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Monitoring the coefficient of variation using a variable sample size EWMA chart
No full textControl charts for monitoring the coefficient of variation (CV) have been receiving a lot of attention in the literature, with numerous more powerful and robust CV charts being proposed. CV charts are attracting attention due to their usefulness in monitoring processes with an inconsistent mean and a standard deviation which changes with the mean. These processes could not be monitored by conventional mean and/or standard deviation-type charts. One of the strategies to improve the performance of CV charts is by incorporating adaptive features, i.e. by varying the chart's parameters according to past sample information. Hence, this paper proposes a variable sample size (VSS) Exponentially Weighted Moving Average (EWMA) chart to monitor the CV squared (γ2), which is not available in the literature. The proposed chart allows different sample sizes to be adopted in the EWMA chart according to prior sample information. This paper shows the derivation of formulae to compute the average run length (ARL), average sample size (ASS) and expected average run length (EARL). Subsequently, an optimization algorithm to optimize the performance of the proposed chart is developed. Tables of optimal charting parameters are also provided. Next, the performance of the proposed chart is compared with five existing CV charts in the literature. The comparison shows that the proposed chart outperforms the five existing CV charts in almost all scenarios. Finally, this paper shows the implementation of the VSS EWMA-γ2chart on an actual industrial example
Associations of clothing size, adiposity and weight change with risk of postmenopausal breast cancer in the UK Women’s Cohort Study (UKWCS)
No full textOBJECTIVES: Breast cancer is associated with overweight and obesity after menopause. However, clothing size as a proxy of adiposity in predicting postmenopausal breast cancer is not widely studied. We aimed to explore the relationships between postmenopausal breast cancer risk with adipose indicators (including clothing sizes) and weight change over adulthood.
DESIGN: Prospective cohort study.
SETTING: England, Wales and Scotland.
PARTICIPANTS: 17 781 postmenopausal women from the UK Women's Cohort Study.
PRIMARY OUTCOME MEASURE: Incident cases of malignant breast cancers (International Classification of Diseases (ICD) 9 code 174 and ICD 10 code C50).
RESULTS: From 282 277 person-years follow-up, there were 946 incident breast cancer cases with an incidence rate of 3.35 per 1000 women. Body mass index (HR: 1.04; 95% CI: 1.02 to 1.07), blouse size (HR: 1.10; 1.03 to 1.18), waist circumference (HR: 1.07; 1.01 to 1.14) and skirt size (HR: 1.14;1.06 to 1.22) had positive associations with postmenopausal breast cancer after adjustment for potential confounders. Increased weight over adulthood (HR: 1.02; 1.01 to 1.03) was also associated with increased risk for postmenopausal breast cancer.
CONCLUSIONS: Blouse and skirt sizes can be used as adipose indicators in predicting postmenopausal breast cancer. Maintaining healthy body weight over adulthood is an effective measure in the prevention of postmenopausal breast cancer
Properties of Functions Involving Struve Function
No full textLet f (z) = z + ∑n=2 ∞ anzn and gp,b,c(z) = z + ∑n=2 ∞ (-c4)n-1/(3/2)n-1(k)n-1zn with p, b, c ∈ C, k = p + b+2/2 ≠ 0,-1,-2, . . . be two analytic functions in the unit disk U = (z:|z| < 1). This paper gives conditions so that the function Tp,b,c(z) = ( f * g)(z), a function associated with the Struve function, is univalent, starlike, or convex in the unit disk
A clustering approach to detect multiple outliers in linear functional relationship model for circular data
No full textOutlier detection has been used extensively in data analysis to detect anomalous observation in data. It has important applications such as in fraud detection and robust analysis, among others. In this paper, we propose a method in detecting multiple outliers in linear functional relationship model for circular variables. Using the residual values of the Caires and Wyatt model, we applied the hierarchical clustering approach. With the use of a tree diagram, we illustrate the detection of outliers graphically. A Monte Carlo simulation study is done to verify the accuracy of the proposed method. Low probability of masking and swamping effects indicate the validity of the proposed approach. Also, the illustrations to two sets of real data are given to show its practical applicability
