bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of backstepping control with CNN-based compensator for active magnetic bearing system subjected to input voltage saturation
Authors: Pati Avadh , Negi Richa 
Published: October 2018

Purpose
The stability and input voltage saturation is a common problem associated with an active magnetic bearing (AMB) system. The purpose of this paper is to design a control scheme that stabilizes the single degree of freedom AMB system and also tackle the problem of input voltage saturation in the AMB system.

Design/methodology/approach
The proposed control technique is a combination of two separate control schemes. First, the Backstepping control scheme is designed to stabilize and control the AMB system and then Chebyshev neural network (CNN)-based compensator is designed to tackle the input voltage saturation when the system control action is saturated.

Findings
The mathematical and simulation results are presented to validate the effectiveness of proposed methodology for single-degree freedom AMB system.

Originality/value
This paper introduces a CNN-based compensator with Backstepping control strategy to stabilize and tackle the problem of input voltage saturation in the 1-DOF AMB systems.
Performance evaluation in CNC turning of AA6063-T6 alloy using WASPAS approach
Authors: Sahoo Priyabrata , Satpathy Mantra Prasad , Singh Vishnu Kumar , Bandyopadhyay Asish 
Published: October 2018

PurposeSurface roughness and vibration during machining are inevitable which critically affect the product quality characteristics. This paper aims to suggest the implementation of a multi-objective optimization technique to obtain the favorable parametric conditions which lead to minimum tool vibration and surface roughness of 6063-T6 aluminum alloy in computer numerically controlled (CNC) turning.Design/methodology/approachThe case study has been accomplished according to response surface methodology RSM’s Box–Behnken design (BBD) matrix using Titanium Nitride-coated Tungsten Carbide insert in a dry environment. As the experimental results are quite nonlinear, a second-order regression model has been developed for the responses (surface roughness and tool vibration) in terms of input cutting parameters (spindle speed, feed rate and depth of cut). The goodness of fit of the models has also been verified with analysis of variance (ANOVA) results.FindingsThe significance efficacy of input parameters on surface roughness and tool vibrations has been illustrated through multi-objective overlaid 3D surface plots and contour plots. Finally, parametric optimization has been performed to get the desired response values under the umbrella of weighted aggregate sum product assessment (WASPAS) method and verified confidently with confirmatory test results.Originality/valueThe results of this study reveals that hybrid RSM with WASPAS method can be readily applicable to optimize multi-response problems in the manufacturing field with higher confidence.
An improved integrated control modeling of a high-power density interleaved non-inverting buck-boost DC-DC converter
Authors: Karimi Mohsen , Pichan Mohammad , Abrishamifar Adib , Fazeli Mehdi 
Published: October 2018

PurposeThis paper aims to propose a novel integrated control method (ICM) for high-power-density non-inverting interleaved buck-boost DC-DC converter. To achieve high power conversion by conventional single phase DC-DC converter, inductor value must be increased. This converter is not suitable for industrial and high-power applications as large inductor value will increase the inductor current ripple. Thus, two-phase non-inverting interleaved buck-boost DC-DC converter is proposed.Design/methodology/approachThe proposed ICM approach is based on the theory of integrated dynamic modeling of continuous conduction mode (CCM), discontinuous conduction mode and synchronizing parallel operation mode. In addition, it involves the output voltage controller with inner current loop (inductor current controller) to make a fair balancing between two stages. To ensure fast transient performance, proposed digital ICM is implemented based on a TMS320F28335 digital signal microprocessor.FindingsThe results verify the effectiveness of the proposed ICM algorithm to achieve high voltage regulating (under 0.01 per cent), very low inductor current ripple (for boost is 1.96 per cent, for buck is 1.1) and fair input current balance between two stages (unbalancing current less than 0.5A).Originality/valueThe proposed new ICM design procedure is developed satisfactorily to ensure fast transient response even under high load variation and the solving R right-half-plane HP zeros of the CCM. In addition, the proposed method can equally divide the input current of stages and stable different parallel operation modes with large input voltage variations.
Is Standardized Precipitation Index (SPI) a Useful Indicator to Forecast Groundwater Droughts? — Insights from a Karst Aquifer
Authors: Uddameri V. , Singaraju S. , Hernandez E.A. 
Published: October 2018

