Fiber-Reinforced Wood Composites

The technical feasibility of producing internally reinforced laminated wood is evaluated experimentally. Numerous fiber reinforcements and adhesives are assessed, and effects of several processing and environmental parameters are included. Results demonstrate the increased strength and stiffness to be achieved under both tension and flexure by adding fiber reinforcement. Glass reinforcement is particularly suitable

Declines in prevalence of adolescent substance use disorders and delinquent behaviors in the USA: A unitary trend?

AbstractBackgroundDownward trends in a number of adolescent risk behaviors including violence, crime, and drug use have been observed in the USA in recent years. It is unknown whether these are separate trends or whether they might relate to a general reduction in propensity to engage in such behaviors. Our objectives were to quantify trends in substance use disorders (SUDs) and delinquent behaviors over the 2003–2014 period and to determine whether they might reflect a single trend in an Externalizing-like trait.MethodsWe analyzed data from 12 to 17 year old participants from the National Survey on Drug Use and Health, a representative survey of the household dwelling population of the USA, across the 2003–2014 period (N = 210 599). Outcomes included past-year prevalence of six categories of substance use disorder and six categories of delinquent behavior.ResultsTrend analysis suggested a net decline of 49% in mean number of SUDs and a 34% decline in delinquent behaviors over the 12-year period. Item Response Theory models were consistent with the interpretation that declines in each set of outcomes could be attributed to changes in mean levels of a latent, Externalizing-like trait.ConclusionsOur findings suggest that declines in SUDs and some delinquent behaviors reflect a single trend related to an Externalizing-like trait. Identifying the factors contributing to this trend may facilitate continued improvement across a spectrum of adolescent risk behaviors.</jats:sec

Emotional disorders: Cluster 4 of the proposed meta-structure for DSM-V and ICD-11

Background The extant major psychiatric classifications DSM-IV, and ICD-10, are atheoretical and largely descriptive. Although this achieves good reliability, the validity of a medical diagnosis would be greatly enhanced by an understanding of risk factors and clinical manifestations. In an effort to group mental disorders on the basis of aetiology, five clusters have been proposed. This paper considers the validity of the fourth cluster, emotional disorders, within that proposal.Method We reviewed the literature in relation to 11 validating criteria proposed by a Study Group of the DSM-V Task Force, as applied to the cluster of emotional disorders.Results An emotional cluster of disorders identified using the 11 validators is feasible. Negative affectivity is the defining feature of the emotional cluster. Although there are differences between disorders in the remaining validating criteria, there are similarities that support the feasibility of an emotional cluster. Strong intra-cluster co-morbidity may reflect the action of common risk factors and also shared higher-order symptom dimensions in these emotional disorders.Conclusion Emotional disorders meet many of the salient criteria proposed by the Study Group of the DSM-V Task Force to suggest a classification cluster.</p

The Genetic and Environmental Sources of Resemblance Between Normative Personality and Personality Disorder Traits

Recent work has suggested a high level of congruence between normative personality, most typically represented by the big five factors, and abnormal personality traits. In 2,293 Norwegian adult twins ascertained from a population-based registry, the authors evaluated the degree of sharing of genetic and environmental influences on normative personality, assessed by the Big Five Inventory (BFI), and personality disorder traits (PDTs), assessed by the Personality Inventory for DSM-S-Norwegian Brief Form (PID-5NBF). For four of the five BFI dimensions, the strongest genetic correlation was observed with the expected PID-5-NBF dimension (e.g., neuroticism with negative affectivity [+], conscientiousness with disinhibition [-]). However, neuroticism, conscientiousness, and agreeableness had substantial genetic correlations with other PID-S-NBF dimensions (e.g., neuroticism with compulsivity [+], agreeableness with detachment [-]). Openness had no substantial genetic correlations with any PID-5-NBF dimension. The proportion of genetic risk factors shared in aggregate between the BFI traits and the PID-5-NBF dimensions was quite high for conscientiousness and neuroticism, relatively robust for extraversion and agreeableness, but quite low for openness. Of the six PID-S-NBF dimensions, three (negative affectivity, detachment, and disinhibition) shared, in aggregate, most of their genetic risk factors with normative personality traits. Genetic factors underlying psychoticism, antagonism, and compulsivity were shared to a lesser extent, suggesting that they are influenced by etiological factors not well indexed by the BFI

Bilateral Asymmetry in the Single Leg Step Down among Young Healthy Adults

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Estimating flexibility preferences to resolve temporal scheduling conflicts in activity-based modelling

This paper presents a novel activity-based demand model that combines an optimisation framework for continuous temporal scheduling decisions (i.e. activity timings and durations) with traditional discrete choice models for non-temporal choice dimensions (i.e. activity participation, number and type of tours, and destinations). The central idea of our approach is that individuals resolve temporal scheduling conflicts that arise from overlapping activities, e.g. needing to work and desiring to shop at the same time, in order to maximise their daily utility. Flexibility parameters capture behavioural preferences that penalise deviations from desired timings. This framework has three advantages over existing activity-based modelling approaches: (i) the time conflicts between different temporal scheduling decisions including the activity sequence are treated jointly; (ii) flexibility parameters follow a utility maximisation approach; and (iii) the framework can be used to estimate and simulate a city-scale case study in reasonable time. We introduce an estimation routine that allows flexibility parameters to be estimated using real-world observations as well as a simulation routine to efficiently resolve temporal conflicts using an optimisation model. The framework is applied to the full-time workers of a synthetic population for the city of Lausanne, Switzerland. We validate the model results against reported schedules. The results demonstrate the capabilities of our approach to reproduce empirical observations in a real-world case study

Are interpersonal comparisons of utility indeterminate?

On the orthodox view in economics, interpersonal comparisons of utility are not empirically meaningful, and "hence" impossible. To reassess this view, this paper draws on the parallels between the problem of interpersonal comparisons of utility and the problem of translation of linguistic meaning, as explored by Quine. I discuss several cases of what the empirical evidence for interpersonal comparisons of utility might be and show that, even on the strongest of these, interpersonal comparisons are empirically underdetermined and, if we also deny any appropriate truth of the matter, indeterminate. However, the underdetermination can be broken non-arbitrarily (though not purely empirically) if (i) we assign normative significance to certain states of affairs or (ii) we posit a fixed connection between certain empirically observable proxies and utility. I conclude that, even if interpersonal comparisons are not empirically meaningful, they are not in principle impossible