Updating the trainability tests literature on Black–White subgroup differences and reconsidering criterion-related validity.

A number of applied psychologists have suggested that trainability test Black–White ethnic group differences are low or relatively low (e.g., Siegel & Bergman, 1975), though data are scarce. Likewise, there are relatively few estimates of criterion-related validity for trainability tests predicting job performance (cf. Robertson & Downs, 1989). We review and clarify the existing (and limited) literature on Black–White group differences on trainability tests, provide new trainability test data from a recent video-based trainability exam, and present archival data about how trainability test scores relate to cognitive ability, Black–White differences, and job performance. Consistent with hypotheses, our results suggest large correlations of trainability tests with cognitive ability (e.g., .80) and larger standardized ethnic group differences than previously thought (ds of 0.86, 1.10, and 1.21 for 3 samples). Results also suggest that trainability tests have higher validity than previously thought. Overall, our analysis provides a substantial amount of data to update our understanding of the use of trainability tests in personnel selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tracing the geographic origin of poultry meat and dried beef with oxygen and strontium isotope ratios

Two promising isotope ratios, the δ¹⁸O of the water fraction, as extracted by azeotropic distillation, and the ⁸⁷Sr/⁸⁶Sr of the ash fraction were tested for their applicability to determine the geographic origin. In two sampling phases, in total 78 fresh poultry breast meat and 72 dried beef samples, independent from each other and originating from different countries, were analysed. The δ¹⁸O was measured with isotope ratio mass spectrometry and the isotope abundance ratio of ⁸⁷Sr/⁸⁶Sr with a multicollector inductively coupled plasma mass spectrometer. With δ¹⁸O it was possible to distinguish (p < 0.001) poultry and dried beef samples according to their country of origin. The beef data suggests that the procedure of processing is of only low additional influence on δ¹⁸O and, if so, it seems to reduce the initial between-country differences. The ⁸⁷Sr/⁸⁶Sr ratio did not give sufficient indications for differentiation by geographic origin in either poultry meat or dried beef in the smaller, first phase, data set and was therefore not further tested.     

The benefits of an additional worker are task-dependent: assessing low-back injury risks during prefabricated (panelized) wall construction

Team manual material handling is a common practice in residential construction where prefabricated building components (e.g., wall panels) are increasingly used. As part of a larger effort to enable proactive control of ergonomic exposures among workers handling panels, this study explored the effects of additional workers on injury risks during team-based panel erection tasks, specifically by quantifying how injury risks are affected by increasing the number of workers (by one, above the nominal or most common number). Twenty-four participants completed panel erection tasks with and without an additional worker under different panel mass and size conditions. Four risk assessment methods were employed that emphasized the low back. Though including an additional worker generally reduced injury risk across several panel masses and sizes, the magnitude of these benefits varied depending on the specific task and exhibited somewhat high variability within a given task. These results suggest that a simple, generalizable recommendation regarding team-based panel erection tasks is not warranted. Rather, a more systems-level approach accounting for both injury risk and productivity (a strength of panelized wall systems) should be undertaken.     

High track density for magnetic disk drives with an "Embedded servo" positioning system

The CII-HB "Embedded servo" original technique for disk drive units (such as the D 160) allows operation at high track densities ( 800 TPI) and fast access time. The overall information needed for head displacement and positioning is provided by the data head itself, without any other transducer. Servo transitions, written between the data sectors, are arranged to provide gain information, track logical address, and fine position. This information is used by a microcomputer program to move the head rapidly to the desired track and to lock it in position within an instantaneous error of less than 3 μm (120 μm inches). Practical results are presented and compared with a theoretical model. Limitations and improvements are discussed.     

