3,242 research outputs found
The application of capillary electrophoresis and liquid chromatography/mass spectrometry to the analysis of anaerobic and cyanoacrylate adhesives
This thesis details the application of separation techniques to the analysis of anaerobic and cyanoacrylate adhesives Chapter 1 is an introduction to adhesives, where the chemistry, composition and analysis of both types of adhesives are discussed.
Chapter 2 represents the analytical study into the determination of the products of decomposition of two reducing agents in anaerobic adhesives. The decomposition of the reducing agents, 1,2,3,4 tetrahydroquinohne and dihydropyndine, in the presence of saccharin, maleic acid, cumene hydroperoxide and the metals, iron and copper, was investigated utilising Liquid Chromatography/Mass Spectrometry. A system was developed which was applied to the LC/MS determination of the products. This chapter also includes a brief discussion on LC/MS and the cure chemistry of the cyanoacrylate adhesives.
In Chapter 3 the application of Capillary Electrophoresis to the separation of basic components found in cyanoacrylate adhesives is detailed. This chapter includes a literature survey on the analysis of basic compounds with Capillary Electrophoresis. An investigation into the optimum system for the separation of piperidine, dipipendinomethane and ethylpipendme carboxylate was carried out. The study includes an assessment of the suitability of a variety of electrolytes for the separation.
In Chapter 4 suggestions for future research are made and conclusions are drawn from the work carried out in the thesis
Flexible context aware interface for ambient assisted living
A Multi Agent System that provides a (cared for) person, the subject, with assistance and support through an Ambient Assisted Living Flexible Interface (AALFI) during the day while complementing the night time assistance offered by NOCTURNAL with feedback assistance, is presented. It has been tailored to the subject’s requirements profile and takes into account factors associated with the time of day; hence it attempts to overcome shortcomings of current Ambient Assisted Living Systems. The subject is provided with feedback that highlights important criteria such as quality of sleep during the night and possible breeches of safety during the day. This may help the subject carry out corrective measures and/or seek further assistance. AALFI provides tailored interaction that is either visual or auditory so that the subject is able to understand the interactions and this process is driven by a Multi-Agent System. User feedback gathered from a relevant user group through a workshop validated the ideas underpinning the research, the Multi-agent system and the adaptable interface
How to reduce your risk of injury from exposure to anhydrous ammonia
SF-962; This circular provides safety information on how to handle anhydrous ammonia. It includes bibliographical reference
Size-and-shape space Gaussian mixture models for structural clustering of molecular dynamics trajectories
Determining the optimal number and identity of structural clusters from an ensemble of molecular configurations continues to be a challenge. Recent structural clustering methods have focused on the use of internal coordinates due to the innate rotational and translational invariance of these features. The vast number of possible internal coordinates necessitates a feature space supervision step to make clustering tractable, but yields a protocol that can be system type specific. Particle positions offer an appealing alternative to internal coordinates, but suffer from a lack of rotational and translational invariance, as well as a perceived insensitivity to regions of structural dissimilarity. Here, we present a method, denoted shape-GMM, that overcomes the shortcomings of particle positions using a weighted maximum likelihood (ML) alignment procedure. This alignment strategy is then built into an expectation maximization Gaussian mixture model (GMM) procedure to capture metastable states in the free energy landscape. The resulting algorithm distinguishes between a variety of different structures, including those indistinguishable by RMSD and pair-wise distances, as demonstrated on several model systems. Shape- GMM results on an extensive simulation of the the fast-folding HP35 Nle/Nle mutant protein support a 4-state folding/unfolding mechanism which is consistent with previous experimental results and provides kinetic detail comparable to previous state of the art clustering approaches, as measured by the VAMP-2 score. Currently, training of shape-GMMs is recommended for systems (or subsystems) that can be represented by . 200 particles and . 100K configurations to estimate high-dimensional covariance matrices and balance computational expense. Once a shape-GMM is trained, it can be used to predict the cluster identities of millions of configurations.Chemistr
Longitudinal LASSO: Jointly Learning Features and Temporal Contingency for Outcome Prediction
Longitudinal analysis is important in many disciplines, such as the study of
behavioral transitions in social science. Only very recently, feature selection
