Secondary Traumatization in Partners and Parents of Dutch Peacekeeping Soldiers.

This study examines secondary traumatization among 708 partners and 332 parents of Dutch peacekeepers (i.e., personnel who participated in military actions implemented by international organizations such as the United Nations). Partners or parents of peacekeepers with 4 levels of posttraumatic stress symptoms were compared on posttraumatic stress, health problems, the quality of the marital relationship, and social support. In comparison with partners of peacekeepers without posttraumatic stress disorder (PTSD) symptoms, partners of peacekeepers with PTSD symptoms reported more sleeping and somatic problems, reported more negative social support, and judged the marital relationship as less favorable. No significant differences were found for parents. Thus, peacekeepers' stress reactions were related to various problems of their partners. A systemic approach to the treatment of persons with PTSD appears appropriate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming and authorship ascription: When nonconscious goals turn into conscious experiences of self-agency.

The conscious experience of self-agency (i.e., the feeling that one causes one’s own actions and their outcomes) is fundamental to human self-perception. Four experiments explored how experienced self-agency arises from a match between nonconsciously activated outcome representations and the subsequent production of the outcome and explored specifically how implicit motivation to produce the outcome may impinge on this process. Participants stopped a rapidly presented sequence of colors on a computer screen. Subsequently, they were presented with what could be the color on which they had stopped the sequence or a color that was randomly chosen by the computer. Agency ratings after each trial revealed that priming outcomes (a specific color) just before the outcome was produced enhanced experienced self-agency. Importantly, priming outcomes relatively far in advance also augmented self-agency, but only if the outcome was attached to positive affect and thus operating as a nonconscious goal maintaining the outcome representation active over time. As such, these studies show how the mechanisms underlying nonconscious goal pursuit promote experiences of self-agency, thus integrating 2 lines of research that so far have led separate lives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How indirect supportive digital help during and after solving physics problems can improve problem-solving abilities

This study investigates the effectiveness of computer-delivered hints in relation to problem-solving abilities in two alternative indirect instruction schemes. In one instruction scheme, hints are available to students immediately after they are given a new problem to solve as well as after they have completed the problem. In the other scheme, hints are only available as worked out problems after students have finished their solution. The instruction schemes are supplied by means of a web-based program, Physhint, which supports the development of strategic knowledge [Pol, H. J., Harskamp, E. G., & Suhre, C. J. M. (2008). The effect of the timing of instructional support in a computer-supported problem-solving program for students in secondary physics education. Computers in Human Behavior, 24, 1156–1178]. This program supports novice problem solvers while undertaking physics problems concerned with forces by providing hints structured in accordance with Schoenfeld’s episodes [Schoenfeld, A. H. (1992). Learning to think mathematically: Problem solving, metacognition, and sense making in mathematics. In D. A. Grouws (Ed.), Handbook of research on mathematics teaching (pp. 224–270). New York: McMillan Publishing].     

Compensation of magnetic disturbances improves inertial and magnetic sensing of human body segment orientation.

This paper describes a complementary Kalman filter design to estimate orientation of human body segments by fusing gyroscope, accelerometer, and magnetometer signals from miniature sensors. Ferromagnetic materials or other magnetic fields near the sensor module disturb the local earth magnetic field and, therefore, the orientation estimation, which impedes many (ambulatory) applications. In the filter, the gyroscope bias error, orientation error, and magnetic disturbance error are estimated. The filter was tested under quasi-static and dynamic conditions with ferromagnetic materials close to the sensor module. The quasi-static experiments implied static positions and rotations around the three axes. In the dynamic experiments, three-dimensional rotations were performed near a metal tool case. The orientation estimated by the filter was compared with the orientation obtained with an optical reference system Vicon. Results show accurate and drift-free orientation estimates. The compensation results in a significant difference (p < 0.01) between the orientation estimates with compensation of magnetic disturbances in comparison to no compensation or only gyroscopes. The average static error was 1.4 degrees (standard deviation 0.4) in the magnetically disturbed experiments. The dynamic error was 2.6 degrees root means square.