Optimization of fed-batch fermentation processes using the Backtracking Search Algorithm
No full textFed-batch fermentation has gained attention in recent years due to its beneficial impact in the economy and productivity of bioprocesses. However, the complexity of these processes requires an expert system that involves swarm intelligence-based metaheuristics such as Artificial Algae Algorithm (AAA), Artificial Bee Colony (ABC), Covariance Matrix Adaptation Evolution Strategy (CMAES) and Differential Evolution (DE) for simulation and optimization of the feeding trajectories. DE traditionally performs better than other evolutionary algorithms and swarm intelligence techniques in optimization of fed-batch fermentation. In this work, an improved version of DE namely Backtracking Search Algorithm (BSA) has edged DE and other recent metaheuristics to emerge as superior optimization method. This is shown by the results obtained by comparing the performance of BSA, DE, CMAES, AAA and ABC in solving six fed batch fermentation case studies. BSA gave the best overall performance by showing improved solutions and more robust convergence in comparison with various metaheuristics used in this work. Also, there is a gap in the study of fed-batch application of wastewater and sewage sludge treatment. Thus, the fed batch fermentation problems in winery wastewater treatment and biogas generation from sewage sludge are investigated and reformulated for optimization
Morphometric Study of Hippocampal CA1 Pyramidal Neurons after Tualang Honey Administration
No full textTualang honey can be collected from the hives of Apis dorsata bee species on Tualang trees. Its various nutritional and curative properties could probably be due to its antioxidant effects. Subsequent to previous studies demonstrating its positive effects on spatial memory performance and hippocampal neuronal count, the current study investigated whether it has morphometric effects on the hippocampal cornu ammonis 1 (CA1) pyramidal neurons. It is important to evaluate the characteristics of hippocampal constituent neurons since this brain structure, which is primarily involved in memory processing, is most vulnerable towards oxidative stress. Male Sprague Dawley rats were force-fed five days a week for 12 consecutive weeks with 1.0ml/100g body weight of 70% Tualang honey (HON) or with 0.9% saline (SAL) as control. Nissl’s stained dorsal transverse hippocampal sections (8µm thick) of both groups were visualized under Olympus BX51 light microscope. Images were captured using Analyzer Life Science software and morphometric analysis was conducted using Image-Pro Premier 9.1 64-bit software. Only neuronal somas with clear nucleus and nucleolus were included in the morphometric analysis. Significant differences were observed between the groups for all five parameters selected (somatic area [SA], somatic perimeter [SP], somatic aspect ratio [SAR], somatic circularity index [SCI], and somatic roundness [SRo]). Values of SA and SP of HON group indicated significantly bigger sized CA1 neurons. Values of SAR, SCI and SRo, which indicated the shape of the neuronal somas, are biased towards less rounded shape. These values demonstrated HON has effects at the neuronal morphometric level
Complete genome sequence of Rhodothermaceae bacterium RA with cellulolytic and xylanolytic activities
No full textRhodothermaceae bacterium RA is a halo-thermophile isolated from a saline hot spring. Previously, the genome of this bacterium was sequenced using a HiSeq 2500 platform culminating in 91 contigs. In this report, we report on the resequencing of its complete genome using a PacBio RSII platform. The genome has a GC content of 68.3%, is 4,653,222 bp in size, and encodes 3711 genes. We are interested in understanding the carbohydrate metabolic pathway, in particular the lignocellulosic biomass degradation pathway. Strain RA harbors 57 glycosyl hydrolase (GH) genes that are affiliated with 30 families. The bacterium consists of cellulose-acting (GH 3, 5, 9, and 44) and hemicellulose-acting enzymes (GH 3, 10, and 43). A crude cell-free extract of the bacterium exhibited endoglucanase, xylanase, β-glucosidase, and β-xylosidase activities. The complete genome information coupled with biochemical assays confirms that strain RA is able to degrade cellulose and xylan. Therefore, strain RA is another excellent member of family Rhodothermaceae as a repository of novel and thermostable cellulolytic and hemicellulolytic enzymes
Macro-economic index effect on house prices in China
