS March meeting, Baltimore MD, 2006. To be published in Phys. Rev. B. April/May 200

Structurally Embedded Electrical Systems Using Ultrasonic Consolidation (UC)

Current research has demonstrated the use of Ultrasonic Consolidation (UC) to embed several USB-based sensors into aluminum, and is working toward embedding suites of sensors, heaters and other devices, connected via USB hubs, which can be monitored and controlled using an embedded USB capable processor. Additionally, the research has shown that electronics can be embedded at room temperature, but with some inter-layer delamination between the ultrasonically bonded aluminum layers. Embedding sensors and electronics at 300o F to overcome the delamination issues resulted in optimal bonding, and the sensors used thus far have functioned normally. Future investigation will explore other UC parameter combinations to ascertain the quality of embedding at lower temperatures.Mechanical Engineerin

Changing tides: Online conspiracy theory use by radical violent extremist groups over time

Radical violent extremist terrorism is a global issue that has existed for centuries and has been the cause of millions of deaths. Extremist organizations have learned to adapt and survive attempts at legal/military interdictions. One possible major element that allows for the survival of these radicalized organizations is the use of conspiracy theories within their online messages that are used to radicalize and recruit members to their cause. These conspiracy theories tend to elicit two types of messages: a quest for significance or a loss of significance. This study aims to observe how extremist organizations utilize conspiracy theories in their online messages to adapt to the standing of the organization (growth, height, and decline). This study will utilize a 2x3 non-experimental, correlational content analysis of historical documents using text-based algorithms via latent dirichlet allocation to examine the frequency of conspiracy theory usage (presence or absence) from radical Islamic (ISIS) and right-wing extremist groups (QAnon) used over time. There was no significant pattern between conspiracy theory usage and ISIS’s timeframe standing, X2(2) = 0.90, p = .32. The data from the QAnon Drops showed too many discrepancies among the post frequencies across different time frames so supplemental analyses were run to examine change in conspiracy theory use between the growth and height time frames as well as change in conspiracy theory theme over time. There was a significant pattern between conspiracy theory use and timeframe, X2(1)=10.95, p\u3c.001. The themes of conspiracy theories appear to change over time, which may be attributed to historic events at the time. Future studies should aim to even the post frequencies and continue to expand upon this research to grasp the methodology of extremist organizations and their usage of conspiracy theories

The Valuation Of Special Items

This research examines the value relevance of GAAP earnings, GAAP earnings excluding special items, and specific special items.  We find GAAP earnings to be less value relevant than GAAP earnings adjusted to exclude special items.  We find mixed results relating to the value relevance of net special items. Considering the value relevance of eight specific categories of special items, only two, in process research and development and merger related costs, appear to be significantly related to firm value.  This suggests that analysts distinguish between types of special items and only specific types of special items contribute to firm value

STM and ab initio study of holmium nanowires on a Ge(111) Surface

A nanorod structure has been observed on the Ho/Ge(111) surface using scanning tunneling microscopy (STM). The rods do not require patterning of the surface or defects such as step edges in order to grow as is the case for nanorods on Si(111). At low holmium coverage the nanorods exist as isolated nanostructures while at high coverage they form a periodic 5x1 structure. We propose a structural model for the 5x1 unit cell and show using an ab initio calculation that the STM profile of our model structure compares favorably to that obtained experimentally for both filled and empty states sampling. The calculated local density of states shows that the nanorod is metallic in character.Comment: 4 pages, 12 figures (inc. subfigures). Presented at the the APS March meeting, Baltimore MD, 200

Arrival direction distribution of cosmic rays of energy 10 (18) eV

The Haverah Park air-shower experiment recorded over 8500 events with primary energy 10 to the 18th power eV between 1963 and 1983. An analysis of these events for anisotropies in celestial and galactic coordinates is reported. No very striking anisotropies are observed

A motif-based approach to network epidemics

Networks have become an indispensable tool in modelling infectious diseases, with the structure of epidemiologically relevant contacts known to affect both the dynamics of the infection process and the efficacy of intervention strategies. One of the key reasons for this is the presence of clustering in contact networks, which is typically analysed in terms of prevalence of triangles in the network. We present a more general approach, based on the prevalence of different four-motifs, in the context of ODE approximations to network dynamics. This is shown to outperform existing models for a range of small world networks

A comparison of structural and behavioural adaptations to future proofing buildings against higher temperatures

Copyright © 2012 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Building and Environment . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Building and Environment Vol. 55 (2012), DOI: 10.1016/j.buildenv.2011.12.011The uncertainty surrounding projections of climate change has left the building design community in a quandary. Should they assume a worst case scenario, and recommend adaptations to designs that might prove to be unnecessary and quite possibly costly? Or should they increase the risk to the occupants by selecting a less pessimistic vision of the future? It is well known that structural adaptations, such as additional thermal mass, can help moderate internal conditions as can behavioural adaptations, such as opening windows. Here the relative magnitudes of structural and non-structural (behavioural) adaptations are reflected upon, with the specific intent of discovering whether non-structural adaptations might have a great enough effect to offset any errors from selecting what proves to be (in 40 years time) an erroneous choice of climate change projection. It is found that an alteration to how a building is used is as equally important as common structural adaptations, and that the risk of choosing what turns out to be an incorrect climate change projection can be dealt with by seeing non-structural adaptations as a way of nullifying this risk