Modelling the leaching of Pb, Cd, As, and Cr from cementitious waste using PHREEQC

A leaching model was developed using the United States Geological Survey public domain PHREEQC geochemical package to simulate the leaching of Pb, Cd, As, and Cr from cementitious wastes. The model utilises both kinetic terms and equilibrium thermodynamics of key compounds and provides information on leachate and precipitate speciation. The model was able to predict the leaching of Pb, Cd, As, and Cr from cement in the presence of both simple (0.1 and 0.6M acetic acid) and complex municipal landfill leachates. Heavy metal complexation by the municipal landfill leachate was accounted for by the introduction of a monoprotic organic species into the model. The model indicated Pb and As were predominantly incorporated within the calcium silicate hydrate matrix while a greater portion of Cd was seen to exist as discrete particles in the cement pores and Cr (VI) existed mostly as free CrO4(2-) ions. Precipitation was found to be the dominant mechanism controlling heavy metal solubility with carbonate and silicate species governing the solubility of Pb and carbonate, silicate and hydroxide species governing the solubility of Cd. In the presence of acetic acid, at low pH values Pb and Cd acetate complexes were predominant whereas, at high pH values, hydroxide species dominated. At high pH values, the concentration of As in the leachate was governed by the solubility of Ca3(AsO4)2 with the presence of carbonate alkalinity competing with arsenate for Ca ions. In the presence of municipal landfill leachate, Pb and Cd organic complexes dominated the heavy metal species in solution. The reduction of As and Cr in municipal landfill leachate was crucial for determining aqueous speciation, with typical municipal landfill conditions providing the reduced forms of As and Cr.     

Mood-Induced Increases in Alcohol Expectancy Strength in Internally Motivated Drinkers.

This study investigated whether exposure to musical mood induction procedures (MMIP) differentially increases the strength of specific alcohol expectancies for coping motivated (CM) versus enhancement motivated (EM) drinkers. Participants were 86 undergraduates who had elevated scores on either the CM or EM subscale of the Drinking Motives Questionnaire (M. L. Cooper, 1994). Participants were randomly assigned to either a positive or negative mood condition. The Alcohol Craving Questionnaire (E. G. Singleton, S. T. Tiffany, & J. E. Henningfield, 1994) was administered at baseline and after MMIP to assess phasic changes in alcohol expectancy strength. Consistent with hypotheses, only CM drinkers in the negative mood condition reported increased relief expectancies, and only EM drinkers in the positive mood condition reported increased reward expectancies. Theoretical and clinical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Buehler and Welsh (2009).

Reports an error in A process model of adolescents' triangulation into parents' marital conflict: The role of emotional reactivity by Cheryl Buehler and Deborah P. Welsh (Journal of Family Psychology, 2009[Apr], Vol 23[2], 167-180). In the article “A Process Model of Adolescents’ Triangulation Into Parents’ Marital Conflict: The Role of Emotional Reactivity” by Cheryl Buehler and Deborah P. Welsh (Journal of Family Psychology, 2009, Vol. 23, No. 2, pp. 167–180), the abstract contains an error. The sample size for the study was 416 rather than 426. (The following abstract of the original article appeared in record 2009-04780-005.) This study examined adolescents' emotional reactivity to parents' marital conflict as a mediator of the association between triangulation and adolescents' internalizing problems in a sample of 2-parent families (N = 426). Four waves of annual, multiple-informant data were analyzed (youth ages 11–15 years). The authors used structural equation modeling and found that triangulation was associated with increases in adolescents' internalizing problems, controlling for marital hostility and adolescent externalizing problems. There also was an indirect pathway from triangulation to internalizing problems across time through youths' emotional reactivity. Moderating analyses indicated that the 2nd half of the pathway, the association between emotional reactivity and increased internalizing problems, characterized youth with lower levels of hopefulness and attachment to parents. The findings help detail why triangulation is a risk factor for adolescents' development and which youth will profit most from interventions focused on emotional regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age effects on social cognition: Faces tell a different story.

The authors administered social cognition tasks to younger and older adults to investigate age-related differences in social and emotional processing. Although slower, older adults were as accurate as younger adults in identifying the emotional valence (i.e., positive, negative, or neutral) of facial expressions. However, the age difference in reaction time was largest for negative faces. Older adults were significantly less accurate at identifying specific facial expressions of fear and sadness. No age differences specific to social function were found on tasks of self-reference, identifying emotional words, or theory of mind. Performance on the social tasks in older adults was independent of performance on general cognitive tasks (e.g., working memory) but was related to personality traits and emotional awareness. Older adults also showed more intercorrelations among the social tasks than did the younger adults. These findings suggest that age differences in social cognition are limited to the processing of facial emotion. Nevertheless, with age there appears to be increasing reliance on a common resource to perform social tasks, but one that is not shared with other cognitive domains. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Lanczos-based method for structural dynamic reanalysis problems

