Numerical methods for calculating the response of a deterministic and stochastically excited Duffing oscillator

When compared to independent harmonic or stochastic excitation, there exist relatively few methods to model the response of non-linear systems to a combination of deterministic and stochastic vibration despite the likelihood of harmonic oscillations containing noise in realistic applications. This paper uses the Duffing oscillator to illustrate how the joint probability density function (JPDF) of the displacement and velocity responds to this form of excitation. Monte Carlo simulations were performed to generate the JPDF which was observed, in general, to spread around the trajectory that would be observed if only deterministic excitation was present. In the deterministic chaotic case, the JPDF is known to be a diffuse chaotic attractor when noise is present. This paper assesses the ability of a useful class of methods, global weighted residual methods, to produce the geometrically complex JPDF responses produced from harmonic and white noise excitation. A technique using a JPDF in the form of a Gram–Charlier type C series was found to produce accurate results, although the method fails due to ill-conditioning as the shape of the JPDF required by the dynamics becomes too complex. The authors would like to thank the EPSRC Doctoral Training Award for funding this research.This is the author accepted manuscript. The final version is available from SAGE via http://dx.doi.org/10.1177/095440621560754

Fetal Sex and RHD Genotyping with Digital PCR Demonstrates Greater Sensitivity than Real-time PCR.

BACKGROUND: Noninvasive genotyping of fetal RHD (Rh blood group, D antigen) can prevent the unnecessary administration of prophylactic anti-D to women carrying RHD-negative fetuses. We evaluated laboratory methods for such genotyping. METHODS: Blood samples were collected in EDTA tubes and Streck® Cell-Free DNA™ blood collection tubes (Streck BCTs) from RHD-negative women (n = 46). Using Y-specific and RHD-specific targets, we investigated variation in the cell-free fetal DNA (cffDNA) fraction and determined the sensitivity achieved for optimal and suboptimal samples with a novel Droplet Digital™ PCR (ddPCR) platform compared with real-time quantitative PCR (qPCR). RESULTS: The cffDNA fraction was significantly larger for samples collected in Streck BCTs compared with samples collected in EDTA tubes (P < 0.001). In samples expressing optimal cffDNA fractions (≥4%), both qPCR and digital PCR (dPCR) showed 100% sensitivity for the TSPY1 (testis-specific protein, Y-linked 1) and RHD7 (RHD exon 7) assays. Although dPCR also had 100% sensitivity for RHD5 (RHD exon 5), qPCR had reduced sensitivity (83%) for this target. For samples expressing suboptimal cffDNA fractions (<2%), dPCR achieved 100% sensitivity for all assays, whereas qPCR achieved 100% sensitivity only for the TSPY1 (multicopy target) assay. CONCLUSIONS: qPCR was not found to be an effective tool for RHD genotyping in suboptimal samples (<2% cffDNA). However, when testing the same suboptimal samples on the same day by dPCR, 100% sensitivity was achieved for both fetal sex determination and RHD genotyping. Use of dPCR for identification of fetal specific markers can reduce the occurrence of false-negative and inconclusive results, particularly when samples express high levels of background maternal cell-free DNA

Automatic estimation of harmonic tension by distributed representation of chords

The buildup and release of a sense of tension is one of the most essential aspects of the process of listening to music. A veridical computational model of perceived musical tension would be an important ingredient for many music informatics applications. The present paper presents a new approach to modelling harmonic tension based on a distributed representation of chords. The starting hypothesis is that harmonic tension as perceived by human listeners is related, among other things, to the expectedness of harmonic units (chords) in their local harmonic context. We train a word2vec-type neural network to learn a vector space that captures contextual similarity and expectedness, and define a quantitative measure of harmonic tension on top of this. To assess the veridicality of the model, we compare its outputs on a number of well-defined chord classes and cadential contexts to results from pertinent empirical studies in music psychology. Statistical analysis shows that the model's predictions conform very well with empirical evidence obtained from human listeners.Comment: 12 pages, 4 figures. To appear in Proceedings of the 13th International Symposium on Computer Music Multidisciplinary Research (CMMR), Porto, Portuga

A Bioengineered Implant for a Predetermined Bone Cellular Response to Loading Forces. A Literature Review and Case Report

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142048/1/jper1276.pd

Reproducibility of four frequently used local heating protocols to assess cutaneous microvascular function.

