3,058 research outputs found
Lifecourse social position and D-dimer; findings from the 1958 British birth cohort
No full textThe aim is to examine the association of lifecourse socioeconomic position (SEP) on circulating levels of D-dimer. Data from the 1958 British birth cohort were used, social class was determined at three stages of respondents' life: at birth, at 23 and at 42 years. A cumulative indicator score of SEP (CIS) was calculated ranging from 0 (always in the highest social class) to 9 (always in the lowest social class). In men and women, associations were observed between CIS and D-dimer (P<0.05). Thus, the respondents in more disadvantaged social classes had elevated levels of D-dimer compared to respondents in less disadvantaged social class. In multivariate analyses, the association of disadvantaged social position with D-dimer was largely explained by fibrinogen, C-reactive protein and von Willebrand Factor in women, and additionally by smoking, alcohol consumption and physical activity in men. Socioeconomic circumstances across the lifecourse at various stages also contribute independently to raised levels of D-dimer in middle age in women only. Risk exposure related to SEP accumulates across life and contributes to raised levels of D-dimer. The association of haemostatic markers and social differences in health may be mediated by inflammatory and other markers
Aspects of identity in the work of Douglas Strachan (1875-1950)
No full textThis thesis explores facets of Scottish identity via the decorative work of Douglas Strachan. Nations and nationalism remain extraordinarily potent phenomena in the contemporary world and this work seeks to examine aspects of Scottish nationhood and cultural identity through Strachan's evocation of history, folklore, religion and myth. It has been argued that these are the chief catalysts for enabling people to define and shape their understanding of themselves and their place within society. Cultural identity is often understood as a passive form of nationalism which is remote from its political counterpart. Yet there are strong arguments to counter this belief. This thesis addresses some of the issues raised by such arguments and adopts an ethno-symbolic approach in order to re-evaluate Strachan's work, and that of his contemporaries. The thesis also develops the theoretical and contextual debates concerning the decorative arts in general and stained glass in particular in order to raise awareness of its merits and its role within our society
On the central role of Somers' D
No full textSomers' D and Kendall's tau-a are parameters behind rank or nonparametric statistics, interpreted as differences between proportions. Given two bivariate data pairs (X1, Y1) and (X2, Y2), Kendall’s tau-a parameter tau-XY is the difference between the probability that the two X–Y pairs are concordant and the probability that the two X–Y pairs are discordant, and Somers' D parameter DYX is the difference between the corresponding conditional probabilities, given that the X-values are ordered. The somersd package computes confidence intervals for both parameters. The Stata 9 version of somersd uses Mata to increase computing speed and greatly extends the definition of Somers' D, allowing the X and/or Y variables to be left- or right-censored and allowing multiple versions of Somers' D for multiple sampling schemes for the X–Y pairs. In particular, we may define stratified versions of Somers' D, in which we compare only X–Y pairs from the same stratum. The strata may be defined by grouping a Rubin–Rosenbaum propensity score, based on the values of multiple confounders for an association between exposure variable X and an outcome variable Y . Therefore, rank statistics can have not only confidence intervals but also confounder-adjusted confidence intervals. Usually, we either estimate DYX as a measure of the effect of X on Y , or we estimate DXY as a measure of the performance of X as a predictor of Y, compared with other predictors. Alternative rank-based measures of the effect of X on Y include the Hodges–Lehmann median difference and the Theil–Sen median slope, both of which are defined in terms of Somers' D.
Implementation of a new bi-directional solar modelling method for complex facades within the ESP-r building simulation program
No full textThis paper provides an overview of a new method for modelling the total solar energy transmittance. It is implemented in the ESP-r building simulation program to model complex façades such as double glazed façades with external, internal or integrated shading devices. This new model has been validated and tested for several cases. The new model required changes to the solar control simulation algorithm and the user interface, so a new “Advanced optics menu” was also introduced into ESP-r. The paper presents the interface development and application of the new technique to different simulation configurations (especially different complex façades with shading devices) in a standard office building
Observation of d(d,p)t reactions in the Princeton Large Torus
No full textProtons from d(d,p)t fusion reactions have been observed in the Princeton Large Torus (PLT) using a surface-barrier detector. The time evolution of the escaping protons agrees with the d-d neutron evolution. The proton energy spectrum was measured during ohmic, lower-hybrid, and ICRF heating. The proton spectrum during lower-hybrid heating indicates non-thermal enhancement of the d-d fusion rate
Inference of disease associations with unmeasured genetic variants by combining results from genome-wide association studies with linkage disequilibrium patterns in a reference data set.