In this paper, a new solution method for the modified eigenvalue problem with specific application to structural dynamic reanalysis is presented. The method, which is based on the block Lanczos algorithm, is developed for multiple low rank modifications to a system and calculates a few selected eigenpairs. Given the solution to the original system Ax = λx, procedures are developed for the modified standard eigenvalue Problem (A + ΔA)x? = λ x?, where

• 1 ΔA = Σ_jBS_jB^T, where S_j = S ∈ ?^{p × p}, p ? n and B ∈ ?^{n × p} is constant for all the perturbations S_j.
• 2 ΔA = Σ_iΣ_j B_iS_jB_i^T, where B_i ∈ ?^{n × p} may vary with the pertubations S_j.

The procedures are then extended for the reciprocal and generalized eigenvalue problems so that they are directly applicable to the structural dynamic reanalysis problem. Numerical examples are given to demonstrate the applications of the method.     

The relationship between coping styles, performance, and responses to stressful scenarios in police recruits.

This study investigated the relationship between coping styles and police recruits' stress responses and performance during a stressful event and the relationship between coping styles and traumatic symptoms. Recruits participated in a simulated stressful policing situation and were scored by expert raters. Distress measures included biological and psychological indicators of stress. Coping styles were associated with subjective and physiological distress but not with performance. Different coping styles were associated with different patterns of traumatic symptoms in the participants. Police recruits appear to rely on their training and skill sets in stressful situations regardless of how they manage their emotional response. Furthermore, the results suggest that different posttraumatic stress disorder manifestations may represent different pathologies, each associated with a different style of coping. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Problem of Measurement Model Misspecification in Behavioral and Organizational Research and Some Recommended Solutions.

The purpose of this study was to review the distinction between formative- and reflective-indicator measurement models, articulate a set of criteria for deciding whether measures are formative or reflective, illustrate some commonly researched constructs that have formative indicators, empirically test the effects of measurement model misspecification using a Monte Carlo simulation, and recommend new scale development procedures for latent constructs with formative indicators. Results of the Monte Carlo simulation indicated that measurement model misspecification can inflate unstandardized structural parameter estimates by as much as 400% or deflate them by as much as 80% and lead to Type I or Type II errors of inference, depending on whether the exogenous or the endogenous latent construct is misspecified. Implications of this research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

MMPI and Rorschach: Three decades of research.

Research references on the Rorschach and the Minnesota Multiphasic Personality Inventory (MMPI) were counted for each year, 1950–1985, to analyze the trends noted by W. M. Reynolds and N. D. Sundberg (see record 1979-00119-001) and to test their prediction that research on personality tests would decline after 1971. Results show that there was a decline between 1971 and 1975. However, the number of Rorschach references leveled off after 1975, and there was a resurgence of interest in MMPI research. Recent data suggest that both tests continue to be popular topics for published research. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Breeding context and response to song playback in mockingbirds (Mimus polyglottos).

Northern mockingbirds (Mimus polyglottos) sing more during nest building than at any other time in the breeding cycle. Playback tests in which the songs of nest-building and unmated males were played to mated males during incubation and nest building were conducted to determine if nest-building song is a mate guarding signal. Analyses indicated no greater aggressive response to song during nest building versus incubation in mated males. Singing itself was never evoked by song playback, and neither mated nor unmated males responded differently to songs produced by unmated versus nest-building males. The aggressive responses of unmated males were greater than those of mated males nest building without offspring, and males nest building with older offspring present responded as much as unmated males and more than males nest building without offspring. Aggressive response to song playback in once-mated males, whose mates disappeared during the breeding season, did not change as much as two months after disappearance of the mate. Nonetheless, ambient song production increased significantly above that apparent in the same birds when mated. These experiments indicate that aggressive reaction to song playback fluctuates across breeding contexts but not as predicted by the use of song as a mate guarding signal and not in a manner that parallels natural fluctuations in song production. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship of racial stressors to blood pressure responses and anger expression in Black college students.

27 Black college students viewed 3 excerpts showing racist situations involving Blacks; anger-provoking, nonracist situations; and neutral situations. After each scene, blood pressure (BP) was taken; a mood checklist, the Framingham Anger Scale (S. Haynes et al; see PA, Vol 68:10702), and the Anger Expression Scale of C. Spielberger et al (1985) were administered. Analyses revealed that BP significantly increased during the presentation of racist stimuli but not of anger-provoking or neutral stimuli. Self-reports of state anger, as measured by the mood checklist, were significant for both the anger-provoking and racist stimuli. BP scores were significantly correlated to the 2 trait anger measures. Exposure to racist stimuli was associated with BP increases among Blacks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)