Modelling of steel fiber-reinforced concrete under multi-axial loads

Fifty-four plain concrete and steel fiber-reinforced concrete (SFRC) plate specimens containing 0.5%, 1.0% and 1.5% of hooked fibers were tested under biaxial compression. The experimental results obtained were used to verify a failure surface developed earlier by the authors for SFRC under multi-axial loads. An equation has also been proposed in this study to predict the strain at failure for SFRC under multi-axial loads, ε_ci. The proposed failure criterion and equation to predict ε_ci were incorporated into a constitutive model in a well-established finite-element software, ABAQUS. Experiments of SFRC plate specimens under multi-axial loads and beams under two-point load were modeled to illustrate the application of the failure surface to SFRC under varying load conditions. Good agreement between analytical and experimental results is observed.     

Maternal communication: Predictors of outcome at follow-up in a sample of children at high and low risk for depression.

Separate lines of investigation have shown the increased risk of dysfunction for children of depressed women and impaired interaction between depressed mothers and their children. The link between the two was examined in 57 children at high and low risk for depression. Children of unipolar depressed, bipolar depressed, chronically medically ill, and normal, mothers were evaluated at a 6-mo follow-up. Hierarchical regression analyses suggested a relation between maternal interaction behavior on 2 dimensions, task focus and affective quality, and children's subsequent depression and school behavior; academic performance was related only to affective quality of interaction. Chronic stress was predictive of more negative, critical maternal behavior, whereas depressed mood was associated with less task involvement. Maternal interactions are viewed as a marker of a complex, mutual process involving interpersonal relationships in an adverse environmental context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship of mother and child variables to child outcomes in a high-risk sample: A causal modeling analysis.

Children of depressed mothers are at risk for psychopathology, but most studies have failed to examine mediators of the effects, mutual influence of children and mothers on each other, and effects of children's own characteristics. Children, aged 8 to 16, of 64 mothers with recurrent unipolar or bipolar affective disorders, chronic medical illness, or no disorder were assessed on initial and 6-month follow-up measures. Structural equation modeling tested a model in which children's outcomes 6 months later were caused by maternal functioning (including depression symptoms, role adjustment, and observed positive interaction) and characteristics of the child. A reciprocal relationship was predicted between maternal functioning and child characteristics (including quality of interactions with the mother, self-concept, and age). Results supported the model; although maternal functioning is related to symptoms and dysfunction in children, characteristics of the child also contribute to maternal functioning in a cycle of negative mutual influence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of cognitive bias in depression.

Describes a procedure for the assessment of depressive distortion, a construct hypothesized by A. T. Beck (1967, 1976) to be a central mechanism in the cause and maintenance of dysphoria and other symptoms of depression. The questionnaire assesses Ss' interpretations of events depicted in brief stories and measures presence of a tendency to select the most negative, pessimistic, or self-deprecating response options. The psychometric properties of the procedure are reported, and validity issues are addressed. There was a consistent relation between scores on the Beck Depression Inventory and depressive–distortion scores across samples of 590 college students, 29 outpatients in therapy for depression, and 20 inpatients. From test–retest data, it appears that Ss with high scores on both depression and distortion had the highest levels of depression 8 wks after initial testing. Although the results confirm Beck's hypothesis of a characteristic cognitive bias in depression, research is needed to analyze the role of bias in maintaining depressed mood and to clarify the nature of the bias. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induction of CYP1A and DNA damage in the fathead minnow (Pimephales promelas) following exposure to biosolids

Biosolids (treated sewage sludge) are increasingly disposed of on land. Thus particle-sorbed and dissolved constituents have the potential to enter nearby watersheds. Although organic contaminants are known to be present in biosolids these are not currently regulated and little data exist on their potential toxicity to aquatic organisms. We exposed Pimephales promelas to two concentrations of biosolids (0.5 and 2.5 g l(-1)) for 28-days (static-renewal) and characterized contaminants present and the extent of CYP1A and DNA damage induction at various time points. Many organic contaminants were detected in the biosolids, with polycyclic aromatic hydrocarbons (PAHs) being the dominant class. Substantial levels of polybrominated diphenyl ethers (PBDEs) and nonylphenols (NPs) were also present. Significant induction of hepatic CYP1A protein compared with controls (P<0.05) was observed in both low (0.5 g l(-1)) and high (2.5 g l(-1)) exposed fish from Day 7. CYP1A levels peaked at Day 21 with 21-fold and 8-fold inductions over controls in high and low dose fish respectively. Induction of DNA damage in hepatocytes (single strand breaks as measured using the COMET assay) was observed in both exposures compared with controls on Days 14 and 28 (P<0.05). A significant correlation was found between CYP1A induction and DNA damage (Pearson correlation index, P<0.05). It is plausible that activation of PAHs may be responsible for the induction of CYP1A and resulting increase in DNA damage. Our data show the potential for detrimental effects in the event of exposure of aquatic organisms to biosolids and the need for further investigations of possible impacts due to constituents not covered by current guidelines.     

Developmental changes in the influence of assigned goals on cooperation and competition.

We examined developmental changes in the influence of social goals on cooperative and competitive behavior in children between the ages of 6 and 13. Children played a game with a neutrally instructed peer under cooperative and individualistic instructions. The tendency to engage in cooperative and combative moves and to use attentional words varied interactively with age, sex, order of instructions, instructions, and trials. Older children adapted their cooperative behavior to fit assigned goals when individualistic trials preceded cooperation trials, but younger children did not. Older children adapted their competitive behavior on two of five game trials, but younger children did not adapt their competitive behavior on any trials. We observed no developmental differences in the overall levels of cooperation and competition. However, younger children were more likely to use attentional words than older children, and both age groups used more attentional words under individualistic instructions than under cooperative instructions. The results suggest that older children were more flexible in adapting their social strategies to assigned goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An empirically derived inventory to measure social fears and anxiety: The Social Phobia and Anxiety Inventory.

The development, reliability, and discriminative ability of a new instrument to assess social phobia are presented. The Social Phobia and Anxiety Inventory (SPAI) is an empirically derived instrument incorporating responses from the cognitive, somatic, and behavioral dimensions of social fear. The SPAI high test–retest reliability and good internal consistency. The instrument appears to be sensitive to the entire continuum of socially anxious concerns and is capable of differentiating social phobics from normal controls as well as from other anxiety patients. The utility of this instrument for improved assessment of social phobia and anxiety and its use as an aid for treatment planning are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Non-soluble dietary fiber effects on lipid absorption and blood serum lipid patterns

Generalized effects of dietary fiber on lipid absorption and blood serum lipid patterns of humans have not been defined and may not even exist. The term dietary fiber covers a wide variety of materials with different chemical and physical characteristics. The ability of pectins and mucilages, often classed as soluble fibers, to lower blood and liver lipids has been demonstrated repeatedly and consistently. However, demonstrated hypolipidemic effects of feeding such non-soluble fibers as cellulose, hemicellulose and bran are by no means consistent. On the basis of pooled data, it appears that hypolipidemic response or non-response of humans to inclusion of non-soluble fibers in diets is in part related to the degree of fecal bulking as a result of in vitro water holding capacity and in part related to pre-study blood serum lipid levels of the individual subjects.