BACKGROUND: Skin microvascular responses to local heating are frequently used to assess microvascular function. Several local heating protocols have been developed, all varying slightly in execution. The aim of this study was to determine the inter-day reproducibility of the four most commonly used local heating protocols in healthy young subjects. METHODS: Fifteen, healthy males (28±5yrs, BMI 25±2kg/m(2)) attended two experimental trials 2-7days apart. During each trial, baseline and maximal thermally stimulated forearm skin responses were examined simultaneously at four sites on the dominant forearm using laser Doppler flowmetry (LDF). The following heating protocols were adopted: 1. Rapid 39°C (0.5°C/5s), 2. Rapid 42°C (0.5°C/5s) 3. Gradual 42°C (0.5°C/2min 30s) and 4. Slow 42°C (0.5°C/5min). The coefficient of variation (CV) was calculated for absolute flux, cutaneous vascular conductance (CVC; flux/mean arterial pressure, MAP) and CVC expressed as a percentage of maximal CVC at 44°C (%CVCmax) at three different time points; baseline (33°C), plateau (39/42°C) and maximal (44°C). RESULTS: Reproducibility of baseline flux, CVC and %CVCmax was 17-29% across all protocols. During the plateau, Rapid, Gradual and Slow 42°C demonstrated a reproducibility of 13-18% for flux and CVC and 5-11% for %CVCmax. However, Rapid 39°C demonstrated a lower reproducibility for flux, CVC and %CVCmax (all 21%). Reproducibility at 44°C was 12-15% for flux and CVC across all protocols. CONCLUSION: This is the first study examining inter-day reproducibility across four local heating protocols. The good-to-moderate reproducibility of the Rapid, Gradual and Slow 42°C protocols support their (simultaneous) use to assess microvascular function. Using Rapid 39°C may require a greater number of subjects to detect differences within subjects

Novel exomphalos genetic mouse model: The importance of accurate phenotypic classification.

Rodent models of abdominal wall defects (AWD) may provide insight into the pathophysiology of these conditions including gut dysfunction in gastroschisis, or pulmonary hypoplasia in exomphalos. Previously, a Scribble mutant mouse model (circletail) was reported to exhibit gastroschisis. We further characterise this AWD in Scribble knockout mice

Knowledge, experience, and potential risks of dating violence among Japanese university students: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>The Domestic Violence Prevention Act came into effect in Japan in 2001, but covers only marriage partner violence and post-divorce partner violence, and does not recognize intimate partner violence (IPV). The present study was performed to determine the experience of harassment, both toward and from an intimate partner, and recognition of harassment as IPV among Japanese university students.</p> <p>Methods</p> <p>A self-administered questionnaire survey regarding the experience of harassment involving an intimate partner was conducted as a cross-sectional study among freshman students in a prefectural capital city in Japan.</p> <p>Results</p> <p>A total of 274 students participated in the present study. About half of the subjects (both male and female students) had experience of at least one episode of harassment toward or had been the recipient of harassment from an intimate partner. However, the study participants did not recognize verbal harassment, controlling activities of an intimate partner, and unprotected sexual intercourse as violence. Experience of attending a lecture/seminar about domestic violence and dating violence did not contribute to appropriate help-seeking behavior.</p> <p>Conclusions</p> <p>An educational program regarding harassment and violence prevention and appropriate help-seeking behavior should be provided in early adolescence to avoid IPV among youth.</p

Impact of green tea on the deleterious cardiometabolic effects of 7-days unhealthy lifestyle in young healthy males.

PURPOSE: The aim of this study was to examine if catechin-rich green tea abrogates the negative effects of 7-days of physical inactivity and excessive calorie-intake on insulin homeostasis and peripheral vascular function. METHODS: Using a randomized, double-blind, crossover design, twelve healthy men (29 ± 6 yrs) underwent 7-days unhealthy lifestyle (UL), including physical inactivity (-50% steps/day) and overfeeding (+50% kcal/day). This was combined with green tea consumption (UL-tea; 3 doses/day) or placebo (UL-placebo). Before and after each intervention, we examined postprandial blood glucose and insulin (3-h after a 1,202 kcal meal) and upper and lower limb vascular function (flow-mediated dilation (FMD%)) and carotid artery reactivity (CAR%). RESULTS: UL-placebo increased postprandial glucose and insulin, while UL-tea decreased postprandial glucose and insulin (Time*Intervention interaction effects: both p  0.05) for brachial FMD%. CONCLUSION: Seven days of physical inactivity and overfeeding impair insulin homeostasis and vascular function. These effects were mitigated by a daily intake of catechin-rich green tea

Electronic gaming machine characteristics: it's the little things that count

A range of gamblers, from low-frequency social gamblers through to problem gamblers in treatment, participated in focus groups discussing the characteristics of Electronic Gaming Machines (EGMs) that they found attractive. Analyses of the resulting transcripts resulted in two groups of EGM characteristics being identified as important, one group associated with winning and one with betting. Overall, free spin features were identified in all groups as the most attractive characteristic of EGMS. Beyond that it was smaller win-related characteristics, and low-denomination machines with multiple playable lines that were associated with increased duration and intensity of gambling behaviour. The important characteristics were consistent across different levels of gamblers, with the key behavioural difference being a self-reported ‘expertise’, and ‘strategic’ approach to gambling amongst higher-frequency gamblers and problem gamblers in treatment. The key characteristics all occur frequently and result in more wins and extended gambling sessions. The patterns identified resonated with established behavioural principles, and with models describing the development of problem gambling and addictions more generally