Signal quality measures for unsupervised blood pressure measurement

Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure differences between the result obtained from the algorithm and the RS. 90% of the actual noise contaminated signals were correctly identified, and a sample-wise accuracy, sensitivity and specificity of 97.0%, 80.61% and 98.16%, respectively, were obtained from 100 pooled signals. The mean systolic and diastolic differences were 0.37 ± 3.31 and 3.10 ± 5.46 mmHg, respectively, when the artifact detection algorithm was utilized, with the algorithm correctly determined if the signal was clean enough to attempt an estimation of systolic or diastolic pressures in 93% of blood pressure measurements

PENGARUH AUDIT TENURE DAN REPUTASI KAP TERHADAP PENERBITAN OPINI GOING CONCERN (Studi empiris pada perusahaan manufaktur yang terdaftar di BEI tahun 2009 -2011)

The purpose of this study is to examine the impact audit tenure and audit firm reputation on issued going concern opinion while mandatory audit firm is going. Many factor can affect going concern opinion both positively and negatively. Previous studies on going concern opinion found differrent results, so it need to be repeated to verify previous research on going concern opinion. Samples were gathered from audit reports of 128 manufacturing companies that were listed in Indonesia Stock Exchange (IDX) during 2009-2011 reporting period. Research variables used were audit tenure, audit firm reputation, and going concern audit opinion. By using logistic regression analysis with SPSS 20 application, this study tried to examine the influence of the audit tenure and audit firm reputation on issued going concern opinion. The results were as follows : (1) audit tenure does not significantly affect on issued going concern opinion, (2) audit firm reputation significantly affect on issued going concern opinion

Analyzing Group by Time Effects in Longitudinal Two-Group Randomized Trial Designs With Missing Data

We investigated bias, sampling variability, Type I error and power of nine approaches for testing the group by time interaction in a repeated measures design under three types of missing data mechanisms. One procedure due to Overall, Ahn, Shivakumar, and Kalburgi (1999) performed reasonably well over a range of conditions

Discontinuous Galerkin method for the spherically reduced BSSN system with second-order operators

We present a high-order accurate discontinuous Galerkin method for evolving the spherically-reduced Baumgarte-Shapiro-Shibata-Nakamura (BSSN) system expressed in terms of second-order spatial operators. Our multi-domain method achieves global spectral accuracy and long-time stability on short computational domains. We discuss in detail both our scheme for the BSSN system and its implementation. After a theoretical and computational verification of the proposed scheme, we conclude with a brief discussion of issues likely to arise when one considers the full BSSN system.Comment: 35 pages, 6 figures, 1 table, uses revtex4. Revised in response to referee's repor

Social networks, rice value chain participation and market performance of smallholder farmers in Ghana

This paper examines the impact of rice value chain participation and social networks on smallholder farmers' market performance outcomes (paddy price, quantity of paddy traded, and net returns), using data from a recent survey of 458 smallholder rice farmers in northern Ghana. We employed a treatment effects model to account for potential selection bias associated with observable and unobservable factors. The empirical results reveal that smallholder farmers' participation in a rice value chain is associated with increased paddy price, quantity traded, and net returns. We also find that value chain participation decisions and market performance are positively and significantly influenced by social networks. The empirical results also suggest that sex, farm size, mobile phone ownership, and access to credit significantly increase paddy prices, quantity traded, and net returns of smallholder rice farmers in the value chain

Preliminary Testing for Normality: Is This a Good Practice?

Normality is a distributional requirement of classical test statistics. In order for the test statistic to provide valid results leading to sound and reliable conclusions this requirement must be satisfied. In the not too distant past, it was claimed that violations of normality would not likely jeopardize scientific findings (See Hsu & Feldt, 1969; Lunney, 1970). Recent revelations suggest otherwise (See e.g., Micceri, 1989; Keselman, Huberty, Lix et al., 1998; Erceg-Hurn, Wilcox, & Keselman, 2013; Wilcox and Keselman, 2003; Wilcox, 2012a, b). Unfortunately the data obtained in psychological investigations rarely, if ever, meet the requirement of normally distributed data (Micceri, 1989; Wilcox, 2012a, b). Consequently, it could be the case that the results from many of the investigations conducted in psychology provide invalid results. Accordingly, authors recommend that researchers attempt to assess the validity of assuming data are normal in form prior to conducting a test of significance (Erceg-Hurn, et al., 2013; Keselman, et al., 1998). Present evidence suggests that a popular fit-statistic, the Kolmogorov-Smirnov test does a poor job of evaluating whether data are normal. Our investigation based on this statistic and other fit-statistics provides a more favorable picture of preliminary testing for normality

Cyclopentyl Trisilanol Silsesquioxanes – Modified Natural Rubber (CpSSQ(OH)3 – ENR-50) Nanocomposite In The Presence Of Tin (II) Chloride Dihydrate

A nanocomposite comprising cyclopentyl trisilanol silsesquioxanes (CpSSQ(OH)3) and 50% epoxidized natural rubber (ENR-50) was prepared at reflux temperature with Tin (II) chloride dihydrate (SnCl2.2H2O) as catalyst. SnCl2.2H2O was found to be an affective catalyst to promote ring opening in ENR-50 and tailored it to CpSSQ(OH)3 via chemical reaction. The generation of carbonyl functional groups arising from epoxide ring opening can be clearly seen in FTIR spectra. 1H and 29Si NMR analyses further proved that the incorporation of CpSSQ(OH)3 in ENR-50 occured. TGA studies showed a degradation temperature with 10% weight decreased and DSC thermogram indicates a single Tg. Single peak in XRD diffractogram at 2-Theta angle further confirmed the surface modification