An ant-inspired, deniable routing approach in ad hoc question & answer networks

The ubiquity of the Internet facilitates electronic question and answering (Q&A) between real people with ease via community portals and social networking websites. It is a useful service which allows users to appeal to a broad range of answerers. In most cases however, Q&A services produce answers by presenting questions to the general public or associated digital community with little regard for the amount of time users spend examining and answering them. Ultimately, a question may receive large amounts of attention but still not be answered adequately. Several existing pieces of research investigate the reasons why questions do not receive answers on Q&A services and suggest that it may be associated with users being afraid of expressing themselves. Q&A works well for solving information needs, however, it rarely takes into account the privacy requirements of the users who form the service. This thesis was motivated by the need for a more targeted approach towards Q&A by distributing the service across ad hoc networks. The main contribution of this thesis is a novel routing technique and networking environment (distributed Q&A) which balances answer quality and user attention while protecting privacy through plausible deniability. Routing approaches are evaluated experimentally by statistics gained from peer-to-peer network simulations, composed of Q&A users modelled via features extracted from the analysis of a large Yahoo! Answers dataset. Suggestions for future directions to this work are presented from the knowledge gained from our results and conclusion

Gluinos condensing at the CCNI: 4096 CPUs weigh in

We report preliminary results of lattice super-Yang-Mills computations using domain wall fermions, performed at an actual rate of 1000 Gflop/s, over the course of six months, using two BlueGene/L racks at Rensselaer's CCNI supercomputing center. This has allowed us to compute the gluino condensate and string tension over a wide range of lattice parameters, setting the stage for continuum, chiral extrapolations.Comment: 9 pages, 3 figures, talk given at "Continuous Advances in QCD 2008," Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN, May 15-18, 2008; v2: reference adde

A Century of Music Production in Durham City 1711-1811: A Documentary Study.

In the eighteenth century, Durham City was an important centre of political power, the nucleus of which was the cathedral whose own wealth and power was immense. The Bishop, as the King’s representative, governed County Durham, and Durham City, as the capital of the palatinate, was a vibrant socio-economic centre. Those with means spent much of their free time patronising the large number of concerts, balls, assemblies, or theatrical productions that were frequently held in the city. For a musician, these public events provided ample opportunities to make a living. There were also opportunities to teach the children of wealthy patrons and to publish compositions. In consequence a large number of musicians came to the city, either to live or to visit, with race and assize weeks (the busiest time of the year) as a major focus of their employment. The centre of musical life in Durham was the cathedral which dominated the production of both sacred and secular music. In order to attract good quality singers to the north, the cathedral’s Chapter offered unusually high salaries to its lay-clerks. The clerks, as able singers, forged a high reputation as a musical force in the region at a time when the quality of sacred music and cathedral choirs was in serious decline. Some of the lay-clerks, most notably Edward Meredith and William Evance, would travel large distances to perform. Until 1763 the cathedral organist was James Hesletine who was succeeded by Thomas Ebdon. Both men were also involved in the local concert scene, although, under Hesletine, a significant dispute with the Newcastle musician Charles Avison took place which ultimately led to the establishment of a rival subscription series by Avison in partnership with John Garth. Music permeated all levels of society at Durham. In addition to what was produced for concerts and at the cathedral, music was prevalent in many other arenas. Music formed part of worship in all of the city’s churches, although it was only at St. Mary le Bow that it reached an appreciable standard. As part of the broader matrix of performances of secular music, Durham possessed its own musical society, and, as part of its wider public role, music performed a key role in civic and other ceremonial occasions as well as for local freemasonry, an organisation to which many of Durham’s musicians belonged. Other forms of music-making took place in the domestic environment, but it was also possible to find music performed in the city’s taverns. Furthermore, the performance of folk music and the presence of the town waits and military bands meant that music was commonly heard on the city’s streets. This thesis is based on a detailed study of several primary sources. The most important of these is the local newspapers, but ecclesiastical records, diaries, personal letters, published books on music and local history, and the music itself (both printed and in manuscript), have also been closely examined. By means of this archival work it has been possible to examine the whole spectrum of musical life across the city, a study which amply demonstrates that Durham was one of the most important provincial musical centres outside London. In fact, notwithstanding its provincial location, Durham was by no means insular in its outlook, nor was it entirely backward-looking, as can be seen in the distinctly innovative and inventive work of Garth

