Further Validation of the Elemental Psychopathy Assessment - Short Form (EPA-SF) in a Large University Sample.

The purpose of the current study was to provide further validation of the short form of the Elemental Psychopathy Assessment (EPA-SF), which was developed on the basis of a general personality model, the Five Factor Model (FFM) of personality. This study evaluated the internal structure of the EPA-SF trait scales, and examined the EPA-SF scales against two other psychopathy measures, the Triarchic Psychopathy Measure (TriPM) and the Expanded Leveson Self-Report Psychopathy Scales (E-LSRP), as well as a general FFM measure, in a sample of 924 university students. Exploratory Structural Equation Modeling generally supported internal structure for EPA-SF scales, in that the 18 EPA-SF traits generally loaded onto their four respective domain scales: Antagonism, Emotional Stability, Inhibition and Narcissism. Tucker's congruence coefficients (.95-.99) indicated excellent replicability of the original structure. The EPA-SF total and domain scale scores also showed moderate to large correlations with TriPM, E-LSRP and FFM domain scales in a manner mostly consistent with conceptual expectations. Finally, EPA-SF trait scales were also mostly associated with their corresponding FFM trait scale counterparts. Overall, the EPA-SF scale scores showed evidence for good convergent and discriminant validity.

Blast-induced electromagnetic fields in the brain from bone piezoelectricity.

In this paper, we show that bone piezoelectricity-a phenomenon in which bone polarizes electrically in response to an applied mechanical stress and produces a short-range electric field-may be a source of intense blast-induced electric fields in the brain, with magnitudes and timescales comparable to fields with known neurological effects. We compute the induced charge density in the skull from stress data on the skull from a finite-element full-head model simulation of a typical IED-scale blast wave incident on an unhelmeted human head as well as a human head protected by a kevlar helmet, and estimate the resulting electric fields in the brain in both cases to be on the order of 10 V/m in millisecond pulses. These fields are more than 10 times stronger than the IEEE safety guidelines for controlled environments (IEEE Standards Coordinating Committee 28, 2002) and comparable in strength and timescale to fields from repetitive Transcranial Magnetic Stimulation (rTMS) that are designed to induce neurological effects (Wagner et al., 2006a). They can be easily measured by RF antennas, and may provide the means to design a diagnostic tool that records a quantitative measure of the head's exposure to blast insult.