The use of force feedback and auditory cues for performance of an assembly task in an immersive virtual environment

Using an immersive virtual environment, this study investigated whether the inclusion of force feedback or auditory cues improved manipulation performance and subjective reports of usability for an assembly task. Twenty-four volunteers (12 males and 12 females) were required to assemble and then disassemble five interconnecting virtual parts with either auditory, force, or no feedback cues provided. Performance for the assembly task was measured using completion time and number of collisions between parts, while the users preferences across conditions were evaluated using subjective reports of usability. The results indicated that the addition of force feedback slowed completion time and led to more collisions between parts for males. In contrast, females exhibited no change in the mean completion time for the assembly task but did show an increase in collision counts. Despite these negative performance findings when adding force feedback, users did report perceived increases in realism, helpfulness and utility towards the assembly task when force feedback was provided. Unlike force feedback, the results showed that auditory feedback, indicating that parts had collided during the assembly task, had no negative performance effects on the objective measures while still increasing perceived realism and overall user satisfaction. When auditory cues and force feedback were presented together, performance times, number of collisions, and usability were not improved compared to conditions containing just auditory cues or force feedback alone. Based on these results, and given the task and display devices used in the present study, the less costly option of excluding auditory and force feedback cues would produce the best performance when measured by the number of collisions and completion time. However, if increased ratings of usability for an assembly task are desired while maintaining objective performance levels and reduced cost, then the inclusion of auditory feedback cues is best.     

Efficient Path-Space Differentiable Volume Rendering With Respect To Shapes

Differentiable rendering of translucent objects with respect to their shapes has been a long-standing problem. State-of-the-art methods require detecting object silhouettes or specifying change rates inside translucent objects—both of which can be expensive for translucent objects with complex shapes. In this paper, we address this problem for translucent objects with no refractive or reflective boundaries. By reparameterizing interior components of differential path integrals, our new formulation does not require change rates to be specified in the interior of objects. Further, we introduce new Monte Carlo estimators based on this formulation that do not require explicit detection of object silhouettes.     

Effects of different physical workload parameters on mental workload and performance

The design and evaluation of an occupational task should include an assessment of mental workload, since excessive levels of mental workload can cause errors or delayed information processing. Physically demanding work that is performed concurrently with a cognitive task may impact mental workload by impairing mental processing or decreasing performance. The primary objective of this study was to determine whether there is a differential effect of various types of physical activity on both mental workload and cognitive performance. Objective and subjective assessment tools (heart rate variability and visual analog scale) were used as indicators of mental workload, while correct responses during an arithmetic task reflected levels of performance. Thirty participants (ages 18-24 years) performed a combination of tasks inducing both physical and mental workload. Type of physical effort, frequency of movement, and force exertion level were manipulated to alter the workload associated with the physical activity. Changes in subjective ratings generally corresponded to changes in both performance on the arithmetic task and objective mental workload assessment. Some discrepancies occurred at the highest physical force exertion level as participants perceived an increase in effort to maintain the same level of performance. Further research is needed to determine the force exertion threshold, beyond which the physical effort required interferes with mental workload and/or cognitive performance.

Relevance to industry

Technological advancements have increased the requirement for many workers to execute cognitive tasks concurrently with physical activity. When designing and evaluating such situations it is important to determine the interactive effects of these activities. A simple, uni-dimensional tool is suggested as a screening tool to identify situations requiring excessive or increased mental workload that many degrade performance or place additional stress on the individual.     

Excretion of neuraminic acid-containing trisaccharides in the urine during pregnancy

The excretion of neuraminic acid-containing trisaccharides in the urine during the course of normal pregnancy was studied. Neuraminyl-lactose and neuraminyl-galactosyl-(l led to 4)-N-acetylglucosamine were identified, and their excretion patterns were analyzed by thin-layer and gas chromatography. A progressive increase in the outputs of these acidic oligosaccharides was observed during the course of pregnancy in all cases studied. Neuraminyl-lactose excretion increased threefold, from 13.7 +/- 1.75 to 37.1 +/- 2.56 mg/24 h, and neuraminyl-galactosyl-N-acetylglucosamine twofold, from 8.4 +/- 1.27 to 15.3 +/- 2.21 mg/24 h (Mean +/- S.E.).