698 research outputs found

    Method of measuring the thickness of radioactive thin films

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    Thickness monitor consists of proportional X-ray counter coupled to pulse counting system, copper filter over face of counter, rotatable collimator containing radioactive source, and rotatable shutter. Monitor can be used as integral part of neutron generator. It has been used to measure titanium tritide film thicknesses from 0.1 to 30 micrometers

    Fishnets: Information-Optimal, Scalable Aggregation for Sets and Graphs

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    Set-based learning is an essential component of modern deep learning and network science. Graph Neural Networks (GNNs) and their edge-free counterparts Deepsets have proven remarkably useful on ragged and topologically challenging datasets. The key to learning informative embeddings for set members is a specified aggregation function, usually a sum, max, or mean. We propose Fishnets, an aggregation strategy for learning information-optimal embeddings for sets of data for both Bayesian inference and graph aggregation. We demonstrate that i) Fishnets neural summaries can be scaled optimally to an arbitrary number of data objects, ii) Fishnets aggregations are robust to changes in data distribution, unlike standard deepsets, iii) Fishnets saturate Bayesian information content and extend to regimes where MCMC techniques fail and iv) Fishnets can be used as a drop-in aggregation scheme within GNNs. We show that by adopting a Fishnets aggregation scheme for message passing, GNNs can achieve state-of-the-art performance versus architecture size on ogbn-protein data over existing benchmarks with a fraction of learnable parameters and faster training time.Comment: 13 pages, 9 figures, 2 tables. Submitted to ICLR 202

    The Cosmic Graph: Optimal Information Extraction from Large-Scale Structure using Catalogues

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    We present an implicit likelihood approach to quantifying cosmological information over discrete catalogue data, assembled as graphs. To do so, we explore cosmological inference using mock dark matter halo catalogues. We employ Information Maximising Neural Networks (IMNNs) to quantify Fisher information extraction as a function of graph representation. We a) demonstrate the high sensitivity of modular graph structure to the underlying cosmology in the noise-free limit, b) show that networks automatically combine mass and clustering information through comparisons to traditional statistics, c) demonstrate that graph neural networks can still extract information when catalogues are subject to noisy survey cuts, and d) illustrate how nonlinear IMNN summaries can be used as asymptotically optimal compressed statistics for Bayesian implicit likelihood inference. We reduce the area of joint Ωm,σ8\Omega_m, \sigma_8 parameter constraints with small (\sim100 object) halo catalogues by a factor of 42 over the two-point correlation function, and demonstrate that the networks automatically combine mass and clustering information. This work utilises a new IMNN implementation over graph data in Jax, which can take advantage of either numerical or auto-differentiability. We also show that graph IMNNs successfully compress simulations far from the fiducial model at which the network is fitted, indicating a promising alternative to nn-point statistics in catalogue-based analyses.Comment: 16 pages, 10 figures. To be submitted to RASTI. We provide code and a tutorial for the analysis and relevant software at https://github.com/tlmakinen/cosmicGraph

    Characterization of the “in vitro pulp chamber” using the cytotoxicity of phenol

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71980/1/j.1600-0714.1989.tb00744.x.pd

    Madison County, Kentucky Hazardous Materials Commodity Flow Analysis

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    This report presents the results of a Commodity Flow Analysis of Hazardous Materials for Interstate-75 (I-75) (North and South Bound lanes) conducted by Western Kentucky University in partnership with the Madison County (Kentucky) Local Emergency Planning Committee (LEPC). The only Kentucky County within the study area is Madison County as shown in Figure 1.1. The purpose of report is to give information on patterns of hazardous materials being transported along I-75 as observed from July 25th 2011 to August 5th 2011. A secondary purpose is to summarize incidents involving hazardous materials over the previous 6 years (January 2006 – June 2011). Finally, this report assesses survey information collected from fixed facilities that ship and receive hazardous materials in the I-75 highway. Commodity flow analysis is necessary in order for the LEPC to prepare for future hazardous material releases that may occur along this section of I-75. Data collected from this study will aid the emergency planning process for specific hazardous materials that were observed to frequent the study area during the study period