has drawn adequate attention in the context of longitudinal modeling. Standard
techniques, such as generalized estimating equations, have been modified to
select features by imposing sparsity-inducing regularizers. However, they do
not explicitly model how a dependent variable relies on features measured at
proximal time points. Recent graphical Granger modeling can select features in
lagged time points but ignores the temporal correlations within an individual's
repeated measurements. We propose an approach to automatically and
simultaneously determine both the relevant features and the relevant temporal
points that impact the current outcome of the dependent variable. Meanwhile,
the proposed model takes into account the non-{\em i.i.d} nature of the data by
estimating the within-individual correlations. This approach decomposes model
parameters into a summation of two components and imposes separate block-wise
LASSO penalties to each component when building a linear model in terms of the
past measurements of features. One component is used to select features
whereas the other is used to select temporal contingent points. An accelerated
gradient descent algorithm is developed to efficiently solve the related
optimization problem with detailed convergence analysis and asymptotic
analysis. Computational results on both synthetic and real world problems
demonstrate the superior performance of the proposed approach over existing
techniques.Comment: Proceedings of the 21th ACM SIGKDD International Conference on
Knowledge Discovery and Data Mining. ACM, 201
Distributed utterances
I propose an apparatus for handling intrasentential change in context. The standard approach has problems with sentences with multiple occurrences of the same demonstrative or indexical. My proposal involves the idea that contexts can be complex. Complex contexts are built out of (“simple”) Kaplanian contexts by ordered n-tupling. With these we can revise the clauses of Kaplan’s Logic of Demonstratives so that each part of a sentence is taken in a different component of a complex context.
I consider other applications of the framework: to agentially distributed utterances (ones made partly by one speaker and partly by another); to an account of scare-quoting; and to an account of a binding-like phenomenon that avoids what Kit Fine calls “the antinomy of the variable.
Efficacy of hearing conservation education programs for youth and young adults: a systematic review
Abstract
Background
Many youth and young adults experience high noise exposure compounded by lack of access to hearing health education. Although the need for hearing health education programs is evident, the efficacy of these programs for youth is unclear. We evaluated the literature for efficacy of various hearing conservation programs aimed at youth and young adults, and analyzed their strengths and limitations.
Methods
Studies reporting results of hearing conservation or hearing loss prevention programs with youth or young adults, using randomized controlled trials, quasi-experimental designs, experimental design, or qualitative research, and published in peer-reviewed journals in English between 2001 and 2018 were included. Studies were found through searches of selected literature databases (i.e., PubMed, Google Scholar, NIOSH Toxline, and Scopus). Identified publications were assessed for relevance, and data were extracted from the studies deemed relevant.
Results
A total of 10 studies were included. Very little evidence of efficacy of hearing conservation educational programs was found in these studies. Several methodological limitations including lack of rigorous study designs, inadequate power, and application of inappropriate statistical analysis were noted. Some use of technology in programs (e.g., smartphone apps, mobile phone text messages, and computers) was observed, but conclusions as to the effectiveness of these tools were limited by the small number of studies and small sample sizes.
Conclusions
The number of studies of educational hearing conservation programs for youth and young adults was low. The efficacy of the program was not reported in most studies, and it is difficult to draw public health conclusions from these studies due to their multiple methodological limitations. While use of technology in hearing conservation educational programs offers promise, its effectiveness has not been studied.https://deepblue.lib.umich.edu/bitstream/2027.42/146515/1/12889_2018_Article_6198.pd
The distribution of Pearson residuals in generalized linear models
In general, the distribution of residuals cannot be obtained explicitly. We
give an asymptotic formula for the density of Pearson residuals in continuous
generalized linear models corrected to order , where is the sample
size. We define corrected Pearson residuals for these models that, to this
order of approximation, have exactly the same distribution of the true Pearson
residuals. Applications for important generalized linear models are provided
and simulation results for a gamma model illustrate the usefulness of the
corrected Pearson residuals
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