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This three-wave study examined the relationship between life events and sense of coherence (SOC) throughout adolescence by using genetically informative random intercept cross-lagged panel models. We also examined the genetic and environmental contribution to variance in the measured constructs. The data come from a Norwegian population-based twin sample (N = 2,878). Life events and SOC were associated, and both showed substantial genetic variance. Negative longitudinal effects were observed from negative dependent life events to SOC, from SOC to negative dependent life events and from SOC to positive dependent life events. However, these longitudinal effects were negligible in magnitude. In summary, the associations between all three clusters of life events and SOC were almost completely accounted for by shared genetic influences.

The DSM-IV personality disorders (PDs) are comorbid with alcohol use disorder (AUD) and with each other. It remains unclear which PD criteria are most likely to drive onset and recurrence of AUD and which are merely confounded with those criteria. We determine which individual PD criteria predict AUD and the degree of underlying genetic and/or environmental aetiology.A prospective observational twin study.Norway 1999-2011.A total of 2528 and 2275 Norwegian adult twins in waves 1 and 2 variable-selection analyses, and 2785 in biometric analyses.DSM-IV PDs and their 80 criteria were assessed using a structured personal interview, and AUD using the World Health Organization's Composite International Diagnostic Interview.In a variable-selection analysis, two PD criteria were associated with AUD even after taking all the other criteria into account: criterion 8 of antisocial PD (childhood conduct disorder) and criterion 4 of borderline PD (self-damaging impulsive behaviours). Adjusting for each other, their respective odds ratios were 3.4 [confidence interval (CI) = 2.1-5.4] and 5.0 (CI = 3.3-7.7). Endorsement strength of the criteria was associated with AUD in a dose-response manner and they explained 5.5% of variation in AUD risk-more than the full diagnoses of antisocial and borderline PDs together (0.5%). The association between borderline criterion 4 and AUD 10 years later derived mainly from their overlapping genetic factors, whereas the association between antisocial criterion 8 and AUD 10 years later was due to both genetic and non-genetic factors.Conduct disorder and self-harming impulsivity are the foremost risk traits for alcohol use disorder among the 80 personality disorder criteria of DSM-IV, predicting alcohol use disorder more effectively than personality disorder diagnoses. The twin-study analysis suggested that conduct disorder represents a joint genetic and developmental risk for alcohol use disorder and that impulsivity is a genetic risk.

The goal of this project was to implement and evaluate an automatic face recognition system. Face localization was adapted from the algorithm of Rowley et.al. A 20*20 pixel sliding window scans a pyramid of the input image, feeding into several neural networks. The router network estimates rotation, while three detector networks classify the window as a face or non-face. This approach is very computationally intensive, and estimating rotation is the most demanding aspect. Our contribution to the localization algorithm is to reduce this processing time by i) using a genetic algorithm to evolve a more sparsely connected router network, and ii) to limit the search space by thresholding the input image on skin colour and texture. An eigenface based algorithm was used for face recognition. Our contribution was to have the system automatically extract multiple and differently segmented faces from the training image, rather than manually segmenting a single face. Evaluation of the localization algorithm demonstrated that it is generally robust, able to correctly and accurately segment faces despite variations in lighting, rotation, scale, facial expression and occlusion. Furthermore, although the difference between network topologies was small, the evolved router topology improved speed by roughly 13%, while improving the localization rate compared to Rowleys fully connected topology by 3%. Texture thresholding reduced the running time of the algorithm by almost two thirds in both colour and grayscale images, while skin colour thresholding independently reduced the running time by 45%. In colour images the combined effect was a reduction in processing time of 75%. Benchmarking of the recognition algorithm demonstrated that eigenface-based recognition is very sensitive to variations in face segmentation relative to the stored template. However, because automatic segmentation is likely to vary somewhat compared to a manual segmentation of the same face, performance of the eigenface based approach can be improved by automatically extracting and storing several slightly differently segmented templates per person. The program was implemented in C, and new libraries for neural networks, image processing, TIFF reading/writing and genetic algorithms were written to make the system fast and flexible.