No full textResults from whole-genome association studies of many common diseases are now available. Increasingly, these are being incorporated into meta-analyses to increase the power to detect weak associations with measured single-nucleotide polymorphisms (SNPs). Imputation of genotypes at unmeasured loci has been widely applied using patterns of linkage disequilibrium (LD) observed in the HapMap panels, but there is a need for alternative methods that can utilize the pooled effect estimates from meta-analyses and explore possible associations with SNPs and haplotypes that are not included in HapMap.By a weighted average technique, we show that association results for common SNPs in an observed data set can be scaled and combined to infer the effect of a genetic variant that has been measured only in an independent reference data set. We show that the ratio p(R-1)/[1 + p(R-1)], where R is the relative risk associated with a measured or unmeasured allele of frequency p, is appropriately scaled by 1/D' and weighted in proportion to r2, both common measures of LD being derived from the reference data set.We illustrate this computationally simple method by combining the results of a genome-wide association screen from the North American Rheumatoid Arthritis Consortium with LD measures from the British 1958 Birth Cohort, and explore the validity of underlying assumptions about the generalizability of LD from one population to another, and from healthy subjects to subjects with clinical disease
Researching in cross cultural contexts: a socially just process.
No full textIn this paper, we explore culture and its relationship to cross cultural research. The context for this research is Vanuatu, a small South Pacific Island nation. The action research process used was a collaboration between two New Zealand academics, two Ni Vanuatu women researchers and 13 participants over a two year period. The focus of the action research was the design and delivery of a culturally appropriate educational leadership development programme for women. The collaborative research process raised a number of ethical and methodological considerations, for example, the importance of mutually respectful relationships, working in partnership, collaboration, capacity building, transparent communication and consideration of the local context. Using stories from the Vanuatu context, we illustrate how we navigated culture to be able to research in socially just ways. Being involved in socially just, cross cultural research calls for a thoughtful, well-designed and culturally informed approach throughout all stages of the research process, from initial planning through to follow up and capacity building and finally, the sharing of research findings
Redundancy and Analog Slicing for Precise In-Memory Machine Learning--Part II: Applications and Benchmark
No full textIn-memory computing (IMC) is attracting interest for accelerating data-intensive computing tasks, such as artificial intelligence (AI), machine learning (ML), and scientific calculus. IMC is typically conducted in the analog domain in crosspoint arrays of resistive random access memory (RRAM) devices or memristors. However, the precision of analog operations can be hindered by various sources of noise, such as the nonlinearity of the circuit components and the programming variations due to stuck devices and stochastic switching. Here we demonstrate high-precision IMC by a custom program-verify algorithm that uses redundancy to limit the impact of stuck devices and analog slicing to encode the analog programming error in a separate memory cell. The PageRank problem, consisting of the calculation of the principal eigenvector, is shown as a reference problem, adopting a fully integrated RRAM circuit. We extend these results to also include a convolutional neural network (CNN). We demonstrate a computing accuracy of 6.7 equivalent number of bits (ENOBs). Finally, we compare our results to the solution of the same problem by a static random access memory (SRAM)-based IMC, showcasing an advantage for the RRAM implementation in terms of energy efficiency and scaling
Redundancy and Analog Slicing for Precise in-Memory Machine Learning--Part I: Programming Techniques
No full textIn-memory computing (IMC) is receiving considerable interest for accelerating artificial intelligence (AI) tasks, such as neural network training and inference. However, IMC can also accelerate other machine learning (ML) and scientific computing problems, such as recommendation systems, regression, and PageRank, which are ubiquitous in datacenters. These applications typically have higher precision requirements than neural networks, which can challenge analog-based IMC and sacrifice some of the expected energy efficiency benefits. In this article, we address these challenges experimentally, presenting new techniques improving the accuracy of the solution of linear algebra problems, such as eigenvector extraction for PageRank, in a fully integrated circuit (IC) with analog resistive random access memory (RRAM) devices. Our custom redundancy algorithm can improve the programming accuracy by using multiple memory devices for representing a single matrix entry. Accuracy is further improved by error compensation with analog slicing, which allows an ever more precise value representation
Vaccinations, infections and antibacterials in the first grass pollen season of life and risk of later hayfever
No full textPublished source: Bremner, S. A., Carey, I. M., DeWilde, S., Richards, N., Maier, W. C., Hilton, S. R., Strachan, D. P. and Cook, D. G. (2007), Vaccinations, infections and antibacterials in the first grass pollen season of life and risk of later hayfever. Clinical & Experimental Allergy, 37: 512–517. doi: 10.1111/j.1365-2222.2007.02697.
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