442 research outputs found
Detecting the position of non-linear component in periodic structures from the system responses to dual sinusoidal excitations
Based on the Nonlinear Output Frequency Response Functions (NOFRFs), a novel method is developed to detect the position of nonlinear components in periodic structures. The detection procedure requires exciting the nonlinear systems twice using two sinusoidal inputs separately. The frequencies of the two inputs are different; one frequency is twice as high as the other one. The validity of this method is demonstrated by numerical studies. Since the position of a nonlinear component often corresponds to the location of defect in periodic structures, this new method is of great practical significance in fault diagnosis for mechanical and structural systems
Masters of the machinery: The politics of economic modelling within European Union energy policy
Economic modelling plays a major role in the development, justification and evaluation of energy policies. However, there has been little investigation of how political dynamics systematically influence these models' development and outputs, or the implications for energy strategies, targets and interventions. Using in-depth interviews with 24 European modellers and policyworkers, we illuminate the politics of economic modelling within European Union (EU) energy policymaking, focusing on dynamics of contestation, differentiated influence and power relations within models' a) framing of questions and problems; b) framing of scenarios and solutions; c) structural assumptions and d) definition of quantitative data inputs. We then consider deeper questions of e) access and exclusion, showing how modelling is used to silence critical voices and reinforce incumbent interests. We argue that understanding this politics of modelling is crucial to the implementation of sustainable energy transitions. We conclude with recommendations for researchers and policyworkers seeking to promote the use of alternative/innovative models in energy policy (within and beyond the EU), centring on reflexivity; recognition; and relationship-building. Developing multi-sectoral ‘communities of practice’ around innovative modelling approaches is vital in challenging a vicious circle of evidence and policy that legitimises business-as-usual in a dangerously warming world
Association between maternal haemoglobin and stillbirth: a cohort study among a multi-ethnic population in England
© 2017 The Authors. Published by Wiley. This is an open access article available under a Creative Commons licence.
The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1111/bjh.14961The study objectives were to examine the association of maternal haemoglobin with stillbirth and perinatal death in a multi-ethnic population in England. We conducted a retrospective cohort analysis using anonymised maternity data from 14 001 women with singleton pregnancies ≥24 weeks’ gestation giving birth between 2013 and 2015 in two hospitals - the Royal Wolverhampton NHS Trust and Guy's and St Thomas’ NHS Foundation Trust. Multivariable logistic regression analyses were undertaken to analyse the associations between maternal haemoglobin at first visit and at 28 weeks with stillbirth and perinatal death, adjusting for 11 other risk factors. Results showed that 46% of the study population had anaemia (haemoglobin <110 g/l) at some point during their pregnancy. The risk of stillbirth and perinatal death decreased linearly per unit increase in haemoglobin concentration at first visit (adjusted odds ratio [aOR] stillbirth = 0·70, 95% confidence interval [CI] 0·58–0·85, aOR perinatal death = 0·71, 95% CI 0·60–0·84) and at 28 weeks (aOR stillbirth = 0·83, 95% CI 0·66–1·04; aOR perinatal death = 0·86, 95%CI 0·67–1·12). Compared with women with haemoglobin ≥110 g/l, the risk of stillbirth and perinatal death was five- and three-fold higher in women with moderate-severe anaemia (haemoglobin <100 g/l) at first visit and 28 weeks, respectively. These findings have clinical and public health importance.This paper presents independent research funded by the National Institute for Health Research (NIHR) as part of a Professorship award to Marian Knight. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Published versio
Using spatiotemporal modulation to draw tactile patterns in mid-air
No description supplie
Most Likely Transformations
We propose and study properties of maximum likelihood estimators in the class
of conditional transformation models. Based on a suitable explicit
parameterisation of the unconditional or conditional transformation function,
we establish a cascade of increasingly complex transformation models that can
be estimated, compared and analysed in the maximum likelihood framework. Models
for the unconditional or conditional distribution function of any univariate
response variable can be set-up and estimated in the same theoretical and
computational framework simply by choosing an appropriate transformation
function and parameterisation thereof. The ability to evaluate the distribution
function directly allows us to estimate models based on the exact likelihood,
especially in the presence of random censoring or truncation. For discrete and
continuous responses, we establish the asymptotic normality of the proposed
