Validation of Relationship between Patients' Descriptions of Pruritus and Patient-burden of Chronic Pruritus using Structural Equation Modelling.

Patients with chronic itch describe their pruritus in a wide variety of ways. However, these subjective descriptions are often not taken into consideration by physicians. This study aimed to validate patients' descriptions of pruritus, and to investigate the relationship between various descriptions of pruritus and the patient burden of chronic pruritus by examining the mediating effects of sleep disturbance and sexual dysfunction on patient's quality of life, as predicted by various descriptions of pruritus. Exploratory and confirmatory factor analyses were performed to identify the factor structure measured by 11 descriptions of pruritus. The study then analysed differences in the degree of sleep disturbance, sexual dysfunction, and quality of life deterioration factors using a structural equation modelling method. Using data from 419 patients with chronic pruritus, 11 descriptions of pruritus were classified into 2 groups: (i) sensory pruritus (i.e. stinging, stabbing, burning, painful, formication, throbbing, and cold) that are linked with descriptions of pruritus patterns; and (ii) affective pruritus (i.e. annoying, unbearable, worrisome, and warm) from patient reports of psychological or emotional distress. The study found that affective pruritus decreases patient's quality of life either directly or indirectly through sleep disturbance. In conclusion, clues about a patients' sleep disturbance or poor quality of life can be obtained through their descriptions of pruritus.

A Longitudinal Study of Assisted Infant Toilet Training During the First Year of Life.

OBJECTIVE: Previous retrospective studies have examined elimination signals, stool toileting refusal, and completion age in Assisted Infant Toilet Training (AITT). The aim of this longitudinal cohort study was to describe the practice of AITT and caregiver satisfaction in a primarily Western setting during the first year of life. METHODS: Families who started AITT before 4 months of age were recruited. Standardized interviews of caregivers were conducted at 1- to 2-month intervals. To identify trends over time, data were fitted to a linear mixed-effect model. Data were analyzed according to five 2-month blocks, starting at 3 to 4 months. RESULTS: Of 85 participating families, 87 children started AITT at a mean age of 2.5 months. At all age intervals, 88% to 94% of caregivers could identify elimination signals. Toileting attempts decreased from 10/day at 3 to 4 months to 7/day at 11 to 12 months (p < 0.001). Many families (45%-53%) practiced AITT on a part-time basis. Daytime dryness was noted in 12% to 14% of infants throughout the first year. Although more than 63% of families used cloth or disposable diapers throughout this study, use of trainers and underwear increased significantly by 2- to 3-fold (p < 0.01 for both). Caregiver satisfaction was high overall. Although negatively associated with potty refusal, it was positively associated with daytime and nighttime dryness, perceived elimination signals, and a better understanding of their infant's needs (p < 0.001 for all). CONCLUSION: This study demonstrates that AITT is a worthy viable alternative to the use of diapers even in Western settings. Better understanding of AITT provides a new perspective to properly meet infants' basic needs.

Can Policy Promote Adoption or Outcomes of Evidence-based Prevention Programming?: a Case Illustration of Positive Behavioral Interventions and Supports.

This study examined the impact of a state policy requiring that any school with a habitual truancy rate of 8% or higher to be trained in Tier 1 school-wide Positive Behavioral Interventions and Supports (SW-PBIS). A regression discontinuity (RD) design was used to examine how the schools' mandate status related to SW-PBIS training as well as student suspensions, truancy, and achievement in 410 public middle and high schools, of which 261 were affected by the mandate. We further examined the growth trajectories (i.e., improvement) of implementation fidelity over time using growth mixture modeling (GMM). Contrary to the intent of the policy to improve student outcomes, the RD results suggested that the mandate did not significantly impact reading and math achievement, truancy rates, or SW-PBIS training in 2010-2011 through 2013-2014. Mandated schools had higher suspension rates in 2010-2011 through 2013-2014 than the non-mandated schools; however, these differences in the suspension rates appear to have persisted from years prior to the mandate. Descriptive analyses suggested that mandated schools had statistically significantly higher rates of training, and the GMM analyses on the fidelity data indicated that mandated schools were significantly more likely to be in an improving implementation growth trajectory over time. Taken together, results suggested that the policy showed some promise for improving SW-PBIS training and fidelity over time, but it had little to no impact on student outcomes.

