Particle displacements in the elastic deformation of amorphous materials: local fluctuations vs. non-affine field

We study the local disorder in the deformation of amorphous materials by decomposing the particle displacements into a continuous, inhomogeneous field and the corresponding fluctuations. We compare these fields to the commonly used non-affine displacements in an elastically deformed 2D Lennard-Jones glass. Unlike the non-affine field, the fluctuations are very localized, and exhibit a much smaller (and system size independent) correlation length, on the order of a particle diameter, supporting the applicability of the notion of local "defects" to such materials. We propose a scalar "noise" field to characterize the fluctuations, as an additional field for extended continuum models, e.g., to describe the localized irreversible events observed during plastic deformation.Comment: Minor corrections to match the published versio

Public Misunderstanding of Science? Reframing the Problem of Vaccine Hesitancy

The public rejection of scientific claims is widely recognized by scientific and governmental institutions to be threatening to modern democratic societies. Intense conflict between science and the public over diverse health and environmental issues have invited speculation by concerned officials regarding both the source of and the solution to the problem of public resistance towards scientific and policy positions on such hot-button issues as global warming, genetically modified crops, environmental toxins, and nuclear waste disposal. The London Royal Society’s influential report “Public Understanding of Science”, which spearheaded the now-thriving area of science..

Iconoclast or Creed? Objectivism, pragmatism, and the hierarchy of evidence

Because “evidence” is at issue in evidence-based medicine (EBM), the critical responses to the movement have taken up themes from post-positivist philosophy of science to demonstrate the untenability of the objectivist account of evidence. While these post-positivist critiques seem largely correct, I propose that when they focus their analyses on what counts as evidence, the critics miss important and desirable pragmatic features of the evidence-based approach. This article redirects critical attention toward EBM’s rigid hierarchy of evidence as the culprit of its objectionable epistemic practices. It reframes the EBM discourse in light of a distinction between objectivist and pragmatic epistemology, which allows for a more nuanced analysis of EBM than previously offered: one that is not either/or in its evaluation of the decision-making technology as either iconoclastic or creedal

A study of the dynamics of rotating space stations with elastically connected counterweight and attached flexible appendages. Volume 1: Theory

The formulation of a mathematical model for predicting the dynamic behavior of rotating flexible space station configurations was conducted. The overall objectives of the study were: (1) to develop the theoretical techniques for determining the behavior of a realistically modeled rotating space station, (2) to provide a versatile computer program for the numerical analysis, and (3) to present practical concepts for experimental verification of the analytical results. The mathematical model and its associated computer program are described

Domino: exploring mobile collaborative software adaptation

Social Proximity Applications (SPAs) are a promising new area for ubicomp software that exploits the everyday changes in the proximity of mobile users. While a number of applications facilitate simple file sharing between co–present users, this paper explores opportunities for recommending and sharing software between users. We describe an architecture that allows the recommendation of new system components from systems with similar histories of use. Software components and usage histories are exchanged between mobile users who are in proximity with each other. We apply this architecture in a mobile strategy game in which players adapt and upgrade their game using components from other players, progressing through the game through sharing tools and history. More broadly, we discuss the general application of this technique as well as the security and privacy challenges to such an approach

Greater response variability in adolescents is associated with increased white matter development.

Adolescence is a period of learning, exploration, and continuous adaptation to fluctuating environments. Response variability during adolescence is an important, understudied, and developmentally appropriate behavior. The purpose of this study was to identify the association between performance on a dynamic risky decision making task and white matter microstructure in a sample of 48 adolescents (14-16 years). Individuals with the greatest response variability on the task obtained the widest range of experience with potential outcomes to risky choice. When compared with their more behaviorally consistent peers, adolescents with greater response variability rated real-world examples of risk taking behaviors as less risky via self-report. Tract-Based Spatial Statistics (TBSS) were used to examine fractional anisotropy (FA) and mean diffusivity (MD). Greater FA in long-range, late-maturing tracts was associated with higher response variability. Greater FA and lower MD were associated with lower riskiness ratings of real-world risky behaviors. Results suggest that response variability and lower perceived risk attitudes of real-world risk are supported by neural maturation in adolescents

Long QT Syndrome

The hereditary long QT syndrome (LQTS) is a genetic channelopathy with variable penetrance that is associated with increased propensity to syncope, polymorphous ventricular tachycardia (torsades de pointes), and sudden arrhythmic death. This inherited cardiac disorder constitutes an important cause of malignant ventricular arrhythmias and sudden cardiac death in young individuals with normal cardiac morphology. Risk assessment in affected LQTS patients relies upon a constellation of electrocardiographic, clinical, and genetic factors. Administration of beta-blockers is the mainstay therapy in affected patients, and primary prevention with an implantable cardioverter defibrillator or left cervicothoracic sympathetic denervation are therapeutic options in patients who remain symptomatic despite beta-blocker therapy. Accumulating data from the International LQTS Registry have recently facilitated a comprehensive analysis of risk factors for aborted cardiac arrest or sudden cardiac death in pre-specified age groups, including the childhood, adolescence, adulthood, and post-40 periods. These analyses have consistently indicated that the phenotypic expression of LQTS is time dependent and age specific, warranting continuous risk assessment in affected patients. Furthermore, the biophysical function, type, and location of the ion-channel mutation are currently emerging as important determinants of outcome in genotyped patients. These new data may be used to improve risk stratification and for the development of gene-specific therapies that may reduce the risk of life-threatening cardiac events in patients with this inherited cardiac disorder

Frequency drives lexical access in reading but not in speaking: the frequency-lag hypothesis

To contrast mechanisms of lexical access in production versus comprehension we compared the effects of word frequency (high, low), context (none, low constraint, high constraint), and level of English proficiency (monolingual, Spanish-English bilingual, Dutch-English bilingual) on picture naming, lexical decision, and eye fixation times. Semantic constraint effects were larger in production than in reading. Frequency effects were larger in production than in reading without constraining context but larger in reading than in production with constraining context. Bilingual disadvantages were modulated by frequency in production but not in eye fixation times, were not smaller in low-constraint contexts, and were reduced by high-constraint contexts only in production and only at the lowest level of English proficiency. These results challenge existing accounts of bilingual disadvantages and reveal fundamentally different processes during lexical access across modalities, entailing a primarily semantically driven search in production but a frequency-driven search in comprehension. The apparently more interactive process in production than comprehension could simply reflect a greater number of frequency-sensitive processing stages in production

Exact Computation of Influence Spread by Binary Decision Diagrams

Evaluating influence spread in social networks is a fundamental procedure to estimate the word-of-mouth effect in viral marketing. There are enormous studies about this topic; however, under the standard stochastic cascade models, the exact computation of influence spread is known to be #P-hard. Thus, the existing studies have used Monte-Carlo simulation-based approximations to avoid exact computation. We propose the first algorithm to compute influence spread exactly under the independent cascade model. The algorithm first constructs binary decision diagrams (BDDs) for all possible realizations of influence spread, then computes influence spread by dynamic programming on the constructed BDDs. To construct the BDDs efficiently, we designed a new frontier-based search-type procedure. The constructed BDDs can also be used to solve other influence-spread related problems, such as random sampling without rejection, conditional influence spread evaluation, dynamic probability update, and gradient computation for probability optimization problems. We conducted computational experiments to evaluate the proposed algorithm. The algorithm successfully computed influence spread on real-world networks with a hundred edges in a reasonable time, which is quite impossible by the naive algorithm. We also conducted an experiment to evaluate the accuracy of the Monte-Carlo simulation-based approximation by comparing exact influence spread obtained by the proposed algorithm.Comment: WWW'1