estimators. A reference software implementation of maximum likelihood-based
estimation for conditional transformation models allowing the same flexibility
as the theory developed here was employed to illustrate the wide range of
possible applications.Comment: Accepted for publication by the Scandinavian Journal of Statistics
2017-06-1
Peripheral T cell lymphoma, not otherwise specified (PTCL-NOS). A new prognostic model developed by the International T cell Project Network
Different models to investigate the prognosis of peripheral T cell lymphoma not otherwise specified (PTCL-NOS) have been developed by means of retrospective analyses. Here we report on a new model designed on data from the prospective T Cell Project. Twelve covariates collected by the T Cell Project were analysed and a new model (T cell score), based on four covariates (serum albumin, performance status, stage and absolute neutrophil count) that maintained their prognostic value in multiple Cox proportional hazards regression analysis was proposed. Among patients registered in the T Cell Project, 311 PTCL-NOS were retained for study. At a median follow-up of 46\ua0months, the median overall survival (OS) and progression-free survival (PFS) was 20 and 10\ua0months, respectively. Three groups were identified at low risk (LR, 48 patients, 15%, score 0), intermediate risk (IR, 189 patients, 61%, score 1\u20132), and high risk (HiR, 74 patients, 24%, score 3\u20134), having a 3-year OS of 76% [95% confidence interval 61\u201388], 43% [35\u201351], and 11% [4\u201321], respectively (P\ua0<\ua00\ub7001). Comparing the performance of the T cell score on OS to that of each of the previously developed models, it emerged that the new score had the best discriminant power. The new T cell score, based on clinical variables, identifies a group with very unfavourable outcomes
Prevalence of anxiety symptomatology and diagnosis in syndromic intellectual disability: a systematic review and meta-analysis
Individuals with syndromic intellectual disability are at increased risk of experiencing anxiety. Comparing prevalence estimates of anxiety will allow the identification of at-risk groups and inform causal pathways of anxiety. No known study has explored estimates of anxiety symptomatology and diagnosis, including specific anxiety profiles, across groups whilst accounting for methodological quality of studies. This systematic review and meta-analysis aimed to fill this gap. Prior to review completion, methodology and analysis plans were registered and documented in a protocol (CRD42019123561). Data from 83 papers, involving a pooled sample of 13,708 across eight syndromes were synthesised using a random effects model. Anxiety prevalence ranged from 9% (95% CI: 4-14) in Down syndrome to 73% in Rett syndrome (95% CI: 70-77). Anxiety prevalence across syndromic intellectual disability was higher than for intellectual disability of mixed aetiology and general population estimates. Substantial variability between syndromes identified groups at higher risk than others. The identification of high-risk groups is crucial for early intervention, allowing us to refine models of risk and identify divergent profiles
Longer telomere length in peripheral white blood cells is associated with risk of lung cancer and the rs2736100 (CLPTM1L-TERT) polymorphism in a prospective cohort study among women in China.
A recent genome-wide association study of lung cancer among never-smoking females in Asia demonstrated that the rs2736100 polymorphism in the TERT-CLPTM1L locus on chromosome 5p15.33 was strongly and significantly associated with risk of adenocarcinoma of the lung. The telomerase gene TERT is a reverse transcriptase that is critical for telomere replication and stabilization by controlling telomere length. We previously found that longer telomere length measured in peripheral white blood cell DNA was associated with increased risk of lung cancer in a prospective cohort study of smoking males in Finland. To follow up on this finding, we carried out a nested case-control study of 215 female lung cancer cases and 215 female controls, 94% of whom were never-smokers, in the prospective Shanghai Women's Health Study cohort. There was a dose-response relationship between tertiles of telomere length and risk of lung cancer (odds ratio (OR), 95% confidence interval [CI]: 1.0, 1.4 [0.8-2.5], and 2.2 [1.2-4.0], respectively; P trend = 0.003). Further, the association was unchanged by the length of time from blood collection to case diagnosis. In addition, the rs2736100 G allele, which we previously have shown to be associated with risk of lung cancer in this cohort, was significantly associated with longer telomere length in these same study subjects (P trend = 0.030). Our findings suggest that individuals with longer telomere length in peripheral white blood cells may have an increased risk of lung cancer, but require replication in additional prospective cohorts and populations
Diurnal cortisol patterns are associated with physical performance in the Caerphilly Prospective Study
Background Cross-sectional studies have suggested that elevated cortisol is associated with worse physical performance, a surrogate of ageing. We examined the relationship between repeat cortisol measures over 20 years and physical performance in later life
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