Investigation of the nonlocal coherent-potential approximation

Recently the nonlocal coherent-potential approximation (NLCPA) has been introduced by Jarrell and Krishnamurthy for describing the electronic structure of substitutionally disordered systems. The NLCPA provides systematic corrections to the widely used coherent-potential approximation (CPA) whilst preserving the full symmetry of the underlying lattice. Here an analytical and systematic numerical study of the NLCPA is presented for a one-dimensional tight-binding model Hamiltonian, and comparisons with the embedded cluster method (ECM) and molecular coherent potential approximation (MCPA) are made.Comment: 18 pages, 5 figure

Butt Joint Reinforcement in Parallel-Laminated Veneer (PLV) Lumber

Parallel-laminated veneer (PLV) is a high-strength structural material consisting of thin parallel-laminated wood veneers. The use of graphite-cloth reinforcement, placed on either side of a butt joint in 1 1/2- by 3 1/2- by 32-inch Douglas-fir PLV tensile members, was assessed. The finite-element method of analysis was used to predict the behavior in different unreinforced and reinforced butt-jointed PLV tensile members. Relationships between the reinforcing parameters—length, modulus of elasticity, and thickness—and the stresses in the wood and reinforcement components were developed by regression analysis techniques. The reinforcing mechanism reduced the peak stresses at the butt joint and hence increased the ultimate strength of the member. Design of PLV material whose strength is limited by shear stresses that develop at the butt joint is facilitated by use of the proposed relationships.Experimental testing confirmed the predictions of the finite-element analysis. Failure initiated at the unreinforced joint in the specimens. Average tensile strength increased and variability decreased in reinforced specimens. Application of a small amount of reinforcement at the butt joint has been shown to enhance PLV performance

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

Recently CMOS Active Pixels Sensors (APSs) have become a valuable alternative to amorphous Silicon and Selenium Flat Panel Imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ≤ 1.9%. The uniformity of the image quality performance has been further investigated in a typical X-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practise. Finally, in order to compare the detection capability of this novel APS with the currently used technology (i.e. FPIs), theoretical evaluation of the Detection Quantum Efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this detector compared to FPIs. Optical characterization, X-ray contrast measurements and theoretical DQE evaluation suggest that a trade off can be found between the need of a large imaging area and the requirement of a uniform imaging performance, making the DynAMITe large area CMOS APS suitable for a range of bio-medical applications

Low prevalence of Epstein–Barr virus in incident gastric adenocarcinomas from the United Kingdom

Epstein–Barr virus has been associated with a proportion of typical gastric adenocarcinomas. Here we report that the prevalence of Epstein–Barr virus in gastric adenocarcinomas from the United Kingdom is one of the lowest in the World. Gastric adenocarcinoma is another tumour whose association with Epstein–Barr virus varies with the population studied

Factors influencing publication choice: why faculty choose open access

BACKGROUND: In an attempt to identify motivating factors involved in decisions to publish in open access and open archives (OA) journals, individual interviews with biomedical faculty members at the University of North Carolina at Chapel Hill (UNC-Chapel Hill) and Duke University, two major research universities, were conducted. The interviews focused on faculty identified as early adopters of OA/free full-text publishing. METHODS: Searches conducted in PubMed and PubMed Central identified faculty from the two institutions who have published works in OA/free full-text journals. The searches targeted authors with multiple OA citations during a specified 18 month period. Semi-structured interviews were conducted with the most prolific OA authors at each university. Individual interviews attempted to determine whether the authors were aware they published in OA journals, why they chose to publish in OA journals, what factors influenced their publishing decisions, and their general attitude towards OA publishing models. RESULTS & DISCUSSION: Fourteen interviews were granted and completed. Respondents included a fairly even mix of Assistant, Associate and Full professors. Results indicate that when targeting biomedical faculty at UNC-Chapel Hill and Duke, speed of publication and copyright retention are unlikely motivating factors or incentives for the promotion of OA publishing. In addition, author fees required by some open access journals are unlikely barriers or disincentives. CONCLUSION: It appears that publication quality is of utmost importance when choosing publication venues in general, while free access and visibility are specifically noted incentives for selection of OA journals. Therefore, free public availability and increased exposure may not be strong enough incentives for authors to choose open access over more traditional and respected subscription based publications, unless the quality issue is also addressed

The narrative self, distributed memory, and evocative objects

In this article, I outline various ways in which artifacts are interwoven with autobiographical memory systems and conceptualize what this implies for the self. I first sketch the narrative approach to the self, arguing that who we are as persons is essentially our (unfolding) life story, which, in turn, determines our present beliefs and desires, but also directs our future goals and actions. I then argue that our autobiographical memory is partly anchored in our embodied interactions with an ecology of artifacts in our environment. Lifelogs, photos, videos, journals, diaries, souvenirs, jewelry, books, works of art, and many other meaningful objects trigger and sometimes constitute emotionally-laden autobiographical memories. Autobiographical memory is thus distributed across embodied agents and various environmental structures. To defend this claim, I draw on and integrate distributed cognition theory and empirical research in human-technology interaction. Based on this, I conclude that the self is neither defined by psychological states realized by the brain nor by biological states realized by the organism, but should be seen as a distributed and relational construct

Вплив екологічного стану Донецького регіону на його демографічний розвиток

В статті розглянуто важливу проблему впливу забрудненості навколишнього природного середовища на захворюваність та смертність в регіоні. Визначено кореляційну залежність між обсягом викидів забруднюючих речовин та окремими видами захворюваності, а також ступінь їх впливу, побудовано функції, що описують їх.В статье рассмотрена важная проблема влияния загрязненности окружающей естественной среды на заболеваемость и смертность в регионе. Определена корреляционная зависимость между объемом выбросов загрязняющих веществ и отдельными видами заболеваемости, а также степень их влияния, построены функции, которые описывают их.In the article the important problem of influence of muddiness of natural environment is considered on morbidity and death rate in a region. Certainly cross-correlation dependence between the volume of extrass of contaminents and separate types of morbidity, and also degree of their influence, functions which describe them are built. Keywords: environment