Hybridizing two-step growth mixture model and exploratory factor analysis to examine heterogeneity in nonlinear trajectories

Empirical researchers are usually interested in investigating the impacts of baseline covariates have when uncovering sample heterogeneity and separating samples into more homogeneous groups. However, a considerable number of studies in the structural equation modeling (SEM) framework usually start with vague hypotheses in terms of heterogeneity and possible reasons. It suggests that (1) the determination and specification of a proper model with covariates is not straightforward, and (2) the exploration process may be computational intensive given that a model in the SEM framework is usually complicated and the pool of candidate covariates is usually huge in the psychological and educational domain where the SEM framework is widely employed. Following \citet{Bakk2017two}, this article presents a two-step growth mixture model (GMM) that examines the relationship between latent classes of nonlinear trajectories and baseline characteristics. Our simulation studies demonstrate that the proposed model is capable of clustering the nonlinear change patterns, and estimating the parameters of interest unbiasedly, precisely, as well as exhibiting appropriate confidence interval coverage. Considering the pool of candidate covariates is usually huge and highly correlated, this study also proposes implementing exploratory factor analysis (EFA) to reduce the dimension of covariate space. We illustrate how to use the hybrid method, the two-step GMM and EFA, to efficiently explore the heterogeneity of nonlinear trajectories of longitudinal mathematics achievement data.Comment: Draft version 1.6, 08/08/2020. This paper has not been peer reviewed. Please do not copy or cite without author's permissio

Identifying Attrition Phases in Survey Data: Applicability and Assessment Study

Background: Although Web-based questionnaires are an efficient, increasingly popular mode of data collection, their utility is often challenged by high participant dropout. Researchers can gain insight into potential causes of high participant dropout by analyzing the dropout patterns. Objective: This study proposed the application of and assessed the use of user-specified and existing hypothesis testing methods in a novel setting—survey dropout data—to identify phases of higher or lower survey dropout. Methods: First, we proposed the application of user-specified thresholds to identify abrupt differences in the dropout rate. Second, we proposed the application of 2 existing hypothesis testing methods to detect significant differences in participant dropout. We assessed these methods through a simulation study and through application to a case study, featuring a questionnaire addressing decision-making surrounding cancer screening. Results: The user-specified method set to a low threshold performed best at accurately detecting phases of high attrition in both the simulation study and test case application, although all proposed methods were too sensitive. Conclusions: The user-specified method set to a low threshold correctly identified the attrition phases. Hypothesis testing methods, although sensitive at times, were unable to accurately identify the attrition phases. These results strengthen the case for further development of and research surrounding the science of attrition

A state-level study of opioid use disorder treatment access and neonatal abstinence syndrome

Background Adult opioid use and neonatal abstinence syndrome (NAS) are growing public health problems in the United States (U.S.). Our objective was to determine how opioid use disorder treatment access impacts the relationship between adult opioid use and NAS. Methods We conducted a cross-sectional state-level ecologic study using 36 states with available Healthcare Cost and Utilization Project State Inpatient Databases in 2014. Opioid use disorder treatment access was determined by the: 1) proportion of people needing but not receiving substance use treatment, 2) density of buprenorphine-waivered physicians, and 3) proportion of individuals in outpatient treatment programs (OTPs). The incidence of NAS was defined as ICD-9 code 779.5 (drug withdrawal syndrome in newborn) from any discharge diagnosis field per 1000 live births in that state. Results Unmet need for substance use disorder treatment correlated with NAS (r = 0.54, 95% CI: 0.26–0.73). The correlation between adult illicit drug use/dependence and NAS was higher in states with a lower density of buprenorphine-waivered physicians and individuals in OTPs. Conclusions Measures of opioid use disorder treatment access dampened the correlation between illicit drug use/dependence and NAS. Future studies using community- or individual-level data may be better poised to answer the question of whether or not opioid use disorder treatment access improves NAS relative to adult opioid use

