A parametric bootstrap approach for two-way ANOVA in presence of possible interactions with unequal variances

Bootstrap tests for simultaneous monotone ordering of effects in a two-way ANOVA

In a two-way additive analysis of variance (ANOVA) model, we consider the problem of testing for homogeneity of both row and column effects against their simultaneous ordering. The error variances are assumed to be heterogeneous with unbalanced samples in each cell. Two simultaneous test procedures are developed-the first one using the likelihood ratio test (LRT) statistics of two independent hypotheses and another based on the consecutive pairwise differences of estimators of effects. The parametric bootstrap (PB) approach is used to find critical points of both the tests and the asymptotic accuracy of the bootstrap is established. An extensive simulation study shows that the proposed tests achieve the nominal size and have very good power performance. The robustness of the tests is also analyzed under deviation from normality. An "R" package is developed and shared on "GitHub" for ease of implementation of users. The proposed tests are illustrated using a real data set on the mortality due to alcoholic liver disease and it is shown that age and gender have a significant impact on the increasing incidence of mortality.

Driver-Automated Vehicle Interaction in Mixed Traffic: Types of Interaction and Drivers' Driving Styles

OBJECTIVE

This study investigated drivers' subjective feelings and decision making in mixed traffic by quantifying driver's driving style and type of interaction.

BACKGROUND

Human-driven vehicles (HVs) will share the road with automated vehicles (AVs) in mixed traffic. Previous studies focused on simulating the impacts of AVs on traffic flow, investigating car-following situations, and using simulation analysis lacking experimental tests of human drivers.

METHOD

Thirty-six drivers were classified into three driver groups (aggressive, moderate, and defensive drivers) and experienced HV-AV interaction and HV-HV interaction in a supervised web-based experiment. Drivers' subjective feelings and decision making were collected via questionnaires.

RESULTS

Results revealed that aggressive and moderate drivers felt significantly more anxious, less comfortable, and were more likely to behave aggressively in HV-AV interaction than in HV-HV interaction. Aggressive drivers were also more likely to take advantage of AVs on the road. In contrast, no such differences were found for defensive drivers indicating they were not significantly influenced by the type of vehicles with which they were interacting.

CONCLUSION

Driving style and type of interaction significantly influenced drivers' subjective feelings and decision making in mixed traffic. This study brought insights into how human drivers perceive and interact with AVs and HVs on the road and how human drivers take advantage of AVs.

APPLICATION

This study provided a foundation for developing guidelines for mixed transportation systems to improve driver safety and user experience.

Investigating the impact of smoking habits through photoplethysmography analysis

Smoking is widely recognized as a significant risk factor in the progression of arterial stiffness and cardiovascular diseases. Valuable information related to cardiac arrhythmias and heart function can be obtained by analyzing biosignals such as the electrocardiogram (ECG) and the photoplethysmogram (PPG). The PPG signal is a non-invasive optical technique that can be used to evaluate the changes in blood volume, and thus it can be linked to the health of the vascular system.Objective. In this study, the impact of three smoking habits-cigarettes, shisha, and electronic cigarettes (e-cigarettes)-on the features of the PPG signal were investigated.Approach. The PPG signals are measured for 45 healthy smokers before, during, and after the smoking session and then processed to extract the morphological features. Quantitative statistical techniques were used to analyze the PPG features and provide the most significant features of the three smoking habits. The impact of smoking is observed through significant changes in the features of the PPG signal, indicating blood volume instability.Main results. The results revealed that the three smoking habits influence the characteristics of the PPG signal significantly, which presentseven after 15 min of smoking. Among them, shisha has the greatest impact on PPG features, particularly on heart rate, systolic time, augmentation index, and peak pulse interval change. In contrast, e-cigarettes have the least effect on PPG features. Interestingly, smoking electronic cigarettes, which many participants use as a substitute for traditional cigarettes when attempting to quit smoking, has nearly a comparable effect to regular smoking.Significance. The findings suggest that individuals who smoke shisha are more likely to develop cardiovascular diseases at an earlier age compared to those who have other smoking habits. Understanding the variations in the PPG signal caused by smoking can aid in the early detection of cardiovascular disorders and provide insight into cardiac conditions. This ultimately contributes to the prevention of the development of cardiovascular diseases and the development of a health screening system.