AbstractThe study sought to understand the relationships between meteorological and groundwater droughts on water levels and spring discharges in Edwards Aquifer, Texas. Standardized Precipitation Index (SPI)‐styled Standardized Groundwater Index (SGI) was used to quantify groundwater droughts. SGI time series signal was delayed and damped, while SPI was volatile. SGI values correlated well with SPI values that were observed five to eight months ago. Dynamic regression models with lagged SPI terms and autoregressive integrated moving average errors indicated a statistically significant yet weak relationship between Lag‐1 SPI and SGI. The utility of SPI for groundwater drought forecasting was minimal in this aquifer. Nonseasonal and seasonal autoregressive terms played an important role in forecasting SGI and highlighted the need for long‐term, high‐resolution monitoring to properly characterize groundwater droughts. Spring flows exhibited stronger and quicker responses to meteorological droughts than changes in storage. In aquifers with spring discharges, groundwater monitoring programs must make efforts to inventory and monitor them. Groundwater drought contingency measures can be initiated using SPI but this indicator is perhaps inappropriate to remove groundwater drought restrictions.
Carrying a logger reduces escape flight speed in a passerine bird, but relative logger mass may be a misleading measure of this flight performance detriment
Authors: Tomotani Barbara M. , Bil Wender , van der Jeugd Henk P. , Pieters Remco P. M. , Muijres Florian T. 
Published: October 2018

Abstract

The recent boost in bird migration studies following the development of various tracking devices raised awareness of how detrimental attaching devices can be for animals. Such effects can occur during migration, but also immediately post‐release if the device impairs escape flight performance and, consequently, the bird's ability to evade predators.

In this study, we investigated the effect of carrying a device on the escape flight speed and aerodynamic force production in a migratory passerine. We recorded upward‐directed escape flights of 15 male blackcaps. Each individual was tested without a tag, and when equipped with three different leg‐loop dummy tags with masses representing around 3%, 5%, and 7% of their body mass. The experiment was designed such that all individuals passed through all treatments in a randomized order.

We found that two factors affected flight speed in roughly equal amounts: first, tagged escape flights had lower flight speeds compared to the control flights, irrespective of tag mass. Second, we found an effect of the total mass, that is, the sum of the masses of the individual bird and of the tag, with heavier birds being slower. In contrast, flight speed was not correlated with relative tag mass in percentage of body mass, the metric commonly used in ethical guidelines for tag attachment. Aerodynamic flight force production also depended on total mass, with heavier birds producing higher forces. But these flight forces did not differ between flights with or without a tag.

We conclude that, when tagging birds, it is misleading to choose heavy individuals for tagging in order to minimize the tag mass as a percentage of body mass. This is particularly relevant in species for which body mass is not necessarily related to size, like migratory birds that accumulate large fat reserves. The lower escape speed in “tagged” flights could not be explained by differences in net flight force production, because these did not differ between flights with and without a tag. This suggests that the tag also affected pre‐flight take‐off dynamics, possibly due to a leg harness‐induced reduction in leg push‐off performance.
Cold tolerance of the invasive larch casebearer and implications for invasion success
Authors: Ward Samuel F. , Venette Robert C. , Aukema Brian H. 
Published: October 2018

Larch casebearer became established in North America in the late 1800s. Cold temperatures are considered a limiting factor for the insect's range, yet the cold hardiness of larch casebearer has never been quantified.We investigated (i) larval survival after acute and prolonged exposure to subzero temperatures and (ii) supercooling points (i.e. temperatures causing the onset of freezing) of overwintering and active larvae from November 2015 to April 2017.We developed models linking exposure temperatures to survival and evaluated them with larvae from field conditions. Historical minimum temperature data were used to estimate changes in survival across time at a site in northern Minnesota.The cold tolerance of larch casebearer changed significantly with season: both lower lethal temperatures and supercooling points were lowest in mid‐winter and highest in spring and autumn. For example, 50% survival was estimated after acute exposure to a mean ± SE temperature of −28.9 ± 1.77 °C in October, −40.8 ± 0.77 °C in January and −27.8 ± 1.00 °C in April.A model predicting survival using supercooling points provided conservative estimates of overwintering survival because it overestimated survival by approximately 4% and 8% in 2016 and 2017, respectively.Analysis of climate data suggested that overwintering survival could have increased significantly over the previous half century.
Variance component estimators OPE, NOPE and AOPE in linear mixed effects models
Authors: Ghosh Subir , Guo Li , Peng Luyao 
Published: October 2018