Participants' Satisfaction with the Atopic Dermatitis Education Program: Assessing the Impact of Each Content Using Structural Equation Modeling.

BACKGROUND: Only a few studies have tried to assess factors relevant to the satisfaction of the participants in atopic dermatitis (AD) educational programs. More systematic modeling of this issue is needed. OBJECTIVE: To examine the benefit of a conjoint educational program for AD on patients and caregivers in a clinical setting. METHODS: In a half-day educational program called "AD school", 831 people (493 patients and 338 family members) participated for 8 years. Various educational and entertaining programs were provided. The on-site survey was administered to measure participants' satisfaction and perception of the benefit. We applied structural equation modeling to identify the relations among satisfaction and perception. RESULTS: A total of 209 family survey data was obtained and analyzed. The survey items were grouped into four categories. The categories were classified as individual education, group education, fun activity, and overall satisfaction (fun, benefit, intention to re-join and recommend to others). According to the model that we built, comprehensive group education was demonstrated to be the most relevant factor affecting overall satisfaction. CONCLUSION: Our holistic approach would allow dermatologists to improve the efficacy of the conjoint educational program for AD.

Deconstructing bullying roles: A longitudinal latent profile analysis of bullying participant behaviors for students in grades 4 through 12.

Bullying behavior is understood as a complex social phenomenon that includes many, and sometimes overlapping, bullying participant behaviors. The current study utilized latent profile analysis (LPA) at two time points approximately one year apart and examined what bullying participant behavior groups emerged based on students' reported levels of bullying, assisting, victimization, defending, and outsider behavior. Additionally, longitudinal latent profile analyses (LLPA) were utilized to examine potential changes in groups over time. Results suggested four groups found at two timepoints: (a) Uninvolved-Occasional Defending, with defending at a monthly rate and infrequent engagement in other behaviors; (b) Frequent Defending-Occasional Victimization, with monthly victimization and weekly defending behaviors; (c) Frequent Victimization-Occasional Broad Involvement, with weekly levels of victimization and monthly bullying, defending, and outsider behaviors; and (d) Frequent Broad Involvement, with weekly engagement in all of the bully participant behaviors (i.e., bullying, assisting, victimization, defending, and outsider behavior). The largest proportion of students (more than half) were in the Uninvolved-Occasional Defending group, which was also the most stable group over time. The smallest group (7%) was Frequent Broad Involvement, which was the least stable group over time, with students in this group typically moving to groups with at least occasional broad involvement of bullying participant behaviors. More male students than female students were in both broad involvement groups (i.e., Frequent Victimization-Occasional Broad Involvement; Frequent Broad Involvement) and more female students than male students, as well as more elementary students than secondary students, were in the Frequent Defending-Occasional Victimization group. The current study suggests that researchers should use caution when categorizing or conceptualizing simple bullying participant roles such as bully or victim, or even "bully-victim," especially if the other bullying participant behaviors are not assessed. Practitioners should develop interventions that capitalize on the high proportions of students engaging in some level of defending and account for the complex social ecology that suggests that students are engaging in complex overlapping patterns of bullying participant behaviors.

A knowledge-based multivariate statistical method for examining gene-brain-behavioral/cognitive relationships: Imaging genetics generalized structured component analysis.

With advances in neuroimaging and genetics, imaging genetics is a naturally emerging field that combines genetic and neuroimaging data with behavioral or cognitive outcomes to examine genetic influence on altered brain functions associated with behavioral or cognitive variation. We propose a statistical approach, termed imaging genetics generalized structured component analysis (IG-GSCA), which allows researchers to investigate such gene-brain-behavior/cognitive associations, taking into account well-documented biological characteristics (e.g., genetic pathways, gene-environment interactions, etc.) and methodological complexities (e.g., multicollinearity) in imaging genetic studies. We begin by describing the conceptual and technical underpinnings of IG-GSCA. We then apply the approach for investigating how nine depression-related genes and their interactions with an environmental variable (experience of potentially traumatic events) influence the thickness variations of 53 brain regions, which in turn affect depression severity in a sample of Korean participants. Our analysis shows that a dopamine receptor gene and an interaction between a serotonin transporter gene and the environment variable have statistically significant effects on a few brain regions' variations that have statistically significant negative impacts on depression severity. These relationships are largely supported by previous studies. We also conduct a simulation study to safeguard whether IG-GSCA can recover parameters as expected in a similar situation.

