Associations between diurnal preference, sleep quality and externalizing behaviours: a behavioural genetic analysis

Background - Certain aspects of sleep co-occur with externalizing behaviours in youth, yet little is known about these associations in adults. The present study: (1) examines the associations between diurnal preference (morningness versus eveningness), sleep quality and externalizing behaviours; (2) explores the extent to which genetic and environmental influences are shared between or are unique to these phenotypes; (3) examines the extent to which genetic and environmental influences account for these associations. Method - Questionnaires assessing diurnal preference, sleep quality and externalizing behaviours were completed by 1556 young adult twins and siblings. Results - A preference for eveningness and poor sleep quality were associated with greater externalizing symptoms [r=0.28 (95% CI 0.23–0.33) and 0.34 (95% CI 0.28–0.39), respectively]. A total of 18% of the genetic influences on externalizing behaviours were shared with diurnal preference and sleep quality and an additional 14% were shared with sleep quality alone. Non-shared environmental influences common to the phenotypes were small (2%). The association between diurnal preference and externalizing behaviours was mostly explained by genetic influences [additive genetic influence (A)=80% (95% CI 0.56–1.01)], as was the association between sleep quality and externalizing behaviours [A=81% (95% CI 0.62–0.99)]. Non-shared environmental (E) influences accounted for the remaining variance for both associations [E=20% (95% CI −0.01 to 0.44) and 19% (95% CI 0.01–0.38), respectively]. Conclusions - A preference for eveningness and poor sleep quality are moderately associated with externalizing behaviours in young adults. There is a moderate amount of shared genetic influences between the phenotypes and genetic influences account for a large proportion of the association between sleep and externalizing behaviours. Further research could focus on identifying specific genetic polymorphisms common to both sleep and externalizing behaviours

Interaction of laser generated ultrasonic waves with wedge-shaped samples

Wedge-shaped samples can be used as a model of acoustic interactions with samples ranging from ocean wedges, to angled defects such as rolling contact fatigue, to thickness measurements of samples with non-parallel faces. We present work on laser generated ultrasonic waves on metal samples; one can measure the dominant Rayleigh-wave mode, but longitudinal and shear waves are also generated. We present calculations, models, and measurements giving the dependence of the arrival times and amplitudes of these modes on the wedge apex angle and the separation of generation and detection points, and hence give a measure of the wedge characteristics

Aperture Integral Ultrasonic Pulse Transmission Model

This paper discusses a numerical algorithm and supporting formulation for evaluating ultrasonic pulse transmission through non-planar component geometries. The algorithm is engineered to model experimental configurations where irregularities in surface geometry preclude the use of less rigorous approaches, such as a field expansion about a single entry point. The algorithm formulation represents the transmitted pulse as a surface integral coinciding with a pulse origin aperture, employing the Green function for the water-component system. The model explicitly considers the component surface geometry over the footprint of the incident pulse, thus allowing consideration of smooth yet non-expandable (i.e. in power series about a single point) geometries, such as adjoining flat and fillet surfaces. A computationally efficient algorithm results from use of asymptotic Green function approximations. Approaches are also discussed under conditions where the asymptotic Green function expressions are singular or invalid, due to focusing by surface concavity or transmission near critical angles. Consideration of pulse time dependence represents an extension of previous work [1], as also does treatment of surface concavity and critical angle transmission. The following sections summarize theoretical formulation and algorithmic implementation, followed by the presentation of illustrative computations

Complex Wave Numbers in the Vicinity of the Schwarzschild Event Horizon

This paper is devoted to investigate the cold plasma wave properties outside the event horizon of the Schwarzschild planar analogue. The dispersion relations are obtained from the corresponding Fourier analyzed equations for non-rotating and rotating, non-magnetized and magnetized backgrounds. These dispersion relations provide complex wave numbers. The wave numbers are shown in graphs to discuss the nature and behavior of waves and the properties of plasma lying in the vicinity of the Schwarzschild event horizon.Comment: 21 pages, 9 figures, accepted for publication Int. J. Mod. Phys.

Scattering by Surface-Breaking and Sub-Surface Cracks

This paper is concerned with exact solutions and approximate solutions in the high-frequency domain for scattering of time-harmonic waves by surface-breaking cracks and cracks which are located near a free surface. Both incident surface waves and incident body waves have been considered. The high-frequency approximate solutions are generally based on elastodynamic ray theory. Some approximate solutions based on the Kirchhoff approximation have been included for comparison

Psychopathology in Dutch young adults: enduring or changeable?

This study reports on stability and change in emotional and behavioral problems in young adults over a 2-year time span. A sample of 528 18- to 22-year-olds from the general population was assessed using the Young Adult Self-Report (YASR) on two occasions. Stability coefficients for the total problem score of the YASR were 0.63 for males and 0.75 for females. Forty-nine percent of the subjects who were initially classified as deviant were still deviant at follow-up. Of all YASR syndromes, the highest stability was for the Anxious/Depressed scale

Severity and persistence of asthma and mental health: a birth cohort study

Background. The goal of the current study was to investigate asthma and mental health among youth in the community, and to consider the role of asthma severity and persistence in this link

The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents

This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these “high risk” children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative