Crustal structure and surface-wave dispersion in Africa

In 1953, through cooperation of the Bernard Price Geophysical Institute of the University of the Witwatersrand and the University of Natal, a Columbia University-type long-period seismometer (To = 15 sec., Tg = 75 sec.) was installed in the seismological observatory of the University of Natal at Pietermaritzburg, Union of South Africa. This instrument was well situated for receiving surface waves from the shock in northern Algeria of September 9, 1954, and the aftershock next day, which was of such intensity that its seismogram supplemented that of the original shock for the larger phases. The dispersion of the Rayleigh waves from these seismograms can be measured with greater precision than has been practicable heretofore for continents, because the path is longer (7,890 km.) than any which has been available for a long-period vertical instrument, and is remarkably free from obvious anomalies such as major mountain ranges. The scarcity of suitable seismograms for the study of Raleigh-wave dispersion along continental paths is due to the fact that suitably placed long-period vertical seismographs have not been available until recently

Pre-service and Novice Teacher Self-Efficacy: A Tool to Understand and Further Develop Confidence for Impacting Change

Teacher efficacy measures a teacher’s perception of his or her capacity as a teacher and impacts teacher behavior in a number of different ways. This study examined teacher efficacy as well as pedagogical beliefs/practices in pre-service and novice in-service teachers to determine the nature of the relationship between the two. Results indicated that the novice in-service teachers demonstrated statistically significant higher scores on the efficacy measure. In regards to the relationship between pedagogy and efficacy, there was no statistically significant relation among the pre-service teachers but with the novice in-service teachers, efficacy was statistically significantly correlated with general instructional pedagogy

Seismic model study of refractions from a layer of finite thickness

Two dimensional model experiments on refractions from layers of finite thickness are described. Refractions can be unreliable for velocity and depth determinations when they occur with wavelengths which are large compared to the layer thickness. Discrepancies reported between refraction velocities and borehole velocities can be partially accounted for in this manner. Even simple two- and three-layer models can show such effects as misleading second arrivals, echeloning of travel time curves, masked layers, and selective absorption in the overburden

Quantification of the spatiotemporal microstructural organization of the human brain association, projection and commissural pathways across the lifespan using diffusion tensor tractography.

Using diffusion tensor tractography, we quantified the microstructural changes in the association, projection, and commissural compact white matter pathways of the human brain over the lifespan in a cohort of healthy right-handed children and adults aged 6-68 years. In both males and females, the diffusion tensor radial diffusivity of the bilateral arcuate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, corticospinal, somatosensory tracts, and the corpus callosum followed a U-curve with advancing age; fractional anisotropy in the same pathways followed an inverted U-curve. Our study provides useful baseline data for the interpretation of data collected from patients

Knowledge of Objective 'Oughts': Monotonicity and the New Miners Puzzle

In the classic Miners case, an agent subjectively ought to do what they know is objectively wrong. This case shows that the subjective and objective ‘oughts’ are somewhat independent. But there remains a powerful intuition that the guidance of objective ‘oughts’ is more authoritative—so long as we know what they tell us. We argue that this intuition must be given up in light of a monotonicity principle, which undercuts the rationale for saying that objective ‘oughts’ are an authoritative guide for agents and advisors