The German Twin Family Panel (TwinLife).

The German Twin Family Panel (TwinLife) is a German longitudinal study of monozygotic and dizygotic same-sex twin pairs and their families that was designed to investigate the development of social inequalities over the life course. The study covers an observation period from approximately 2014 to 2023. The target population of the sample are reared-together twins of four different age cohorts that were born in 2009/2010 (cohort 1), in 2003/2004 (cohort 2), in 1997/1998 (cohort 3) and between 1990 and 1993 (cohort 4). In the first wave, the study included data on 4097 twin families. Families were recruited in all parts of Germany so that the sample comprises the whole range of the educational, occupational and income structure. As of 2019, two face-to-face, at-home interviews and two telephone interviews have been conducted. Data from the first home and telephone interviews are already available free of charge as a scientific use-file from the GESIS data archive. This report aims to provide an overview of the study sample and design as well as constructs that are unique in TwinLife in comparison with previous twin studies - such as an assessment of cognitive abilities or information based on the children's medical records and report cards. In addition, major findings based on the data already released are displayed, and future directions of the study are presented and discussed.

What Drives the Development of Social Inequality Over the Life Course? The German TwinLife Study.

The German twin family study 'TwinLife' was designed to enhance our understanding of the development of social inequalities over the life course. The interdisciplinary project investigates mechanisms of social inequalities across the lifespan by taking into account psychological as well as social mechanisms, and their genetic origin as well as the interaction and covariation between these factors. Main characteristics of the study are: (1) a multidimensional perspective on social inequalities, (2) the assessment of developmental trajectories in childhood, adolescence, and young adulthood in a longitudinal design by using (3) a combination of a multi-cohort cross-sequential and an extended twin family design, while (4) capturing a large variation of behavioral and environmental factors in a representative sample of about 4,000 German twin families. In the present article, we first introduce the theoretical and empirical background of the TwinLife study, and second, describe the design, content, and implementation of TwinLife. Since the data will be made available as scientific use file, we also illustrate research possibilities provided by this project to the scientific community.

Mechanisms of inappropriate defibrillator therapy in a modern cohort of remotely monitored patients.

INTRODUCTION: Defibrillator (ICD) technology and monitoring are evolving rapidly. We investigated the mechanisms of inappropriate ICD therapies in a modern cohort of patients followed at our institution via remote monitoring. METHODS: From September 2009 to March 2011, a total of 2,050 ICD patients (19,600 patient-months) were remotely followed. All events (shocks and antitachycardia pacing) were adjudicated by arrhythmia specialists. RESULTS: A total of 249 patients received ICD therapy (34% inappropriate therapy). Inappropriate ICD shocks affected 33 (1.6%) patients. There were a total of 249 inappropriate episodes in 85 patients. Supraventricular tachycardia (SVT) with 1:1 atrioventricular association was the predominant mechanism accounting for 133 episodes in 50 patients, followed by atrial fibrillation (97 episodes in 27 patients). T-wave oversensing (16 episodes in five patients), electromagnetic interference (two episodes in two patients), and ectopic beats (one episode in one patient) accounted for a small proportion of events. There were 35 arrhythmic episodes in five patients that could not be classified, all in patients with single-chamber devices. There were no differences in these results by device manufacturer. CONCLUSIONS: Despite many technological advances, inappropriate ICD shocks still occur but at very low rates and SVT with 1:1 atrioventricular association represents their most common mechanism.

The effects of parenting on early adolescents' noncognitive skills: Evidence from a sample of twins in Germany.

Many theories in the social sciences assume that parenting affects child development. Previous research mostly supports the notion that parenting affects the skill development of children in early childhood. There are fewer studies testing whether parenting in early adolescence has such an influence. We estimate the effects of parenting on early adolescents' noncognitive skills using data from the German Twin Family Panel (TwinLife). Specifically, we look at the effects of parenting styles, parental activities, and extracurricular activities on the academic self-concept, motivation, self-esteem, self-efficacy, and locus of control of 10 to 14 years old children. To control for unobserved heterogeneity and reverse causality, we employ twin fixed-effects models combined with longitudinal information. In addition, MZ twin fixed effects models also control for genetic confounding. Our findings provide no support to the notion that parenting styles, parental activities, and extracurricular activities in early adolescence affect the development of children's noncognitive skills. We conclude that our results, in combination with the majority of evidence from previous research, are in line with a model according to which parenting has larger effects on the skill development of children in early childhood than in early adolescence.

Risk assessment of R-on-T event based on modeled QT-RR relationship.

