8,740 research outputs found
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
Designing Effective Questions for Classroom Response System Teaching
Classroom response systems (CRSs) can be potent tools for teaching physics.
Their efficacy, however, depends strongly on the quality of the questions used.
Creating effective questions is difficult, and differs from creating exam and
homework problems. Every CRS question should have an explicit pedagogic purpose
consisting of a content goal, a process goal, and a metacognitive goal.
Questions can be engineered to fulfil their purpose through four complementary
mechanisms: directing students' attention, stimulating specific cognitive
processes, communicating information to instructor and students via
CRS-tabulated answer counts, and facilitating the articulation and
confrontation of ideas. We identify several tactics that help in the design of
potent questions, and present four "makeovers" showing how these tactics can be
used to convert traditional physics questions into more powerful CRS questions.Comment: 11 pages, including 6 figures and 2 tables. Submitted (and mostly
approved) to the American Journal of Physics. Based on invited talk BL05 at
the 2005 Winter Meeting of the American Association of Physics Teachers
(Albuquerque, NM
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