Glycemic control in youth-onset type 2 diabetes correlates with weight loss.

OBJECTIVE: To identify risk factors for glycemic failure in youth with type 2 diabetes (T2D). METHODS: A retrospective review of HbA1c, anthropomorphic measures, medication records, and laboratory studies was performed using registry data from a dedicated pediatric T2D clinic. Latent profile analysis (LPA) was performed to model longitudinal trajectory of HbA1c over 5 years. RESULTS: The registry includes 229 youth with T2D, of whom 80% self-identify as Latinx. The odds ratio (OR) for uncontrolled diabetes 5 years after diagnosis correlated with diagnostic HbA1c, with OR of 2.41 if HbA1c at diagnosis >8.5% (sensitivity 68%, specificity 54%, P = .015). LPA modeling identified three HbA1c profiles: (a) mean HbA1c <8% throughout the 5 years, (b) persistent elevation of mean HbA1c >9%, and (c) mean HbA1c of 12% at diagnosis, rapid decline to 6.4% by 4 to 6 months, and increase to 11% by 18 months. Our analysis of medication regimen showed that, amongst patients treated with metformin, the addition of multiple daily injections (MDI) did not improve HbA1c compared to those on basal insulin. Finally, weight loss over the 1 year after diagnosis correlated with improvement in HbA1c in both subjects prescribed metformin monotherapy, as well as insulin-containing regimen. CONCLUSION: Youth with T2D exhibit distinct HbA1c profiles. Patients with diagnostic HbA1c >8.5% are at high risk for glycemic failure, irrespective of short-term improvement in HbA1c. Weight management has the potential to improve short-term HbA1c outcome in youth with T2D. Additional studies are needed to determine the role of medication adherence on glycemic control.

Human Milk Oligosaccharides and Hispanic Infant Weight Gain in the First 6 Months.

OBJECTIVE: The aim of this study was to determine whether human milk oligosaccharides (HMOs) at 1 month predicted infant weight gain at 6 months and whether associations varied by HMO secretor status. METHODS: Participants were 157 Hispanic mother-infant pairs. Human milk samples were collected at 1 month. Nineteen individual HMOs were analyzed using high-performance liquid chromatography, and secretor status was determined by the presence of 2'-fucosyllactose or lacto-N-fucopentaose (LNFP) I. Infant weight was measured at 1 and 6 months. Path analysis was used to test effects of HMO composition on infant weight gain, adjusting for maternal age, prepregnancy BMI, and infant age, sex, and birth weight. RESULTS: In the total sample, higher LNFPII predicted lower infant weight gain (g1 = -4.1, P = 0.004); this was observed in both nonsecretor (g1 = -3.0, P = 0.006) and secretor groups (g1 = -4.7, P = 0.014). In the nonsecretor group, higher lacto-N-neotetraose (g1 = 7.6, P = 0.011) and disialyllacto-N-tetraose (g1 = 14.3, P = 0.002) predicted higher infant weight gain. There were no other associations in the secretor group. CONCLUSIONS: Our data suggest that higher LNFPII in human milk may decrease obesity risk across all infants, whereas higher lacto-N-neotetraose and disialyllacto-N-tetraose may increase obesity risk in infants of nonsecretors only.

Associations of Maternal Prenatal Drug Abuse With Measures of Newborn Brain Structure, Tissue Organization, and Metabolite Concentrations.

