Prior meta-analyses investigating the relation between the Big 5 personality dimensions and job performance have all contained a threat to construct validity, in that much of the data included within these analyses was not derived from actual Big 5 measures. In addition, these reviews did not address the relations between the Big 5 and contextual performance. Therefore, the present study sought to provide a meta-analytic estimate of the criterion-related validity of explicit Big 5 measures for predicting job performance and contextual performance. The results for job performance closely paralleled 2 of the previous meta-analyses, whereas analyses with contextual performance showed more complex relations among the Big 5 and performance. A more critical interpretation of the Big 5-performance relationship is presented, and suggestions for future research aimed at enhancing the validity of personality predictors are provided.
The present review examined the relationship between conditions of massed practice and spaced practice with respect to task performance. A meta-analysis of 63 studies with 112 effect sizes yielded an overall mean weighted effect size of 0.46, indicating that individuals in spaced practice conditions performed significantly higher than those in massed practice conditions. Subsequent analyses, however, suggested that the nature of the task being practiced, the intertrial time interval, and the interaction between these two variables significantly moderated the relationship between practice conditions and performance. In addition, significantly higher effect sizes were found in studies with low methodological rigor as compared with those studies higher in rigor. Directions for future research and applications of the findings are discussed.
The photografting of porous three-dimensional materials has been achieved using a benzophenone-initiated surface photopolymerization within the pores of a macroporous polymer monolith contained in a fused silica capillary. Despite the relatively high thickness (100 µm or more) of the layer of material involved, the photografting process occurs efficiently throughout its cross section as confirmed by electron probe microanalysis. In addition, the use of photomasks during grafting enables the precise placement of specific functionalities in selected and predetermined areas of a single monolith for use in a variety of applications ranging from supported catalysis to microfluidics. For example, we have demonstrated the fast and selective incorporation of chains of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) into the irradiated areas of pores of a 100 µm thick monolith and monitored the extent of grafting through measurements of the electroosmotic flow afforded by the newly introduced ionized functionalities. Grafting of the porous polymer with 4,4-dimethyl-2-vinylazlactone was also successful and could be monitored visually by fluorescence measurements following fluorescent labeling of the grafted chains with Rhodamine 6G.
In an attempt to extend past goal setting research, the present study examined the influence of goal-performance discrepancies (GPDs), causal attributions, and temporal factors on the process of dynamic self-regulation. Goal revision processes were examined longitudinally in a sample of 100 varsity-level college track and field athletes over the course of an 8-week competitive season. The results indicate that an individual's GPD significantly predicted the amount of goal revision engaged in by the athletes, such that participants were more likely to lower their competition (proximal) and season (distal) goals when they failed to reach these goals and their respective GPDs were large. However, as hypothesized, this relationship was moderated by stability attributions and the temporal location of the individual with respect to the time period allotted for goal attainment. Implications for future research in the area of goal setting and dynamic self-regulation are discussed.
Quantitative EPMA (electron probe microanalysis) intensity
measurements require an accurate correction for the X-ray continuum
(or background) created by the Bremsstrahlung effect from the
primary electron beam. This X-ray continuum, as measured on
a wavelength-dispersive spectrometer at any particular wavelength,
is primarily a function of the mean atomic number of the material
being analyzed. One can calibrate the dependence of the continuum
on mean atomic number by measuring and curve fitting the X-ray
intensities at the analytical peak in pure elements, oxides,
and binary compound standards that do not contain any of the
analyte or any interfering elements and use that calibration
to calculate the X-ray background correction. For unknown samples,
the mean atomic number is determined from the elemental
concentrations calculated by the ZAF or φ(ρz) matrix
correction, and the fit regression coefficients are used
iteratively to calculate the actual background correction. Over
a large range of mean atomic number we find that the dependence
of the continuum intensity on mean atomic number is well described
by a second-order polynomial fit. In the case of low-energy
X-ray lines (<1 to 2 keV), this fit is significantly improved
by correcting the X-ray continuum intensities for absorption.
For major and most minor element analyses, the improved mean
atomic number background correction procedure presented in this
paper is accurate and robust for a wide variety of samples.
Empirical mean atomic number background data are presented for
a typical 10-element silicate and a 15-element sulfide analytical
set up that demonstrate the validity of the technique as well
as some potential limitations.
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