SummaryOptimum variance component estimation methods that yield uniformly minimum variance quadratic unbiased estimators for a full dataset are often difficult or impossible to implement. In this paper we propose an estimator which is near optimal under some distributional assumptions that can be made without specifying an exact functional form. This estimator has an exact closed form expression. An average optimum estimator, which can be used when optimum estimators exist for subsets of the data, is also proposed. Performance comparisons of the proposed estimators are made individually with other popular estimators using simulated data. A performance comparison of the average optimum estimator is made under four constraints on the variance components. A real dataset is analysed using the proposed estimators. The robustness properties of the proposed estimators, in comparison with the other estimators, including the method of moments, are also investigated, using data simulated from a skew normal distribution. The average optimum estimator is strongly robust and far superior for estimating one of the variance components, as demonstrated by making comparisons with other methods. These comparisons are based on bias, mean squared error, and mean absolute deviation. The average estimator is moderately robust in respect of the estimation of the other variance components.
Physicians' Interactions with Peers: Empathic Accuracy during Shift Handovers on Intensive‐Care Units
Authors: Klumb Petra L. , Wicki Chantal , Rauers Antje 
Published: October 2018

BackgroundWe investigated how accurately physicians judge colleagues' states during shift handovers on intensive‐care units, the role of physician characteristics, and how accuracy is related to handover partners' satisfaction.MethodsUsing mobile phones, we assessed momentary judgements during N = 272 shift handovers by 36 physicians of five Swiss clinics. Physicians rated their own and their partner's affective states. We calculated the covariation of the perceiver's judgements of the partner's affect with the partner's self‐reported affect and the perceiver's own self‐reported affect. We then examined the moderation of these covariations by physicians' roles and experience.ResultsOverall, resident physicians were moderately successful in taking their counterparts' perspective: Perceiver's ratings of partner's affect and the latter's self‐ratings were significantly related. Associations between perceivers' ratings of their own and their partner's affect were also evident. None of the effects varied as a function of physicians' roles. There was an unexpected effect of job experience; physicians with more experience were more likely to project their own affect into the rating of partner's affect. Physicians' accuracy in judging the partner's tense arousal was related to the partner's satisfaction with the social interaction. This effect may have been mainly driven by instances in which low tension was accurately judged, however.
Prevalence ofCYP2D6*4 1934G/A polymorphism in Western IndianHIVpatients
Authors: Singh HariOm , Lata Sonam , Gangakhedkar Raman R. 
Published: October 2018

HepaticCYP2D6enzyme metabolizes antiretroviral drugs (ARVs) including nevirapine. Polymorphism inCYP2D6gene affects drug metabolism and displays distinctive phenotypes in the population. Hence, we investigated the prevalence ofCYP2D6*41934G/A polymorphism in a total of 165HIVpatients that include 34 with and 131 without hepatotoxicity and 160 unrelated healthy controls by thePCR‐RFLPmethod. The prevalence ofCYP2D6*41934AAgenotype was higher in totalHIVpatients as compared to healthy controls (1.81% vs 0.6%,OR = 2.86). Similarly,CYP2D6*41934AAgenotype was much more prevalent inHIVpatients without hepatotoxicity as compared to healthy controls (2.3% vs 0.6%,OR = 2.87). Likewise,CYP2D6*41934AAgenotype was predominant in advancedHIVdisease stage as compared to healthy controls (3.8% vs 0.6%,OR = 6.15).CYP2D6*41934GAgenotype was distributed higher inHIVpatients taking tobacco and nevirapine as compared to non‐users (23.3% vs 19.3%,OR = 1.21, 21.0% vs 16.7%,OR = 1.2). Likewise,CYP2D6*41934GAgenotype was overrepresented in patients with hepatotoxicity taking alcohol + nevirapine as compared to alcohol non‐users + nevirapine users (20.00% vs 16.67%,OR = 1.25). Thus, there was no significant difference in genotype or allele frequencies ofCYP2D6*41934G/A polymorphism between the patients with hepatotoxicity and those without or healthy controls.
Bartonella quintana, past, present, and future of the scourge of World War I
Authors: Ruiz Joaquim 
Published: October 2018