BACKGROUND: R-on-T event is a well-known trigger of ventricular tachycardia (VT) and ventricular fibrillation (VF). We propose a method to estimate the risk of R-on-T event from the inter-beat (RR) intervals based on modeled QT-RR relationship. METHODS: We retrospectively analyzed the Spontaneous Ventricular Tachyarrhythmia Database and the HAWAI Registry, which include a total of 397 RR interval recordings from 116 implantable cardioverter defibrillator patients. For each RR interval time series, QT intervals were estimated from the weighted average of preceding RR intervals using Bazett, Fridericia, and linear formulas. The risk score (RS) of each cycle was calculated to quantify the probability of R-on-T event based on the timing of R-wave relative to the estimated T-end. We identified 52,440 ectopic beats (EBs) episodes, 280 nonsustained VT (NSVT) episodes, and 352 sustained VT/VF episodes. The RS of episode onset and the prematurity index (PMI) of the initiating beat were compared. RESULTS: Using different QT-RR models, R-on-T events were respectively detected in 9% EB, 45% NSVT, 69% VT/VF (Bazett); in 6% EB, 41% NSVT, 65% VT/VF (Fridericia); and in 7% EB, 42% NSVT, 66% VT/VF (linear). No R-on-T event was found in normal beats. Consistent among three QT-RR models, the RS of episode onset rises sharply from EB to NSVT and to VT/VF episodes. In contrast, no trend in PMI is found. CONCLUSIONS: The risk of R-on-T can be estimated from RR intervals, based on modeled QT-RR relationship. An episode onset with higher RS has increased risk of developing into NSVT or VT/VF.

Analyzing rating distributions with heaps and censoring points using the generalized Craggit model.

In this article, we introduce a new, highly flexible model to analyze distributions with heaps and censoring points, which we call the generalized Craggit model. Distributions with heaps and censoring points can be found in many social science applications. For example, such distributions can be the result of sequential or multistep rating processes. Our model is a combination of a Craggit model and a generalized ordered probit model. It can account for multiple heaps and censoring points in distributions. We used this model to analyze a factorial survey experiment on earnings justice attitudes in the SOEP-Pretest 2008. In this experiment, a three-step rating instrument was used, which resulted in a rating distribution with heaps and censoring. Our generalized Craggit model fits the data of this experiment much better than a hierarchical linear model, which is the method that is usually implemented to analyze factorial survey experiments.

Open source model for generating RR intervals in atrial fibrillation and beyond.

BACKGROUND: Realistic modeling of cardiac inter-beat (RR) intervals is highly desirable for basic research in cardiac electrophysiology, clinical management of heart diseases, and developing signal processing tools for ECG analysis. METHODS: We present an open source computer model that is capable to generate realistic time series of RR intervals in both physiologic and pathologic conditions. Detailed model structure and the software implementation are described. RESULTS: Examples are provided on how to use this model to generate RR intervals in atrial fibrillation with ventricular pacing, normal sinus rhythm with heart rate variability, and typical atrial flutter with atrioventricular block. The extensibility of the model is also discussed. CONCLUSION: The present computer model provides a unified platform wherein various types of ventricular rhythm can be simulated. The availability of this open source model promises to support and stimulate future studies.

Computer modeling of ventricular rhythm during atrial fibrillation and ventricular pacing.

We propose a unified atrial fibrillation (AF)-ventricular pacing (VP) (AF-VP) model to demonstrate the effects of VP on the ventricular rhythm during atrial fibrillation AF. In this model, the AV junction (AVJ) is treated as a lumped structure characterized by refractoriness and automaticity. Bombarded by random AF impulses, the AVJ can also be invaded by the VP-induced retrograde wave. The model includes bidirectional conduction delays in the AVJ and ventricle. Both refractory period and conduction delay of the AVJ are dependent upon its recovery time. The electrotonic modulation by blocked impulses is also considered in the model. Our simulations show that, with proper parameter settings, the present model can account for most principal statistical properties of the RR intervals during AF. We further demonstrate that the AV conduction property and the ventricular rate in AF depend on both AF rate and the degree of electrotonic modulation in the AVJ. Finally, we show that multilevel interactions between AF and VP can generate various patterns of ventricular rhythm that are consistent with previous experimental observations.

High-performance field effect transistors from solution processed carbon nanotubes.

Nanoelectronic field effect transistors (FETs) are produced using solution processed individual carbon nanotubes (CNTs), synthesized by both arc discharge and laser ablation methods. We show that the performance of solution processed FETs approaches that of CVD-grown FETs if the nanotubes have minimal lattice defects and are free from surface contamination. This is achieved by treating the nanotubes to a high-temperature vacuum annealing process and using 1,2-dichloroethane for dispersion. We present CNT FETs with mobilities of up to 3546 cm(2)/(V s), transconductance of 4.22 µS, on-state conductance of 9.35 µS and on/off ratios as high as 10(6). High-resolution transmission electron microscopy is used to examine the presence of catalyst particles and amorphous carbon on the surface and Raman spectroscopy is used to examine the lattice defects, both of which lead to reduced device performance.

Ventricular rate smoothing for atrial fibrillation: a quantitative comparison study.

