Synthesis of nanostructured vanadium powder by high-energy ball milling: X-ray diffraction and high-resolution electron microscopy characterization

Vanadium metal powders, ball milled with different surfactants viz., stearic acid, KCl and NaCl, have been studied by X-ray diffraction and transmission electron microscopy. The surfactants alter the microstructural and morphological characteristics of the powders. Ball milling with stearic acid results in solid-state amorphization, while powders milled with KCl yield vanadium–tungsten carbide nanocomposite mixtures. NaCl proved to be an excellent surfactant for obtaining nanostructured fusion-grade vanadium powders. In order to understand the reaction mechanism behind any interstitial addition in the ball-milled powders, CHNOS analysis was performed.     

The Role of Self-Esteem and Social Support in the Relationship between Extraversion and Happiness: a Serial Mediation Model

Studies have documented that self-esteem and social support mediate the relationship between extroversion and happiness. Most of the studies, however, were conducted in a piecemeal fashion and have rarely evaluated the two mediators simultaneously. It is not clear whether the two mediating effects are equally important or one is greater than the other. Moreover, little attention has been given to the indirect effect of extraversion on happiness through self-esteem then social support (i.e., serial mediating effect). The present study attempts to bridge these gaps by proposing and testing a path model illustrating the mediating effects of self-esteem and social support on the linkage of extraversion and happiness. Undergraduate students (N = 311) completed measures of extroversion, social support, self-esteem, and happiness. Results showed that extraversion, self-esteem, and social support were significantly associated with happiness. As predicted, both self-esteem and social support mediated the relationship between extraversion and happiness, respectively. Results also supported the hypothesized serial mediating effect. In other words, extroverts tend to have high self-esteem which increases supports they receive from friends and family. The high social support, in turn, enhances happiness. Additionally, comparisons among the three indirect effects indicated that the effect of self-esteem was significantly greater than the other two effects. The findings not only shed light on the independent and accumulative mediating effects of self-esteem and social support, but also provide new insight into the difference in strength of the indirect effects.     

Criteria instability and the isolated option effect

In two-stage choices, decision makers often compare a new (isolated) option with the winner from the first stage. Previous research has identified a choice advantage for an isolated option, ostensibly due to loss aversion. We propose an alternative mechanism suggesting that instability of the criteria used in each choice stage is the main driver of the isolated option effect. Results from a series of experiments support the criteria instability account and not loss aversion as the explanation for the isolated option effect.     

Brainstem correlates of temporal auditory processing in children with specific language impairment

Deficits in identification and discrimination of sounds with short inter-stimulus intervals or short formant transitions in children with specific language impairment (SLI) have been taken to reflect an underlying temporal auditory processing deficit. Using the sustained frequency following response (FFR) and the onset auditory brainstem responses (ABR) we evaluated if children with SLI show abnormalities at the brainstem level consistent with a temporal processing deficit. To this end, the neural encoding of tonal sweeps, as reflected in the FFR, for different rates of frequency change, and the effects of reducing inter-stimulus interval on the ABR components were evaluated in 10 4–11-year-old SLI children and their age-matched controls. Results for the SLI group showed degraded FFR phase-locked neural activity that failed to faithfully track the frequency change presented in the tonal sweeps, particularly at the faster sweep rates. SLI children also showed longer latencies for waves III and V of the ABR and a greater prolongation of wave III at high stimulus rates (>30/sec), suggesting greater susceptibility to neural adaptation. These results taken together appear to suggest a disruption in the temporal pattern of phase-locked neural activity necessary to encode rapid frequency change and an increased susceptibility to desynchronizing factors related to faster rates of stimulus presentation in children with SLI.     

Gender Differences in Fear of Success Imagery and Other Achievement-Related Background Variables Among Medical Students

Gender differences in the background variablesof 95 male and 94 female (85 Asian-American and 104primarily Caucasian non-Asian American) medical studentsenrolled in Phase I of a BS/MD six-year medical program were investigated. Fear of successimagery, resultant achievement motivation and severaldemographic and achievement-related home, school,personal motivational variables were analyzed. Therewere no significant gender differences in most ofthe variables. However, during high school, women spentless time in watching TV (p < .000), more time instudying (p < .000), and perceived that their chores were minimized before examinations (p< .002), while during their medical study, their useof conversation with someone to cope with theirpressures and their perception of unique parentalsupport were higher than those of men (p < .05 andp < .01, respectively). Hours spent in studying andin watching TV during high school, and parents'minimizing chores before tests can discriminate about two-thirds of the students in their appropriategender (p < .000).     

Vulnerability of facial attractiveness perception to early and multi-year visual deprivation

Judgments of facial attractiveness invariably accompany our perception of faces. Even neonates appear to be capable of making such judgments in a manner consistent with adults. This suggests that the processes supporting facial attractiveness require little, if any, visual experience to manifest. Here we investigate the resilience of these processes to several years of early-onset visual deprivation. Specifically, we study whether congenitally blind children treated several years after birth possess the ability to rate facial attractiveness in a manner congruent to normally sighted individuals. The data reveal significant individual variability in the way each newly sighted child perceives attractiveness. This is in marked contrast to data from normally sighted controls who exhibit strong across-subject agreement in facial attractiveness ratings. This variability may be attributable, in part, to atypical facial encoding strategies used by the newly sighted children. Overall, our results suggest that the development of facial attractiveness perception is likely to be vulnerable to early visual deprivation, pointing to the existence of a possible sensitive period early in the developmental trajectory.