Multiple comparisons of treatment against control under unequal variances using parametric bootstrap

In one-way analysis of variance models, performing simultaneous multiple comparisons of treatment groups with a control group may be of interest. Dunnett's test is used to test such differences and assumes equal variances of the response variable for each group. This assumption is not always met even after transformation. A parametric bootstrap (PB) method is developed here for comparing multiple treatment group means against the control group with unequal variances and unbalanced data. In simulation studies, the proposed method outperformed Dunnett's test in controlling the type I error under various settings, particularly when data have heteroscedastic variance and unbalanced design. Simulations show that power is often lower for the PB method than for Dunnett's test under equal variance, balanced data, or smaller sample size, but similar to or higher than for Dunnett's test with unequal variance, unbalanced data and larger sample size. The method is applied to a dataset concerning isotope levels found in elephant tusks from various geographical areas. These data have very unbalanced group sizes and unequal variances. This example illustrates that the PB method is easy to implement and avoids the need for transforming data to meet the equal variance assumption, simplifying interpretation of results.

Response Time Modulates the Relationship Between Implicit Learning and Motor Ability in Children With and Without Autism Spectrum Disorders: A Preliminary Study

Difficulty with implicit learning plays an important role in the symptomology of autism spectrum disorder (ASD). However, findings in motor learning are inconsistent. This study evaluated implicit sequence learning and its relationship with motor ability in children with and without ASD. We adopted a classic serial reaction time task with a retention task and three awareness tests. The Movement Assessment Battery for Children was administered to assess children's motor ability. Significant learning differences between children with and without ASD were only found in retention but not immediately after the serial reaction time task. These findings suggest that the impaired implicit learning in ASD is characterized as impaired consolidation where the relatively permanent changes are missing. Exploratory moderation analyses revealed a significant relationship between implicit learning and motor ability for individuals with faster response time. We argue the importance of response speed for optimal learning and should be weighted more for future intervention in children with ASD.

Targeting the interaction of GABAB receptors with CaMKII with an interfering peptide restores receptor expression after cerebral ischemia and inhibits progressive neuronal death in mouse brain cells and slices

Cerebral ischemia is the leading cause for long-term disability and mortality in adults due to massive neuronal death. Currently, there is no pharmacological treatment available to limit progressive neuronal death after stroke. A major mechanism causing ischemia-induced neuronal death is the excessive release of glutamate and the associated overexcitation of neurons (excitotoxicity). Normally, GABA_B receptors control neuronal excitability in the brain via prolonged inhibition. However, excitotoxic conditions rapidly downregulate GABA_B receptors via a CaMKII-mediated mechanism and thereby diminish adequate inhibition that could counteract neuronal overexcitation and neuronal death. To prevent the deleterious downregulation of GABA_B receptors, we developed a cell-penetrating synthetic peptide (R1-Pep) that inhibits the interaction of GABA_B receptors with CaMKII. Administration of this peptide to cultured cortical neurons exposed to excitotoxic conditions restored cell surface expression and function of GABA_B receptors. R1-Pep did not affect CaMKII expression or activity but prevented its T286 autophosphorylation that renders it autonomously and persistently active. Moreover, R1-Pep counteracted the aberrant downregulation of G protein-coupled inwardly rectifying K⁺ channels and the upregulation of N-type voltage-gated Ca²⁺ channels, the main effectors of GABA_B receptors. The restoration of GABA_B receptors activated the Akt survival pathway and inhibited excitotoxic neuronal death with a wide time window in cultured neurons. Restoration of GABA_B receptors and neuroprotective activity of R1-Pep was verified by using brain slices prepared from mice after middle cerebral artery occlusion (MCAO). Treatment with R1-Pep restored normal GABA_B receptor expression and GABA receptor-mediated K⁺ channel currents. This reduced MCAO-induced neuronal excitability and inhibited neuronal death. These results support the hypothesis that restoration of GABA_B receptor expression under excitatory conditions provides neuroprotection and might be the basis for the development of a selective intervention to inhibit progressive neuronal death after ischemic stroke.

Asymptotic-based bootstrap approach for matched pairs with missingness in a single arm

The issue of missing values is an arising difficulty when dealing with paired data. Several test procedures are developed in the literature to tackle this problem. Some of them are even robust under deviations and control type-I error quite accurately. However, most of these methods are not applicable when missing values are present only in a single arm. For this case, we provide asymptotic correct resampling tests that are robust under heteroskedasticity and skewed distributions. The tests are based on a meaningful restructuring of all observed information in quadratic form-type test statistics. An extensive simulation study is conducted exemplifying the tests for finite sample sizes under different missingness mechanisms. In addition, illustrative data examples based on real life studies are analyzed.

