The Situational Judgment Test Validity Void: Describing Participant Response Processes

Situational judgment tests (SJTs) are used to measure important components of professional competence that cannot be assessed via traditional tests of knowledge and skills. Despite their increasing popularity, there is a significant gap in the validity evidence and research on the response process to support how SJTs measure their intended constructs. This study evaluated an SJT to examine: (1) the factors that influence the response process, (2) the role of experience in the response process, (3) the role of contextual features in the response process, and (4) whether individuals attempt to identify the construct being assessed. Thirty participants—15 students and 15 pharmacists—completed a 12-item SJT designed to measure empathy. Each participant engaged in an uninterrupted think-aloud interview while they completed an SJT followed by a cognitive interview that asked specific questions about their decision-making process. Results of the qualitative and quantitative analyses suggest that the SJT response processes include the complex integration of comprehension, retrieval, judgments, and response selections. In addition, job-specific knowledge and experiences comprised a significant portion of the retrieval process. Moreover, there was evidence that SJTs are highly contextual and that item characteristics such as setting, actors, or relationships can influence the response process. There was limited evidence to suggest individuals attempt to identify the construct being assessed. In summary, this study provides a comprehensive evaluation of the response process involved in SJTs using rigorous qualitative methodologies and it contributes to foundational steps to generate the validity evidence necessary to aid in score interpretation and future research.Doctor of Philosoph

Reducing Moisture Swell of Densified Wood With Polycarboxylic Acid Resin

A water-soluble polycarboxylic acid (PCA) resin was assessed for ability to limit moisture swelling of densified wood. Aspen flakes were treated in 0 (control), 1, 5, 10, and 20% PCA resin solutions and drained for 1, 10, and 20-min time periods. Following treatments, flakes were compressed to roughly 50% strain at 170°C. The PCA content of flakes significantly increased with increasing concentration and drain time. Water absorption and thickness swell of flakes decreased with increasing PCA content. Both water absorption and thickness swell of untreated flakes were over 100%; but for PCA-treated flakes, water absorption and thickness swell as low as 45% and 16%, respectively, were achieved. Irreversible thickness swell decreased with increasing PCA content, while reversible thickness swell remained relatively constant. The swelling coefficient decreased with increasing PCA content, a behavior that often is associated with bulking agents for treated, uncompressed wood. However, dynamic mechanical analysis further suggested that PCA resin acts as a cross-linking agent to stabilize the position of the collapsed cell walls

Fundamental Aspects of Wood Deformation Pertaining To Manufacture of Wood-Based Composites

During processing, wood-based composites are pressed using extreme heat and pressure for varying lengths of time. Evidence exists that the environmental conditions under which the wood densifies can alter the properties of both the solid wood and the composite product. Given the larger number and extreme nature of variables that exist during composite manufacture, it is imperative that the deformation process be understood from a fundamental standpoint. The objective of this research was to determine the applicability of basic materials engineering theory to the viscoelastic deformation of wood in transverse compression under a variety of temperatures and moisture contents.Theories of cellular solids were used to model the nonlinear compression behavior of small wood elements. For low-density woods, it was determined that cellular collapse can result from elastic buckling of the cell wall. The dependence of inelastic behavior of the gross wood on the elastic properties of the cell wall allows the time, temperature, and moisture dependence to be modeled with classical linear viscoelastic theory of amorphous polymers. Time-temperature-moisture superposition was shown to be applicable to stress relaxation data collected for temperatures between 39 and 99 C and moisture contents between 3 and 16%. The shift factors derived were described using free volume and entropy-based equations. This research demonstrates that wood behaves similarly under those conditions to the general class of cellular amorphous polymers. This conclusion opens many possibilities for experimentally and mathematically modeling the pressing of wood-based composites

Temperature Dependence Of Wood Surface Energy

A thorough understanding of the wood surface is required to engineer adhesive bonding in composite applications. A surface analysis technique, dynamic contact angle (DCA) analysis, was used to examine the effects of temperature on the wood surface as measured by the contact angle and surface energy. A hydrophobic surface transition was found on the wood surface at 60 C, which coincides with the glass transition of lignin as measured by differential scanning calorimetry. The change in the surface at the glass transition can be attributed to the diffusion of nonpolar molecular groups to the surface. This could be the result of the migration and deposition of extractives, reorientation of macromolecules, or a combination of the two. Similar behavior has been observed in synthetic amorphous polymers. Although the surface of wood is complex, the results indicate that it can be investigated and understood like synthetic polymer materials