During World War I, a mysterious new disease affected soldiers on both sides of battle field. The first reports described a relapsing fever of unknown origin with body lice being suggested as the vector. The outbreak affected >1 000 000 people, mostly soldiers fighting in front‐line trenches. Shortly afterward, the illness was known as Trench fever, of which the causal infectious agent is currently classified as Bartonella quintana.
Evaluation of the venous drainage pattern of the splenic flexure by preoperative three‐dimensional computed tomography
Authors: Arimoto Akira , Matsuda Takeru , Hasegawa Hiroshi , Yamashita Kimihiro , Nakamura Tetsu , Sumi Yasuo , Suzuki Satoshi , Kakeji Yoshihiro 
Published: October 2018

AbstractIntroductionAnatomical evaluation of the splenic flexure vein is essential for complete mesocolic excision with central vascular ligation when treating patients with splenic flexure cancer. Although there have been several studies relating to the arterial branches of the splenic flexure, very limited data are available regarding the variation in venous anatomy in this region.MethodsSixty‐six patients with colorectal cancer who underwent preoperative 3‐D CT between April 2016 and April 2017 were included in this retrospective study. The pattern of the venous drainage of the splenic flexure and its association with the inferior border of the pancreas were evaluated.ResultsThe inferior mesenteric vein flowed into the splenic vein in 32 patients (48.5%), into the superior mesenteric vein in 27 patients (40.9%), and into the confluence of splenic vein and superior mesenteric vein in 7 patients (10.6%). The splenic flexure vein joined the inferior mesenteric vein in 62 patients (93.9%), the splenic vein in 2 patients (3.0%), and the middle colic vein in 2 patients (3.0%). The splenic flexure vein flowed into the inferior mesenteric vein below the level of the inferior border of the pancreas in 58 patients (90.6%) and above it in 4 patients (6.3%).ConclusionPreoperative evaluation of the venous pattern of the splenic flexure on 3‐D CT is useful before complete mesocolic excision with central vascular ligation to avoid intraoperative bleeding during splenic flexure cancer surgery.
Significance of CCN2 expression in bovine preimplantation development
Authors: Akizawa Hiroki , Yanagawa Yojiro , Nagano Masashi , Bai Hanako , Takahashi Masashi , Kawahara Manabu 
Published: October 2018

AbstractIn mammalian preimplantation development, the first cell lineage segregation occurs during the blastocyst stage, when the inner cell mass and trophectoderm (TE) differentiate. Species‐specific analyses are essential to elucidate the molecular mechanisms that underlie this process, since they differ between various species. We previously showed that the reciprocal regulation of CCN2 and TEAD4 is required for proper TE differentiation in bovine blastocysts; however, the function of CCN2 during early embryogenesis has remained otherwise elusive. The present study assessed the spatiotemporal expression dynamics of CCN2 in bovine embryos, and evaluated how changes to CCN2 expression (using a CCN2 knockdown (KD) blastocyst model) regulate the expression of pluripotency‐related genes such as OCT4 and NANOG. The conducted quantitative PCR analysis revealed that CCN2 mRNA was expressed in bovine oocytes (at the metaphase stage of their second meiosis) and embryos. Similarly, immunostaining detected both cytoplasmic and nuclear CCN2 at all analyzed oocyte and embryonic stages. Finally, both OCT4 and NANOG expression levels were shown to be significantly reduced in CCN2 KD blastocysts. Together, these results demonstrate that bovine CCN2 exhibits unique expression patterns during preimplantation development, and is required for the proper expression of key regulatory genes in bovine blastocysts.
Can women in labor give informed consent to epidural analgesia?
Authors: Wada Kyoko , Charland Louis C. , Bellingham Geoff 
Published: October 2018