Importance: Increasing rates of illicit drug use during pregnancy may be associated with risk for long-term health problems in prenatally exposed children. Objective: To identify the associations of prenatal exposure to illicit drugs with organization of the newborn brain. Design, Setting, and Participants: For this cohort study, a volunteer sample of 210 illicit drug-using and nonusing mothers and their newborns was enrolled from prenatal clinics and drug abuse treatment programs in New York, New York. Enrollment, scanning, and long-term follow-up occurred from September 2004 through February 2012, and image processing and statistical analyses continued through fall 2018. In addition to 26 participants with incomplete data, a total of 64 mothers were lost to follow-up during pregnancy, and 13 newborns were lost to follow-up at birth because of perinatal complications. Exposures: Newborns were assigned to 1 of 4 primary exposure groups based on the history of most frequent maternal drug use: marijuana, cocaine, methadone maintenance, and/or heroin. Unexposed newborns were controls. Main Outcomes and Measures: Unsedated magnetic resonance imaging (MRI) of newborn brains was performed shortly after birth. Infant neurodevelopmental outcomes were assessed at age 12 months. MRI modalities included anatomical imaging, diffusion tensor imaging, T2 relaxometry, and magnetic resonance spectroscopic imaging. Infant neurodevelopmental outcomes included Bayley scales of infant development-III and Vineland Adaptive Behavior Scales. Statistical analyses were performed with results represented on the brain images. Results: Of 118 mothers, 42 (35%) were in the control group (mean [SD] age, 25.9 [6.1] years), 29 (25%) were in the cocaine group (mean [SD] age, 29.0 [6.1] years), 29 (25%) were in the marijuana group (mean [SD] age, 24.3 [5.5] years), and 18 (15%) were in the methadone and/or heroin group (mean [SD] age, 30.9 [5.7] years). Not all newborns could be scanned successfully; therefore, usable MRIs were acquired for 118 newborns from predominantly minority groups and with economically disadvantaged mothers. Anatomic abnormalities were detected in similar locations across all 3 drug exposures and included smaller volumes in the dorsal, medial, and ventral surfaces of the frontal lobe and dose-related increases in volumes in the lateral temporal lobe, dorsal parietal lobe, and superior frontal gyrus. Dose-related increases in diffusion tensor measures of tissue organization, decreases in T2 relaxometry times, and increases in spectroscopy metabolite concentrations were similar across exposures. These associations of exposures with brain measures were similar to the associations of newborn age with brain measures. The anatomic and diffusion tensor imaging measures suppressively mediated the associations of prenatal exposure with poorer 12-month infant outcomes. Conclusions and Relevance: The findings suggest that prenatal drug exposure is associated with measures of newborn brain tissue in patterns that may indicate that exposures accelerated normal fetal brain maturation, which in turn mediated the associations with poorer 12-month infant outcomes.

Human milk oligosaccharide 2'-fucosyllactose links feedings at 1 month to cognitive development at 24 months in infants of normal and overweight mothers.

BACKGROUND: Infant cognitive development is influenced by maternal factors that range from obesity to early feeding and breast milk composition. Animal studies suggest a role for human milk oligosaccharide (HMO), 2'-fucosyllactose (2'FL), on learning and memory, yet no human studies have examined its impact on infant cognitive development relative to other HMOs and maternal factors. OBJECTIVE: To determine the impact of 2'FL from breast milk feeding on infant cognitive development at 24 months of age relative to maternal obesity and breast milk feeding frequency. METHODS AND MATERIALS: Hispanic mother-infant pairs (N = 50) were recruited across the spectrum of pre-pregnancy BMI. Breast milk was collected at 1 and 6 months, and feedings/day were reported. Nineteen HMOs were analyzed using high-performance liquid chromatography, with initial interest in 2'FL. Infant cognitive development score was assessed with the Bayley-III Scale at 24 months. Linear regressions were used for prediction, and bootstrapping to determine mediation by 2'FL. RESULTS: Maternal pre-pregnancy BMI was not related to feedings/day or HMOs, but predicted poorer infant cognitive development (ß = -0.31, P = 0.03). Feedings/day (ß = 0.34) and 2'FL (ß = 0.59) at 1 month predicted better infant cognitive development (both P≤ 0.01). The association of feedings/day with infant cognitive development was no longer significant after further adjustment for 2'FL (estimated mediation effect = 0.13, P = 0.04). There were no associations of feedings/day and 2'FL at 6 months with infant cognitive development. CONCLUSIONS: Our findings suggest that maternal factors influence infant cognitive development through multiple means. Though maternal obesity may be a separate negative influence, greater frequency of breast milk feeding at 1 month contributed to infant cognitive development through greater exposure to 2'FL relative to other HMOs. The influence of 2'FL was not significant at 6 months, indicating that early exposure to 2'FL may be a critical temporal window for positively influencing infant cognitive development.

Effective interventions for depressive symptoms among caregivers of people with dementia: A systematic review and meta-analysis.