Methods for Evaluating Respondent Attrition in Web-Based Surveys

Background: Electronic surveys are convenient, cost effective, and increasingly popular tools for collecting information. While the online platform allows researchers to recruit and enroll more participants, there is an increased risk of participant dropout in Web-based research. Often, these dropout trends are simply reported, adjusted for, or ignored altogether. Objective: To propose a conceptual framework that analyzes respondent attrition and demonstrates the utility of these methods with existing survey data. Methods: First, we suggest visualization of attrition trends using bar charts and survival curves. Next, we propose a generalized linear mixed model (GLMM) to detect or confirm significant attrition points. Finally, we suggest applications of existing statistical methods to investigate the effect of internal survey characteristics and patient characteristics on dropout. In order to apply this framework, we conducted a case study; a seventeen-item Informed Decision-Making (IDM) module addressing how and why patients make decisions about cancer screening. Results: Using the framework, we were able to find significant attrition points at Questions 4, 6, 7, and 9, and were also able to identify participant responses and characteristics associated with dropout at these points and overall. Conclusions: When these methods were applied to survey data, significant attrition trends were revealed, both visually and empirically, that can inspire researchers to investigate the factors associated with survey dropout, address whether survey completion is associated with health outcomes, and compare attrition patterns between groups. The framework can be used to extract information beyond simple responses, can be useful during survey development, and can help determine the external validity of survey results

Variation in Foliage Yield and Yield Component Traits and Preference for Leaf Quality Traits in Amaranthus Cruentus [L.] Genotypes

Amaranthus cruentus is a traditional leaf vegetable in Nigeria. At present, there are few commercial varieties. Development of new varieties requires systematic assessment of foliage yield and yield contributing traits. The objectives of this study are to evaluate variation for foliage yield and yield traits, determine the influence of time of harvest (4 or 5 weeks after sowing) on foliage yield, and assess preference for genotypes, leaf yield and leaf quality traits. Nine Amaranthus cruentus genotypes were grown in a randomized complete blocks design with three replications. Sunken beds were made at 1 m x 2 m, each bed was separated by alley of 1m. A total of 16 beds constituted a replicate, 8 beds were allotted to harvest at 4 weeks, another 8 beds to harvest at 5 weeks. Each bed was treated with 4 Kg of matured farmyard manure. Combined analysis of variance was performed on mean data. Participatory selection was conducted to identify preferred genotypes and horticultural traits. Genotypes were similar or dissimilar for foliage yield and yield component traits at 4 and 5 weeks harvest. Genotype by Year Interaction revealed statistically significant mean squares at 4 and 5 weeks harvest for some traits. Considering multiple traits at 4 weeks harvest, AM 25 and AM 45 performed best for leaves/plant and leaf dry weight, while AM 42 is promising for leaf yield, leaf length and leaf width. At 5 weeks harvest, AM 45 performed best for leaf yield, leaf fresh weight and dry weight. AM 25, AM 42, AM 45 and AMLOC are capable of developing rapidly and producing large quantities of biomass under short cycle harvest

Order Ten Implicit One-Step Hybrid Block Method for The Solution of Stiff Second-order Ordinary Differential Equations

A one-step hybrid block method for initial value problems of general second order Ordinary Differential Equations has been studied in this paper. The method is developed using interpolation and collocation techniques. The use of the power series approximate solution as an interpolation polynomial and its second derivative as a collocation equation is considered in deriving the method. Numerical analysis shows that the developed new method is consistent, convergent,nbspnbsp and order ten. The new method is then applied to solve the system of second-order ordinary differential equations and the accuracy is better when compared with the existing methods in terms of error

Potentials of Sludge from Drinking Water Treatment Plant for Use as Source of Soil Nutrients for Reclamation of Degraded Land

The residuals from Gubi drinking water treatment plant are usually discharged directly into the nearby streams without any form of treatment. The decomposition of the organic materials contained in the untreated sludge has caused the production of malodorous gases and unsightly condition in the area. The disposal of this sludge in an environmentally friendly manner is therefore not only desirable but necessary. The aim of this investigation was to assess the feasibility of utilizing the residuals from Gubi water treatment plant as a source of nutrients for reclamation of degraded lands especially those arising from mining activities. The study was carried out at Gubi water treatment plant located in the vicinity of Gubi Dam water reservoir.Ten sludge samples were collected from each of the three clerifiers. Important sludge properties that are known to aid nutrients status of soil were analyzed using standard laboratory procedures. The means of various soil quality parameters recorded in the WTRs were 6.8, 20.06g/kg, 34.90g/kg, 1.65g/kg, 2.30g/kg, 13.45mg/kg, 2.50Cmol/kg, 2.10Cmol/kg and 28Cmol/kg for pH, Organic C, Organic Matter, K, Total N, Olsen P, Ca, Mg and CEC respectively. The means of all the parameters analysed falls within the ranges considered good for vegetation growth. The heavy metals concentrations recorded in the residual were 1.8mg/kg, 0.1mg/kg, 2mg/kg, 29mg/kg, 66mg/kg, 15mg/kg, 8.7mg/kg, 6.2mg/kg and 0.03mg/kg for As, Cd, Pb, Cu, Zn, Ni, Co, Cr and Hg respectively. The concentrations of all the metals did not exceed the acceptable threshold limits recommended by regulatory authorities. Considering the enormous amount of plant nutrients and absence of excessive toxic metals in Gubi WTRs, it is safe to conclude that the residual can be use as a source of soil nutrients for reclamation of degraded land. Key words: Sludge, Soil Nutrients, Degraded Land, Reclamatio