AbstractThere are reasons to believe that decision‐making capacity (mental competence) of women in labor may be compromised in relation to giving informed consent to epidural analgesia. Not only severe labor pain, but also stress, anxiety, and premedication of analgesics such as opioids, may influence women’s decisional capacity. Decision‐making capacity is a complex construct involving cognitive and emotional components which cannot be reduced to ‘understanding’ alone. A systematic literature search identified a total of 20 empirical studies focused on women’s decision‐making about epidural analgesia for labor pain. Our review of these studies suggests that empirical evidence to date is insufficient to determine whether women undergoing labor are capable of consenting to epidural analgesia. Given such uncertainties, sufficient information about pain management should be provided as part of prenatal education and the consent process must be carefully conducted to enhance women’s autonomy. To fill in the significant gap in clinical knowledge about laboring women’s decision‐making capacity, well‐designed prospective and retrospective studies may be required.
Instrumental Variable Based Estimation Under the Semiparametric Accelerated Failure Time Model
Authors: Huling Jared D. , Yu Menggang , O'Malley A. James 
Published: October 2018

AbstractRandomized controlled trials are the gold standard for estimating causal effects of treatments or interventions, but in many cases are too costly, too difficult, or even unethical to conduct. Hence, many pressing medical questions can only be investigated using observational studies. However, direct statistical modeling of observational data can result in biased estimates of treatment effects due to unmeasured confounding. In certain cases, instrumental variable based techniques can be used to remove such biases. These techniques are indeed widely studied and used in econometrics under parametric outcome models, however limited works have focused on the utilization of instrumental variables in survival analysis, where semiparametric models are often necessary. The additional challenge in analyzing survival data is the presence of censoring. In this paper, we introduce an instrumental variable method that relaxes the strong assumptions of previous works and provides consistent estimation of the causal effect of a treatment on a survival outcome. We demonstrate the efficacy of our method in various simulated settings and an analysis of Medicare enrollment data comparing two prevalent surgical procedures for abdominal aortic aneurysm from an observational study.
Longitudinal and Time-to-Drop-Out Joint Models Can Lead to Seriously Biased Estimates When the Drop-Out Mechanism is at Random
Authors: Thomadakis Christos , Meligkotsidou Loukia , Pantazis Nikos , Touloumi Giota 
Published: October 2018

Abstract
Missing data are common in longitudinal studies. Likelihood-based methods ignoring the missingness mechanism are unbiased provided missingness is at random (MAR); under not-at-random missingness (MNAR), joint modeling is commonly used, often as part of sensitivity analyses. In our motivating example of modeling CD4 count trajectories during untreated HIV infection, CD4 counts are mainly censored due to treatment initiation, with the nature of this mechanism remaining debatable. Here, we evaluate the bias in the disease progression marker's change over time (slope) of a specific class of joint models, termed shared-random-effects-models (SREMs), under MAR drop-out and propose an alternative SREM model. Our proposed model relates drop-out to both the observed marker's data and the corresponding random effects, in contrast to most SREMs, which assume that the marker and the drop-out processes are independent given the random effects. We analytically calculate the asymptotic bias in two SREMs under specific MAR drop-out mechanisms, showing that the bias in marker's slope increases as the drop-out probability increases. The performance of the proposed model, and other commonly used SREMs, is evaluated under specific MAR and MNAR scenarios through simulation studies. Under MAR, the proposed model yields nearly unbiased slope estimates, whereas the other SREMs yield seriously biased estimates. Under MNAR, the proposed model estimates are approximately unbiased, whereas those from the other SREMs are moderately to heavily biased, depending on the parameterization used. The examined models are also fitted to real data and results are compared/discussed in the light of our analytical and simulation-based findings.