Selling (un)real estate with "Shi(势)-nema": manipulation, not persuasion, in China's contemporary cinematic-cities

Investigating what has been called the mise-en-scene of Capitalism's Second Coming in China, this essay explores how cinematic principles have become divorced from the medium of cinema and can be found operating within contemporary Chinese urban spaces in order to increase the efficacy of real estate showroom settings. Specifically, we explore the effects of affectively distributed networks of human, architectural and nonhuman " actors " that appear to be arranged in such a way as to manipulate and impact the thoughts, feelings and actions of potential buyers. To best expose the effectiveness of these modern urban assemblages, we engineer an encounter between the Chinese concept of shi (势) – described by sinologist-philosopher François Julien as the " inherent potentiality at work in configuration " – and that of cinematicty, wherein the cinema and city are recognised as co-determining and mutually enabling site/ sights

The Sleep Condition Indicator: a clinical screening tool to evaluate insomnia disorder

Objective: Describe the development and psychometric validation of a brief scale (the Sleep Condition Indicator (SCI)) to evaluate insomnia disorder in everyday clinical practice.<p></p> Design: The SCI was evaluated across five study samples. Content validity, internal consistency and concurrent validity were investigated.<p></p> Participants: 30 941 individuals (71% female) completed the SCI along with other descriptive demographic and clinical information.<p></p> Setting: Data acquired on dedicated websites.<p></p> Results: The eight-item SCI (concerns about getting to sleep, remaining asleep, sleep quality, daytime personal functioning, daytime performance, duration of sleep problem, nights per week having a sleep problem and extent troubled by poor sleep) had robust internal consistency (α≥0.86) and showed convergent validity with the Pittsburgh Sleep Quality Index and Insomnia Severity Index. A two-item short-form (SCI-02: nights per week having a sleep problem, extent troubled by poor sleep), derived using linear regression modelling, correlated strongly with the SCI total score (r=0.90).<p></p> Conclusions: The SCI has potential as a clinical screening tool for appraising insomnia symptoms against Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria.<p></p&gt

Feasibility of ASD AgriSpec analysis to indicate mineralogy of a potential shale gas reservoir from West Lancashire, UK

Mudrocks rich in organic matter present an attractive exploration target for unconventional gas and oil. The mid-Carboniferous Bowland Shale is considered the principal accumulation of gas-prone shales in the UK. One risk with exploitation of shales is that the rocks may exhibit ductile behaviour and not respond well to hydraulic stimulation programmes. The brittle behaviour of the rock is influenced by mineralogical composition. Approximately 15 m of core from the Bowland Shale, has been used to test the feasibility of using Near Infra-Red (NIR) Spectrometry to characterise the mineralogy of the shale, and compare to analysis using standard XRD techniques

Viscous and Resistive Effects on the MRI with a Net Toroidal Field

Resistivity and viscosity have a significant role in establishing the energy levels in turbulence driven by the magnetorotational instability (MRI) in local astrophysical disk models. This study uses the Athena code to characterize the effects of a constant shear viscosity \nu and Ohmic resistivity \eta in unstratified shearing box simulations with a net toroidal magnetic flux. A previous study of shearing boxes with zero net magnetic field performed with the ZEUS code found that turbulence dies out for values of the magnetic Prandtl number, P_m = \nu/\eta, below P_m \sim 1; for P_m \gtrsim 1, time- and volume-averaged stress levels increase with P_m. We repeat these experiments with Athena and obtain consistent results. Next, the influence of viscosity and resistivity on the toroidal field MRI is investigated both for linear growth and for fully-developed turbulence. In the linear regime, a sufficiently large \nu or \eta can prevent MRI growth; P_m itself has little direct influence on growth from linear perturbations. By applying a range of values for \nu and \eta to an initial state consisting of fully developed turbulence in the presence of a background toroidal field, we investigate their effects in the fully nonlinear system. Here, increased viscosity enhances the turbulence, and the turbulence decays only if the resistivity is above a critical value; turbulence can be sustained even when P_m < 1, in contrast to the zero net field model. While we find preliminary evidence that the stress converges to a small range of values when \nu and \eta become small enough, the influence of dissipation terms on MRI-driven turbulence for relatively large \eta and \nu is significant, independent of field geometry.Comment: Accepted to ApJ; version 2 - minor changes following review; 35 pages (preprint format), 10 figure