BACKGROUND: Caring for a family member with dementia puts caregivers at risk for depressive symptoms. Yet, interventions with promising effects on caregiver depressive symptoms are not well documented. AIMS: This review aimed to examine the quality and effectiveness of interventions to reduce depressive symptoms reported by caregivers of people with dementia. DESIGN: A systematic review and meta-analysis of nonpharmacological intervention trials was conducted. METHODS: The electronic databases searched included MEDLINE, CINAHL, and PsycINFO to find randomized controlled trials published between 2007 and 2017. A total of 31 randomized controlled trials were included in the meta-analysis. RESULTS: Cognitive-behavioral therapy (838 participants) showed a large, significant effect (standardized mean difference = -0.905; 95% CI = (-1.622, -0.187); p = 0.013) and mindfulness interventions (186 participants) showed moderate, significant effects (standardized mean difference = -0.578; 95% CI = (-0.881, -0.275); p < 0.001) on decreasing caregiver depressive symptoms, while psychoeducational interventions demonstrated small but significant effects (standardized mean difference = -0.244; 95% CI = (-0.395, -0.092); p = 0.002). Emotional support, cognitive rehabilitation, and multicomponent interventions showed less than small or nonsignificant effects related to depressive symptoms among caregivers. CONCLUSION: Cognitive-behavioral therapy interventions, which focus on diminishing negative thoughts and increasing positive activities, can effectively decrease depressive symptoms for caregivers of individuals with dementia. Future research is recommended to assess the long-term effectiveness of cognitive-behavioral therapy in this population.

A systematic review and meta-analysis on effective interventions for health-related quality of life among caregivers of people with dementia.

AIMS: (a) To evaluate the effectiveness of different types of psychosocial interventions on the health-related quality of life among caregivers of individuals with dementia and (b) To present an overview and assessment of the quality of the most recent intervention studies. DESIGN: A systematic review and meta-analysis. DATA SOURCES: MEDLINE, CINAHL, PsycINFO and Cochrane Library electronic databases were searched to find randomized controlled trials (RCTs) published from 2005 - 2017. Using a Boolean search, the key words 'caregivers', 'dementia' and 'quality of life' were combined. The search was completed in January 2018. REVIEW METHODS: A total of 26 RCTs were included. Intervention details such as content, mode of delivery and duration were reviewed, and each study's risk of bias was assessed. The effectiveness of each type of intervention was calculated using the Hedges G and a random-effects model. RESULTS: Multicomponent interventions, cognitive behavioural therapy and complementary alternative medicine therapy showed significant effects on improving caregiver's health-related quality of life. Psychoeducation, social support, case management and cognitive rehabilitation therapy failed to produce significant effects. CONCLUSION: Via this evidence-based systematic review, multicomponent interventions addressing a variety of caregiver needs can be an effective method for enhancing caregiver health-related quality of life. Further large number of studies are needed to verify this study results. IMPACT: The findings of this study inform clinicians which interventions are effective in improving caregivers' health-related quality of life. Defining a standardized protocol for multicomponent interventions will be helpful for clinicians to apply the intervention.

The Impact of Performing Medical/Nursing Tasks at Home Among Caregivers of Individuals With Cognitive Impairment.

Caregiving for older adults with cognitive impairment can be more difficult as caregivers are required to perform medical/nursing tasks at home. Little is known about medical/nursing tasks and their relationship to caregivers' characteristics and their effects on caregiver burden. Secondary data analyses were conducted with 423 caregivers of individuals with cognitive impairment from the 2015 National Alliance for Caregiving (NAC) and American Association of Retired Persons (AARP) data. In terms of the caregiving context, caregivers who performed medical/nursing tasks lived with the care recipients and provided longer hours of care than caregivers who did not perform medical/nursing tasks. When caregivers delivered medical/nursing tasks, they were 2 times more likely to experience higher levels of caregiver burden. Medical/nursing tasks can exacerbate caregiver burden. Health care providers' explanations of the needs and the benefits of performing medical/nursing tasks, as well as education and training for the tasks, are needed to reduce caregiver burden.

Exploring the challenges of medical/nursing tasks in home care experienced by caregivers of older adults with dementia: An integrative review.