Associations between Childhood Body Size, Composition, Blood Pressure and Adult Cardiac Structure: The Fels Longitudinal Study

Objectives To determine whether childhood body size, composition and blood pressure are associated with adult cardiac structure by estimating childhood “age of divergence.” Methods 385 female and 312 male participants in the Fels Longitudinal Study had echocardiographic measurements of left ventricular mass, relative wall thickness, and interventricular septal thickness. Also available were anthropometric measurements of body mass index, waist circumference, percentage body fat, fat free mass, total body fat, and systolic and diastolic blood pressures, taken in both childhood and adulthood. The age of divergence is estimated as the lowest age at which childhood measurements are significantly different between patients with low and high measurements of adult cardiac structure. Results Childhood body mass index is significantly associated with adult left ventricular mass (indexed by height) in men and women (ages of divergence: 7.5 years and 11.5 years, respectively), and with adult interventricular septal thickness in boys (age of divergence: 9 years). Childhood waist circumference indexed by height is associated with left ventricular mass (indexed by height) in boys (age of divergence: 8 years). Cardiac structure was in general not associated with childhood body composition and blood pressure. Conclusions Though results are affected by adult body size, composition and blood pressure, some aspects of adult cardiac structure may have their genesis in childhood body size

Harnessing Information Technology to Inform Patients Facing Routine Decisions: Cancer Screening as a Test Case

PURPOSE Technology could transform routine decision making by anticipating patients’ information needs, assessing where patients are with decisions and preferences, personalizing educational experiences, facilitating patient-clinician information exchange, and supporting follow-up. This study evaluated whether patients and clinicians will use such a decision module and its impact on care, using 3 cancer screening decisions as test cases. METHODS Twelve practices with 55,453 patients using a patient portal participated in this prospective observational cohort study. Participation was open to patients who might face a cancer screening decision: women aged 40 to 49 who had not had a mammogram in 2 years, men aged 55 to 69 who had not had a prostate-specific antigen test in 2 years, and adults aged 50 to 74 overdue for colorectal cancer screening. Data sources included module responses, electronic health record data, and a postencounter survey. RESULTS In 1 year, one-fifth of the portal users (11,458 patients) faced a potential cancer screening decision. Among these patients, 20.6% started and 7.9% completed the decision module. Fully 47.2% of module completers shared responses with their clinician. After their next office visit, 57.8% of those surveyed thought their clinician had seen their responses, and many reported the module made their appointment more productive (40.7%), helped engage them in the decision (47.7%), broadened their knowledge (48.1%), and improved communication (37.5%). CONCLUSIONS Many patients face decisions that can be anticipated and proactively facilitated through technology. Although use of technology has the potential to make visits more efficient and effective, cultural, workflow, and technical changes are needed before it could be widely disseminated

99MtC(I)-tricarbonyl labeling of ethylene Duamine-N,N'-DI-3-Propanoate diethyl ester as potential radiopharmaceutical agent

There is an increasing interest for the 99mTc labeling of biomolecules by using bifunctional chelating agents like ethylenediamine-N,N´-di-3-propanoate diethyl ester (deeddp). To find new ligand, which can be linked to the small biomolecules and coordinated with [99mTc(CO)3(H2O)3] + precursor, is a challenging task. Radiolabeling of deeddp with [99mTc(CO)3(H2O)3] + precursor, stability studies and biodistribution of formed complexes were carried out, including challenge with histidine. Radiochemical yield of 99mTc(I)-tricarbonyl-deeddp complexes was higher than 95%. These complexes were stable in vitro and showed a very good biological behavior. The radiochemical and biological features of the novel 99mTc(I)-complexes, as well as, the nature of the ligands, make them very promising candidates for labeling of tumor specific biomolecules.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201