Resistivity-driven State Changes in Vertically Stratified Accretion Disks

We investigate the effect of shear viscosity and Ohmic resistivity on the magnetorotational instability (MRI) in vertically stratified accretion disks through a series of local simulations with the Athena code. First, we use a series of unstratified simulations to calibrate physical dissipation as a function of resolution and background field strength; the effect of the magnetic Prandtl number, Pm = viscosity/resistivity, on the turbulence is captured by ~32 grid zones per disk scale height, H. In agreement with previous results, our stratified disk calculations are characterized by a subthermal, predominately toroidal magnetic field that produces MRI-driven turbulence for |z| < 2 H. Above |z| = 2 H, magnetic pressure dominates and the field is buoyantly unstable. Large scale radial and toroidal fields are also generated near the mid-plane and subsequently rise through the disk. The polarity of this mean field switches on a roughly 10 orbit period in a process that is well-modeled by an alpha-omega dynamo. Turbulent stress increases with Pm but with a shallower dependence compared to unstratified simulations. For sufficiently large resistivity, on the order of cs H/1000, where cs is the sound speed, MRI turbulence within 2 H of the mid-plane undergoes periods of resistive decay followed by regrowth. This regrowth is caused by amplification of toroidal field via the dynamo. This process results in large amplitude variability in the stress on 10 to 100 orbital timescales, which may have relevance for partially ionized disks that are observed to have high and low accretion states.Comment: very minor changes, accepted to Ap

Lattice Gauge Theories at the Energy Frontier

This White Paper has been prepared as a planning document for the Division of High Energy Physics of the U. S. Department of Energy. Recent progress in lattice-based studies of physics beyond the standard model is summarized, and major current goals of USQCD research in this area are presented. Challenges and opportunities associated with the recently discovered 126 GeV Higgs-like particle are highlighted. Computational resources needed for reaching important goals are described. The document was finalized on February 11, 2013 with references that are not aimed to be complete, or account for an accurate historical record of the field.Comment: Submitted for the Snowmass 2013 e-Proceedings with 44 pages, 10 figures, and 3 table

Differential expression of α- and β-expansin genes in the elongating leaf of Festuca pratensis

Grasses contain a number of genes encoding both α- and β-expansins. These cell wall proteins are predicted to play a role in cell wall modifications, particularly during tissue elongation. We report here on the characterisation of five α- and three vegetative β-expansins expressed in the leaf elongation zone (LEZ) of the forage grass, Festuca pratensis Huds. The expression of the predominant α-expansin (FpExp2) was localised to the vascular tissue, as was the β-expansin FpExpB3. Expression of another β-expansin (FpExpB2) was not localised to vascular tissue but was highly expressed in roots and initiating tillers. This is the first description of vegetative β-expansin gene expression at the organ and tissue level and also the first evidence of differential expression between members of this gene family. In addition, an analysis of both α- and β-expansin expression along the LEZ revealed no correlation with growth rate distribution, whereas we were able to identify a novel xyloglucan endotransglycosylase (FpXET1) whose expression profile closely mimicked leaf growth rate. These data suggest that α- and β-expansin activities in the grass leaf are associated with tissue differentiation, that expansins involved in leaf growth may represent more minor components of the spectrum of expansin genes expressed in this tissue, and that XETs may be useful markers for the analysis of grass leaf growth