AIMS: To examine prevalence, types, challenges and the impact of medical/nursing tasks (MNT) on caregivers of older adults with dementia. BACKGROUND: Medical/nursing tasks have been perceived as a professional healthcare role; however, research shows that many caregivers of older adults with dementia perform those tasks in the home, such as giving injections, tube feedings or operation of medical equipment. Little is known about the caregivers' challenges in engaging in these MNT. DESIGN: Integrative review. METHODS: Ovid MEDLINE, CINAHL, PsycINFO and Web of Science databases were searched to explore MNT among caregivers of older adults with dementia who lived in a community setting. Four quantitative and nine qualitative studies published between 1980-2018 were included. Overall, process of the review was guided by PRISMA. RESULTS: About 67% of U.S. caregivers of older adults with dementia performed MNT, including managing multiple medications, wound care and nutritional management. Care recipients' cognitive impairment complicated the provision of those tasks due to their limited cognitive functioning, behavioural changes, comorbidities and complex medication regimen. Insufficient information and training from healthcare professionals as well as caregivers' age and their own health problems made performance of those tasks even more challenging. As a result, caregivers frequently suffered from emotional distress such as worrying, anxiety and sleep disturbance. CONCLUSIONS: Medical/nursing tasks have become one of the daily tasks of caregivers of older adults with dementia within the home. However, the tasks are difficult and complicated, and inadequate support from healthcare professionals may compromise the caregivers' well-being. RELEVANCE TO CLINICAL PRACTICE: Healthcare professionals should provide education and should be aware of caregivers' needs related to MNT. Structured-medical information, skill-based instructions and hands-on training may be beneficial to decrease the caregivers' distress from MNT.

Maternal blood pressure mediates the association between maternal obesity and infant weight gain in early postpartum.

BACKGROUND: It is unknown to what extent higher maternal blood pressure (BP) in early postpartum impacts the relationship between higher maternal weight status and greater infant weight gain in early postpartum. OBJECTIVE: To evaluate the mediating role of higher maternal BP at 1 month postpartum on the association between higher maternal weight status at 1 month postpartum and greater infant weight gain over 6 months postpartum. METHODS: Participants were 169 Hispanic mother-infant pairs. Maternal body mass index (BMI) and BP were assessed at 1 month postpartum. Infant weight was measured at 1 and 6 months postpartum to calculate weight-for-age z scores (WAZ). Multiple linear regression models were used for prediction, and Sobel test was used to determine mediation. RESULTS: Controlling for maternal pre-pregnancy BMI, age, delivery mode, infant sex, and infant birth weight revealed that both maternal BMI (ß = .29) and BP (ß = .32) predicted infant WAZ gain (both P ≤ .03). However, the relationship between infant WAZ gain and maternal BMI was no longer significant after further adjustment for maternal BP, which remained significant (P < .05). Maternal BP explained 23.6% (Sobel T = 2.01) of the association between maternal BMI at 1 month and infant WAZ gain over 6 months. CONCLUSION: Our data suggest that higher maternal weight status at 1 month postpartum is related to greater infant weight gain over 6 months postpartum, and this relationship is mediated by higher maternal BP at 1 month postpartum.

A state-wide quasi-experimental effectiveness study of the scale-up of school-wide Positive Behavioral Interventions and Supports.

The three-tiered Positive Behavioral Interventions and Supports (PBIS) framework promotes the development of systems and data analysis to guide the selection and implementation of evidence-based practices across multiple tiers. The current study examined the effects of universal (tier 1) or school-wide PBIS (SW-PBIS) in one state's scale-up of this tier of the framework. Annual propensity score weights were generated to examine the longitudinal effects of SW-PBIS from 2006-07 through 2011-12. School-level archival and administrative data outcomes were examined using panel models with an autoregressive structure. The sample included 1316 elementary, middle, and high schools. Elementary schools trained in SW-PBIS demonstrated statistically significantly lower suspensions during the fourth and fifth study years (i.e., small effect size) and higher reading and math proficiency rates during the first two study years as well as in one and two later years (i.e., small to large effect sizes), respectively. Secondary schools implementing SW-PBIS had statistically significantly lower suspensions and truancy rates during the second study year and higher reading and math proficiency rates during the second and third study years. These findings demonstrate medium effect sizes for all outcomes except suspensions. Given the widespread use of SW-PBIS across nearly 26,000 schools in the U.S., this study has important implications for educational practices and policies.

