Modelling the effects of climate and flow regulation on ice‐affected backwater staging in a large northern river

In cold region environments, ice‐jam floods (IJFs) pose a severe risk to local communities, economies, and ecosystems. Previous studies have shown that both climate and regulation affect IJF probabilities, but their relative impacts are poorly understood. This study presents a probabilistic modelling framework that couples hydrologic and hydraulic models to assess the relative role of regulated and naturalized flows on ice‐affected backwater staging. The framework is evaluated at an IJF‐prone town on the Peace River in western Canada, which has been regulated since 1972. Naturalized flows were generated for the comparison, and ice‐affected backwater profiles were calculated along jams of varying length and location and for different combinations of model parameters and boundary conditions. Results show significant differences in backwater staging (~2 m for a return period of T = 1:10 year) between two study time periods (1973–1992 vs 1993–2012) as compared with two different hydraulic flow conditions (regulated vs naturalized), suggesting a larger role of climate than regulation in backwater staging. However, regulation was found to offset flood risk during the 1973–1992 period and exacerbate flood risk during the 1993–2012 period.     

Neutron Diffraction Studies of Phase Transformations between Tetragonal and Orthorhombic Zirconia in Magnesia-Partially-Stabilized Zirconia

Neutron powder diffraction and conventional dilatometry have been used to investigate the tetragonal-to-orthorhombic phase transformation and the orthorhombic-to-tetragonal reversion in a high-toughness magnesia-partially-stabilized zirconia. For this material, the onset temperature on cooling for the tetragonal-to-orthorhombic transformation (determined by dilatometry) was 192 K, and the reversion on subsequent heating occurred between 500 and 620 K. Neutron diffraction patterns were recorded at temperatures down to 19 K then up to 664 K, and analyzed by the multiphase Rietveld method to determine the amounts of different phases as well as their lattice parameters and unit-cell volumes. It is notable that, at its maximum, the orthorhombic phase amounted to 45% of the sample by weight. Length changes were measured, using pushrod dilatometers, in the temperature range 80 to 700 K. Length changes calculated from the neutron diffraction determinations of the proportions and unit-cell volumes of the different phases are in very good agreement with the directly measured values.     

Georg Forsters Entwurf einer „Wissenschaft vom Menschen“

The major focus of the article is on Georg Forster’s mode of elaborating a “science of man” in its theoretical and cultural contexts. The study aims at identifying Forster’s distinct interests in the specificity of mankind and his interpretation of both the reasons for its diversity and its different stages of development. Forster, the article argues, used a historicized version of Enlightenment natural history in order to analyse man as a natural as well as a cultural being. At the same time, put anachronistically, Forster constituted the reciprocity of physical and cultural anthropology. However, he differs from Enlightenment historical thinking in that he interprets history as a contingency. Finally, the article maintains that Forster deliberately conceived of the “science of man” as a multidisciplinary empirical science.     

Origin of endowments in public good games: The impact of effort on contributions.

Public good games provide an experimental environment for the study of social dilemmas. Typically, participants receive their endowments for the game from the experimenter. However, what if these endowments were earned rather than given as windfalls? Does the level of effort to earn the endowments influence contributions to the public good? Participants (n = 83) in a 2-stage experiment were required to earn their endowments through making either greater or lesser efforts. They were subsequently asked to play a linear public good game with the money. In contrast to the majority of previous studies undertaken, the participants in this experiment were not informed as to the asymmetry of the origin of the endowment. The results showed that contributions to the public good were less if endowments were earned with greater effort rather than with lesser effort. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Independent control of InAs quantum dot density and size on AlxGa1–xAs surfaces

Decoupling of InAs quantum dot (QD) size and density on Al_xGa_1?xAs surfaces (x = 0, 0.15, 0.30, and 0.45) is achieved by using a low growth rate and careful control of the temperature. The deposition rate of 0.01 μm/h, instead of 0.05 μm/h, allows the QDs to ripen with additional InAs deposition while the substrate temperature (490–520 °C) determines the QD density. On the GaAs surface, an increase of 10 °C results in an order of magnitude lower QD density. The increase of Al in the Al_xGa_1?xAs surfaces results in a higher dot density, lower dot size, and an increased size distribution. All surfaces show reduced QD density with increasing temperature and an identical zero dot density temperature at 523 °C. The GaAs surface shows increasing QD height with temperature while the Al_xGa_1?xAs surfaces show the opposite trend, but the InAs volume fraction in QDs for all surfaces decreases with increasing temperature, implying a more stable wetting layer. Increasing Al content also increases the InAs volume fraction in QDs, implying the wetting layer for all but the 520 °C samples is less than one monolayer. Photoluminescence samples demonstrate ground state QD energies above the GaAs bandedge.     

Fluorine depth profiling by high-resolution 1D magnetic resonance imaging

High-resolution magnetic resonance imaging (MRI) has been used, for the first time, to measure fluorine concentration profiles with a high spatial resolution (5 μm) along the full film depth of fluorinated polyurethane films. The MRI fluorine profiles were consistent with the results obtained by X-ray photoelectron spectroscopy (XPS) in combination with microtoming. MRI is a nondestructive and potentially quantitative technique for probing the spatial distribution of small quantities of fluorine in coatings and multi-layered systems.