AIMS: To quantitatively compare the ventricular rate-smoothing (VRS) effects of different ventricular pacing (VP) protocols for atrial fibrillation (AF). METHODS AND RESULTS: Using a recently developed open-source model that can simulate the ventricular response in AF and VP, the performance of fixed-rate pacing and four previously published VRS algorithms were assessed by the mean RR (mRR), the root mean square of successive RR differences (RMSSD), the percentage of ventricular senses (VS%), and the percentage of short RR intervals (sRR%). All pacing protocols cause rate-dependent reduction of RMSSD, VS%, and sRR% with or without shortening of mRR compared to spontaneous AF. Fixed-rate pacing was more sensitive to the intrinsic rate than the VRS algorithms. The performance was generally comparable between different VRS algorithms, although higher mRR and VS% can be achieved at the expense of larger RMSSD and sRR%. CONCLUSION: The effect of VP on ventricular rhythm in AF depends on both intrinsic rate and the aggressiveness of the pacing protocol. Adequate rate control is necessary for effective operation of the VRS algorithm. Choosing VRS algorithm should balance between the beneficial effects of rate regularization and the negative effects of increasing heart rate and percentage of VP.

On the role of ventricular conduction time in rate stabilization for atrial fibrillation.

AIM: Ventricular pacing (VP) could stabilize the ventricular rhythm in atrial fibrillation (AF). This study investigates the role of ventricular conduction time (VCT) in rate stabilization for AF. METHODS AND RESULTS: A novel computer model was used to generate various patterns of RR intervals in AF. For each model configuration, the rate stabilization effect of VP was compared with respect to different VCTs. In all tested cases, the ventricular rate in AF could be stabilized at pacing intervals longer than the shortest spontaneous RR intervals. For each model configuration, slightly longer pacing interval (difference <100 ms) was needed to achieve 95% VP when the antegrade/retrograde VCT was increased from 10/10 to 110/110 ms, whereas the VCT had less effect at lower pacing rate. Although longer VCT was associated with increased percentage of ventricular fusion, its role was diminished at higher pacing rate when more retrograde waves could conduct to the atrium. CONCLUSION: Ventricular conduction time has limited effects on rate stabilization, which could be explained by multi-level interactions between antegrade waves induced by AF and retrograde waves induced by VP.

Validation of a novel atrial fibrillation model through simulated atrial pacing protocols.

We have previously reported a novel model to elucidate the effects of ventricular pacing (VP) on RR intervals during atrial fibrillation (AF). This model treats the AV junction (AVJ) as a lumped structure with defined conductivity, refractoriness and automaticity. We have shown that this model could account for various patterns of RR intervals that are consistent with experimental observations. In this study, we further validate this model by comparing its behavior with that of a real AVJ obtained in isolated rat heart preparation, through application of programmed atrial pacing protocols. We demonstrate that the AV conduction time and ventricular response of the present model are consistent with experimental findings, thus providing additional evidence to support the validity of our model.

First multi-centre evaluation of a knowledge-based implant-assistant for implantable cardioverter-defibrillators.

AIMS: Modern implantable cardioverter-defibrillators (ICDs) place increasing demands on the physician, as their complexity requires more and more knowledge and effort in handling them. To overcome this problem an implant-assistant has been developed, which transfers clinical data entered by the physician into a complete set of parameters for programming a dual-chamber ICD (Tachos-DR, Biotronik, Berlin, Germany) at DFT testing (DFT-Prog) and first permanent programming (Perm-Prog) after implant. METHODS AND RESULTS: Routine ICD implantations were initially evaluated by clinical experts at 19 centres in USA and Europe from 178 patient files. The rating of parameters was related to the number of parameters available in each patient. For DFT-Prog, 98.4% of parameter suggestions were identical to experts' expectations, an additional 1.0% were accepted, 0.5% were rejected, and none was considered harmful. This resulted in an overall acceptance of 94.4% of the DFT-Prog. For Perm-Prog, 96.1% of parameters were identical to those advised by experts, an additional 2.4% were accepted, 1.5% rejected, and seven parameters (0.04%) were considered potentially harmful by experts with an overall acceptance of 86.5%. Adaptation of the implant-assistant increased the overall acceptance to 100% for DFT-Prog and 90.6% for first Perm-Prog without any potentially harmful suggestions. CONCLUSION: The ICD implant-assistant, which allows the physician to programme ICDs directly from clinical data, is a promising method to simplify the programming of modern ICDs.

Adaptive ventricular rate smoothing during atrial fibrillation: a pilot comparison study.

An adaptive ventricular rate smoothing (VRS) algorithm is developed to regularize the ventricular rate during atrial fibrillation (AF) by means of ventricular pacing (VP). Using a quantitative AF-VP model, we conduct pilot study to compare its performance with three other VRS algorithms. Simulations show that all VRS algorithms are effective to stabilize the heart rate during AF when intrinsic ventricular rate is not higher than the maximum pacing rate. The effect of VRS is diminished as the intrinsic ventricular rate increases, whereas slower intrinsic ventricular rate renders more aggressive VP. Compared to other methods, the Adaptive-VRS algorithm tends to stabilize the ventricular rate during AF with less VP, while intrinsic ventricular responses with physiological rate and rhythm are preferably preserved.