Contributions to the mixed-alkali effect in molecular dynamics simulations of alkali silicate glasses

The mixed-alkali effect on the cation dynamics in silicate glasses is analyzed via molecular dynamics simulations. Observations suggest a description of the dynamics in terms of stable sites mostly specific to one ionic species. As main contributions to the mixed--alkali slowdown longer residence times and an increased probability of correlated backjumps are identified. The slowdown is related to the limited accessibility of foreign sites. The mismatch experienced in a foreign site is stronger and more retarding for the larger ions, the smaller ions can be temporarily accommodated. Also correlations between unlike as well as like cations are demonstrated that support cooperative behavior.Comment: 10 pages, 12 figures, 1 table, revtex4, submitted to Phys. Rev.

Propagating mass accretion rate fluctuations in X-ray binaries under the influence of viscous diffusion

Many statistical properties of X-ray aperiodic variability from accreting compact objects can be explained by the propagating fluctuations model applied to the accretion disc. The mass accretion rate fluctuations originate from variability of viscosity, which arises at every radius and causes local fluctuations of the density. The fluctuations diffuse through the disc and result in local variability of the mass accretion rate, which modulates the X-ray flux from the inner disc in the case of black holes, or from the surface in the case of neutron stars. A key role in the theoretical explanation of fast variability belongs to the description of the diffusion process. The propagation and evolution of the fluctuations is described by the diffusion equation, which can be solved by the method of Green functions. We implement Green functions in order to accurately describe the propagation of fluctuations in the disc. For the first time we consider both forward and backward propagation. We show that (i) viscous diffusion efficiently suppress variability at time scales shorter than the viscous time, (ii) local fluctuations of viscosity affect the mass accretion rate variability both in the inner and the outer parts of accretion disc, (iii) propagating fluctuations give rise not only to hard time lags as previously shown, but also produce soft lags at high frequency similar to those routinely attributed to reprocessing, (iv) deviation from the linear rms-flux relation is predicted for the case of very large initial perturbations. Our model naturally predicts bumpy power spectra.Comment: 20 pages, 17 figures, accepted for publication in MNRA

London SynEx Demonstrator Site: Impact Assessment Report

The key ingredients of the SynEx-UCL software components are: 1. A comprehensive and federated electronic healthcare record that can be used to reference or to store all of the necessary healthcare information acquired from a diverse range of clinical databases and patient-held devices. 2. A directory service component to provide a core persons demographic database to search for and authenticate staff users of the system and to anchor patient identification and connection to their federated healthcare record. 3. A clinical record schema management tool (Object Dictionary Client) that enables clinicians or engineers to define and export the data sets mapping to individual feeder systems. 4. An expansible set of clinical management algorithms that provide prompts to the patient or clinician to assist in the management of patient care. CHIME has built up over a decade of experience within Europe on the requirements and information models that are needed to underpin comprehensive multiprofessional electronic healthcare records. The resulting architecture models have influenced new European standards in this area, and CHIME has designed and built prototype EHCR components based on these models. The demonstrator systems described here utilise a directory service and object-oriented engineering approach, and support the secure, mobile and distributed access to federated healthcare records via web-based services. The design and implementation of these software components has been founded on a thorough analysis of the clinical, technical and ethico-legal requirements for comprehensive EHCR systems, published through previous project deliverables and in future planned papers. The clinical demonstrator site described in this report has provided the solid basis from which to establish "proof of concept" verification of the design approach, and a valuable opportunity to install, test and evaluate the results of the component engineering undertaken during the EC funded project. Inevitably, a number of practical implementation and deployment obstacles have been overcome through this journey, each of those having contributed to the time taken to deliver the components but also to the richness of the end products. UCL is fortunate that the Whittington Hospital, and the department of cardiovascular medicine in particular, is committed to a long-term vision built around this work. That vision, outlined within this report, is shared by the Camden and Islington Health Authority and by many other purchaser and provider organisations in the area, and by a number of industrial parties. They are collectively determined to support the Demonstrator Site as an ongoing project well beyond the life of the EC SynEx Project. This report, although a final report as far as the EC project is concerned, is really a description of the first phase in establishing a centre of healthcare excellence. New EC Fifth Framework project funding has already been approved to enable new and innovative technology solutions to be added to the work already established in north London

