Genetic and environmental mechanisms underlying stability and change in problem behaviors at ages 3, 7, 10, and 12.

Maternal ratings on internalizing (INT) and externalizing (EXT) behaviors were collected in a large, population-based longitudinal sample. The numbers of participating twin pairs at ages 3, 7, 10, and 12 were 5,602, 5,115, 2,956, and 1,481, respectively. Stability in both behaviors was accounted for by genetic and shared environmental influences. The genetic contribution to stability (INT: 43%; EXT: 60%) resulted from the fact that a subset of genes expressed at an earlier age was still active at the next time point. A common set of shared environmental factors operated at all ages (INT: 47%; EXT: 34%). The modest contribution of nonshared environmental factors (INT: 10%; EXT: 6%) could not be captured by a simple model. Significant age-specific influences were found for all components, indicating that genetic and environmental factors also contributed to changes in problem behavior. Understanding the origins, nature, and course of psychopathology across childhood is important for clinical purposes as well as for scientific purposes. Of particular clinical importance are the mechanisms underlying continuity. The longer an individual continues along a maladaptive pathway, the more difficult it is to reclaim a normal developmental trajectory (Sroufe, 1990). Further

Observations and models of inertial waves in the deep ocean

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February, 1980The structure of the inertial peak in deep ocean kinetic energy spectra is studied here. Records were obtained from Polymode arrays deployed in the Western North Atlantic Ocean (40°W to 70°W, 15°N to 42°N). The results are interpreted both in terms of local sources and of turning point effects on internal waves generated at lower latitudes. In most of the data, there is a prominent inertial peak slightly above f; however, the peak height above the background continuum varies with depth and geographical environment. Three classes of environment and their corresponding spectra emerge from peak height variations: class 1 is the 1500 m level near the Mid-Atlantic Ridge, with the greatest peak height of 18 db; class 2 includes (a) the upper ocean (depth less than 2000 m), (b) the deep ocean (depth greater than 2000 m) over rough topography, and (c) the deep ocean underneath the Gulf Stream, with intermediate peak height of 11.5 db; class 3 is the deep ocean over smooth topography, with the lowest peak height of 7.5 db. Near f, the horizontal coherence scale is 0(60 km) at depths from 200 m to 600 m, and the vertical coherence scale is O(200 m) just below the main thermocline. A one turning point model is developed to describe inertial waves at mid-latitudes, based on the assumption that inertial waves are randomly generated at lower latitudes (global generation) where their frequency-wavenumber spectrum is given by the model of Garrett and Munk (1972 a, 1975). Using the globally valid wave functions obtained by Munk and Phillips (1968), various frequency spectra near f are calculated numerically. The model yields a prominent inertial peak of 7 db in the horizontal velocity spectrum but no peaks in the temperature spectrum. The model is latitudinally dependent: the frequency shift and bandwidth of the inertial peak decrease with latitude; energy level near f is minimum at about 30° and higher at low and high latitudes. The observations of class 3 can be well-described by the model; a low zonal wavenumber cutoff is required to produce the observed frequency shift of the inertial peak. The differences between the global generation model and the observations of class 1 and class 2 are interpreted as the effects of local sources. A locally forced model is developed based on the latitudinal modal decomposition of a localized source function. Asymptotic eigensolutions of the Laplace's tidal equation are therefore derived and used as a set of expansion functions. The forcing is through a vertical velocity field specified at the top or bottom boundaries of the ocean. For white noise forcing, the horizontal velocity spectrum of the response has an inertial peak which diminishes in the far-field. With the forcing located at either the surface or the bottom, several properties of the class 2 observations can be described qualitatively by a combination of the global and local models. The reflection of inertial waves from a turbulent benthic boundary layer is studied by a slab model of given depth. Frictional effects are confined to the boundary layer and modelled by a quadratic drag law. For given incident waves, reflection coefficients are found to be greater than 0.9 for the long waves which contain most of the energy. This result suggests that energy-containing inertial waves can propagate over great distance as is required by the validity of the model of global generation.This work was supported by the National Science Foundation through grant OCE 76-80210 and its continuation OEE 78-19833

Kompetenzen zum selbstregulierten Lernen im Studium. Ergebnisse der Befragung von Expert(inn)en aus vier Studienbereichen

Kompetenzen zum selbstregulierten Lernen (SRL) gelten als zentrale Voraussetzung des Studienerfolgs. Bisher ist unklar, in welchen Situationen der Einsatz welcher SRL-Strategien als kompetent anzusehen ist. Auf Basis einer Onlinebefragung von 306 Expert(inn)en für das SRL werden im Beitrag quantitative Evidenzen zur relativen Bedeutung sowie zu den selbstregulativen Anforderungen unterschiedlicher Lernsituationen in vier Studienbereichen dargestellt. Ferner werden Expert(inn)enurteile zur relativen Eignung von SRL-Strategien in diesen Situationen berichtet. Die untersuchten Strategien wurden aus einem differenziert und umfassend konzipierten Arbeitsmodell abgeleitet, das einen integrativen Ansatz zur Konzeption und Struktur von SRL-Kompetenzen im tertiären Bereich liefert. (DIPF/Orig.)Competencies in self-regulated learning (SRL) are seen as central prerequisites for success in academic studies. It is still unclear as to which SRL strategies are most effective in which learning situations. Based on surveys conducted among 306 expert SRL practitioners, this work provides evidence regarding the relative importance, and SRL demands, of different learning situations in four fields of study. Furthermore, expert assessments regarding the relative fit of different SRL strategies in these situations are reported. The strategies examined here were derived from a differentiated and comprehensively conceptualized working model that provides an integrative approach to the design and structure of SRL competencies in higher education. (DIPF/Orig.