This is a working paper for IFIP Working Group 2.5 (Numerical Software) to stimulate discussion of a possible group project. The project is to describe the facilities in a programming language that make it useful for numerical computation. The facilities are classified and their importance measured. This paper presents a framework for this project and is an initial draft of the facility descriptions. The opinions and ratings contained here are those of the author and do not reflect a consensus of IFIP WG 2.5. (Author)
Through a simple analytical description we quantify how pressure-driven flows over grooved surfaces develop transverse components, which, for shallow grooves, can be modeled with simple anisotropic effective boundary conditions. Helical recirculation results in channels or capillaries with grooved walls. An experimental validation of our model is presented. Our analysis provides a workable guide for the design of 3D flows with simple patterns of grooved regions, e.g., to control the position of streams in the cross section of a channel or to promote mixing. Potential applications in microfluidics are outlined.
This paper addresses testing of compressed structures, such as shells, that exhibit catastrophic buckling and notorious imperfection sensitivity. The central concept is the probing of a loaded structural specimen by a controlled lateral displacement to gain quantitative insight into its buckling behavior and to measure the energy barrier against buckling. This can provide design information about a structure’s stiffness and robustness against buckling in terms of energy and force landscapes. Developments in this area are relatively new but have proceeded rapidly with encouraging progress. Recent experimental tests on uniformly compressed spherical shells, and axially loaded cylinders, show excellent agreement with theoretical solutions. The probing technique could be a valuable experimental procedure for testing prototype structures, but before it can be used a range of potential problems must be examined and solved. The probing response is highly nonlinear and a variety of complications can occur. Here, we make a careful assessment of unexpected limit points and bifurcations, that could accompany probing, causing complications and possibly even collapse of a test specimen. First, a limit point in the probe displacement (associated with a cusp instability and fold) can result in dynamic buckling as probing progresses, as demonstrated in the buckling of a spherical shell under volume control. Second, various types of bifurcations which can occur on the probing path which result in the probing response becoming unstable are also discussed. To overcome these problems, we outline the extra controls over the entire structure that may be needed to stabilize the response.
Background Asthma and obesity are common diseases with considerable impact on public health. Prospective studies showed that obesity is a risk factor for developing asthma and a causal relation has been proposed. However, there is limited evidence for the existence of shared genetic effects and it is not yet clear how obesity and genetic factors jointly influence the risk of developing asthma. Objective We sought to determine whether obesity (body mass index of 30 or greater) modifies the risk of developing asthma and to assess whether there is evidence for a causal relation linking the genetic risk of developing obesity with asthma. Methods The analyses were performed in genotyped individuals of two northern Finland birth cohorts. The discovery set (NFBC1966) and the in silico replication set (NFBC1986) comprised a sample of 4182 and 1441 individuals. The presence of asthma was determined by self-report of a physician diagnosis of asthma, and body mass index (BMI) was measured at time of clinical examination (at 31 and 16 years old respectively). Sixty SNPs previously associated with asthma or obesity from the GWAS catalogue were analysed. The gene environment interactions were formally tested with a full interaction model using logistic regression. The significant interactions (Pl0.05) found in the discovery dataset were meta-analysed with results of the replication set using fixed and random effects model. Results We prioritized six significant (Pl0.05) SNP interactions in the discovery set for replication (Fig. 1). Only one of the prioritized loci was previously associated with obesity (BMI). After meta-analysis with the replication set, we identified one directionally consistent interaction with obesity (P l 6.5x10-3) in rs2786098 near DENND1B, a SNP previously associated with asthma (Fig. 2). After meta-analysis, we did not find significant or directionally consistent interactions in SNPs previously associated with BMI or Obesity. Conclusion Our limited dataset suggests that obesity modifies the genetic risk of developing asthma. We did not found evidence for the hypothesis that obesity causes asthma.
Here we present a novel visible analog computing approach for solving a wide class of shortest path problems. Using a microfluidic chip for computation, based on the lighting up of a glow discharge, the solution to maze search problems, the solution of a network shortest path and k-shortest paths problems and the practical application of finding the shortest paths between several landmarks from a street map are presented. The solution and visible display (in real time) for these problems shows only a small difference in practical problem solving time among problems with varying differences in size.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTris[3-(tert-butylhydroxymethylene)-d-camphorato]europium(III). A reagent for determining enantiomeric purityGeorge M. Whitesides and Daniel William LewisCite this: J. Am. Chem. Soc. 1970, 92, 23, 6979–6980Publication Date (Print):November 1, 1970Publication History Published online1 May 2002Published inissue 1 November 1970https://pubs.acs.org/doi/10.1021/ja00726a049https://doi.org/10.1021/ja00726a049research-articleACS PublicationsRequest reuse permissionsArticle Views454Altmetric-Citations159LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts