2D vector field simplification based on robustness

pre-printVector field simplification aims to reduce the complexity of the flow by removing features in order of their relevance and importance, to reveal prominent behavior and obtain a compact representation for interpretation. Most existing simplification techniques based on the topological skeleton successively remove pairs of critical points connected by separatrices, using distance or area-based relevance measures. These methods rely on the stable extraction of the topological skeleton, which can be difficult due to instability in numerical integration, especially when processing highly rotational flows. These geometric metrics do not consider the flow magnitude, an important physical property of the flow. In this paper, we propose a novel simplification scheme derived from the recently introduced topological notion of robustness, which provides a complementary view on flow structure compared to the traditional topological-skeleton-based approaches. Robustness enables the pruning of sets of critical points according to a quantitative measure of their stability, that is, the minimum amount of vector field perturbation required to remove them. This leads to a hierarchical simplification scheme that encodes flow magnitude in its perturbation metric. Our novel simplification algorithm is based on degree theory, has fewer boundary restrictions, and so can handle more general cases. Finally, we provide an implementation under the piecewise-linear setting and apply it to both synthetic and real-world datasets

Data management and analysis with WRF and SFIRE

pre-printWe introduce several useful utilities in development for the creation and analysis of real wildland fire simulations using WRF and SFIRE. These utilities exist as standalone programs and scripts as well as extensions to other well known software. Python web scrapers automate the process of downloading and preprocessing atmospheric and surface data from common sources. Other scripts simplify the domain setup by creating parameter files automatically. Integration with Google Earth allows users to explore the simulation in a 3D environment along with real surface imagery. Postprocessing scripts provide the user with a number of output data formats compatible with many commonly used visualization suites allowing for the creation of high quality 3D renderings. As a whole, these improvements build toward a unified web application that brings a sophisticated wildland fire modeling environment to scientists and users alike

Cache ensemble analysis for understanding algorithmic memory performance

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Extraordinary Writs: A Powerful Tool for the Florida Practitioner

This article explores the distinctive nature of extraordinary writs and their availability in the Florida courts. Recent decisional and statutory law in this area is analyzed in detail. The authors\u27 presentation affords Florida practitioners valuable guidelines for the effective invocation of extraordinary writs

Prism Adaptation in Parkinson's Disease

Prism adaptation is impaired by lesions in the basal ganglia in non-human primates, suggesting that this area is involved in this form of visuomotor learning. We investigated the ability of patients with Parkinson's disease to prism adapt. Patients and controls wore prisms which deflected vision laterally by 11 degrees. After baseline testing with a localisation task that permitted no feedback about performance accuracy, prism adaptation was tested at 4 minute intervals over a 28 minute trial. All subjects erred initially, reaching too far to the left of the target, but a separate pointing task encouraged adaptation and reaching error decreased at a similar rate in Parkinsonians and controls. Immediately after the prisms were removed, all subjects reached to the right of the target. This negative after effect was present in controls but not patients when assessed 4 minutes later, suggesting that the patients could not maintain the new sensorimotor relationship imposed by the prisms after their removal. This is similar to performance on visuospatial and executive tasks in Parkinsonians, where ongoing behaviour cannot be modulated without external guidance

A survey of long-term X-ray variability in cool stars

X-ray variability in cool stars can be indicative of coronal magnetic field changes and reconfiguration from a variety of phenomena, including flare events (typical timescales of minutes – hours), active-region evolution (hours – days – weeks), rotational modulation (hours – days – weeks), and activity cycles (years – decades). As part of the EXTraS project (Exploring the X-ray transient and variable sky - http://www.extras-fp7.eu/ ), we are performing a survey of ‘long-term’ X-ray variability using the ~decade-long public database of XMM-Newton observations. We are thus focussing here on timescales from ~a day to ~a decade, using average flux values from individual XMM-Newton observations. Though the resulting sampling is often highly non-uniform in time, the light-curves can provide valuable insights into the magnetic activity outside of shorter-term flaring episodes. We have taken a number of stellar samples (Hipparcos-Tycho, Simbad …) and are evaluating the statistical properties of the flux distributions, and comparing these across, for example spectral type, and with previously-published estimates. We are also examining the potential effects of flare events on the apparent long-term variability estimates. We give a preliminary report both on the overall variability distributions and extreme cases, distinguishing between serendipitously-observed stars (yielding, in some sense an unbiased sample) and XMM-Newton target objects (a number of them already reported by other authors)

Phylogeography of Japanese encephalitis virus:genotype is associated with climate

The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate

The Lantern Vol. 66, No. 2, Spring 1999

• Dowry • The Ballad of the Lonely Thinker • Dissipation • Parliament Light • Reflecting Hood • Tonight • Decree • Not Yet • The Man in the Moon • The Sound and/or Fury • Uh Huh • Watch • The Futility of a Drizzle in a Worsening Draught • The Answering Machine • Felix Culpa • Kiss Off • Amorous • Summer of the Burning Pizzas • Life Without Shoelaces • Hermes and Aphrodite • Win! Twins! • From 69 Slices of Hell • Boardwalk Cowboyhttps://digitalcommons.ursinus.edu/lantern/1154/thumbnail.jp

Creativity and commerce: Michael Klinger and new film history

The crisis in film studies and history concerning their legitimacy and objectives has provoked a reinvigoration of scholarly energy in historical enquiry. 'New film history' attempts to address the concerns of historians and film scholars by working self-reflexively with an expanded range of sources and a wider conception of 'film' as a dynamic set of processes rather than a series of texts. The practice of new film history is here exemplified through a detailed case study of the independent British producer Michael Klinger (active 1961-87) with a specific focus on his unsuccessful attempt to produce a war film, Green Beach, based on a memoir of the Dieppe raid (August 1942). This case study demonstrates the importance of analysing the producer's role in understanding the complexities of film-making, the continual struggle to balance the competing demands of creativity and commerce. In addition, its subject matter - an undercover raid and a Jewish hero - disturbed the dominant myths concerning the Second World War, creating what turned out to be intractable ideological as well as financial problems. The paper concludes that the concerns of film historians need to engage with broader cultural and social histories. © 2010 Taylor & Francis