MORPHOLOGY OF BEDROCK STEP POOL SYSTEMS1

ABSTRACT: One-hundred-and-sixty step pools were examined that have developed in andesitic, basaltic, or dacitic lavas or in glaciofluvial sediments along several reaches of Soda Creek in the Three Sisters Wilderness of the Oregon High Cascades to determine whether such systems exhibit similar morphology. Pool shapes, sizes, and spacing were measured, and the hydraulic head loss calculated for each pool surface. Lithologic variations among 15 shape categories were not significant, but size attributes - length, depth, and area - of pools were systematically different by rock type. The energy lost at hydraulic jumps did not differ significantly among the four lithologies, suggesting that perhaps step pools represent similar stream channel adjustments in steep terrain.     

The effect of tailored information, goal setting, and tailored feedback on household energy use, energy-related behaviors, and behavioral antecedents

In this multidisciplinary study, an Internet-based tool was used to encourage households (N=189) to reduce their direct (gas, electricity and fuel) and indirect energy use (embedded in the production, transportation and disposal of consumer goods). A combination of tailored information, goal setting (5%), and tailored feedback was used. The purpose of this study was to examine whether this combination of interventions would result in (i) changes in direct and indirect energy use, (ii) changes in energy-related behaviors, and (iii) changes in behavioral antecedents (i.e. knowledge). After 5 months, households exposed to the combination of interventions saved 5.1%, while households in the control group used 0.7% more energy. Households exposed to the interventions saved significantly more direct energy than households in the control group did. No difference in indirect energy savings emerged. Households exposed to the interventions adopted a number of energy-saving behaviors during the course of the study, whereas households in the control group did so to a lesser extent. Households exposed to the interventions had significantly higher knowledge levels of energy conservation than the control group had. It is argued that if the aim is to effectively encourage household energy conservation, it is necessary to examine changes in energy use, energy-related behaviors and behavioral antecedents.     

Reliability and input-data induced uncertainty of the EPIC model to estimate climate change impact on sorghum yields in the U.S. Great Plains

Crop simulation models are frequently used to estimate the impact of climate change on crop production. However, few studies have evaluated the model performance in ways that most researchers practiced in climate impact studies. In this article, we examined the reliability of the EPIC model in simulating grain sorghum (Sorghum bicolor (L.) Moench) yields in the U.S. Great Plains under different climate scenarios, namely in years with normal or extreme temperature and precipitation. We also investigated model uncertainties introduced by input data that are not site-specific but commonly used or available for climate change studies. Historical field trial data of sorghum at the Mead Experimental Center, NE, were used for model evaluations. The results showed that overall model reliability was about 56%. The mean absolute relative error (absRE) was about 29%. The degree of accuracy and reliability varied with climate-classes and nitrogen (N)-treatments. The largest bias occurred in drought years (RE = ?25%) and the most unreliable results were found in N-0 treatment (reliability = 32%). There was more than 69% probability that input-data-induced uncertainties were limited to less than 20% of absRE. Our results support the application of the EPIC model to climate change impact studies in the U.S. Great Plains. However, efforts are needed to improve the accuracy in simulating crop responses to extreme water- and nitrogen-stressed conditions.     

Making sense of organizational change: Is hindsight really 20/20?

This qualitative study explores the conceptual links between 2 different approaches to managerial cognition, sensemaking and cognitive bias, in the context of organizational change. A longitudinal case study utilizing both real‐time assessments and retrospective sensemaking data from interviews with 26 hospital employees at 3 points in time was undertaken. Patterns related to individuals' retrospective accounts and real‐time assessments were identified and used to construct 4 prototypical narratives. Data analysis revealed that organizational change was not a markedly negative experience for most informants, which is contrary to the prevailing theme in the literature. This and other findings are discussed in terms of sensemaking and cognitive bias. This study makes 2 contributions to our understanding of how individual's experience and make sense of organizational change over time as (a) little is known about how the process of change unfolds over time at the individual level and (b) extant research has not investigated the extent to which individuals' retrospective sensemaking about organizational change reflects or diverges from their real‐time assessments over the course of the change. More broadly, the study provides insights and focused advice for management researchers regarding the use of retrospective data to understand individuals' perceptions of situations that have already occurred.     

Who gets the benefit of the doubt? The impact of causal reasoning depth on how violations of gender stereotypes are evaluated

A large body of research demonstrates that women encounter severe penalties for violating gender stereotypes. In this paper, we explore the conditions under which the reverse is true—when being subject to a stereotype can actually benefit a woman compared to a man who is not subject to the same stereotype. In particular, we suggest that in situations of causal ambiguity—uncertainty about the reasons that a behavior occurred—differences in how men and women are evaluated will be moderated by the extent to which observers engage in a low or a high level of deliberative causal reasoning. In 3 experimental studies, participants were asked to make judgments about an employee who violated a female gender stereotype by failing to provide help to a coworker when asked to do so, but the reasons for this behavior were unclear. When participants were prompted to engage in deliberative causal reasoning, women were evaluated more positively than men, but not in the absence of such a prompt. Moreover, when participants did engage in deliberative causal reasoning, the more positive evaluations of women compared to men were driven by participants' beliefs that women's behavior was due more to situational constraints than the same behavior by men.     