    Nomadic devices in the vehicle environment: planning of field operation tests in Europe

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    The market for the Nomadic Devices, such as on-board navigation devices and smart phones, integrated to road vehicles is increasing rapidly today. While providing uselful services for travellers, at the same time, these devices may introduce significant usability and distraction problems, jeopardizing their safety as the devices are not usually specially designed for the vehicle context. Consequently, there is a need to study the impacts of such devices by Field Operational Tests (FOT). TeleFOT (Field Operational Tests of Aftermarket and Nomadic Devices in Vehicles), is a European Commission co-funded integrated project aiming to assess the impacts of aftermarket and nomadic devices used in vehicles for driver support and to raise wide awareness of the functions and potential these devices offer, by implementing Field Operational Tests. To do so it will build, mobilise and integrate European test communities for long term testing and assessment of driver support functions through aftermarket and nomadic devices. It will also work on the related methodological framework

    Oral health promotion: the economic benefits to the NHS of increased use of sugarfree gum in the UK.

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    INTRODUCTION: The effect of sugarfree gum (SFG) on the prevention of dental caries has been established for some time. With increased constraints placed on healthcare budgets, the importance of economic considerations in decision-making about oral health interventions has increased. The aim of this study was to demonstrate the potential cost savings in dental care associated with increased levels of SFG usage. METHODS: The analysis examined the amount of money which would hypothetically be saved if the UK 12-year-old population chewed more SFG. The number of sticks chewed per year and the caries risk reduction were modelled to create a dose response curve. The costs of tooth restoration, tooth extraction in primary care settings and under general anaesthetic were considered, and the effects of caries reduction on these costs calculated. RESULTS: If all members of the UK 12-year-old population chewed SFG frequently (twice a day), the potential cost savings for the cohort over the course of one year were estimated to range from £1.2 to £3.3 million and if they chewed three times a day, £8.2 million could be saved each year. Sensitivity analyses of the key parameters demonstrated that cost savings would still be likely to be observed even in scenarios with less significant increases in SFG use. CONCLUSION: This study shows that if levels of SFG usage in the teenage population in the UK could be increased, substantial cost savings might be achieved

    Long-term effect of xylitol chewing gum on dental caries

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    – About 85% ( n = 269) of the subjects who participated in the Ylivieska follow-up studies on the effect of xylitol chewing gum on dental caries during 1982–84 or 1982–85 were re-examined in 1987 for the analysis of possible long-term preventive effects. Further caries reduction was found 2 or 3 yr after the discontinuation of the use of xylitol. The effect was especially marked in girls; the reduction in caries increment in the post-use years was 60% for the 2-yr users, suggesting that more pronounced caries reduction was associated with the most regular use of xylitol. In teeth erupting during the first year of the use of xylitol gum the long-term preventive effect was greater than in other teeth. Several explanations are suggested: lasting effect of the microbiological changes in the mouth, bacterial colonization on newly erupted teeth by organisms other than S. mutatis , and/or thorough maturation of the teeth under favorable physico-chemical circumstances. The results suggest that the value of xylitol in caries prevention depends on the timing of the treatment in relation to the development of the dentitionPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75700/1/j.1600-0528.1989.tb00611.x.pd

    Metabolomics Applied to Diabetes Research: Moving From Information to Knowledge

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    Type 2 diabetes is caused by a complex set ofinteractions between genetic and environmentalfactors. Recent work has shown that human type2 diabetes is a constellation of disorders associ-ated with polymorphisms in a wide array of genes, with each individual gene accounting for 1 % of disease risk (1). Moreover, type 2 diabetes involves dysfunction of multiple organ systems, including impaired insulin action in muscle and adipose, defective control of hepatic glu-cose production, and insulin deficiency caused by loss of -cell mass and function (2). This complexity presents challenges for a full understanding of the molecular path-ways that contribute to the development of this major disease. Progress in this area may be aided by the recent advent of technologies for comprehensive metabolic anal-ysis, sometimes termed “metabolomics. ” Herein, we sum-marize key metabolomics methodologies, including nuclear magnetic resonance (NMR) and mass spectrome
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