No full textPurpose: The purpose of this study is to estimate different data models on house prices using statistical models and the variables which are controlled by real estate policy. Design/methodology/approach: This study used several statistical techniques, such as Vector auto-regression (VAR), Johansen co-integration and variance decomposition, which aim to assess the significant effect of macroeconomic factors on Chinese house prices. Findings: The results show that land supply and other variables have negative effects on house prices. The results also indicate that financial mortgages for real estate have positive effects on house prices and the area of vacant houses as well as the area of housing sold. Research limitations/implications: This study only covers three cities in China because of limitations of data for other cities. Originality/value: This study proposes policy suggestions according to the empirical results obtained
The effects of Facebook browsing and usage intensity on impulse purchase in f-commerce
No full textDue to the rapid advancements in Web 2.0 and social media, a novel class of online social business called Facebook commerce (f-commerce) has emerged. Even though there are studies on the factors that influence Facebook browsing and usage intensity, however, there is dearth in research that examine the impacts of f-commerce browsing and usage intensity on consumers’ urge to purchase and impulse purchase. Unlike previous studies, this study examined the moderating effect of income. Since Facebook has become a phenomenon, there is a necessity to explore whether the level of f-commerce browsing and usage intensity can trigger urge to purchase and impulse purchase. Following the Stimulus-Organism-Response framework, data was collected using mall-intercept technique and analyzed with SmartPLS 3. Majority of the suggested hypotheses have been empirically validated and the research framework can explain 33.0% of variance in urge to purchase and 61.7% variance in impulse purchase. Interestingly, the finding showed no moderating effect of income. However, marital status and Internet hours were found to have moderating effects. The research findings can contribute to the online retailers, marketers and other f-commerce stakeholders in formulating their marketing strategies and policies while providing novel insight in understanding the impulse purchase behavior
Effect of the Timing of Anterior Cruciate Ligament Reconstruction on Clinical and Stability Outcomes: A Systematic Review and Meta-analysis
No full textPurpose: The purpose of this systematic review and meta-analysis was to evaluate the effect of the timing of anterior cruciate ligament (ACL) reconstruction on clinical and stability outcomes by analyzing high-quality studies that assessed timing as a primary objective. Methods: The MEDLINE, EMBASE, and Cochrane database were systematically searched. The inclusion criteria were as follows: (1) English articles, (2) noncomparative study or relevant study reporting clinical and/or stability results, and (3) timing of the ACL reconstruction as a primary objective. Study type, level of evidence, randomization method, exclusion criteria, number of cases, age, sex, timing of ACL reconstruction, follow-up, clinical outcomes, stability outcomes, and other relevant findings were recorded. Statistical analysis of the Lysholm scores and KT-1000 arthrometer measurements after early and delayed ACL reconstruction was performed using R version 3.3.1. Results: Seven articles were included in the final analysis. There were 6 randomized controlled trials and 1 Level II study. Pooled analysis was performed using only Level I studies. All studies assessed the timing of ACL reconstruction as a primary objective. The definition of early ranged broadly from 9 days to 5 months and delayed ranged from 10 weeks to >24 months, and there was an overlap of the time intervals between some studies. The standard timing of the delayed reconstruction was around 10 weeks from injury in the pooled analysis. After pooling of data, clinical result was not statistically different between groups (I2: 47%, moderate level of heterogeneity). No statistically significant difference was observed in the KT-1000 arthrometer measurements between groups (I2: 76.2%, high level of heterogeneity) either. Conclusion: This systematic review and meta-analysis performed using currently available high-quality literature provides relatively strong evidence that early ACL reconstruction results in good clinical and stability outcomes. Early ACL reconstruction results in comparable clinical and stability outcomes compared with delayed ACL reconstruction. Level of Evidence: Level II, a systematic review and meta-analysis of Level I and II studies