Pupillometric measurement of operator workload

Pupillometry as a method of measuring workload is described. Pupillometric measures provide an indication of momentary fluctuations in central nervous system excitability that occur as cognitive operations are performed; the magnitude of these changes may serve as a sensitive indicator of the workload imposed by cognitive tasks

Interstellar propagation and the isotopic composition of hydrogen in the galactic cosmic rays

Preliminary results of a study of the propagation of the quartet of stable isotopes of hydrogen and helium are reported. A mean pathlength of 7.5 + or - 0.5 g/sq cms at approximately 300 MeV/nucleon is required to explain the low energy deuterium spectrum. This pathlength is consistent with pathlengths derived from the elements with Z 2, but is a (He-3/He-4) measurement of Jordan and P. Meyer (1984). The propagation calculations reported here incorporate the preliminary results of an updated nuclear interaction cross section survey covering the period since the review by J. P. Meyer (1972)

Additions to the Checklist of the Illinois Spiders

Five families and 140 species of spiders not included in former Illinois checklists are recorded. Two of these families, Antrodiaetidae and Scytodidae, and 40 of the species have been cited in earlier revisionary or other literature. The families Oonopidae, Symphytognathidae (slat.) and Ctenidae, and the remaining 100 species of spiders are recorded from Illinois for the first time. Locality data are given as counties only, and months of capture of mature specimens are presented. The total known spider fauna of Illinois now stands at 500 species in 27 families

Probing physics students' conceptual knowledge structures through term association

Traditional tests are not effective tools for diagnosing the content and structure of students' knowledge of physics. As a possible alternative, a set of term-association tasks (the "ConMap" tasks) was developed to probe the interconnections within students' store of conceptual knowledge. The tasks have students respond spontaneously to a term or problem or topic area with a sequence of associated terms; the response terms and timeof- entry data are captured. The tasks were tried on introductory physics students, and preliminary investigations show that the tasks are capable of eliciting information about the stucture of their knowledge. Specifically, data gathered through the tasks is similar to that produced by a hand-drawn concept map task, has measures that correlate with inclass exam performance, and is sensitive to learning produced by topic coverage in class. Although the results are preliminary and only suggestive, the tasks warrant further study as student-knowledge assessment instruments and sources of experimental data for cognitive modeling efforts.Comment: 31 pages plus 2 tables and 8 figure

Physiological assessment of operator workload during manual tracking. 1: Pupillary responses

The feasibility of pupillometry as an indicator for assessing operator workload during manual tracking was studied. The mean and maximum pupillary responses of 12 subjects performing tracking tasks with three levels of difficulty (bandwidth of the forcing function were 0.15, 0.30 and 0.50 Hz respectively) were analysed. The results showed that pupillary dilation increased significantly as a function of the tracking difficulty which was reflected by the significant increase of tracking error (RMS). The present study supplies additional evidence that pupillary response is a sensitive and reliable index which may serve as an indicator for assessing operator workload in man-machine systems

A Checklist of Illinois Centipedes (Chilopoda): Supplement

(excerpt) Order SCOLOPENDROMORPHA Family CRYFTOPIDAE Subfamily CRYFTOPINAE Cryptops hyalinus Say 1821. (Fig. 2). B (Cook; Auerbach [1951]), C (Champaign) F (Hardin, Jackson, Johnson, Pope, Saline, Williamson), G (Jackson, Jefferson, Perry, Williamson), H (Clark), I (Randolph, Union), J (Alexander)

Fish and freshwater crayfish in streams in the Cape Naturaliste region and Wilyabrup Brook

No abstract availabl

Rocketdyne LOX bearing tester program

The cause, or causes, for the Space Shuttle Main Engine ball wear were unknown, however, several mechanisms were suspected. Two testers were designed and built for operation in liquid oxygen to empirically gain insight into the problems and iterate solutions in a timely and cost efficient manner independent of engine testing. Schedules and test plans were developed that defined a test matrix consisting of parametric variations of loading, cooling or vapor margin, cage lubrication, material, and geometry studies. Initial test results indicated that the low pressure pump thrust bearing surface distress is a function of high axial load. Initial high pressure turbopump bearing tests produced the wear phenomenon observed in the turbopump and identified an inadequate vapor margin problem and a coolant flowrate sensitivity issue. These tests provided calibration data of analytical model predictions to give high confidence in the positive impact of future turbopump design modification for flight. Various modifications will be evaluated in these testers, since similar turbopump conditions can be produced and the benefit of the modification will be quantified in measured wear life comparisons