Longitudinal Model Building Using Latent Transition Analysis: An Example Using School Bullying Data.

Applications of latent transition analysis (LTA) have emerged since the early 1990s, with numerous scientific findings being published in many areas, including social and behavioral sciences, education, and public health. Although LTA is effective as a statistical analytic tool for a person-centered model using longitudinal data, model building in LTA has often been subjective and confusing for applied researchers. To fill this gap in the literature, we review the components of LTA, recommend a framework of fitting LTA, and summarize what acceptable model evaluation tools should be used in practice. The proposed framework of fitting LTA consists of six steps depicted in Figure 1 from step 0 (exploring data) to step 5 (fitting distal variables). We also illustrate the framework of fitting LTA with data on concerns about school bullying from a sample of 1,180 students ranging from 5th to 9th grade (mean age = 12.2 years, SD = 1.29 years at Time 1) over three semesters. We identified four groups of students with distinct patterns of bullying concerns, and found that their concerns about bullying decreased and narrowed to specific concerns about rumors, gossip, and social exclusion over time. The data and command (syntax) files needed for reproducing the results using SAS PROC LCA and PROC LTA (Version 1.3.2) (2015) and Mplus 7.4 (Muthén and Muthén, 1998-2015) are provided as online supplementary materials.

Fitting the Fractional Polynomial Model to Non-Gaussian Longitudinal Data.

As in cross sectional studies, longitudinal studies involve non-Gaussian data such as binomial, Poisson, gamma, and inverse-Gaussian distributions, and multivariate exponential families. A number of statistical tools have thus been developed to deal with non-Gaussian longitudinal data, including analytic techniques to estimate parameters in both fixed and random effects models. However, as yet growth modeling with non-Gaussian data is somewhat limited when considering the transformed expectation of the response via a linear predictor as a functional form of explanatory variables. In this study, we introduce a fractional polynomial model (FPM) that can be applied to model non-linear growth with non-Gaussian longitudinal data and demonstrate its use by fitting two empirical binary and count data models. The results clearly show the efficiency and flexibility of the FPM for such applications.

Model Evaluation in Generalized Structured Component Analysis Using Confirmatory Tetrad Analysis.

Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling (SEM). GSCA regards weighted composites or components of indicators as proxies for latent variables and estimates model parameter via least squares without resorting to a distributional assumption such as multivariate normality of indicators. As with other SEM approaches, model evaluation is a crucial procedure in GSCA that is used to examine whether a hypothesized model is consistent with the data in hand. However, the few descriptive measures of model evaluation available for GSCA are limited to evaluating models in a more confirmatory manner. This study integrates confirmatory tetrad analysis (CTA) into GSCA for model evaluation or comparison. Although CTA has been used in factor-based SEM as an inferential statistic, CTA is actually more compatible with GSCA because it is completely free of the multivariate normality assumption. Utilizing empirical data collected for 18,174 students' social skills in an early childhood longitudinal study of 2010-11 kindergarten cohort, we demonstrate the capability and applicability of CTA in GSCA and compare its performance with existing measures for GSCA.

Breakdown of the Chiral Anomaly in Weyl Semimetals in a Strong Magnetic Field.

The low-energy quasiparticles of Weyl semimetals are a condensed-matter realization of the Weyl fermions introduced in relativistic field theory. Chiral anomaly, the nonconservation of the chiral charge under parallel electric and magnetic fields, is arguably the most important phenomenon of Weyl semimetals and has been explained as an imbalance between the occupancies of the gapless, zeroth Landau levels with opposite chiralities. This widely accepted picture has served as the basis for subsequent studies. Here we report the breakdown of the chiral anomaly in Weyl semimetals in a strong magnetic field based on ab initio calculations. A sizable energy gap that depends sensitively on the direction of the magnetic field may open up due to the mixing of the zeroth Landau levels associated with the opposite-chirality Weyl points that are away from each other in the Brillouin zone. Our study provides a theoretical framework for understanding a wide range of phenomena closely related to the chiral anomaly in topological semimetals, such as magnetotransport, thermoelectric responses, and plasmons, to name a few.