Is there a link between motor vehicle collisions and being a cigarette smoker in Canada? Analysis of survey data from Ontario from 2002 to 2014

Objective: Although most research on drugs and driving has focused on the use of alcohol and cannabis, research that has been conducted on cigarette smoking and collisions has found that smokers have an increased collision involvement. Studies dating from 1967 through 2013 have shown a crude relative risk of about 1.5 among smokers compared to nonsmokers. In Canada, the association between smoking and collisions has not been recently investigated. Studies that have examined the association between smoking and collisions often did not control for all confounding factors, such as alcohol use and driving exposure, which have been associated with increased collision rates. Additionally, a number of these studies were examined in countries and at times when prevalence of smoking was much higher than is currently the case in Canada. The purpose of this research is to examine the association between self-reported current smoking and past-year collision involvement, controlling for confounding factors, in a large representative sample of adult drivers in Ontario, Canada, from 2002 and 2014.

Method: Data are based on the Centre for Addiction and Mental Health (CAMH) Monitor, an ongoing, rolling telephone survey of Ontario adults that provides epidemiological surveillance of indicators related to alcohol, tobacco, and other drug use, as well as physical and mental health. The survey uses random-digit-dialing methods via Computer-Assisted Telephone Interview, with response rates over 50%.

Results: Prevalence of self-reported collision involvement within the past year for 2002–2014 was 8.6% among those who currently smoke compared to 6.5% of nonsmokers. Logistic regression analysis, controlling for the potential confounding effects of sociodemographics, driving exposure measures, drinking frequency, and hazardous alcohol use, found that the overall odds for collision involvement in the preceding year among current smokers for 2002–2014 was 1.27 (95% confidence interval [CI], 1.06–1.53) times that of nonsmokers.

Conclusions: These findings indicate that despite a substantial reduction in overall prevalence of smoking in Canada, smokers still have a significantly increased odds of collision involvement, even when controlling for alcohol and exposure. Additionally, the results are consistent with the increased odds/risks of motor vehicle collisions found in other countries.     

Climate change impacts in the Middle East and Northern Africa (MENA) region and their implications for vulnerable population groups

Regional Environmental Change - The Middle East and North Africa (MENA) region emerges as one of the hot spots for worsening extreme heat, drought and aridity conditions under climate change. A...     

Removal of mercury from sediment by ultrasound combined with biomass (transgenic Chlamydomonas reinhardtii)

As one of the most pervasive environmental problems, Hg pollution in sediment is particularly difficult to remediate because it cannot be decomposed. The application of ultrasound combined with biomass (transgenic Chlamydomonas reinhardtii (C. reinhardtii), a green alga) for the removal of Hg from model and contaminated sediments (Al₂O₃, α-HgS, and PACS-2 marine sediment) was investigated in this study. Ultrasound was found to enhance Hg release from Al₂O₃, α-HgS, and PACS-2 marine sediment into the aqueous phase compared to mechanical shaking. A transgenic C. reinhardtii (2AMT-2) expressing a plasmamembrane-anchored metallothionein polymer effectively recovered Hg(II) released into the aqueous phase by sonication over a broad pH range from 2.0 to 9.0. The results showed that this combined technique of ultrasound and alga biomass (2AMT-2) engineered for enhanced metal recovery was effective to remove Hg from solids and sediments, especially from Al₂O₃ and α-HgS with no natural organic matter. The results of this study are discussed with respect to the development of in situ remediation techniques for Hg-contaminated sediments.     

Kinetic limitations on tracer partitioning in ganglia dominated source zones

Quantification of the relationship between dense nonaqueous phase liquid (DNAPL) source strength, source longevity and spatial distribution is increasingly recognized as important for effective remedial design. Partitioning tracers are one tool that may permit interrogation of DNAPL architecture. Tracer data are commonly analyzed under the assumption of linear, equilibrium partitioning, although the appropriateness of these assumptions has not been fully explored. Here we focus on elucidating the nonlinear and nonequilibrium partitioning behavior of three selected alcohol tracers - 1-pentanol, 1-hexanol and 2-octanol in a series of batch and column experiments. Liquid-liquid equilibria for systems comprising water, TCE and the selected alcohol illustrate the nonlinear distribution of alcohol between the aqueous and organic phases. Complete quantification of these equilibria facilitates delineation of the limits of applicability of the linear partitioning assumption, and assessment of potential inaccuracies associated with measurement of partition coefficients at a single concentration. Column experiments were conducted under conditions of non-equilibrium to evaluate the kinetics of the reversible absorption of the selected tracers in a sandy medium containing a uniform entrapped saturation of TCE-DNAPL. Experimental tracer breakthrough data were used, in conjunction with mathematical models and batch measurements, to evaluate alternative hypotheses for observed deviations from linear equilibrium partitioning behavior. Analyses suggest that, although all tracers accumulate at the TCE-DNAPL/aqueous interface, surface accumulation does not influence transport at concentrations typically employed for tracer tests. Moreover, results reveal that the kinetics of the reversible absorption process are well described using existing mass transfer correlations originally developed to model aqueous boundary layer resistance for pure-component NAPL dissolution.