The User\u27s Guide Project: Giving Experiential Context to Research Papers

We announce the User\u27s Guide Project

Ultrasonic Plate Wave Evaluation of Natural Fiber Composite Panels

Two key shortcomings of current ultrasonic nondestructive evaluation (NDE) techniques for plywood, medium density fiberboard (MDF), and oriented strandboard are the reliance on empirical correlations and the neglect of valuable waveform information. The research reported herein examined the feasibility of using fundamental mechanics, wave propagation, and laminated, shear deformable plate theories to nondestructively evaluate material properties in natural fiber-based composite panels. Dispersion curves were constructed exhibiting the variation of flexural plate wave phase velocity with frequency. Based on shear deformable laminated plate wave theory, flexural and transverse shear rigidity values for solid transversely isotropic, laminated transversely isotropic, and solid orthotropic natural fiber-based composite panels were obtained from the dispersion curves. Axial rigidity values were obtained directly from extensional plate wave phase velocity. Excellent agreement (within 3%) of flexural rigidity values was obtained between NDE and mechanical testing for most panels. Transverse shear modulus values obtained from plate wave tests were within 4% of values obtained from through-thickness ultrasonic shear wave speed. Tensile and compressive axial rigidity values obtained from NDE were 22% to 41% higher than mechanical tension and compression test results. These differences between NDE and axial mechanical testing results are likely due to load-rate effects; however, these large differences were not apparent in the flexural and transverse shear comparisons. This fundamental research advances the state-of-the-art of NDE of wood-based composites by replacing empirical approaches with a technique based on fundamental mechanics, shear deformation laminated plate theory, and plate wave propagation theory

Multi-platform comparison of ten commercial master mixes for probe-based real-time polymerase chain reaction detection of bioterrorism threat agents for surge preparedness

The Centers for Disease Control and Prevention and United States Army Research Institute for Infectious Diseases have developed real-time PCR assays for the detection of bioterrorism threat agents. These assays all rely on a limited number of approved real-time PCR master mixes. Because the availability of these reagents is a critical element of bioterrorism preparedness, we undertook a joint national preparedness exercise to address the potential surge needs resulting from a large-scale bio-emergency. We identified 9 commercially-available potential alternatives to an existing approved master mix (LightCycler FastStart DNA Master HybProbes): the TaqMan Fast Universal PCR master mix, OmniMix HS, FAST qPCR master mix, EXPRESS qPCR SuperMix kit, QuantiFast Probe PCR kit, LightCycler FastStart DNA MasterPLUS HybProbe, Brilliant II FAST qPCR master mix, ABsolute Fast QPCR Mix and the HotStart IT Taq master mix. The performances of these kits were evaluated by the use of real-time PCR assays for four bioterrorism threat agents: Bacillus anthracis, Brucella melitensis, Burkholderia mallei and Francisella tularensis. The master mixes were compared for target-specific detection levels, as well as consistency of results among three different real-time PCR platforms (LightCycler, SmartCycler and 7500 Fast Dx). Realtime PCR analysis revealed that all ten kits performed well for agent detection on the 7500 Fast Dx instrument; however, the QuantiFast Probe PCR kit yielded the most consistently positive results across multiple real-time PCR platforms. We report that certain combinations of commonly used master mixes and instruments are not as reliable as others at detecting low concentrations of target DNA. Furthermore, our study provides laboratories the option to select from the commercial kits we evaluated to suit their preparedness needs

Multi-platform comparison of ten commercial master mixes for probe-based real-time polymerase chain reaction detection of bioterrorism threat agents for surge preparedness

The Centers for Disease Control and Prevention and United States Army Research Institute for Infectious Diseases have developed real-time PCR assays for the detection of bioterrorism threat agents. These assays all rely on a limited number of approved real-time PCR master mixes. Because the availability of these reagents is a critical element of bioterrorism preparedness, we undertook a joint national preparedness exercise to address the potential surge needs resulting from a large-scale bio-emergency. We identified 9 commercially-available potential alternatives to an existing approved master mix (LightCycler FastStart DNA Master HybProbes): the TaqMan Fast Universal PCR master mix, OmniMix HS, FAST qPCR master mix, EXPRESS qPCR SuperMix kit, QuantiFast Probe PCR kit, LightCycler FastStart DNA MasterPLUS HybProbe, Brilliant II FAST qPCR master mix, ABsolute Fast QPCR Mix and the HotStart IT Taq master mix. The performances of these kits were evaluated by the use of real-time PCR assays for four bioterrorism threat agents: Bacillus anthracis, Brucella melitensis, Burkholderia mallei and Francisella tularensis. The master mixes were compared for target-specific detection levels, as well as consistency of results among three different real-time PCR platforms (LightCycler, SmartCycler and 7500 Fast Dx). Realtime PCR analysis revealed that all ten kits performed well for agent detection on the 7500 Fast Dx instrument; however, the QuantiFast Probe PCR kit yielded the most consistently positive results across multiple real-time PCR platforms. We report that certain combinations of commonly used master mixes and instruments are not as reliable as others at detecting low concentrations of target DNA. Furthermore, our study provides laboratories the option to select from the commercial kits we evaluated to suit their preparedness needs