Gestational Women's Perceptions About the Harms of Cigarette and E-Cigarette Use During Pregnancy

OBJECTIVES

The purpose of this study was to examine differences between perceived harm of cigarette and electronic cigarette (e-cigarette) use while pregnant and differences between healthcare providers' communication about these products during pregnancy.

METHODS

A convenience sample of gestational women (n = 218; ages 18-45) living in the US completed an online survey between May and December 2017. Participants reported perceived likelihood of adverse health outcomes (e.g., low birth weight, sudden infant death syndrome) among infants/children born to mothers who used cigarettes/e-cigarettes. T-tests and two-way ANOVAs examined differences between risk perceptions of using cigarettes/e-cigarettes while pregnant based on pregnancy status (previously pregnant, currently pregnant, future pregnant). Chi-square analyses examined differences between healthcare provider communication about cigarette/e-cigarette use during pregnancy.

RESULTS

Overall, participants believed adverse health outcomes were significantly more likely to be caused by maternal use of cigarettes than e-cigarettes. Participants who planned to be pregnant reported higher endorsement that smoking combustible cigarettes would cause a miscarriage (p < .05) or increased blood pressure (p < .05) for a child than currently pregnant participants. Participants reported healthcare providers asked about (p < .05), advised them not to use (p < .001), and talked to them about health effects of smoking combustible cigarettes while pregnant (p < .001) significantly more than e-cigarettes.

CONCLUSIONS FOR PRACTICE

Healthcare providers working with pregnant women should perform the 5As behavioral intervention method to provide pregnant women with tobacco cessation care. They should also discuss the absolute harm nicotine exposure (via cigarettes or e-cigarettes) can have on fetal health and development.

Evaluation of ammonia and odour emissions from animal slurry and digestate storage in the Po Valley (Italy)

Ammonia and odour emissions from one lagoon (Lagoon 1: pig slurry) and three tanks (Tank 2: cow slurry; Tank 3: digestate from pig slurry and energy crops; Tank 4: digestate from pig and cow slurries plus energy crop) used for slurry storage were sampled for two years (2015-2017) in livestock farms that differed for animal breeding and manure management (anaerobic digestion). On average, the ammonia emission rate (AER) was higher for Tank 3 (AER of 30.68 ± 28.1 g N-NH₃ m^-2 d^-1) than for Lagoon 1 and Tank 2 and 4, i.e. 9.29 ± 14.89 gN-NH₃ m^-2 d^-1, 9.38 ± 13.75 g N-NH₃ m^-2 d^-1, 15.74 ± 21.91 g N-NH₃ m^-2 d^-1, respectively. PLS regression analysis (R² = 0.544; R²_Adj. = 0.484) indicated that temperature was the main predictor of ammonia emitted, followed by concentration in the slurry of total ammonia and the relative percentage of volatile solids (VS). On the other hand, PLS analysis (R² = 0.529, R²adj. = 0.417) indicated that odour emissions from animal slurry storages depended similarly upon total solids and VS (both referred to fresh weight) slurry contents, TAN/TKN ratio and degrees of biological stability (measured by anaerobic biogas potential - ABP), resulting in the Specific Odours Emission Rates (SOER) of 12,124 ± 7,914 and 35,207 ± 41,706 OUE m^-2 h^-1, 65,430 ± 45,360 and 43,971 ± 53,350 OUE m^-2 h^-1, for Lagoon 1 and Tanks 2, 3 and 4. These results suggest covering the tanks to limit both ammonia and odour emissions.

Brief Report: Does Social Functioning Moderate the Motor Outcomes of a Physical Activity Program for Children with Autism Spectrum Disorders-A Pilot Study

Several recent studies revealed that physical activity programs that focus on fundamental motor skills could enhance both motor and social performance. The purpose of this pilot was to explore whether the social impairment of Autistic Spectrum Disorders (ASD) moderated the motor outcomes of a physical activity program. Nine children with ASD attended a 2-week program that adopted the Classroom Pivotal Response Teaching. Significant improvements on motor skills were found in all participants. Furthermore, children with more social impairment demonstrated greater motor improvement in comparison to those with less social problems. Findings suggest the importance of social factors on the outcomes of physical activity programs and the interplays between social and motor domains in ASD interventions.