Design and implementation of a federated health record server

This paper describes the practical implementation of a federated health record serverbased on a generic and comprehensive public domain architecture and deployed in alive clinical setting.The authors, working at the Centre for Health Informatics and MultiprofessionalEducation (University College London), have built up over a decade of experiencewithin Europe on the requirements and information models that are needed to underpincomprehensive multi-professional electronic health records. This work has involvedcollaboration with a wide range of healthcare and informatics organisations and partnersin the healthcare computing industry across Europe though the EU Health Telematicsprojects GEHR, Synapses, EHCR-SupA, SynEx and Medicate. The resultingarchitecture models have influenced recent European standards in this area, such asCEN TC/251 ENV 13606. UCL has now designed and built a federated health recordserver based on these models which is now running in the Department ofCardiovascular Medicine at the Whittington Hospital in north London. A new EC FifthFramework project, 6WINIT, is enabling new and innovative IPv6 and wirelesstechnology solutions to be added to this work.The north London clinical demonstrator site has provided the solid basis from which toestablish "proof of concept" verification of the design approach, and a valuableopportunity to install, test and evaluate the results of the component engineeringundertaken during the EC funded projects

Definition of smolder experiments for Spacelab

The feasibility of conducting experiments in space on smoldering combustion was studied to conceptually design specific smoldering experiments to be conducted in the Shuttle/Spacelab System. Design information for identified experiment critical components is provided. The analytical and experimental basis for conducting research on smoldering phenomena in space was established. Physical descriptions of the various competing processes pertaining to smoldering combustion were identified. The need for space research was defined based on limitations of existing knowledge and limitations of ground-based reduced-gravity experimental facilities

Beat Generation's Impact on Neal Cassady

The Beat Generation is one of the most influential movements in American literature. The lives of these writers are just as fascinating as their stories and poetry. The most important members and contributors were writer Jack Kerouac, poet Allen Ginsberg, and their best friend, lover, and muse Neal Cassady. These three men, as well as others along the way, would redefine the roles of men in a post-World War II America as well as create a new image for the country. Arguably, it was Cassady who was the catalyst for this movement, but he hardly wrote a word. He came to New York from Denver, where his past was fabricated and unbelievable, to have Kerouac teach him how to write. Cassady, the conman, wanted to learn from Kerouac and then from Ginsberg. He was immortalized in Jack Kerouac’s On the Road as Dean Moriarty, the rebel from Denver, who always chose adventure over responsibility. Allen Ginsberg wrote him as a “secret hero” in his most famous poem “Howl” (Ginsberg 136). Both Kerouac and Ginsberg idolized Cassady but for different reasons. Cassady himself is an enigma, his entire life story a fabrication. He grew up on the streets of Denver, stealing cars and hustling. He was also an altar boy and a father of three, and even tried his hand at writing with his unfinished autobiography The First Third. With the help of Kerouac, he managed to make his life into what would later be the embodiment of the Beat Generation. Kerouac made him seem far more adventurous than Cassady perhaps really wanted to be. Ginsberg, on the other hand, drew upon Cassady’s sex life in his poetry, focusing on Cassady as a sex symbol. Both interpretations took a heavy toll on Cassady as he attempted to keep up with the demands of those who had read On the Road and “Howl.” For the rest of his life he would try to uphold the standards imposed on him by his friends and the youth of generations to come. The impact of Kerouac, Ginsberg, and Cassady can be seen in every aspect of the writers’ lives. The standards they set for Cassady became the standards they themselves had to live up to and die by