Work stressors, role-based performance, and the moderating influence of organizational support.

As a test of the 2-dimensional model of work stressors, the present study proposed differential relationships between challenge stressors and hindrance stressors and role-based performance, which were expected to be moderated by organizational support. In a sample of 215 employees across 61 offices of a state agency, the authors obtained a positive relationship between challenge stressors and role-based performance and a negative relationship between hindrance stressors and role-based performance. In addition, organizational support moderated the relationship between challenge stressors and role-based performance but did not moderate the relationship between hindrance stressors and role-based performance. This suggests that organizations would benefit from increasing challenges in the workplace as long as they are supportive of employees and removing hindrances. Further implications for organizational theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improving classroom learning by collaboratively observing human tutoring videos while problem solving.

Collaboratively observing tutoring is a promising method for observational learning (also referred to as vicarious learning). This method was tested in the Pittsburgh Science of Learning Center’s Physics LearnLab, where students were introduced to physics topics by observing videos while problem solving in Andes, a physics tutoring system. Students were randomly assigned to three groups: (a) pairs collaboratively observing videos of an expert human tutoring session, (b) pairs observing videos of expert problem solving, or (c) individuals observing expert problem solving. Immediate learning measures did not display group differences; however, long-term retention and transfer measures showed consistent differences favoring collaboratively observing tutoring. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Posttraumatic stress disorder patients' readiness to change alcohol and anger problems.

Notes that recovery from combat-related posttraumatic stress disorder (PTSD) is often complicated by unacknowledged problems with alcohol and anger. 102 males combat veterans (aged 42–63 yrs) entering a residential PTSD rehabilitation program completed University of Rhode Island Change Assessment and process-of-change questionnaires based on J. O. Prochaska and C. C. DiClemente's transtheoretical model (TTM; J. O. Prochaska et al, 1992). Separate assessments were made for alcohol abuse and anger control. Four motivational subtypes were identified for both problems. Motivation to change alcohol problems was independent of that for anger. Relative to less-motivated peers highly motivated patients were more like to spontaneously identify alcohol or anger as problems in their life and made greater use of change strategies specified by the TTM. These results support extension of the TTM to anger management and to PTSD management. Treatment implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strain and the quantitative characterization of anisotropic microstructures

Microstructures exhibit both crystallographic and morphological anisotropy. The orientation distribution function (ODF) for P _L(t), the number of intersections per unit length of boundaries with test lines parallel to a unit vector. t. describes morphological anisotropy, the spatial distribution of internal interfaces that separate grains or phases. Weak anisotropy refers to a microstructure such that P _L(t) vs t is an ellipsoid. Coefficients of the direction cosines in the equation of the ellipsoid form a Cartesian tensor called the microstructural anisotropy tensor (MAT). This work develops a measure of internal total strain, the Eulerian finite grain strain tensor (EFGST), based on the MAT. The reference state for the EFGST is an isotropic network having the same surface area per unit volume, S _V, as the deformed specimen. Analysis of the deformation of the network of ferrite-ferrite boundaries in a specimen of 1020 steel deformed in uniaxial tension illustrates that the EFGST measured at the centroid of the gage section changes congruently with a similar measure of bulk deformation, both having principal axes aligned with those of the bulk deformation. However, the values of strain are not identical due to nonuniform deformation in the gage section after necking. CRAIG S. HARTLEY, formerly Program Manager, Air Force office of Scientific Research, Arlington, VA 22203.     

Comparison of Solid-Liquid and Liquid-Liquid Mass Transfer

Mass transfer from solutions of m-acetotoluide, phenacetin and salicylamide into a stationary solvent, water, was studied. A sharp concentration jump was found at the leading solute front for all three liquid-liquid systmes. A comparison was made between the mass transferred in solid-liquid and liquid-liquid systems. The dissolution of m-acetotoluide, phenacetin and salicylamide was compared with mass transfer of solute from solutions with concentrations C_i, 2C_i and C_s into the pure solvent. In all cases, the amount dissolved from the solid was approximated by the C_i or the 2C_i-solvent system with the amount transferred in the C_s-solvent system approximately 100 fold greater than was dissolved from the solid. It was concluded that a concentration much less than saturation exists at the solid-liquid interface and that dissolution of the three compounds studied is controlled by the rate of solvent interaction at the solid surface.     

Experimental comparison of silicon p+-n-p+ and Cr-n-p+ transit-time oscillators

Punchthrough transit-time diodes have been constructed with both Schottky-barrier and diffused-junction emitters. The microwave and d.c. characteristics of these devices are strikingly similar. Either construction technique appears to be suitable for the future development of low-noise microwave sources.     

Effect of surface oxidation on the thermionic work function of beryllium

The thermionic work functions of five different beryllium samples were studied as a function of the degree of surface oxidation. The state of oxidation of each sample was determined by visual observation and by analysis of x-ray diffraction patterns. The data were analyzed by the Schottky plot-Richardson plot method. One wire was completely oxidized to BeO and its Richardson work function was found to be 3.80±0.06 e V and the thermionic constant was 31 amps/cm²-K². From visual and x-ray analyses of the various samples, it is concluded that the lowest work function determined for any of the beryllium samples, 3.22±0.08 eV, is the closest to the work function of pure polycrystalline beryllium metal.This work was initiated under a contract with the U.S. Office of Naval Research, Power Branch. Completion of the study was made possible through a National Aeronautics and Space Administration Traineeship.     

Retention of raw data: A problem revisited.

Requested raw data from a sample of authors in 1 issue of 4 psychological journals which vary from "hard" to "soft" scientific methodology in the articles published. Despite differences between the authors in the "hard" and "soft" journals, replies indicate that at present there is a greater tendency toward sharing data than has been reported previously. (PsycINFO Database Record (c) 2010 APA, all rights reserved)