Archetypes of human cognition defined by time preference for reward and their brain correlates: An evolutionary trade-off approach

Biological systems carry out multiple tasks in their lifetime, which, in the course of evolution, may lead to trade-offs. In fact phenotypes (different species, individuals within a species, circuits, bacteria, proteins, etc.) cannot be optimal at all tasks, and, according to Pareto optimality theory, lay into a well-defined geometrical distribution (polygons and/or polyhedrons) in the space of traits. The vertices of this distribution contain archetypes, namely phenotypes that are specialists at one of the tasks, whereas phenotypes toward the center of the geometrical distribution show average performance across tasks. We applied this theory to the variability of cognitive and behavioral scores measured in 1206 individuals from the Human Connectome Project. Among all possible combinations of pairs of traits, we found the best fit to Pareto optimality when individuals were plotted in the trait-space of time preferences for reward, evaluated with the Delay Discounting Task (DDT). The DDT measures subjects' preference in choosing either immediate smaller rewards or delayed larger rewards. Time preference for reward was described by a triangular distribution in which each of the three vertices included individuals who used a particular strategy to discount reward. These archetypes accounted for variability on many cognitive, personality, and socioeconomic status variables, as well as differences in brain structure and functional connectivity, with only a weak influence of genetics. In summary, time preference for reward reflects a core variable that biases human phenotypes via natural and cultural selection.

Testing Mean Differences among Groups: Multivariate and Repeated Measures Analysis with Minimal Assumptions

To date, there is a lack of satisfactory inferential techniques for the analysis of multivariate data in factorial designs, when only minimal assumptions on the data can be made. Presently available methods are limited to very particular study designs or assume either multivariate normality or equal covariance matrices across groups, or they do not allow for an assessment of the interaction effects across within-subjects and between-subjects variables. We propose and methodologically validate a parametric bootstrap approach that does not suffer from any of the above limitations, and thus provides a rather general and comprehensive methodological route to inference for multivariate and repeated measures data. As an example application, we consider data from two different Alzheimer's disease (AD) examination modalities that may be used for precise and early diagnosis, namely, single-photon emission computed tomography (SPECT) and electroencephalogram (EEG). These data violate the assumptions of classical multivariate methods, and indeed classical methods would not have yielded the same conclusions with regards to some of the factors involved.

Localized Delivery of Cl-Amidine From Electrospun Polydioxanone Templates to Regulate Acute Neutrophil NETosis: A Preliminary Evaluation of the PAD4 Inhibitor for Tissue Engineering

Upon interaction, neutrophils can potentially release neutrophil extracellular traps (NETs) on the surface of an implanted electrospun template, which may be a significant preconditioning event for implantable biomaterials of yet unknown consequences. In this study, we investigated the potential of polydioxanone templates as a delivery vehicle for Cl-amidine, an inhibitor of peptidyl arginase deiminase 4 (PAD4), and if drug elution could attenuate PAD4-mediated NETosis in the vicinity of implanted templates. Electrospun polydioxanone templates were fabricated with distinct architectures, small diameter (0.4 μm) or large diameter (1.8 μm) fibers, and incorporated with 0-5 mg/mL Cl-amidine to examine dose-dependent effects. Acute neutrophil-template interactions were evaluated in vitro with freshly isolated human neutrophils and in vivo with a rat subcutaneous implant model. The in vitro results suggest large diameter templates with 0 mg/mL Cl-amidine significantly attenuate NETosis compared to small diameter templates. As the drug concentration increased, NETosis was significantly decreased on small diameter templates in a dose-dependent manner. The opposite was observed for large diameter templates, indicating multiple mechanisms of NETosis may be regulating neutrophil template preconditioning. Similar results were observed in vivo, verifying local NETosis inhibition by Cl-amidine eluting templates in a physiological environment. Importantly, large diameter templates with Cl-amidine enhanced neutrophil invasion and survival, supporting the potential for long-term modulation of tissue integration and regeneration. This preliminary study demonstrates a novel delivery vehicle for Cl-amidine that can be used to regulate acute NETosis as the potential critical link between the innate immune response, inflammation, and template-guided tissue regeneration.

Study of the ambient air metallic elements Cr, Cu, Zn, Cd and Pb at HAF sampling sites

This study characterized diurnal variations in the compositions of total suspended particulates (TSP) and dry deposits of particulates from ambient air, and the metallic elements that are contained in them at harbor, airport and farmland (HAF) sampling sites from August, 2013 to July, 2014. Two-way ANOVA of the amounts of metallic elements in the TSP and dry deposits was carried out in all four seasons at the HAF sampling sites. The metallic elements Cr and Cu originated in local emission sources at the airport. Metallic elements Zn and Pb originated in local emission sources at the harbor. Finally, metallic element Cd originated in local emissions form farmland. The following results were also obtained. (1) The metallic composition of the TSP differed significantly from that of the dry deposits in all four seasons at the harbor and farmland sampling sites, but not at the airport sampling site. (2) High correlations coefficients were found between the amounts of metallic elements Cr and Cu in the TSP and those in the dry deposits at the airport sampling site. (3) Pb was present in the TSP and the dry deposits at the harbor sampling site.

Seasonal variations and sources study by way of back trajectories and ANOVA for ambient air pollutants (particulates and metallic elements) within a mixed area at Longjing, central Taiwan: 1-year observation

This study measured the concentrations of particulates and metallic elements in ambient air by using PS-1 sampler (TSP) at Longjing area. And this study focuses on the collection of ambient air particulates, metallic elements, particulate-bound mercury Hg(p), concentrations. In addition, the sources of ambient pollutants by way of back trajectory analysis are found. Moreover, test mean concentration variance differences for metallic elements (PM, Hg(p), Mn, Fe, Zn, Cr, Cu, and Pb) among the four seasons (spring, summer, autumn and winter) through ANOVA are calculated. The result indicates that the average highest particulate concentration occurred in winter season, and the order was winter > spring > autumn > summer, and the mostly highest average metallic element (Mn, Fe, Zn, Cr, Cu, Pb) concentrations occurred in autumn. Moreover, the mostly average lowest metallic element concentrations occurred in summer. In addition, the above results of backward trajectories that the major particulate pollutants parcel mainly come from northeastern Taiwan. Moreover, when comparing the results of the first half year to that of the second half year, the they indicated that all metallic elements displayed significant differences in concentrations except those of Hg(p), Mn, Fe, Zn. Finally, metallic element Hg(p) is the only one which showed no significant concentration difference from either seasonal variations or half-year observations.

Effectiveness and Adoption of a Drawing-to-Learn Study Tool for Recall and Problem Solving: Minute Sketches with Folded Lists

Drawing by learners can be an effective way to develop memory and generate visual models for higher-order skills in biology, but students are often reluctant to adopt drawing as a study method. We designed a nonclassroom intervention that instructed introductory biology college students in a drawing method, minute sketches in folded lists (MSFL), and allowed them to self-assess their recall and problem solving, first in a simple recall task involving non-European alphabets and later using unfamiliar biology content. In two preliminary ex situ experiments, students had greater recall on the simple learning task, non-European alphabets with associated phonetic sounds, using MSFL in comparison with a preferred method, visual review (VR). In the intervention, students studying using MSFL and VR had ∼50-80% greater recall of content studied with MSFL and, in a subset of trials, better performance on problem-solving tasks on biology content. Eight months after beginning the intervention, participants had shifted self-reported use of drawing from 2% to 20% of study time. For a small subset of participants, MSFL had become a preferred study method, and 70% of participants reported continued use of MSFL. This brief, low-cost intervention resulted in enduring changes in study behavior.

Genetic variation in total number and locations of GnRH neurons identified using in situ hybridization in a wild-source population

The evolution of brain function in the regulation of physiology may depend in part upon the numbers and locations of neurons. Wild populations of rodents contain natural genetic variation in the inhibition of reproduction by winter-like short photoperiod, and it has been hypothesized that this functional variation might be due in part to heritable variation in the numbers or location of gonadotropin releasing hormone (GnRH) neurons. A naturally variable wild-source population of white-footed mice was used to develop lines artificially selected for or against mature gonads in short, winter-like photoperiods. We compared a selection line that is reproductively inhibited in short photoperiod (Responsive) to a line that is weakly inhibited by short photoperiod (Nonresponsive) for differences in counts of neurons identified using in situ hybridization for GnRH mRNA. There was no effect of photoperiod, but there were 60% more GnRH neurons in total in the Nonresponsive selection line than the Responsive selection line. The lines differed specifically in numbers of GnRH neurons in more anterior regions, whereas numbers of GnRH neurons in posterior areas were not statistically different between lines. We compare these results to those of an earlier study that used immunohistochemical labeling for GnRH neurons. The results are consistent with the hypothesis that the selection lines and natural source population contain significant genetic variation in the number and location of GnRH neurons. The variation in GnRH neurons may contribute to functional variation in fertility that occurs in short photoperiods in the laboratory and in the wild source population in winter.